Water Resources and Integrated Management of the United Arab Emirates (World Water Resources, 3) 3030316831, 9783030316839

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World Water Resources

Abdulrahman S. Alsharhan Zeinelabidin E. Rizk

Water Resources and Integrated Management of the United Arab Emirates

World Water Resources Volume 3

Series Editor V. P. Singh, Department of Biological and Agricultural Engineering & Zachry Department of Civil Engineering, Texas A&M University, USA

This series aims to publish books, monographs and contributed volumes on water resources in the world, with particular focus per volume on water resources of a particular country or region. With the freshwater supplies becoming an increasingly important and scarce commodity, it is important to have under one cover up to date literature published on water resources and their management, e.g. lessons learnt or details from one river basin may be quite useful for other basins. Also, it is important that national and international river basins are managed, keeping each country’s interest and environment in mind. The need for dialog is being heightened by climate change and global warming. It is hoped that the Series will make a contribution to this dialog. The volumes in the series ideally would follow a “Three Part” approach as outlined below: In the chapters in the first Part Sources of Freshwater would be covered, like water resources of river basins; water resources of lake basins, including surface water and under river flow; groundwater; desalination; and snow cover/ice caps. In the second Part the chapters would include topics like: Water Use and Consumption, e.g. irrigation, industrial, domestic, recreational etc. In the third Part in different chapters more miscellaneous items can be covered like impacts of anthropogenic effects on water resources; impact of global warning and climate change on water resources; river basin management; river compacts and treaties; lake basin management; national development and water resources management; peace and water resources; economics of water resources development; water resources and civilization; politics and water resources; water-energy-food nexus; water security and sustainability; large water resources projects; ancient water works; and challenges for the future. Authored and edited volumes are welcomed to the series. Editor or co-editors would solicit colleagues to write chapters that make up the edited book. For an edited book, it is anticipated that there would be about 12–15 chapters in a book of about 300 pages. Books in the Series could also be authored by one person or several co-authors without inviting others to prepare separate chapters. The volumes in the Series would tend to follow the “Three Part” approach as outlined above. Topics that are of current interest can be added as well. Readership Readers would be university researchers, governmental agencies, NGOs, research institutes, and industry. It is also envisaged that conservation groups and those interested in water resources management would find some of the books of great interest. Comments or suggestions for future volumes are welcomed. Series Editor: V. P.  Singh, Department of Biological and Agricultural Engineering & Zachry Department of Civil Engineering Texas A&M University USA. Email: [email protected] More information about this series at http://www.springer.com/series/15410

Abdulrahman S. Alsharhan • Zeinelabidin E. Rizk

Water Resources and Integrated Management of the United Arab Emirates

Abdulrahman S. Alsharhan Middle East Geological and Environmental Establishment Dubai, United Arab Emirates

Zeinelabidin E. Rizk University of Science and Technology of Fujairah Fujairah, United Arab Emirates

ISSN 2509-7385     ISSN 2509-7393 (electronic) World Water Resources ISBN 978-3-030-31683-9    ISBN 978-3-030-31684-6 (eBook) https://doi.org/10.1007/978-3-030-31684-6 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG. The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

I dedicate this volume to my mentors and friends, Professor Christopher G. St. C. Kendall (USA) and late Professor Alan E.A.M. Nairn, for their role in shaping my scientific career. (ASA) I dedicate this volume to the love of my life, my late wife, Dr. Nagda A. Obeid; may Allah rest her soul in peace. (ZER)

Foreword

I am very pleased to present this valuable book on the UAE water resources prepared by two distinguished scholars in the field of geology and hydrogeology, Prof. Abdulrahman Sultan Alsharhan and Prof. Zeinelabidin Elsayed Rizk. The sustainable management of water resources is a common global challenge for all countries but particularly so in an arid desert country such as the UAE with very little renewable water resources. As noted in detail in the book, there is an increasing challenge for the country to ensure provision of water—the basis of our survival—against rapidly growing demands and the onset of climate change. Researchers are aware of the challenges facing water resources in the UAE and are working with the federal and local government entities to help increase scientific understanding and find innovative solutions. The book is comprehensive and is comprised of 28 chapters, describing conventional and nonconventional water resources in the UAE, diagnosing the challenges facing these resources, and describing ways and means of water conservation through technical solutions and social practices. The book also includes several case studies on the use of remote sensing, geographic information systems, isotope hydrology, and modeling techniques utilized in water resource assessment in the UAE. Finally, the book analyzes the issue of water governance and discusses the importance of balancing water resource management and meeting the increasing water demand. This book is the first of its kind to be available in the UAE in the English language. It is a remarkable achievement and fills the knowledge gap in natural resource management in the Arab world and, particularly, in the UAE. It is a highly recommended read for students and scholars alike interested not only in water resource management but also in topics such as desertification and climate change. I congratulate the authors for developing this outstanding book and encourage others to follow their footsteps in contributing to the advancement of science in the UAE and to protect our precious natural resources. Minister of Climate Change and Environment, Thani Ahmed Al-Zeyoudi Ministry of Climate Change and Environment  Dubai, United Arab Emirates vii

Acknowledgments

The authors of this book would like to thank His Excellency (HE) Dr. Thani Ahmed Al Zeyoudi, Minister of Climate Change and Environment (MOCCAE), United Arab Emirates (UAE), for writing the foreword and for his kind and encouraging statements in introducing this book to the Arab and international readers. Without HE’s support, this publication would not have been possible. The authors would like to thank the Ministry of Climate Change and Environment (MOCCAE), Ministry of Energy (MoE), Federal Competitiveness and Statistics Authority (FCSA), National Center of Meteorology and Seismology (NCMS), Environment Agency-Abu Dhabi (EAD), Abu Dhabi Water and Electricity Authority (ADWEA), Dubai Electricity and Water Authority (DEWA), Sharjah Electricity and Water Authority (SEWA), and Federal Electricity and Water Authority (FEWA) for the information derived from their publications and websites, which were used in the preparation of this book. The authors would like to thank Prof. Warren W.  Wood, Michigan State University, East Lansing, Michigan, United States, for his kind revision of Chap. 24 on the application of national isotopes’ techniques for water resource investigations in the UAE. The authors thank Dr. Redouane Choukrallah, International Center for Biosaline Agriculture (ICBA), for his kind revision of Chap. 14 on water desalination: environmental impacts and brine management. Gratitude and appreciation are extended to the graduate students we have supervised and graduated from UAE University (UAEU) and Ajman University (AU), who now hold key positions in the ministries responsible for water resources, academic institutions, federal and local authorities, and public services. Their theses research and recent publications were used in this book. The authors would like to thank their families who have stood by their side and supported them to go ahead with this publication which has taken much of their time and effort. Special thanks to Dr. Ayman Z. Rizk for his help in running the iThenticate and Turnitin programs licensed for Ajman University on the book manuscript and provision of the PDF files three times for each chapter. The authors would like to thank the administrations and colleagues in their academic institutions for their continuous support and help. ix

Contents

Part I Introduction to Water Resources 1 Introduction to Water Resources of the United Arab Emirates........... .   3 2 Overview on Global Water Resources..................................................... .  17 2.1 Global Water Resources.................................................................   18 2.1.1 Conventional Water Resources.......................................   19 2.1.1.1 The World Oceans.........................................   19 2.1.1.2 Water Resources in Continents......................   19 2.1.1.3 Glaciers and Ice Sheets.................................   20 2.1.1.4 Groundwater..................................................   20 2.1.1.5 Lakes and Reservoirs.....................................   21 2.1.1.6 Swamps.........................................................   22 2.1.1.7 Rivers.............................................................   22 2.1.2 Nonconventional Water Resources.................................   22 2.1.2.1 Desalinated Water..........................................   22 2.1.2.2 Treated Wastewater........................................   24 2.1.3 Water Demands..............................................................   27 2.1.4 Water Challenges...........................................................   27 2.1.4.1 Demographic Drivers....................................   27 2.2 Water Resources in the Middle East and North Africa Region......   29 2.2.1 Conventional Water Resources.......................................   30 2.2.1.1 Surface Water................................................   32 2.2.1.2 Groundwater..................................................   33 2.2.2 Nonconventional Water Resources.................................   33 2.2.2.1 Desalinated Water..........................................   33 2.2.2.2 Treated Wastewater........................................   35 2.2.3 Water Demands..............................................................   35 2.2.4 Water Challenges...........................................................   35 2.3 Water Resources in the Arab Countries.........................................   36 2.3.1 Conventional Water Resources.......................................   42

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2.3.1.1 Surface-Water Resources...............................   42 2.3.1.2 Groundwater Resources................................   43 2.3.2 Nonconventional Water Resources.................................   43 2.3.2.1 Desalinated Water..........................................   44 2.3.2.2 Treated Wastewater........................................   44 2.3.2.3 Other Non-conventional Water Sources........   44 2.3.3 Water Demand................................................................   47 2.3.4 Water Challenges...........................................................   49 2.3.4.1 Overexploitation of Groundwater Resources......................................................   50 2.3.4.2 Sustainable Management of Groundwater Resources......................................................   50 2.3.4.3 Natural Variability of Water Resources.........   50 2.3.4.4 Shared Water Resources................................   51 2.3.4.5 Water Pollution..............................................   52 2.4 Water Resources in the Arabian Gulf Region................................   52 2.4.1 Conventional Water Resources.......................................   54 2.4.1.1 Surface Water................................................   54 2.4.1.2 Groundwater..................................................   54 2.4.2 Nonconventional Water Resources.................................   55 2.4.2.1 Desalinated Water..........................................   55 2.4.2.2 Wastewater Treatment and Reuse..................   56 2.4.3 Water Demand................................................................   57 2.4.4 Water Challenges...........................................................   58 2.4.4.1 Reduction of Water Losses............................   58 2.4.4.2 Industrial Water and Wastewater Management..................................................   58 References ................................................................................................   58

Part II Geomorphology and Geology 3 Geomorphology and Geology and Their Influence on Water Resources................................................................................... .  65 3.1 Main Topographic and Morphologic Features...............................   66 3.1.1 Mountains.......................................................................   66 3.1.2 Gravel Plains..................................................................   73 3.1.3 Sand Dunes....................................................................   80 3.1.4 Coastal Areas..................................................................   86 3.1.5 Drainage Basins.............................................................   88 3.2 General Overview of Aquifer Systems...........................................   89 3.3 Geologic History and Hydrogeologic Characteristics...................   94 3.3.1 Paleozoic Deposition and Water Occurrences................   95 3.3.2 Triassic Deposition and Water Potential........................   98 3.3.3 Jurassic Deposition and Water Potential........................   98 3.3.4 Cretaceous Deposition and Water Potential...................   99

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3.3.5 Cenozoic Deposition and Water Potential......................   99 3.4 Stratigraphic Units of Surface Outcrops........................................   102 3.5 Geologic Structures........................................................................   105 3.5.1 Surface Geologic Structures...........................................   105 3.5.1.1 Ru’us Al Jibal................................................   105 3.5.1.2 Dibba Zone....................................................   106 3.5.1.3 Northern Ophiolite Zone...............................   107 3.5.1.4 Southern Ophiolite Zone...............................   107 3.5.1.5 Hatta Zone.....................................................   107 3.5.1.6 Wadi Ham Line.............................................   107 3.5.1.7 Al Fayah Mountains......................................   108 3.5.1.8 Al Ain Mountains..........................................   108 3.5.2 Subsurface Geologic Structures.....................................   109 References ................................................................................................  109

Part III Climate and Water Balance 4 Climate Conditions and Their Impact on Water Resources................. .  115 4.1 Introduction....................................................................................   115 4.2 Solar Radiation...............................................................................   116 4.3 Air Temperature.............................................................................   116 4.4 Relative Humidity..........................................................................   128 4.5 Wind Speed....................................................................................   129 4.6 Evaporation....................................................................................   134 4.7 Evapotranspiration.........................................................................   139 4.8 Rainfall...........................................................................................   141 4.9 Global Warming and Climate Change...........................................   158 4.9.1 The Impacts of Climate Change.....................................   158 4.9.2 The UAE Efforts to Mitigate Climate Change...............   159 4.9.3 Changes of Temperature in the UAE.............................   161 4.9.4 National Communications..............................................   161 4.10 Impact of Climate Change on Water Resources.............................   163 4.10.1 Variations of Temperature and Rainfall.........................   163 4.10.2 Decline of Aquifer Recharge..........................................   166 4.10.3 Shortage of Irrigation Water...........................................   167 4.10.4 Depletion of Groundwater..............................................   167 4.10.5 Increase of Soil Salinity.................................................   168 4.11 Impact of Climate Change on Water-Resources Planning.............   169 4.12 Modeling Climate Change.............................................................   169 4.12.1 Water Demand................................................................   170 4.12.2 Water Supply..................................................................   171 4.12.3 Groundwater Supplies....................................................   172 References ................................................................................................  174

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5 Climatic Water Balance............................................................................ .  177 5.1 Introduction....................................................................................   177 5.2 Groundwater Recharge...................................................................   182 5.3 Hydraulic Conductivity..................................................................   184 5.4 Infiltration Capacity.......................................................................   186 References ................................................................................................  191 Part IV Conventional Water Resources 6 Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge............................................................................... .  195 6.1 Introduction....................................................................................   196 6.2 Morphometry.................................................................................   200 6.3 Surface Runoff...............................................................................   203 6.4 Rainfall–Runoff Relationship........................................................   203 6.5 Estimation of Runoff Volume.........................................................   209 6.6 Rainfall-Reservoir Storage.............................................................   212 6.6.1 Input Data.......................................................................   212 6.6.2 Model Calibration..........................................................   213 6.6.3 Storage Simulation.........................................................   213 6.7 Flash Floods...................................................................................   215 6.7.1 Flash Floods Hazard.......................................................   217 6.8 Recharge Dams..............................................................................   218 References ................................................................................................  230 7 Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value.............................................................................. .  231 7.1 Introduction....................................................................................   232 7.2 Locations of Springs......................................................................   232 7.3 Geologic Setting.............................................................................   233 7.4 Rainfall...........................................................................................   234 7.5 Springs’ Discharge.........................................................................   235 7.6 Rainfall-Discharge Relation...........................................................   238 7.7 Groundwater Levels–Discharge Relation......................................   239 7.8 Physical and Chemical Properties..................................................   241 7.8.1 Physical Properties.........................................................   242 7.8.2 Chemical Properties.......................................................   244 7.8.3 Spring Water–Groundwater Relationship......................   247 7.9 Springs’ Water Quality...................................................................   250 References ................................................................................................  254 8 Aflaj Systems: History and Factors Affecting Recharge and Discharge............................................................................................ .  8.1 Introduction....................................................................................   8.2 Aflaj History...................................................................................   8.2.1 Aflaj Construction and Maintenance..............................  

257 257 258 260

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8.2.1.1 Aflaj Construction.........................................   260 8.2.1.2 Aflaj Maintenance.........................................   263 8.2.2 Aflaj Administration.......................................................   264 8.3 Aflaj Discharge...............................................................................   268 8.3.1 Factors Affecting Discharge, Water Quality and Water Use................................................................   271 8.3.1.1 Climate Conditions........................................   271 8.3.1.2 Geologic Setting............................................   272 8.3.1.3 Human Activities...........................................   273 8.4 Aflaj Water Quality........................................................................   273 8.5 Aflaj Water Use..............................................................................   276 References ................................................................................................  279

9 Limestone Aquifers................................................................................... .  281 9.1 Northern Limestone Aquifer..........................................................   282 9.1.1 Geological Setting of Wadi Al Bih.................................   282 9.1.2 Hydrogeology of the Wadi Al Bih Basin.......................   284 9.1.3 Hydrogeochemistry........................................................   285 9.1.4 Isotope Hydrology..........................................................   286 9.1.5 Water Quality.................................................................   293 9.1.6 Water Problems..............................................................   296 9.2 Jabal Hafit Limestone Aquifer.......................................................   299 9.2.1 Hydrogeology of the Dammam Aquifer in Jabal Hafit..................................................................   300 9.2.2 Hydrogeochemistry........................................................   302 9.2.3 Isotope Hydrology..........................................................   303 9.2.4 Geothermal Energy of Groundwater..............................   304 9.2.5 Groundwater Uses..........................................................   304 9.3 Limestone Aquifers in the Western Region....................................   305 9.3.1 Simsima Aquifer............................................................   305 9.3.2 Umm Er Radhuma Aquifer............................................   306 9.3.3 Dammam Aquifer...........................................................   307 References ................................................................................................  307 10 Ophiolite Aquifer...................................................................................... .  311 10.1 Introduction....................................................................................   312 10.2 Geomorphologic and Geologic Features........................................   312 10.3 Morphometry.................................................................................   315 10.4 Geologic Setting.............................................................................   317 10.5 Geologic Structure.........................................................................   324 10.6 Hydrogeology.................................................................................   324 10.7 Effect of Lineaments on Groundwater Levels...............................   326 10.8 Effect of Lineaments on Groundwater Chemistry.........................   330 References ................................................................................................  332

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11 Gravel Aquifers......................................................................................... .  335 11.1 The Eastern Gravel Aquifer............................................................   336 11.1.1 Geomorphology and Geologic Setting...........................   336 11.1.2 Hydrogeology.................................................................   338 11.1.3 Geoelectrical Investigations...........................................   338 11.1.3.1 Wadi Al Ruheib.............................................   342 11.1.3.2 Wadi Dadnah.................................................   346 11.1.3.3 Wadi Basserah...............................................   347 11.1.3.4 Wadi Wurrayah..............................................   349 11.1.3.5 Wadi Al Tawiyean.........................................   351 11.1.4 Hydrogeochemistry........................................................   355 11.1.5 Isotope Hydrology..........................................................   361 11.1.6 Groundwater Uses..........................................................   362 11.2 The Western Gravel Aquifer...........................................................   364 11.2.1 Hydrogeology.................................................................   366 11.2.2 Hydrogeochemistry........................................................   370 11.2.2.1 Electrical Conductivity and Salinity..............   372 11.2.2.2 Systems of Groundwater Flow......................   373 11.2.2.3 Major Ions and Hypothetical Salts................   375 11.2.2.4 Hydrochemical Profiles.................................   375 11.2.2.5 Minor Ions.....................................................   376 11.2.2.6 Trace Constituents..........................................................   378 11.2.2.7 Hydrochemical Coefficients..........................   379 11.2.3 Isotope Hydrology..........................................................   381 11.2.4 Groundwater Evaluation................................................   385 References ................................................................................................  390 12 Liwa Quaternary Sand Aquifer............................................................... .  395 12.1 Introduction....................................................................................   396 12.2 Geologic Setting.............................................................................   398 12.2.1 Tertiary Sediments.........................................................   398 12.2.2 Quaternary Deposits.......................................................   399 12.3 Hydrogeology.................................................................................   400 12.4 Hydrogeochemistry........................................................................   403 12.5 Water Quality.................................................................................   415 12.6 Isotope Hydrology..........................................................................   422 References ................................................................................................  424 13 Sand-and-Gravel Aquifer System............................................................ .  13.1 Introduction....................................................................................   13.2 Geomorphology and Geology........................................................   13.3 Hydrogeology.................................................................................   13.3.1 Groundwater-Flow Systems...........................................   13.4 Hydrogeochemistry........................................................................   13.4.1 Major Ions......................................................................   13.4.2 Groundwater-Dissolved Salts.........................................  

427 428 428 429 431 432 433 437

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13.4.3 Groundwater Types........................................................   438 13.4.4 Hydrochemical Ratios....................................................   439 13.4.5 Water Uses.....................................................................   440 13.5 Isotope Hydrology..........................................................................   441 References ................................................................................................  451

Part V Non-conventional Water Resources 14 Water Desalination: Environmental Impacts and Brine Management............................................................................ .  455 14.1 Introduction....................................................................................   456 14.2 Desalination Technologies.............................................................   457 14.3 Environmental Challenges.............................................................   460 14.3.1 Physical Impacts.............................................................   460 14.3.2 Chemical Impacts...........................................................   460 14.3.3 Biological Impacts.........................................................   462 14.4 Alleviation Measures.....................................................................   462 14.4.1 Zero-Brine Discharge.....................................................   462 14.4.2 Solar Pond Technology..................................................   466 14.4.3 Use of Renewable Energy..............................................   468 14.4.4 Research and Development............................................   468 References ................................................................................................  468 15 Treated Wastewater: Quality Concerns and Potential Uses................. .  15.1 Introduction....................................................................................   15.2 Evolution of Wastewater Treatment...............................................   15.3 Wastewater Treatment Plants.........................................................   15.4 Quality of Treated Wastewater.......................................................   15.4.1 High Salinity..................................................................   15.4.2 Health Risks...................................................................   15.4.3 Biological Oxygen Demand...........................................   15.4.4 Sewage Sludge...............................................................   15.5 Reuse of the Treated Effluents.......................................................   15.6 Applications of Treated Wastewater...............................................   15.6.1 Environmental Use.........................................................   15.6.2 Urban Use......................................................................   15.6.3 Industrial Use.................................................................   15.6.4 Agricultural Use.............................................................   15.7 Regulations of Treated Wastewater................................................   15.7.1 Requirements for Treated Wastewater Used in Irrigation.....................................................................   15.7.2 Requirements for Treated Sludge Used for Irrigation...................................................................   15.8 Advantages of Treated-Sewage Water............................................   15.9 Limitations on Usage of Treated-Sewage Water............................  

471 471 472 476 477 477 481 482 482 482 483 483 483 484 484 484 485 486 486 487

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15.10 Public Awareness and Capacity Building.......................................   489 15.11 Wastewater Treatment in Abu Dhabi..............................................   490 15.11.1 Existing Wastewater Treatment Systems........................   491 15.11.2 Domestic Wastewater Production and Reuse.................   491 15.11.3 Industrial Wastewater Production...................................   492 15.12 Wastewater Treatment in Ras Al Khaimah....................................   492 15.12.1 Wastewater-Treatment Plants.........................................   492 15.12.2 Wastewater-Treatment Levels........................................   493 15.12.3 Uses of Treated Wastewater...........................................   493 15.12.4 Costs and Benefits of Wastewater Treatment.................   494 15.12.5 Treated-Wastewater Quality Parameters........................   494 15.12.6 Waste Disposal...............................................................   495 15.12.7 Health Risks...................................................................   495 References ................................................................................................  496

Part VI Water Challenges 16 Challenges Facing Water Resources........................................................ .  501 16.1 Introduction....................................................................................   502 16.2 Surface-Water Problems.................................................................   503 16.2.1 Floods.............................................................................   503 16.2.2 Springs...........................................................................   503 16.2.3 Aflaj................................................................................   504 16.3 Groundwater Problems...................................................................   504 16.3.1 Scarcity...........................................................................   504 16.3.2 Depletion........................................................................   505 16.3.3 Water Logging................................................................   508 16.3.4 Increasing Salinity..........................................................   509 16.3.5 Salt-Water Intrusion.......................................................   515 16.3.6 Water Hardness..............................................................   516 16.3.7 Unsuitability for Irrigation.............................................   517 16.3.8 Water Pollution...............................................................   518 16.3.9 Earthquake Hazard.........................................................   518 16.4 Problems Related to Water Desalination........................................   518 16.4.1 Disposal of Reject Brine................................................   519 16.4.2 Impact of Pollution on Water Desalination....................   522 16.4.2.1 Oil Pollution..................................................   522 16.4.2.2 Thermal Pollution..........................................   523 16.4.2.3 Algal Growth.................................................   524 16.4.2.4 Salinity Problems..........................................   525 16.4.2.5 Heavy-Metal Pollution..................................   526 16.5 Problems Related to Usage of Treated Sewage Water...................   526 References ................................................................................................  527

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17 Drinking Water: Sources, Standards and Quality Issues...................... .  531 17.1 Introduction....................................................................................   531 17.2 Drinking-Water Standards..............................................................   532 17.3 Sources of Drinking Water.............................................................   533 17.4 pH and TDS....................................................................................   538 17.5 Major Ions......................................................................................   538 17.5.1 Cations...........................................................................   538 17.5.2 Anions............................................................................   541 17.6 Minor Ions......................................................................................   541 17.7 Trace Elements...............................................................................   542 17.8 Drinking-Water Standards..............................................................   543 References ................................................................................................  546 18 Groundwater: Quality Degradation and Water Pollution.................... .  18.1 Wadi Al Bih Limestone Aquifer.....................................................   18.1.1 Introduction....................................................................   18.1.2 Field Work......................................................................   18.1.3 Chemical and Microbiological Analyses.......................   18.1.4 Microbiological Pollution..............................................   18.2 Al Ain Limestone Aquifer..............................................................   18.2.1 Introduction....................................................................   18.2.2 Field Work and Laboratory Analyses.............................   18.2.3 Discussion of Results.....................................................   18.3 Fujairah Ophiolite Aquifer.............................................................   18.3.1 Introduction....................................................................   18.3.2 Field Work and Laboratory Analyses.............................   18.3.3 Discussion of Results.....................................................   18.4 Eastern Gravel Aquifer...................................................................   18.4.1 Introduction....................................................................   18.4.2 Model Assumption and Simulations..............................   18.4.3 Discussion of Results.....................................................   18.5 Western Gravel Aquifer..................................................................   18.5.1 Introduction....................................................................   18.5.2 Satellite Images and Water-Resources Data...................   18.5.3 Discussion of Results.....................................................   18.6 Liwa Quaternary Sand Aquifer......................................................   18.6.1 Introduction....................................................................   18.6.2 Field Work and Laboratory Analyses.............................   18.6.3 Discussion of Results.....................................................   18.6.3.1 Sources of Nitrate..........................................   18.6.3.2 Land Use.......................................................   18.6.3.3 Major Ions Chemistry....................................   18.7 Quaternary Sand Aquifer in Ajman Emirate..................................   18.7.1 Introduction....................................................................   18.7.2 Field Work and Laboratory Analyses.............................  

549 550 550 550 550 552 555 555 555 556 558 558 559 559 560 560 562 563 567 567 568 568 569 569 571 571 571 572 573 574 574 576

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18.7.3 Discussion of Results.....................................................   576 18.7.3.1 Pollution Sources...........................................   577 18.7.4 Natural Factors...............................................................   578 18.7.4.1 Geographic Location.....................................   578 18.7.4.2 Climatic Conditions.......................................   578 18.7.4.3 Hydrogeologic Setting...................................   579 18.7.4.4 Groundwater Chemistry................................   580 18.7.5 Anthropogenic Factors...................................................   584 References ................................................................................................  586 Part VII Integrated Water Resources Management 19 Water Conservation and Integrated Management................................ .  593 19.1 Introduction....................................................................................   593 19.2 Flood-Water Conservation.............................................................   595 19.3 Groundwater Conservation............................................................   596 19.4 Desalinated Water..........................................................................   599 19.4.1 Demand Management....................................................   599 19.4.2 Supply Management......................................................   601 19.5 Treated Wastewater........................................................................   602 19.6 Technological Solutions and Social Practices................................   603 19.6.1 Controlling Water Wastage.............................................   604 19.6.2 Minimizing Water Loss..................................................   606 19.6.3 Sequential Water Use.....................................................   606 19.6.4 Water Tariffs...................................................................   606 19.6.5 Improved Planning.........................................................   607 19.6.6 Awareness.......................................................................   607 References ................................................................................................  608 20 Water Harvesting...................................................................................... .  20.1 Introduction....................................................................................   20.2 Traditional Water Harvesting Methods..........................................   20.2.1 Surface Water Harvesting...............................................   20.2.1.1 Rainwater Harvesting....................................   20.2.1.2 Barriers..........................................................   20.2.1.3 Habisas..........................................................   20.2.1.4 Berkas............................................................   20.2.2 Groundwater Harvesting................................................   20.2.2.1 Aflaj Systems.................................................   20.3 Modern Water Harvesting Methods...............................................   20.3.1 Surface Water Harvesting...............................................   20.3.1.1 Cloud Seeding...............................................   20.3.1.2 Artificial Rain................................................   20.3.1.3 Recharge Dams..............................................   20.3.2 Groundwater Harvesting................................................  

609 610 610 610 610 611 611 613 614 614 616 616 616 617 618 623

Contents

xxi



20.3.2.1 Artificial Recharge........................................   623 20.3.2.2 Aquifer Storage and Recovery......................   625 20.3.2.3 Subsurface Dams...........................................   628 References ................................................................................................  629 21 Advanced Agricultural Technologies....................................................... .  631 21.1 Introduction....................................................................................   631 21.2 Agriculture and Food Production...................................................   634 21.3 Sources of Irrigation Water............................................................   638 21.4 Irrigation Methods..........................................................................   639 21.4.1 Conventional Irrigation Methods...................................   639 21.4.2 Advanced Irrigation Methods........................................   640 21.4.2.1 Drip Irrigation...............................................   640 21.4.2.2 Sprinkler Irrigation........................................   643 21.4.2.3 Bubbles Irrigation..........................................   644 21.5 Protected Agriculture.....................................................................   645 21.6 Biosaline Agriculture.....................................................................   646 21.6.1 Water Conservation........................................................   648 21.6.2 Water Reuse...................................................................   649 21.6.3 Water Data......................................................................   649 21.6.4 Irrigation Efficiency.......................................................   649 21.6.5 Water Storage.................................................................   649 21.6.6 Seawater Use in Biofuel.................................................   650 21.7 Aquaculture and Hydroponics.......................................................   651 21.8 Agriculture and the Environment...................................................   651 21.9 Agriculture Policies........................................................................   651 References ................................................................................................  652 Part VIII Modern Techniques in Water Investigations 22 Application of Remote-Sensing Techniques for Water-Resources Investigations in the UAE......................................................................... .  657 22.1 Introduction....................................................................................   657 22.2 Image Processing...........................................................................   660 22.3 Image Enhancement.......................................................................   660 22.4 Information Extraction...................................................................   661 22.4.1 Infiltration Rate..............................................................   661 22.4.2 Uniformity Coefficient...................................................   663 22.4.3 Classification of Dune and Interdune Areas...................   665 22.4.4 Calculation of Natural Evaporation...............................   666 References ................................................................................................  666

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Contents

23 Application of GIS Techniques for Water Resources Investigations in the UAE......................................................................... .  669 23.1 Introduction....................................................................................   670 23.2 Geomorphology and Geology........................................................   672 23.2.1 Geomorphology.............................................................   672 23.2.2 Geologic Setting.............................................................   673 23.3 Hydrogeology and Hydrogeochemistry.........................................   673 23.3.1 Hydrogeology.................................................................   673 23.3.2 Hydrogeochemistry........................................................   675 23.4 GIS Model......................................................................................   676 23.4.1 Model Construction........................................................   677 23.4.2 Model Inputs..................................................................   678 23.4.3 Model Output.................................................................   678 References ................................................................................................  680 24 Application of Natural Isotopes Techniques for Water Resources Investigations in the UAE....................................................... .  683 24.1 Introduction....................................................................................   684 24.2 Sources of Rain Water....................................................................   686 24.3 Origin and Age of Groundwater.....................................................   688 24.4 Natural Isotopes in Groundwater...................................................   689 24.4.1 Wadi Al Bih Limestone Aquifer.....................................   690 24.4.2 Jabal Hafit Limestone Aquifer.......................................   690 24.4.3 Eastern Gravel Aquifer...................................................   692 24.4.4 Western Gravel Aquifer..................................................   692 24.4.5 Liwa Quaternary Sand Aquifer......................................   693 24.5 Source(s) of Increasing Groundwater Salinity...............................   695 24.6 Assessment of Groundwater Pollution...........................................   696 24.6.1 Oil-Field Brines..............................................................   696 24.6.2 Nitrate Pollution.............................................................   697 24.7 Efficiency of Groundwater Recharge Dams...................................   701 References ................................................................................................  702 25 Application of Modeling Techniques for Water-Resource Investigations in the UAE......................................................................... .  707 25.1 Introduction....................................................................................   707 25.2 Wadi Al Bih Model........................................................................   711 25.2.1 Model Assumptions........................................................   712 25.2.2 Boundary Conditions.....................................................   712 25.2.3 Input Data.......................................................................   714 25.2.4 Simulation......................................................................   714 25.2.4.1 Calibration.....................................................   715 25.2.4.2 Prediction......................................................   715 25.3 Groundwater Flow Models for the Al Ain Area.............................   717 25.3.1 Al Jaww Plain Model.....................................................   717 25.3.2 West Al Ain Model.........................................................   718 References ................................................................................................  720

Contents

xxiii

Part IX Water Governance 26 Water Governance in the UAE................................................................ .  725 26.1 Introduction....................................................................................   726 26.2 Historical Overview.......................................................................   726 26.2.1 Ministry of Agriculture and Fisheries............................   727 26.2.2 General Secretariat of UAE Municipalities...................   727 26.2.3 General Water Resources Authority...............................   727 26.2.4 Federal Environmental Agency......................................   728 26.2.5 Ministry of Environment and Water...............................   729 26.2.6 Ministry of Climate Change and Environment..............   729 26.3 Administrative Status of Water Authorities....................................   729 26.3.1 Federal Authorities.........................................................   730 26.3.1.1 Ministry of Climate Change and Environment...........................................   732 26.3.1.2 Ministry of Energy........................................   733 26.3.1.3 Federal Electricity and Water Authority........   733 26.3.1.4 National Center of Meteorology and Seismology.............................................   734 26.3.2 Local Authorities............................................................   734 26.3.2.1 Environment Agency of Abu Dhabi..............   735 26.3.2.2 Abu Dhabi Water and Electricity Authority.......................................................   735 26.3.2.3 Dubai Electricity and Water Authority..........   735 26.3.2.4 Sharjah Electricity and Water Authority........   736 26.3.2.5 Ras Al Khaimah Environment Protection and Development Authority..........................   736 26.3.2.6 Ajman Municipality and Planning Department....................................................   736 26.3.2.7 Umm Al Quwain Municipality......................   737 26.3.2.8 Fujairah Municipality....................................   737 26.4 Water Laws.....................................................................................   738 26.4.1 Conventional Water-Resources Laws.............................   740 26.4.1.1 Surface Water Laws.......................................   740 26.4.1.2 Groundwater Laws........................................   741 26.4.2 Nonconventional Water-Resources Laws.......................   744 26.4.2.1 Desalinated Water Laws................................   744 26.4.2.2 Treated Wastewater Laws..............................   745 26.5 Institutional Development..............................................................   750 26.5.1 Need for Federal Water Laws.........................................   752 26.5.2 Establishment of a Federal Water Authority..................   753 References ................................................................................................  753

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Contents

Part X Water Resources and Demand Management 27 Water Resources and Water Demands in the UAE................................ .  757 27.1 Introduction....................................................................................   757 27.2 Water Resources.............................................................................   760 27.2.1 Conventional Water Resources.......................................   760 27.2.1.1 Seasonal Floods.............................................   761 27.2.1.2 Springs...........................................................   762 27.2.1.3 Aflaj...............................................................   763 27.2.1.4 Groundwater..................................................   765 27.2.2 Non-conventional Water Resources...............................   776 27.2.2.1 Desalination Water........................................   776 27.2.2.2 Treated Wastewater........................................   779 27.3 Water Demands..............................................................................   781 27.3.1 Agricultural Water Demand...........................................   784 27.3.2 Municipal Water Demand..............................................   784 27.3.3 Industrial Water Demand...............................................   785 27.4 Demand-Supply Balance................................................................   785 27.4.1 Present Demand-Supply Balance...................................   785 27.4.2 Future Demand-Supply Balance....................................   785 27.4.3 Future Water Demand....................................................   785 27.4.4 Future Water Supply.......................................................   786 27.5 Integrated Water Resources Management Strategy........................   786 References ................................................................................................  788 28 Conclusions................................................................................................ .  28.1 Introduction....................................................................................   28.2 Overview on Global Water Resources...........................................   28.3 Geomorphology and Geology........................................................   28.4 Climate Conditions and Their Impact on Water Resources...........   28.5 Climatic Water Balance..................................................................   28.6 Seasonal Floods..............................................................................   28.7 Natural Springs..............................................................................   28.8 Aflaj Systems.................................................................................   28.9 Limestone Aquifers........................................................................   28.10 Ophiolite Aquifer...........................................................................   28.11 Gravel Aquifers..............................................................................   28.11.1 The Eastern Gravel Aquifer............................................   28.11.2 The Western Gravel Aquifer...........................................   28.12 Liwa Quaternary Sand Aquifer......................................................   28.13 Sand-and-Gravel Aquifer System...................................................   28.14 Desalinated Water..........................................................................   28.15 Treated Wastewater........................................................................   28.16 Challenges Facing Water Resources..............................................   28.17 Drinking Water...............................................................................   28.18 Groundwater Pollution...................................................................  

793 793 794 796 797 799 800 801 801 803 804 806 806 807 809 810 812 813 813 815 815

Contents



xxv

28.19 Water Conservation and Integrated Management..........................   817 28.20 Water Harvesting............................................................................   818 28.21 Advanced Agricultural Technologies.............................................   819 28.22 Application of Remote-Sensing Techniques..................................   820 28.23 Application of GIS Techniques for Water Resources.....................   821 28.24 Application of Natural Isotopes to Water Resources.....................   821 28.25 Application Modeling Techniques for Water Resources................   823 28.26 Water Governance..........................................................................   825 28.27 Water Resources and Water Demand.............................................   826 References ................................................................................................  826

Index................................................................................................................... .  831

Abbreviations

AADC Al Ain Distribution Company AAS Atomic Absorption Spectrophotometry ACI American Concrete Institute ACSAD Arab Center for the Studies of Arid Zones and Dry Lands ADDC Abu Dhabi Distribution Company ADSSC Abu Dhabi Sewerage Services Company AED United Arab Emirates dirham ADWEA Abu Dhabi Water and Electricity Authority ADWEC Abu Dhabi Water and Electricity Company ADFCA Abu Dhabi Food Control Agency AMPD Ajman Municipality and Planning Department amsl Above mean sea level AOAD Arab Organization for Agricultural Development As Arsenic ASR Aquifer Storage Recovery AUST Ajman University of Science and Technology AW Arab world B Boron BOD Biochemical oxygen demand Br Bromide BSA Bismuth sulfite agar BWRO Brackish water reverse osmosis GCC Gulf Cooperation Council Cd Cadmium Cr Chromium Calcium ion Ca2+ Ca(HCO3)2 Calcium bicarbonate Calcium sulfate CaSO4 Calcium carbonate CaCO3 14 C Carbon 14

xxvii

xxviii

CEDARE

Abbreviations

Center for Environment and Development for the Arab Region and Europe CDM Clean Development Mechanism Chloride ion Cl− Carbon dioxide CO2 CCS Carbon capture and storage Carbon dioxide per cubic meter CO2/m3 CFCl3 Trichlorofluoromethane CFCs Chlorofluorocarbons Co Cobalt CH4 Methane CPDPs Cogeneration Power Desalination Plants Uniformity coefficient Cu Cu Copper DC Direct current DEWA Dubai Electricity and Water Authority DM Dubai Municipality DP Desalination plant 2D Two-dimensional 3D Three-dimensional DLR German Aerospace Center DO Dissolved oxygen Drainage density Dd DS-1 DubaiSat DST Defined substrate technology DEM Digital elevation model DWEA Dubai Electricity and Water Authority EAD Environment Agency-Abu Dhabi ECA Eastern coastal area ECCD Energy and Climate Change Directorate EDSA Eastern drainage southern area EGDC Emirates Green Development Council EMR Eastern mountain ranges ECC Energy and climate change EPA Environmental Protection Agency EPD Environmental Protection Department EPDA Environment Protection and Development Authority DRDAS Earth Resources Data Analysis System ESCWA Economic and Social Commission for Western Asia ESRI Environmental Systems Research Institute Effective grain size d50 EC Electric conductance EDN Effluent distribution network EC Electrical conductivity ED Electrodialysis

Abbreviations

ERWDA Environment Research and Wildlife Development Authority ESCWA Economic and Social Commission for Western Asia ET Evapotranspiration Fluoride ion F − FAO Food and Agriculture Organization Fe Iron FE Finite element Fs Stream frequency ET Evapotranspiration FCSA Federal Competitiveness and Statistics Authority FEA Federal Environmental Agency FEWA Federal Electricity and Water Authority EDTA Ethylenediaminetetraacetic acid FAO Food and Agriculture Organization FM Fujairah Municipality FWA Federal Water Authority GIS Geographic information systems GMWL Global meteoric water line GCMs Global climate models GP Gravel plain GPD Gallon per day GCC Gulf Cooperation Council GDP Gross domestic product GHGs Greenhouse gases GMWL Global meteoric water line COM Cabinet of Ministers GSM General Secretariat of Municipalities GSO GCC Standardization Organization GWI Global Water Intelligence GWRA General Water Resources Authority GWRO Groundwater reverse osmosis 2 H Deuterium 3 H Tritium Hydrogen sulfide H2S HMS Hydrologic Modeling Center HGA HydroGeoAnalyst Bicarbonate ion HCO3− t½ Half-life time dh/dl Hydraulic gradient ICBA International Center for Biosaline Agriculture IAEA International Atomic Energy Agency ICP-AES Inductively coupled plasma-atomic emission spectrometry Ic Infiltration capacity IP Induced polarization IPCC Intergovernmental Panel on Climate Change

xxix

xxx

Abbreviations

IDA International Desalination Association IRENA International Renewable Energy Agency Ir Infiltration rate ISO International Organization for Standardization IWA International Water Association IWRM Integrated water resources management lpcpd Liters per capita per day IAEA International Atomic Energy Agency IWACO International Workshop on Aliasing, Confinement and Ownership JICA Japan International Cooperation Agency K Hydraulic conductivity Potassium ion K+ KCl Potassium chloride Km Kilometer kg Kilogram Ks Hydraulic conductivity of the soil layer LDAS Land data assimilation systems L/d Liters per day L/Sec Liter per second Pb Lead Li Lithium LMWL Local meteoric water line MMWL Mediterranean meteoric water line Ωm Ohm meter M Meter MAF Ministry of Agriculture and Fisheries Mn Manganese Magnesium ion Mg2+ μS/cm Microsiemens per centimeter Mn Manganese MAR Managed aquifer recharge MAF Ministry of Agriculture and Fisheries μg /L Micrograms per liter Mo Molybdenum MOE Ministry of Energy MOEW Ministry of Environment and Water MSF Multistage flash MOFA Ministry of Foreign Affairs (MOCCAE) Ministry of Climate Change and Environment mg/L Milligram per liter MCM Million cubic meters MENA Middle East and North Africa MEW Ministry of Electricity and Water MED Multi-effect distillation MMWL Mediterranean meteoric water line

Abbreviations

MPMR Ministry of Petroleum and Mineral Resources MSP Methane serpentinized peridotites MIST Masdar Institute of Science and Technology MIG Million imperial gallons Magnesium chloride MgCl2 MWE Ministry of Water and Electricity Sodium ion Na+ NGOs Nongovernmental organizations NH3 Ammonia NH4− Ammonium NO2− Nitrite NO3− Nitrate NO3−-N Nitrate-Nitrogen 15 N Nitrogen-15 isotope NaCl Sodium chloride Effective porosity Ne Ni Nickel NASA National Aeronautics and Space Administration NCMS National Centre of Meteorology and Seismology NF Nanofiltration NDC National Drilling Company Nitrous oxide N2O Ammonium chloride NH4Cl 18 O Oxygen 18 O3 Ozone Pb Lead PET Potential evapotranspiration pH Hydrogen ion concentration PO32− Phosphate ppb Part per billion ppm Part per million Ps Water surplus R Groundwater recharge RSB Regulation and Supervision Bureau 226 Rd Radium 222 R Radon Bifurcation ratio Rb RO Reverse osmosis RS Remote sensing STP Sewage treatment plant Sc Storage coefficient SC Specific capacity Se Selenium SEPA Sharjah Environment and Protected Areas Authority Sr Strontium

xxxi

xxxii

Sy SPC SEWA SPOT

Abbreviations

Specific yield Sewage Projects Committee Sharjah Electricity and Water Authority Earth observation satellite (French: Satellite Pour l’Observation de la Terre) SWRO Seawater reverse osmosis SWI Saltwater intrusion SWS Schlumberger Water Services SAR Sodium adsorption ratio Specific yield Sy SOS Slow-release oxygen source Sr Strontium Se Selenium Storage coefficient Sc Stream frequency Fs Sulfate ion SO42− TDEM Time-domain electromagnetic method TDS Total dissolved solids TH Total hardness T Transmissivity TEM Transient electromagnetics TDEM Transient-domain electromagnetics TA Total alkalinity TH Total hardness TDS Total dissolved solids (TDIC) Total dissolved inorganic carbon TM Thematic mapper TPH Total petroleum hydrocarbon TRANSCO Abu Dhabi Transmission & Despatch Company TSS Total suspended solids TU Tritium unit UN United Nations UAE United Arab Emirates UAEU United Arab Emirates University UAQ Umm Al Quwain UAQM Umm Al Quwain Municipality UNDP United Nations Development Program UNESCO United Nations Educational, Scientific and Cultural Organization USGS United States Geological Survey UPC Urban Planning Council UTM Universal Transverse Mercator VES Vertical electrical soundings VRBA Violet red bile agar WDC World Dam Commission WDCA Western Drainage Central Area

Abbreviations

WDNA Western Drainage Northern Area WHO World Health Organization WMO World Meteorological Organization WWF World Wide Fund Zn Zinc

xxxiii

List of Figures

Fig. 2.1 Fig. 2.2 Fig. 2.3 Fig. 2.4 Fig. 2.5 Fig. 2.6 Fig. 2.7 Fig. 2.8 Fig. 2.9 Fig. 2.10 Fig. 2.11 Fig. 2.12 Fig. 2.13 Fig. 2.14

Distribution of the world’s water. (Modified after Salih 1997; Dai 2012)......................................................... 18 Groundwater resources of the world. (After Taylor et al. 2013)............................................................. 21 World water desalination capacity in Mm3/day and percent. (After Escobar and Schäfer 2010)............................................... 23 Water-desalination capacities in the Arabian Gulf in m3/day. (Modified from Lattemann and Hopner 2003; Escobar and Schäfer 2010; UNDP 2013)................................................. 24 Water-desalination capacities in the Red Sea. (Modified from Lattemann and Hopner 2003; Escobar and Schäfer 2010; UNDP 2013)................................... 25 Water-desalination capacities in the Mediterranean. (Modified from Lattemann and Hopner 2003; Escobar and Schäfer 2010; UNDP 2013)................................... 26 The world usage of treated and untreated wastewater for irrigation. (After Lautze et al. 2014)..................................... 26 The growth of the percentage of people living in urban areas around the globe in 2005 and 2030. (After UN 2007)....... 29 Mean annual rainfall in MENA region. (After Terink et al. 2013)............................................................. 30 The annual per capita share of natural water resources in the MENA region. (After the World Bank 2007).................... 31 Share of water available or used, by source, in the MENA region. (After World Bank 2007).......................... 31 Volume of water resources available, by source, in MENA region. (After the World Bank 2007).......................... 32 Percentage of water resources available, by source, in MENA region. (The World Bank 2007).................................. 32 Share of national water demand in MENA countries met by desalination in 2010. (After the World Bank 2012)........ 34 xxxv

xxxvi

Fig. 2.15 Fig. 2.16

Fig. 2.17 Fig. 2.18 Fig. 2.19 Fig. 2.20 Fig. 2.21 Fig. 2.22 Fig. 2.23 Fig. 2.24 Fig. 2.25 Fig. 2.26 Fig. 2.27 Fig. 3.1 Fig. 3.2 Fig. 3.3 Fig. 3.4 Fig. 3.5 Fig. 3.6 Fig. 3.7 Fig. 3.8

List of Figures

The annual global growth of desalination by technology between 2006 and 2016. (After the World Bank 2012).............. 35 (a) The total percentage of renewable water resources withdrawn in various regions (top), and (b) actual renewable freshwater resources per capita (1000 m3/year) by region (below). (After the World Bank 2007)...................................................... 37 The variability of rainfall in the MENA countries. (After the World Bank 2007)...................................................... 38 Rainfall distribution in the Arab World. (After UNDP 2013)..... 39 Total renewable water resources per capita, by country. (After the World Bank 2009)...................................................... 42 Present and contracted desalinated-water capacity in some Arab countries. (After UNDP 2013).......................................... 44 Decrease in the cost of MSF plants during the period 1955–2003. (After UNDP 2013)................................................. 45 Comparison of the RO, MSF and MED costs of operation. (After UNDP 2013)..................................................................... 46 Treated wastewater produced in various Arab countries during 2009–2010. (After UNDP 2013)..................................... 46 The per capita in renewable water in the Arab World. (After UNDP 2013)..................................................................... 50 Observed depletion in the groundwater level of the Saïss basin in Morocco during the period 1963–2007. (After UNDP 2013)..................................................................... 51 Rainfall Index for various Arab countries. (After UNDP 2013)..................................................................... 51 Per capita availability trends in the GCC countries for the period 1970–2010. (After the World Bank 2005)............ 53 Simplified topographic map of the United Arab Emirates.......... 66 Geomorphologic map for the United Arab Emirates. (Simplified from the UAE National Atlas 1993)......................... 67 Map showing the distribution and types of sand dunes in the United Arab Emirates. (Modified from the UAE National Atlas 1993)................................................................... 82 Major drainage basins and locations of groundwater-recharge dams in the Eastern Region of the United Arab Emirates........... 90 Map showing the main aquifer systems in the United Arab Emirates. (After Rizk et al. 1997)..................................... 94 Simplified geologic map of the United Arab Emirates. (Modified from the UAE National Atlas 1993)........................... 95 Geologic boundaries and depositional basins in the Arabian Peninsula. (Alsharhan 1989)....................................................... 96 Strategraphic sequence and hydrogeologic properties of rock units in the United Arab Emirates and the Gulf Cooperation Council (GCC) countries. (Modified from Alsharhan 1989)...... 97

List of Figures

Fig. 3.9 Fig. 3.10 Fig. 3.11 Fig. 3.12 Fig. 4.1 Fig. 4.2 Fig. 4.3a Fig. 4.3b Fig. 4.4a Fig. 4.4b Fig. 4.5a Fig. 4.5b Fig. 4.6 Fig. 4.7 Fig. 4.8a Fig. 4.8b Fig. 4.9 Fig. 4.10a

xxxvii

Stratigraphy of rock outcrops in the mountainous areas of the United Arab Emirates. (After Warrak 1987; Alsharhan 1989).......................................................................... 102 Map showing the major structural zones affecting groundwater resources in the Eastern Region of the United Arab Emirates. (After Alsharhan 1989)............................................................... 103 Map showing shallow geologic structures and traces of buried paleochannels in the Al Ain Area, Eastern Region of the UAE. (After Woodword 1994).............................................................. 104 Map showing major subsurface geologic structures in the United Arab Emirates. (After Alsharhan 1989)................ 109 Locations of the main meteorological stations in the United Arab Emirates........................................................ 121 Mean minimum, mean and mean maximum annual solar radiation (kWh/m2) for the period 2003–2015................... 121 Mean minimum, mean and mean maximum monthly air temperature (°C) for the period 1976–2003........................... 124 Mean minimum, mean and mean maximum monthly air temperature (°C) for the period 2003–2015........................... 124 Mean minimum, mean and mean maximum monthly relative humidity (%) for the period 1976–2003......................... 128 Mean minimum, mean and mean maximum monthly relative humidity (%) for the period 2003–2015......................... 129 Mean minimum and mean wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 1976–2003............................................................ 134 Mean minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 2003–2015............................................................ 134 Mean minimum, mean and mean maximum monthly evaporation (mm) for the period 1976–2003.............................. 139 Calculated monthly potential evapotranspiration, mm, at 11 major meteorological stations in the UAE in 1988. (Data from Garamoon 1996)....................................................... 140 Mean minimum, mean and mean maximum monthly rainfall (mm) in UAE for the period 1976–2005........................ 143 Mean minimum, mean and mean maximum monthly rainfall (mm) in UAE for the period 2003–2015........................ 143 Average monthly rainfall (in mm) records in 34 metrological stations in UAE during the period 2003–2014............................ 144 Mean annual rainfall (mm) records for the period 1976–2003, showing the wide variation in average annual rainfall in 19 meteorological stations...................................................... 145

xxxviii

Fig. 4.10b Fig. 4.11 Fig. 4.12 Fig. 4.13 Fig. 4.14

Fig. 4.15

Fig. 4.16

Fig. 4.17

Fig. 4.18

Fig. 4.19 Fig. 4.20 Fig. 4.21 Fig. 4.22 Fig. 4.23 Fig. 4.24

List of Figures

Mean annual rainfall (mm) records for the period 2003–2015, showing the wide variation in average annual rainfall in 30 meteorological stations...................................................... 145 Mean annual rainfall (mm) records for the period 1935–2015, showing the ten-­year cycles; at the end of each cycle, rainfall exceeds the annual mean................................................ 151 Predicted recurrence of rainfall maxima and minima, based on the records of 20 years of rainfall................................ 151 Iso-hyetal contour map of annual rainfall in the United Arab Emirates for the period 1976–2015.................................... 152 Deviations from the mean annual rainfall (mm) in the meteorological stations of Al Burayrat, Sharjah airport and Falaj Al Mualla in the Northern Region of the United Arab Emirates for the period 1976–2003............................................. 153 Deviations from the mean annual rainfall (mm) at the meteorological stations of Al Dhaid, Meleiha and Al Hibab in the Central Region of the United Arab Emirates for the period 1976–2003............................................. 154 Deviations from the mean annual rainfall (mm) at the meteorological stations of Al Ain, Al Oha and Al Wagan in the Southern Region of the United Arab Emirates for the period 1976–2003........................ 155 Deviations from the mean annual rainfall (mm) at the meteorological stations of Dibba, Masafi and Masfut in the Eastern Region of the United Arab Emirates for the period 1976–2003............................................................ 156 Deviations from the mean annual rainfall (mm) in the meteorological stations of Abu Dhabi, Dubai and Asab in the Western Region of the United Arab Emirates for the period 1976–2003............................................. 157 Global average temperature and carbon dioxide (CO2) trends. (After Karl and Trenberth 2003)........................... 160 Annual time series for all variables for selected stations in the United Arab Emirates. (After Ouarda et al. 2014)............ 164 Rainfall and mean temperature of the Ras Al Khaimah Emirate for the period 1977–2014. (After Murad et al. 2014)................. 165 Measurements of groundwater Salinity in Wadi Al Bih basin in 2005, 2011 and 2014. (After Murad et al. 2014)........... 165 Total annual precipitation of the three climate change scenarios for the Abu Dhabi Emirate. (After Dougherty et al. 2009)......... 170 The future annual water demand for the Emirate of Abu Dhabi under various scenarios during the period 2000–2025. (After Dougherty et al. 2009)...................... 170

List of Figures

Fig. 4.25 Fig. 4.26

Fig. 5.1 Fig. 5.2

Fig. 5.3

Fig. 5.4

Fig. 5.5 Fig. 5.6 Fig. 5.7

Fig. 5.8

Fig. 5.9

xxxix

Water supply allocation of the optimistic scenario with adaptation for the Abu Dhabi Emirate. (After Dougherty et al. 2009)...................................................... 172 The total water demand for the for the Emirate of Abu Dhabi under optimistic and pessimistic scenarios, compared with the simulated current water demands averaged over the period 2003 through 2005. (After Dougherty et al. 2009)...................................................... 173 Locations of the detailed study of the hydraulic properties of gravel plains, sand dunes and interdune areas within the Al Ain Region of the Abu Dhabi Emirate.............................. 178 Locations of sand samples collected for grain-size analysis (open circles), and locations of infiltration measurements (black triangles), within the Al Ain Region of the Abu Dhabi Emirate........................................................... 179 Contour map showing lines of equal water surplus (in mm), in the Al Ain area during February 1976. Contour line zero connects points of equal rainfall and evapotranspiration. The shaded area suffers from a water deficit. (After Rizk et al. 1998)............................................................... 180 Contour map showing lines of equal water surplus (in mm) in the Al Ain area during February 1982. Contour line zero connects points of equal rainfall and evaporation. The shaded area suffers from a water deficit. (After Rizk et al. 1998)....................................... 180 Contour map showing lines of equal water surplus (in mm) in the Al Ain area during March 1982. (After Rizk et al. 1998)............................................................... 181 Contour map showing lines of equal water surplus (in mm), in the Al Ain area during February 1988. (After Rizk et al. 1998)............................................................... 181 Curved line represent depths to groundwater in shallow water wells north of Al Ain City, in meters, and columns represent mean annual rainfall (in mm), north of the Al Ain area during the period 1981–1991. (After Rizk et al. 1998)............................................................... 182 Calculation of groundwater recharge, in meters, in the Quaternary aquifer at Al Ain in the Eastern Region of the Abu Dhabi Emirate, with the use of hydrographs of shallow water wells. (After Rizk et al. 1998)............................................................... 183 Mean annual rainfall (in mm) versus groundwater recharge (mm/year) relationship for the Quaternary aquifer in the Al Ain area in the Eastern Region of the Abu Dhabi Emirate. (After Rizk et al. 1998)................................................. 184

xl

Fig. 5.10 Fig. 5.11

Fig. 5.12

Fig. 6.1

Fig. 6.2

Fig. 6.3

Fig. 6.4 Fig. 6.5

Fig. 6.6 Fig. 6.7 Fig. 6.8

Fig. 6.9

List of Figures

Results of grain size analysis of gravel and sand samples from the Al Ain Region of the Abu Dhabi Emirate. (After Rizk et al. 1998)............................................................... 185 Results of infiltration test experiments in gravel plains, sand dunes and interdune areas in the Al Ain Region of the Abu Dhabi Emirate. Sampling locations are illustrated on Fig. 5.2. (After Rizk et al. 1998)............................................ 187 Comparison of hydraulic conductivities of gravel and sand samples from the Quaternary aquifer in the Al Ain Region of Abu Dhabi, calculated with Hazen method (a), field measurements (b) and laboratory analyses (c). (After Rizk et al. 1998)............................................................... 190 The major drainage basins in northern United Arab Emirates and their catchment areas, based on data from the Ministry of Climate Change and Environment. (After Alsharhan et al. 2001; Rizk and Alsharhan 2003)............ 198 The main drainage basins in the northeastern mountain ranges in the United Arab Emirates, traced from topographic maps and Landsat Satellite images. (After Alsharhan et al. 2001; Rizk and Alsharhan 2003)............ 201 Dry drainage basins in the eastern mountain ranges and Jabal Hafit, separated by the Al Jaww plain in the Al Ain area, Eastern Region of the United Arab Emirates. (After Rizk et al. 1998; Rizk and Alsharhan 2003)..................... 202 Contour map of rainfall intensity (in mm), in the eastern mountain ranges of the United Arab Emirates in 1979. (After Rizk et al. 1998)................................................. 206 Contour map of annual runoff volume (Mm3) in the main drainage basins in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998)............................................................... 207 Contour map of runoff depth, in millimeters, in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998).................... 207 Contour map showing the percentage of rainfall as runoff in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998).................... 208 Relationship between annual rainfall (mm) and runoff depth (mm) for five drainage basins in the eastern mountains of the United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)............................................................... 208 Relationship between annual rainfall (mm) and runoff volume (Mm3) in Wadi Al Shaikh in the eastern mountains

List of Figures

Fig. 6.10

Fig. 6.11

Fig. 6.12

Fig. 6.13 Fig. 6.14 Fig. 6.15 Fig. 6.16 Fig. 6.17 Fig. 6.18 Fig. 6.19 Fig. 6.20 Fig. 6.21 Fig. 6.22

xli

of the United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)............................................................... 209 Relationship between runoff volume (Mm3) and basin area (km2) for five drainage basins in the eastern mountains of United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)............................................................... 209 Relationship between annual rainfall (mm) and runoff volume (Mm3) in Wadi Sfini in the eastern mountains of United Arab Emirates during the period 1981–1991. (After Rizk et al. 1998)............................................................... 210 Relationship between the mean annual rainfall (mm) and runoff volume (Mm3) in Wadi Sfini in the eastern mountains of the United Arab Emirates during the period 1981–1991. (After Rizk et al. 1998)............................................................... 210 Relationship between the mean annual rainfall (mm) and runoff volume (Mm3) in Wadi Shik in central UAE for the period 1981–1991. (After Rizk et al. 1998).................... 211 Model-calculated runoff (mm) versus rainfall depth (mm) for (a) Wadi Ham, (b) Wadi Tawiyean and (c) Wadi Al Bih in northern UAE. (After Sherif et al. 2011)................................ 214 Model-­calculated rainfall-storage relationship for (a) Wadi Ham, (b), Wadi Tawiyean and (c) Wadi Al Bih in the northern part of the UAE. (After Sherif et al. 2011)......... 215 Direct runoff-duration–intensity curve for (a) Wadi Ham, (b) Wadi Tawiyean and (c) Wadi Al Bih in the northern part of the UAE. (After Sharif et al. 2011)......................................... 216 Ranking of the flash-flood hazard in various drainage basins of the eastern mountain ranges and Jabal Hafit, according to infiltration capacity. (After Rizk et al. 1998).......................... 219 Theoretical surface runoff hydrographs, according to bifurcation ration (Rb). (Modified by Patton (1988) after Strahler (1964))................................................................... 220 Ranking of flash-flood hazard in various drainage basins of the eastern mountain ranges and Jabal Hafit, according to their bifurcation ratios (Rb). (After Rizk et al. 1998)............. 221 Volumes of runoff water (Mm3) retained by groundwaterrecharge dams in the United Arab Emirates during the period 1983–2005.................................................................. 222 Fluctuations of groundwater levels, measured in observation wells behind main recharge dams in the United Arab Emirates, during the period 1992–2005....... 223 Minimum, average and maximum annual runoff volumes in main drainage basins in northeastern UAE for the period 1992–2005................................................................................... 223

xlii

Fig. 6.23 Fig. 6.24 Fig. 6.25 Fig. 6.26

Fig. 7.1 Fig. 7.2 Fig. 7.3 Fig. 7.4 Fig. 7.5 Fig. 7.6 Fig. 7.7

Fig. 7.8

Fig. 7.9

Fig. 7.10

List of Figures

The areas (km2) and annual runoff volumes (Mm3) in main drainage basins in the UAE, during the period 1981–2005...................................................... 228 Volumes of runoff water (Mm3), stored behind main dams in Eastern and Central Regions of the United Arab Emirates during the period 2001–2005...................................................... 228 Ranking of runoff volumes (Mm3), stored by 21 dams in the Eastern and Central Regions of the United Arab Emirates During the period 2001–2005...................................... 229 Total volumes of runoff water stored by 22 major dams in the Eastern and Central Regions of the United Arab Emirates during the period 2001–2005....................................... 229 Locations of studied UAE and selected groundwaterobservation wells......................................................................... 233 Relationship of annual spring discharge (Mm3) and annual rainfall records (mm) at the nearest meteorological station. (After Rizk and El-Etr 1997; Alsharhan et al. 2001).................. 239 Relationship of annual discharge of Khatt North spring (Mm3) and annual rainfall (mm) at the closest meteorological station................................................................. 240 Relationship of annual discharge of Khatt South spring (Mm3) and annual rainfall (mm) at the closest meteorological station................................................................. 240 Rainfall impacts on the groundwater table and variations of springs flows. (After Mohamed et al. 2016)........................... 241 Relationship of spring discharge (Mm3) and groundwater depth (m) in the nearest groundwater observation wells. (After Rizk and El-Etr 1997; Alsharhan et al. 2001).................. 242 Diagram explaining the variation in temperature, salinity and hypothetical dissolved salts in spring waters of the UAE (after Rizk and El-Etr 1997; Alsharhan et al. 2001; Rizk and Alsharhan 2003; Rizk and Alsharhan 2008)......................... 243 Groundwater systems of flow in the UAE and their influence on water type and salinity of natural permanent springs (after Rizk and El-Etr 1997; Alsharhan et al. 2001; Rizk and Alsharhan 2003)........................................................... 243 Presentation of chemical analysis of the year 1991 for permanent UAE springs BS = Bu, SJ = Maddab, KN = Khatt North and KS = Khatt South. (Rizk and El-Etr 1997)................................................................ 247 Presentation of chemical analysis of the year 1994 for permanent UAE springs BS = Bu, SJ = Maddab, KN = Khatt North and KS = Khatt South; Rizk and El-Etr 1997)................................................................. 248

List of Figures

Fig. 7.11 Fig. 7.12 Fig. 7.13 Fig. 7.14 Fig. 7.15

Fig. 8.1 Fig. 8.2

Fig. 8.3 Fig. 8.4 Fig. 8.5 Fig. 8.6 Fig. 8.7

Fig. 8.8 Fig. 8.9

xliii

Comparison of water chemistry in Khatt North (KN) spring at Ras Al Khaimah and groundwater chemistry in surrounding wells. (After Rizk and El-Etr 1997)............................................ 249 Comparison of water chemistry in Khatt South (KS) spring in the Ras Al Khaimah area and groundwater chemistry in surrounding wells. (After Rizk and El-Etr 1997).................... 250 Comparison of water chemistry in Maddab Spring (SJ) in the Fujairah area and groundwater chemistry in surrounding wells. (After Rizk and El-Etr 1997).................... 251 Comparison of water chemistry in Ain Al Faydah Spring (BS) in the Al Ain area and groundwater chemistry in surrounding wells (after Rizk and El-Etr 1997)...................... 252 Evaluation of the suitability of groundwater of permanent springs in the UAE and surrounding groundwater for irrigation, according to electrical conductivity (EC in μS/cm) and Sodium Adsorption Ratio (SAR). (After Rizk and El-Etr 1997)...................................................... 253 (a) Map view and cross section in one of Aflaj Al Daudi in the UAE (Rizk 1998), and (b) a typical cross section in the Qanat................................................................................. 259 Simplified geomorphologic map of eastern and northeastern UAE, showing the Iron Age aflaj systems in the Al Ain and Al Madam areas. (Based on data from the UAE National Atlas 1993; Rizk and Alsharhan 2008; Al Tikriti 2015)............. 261 Locations, directions and discharge areas of the aflaj systems in the eastern UAE. (After Rizk 1998; Alsharhan et al. 2001)................................................................. 266 Stable isotopes (2H and18O) in water samples from the gravel aquifer and Aflaj Al Daudi in Al Ain area, UAE (after Rizk and Alsharhan 1999)........................................ 269 Hydrographs aflaj systems in the Al Ain area for the period 1964–1996, based on data from various sources. (After Rizk 1998; Rizk and Alsharhan 2003)............... 270 Discharge of United Arab Emirates remaining aflaj in 2006 and 2007. (After Rizk and Alsharhan 2008).................. 271 (a) Change in groundwater level in Al Ain over the last 4500 years (EAD 2006); and (b) groundwater depth (m) in the western gravel aquifer in the Al Ain area in February 1995. (After Garamoon 1996)................................. 273 Iso-electrical conductivity (μS/cm) and isosalinity (mg/L) contour lines of aflaj water and groundwater in eastern UAE. (After Rizk 1998; Rizk and Alsharhan 2003)............................. 274 Relationship between length (m) and EC (μS/cm) in aflaj Al Gheli (a), and aflaj Al Daudi (b), in the eastern

xliv

Fig. 8.10 Fig. 8.11

Fig. 9.1 Fig. 9.2 Fig. 9.3 Fig. 9.4

Fig. 9.5 Fig. 9.6 Fig. 9.7

Fig. 9.8

Fig. 9.9 Fig. 9.10

List of Figures

and northeastern UAE. (After Rizk 1998; Rizk and Alsharhan 2003)................................................................... 276 Presentation of chemical analysis of aflaj water in the eastern and northeastern UAE on the trilinear diagram. (After Rizk 1998; Rizk and Alsharhan 2003)............................. 277 Diagram illustrating the suitability of aflaj water for irrigation in the UAE, on the basis of SAR and EC (μS/cm) values. See Table 8.1 for aflaj names. (After Rizk 1998; Rizk and Alsharhan 2003; Rizk and Alsharhan 2008)........................................................... 278 Location of Ras Al Khaimah area, the Wadi Al Bih basin and water wells sampled for study of the Wadi Al Bih limestone aquifer......................................................................... 283 Simplified geologic map of Wadi Al Bih and surrounding areas, Ras Al Khaimah Emirate.................................................. 284 Water-table contour map for Wadi Al Bih limestone aquifer. (Alsharhan et al. 2001; Rizk et al. 2007).................................... 286 Contour map of groundwater temperature (°C) in the Wadi Al Bih limestone aquifer during April and September of 1996, Ras Al Khaimah Emirate. (Alsharhan et al. 2001; Rizk et al. 2007).................................... 291 Iso-salinity contour map, in milligrams per liter, for the Wadi Al Bih limestone aquifer in April and September of 1996. (After Alsharhan et al. 2001; Rizk et al. 2007)............. 291 Average chloride-ion content in the Wadi Al Bih limestone aquifer for the period 1980–1994. (After Alsharhan et al. 2001; and Rizk et al. 2007)................................................................... 293 Presentation of selected ions (a) K versus Na, (b) Cl versus Na, (c) SO4 versus Cl, and (d) Mg versus Ca, proves the absence of a relationship between groundwater and seawater in the Wadi Al Bih limestone aquifer. (After Rizk et al. 2007)............................................................... 294 Relationship of stable isotopes of hydrogen (2H) and oxygen (18O) for the global rainwater line, local rainwater line and groundwater in the Wadi Al Bih limestone aquifer, Ras Al Khaimah Emirate. (After Rizk et al. 2007)..................... 295 Plot of tritium (3H), in tritium units (TU), versus chloride-ion concentration (in mm/L) in the Wadi Al Bih limestone aquifer in 1996. (After Rizk et al. 2007)................................................. 295 Presentation of the results of chemical analyses of water from the Wadi Al Bih limestone aquifer in 1996, on Piper’s diagram. (After Rizk et al. 2007)............................... 299

List of Figures

Fig. 9.11 Fig. 9.12

Fig. 9.13

Fig. 10.1 Fig. 10.2 Fig. 10.3 Fig. 10.4

Fig. 10.5

Fig. 10.6 Fig. 10.7

Fig. 10.8 Fig. 10.9

Fig. 10.10

xlv

Schematic cross section illustrating the hydrogeologic conditions of the Wadi Al Bih limestone aquifer. (After Rizk et al. 2007)............................................................... 300 Cross section in Jabal Hafit, south of Al Ain City, illustrating a hypothetical model for recharge and discharge of the Dammam limestone aquifer. (Modified after Khalifa 1997).............................................................................. 303 Schematic cross section showing injection of saline groundwater in oil-producing layers, and disposal of wastewater in a clastic aquifer in the Western Region of the Abu Dhabi Emirate. (After Al Amari 1997)...................... 306 Location of the Al Dhaid Super Basin. (After Rizk and Garamoon 2006)............................................... 313 Geomorphologic map of the eastern UAE, where the ophiolite aquifer constitutes almost one half of the rock outcrops. (After Rizk and Garamoon 2006)............. 314 Al Dhaid Super Basin and its five sub-basins, as drawn with the use of topographic maps of different scales. (After Rizk and Garamoon 2006)............................................... 316 Dominant drainage patterns in the Al Dhaid Super Basin and the relationship between stream numbers and stream order in its five sub-basins. (After Rizk and Garamoon 2006)............................................... 318 Analysis of linear features in the Al Dhaid Super Basin, based on the main drainage lines and major linear trends in the Northern Oman Mountains (a), and the western gravel plain (b) (after Rizk and Garamoon 2006)......... 319 Map showing the fractures, folds and faults affecting the ophiolite aquifer in the eastern UAE, based on lineaments analysis. (After Rizk and Garamoon 2006)................................ 320 Contour map showing density of intersection of major linear trends in the Al Dhaid Super Basin, based on the analysis of drainage basins and their relation to major linear trends................................................................................. 322 Geologic map for eastern UAE. (After Rizk and Garamoon 2006)................................................................... 325 Map illustration the major faults in the Al Dhaid Super Basin, based on analysis of anomalies in the Earth’s gravitational field. (After Al Asam 1998; Rizk and Alsharhan 2003)........................................................... 327 Hydraulic heads in m in the Al Dhaid area in 1985 (a) and 1998 (b) and the decline in hydraulic heads between 1985 and 1998 (c)......................................................... 328

xlvi

Fig. 10.11 Fig. 10.12 Fig. 10.13

Fig. 11.1

Fig. 11.2 Fig. 11.3 Fig. 11.4 Fig. 11.5 Fig. 11.6 Fig. 11.7

Fig. 11.8 Fig. 11.9

List of Figures

Contour maps of groundwater temperature (°C), and the effect of Wadi Ham Line on groundwater level (m amsl) in the Al Dhaid Super Basin, the eastern UAE............ 329 Presentation of chemical analysis of water samples from the ophiolite aquifer in the eastern UAE on the trilinear plot. (After Rizk and Garamoon 2006)............... 331 (a) Contour map of electrical conductivity (μS/cm), (b) magnesium-ion concentration (mg/L), and (c) bicarbonate ion concentration (mg/L), showing the influence of the Wadi Ham line on the Al Dhaid Super Basin. (After Rizk and Garamoon 2006)............................................... 332 Simplified geologic map of the Eastern Region of UAE, showing the eastern coastal plain and rock outcrops belonging to the Ru’us Al Jibal carbonates and Semail ophiolite sequence....................................................................... 339 Map for the Fujairah area showing water wells used for investigation of the hydrogeology of the eastern gravel aquifer............................................................................... 340 Cross section showing the thickness (m) and groundwater table (m amsl) of the eastern gravel aquifer in the Fujairah area along the eastern coastal plain of the UAE.......................... 341 Cross section sowing the main hydrogeologic units and groundwater level (m amsl) in the Wadi Dibba area, Eastern Region of the UAE......................................................... 342 Topographic map of Wadi Dibba showing shallow and deep water wells and a trace of the hydrogeologic cross section illustrated on Fig. 11.4........................................... 343 Hydrogeologic map showing topographic elevations (m), and groundwater levels (m amsl) in the eastern gravel aquifer in Wadi Dibba, eastern UAE....................................................... 344 Top: a conventional four electrode array to measure the subsurface resistivity, a–d: common arrays used in resistivity surveys and their geometric factors. Bottom: the arrangement of electrodes for a 2D electrical survey and the sequence of measurements used to build up a pseudo section. (After Loke 1997)....................................................................... 345 Drainage basins subject of geoelectrical investigations in Wadis of Tawiyean, Basserah and Wurrayah, eastern UAE................................................................................ 346 2D earth-resistivity profiles in Wadi Al Ruheib (top left), Wadi Dadna (top right), Wadi Al Basserah (middle left), Wadi Al Wurrayah (middle right and lower left), and Wadi Al Tawiyean (lower right). (Compiled from Ebraheem et al. 1990)...................................... 347

List of Figures

Fig. 11.10 Fig. 11.11 Fig. 11.12 Fig. 11.13 Fig. 11.14 Fig. 11.15 Fig. 11.16

Fig. 11.17 Fig. 11.18 Fig. 11.19 Fig. 11.20 Fig. 11.21

Fig. 11.22 Fig. 11.23 Fig. 11.24

xlvii

2D DC-resistivity data and modeling for profile Al-Ruheib-1 and Al Ruheib-2, Eastern Region of the UAE. (See Fig. 11.9 for profile location).............................................. 348 2D DC-resistivity data and modeling for profile Al-Ruheib-3, Eastern Region of the UAE (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)..................... 349 2D DC-resistivity data and modeling for profiles Dadnah-1 and Dadnah-3, Eastern Region of the UAE (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)..................... 350 2D DC-resistivity data and modeling for profiles Dadnah-4 and Dadnah-5, Eastern Region of the UAE (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)..................... 351 2D DC-resistivity data and modeling for profiles Al Basserah-1 and Al Basserah-2 (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)....................................................... 352 2D DC-resistivity data and modeling for profiles Al Basserah-3 and Al Basserah-4 (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)..................... 353 Two-dimensional DC-resistivity models for profiles Wurrayah-1 to Wurrayah-4 in Wadi Al Wurrayah (See Fig. 11.9 for profile location). (After Ebraheem et al. 2015)....................................................... 354 2D DC-resistivity models for profiles in Wadi Al Tawiyean (See Fig. 11.9 for profiles location). (After Ebraheem et al. 2015)....................................................... 356 Open circles represent the locations of water wells sampled for hydrochemical analysis of the eastern gravel aquifer............ 357 Contour map showing isosalinity lines (mg/L) in the Eastern Region of the UAE, including the eastern gravel aquifer............................................................ 358 Contour map showing isosalinity lines (mg/L) in groundwater of Wadi Dibba, the northeastern UAE............... 359 Inverse relationship between the mean annual rainfall (mm) and the TDS contents (mg/L) in the eastern gravel aquifer along the eastern coastal plain of the United Arab Emirates........................................................ 360 Presentation of the chemical analysis of groundwater in the eastern gravel aquifer on the trilinear diagram.................. 361 Recurrence distribution of the hydrogen radioisotope tritium (TU), in the eastern gravel aquifer in the UAE............... 362 Map illustrating the groundwater suitability, in the eastern gravel aquifer in the UAE, for irrigation, based on the calculated values of sodium adsorption ratio (SAR)........ 363

xlviii

Fig. 11.25 Fig. 11.26 Fig. 11.27 Fig. 11.28 Fig. 11.29 Fig. 11.30

Fig. 11.31 Fig. 11.32 Fig. 11.33 Fig. 11.34 Fig. 11.35

Fig. 11.36

Fig. 11.37

Fig. 11.38

List of Figures

Graph illustrating the suitability of groundwater in the eastern gravel aquifer for irrigation purposes, based EC (μS/cm) and SAR........................................................ 364 Location of the Al Ain area, eastern UAE, where a detailed study was conducted on the western gravel aquifer...... 365 Groundwater depth (m) in the western gravel aquifer in the Al Ain area, in February 1995........................................... 367 Base of the upper layer of the western gravel aquifer, in m below the ground surface, based on results of well logs in the Al Ain area........................................................................ 368 Contour map showing equipotential lines of the western gravel aquifer, in m amsl, based on field investigations and well logs in the Al Ain area.................................................. 369 Locations of groundwater samples collected for hydrochemical study of the western gravel aquifer in the Al Ain area. N–S, E–W and NE–SW are traces of hydrochemical profiles, illustrated on Figs. 11.38, 11.39 and 11.40. (After Garamoon 1996; Rizk et al. 1998)................. 371 Contour map showing iso-electrical conductivity contour lines (μS/cm) of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)............... 373 Iso-salinity contour lines (mg/L) for the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)...................... 374 Contour maps showing the distribution of cations contour lines of the western gravel aquifer in Al Ain area. (After Garamoon 1996; Rizk et al. 1998)................................... 376 Contour maps showing the distribution of anion-contour lines of the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998).......................................................................... 377 Presentation of the chemical analysis of water in the western gravel aquifer in the Al Ain area, on a Piper’s diagram, performed in May 1994. (After Garamoon 1996; Rizk et al. 1998).......................................................................... 378 Presentation of the chemical analysis of water in the western gravel aquifer in the Al Ain area, on a Piper’s diagram, performed in February 1995. (After Garamoon 1996; Rizk et al. 1998)................................... 379 Classification of groundwater in the western gravel aquifer in the Al Ain area, based on its contents of hypothetical water-dissolved salts and results of presentation of chemical analysis of groundwater on a Piper’s diagram. (After Garamoon 1996; Rizk et al. 1998)................................... 380 Northeast–southwest hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)................................... 381

List of Figures

Fig. 11.39 Fig. 11.40 Fig. 11.41 Fig. 11.42 Fig. 11.43 Fig. 11.44 Fig. 11.45 Fig. 11.46

Fig. 11.47

Fig. 11.48 Fig. 11.49

Fig. 12.1

Fig. 12.2

xlix

North–south hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)................................... 382 East–west hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998).......................................................................... 383 Coincidence of areas of intensive agricultural activities with areas of nitrate pollution in the United Arab Emirates. (After Rizk 2014)........................................................................ 383 Contour maps showing iso-contour lines of nitrate and phosphate in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)................................... 384 Contour maps showing iso-contour lines of fluoride ion, strontium, iron and manganese in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)...................... 385 Contour maps showing iso-contour lines of copper, lead, zinc and chromium in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)................................... 386 Locations of sampling for isotopes analysis, including the western gravel aquifer in the Al Ain area. (After Rizk et al. 1998; Rizk and Alsharhan 2003)..................... 387 Stable isotopes hydrogen (2H‰) and oxygen (18O‰) water of the UAE, including the western gravel aquifer in the Al Ain area. (After Rizk et al. 1998; Rizk and Alsharhan 2003)................................................................... 387 Classification of groundwater in the western gravel aquifer in the Al Ain area, based on TDS (mg/L), total hardness (mg/L), sodium adsorption ratio (SAR) and suitability for irrigation. (After Garamoon 1996; Rizk et al. 1998).......................................................................... 388 Suitability of water in the western gravel aquifer in the Al Ain area for irrigation in the eastern UAE during June 1994. (After Garamoon 1996)........................ 389 Suitability of water in the western gravel aquifer in the Al Ain area for irrigation in the eastern UAE during February 1995. (After Garamoon 1996)................. 390 Roads, main cities and water wells used for investigating the sand aquifer at Liwa Oasis and Bu Hasa areas, in the western UAE. A-A’ is the trace of the geologic cross section illustrated in Fig. 12.2............................................ 397 Lithologic cross section in the Liwa Oasis and Bu Hasa oil field in the western UAE (including the Liwa Quaternary sand aquifer). (After Imes et al. 1994)........................................ 398

l

Fig. 12.3 Fig. 12.4a

Fig. 12.4b Fig. 12.5

Fig. 12.6

Fig. 12.7

Fig. 12.8

Fig. 12.9 Fig. 12.10 Fig. 12.11 Fig. 12.12 Fig. 12.13 Fig. 12.14 Fig. 12.15

List of Figures

Results of analyses of grain-size distribution of sediment samples from Liwa aquifer sand in Liwa Oasis, Western Region of Abu Dhabi Emirate. (After Wood et al. 2003)............ 401 Major landforms in the Liwa area. Contour map of equal saturated thicknesses of the Liwa aquifer, in m. Open and closed circles represent data points. (After Wood et al. 2003; Rizk 2014)........................................... 402 Hydraulic-head contour map of the Liwa aquifer, in m amsl. Arrow-headed lines indicate groundwater-flow paths. (After Wood et al. 2003)............................................................. 403 Schematic diagram illustration recharge and discharge of groundwater in the Liwa aquifer and the internal sabkha area at the Liwa oasis, western UAE. (After Wood et al. 2003)............................................................. 406 North–south sketch diagram showing the groundwater flow directions in the groundwater mound in the Liwa Quaternary aquifer in the western UAE. (After Wood et al. 2003)............................................................. 406 Contour map showing the isosalinity lines (mg/L) in the Liwa aquifer in the Liwa area, western UAE for the years 1964 (solid lines) to 1996 (dashed lines). (After Al Amari 1997)................................................................. 407 Evolution of groundwater salinity (mg/L) in the Liwa Quaternary sand aquifer, along a NW–SE cross section across the Bu Hasa oil field, Western Region of the Abu Dhabi Emirate, during the period 1964–1996. (After Al Amari 1997)................................................................. 408 Isosalinity contour lines (mg/L), showing the Liwa aquifer, western UAE. (After Wood et al. 2003)...................................... 409 Iso-concentration contour lines of Ca2+ and Mg2+ (mg/L) in the Liwa aquifer in the western UAE. (After Wood et al. 2003)............................................................. 410 Iso-concentration contour lines of sodium and K+ (mg/L) in the Liwa aquifer, western UAE. (After Wood et al. 2003)...... 411 Iso-concentration contour lines of HCO3− and SO42− ions (mg/L) in the Liwa aquifer, western UAE. (After Wood et al. 2003)............................................................. 412 Iso-concentration contour lines of Cl− and NO3− (mg/L) in the Liwa aquifer, western UAE. (After Wood et al. 2003)...... 413 Contour maps showing the iso-concentration lines of F− and Cr (mg/L) in the Liwa aquifer, western UAE. (After Wood et al. 2003)............................................................. 417 Contour maps showing the iso-concentration lines of B and Zn (mg/L) in the Liwa aquifer, western UAE. (After Wood et al. 2003)............................................................. 418

List of Figures

Fig. 12.16 Fig. 12.17

Fig. 13.1 Fig. 13.2

Fig. 13.3

Fig. 13.4

Fig. 13.5

Fig. 13.6 Fig. 13.7

Fig. 13.8

Fig. 13.9

li

Presentation of the results of chemical analysis of the Liwa aquifer at the Liwa oasis (a) and Bu Hasa oil field (b), western UAE, on trilinear diagram. (After Wood et al. 2003).... 419 Plot of the stable isotopes of oxygen (18O‰) and hydrogen (2H‰) values in the Liwa aquifer, compared to the Eastern Mediterranean meteoric water line and rain values in Bahrain and Sultanate of Oman. (After Wood et al. 2003)..... 423 Locations of water wells used for study of hydrochemistry and isotope hydrology of the sand and gravel aquifer. (After Alsharhan et al. 2001)....................................................... 429 Contour map showing lines of equal groundwater depth, in meters below the ground surface, in the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 430 Contour map showing lines of equal hydraulic head, in meters above mean sea level, of groundwater in the sand and gravel aquifer system in the UAE, arrow-headed lines indicate directions of groundwater flow. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 431 Contour map illustrating lines of equal temperature, in degree Celsius, of groundwater in the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001) ................................................................ 433 Contour map showing lines of equal electrical conductivity, in microsiemens per centimetre, of groundwater in the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 434 Contour map showing lines of equal hydrogen ion concentration of groundwater the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001).............. 434 Contour map showing lines of equal concentration of calcium ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 435 Contour map showing lines of equal concentration of magnesium ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 436 Contour map showing lines of equal concentration of sodium ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 436

lii

Fig. 13.10

Fig. 13.11

Fig. 13.12

Fig. 13.13

Fig. 13.14

Fig. 13.15

Fig. 13.16

Fig. 13.17

Fig. 13.18

Fig. 13.19

Fig. 13.20

List of Figures

Contour map showing lines of equal concentration of potassium ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 437 Contour map showing lines of equal concentration of bicarbonate ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 438 Contour map showing lines of equal concentration of sulphate ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 439 Contour map showing lines of equal concentration of chloride ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 440 Contour map showing lines of equal concentration of nitrate ion, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 441 Map illustrating the coincidence between agricultural areas and areas of high nitrate ion (mg/L) concentration in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 442 Contour map showing lines of equal percentages of calculated calcium bicarbonate dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 442 Contour map showing lines of equal percentages of calculated magnesium bicarbonate dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 443 Contour map showing lines of equal percentages of calculated calcium sulphate dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 443 Contour map showing lines of equal percentages of calculated sodium sulphate dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 444 Contour map showing lines of equal percentages of calculated magnesium chloride dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 444

List of Figures

Fig. 13.21

Fig. 13.22 Fig. 13.23 Fig. 13.24 Fig. 13.25 Fig. 13.26

Fig. 13.27

Fig. 13.28 Fig. 13.29 Fig. 13.30 Fig. 13.31

Fig. 14.1 Fig. 14.2 Fig. 14.3

liii

Contour map showing lines of equal percentages of calculated sodium chloride dissolved salt in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 445 Map showing the distribution of calcium/magnesium ratio in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 445 Map showing the distribution of sulphate/chloride ratio in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 446 Map showing the distribution of chloride/(carbonate+bicarbonate) ratio in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 446 Map showing the distribution of sodium/chloride ratio in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 447 Contour map showing lines of equal total hardness, in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 447 Contour map showing lines of equal sodium adsorption ratio (SAR), in milligrams per liter, in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)................................................................. 448 Map showing distribution of the stable isotope oxygen-18 (18O) in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 448 Map showing distribution of the stable isotope deuterium (2H) in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 449 Map showing distribution of the radioisotope tritium (3H) in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 449 Map showing distribution of the radioisotope carbon-14 (14C) in groundwater of the sand and gravel aquifer system. (After Rizk et al. 1997; Alsharhan et al. 2001)........................... 450 The amounts and sources of water used by various sectors in the UAE in 2008. (After MOEW 2010).................................. 456 Main coastal desalinated plants (shaded circles) and inland desalination plants (open circles) in the UAE. (After Al Asam and Rizk 2009)........................................ 458 Cross-sectional area in a salinity gradient solar pond, illustrating different layers and temperature profiles. (After Al Asam and Rizk 2009).................................................. 467

liv

Fig. 15.1 Fig. 15.2 Fig. 15.3 Fig. 15.4 Fig. 15.5 Fig. 15.6 Fig. 15.7 Fig. 16.1

Fig. 16.2 Fig. 16.3

Fig. 16.4 Fig. 16.5 Fig. 16.6 Fig. 16.7 Fig. 16.8 Fig. 16.9

List of Figures

Produced wastewater projections in the UAE. (After Al Asam and Rizk 2009).................................................. 473 Percentage of reused sewage effluent to produced effluents in the UAE in 2010. (Based on data from the MOEW).............. 473 Treated wastewater production during the period 2011–2015 (in Mm3/year).............................................................................. 474 Predicted quantities of produced wastewater in the UAE during the period 2007–2020 (in Mm3). (After MOEW 2010)................................................................... 475 Sewage and onsite coverage in the UAE in 2008. (After MOEW 2010)................................................................... 476 Map showing locations of major desalination plants in the United Arab Emirates. (Based on data compiled from various sources).................................................................. 477 Most common types of bacteria found in the BSA media. (After Al Amimi et al. 2014)....................................................... 481 Iso-potential contours in the western gravel aquifer of the Al Shuaib area, Al Ain Region of Abu Dhabi Emirate in 1992 (a) and 2002 (b), and the difference between the 2 years (c). (After Al Hammadi 2003).................................. 506 Decline of groundwater level of the western gravel aquifer around the Al Hamraniyah area, Ras Al Khaimah Emirate. (After MOEW 2015).................................................... 507 Water-logging problem west of the Al Ain area: (a) WD (groundwater depth in m), (b) TDS (groundwater salinity in mg/L), (c) Cl− (chloride ion concentration in mg/L), and (d) SO42− (sulphate ion concentration in mg/L). (After Murad et al. 2014)............................................................ 508 Location of the Dibdibba water-well field, Ajman Emirate, United Arab Emirates. (After Al-Hogaraty et al. 2008).............. 511 Graph showing the increase in concentration of TDS, mg/L, in observation wells in the Emirate of Ajman during the period 1981–2005................................................................................... 511 Location of the Al Burayrat water-well field, Ras Al Khaimah Emirate............................................................. 512 Graph showing the increase in concentration of TDS, mg/L, in observation wells in the Emirate of Ras Al Khaimah during the period 1981–2005................................. 512 Location of water-well fields in Sharjah Emirate. (Data from Sharjah Electricity and Water Authority; SEWA)....................................................................... 513 Graph showing the increase in concentration of TDS, mg/L, in observation wells in the Emirate of Sharjah during the period 1981–2005.................................................................. 513

List of Figures

Fig. 16.10 Fig. 16.11 Fig. 16.12

Fig. 16.13 Fig. 16.14 Fig. 16.15 Fig. 18.1

Fig. 18.2

Fig. 18.3

Fig. 18.4 Fig. 18.5 Fig. 18.6

Fig. 18.7

lv

Graph showing the increase in concentration of TDS, mg/L, in observation wells in the Emirate of Fujairah during the period 1981–2005...................................................... 514 Graph illustration increasing concentration of TDS, mg/L, in observation wells in the northern emirates during the period 1981–2005.................................................................. 515 (a) Iso-concentration (mg/L) contour map of measured Na+ concentration, and (b) calculated sodium sulphate salt Na2(SO4) in groundwater of the Quaternary aquifer within Umm Al Quwain Emirate in April 2008 (solid lines) and May 2009 (dashed lines)...................................................... 519 Groundwater reverse-osmosis (GWRO) inland desalination plants in eastern UAE. (After Mohemed et al. 2005).................. 521 Evolution of water GWRO and reject-brine production during the period 1995–2001 in the Al Ain Region of Abu Dhabi Emirate. (After Mohemed et al. 2005)................. 522 Total petroleum hydrocarbons concentration, in parts per billion (ppb), in sediment samples from the Arabian Gulf... 523 Maps and an aerial image showing the location of the United Arab Emirates (a), the Wadi Al Bih area (b), and sampling locations (c). Black and open circles in Fig. 1c indicate the sampled sites during November 2014 and June 2015..................................................................... 551 Satellite image illustrating the Jabal Hafit and Neima areas, Al Ain City. Other maps show the location of the UAE and locations of water wells sampled for this study. (After Murad et al. 2011)............................................................ 556 Graph showing the TDS–strontium relationship, illustrating the three processes affecting the Dammam limestone aquifer in the Al Ain area [dilution (B), contamination (C) and salinization (A)]. (After Murad et al. 2011)......................... 557 The ophiolite aquifer in the UAE and Oman. The red lines are the main geologic structures affecting the area. (After Etiope et al. 2015)............................................................ 558 The δ2HCH4 and δ13CCH4 composition of methane in the Al Farfar well tapping the Semail ophiolite aquifer. (After Etiope et al. 2015)............................................................ 559 Schematic diagram showing possible migration of abiotic methane from serpentinized peridotites into natural gas fields in a large sedimentary basin. (After Etiope et al. 2015)............................................................ 560 Satellite images of the Wadi Ham area, showing the modeling area, Wadi Ham dam and ponding area,

lvi

Fig. 18.8 Fig. 18.9

Fig. 18.10 Fig. 18.11 Fig. 18.12

Fig. 18.13

Fig. 18.14

Fig. 18.15 Fig. 18.16

Fig. 18.17 Fig. 18.18 Fig. 18.19

List of Figures

ophiolite outcrop, water-well fields and sampled water wells. (After Sherif et al. 2014)............................................................. 561 Water-table contour map of the eastern gravel aquifer in the Wadi Ham area in 1988, in m amsl. (After Sherif et al. 2014)............................................................. 562 Initial groundwater salinity (mg/L) distribution used in numerical modeling of the eastern gravel aquifer in the Wadi Ham area, Fujairah Emirate. (After Sherif et al. 2014)............................................................. 563 Simulated groundwater salinity for 2010 in the eastern gravel aquifer of the Wadi Ham area, Fujairah Emirate. (After Sherif et al. 2014)............................................................. 564 Distribution of groundwater salinity in the eastern gravel aquifer of the Wadi Ham area, Fujairah Emirate in 2020, according to scenario-2. (After Sherif et al. 2014)....... 565 Model-calculated groundwater salinity for 2020 under the third scenario in the eastern gravel aquifer of the Wadi Ham area, Fujairah Emirate. (After Sherif et al. 2014)............................................................. 566 Satellite image showing the geography and morphology of the Jabal Hafit area. Red points represent the spatial distribution of groundwater locations. (After Mohamed and Elmahdy 2015)......................................... 567 Iso-salinity map of the western gravel aquifer in the Al Ain area, showing that groundwater samples with the highest groundwater-salinity zones are collected from water wells around in the Jabal Hafit area. (After Mohamed and Elmahdy 2015)......................................... 570 Land-use classification in the Liwa area. (After Rizk 2014)........................................................................ 573 Ternary diagram of anions: (a) (Cl, N-NO3 and SO4); (c) (SO4, Cl and HCO3), and cations: (b) and (d) (Ca, Na + K and Mg), showing: soil water–rain, sewage treatment plant and septic tanks–cesspools, waste water, residential and agriculture fields................................................. 574 Locations map of the study area. (After Al-Hogaraty et al. 2008)................................................... 575 Classification of Land use in Ajman City, based on data from Ajman Municipality and Planning Department, field survey and satellite images............................. 576 Simplified geologic map of the study area. (From Kansas Geological Survey 1990)..................................... 577

List of Figures

Fig. 18.20 Fig. 18.21 Fig. 18.22 Fig. 18.23 Fig. 18.24 Fig. 18.25

Fig. 18.26

Fig. 18.27

Fig. 19.1 Fig. 19.2 Fig. 19.3 Fig. 19.4 Fig. 19.5 Fig. 20.1 Fig. 20.2 Fig. 21.1 Fig. 21.2 Fig. 21.3

lvii

Field-identified point pollution sources affecting the aquifer system in the Ajman area, United Arab Emirates.................................................................. 578 Graph illustrating the monthly values of the climatic elements in Ajman....................................................................... 579 Location of water wells used for hydrogeologic and hydrogeochemical investigations......................................... 580 Groundwater depth (dotted lines) and hydraulic head contours (solid lines)................................................................... 581 Isosalinity contour map of groundwater in the Ajman area. (After Al-Hogaraty et al. 2008............................................ 581 Contour maps of the hydrochemical parameters pH (a), TDS (b), TH (c), DO (d), and concentrations of major cations calcium (e), magnesium (f), sodium (g) and potassium (h) ions in groundwater at Ajman area. The dotted zone suffers from saltwater intrusion........................ 582 Contour maps of the anions bicarbonate (a), sulphate (b), chloride (c) and nitrate (d) ions, in addition to trace elements iron (e), lead (f), cadmium (g) and chromium (h) elements in groundwater of the in the Ajman area. The dotted zone suffers from saltwater intrusion....................................................................... 583 Hydrochemical cross section illustrating the contribution of natural processes and human activities to groundwater pollution............................................................. 585 The percentage contribution of water stored in dam reservoirs to agricultural water demand in the UAE. (After MOEW 2010)................................................................... 596 The effect of agricultural subsidies on farm potentiality and groundwater use. (After MOEW 2010)................................ 697 Farm water use in million m3 per hectare. (After MOEW 2010)................................................................... 698 Evolution of per capita water share in the UAE during the period 2004–2008. (After MOEW 2010).............................. 600 Uncontrolled water imports may lead to increasing water wastage. (After MOEW 2010).......................................... 601 Locations of ASR pilot projects in the Abu Dhabi Emirate........ 626 Locations of ASR pilot project in Nizwa, Sharjah Emirate........ 628 Sectoral water consumption. (After Al Awar 2014).................... 632 Evolution of the number of farms and modern irrigation techniques during the period 1977–1993.................................... 636 Evolution of the number of farms and modern irrigation techniques during the period 1998–2002.................................... 636

lviii

Fig. 21.4 Fig. 21.5 Fig. 21.6 Fig. 21.7 Fig. 21.8 Fig. 21.9 Fig. 21.10 Fig. 21.11 Fig. 21.12 Fig. 21.13

Fig. 22.1 Fig. 22.2

Fig. 22.3 Fig. 22.4 Fig. 22.5 Fig. 22.6

List of Figures

Evolution of the organic production farms during the period 2007–2013. (MOEW 2015)....................................... 636 Evolution of the green lands and areas of forests (in Hectare), during the period 1980–1992................................. 637 Evolution of the green lands and areas of forests during the period 1998–2002...................................................... 638 Comparison of the number of farms in various emirates in the UAE................................................................................... 642 Evolution of the number of farms and modern irrigation techniques during the period 1998–2002.................................... 642 Evolution of the number of greenhouses in Abu Dhabi Emirate during the period 2010–2015. (After SCAD 2016)..................................................................... 645 Distribution, numbers and areas (Dunam) of greenhouses in the UAE in 2005...................................................................... 646 Relationship of crop productivity (%) and electrical conductivity (EC in mS/cm) of irrigation water.......................... 647 Growth of agriculture water demand in the UAE for the period 1990–2010. (After Shahin and Salem 2015)................................................... 650 Evolution of the area of forest plantation in the United Arab Emirates during the period 1990–2015. (After the World Bank 2015)...................................................... 651 Locations of sand samples collected for grain-size analysis (open circles) and sites of infiltration test (black triangles), within Al Ain Region of Abu Dhabi Emirate.............................. 658 Sand dunes and interdune areas in Al Ain, traced from Landsat Satellite images, scale 1:100,0000. The dashed area is the extent of the area of the study. (After Rizk et al. 1998a, b)......................................................... 659 Iso-uniformity coefficient (Cu) contour lines for sand samples from southwest Al Ain Region of Abu Dhabi Emirate. (After Rizk et al. 1998a, b)......................................................... 662 Iso-infiltration rate (Ir in cm/min) contour map for sand dunes in Al Ain Region of Abu Dhabi Emirate. (After Rizk et al. 1998a, b)......................................................... 663 Iso-infiltration rate (Ir in cm/min) contour map for interdune areas around Al Ain City, Eastern Region of Abu Dhabi Emirate (Rizk et al. 1998a, b)............................... 664 Classification of sand-dune areas (C5, C6 and C7), based on uniformity coefficient (Cu), and interdune areas (C1, C2, C3 and C4), based on soil moisture content. (After Rizk et al. 1998a, b)......................................................... 665

List of Figures

Fig. 23.1

Fig. 23.2

Fig. 23.3

Fig. 23.4

Fig. 23.5

Fig. 24.1

Fig. 24.2 Fig. 24.3

Fig. 24.4 Fig. 24.5

Fig. 24.6

lix

Showing locations of the UAE, study area, water wells and observation wells used for construction of the GIS a model for the study area. AA’ is the trace of the geologic cross section illustrated on Fig. 23.4.................. 671 Southeast–northwest geologic cross section in Al Dhaid area, showing the main hydrogeologic units and vertical faults affecting the lower aquifer (modified from JICA 1996). The trace of the cross-section A-A’ is illustrated on Fig. 23.1.............................. 674 Showing contour maps showing lines of equal electrical conductivity (EC in μS/com) (a), total hardness (TH in mg/L) (b) and sodium adsorption ratio (SAR) in the study area, eastern UAE. (After Rizk and Alsharhan 2003a).............................................. 676 Showing soil classification map (a), groundwater suitability for irrigation map (b) and shallow groundwater resources map (c) in the Eastern Region of Sharjah Emirate in January 2000. (After Rizk and Alsharhan 2003a, b).......................................... 677 Map showing areas suitable for agriculture (dotted areas on Figure a) and areas of high groundwater potentialities (dotted areas on Figure b) in eastern UAE. (After Rizk and Alsharhan 2003a).............................................. 679 Sketch diagram showing the evolution of hydrogen (2H‰) and oxygen (18O‰) stable isotopes in surface water and groundwater during various processes. (After Yurtsever 1992)................................................................. 686 Concentration of hydrogen (2H‰) and oxygen (18O‰) stable isotopes in rainwater falling on the UAE. (After Rizk and Alsharhan 1999; Alsharhan et al. 2001)............ 687 Showing stable isotopes of hydrogen (2H‰) and oxygen (18O‰) in rain water falling on the UAE, Sultanate of Oman and Bahrain. (After Rizk and Alsharhan 1999; Alsharhan et al. 2001)............................... 688 Showing stable isotopes hydrogen (2H‰) and oxygen (18O‰) in rain water, aflaj water and different aquifer system in UAE. (After Rizk and Alsharhan 1999).................................. 689 Showing the oxygen stable isotopes (18O‰) versus TDS (mg/L) in groundwater of different aquifers and falajs water in the UAE. (After Rizk and Alsharhan 1999)................................................ 691 Showing concentration of stable isotopes of hydrogen (2H) and oxygen (18O) in groundwater of major aquifers in the UAE, Arabian Gulf countries and some Middle Eastern countries. (After Rizk and Alsharhan 1999)............................... 694

lx

Fig. 24.7 Fig. 24.8

Fig. 24.9

Fig. 24.10

Fig. 24.11

Fig. 24.12

Fig. 25.1 Fig. 25.2

Fig. 25.3

Fig. 25.4 Fig. 25.5

Fig. 25.6

List of Figures

Presentation of chloride ion concentration (Mmole) versus sulphate ion concentration (Mmole) in Wadi Al Bih limestone aquifer, northern UAE. (After Rizk et al. 2006)......... 695 Hydrogen (2H‰) and oxygen (18O‰) isotopes in the Liwa Quaternary sand aquifer in Liwa oasis and Bu Hasa oil-field brines, injected into the Miocene clastics aquifer in the Western Region of Abu Dhabi Emirate............................. 696 Plot of the nitrates isotopes in the Liwa Quaternary sand aquifer on a graph illustrating the δ15N and δ18O isotopic composition of nitrate sources. (Bleifuss et al. 2000)................................................................... 699 Showing correlation of nitrogen isotope ratio (δ15N) of nitrate (‰) with sodium ion concentration (mg/L) in groundwater samples collected from the Liwa Quaternary aquifer...................................................................... 700 Showing nitrogen isotope ratio (δ15N) values of nitrate in nitrogen sources and in groundwater samples collected from the Liwa Quaternary aquifer. Nitrification field is the field where nitrate is primarily derived from nitrification of ammonium in the soil................................. 701 Nitrogen (δ15N) and oxygen (δ18O) isotopic composition of the Liwa Quaternary aquifer, western UAE.................................................................. 702 The active and active cells data used for simulation and calibration of a numerical model. (From Al Wahedi 1997 and Alsharhan et al. 2001)........................................................... 713 Boundary conditions of the limestone aquifer and observation wells used for calibration of a numerical model for the aquifer. (From Al Wahedi 1997 and Alsharhan et al. 2001)..................... 713 Model-calculated groundwater levels, in meters, relative to mean sea level. Arrows illustrate groundwater-flow direction in the aquifer. (After Al Wahedi 1997 and Alsharhan et al. 2001)........................................................... 715 Predicted water-table elevations the aquifer during the period 1996–2005. (From Al Wahedi 1997 and Alsharhan et al. 2001)........................................................... 716 Contour map showing predicted groundwater levels in limestone aquifer of Wadi Al Bih basin for the period 1996–2005, assuming doubling of groundwater discharge of 1996. (Al Wahedi 1997; Alsharhan et al. 2001)...................... 717 Water balance in the Quaternary gravel aquifer, east Al Ain City under the predevelopment condition in the year 1995. (After Khalifa 1999; Alsharhan et al. 2001)................................................................. 719

List of Figures

lxi

Fig. 26.1

Water and electricity authorities in the UAE. (After Alghafli 2016)................................................................... 730

Fig. 27.1

Growth of population in the United Arab Emirates during the period 1975–2015, compiled from different sources................................................................. 759 Mean annual rainfall in the United Arab Emirates during the period 1934–2015, compiled from different sources................................................................. 759 Volumes of water accumulated behind dams in the UAE during the period from 1987 to 2013. (MOEW 2015)............................................................................ 762 Groundwater storage in Abu Dhabi Emirate in 2005, in Mm3. (After Ebraheem and Al Mulla 2009)............. 775 Groundwater storage in the rest of the emirates, in 2005, in Mm3. (Ebraheem and Al Mulla 2009)..................................... 776 Quantity of produced water by authority during the period 1990–2015 in the UAE, in million m3, in 2015. (FCSA 2017)................................................................. 779 Volumes of desalinated used by various sectors in UAE during 2008; (Left) percentage distribution, and (Right) distribution (in Mm3). (MOEW 2010)........................................ 779 Present and projected quantities of produced wastewater per emirate during the period 2007–2030, in Mm3. (FCSA 2017)............................................................................... 780 Water accumulated behind dams in the UAE during the period from 1987 to 2013. (MOEW 2015)................ 782 Distribution of water demand for agriculture, municipal and industrial and water per emirate in the UAE. (MOEW 2010)............................................................................ 783 Per capita water use (liter/day) in the UAE compared with per capita water share in several industrial, water-rich countries (Site of the MOCCAE, UAE).................... 784 The total annual water demand between the years 2000 and 2030, which is expected to increase from 4400 Mm3 in 2008 to 7100 Mm3 in 2030. (MOEW 2010)........................... 786

Fig. 27.2 Fig. 27.3 Fig. 27.4 Fig. 27.5 Fig. 27.6 Fig. 27.7 Fig. 27.8 Fig. 27.9 Fig. 27.10 Fig. 27.11 Fig. 27.12

List of Tables

Table 2.1 Table 2.2 Table 2.3 Table 2.4 Table 2.5 Table 2.6 Table 2.7 Table 2.8 Table 2.9 Table 2.10 Table 2.11 Table 2.12 Table 2.13 Table 2.14 Table 2.15 Table 2.16 Table 2.17 Table 2.18

Elements of natural hydrologic cycle and their approximate quantities................................................................ 19 Major hydrologic and morphometric characteristics of the world oceans..................................................................... 19 Total groundwater resources of the continents............................ 21 Major aquifer systems in the world............................................. 22 Global distribution of desalination capacities (in m3/day); the percentages are the contribution to the global desalination capacity.............................................. 23 World desalination capacities (in Mm3)...................................... 23 Application of treated wastewater for irrigation in 30 countries............................................................................. 27 Water resources of the continents............................................... 28 Total water withdrawal per sector and per capita on various continents in 2006..................................................... 28 Annual per capita water share in m3/year for different continents: Trends and projections.............................................. 28 The actual world population in 2015 in various continents and the predicted populations until 2030................... 29 Water available or used by source in MENA region................... 33 Invested water resources in different water sectors in the Arab World in 2000........................................................... 41 River basins, basin size (km2), river length (km) and average discharge (m3/year) of main river basins in Arab countries.............................................................. 43 Major aquifer systems in the Arab countries.............................. 43 Desalinization capacities in some Arab countries (in 1000 m3/day).......................................................................... 45 Total treated-wastewater production in some Arab countries..... 47 Total rainfall and percentage utilization through water harvesting in various Arab countries................................. 48 lxiii

lxiv

Table 2.19 Table 2.20 Table 2.21 Table 2.22 Table 2.23 Table 2.24 Table 4.1a

Table 4.1b

Table 4.2 Table 4.3a Table 4.3b Table 4.4a Table 4.4b Table 4.5a Table 4.5b Table 4.6

List of Tables

Water demand in the Arab countries by sector in 2011 as percentage of freshwater withdrawals....................... 48 Water losses from water distribution networks in various Arab countries............................................................ 49 Annual water resources in the GCC countries in Mm3............... 53 Per capita water share and water consumption in the GCC countries in Mm3/year.............................................. 53 Most important aquifers in the GCC countries........................... 55 Water consumption by sector in the GCC countries (in Mm3) in 2010......................................................................... 57 Summary of average minima, maxima and mean annual air temperature (°C), relative humidity (%), rainfall (mm), wind speed (km/hr) and evaporation (mm/d) in some meteorological stations in the UAE for the period 1976–2003............................................................ 117 Summary of average minima, maxima and mean annual air temperature (°C), relative humidity (%), rainfall (mm), wind speed (km/h) and evaporation (mm/day) in major meteorological stations in the UAE for the period 2003–2015............................................................ 119 Mean minimum, mean and mean maximum annual solar radiation (kWh/m2) for the period 2003–2015................... 122 Mean maxima and mean minima of air temperatures (°C) at various meteorological stations in the UAE for the period 1976–2003............................................................ 125 Mean maxima and mean minima of air temperatures (°C) at various meteorological stations in the UAE for the period 2003–2015................................................................................... 126 Average percentage of maxima and minima relative humidity (%) at some meteorological stations in the UAE for the period 1976–2003......................................... 130 Average percentage of maxima and minima relative humidity (%) at major meteorological stations in the UAE for the period 2003–2015............................................................ 131 Average minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 1976–2003............................................. 135 Average minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 2003–2015............................................................ 136 Calculation of monthly and annual potential evapotranspiration (in mm), at eight major meteorological stations in the UAE in 1988 (data collected by Garamoon 1996).................................................................... 141

List of Tables

Table 4.7 Table 4.8 Table 4.9a Table 4.9b Table 4.10 Table 4.11

lxv

Locations of major meteorological stations used for investigation of climate conditions in the United Arab Emirates during the period 2003–2015.............................. 142 Monthly rainfall records (in mm) from 34 metrological stations during the period 2003–2014. These data have been presented in Fig. 4.9................................................... 144 Maximum, mean, minimum average annual rainfall (mm) at major meteorological stations in the UAE for the period 1976–2004......................................... 146 Average monthly rainfall (mm) at 30 major meteorological stations in the United Arab Emirates for the period 2003–2015............................................................ 149 Temperature increase in the UAE airports during the period 1975–2013 (data obtained from the National Center of Meteorology and Seismology).................................... 161 Total annual reduction in emission of greenhouse gases in the UAE during the period 1994–2005................................... 162

Table 5.1

Uniformity coefficient (Cu), hydraulic conductivity (K) and infiltration capacity (Ic) of sand dunes and interdune areas in the Al Ain Region of the Abu Dhabi Emirate........................................................... 188

Table 6.1

Maximum water storage in dam reservoirs in Wadi Al Bih, Wadi Tawiyean and Wadi Ham in northeastern UAE........................................................................ 196 Morphometric parameters of major drainage basins in northern and eastern parts of the United Arab Emirates, based on data obtained from the Ministry of Climate Change and Environment.......................................... 204 Calculated runoff volume (in Mm3) runoff depth (in mm) and percentage of rainfall as runoff (%), for Wadi Sfini in the eastern mountain ranges of the United Arab Emirates (Area = 216 km2)......................................................................... 206 Calculated runoff volume (Mm3), runoff depth and percentage of rainfall as runoff for Wadi Sheikh in the eastern mountain ranges of the United Arab Emirates (Area = 32.8 km2)........................................................ 211 Calculated runoff volume (Mm3), runoff depth (mm) and percentage of rainfall as runoff in some drainage basins in the eastern mountain ranges of the United Arab Emirates for the period (1982–1990)................................. 212 Calculated runoff volume (Mm3), runoff depth (mm) and percentage of rainfall as runoff in selected drainage basins of Jabal Hafit, south of the Al Ain area............................ 213

Table 6.2

Table 6.3

Table 6.4

Table 6.5

Table 6.6

lxvi

Table 6.7 Table 6.8

Table 6.9

Table 6.10 Table 6.11 Table 6.12

Table 7.1

Table 7.2 Table 7.3 Table 7.4 Table 7.5 Table 7.6 Table 7.7

Table 8.1

List of Tables

Calculated coefficient of runoff for Wadi Al Bih, Wadi Tawiyean and Wadi Ham basins, from the fitted model.............. 217 Predicted average runoff volume (Mm3), overland flow velocity and ranking, according to overland-flow velocity and flood hazard of some drainage basins in northeastern UAE.................................................................... 218 Average runoff volume (Mm3), overland flow velocity and ranking, according to overland- flow velocity and flood hazard of selected drainage basins in Jabal Hafit area in the United Arab Emirates................................................ 222 Volume of surface water (Mm3), retained behind groundwater recharge dams in northeastern UAE during the period 1992–2005...................................................... 224 Fluctuation of groundwater levels (m), in observation wells at locations of groundwater-recharge dams in northeastern UAE during the period 1992–2005.................... 224 Flood volumes of the main wadis in the northern and eastern parts of the United Arab Emirates, in Mm3 during the period 2001–2005......................................... 225 1984–2004 records of the average annual rainfall (mm) at Khatt, Fujairah, Maddab and Bu Sukhanah meteorological stations (data obtained from the Ministry of Climate Change and Environment)........................................................... 237 Meinzer’s (1923) classification of springs according to discharge................................................................................. 237 1984–1991 records of the annual discharge (Mm3) of the UAE permanent springs.................................................... 238 Classification of the UAE permanent springs, according their discharge and Minzer’s (1923) ordering............................. 239 Results of chemical analysis of water samples from UAE permanent springs and surrounding shallow water wells..................................................................... 245 Salinity and electrical conductivity of UAE springs, during 1968–1994....................................................................... 246 Calculated values of Sodium Adsorption Ratio (SAR) and Electrical Conductivity (EC) of springs and shallow groundwater at Khatt, Maddab and the Al-Ain areas.................. 254 Type, length (m), mean velocity (m/s), discharge in liters per second (L/s), electrical conductivity microsiemens per cm (EC = μS/cm), total hardness (TH = mg/L) and sodium adsorption ratio (SAR) of active aflaj in the UAE, illustrated on Fig. 8.3, based on data from the Ministry of Environment and Water (MEW), UAE................................... 267

List of Tables

Table 9.1

Table 9.2

Table 9.3 Table 9.4

Table 9.5 Table 9.6

Table 9.7 Table 9.8 Table 9.9

Table 9.10 Table 9.11

Table 10.1 Table 10.2 Table 10.3

lxvii

Groundwater production from the FEWA well fields in the Wadi Al Bih basin during the periods 1991–1995 and 2010–2014, based on data from the Ministry of Environment and Water........................................................... 283 Results of chemical analysis of groundwater samples collected during April 1996 from the Ministry of Electricity and Water (MOEW) well field discharging the Wadi Al Bih limestone aquifer.............................................. 287 Chemical analysis of groundwater samples collected during September 1996 from the water well field discharging Wadi Al Bih limestone aquifer.................................................... 289 Comparison between Al Bih and Burayrat groundwater chemistry in 1996 and 2014 with the World Health Organization (WHO 1984) and Gulf Cooperation Council countries (GSO 2008) standards for drinking water........................................................................ 292 Classification of groundwater in Wadi Al Bih limestone aquifer, according to its suitability for irrigation........ 296 Trace elements measured in water well fields in the Wadi Al Bih Basin versus the international (WHO 1984) and regional (GSO 2008) drinkingwater standards............................................................................ 297 The use of hydrochemical parameters for identification of the processes affecting water quality in Wadi Al Bih limestone aquifer.................................................................. 298 Major (A), minor and trace (B), chemical constituents (mg/L) in groundwater of Mubazzarah water field, Jabal Hafit, in the Al Ain area, the eastern UAE................ 302 Concentration of radioactive elements and stable isotopes of oxygen (18O) and hydrogen (2H) in groundwater of the Mubazzarah water field in Jabal Hafit of the Al Ain Region of the Abu Dhabi Emirate........................................................... 304 Main aquifers and uses of their water in the Bu Hasa oil field in the western UAE (compiled from NDC-USGS 1996)...................................................................... 305 Porosity, permeability, transmissivity and storage coefficient of limestone aquifers in the western UAE. (After Hassan and Al Aidarous 1985)......................................... 306 Number of stream channels in each stream order in the five sub-basins constituting the Al Dhaid Super Basin............................................................ 317 Drainage lines analysis of the Al Dhaid Super Basin, using topographic maps, scales 1:50,000 and 1:100,000............ 321 Morphometric parameters of the Al Dhaid Super Basin, based on linear analysis of natural drainage lines....................... 321

lxviii

Table 10.4 Table 10.5 Table 10.6 Table 11.1 Table 11.2 Table 11.3 Table 11.4 Table 11.5

Table 11.6 Table 12.1 Table 12.2 Table 12.3 Table 12.4 Table 12.5 Table 12.6

List of Tables

Age, thickness and distribution of lithologic and hydrogeologic units in the Al Dhaid Super Basin, compiled various sources (after JICA 1996; Al Mulla 2001)..... 326 Geophysical properties and hydraulic parameters of the main water-bearing units in the Al Dhaid super basin, compiled from JICA (1996) and Al Mulla (2001)...................... 326 Hydraulic heads in the Al Dhaid area during the period 1985–1998.................................................................. 330 Summary of hydraulic properties of the eastern gravel aquifer in various shallow wells in the Fujairah Emirate, Eastern Region of the UAE.................. 341 Water-well fields discharging the western gravel aquifer around Al Ain city and the aquifer’s hydrogeologic and hydrochemical properties............................. 366 Rates of groundwater pumping for agriculture (Mm3), forestry and landscaping in 1985, from the western gravel aquifer in the Al Ain area (Hyde 1992)............................ 370 Water consumption in Al Ain between 1990 and 2000, compared to consumption rates in 2010..................................... 370 Storativity (S) and transmissivity (T) of the western gravel aquifer in the Al Ain area, and their comparison with the Quaternary sand aquifer and the limestone aquifer, derived from different methods................................................... 372 Hydrochemical and natural isotopic properties of groundwater flow systems in the UAE........................................ 375 Hydraulic conductivity (K) and uniformity coefficient (Cu) and of sand samples from the Liwa aquifer in Liwa Oasis, in the western Region of the UAE...................... 401 The EC (μS/cm), pH, TDS (mg/L) and concentrations of major ions (mg/L) in groundwater samples from the Liwa aquifer at Liwa oasis, western UAE.................... 404 The pH, TDS (mg/L) and concentration of major ions (mg/L) in groundwater samples from the Liwa aquifer in the Liwa area, western UAE................................................... 405 Contour maps showing the saturated thickness (m) and hydraulic heads (m amsl) in the Liwa aquifer, western UAE............................................................................... 414 Concentration of F− and trace metals in the Liwa aquifer at the Liwa oasis and Bu Hasa oil field, western UAE in 1999.................................................................. 416 Water quality of the Liwa aquifer in the Liwa and Bu Hasa areas, versus regional (GCC) and international (WHO 1984) the) drinking water standards............................................................. 420

List of Tables

lxix

Table 12.7

Sensitivity of irrigation water for various crops, based boron concentration (mg/L), in the water......................... 421 The NO3−, TH (mg/L) and SAR in the Liwa aquifer in the Liwa and Bu Hasa areas.................................................... 421 The 2H and 18O isotopes (‰) in the Liwa aquifer at the Liwa oasis and Bu Hasa oil field, western UAE............... 424

Table 12.8 Table 12.9 Table 14.1 Table 14.2 Table 14.3 Table 14.4 Table 14.5

Estimated and predicted water resources and water demand in the UAE for the period 2015–2025 in MCM............ 457 Desalination technologies existing in the UAE........................... 458 Production of existing desalination plants in the UAE in 2008...................................................................... 459 The pre-treatment chemicals used in desalination plants............ 461 Chemical composition of raw water, feed water, produced water and brines of some desalination plants in the UAE in 2008. The EC is measured in in microsiemens per centimeters (μS/cm). The TH and concentrations of ions and SiO2 are expressed in milligrams per liter (mg/L)................ 464

Table 15.1

Treated and reused wastewater in the United Arab Emirates (in Mm3/year), in 2009 (MOEW 2010; AMPD 2007)................ 474 Table 15.2 Numbers of wastewater treatment plants and their produced desalinated water during the period 2011–2015 in Mm3............ 474 Table 15.3 The quantities of wastewater production in various emirate in million m3 per year during the period 2007–2030  (Statistics Center of Dubai 2007, 2015)...................................... 475 Table 15.4 The physical and chemical parameters of raw wastewater in the United Arab Emirates........................................................ 478 Table 15.5 Physical and chemical parameters of effluent from major wastewater treatment plants in the United Arab Emirates.......... 479 Table 15.6 Accepted limits for reuse of treated wastewater in restricted and unrestricted irrigation Concentrations are given in milligrams per liter.................................................................. 485 Table 15.7 Dubai Municipality accepted limits of sludge used in agriculture. Concentrations (in μg/L)...................................... 486 Table 15.8 Comparison of the properties of treated wastewater in the UAE, with the WHO (1989) standards for wastewater used for irrigation............................................... 488 Table 15.9 Treated wastewater production in the eastern and western region of Abu Dhabi Emirate.................................. 491 Table 15.10 Volume of water produced by wastewatertreatment plants in the Emirate of Ras Al Khaimah.................... 495 Table 16.1

Sodium adsorption ratio (SAR) ranges and its possible effect on plant and soil in the study area (Hem 1985)................ 503

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Table 16.2

Table 16.3 Table 16.4 Table 16.5

Table 17.1

Table 17.2

Table 17.3 Table 17.4 Table 17.5 Table 17.6 Table 17.7 Table 18.1 Table 18.2

List of Tables

Comparison of the average individual’s water share, per meter per year, in the Gulf Cooperation Council (GCC) countries between 1970 and 2000, in m3 per capita per year.............................................................. 505 Average per-capita consumption of fresh water in some countries, and evolution of per-capita freshwater use in the UAE during the period 1997–2000............................. 505 Number of farms, and their areas in Dunam, that have productive or non-productive water wells and their total numbers, in the UAE in 2005...................................................... 507 Groundwater salinity, in milligrams per liter, obtained from observation wells in northern and eastern UAE during the period 1981–2005...................................................... 510 Results of chemical analyses of bottled water sold for drinking in various emirates of the United Arab Emirates. The electrical conductivity (EC) is in microsiemens per centimeter (μS/cm), concentrations are expressed in milligrams per liter (mg/L); and the heavy metals Zn, Ni, Ba, Pb and Se were not detected (ND) in all samples............................................................................... 534 Chemical analyses of desalinated water used for drinking and other domestic purposes in the Emirate of Umm Al Quwain, the UAE. The electrical conductivity (EC) is in microsiemens per centimeter (μS/cm) and concentrations are in milligrams per liter (mg/L). The fluoride ion (F−) was below detection limit in all tested desalinated water samples........................................ 535 Results of chemical analyses of groundwater from Al Ain, Ajman, Sharjah, Ras Al Khaimah and Fujairah in the United Arab Emirates................................... 536 Inorganic chemicals in water used for domestic purposes in the United Arab Emirates........................................................ 539 Standard deviations of pH, TDS, cations, anions and trace metals........................................................................... 540 Detection limits (μg/L) and wavelengths (mn) of inorganic chemicals in water samples..................................... 543 Inorganic chemicals in different water types in UAE against different standards............................................. 544 The numbers of groundwater samples collected for chemical analysis from Wadi Al Bih limestone aquifer in November 2014 and June 2015............................................... 551 Simulated volumes of various water types under different scenarios compared with the predevelopment figures............................................................... 557

List of Tables

lxxi

Table 19.1

Increase in domestic water consumption during the period 2004–2008 in the United Arab Emirates.................... 600 Annual water consumption in the United Arab Emirates, based on data from the Ministry of Energy................ 604 Average daily water consumption per capita in the UAE in liters per day, based on data from the Ministry of Energy....................................................... 605

Table 19.2 Table 19.3

Table 20.1

Data of groundwater recharge dams in the UAE, obtained from the Ministry of Climate Change and Environment......................................................................... 624

Cultivated area (in hectare = 10,000 m2) per emirate in 2003 in the UAE (based on data from FAO 2008).................. 633 Table 21.2 Distribution of land use (area in Donum = 1000 m2) by emirate in the UAE in 2015 (after National Bureau of Statistics 2015)........................................................................ 633 Table 21.3 Distribution of farm land use (area in Donum = 1000 m2) in the East Coast area of the UAE (after Al Qaydi 2014)........... 634 Table 21.4 Estimated distribution of farms and water wells in the Eastern Region of the UAE in 2012 (After Al Qaydi 2014)................................................................. 634 Table 21.5 Mainland area (in hectare = 10,000 m2) and number of farms per emirate in 2003 in the UAE................ 635 Table 21.6 Numbers of farms and their total areas in the emirates in 2005................................................................ 635 Table 21.7 Areas suitable for crop production in the UAE (Hectare = 10,000 m2), based on data from the Ministry of Environment and Water (after the World Bank 2005)........................................................ 640 Table 21.8 Quantities and areas of farms irrigated by modern irrigation techniques versus the quantities and areas of farms irrigated by traditional methods in 2005 (after the World Bank 2005).......................................... 641 Table 21.9 The areas and quantities of farms applying localized and sprinkler irrigation in the UAE in 2003 (after FAO 2008)......................................................................... 641 Table 21.10 Numbers and areas (Dunam = 1000 m2) of greenhouses used in protected agriculture in the United Arab Emirates in 2005........................................... 646 Table 21.1

Table 22.1

Calculation of dune-covered areas and interdune areas around Al Ain city, based on field survey and satellite images.................................. 666

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List of Tables

Table 22.2

Calculation of evaporation rate (m3/year) from dune and interdune areas C1 and C2, west of Al Ain Region of Abu Dhabi Emirate, based on supervised classification............................................... 666

Table 23.1

Hydrogeologic units identified with the use of the transient domain electromagnetic (TDEM) survey of hydrogeologic units in Al Dhaid area, Sharjah Emirate (after JICA 1996)........................................................................ 672 Describing summary of hydrogeologic and geoelectric properties of aquifer systems in the study area, eastern UAE (after JICA 1996)................................................... 674 Input data of the analytical GIS model for Al Dhaid area, eastern Sharjah Emirate, and their applications................. 678 Sample of a GIS model outputs for Al Dhaid area, eastern Sharjah Emirate and their spatial distribution................. 679

Table 23.2 Table 23.3 Table 23.4 Table 24.1 Table 24.2 Table 24.3 Table 24.4

Table 26.1 Table 26.2 Table 26.3 Table 26.4 Table 26.5 Table 26.6 Table 26.7

Isotopes of hydrogen, oxygen and carbon used in water resources studies............................................................ 684 Listing minimum, average and maximum values for stable isotopes of hydrogen (2H‰) and oxygen (18O‰) in rainwater of Bahrain, Oman and the UAE................. 688 Describing chemical and isotopic characters of groundwater flow systems in the UAE................................... 689 Listing minimum, average and maximum values for stable isotopes of hydrogen and oxygen in groundwater of the UAE......................................................... 690 Environment and water institutions and agencies in charge of water affairs in the UAE during the period 1975–2016.................................................................. 731 A few federal, regional and international agreements and laws affecting the environment and water resources in the UAE (MOEW 2010)......................................................... 739 Competent authorities responsible for management of natural water resources in different emirates.......................... 740 Laws and decrees issued by various emirates for protection of groundwater resources in the UAE (Rizk 2014).............................................................. 742 Authorities in charge of regulation and use of desalted water in the UAE...................................................... 745 Agencies responsible for collection, treatment and control of wastewater in the UAE........................................ 746 Standards for reclaimed water use.............................................. 747

List of Tables

lxxiii

Table 26.8

Standards for industrial wastewater discharges into public sewage network. Concentrations are in mg/L and EC is in μS/cm.................................................. 748 Table 26.9 Showing specification of Sharjah Municipality for effluent water reuse for land irrigation purposes................... 749 Table 26.10 Showing standards of Dubai Municipality for effluent reuse and discharge.................................................. 751 Table 27.1 Table 27.2

Table 27.3 Table 27.4a Table 27.4b Table 27.5 Table 27.6 Table 27.7 Table 27.8 Table 27.9 Table 27.10 Table 27.11

Water sources in the United Arab Emirates................................ 758 Population growth in each emirate of the UAE during the period 2012–2016 (million), and their areas (km2)................................................................... 758 Approximate figures of nonconventional and conventional water resources............................................................................ 760 Summary of hydrogeology and hydrogeochemistry of major aquifers in the UAE...................................................... 768 Summary of lithologies, hydraulic properties and water quality of major aquifer systems in the United Arab Emirates............................................................................. 769 Groundwater reserves of different emirates per groundwater quality in 2005................................................. 775 The number of major desalinated plants, by type and authority, in the UAE, in 2015.............................................. 777 Quantity of produced water by authority during the period 1990–2015 in the UAE, in Mm3, in 2015.................. 778 Present and projected water sources and demands (Mm3), for the period 2002 and 2025, in the UAE.................................................................. 781 Individual’s water consumption during the period 1997–2002.................................................................. 783 Per capita water use in liter/day (Site of Ministry of Climate Change and Environment, based on data from the Eurostat and USGS)......................................... 783 Integrated water resources management strategies..................... 787

List of Photographs

Photo 3.1

Photo 3.2

Photo 3.3

Photo 3.4 Photo 3.5

Photo 3.6 Photo 3.7

Outcrops of limestone rocks belong to the Ru’us Al Jibal massive and represent the northern wall of Wadi Al Tawiyean. The body of the Wadi Al Tawiyean dam is in the lower right section of the photograph............................................................ 68 Ophiolite rocks represent a part of the northern Oman Mountains. These rocks are in the entrance of Wadi Shi, Fujairah Emirate, which has palm trees in the middle and runs along the unpaved track on the right of the photo.............................................................. 69 Ophiolites are part of northern Oman Mountains. These rocks are in the entrance of Wadi Shi, Fujairah Emirate, which has palm trees in the middle and runs along the unpaved track on the left of the photo......................... 69 Joint sets in the upper photograph and bedding plans in the lower one affect the ophiolitic rocks forming the right wall of Wadi Shi, Fujairah Emirate............................... 70 Ophiolite rocks represent a part of the northern Oman Mountains in the United Arab Emirates. It forms the ophiolite aquifer in the Eastern Region. Joint sets and other structural elements increase the porosity and specific capacity of the aquifer............................................. 70 Ophiolite rocks forming the right wall of Wadi Shawkah. Joint sets and other structural elements increase the porosity and specific capacity of the ophiolite aquifer.............................. 71 Clayey deposits resulting from weathering of ophiolite rocks, fill the opening caused by geologic structures and reduce the aquifer’s hydraulic conductivity................................................................. 71

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lxxvi

Photo 3.8

Photo 3.9

Photo 3.10

Photo 3.11 Photo 3.12 Photo 3.13

Photo 3.14

Photo 3.15 Photo 3.16

Photo 3.17

Photo 3.18 Photo 3.19

List of Photographs

The white magnesite veins form as a result of weathering of ophiolites. The magnesite fill the openings caused by geologic structures and reduce the aquifer’s hydraulic conductivity................................................................. 72 Ophiolite rocks represent a part of northern Oman Mountains. The rocks are overlooking Ain Al Ghomour, Fujairah Emirate, which is surrounded by palm trees on the lower left of the photograph............................................. 72 Ophiolite rocks represent a part of the eastern mountain ranges in the UAE. The rocks make up the right wall of Wadi Shawkah, which runs along the asphaltic road on the lower right of the photograph........................................... 73 Rock outcrops in Jabal Hafit, as it seems from the Wagan–Al Ain road on the lower left of the photograph........................................................................ 74 Rock outcrops in Jabal Hafit in Al Ain, as can be seen on the right side of the wadi, which runs across the middle of the photograph............................................................ 74 Rock outcrops in Jabal Hafit at the entrance of Mubazzarah area, north of Jabal Hafit. The green color is spreading as can be seen on the lower left of the photograph............................................. 75 Limestone rock outcrops near the top of Jabal Hafit. The photo shows karst features resulting from chemical weathering of the mountain. This phenomenon increases secondary porosity and the aquifer’s storage.............................. 75 Outcrops of limestone rocks, east of Al Ain city near Al Buraimi. The sand dunes around these mountains receive recharge from rains falling on these mountains.............. 76 The UAE’s eastern coastal plain. It extends between the eastern mountain ranges, in background of the photograph, and the Gulf of Oman. Notice the concentration of farms, which appear as a green line, at the outlets of main wadis......................................................... 77 The eastern coastal plain extends between the eastern mountain ranges and the Gulf of Oman. Its width varies between 4 and 8 km. Notice the concentration of farms at the outlets of main wadis, which appear as green line in the middle of the photograph...... 77 Sediments of the eastern coastal plain range from large rock masses close to the mountains, and sand, silt and clay near the Gulf of Oman in UAE............................... 78 Outlet on an active drainage basin, in the northern Oman Mountains in the UAE, entering the eastern coastal plain................................................................................. 78

List of Photographs

Photo 3.20

Photo 3.21 Photo 3.22

Photo 3.23 Photo 3.24

Photo 3.25 Photo 3.26

Photo 3.27

Photo 3.28

Photo 3.29

Photo 3.30 Photo 3.31

lxxvii

The western gravel aquifer, near the Al Fayah Mountains in Al Ain Region, between the mountains in the east and sand dunes, in the lower half of the photograph, in the west................................................................................... 79 Active, linear sand dunes on the right side of the Al Ain–Al Wagan road..................................................................... 79 Active, linear sand dunes on the right side of the Al Ain–Al Wagan road. Notice the alternation of dune lines and flat, interdune areas, which are usually covered by farm vegetation......................................................... 81 Active, star sand dunes on the right side of the Al Ain–Al Wagan road..................................................................... 81 Sand dunes on the right side of the Sharjah–Al Dhaid road, indicate a shallow aquifer, where the roots of palm trees possibly reach the groundwater table.................................................................. 82 Coastal sand dunes on the right side of the Ras Al Khaimah–Sharjah road. Sabkha deposits separate the coastal dunes and internal sand dunes................................... 83 One of the active barchan dunes on the right side of the Al Dhaid–Sharjah road. Ripple marks on the dune surface help to determine the prevailing wind direction....................................................... 84 Ripple marks in this photograph show that the prevailing wind direction is from left to right. Sands of these dunes are well-sorted and rounded, facilitating large infiltration rates of rains falling on these dues towards groundwater............................................ 84 Old, fixed sand dunes as a result of growing vegetation on their surface, which limits sand movement to a great extent. These dunes are on the right side of the coastal road between Umm Al Quwain and Sharjah........ 85 Contact line between old sand dunes, covered by natural vegetation in the upper part of the photograph, and coastal sabkhas along Arabian Gulf coast between Ras Al Khaimah and the Umm Al Quwain road......................... 85 Coastal sabkhas occupy low areas between coastal sand hills. The photograph also shows the white coastal sand dunes in the upper part of the photograph.............. 86 The clayey, highly saline sabkha deposits are rich in coastal life forms. This sabkha lies along the Arabian Gulf coast between the cities of Umm Al Quwain and Ajman.................................................. 87

lxxviii

Photo 3.32

Photo 3.33 Photo 3.34 Photo 3.35

Photo 3.36

Photo 3.37

Photo 3.38

Photo 3.39

Photo 3.40

Photo 6.1 Photo 6.2 Photo 6.3 Photo 6.4

List of Photographs

Saline deposits, a part of coastal sabkhas, on the right side of the coastal road between Ras Al Khaimah and Umm Al Quwain. The trees in the photograph are salt-tolerant mangrove trees, growing in coastal areas in the United Arab Emirates........................................................ 87 Example of inland sabkha in Al Jurf area, Ajman Emirate. The water table is very close to the land surface, causing evaporation directly from the groundwater.................... 88 Wadi terraces are alluvial deposits with good soil and high groundwater potential. Wadi Ham terraces are intensively cultivated as shown in this photograph............... 88 Drainage basins in eastern UAE are dry most of the year. However, they must be kept clean because it becomes active in the rainy season and carries flood water, which recharges groundwater.................................. 91 Wadi Shawhak dam in Ras Al Khaimah Emirate is one of the most successful recharge dams in the UAE and its reservoir is usually filled with flood water one than once a year......................................... 91 Alluvial deposits in Wadi Ham indicate a good aquifer, which is recharged from the rains falling on the mountains surrounding the wadi floor............................................................................... 92 Earth breaker in Wadi Safad of Fujairah Emirate. Notice the accumulation of dry clays with mud cracks retained behind the breaker after flood water infiltrated or evaporated.............................................................. 92 Wadi Tawiyean, as seen from the dam site. The limestone outcrops of the wadi witness the extensive crushing activities needed for cement factories..................................................................... 93 Wadi Al Mawrid showing the baseflow water in the wadi floor constituting a continuous water supply feeding Falaj Al Mawrid........................................ 93 V-notch weir used for measuring volumes of surface runoff in small streams, fixed in Wadi Siji, Fujairah Emirate..................................................... 197 Flood-recording device fixed in Wadi Siji, Fujairah Emirate.......................................................................... 197 Flood-recording device fixed in Wadi Al Bih, Ras Al Khaimah Emirate............................................................. 198 Reservoir of Wadi Shawkah Dam, Ras Al Khaimah Emirate. The reservoir is almost full throughout the year because it receives flood waves more than once a year during

List of Photographs

Photo 6.5

Photo 7.1 Photo 7.2 Photo 7.3 Photo 7.4 Photo 8.1

Photos 8.2

Photo 8.3

Photo 8.4 Photo 8.5

lxxix

winter and summer. This image shows the reservoir after a flood in November 2004.................................................. 199 Reservoir of Wadi Ham Dam, Fujairah Emirate. The reservoir catches runoff water during rainy years, remaining dry in years with low mean annual rainfall....................................... 199 Khatt spring in the Ras Al Khaimah Emirate, discharging karstic limestone of the Ru’us Al Jibal Mountains, the northern UAE..................................................... 234 Al Ghomour spring in the Kalba area of the Sharjah Emirate, south Eastern Coastal area of the UAE........................ 235 Maddab spring in the Fujairah Emirate, Eastern Coastal area of the UAE.............................................................. 236 Bu Sukhanah spring in the Al Ain area of the Abu Dhabi Emirate..................................................................... 236 Depicts the Shari’a of Falaj Al Mualla, Emirate of Umm Al Quwain: (a) women’s Shari’a and (b) men’s Shari’a. Both Sari’as are now dry because of groundwater over-pumping in the Falaj recharge area. (Photo taken by Humaid 2012)........................................... 263 Shows that the discharge of Aflaj Al Gheli depends on rainfall; Falaj Al Mawrid has high discharge and can overflow, in winter (left). The same falaj has low discharge, or dries up, during summer (right)............... 264 Depicts one of Aflaj Al Daudi, Falaj Al Raheeb, one of the three mother wells at the foothills of high mountains (a), closer look at mother well (b), a covered surface channel to minimize evaporation (c) and dense palm garden fed by Falaj water (d)............................ 269 Flowing Falaj Khatt in the Emirate of Ras Al Khaimah in northern UAE (left), a Hadouri of Aini Falaj, ceased after diversion of the spring water feeding the Falaj (right)............... 270 Measurement of active area and flow velocity of Falaj Sakamkam Al Daudi in the Fujairah Emirate to calculate the discharge............................................................ 271

Photo 9.1

Water wells of the Mubazzarah well field, discharging warm, saline groundwater from the Al Dammam aquifer in northern Jabal Hafit, south of the Al Ain Region of the Abu Dhabi Emirate  (Rizk and Alsharhan 2008)......................................................... 309

Photo 10.1

Ophiolite rocks near Wadi Shawkah. Notice the density of fractures and faults, which makes the rocks a good aquifer, providing the Wadi Shawkah Dam reservoir with water all year............................................... 323

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List of Photographs

Photo 10.2

Fractures, faults and joint systems affecting the ophiolite aquifer, increase its secondary porosity and hydraulic conductivity in the eastern and northeastern regions of the UAE...................................................................... 323

Photo 11.1

Thick alluvial sediments on the right side of Al DhaidFujairah road indicates a part of the gravel aquifers in the eastern UAE...................................................................... 337 Thick alluvial sediments on the right side of Al DhaidFujairah road indicates a part of the gravel aquifers in eastern UAE............................................................................ 337

Photo 11.2

Photo 14.1

One of the desalination plants in the UAE.  Desalinated water meets more than 90% of domestic water demand in the country................................... 459

Photo 15.1

Wastewater-treatment plant, the Ras Al Khaimah Emirate, United Arab Emirates. (Photo from Namdar 2016)......................................................... 593

Photo 16.1

Disposal site of RO desalination brines in unlined open bits in southeastern UAE. (From Mohemed et al. 2005)...................................................... 521 Red-tide blooms along the coasts of Dubai Emirate (a) and Ras Al Khaimah Emirate (b).......................................... 524

Photo 16.2 Photo 18.1

Photo 18.2

Photo 18.3

Photo 18.4

Locations of water wells with a presence (red) and absence (black) of coliform when tapping the limestone aquifer in the Al Burayrat area (open circles) and Wadi Al Bih basin (closed circles) in November 2014........ 553 Locations of the presence (red) and absence (black) of T. coliform in water-well tapping of the Wadi Al Bih limestone aquifer in Al Burayrat area (open circles) and Wadi Al Bih basin (closed circles) in June 2015.................. 554 Al Burayrat desalination plant and surrounding human activities may represent potential sources of groundwater pollution in the study area. Percolation of surface water from the Al Burayrat dam reservoir can contribute to bacterial pollution of Wadi Al Bih limestone aquifer......................................................................... 554 The pollution source of wells WB-AT and WB-H2 is a result of urban development, while the bacterial contamination of WB-10 and WB-37 is related to agriculture activities on nearby farms..................................... 555

List of Photographs

Photo 20.1 Photo 20.2 Photo 20.3 Photo 20.4 Photo 20.5 Photo 20.6

Photo 20.7 Photo 20.8 Photo 20.9 Photo 20.10 Photo 20.11 Photo 20.12 Photo 20.13 Photo 20.14 Photo 21.1 Photo 21.2 Photo 21.3

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One of earthen barriers in Wadi Furfar, Northern Agricultural Area, Ras Al Khaimah Emirate.............................. 612 Impact of an earthen dam on agriculture in Wadi Furfar, Ras Al Khaimah Emirate............................................................. 612 Habisat Wadi Al Mawrid, Ras Al Khaimah Emirate................... 613 Small berka basin for harvesting of rainwater in Wadi Naqab, Ras Al Khaimah Emirate................................... 614 Falaj Al Mawrid Ras Al Khaimah belongs to aflaj Al Gheli. The falaj discharge increases during the rainy season and decreases, or may become nil, in the absence of rain........... 615 Falaj Al Qattara in the Al Ain area, belongs to aflaj Al Daudi. The falaj used to depend on shallow groundwater in the western gravel aquifer, but it is now dry because of excessive groundwater pumping............................................. 616 Reservoir of Wadi Ar Rafisah Dam, Wadi Shi, Fujairah Emirate, as of May 2006............................................... 619 Reservoir of Wadi Safad Dam, Fujairah Emirate, as of March 2006......................................................................... 619 Reservoir of Wadi Shawkah Dam, Ras Al Khaimah Emirate, November 2004............................................................ 620 Reservoir of Wadi Al Wurayah Dam, Fujairah Emirate, as of October 2004...................................................................... 620 Reservoir of Wadi Al Ruheib Dam, Fujairah Emirate, as of October 2004...................................................................... 621 Reservoir of Wadi Al Tawiyean Dam, Fujairah Emirate, as of October 2004...................................................................... 621 Reservoir of Wadi Al Bih Dam, Ras Al Khaimah Emirate, as of October 2004...................................................................... 622 Reservoir of Wadi Al Baseerah Dam, Fujairah Emirate, as of October 2004...................................................................... 622 Drip-irrigation technique in greenhouses of protected agriculture in the UAE saves water and increases productivity. (From Al Asam 1996)............................................ 643 Sprinkler-irrigation technique is used in dense field crops, fodder and green areas irrigated by low-salinity water................................................................... 644 Bubbles-irrigation technique is best for the irrigation of date palms, fruit and ornamental trees because it irrigates a large group of trees simultaneously and in a short period of time....................................................... 644

Part I

Introduction to Water Resources

This introductory part to water resources of the United Arab Emirates (UAE) summarizes the 28 chapters constituting this book. The introduction discusses the factors affecting water resources such as geomorphology and geology, climate and global warming and climate change. The introduction also provides an inventory of conventional and non-­conventional water resources in the UAE, highlights the challenges facing water resources and suggests water conservation strategies for water harvesting and management of agriculture water demand. The review of water resources includes global figures about traditional and alternative water resources, water challenges and demographic drives. Water resources in the Middle East and North Africa (MENA) region, Arab world and the Gulf Cooperation Council (GCC) countries were also reviewed with discussion on available water resources, water demands and water challenges, with particular emphasis on the demographic drive. The global conventional water resources include water in the oceans, continents, swamps, glaciers and ice sheets, lakes and reservoirs and rivers; while the non-­ conventional water resources are desalinated water and treated wastewater. In the present, the world consumes 8.4% of available water resources, and in 2025 the consumption is predicted to reach 12.2%. The annual renewable global water resources are 42,750 km3. The distribution of this water among continents varies in time and space. Asia and South America receive the largest share of earth’s water, while Europe and Australia receive the lowest share. The rapid increase in population lowered the per capita water share from 12,900 m3 in 1970 to 5926 m3 in 2014. The largest water shortage is in Africa, where the per capita water share dropped to one-third. During the same period, the per capita water share dropped to one-half in Asia and South America. The main global water challenges are the uneven distribution of water resources, water quality problems, escalating demands and climate change. The MENA region is mostly arid and dry, receiving less than 1% of the earth’s water. The number of countries suffering from water shortage is expected to reach 18 countries in 2025, mostly are Arab countries. The annual per capita water share

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in most of the MENA countries is less than 200 m3, while the United Nations water poverty line is 1000 m3/person/year. About 15% of the world population receives over 50% of their water resources from neighboring countries, and many areas started witnessing disagreements around water shares. The Arab countries are located in the heart of the MENA region, where rainfall is scarce, evaporation is very high and surface water resources are almost absent, except for a few rivers, originating in a more humid area outside the borders of Arab countries, and a limited number of low discharge springs. The per capita water share is steadily declining, and water challenges are over-exploitation of groundwater resources, lack of integrated water management, natural variability, absence of integrated management and development of shared water resources, water pollution and negative impacts of climate change on water resources. The share of the Gulf countries of the total water resources in the Arab region is less than 5%. The water demands always surpass available conventional resources, which puts these countries, particularly Saudi Arabia and UAE in the lead of water desalination in the world. Both countries produce 30% of the global production of desalinated water, and the Gulf region produces more than 50% of the world’s production. The main water challenges include reduction of non-revenue water, industrial water and wastewater management, water use and policy reform in the agricultural sector.

Chapter 1

Introduction to Water Resources of the United Arab Emirates

Abstract  This chapter summarizes the book ten parts. Part one provides an overview of global water resources. Part two discusses the impact geomorphology on surface water resources and influence of geology on groundwater. Part three describes the main features of the UAE climate and illustrates the impacts of global warming and climate change on water resources. Part four presents the results of investigating seasonal floods, springs, aflaj systems and groundwater resources. Part five discusses desalinated water and treated wastewater. Part six identifies the challenges facing water resources and investigates groundwater pollution. Part seven deals with water conservation, water harvesting techniques and the positive impacts of application of modern irrigation technologies on water resources conservation. Part eight describes the use of remote sensing, GIS, isotope hydrology and modeling techniques in water resources investigations. Part nine analyzes water governance and provides recommendations for improving integrated water resources management. Part ten summarizes water resources and water demands, and efforts of maximizing resources and managing demands. The volume ends by the conclusions, covering all the themes of this book. The scarcity of basic references on water resources in the Arab countries in general, and the Arabian Gulf region in particular, was the motivation to prepare this book. The United Arab Emirates (UAE) is no exception as a country about which there is no single reference book on water resources. In the meantime, there is an urgent need for a comprehensive text book that can provide an inventory of available water resources, diagnose the main challenges facing conventional and nonconventional water sources, and suggest viable methodologies and technologies for improvement of the current water-resources management in the UAE. The authors participated in writing the first book on the hydrogeology of the Arabian Gulf and adjoining areas, published by Elsevier in 2001. The authors

© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_1

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s­pecialize in geology and hydrogeology and have been teaching and conducting scientific research on water resources of the UAE for more than two decades. Therefore, it was important to compile the results of their research efforts, along with the results of other relevant studies published by researchers, released by relevant authorities in the UAE and included in publications of regional and international organizations, in one reference book. This book constitutes a main reference on water resources in the UAE for university students, researchers and the general public. The scientific research on which this book is founded was initially written in English and published in regional and international journals, which limits the access to information to the English-­ speaking community. In 2008, the authors wrote an Arabic version of a reference book on water resources in the UAE, to give the Arabic-speaking readers, researchers and students access to this vital information. However, the huge volume of information added since 2008 until now necessitated preparation of this book to serve as a basic, comprehensive reference on almost all aspects of water resources in the UAE. The natural water resources in the UAE, which have historically been limited, are facing serious challenges due to the ambient natural conditions represented by the scarcity of rain, high evaporation rates, rapid population growth, expansion of cultivated lands, exceptional urban development and increased industrial activities. These conditions require availability of information on conventional water resources such as flash floods, natural springs, aflaj systems and groundwater, and non-conventional water resources including desalinated water and treated wastewater, for government agencies, private sectors and foreign investors as well. To address the main issues regarding water resources in the UAE, the authors has sought to provide the reader of this book with comprehensive and clear answers for several basic questions about water resources in the UAE, their sources, the main challenges facing water resources and suggested solutions. This book contains 28 chapters and is divided into ten parts as follows: Part I (Chaps. 1 and 2) provides an introductory statement for each chapter and an overview on water resources ranging from global to local perspectives. Part II (Chap. 3) illustrates how geomorphology controls the volume and direction of seasonal floods, while geology determines the nature, setting and geologic structures of the aquifers and their influences on the presence, movement recharge and quality of groundwater. Part III (Chaps. 4 and 5) summarizes the main features of the UAE climate and illustrates the impacts of global warming and climate change on water resources; it also presents the finding of investigating the climatic water balance and the hydraulic properties of sand dunes. Part IV (Chaps. 6, 7, 8, 9, 10, 11, 12, and 13) presents the results of investigating surface water resources: seasonal floods, springs and aflaj systems and groundwater resources; and limestone aquifers, ophiolite aquifer, gravel aquifers, sand aquifer and sand-and-gravel aquifer system. Part V (Chaps. 14 and 15) provides results of studies on the nonconventional water resources: desalinated water and treated wastewater. The results of investigat-

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5

ing evolution, the prospects and environmental impacts of production and usage of nonconventional water resources are presented. Part VI (Chaps. 16, 17, and 18) identifies the challenges facing water resources: drinking water sources, standards and quality and results of investigating groundwater pollution of various aquifers. Part VII (Chaps. 19, 20, and 21) deals with water conservation, conventional and modern water harvesting techniques and the positive impacts of application of modern irrigation technologies on water-resource conservation. Part VIII (Chaps. 22, 23, 24, and 25) describes the use of remote sensing, GIS, isotope hydrology and modeling techniques in water-resources investigations. Part IX (Chap. 26) analyzes water governance and provides recommendations for increasing coordination and improvement of integrated water-resource management. Part X (Chaps. 27 and 28) summarizes water resources and water demands and efforts to maximize resources and manage demands. The volume ends with conclusions that cover all the themes of this book. Chapter 1 summarizes the 28 chapters constituting this book. The introduction discusses the factors affecting water resources such as geomorphology and geology, climate and global warming and climate change. It also provides an inventory of conventional and nonconventional water resources, highlights the challenges facing water resources and suggests water-conservation strategies, such as water-­harvesting techniques and the management of agricultural water demand. Chapter 2 provides an overview of water resources in the world, Middle East and North Africa (MENA) region, Arab world and Gulf Cooperation Council (GCC) countries. Each of the above sections includes an inventory of available conventional (floods, rivers, springs, aflaj and groundwater) and nonconventional (desalinated water and treated wastewater) water resources. The chapter also discusses water demands, water challenges and the demographic trends. An overview on global water resources including the main conventional water body stored in oceans, covering the Antarctic, Arctic and glaciers of high-mountain peaks and water stored in great lakes, running in great rivers and or stored at variable depths in the ground. The water available for direct human use is mostly groundwater (96.80%), while lakes (3.18%) and rivers (0.02%) carry minor amounts. Nonconventional water resources are desalinated water and treated wastewater. The rapid increase of population has reduced the global per capita water share from 12,900 m3 in 1970 to 5926 m3 in 2014. The main global water challenges are the uneven distribution of water resources, water-quality problems, escalating demand and negative impacts of global warming and climate change on water resources. The MENA region is about 8% of the world’s area, inhabited by 5% of the world’s population, but has less than 1% of the Earth’s water. The number of countries suffering from water shortage is expected to reach 18 countries in 2025, most of them Arab. The annual per-capita water share in Yemen, Jordan, Bahrain, Libya, and most of the Gulf Cooperation Council (GCC) countries, including the UAE, is less than 200 m3. About 15% of the world population receives over 50% of their

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water resources from neighboring countries, and many areas have started witnessing disagreements around water shares. The annual renewable, conventional water resources in the Arab region are estimated at 338  Bm3: 296  Bm3 surface water; 42  Bm3 groundwater recharge; and 15,000 Bm3 of nonrenewable water resources. In 2035, the per capita water share in the Arab region is predicted to reach 464  m3. The water challenges in the Arab region are over-exploitation of groundwater resources, lack of integrated water management, natural variability, lack of cooperation and coordination in development and management of shared water resources, water pollution and negative impacts of global warming and climate change on water resources. The share of the GCC countries of the total water resources in the Arab region is 4.6%. The total water resources in the Arabian Gulf countries between 1988 and 1997 reached 10.31 Bm3, including 8.00 Bm3 of conventional and 2.31 Bm3 of nonconventional resources, while water demand is expected to reach about 32.23 Bm3 by 2025. The per capita share of available water resources in the GCC countries is less than 250  m3/year, while the per capita water consumption in the region is 1035 m3/year. The main water challenges include reduction of non-revenue water, management of industrial water and wastewater, increasing water usage and policy reform in agricultural sector. Chapter 3 deals with the geomorphology and geology and their influence on surface and groundwater resources. Geomorphic features control surface water and determine the directions of flood flows, while the geologic setting dictates the distribution aquifers and confining units. Geologic structures may either block the passage of water or create preferential, natural passways acting as conduits accelerating water movement in many areas. The major geomorphic features in the UAE include: the eastern mountain ranges, gravel plains surrounding the mountains on the east and west, sand dunes, sabkhas, drainage basins and coastal areas. The low porosity and hydraulic conductivity of the rock-forming mountains coverts most of the rain falling on these mountains into surface runoff. The runoff water moves rapidly towards the gravel plains in the east and west, turning them into the most important, renewable, freshwater aquifers in the country. Sand dunes cover most of ​​the Western Region stretching between the western gravel plains in the east and the sabkha deposits along the Arabian Gulf in the west. The coastal areas include tidal flats and coastal sabkhas. The inland sabkhas occupy topographic depressions between sand dunes and act as areas of groundwater discharge. Despite the absence of surface-water resources such as rivers and lakes, dry drainage basins interrupt the continuity of rock outcrops and gravel plains through a network of dry drainage basins which may carry water during the rainy seasons. The drainage basins in mountains are represented by dense trellis and rectangular patterns because of the differences in lithology and geologic structure, while the drainage basins in gravel plains are characterized by dendritic and braided patterns because of the homogeneity of the plains’ sediments. This chapter also describes the geologic conditions, stratigraphic sequence and the hydrogeologic characteristics of various formations in terms of their relation-

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ship to water. Most of the surface area of the UAE is occupied by two main depositional basins; Ras Al Khaimah basin in the north and east and Rub’ al Khali basin in the south and west. The stratigraphic sequence in the UAE ranges in age from the Devonian Period of Paleozoic Era to the Quaternary Period. The Quaternary sediments cover most of the Western Region in the UAE. The rock sequence in Ru’us Al Jibal Mountains extends between the Permian and Early Triassic ages and represents the main aquifer in Wadi Al Bih basin at Ras Al Khaimah Emirate. The Dammam Formation of the Eocene age represents the main aquifer in the vicinity of ​​Jabal Hafit in the Al Ain area. The gravel deposits and sand dunes of the Quaternary age represent the most important aquifer in the UAE. The chapter also discusses the surface and subsurface geologic structures affecting, directly or indirectly, surface water and groundwater resources. These structures include Ru’us Al Jibal, the Dibba zone, the Wadi Ham line, the Hatta zone, Jibal Al Fayah and Hafit in the Eastern Region, as well as subsurface structures in the Western Region of the UAE. Chapter 4 discusses the climatic conditions in the UAE, which is one of the key determinants of the hydrogeologic conditions in the country. Coincidentally, rainfall scarcity due to high natural evaporation is the main cause of the prevailing drought and lack of surface water resources, such as rivers and lakes. The scarcity of rain leads to minimal recharge of aquifers and groundwater depletion. The average daily sunshine in the UAE is 10 h, and the air temperature can reach 50 °C during the summer. The relative humidity varies between 20% in the Liwa oasis and 90% in coastal areas. The two principal wind systems affecting the climate are the winter cyclonic depressions, which descend the Arabian Gulf from the north and northwest and give rise to the cold northwesterly “Shamal” (Arabic word meaning north) airflow; and the summer monsoonal low develops over the Rub’ al Khali (Arabic term meaning empty quarter) desert. The “Shamal” winds affect the western coastal cities of Abu Dhabi, Dubai, Sharjah, Ajman, Umm Al Quwain and Ras Al Khaimah, while the summer monsoon affects the Eastern Region’s cities of Fujairah, Khor Fakkan, Dibba and Kalba. The annual evaporation rates are 20–30 times higher than the mean annual rainfall, but the use of monthly and daily records of rainfall is more realistic in evaluating groundwater recharge. The analysis of climatological data for the period 1976–2015 indicates that February is the rainiest month, while July is the driest month and has the highest evaporation rate. This chapter also discusses global warming and climate change and their negative impacts on water resources. These impacts are induced by variation of temperature and rainfall and cause decline of aquifer recharge, shortage of irrigation water, aquifers’ depletion and increasing groundwater and soil salinities. Chapter 5 studies the climatic water balance and analyzes the relationship between rainfall and potential evapotranspiration (PET) in the Al Ain area. The study results distinguish water-surplus areas from water-deficit ones. In water-­ surplus areas, part of rainwater can contribute to groundwater recharge. In contrast, water-deficit areas suffer from severe drought because the monthly PET rates greatly exceed monthly rainfall. Results of grain-size analysis and infiltration capacity (Ic)

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measurements were used for determining the hydraulic properties of gravel plains and sand dunes around Al Ain City. The study was a trial to understand the mechanisms of groundwater recharge in the sand dunes and gravel plains, which cover about 80% of the surface area of the UAE. The study indicated that the percentage of runoff from rainfall is 18% in the eastern mountain ranges and 3% in the Jabal Hafit area. The results of this study can help in identifying areas for aquifer-storage recovery (ASR) projects, which has already started in more than one emirate. In this regard, the gravel plains and sand dunes are the most favorable sites for artificial groundwater recharge, especially where these aquifers are severely depleted due to over-exploitation of groundwater. Chapter 6 provides detailed discussion of seasonal floods in the Eastern Region of the UAE and analysis of rainfall-runoff relationship, flood volumes and rainfall amounts that may lead to surface runoff. It also deals with classification of dry drainage basins in the eastern UAE and their flood potential. It investigates flash floods, flood hazards and the flood potential of various drainage basins. The chapter discusses the role of groundwater-recharge dams in harvesting flood water, which used to drain into the Gulf of Oman along the east coast, the Arabian Gulf in the northwest and desert plains in the west and southwest. Flood water used to cut off roads and destroy farms and houses, but now, a good part of this water is harvested by a large number of recharge dams. It is estimated that 120 million m3 of flood water are annually harvested by recharge dams built in main wadis. The drainage basins in the UAE need detailed investigation to help set priorities of site selection for future recharge-dam projects. Chapter 7 includes discussion of the geology, hydrogeology and hydrochemistry of the few permanent springs in the UAE. It also provides evaluation of the suitability of spring water for irrigation, recreation and therapeutic uses. These springs are located along definite structural elements, within various drainage basins, at variable topographic elevations and drain different rock types, which affect the springs’ discharge, water chemistry and water quality. Based on discharge rates, Bu Sukhnah spring ranked second and Khatt springs fourth in volume. The discharge of Khatt springs is directly related to rainfall, while the discharge rates of the Bu Sukhnah springs is not directly related to local rainfall. High spring-water temperatures (39 °C in Khatt north, 39.5 °C in Bu Sukhanah and 41  °C in Khatt south) are related to deep groundwater circulation or radioactive decay at depth, especially in the case of Bu Sukhnah spring. Chapter 8 investigates the geologic setting, hydrogeology, water chemistry and water quality of aflaj systems in the UAE, which provide a limited amount of renewable water. Aflaj systems are a part of the cultural heritage in the UAE, and their water has been used for all purposes in the past, but recently, aflaj water is mainly used for irrigation in the northern and eastern parts of the country. Despite the small volume of annual aflaj discharge, which varies between nine and 31 Mm3, representing 3–10% of the total water used in the UAE, aflaj water is renewable and their discharge can be increased by maintaining their channels and tunnel systems. This chapter also discusses aflaj origin, history, design, management, water quality and suitability for irrigation.

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Chapter 9 discusses the results of investigation on the limestone aquifers in the Wadi Al Bih basin, Jabal Hafit and the Western Region of the UAE. The Wadi Al Bih limestone aquifer is the main source of water in Ras Al Khaimah City. For this reason, the hydrogeology, hydrogeochemistry, isotope hydrology and water quality of the aquifer were studied in detail over a long period of time. The geology and hydrogeology, hydrogeochemistry and isotope hydrology of the Dammam limestone aquifer in the Jabal Hafit area were also investigated. The aquifer there produces about 7.7 Mm3/year of hot, salty water of high therapeutic value. The area has been developed as a touristic site and for recreation. In the Western Region of the Abu Dhabi Emirate, the limestone aquifers of Dammam, Umm Er Radhuma and Simsima, ranging in age from Upper Cretaceous to Eocene, are highly saline with salinities varying between 70,000 and 230,000 mg/L. Water from these aquifers is injected into oil fields to maintain reservoir pressure. Chapter 10 deals with the ophiolitic aquifer, which is a low productivity aquifer, except in areas where the intensity of joints, folds, faults and fractures increase the secondary porosity (θ), hydraulic conductivity (K) and productivity of the aquifer. The aquifer’s average transmissivity (T) and specific yield (Sy) are 776 m2/day and 0.24, respectively. The chapter also discusses the linear features and their geologic and hydrogeologic influence on groundwater levels, chemistry, quality and use. The groundwater quality in the ophiolite aquifer is good because its matrix is hardly soluble in water. But, the water salinity increases with increasing depth due to lower density of fractures, smaller size of cracks and the slow velocity of groundwater flow. Three structural zones affect the ophiolite aquifer: the Dibba zone, Wadi Ham line and Hatta zone. These zones do not only affect groundwater resources but also control the distribution of urban centers, farms, water-well fields and sabkha deposits. Chapter 11 discusses the gravel aquifers, which store the largest reserve of fresh, renewable groundwater in the country. These plains bound the eastern mountain ranges on the east and west and are distinguished into two aquifer types: the eastern gravel aquifer and the western gravel aquifer. The eastern gravel aquifer extends from Dibba in the north to Kalba in the south. Groundwater water in this aquifer is the main source of water used for agricultural, industrial and domestic purposes. Irrigation consumes about 90% of water resources in the eastern coastal region because of the intensity of farming and agricultural activities. However, excessive groundwater pumping over the past four decades has dramatically lowered groundwater levels, degraded water quality and increased salt-water intrusion in many areas. The western gravel aquifer extends between Ras Al Khaimah in the north and Al Ain area in the south. The aquifer covers the area between rock outcrops of the eastern mountain ranges and sand-dune fields in the west. The aquifer also extends under the sand dunes, as buried alluvial channels, representing aquifers of high water quality and productivity. Chapter 12 offers a detailed study of the Quaternary sand-dune aquifer in Liwa and Bu Hasa areas. The study provides in-depth discussion of hydrogeology, groundwater chemistry and isotope hydrology of the aquifer. Two fresh-water

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mounds belonging to the Liwa Quaternary sand aquifer represent relics of an old, large aquifer that occupied the northwestern part of the Liwa area during Pleistocene– Holocene pluvial periods. Another, but smaller, freshwater mound exists between Habshan Station and the Bu Hasa oilfield. The striking similarity of hydraulic properties, hydrogeochemistry and natural isotopes of the groundwater at Liwa and Bu Hasa permitted dealing with the aquifers in both areas as a single aquifer named by the authors the “Liwa Quaternary sand aquifer”. The depth to groundwater varies between a few meters and 50 m at Liwa oasis, and from 24 to 52 m at Bu Hasa oilfield. The aquifer’s saturated thickness ranges from 75 m at the Shah oilfield to 175 m at the Bu Hasa oilfield; hydraulic conductivity (K) is 2.3–8.5 m/day, transmissivity (T) varies between 200 and 650 m2/day; and specific yield (Sy) is 0.1–0.3. Although sand dunes cover 74% of the total area of the UAE, the Liwa Quaternary sand aquifer is the least studied in the country and needs additional detailed investigation. Chapter 13 covers discussion of the sand and gravel sediments as a single aquifer system because most of the hydrogeological studies confirmed that the sand and gravel sediments experience hydraulic continuity, and in many areas it is difficult to distinguish the gravel from the sand aquifers. Therefore, this chapter summarizes the findings regarding the geologic setting, hydrogeologic characteristics, groundwater chemistry and isotope hydrology of the sand gravel aquifer system. The depths to groundwater, hydraulic heads and groundwater chemistry suggest the presence of three groundwater flow systems. The presence of these systems affect water chemistry and quality in the aquifer. Local groundwater flow systems contain water of brief residence times, low salinity and good quality. Intermediate groundwater flow systems discharge into inland sabkhas, where water is generally brackish and has a moderate residence time. Regional groundwater flow systems discharge into coastal sabkhas; water in these systems is highly saline, has a long residence time and discharges near the shoreline of the Arabian Gulf in the west. The measurements of stable and radioactive isotopes indicate that the age of groundwater in the sand and gravel aquifer system increases from east towards west, in the direction of groundwater flow. Isotopes also confirmed the hydraulic connection between the gravel aquifer in the east and the sand aquifer in the west, without the possibility of defining a clear boundary between the two units in many areas. Chapter 14 discusses water desalination in the UAE in terms of the technologies used and the evolution of the industry itself. The chapter focuses on the increasing role of desalinated water in bridging the gap between limited conventional water resources and growing demand for water. The chapter also investigates the advantages and disadvantages of the desalination industry and its impacts on marine and terrestrial environments. In addition, the chapter discusses approaches for alleviating the negative impacts of the desalination industry and proposes an innovative approach for brine recycling and achieving zero brine discharge. Chapter 15 deals with treated wastewater as an additional, renewable supply of water and its major role in easing pressure on conventional water resources in the

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future. The annual volume of treated wastewater has greatly exceeded the annual amount of groundwater recharge. The role of treated wastewater is likely to increase in the future because of continuous urban expansion and extension of drainage networks to serve ongoing urban development. There are 78 wastewater treatment plants, producing 711  Mm3 in 2015. Two-­ thirds of treated wastewater is used for irrigation and landscaping, and a third is discharged either into the sea or the desert. This chapter also discusses the advantages and limitations of using treated wastewater and addresses the evolution wastewater reuse in the UAE and presents two case studies of wastewater treatment in Abu Dhabi and Ras Al Khaimah emirates. Chapter 16 addresses the problems facing conventional water resources, including seasonal floods, permanent springs, aflaj systems and groundwater stored in various aquifer systems. The chapter also deals of problems facing nonconventional water resources, including desalinated water and treated sewage water. The problems facing surface-water sources are pollution from surface sources, inadequate quality for domestic uses, scarcity and absence of recent recharge. The groundwater resources receive limited recharge from rain in the northern and eastern parts of the country and are generally suffering from scarcity, water logging and unsuitability for irrigation and pollution. The chapter discusses the depletion of aquifers throughout the country, increasing groundwater salinity, water hardness, deterioration of groundwater quality, dryness of a large number of wells and the salt-water intrusion problem. The chapter also addresses aquifers’ pollution caused by natural sources and human-related activities, particularly agriculture and oil industries. The thermal desalination plants suffer from scale formation and precipitation, while the reverse-osmosis plants’ membrane face fouling and corrosion. Discharge of reject brines into coastal areas leads to negative physical, chemical and biological impacts on marine environment, while uncontrolled disposal of reject brines from inland desalination plants, leads to serious pollution problem to fresh groundwater resources. The problems facing reuse of treated wastewater are mainly psychological, such as fear of diseases, unrest and belief that this water is unsafe, irrespective of the level of treatment. However, there is a direct relation between certain diseases and the use of treated sewage water for irrigation. Conventional wastewater treatment techniques do not completely remove harmful pathogenic Bactria and viruses and leads to accumulation of heavy metals. Chapter 17 offers an integrated study of water used for drinking and domestic purposes in the UAE. About 400 samples from various different sources, including bottled water, desalinated water and groundwater used for drinking and domestic purposes were analyzed in the context of this study. The study compared the concentrations of major, minor and trace chemical constituents in studied water with the national and international recommended and maximum permissible limits for drinking water. Results of this study revealed a wide variation in concentrations of major, minor and trace inorganic chemicals in drinking and domestic water. Some brands of bottled water are almost free of trace ions and minor constituents, but

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1  Introduction to Water Resources of the United Arab Emirates

natural groundwater used might have concentrations higher than the WHO recommended limits for drinking water. The main cause for this variation is related to the different water sources and the large number of companies working in production and distribution of drinking and domestic water. The current controls on domestic water quality in some areas, namely conformance of pH and electrical conductivity measurements with prescribed ranges of values, are inadequate. These two parameters are not enough to judge if water is suitable for drinking or not, and some consumers may receive domestic water of uncertain quality. Chapter 18 describes case studies of groundwater pollution of various aquifer systems in the UAE. Recent investigation of Wadi Al Bih limestone aquifer in Ras Al Khaimah Emirate revealed that the aquifer is highly sensitive to urban and agricultural development, and several wells, in the Wadi Al Bih and Al Burayrat areas, were reported to contain Coliform bacteria. Remote sensing (RS) and GIS studies showed that intensive agriculture, human activities and dissolution of carbonate rocks in the Al Ain area are contributing to the degradation of groundwater quality in the western gravel aquifer in the Eastern Region of the UAE. Major ions chemistry and nitrate isotopes identified the sources of nitrate pollution of the Liwa Quaternary sand aquifer as animal waste (10%), soil nitrogen (25%) and fertilizers (65%). The study of the roles of the prevailing climate, geology and hydrogeology in groundwater pollution of the Quaternary sand and gravel aquifer in Ajman area identified point and nonpoint sources of pollution, related to natural conditions and human activities. Based on the results of field studies and chemical analyses of collected groundwater samples, recommendations were made for pollution control. Chapter 19 discusses water conservation through the application of integrated water- resources management (IWRM) approach, through community practices and technological solutions. Each emirate has at least a law or an Amiri Decree regulating the drilling of water wells and groundwater extraction and protection. In addition, the government has built more than 130 dams capable of storing 120 m3, as well as planning to build 68 additional dams in the future. Recharge dams conserve flood water, enhance groundwater recharge and protect homes and farms against the danger of flash floods. The chapter also identifies water use in the UAE and provided suggestions for reducing water losses. The Abu Dhabi Food Control Agency (ADFCA) has provided a number of initiatives for reducing water wastage in the agricultural sector, including reduction of water consumption in farms, use of treated wastewater for irrigation, promoting good agricultural practices, phasing out Rhodes cultivation, improving irrigation networks, the application of smart irrigation systems, improvement of soils and expansion of greenhouse agriculture. The chapter also describes efforts for raising public awareness of water issues and mechanisms for dealing with water problems on individual and society levels. Chapter 20 describes the evolution of water-harvesting techniques from conventional methods to state-of-the-art technologies. Conventional water harvesting techniques include barriers, habisas, ponds and aflaj systems, while the modern

1  Introduction to Water Resources of the United Arab Emirates

13

water-harvesting technologies comprise subsurface dams, cloud seeding, artificial recharge and aquifer storage and recovery (ASR). The old water-harvesting techniques are not yet obsolete and are still in use along with the most recent technologies. This chapter also discusses recharge dams and their role in aquifers’ recharge and improvement of groundwater quality, artificial recharge and the ASR projects in Abu Dhabi and Sharjah emirates. Assessment of efficiency of recharge dams revealed the dams diverted 20% and 40% of the reservoirs’ water to aquifer recharge. The recharge efficiency can be enhanced by removing 10–15 cm of accumulated silt on wadi floors to expose the gravel top layer. The UAE has two pilot ASR projects in the Abu Dhabi (Liwa and Shuwaib areas) and Sharjah (Nezwa area). Both projects utilize surplus desalinated water during the winter for injection in depleted aquifer systems and subsequent retrieval during high demand. Chapter 21 addresses the introduction and development of modern irrigation techniques in the UAE that reduce pressure on the limited conventional water resources, especially groundwater. The wide application of groundwater for irrigation and exploitation of the main aquifer systems in excess of natural recharge has led to serious depletion and salinity problems all over the country. The chapter discusses modern irrigation techniques, such as drip, sprinkler and bubble irrigation, which replaced traditional irrigation methods in 90% of farmland in the country and saved considerable amounts of irrigation water and increased crop productivity. Biosaline agriculture could contribute effectively to integrated water-resources management because it enables the use of marginalized resources, namely, salt water and saline soils (sabkha-dominated areas). The International Center for Biosaline Agriculture (ICBA) in the UAE, which is unique of its kind in the region, is searching local and foreign varieties of crops for identification of salt-tolerant species. ICBA is also active in areas of water conservation and reuse, increasing irrigation efficiency, water storage and the use of seawater for production of biofuels. The chapter also discusses protected agriculture in greenhouses, aquaculture and hydroponics, as well as the environmental impacts of agriculture. Sustainable farming of organic products is a promising alternative for conventional crops because it meets the growing market needs and receives full support from the government. Chapter 22 discusses the use of remote-sensing (RS) techniques, in addition to field work and laboratory analyses, to measure the hydraulic properties of sand dunes and interdune areas in the southwest Al Ain Region of Abu Dhabi Emirate. The RS techniques were used for identification of groundwater quality, recharge and discharge areas and detection of fluctuation in groundwater levels. The chapter presents the results of treatment and processing of satellite images, such as image enhancement and extraction of information on the distribution of infiltration rates and uniformity coefficients in sand dunes and interdune areas and calculation of the amount of natural evaporation. The application of RS techniques, uniformity coefficients and infiltration rates enabled the classification of sand dunes within the study area into three classes exhibiting increasing sand sorting and fluid-transmitting capacity (θ, K and T) for

14

1  Introduction to Water Resources of the United Arab Emirates

the east towards west. The RS technique was also used for classification of interdune areas, according their soil-moisture content. The observed seasonal changes in these classes reflect fluctuation of groundwater table in the sand and gravel aquifer system. The RS technique was also applied for calculation of the amount of natural evaporation from standing water and near-surface groundwater in the investigated area. Chapter 23 presents the results of a study conducted by the authors to follow up and update the hydrogeologic investigation made by the Ministry of Agriculture and Fisheries (now: Ministry of Climate Change and Environment) in cooperation with the Japan Foundation for International Cooperation (JICA) in the Al Dhaid area, eastern Sharjah Emirate. In this study, Geographic Information Systems (GIS) techniques, geophysical data, hydrogeologic investigation and the results of chemical analyses of groundwater samples were used for soil classification, identification of major geologic structures and hydrologic units, analysis of groundwater quality and assessment of the suitability of groundwater for various uses. The western gravel aquifer within Al Dhaid area receives recharge from rains falling on the western foothills of the eastern mountain ranges in the UAE. For this reason, it is recommended to establish a groundwater protection zone in the upstream area to maintain the present supply of fresh recharge water feeding groundwater in the Al Dhaid area. The results of this investigation contribute to understanding of the factors affecting groundwater flow, recharge and potential. Chapter 24 presents a summary of the results of an isotope hydrology survey covering the whole area of the UAE. The study was intended to identify the sources and properties of winter and summer rains, sources and ages of groundwater in various aquifers an to determine the source(s) of increasing groundwater salinity in various aquifers and the source groundwater pollution in Liwa Quaternary sand aquifers in the Western Region. The chapter includes the results of long-term scientific cooperation project conducted jointly by the International Atomic Energy Agency (IAEA) and the Ministry of Environment and Water. The project involved the use of environmental isotopes for the assessment of the efficiency of some dams in groundwater recharge, identification of groundwater-flow direction and the calculation of groundwater flow velocities in shallow and deep aquifers and the determination of the origin and age of groundwater in some areas. Chapter 25 presents the results of groundwater flow and solute-transport models used for simulating hydraulic heads and identifying the source(s) of increasing groundwater salinity in the Wadi Al Bih limestone aquifer in Ras Al Khaimah Emirate. The models were prepared with the use of Visual Modflow Package, along with available hydrogeologic and hydrogeochemical data for water-well fields in Wadi Al Bih basin. The model simulated the aquifer’s pre-development conditions and predicted hydraulic heads in the aquifer under various water-development scenarios. Other modeling efforts include a finite element model used for identification of the source of dissolved benzene in the Liwa Quaternary sand aquifer at Bu Hasa area, a numerical model used for forecasting water demand in Umm Al Quwain

1  Introduction to Water Resources of the United Arab Emirates

15

Emirate, groundwater flow and solute transport models for assessment of the effectiveness of Wadi Tawiyean on groundwater recharge and salt-water intrusion in the eastern gravel aquifer in Wadi Ham area at Fujairah Emirate and a three-layers, 3D groundwater-flow model for simulating groundwater flow and salinity distribution in the western gravel aquifer in the Al Wagan area, Al Ain Region of Abu Dhabi Emirate. Chapter 26 discusses water governance in the UAE and reports that the country follows a decentralized system in managing the agencies responsible for water resources in various emirates. The institutions and regulations governing natural conventional water resources are conducted on the level of each emirate, while the national policies, strategies and legislations are retained within the federal government. Therefore, emirates are directly responsible for managing their natural water resources, while the Ministry of Energy (MOE) is mainly responsible for decision making related to water issues at the national strategic level. The nonconventional water resources (desalinated water and treated wastewater) are the property of producers. The operations and management of these water sources take place at the emirate level, with a variety of organizations involved, ranging from municipalities to private companies. This current water-governance system causes inflation in the state budget and overlaps in decision making for the production and use of water, as well as differences in design and implementation of water projects. Therefore, there is a need for a federal water law and a federal water authority, in order to ensure that water supply and use are planned and regulated at the federal level, as well as implemented and organized at the emirate’s level. Chapter 27 provides a general summary of water resources and water demand in the UAE.  The country relies on nonconventional water resources, in addition to conventional ones, in order to meet the growing needs for water. The conventional water resources include seasonal floods, springs, aflaj systems and groundwater. The nonconventional water resources are desalinated water and treated wastewater. There will be a steady increase of water-resources usage and demand during the period 2015–2025, where the production of desalinated water will be almost doubled and the industrial sector demand could reach 1 Bm3. Improvement of water-­ resources management can lead to water conservation, maintenance of better quality water and restoration of deteriorating aquifer systems. The use of advanced irrigation technologies, construction of groundwater-­ recharge dams, and growing salt-tolerant crops are suitable agricultural approaches. Development of human resources is a priority to prepare trained national experts in water-related fields. Establishment of data banks and the application of remote sensing, GIS, groundwater modeling and isotope hydrology techniques are powerful water-resources management and decision-support tools. Chapter 28 is a summary of the book and presents the main conclusions of the authors’ investigations described in detail in this volume.

Chapter 2

Overview on Global Water Resources

Abstract  The oceans are the Earth’s primary conventional storage body for water, including the Antarctic, Arctic and glaciers of high mountain peaks. The groundwater represents 29.9%, and only 0.26% of the total freshwater is stored in lakes, rivers and reservoirs while 0.94% is soil moisture. The water available for direct human use comprises 96.80% groundwater, 0.02% river water and 3.18% in lakes, while desalinated water and treated wastewater are the main nonconventional sources of water. The rapid increase in population between 1970 and 2014 lowered the per capita water share from 12,900 m3 in 1970 to 5926 m3 in 2014. The main global water challenges are the uneven distribution of water resources, water-quality problems, escalating demands and climate change. The MENA region is about 8% of the world’s area, inhabited by 5% of the world’s population, but its water resources do not exceed 1% of the Earth’s water. The number of countries suffering from water shortage is expected to reach 18 in 2025. The annual per capita water share is > 2000 m3 in Iran and Iraq and 3.6 million Ha; out of proportion; India: > 1 million Ha

Untreated & diluted

Treated

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Area (’000 ha)

Fig. 2.7  The world usage of treated and untreated wastewater for irrigation. (After Lautze et al. 2014)

2.1  Global Water Resources

27

Table 2.7  Application of treated wastewater for irrigation in 30 countries Country USA Mexica Guatemala

Amount of treated wastewater used for irrigation (m3/day) > 573,000 > 573,000 < 24,000

Brazil Peru Chile Argentina UK France Spain Germany Italy Poland Turkey Iran

< 24,000 207,000–390,000 207,000–390,000 24,000–207,000 24,000–207,000 < 24,000 > 573,000 24,000–207,000 24,000–207,000 < 24,000 24,000–207,000 207,000–390,000

Country Syria Jordan Saudi Arabia Oman UAE Egypt Libya Tunisia Morocco S. Africa Namibia China N. Korea Japan Australia

Amount of treated wastewater used for irrigation (m3/day) 207,000–390,000 24,000–207,000 > 573,000 24,000–207,000 207,000–390,000 > 573,000 24,000–207,000 207,000–390,000 < 24,000 24,000–207,000 24,000–207,000 > 573,000 207,000–390,000 > 573,000 > 573,000

After Dedercq and Condom (2015)

2.1.3  Water Demands Asia consumes 70% of the available water because it has most of the irrigated lands in the whole world, but, during the next decade, water consumption will increase at varying rates (Tables 2.8, 2.9, and 2.10).

2.1.4  Water Challenges 2.1.4.1  Demographic Drivers The fast population growth (Table 2.11), especially in developing countries, represents a great challenge to the availability of safe drinking water and the provision of adequate sanitation systems (UN 2007 and 2015). The water-shortage problem has to be tackled through a cross-sectorial approach involving public awareness and participation, education, agriculture and energy. In Africa and the Middle East, the population is still growing rapidly, whereas in Europe and East Asia, aging is rapidly increasing (Fig. 2.8).

28

2  Overview on Global Water Resources

Table 2.8  Water resources of the continents

Population (1000) 690,550 3,469,180 688,143 28,164 454,926

Total withdrawal by sector Municipal Industrial Agricultural TWWa km3/ km3/year km3/year km3/year km3/year year 3617 13.90 9.10 136.10 159.10 9385 142.40 203.8 1697.4 2043.7 2191 59.70 233.4 139.20 432.30 1680 8.90 0.40 6.00 15.40 3824 80.50 263.7 315.80 660

319,214

8789

Water resource

Continent Africa Asia Europe Australia North America south America

22.20

13.10

102.10

Rate of use to resources (%) 4.40 21.8 19.7 0.90 17.3

137.40 1.60

After Shiklomanov (2000) a TWW Total water withdrawal includes use of desalinated water and treated wastewater Table 2.9  Total water withdrawal per sector and per capita on various continents in 2006 Total freshwater Freshwater withdrawal withdrawal Agricultural TWWa Total (% of withdrawal km3/ km3/ IRWRb) per capita km3/year year % year 175 82 214 230 202 5 409 49 829 927 825 4 2035 81 2507 628 2376 20 73 22 333 455 331 5 11 60 18 657 18 2 2702 69 3902 593 3753 9

Total withdrawal by sector Municipal km3/ Continent year % Africa 28 13 Americas 135 16 Asia 228 9 Europe 72 22 Oceania 5 26 World 469 12

Industrial km3/ year % 11 5 285 34 244 10 188 57 3 15 731 19

After UN (2014) a TWW Total water withdrawal includes use of desalinated water and treated wastewater b IRWR internal renewable water resources

Table 2.10 Annual per capita water share in m3/year for different continents: Trends and projections Continent Africa Americas Asia Europe Oceania World After UN (2014)

Annual per capita water share (m3/year) 2000 2010 2030 4854 3851 2520 22,930 20,480 17,347 3186 2845 2433 9175 8898 8859 35,681 30,885 24,873 6936 6148 5095

2050 1796 15,976 2302 9128 21,998 4556

2.2  Water Resources in the Middle East and North Africa Region

29

Table 2.11 The actual world population in 2015  in various continents and the predicted populations until 2030 Continent Africa Asia Europe LAACa N. America Oceania World

Population projection (million) 2015 2020 2025 1,166,239 1,312,142 1,467,973 4,384,844 4,581,523 4,748,915 743,123 743,569 741,020 630,089 661,724 690,833 361,128 375,724 389,939 39,359 42,066 44,734 7,324,782 7,716,749 8,083,413

2030 1,634,366 4,886,846 736,364 716,671 403,373 47,317 8,424,937

Urban population (%) 2015 2020 2025 41.1 43.2 45.3 47.6 50.5 53.1 73.8 74.9 76.1 80.2 81.5 82.5 83.1 84.1 85.0 70.8 70.9 71.1 53.9 56.0 58.0

2030 47.7 55.5 77.4 83.4 85.8 71.4 59.9

After UN (2015) a LAAC Latin America and Caribbean

100 2005

Percentage

80

2030

60 40 20 0

World

Africa

Asia

Eurpe

North Latin America America and Caribbean

Oceania

Fig. 2.8  The growth of the percentage of people living in urban areas around the globe in 2005 and 2030. (After UN 2007)

2.2  W  ater Resources in the Middle East and North Africa Region The MENA region is semi-arid to extremely arid except the coastal strip along the Mediterranean Sea. Humid to subhumid conditions prevail in the high mountains in the northern and southern parts of the region (ESCWA (Economic and Social Commission for Western Asia) 2001; ESCWA 2005, 2007). The northern mountainous areas of Lebanon, Palestine, Iraq, Jordan and Syria receive rainfall during the period October–April, with higher precipitation from December to February (1000–1500 mm/year). The southern part of the Arabian Peninsula receives rainfall between 500 and 1000 mm/year during the period May–August in the highlands, causing heavy rain-

30

2  Overview on Global Water Resources

Fig. 2.9  Mean annual rainfall in MENA region. (After Terink et al. 2013)

storms and flash floods. However, in the southwestern escarpment of Yemen, annual rainfall as high as 1500 mm/year is common. The larger part of the Middle East region receives precipitation far below 100 mm/year (Fig. 2.9).

2.2.1  Conventional Water Resources The average per capita water share in MENA region is close to the United Nations water poverty line (1000  m3/capita/year). But, country averages range from less than 200 m3/capita/year in the GCC countries, Bahrain, Jordan, Libya and Yemen to more than 2000 m3/capita/year in Iraq and Iran (Fig. 2.10). In addition to the prevailing arid climate and scarcity of rain, international water, water carried by permanent rivers from outside the borders, such as in the Euphrates and Tigris and Nile represents an additional challenge to countries of the d­ ownstream segments of these rivers, such as Iraq, Syria and Egypt. Figure 2.11 shows that virtual water exhibits large variations from one country to another. Based on water management challenges, the World Bank (2007) classified the MENA countries into three categories, including arid, hyper-arid and transboundary water (Fig. 2.11). While arid countries may have little amounts of renewable water sources, hyper-arid countries depend on desalinated water and treated wastewater sources. These countries have to manage their aquifer systems in order to avoid depleting their water resources. In transboundary countries, more than one-half of their annual renewable surface water comes from outside their borders, and so they are highly dependent on international water sources. According to the World Bank (2007) and UNDP (2013), Figs.  2.12 and 2.13 show water resources in the MENA countries in Bm3. Table 2.12 illustrates that five Arab countries import water in the form of food supplies. This water is known as virtual water.

2.2  Water Resources in the Middle East and North Africa Region

31

Iraq Iran Syria Lebanon Morocco Egypt Tunisia Algeria Djibouti Oman West Bank and Gaza Yemen Jordan Bahrain Libya Saudi Arabia Qatar United ARab Emirates Kuwait

0

500

1,000

1,500

2,000

2,500

3,000

3,500

meters /inhabitant/year 3

Fig. 2.10  The annual per capita share of natural water resources in the MENA region. (After the World Bank 2007)

100

percenet

80 60 40 20

arid virtual water

hyper-arid nonrenewable ground water

external renewable

Ira Eg q yp t Sy ria

Le Ira ba n M non or oc Tu co ni s A ia lg er U ni i D te jib a d ou A ra ti b Em Sa ud irat i A es ra b Jo ia rd W an es Li tB b an Ba ya h k an rai d n G a Ye za m K en uw ai O t m an Q at ar

0

transboundary water internal renewable

Fig. 2.11  Share of water available or used, by source, in the MENA region. (After World Bank 2007)

32

2  Overview on Global Water Resources

140

109 meters3

120 100 80 60 40 20

A

B

lg er ah ia ra D in jib ou Eg ti yp t Ira n Ir Jo aq rd a K n uw Le ai ba t no n Li M by or a oc c O o m an Sa ud Qa t i A ar ra U bi ni a te Sy d W A r i es ra Tu a ni tB b an Em sia i k r an ate d s G a Ye za m en

0

internal renewable

external renewable

nonrenewable groundwater

Fig. 2.12  Volume of water resources available, by source, in MENA region. (After the World Bank 2007)

100

percenet

80 60 40 20

B

A

lg er ah ia ra D in jib ou t Eg i yp t Ira n Ira Jo q rd a K n uw Le ait ba no n Li by M or a oc co O m an Sa Q ud ata iA r ra bi U a ni Sy te d r i a W Ar T es ab un tB Em isia an k irat an e d s G az Ye a m en

0

virtual water

nonrenewable ground water

external renewable

Fig. 2.13  Percentage of water resources available, by source, in MENA region. (The World Bank 2007)

2.2.1.1  Surface Water According to CEDARE (2006), surface water is one of the main water sources in the MENA region, while rainfall exhibits wide variation in time and space. UNDP (2013), on the other hand, mentioned that the Nile, Tigris and Euphrates are the main permanent rivers in the MENA region.

2.2  Water Resources in the Middle East and North Africa Region

33

Table 2.12  Water available or used by source in MENA region

Country Yemen Palestine UAE Tunisia Syria Saudi Arabia Qatar Oman Morocco Libya Lebanon Kuwait Jordan Iraq Iran Egypt Djibouti Bahrain Algeria Total

Water available by source (Bm3/year) External Internal Non-­ renewable renewable renewable water water groundwater resources Area (km2) resources 527,970 2.70 0.00 1.30 6015 0.80 0.00 0.00 83,600 0.70 0.00 1.60 163,610 4.20 0.40 0.70 185,180 7.60 19.3 0.00 2,149,690 3.20 0.00 17.8

Water dependency ratio (%) 0.00 3.00 0.00 8.70 72.4 0.00

Virtual water 1.60 2.20 4.20 4.10 −4.1 13.1

11,610 309,500 446,550 1,759,540 10,450 17,820 89,320 4,352,400 1,648,000 1,001,450 23,200 765 2,381,740 15,168,410

3.50 0.00 0.00 0.00 0.00 0.80 100 27.2 60.8 96.9 0.00 96.6 3.60 –

0.30 1.40 5.80 1.40 2.00 1.40 5.00 1.40 6.80 18.9 0.10 0.50 10.9 77.0

0.20 1.00 29.0 0.70 4.80 0.30 0.70 35.2 128.5 4.90 0.30 0.10 13.9 238.8

0.00 0.00 0.00 0.00 0.00 0.00 0.20 40.2 9.00 56.5 0.00 0.10 0.40 126.1

0.20 0.20 0.00 3.70 0.00 0.30 0.20 0.00 0.00 0.80 0.00 0.10 1.70 28.6

The World Bank (2007)

2.2.1.2  Groundwater The World Bank (2007) pointed out the presence of large aquifer systems in the Arabian Peninsula and North Africa (Fig. 2.2). These aquifers store substantial nonrenewable groundwater reserves

2.2.2  Nonconventional Water Resources 2.2.2.1  Desalinated Water GWI (2010) and Nair and Kumar (2012) mentioned that some MENA countries adopted water desalination since the early 1950s, such as Kuwait. Subsequently, several countries started building desalination plants to fill the gap between the limited available freshwater resources and growing demands. In 2016, the MENA share

34

2  Overview on Global Water Resources

increased to approximately 70% of the desalination capacity. Statistics of the World Bank (2012) showed that nine countries in the MENA region are among the 15 largest countries with conventional desalination plants in the world. Desalinated water has become a main source of water in the Gulf region and has proven to be a practical solution for the water-shortage problem, by filling the gap between the limited natural resources and the escalating demand for water. The number of MENA countries, particularly the GCC countries, depending on desalinated water is increasing (Fig. 2.14). Global warming and climate change are expected to affect water resources in negatively due to increasing temperatures and decreasing rainfall rates in the MENA region. This will widen the gap between available water resources and water demand and makes desalinated water and treated wastewater integral parts of the future water supply for all purposes. A review of the global desalination market in 2016 indicated that reverse-osmosis technology accounts for 73% of the capacity of newly installed desalination plants (Fig. 2.15).

Fig. 2.14  Share of national water demand in MENA countries met by desalination in 2010. (After the World Bank 2012)

2.2  Water Resources in the Middle East and North Africa Region

35

Fig. 2.15  The annual global growth of desalination by technology between 2006 and 2016. (After the World Bank 2012)

2.2.2.2  Treated Wastewater The World Bank (2012) and Jeuland (2011) indicated that wastewater has a major role to play in easing pressure of expensive desalinated water and depleting aquifer systems. In addition, collection and treatment of wastewater in urban areas represent an environmental and health necessity. Treated wastewater can be used in restricted agriculture, landscaping and many industrial uses.

2.2.3  Water Demands Agriculture consumes more than 85% of groundwater withdrawn from the main aquifer systems, while the domestic uses rank second. As urban areas are developing at unprecedented rates, the current pattern of water consumption will change in the future. In the meantime, several MENA countries have recently boosted ­industrial production in order to improve their national economies, so industrial water demand will also increase in the future.

2.2.4  Water Challenges People living in the Middle East represent 5% of the total world population, but their water resources do not exceed 1% of the Earth’s water. The number of countries suffering from water shortage in the Middle East has increased from three

36

2  Overview on Global Water Resources

(Bahrain, Jordan and Kuwait) in 1955 to 11 countries in 1990, and the number is expected to 18 countries in 2025. Iran, Iraq, Syria and Turkey possess 75% of the available water resources in the Middle East. Conflicts between countries because of the cross-boundary nature of river basins and shared aquifer systems are expected with increasing water shortages. In 2001, the share per individual of natural, fresh, renewable water resources in several Arab countries was less than 250 m3/year. During the period 1970–2001, the population of the Middle East countries increased from 173 to 386 million, which decreased the annual per capita freshwater share by 50%, reaching 1640 m3 (Al Mooji and Sadek 2005; and Majdalani 2005). About 15% of the world population receives over 50% of their water resources from neighboring countries, which will increase political conflicts because of water shortages. Syria and Iraq are negatively affected by the Turkish dams; some are already built and others are planned. These dams store the majority of water now reaching the Tigris and Euphrates Rivers. Iran and Iraq are competing over the Shat al Arab, i.e., concourse of the two major rivers. In North Africa, there is disagreement among Egypt, Sudan, Libya, Chad and Niger about rights to an 800-m thick regional Nubian Sandstone aquifer. Libya has utilized this basin in the Great Artificial River Project, which carries fresh groundwater from southern Libya to feed its northern coastal areas (Fig. 2.16). The World Bank (2007) noted that all the MENA countries are characterized by low rainfall (Fig. 2.17).

2.3  Water Resources in the Arab Countries The Arab region lies in an arid to semi-arid region, dominated from east to west by vast deserts, with a few periods of no rainfall. The coastal areas and nearby mountains are subjected to storms causing rains during certain seasons. The Arab countries on the Mediterranean coast receive rain during winter, while the Arab countries along the Arabian Sea in the Arabian Peninsula and southern Sudan receive summer rains associated with monsoon winds. These countries lack large internal rivers. The Nile is the most important river in Egypt and Sudan, and the Tigris and Euphrates are the most important rivers in Syria and Iraq. These rivers are international rivers, receiving most of their water from outside the Arab region. The Nile River originates in Central Africa, and its basin is shared by ten African countries, eight countries in the upstream parts of the basin (Burundi, Congo, Ethiopia, Kenya, Rwanda, South Sudan, Tanzania and Uganda), while Sudan and Egypt share the downstream portions. The Nile is the longest river in the world: its length reaches 6671 km between its upstream in Burundi in the south and the outlets in the Mediterranean Sea in the north. But, the actual Nile starts from Lake Victoria in Kenya, Uganda and Tanzania, and runs north across East Africa. Heavy rains cause the Nile flood during the summer, while the river reaches its lowest level between January and May.

2.3  Water Resources in the Arab Countries

37

Middle East and North Africa South Asia Western Europe East Asia and Pacific (including Japan and Koreas) North America Europe and Central Asia Australia and New Zealand Sub-Saharan Africa

a

Latin America and the Caribbean

0

10

20

30

40

50

60

70

80

percent Australia and New Zealand Latin America and the Caribbean North America Europe and Central Asia Sub-Saharan Africa East Asia and Pacific (including Japan and Koreas) Western Europe South Asia

b

Middle East and North Africa

0

5

10

15

20

25

30

35

40

1,000 meters /year 3

Fig. 2.16 (a) The total percentage of renewable water resources withdrawn in various regions (top), and (b) actual renewable freshwater resources per capita (1000 m3/year) by region (below). (After the World Bank 2007)

Syria, Iraq and Turkey share the Tigris and Euphrates river basins. But, Turkey controls the upstream reaches of both rivers and therefore control the volume of surface-runoff water moving through both rivers, especially the amount of water crossing the borders into Syria and Iraq. There are also some rivers in Syria, Lebanon and Jordan contributing to the surface water in the region. Water resources in the Arab region are subject to external pressure that arises from the fact that over 50% of freshwater resources originate from outside national borders (Arab Water Council 2012). This international water puts the Arab countries downstream at the mercy of upstream counties, such as Turkey in the case of the Tigris and Euphrates rivers, and Ethiopia in the case of the Nile. Ethiopia is

38

2  Overview on Global Water Resources

Qatar Bahrain United Arab Emirates

1

low precipitation, high variability

Kuwait

Normalized variability index

Mauritania Jordan Djibputi

high precipitation, high variability

0.8 0.6

Western Sahara 0.4 Saudi Arabia Morocoo Syria Mauritius Libya Iraq Tunisia Lebanon Jamaica Iran 0.2 Portugal Algeria Dominican Republic Australia Greece Egypt 0 0.2 0.4 Spam -1

-0.8

-0.6

-0.4

-0.2

-1

United States

0.4

Coted’lvire France India Ireland 0.2 Italy mexico United Kingdom

Turkey

Russian Federation Canada

low precipitation, high variability

0.6

0.8

1.0

Costa Rica Indonesia Papua New Guinea Malaysia

Brazil Zaire

0.6 0.8 Bermuda

high precipitation, high variability

-1

Normalized average precipitation

Fig. 2.17  The variability of rainfall in the MENA countries. (After the World Bank 2007)

constructing the Renaissance Dam on the Blue Nile, and Turkey is building large dams on the Tigris and Euphrates Rivers. These dam projects are expected to affect the available shares in Iraq, Syria and Egypt of these rivers’ water. Shared aquifer systems also exist among several Arab countries. The groundwater flow across borders in these aquifer systems far exceeds any river discharges (ESCWA/BGR 2012; UNESCWA/BGR 2013). However, no basin-level agreements exist between countries sharing aquifer systems (UN 2015). Internal pressure is related to the scarcity of water, where deserts cover 80% of the surface of the Arab region, in addition to the dominant dry climate, with temperature ranging between −17 °C in Lebanon Mountains and 46 °C in the Arabian Gulf countries. The mean annual rainfall varies between 25 mm in the Arabian Peninsula and North Africa and 1800 mm in southern Sudan (Fig. 2.18). About 2100–2300 Bm3 of rain falls annually on the Arab countries, and the mean annual evaporation is 2,250 mm. The area of the Arab countries is 15 Mkm2, while its renewable water resources do not exceed 7% of the world’s total water (Khouri 2003). Additional problems are related to deterioration of water quality and water pollution in many areas. The Arab countries receive an annual renewable, conventional water volume of 338 Bm3, of which 296.0 Bm3 surface water, 42.0 Bm3 groundwater recharge and 15,000 Bm3 is nonrenewable groundwater resources. The utilized water resources are 160.0 Bm3 each year (140.0 Bm3 surface water and 20.0 Bm3 groundwater), and

2.3  Water Resources in the Arab Countries

39

Fig. 2.18  Rainfall distribution in the Arab World. (After UNDP 2013)

the percentage of water use is 83% for agriculture, 12% for industry and 5% for domestic purposes. The nonconventional water resources are 8  Bm3 of treated-sewage water and 2.0 B of desalinated water, produced mainly by desalination plants in the Arabian Gulf countries (UNDP 2013). There are 34 permanent rivers in the Arab region, with basins spanning widely different areas (98 km2 of the El-Zahrani River in Lebanon and 2.80 Mkm2 of the Nile basin), lengths (River Al Sin in Iraq 6-km long and the Nile River 6671 km), and annual discharges (discharge of River Miliana in Algeria is 50 Mm3, and discharge of River Nile is 84 Bm3). In addition, the Arab region incurs hundreds of thousands of seasonal floods which carry tens of billions of m3 of water every year. The renewable groundwater resources are estimated at 42 Bm3/year, while the nonrenewable resources, stored in 12 major aquifer systems in the Arabian Peninsula and North Africa, are between 13,000 and 15,000 Bm3 of old groundwater. Two of the three basins that hold the most important groundwater resources include: the Eastern Erg basin located south of the Atlas Mountains in Algeria with groundwater storage of 1400 Bm3 and the Nubian basin in Egypt, Libya and Sudan which stores 7000  Bm3, providing the Egyptian Oasis Al Kharga, Al Dakhla and Farafra with water. The man-made project the Great River in Libya transfers 700 Mm3 of groundwater from the Nubian Sandstone aquifer in the south to Libya’s coastal cities in the north. The third basin is Disi basin between Jordan and Saudi Arabia. There are also less important basins producing 15.3 Bm3 of water totally utilized (ACSAD 2003).

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2  Overview on Global Water Resources

The large reserves of seawater resources are used in water desalination, which is widely practiced the Arabian Gulf countries. According to ACSAD (2003), the treated-sewage water is the second most important nonconventional water source in several Arab countries. This water is expected to play a greater role in the future. The volume of treated-sewage water currently used is 6 Bm3 and is predicted to eventually reach double this. The population of the Arab region in 2010 was 220 million, and the per capita water share was 1650 m3/year, compared with a 13,000 m3/year/capita water share globally. Despite the fact that 2000–2285 Bm3 of rain falls on the Arab countries every year, a major part of this water is lost through evaporation or as surface runoff into the sea. The main water users in the Arab region are agriculture (87%), industry (7%) and domestic (6%) sectors (Al Bayyati 2002; Table 2.13). There is a marked decrease in per capita water share in the Arab countries (Fig. 2.19). The per capita water share in 1950 was 3800 m3, decreased to 1027 m3 in 1996, and is less than 1000 m3 at present. In 2035, the per capita water share is predicted to reach 464 m3. The African per capita water share is 5500 m3/year, and the Asian annual per capita water share is 3500 m3. There is a general understanding of the limited renewable water resources in the Arab region; this spans many aspects, including: the decrease of per capita water share; shortage of financial resources allocated for development of water resources; lack of public awareness of the seriousness of water-shortage problem; absence of agreement securing the right in the water coming from outside their borders; absence of integrated water management that takes into account the ecological, social and economic dimensions; and failure to utilize international experience in this field. There is no agreement on water strategy, and there is no clear vision in the Arab region concerning national and regional levels and future steps regarding water issues. The total quantity of water exploited in the Arab region in the year 2000 was about 187 Bm3, representing 68% of available water resources estimated at 274 m3. Some countries suffer from water shortage due to excessive pumping of old groundwater (the World Bank 2009). Saudi Arabia ranks first in this regard, where the annual water deficit is 3390 Mm3. The water deficit in the UAE is 425 Mm3, and in Bahrain it is 66 Mm3. In contrast, some Arab countries such as Iraq (21,106 Mm3) have excess water resources. Agriculture consumes 88% of water resources; industry consumes 5% and domestic consumption is 7%. The total area of the Arab region is 1400 million hectares, of which 197 million hectares are cultivable, representing 14% of the total area of the Arab region (Saab 2015). The area of cultivable land can increase through land reclamation projects to reach 236 million hectares, representing 17% of the total area of the Arab region. The actual cultivated area in the Arab countries represents 35% of cultivable land. Saab (2015) noted that the Arab countries use nonconventional, in addition to conventional water resources, to meet escalating demands. While Syria, Morocco

4.1 10.3 3.0 3.0 6.6 12.4 32.0 37.4 33.9 8.6 4.3 4.9 6.2 5.3 6.7

800 1012 24.2 1280 81 55 95 201 415 408 2700 453 101 144 12,451

27,000 22,722 11,460 63,906 1978 491 174 574 9054 1367 64,102 30,351 7369 5065 273,724

After Al Bayyati (2002)

Country Jordan UAE Bahrain Tunis Algeria Djibouti Saudi Arabia Sudan Syria Somalia Iraq Oman Palestine Qatar Kuwait Libya Lebanon Egypt Morocco Mauritania Yemen Total

Water resources used for domestic purposes Quantity Percentage 216 24.1 246 20.1 107 39.3 313 10.8 2181 40.4 20 16.4 1508 9.2

Total of available water resources (Mm3) 1022 798 206 3915 15,475 250 6445 200 300 0 2140 5 43 17 13 60 7.4 5900 322 29.3 72 10,189

1.0 3.1 0.0 5.0 0.4 9.8 5.7 2.4 4.9 1.5 9.3 2.9 1.8 2.7 5.4

Water resources used for industrial purposes Quantity Percentage 24.6 2.8 27 2.2 19 7.0 69 2.4 680 12.6 2 1.6 192 1.2

Table 2.13  Invested water resources in different water sectors in the Arab World in 2000

18,410 8500 785.7 39,380 1150 343 185.4 324 750 4275 54,500 10,180 1500 2500 164,295

94.9 86.6 97.0 92.0 93.0 77.8 62.3 60.2 61.2 89.9 86.4 92.2 92.0 92.0 87.9

Water resources used for agricultural purposes Quantity Percentage 655 73.1 950 77.7 146 53.7 2518 86.8 2543 47.0 100 82.0 14,600 89.6 19,410 9812 810 42,800 1236 441 298 538 1225 4757 63,100 11,045 1630 2716 186,935

Total water use (Mm3) 896 1223 272 2900 5404 122 16,300 7591 12,910 65 1106 742 50 −124 36 7829 −3390 1002 9306 5739 2349 86,790

Water surplus or deficit (Mm3) 126 −425 −66 1015 10,071 128 −9855

2.3  Water Resources in the Arab Countries 41

42

2  Overview on Global Water Resources

Fig. 2.19  Total renewable water resources per capita, by country. (After the World Bank 2009)

and Jordan depend mainly on groundwater, Sudan, Iraq and Egypt depend primarily on surface water. The percentage of nonconventional water resources in annual water budgets is steadily increasing.

2.3.1  Conventional Water Resources 2.3.1.1  Surface-Water Resources The Arab region has permanent rivers, seasonal water courses and dry wadis. International water crossing the borders in some Arab countries is carried by large rivers, such as the Nile, Tigris, Euphrates and Senegal (with their upstream segments outside their borders). Some other river basins are shared among Jordan, Lebanon and Syria (Table 2.14). In 2008, the water capacity of dams in Arab countries was about 356  km3; the dams are mainly located in Morocco (16.90  km3), Syria (19.70 km3), Iraq (151.80 km3) and Egypt (168.20 km3). The advantages and disadvantages of the High Dam of Aswan in Egypt were summarized by the UNDP (2013).

2.3  Water Resources in the Arab Countries

43

Table 2.14  River basins, basin size (km2), river length (km) and average discharge (m3/year) of main river basins in Arab countries No. 1 2 3 4 5 6 7 Total

Basin name Nile Euphrates Tigris Jordan River Al Assi Al Kabir Senegal

Basin size (km2) 3173 647,075 146,239 19,839 37,000 0.991 300 851

River length (km) 6693 2330 1718 251 448 90 1800 6637

Average discharge (m3/year) 109,500 32,000 52,000 1340 2800 300 22,000 110,440

After UNDP (2013)

Table 2.15  Major aquifer systems in the Arab countries No. 1 2 3 4 5 6 7 8

Aquifer system Nubian sandstone Continental intercalary Terminal complex Bechar Fazzan Eastern Mediterranean limestone Hauran and Arab mountain basalt Eastern Arabia Tertiary Carbonate

Nature of the aquifer system Sandstone aquifer Sandstone aquifer Sandstone aquifer Sandstone aquifer Sandstone aquifer Limestone aquifer Gravel aquifer Limestone and dolomite aquifer

Area (1000 km2) 2200 600 430 240 450 48 15 1600

Modified from UNDP (2013)

2.3.1.2  Groundwater Resources Groundwater is the second major conventional water resource in the Arab countries. Aquifer systems, within national boundaries or shared between two or more countries, are recharged through direct precipitation, rivers or seasonal streams or lateral movement of groundwater flow from recharge areas (Table 2.15). According to the UNDP (2013), extraction of groundwater in several countries represents more than 50% of the water used, and even reaches 84% of the total in Saudi Arabia.

2.3.2  Nonconventional Water Resources Several Arab countries are heavily dependent on desalinated water and treated wastewater, in addition to cloud seeding, rainwater harvesting and reuse of irrigation drainage flows.

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2  Overview on Global Water Resources

2.3.2.1  Desalinated Water The World Bank (2009) and UNDP (2013) expect that water desalination in Arab countries will expand in the future and most of the development will take place in the GCC countries (Fig. 2.20; Table 2.16). Electricity and desalination cogeneration have lowered the price of desalinated water produced by thermal desalination methods (Figs. 2.21 and 2.22). 2.3.2.2  Treated Wastewater The UNDP (2013) noticed that several Arab countries are now expanding the use of treated wastewater for additional purposes. Integrated water-resources management, urban development, industrialization and a growing agricultural sector are main motivation for reusing treated wastewater. Despite the ambitious plans of expanding wastewater reuse, several countries lack institutional regulations and guidelines for treated wastewater. In addition, the data on production, treatment and reuse of wastewater in the Arab region are not enough for comparison and analysis across countries (Fig. 2.23; Table 2.17). 2.3.2.3  Other Non-conventional Water Sources In addition to desalinated water and treated wastewater, several Arab countries have investigated additional water-supply sources. Examples of these nonconventional water harvesting and conservation techniques include: micro-catchments, cisterns,

Fig. 2.20  Present and contracted desalinated-water capacity in some Arab countries. (After UNDP 2013)

2.3  Water Resources in the Arab Countries

45

Table 2.16  Desalinization capacities in some Arab countries (in 1000 m3/day)

Country Algeria Egypt Libya Morocco Tunisia Jordan Saudi Arabia Kuwait Bahrain Qatar Oman UAE Total (1000 m3/day)

Desalination capacity (1000 m3/day) 727.0 3191 432 528 899 1869 440 1000 59 285 89 195 240 541 7410 12,564 2081 3446 519 1183 1197 1676 377.0 1140 5730 9030 20,200 36,648

Desalination capacity (forecast (1000 m3/day) 4985 8214 888 1536 3775 7206 1790 3212 491 862 297 481 898 1541 17,654 26,816 4617 6725 1977 3406 2481 3930 2059 3713 12,330 18,270 54,242 85,911

After the World Bank (2009)

Fig. 2.21  Decrease in the cost of MSF plants during the period 1955–2003. (After UNDP 2013)

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2  Overview on Global Water Resources

Fig. 2.22  Comparison of the RO, MSF and MED costs of operation. (After UNDP 2013)

Fig. 2.23  Treated wastewater produced in various Arab countries during 2009–2010. (After UNDP 2013)

2.3  Water Resources in the Arab Countries

47

Table 2.17  Total treated-wastewater production in some Arab countries Total water withdrawal (Bm3/ year) Country Yemen 3.40 Tunisia 2.85 Palestine 0.418 Sudan 37.32 Somalia 1.298 Syria 16.70 Qatar 0.55 Oman 1.321 Mauritania 1.70 Morocco 12.60 Lebanon 1.31 Kuwait 0.913 Jordan 0.941 Libya 4.326 Iraq 66.00 UAE 3.998 Egypt 68.30 Djibouti 0.019 Comoros 0.3574 Bahrain 0.3574 23.67 Saudi Arabia Algeria 6.07 Total 256.303

Total wastewater produced (Bm3/ year) 0.074 0.461 0.05 – – 1.37 0.444 0.098 – 0.700 0.31 0.25 0.117 0.546 0.575 0.50 3.76 – – 0.0449 0.73

Volume of treated wastewater (Bm3/ year) 0.046 0.240 0.03 – 0.00 0.550 0.066 0.037 0.0007 0.177 0.004 0.239 0.111 0.04 0.098 0.454 2.971 0.00 – 0.076 0.652

Volume of treated wastewater reused (Bm3/year) 0.006 0.068 0.00544 – – 0.550 0.043 0.023 0.00035 0.080 0.002 0.078 0.102 0.04 0.0055 0.248 0.700 – – 0.0163 0.166

0.82 10.85

0.70 6.492

0.051 2.164

After the World Bank (2011)

underground storage and small dams. Spreading systems include terraces, irrigation-­ diversion dams, sloped catchment areas and artificial recharge dams (UNDP 2013; Table 2.18).

2.3.3  Water Demand The shortage of water resources and difficulty of the climate limit the efforts of Arab countries to increase the areas of cultivated land, which vary from one country to another. In Lebanon and Syria, the area of cultivated lands is 30%, while it does not exceed 3% in Sudan, Egypt and Algeria (Table 2.19). The annual water consumption of their total available water resources constitute 62% (164 Bm3). The current area of irrigated land can be doubled through the use of modern irrigation technologies, such as sprinkler and drip irrigation. The annual

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Table 2.18  Total rainfall and percentage utilization through water harvesting in various Arab countries Country Jordan Tunisia Sudan Syria Morocco Yemen Libya Algeria Mauritania Egypt

Volume (Bm3) Rainfall 8.5 36 400 85 150 68 30 192 175 15

Utilization 0.425 0.936 4.0 2.0 20.0 6.12 0.90 5.76 4.37 0.225

Utilization of Rainfall (%) 5.0 2.6 1.6 2.4 1.3 9.0 3.0 3.0 2.5 1.5

After AOAD (2002) Table 2.19  Water demand in the Arab countries by sector in 2011 as percentage of freshwater withdrawals Country Yemen UAE Tunisia Syria Sudan Somalia Saudi Arabia Qatar Palestine Oman Morocco Mauritania Libya Lebanon Kuwait Jordan Iraq Egypt Djibouti Comoros Bahrain Algeria Average After UNDP (2013)

Industry 1.82 1.73 3.68 3.67 0.60 0.06 3.00 1.80 6.94 1.44 2.86 1.58 3.05 11.45 2.28 4.08 14.70 5.86 0.00 5.00 5.68 13.54 4.31

Domestic 7.43 15.43 12.81 8.80 2.28 0.45 9.00 39.19 47.85 10.14 9.81 4.74 14.10 29.01 43.86 30.96 6.52 7.76 84.21 48.00 49.78 22.15 22.92

Agriculture 90.74 82.84 75.96 87.53 97.12 99.48 88.00 59.01 45.22 88.42 87.31 93.69 82.85 59.45 53.87 64.96 78,79 86.38 15.79 47.00 44.54 63.95 72.10

Total (Bm3) 3.57 4.00 2.85 16.76 37.14 3.30 23.67 0.44 0.42 1.32 12.61 1.60 4.33 1.31 0.91 0.94 66.00 68.30 0.02 0.01 0.36 6.16 11.64

2.3  Water Resources in the Arab Countries

49

Table 2.20  Water losses from water distribution networks in various Arab countries Country Bahrain Egypt Iraq Jordan Kuwait

Water loss (%) 15 50 50 50 10

Country Lebanon Oman Saudi Arabia Syria Yemen

Water loss (%) 50 23 40 48 30

After UNDP (2013)

volume of water devoted to domestic purposes in the Arab region is 12,450 Mm3, representing 7% of total water consumption. The per capita share in water devoted to domestic purposes varies from less than 3 m3 in Somalia to more than 1000 m3 in the UAE. No safe drinking water is available for more than 80 million people living in the region, which represents one-third of the population in the Arab region. The percentage varies by country and, even in the same country, between urban and rural areas. For example, 70% of people in Somalia do not have access to safe drinking water, while almost all residents of the GCC countries have access to safe drinking. Water-distribution networks in the Arab region are suffering from water loss of 40–60% of the transported water (Table  2.20). This is related to the aged water-­ distribution networks, leading to leakage of a great amount of potable water into the ground. The water devoted to the agricultural sector reached 10 Bm3, representing 5% of the total water use. This percentage varies between 13% in Algeria and 0% in Somalia, while the average varies between 55% in Europe and 23% globally, a fact explaining the retardation of the agricultural sector.

2.3.4  Water Challenges The main challenges facing water resources in the Arab countries, as noted by Al Zubari (2013 and 2014), are population growth, migration to cities, urban development, industrialization and increases in water production and consumption. These challenges decreased the per capita water share between 1992 and 2011 (Fig. 2.24). Global climate change is expected to complicate the water-shortage problem (Nikulin 2013; UNESCWAa 2013; UNESCWA/BGR 2013; Donat et al. 2014). OHCHR (2010) and UN (2015) urged the Arab countries to realize the need for sustainable development of water resources on national and regional levels. The use of treated wastewater for irrigation is expanding in Jordan, and treated wastewater is injected between freshwater in coastal aquifers and saline seawater (Zekri et al. 2014).

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2  Overview on Global Water Resources

Fig. 2.24  The per capita in renewable water in the Arab World. (After UNDP 2013)

2.3.4.1  Overexploitation of Groundwater Resources Groundwater exploitation in the Arab countries is intended to meet the rising demand for irrigation and domestic purposes. Overpumping of aquifer systems beyond their safe-yield levels has resulted in decline of groundwater levels (Fig. 2.25), increasing groundwater salinity and deterioration of groundwater quality due to seawater intrusion (Rizk and Alsharhan 2008). 2.3.4.2  Sustainable Management of Groundwater Resources The aquifer systems in the Arab countries have to be managed in a sustainable manner, taking into consideration each aquifer’s safe yield, which is defined by as pumping water from an aquifer system at a rate equal or less its recharge rate (Todd 1980). This mode of development ensures sustainability of aquifer systems and their continuous contribution as reliable sources of water. 2.3.4.3  Natural Variability of Water Resources Natural water resources are vulnerable to climate variation and random exploitation patterns (UNDP 2013; UN 2015). Rainfall variability in the Arab region, which is related to the season, location and rainfall cyclicity, decreased from 1988–1992 to 1998–2002 (Fig. 2.26).

2.3  Water Resources in the Arab Countries

51

Fig. 2.25  Observed depletion in the groundwater level of the Saïss basin in Morocco during the period 1963–2007. (After UNDP 2013)

Fig. 2.26  Rainfall Index for various Arab countries. (After UNDP 2013)

2.3.4.4  Shared Water Resources The UN (2015) described shared surface water and groundwater resources in the Arab countries in the Arabian Peninsula and North Africa. Managing these shared water resources requires close cooperation and coordinated efforts between countries involved, either Arabs or Arabs and non-Arabs, to maximize water resources, reduce losses and ensure fair sharing of water resources for both upstream and downstream countries.

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2  Overview on Global Water Resources

2.3.4.5  Water Pollution Water resources, surface water and groundwater are subject to pollution from domestic, agricultural and industrial activities. Pollution deteriorates water quality and makes it unfit for various uses (WHO 1984). The UN (2015) summarized the challenge represented by water pollution in the Arab region.

2.4  Water Resources in the Arabian Gulf Region The share of the GCC countries of the total water resources in the Arab region is 4.6%, which is the lowest compared with other areas such as Iraq, Syria, Jordan and Palestine (40.9%), the North African countries (23%) and the countries in the Nile basin (30%). The total water resources in the Arabian Gulf countries between 1988 and 1997 reached 10.31 Bm3, including 8.00 Bm3 of conventional and 2.31 Bm3 of nonconventional resources. Water demand in the GCC countries has increased from 1.0  Bm3 in 1980 to 22.50 Bm3 in 1990. In the year 1995, water needs reached 29.70 Bm3, and by the year 2025 water needs are estimated to reach 32.23 Bm3. Despite conflicting numbers and predictions, the fact remains that there will be water crises in the future arising from the growing gap between available water resources and actual water demands (Al Senafy et al. 2003). Predictions of total water demand for various purposes in the GCC will reach about 32.23 Bm3 by 2025, meaning that demand will rise by around 18.74 Bm3 of the 1995 water requirements, which was estimated as about 13.49 Bm3. Estimation of available water resources in the year 2025—represented by artificial groundwater recharge of 7.20 Bm3/year, expansion in desalination industry to provide 3.0 Bm3 and reuse of treated sewage water of 3.0 Bm3, and assuming that all surface water will be harvested and utilized, which amounts 8.30 Bm3—will not exceed 21.50  Bm3. In comparison with the predicted water demand in 2025, it becomes clear that the available water resources will not be enough to meet projected water demands, and there will be a water deficit of 10.73 Bm3 in 2025 (Al Zubari 2003; Table 2.21). Among the features of the predicted water shortage in the GCC countries is the decrease in per capita water share in available water resources during the next two decades. The per capita water share of 1000–1700  m3/year indicates a water-­ shortage problem. The drop of the per capita water share per year below 1000 m3 indicates a critical water shortage and below 500 m3 reflects water scarcity. The World Bank (2005) expects that the per capita water share in the GCC countries will decrease (Fig. 2.27). The share of the individual in available, natural water resources in the GCC countries is less than 250 m3/year, while water consumption per capita in the region is 1035 m3/year, indicating the wide gap between the available resources and the actual needs (Table 2.22).

2.4  Water Resources in the Arabian Gulf Region

53

Table 2.21  Annual water resources in the GCC countries in Mm3 Groundwater Mm3 Percent 160 71.4 144 57.6 80 19.8 645 93.8 14,430 93.6 900 69 16,359 89.3

Country Bahrain Qatar Kuwait Oman Saudi Arabia UAE Total

Desalinated water Mm3 Percent 56 25 83 33.2 240 59.6 32 4.7 795 5.1 342 26.2 1548 8.5

Treated-sewage water Mm3 Percent 8 3.6 23 9.2 83 20.6 10.5 1.5 217 1.4 62 4.8 403.5 2.2

Total Mm3 224 250 403 687 15,442 1304 18,310

After Al Zubari (2003)

Water availability (m3 per capital)

1400 1200

Bahrain Kuwait Oman

1000

Qatar

800

Saudi Arabia United Arab Emirates GCC

1400

Absolute water poverty

400 200 0

1970

1980

1990

2000

2010

Fig. 2.27  Per capita availability trends in the GCC countries for the period 1970–2010. (After the World Bank 2005)

Table 2.22  Per capita water share and water consumption in the GCC countries in Mm3/year

Country Bahrain Kuwait Oman Qatar Saudi Arabia UAE Total

Available water resources Mm3/year 243 616 2486 340 7092

Consumed water Mm3/year 287 633 1241 439 21,155

Per capita share Mm3/year 437 364 1126 620 388

Per capita consumption Mm3/year 515 374 562 801 1159

1087 11,864

2212 25,967

492 466

1001 1020

After the World Bank (2005)

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2  Overview on Global Water Resources

2.4.1  Conventional Water Resources The conventional water sources in the GCC region include rain, floods and groundwater. The amounts of rains falling on individual GCC countries are: 127.0 Bm3 in Saudi Arabia, 14 Bm3 in Oman, 4.20 Bm3 in UAE, 2.20 Bm3 in Kuwait, 1.89 Bm3 in Qatar and 0.006 Bm3 in Bahrain (the World Bank 2005). The high evaporation rate lowers the contribution of rainfall to conventional water resources. 2.4.1.1  Surface Water The GCC countries lack conventional surface water resources such as permanent rivers or lakes because of the prevailing arid climate. The mean annual rainfall ranges from 75 to 140 mm, with great irregularity in time and space, while the daily average evaporation varies between 2.5 mm in winter and 17 mm in summer. The groundwater storage in shared aquifer systems in the GCC countries was estimated at 4840 Bm3 in 1998. These aquifers are classified into shallow unconfined aquifers and deep confined aquifers. The shallow aquifers occur along main wadi channels and under flood plains and receive an annual recharge of 4.50 Bm3. The groundwater stored in these aquifers is renewable and is estimated at 131 Bm3. The groundwater stored in deep confined aquifers is nonrenewable fossil water. Confined aquifers are the most dominant in Saudi Arabia, which shares some of these aquifers with the other GCC countries. This water has been stored in the ground beginning thousands of years ago, and the reserves are 2175  Bm3, the largest part of it (1919 Bm3) occurring in Saudi Arabia. The recharge to groundwater in these aquifers is rather limited and not exceeding 2.70 Bm3/year. 2.4.1.2  Groundwater The World Bank (2005) noted that groundwater in renewable and nonrenewable aquifer systems still represents the largest supply of water, and the aquifer systems still represent the main source of water for agriculture and domestic purposes in Oman. The recharge for these aquifers occurred millions of years ago during the Pleistocene pluvial periods, but the present-day recharge of these aquifers is virtually nil or totally absent. Groundwater exploitation from these aquifers has to be carefully calculated in order to avoid their fast depletion. Given the wide variability of the hydraulic properties of these aquifers, the amount of their stored water is difficult to estimate. Although several modeling studies have been carried out on these aquifers, additional work is needed, as soon as new drilling and testing data on these aquifers become available. The brackish and saline water reserves of these aquifers are large but are unknown. The depth to groundwater in some of these aquifers may exceed 500 m (Table 2.23). The quantities of water which can be safely pumped from these aquifers is difficult to quantify, and there is a major concern regarding their sustainable development.

2.4  Water Resources in the Arabian Gulf Region

55

Table 2.23  Most important aquifers in the GCC countries Aquifer Neogene Dammam Umm er Radhuma Wasia Minjur Tabuk Saq Wajid

Thickness (m) 30–100 200 500 200–230 350 1000 500–600 300–400

TDS (mg/L) 100–4000 1000–6000 300–1000 1000–3000 400–1600 500–3500 500–1500 500–1000

Depth to groundwater (m) 10–150 100–600 250–600 230–1200 1400 10–1400 100–1500 15–1110

After the World Bank (2005)

Paleozoic and Mesozoic aquifers systems are mainly confined to Saudi Arabia, except for the Dammam aquifer which extends further east into other GCC countries, where it represents the main groundwater source in Bahrain, Qatar and Kuwait. The Dammam aquifer in these countries is receiving continuous recharge by rains falling on the aquifer outcrops in Saudi Arabia (White 2010). Aquifer systems such as the Dammam aquifer system has to be managed in cooperation between all countries utilizing the aquifer to ensure its sustainable development in the future. Rainfall on the mountain ranges in Oman and eastern UAE represents the main source of recharge of alluvial aquifer systems surrounding these mountains, from the east and west. The groundwater resources in the GCC countries were summarized in the World Bank report (2005).

2.4.2  Nonconventional Water Resources Since the early 1950s, some GCC countries started depending on water desalination and treatment of wastewater, as nonconventional water resources, to bridge the growing gap between the limited, available water resources and the growing demand for water by all sectors. The share of both water sources reached 2142 Bm3 in 1998. 2.4.2.1  Desalinated Water Lattemann and Hopner (2003), UNEP-MAP/MED POL (2003), the World Bank (2005), the World Bank and AGFUND (2005), Abderrahman and Hussain (2006), Bates et al. (2008), Al-Jamal and Schiffler (2009), Al-Hussayen (2009), Darwish et al. (2009), GWI (2010), Khatib (2010), Dawoud and Al Mulla (2012) and Markaz (2012) addressed water desalination in the GCC countries. The population growth, fast social and economic development and climate change are expected to increase the water-scarcity problem. For these reasons, more than 50% of world’s desalination capacity is installed in the Gulf region, and this percentage is expected to increase in the future.

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Desalinated water is produced by removing salts from seawater or brackish groundwater for use in drinking and domestic uses. Desalination technology was introduced in the Arabian Gulf region in the mid-1950s. Since then, the contribution to domestic needs has increased with decreasing groundwater quantity and quality. Desalinated water is the second main source of water in the GCC countries after groundwater and represents 21% of available water resources, as production increased through the 1990s. The GCC countries spent about US$40 billion on the construction of desalination plants and water distribution lines, and they will spend an equal amount of money during the next 30 years on construction of additional desalination plants to meet the ever-increasing population and development in the industrial sector. As a result of water shortage, the demand on desalination water is expected to increase by an annual rate of 9% during the next three decades. The production of desalination plants in the world reached 24 Mm3 of drinking water in 2000. Saudi Arabia ranks first in the production of desalinated water in the world, and the UAE ranked second. Statistics indicate that the number of large desalination plants in the GCC countries is 62, half of these plants are in Saudi Arabia. These plants include the largest desalination plant in the world (the Al Jubail plant in Saudi Arabia), which produces 900,000 m3 per day. Altogether, the GCC countries obtain 18% of their water demands from desalination plants, with the production of 8.30 Mm3 of water per day, which represents 60% of the global production of desalinated water. The dependence of the GCC countries on desalinated water varies; the percentage of water needs met by desalination plants are: 64.5% in the UAE, 63.2% in Kuwait, 49.5% in Qatar, 19% in Bahrain, 11% in Saudi Arabia and 10.2% in Oman. 2.4.2.2  Wastewater Treatment and Reuse Treated-sewage water is basically used for irrigating gardens and public parks, as well as for landscaping. Treatment of sewage water and agricultural drainage water is conducted in three steps: physical treatment, biological treatment and chemical treatment. Almost all the GCC countries are achieving the tertiary treatment. Experts believe that secondary treated-sewage water can be used for agriculture and some industrial uses. The increasing water use in urban areas, the construction of sewage-treatment plants and the expansion of sewage networks has increased the volume of treated-­ sewage water since the 1990s. The present total capacity of the sewage-treatment plants in the GCC countries is 1120  Mm3/year, which represents about 30% of domestic use. Treated-sewage water represents 4% of water used in the GCC countries.

2.4  Water Resources in the Arabian Gulf Region

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Saudi Arabia used 36.80  Mm3 in 1996, UAE used 108  Mm3, Oman used 26.0  Mm3, Qatar used 35.40  Mm3, Kuwait used 24.0  Mm3 and Bahrain used 12.0 Mm3 during the same year. The volume of treated-sewage water in 2010 in the GCC countries has reached 3.1 Bm3, but the total volume of this water is not actually used. The volume of treated sewage actually used in the GCC countries in 1998 was about 333 Mm3, in 1995 was 392 Mm3, and in 2000, the volume of treated-sewage water production was 917 Mm3 (the World Bank 2005). There are several aspects which can be improved to enable the GCC countries to better use their water resources in the most efficient manner, such as through water conservation, reduction of water losses, artificial rain, rainwater harvesting and expansion in construction of groundwater-recharge dams, which divert a good part of floodwater to recharge aquifers. Additional features include artificial recharge, expansion in the application of advanced irrigation technologies, protected agriculture and biosaline agriculture. To improve the current water-resources management and decision-making process, state-of-the-art techniques in water-resources investigations, such as remote sensing, geographic information systems (GIS), modeling techniques and isotope hydrology, are powerful and valuable tools.

2.4.3  Water Demand Table 2.24 illustrates increasing water demand by all sectors in the GCC countries, with agricultural water demand in the forefront. The problem of water scarcity is further complicated by climate change (UNESCO 2015). Table 2.24  Water consumption by sector in the GCC countries (in Mm3) in 2010 Water consumption by sector (Mm3) Population (million) Municipal Industrial Agricultural Country Mm3 % Mm3 % 2005 2010 2025 2050 Mm3 % UAE 4.11 8.19 9.9 12.2 983 21.4 477 10.4 3140 68.2 Saudi Arabia 22.67 28.69 36.0 44.6 2283 13.1 753 4.3 14,410 82.6 Qatar 0.80 1.68 2.1 2.4 370 56.7 22 3.4 261 39.9 Oman 2.51 3.42 3.9 5.3 182 10.0 94 5.2 1546 84.8 Kuwait 2.99 3.48 3.7 5.2 646 54.8 20 1.7 513 43.5 Bahrain 0.73 1.05 1.7 2.0 231 51.3 29 6.4 190 42.3 Total 33.8 46.5 57.3 71.7 4695 18.0 1395 5.3 20,060 76.7 Compiled from Markaz Research (2012), UNESCO (2015)

Total Mm3 4600 17,446 653 1822 1179 450 26,150

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2.4.4  Water Challenges 2.4.4.1  Reduction of Water Losses The GCC countries realized the financial costs associated with significant losses from the municipal water-distribution networks (the World Bank 2005). Water losses in Bahrain were estimated at 30% and fluctuated between 20% and 40% in Saudi Arabia. The situation combines with urban water logging, as well as other problems associated with significant financial losses. The GCC countries have lowered water losses to about 10–15%, the percentage considered acceptable according to the international standards. 2.4.4.2  Industrial Water and Wastewater Management According to the World Bank (2005), the total water consumption in the industrial sector in the GCC countries increased from about 1.3% of the total (321 Mm3) in the mid-1990s to more than 5.3% of the total water consumption (1.3 Bm3) in 2012. The groundwater almost satisfies the needs of the industrial sector (96%), with a small contribution by desalinated water (4%).

References Abderrahman W, Hussain T (2006) Pollution impacts of desalination on ecosystems in the Arabian Peninsula. In: Amer KM et al (eds) Policy perspectives for ecosystem and water management in the Arabian peninsula. UNESCO/UNU-INWEH, Paris/Hamilton ACSAD (2003) Management, protection and sustainable use of groundwater and soil resources in the Arab region: guideline for the delineation of groundwater protection zones. Technical cooperation report, vol 5, ACSAD-BGR, p 310 Al Bayyati AH (2002) Water and struggle for existence in the Arab world, Zayed Center for Coordination and Follow-up, UAE, p 119 Al Mooji Y, Sadek T (2005) State of water resources in the ESCWA region. Proceedings of the Seventh Gulf Water Conference on Water in the GCC – towards an integrated management, Kuwait, vol 1, pp 143–164 Al Senafy MF, Al Fahad K, Hadi K (2003) Water management strategies in the Arabian gulf countries. In: Alsharhan AS, Wood WW (eds) Water resources perspective. Evaluation, management and policy, Development in Water Science 50. Elsevier, Amsterdam, pp 221–224 Al Zubari WK (2003) Alternative water policies for the Gulf Cooperation Council countries. In: Alsharhan AS, Wood WW (eds) Water resources perspective. Evaluation, management and policy, Development in Water Science 50. Elsevier, Amsterdam, pp 155–167 Al Zubari WK (2013) Water, energy, and food nexus in the Arab region. In: Annual Conference of the Arab Forum for Environment and Development ‘Sustainable Energy: Prospects, Challenges, Opportunities’. Arab Forum for Environment and Development (SFED), Sharjah Al Zubari WK (2014) Sustainable water resources management in the GCC countries. Water Resources Management Program, College of Graduate Studies, Arabian Gulf University, Bahrain. (Unpublished)

References

59

Al-Hussayen A (2009) Inaugural speech by the Minister of Water and Electricity, Saudi Arabia, Jeddah, Saudi Water and Power Forum Al-Jamal K, Schiffler M (2009) Desalination opportunities and challenges in the Middle East and North Africa region. In: Jagannathan NV et  al (eds) Water in the Arab world: management perspectives and innovations. World Bank, Washington, DC, pp 479–494 AOAD (Arab Organization for Agricultural Development) (2002) Enhancing water harvesting technology in the Arab region, Khartoum, Sudan (in Arabic) Arab Water Council (2012) Arab strategy for water security in the Arab region to meet the challenges and future needs for sustainable development 2010–2030. Arab Water Council, Cairo Bates B, Kundzewicz ZW, Wu S, Palutikof J (eds) (2008) Climate change and water: IPCC Technical Paper VI. IPCC Secretariat, WMO/UNEP, Geneva, p 200 CEDARE (Centre for Environment and Development for the Arab Region and Europe) (2006) Water conflicts and conflict management mechanisms in the middle east and north Africa region, p 49 Dai A (2012) Connecting earth’s water cycle to climate: NCAR’s (University Corporation for Atmospheric Research) climate and global dynamics division, UCAR, AtomsNews Darwish MA, Al-Najem NM, Lior N (2009) Towards sustainable seawater desalting in the Gulf area. Desalination 235(1–3):58–87 Dawoud AM, Al Mulla MM (2012) Environmental impacts of seawater desalination: Arabian Gulf case study. Int J Environ Sustain 1(3):22–37 Dedercq R, Condom N (2015) Alera Project. Water reuse for sustainable development, Launch Conference, Ecofilae, Environment Donat MG, Sillmann J, Wild S, Alexander LV, Lippmann T, Zwiers FW (2014) Consistency of temperature and precipitation extremes across various global gridded in situ and reanalysis data sets. J Clim 27:5019–5035 Escobar IC, Schäfer AI (2010) Sustainability science and engineering v. 2. In: Sustainable water for the future. Water recycling versus desalination. Elsevier, Amsterdam, p 399 ESCWA (2005) Development of frameworks to implement national strategies of integrated water resources management in the ESCWA countries. United Nations, New York, p 94. (in Arabic) ESCWA (2007) State of water resources in the ESCWA region, Water Development Report 2. United Nations, New York, p 60 ESCWA (Economic and Social Commission for Western Asia) (2001) Water desalination technologies in the ESCWA member countries. United Nations, New York, p 159 ESCWA/BGR (2012) Inventory of shared water resources in western Asia: finding on status, challenges and cooperation, Inventory roundtable: transboundary water resources management in the southern Mediterranean, Rome, Italy, p 22 FAO (Food and Agriculture Organization of the United Nations) (2010) AQUASTAT database. Available at http://www.fao.org/nr/water/aquastat/main/index.stm. Accessed on 13 Apr 2014 GWI (Global Water Intelligence) (2009) Municipal water reuse markets 2010. Media Analytics Ltd, Oxford GWI (Global Water Intelligence) (2010) Desalination markets 2010: global forecast and analysis. GWI, Oxford IDA (International Desalination Association) (2013) Desalination market outlooks, monthly archives, February 2013 Jeuland M (2011) Creating incentives for more effective wastewater reuse in the Middle East and North Africa 626, Working Paper Series, Economic Research Forum, Sanford School of Public Policy and Duke Global Health Institute, Duke University, p 33 Khatib H (2010) The water and energy nexus in the Arab region. Arab Water Report. Towards Improved Water Governance, Nairobi, UNDP (Unpublished) Khouri J (2003) Sustainable development and management of water resources in the Arab region. In: Alsharhan AS, Wood WW (eds) Water resources perspective: evaluation, management and policy, Development in Water Science 50. Elsevier, Amsterdam, pp 199–220 Lattemann S, Hopner T (2003) Seawater desalination: impacts of brine and chemical discharges on the marine environment. Balaban Desalination Publications, L’Aquila

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2  Overview on Global Water Resources

Lautze J, Stander E, Drechsel P, da Silva AK, Keraita B (2014) Global experience in water reuse, resources recovery and reuse series 4, Research Program on Water Land and Ecosystems, International Water Management Institute, USAID/USEPA, p 23 Majdalani R (2005) Challenges and opportunities in implementing integrated water resources management (IWRM) in ESCWA member countries. In: Proceedings of the Seventh Gulf Water conference on water in the GCC – towards an integrated management, Kuwait, 1:1–19 Markaz Research (2012) GCC demographic shift: intergenerational risk-transfer at play, Kuwait Financial Centre (Markaz Research), p 28 Nair M, Kumar D (2012) Water desalination and challenges. The middle east perspective: a review, Desalination and Water Treatment, Desalination Publications, Taylor and Francis Group, p 11 Nikulin G (2013) Regional climate modeling results and ensemble using RCA4.PPT the regional initiative for assessment of the impact of climate change on water in the Arab Region (RICCAR) Amman, Jordan, p 116 OHCHR (Office of the High Commissioner for Human Rights) (2010) The right to water, Factsheet. http://www.ohchr.org/Documents/Publications/FactSheet35en.pdf No. 35, p 11 Rizk ZS, Alsharhan AS (2008) Water resources in the United Arab Emirates. Ithraa Publishing and Distribution, Amman, p 624. (in Arabic) Saab N (2015) Food security in Arab countries: sufficiency, productivity and shifting dietary habits, Water Letter no. 32, CIHEAM (international Center for Advanced Mediterranean Agronomic Studies), p 5 Salih A (1997) UNESCO’s international hydrological programme and sustainable water resources management in the Arab Region. In: The Third Water conference, WASTA, Muscat, Sultanate of Oman, 8–13 March 1997 Sato T, Qadir M, Yamamoto S, Zahoor A (2013) Global, regional, and country level need for data on wastewater generation, treatment, and use. Agric Water Manag 130:1–13 Scott C, Drechsel P, Raschid-Sally L, Bahri A, Mara D, Redwood M, Jimenez B (2010) Wastewater irrigation and health: challenges and outlook for mitigating risks in low-income countries. In: Wastewater irrigation and health: assessing and mitigating risk in low-income countries. Earthscan/International Development Research Centre (IDRC)/International Water Management Institute (IWMI), London/Ottawa/Colombo, pp 381–394 Shiklomanov IA (2000) Appraisal and assessment of world water resources. Int Water Resour Assoc Water Int 25(1):11–32 Shiklomanov IA, Rodda J (2003) World water resources at the beginning of the 21st century. UNESCO, Paris Taylor RG, Scanlon B, Döll P, Rodell M, Beek RV, Wada Y, Longuevergne L, Lablanc M, Famiglietti JS, Edmunds M, Konikow L, Green TR, Chen J, Taniguchi M, Bierkens MFB, MacDonald A, Maxwell RM, Yechieli Y, Gurdak JJ, Allen DM, Shamsudduha M, Hiscock K, Yeh PJF, Holman I, Treidel H (2013) Ground water and climate change. Nat Clim Chang 3:322–329 Terink W, Immerzeel WW, Droogers P (2013) Climate change projections of precipitation and reference evapotranspiration for the Middle East and Northern Africa until 2050, Int J Climatol, Royal Meteorological Society, p 18 Todd DK (1980) Groundwater hydrology, 2nd edn. Wiley, New York Trenberth KE, Smith L, Qiguo D, Fasullo J (2007) Estimates of the global water budget and its annual cycle using observational and model data. J Hydrometeorol—Special Section 8:758–769 UN (United Nations) (2007) The United Nations world water development report 2015. Water in a changing world, UNESCO5 3, place de Fontenoy, 75352 Paris 07 SP, France UN (United Nations) (2014) Water and energy. The United Nations water development report 2 volumes. United Nations Water Assessment Program. UNESCO, Paris UN (United Nations) (2015) The United Nations world water development report 2015: water for a sustainable world, UNESCO 7, place de Fontenoy, 75352 Paris 07 SP, France UNDP (United Nations Development Program) (2013) Water governance in the Arab Region: managing scarcity and securing the future. Regional Bureau for Arab States, New York, p 146

References

61

UNEP-MAP/MED PO (2003) Sea water desalination in the mediterranean: assessment and guidelines. MAP technical reports series no. 139. Athens, United Nations Environment Programme (UNEP)-Mediterranean Action Plan (MAP). http://195.97.36.231/acrobatfiles/ MTSAcrobatfiles/mts139eng.Pdf UNESCO (2003) United Nation water development report—water for people, water for life, p 544 UNESCO (2015) Contribution to the United Nations world water development report 2015. Facing the challenges—case studies and indicators, vol 2, UNESCO 7, place de Fontenoy, 75352 Paris 07 SP, France, p 61 UNESCWA/BGR (United Nations/Economic and Social Commission for Western Asia/ Bundesanstalt für Geowissenschaften und Rohstoffe) (2013) Inventory of shared water resources in Western Asia. UNESCWA, Beirut UNESCWAa (2013) Progress made in the development of a legal framework for shared water resources in the Arab Region, Beirut. Committee on Water Resources, UNESCWA Vrba J (2004) The world’s groundwater resources: contribution to chapter 4 of WWDR 2. International Groundwater Resources Assessment Center, Utrecht, p 10 White WR (2010) World water: resources, uses, and the role of man-made reservoirs, 2010. Foundation for Water Research, Allen House, The Listons, Marlow Bucks, p 60 WHO (World Health Organization) (1984) WHO guidelines for drinking water quality: volume 1, recommendations, Geneva, Switzerland, p 130 World Bank (2005) A water sector assessment report on the countries of the cooperation council of the Arab States of the gulf. A report prepared for the Arab Gulf Programme for United Nations Development Organizations (AGFUND), Riyadh, Saudi Arabia. The World Bank Report No.: 32539- MNA, March 31, 2005 World Bank (2007) Making most of scarcity: accountability for better water management in the Middle East and North Africa, MENA Development Report, Washington, DC, p 227 World Bank (2009) Water in the Arab world. Management perspectives and innovations, Washington, DC, p 525 World Bank (2011) Water reuse in the Arab World from principle to practice: voices from the field, a summary of proceedings. Expert consultation on wastewater management in the Arab World, Dubai, p 37 World Bank (2012) Renewable energy desalination: Am emerging solution to close the water gap in the Middle East and North Africa. The World Bank, Washington, DC, p 201 World Bank and AGFUND (2005) A water sector assessment report on the countries of the cooperation council of the Arab states of the gulf. World Bank Report No. 32539- M. Washington, DC, USA Zekri S, Karimi A, Madani K (2014) Groundwater policing for a sustainable food supply in Oman. Paper delivered to the 41st International Association of Hydrologists (IAH) Congress. Groundwater. Challenges and strategies. Moroccan Chapter 15–19 September 2014, Marrakech

Part II

Geomorphology and Geology

Geomorphic features have a major role in determining the direction of surface-­ water flow, while the geologic conditions govern the distribution of aquifers and confining units; stratigraphic sequence can be differentiated into aquifers, aquitards, aquicludes or aquifuges. The geologic conditions also control the distribution of structural belts, which influence groundwater flow, recharge and discharge. Both geomorphology and geology determine the volumes of surface runoff, infiltration rates and quality of surface water and groundwater. Major geomorphic features in the UAE include rock outcrops of the northern Oman Mountains and gravel plains that surround the eastern and western sides of these mountains. Due to the low porosity and hydraulic conductivity of rocks forming the mountain ranges, most of the runoff makes its way rapidly towards the gravel plains in the east and west, which makes them the most important aquifers in the UAE. Sand dunes cover most of the western region stretching between the western gravel plains in the east and the sabkha deposits along the coast of the Arabian Gulf in the west. The inland sabkhas occupy topographic depressions between the sand dunes and constitute areas of groundwater discharge. Despite the absence of surface water features such as rivers and lakes, dry drainage basins interrupt the continuity of rock outcrops and gravel plains through a network, and these basins may carry water during the rainy seasons. The drainage patterns in mountainous regions vary from the drainage patterns in gravel plains because of the difference in lithologies and geologic structures. The geologic conditions in terms of stratigraphic sequence and main surface and subsurface geologic structures are described. The hydrogeological characteristics of the lithological units in terms of their relationship to water are also discussed. The main aquifer in Wadi Al Bih basin of Ras Al Khaimah ranges in age from the Permian to the Triassic. The limestone belonging to the Eocene age is the main aquifer in Jebel Hafit, Al Ain Region of the Abu Dhabi Emirate. The gravel deposits and sand dunes of the Quaternary age make up the most important aquifers in many parts of the UAE.

Chapter 3

Geomorphology and Geology and Their Influence on Water Resources

Abstract  Geologic conditions govern the distribution of aquifers and confining units and their outcrops, while geomorphic features control the directions of surface-­ water flow. Usually any stratigraphic sequence can be differentiated into aquifers, aquitards, aquicludes and aquifuges. Geologic conditions also control the distribution of structural belts, which influence groundwater flow, recharge and discharge. Both geomorphology and geology determine the volumes of surface runoff and amounts and rates of infiltration, in addition to surface-water and groundwater quality. The major geomorphic features in the UAE include the Northern Oman Mountains (the eastern mountain ranges), gravel plains surrounding the eastern and western sides of these mountains, sand dunes, coastal areas and drainage basins. The porosity and hydraulic conductivity of the rocks forming the mountain ranges in northern and eastern UAE are very low. Therefore, most of runoff water makes its way rapidly towards the gravel plains in the east and west. The freshwater feeding these plains turns them into the most important, freshwater and renewable aquifers in the country. Sand dunes cover most of the UAE, stretching between the western gravel plains to the east and the sabkha deposits along the Arabian Gulf to the west. The coastal areas include tidal flats and coastal sabkhas. The inland sabkhas occupy topographic depressions between the sand dunes and represent areas of groundwater discharge. Despite the absence of surface-water features such as rivers and lakes, dry drainage lines interrupt the continuity of rock outcrops and gravel plains forming a network of dry drainage basins which may carry water during the rainy seasons. The drainage basins in mountains are dominated by dense trellis and rectangular patterns because of the wide variation in lithologies and presence of several geologic structures, while the basins in gravel plains are characterized by dendritic and braided patterns because of the homogeneity of plain sediments. The geologic conditions, stratigraphy and main surface and subsurface structural elements determine the hydrogeologic characteristics of the lithologic units in terms of their relationship to water. The rock sequence in the Ru’us Al Jibal area ranges from the Permian to Early Triassic and represents the main aquifer in the Wadi Al Bih basin of the Ras Al Khaimah Emirate. The Dammam Formation, belonging to the Eocene age, forms the main aquifer in Jabal ​​ Hafit. The Quaternary gravel-and-­ © Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_3

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sand aquifer is the UAE’s most important aquifer. The surface and subsurface ­geologic structures affect, either directly or indirectly, surface-water and groundwater resources. These structures include Ru’us Al Jibal, Dibba zone, Wadi Ham line, Hatta zone, Al Fayah mountains and the Al Ain mountains, as well as subsurface structures.

3.1  Main Topographic and Morphologic Features The study of topographic maps (Fig. 3.1), aerial photographs and satellite images reveals that the salient geomorphic features in the UAE include: drainage basins, coastal areas sand dunes, gravel plains and mountains (Fig. 3.2). The following is an interpretation of each of these features and their direct influence on water resources, either surface water or groundwater.

3.1.1  Mountains

53°

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Ajman Sharjah Dubai

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Rizk and Alsharhan (2003) stated: “The eastern mountain ranges in the UAE extend for 155 km between Sha’am in the north and Al Ain area in the south, with an average width of 10 km in the north, 38 km in the middle and 27 km in the south. The

25°

15

0

Kalba

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Fig. 3.1  Simplified topographic map of the United Arab Emirates

55°

56°

3.1  Main Topographic and Morphologic Features

Gravel Plains

Ancient and Recent Dunes Coastal Sabkhas

ARABIAN

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Fujairah

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Linear Dunes, Star Dunes and Playa Deposits

25°

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25°

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Fig. 3.2  Geomorphologic map for the United Arab Emirates. (Simplified from the UAE National Atlas 1993)

elevations of the mountain peaks vary between 500 and 900 m above meam sea-­ level (amsl). Some salient peaks, however, may reach an elevation of 2000 m amsl.” The UAE’s eastern mountains can be divided into the Ru’us Al Jibal massif in the north, Dibba zone in the middle and the eastern mountain ranges in the south (Finzi 1973). These structural ridges forming the mountain ranges have a major upwarp zone. They form the watershed areas for all of the wadis that are directed either to the Gulf of Oman in the east, or the Arabian Gulf in the west. These ridges are separated by the Dibba transform fault zone into two portions. The northern portion is essentially underlain by carbonate rocks, with vegetation occurs mainly in the wadis, as indicated by karst development and inherited from previous wet periods. The morphology of these carbonate rocks (forming the mountainous areas in Ras Al Khaimah) display examples of fold morphology, such as erosional depressions on the crests, monoclonal dip slopes, cuestas facing west and fold escarpments in the direction of the sea to the west associated with faulting and steep dip slopes. The southern portion of these ridges or mountain range is essentially underlain by igneous and metamorphic rocks (ophiolite) and a Hawasina Series of sedimentary rocks. These rocks form a broad arch dissected by a number of fracture lines such as wadi Sinnah, wadi Shimal and Masfut. In these structural ridges, the slopes are gentler and the surface is dissected by drainage patterns. The morphology of the

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Photo 3.1  Outcrops of limestone rocks belong to the Ru’us Al Jibal massive and represent the northern wall of Wadi Al Tawiyean. The body of the Wadi Al Tawiyean dam is in the lower right section of the photograph

drainage lines is the common occurrences of alluvial terraces rising 20–25 m above the present wadi beds. The rock sequence of the Ru’us Al Jibal massif consists predominantly of a carbonate sedimentary sequence that ranges in age from the Triassic to the Permian (Photo 3.1), and is characterized by broad folds, step faults and complex thrust anticlines. The Dibba zone is an elongated northeast–southwest trending topographic depression, separating the rock sequence of Ru’us Al Jibal on the upper left side from the Semail ophiolites sequence on the lower right side. The Semail ophiolites is called the eastern mountain ranges in the UAE and is mainly located in Fujairah, Khor Fakkan and Dibba areas. The sequence is repeated because of the presence of faulting. The ophiolite complex is divided, from top to base, into: sheeted dyke complex and extrusive lava, fine-grained gabbros, coarse-grained gabbros, layered peridotite and an ultramafic mantle sequence (Photos 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, and 3.10). There is a group of limestone mountains south of the ophiolite belt, such as the Al Fayah Mountains. Al Fayah is a group of folds located west of the eastern mountain ranges and is separated from it by the western gravel plain. The Al Fayah Mountains have a north–south trend and are composed of limestone rocks, while its core is occupied by allochthonous ultramafic rocks. Jabal Al Rawdah is a plunging anticline located on the western side of the Dibba zone. The mountain is composed of limestone rocks belonging to the Hawasina Group, which is unconformably overlain by limestone sequence ranging in age from the Triassic to the Upper Cretaceous. In the Al Ain area, the mountains encountered include: Jabal Hafit, Jabal Al Oha, Jabal Al Zarub, Jabal Malaqet and Jabal Mundassah. The mountain has a whale-­ back form, and its rocks belong to the Tertiary age (Whittle and Alsharhan 1994).

3.1  Main Topographic and Morphologic Features

69

Photo 3.2  Ophiolite rocks represent a part of the northern Oman Mountains. These rocks are in the entrance of Wadi Shi, Fujairah Emirate, which has palm trees in the middle and runs along the unpaved track on the right of the photo

Photo 3.3  Ophiolites are part of northern Oman Mountains. These rocks are in the entrance of Wadi Shi, Fujairah Emirate, which has palm trees in the middle and runs along the unpaved track on the left of the photo

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Photo 3.4  Joint sets in the upper photograph and bedding plans in the lower one affect the ophiolitic rocks forming the right wall of Wadi Shi, Fujairah Emirate

Photo 3.5  Ophiolite rocks represent a part of the northern Oman Mountains in the United Arab Emirates. It forms the ophiolite aquifer in the Eastern Region. Joint sets and other structural elements increase the porosity and specific capacity of the aquifer

3.1  Main Topographic and Morphologic Features

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Photo 3.6  Ophiolite rocks forming the right wall of Wadi Shawkah. Joint sets and other structural elements increase the porosity and specific capacity of the ophiolite aquifer

Photo 3.7  Clayey deposits resulting from weathering of ophiolite rocks, fill the opening caused by geologic structures and reduce the aquifer’s hydraulic conductivity

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.8  The white magnesite veins form as a result of weathering of ophiolites. The magnesite fill the openings caused by geologic structures and reduce the aquifer’s hydraulic conductivity

Photo 3.9  Ophiolite rocks represent a part of northern Oman Mountains. The rocks are overlooking Ain Al Ghomour, Fujairah Emirate, which is surrounded by palm trees on the lower left of the photograph

3.1  Main Topographic and Morphologic Features

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Photo 3.10  Ophiolite rocks represent a part of the eastern mountain ranges in the UAE. The rocks make up the right wall of Wadi Shawkah, which runs along the asphaltic road on the lower right of the photograph

The length of Jabal Hafit is 29 km, 15 km of which are within the UAE and the rest are in Oman. It has an average width of 5  km and a maximum elevation of 1160 m (Photos 3.11, 3.12, 3.13, and 3.14). The dip angle of the eastern limb is high varying between 60° and 80°, while the dip angle of the western limb is low ranging from 22° to 26° (Hunting 1979). According to Alsharhan et al. (2001): “Jabal Malaqet and Jabal Mundassah are considered a part of the eastern mountain ranges in the UAE, and are located approximately 17-km east of Jabal Hafit. The two mountains form asymmetrical anticlinal structure with the eastern limbs forming the main part of the exposure. The western limbs are composed of discontinuous, low relief outcrops (Photo 3.15). Jabal Al Oha lies 8 km northeast of Al Ain city”.

3.1.2  Gravel Plains The gravel plains consist of a large number of combined alluvial fans along the base of the eastern mountain ranges, underlain by poorly stratified gravel detritus. Sheet floods play a significant role in their development. The surface in these plains is dissected by a wadi system, and the direction of flow changes from original latitudinal attitudes to the present, presumably as a result of the sinking of structural ridges in these areas.

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.11  Rock outcrops in Jabal Hafit, as it seems from the Wagan–Al Ain road on the lower left of the photograph

Photo 3.12  Rock outcrops in Jabal Hafit in Al Ain, as can be seen on the right side of the wadi, which runs across the middle of the photograph

3.1  Main Topographic and Morphologic Features

75

Photo 3.13  Rock outcrops in Jabal Hafit at the entrance of Mubazzarah area, north of Jabal Hafit. The green color is spreading as can be seen on the lower left of the photograph

Photo 3.14  Limestone rock outcrops near the top of Jabal Hafit. The photo shows karst features resulting from chemical weathering of the mountain. This phenomenon increases secondary porosity and the aquifer’s storage

76

3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.15  Outcrops of limestone rocks, east of Al Ain city near Al Buraimi. The sand dunes around these mountains receive recharge from rains falling on these mountains

Gravel plains bound the eastern mountain ranges in the UAE on both the eastern and western sides. The eastern gravel plain is a narrow strip, about 4–10 km wide and 70 km long. The plan extends between the Gulf of Oman coast and the eastern mountain ranges (Fig.  3.2; Photos 3.16, 3.17, 3.18, 3.19, and 3.20). The eastern coastal plan extends between Dibba in the north and the UAE–Oman borders in the extreme south. The western gravel plains extend 160  km as a long, strip from Sha’am in the northeast of Al Ain city in the south (Ghoneim 1991). The plains exist at the outlets of the main wadis draining the eastern mountain ranges, which have the main effect on their shape and width. The western gravel plans extend as an extensive, flat and featureless surface between the eastern mountain ranges and sand dunes in the western UAE (Photo 3.21). The gravel plains are composed of alluvial sand and gravel, transported by flood water moving across the drainage basins dissecting the eastern mountain ranges, which gradually decrease in size from east to west. Sand dunes and the Al Fayah Mountains locally interrupt the continuity of the western gravel plain. Alluvial deposits usually dominate the piedmont plains, which fringe from the eastern ­mountain ranges and the isolated mountain chains, such as the Al Fayah Mountains in Sharjah and Jabal Hafit in Al Ain. The Al Jaww gravel plain in the eastern part of Al Ain City extends between the eastern mountain ranges in the east and Jabal Hafit in the west. The plain consists of gravel and sand washed by wadis draining the mountains. The size of wadi deposits decreases from large rock masses and cobbles in the east to sand and silt in the west.

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77

Photo 3.16  The UAE’s eastern coastal plain. It extends between the eastern mountain ranges, in background of the photograph, and the Gulf of Oman. Notice the concentration of farms, which appear as a green line, at the outlets of main wadis

Photo 3.17  The eastern coastal plain extends between the eastern mountain ranges and the Gulf of Oman. Its width varies between 4 and 8 km. Notice the concentration of farms at the outlets of main wadis, which appear as green line in the middle of the photograph

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.18  Sediments of the eastern coastal plain range from large rock masses close to the mountains, and sand, silt and clay near the Gulf of Oman in UAE

Photo 3.19  Outlet on an active drainage basin, in the northern Oman Mountains in the UAE, entering the eastern coastal plain

3.1  Main Topographic and Morphologic Features

79

Photo 3.20  The western gravel aquifer, near the Al Fayah Mountains in Al Ain Region, between the mountains in the east and sand dunes, in the lower half of the photograph, in the west

Photo 3.21  Active, linear sand dunes on the right side of the Al Ain–Al Wagan road

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3  Geomorphology and Geology and Their Influence on Water Resources

Several alluvial channels draining the eastern mountains disappear under sand dunes in the west. The Al Jaww plain deposits are a typical example of alluvial deposits, which are composed of pebbles and grains of gabbro, serpentine, limestone and chert, cemented by fine calcareous silt. The cementing materials largely influence the effective porosity and hydraulic conductivity of the alluvial deposits. In some areas, however, these sediments are unconsolidated or partially cemented by calcite, which makes it a good, high-quality aquifer. The desert-plain deposits fill the topographic depression between sand-dune ridges in the Western Region of the UAE. These deposits are composed of silt, rich in calcareous cementing materials and include cross-bedding structure. This structure might suggest that some desert-plain deposits represent old sand dunes, which became cemented as a result of accumulation of salts with the elapse of time. This process can be accompanied by direct evaporation of groundwater from a shallow water table during past geologic times. In some desert holes, the desert-plain deposits are composed of gravel, calcrete, nodular limestone and calcareous silt. The calcrete deposits are white, calcareous, unstratified and include scattered grains of silica and other rock fragments and are predominantly coated with a layer of iron and manganese oxides.

3.1.3  Sand Dunes About three-fourths of the ground surface of the UAE is covered by dune sands. The dunes occupy a triangular area: its apex lies in the north at Ras Al Khaimah, its base draws the UAE–Saudi Arabia border in the south, its eastern side runs parallel to the pediment plains and its western side is parallel to the western coastal area. The sand mass in the UAE is a part of the Rub al Khali desert, which extends beyond the borders into the Sultanate of Oman and Saudi Arabia. Landsat satellite images show that most of the UAE is occupied by various types of sand dunes and that the elevation of these dunes ranges from a few meters above sea level in the north and along the Arabian Gulf coast to 200-m above sea level in the Liwa oasis in the southern UAE. Embabi (1991) used satellite images to study the dune types, patterns, generations and the factors affecting sand supply. The most common dune types in the UAE include linear dunes (Photos 3.22 and 3.23), barchan and barchanoid dunes, transverse dunes and star dunes (Fig.  3.3). The dunes include both simple and compound patterns, which are mainly controlled by sand supply, meteorology, topography, lithology and geologic structure. Linear dunes are dominant in the Western Region of the UAE and extend northeast–southwest. The color of the dune sands becomes lighter westwards, where the contribution of dark minerals in the ophiolite outcrops becomes less, and the percentage of carbonate and evaporite minerals gives the dunes a light color. The star dunes exist in the area southwest Al Ain (Photo 3.24), along with other dunes types, such as barchan and linear dunes. Star dunes occupy most of the Liwa

3.1  Main Topographic and Morphologic Features

81

Photo 3.22  Active, linear sand dunes on the right side of the Al Ain–Al Wagan road. Notice the alternation of dune lines and flat, interdune areas, which are usually covered by farm vegetation

Photo 3.23  Active, star sand dunes on the right side of the Al Ain–Al Wagan road

oasis, which represents the northeastern tip of Rub al Khali desert in the Arabian Peninsula. Some star dunes may reach elevations over 100-m above the surrounding ground surface. Star dunes are the most developed dune type because of the availability of sand supply.

53°

52°

55°

54°

Old Dunes Covered by Recent Dunes

Ras Al Khaimah

Small and Large Parallel Linear Dunes

Diba

Small and Large Transverse Ridges

Umm Al Quwain

Clustered Mega Barchans Barchan Dunes

ARABIAN

GULF

Sabkhat Matti 25°

56°

Ajman Sharjah Dubai

GULF OF OMAN

3  Geomorphology and Geology and Their Influence on Water Resources

OM AN

82

Fujairah

Star Dunes

Kalba

25°

Sand Sheets Mountainous Areas Beach Deposits

Abu Dhabi

OMAN

Al Ain

24°

24°

Bu Hasa

I UD SA

UNITED ARAB EMIRATES

N

Liwa 23°

23°

ARAB 52°

50 km

IA 53°

54°

55°

56°

Fig. 3.3  Map showing the distribution and types of sand dunes in the United Arab Emirates. (Modified from the UAE National Atlas 1993)

Photo 3.24  Sand dunes on the right side of the Sharjah–Al Dhaid road, indicate a shallow aquifer, where the roots of palm trees possibly reach the groundwater table

3.1  Main Topographic and Morphologic Features

83

Photo 3.25  Coastal sand dunes on the right side of the Ras Al Khaimah–Sharjah road. Sabkha deposits separate the coastal dunes and internal sand dunes

The environment leading to the origin of star dunes is characterized by multiple wind directions. The interdune areas, between star dunes in the Liwa oasis, are the best for farming due to the availability of suitable soil and shallow groundwater resources, which are only a few meters below the land surface (Photo 3.25). The colors of dune-forming sands vary from dark brown, reddish, yellowish to white, in the order mentioned, from the mountains outcrops towards the Arabian Gulf in the west (Photo 3.26). Embabi (1991) described: “The dune sands are mostly composed of sand-size quartz, with a low percentage of carbonate sand near coastal areas, or a low percentage of dark-minerals sand derived from mafic and ultramafic rocks in areas adjacent to the eastern mountain ranges in the UAE. The roundness and sorting of the dune sands increase with increasing the length of its journey from the source (Photos 3.27 and 3.28). In the Western Region of the UAE, sand dunes represent a free, shallow aquifer, and its water is used for agricultural and domestic purposes in Liwa oasis and Bu Hasa oil field (Al Amari 1997). The sand dunes along the coast of the Arabian Gulf are old and covered by natural vegetation which limits their movement to a large extent (Photo 3.29). These dunes take a northeast-southwest direction, perpendicular to the prevailing wind direction affecting the western coastal region of the UAE; the “Shamal” winds”. Accumulations of dune sands form a sandy desert, and sand seas cover a great part of UAE, reaching up to 80% or more. They are almost fixed by a relatively dense cover of short shrubs, such as south of Jabal Al Fayah. The interdunal depressions take the form of deflated plains with common salt-tolerant plants and locally scattered and scanty cultivation with date palms and alphalpha such as in the Liwa area.

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.26  One of the active barchan dunes on the right side of the Al Dhaid–Sharjah road. Ripple marks on the dune surface help to determine the prevailing wind direction

Photo 3.27  Ripple marks in this photograph show that the prevailing wind direction is from left to right. Sands of these dunes are well-sorted and rounded, facilitating large infiltration rates of rains falling on these dues towards groundwater

South and east of Dubai, Abu Dhabi and Ras Al Khaimah, there is a series of calcareous sandstone ridges, and towards the Arabian Gulf these ridges disappear completely and drowned underneath the sea. Between Al Ain and Abu Dhabi and south of Dubai, there is a series of flat-topped white hills (or eroded mesas) of

3.1  Main Topographic and Morphologic Features

85

Photo 3.28  Old, fixed sand dunes as a result of growing vegetation on their surface, which limits sand movement to a great extent. These dunes are on the right side of the coastal road between Umm Al Quwain and Sharjah

Photo 3.29  Contact line between old sand dunes, covered by natural vegetation in the upper part of the photograph, and coastal sabkhas along Arabian Gulf coast between Ras Al Khaimah and the Umm Al Quwain road

poorly consolidated sandstone and limestone. There is also a series of small folded ridges near Jabal Hafit in Al Ain which display folded morphology, with the surface underlain by weathering resistant rocks. Mud flats and playas are associated with the main drainage lines, and the surface of these features are either exposed or concealed underneath the sand dunes.

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3  Geomorphology and Geology and Their Influence on Water Resources

3.1.4  Coastal Areas The coastal areas of the UAE display a variety of land forms which are related to two main processes: (a) aggradational landforms and (b) degradational landforms. The aggradational landforms are typified by an onshore sandy beach, nearshore spits and lagoons, tidal flat sabkhas, alluvial deposits, which are drifted directly into the offshore water, and coastal dunes. The degradational landforms are characterized by coastal wave-cut cliffs, an absence of beach deposits, development of fjord like embayments and the encroachment of inland dunes to the coast. The UAE’s western coast comprises tidal flats dominated by sabkha deposits, extending along the present-day coastline of the Arabian Gulf (Photos 3.30, 3.31, 3.32, and 3.33). Sabkha deposits are divided into two types; coastal sabkhas and inland sabkhas (Fig. 3.1). The coastal sabkhas are the saline sediments remaining after evaporation of seawater (Patterson and Kinsman 1981; Sanford and Wood 2001; Wood et al. 2002, 2005; Kendall and Alsharhan 2011). The inland sabkhas are mainly interdunal areas where groundwater discharge occurs by evaporation from a very shallow water table (Hutchinson 1996). Inland sabkhas occur where the channel of a main wadi enters sand dunes, or where the groundwater table intersects the land surface or sometimes above it. Evaporation of groundwater leads to formation of inland sabkhas (Fig. 3.1). Sabkha areas can be distinguished on aerial photographs and satellite images as light-­ colored areas near the outlets of main wadis, or where the groundwater directly evaporates from desert depressions or from interdune areas (Photo 3.34). The sabkha consists mainly of carbonate sediments of sandy-silt size with anhydrite and halite interbeds (United Nations 1982) and forms in areas where brines are

Photo 3.30  Coastal sabkhas occupy low areas between coastal sand hills. The photograph also shows the white coastal sand dunes in the upper part of the photograph

3.1  Main Topographic and Morphologic Features

87

Photo 3.31  The clayey, highly saline sabkha deposits are rich in coastal life forms. This sabkha lies along the Arabian Gulf coast between the cities of Umm Al Quwain and Ajman

Photo 3.32  Saline deposits, a part of coastal sabkhas, on the right side of the coastal road between Ras Al Khaimah and Umm Al Quwain. The trees in the photograph are salt-tolerant mangrove trees, growing in coastal areas in the United Arab Emirates

one or two meters under the ground surface. The eastern coast is composed of sand and gravel and contains freshwater which drains the main wadis toward the sea. Several wadis such as Wadi Ham drains eastwards to the Gulf of Oman and can undergo flash floods which do not last longer than a few hours.

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.33  Example of inland sabkha in Al Jurf area, Ajman Emirate. The water table is very close to the land surface, causing evaporation directly from the groundwater

Photo 3.34  Wadi terraces are alluvial deposits with good soil and high groundwater potential. Wadi Ham terraces are intensively cultivated as shown in this photograph

3.1.5  Drainage Basins There are numerous dry drainage basins that can carry water during occasional heavy rainstorms. Streams discharging these basins start in the eastern mountainous region and drain either eastward into the Gulf of Oman or westward in the direction of the Arabian Gulf.

3.2  General Overview of Aquifer Systems

89

One of westerly-directed basins reaches the Arabian Gulf in the northwest, while the other basins end in the gravel plains and sand-dune fields in the middle or in the west and southwest. The flash flooding occurs over drainage basins when heavy rainstorms pour large volumes of water over short periods of time on igneous and metamorphic rocks of low porosity and hydraulic conductivity. Rainstorms can also cause groundwater recharge under favorable conditions. The eastern mountains are dissected by 70 drainage basins (Fig. 3.4), 58 of which lie within the UAE, with the rest located near the UAE–Oman border (Photos 3.35, 3.36, 3.37, 3.38, 3.39, and 3.40). The area of these basins ranges from 5 km2 (Wadi Dhanna) in Fujairah to 475 km2 (Wadi Al Bih) in Ras Al Khaimah. Among these basins, 54 have areas more than 10 km2, indicating their capability of carrying large amounts of flood water, especially the basins of the southern region which drain low porosity and low hydraulic conductivity igneous and metamorphic rocks (Rizk et al. 1997).

3.2  General Overview of Aquifer Systems Rizk and Alsharhan (2003) explained: “The main aquifer systems in the UAE are: the limestone in the north, east and west; ophiolite aquifer the east; eastern and western gravel aquifers, surrounding the eastern mountain ranges from the east and west, and sand dune aquifers in the Western Region of the Abu Dhabi Emirate (Fig. 3.5)”. The Wadi Al Bih limestone aquifer is the main source of groundwater for Ras Al Khaimah City. For this reason, the aquifer’s hydrogeology, hydrogeochemistry and isotope hydrology have been the subjects of detailed studies. Studies also evaluated the suitability of the groundwater in the aquifer for various uses. In the Al Ain area, studies covered the geologic conditions, chemical characteristics and isotope hydrology of the Dammam aquifer, which produces about 7.7  Mm3/year of hot, salty water of therapeutic value. The area has been developed as a touristic site and for recreation. In the western UAE, the limestone rocks of Dammam and Umm Er Radhuma and Simsima formations serve as highly saline aquifers of salinities varying between 70,000 and 230,000  mg/L.  Water from these aquifers is  injected oil fields to maintain reservoir pressure. The results of investigating the northern limestone aquifer of the Ras Al Khaimah Emirate, the eastern limestone aquifer in Jabal Hafit at Al Ain area, Eastern Region of Abu Dhabi Emirate, and limestone aquifer in the Western Region of Abu Dhabi Emirate will be discussed elsewhere in this volume. The Semail ophiolites dominate the northern and eastern mountain ranges, extending between the southern Dibba Zone in the north and the UAE-–Oman borders in the south. The Semail ophiolite aquifer has low productivity, but can be developed into a good aquifer where the intensity of joints, folds, faults and f­ ractures increases the secondary porosity and hydraulic conductivity. The groundwater quality in this aquifer is generally good, having low salinity and short residence time.

90

3  Geomorphology and Geology and Their Influence on Water Resources 55o 45`

26o 00`

56o 00`

56o 15`

26o 00`

1 2

ARABIAN GULF

OMAN

18 Ras Al Khaimah 45`

Wadi Naqab

3

Umm Al Qaiwain

4

Wadi Al Tawyen

Wadi Baseirah

19

Wadi Kub

30`

6

5

13 Wadi Zikt

Wadi Wire‘ah

7

24

Masafi

OMAN

Al Dhaid 25o 15`

9 Water Divide

Wadi Al’ Ishwani

Main City Major Dam Road

22

15

8

Ash Shiweb Dam 55o 45`

25o 00`

12

30 km

Wadi Qor Wadi Hadf

24o 45`

Fujairah

Kalba

LEGEND

20

27 25o 15`

Wadi Ham

16

10

25o 30`

Khor Fakkan

17 10

25o 45`

14

Wadi Adhan

Wadi Al Ghel

GULF

Diba

25o

0

OF OMAN

Wadi Al Bih

25o

Wadi Ghalfa 56o 00`

Masfut

OMAN 56o 15`

24o 45`

Fig. 3.4  Major drainage basins and locations of groundwater-recharge dams in the Eastern Region of the United Arab Emirates

However, the water may be hard-to-very hard as a result of dissolution of calcium and magnesium ions dominant in the basic and ultrabasic rocks in the ophiolites sequence. The ophiolite aquifer and the linear features affecting aquifer and their geologic and hydrogeologic influence on groundwater flow, level, chemistry and quality will be discussed separately.

3.2  General Overview of Aquifer Systems

91

Photo 3.35  Drainage basins in eastern UAE are dry most of the year. However, they must be kept clean because it becomes active in the rainy season and carries flood water, which recharges groundwater

Photo 3.36  Wadi Shawhak dam in Ras Al Khaimah Emirate is one of the most successful recharge dams in the UAE and its reservoir is usually filled with flood water one than once a year

Gravel aquifers account for most of the fresh groundwater reserves in the UAE. These aquifers surround the eastern mountain ranges in the UAE from the east and west. In the east, the eastern gravel aquifer extends from Dibba in the north to Kalba in the south. The geomorphology, geology, hydrogeology, water chemistry and isotope hydrology of the eastern gravel aquifer, as well as groundwater quality and suitability for various uses, will be discussed in detail in Chap. 11.

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3  Geomorphology and Geology and Their Influence on Water Resources

Photo 3.37  Alluvial deposits in Wadi Ham indicate a good aquifer, which is recharged from the rains falling on the mountains surrounding the wadi floor

Photo 3.38  Earth breaker in Wadi Safad of Fujairah Emirate. Notice the accumulation of dry clays with mud cracks retained behind the breaker after flood water infiltrated or evaporated

The western gravel aquifer extends between Sha’am in the north and east of Al Ain City in the south, covering the area between the mountains in the east and sand dune fields in western UAE. The aquifer also extends under the sand dunes in many areas, in the form of ancient buried alluvial channels of high-quality groundwater and potentiality. Several of these paleochannels occur in and around the Al Ain Region of the Abu Dhabi Emirate.

3.2  General Overview of Aquifer Systems

93

Photo 3.39  Wadi Tawiyean, as seen from the dam site. The limestone outcrops of the wadi witness the extensive crushing activities needed for cement factories

Photo 3.40  Wadi Al Mawrid showing the baseflow water in the wadi floor constituting a continuous water supply feeding Falaj Al Mawrid

The Quaternary sand dunes in western UAE were named by the authors of “Liwa Quaternary sand aquifer“. Their studies provide in-depth discussion of the hydrogeology, hydrogeochemistry and isotope hydrology of the aquifer. Although these sand dunes cover 74% of the total area of the country, the hydrogeology of the Quaternary Liwa Aquifer still needs further detailed study, such as those in the Liwa and Bu Hasa areas.

52° LEGEND

53°

54°

Limestone aquifer S

Sand dune aquifer

Ophiolite aquifer

Coastal sabkha

Eastern gravel aquifer

Emirates

Western gravel aquifer

Main city

25°

ARABIAN

55°

56°

Ras Al Khaimah

Diba

Umm Al Quwain Ajman Sharjah Dubai

Fujairah

GULF OF OMAN

3  Geomorphology and Geology and Their Influence on Water Resources OM AN

94

25°

GULF

Kalba

Abu Dhabi

Al Ain 24°

24°

OMAN

Bu Hasa

I UD SA

UNITED ARAB EMIRATES

N

Liwa 23°

23°

ARAB 52°

53°

50 km

IA 54°

55°

56°

Fig. 3.5  Map showing the main aquifer systems in the United Arab Emirates. (After Rizk et al. 1997)

Due to the difficulty of separating the western gravel aquifer from the sand-dune aquifer in western UAE, where the two aquifers are hydraulically connected, the authors have suggested treating the sand-and-gravel sediments as a single aquifer named a “sand-and-gravel aquifer system”.

3.3  Geologic History and Hydrogeologic Characteristics The UAE is an integral part of the Arabian Peninsula and is located on the Arabian platform. The UAE’s geology is part of the platform, which is a large tectonically quiet area gradually and gently descending eastward, from central Saudi Arabia towards Qatar and the UAE, where sediments ranging in age from the Cambrian to the Quaternary were deposited (Finzi 1973; Fig. 3.6). Tectonically, the UAE is bounded from northwest by the Qatar Arch and from the north and northeast by the mobile belt of Oman Mountains and Zagros Mountains in Iran. The Arabian platform was affected by slow-to-mild tectonic movements that led to the formation of depositional basins, namely, the Rub al Khali and basin and Ras al Khaimah basins (Fig. 3.7). The northern part of the Rub al Khali basin is characterized by continuous, interrupted subsidence and sedimentation over successive geological times. Electromagnetic geophysical surveys indicate that the thickness of sedimentary rocks in the northern part of Rub al Khali basin varies between 6700 and 8500 m.

3.3  Geologic History and Hydrogeologic Characteristics 56°

55°

54°

Ras Al Khaimah

Gypsum Deposits

Diba

Sabkha Deposits

Umm Al Qaiwin

TERTIARY Marl and Limestone CRETACEOUS 25° Limestone, Marl and Sandstone

Arabian

Gulf

Ajman Sharjah Dubai

Fujairah

Gulf of Oman

53°

52o

OM AN

52°

QUATERNARY Eolian Sand Surfacial Gravels

95

25°

Semail Ophiolite Kalba

Hawasina Complex JURRASSIC Musndam Limestone TRIASSIC Triassic and Permian Rocks

OMAN

Abu Dhabi

Al Ain

24°

24°

N

Bu Hasa

U SA DI

UNITED ARAB EMIRATES Liwa

23°

ARAB 52°

53°

23°

IA

50km 54°

55°

56°

Fig. 3.6  Simplified geologic map of the United Arab Emirates. (Modified from the UAE National Atlas 1993)

The Ras Al Khaimah basin was characterized by fast subsidence during the Tertiary period, where the thickness of sediments reaches more than 3000 m in the central part of the basin. The subsurface stratigraphic sequence, as well as the aquifers and confining units, has been identified by data derived from wells drilled in various parts of the region (Fig. 3.8). The regional geologic structures have a definite role in groundwater flow and recharge. Most of the sediments in this region are carbonates with clastic rocks and evaporite layers, reflecting cycles of sea transgression and regression and the climate that prevailed during the geologic past. All these factors have determined the distribution and occurrences of oil, gas and groundwater in the region.

3.3.1  Paleozoic Deposition and Water Occurrences The oldest rocks in the UAE are exposed in Jabal Al Dhanna, having been brought to the surface by salt diapers. The Silurian and Devonian sediments have been encountered only in the deepest well drilled in offshore Abu Dhabi. The Unayzah

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3  Geomorphology and Geology and Their Influence on Water Resources

MED. SEA

IRAN

N IA AB F AR GUL

GULF OF OMAN

Riyadh

Arabian Shield

UAE

RE D Hq

f

SE A

ARABIAN SEA

500 km

Precambrian

Rub Al Khali basin

Zagros basin

Fars platform

Ras Al Khaimah basin

Paleohigh (Arch)

Thrust zone

Fig. 3.7  Geologic boundaries and depositional basins in the Arabian Peninsula. (Alsharhan 1989)

Formation is composed of 205–255-m thick clastic sequence penetrated by deep oil wells drilled in the Abu Dhabi Emirate (Alsharhan and Kendall 1986; Alsharhan 1994). The Khuff Formation is composed of a 500–900-m thick sequence of dolomite, limestone and anhydrite of the middle to late Permian (Fig. 3.8). The Permo-Triassic Ru’us Al Jibal karst limestone aquifer has an average saturated thickness of 250 m and a hydraulic conductivity (K) varying between 32.7 and 67.3 m/d. The aquifer has high transmissivity (T = 1324–2729 m2/d) and a low storage coefficient (Sc) (0.001–0.002), and provides the main source of water in the Ras

FARS

NEOGENE

MIOCENE

BARTONIAN

THANETIAN

ARUMA

LATE

MAASTRICHTIAN

MIDDLE EARLY

WASIA

1800

Biyadh- Wasia aquifer. Major aquifer in eastern and northeastern Saudi Arabia. The aquifer Transmissivity (T) = 2 0.003 m /sec, Storativity (S) = 0.004 and effective porosity (Өe) = 0.2.

2100

MISHRIF

Sulaiy - Yamama - Buwaib aquifer. Constitute an aquifer in in central Saudi Arabia, with TDS contents = 1000 to 3000 mg/L.

APTIAN

SHUAIBA

2700

KHARAIB

Dhruma aquifer. The Middle Transmissivity Jurassic is a good aquifer in Saudi Arabia. The aquifer’s T ranges between 0.01 and 0.02 2 m /s.

HAUTERIVIAN

LEKHWAIR

HABSHAN

ARAB

(QATAR- FAHAHIL)

KIMMERIDGIAN

BAJOCIAN LASSIC RHAETIAN CARNIAN

ARAEJ FM.

CALLOVIAN

3000

3300

HITH

SILA

LATE EARLY MIDDLE

JURASSIC

Umm er Radhuma aquifer. The principal fresh water aquifer in eastern Saudi Arabia, while it becomes less important in Kuwait, Qatar, Bahrain, UAE and Oman, where it contains - high salinity water. Aruma aquifer. Limestone aquifer in Saudi Arabia. Groundwater quality is poor due to shale and marl intercalations.

DIYAB (DUHKAN)

3600

3900

UPPER ARAEJ

UMAINAT

LOWER ARAEJ

IZHARA HAMLAH MARRAT MINJUR

4100

4400

LANINIAN

ANISIAN

GULAILAH (JILH)

4700

5000 SCYTHIAN

SUDAIR 5300

LATE EARLY

DEVONIAN

Rus aquiclude. Composed of marl, anhydrite and gypsum. Acts as confining layer for the Umm er Radhuma aquifer in Saudi Arabia and Qatar.

1500

FIQA

OXFORDIAN

CARBONIFEROUS

Dammam aquifer. Important aquifer in all GCC countries. Groundwater flows from the east to west and northwest. In UAE, the aquifer contains brackish to saline groundwater. Variations in groundwater quality are related to lateral facies change, thickness and geologic structure.

BARREMIAN

TITHONIAN

PERMIAN

Quaternary aquifers. The most important aquifer in UAE, constitutes the eastern western gravel aquifers, sand dune aquifers. Groundwater quality is widely variable, depending on the proximity to recharge or discharge areas.

Upper Jurassic aquitards and aquifers. In Ras Al Khaimah, UAE, the Musandam Group represent the main recharge source for groundwater in Wadi Al Bih basin.

BERRIASIAN

TRIASSIC

1200

HYDROGELOGY

2400

THAMAMA

MIDDLE EARLY

CRETACEOU S

M ESOZOI C PALEOZOI C

900

97

SHILAIF/KHATTYAH MAUDDUD NAHR UMR

ALBIAN

VALANGINIAN

LATE

600

SIMSIMA

HALUL LAFFAN

SANTONIAN CONICIAN

CENOMANIAN

300

RUS UMM ER RADHUMA

DANIAN

CAMPANIAN

MISHAN GACHSARAN Lower Fars HOFUF ASMARI DAMMAM

HASA

EOCENE

PALEOGENE

EARLY OLIGOCENE

PALEOCENE

CEN OZOI C

TRETIARY

LATE

YPRESIAN

LITHOLOGY

RECENT DEPOSITS

QUATERNARY PLEISTOCENE - HOLOCENE

MIDDLE

FORMATION

DEPTH (Meter)

AGE

GROUP

PERIOD

EPOCH

ERA

3.3  Geologic History and Hydrogeologic Characteristics

EARLY

KHUFF

Minjur aquifer. The upper and lower Minjur aquifers are composed of 400 m of course to very course - grained quartz sandstone, separated by Middle Minjur shale and mudstone. The aquifer provides 90% of wadi supply for the Saudi capital 2 Riyadh. The aquifer has a good T (0.002 - 0.007 m /sec) and groundwater quality ( TDS = 1400 - 1600 mg/L). The aquifer’s storativity (S) = 0.0001, indicates a confining condition. Jilh aquifer. The aquifer thickness ranges from 360 to 400 m of sandstone and limestone interbeds, with minor gypsum. The aquifer has a secondary importance because of poor groundwater quality, which flows from southwest to northeast. The TDS increases from 800 mg/L to 12000 mg/L in the direction of groundwater flow.

Sudair aquiclude. The Early Triassic Sudair shale averages 200 m in thickness, and acts as a aquiclude for the Khuff-Tabuk aquifers in Saudi Arabia. The aquifer’s lithology is mainly brick to dark- red, massive shale with minor gypsum interbeds. Ru’us Al Jibal aquifer. The aquifer ranges in age from Permian to Early Triassic and has a thickness of 650 m. The aquifer’s hydraulic conductivity (K) ranges between 32.7 m/d and 67.3 m/d.The aquifer has high transmissivity (1324 m/d 2729 m2/d) and low storativity (0.001 - 0.002), and is the main source of water for Ras Al Khaimah Emirate, UAE. Khuff aquifer. The aquifer consists of limestone, dolomite and anhydrite, of very low effective porosity (0.03) and poor groundwater quality. The aquifer thickness averages 250 m, thickening towards the northeast to 600 m.

5600

Haushi aquifer. The Permo - Carboniferous Haushi clastic Group constitutes an important aquifer in Oman. The aquifer thins out towards the north and east .

5900

Jauf aquifer. A limestone aquifer in Saudi Arabia. The groundwater quality is good (TDS = 300 mg/L) and 2 transmissivity is low (T = 0.003 - 0.011 m /s). The aquifer storage is 0.002, where confined and 0.02, where unconfined.

HAUSHI JAUF

Marrat Aquiclude. The Lower Jurassic limestone, with shale and siltstone interbeds acts as confining layer, overlying the Minjur aquifer.

Fig. 3.8  Strategraphic sequence and hydrogeologic properties of rock units in the United Arab Emirates and the Gulf Cooperation Council (GCC) countries. (Modified from Alsharhan 1989)

Al Khaimah Emirate in the northern UAE. In Saudi Arabia, the Devonian limestone of the Jauf Formation is a fresh aquifer of good groundwater quality (TDS = 300 mg/L) and transmissivity (T) is 0.003–0.011 m2/s. The aquifer storativity (S) is 0.001 or less where the aquifer is confined, and >0.02, where the aquifer is unconfined. The Permo-Carboniferous Haushi Clastic Group constitutes an important aquifer in Oman.

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3  Geomorphology and Geology and Their Influence on Water Resources

3.3.2  Triassic Deposition and Water Potential The Triassic sediments include three formations, described by Alsharhan and Nairn (1997), from bottom to top, as: “Sudair, Jilh (Gulailah) and Minjur (Fig. 3.8). The Sudair Formation is composed of 240–275-m thick carbonate and terrigenous limestone. The Jilh (Gulailah) Formation consists of (250–310 m in marine areas of Abu Dhabi and Dubai, and 250–415 m in terrestrial areas) a sequence of dolomite, mudstones and fine terrigenous sediments. The Minjur Formation is composed of a 190-m thick coarse clastic with mudstone interbeds. The Early Triassic Sudair shale has an average thickness of 200 m and acts as an aquiclude for the Khuff and Tabuk aquifers in Saudi Arabia. The Jilh Formation is an aquifer in Saudi Arabia with a saturated thickness of 360–400 m of sandstone and limestone, with minor gypsum interbeds. The aquifer has only secondary importance because of poor groundwater quality. The groundwater flows from southwest to northeast and the TDS increases from 800 to 12,000 mg/L. The upper and lower Minjur aquifers are composed of 400 m of coarse-to-very coarse-grained quartz sandstone, separated by middle Minjur shale and mudstone. The aquifer provides 90% of the water supply for the Saudi capital Riyadh. The aquifer has good transmissivity (T  =  0.002–0.007  m2/s) and groundwater quality (TDS = 1400–1600 mg/L). The aquifer’s storage coefficient (Sc = 0.0001) indicates a confining condition”.

3.3.3  Jurassic Deposition and Water Potential In UAE, Murris (1980) and Alsharhan and Nairn (1997) documented that: “The two formations deposited in the early Jurassic, the lower is the Marrat Formation, and the upper is the Hamlah Formation, with thickness of 55–135  m (Fig.  3.8). The middle Jurassic is divided into two formations; the Izhara and the Araej Formations. The Izhara Formation is 150–235 m thick and is largely composed of argillaceous lime mudstones. The Araej Formation is split into three members of marine facies, with a total thickness of about 200 m. The early upper Jurassic Diyab Formation is composed of argillaceous lime mudstones and wackestones and is equivalent to the Dukhan limestone Formation. The Arab Formation overlies the Diyab Formation and underlies the Hith Formation, and is composed of anhydrite and carbonates. The Marrat limestone, with shale and siltstone interbeds, acts as a confining layer overlying the Minjur aquifer in Saudi Arabia. The Middle Jurassic Dhruma Formation (equivalent to the Izhara and Araej formations) is a good aquifer in Saudi Arabia. The aquifer’s transmissivity ranges from 0.01 to 0.02  m2/s. The upper Jurassic aquitards and aquifers of the Musandam Group represent the main recharge area for groundwater in wadi Al Bih basin, in Ras al Khaimah Emirate, northern UAE”.

3.3  Geologic History and Hydrogeologic Characteristics

99

3.3.4  Cretaceous Deposition and Water Potential The Lower Cretaceous Thamama Group is split into four formations (Fig.  3.8) which were described by Alsharhan (1985) and Alsharhan and Nairn (1988), in ascending order, as: “Habshan, Lekhwair, Kharaib and Shuaiba. The Habshan Formation is composed of 210–365  m thick carbonate facies sediments (Hassan et al. 1975; Alsharhan and Nairn 1986). Lekhwair Formation consists of 210–365 m thick carbonates. The Kharaib Formation is 90–110 m of limestone. The Shuaiba Formation is 45–145  m thick carbonate facies. The middle Cretaceous section is known as the Wasia Group, which is 170 m thick. The Group is divided into four formations in ascending order (Fig. 3.8). The Nahr Umr, Mauddud, Shilaif-Khatiyah and Mishrif formations (Azzam 1995). Nahr Umr Formation consists of gray to gray-green shales and mudstone with a few thin lenses of impure carbonates. The Mauddud Formation is composed of 60 m thick packstones and wackestones. The Shilaif-Khatiyah Formation is composed of silty sand, with lime mudstones. The Mishrif Formation is 265–485  m of grainstones and packstones. The Upper Cretaceous section is known as the Aruma Group consists, from base to top, of: “Laffan Formation composed 30  m thick shale with argillaceous limestone. The Halul Formation, which is composed  of interbedded calcareous shales and mudstones. The Fiqa Formation is 100–335 m thick argillaceous limestone. The Simsima Formation, 180–365  m thick, consists of packstones, wackestones and dolomitic limestone (Alsharhan 1989)”. The Lower Cretaceous formations constitute an aquifer system in central Saudi Arabia, with TDS contents of 1000–3000  mg/L.  The Middle Cretaceous Wasia Group is an aquifer in eastern and northeastern Saudi Arabia. The aquifer’s transmissivity (T) is 0.003 m2/s, its storage coefficient (Sc) is 0.004 and specific yield (Sy) is 0.2, where the aquifer is unconfined. The Upper Cretaceous limestone of the Aruma Group represents an aquifer in Saudi Arabia. But, the groundwater quality is poor because of the presence of shale and marl intercalations.

3.3.5  Cenozoic Deposition and Water Potential According to Hunting (1979): “The lower Tertiary in UAE is known as the Hasa Group, which comprises three formations; Umm Er Radhuma, Rus and Dammam (Fig. 3.8). These formations lose their rock characteristics when compared with the same rocks in Ras Al Khaimah Basin and in the extreme eastern marine areas of Abu Dhabi. The rock completely changes in the center of the depositional basin, where the first three formations are collectively known as Pabdeh Formation. The Umm Er Radhuma Formation was deposited between late Paleocene and early Eocene on unconformity surface separating the upper Cretaceous and lower Tertiary. The thickness of Umm Er Radhuma Formation is about 350 m in the northwest in

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3  Geomorphology and Geology and Their Influence on Water Resources

marine areas of Abu Dhabi, 455 m in central Abu Dhabi and 700 m in the east, and is composed of argillaceous limestone and dolomitic limestone”. Alsharhan et al. (2001) reported: “Umm Er Radhuma Formation is a main fresh water aquifer in eastern Saudi Arabia. But, it becomes less important in Kuwait, Qatar, Bahrain, UAE and Oman, where its water becomes more saline in the direction of groundwater flow”. The Rus Formation, ranges from 60 m in the northwest to more than 240 m in the middle and south, includes a thick anhydrite and limestone layer, reflecting the shallow nature of water in which it was deposited and the high temperature during this period. The massive anhydrite indicates terrestrial conditions in a supratidal environment, while the limestone and marly limestone indicate shallow marine conditions. The Rus Formation occupies the core of Jabal Hafit and is composed of thick layers of white, coarse-grained limestone. The base of the formation is unexposed, while its upper boundary consists of conglomeratic limestone, separating the Rus Formation of middle Eocene from the overlying Dammam Formation, which belongs to the middle Eocene too. The thickness of the Rus Formation in the core of Jabal Hafit is 185 m (Whittle and Alsharhan 1994). Alsharhan et al. (2001) noted that: “The Rus Formation acts as a confining layer for Umm Er Radhuma aquifer in Saudi Arabia, Bahrain and Qatar”. The Dammam Formation in Abu Dhabi is 225-m thick and is composed of calcareous limestone and marly limestone in its lower part, followed by granular limestone rich in fossils and ends with dolomitic limestone and shale in the upper part. These rocks were deposited in shallow marine shelves by waves and high currents. There are extensive outcrops of the Dammam Formation on the western edge of the eastern mountain ranges. In Jabal Hafit, the Dammam Formation represents most of the outcrops, which are composed of alternating marl and limestone layers of an average thickness of 715 m on the western limb of Jabal Hafit. The contact between the upper surface of the Dammam Formation and the overlying Asmari Formation is not clear in Jabal Hafit because of the alluvial deposits cover. Based on the Foraminifera and Nummulite fossils, the age of the Dammam Formation in Jabal Hafit varies between the middle and upper Eocene. Hassan and Al Aidarous (1985) stated: “The carbonate rocks of the Dammam Formation are the deepest rocks penetrated by water wells in Liwa and Bu Hasa areas in the Western Region of the UAE and range in thickness between 61 and 488 m, with increasing thickness from west towards east”. The rocks of the Dammam Formation are subdivided into anhydrite and dolomite in the upper part, nummulitic limestone in the middle and argillaceous and marl sediments in the lower part, with sandstone and mudstone intercalations (Whittle et al. 1996). Alsharhan et  al. (2001) pointed out that the Dammam Formation is the most important aquifer in all of Saudi Arabia, Qatar and Bahrain. However, the aquifer in the UAE is less valuable and contains poor quality water. In terrestrial areas, the Asmari Formation forms the sharp outcrops of the eastern and the western limbs of the Jabal Hafit anticline, which extends between the north-

3.4  Stratigraphic Units of Surface Outcrops

101

ern part of Al Ain Cement Factory and Wadi Tarabat. The average thickness of the Asmari Formation in Jabal Hafit is 480 m in the western limb of Jabal Hafit anticline. The upper and lower surfaces of the Asmari Formation are concealed under unconsolidated alluvial deposits. In this type of area, south of the Al Ain Cement Factory, the Asmari Formation is composed of marl containing gypsum in its lower part and limestone intercalation in its upper part (Whittle and Alsharhan 1995). In the Western Region, the carbonates of the Dammam Formation are overlain by clastic sediments belonging to the Oligocene and Miocene ages. These sediments include silt, marl with limestone and anhydrite intercalations, and its thickness varies between 130 and 160 m in Liwa (Imes et al. 1994), and 90 and 160 m in the Bu Hasa Oil Field (Al Amari 1997). In the coastal area of Abu Dhabi, the Oligocene and Miocene sediments form an unconfined aquifer. Alsharhan et al. (2001) mentioned that: “the water table is less than 1.0 m below the ground surface. But, in Liwa these sediments form a confined aquifer separated from the overlying lower Fars Formation with a thick layer of anhydrite (GeoConsult 1985). Groundwater in the Oligocene-lower Miocene sediments in this area is highly saline with salinity range of 70,000–100,000 mg/L”. The Pabdeh sediments extend from the Paleocene age to the Eocene, reaching a thickness of more than 670  m and composed of marl, shale, mudstone and little limestone and dolomite rich with planktonic foraminifera, which represents deep marine facies. The Asmari Formation is unconformably overlain by the Gachsaran (Lower Fars) Formation, with a thickness between 120 m in western Abu Dhabi and 850 m east of Dubai (Alsharhan and Nairn 1995). In surface outcrops, the Miocene sequence on the eastern limb of Jabal Hafit is composed of interbeds of gypsus marl with shale intercalations. The upper part of the sequence includes thin layers of limestone and dolomite, while the lower part consists of limestone rich in fossils. The Miocene sequence in Al Ain, from base to top, is composed of shale, gypsum, and its base is characterized by  a thick layer of hard weathering-resistant celestite, representing an excellent marker. The Miocene rocks of the lower Fars Formation in Abu Dhabi range in thickness from 150 m in Bu Hasa and 200 m in Liwa. The lower Fars Formation includes argillaceous rocks, silt and marl, with evaporite and carbonate intercalations (Hassan and Al Aidarous 1985). Imes et al. (1994) indicated that the lower Fars Formation acts as a confining in western UAE. The Quaternary sediments in Al Ain area were classified by Hunting (1979) into four sedimentary units, from base to top including: sand dunes, desert plain deposits, alluvial sediments and sabkhas. The sand-and-gravel sediments represent the most important aquifers in the UAE, and seismic sections were used for identification of shallow geologic structures influencing the groundwater movement in the western gravel aquifer (Woodword 1994).

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3  Geomorphology and Geology and Their Influence on Water Resources

Eocene

Pabdeh

Simsima Formation

Qahlah Formation

Aptian Berriasian

Bajocian to Plainsbachian

TRIASSIC

Aruma Group

Cenomainian Hettangian Upper Middle Lower

UPPER - MIDDLE PERMIAN

S

Ex

SEMAIL OPHIOLITE

M

Rn

M

S

Mauddud and Nahr Umr formations

M

S Ex Rn

Unit 4

HAWASINA GROUP

Unit 3 Unit2 Unit 1

Elphinstone Group

JURASSIC

Tithonian Bathonian

Wasia

Musandam Group

Albnian

Rus Al Jibal Group

CRETACEOUS

Paleocene Maastrichtian Coniacian

ALLOCHTHONOUS UNIT

Oligocene

RusDammam Asmari

TERTIARY

Miocene

Ghalila Formation Milaha Formation Ghail Formation

LEGEND Limestone Dolomite Anhydrite Salt Sandstone Shale

S Ex Rn V

Chert

Hagil Formation

Conglomerate

Bih Formation

Marl

C L M

Sedimentary Melange Exotic limestone Rann Formation Haybi volcanics Non- deposition Unconformity Thrust Fault Chert Sedimentary Rocks Metamorphic Rocks

Fig. 3.9  Stratigraphy of rock outcrops in the mountainous areas of the United Arab Emirates. (After Warrak 1987; Alsharhan 1989)

3.4  Stratigraphic Units of Surface Outcrops The distribution of surface outcrops of major stratigraphic units in eastern and northeastern UAE is shown in Fig. 3.9. These rocks are divided according the nature of their composition into two groups: The first is called the autochthonous rock units, which were deposited in the same place where they are now; the other rock group is called allochthonous rock units, which were transported from other places than where these rocks are now located. The stratigraphy, lithology and hydrogeological characteristics of these rock units are illustrated in Figs. 3.8 and 3.9.

3.5  Geologic Structures

103 Strait of Hormuz

56o

55o

Bukha Musandam Peninsula

26o

ARABIAN GULF

26o

OMAN

Al Jeer Ghalilah Rams Wadi Hagil

Ras Al Khaimah

Wadi Bih Wadi Milaha

Umm Al Quwain

Khatt Habhab

Sir Abu Nuáir

Diba

Idhn

Sharjah

Khor Fakkan

Masafi

Dhaid

Dubai

6 25o

2 3

Ajman

7

1

GULF OF OMAN

Shaam

Fujairah Kalba 25o

4

Qarn Nizwa

5 Masfut

UNITED ARAB EMIRATES

Hatta

OMAN Al Ain LEGEND 1. 2. 3. 4. 5. 6. 7.

Ru’us Al Jibal Massif Diba Zone Northern Semail ophiolite zone Southern Semail ophiolite zone Hatta Zone Jibal Al Ain – Al Fayah zone Salt plug island zone

6 24o 40 km 56o

Fig. 3.10  Map showing the major structural zones affecting groundwater resources in the Eastern Region of the United Arab Emirates. (After Alsharhan 1989)

104

3  Geomorphology and Geology and Their Influence on Water Resources 55o 30’

AL-AIN REGION

55o 45’

56o 00’

F1 F2a

OMAN

F4a F5a

F3b Jabal Mohayer

F6 24o 30’

F3a Qarn Saba

F4b

24o 30’

F2b Bida Bint Saud F2c

F5b

Al Ain

F7

UNITED ARAB EMIRATES

24o 00’

OMAN

Thrust fault Axial trace of anticline Axial trace of syncline paleochannel Trace of buried Paleochannel

15 km 55o 45’

56o 00’

Fig. 3.11  Map showing shallow geologic structures and traces of buried paleochannels in the Al Ain Area, Eastern Region of the UAE. (After Woodword 1994)

3.5  Geologic Structures

105

3.5  Geologic Structures Results of interpretation of seismic section, in addition to extensive field work during the past three decades, pointed out the presence of several structural elements illustrated in Fig. 3.10 and revealed the presence of a large number of buried alluvial channels moving from east to west under recent clastic deposits (Fig. 3.11). The UAE is a part of the Arabian Plate, which is bounded by the Arabian Gulf in the east and the Red Sea rift system in the west. The Oman Mountains were formed as a result of convergence of the Arabian Tectonic Plate in the southwest with the Euro–Asian plate in the northeast. The front of eastern mountain ranges includes some structural depression such as the Dibba zone. The Arabian Peninsula consists of a plateau of crystalline igneous and metamorphic rocks, covered with sedimentary sequence tilting gently towards the Arabian Gulf in the northeast. The geology of the UAE is divided into two main areas: the eastern mountain ranges in the UAE and the western desert. The eastern mountain ranges in the UAE were subjected to deformation during the Cretaceous period associated with intrusion of the Semail ophiolite complex from the northwest above the Arabian Plate. The rocks forming the Guwiza Formation were deposited at the front of the ophiolite complex (Alsharhan 1989). Geologic structures, both surface and subsurface, have a profound effect on groundwater occurrence, flow, recharge and quality. Their impacts can be traced tens of km to the east, west and southwest, where known structural zones act as conduits for recharge water to move quickly from high mountain peaks in Ru’us Al Jibal and the eastern mountain ranges in the UAE, recharging groundwater in the gravel plains surrounding the mountain ranges from the east and west.

3.5.1  Surface Geologic Structures Surface geologic structures in UAE include: Ru’us Al Jibal, the Dibba zone, northern ophiolite zone, southern ophiolite zone, the Wadi Ham line, the Hatta zone and the Al Fayah and Al Ain Mountains (Fig. 3.10). 3.5.1.1  Ru’us Al Jibal The Ru’us Al Jibal Massif is tectonically affected by faulting, folding and thrusting. The thrust faulting appears primarily in the western and northwestern parts of the mountain ranges. The trend of faults is mainly north–south; with a few exceptions at Jabal Hagab structure, where trends are west or northwest (Fig. 3.10). According to Hunting (1979), the Ru’us Al Jibal Massif forms a broad, blockfaulted region of north or north–northeast trending folds, which control the align-

106

3  Geomorphology and Geology and Their Influence on Water Resources

ment of the western margin of the massif. The folds are commonly asymmetrical, with more steeply dipping western limbs. Thrust faulting within these three rock groups (Musandam, Elphinstone and Ru’us Al Jibal) on similar trends to the folding is a feature of the western part of the mountains. Thrust planes are inclined eastwards and in some areas pass laterally into zones of small, tight, recumbent folds. In areas of the latter, minor westerly dipping thrusts have been locally observed. The most significant structural feature that resulted from the tectonic compression occurred in the Mid-Tertiary is the Hagab Thrust, which displaced westward approximately 3800  m of shelf sediments over a distance of 5  km (Glennie et al. 1974; Glennie and Crausaz 1990). Along the western margin of the massif, east of Ras Al Khaimah, the Ru’us Al Jibal and Elphinstone Groups have been thrust over rocks of the Mesozoic Hawasina Series, which is overlain by late Cretaceous sediments, and the Lakshaifa and Fukhairi Beds (Hunting 1979). The thrust plane is best exposed in the Hagil Window. A series of wave-cut platforms, commonly associated with beach deposits, have developed on the western margin of the Massif up to a height of approximately 300 m. These platforms are bounded by scarps formed by recent drainage channels. The higher terraces are more severely eroded, suggesting a period of steady upward movement during the Holocene era (Hunting 1979). In addition to the effect of the karstic nature of limestone rocks on an aquifer’s recharge, the structural setting of the area also affects its hydrogeology because most of the tributaries of Wadi Al Bih basin are located along faults, which may allow the surface water to percolate deep into the ground. The aquifer’s hydraulic parameters, such as hydraulic conductivity and specific yield, are also affected by the presence of fractures. 3.5.1.2  Dibba Zone The Dibba zone is one of the most important geologic structures in the eastern mountain ranges in the UAE. The hydrogeologic importance of this zone is related to its direct influence on groundwater recharge and quality. The zone extends from Dibba in the northeast for 30 km in the southwest direction. The average with of this tectonic window is 20 km, separating the Musandam massive carbonate succession in the northwest from the Semail ophiolite sequence in the southeast. The zone is dominated by a fault which cuts southwest through folded limestone and deep-sea argillaceous sediments, along with chert and volcanics belonging to the Hawasina Series. Thrust slices outliers and exotic blocks of limestone, ultrabasics and low-grade metasediments are also to be found. Some are associated with the Semail Series and others with the sediments that form the Ru’us Al Jabal Massif.

3.5  Geologic Structures

107

3.5.1.3  Northern Ophiolite Zone The northern ophiolite zone is located in the area between south Dibba and the Wadi Ham line, extending north towards Eden village (Fig. 3.10). The zone also includes the metamorphic rocks in the parallel faults constituting the Wadi Ham structural line and the metamorphic rocks in the area between the Wadi Ham line and Khor Fakkan. The origin of the tectonic window through which the metamorphic rocks southeast Masafi appears to be related to the fault lines forming the Wadi Ham line, in addition to the elevation and weathering in this area. There are some secondary faults near Wadi Ham, trending northwest to north–northwest. The zones of these faults are filled with granitic intrusions. Folded serpentinite rocks, in addition to granitic intrusions, are located northwest Bithna village parallel to the Wadi Ham line. 3.5.1.4  Southern Ophiolite Zone The southern ophiolite zone is an anticlinal fold extending south of Wadi Ham to Wadi Hatta in the south. It consists of gabbro, layered diabase and pillow lave, as complicated belts dipping south. A visible lateral movement of about 10  km is observed in copper mineralization sites, between gabbroic rocks, or basal ultramafic rocks on the side of Wadi Ham. The copper mineralization sites meet with each other on the southern side of Wadi Ham. On the northern side of Wadi Ham, there is also a copper-mineralization site southeast the village of Bathina. The rock positions in the Wadi Ham area reveal a lateral movement along the wadi. The vertical dislocation occurred during the formation of this wadi reveals the effect of transverse movement in the Wadi Ham area. 3.5.1.5  Hatta Zone The Wadi Hatta zone lies in the southern mountain region, north of Masfut. Extending WNW–ESE, the zone separates two areas of Semail ophiolite rocks and is similar in structure and lithology to the Dibba Zone. This zone is a disturbed tectonic window bounded from the north and south with the Semail ophiolitic rocks, where the area has been subjected to periods of folding and fracturing. 3.5.1.6  Wadi Ham Line The Wadi Ham line is a fault zone along Wadi Ham which extends NNW from the area west of Fujairah. This structural zone is divided into two areas of high ground composed of basic and ultrabasic rocks of Semail Suit. Siliceous metasediments underlie the Semail rocks and are exposed in places in the fault zone.

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3  Geomorphology and Geology and Their Influence on Water Resources

3.5.1.7  Al Fayah Mountains The Al Fayah upper Cretaceous mountains are the oldest rocks exposed in the mountain range of Jebal Al Faiyah; Buhays, Aqabah, Thaneis, Rumaylah, Mileiha and Mulaghah, which are all located south of Al Dhaid city. These mountains are anticlinal structures forming series of asymmetrical anticlines composed of sedimentary rocks belonging to the Tertiary and upper Cretaceous ages. The rock outcrops of the Al Fayah Mountains represent an irregular line trending north–northeast in the north and middle parts and north–south in the south. The straightness of rock outcrops in the extreme north is attributed to a lateral tectonic movement to the right, along the Dibba zone, in the direction of Al Fayah Mountain range. 3.5.1.8  Al Ain Mountains The upper Cretaceous are the oldest rocks exposed in the mountain range of Jabal Zarub, Jabal Malaqat and Jabal Mundassa, and in north of Al-Ain at Jebel Auha (Fig. 3.10). These mountains consist mainly of cherty brecciated limestone, lubricated with serpentinite and radiolarite. The most prominent geologic structure in the Al Ain area is Jabal Hafit, which is composed primarily of Tertiary carbonates (foraminiferal limestone, nummulitic limestone and conglomeratic or nodular limestone), marl and marly limestone with minor evaporites and dolomites (Hunting 1979; Warrak 1986). The structural setting of Jabal Hafit was described by Whittle and Alsharhan (1994): “Jabal Hafit is an anticlinal structure, plunging south in Oman and north in the UAE. This structure is approximately 29 km long, 5 km wide, and reaches an elevation of about 1160 m above mean sea level. At its northern end, the Hafit fold is symmetrical with flank dips about 10° and is cut by numerous normal and near-­ vertical faults and some reverse faults. Most of these faults either die out away from the core of Jabal Hafit or show reduced displacement. In the northern part of Jabal Hafit, overturning toward the east, is indicated as the middle and late Eocene carbonates dip about 10° and are overlain by Oligocene carbonates, which dip steeply or are overturned in the eastern limb of the structure, and dip gently in the western limb. In the central part of Jabal Hafit, there is a tightly-pinched, overturned syncline with a reverse fault in the overturned limb. The southern part is overturned at all exposed horizons, and is displaced toward the east, with the overturned limb being cut by a thrust.” The Middle Eocene Dammam limestone is an important aquifer in Jabal Hafit, where the rain falling on the mountain outcrops moves through numerous structural and karstic features to recharge groundwater in the Dammam aquifer and the surrounding sand-and-gravel aquifers. Field investigations by the authors indicated that the groundwater in Al Jaww plain on the eastern side of Jabal Hafit is distinctly different from the groundwater on its western side.

References

109 IRAN

N

BUNDUQ

DAS

SW FATEH SHARJAH MANDOUS SIR ABU RASHID DUBAI NUAIR

BELBAZEM UMM ZAKUM BU HASEER SATAH ZIRKU ALSALSAL JARNAN QARNAYN SAATH ARAZANAH AL RAAZ BOOT UMM GHASHA AL BATEEL AD DALKH UMM AL ANBAR DALMAH MUBARRAS UMM HAIR SIR HAIL AL LULU DALMA BANI YAS ZUBBAYA ABU DHABI JEBEL DHANNA

HAMR ANIYA H

UMM SHAIF NASR YASSER

AL KHAIR FALLAH FATEH

UNITED ARAB EMIRATES MARGHAM

DHAFRAH MUSHASH

S AUDI ARABI A

BU HASA HOWAILA

ARJAN

ASAB

SHAH

AL AIN

OMAN

SAHIL H SY AM NC RA LIN AQ RA E BN OS E

SYNCLINE GHURAB

RUWAIS

JARN YAPHOUR

BIDA HAMAMA ANTICLINE

SY NC LI NE

BIKH SALA

BU LABYAD BIDA BAB AL QEMZAN

FA LA HA

UMM ALUISHAN

R AN AS TI SA CL D IN R E

QATAR

MUBAREK ABU AL BAKHOOSH

GULF OF OMAN

SALEH

GULF

OM AN

ARABIAN

QUSAHWIRA

Oil and gas field Anticlinal structure Synclinal Structure Salt dome Thrust fault 40 km

Fig. 3.12  Map showing major subsurface geologic structures in the United Arab Emirates. (After Alsharhan 1989)

3.5.2  Subsurface Geologic Structures As sand dunes cover the Pre-Cenozoic rocks, the location of geologic structures is only discernible from geophysical surveys and data obtained from oil wells. Figure 3.12 shows the subsurface folds in the UAE and their directions. The UAE is located in the northeast Rub al Khali basin. The boundaries of this basin are controlled by dextral and sinistral wrench faults of various ages. Magnetic basement lineaments in conjunction with trends on gravity maps identify several left-lateral wrench faults, while interpretation of seismic lines position several flower structures at Hair Dalma, Ruwais, Jarn Yaphour and the Al-Ain areas.

References Al Amari KA (1997) Assessment of environmental impact of re-injecting oil-field water in the miocene clastic sediments on the shallow aquifer at Bu Hasa oil field, United Arab Emirates. Unpublished M. Sc. Thesis, UAE University, Al Ain

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Alsharhan AS (1985) Depositional environment, reservoir units, evolution and hydrocarbon habitat of Shuaiba formation, lower cretaceous, Abu Dhabi, UAE.  Am Assoc Petrol Geol Bull 69:899–912 Alsharhan AS (1989) Petroleum geology of United Arab Emirates. J Petrol Geol 12(5):253–288 Alsharhan AS (1994) Albian clastics in the wester Arabian Gulf region, a sedimentological and petroleum geological interpretation. J Petrol 17:279–300 Alsharhan AS, Kendall CGSC (1986) Precambrian to Jurassic rocks of the Arabian Gulf and adjacent areas, their facies, depositional setting and hydrocarbon habitat. Am Assoc Petrol Geol Bull 70:977–1002 Alsharhan AS, Nairn AEM (1986) A review of the cretaceous formations in the Arabian peninsula and the Gulf: part I. lower cretaceous (Thamama group) stratigraphy and Palaeogeography. J Pet Geol 9:365–391 Alsharhan AS, Nairn AEM (1988) A review of the Cretaceous formations in the Arabian Peninsula and Gulf, Part II. Mid Cretaceous (Wasia Group) stratigraphy and palaeogeography. J Pet Geol 11:89–112 Alsharhan AS, Nairn AEM (1995) Stratigraphy and sedimentology of the Permian in the Arabian basin and adjacent areas: a critical review. In: Scholle PA, Peryt TM, Ulmer-Scholle DS (eds) The Permian of Northern Pangea, vol 2. Springer Verlag, Berlin Heidelberg, pp 187–214 Alsharhan AS, Nairn AEM (1997) Sedimentary basins and petroleum geology of the Middle East. Elsevier, Amsterdam, pp 1–942 Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region: The Arabian Gulf and adjoining areas. Elsevier Publishing Company, New York, p 331 Azzam IN (1995) Sequence stratigraphy of Middle Cretaceous siliciclastic sandstone (Tuwayil Formation) in West Abu Dhabi: a model approach to oil exploration. In: Al-Husseini MI (ed) Middle East petroleum geosciences Geo’94, vol 1. Gulf Petro Link, Bahrain, pp 155–165 Embabi NS (1991) Dune types and patterns in United Arab Emirates using Landsat TM data. In: The 24th international symposium on remote sensing of environment, Rio de Janeiro, Brazil, p 13 Finzi V (1973) Late quaternary subsidence in the Musandam expedition, 1971–1972, scientific results: part I. Geograph J 139:414–421 GeoConsult (1985) Projects 21/81, drilling of deep water wells at various locations in the UAE, v. III, 1. Masfut, 2. Al Ain, 3. Al Wagan, 4. Medeisis, 5. United Arab Emirates, Ministry of Agriculture and Fisheries, Water and Soil Department, Unpublished Report on file at Ministry of Agriculture and Fisheries, Dubai, Liwa Ghoneim A (1991) Study regional geography – part I, physical geography of the UAE reading for all for publication and distribution, Dubai, UAE, p 242 (in Arabic) Glennie KW, Boeuf MGA, Hughe Clark MW, Moody-Stuart WFH, Piller WFH, Reinhardt PM (1974) Geology of the Oman mountains, parts I, II, III. Verh Kon Nederlands Geol Mijn Gen Transactions, Geol Survey 31:423 Glennie KW, Crausaz CU (1990) Geologic guidebook, northern Oman mountains. Society of Explorationists in the Emirates, ADCO (Abu Dhabi Company for Onshore Oil Operations), Abu Dhabi, p 38 Hassan AA, Al-Aidarous A (1985) Regional aquifer geology  – onshore Abu Dhabi Geology Department, ADCO project report 1584–50. Abu Dhabi Geology Department, Abu Dhabi, p 28 Hassan TH, Mudd GC, Twombley BN (1975) The stratigraphy and sedimentation of the Thammama group (lower cretaceous) of Abu Dhabi. In: 9th Arab Petroleum Congress, Dubai, United Arab Emirates, pp 1–11 Hunting (Hunting Geology and Geophysics Ltd) (1979) Report on a mineral survey of the UAE, 1977–1979, northern mountains program, v. 1—geological map of the UAE.  Ministry of Petroleum and Mineral Resources, Government of the UAE, Abu Dhabi, p 42 Hutchinson C (1996) Groundwater resources of Abu Dhabi Emirate. US Geological Survey Administrative Report, Abu Dhabi, p 136 Imes JL, Hutchinson CB, Signor DC, Tamayo JM, Mohamed FA, Hadley DG (1994) Ground-­ water resources of the Liwa Crescent area, Abu Dhabi Emirate. U.S.  Geological Survey

References

111

Administrative Report 94-001: U.S. Geological Survey-Abu Dhabi National Drilling Company, Abu Dhabi, p 138 Kendall CGSC, Alsharhan AS (2011) Holocene geomorphology and recent carbonate-evaporite sedimentation of the coastal region of Abu Dhabi, United Arab Emirates. In: Kendall CGSC, Alsharhan AS (eds) Quaternary carbonate and evaporite sedimentary facies and their ancient analogues, International Association of Sedimentologists special publication Nr, vol 43. Wiley, Oxford, pp 45–88 Murris RJ (1980) Middle East stratigraphic evolution and oil habitat. Am Assoc Pet Geol Bull 64:597–618 Patterson RJ, Kinsman DJJ (1981) Hydrologic of framework of a sabkha along Arabian gulf. AAPG Bull 65:1457–1475 Rizk ZS, Alsharhan AS (2003) Water resources in the United Arab Emirates. In: Alsharhan AS, Wood WW (eds) Water management perspectives. Evaluation, management and policy. Elsevier Science, Amsterdam, pp 245–264 Rizk ZS, Alsharhan AS, Shindo SS (1997) Evaluation of groundwater resources of United Arab Emirates. In: Proceedings of the third gulf water conference, Muscat, Sultanate of Oman, pp 95–122 Sanford WE, Wood WW (2001) Hydrology of the coastal sabkhas of Abu Dhabi, UAE. Hydrogeol J 9:358–366 UAE National Atlas (1993) United Arab Emirates University. GEO Projects, United Arab Emirates United Nations (1982) Groundwater in the eastern Mediterranean and western Asia: Department of Technical co-operation for development. Nat Resour, Water Series 9:195–206 Warrak M (1986) Structural evolution of the Northern Oman Mountain Front, Al-Ain Region. In: Symposium on the hydrocarbon potential of intense thrust zones, Ministry of Petroleum and Mineral Resources, UAE and OPEC, Abu-Dhabi, pp 375–431 Warrak M (1987) Synchronous deformation of newautochthonous sediments of the Northern Oman Mountains. In: 5th conference, S.P.E., Bahrain, pp 129–136 Whittle GL, Alsharhan AS (1994) Dolomitization and chertification of the early Eocene Rus formation in Abu Dhabi, United Arab Emirates. Sediment Geol 92:272–285 Whittle GL, Alsharhan AS (1995) Observations on the diagenesis of the lower triassic sudair formation, Abu Dhabi, UAE. Facies, Germany 32:85–194 Whittle GL, Alsharhan AS, El Deeb WMZ (1996) Facies analysis and early diagenesis of the Middle-Late Eocene Dammam Formation, Abou Dhabi, United Arab Emirates. Carbonates Evaporites 11(1):32–41 Wood WW, Sanford WE, Al Habshi AS (2002) Source of solute to the coastal sabkhas of Abu Dhabi. UAE Geol Soc Am 114(3):259–268 Wood WW, Sanford WE, Frappe SK (2005) Chemical openness and potential for misinterpretation of the solute environment of coastal sabkhat. Chem Geol 215(1–4):361–372 Woodword D (1994) Contribution of a shallow aquifer study by reprocessed seismic sections from petroleum exploration surveys, eastern Abu Dhabi, UAE. J Appl Geophys 31:271–289

Part III

Climate and Water Balance

The climate represents one of the key determinants of the hydrogeologic conditions prevailing in the Arabian Gulf region, including the UAE. The coincidence of rainfall scarcity with high natural evaporation is the main cause of the prevailing drought and absence of surface water resources. The scarcity of rain leads not only to the lack replenishment of aquifers but also causes depletion of these aquifers at record rates. The problem is futher complicated by excessive pumping of groundwater in order to meet the ever-increasing needs of a growing population and the unprecedented social and economic development in the country. Global warming and climate change increase the scarcity of water resources in an already dry area. Data collected by the national centers and authorities from stations within the country indicated rising temperatures at all monitored stations. Changes in temperature and rainfall pose additional pressure on the limited conventional water resources in the country. Global warming and climate change cause variations in temperature and rainfall, the decline of aquifer recharge, shortage in irrigation water, depletion of aquifers and increasing soil salinity. The climatic water balance illustrates the monthly relationship between rainfall and evapotranspiration and distinguishes water surplus areas from water deficit ones. In water surplus areas, part of rainwater can contribute to groundwater recharge, while water deficit areas suffer from severe drought because the monthly evapotranspiration rates greatly exceed monthly rainfall. Results of grain-size analysis and infiltration measurements are used to determine the hydraulic properties of gravel plains and sand dunes. The sudy indicated that the percentage of runoff from rainfall is 18% in northern Oman Mountains and 3% in Jabal Hafit area. The results of this study can help in defining potential areas for aquifer-storage recovery projects, which have already started in more than one emirate. The gravel plains and sand dunes are the most favorable aquifers for artificial groundwater recharge, especially where these aquifers are severely  depleted due to the over-exploitation of their groundwater reserves.

Chapter 4

Climate Conditions and Their Impact on Water Resources

Abstract  The mean annual temperature is 25 °C, with slightly cooler temperatures in the eastern mountains. The mean monthly relative humidity over UAE is around 60% during winter and around 50% during summer, varying between 46% in May to 64% in December. The two wind systems affecting the UAE are the winter “Shamal” winds, which affect the western coast, and the summer monsoon, which affects the Gulf of Oman and eastern mountain areas. The average annual evaporation is 3322 mm, while the mean annual rainfall is 100 mm for the period 1976–2015. The principal rains fall between November and March, with the maximum intensity during February and March, and about 90% of the precipitation falls during winter and spring. The wettest months are February and March, when 60% of precipitation is received. February is the rainiest month, with an average of 37.9 mm, while June is the driest month with an average of 0.3  mm. However, rainfall is extremely variable in space and time, depending on the climatic conditions, geographic location, local topography and rainfall driving mechanism. Global warming and climate change cause variations in temperature and rainfall, a decline of aquifer recharge, a shortage in irrigation water, a depletion of aquifers and increasing soil salinity. Data collected by the National Center of Meteorology and Seismology from stations based in airports around the country indicated a rise of 0.6–2.7 °C in temperature. Changes in temperature and rainfall pose additional pressure on the limited conventional water resources in the country. A detailed climate-change modeling study of Abu Dhabi Emirate indicates increasing water consumption in response to the increase of municipal and industrial uses. However, reductions in agricultural water use could maintain future water use equal to current consumption levels.

4.1  Introduction The UAE is an arid country with a long, hot summer and a short, mild winter. The summer season is dry, extends from April to November, and temperatures may reach 50 °C. The average air temperature during July is 35 °C, and the average rainfall is © Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_4

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4  Climate Conditions and Their Impact on Water Resources

2 mm. The winter is the most unstable period when active weather systems can produce rain and strong winds. The winter months are limited to the period December– March, during which the temperature is mild and rains are light to moderate. January is the coolest month, with an average temperature of 18 °C, while February is the rainiest month, with an average rainfall of 42 mm (Boer 1997). There are 132 rainfall recording stations in the UAE operating under the supervision of the Ministry of Climate Change and Environment, in addition to other stations working under the supervision of other government agencies, such as airports and universities. Precipitation in the UAE is erratic, and the major part of the annual rain falls during a few storms, with a total duration of a few hours. The average annual rainfall varies between 90 mm/year near the coast and about 160 mm/year in the mountain areas. Precipitation for the period 1983–1985 was very low, with annual amounts considerably less than half of the annual average of the period 1976–2003. Between 2000 and 2015, the annual rain was constantly less than the mean annual average. Tables 4.1a and 4.1b include a summary of the average minima, maxima and averages of climatic parameters including: temperature (°C), relative humidity (%), rainfall (mm), wind speed (km/hr) and evaporation rate (mm/d) for the main meteorological stations in the UAE for the period 1979–2015.

4.2  Solar Radiation The UAE is situated between latitudes 22° 40′ and 26° 00′ N spanning the Tropic of Cancer and, therefore, receives maximum solar radiation on June 21, when the sun appears directly overhead giving an angle of incidence of the sun rays of 90° 00′ (Al-Shamesi 1993). Conversely, on December 21, the incidence of the sun rays falls to 43° 06′ as the lowest insulation levels are received (Alsharhan et al. 2001; Rizk and Alsharhan 2008). Skies over the UAE tend to be relatively cloud free all year round, with the most extensive cloud cover in February and March, while the least cloud cover is experienced in June and November (Fig. 4.1). The number of daylight hours exceeds those of night from the March 21 to 21 September. In November, the ratio of sunshine hours to daylight peaks at 90%, and the minimum is 74% in March. A maximum of 13.6 h of daylight is attained on the June 21, falling to a minimum of 10.7 h on December 21. The average annual sunshine hours over the UAE is 10 per day (Hejase and Assi 2013), which corresponds to an average annual solar radiation of approximately 2285 kWh/m2 (Fig. 4.2; Table 4.2).

4.3  Air Temperature The maximum and mean air temperatures peak in July, reaching 41.8  °C and 35.1 °C, respectively, with extreme maximum temperatures of 50 °C in June and July at Asab station in central onshore Abu Dhabi Emirate (Figs. 4.3a and 4.3b).

Year 1976–1977 1977–1978 1978–1979 1979–1980 1980–1981 1981–1982 1982–1983 1983–1984 1984–1985 1985–1986 1986–1987 1987–1988 1988–1989 1989–1990 1990–1991 1991–1992 1992–1993 1993–1994 1994–1995 1995–1996 1996–1997 1997–1998 1998–1999

Temperature (°C) Min Max Mean 26.1 28.2 27.1 26.7 28.3 27.3 26.2 28.2 27.4 26.3 28.4 27.5 26.6 28.8 27.6 26.1 28.2 26.8 25.5 27.4 26.1 26.3 28.4 27.1 26.2 28.1 27.1 26.5 29.1 27.3 26.5 28.4 27.3 26.8 28.4 27.3 25.6 27.6 26.6 26.2 28.6 27.7 26.6 27.7 27.3 26.0 27.1 26.6 27.2 29.8 27.9 27.6 29.4 28.1 26.6 28.6 27.6 26.4 28.6 27.7 26.3 27.2 26.7 26.8 29.2 28.1 27.4 29.4 28.6

Relative Humidity (%) Min Max Mean – – – – – – – – – – – – – – – 19.5 19.5 19.5 37.5 56.8 52.0 42.5 60.8 51.2 39.0 55.4 49.0 47.6 65.4 55.8 48.5 57.6 53.2 50.1 67.7 56.6 37.5 59.5 51.1 52.5 62.8 57.6 50.5 65.4 56.4 28.6 54.1 46.3 50.9 67.3 55.9 44.3 70.5 53.8 36.7 71.9 54.5 42.2 60.8 54.5 41.8 63.7 53.8 40.6 67.6 52.9 43.1 61.3 52.3

Rainfall (mm) Min Max 99.7 263.1 46.4 209.2 29.6 111.8 5.40 184.3 22.0 136.3 183.1 428.0 104.9 480.0 1.20 110.4 3.00 57.80 11.0 92.40 10.7 292.8 4.30 306.0 46.7 135.4 50.6 291.0 5.60 114.8 34.1 195.2 4.50 213.4 1.00 139.4 62.3 266.6 52.7 548.2 79.6 318.0 31.8 347.0 14.6 109.2 Mean 104.3 46.80 29.60 50.70 53.70 209.3 131.2 3.60 12.50 38.40 122.1 190.5 63.10 131.0 38.90 113.6 104.3 33.80 105.2 223.1 161.0 139.3 39.00

Wind Speed (km/hr) Min Max Mean 2.2 6.6 4.9 3.1 10.5 5.6 2.9 9.7 5.5 2.7 7.3 4.9 2.2 8.7 5.4 2.1 7.7 5.1 2.0 8.4 5.2 1.9 9.8 5.3 1.7 8.9 5.1 1.8 9.6 5.4 1.9 9.5 5.6 1.7 9.8 5.9 1.4 8.8 5.2 1.5 8.9 5.6 1.4 9.7 5.7 1.7 9.7 5.3 1.7 9.3 5.2 1.6 9.2 5.5 1.1 9.4 5.2 1.9 8.7 5.1 1.5 9.5 4.8 1.7 9.2 5.1 2.1 8.2 5.2

Evaporation (mm/day) Min Max Mean 8.5 11.8 10.4 8.8 14.2 11.0 8.2 12.4 11.2 8.6 13.4 11.1 8.2 12.9 10.6 6.2 9.30 8.30 4.7 9.10 7.50 6.8 9.30 8.20 5.7 9.50 7.90 7.5 9.60 8.60 7.7 12.6 9.20 7.3 9.00 8.40 4.6 8.80 7.50 7.4 9.70 8.20 6.5 9.70 8.10 7.2 8.70 7.70 6.7 9.80 7.80 7.1 16.7 10.1 7.1 12.6 8.70 6.8 12.2 8.30 6.6 13.3 8.20 6.3 14.3 8.40 7.1 14.4 8.80 (continued)

Table 4.1a  Summary of average minima, maxima and mean annual air temperature (°C), relative humidity (%), rainfall (mm), wind speed (km/hr) and evaporation (mm/d) in some meteorological stations in the UAE for the period 1976–2003

4.3 Air Temperature 117

Year 1999–2000 2000–2001 2001–2002 2002–2003 Mean maximum Mean Mean minimum

Temperature (°C) Min Max Mean 26.8 28.9 27.9 26.6 28.6 27.8 20.7 28.8 26.0 23.1 29.2 26.7 20.7 27.1 26.0 26.1 28.5 27.3 20.7 27.1 26.0

Table 4.1a (continued) Relative Humidity (%) Min Max Mean 39.3 57.1 47.8 40.8 58.9 51.4 40.0 60.4 51.6 28.6 62.3 46.6 19.5 19.5 19.5 41.0 60.3 51.1 19.54 19.54 19.54

Rainfall (mm) Min Max 0.20 20.00 5.70 121.8 0.00 88.80 0.60 116.5 0.00 20.0 33.8 211.0 0.00 20.00 Mean 11.60 16.70 6.00 12.20 3.60 81.2 3.58

Wind Speed (km/hr) Min Max Mean 0.2 9.1 5.1 0.2 6.5 4.4 0.2 6.5 4.5 0.2 6.4 4.3 3.1 10.5 5.9 1.7 8.7 5.2 0.2 6.4 4.3

Evaporation (mm/day) Min Max Mean 7.0 13.8 8.80 – – – – – – – – – 4.6 8.70 7.50 7.0 11.6 8.90 4.58 8.65 7.47

118 4  Climate Conditions and Their Impact on Water Resources

Station Al Gheweifat Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Owtaid Mezaira Madinat Zayed AbuAl Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul Rezeen Abu Dhabi Airport Al Quaa Al Khazna Al Arad Damsa Sweihan

Solar Radiation (wh/m2) 5499.7 5679.8 5452.9 5031.9 5715.7 4576.0 5673.8 6010.6 5598.8 5948.9 5732.6 5865.1 5721.9 5395.4 6005.2 5981.3 6044.3 5909.3 6129.6 6032.8 5991.3 5816.9 5847.5

Rainfall (mm) 42.1 30.1 48.9 35.2 23.2 49.3 24.6 65.6 21.6 34.6 26.8 48.0 50.1 33.4 28.8 38.2 51.1 – 61.8 69.9 61.9 21.9 61.6

Temperature (°C) M. Max Mean 22.4 13.2 32.2 27.8 31.7 27.7 31.7 27.5 30.7 26.9 29.2 27.3 36.7 28.4 36.3 28.6 36.4 28.7 35.7 27.7 33.5 27.2 37.1 28.7 31.8 28.4 30.8 27.4 36.2 28.4 37.3 30.0 36.3 27.8 34.4 27.6 36.7 29.3 35.7 27.6 36.1 28.6 36.2 27.5 36.8 28.4 M. Min 26.4 25.2 24.7 24.5 22.9 25.9 20.4 21.9 22.4 21.2 21.6 20.0 25.8 24.5 21.1 22.5 19.9 21.4 21.5 20.9 21.9 18.7 21.2

Relative Humidity (%) M. Max Mean M. Min 31.3 20.5 36.4 86.3 69.9 49.5 85.8 66.3 42.0 79.0 55.8 33.3 87.1 69.3 45.8 84.5 73.3 57.5 82.2 42.8 18.0 83.0 45.2 18.1 80.7 45.8 19.7 86.6 56.3 27.5 85.7 62.8 33.9 77.2 41.1 16.8 78.4 62.6 42.6 84.8 69.3 49.7 79.7 48.9 22.9 68.3 35.9 16.8 79.8 44.2 16.8 81.6 58.8 31.7 75.8 43.4 21.0 82.6 50.2 22.9 75.3 42.8 19.5 83.9 45.2 18.3 79.8 48.9 21.0

Wind Speed (km/h) M. Max Mean 38.2 38.4 27.7 15.8 27.6 15.3 27.3 16.7 31.8 18.4 30.3 17.4 33.0 15.8 25.8 11.3 22.5 10.8 29.3 12.2 29.8 16.2 25.7 10.8 24.3 13.8 24.7 13.8 30.8 14.3 21.8 10.2 25.3 10.8 13.1 6.80 21.3 9.30 18.3 8.30 24.8 10.6 23.9 9.30 24.4 9.30 (continued)

Table 4.1b  Summary of average minima, maxima and mean annual air temperature (°C), relative humidity (%), rainfall (mm), wind speed (km/h) and evaporation (mm/day) in major meteorological stations in the UAE for the period 2003–2015

4.3 Air Temperature 119

Station Saih Al Salem Al Ain Airport Al Faqa Dubai Airport Sharjah Airport Um Al Quwain Al Malaiha Hatta Fujairah Airport Masafi Mebreh Mountain Ras Al Khaimah Airport Jais Mountain Mean maximum Mean Mean minimum

Table 4.1b (continued)

Rainfall (mm) 28.4 – 87.6 – – 29.9 53.7 57.6 – 105.4 32.2 –

84.9 105.4 48.8 21.6

Solar Radiation (wh/m2) 5524.8 6199.6 6146.1 5357.9 – 5350.5 5539.4 5335.3 – 5815.2 5611.4 –

5764.8 6199.6 5720.8 4576.0

21.7 37.3 33.6 21.7

18.9 30.0 27.2 13.2

Temperature (°C) M. Max Mean 36.3 27.6 36.3 28.8 35.8 27.9 33.6 27.8 34.5 27.0 33.6 27.1 35.6 28.1 34.0 27.8 32.6 28.5 31.7 26.7 23.7 20.8 35.3 27.7 16.5 26.4 22.0 16.5

M. Min 20.5 22.0 20.9 22.5 20.3 21.6 20.5 22.1 24.9 22.1 18.4 20.5 66.9 87.1 78.3 31.3

38.8 73.3 52.5 20.5

20.6 57.5 29.8 16.8

Relative Humidity (%) M. Max Mean M. Min 81.2 51.2 19.8 70.0 44.6 22.9 80.6 52.0 24.5 78.8 58.8 35.5 83.4 60.1 34.0 83.9 65.0 39.8 76.5 47.5 21.1 74.3 51.6 28.5 77.5 60.7 42.6 70.2 43.5 23.0 65.2 36.8 18.3 81.0 58.5 34.4 24.1 38.2 24.5 11.1

11.8 38.4 12.9 4.30

Wind Speed (km/h) M. Max Mean 28.8 11.9 13.9 7.20 21.8 9.10 12.4 6.60 11.5 5.80 25.3 11.6 26.1 9.60 26.4 12.7 11.4 5.80 20.3 8.80 32.4 18.2 11.1 4.30

120 4  Climate Conditions and Their Impact on Water Resources

4.3 Air Temperature

121 56

55

54

Arabian

QA TA

Abu Al Bukhoosh

R Qatnen

Zakum

Zirku Aazanah

Abu Dhabi

Dalma Island Ras Musherib

24

Yasat Al Hamra As Sila

Sir Bani Yas Jebel Dhanna

Al Al Bbyd Tarif

Owtaid

Al Jazeera B.G.

S A U D I A R A B I A

Madinat Zayed

Mukhariz

Razeen

Al Arad

Bu Hamra

Asab

Liwa

O M A N

Al Quaa

Medesis Hamim

53

54

N

Qasyoura Um Azimul

52

24

Al Wagan

UNITED ARAB EMIRATES Mezaira

23

25

Kalba

Rowda

Bu Hasa

Radoum

Masfut

Raknan Al Dhafra Al Ain Al Ain I.A. Al-Ain Qattara Al Khazna Khatam Al Shaklah Al Aryam Damsa Mezyad Al Wathbah Jabal Hafit

Al Qlaa

Bu Hasa

Dibba

Al Hibab Al Malaiha Jabal Ali Saih Al Salem Al Shiweb Ras Ganada Al Hayer Al Faqa Abu Dhabi I.A. Sweihan Forah

Das Island

Bunduq

Sham Buryrat

Ras Al Khaimah

Umm Al Quwain Tawiyen Dhudna South West Fateh Al Manama Ajman Falaj Al Mualla Masafi Sharjah Sharjah I.A. Al Dhaid Fujairah Sir Bu Nair Dubai Dubai I.A. Fujairah I.A.

25

Makassi

Gulf

AN OM

Symbol Period of Records 1974 - 2003 2003 - 2015 1974 - 2015

Gulf of Oman

53

52

LEGEND

55

23

50 km

56

Fig. 4.1  Locations of the main meteorological stations in the United Arab Emirates

Fig. 4.2  Mean minimum, mean and mean maximum annual solar radiation (kWh/m2) for the period 2003–2015

Station Al Gheweifat Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Mukhariz Owtaid Mezaira Madinat Zayed Abu Al Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul Rezeen Abu Dhabi Airport Al Quaa Al Khazna Al Arad Damsa Sweihan Saih Al Salim

January 4055 4058 4142 3796 4317 3392 4376 4558 4641 4030 4413 4319 4524 4263 4098 4567 4577 4499 4106 4551 4403 4476 4577 4339 3936

February 5008 5021 5059 4694 5188 4386 5240 5525 5601 5026 5338 5290 5496 5134 5045 5486 5536 5402 4987 5528 5347 5402 5494 5211 4805

March 5575 5731 5612 5396 6024 5090 5811 6221 6322 5908 6149 5983 6282 5945 5697 6275 6171 6277 5800 6392 6213 6241 6208 6079 5736

April 6051 6224 5957 5857 6456 5517 6161 6609 6610 6282 6574 6423 6574 6537 6225 6625 6788 6704 6737 6909 6830 6733 6434 6603 6192

May 6629 6866 6577 6403 6748 5912 6581 7223 6973 6790 7130 6988 6917 7002 6842 7117 7208 7307 7522 7481 7437 7201 6768 7142 6415

June 6593 6943 6738 6180 6784 5710 6728 7315 6801 6685 7285 6999 6692 6798 6616 7099 7074 7271 7589 7337 7345 7123 6230 7059 6774

July 6216 6668 6291 5633 6311 5010 6507 7004 6624 6356 6842 6322 6327 6495 6010 6614 6588 6775 7068 6813 6823 6672 6133 6587 6413

August 6342 6508 6167 5469 6282 4779 6222 6890 6734 6415 6637 6064 6372 6447 5820 6650 6588 6754 6727 6924 6732 6688 6441 6454 6151

September 5983 6108 5697 5046 6203 4672 6077 6734 6457 6180 6385 6061 6273 6049 5489 6456 6358 6549 6346 6634 6492 6471 6328 6273 6152

Table 4.2  Mean minimum, mean and mean maximum annual solar radiation (kWh/m2) for the period 2003–2015 October 5320 5558 5051 4570 5565 4055 5510 6013 5968 5424 5708 5679 5769 5429 4876 5863 5724 5813 5522 5817 5786 5777 5852 5583 5455

November 4349 4501 4186 3808 4617 3334 4673 5018 4948 4274 4705 4524 4826 4460 4203 4906 4815 4851 4578 4822 4755 4807 4869 4666 4385

December 3875 3971 3958 3531 4093 3055 4199 4429 4448 3815 4221 4139 4329 4104 3824 4404 4348 4330 3930 4347 4231 4304 4469 4174 3884

122 4  Climate Conditions and Their Impact on Water Resources

Al Ain Airport Al Faqa Dubai Airport Umm Al Quwain Al Malaiha Hatta Masafi Mobreh Mountain Jais Mountain Mean maximum Mean Mean minimum

4397 4608 3789 3859 3910 3718 4094 3590 3758 4608 4198 3392

5284 5517 4610 4861 4733 4552 5017 4507 4753 5536 5120 4386

6051 6359 5425 5731 5643 5502 6037 5678 5846 6392 5924 5090

7022 6838 6143 6306 6339 6341 6768 6537 6717 7022 6460 5517

7731 7330 6714 6355 6839 6523 6932 7205 7405 7731 6947 5912

7722 7216 6690 6019 6746 6789 7195 7230 7356 7722 6904 5710

7243 6794 6226 5735 6388 6232 6758 6837 6839 7243 6475 5010

7120 6770 6031 6039 6334 5977 6540 6580 6708 7120 6393 4779

6770 6667 5736 5948 6059 5684 6160 6203 6230 6770 6145 4672

5935 6024 5028 5242 5341 5030 5608 5316 5396 6024 5488 4055

4848 5066 4154 4354 4366 4115 4662 4190 4368 5066 4530 3334

4272 4564 3749 3757 3775 3561 4011 3464 3801 4564 4040 3055

4.3 Air Temperature 123

124

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.3a  Mean minimum, mean and mean maximum monthly air temperature (°C) for the period 1976–2003

Fig. 4.3b  Mean minimum, mean and mean maximum monthly air temperature (°C) for the period 2003–2015

The hottest month is July, and the monthly average temperatures are over 40 °C from May to September. The extremely hot conditions are experienced along the Arabian Gulf coast. The extreme minimum temperature (0.6 °C) was recorded in February at Al Ain (1991). The mean minimum and overall mean temperatures are lowest in January, reaching 12.4 °C and 18.3 °C, respectively. The monthly average temperatures are 25 °C between November and March, and January is the coldest month. Temperatures rise steeply from March to June and fall rapidly between October and December. The mean annual temperatures are approximately uniform throughout the country, with little local variations, mostly experienced in the eastern mountainous region, where the mean temperatures are around 25 °C. The interior UAE is cooler in winter and hotter in summer. Tables 4.3a and 4.3b show the mean maximum, mean minimum and mean average temperatures in the main meteorological stations in the UAE during the period 1976–2015.

Station Al Hibab Al Oha Barairat Dhaid Dibba Digdaga Falaj Almualla Hamraniyah Masafi Masfut Meleiha U.A.Q Mean maximum Mean Mean minimum

33.4 28.3 28.8 30.0 27.6 33.4

16.9 17.3 16.3 15.2 19.9 20.8

March Max Min 29.8 15.5 30.1 14.9 31.7 20.2 29.8 16.5 30.4 20.8 30.6 14.9 31.1 15.3 38.9 34.5 34.6 35.9 32.5 39.0

April Max 35.5 36.6 39.0 36.4 36.2 36.1 37.8 19.3 22.3 19.8 18.3 23.5 25.6

Min 18.2 18.7 25.6 18.8 24.7 17.7 18.4 45.2 40.1 40.2 42.8 36.8 45.2

May Max 40.8 42.2 40.4 41.6 41.5 41.4 43.6 24.9 27.0 25.3 23.1 26.9 29.8

Min 21.8 21.5 29.8 23.3 29.4 21.6 23.1 47.0 42.9 42.4 45.7 38.5 48.0

June Max 41.6 44.8 48.0 44.0 43.6 43.7 46.4 27.2 29.8 27.3 25.8 29.4 34.0

Min 23.5 24.8 34.0 26.4 32.1 24.5 26.0

25.2 13.1 26.7 14.5 30.1 17.0 36.2 20.4 41.4 24.8 44.1 27.6 22.7 10.2 24.4 11.7 27.6 14.9 32.5 17.7 36.8 21.5 38.5 23.5

14.1 14.6 13.9 13.0 19.4 19.4

29.2 24.4 24.9 27.0 25.9 29.2

27.6 22.7 23.2 25.7 25.0 27.6

13.0 13.7 12.7 12.0 16.7 16.7

February Max Min 26.4 12.7 26.6 12.5 28.2 17.5 27.1 13.8 27.8 18.0 26.8 11.7 26.6 12.8

January Max Min 24.9 11.3 24.4 10.2 26.9 16.4 24.7 12.4 26.9 16.6 25.9 10.7 24.8 11.2 31.5 30.4 29.0 28.5 32.5 34.8

Min 27.5 28.1 34.8 29.1 31.6 28.2 29.8 47.7 40.7 40.1 45.2 38.6 47.7

30.9 29.5 28.1 28.5 30.8 34.7

August Max Min 44.1 27.8 44.9 28.4 45.6 34.7 43.9 29.6 40.5 31.9 43.8 27.8 44.9 28.4 45.2 39.2 38.7 41.7 36.6 45.2

37.5 35.7 35.5 38.9 35.9 40.0

20.0 24.0 21.2 21.9 26.5 27.1

October Max Min 37.4 20.0 37.7 20.0 40.0 27.1 37.5 21.5 37.4 26.2 38.3 19.4 37.7 20.5

34.6 29.7 29.8 32.9 31.5 34.6

30.1 25.0 25.4 27.9 27.5 30.1

14.0 15.7 14.4 13.5 19.0 19.0

December Max Min 26.8 13.0 27.0 12.2 29.5 18.4 27.2 13.8 29.0 18.4 28.0 12.1 26.1 12.3

18.0 27.5 14.7 14.2 25.0 12.1

17.4 19.2 16.4 16.7 22.3 22.5

November Max Min 31.6 15.8 31.7 15.8 34.5 22.2 31.4 17.7 33.5 22.5 31.8 14.2 32.2 15.5

26.3 37.5 22.4 32.1 23.9 35.5 19.4 29.7

27.3 27.2 25.2 24.2 28.3 31.3

September Max Min 41.7 24.5 41.9 24.9 43.5 31.3 41.2 25.9 37.7 28.3 41.9 23.9 43.0 24.8

44.0 30.1 43.3 29.7 41.0 38.2 27.5 38.6 27.8 36.6

47.7 42.0 41.1 45.9 38.2 47.7

July Max 44.2 45.2 46.2 43.6 42.9 44.4 47.1

Table 4.3a  Mean maxima and mean minima of air temperatures (°C) at various meteorological stations in the UAE for the period 1976–2003

Station Al Gheweifat Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Mukhariz Owtaid Mezaira Madinat Zayed Abu Al Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul Rezeen Abu Dhabi Airport Al Quaa Al Khazna

June Max 42.8 39.1 38.0 30.3 36.0 33.2 Min 27.4 30.3 29.3 29.4 27.8 29.4

July Max 43.6 40.0 39.5 31.8 37.5 34.9 Min 29.4 31.8 31.1 31.0 29.5 31.2

August Max Min 43.2 29.3 40.0 32.5 39.5 31.6 32.5 31.4 38.1 30.0 36.0 32.1

September Max Min 40.3 26.4 38.6 31.1 37.3 30.3 31.1 30.1 35.9 27.8 35.0 31.3

October Max Min 36.2 22.8 35.2 28.4 34.0 27.6 28.4 27.3 32.9 24.5 32.7 29.5

18.2 13.6 14.8 12.4 14.4

13.9 14.0 14.6 13.6 14.5 11.9 18.7

25.8 31.8 33.4 31.9 29.4

32.7 32.0 32.4 31.2 28.9 33.0 27.2

19.8 16.4 17.6 15.1 16.8

17.2 17.4 17.8 16.5 16.8 14.9 20.9 29.7 37.0 38.7 37.0 34.4

37.8 37.1 37.5 36.2 33.8 38.2 31.5 22.8 21.0 22.6 19.4 20.2

22.4 22.1 22.3 20.8 20.6 19.9 24.7 34.3 42.2 43.7 42.2 39.4

42.9 42.4 42.7 41.6 38.7 43.4 35.7 26.6 25.0 26.9 23.2 23.9

26.6 26.4 27.0 25.1 24.1 23.8 28.5 35.5 44.3 45.8 44.4 40.8

45.2 44.4 44.5 43.4 39.1 45.7 36.6 28.3 26.4 28.7 25.3 26.1

27.7 27.6 28.5 26.7 26.1 26.1 30.4 36.8 45.1 46.3 45.1 42.3

46.0 45.5 45.2 44.7 40.9 46.3 38.7 30.1 29.1 30.6 28.4 28.8

30.4 29.8 30.3 29.1 28.5 29.1 32.3 37.4 45.0 45.3 45.1 42.8

45.9 45.6 45.1 45.0 42.0 45.8 40.2 30.9 29.9 30.1 29.3 29.6

30.8 30.2 30.4 29.5 29.4 29.9 32.9

36.0 42.2 42.9 42.3 40.5

42.6 42.4 42.1 41.9 38.9 42.9 37.2

25.0 11.5 28.3 13.8 32.7 16.7 37.7 21.4 42.7 25.5 45.0 27.7 45.4 30.1 44.8 30.4 42.3 23.9 12.0 27.0 13.9 31.2 16.2 36.5 20.5 41.7 24.3 43.8 25.8 44.5 28.7 44.3 29.4 41.5

23.4 27.6 29.2 27.5 26.0

28.2 27.7 27.9 26.9 25.6 28.4 24.4

33.8 37.8 38.6 37.9 36.4

27.2 22.4 23.3 21.2 22.9

22.7 23.1 23.6 22.6 23.4 21.0 28.0

29.4 31.4 32.2 31.5 30.9

31.5 31.3 31.4 30.9 30.2 31.9 29.6

27.3 38.0 22.7 31.8 26.1 37.1 22.5 30.9

29.2 26.3 27.3 25.6 26.7

37.9 37.7 37.6 37.4 35.4 38.3 33.9

December Max Min 24.0 13.1 24.1 18.5 23.4 18.9 18.5 18.6 23.2 16.9 23.6 21.3

24.8 26.0 26.7 26.0 26.2

25.7 25.6 26.1 25.4 24.9 26.5 24.5

19.8 13.4 15.3 12.3 15.0

13.1 13.7 14.8 13.7 15.6 11.7 20.0

18.1 26.7 13.3 18.3 25.7 13.6

23.7 18.1 19.9 16.6 18.8

18.5 18.9 19.6 18.6 19.9 16.4 24.3

17.3 25.4 11.8

November Max Min 29.8 18.7 29.8 24.0 28.9 23.8 24.0 23.4 28.3 21.2 28.6 26.0

17.7 11.8 13.1 10.5 13.0

Min 25.5 28.1 27.2 27.7 26.2 27.7

22.5 24.3 25.2 24.2 24.2

May Max 40.5 36.3 36.6 28.1 34.9 31.8

26.9 26.8 27.1 26.2 26.7 25.8 31.0

Min 21.2 23.5 23.2 23.3 22.2 23.5

11.8 12.3 13.1 11.9 13.3 9.80 17.7

April Max 34.8 31.1 31.5 23.5 30.5 27.5

24.4 24.2 24.7 23.9 23.3 24.8 22.5

March Max Min 29.7 16.4 27.0 19.9 26.8 19.5 19.9 19.3 26.3 18.4 23.7 20.4 25.7 38.2 21.3 31.6

February Max Min 25.5 13.1 23.2 17.2 23.1 17.1 17.2 16.8 23.1 15.8 21.8 19.0

24.2 10.2 27.7 12.1 32.2 15.8 37.6 20.8 42.9 24.9 44.9 26.1 46.0 28.8 46.2 29.5 42.9

January Max Min 22.5 11.2 21.7 16.5 21.4 16.6 16.5 16.0 21.3 14.3 21.2 18.8

Table 4.3b  Mean maxima and mean minima of air temperatures (°C) at various meteorological stations in the UAE for the period 2003–2015

Al Arad Damsa Sweihan Saih Al Salim Al Ain Airport Al Faqa Dubai Airport Sharjah Airport Umm Al Quwain Al Malaiha Hatta Fujairah Airport Masafi Mobreh Mountain Ras Al Khaimah Jais Mountain Mean maximum Mean Mean minimum

29.2 24.0 27.1 25.9 27.8 26.8 27.5 25.6 26.8

44.8 45.3 45.6 44.9 44.9 44.9 41.2 42.6 41.3

31.9 28.3 30.1 28.9 29.9 29.6 30.2 28.4 29.6

44.4 44.6 45.5 44.9 44.6 44.5 41.4 42.5 41.3

31.6 29.0 30.6 29.1 30.4 29.8 30.5 28.4 29.4

41.8 42.1 42.9 42.3 42.0 41.9 39.1 40.2 38.8

28.3 24.6 26.7 25.5 27.4 26.1 27.7 25.2 26.3

37.5 37.8 38.6 38.1 37.8 37.4 35.6 36.6 35.5

23.3 19.9 22.3 21.6 23.6 22.0 24.3 21.6 23.0

31.3 31.4 32.2 32 31.5 31.0 30.7 31.2 30.3

26.2 26.5 26.8 26.8 26.8 25.7 26.3 26.5 25.8

12.5 9.9 12.9 13.3 14.7 13.1 16.3 14.0 15.1

27.0 35.6 23.3 29.8 22.1 23.1 17.9 17.0

19.0 22.6 14.8 14.3 14.5 9.90

17.6 26.1 13.4 18.7 25.2 14.6 22.5 26.7 18.9

17.5 15.0 17.7 17.4 18.8 17.6 20.0 17.4 19.0

19.1 24.8 14.6 12.0 13.1 8.00

44.2 44.0 44.9 43.9 44.6 44.2 39.7 41.4 39.7

22.9 12.7 25.4 14.3 29.2 17.0 34.1 21.2 39.1 25.3 41.0 27.4 41.9 29.6 41.8 29.8 39.4 10.9 6.10 13.1 8.10 17.4 12.2 21.6 16.6 26.8 21.4 29.9 24.0 30.4 25.0 29.6 24.4 27.3

26.4 21.5 24.7 23.7 25.5 24.4 24.9 22.9 24.5

12.0 13.1 8.00 26.0 27.2 21.3

41.9 42.1 42.7 41.8 42.3 41.7 37.8 39.3 38.1

10.9 6.10 13.1 8.10 17.4 12.2 21.6 16.6 26.8 21.4 29.9 24.5 30.4 25 29.6 24.4 27.3 22.1 23.1 17.9 17.0 25.2 18.8 29.2 19.0 33.4 20.9 38.7 24.7 43.7 29.1 45.8 31.2 46.3 32.3 46.2 32.9 42.9 31.3 38.6 29.5 32.2

22.2 18.1 20.7 19.8 21.4 20.3 21.2 19.0 21.0

17.0 27.2 13.6

36.9 36.8 37.4 36.7 37.0 36.4 33.2 34.5 33.9

25.5 37.2 21.3 31.9

16.2 13.8 16.2 15.8 17.1 16.2 17.7 15.8 16.7

25.0 11.9 26.6 13.3 30.1 15.9 35.6 19.3 40.6 23.4 42.6 26.2 43.1 29.2 42.5 29.1 40.7

31.9 31.9 32.3 31.7 31.5 31.3 28.6 29.3 28.9

26.9 33.5 23.7 27.4 24.2 25.2 20.2 19.0

12.4 11.0 13.7 13.4 14.4 13.5 15.5 13.4 14.6

20.7 12.9 23.3 14.7 27.7 17.7 32.7 22.4 37.8 27.0 39.8 28.9 39.3 29.2 38.4 28.5 37.3 12.5 7.90 15.1 10.0 19.3 13.8 24.0 18.2 29.2 23.2 31.8 25.9 32.5 26.7 31.8 26.1 29.6

27.6 27.4 27.9 27.6 27.7 27.0 25.6 26.0 26.0 25.3 37.3 21.7 31 26.6 35.7 23.0 29.9 29.0 34.2 26.4 30.3

11.3 9.0 11.2 11.6 12.6 11.5 14.4 12.3 13.5

24.3 11.4 27.1 13.4 31.5 15.8 36.2 20.0 41.3 23.6 43.5 25.9 44.2 28.7 43.7 28.7 41.4 23.4 12.8 26.1 14.7 30.5 17.6 35.6 22.2 40.7 27.0 42.1 29.2 40.4 29.8 39.2 28.6 38.7 24.6 16.9 25.8 18.0 28.6 20.3 33.7 24.7 38.4 29.1 39.2 31.2 37.5 31.5 36.1 30.5 35.7

24.4 24.4 24.6 24.7 24.7 23.7 24.2 24.4 23.8

128

4  Climate Conditions and Their Impact on Water Resources

4.4  Relative Humidity Relative humidity is usually expressed as a percentage of the saturation moisture content for a given temperature and pressure. The humidity is high in coastal areas, decreasing sharply towards the interior. The mean relative humidity decreases fromsssmore than 60% in Abu Dhabi to 45% in Al Ain to 25% at the Liwa, which marks the northeastern corner of Rub al Khali desert. The mean maximum humidity varies from 76% during May to 89% during December, January and March, while the mean minimum humidity varies from 17% during May to 37% during December (Figs. 4.4a and 4.4b). During winter months, the mean relative humidity varies from 46% in May to 64% in December. During winter months, the mean relative humidity increases by about 10–15% from the interior to the coastal regions, while during the summer months this variation is 20–25%. In general, the mean monthly relative humidity over UAE is around 60% during winter and around 50% during summer. The diurnal variation in relative humidity is of extreme nature, varying between 2% at the end of the day and 100% in early morning. The maximum relative humidity is reached during the November–March period, while the minimum relative humidity is during May. Tables 4.4a and 4.4b show the mean maximum, mean and mean minimum relative humidity (%), at the main meteorological stations for the period 1976–2015.

Fig. 4.4a  Mean minimum, mean and mean maximum monthly relative humidity (%) for the period 1976–2003

4.5 Wind Speed

129

Fig. 4.4b  Mean minimum, mean and mean maximum monthly relative humidity (%) for the period 2003–2015

4.5  Wind Speed There are two wind systems affecting the climate of the UAE: the winter “Shamal” (north) winds and the summer monsoon. The winter depressions, which descend the Arabian Gulf from the north and northwest, give rise to the cold, northwesterly “Shamal” air flow. The “Shamal” winds blow all year, but their speeds increase during the period between March and April to hit a top speed of about 41 km/hr (Al Shamesi 1993; Alsharhan et  al. 2001). The “Shamal” winds affect the western coastal region in Ras Al Khaimah, Umm Al Quwain Ajman Sharjah, Dubai and Abu Dhabi. The wind speed changes from light to mild with an increasing tendency during summer. The second wind system is the summer monsoonal low, which develops over Rub al Khali desert. During the fall season, the wind speed generally decreases inland. The strongest winds affect the eastern coastal area along the Gulf of Oman, eastern mountain ranges and the western coastal area along Arabian Gulf. The inland desert plains are characterized by the lowest wind speeds. The mean maximum wind speeds are 8.9  km/hr in February and March and 8.7 km/hr in June, and the minimum wind speed is 6.5 km/hr in November (Figs. 4.5a and 4.5b). The winter months of December, January, February and March, together with October and November, have lower wind movement in comparison with the summer months. Wind becomes stronger between March and August, coming predominantly from the northwest in Abu Dhabi, west in Dubai and Sharjah and north in Ras Al Khaimah. Maximum gusts of 68.5 km/hr (Abu Dhabi), rising to as much as 130 km/hr (Sharjah), have been measured. The strongest winds are felt along the eastern coast, followed by the mountainous region, whereas the lightest winds are

Month Al Hibab Aloha Barairat Dhaid Dibba Digdaga Falaj Almualla Hamraniyah Masafi Masfut Meleiha U.A.Q Mean maximum Mean Mean minimum

Min 33 30 43 38 38 37 32

38 35 33 32 51 51

37 30

Jan Max 93 88 85 93 83 95 93

92 89 91 89 87 95

90 83

89 83

89 89 92 88 86 96

Feb Max 93 85 84 90 83 96 93

34 25

34 31 29 27 50 50

Min 30 25 40 30 39 37 31

86 79

87 81 86 83 84 94

Mar Max 89 79 82 87 84 94 90

29 18

27 24 25 23 50 50

Min 23 18 35 30 33 29 25

79 61

83 61 71 76 84 92

Apr Max 86 70 83 77 81 92 84

21 13

19 17 18 16 43 43

Min 15 13 26 21 26 23 19

72 55

75 55 60 68 81 86

May Max 82 63 69 65 79 86 78

18 10

17 15 13 14 39 39

Min 11 10 22 18 23 20 16

76 62

80 62 67 72 83 90

Jun Max 86 65 67 70 83 90 82 79 74 76 73 78 89

Jul Max 82 67 72 75 82 89 79

17 77 3.0 67

18 16 14 12 42 42

Min 12 9.0 24 20 3.0 21 16

26 15

25 23 25 17 42 42

Min 16 15 34 27 42 27 20

80 69

81 81 83 75 84 89

Aug Max 85 69 79 74 82 89 83

29 17

26 27 28 19 43 51

Min 18 17 34 34 51 29 21

82 72

81 77 82 82 84 92

Sep Max 89 72 82 75 82 92 86

25 14

24 21 22 15 44 44

Min 14 15 32 26 42 26 18

84 73

89 73 83 90 83 95

Oct Max 91 75 82 84 78 95 89

23 12

22 19 17 17 44 44

Min 16 12 30 24 31 24 18

87 80

90 83 89 93 85 95

Nov Max 93 83 80 85 81 95 90

29 20

32 28 25 26 43 43

Min 24 20 36 29 33 30 25

89 82

87 88 91 95 90 95

Dec Max 92 87 84 89 82 94 88

Table 4.4a  Average percentage of maxima and minima relative humidity (%) at some meteorological stations in the UAE for the period 1976–2003

37 28

35 37 34 36 51 51

Min 33 28 43 36 41 38 30

130 4  Climate Conditions and Their Impact on Water Resources

Station Al Gheweifat Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Mukhariz Owtaid Mezaira Madinat Zayed Abu Al Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul

62 58 48

54 48

36

30 34 36 42

46

32 51

46 39 31

89 86 84

89 77

91

88 89 90 94

98

92 80

69 90 84

85 85 79

86 81

88

83 86 86 92

86

90 86

92 90 85

55 30 22

23 48

41

21 25 26 36

24

50 63

59 54 42

89 81 69

76 80

86

73 79 79 85

80

88 89

89 89 82

51 22 15

14 42

33

15 15 18 30

16

44 61

51 43 31

91 71 58

68 77

83

65 73 72 79

75

85 88

88 87 76

46 17 11

11 36

26

12 12 14 22

12

37 57

48 33 23

86 65 53

62 76

83

59 69 66 73

68

83 87

85 86 73 85 90

84 87 75

85

64 74 71 80

37 90 13 74 8.0 58

7.0 67 34 78

22

8.0 8.0 10 17

8.0 73

33 49

42 26 18 86 91

85 87 79

85

63 75 70 78

43 92 13 72 6.0 57

6.0 62 42 79

28

7.0 6.0 8.0 16

7.0 72

40 62

40 31 22

54 16 11

10 40

29

9.0 9.0 12 20

10

42 71

44 32 25

93 68 60

63 78

84

66 82 73 83

81

89 91

87 88 82

56 18 14

12 34

26

11 11 13 21

12

44 75

48 39 30

90 84 68

82 79

87

83 92 88 92

89

87 87

84 83 78

57 17 12

12 42

31

11 12 14 21

12

48 66

46 41 33

84 87 69

86 78

87

85 92 91 94

90

88 80

83 82 78

53 19 14

15 44

35

15 16 17 24

15

49 52

48 44 35

78 87 77

88 76

85

86 91 89 92

89

86 73

83 80 76

50 31 25

26 46

41

26 30 30 36

28

51 40

51 48 43

33 52

49

32 39 38 45

36

57 46

55 55 50

71 48 92 40 87 32 (continued)

94 79

86

91 94 93 96

92

89 75

87 85 80

January February March April May June July August September October November December Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min 40 92 31 86 22 81 18 74 11 74 10 78 13 89 18 90 20 91 23 90 35 93 43 93

Table 4.4b  Average percentage of maxima and minima relative humidity (%) at major meteorological stations in the UAE for the period 2003–2015

4.5 Wind Speed 131

Rezeen Abu Dhabi Airport Al Quaa Al Khazna Al Arad Damsa Sweihan Saih Al Salim Al Ain Airport Al Faqa Dubai Airport Sharjah Airport Umm Al Quwain Al Malaiha Hatta Fujairah Airport Masafi Mobreh Mountain

Station

31 44

36 38 34 34 36 34

38

40 45

45

50

35 38 46

36 30

87 87

91 92 89 97 91 90

87

93 82

89

88

88 82 76

80 84

75 76

83 79 78

88

89

88 83

81

85 86 83 90 86 87

84 85

29 24

27 35 46

46

42

31 43

30

27 30 26 25 28 25

24 40

65 61

78 71 78

88

86

83 82

75

78 83 77 85 82 82

81 83

20 16

20 23 39

41

37

24 38

24

19 22 18 18 20 19

16 33

58 55

70 62 74

81

80

72 76

61

68 75 68 79 74 77

75 78

14 15

15 18 30

33

29

19 31

18

15 17 14 13 16 14

12 26

51 52

62 53 72

75

75

63 72

53

63 73 65 73 68 70

70 75

10 11

11 12 25

28

25

14 27

13

11 12 10 9.0 11 10

62 57

70 66 78

81

80

74 78

61

68 81 70 78 76 77

7.0 75 21 80

70 77 82

80

78

71 75

62

63 76 65 78 73 74

13 74 9.0 57

12 17 33

32

27

15 30

14

10 13 10 9 12 12

8.0 72 25 78

23 14

17 34 51

33

29

19 32

18

15 17 14 11 16 15

10 26

77 58

69 80 85

79

78

71 74

58

64 69 62 70 67 71

68 76

27 17

18 40 58

35

30

20 31

18

17 18 16 14 16 15

11 26

75 60

80 80 83

87

85

82 81

67

73 85 73 84 82 84

81 84

19 13

16 30 51

40

30

19 31

17

16 17 14 12 15 15

11 26

70 61

80 78 76

88

87

87 81

71

79 88 77 87 83 86

86 84

19 17

18 26 42

42

32

21 34

19

18 20 16 15 17 17

14 30

75 77

81 81 73

85

86

89 79

79

86 89 83 90 85 86

86 83

29 26

28 32 44

46

38

32 39

29

30 31 27 26 28 27

25 38

80 84

87 82 75

87

88

94 82

85

92 94 91 96 91 90

92 86

37 28

36 37 46

51

44

40 45

37

38 40 35 33 37 34

33 45

January February March April May June July August September October November December Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min

Table 4.4b (continued)

132 4  Climate Conditions and Their Impact on Water Resources

Ras Al Khaimah Jais Mountain Mean maximum Mean Mean minimum

47

29

62

41 29

90

86

98

87 69

85 75

92

76

89

35 21

63

24

43

80 60

89

60

86

28 14

61

18

37

74 55

91

58

78

22 11

57

18

28

69 51

87

56

70

90

60

75

18 74 7.0 57

49

18

23

92

59

73

20 74 6.0 57

62

14

26

93

62

73

24 75 9.0 58

71

16

30

26 11

75

19

32

81 60

92

60

82

25 11

66

16

31

82 61

94

62

83

27 14

53

20

32

83 73

92

79

85

35 25

51

27

38

87 71

96

85

88

41 28

57

28

46

4.5 Wind Speed 133

134

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.5a  Mean minimum and mean wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 1976–2003

Fig. 4.5b  Mean minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 2003–2015

felt in the interior. The coastal areas are subject to local sea breezes and have a wind regime of their own. The highest mean wind speed is 18.3 km/hr at Jabal Al Dhanah in March, and the lowest is 0.74 km/hr at Kalba in September. The mean minimum, mean and mean maximum wind speed (km/hr), at the main meteorological stations during the period 1979–2015, are listed in Tables 4.5a and 4.5b.

4.6  Evaporation Annual evaporation rates are higher than the mean annual rainfall all over the UAE. The average annual evaporation is 3322 mm, while the mean annual rainfall is 99 mm for the period 1976–2015. Since all contributing factors, such as air tem-

Month Al Hibab Al Oha Barairat Dhaid Dibba Digdaga Falaj Almualla Hamraniyah Masafi Masfut Meleiha U.A.Q Mean maximum Mean Mean minimum

6.4 2.9 2.4 0.2

7.5 3.4 3.0 0.0

3.0 5.4 5.0 2.0 7.0 7.0

7.8 4.0

5.0 9.0 9.0 7.0 13.0 13.0

3.5 0.2

3.0 5.0 4.0 2.4 8.3 8.3

7.6 4.0

6.0 8.0 8.7 7.0 10.4 14.3 3.4 0.2

7.7 3.9

3.4 0.2

3.5 5.0 4.0 5.9 7.6 5.6 3.5 9.0 3.7 1.9 7.6 2.0 7.8 12.0 9.0 7.8 14.8 9.0 7.8 4.1

4.8 9.0 10.6 7.0 10.7 12.4 3.7 0.2

7.7 4.1

3.6 0.2

4.0 5.4 2.2 5.0 10.6 7.0 3.9 9.6 4.0 2.8 7.0 3.0 8.1 10.7 8.3 8.1 10.7 8.3 8.0 4.0

6.3 11.9 11.9 7.0 10.4 11.9 3.6 0.2

3.7 6.5 3.9 2.4 8.0 8.0

6.7 3.0

5.2 9.0 9.6 6.0 9.8 9.8

3.0 0.2

2.6 4.8 4.0 2.2 7.0 7.0

5.7 2.8

2.4 0.2

0.2 4.0 3.0 1.0 6.0 6.0

5.5 2.0

3.5 7.0 6.9 4.8 10.4 10.4

2.3 0.2

2.2 4.0 2.8 1.0 7.2 7.2

3.9 7.0 6.9 4.8 9.6 9.6

5.0 8.0 9.0 7.0 12.0 16.0

3.9 7.6 8.0 5.4 11.7 11.7

2.6 5.0 3.5 1.9 6.0 6.0

October November Max Min Max Min 6.0 3.0 6.0 2.0 4.0 0.6 3.5 0.2 5.0 0.2 4.0 0.2 5.0 4.0 6.0 3.0 9.0 4.0 9.0 3.5 2.8 0.4 2.0 0.9 4.0 2.2 3.0 1.0

January February March April May June July August September Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min Max Min 7.6 2.4 7.0 4.0 9.0 4.0 8.1 3.0 9.0 3.9 9.5 4.0 9.0 4.4 8.0 3.5 7.0 3.5 3.9 0.7 6.0 2.0 6.0 2.0 4.8 1.0 6.0 1.0 6.0 0.9 6.0 0.7 6.0 1.0 5.4 0.9 5.4 0.2 5.4 0.0 6.0 0.2 8.9 0.2 6.0 0.2 8.0 0.2 6.3 0.2 7.0 0.2 5.4 0.2 5.4 4.0 7.0 5.0 7.0 5.0 7.0 4.0 7.0 5.0 7.0 5.0 8.1 5.4 7.6 6.0 6.9 4.6 11.3 5.4 16.0 4.0 13.0 6.0 14.3 6.0 14.8 1.3 12.4 5.4 10.6 4.0 9.5 4.0 8.9 3.9 2.4 0.7 3.0 0.9 4.0 1.0 4.0 1.5 3.9 1.5 4.1 1.9 4.1 0.9 4.0 0.6 3.0 0.6 3.9 1.9 4.0 2.4 5.0 1.0 4.0 2.0 5.0 3.0 5.0 3.0 5.0 3.3 6.0 3.7 4.0 2.2

Table 4.5a  Average minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 1976–2003

5.8 3.0

4.0 6.9 7.0 5.4 10.4 10.4

2.4 0.2

0.7 4.0 3.9 1.5 7.0 7.0

December Max Min 6.0 1.9 4.0 0.2 5.0 0.2 5.0 3.5 9.0 2.8 3.9 0.6 3.0 1.9

Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Mukhariz Owtaid Mezaira Madinat Zayed Abu Al Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul

Al Gheweifat

Station

18 17 17 19 20

15

14 11 10 11

16 10 14

14 14 10

28 29 29 27 31 33

30

26 24 19 25

27 23 23

25 27 19

15

27 29 21

30 25 26

29 25 22 27

32

31 31 29 34 34

31

16 15 11

18 11 15

16 12 11 12

17

18 18 18 21 21

17

28 31 22

32 26 26

31 26 23 29

34

30 31 31 36 34

32

16 16 11

18 11 15

17 13 12 13

18

17 18 20 22 20

17

28 33 24

34 28 26

34 28 24 31

35

29 30 31 35 33

31

15 16 11

17 12 13

17 13 12 13

17

15 16 19 19 18

16

28 35 24

32 29 24

34 29 26 33

35

26 29 29 33 32

31

16 15 11

17 12 13

16 12 12 13

17

14 15 18 18 18

16

26 36 26

32 31 24

37 31 28 33

38

27 28 29 33 31

32

14 16 11

17 13 14

17 13 13 14

17

15 15 18 19 18

16

21 35 25

32 29 25

34 29 27 32

37

26 27 28 32 27

30

12 16 11

17 12 14

15 12 12 13

17

14 15 16 17 15

15

23 33 24

32 27 25

34 29 24 32

37

25 25 27 31 24

26

13 14 11

16 11 14

15 11 10 13

16

14 13 16 17 12

12

22 31 21

29 25 24

31 25 22 31

33

25 24 24 29 26

26

12 13 9.0

15 10 13

13 10 10 12

14

14 13 14 16 14

13

21 28 19

25 22 22

27 22 19 28

29

24 22 22 27 25

24

12 12 8.0

14 8.0 13

12 9.0 9.0 10

13

13 12 14 16 14

12

24 26 18

26 21 23

27 21 18 26

29

29 27 25 29 31

26

13 12 9.0

14 9.0 13

13 9.0 9.0 11

14

18 15 15 18 18

14

23 26 18

26 22 23

26 21 18 25

27

31 28 25 31 34

26

13 13 9.0

15 10 14

13 10 10 11

14

19 17 15 19 21

15

January February March April May June July August September October November December Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean

Table 4.5b  Average minimum and maximum wind speed, in km/hr, at major meteorological stations in the United Arab Emirates for the period 2003–2015

Rezeen Abu Dhabi Airport Al Quaa Al Khazna Al Arad Damsa Sweihan Saih Al Salim Al Ain Airport Al Faqa Dubai Airport Sharjah Airport Umm Al Quwain Al Malaiha Hatta Fujairah Airport Masafi Mobreh Mountain Ras Al Khaimah

10 6.0

9.0 8.0 9.0 8.0 8.0 11 6.0 8.0 6.0 5.0

11

9.0 12 7.0

7.0 19

4.0

23 12

20 17 21 19 21 26 12 19 11 10

23

23 26 12

18 35

10

11

20 40

25 26 13

25

21 18 24 23 24 28 13 21 13 12

24 13

4.0

8.0 22

9.0 13 7.0

12

10 9.0 11 10 9.0 13 7.0 9.0 7.0 6.0

11 7.0

11

21 39

26 26 13

27

22 19 25 24 25 29 14 23 13 12

26 14

5.0

9.0 22

10 13 7.0

12

10 9.0 11 10 10 13 8.0 10 7.0 6.0

12 8.0

11

23 40

28 29 14

27

22 20 27 25 26 32 15 23 13 12

27 14

5.0

10 23

10 13 7.0

12

10 9.0 11 10 10 13 8.0 10 7.0 6.0

11 7.0

12

23 38

29 29 14

27

23 20 28 28 27 33 16 25 13 13

28 14

5.0

10 22

11 14 7.0

12

9.0 9.0 11 10 10 14 8.0 10 7.0 7.0

11 7.0

12

22 32

28 29 12

26

24 20 29 28 26 31 16 24 13 12

29 14

5.0

10 18

11 14 6.0

12

10 8.0 12 10 10 13 7.0 10 7.0 6.0

12 7.0

12

21 28

28 28 10

27

25 20 28 26 26 31 15 23 13 12

28 14

5.0

10 16

11 15 5.0

13

11 9.0 12 10 11 13 8.0 10 7.0 6.0

12 7.0

12

21 26

29 27 10

27

24 19 26 27 27 30 15 23 13 12

27 14

5.0

10 14

11 14 5.0

12

11 9.0 12 10 11 13 8.0 10 7.0 6.0

12 7.0

12

20 25

27 26 9.0

25

21 18 25 25 26 29 15 23 13 12

26 13

4.0

9.0 14

9.0 12 4.0

11

9.0 8.0 11 9.0 10 11 7.0 9.0 6.0 6.0

10 7.0

11

20 26

26 24 9.0

24

18 17 22 22 24 27 13 21 12 11

22 12

4.0

8.0 14

8.0 11 4.0

10

7.0 7.0 9.0 8.0 8.0 10 7.0 8.0 6.0 5.0

9.0 6.0

10

18 29

23 24 10

23

17 16 21 20 21 25 12 18 11 10

21 12

3.0

7.0 17

8.0 10 5.0

11

7.0 7.0 9.0 8.0 7.0 10 6.0 8.0 6.0 5.0

9.0 6.0

9.0

17 31

21 23 11

22

18 15 21 20 20 24 11 18 11 10

22 11

3.0

7.0 17

8.0 11 6.0

11

8.0 7.0 9.0 8.0 7.0 10 6.0 7.0 6.0 5.0

10 6.0

Jais Mountain Mean maximum Mean Mean minimum

Station

15 20

11 4.0

29 35

22 10

24 11

29 40

13 4.0

15 22

25 11

29 39

13 5.0

15 22 26 11

29 40 13 5.0

14 23 26 12

26 38 12 5.0

12 22 26 12

22 38 12 5.0

11 19 25 10

21 37 12 5.0

10 17 25 10

20 37 11 5.0

9.0 17

23 9.0

19 33

11 4.0

9.0 16

21 9.0

19 29

10 4.0

9.0 16

21 10

22 31

10 3.0

11 18

21 9.0

24 34

11 3.0

12 21

January February March April May June July August September October November December Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean Max Mean

Table 4.5b (continued)

4.7 Evapotranspiration

139

Fig. 4.6  Mean minimum, mean and mean maximum monthly evaporation (mm) for the period 1976–2003

perature, humidity and wind speed, are highly favorable, evaporation is extremely high in UAE. The western coast has the lowest annual average pan evaporation of 7.5–8.0 mm/d. In contrast, the eastern coast has a much higher evaporation rate of 9.0–9.5 mm/d, because of high wind speed. In the eastern mountains, western gravel plains and desert foreland, evaporation ranges from 10 to 11 mm/d, while evaporation rates in the western and southwestern desert regions are the highest in the country, reaching 12 mm/d. In Al Ain, the highest evaporation rate of 13 mm/d was recorded during June, decreasing to 4 mm/d during December and January (Fig. 4.6). Using a pan coefficient of 0.6 (Ministry of Agriculture and Fisheries 1993, 2001), Garamoon (1996) estimated the daily evaporation in Al Ain City as 10 mm.

4.7  Evapotranspiration Evapotranspiration (ET) calculated by various methods is higher in summer than winter. This pattern is largely related to the amount of solar-energy supply. The ET varies regularly throughout the year, from average low values of 87 mm in January and 86 mm in February to peak values of 234 mm in June and 238 mm in July at the eastern region of the UAE along Gulf of Oman coast. Average evapotranspiration increases rapidly from 122 mm in March to 215 mm in May and decreases from 180 mm in September to 96 mm in December. The total annual evapotranspiration for the east coast is 1909 mm and the average monthly value is 159 mm (Fig. 4.7).

140

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.7  Calculated monthly potential evapotranspiration, mm, at 11 major meteorological stations in the UAE in 1988. (Data from Garamoon 1996)

The average annual evapotranspiration in northern UAE is 1969 mm, with a minimum of 80 mm in January, a maximum of 262 in July and an average monthly value of 164 mm. In central UAE, the annual average evapotranspiration is 2124 mm, with a minimum of 83 mm in January, a maximum of 285 in July and an average monthly value of 177 mm. In the Al Ain area, the average annual ET is 1996, with minimum of 69 mm in December and a maximum of 278 in July (Alsharhan et al. 2001). The average annual evapotranspiration in UAE varies between 1909  mm and 2124 mm, with minimum values along the eastern coast and maximum values in interior UAE. The evapotranspiration along the eastern coast is lower in summer and higher in winter compared to the rest of the country. The overall average evapotranspiration for the UAE is 2024  mm. Garamoon (1996) used climatological data with the Thornthwaite (1948) equation for estimation of potential evapotranspiration at five meteorological stations in Al Ain area (Chow et al. 1988). The results are illustrated in Table 4.6. The reference crop evapotranspiration is the rate of evaporation from an extended surface 8–15 cm tall, with a green grass cover of uniform height, actively growing, completely shading the ground and no soil moisture deficit. At Al Dighdaga area in Ras Al Khaimah the average monthly reference crop evapotranspiration varies from 2  mm/day in January to 10  mm/day in July and annual value reached up to 2120 mm/year.

4.8 Rainfall

141

Table 4.6  Calculation of monthly and annual potential evapotranspiration (in mm), at eight major meteorological stations in the UAE in 1988 (data collected by Garamoon 1996) Station Al Ain Al Oha Abu Dhabi BA Dubai Airport Hibab Masfut Falaj Al Mualla Al Wagan Ain Sukhanah Al Hayer Asab

Month J F 21 27 20 30 28 34 29 33 24 30 24 30 25 27 20 29 20 28 21 29 18 21

M 72 67 73 69 68 67 66 69 71 61 70

A 139 148 146 128 139 147 135 144 141 125 135

M 279 300 291 263 279 331 276 290 280 264 169

J 396 428 365 342 383 433 379 399 397 459 382

J 506 579 468 463 490 455 503 543 522 587 530

A 463 541 458 443 464 392 455 502 480 512 531

S 314 351 326 306 303 283 300 333 321 338 407

O 160 193 190 184 162 174 174 177 170 184 221

N 64 73 85 86 68 71 74 68 66 65 86

D Sum 30 2469 29 2758 42 2505 44 2390 32 2442 35 2441 34 2448 30 2604 30 2526 36 2679 39 2994

4.8  Rainfall The principal rain in UAE falls between November and March, with the maximum intensity during February and March. About 90% of precipitation falls during winter and spring. About 60% of rain falls between February and March, making it the rainiest period in the country. In rare instances, heavy rainstorms may affect northern UAE, during which snow and hail balls may cover high mountain peaks (+2000 m) of Ru’us Al Jibal in Ras Al Khaimah area. There are 37 fully-equipped meteorological stations in the UAE (Table  4.7), while the others are rainfall recording stations (Fig.  4.1). Figures  4.8a and 4.8b show that February is the rainiest month, with an average of 37.9 mm, while June is the driest month, with an average of 0.3 mm. During wet years, there may be as many as nine rainy days in the winter months, although more than 6 days is not common. The mean annual rainfall for the UAE is about 100 mm for the period 1976–2015. However, rainfall is extremely variable in space and time, depending on the climatic conditions, geographic location, local topography and the rainfall-­ driving mechanism (Rizk et al. 1997). Rainfall is well over average in the eastern and northeastern mountains, followed by the eastern coast and gravel plains. Rainfall is below average along the western coast and substantially lower in the western and southwestern desert regions (Table 4.8). In 1981–1982, rainfall totaled 282 mm in the mountainous regions, increasing to 450 mm in some parts. In contrast, the period 1984–1985 was a very dry season with a mean annual rainfall of 24 mm and Abu Dhabi recording 6 mm. The average annual rainfall decreases from 160 mm in the northeastern part of the country to less than 40 mm in the southwest. Winter rainfall is generally light to moderate and widespread in nature, being of a frontal nature as the dry polar air masses meet the warm moist air of the Arabian

142

4  Climate Conditions and Their Impact on Water Resources

Table 4.7  Locations of major meteorological stations used for investigation of climate conditions in the United Arab Emirates during the period 2003–2015 No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Station Name Al Gheweifat Al Qlaa Abu Dhabi corniche Umm Al Quwain Makassib Dalma Sir Bani Yas Abu Al Bukhoosh Abu Al Abyad Sir Bu Nair Abu Dhabi Dubai Sharjah Ras Al Khaimah Fujairah Al Ain Al Jazeera B. G. Mukhariz Owtaid Madinat Zayed Mezaira Hamim Bu Humrah Rezeen Um Azimul Al Quaa Al Arad Al Khazna Damsa Swiedan Saih Al Salem Al Faqa Hatta Al Malaiha Masafi Mebreh Mountain Jais Mountain

Type Coast Coast Coast Coast Island Island Island Island Island Island Airport Airport Airport Airport Airport Airport Land Land Land Land Land Land Land Land Land Land Land Land Land Land Land Land Land Land Land Mountain Mountain

Longitude (East) 51° 37′ 37″ 52° 58′ 47″ 54° 19′ 40″ 55° 39′ 13″ 51° 49′ 27″ 52° 17′ 29″ 52° 35′ 52″ 53° 08′ 45″ 53° 47′ 27″ 54° 13′ 02″ 54° 39′ 04″ 55° 21′ 52″ 55° 31′ 02″ 55° 56′ 20″ 56° 19′ 26″ 55° 36′ 33″ 52° 17′ 20″ 52° 52′ 12″ 53° 06′ 10″ 53° 41′ 55″ 53° 46′ 43″ 54° 18′ 10″ 54° 31′ 48″ 54° 44′ 44″ 55° 08′ 19″ 55° 25′ 10″ 55° 31′ 27″ 55° 06′ 48″ 55° 24′ 48″ 55° 24′ 53″ 55° 24′ 53″ 55° 37′ 17″ 56° 08′ 15″ 55° 53′ 17″ 56° 07′ 17″ 56° 07′ 46″ 56° 10′ 20″

Latitude (North) 24° 07′ 16″ 24° 09′ 19″ 24° 28′ 38″ 25° 31′ 60″ 24° 39′ 59″ 24° 29′ 27″ 24° 19′ 01″ 24° 29′ 42″ 24° 12′ 22″ 25° 13′ 12″ 24° 25′ 59″ 25° 15′ 10″ 25° 19′ 43″ 25° 36′ 49″ 25° 06′ 44″ 24° 15′ 42″ 23° 17′ 28″ 22° 55′ 48″ 23° 23′ 44″ 23° 40′ 54″ 23° 08′ 42″ 22° 58′ 25″ 23° 30′ 21″ 23° 40′ 39″ 22° 42′ 51″ 23° 23′ 36″ 23° 50′ 41″ 24° 07′ 29″ 24° 10′ 48″ 24° 27′ 58″ 24° 27′ 58″ 24° 43′ 08″ 24° 48′ 40″ 25° 07′ 50″ 25° 07′ 02″ 25° 38′ 49″ 25° 57′ 00″

Elevation (meter) 45 15 7.0 20 5.0 5.0 123 37.0 20.0 7.00 27.0 19.0 34.0 31.0 46.0 265 70.0 145 180 170 204 126 150 117 130 140 180 170 153 170 80.0 235 305 150 525 1433 1720

Gulf. The source of this rain can be characterized geochemically by the study of oxygen and deuterium stable isotopes. The intensity of precipitation is directly proportional to the temperature difference between the converging weather fronts, which tends to be less intense as the

4.8 Rainfall

143

Fig. 4.8a  Mean minimum, mean and mean maximum monthly rainfall (mm) in UAE for the period 1976–2005

Fig. 4.8b  Mean minimum, mean and mean maximum monthly rainfall (mm) in UAE for the period 2003–2015

Arabian Gulf, which is relatively small in size and shallow in depth, is incapable of producing large temperature gradients. Summer rainfall occurs as heavy isolated events associated with the passage of the retreating monsoon or as a result of convection giving rise to a lifting mechanism. This rain is confined to the mountains and foothill areas. The eastern mountain ranges in the UAE also provide a natural topographic high, forcing the air upwards, ultimately producing orographic rainfall. This explains why these moun-

144

4  Climate Conditions and Their Impact on Water Resources

Table 4.8  Monthly rainfall records (in mm) from 34 metrological stations during the period 2003–2014. These data have been presented in Fig. 4.9 Year 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Max Ave. Min.

Year Jan 3.44 14.50 19.27 0.84 1.63 45.78 19.62 3.67 11.10 1.75 1.46 10.70 45.8 11.1 0.8

Feb 3.47 0.00 17.68 20.73 8.10 0.30 1.19 12.21 1.47 1.57 3.19 3.60 20.7 6.1 0.0

Mar 9.06 1.06 6.93 8.31 18.82 0.00 30.96 16.68 0.31 0.89 2.11 2.40 31.0 8.9 0.3

Apr 48.86 2.15 2.30 1.01 2.93 0.30 10.71 1.52 6.94 4.87 19.00 6.40 48.9 8.9 0.3

May 0.30 0.80 2.21 0.20 1.33 1.27 0.80 1.21 1.16 2.99 3.43 2.10 3.4 1.5 0.2

Jun Jul 0.0 7.10 2.36 5.37 5.35 9.42 10.93 2.08 5.49 2.49 0.00 6.73 1.15 4.01 1.63 3.76 0.32 3.57 1.97 2.30 1.40 4.90 2.60 6.80 10.9 9.4 3.3 4.9 0.3 2.1

Aug 2.46 3.55 4.09 7.40 5.25 9.55 0.80 2.40 10.84 4.30 11.40 8.00 11.4 5.8 0.8

Sep 1.50 4.76 4.98 11.32 4.19 7.04 4.75 1.37 5.74 20.56 7.10 5.67 20.6 6.6 1.4

Oct 5.73 4.58 6.12 3.86 7.00 0.0 1.58 5.11 8.79 8.24 6.20 3.00 8.8 5.5 1.6

Nov 3.00 6.78 6.23 8.53 0.57 4.22 2.88 7.91 4.37 5.91 40.1 6.30 40.1 8.1 0.6

Dec 7.50 22.7 6.84 55.0 1.80 8.46 32.9 1.83 0.57 3.78 5.70 1.70 55.0 12.4 0.6

Fig. 4.9  Average monthly rainfall (in mm) records in 34 metrological stations in UAE during the period 2003–2014

tains act as a barrier that prevents the influence of the Gulf of Oman beyond the eastern coastal plain, which, in spring, has more rainfall than any other region in the UAE (Fig. 4.9). The records of major meteorological stations during the period 1976–2015 reveals that rainfall exhibits wide variations in space and time (Figs.  4.10a and 4.10b; Tables 4.9a and 4.9b). The records also showed the presence of cycles of about 10 years during which above average rainfall occurs at all meteorological

4.8 Rainfall

145

Fig. 4.10a  Mean annual rainfall (mm) records for the period 1976–2003, showing the wide variation in average annual rainfall in 19 meteorological stations

Fig. 4.10b  Mean annual rainfall (mm) records for the period 2003–2015, showing the wide variation in average annual rainfall in 30 meteorological stations

198.8

92.70

58.30

184.3

84.40

250.6

271.3

13.80

28.20

43.90

131.8

161.7

48.90

1976– 133.9 1977

1977– 69.90 1978

1978– 58.10 1979

1979– 78.50 1980

1980– 136.3 1981

1981– 259.6 1982

1982– 249.6 1983

1983– 56.40 1984

1984– 6.20 1985

1985– 80.80 1986

1986– 190.2 1987

1987– 208.0 1988

1988– 66.80 1989

Year

86.00

225.6

157.4

88.60

30.40

40.80

219.6

329.4

111.6

156.4

46.60

79.90

157.0

60.00

240.6

152.8

50.60

25.40

24.20

157.6

317.1

101.3

74.80

45.70

101.5

99.70

70.70

15.80

231.2

–

–

–

–

–

–

–

–

–

–

79.40

306.0

292.8

92.40

14.60

18.60

264.4

341.2

112.2

150.2

–

–

–

70.00

212.0

63.40

66.00

14.80

34.60

251.0

246.2

96.40

86.60

90.40

96.60

246.5

65.00

242.4

158.8

77.60

33.60

110.4

249.5

348.2

95.00

124.6

111.8

209.2

263.1

108.7

175.4

129.3

23.80

43.90

17.00

198.9

197.5

–

–

–

–

–

65.2

170.4

141.6

55.1

17.6

8.7

189.5

243.8

82.1

125.1

72.2

86.2

–

83.00

197.0

167.6

64.20

54.40

30.60

188.0

381.0

80.40

154.6

74.80

46.40

129.2

96.20

176.0

148.6

25.20

57.80

21.20

216.1

297.0

77.90

147.6

84.30

72.30

234.7

–

–

–

–

135

4.30

10.7

11.0

3.00

–

70.40

–

–

–

–

–

480.0 –

428.0 –

73.00

238.9

180.5

74.50

38.60

–

137.8

262.0

65.50

–

–

–

–

84.80

126.8

122.7

52.20

14.00

1.20

164.7

240.5

60.80

68.40

29.60

46.80

104.3

–

–

–

1.60

63.90 46.70

226.5 182.5

169.9 98.20

42.40 24.90

24.50 5.90

7.10

125.3 104.9

193.9 183.1

62.30 –

78.20 –

–

–

–

Min

50.70 184.3 5.40

29.60 111.8 29.6

46.80 209.2 46.4

104.3 263.1 99.7

110.4 1.20 12.50 57.80 3.00

3.60

56.80 63.10 135.4 46.7

226.2 190.5 306.0 4.30

97.50 122.1 292.8 10.7

34.00 38.40 92.40 11.0

5.50

4.40

129.7 131.2 480.0 104.9

219.5 209.3 428.0 183.1

38.10 53.70 136.3 22.0

5.40

–

–

–

Abu Al Dubai Bateen Dhabi Wagan Al Oha Al Ain Ap Ap Ap Mean Max

22.00 –

–

–

–

–

Sharja Melieha Hamraniyah Dhaid Alhibab Alhaiyir Masfut Dibba Masafi U.A.Q Ap F. Almualla Barairat Asab

Table 4.9a  Maximum, mean, minimum average annual rainfall (mm) at major meteorological stations in the UAE for the period 1976–2004

132.7

114.8

195.2

202.9

49.20

128.4

395.4

186.0

347.0

90.20

20.00

48.60

29.60

2.00

1989– 251.1 1990

1990– 57.80 1991

1991– 158.1 1992

1992– 175.6 1993

1993– 54.60 1994

1994– 126.2 1995

1995– 436.6 1996

1996– 269.8 1997

1997– 244.2 1998

1998– 84.60 1999

1999– 20.00 2000

2000– 22.40 2001

2001– 66.20 2002

2002– 28.00 2003

43.0

0.0

36.0

1.20

77.00

208.4

267.2

414.8

208.1

56.00

129.0

133.8

84.60

156.4

57.40

48.20

18.60

4.00

42.20

204.0

222.6

356.2

85.60

35.90

177.9

170.0

64.40

182.8

60.6

57.6

17.0

8.00

14.60

144.2

219.7

223.9

113.8

102.6

152.4

151.7

67.30

102.5

96.60

88.80

92.50

66.20

301.8

254.2

336.7

257.8

139.4

147.7

131.5

100.8

185.0

37.6

34.6

45.4

8.00

109.2

271.1

318.0

548.2

210.4

97.60

133.6

166.2

82.00

160.0

77.2

40.6

70.4

5.80

71.20

293.0

244.6

506.8

266.6

75.00

155.0

143.2

79.80

291.0

44.40

8.80

121.8

10.80

73.40

344.4

201.8

398.1

77.90

39.10

187.2

185.4

43.70

186.7

–

23.40

23.00

1.80

65.70

229.0

199.8

337.9

145.8

32.5

133.7

132.6

39.9

193.3

37.60

29.20

89.80

0.20

46.80

292.0

197.4

408.0

151.8

96.20

213.4

149.2

63.70

223.4

88.60

13.60

66.60

3.40

29.40

296.6

195.0

350.0

119.4

52.40

208.2

164.6

66.20

126.6

–

–

–

1.00

–

–

–

–

–

–

–

34.1

5.60

52.1

116.5

76.00

24.00

–

30.80

31.80

161.2

52.70

63.30

1.00

55.00

120.1

49.60

72.90

108.8

71.80

30.40

–

33.60

145.0

208.5

189.6

182.6

15.80

204.2

127.7

48.30

191.0

0.60

73.60

20.90

7.40

55.60

93.20

291.1

222.4

185.1

51.50

167.5

105.7

62.80

201.2

–

16.00 –

34.10 –

32.70 5.70

4.20

45.00 –

193.5 120.4

192.0 79.60

354.9 156.9

86.70 62.30

13.00 67.40

132.1 4.50

132.0 106.4

54.50 25.80

209.9 62.20

33.80 139.4 1.00

(continued)

20.10 12.20 116.5 0.60

88.80 0.00

16.70 121.8 5.70

11.60 20.00 0.20

30.50 6.00

7.50

–-

16.40 39.00 109.2 14.6

150.2 139.3 347.0 31.8

81.40 161.0 318.0 79.6

158.0 223.1 548.2 52.7

86.60 105.2 266.6 62.3

3.10

112.9 104.3 213.4 4.50

110.2 113.6 195.2 34.1

12.40 38.90 114.8 5.60

50.60 131.0 291.0 50.6

–

395.4

130.0

2.00

2003– 39.30 2004

Mean 436.6 maximum

Mean 129.6

Mean 6.20 minimum

Year

0.00

127.4

414.8

23.3

4.00

111.8

356.2

9.60

2.20

97.5

231.2

2.20

2.60

161.4

341.2

2.60

8.00

140.6

548.2

–

5.80

158.0

506.8

13.6

8.80

128.1

398.1

–

1.80

112.6

337.9

–

0.20

135.2

408.0

–

3.40

123.8

350.0

29.60

1.00

98.9

480

–

Sharja Melieha Hamraniyah Dhaid Alhibab Alhaiyir Masfut Dibba Masafi U.A.Q Ap F. Almualla Barairat Asab

Table 4.9a (continued)

1.00

66.1

161.2

–

5.80

119.7

262.0

5.80

0.60

95.1

291.1

7.30

–

4.20

1.60

103.9 74.4

354.9 183.1

–

7.30

Min 39.30 2.20

3.10

72.0

3.60

78.5

20.00 0.00

204.9 32.6

226.2 223.1 548.2 183.1

–

Abu Al Dubai Bateen Dhabi Wagan Al Oha Al Ain Ap Ap Ap Mean Max

Station Al Gheweifat Makassib Dalma Sir Bani Yas Al Qlaa Abu Al Bukhoosh Al Jazeera B.G. Mukhariz Owtaid Mezaira Madinat Zayed Abu Al Abyad Hamim Abu Dhabi Corniche Sir Bu Nair Bu Hamrah Um Azimul Rezeen Al Quaa Al Khazna Al Arad Damsa Sweihan Saih Al Salim

January 9.40 8.80 4.10 6.50 2.40 11.5 6.40 6.20 11.4 3.70 6.40 8.80 8.80 10.6 2.90 1.90 2.90 7.90 2.60 12.1 7.60 5.00 8.50 4.00

February 6.3 5.4 2.1 2.3 0.4 1.9 3.0 2.0 4.3 2.8 3.0 5.2 5.4 3.8 2.3 1.6 2.5 4.0 2.1 7.7 5.8 1.4 7.8 2.4

March 7.40 2.00 4.40 3.40 5.60 6.00 4.40 2.50 5.10 2.10 4.80 2.10 6.30 5.60 5.30 3.00 1.40 7.40 7.70 16.5 14.0 5.20 11.0 8.60

April 3.70 2.30 4.00 3.90 4.50 1.90 1.80 6.70 16.0 2.20 7.60 2.20 10.2 8.40 2.80 13.6 16.4 16.6 29.9 14.6 19.3 2.90 12.3 5.30

May 0.1 0.0 0.6 0.1 0.1 0.5 0.0 0.1 0.3 0.1 0.3 0.0 0.0 0.0 0.2 0.2 0.5 0.2 0.0 0.2 0.8 0.1 0.3 0.0

June 0.0 0.0 0.0 0.0 0.0 0.0 1.2 0.5 4.7 0.0 0.0 0.0 0.0 0.0 0.0 0.6 0.2 0.5 0.1 0.1 0.2 0.1 0.0 0.0

July 0.0 0.0 0.0 0.0 0.0 0.0 1.2 0.4 0.5 0.6 0.1 0.0 1.2 0.0 0.0 0.3 3.5 0.2 6.2 0.5 2.3 1.1 1.1 0.0

August 0.0 0.0 0.0 0.0 0.2 0.4 2.1 2.1 9.4 2.1 1.2 0.0 8.7 0.0 0.0 1.2 4.4 3.2 1.7 5.1 1.60 2.40 3.40 0.00

September 0.0 0.0 0.0 0.3 0.0 0.0 0.4 1.6 0.2 2.6 0.3 0.0 0.3 0.0 0.0 1.1 0.0 0.0 0.0 0.1 2.7 0.0 0.9 0.1

October 0.0 0.0 0.9 0.0 0.0 0.9 0.0 0.0 0.0 0.0 0.0 0.0 1.9 0.0 0.4 1.3 0.1 0.0 0.2 0.0 0.0 0.0 0.3 0.0

November 8.50 4.00 23.4 10.7 3.60 14.5 1.60 1.40 9.40 1.80 4.10 4.10 0.20 2.90 13.1 1.10 1.20 1.60 7.90 1.40 0.90 1.20 4.30 1.90

Table 4.9b  Average monthly rainfall (mm) at 30 major meteorological stations in the United Arab Emirates for the period 2003–2015 December 6.70 7.60 9.40 8.00 6.40 11.7 2.50 3.40 4.30 3.60 6.80 4.40 5.00 18.8 6.40 2.90 5.10 9.50 3.40 11.6 6.70 2.50 11.7 6.10 (continued)

4.8 Rainfall 149

Station Al Faqa Umm Al Quwain Al Malaiha Hatta Masafi Mobreh Mountain Jais Mountain Mean maximum Mean Mean minimum

Table 4.9b (continued)

January 15.2 6.9 10.7 7.40 21.5 4.70 25.7 25.7 8.1 1.9

February 9.6 1.3 6.9 5.7 11.7 9.0 9.4 11.7 4.5 0.4

March 9.10 2.60 5.90 6.30 16.8 8.80 17.5 17.5 6.7 1.4

April 13.9 2.60 2.70 4.40 12.2 4.40 7.70 29.9 8.3 1.8

May 0.0 0.0 0.4 0.7 0.4 0.0 0.1 0.8 0.2 0

June 1.8 0.0 0.1 0.1 0.0 0.5 0.0 4.7 0.3 0

July 4.0 0.0 4.7 0.4 0.3 0.4 0.3 6.2 0.9 0

August 15.2 0.10 3.10 0.70 5.40 0.80 0.50 15.2 2.4 0.0

September 0.8 0.0 2.0 3.8 3.1 0.2 0.2 3.8 0.7 0.0

October 0.8 0.0 4.3 3.5 9.8 0.3 2.0 9.8 0.9 0.0

November 3.30 6.80 3.70 14.7 18.6 1.90 9.90 23.4 5.90 0.20

December 13.9 9.60 9.20 9.90 5.60 1.2.0 11.6 18.8 7.30 1.20

150 4  Climate Conditions and Their Impact on Water Resources

4.8 Rainfall

151

Fig. 4.11  Mean annual rainfall (mm) records for the period 1935–2015, showing the ten-­ year cycles; at the end of each cycle, rainfall exceeds the annual mean

Fig. 4.12  Predicted recurrence of rainfall maxima and minima, based on the records of 20 years of rainfall

stations in the country (Fig. 4.11). The importance of these cycles is that it produces enough rain that can contribute to groundwater recharge. The annual rainfall varies around its mean at all stations. This variation is not random but seems to follow regular cycles and El Nino teleconnections. Brook and Sheen (2000) reported similar rainfall cycles in the Sultanate of Oman. Therefore, analysis of the longest rainfall records leads to accurate predictions of cyclicity and frequency of rainfall records (Fig. 4.12). This figure shows the average rainfall in

152

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.13  Iso-hyetal contour map of annual rainfall in the United Arab Emirates for the period 1976–2015

the area of Al Ain as an example. Below the mean value, drought periods are expected and above it floods are predicted. The iso-hyetal map of UAE (Fig. 4.13) for the 1976–2015 period shows that the mean annual rainfall reaches its maximum (170 mm in Masafi) in the northeast and its minimum (16 mm in Bu Hasa) in the southwest. The quantity of annual rains falling on the UAE varies between 700–1480 Mm3 (Ministry of Agriculture and Fisheries 1993). The number of rainy days can reach nine and averages six. The mean annual rainfall in the UAE varies remarkably around its mean. To illustrate this, the authors divided the UAE into five geographic regions; each has three main meteorological stations. The northern region includes the Al Burayrat, Sharjah airport and Falaj Al Mualla stations. The central area includes the meteorological stations of Al Dhaid, Meleiha and Al Hibab. The southern region comprises Al Ain, Al Oha and Al Wagan stations. The eastern region contains the Dibba, Masafi and Masfut stations, and the western region includes the Dubai, Abu Dhabi and Asab stations (Fig. 4.1). Figures 4.14, 4.15, 4.16, 4.17, and 4.18 show the variations of rainfalls around their mean values in the five geographic regions during the period 1976–2003. Analysis of these figures indicates the following facts: • Annual rains exhibited a wide variation around their mean values, except the southern region, which includes the Al Ain, Al Oha and Al Wagan meteorological stations.

4.8 Rainfall

153

Fig. 4.14  Deviations from the mean annual rainfall (mm) in the meteorological stations of Al Burayrat, Sharjah airport and Falaj Al Mualla in the Northern Region of the United Arab Emirates for the period 1976–2003

154

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.15  Deviations from the mean annual rainfall (mm) at the meteorological stations of Al Dhaid, Meleiha and Al Hibab in the Central Region of the United Arab Emirates for the period 1976–2003

4.8 Rainfall

155

Fig. 4.16  Deviations from the mean annual rainfall (mm) at the meteorological stations of Al Ain, Al Oha and Al Wagan in the Southern Region of the United Arab Emirates for the period 1976–2003

156

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.17  Deviations from the mean annual rainfall (mm) at the meteorological stations of Dibba, Masafi and Masfut in the Eastern Region of the United Arab Emirates for the period 1976–2003

4.8 Rainfall

157

Fig. 4.18  Deviations from the mean annual rainfall (mm) in the meteorological stations of Abu Dhabi, Dubai and Asab in the Western Region of the United Arab Emirates for the period 1976–2003

• Rainfalls greatly exceeded annual means in the northern, central, eastern and southern regions during the 1981–1982 and 1995–1996 seasons, while the increase of rainfall above their annual means in the western region was during the 1982–1983 season only.

158

4  Climate Conditions and Their Impact on Water Resources

• The rainfalls were lower than their mean annual levels in the northern, central, eastern and southern regions during the seasons 1983–1984 and 1999–2000, while the rainfalls were lower than their annual means in the western region during the seasons 1983–1984 and 1990–1991. • At meteorological stations of the central region, the seasons 1984–1985 and 2000–2001 were the driest seasons compared to the 1983–1984 and 1999–2000 seasons, which were dry seasons too.

4.9  Global Warming and Climate Change Global warming and climate change are one of the most important challenges facing humanity in the present time and their negative impacts are already being felt around the globe. The UAE is an arid country with high temperatures and scarce rainfall. In the meantime, the country plays an important role in the energy market of the world as a major supplier of fossil fuel. This makes UAE one of the countries responsible for finding solutions to international problems such as global warming and climate change, while still providing many countries with the energy they need. The UAE is also at the heart of the clean-energy revolution by hosting the International Renewable Energy Agency (IRENA) and investing in ­renewable-­energy fields, because the nonconventional energy technologies will play a main role in economic growth in the next tens of years.

4.9.1  The Impacts of Climate Change The UAE realizes the adverse impacts of global warming and climate change, such as a rise of sea levels, scarcity of water resources, a decline of agriculture production, problems to human health and threats for animals and plant species, as well as crises for cities. Higher temperatures cause seawater expansion and the melting of mountain glaciers, causing a steady rise in sea level. Several low-lying countries such as The Netherlands and many small island states such as Bahrain will be at great risk if the current sea-level rise continues into the future. Global warming disrupts the current sensitive balance between water supply and demand and could widen the present deficit in water availability. The uneven distribution of water resources can become more serious increasing frequent floods in some places and severe drought, water shortage and desertification in others. In desert areas, which are experiencing water shortage in the present such as the UAE, the challenges of climate change and global warming are even greater. Global warming can increase harmful insects and weeds, which will negatively affect agricultural crops, leading to a global food shortage. Climatic change has

4.9 Global Warming and Climate Change

159

direct impact on human health caused by high temperatures, the flourishing of some disease carrying insects and scarcity of water that can make waterborne diseases more dangerous. Global warming can lead to extinction of some animals and plants and migration of some species to new areas for their more favorable climate. There will be also shift in forests and fruit and crop zones. The disruption in global temperature patterns will force the infrastructure in near sea-level coastal cities to adapt to the sea-level rise. In addition, energy consumption will be less in winter and greater in summer. The UAE established an Energy and Climate Change (ECC) directorate in the Ministry of Foreign Affairs to build the required capacity for managing climate change and renewable energy agenda. This new directorate is entitled to play a vital international role, in addition to its national responsibilities. The main national role is coordination with domestic key parties, while the international role involves negotiation and country representation. The international role of the UAE ECC directorate includes: collaboration with proactive international agencies and bodies; commercial representation in key strategic locations; an international presence in negotiations on climate change; monitoring developments, analysis of trends and preparation of reports on alternative energy and international climate change. The domestic role of the ECC directorate focuses on: engaging the government and private agencies in coordinating the development of domestic clean energy strategy and policies; involving all stakeholders in the development process of energy and climate change strategy and policies; and adopting national initiatives and assessment impacts of implementation. In 2016, the ECC was transferred to the Ministry of Climate Change and Environment.

4.9.2  The UAE Efforts to Mitigate Climate Change In 1995, the UAE ratified the Framework Convention on Climate Change. This convention aims to stabilize greenhouse-gas concentrations in the atmosphere at a level that would prevent dangerous changes to the environment due to human activities on the ecosystem. The UAE has also signed the Kyoto Protocol of the convention in 2005. This protocol identifies the obligations of the industrial countries to reduce their gas emissions. Scientific studies, prepared by the Inter-Governmental Panel on Climate Change and the National Aeronautics and Space Administration (NASA) in the United States, have proven the close correlation between increased greenhouse-gas concentrations and high temperatures. The chart shows the interrelationship between temperature and concentrations of carbon dioxide (MEW 2015). After water vapor, carbon dioxide (CO2) is the second major greenhouse gas, contributing 10–25% of the global warming. The mean annual deviations from the 1961–1990 average for global temperatures and carbon dioxide concentrations are illustrated in Fig. 4.19. The figure shows that the increase in global average surface

160

4  Climate Conditions and Their Impact on Water Resources

Fig. 4.19  Global average temperature and carbon dioxide (CO2) trends. (After Karl and Trenberth 2003)

temperatures coincides with the rise in CO2. Human activities increasing concentration of CO2 are responsible for about two-thirds of the greenhouse effect. The remaining one-fourth comprises ozone (O3), chlorofluorocarbons (CFCl3), methane (CH4) and nitrous oxide (N2O). According to Pielke et al. (2007), human activities contributing to the climate change include, but are not limited to, the storage and use of water for agriculture, gas emissions from burning fossil fuel and changes in land-use patterns. The UAE has responded and acted on mitigating the negative impacts of climate change in many ways. The following are a few examples: • Controlling emission by shifting from full reliance on conventional energy sources to developing renewable energy, mainly solar energy, such as Masdar City in Abu Dhabi and Solar Park in Dubai. • The UAE introduced nuclear power plants to meet increasing future electricity demand and to reduce carbon emission. Joining the nuclear club was necessary for the country in order to meet the escalating energy demand. The first nuclear power reactor entered service in 2018, and three others are under construction. • Masdar initiative and Masdar solar projects are cutting-edge renewable energy technologies intended to improve energy efficiency and conservation. The UAE aims at introducing new standards for appliances, such as air conditioning and other energy-intensive industries and activities. • Transportation is one of the fastest-growing sources of global gas emissions. The UAE has proposals for high-speed trains, in addition to the new mass transit system in Dubai. • The UAE has set, on a national level, new energy efficiency standards for building design. In addition to the Urban Planning Council (UPC), the UAE has developed the new “Estidama” (Arabic term meaning sustainability) initiative for designing sustainable buildings as the first national standard adopted in the Gulf region.

4.9 Global Warming and Climate Change

161

Table 4.10  Temperature increase in the UAE airports during the period 1975–2013 (data obtained from the National Center of Meteorology and Seismology) No. 1 2 3 4 5 6

Station Abu Dhabi Airport Dubai Airport Sharjah Airport Ras Al Khaimah Airport Fujairah Airport Al Ain Airport

Years of Records From To 1982 2013 1975 2013 1976 2013 1977 2013 1988 2013 1994 2013

Temperature Change (°C) 2.3 2.7 1.8 1.5 0.6 0.6

• The UAE is developing a major carbon capture and storage (CCS) project. Carbon capture and storage (CCS) is a means of facing the global warming problem by capturing carbon dioxide (CO2) from large point-pollution sources, such as power plants, and storing it safely underground. The potential positive impact of CCS is huge. The Inter-Governmental Panel on Climate Change says CCS could contribute 10–55% of the cumulative worldwide carbon-mitigation effort over the next 90 years. Technology for capturing of CO2 is already commercially available for large CO2 emitters, such as power plants.

4.9.3  Changes of Temperature in the UAE Analysis of the data collected by the National Centre of Meteorology and Seismology from stations based in airports, indicated a rise of 0.6–2.7 °C in temperature at all monitored stations. Examples are given in (Table 4.10).

4.9.4  National Communications In fulfilment of its obligations to the Framework Convention on Climate Change, the UAE prepared three national communications reports. In 2013, the UAE prepared last reports. Under the umbrella of Clean Development Mechanism projects for reduction in emission of greenhouse gases, the UAE was also engaged in the implementation of 14 projects. The positive environmental impact of these projects is a reduction total annual emission of carbon dioxide equivalent of about 1 million tons (Table 4.11). In her discussion of the impacts of climate change on urban development in Dubai, Alrustamani (2014) recommended having a central body to set policies, plan, monitor and coordinate successful implementation responses to the climate change. She called for further studies towards to achieve the following:

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Table 4.11  Total annual reduction in emission of greenhouse gases in the UAE during the period 1994–2005 Sector Energy

Industry

Agriculture

Land use

Waste

Total

Year 1994 2000 2005 1994 2000 2005 1994 2000 2005 1994 2000 2005 1994 2000 2005 1994 2000 2005

Total GHGs emitted in Kilo Ton CO2 CH4 N2O 60,246 396 5.0 96,240 796 10 128,824 1011 0.0 3443 1.00 0.0 6443 0.00 0.0 8623 0.00 0.0 0.00 48.0 2.0 0.00 80.0 9.0 0.00 75.0 8.0 −4227 0.00 0.0 −9665 0.00 0.0 −13,223 0.00 0.0 0.00 108 0.0 0.00 120 0.0 0.00 339 0.0 59,463 553 7.0 93,041 997 19 124,230 1425 20

CO2Eq 70,879 116,114 153,833 3455 6466 9426 1777 4348 3976 −4227 −9665 −13,223 2552 2622 71,122 74,436 119,885 161,134

• Building a national center for observation and monitoring climate change and identify major risks in each emirate. • Investing in research and development in each emirate and enhancing coordination between private sector and academic institutions to combat the negative impacts of climate change. • Presenting the strategies and progress made in UAE to the international community through the climate change committee. • Aligning efforts and implementation mechanism for long-term urban planning guided by the UAE vision 2021. • Identifying risks and setting priorities in line with the UAE government 2021 vision and the fast economic growth. • Involving public into the climate change dialog and encouraging participation of key players and stakeholders in sustainable development of the environment and natural resources. • Introducing subjects and practices in the schools’ educational programs to raise awareness of young generations and preparing them to participate in protecting the environment and facing the challenges of climate change. • Involving all family members, particularly women, in carrying out their responsibilities in preserving the environment and dealing with the impacts of climate change.

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The present UAE Cabinet includes a Ministry for Climate Change and Environment. The Ministry aims to enhance the efforts for tackling the climate-­ change problem through the implementation of sound policies and initiatives within a comprehensive national plan to mitigate and adapt to climate change and protect the environmental systems.

4.10  Impact of Climate Change on Water Resources Large changes in temperature and wide variability of rainfall can pose additional pressure on the limited conventional water resources in the country. Global warming and climate change are causes for serious concern and careful consideration in planning and management of water resources. Groundwater in the western coastal region is highly saline. Therefore, the impact of sea-level rise along the Arabian Gulf on the groundwater quality over the next century will be limited. The increase in water demand on conventional and nonconventional sources is a main concern resulting from climate change. While summer temperature is high in the UAE, climate change can lead to larger water consumption in winter due to increasing temperatures and decreasing precipitation. The climate change, along with the fast population growth, will also affect the per capita water demand. Dougherty et al. (2009) opined that the treated wastewater has to replace expensive desalinated water and depleting groundwater in forestry and irrigation.

4.10.1  Variations of Temperature and Rainfall The rainfall records in four meteorological stations in the UAE was studied by Ouarda et al. (2014). The variables analyzed were total annual, seasonal and monthly rainfalls; annual, seasonal and monthly maximum rainfalls; and the number rainy days per year, season and month. Results show that the annual rainfall series identify decreasing trends for all stations (Fig. 4.20). Although significant decreasing trends were identified with the classical and modified Mann–Kendall tests for all variables associated with the rainfall regime, the refinement of the methodology using the change-point detection procedure ended up showing that the true signal corresponds to a general increasing trend in these variables throughout the period of record, but with a downward jump around 1999. The impact of climate change on groundwater resources in Wadi Al Bih basin, Ras Al Khaimah area, was studied by Murad et al. (2014). Groundwater in the basin was sampled in 2005, 2011 and 2014, and some physiochemical parameters (TDS, EC, temperature and pH) were measured directly in the field during sampling.

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Fig. 4.20  Annual time series for all variables for selected stations in the United Arab Emirates. (After Ouarda et al. 2014)

Records of temperature and rainfall during the period 1997–2014 show a general rainfall decrease when the mean temperature increases, meaning that the UAE is expected to have less rainfall as temperatures continues to rise in the future. Results show that the mean average temperature during the last 17  years has increased 1.02 °C compared to the first 20 years. During the same period, a drastic drop in the average rainfall from 151.3 to 81.3 mm, means that the average rainfall decreased around 46% during the last 17-year period compared to the first 20 years (Fig. 4.21). Climate change may have also affected the groundwater salinity in the Wadi Al Bih basin during the period 1977–2014 and probably continues today (Murad et al. 2014). Measurements of groundwater salinity in 20 wells at Wadi Al Bih Basin in 2005, 2011 and 2014 reveal a steady increase in groundwater salinity in all sampling locations (Fig. 4.22). While the increase of groundwater salinity may reflect

4.10 Impact of Climate Change on Water Resources

165

Total Disolvedsolids TDS (ppm)

Fig. 4.21  Rainfall and mean temperature of the Ras Al Khaimah Emirate for the period 1977– 2014. (After Murad et al. 2014)

2005 2011 2014

9000 8000 7000 6000 5000 4000 3000 2000 1000 0

1

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Fig. 4.22  Measurements of groundwater Salinity in Wadi Al Bih basin in 2005, 2011 and 2014. (After Murad et al. 2014)

the effects of increasing temperature and decreasing rainfall, the effect of increasing groundwater exploitation from the aquifer on groundwater salinity should not be ruled out. Dougherty et al. (2009) studied the climate change in Abu Dhabi Emirate and predicted that the average monthly temperatures in 2050 will be higher than the period 1962–1990, 1.6 °C in January and 2.5 °C in September. In 2100, increases in average monthly temperature could be higher about 3.3 °C in February and 4.5 °C in October. In hot, dry climates, evaporation of irrigation water is a serious problem—whether from the soil, plant leaves or other open water bodies. Improving irrigation efficiency enables farmers to avoid severe water loss through natural evaporation.

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Rainfall in UAE exhibits wide variations in space and time. However, part of rainfall runs off, providing aquifer recharge under favorable conditions, especially in the northern and eastern mountain ranges where many drainage basins provide favorable areas for groundwater recharge. This recharge mechanism is important in Ras Al Khaimah, Fujairah and Al Ain areas. Murad et al. (2014) studied the climate change and fluctuations in rainfall patterns in Wadi Al Bih area and predicted diminishing of aquifers’ recharge as a result decreasing or absence of rainfall. The predicted variations in rainfall are greater than the projected fluctuation in temperature. However, some models project a wetter region with higher rainfall, while others project a dryer region with less rainfall. The mean annual rainfall in the UAE varies from less than 50 mm/year in the western region and 100–200  mm/year in the north and east. Dincer et  al. (1974) estimated that 100 mm/year of rain is required to cause sufficient runoff and aquifer recharge. Garamoon (1996) estimated that the minimum amount of rainfall that can cause surface runoff, leading to aquifer recharge, is about 90 mm/year in the northeastern part of the country, and about 70 mm/year in the central part and Jabal Hafit, south of Al Ain City in the eastern region of Abu Dhabi Emirate.

4.10.2  Decline of Aquifer Recharge During dry years, there may be no rain at all, while in wet years there may be as many as nine rainy days during the winter, although more than six days is not normal. Restoration of groundwater is impossible because groundwater exploitation far exceeds natural recharge (Alsharhan et al. 2001). The water balance of various aquifers depends on the aquifer matrix, proximity to recharge area and groundwater recharge and discharge. The groundwater quality depends on the aquifer type, groundwater residence time, recharge mechanism and human activities (ADEA 2006). Rizk et al. (1998) found that wadis of Shik, Sidr and Ain Al Faydah in the Al Ain area have the highest risk of flash flood, while the wadis of Khuqayrah and Muraykhat in the eastern mountain ranges have the lowest risk of flash flooding. They calculated the average annual runoff as 1.96 million m3/year in Al Ain basins and 13.78 million m3/year in the eastern-mountain basins. Extreme rainfall variability can cause droughts or floods and makes it difficult even for advanced countries to deal with. Dougherty et al. (2009) have supplied archeological evidence linking abandonment of several cities in the past to severe droughts and a sharp decline of available water resources. The UAE has invested in building over 130 groundwater recharge dams with a storage capacity of about 120 Mm3 across the country. These dams are designed to divert a good part of surface runoff into surface reservoirs and underlying aquifers. But, as temperatures rise and rainfall decreases, surface water reserves will be increasingly at risk and groundwater recharge will almost diminish.

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167

4.10.3  Shortage of Irrigation Water During the last thirty years, a massive program of greening the desert was launched in the UAE, targeting plantation of over 120 million palms trees in the Emirate of Abu Dhabi, UAE. Some of these trees were planted in cities, public parks and gardens, providing a more pleasant quality of life. The program has an important cultural value for the UAE and the Abu Dhabi Emirate in particular, accordingly large areas along UAE borders and major deserts roads were planted to increase the green cover in the country. However, the climate change has represented a great challenge to the newly planted forests, leading to extinction of less tolerant species and changing the habitat in more tolerant ones. The Abu Dhabi Municipality Agriculture Department estimated the amount irrigation water required for the forestry, farms, parks and roadside gardens at 64 million m3/d (Dougherty et al. 2009). During the period 1976–1981, the UAE cooperated with world class experts to choose irrigation technologies that suit the prevailing climatic conditions in the country. After years of research, it was found that drip irrigation is the most suitable method for irrigation of vegetable crops and forest trees. The sprinkler irrigation method is the best for irrigation of forage crops. The bubble irrigation method is the best for irrigation of date palms, fruit and ornamental trees (Rizk and Alsharhan 2008). Climate change represents the main challenge to the growth of the agricultural sector and the greening-the-desert program in the UAE, and conflicts with water conservation plans. One feasible solution to forests irrigation and maintenance is the wide application of treated wastewater for irrigation purposes. On a global scale, Döll (2002) studied the impact of changing climate on the water requirements for irrigation and estimated the increase in water needed for crop irrigation at 5–8% in 2070, with more than a 15% increase in southeast Asia.

4.10.4  Depletion of Groundwater Comparison of annual aquifer recharge to annual groundwater discharge reveals that most the UAE aquifers are experiencing over-exploitation and depletion problems. Most of the groundwater pumped from these aquifers comes from aquifers’ storage, which is not compensated through recharge, due to the prevailing arid climate (Alsharhan et al. 2001). Aquifers recharge in the UAE is limited to the eastern mountain ranges and alluvial gravels at their foothills. The natural aquifers recharge in the UAE is estimated at 120  Mm3 (Khalifa 1995), while the groundwater pumping by the agricultural sector is only 1000 Mm3 (Rizk et al. 1997). This unbalanced situation has led to a sharp decline in hydraulic heads and deterioration of groundwater quality in most water-well fields as a result of saline-water intrusion from various sources.

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Aquifer depletion has resulted in cones-of-depressions of diameters 50 and 100 km, in Al Dhaid and Al Shuaib, respectively. The countries experiencing large water deficits problem have to augment their water resources through aquifer storage and recovery (ASR) approach or wider application of desalinated water, with an ultimate goal of reaching a balance between supply and demand. Rizk (2015) indicated that the reduction of average annual groundwater abstraction from the Wadi Al Bih limestone aquifer decreased from 9  Mm3 during the period 1991–1995 to 4.5  Mm3 during the period 2010–2014. The decrease in groundwater pumping from the aquifer, along with reliance on desalinated water produced by Al Burayrat, Al Humraniah, Rafaq, Ghalilah and Al Nakheel plants, has eased the pressure of depleting groundwater resources, causing an increase of groundwater storage, a rise of hydraulic heads by 1 m in Al Burayrat area and 16 m near Wadi Al Bih main dam and a decrease in average groundwater salinity by 30% in Wadi Al Bih well fields and 40% in the Al Burayrat well field. Postel (1999) called for behavioral changes in groundwater exploitation and irrigation techniques to avoid water shortage and soil degradation. ADEA (2006) contributed 18% of groundwater wastage to unsustainable development of depleting aquifer systems. To bridge the gap between water supply and demand, real efforts are needed to slow down the population growth, improve efficiency of water use and expand the usage of advanced irrigation techniques. In fact, over 90% of irrigated areas in the UAE now apply advanced irrigation methods (MOEW 2015).

4.10.5  Increase of Soil Salinity As temperatures increase, salts accumulate in the soil, reducing its productivity. In hot and dry climates, high evapotranspiration rates increase salinity, which requires the application of additional water to maintain soil productivity. Water evaporation leads to the accumulation of salt that remains on the soil surface, threatening soils and crops alike. Increasing soil salinity threatens the increased crop productivity achieved by the application of modern irrigation techniques. The additional rise in groundwater salinity results from infiltration of agricultural drainage water under heavily irrigated areas. The solution to this problem can be achieved by the installation of drainage systems along with the establishment of an irrigation infrastructure. In addition, there should be careful and proper handling of the hypersaline drainage water, without releasing this water to the sea because of its negative environmental impacts on the marine ecosystems in coastal areas. Dougherty et al. (2009) described mechanisms for reduction of irrigation drainage, including the use of advanced irrigation technologies, improvement of system performance and reuse of drainage water for irrigation of salt-tolerant plants.

4.12 Modeling Climate Change

169

4.11  I mpact of Climate Change on Water-Resources Planning Global climate models have several sources of uncertainty, such as atmospheric conditions and emissions of greenhouse gases. Wide variability in rainfall patterns in space and time is real and has been monitored and reported in several areas during the last two decades. But, uncertainty remained surrounding the degree of severity and impact on the other water sources. IPCC (2008) indicated that water use generally increases with increasing temperature and decreasing precipitation. But, no long-term climate-related water use trends were recorded in the past, mainly because the water usage is mainly driven by factors not directly climate related. In addition, the past records of water-use data are poor in general, in particular time-series data. Population growth, changing societal views on the value of water, economic development, increasing temperatures and decreasing precipitation are among the main stress factors acting on limited, available groundwater resources in various aquifer systems in the country. The social view of the value of water refers to the prioritization of water supplies for industrial and domestic purposes over irrigation water supply and the efficient use of water, including the wide application of water-­ saving irrigation technologies and water tariff. Management of agricultural water demand is the most important element in integrated water-resources management because agriculture, and irrigation in particular, is the main consumer of water on Earth. Postel (1999) indicated that sustainable water- management strategies revolve around how water is allocated and how irrigation is managed. Natural hazards, such as tropical storms, are of particular concern if and when the majority of water supply for domestic uses depends on desalinated water. Desalination plants are easily sabotaged and attacked (Bullock and Darwish 1993). Tropical storms are worth further research by water planners, and circulation in the Arabian Gulf is linked to the ENSO events that may directly affect the UAE. Risks facing desalination facilities, whether from cyclones or oil spills, are worth investment in making the strategic water reserve safer from these hazards.

4.12  Modeling Climate Change A detailed climate change modeling study for the Emirate of Abu Dhabi assumed three main scenarios modeled over the 1961–1990 pre-development conditions. The three scenarios are: the optimistic climate change scenario models where a 1.7 °C warming through 2050 and a 10% increase in precipitation; the pessimistic scenario models assumed 2.7 °C warming through 2050 and a 20% decrease in precipitation;

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4  Climate Conditions and Their Impact on Water Resources 250

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Pressimistic

MOR

Optimistic

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Linear (MOR)

Linear (Optimistic)

Fig. 4.23  Total annual precipitation of the three climate change scenarios for the Abu Dhabi Emirate. (After Dougherty et al. 2009)

20000 18000

1) Optimistic

16000

1.1) Optimistic Adaptation

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2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038 2040 2042 2044 2046 2048

8000

Fig. 4.24  The future annual water demand for the Emirate of Abu Dhabi under various scenarios during the period 2000–2025. (After Dougherty et al. 2009)

while the middle of the road (MOR) scenario models considered 2.2 °C warming through 2050 and a 5% increase in precipitation. Figure 4.23 shows the precipitation trends for all scenarios.

4.12.1  Water Demand Figure 4.24 shows that the total annual water demand ranged from a low about 4000 million m3 for the optimistic scenario with adaptation (2.1) to >18,000 million m3 for the reference scenario.

4.12 Modeling Climate Change

171

Population growth, per -capita water use and agricultural water-use patterns remained at current levels throughout the simulation period. While the reference scenario suggests an upper bound on future water needs if there were no policy interventions. The optimistic scenario (1) indicates an overall increase on water demand, driven by the needs of the industrial and municipal sectors (I and M), as well as population growth. Results show that future water demand in the Emirate of Abu Dhabi will increase by 5000 Mm3 per year in order to meet the needs of 7 million occupants in 2025. The optimistic scenario with adaptation (1.1) saves more than 1000 Mm3 in agricultural uses over optimistic scenarios without adaptation. Results also showed that, even with substantial population growth, the total future water demand could be kept near present levels. A comparison of the three optimistic scenarios revealed that the effect of social adaptation to decreasing demand is more important than the effect of global warming. Results of simulating the climate change under the three optimistic scenarios show a relatively small rise in water demand of about 3% by 2050 (1.2).

4.12.2  Water Supply There is a need for substantial reduction in the per capita water consumption in Abu Dhabi Emirate in the future. Otherwise, the water demand will only be met by increasing production by desalination plants, while the agricultural water demand would be forced to use more saline groundwater, and possibly treated wastewater. The renewable freshwater groundwater resources in the Al Ain area is far from being sustainable enough to be considered as a main source for freshwater resources of the Abu Dhabi Emirate. While fresh groundwater resources remain constant, desalinated water production reached its present capacity and also remained constant over the simulation period (Fig. 4.25). The brackish groundwater will fall short of meeting the needs of irrigated agriculture in the future, and irrigation requirements can be only met by pumping more saline water. In water evaluation and planning the fresh groundwater supplies were set at 10% of the total groundwater supply. For this reason, fresh groundwater resources remained constant. Otherwise, the groundwater resources in the sand and gravel aquifer in the western region of Abu Dhabi Emirate would already be depleted. According to Dougherty et al. (2009), the fresh groundwater resources could meet 10% of the demand, while the remaining irrigation needs will be met by brackish and saline groundwater resources.

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4500 4000 3500 3000 2500 2000 1500 1000 500 0 2002

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2012

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Desalnized

2027

Reused

Brackish GW

2032

2037

2042

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Fresh GW Saline GW

Fig. 4.25  Water supply allocation of the optimistic scenario with adaptation for the Abu Dhabi Emirate. (After Dougherty et al. 2009)

4.12.3  Groundwater Supplies Groundwater is the main source of water for agricultural sector in the UAE. The optimistic scenario with adaptation (1.1) and the same scenario that assumes no climate change (1.2) are only slightly different, indicating a slight impact of climate change on groundwater resources in Abu Dhabi. Results of the optimistic scenarios (1) showed that the effect of climate change on groundwater resources of Abu Dhabi Emirate is small, and the decrease in groundwater storage is mainly attributed to the high agricultural water demand. In addition, scenarios (1) did not include any reductions in agricultural water demand over the simulation period. Figure 4.26 illustrates the estimates of present average annual water demand for the Emirate of Abu Dhabi for the period 2003–2005, and for four future scenarios, averaged over the period 2045–2050. Comparison of the results of optimistic and pessimistic scenarios pointed out the need for a sharp reduction of the per capita use in the municipal and industrial sectors. The results of the three optimistic scenarios showed increases in water consumption driven by the needs of the industrial and municipal sectors, and pointed to the fact that the reduction in agricultural sector could keep future water use at near the present levels. On the other hand, the pessimistic scenarios showed that, even with sharp reductions in the agricultural water use, future water demand could reach three-fold by 2050, unless strong reductions are achieved in the irrigation water and per capita water use.

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Pess with Adaptation No CC 2.2

Agriculture

Fig. 4.26  The total water demand for the for the Emirate of Abu Dhabi under optimistic and pessimistic scenarios, compared with the simulated current water demands averaged over the period 2003 through 2005. (After Dougherty et al. 2009)

Water pollution of the Arabian Gulf can negatively affect the feed water for desalination plants in the Emirate of Abu Dhabi. It seems that intense human activities in industrial areas, harbors and cities are the main sources of marine pollution in Abu Dhabi Emirate. There are also the areas where desalinated water is most needed for economic and social development. Despite high energy requirements and negative environmental impacts, water desalinization is still economically and technically feasible. However, desalination plants generate reject brines, which threatens marine ecosystem when discharged into the sea near coastal areas. These brines are highly saline, and their temperatures are usually higher than the ambient seawater temperature near disposal sites. In addition, reject brines are usually loaded with residual chemicals used in pre-treatment and post-treatment processes. The effluent from desalination plants is a multi-component waste, with multiple effects on water, sediment and marine organisms. A scenario-based approach has to be adopted by Abu Dhabi Emirate for water management in the face of climate change. This approach is already practiced in Australia (Dessai et al. 2005) and the UK (Arnell 1999; Arnell and Delaney 2006). A second approach to cope with uncertainty, referred to as adaptive management (Stakhiv 1998), involves the increased use of water management measures that are relatively robust to uncertainty. Integrated water-resources management should be an instrument to explore adaptation measures to climate change (IPCC 2008). There is high confidence that adaptation can reduce vulnerability in the short term.

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References ADEA (2006) Marine and coastal environment, sector paper. Abu Dhabi Environment Agency, Abu Dhabi Alrustamani ZA (2014) Impacts of climate change on urban development in the UAE. The case of Dubai. Unpublished M. Sc. Thesis, Faculty of Engineering, United Arab Emirates University, p 151 Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region. The Arabian Gulf and adjoining areas. Elsevier Publishing Company, New  York/ Amsterdam, p 331 Al Shamesi MH (1993) Drainage basins and flash flood hazards in Al Ain area, United Arab Emirates. M. Sc. Thesis, Faculty of Science, UAE University, p 151 Arnell N (1999) Climate change and global water resources. Global Environmental Change 9:S31–S49 Arnell NW, Delaney EK (2006) Adapting to climate change. Public water supply in England and Wales. Clim Chang 78:227–255 Boer B (1997) An introduction to the climate of the UAE. J Arid Environ 35:3–16 Brook GA, Sheen SW (2000) Rainfall in Oman and UAE: cyclicity, influence of the southern Oscillation and what the future may hold. Arab World Geogr 3(2):78–96 Bullock J, Darwish A (1993) Water wars: coming conflicts in the Middle East. Victor Gollancz, London Chow VT, Maidment DR, Mays LW (1988) Applied hydrology. McGraw-Hill, New York, p 572 Dessai S, Lu XF, Risbey JS (2005) On the role of climate scenarios for adaptation planning. Glob Environ Change-Human Policy Dimens 15:87–97 Dincer T, Moory M, Javed ARK (1974) Study of groundwater recharge and movement in shallow and deep aquifers in Saudi Arabia with stable isotopes and salinity data. In: Isotope techniques in groundwater hydrology. Proceedings of a symposium, vol 1. IAEA, Vienna, pp 364–374 Döll P (2002) Impact of climate change and variability on irrigation requirements: a global perspective. Clim Chang 54(3):269–293 Dougherty WW, Fencl A, Elasha BO, Swartz C, Yates D, Fisher J, Klein R (2009) Climate change. Impacts, vulnerability and adaptation coastal zones in the United Arab Emirates, water resources in Abu Dhabi and dryland ecosystems in Abu Dhabi. AED (Environment Agency-­ Abu Dhabi), Abu Dhabi, p 197 Garamoon HK (1996) Hydrogeological and geomorphological studies on the Abu Dhabi  – Al Ain  – Dubai rectangle, United Arab Emirates. Ph. D.  Thesis, Ain Shams University, Cairo, Egypt, p 277 Hejase HAN, Assi AH (2013) Global and diffuse solar radiation in the United Arab Emirates. Int J Environ Sci Dev 4(5):470–474 IPCC (2008) Climate change and water, technical paper of the Intergovernmental Panel on climate change. Available from: http://www.ipcc.ch/pdf/technical-papers/climatechange-water-en.pdf Karl TR, Trenberth KE (2003) Modern global climate change. Science 302(5651):1719–1723 Khalifa AA (1995) Surface water and groundwater resources in UAE: culture and science society. Meeting on Water Balance inn UAE, Dubai, p 12 Ministry of Agriculture and Fisheries (1993) Climatological data, v. 3, 1979–80 to 1991–1992. Department of Soil and Water, MAF, Abu Dhabi, p 443 Ministry of Agriculture and Fisheries (2001) Climatological Data: v. 4, no. 4, 1992–1993 to 1999– 2000. Water and Soil Department, MAF, Dubai MOEW (Ministry of Environment and Water) (2015) State of environment report. MEW, Abu Dhabi, p 36 Murad A, Hussein S, Arman H (2014) Possible impact of climate change on water resources: a case study. Recent Advances in Environment, Ecosystems and Development, Ras Al Khaimah (Wadi Al Bih), pp 122–127

References

175

Ouarda TBMJ, Charron C, Kumar KN, Marpu PR, Ghedira H, Molini A, Khayal (2014) Evolution of the rainfall regime in the United Arab Emirates. J Hydrol 514:258–270 Pielke RA Sr, Adegoke JO, Chase TN, Marshall CH, Matsui T, Niyogi D (2007) A new paradigm for assessing the role of agriculture in the climate system and in climate change. Agric For Meteorol (Special Issue) 132:234–254 Postel S (1999) Pillar of sand. Can the irrigation miracle last? W. W. Norton and Company Ltd, New York, p 313 Rizk ZS (2015) Why Wadi Ab Bih limestone is the most sustainable aquifer in the United Arab Emirates? Int J Sustain Water Environ Syst 7(1):21–28 Rizk ZS, Alsharhan AS (2008) Water resources in the United Arab Emirates. Ithraa Publishing and Distribution, Amman, p 624. (in Arabic) Rizk ZS, Alsharhan AS, Shindo SS (1997) Evaluation of groundwater resources of United Arab Emirates. Proceedings of the Third Gulf Water Conference, Muscat, pp 95–122 Rizk ZS, Garamoon HK, El-Etr HA (1998) Morphometry, surface runoff and flood potential of major drainage basins of Al Ain area, United Arab Emirates. Egypt J Remote Sens Space Sci 1(1):391–412 Stakhiv E (1998) Policy implications of climate change impacts on water resources management. Water Policy 1:159–175 Thornthwaite CW (1948) An approach toward a rational classification of climate. Geogr Rev 38:55–94

Chapter 5

Climatic Water Balance

Abstract This study is a trial to understand the mechanisms of groundwater recharge in the sand dunes and gravel plains, which cover about 80% of the surface area of the UAE. The study indicated that the percentage of runoff from rainfall is 18% in the northern Oman Mountains and 3% in the Jabal Hafit area. In this investigation, 75 sediment samples were collected from dune and interdune areas for grain-size analysis and hydraulic conductivity (K) measurement, which were conducted in the laboratories of the Faculty of Science of UAE University. Infiltration capacities (Ic) were measured at 27 sites during sampling. Monthly values of rainfall and potential evapotranspiration (PET) were used to calculate any water surplus (Ps) in the study area. The results contributed to understanding of hydraulic properties of sand dunes and interdune areas around Al Ain City, Eastern Region of the Abu Dhabi Emirate. Results also showed that about 25% of Ps recharges the western gravel aquifer within the study area. The minimum amount of rainfall that can cause surface runoff is about 90  mm/year in the northern Oman Mountains in the UAE and 70 mm/year in the Jabal Hafit area. The data obtained from studying the hydraulic properties of sand dunes can be used for calibration of numerical models that simulate groundwater flow and solute transport in the Quaternary sand aquifer and in the sand-and-gravel aquifer system.

5.1  Introduction This chapter aims at understanding the role of the sand dunes in aquifer recharge and investigates the origin of inland sabkhas. The study also intends to estimate the volume of flash floods accompanying heavy rainstorms. Grain-size analysis and hydraulic conductivity measurements of collected sediment samples were conducted in the laboratories of the Faculty of Science in the UAE University. Measurements of infiltration rates were carried out, with the use of double-ring infiltrometer, at 27 sites during sampling (Figs. 5.1 and 5.2). © Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_5

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54o

55o

56o

Umm Al Quwain

30oN

30oN

Falaj Al Mualla

Ajman I

R

A

N

Sharjah Dubai

BAHRAIN

Dubai Airport

Dubai

QATAR

GULF OF OMAN

Al Hibab

Abu Dhabi UNITED ARAB EMIRATES

25o S A U D I A R A B I A

20oN

50oE

25o O M A N 20oN

Masfut

60oE

ARABIAN GULF

Al Hayer Abu Dhabi International Airport

Abu Dhabi

OMAN Al Oha Al Ain

UNITED ARAB EMIRATES

Ain Sukhnah

24o

24o

40 km Bida Zayed 54o

55o

Al Wagan

Fig. 5.1  Locations of the detailed study of the hydraulic properties of gravel plains, sand dunes and interdune areas within the Al Ain Region of the Abu Dhabi Emirate

The rainfall–evapotranspiration relationship is continuously changing, depending on the amount of rain and vegetation cover. Climatic water balance also varies in space and time. During rainy seasons, November to February, rainfall exceeds potential evapotranspiration, leading to a water surplus. In dry seasons, late March to August, potential evapotranspiration greatly exceeds rainfall throughout the study area, causing a water deficit. When potential evapotranspiration exceeds rainfall and the actual evapotranspiration is known, water deficiency and soil moisture can be estimated graphically. In contrast, when rainfall exceeds potential evapotranspiration, excess water will first be used to saturate the soil through infiltration and the remaining fraction will be a water surplus, which will be lost from the soil through surface runoff and deep percolation. These two processes may occur simultaneously depending upon the soil-infiltration rate. February and March water surpluses at eight meteorological stations were calculated for the period 1971–1992 (Figs. 5.3 and 5.4). These figures show that, although the eastern and northeastern parts of the study area received a water surplus, the western and southwestern parts suffered a water deficit.

5.1 Introduction

179

AL-AIN REGION

55o 30’

24o 30’

Suweyhan 20

11 6

Northern Oman Mountains

Al Hayer

10

3

5 4

19 16 18

9

17

Al Ain 8 12

15

13 21

14

22

23 24 24o 00’

UNITED ARAB EMIRATES

24o 30’

25

OMAN 29

Town

28

Sand sampling site 25

Infiltration test site Main road

Al Wagan

20 km

55o 30’

Fig. 5.2  Locations of sand samples collected for grain-size analysis (open circles), and locations of infiltration measurements (black triangles), within the Al Ain Region of the Abu Dhabi Emirate

Iso-water surplus contour maps were constructed by interpolating the rainfall minus potential evapotranspiration, and the water surplus over the study area was determined using Theissen polygon network (Chow et al. 1988). The zero lines connect points at which the monthly values of rainfall and potential evapotranspiration are equal. The shaded zones represent areas suffering from water deficiency, i.e., in which months evapotranspiration exceeds rainfall. Dashed lines represent iso-water surplus contours, which show a gradual increase towards the east and northeast of the study area. Parts of the calculated water surpluses can replenish groundwater in the Quaternary sand-and-gravel aquifer system within the study area (Figs. 5.5 and 5.6).

54°

55°

56°

Umm Al Quwain

N

Ajman

ARABIAN

Sharjah

GULF

Dubai

20 km

50

26°

Zero Line

26°

O M A N 25

Abu Dhabi

Al Ain

24°

24°

UNITED ARAB EMIR ATE S

54°

55°

56°

Fig. 5.3  Contour map showing lines of equal water surplus (in mm), in the Al Ain area during February 1976. Contour line zero connects points of equal rainfall and evapotranspiration. The shaded area suffers from a water deficit. (After Rizk et al. 1998) 54°

55°

56°

Umm Al Quwain

Ajman

N

Sharjah

ARABIAN

Dubai

GULF

50

20 km

75 26°

25

26°

Zero Line

Abu Dhabi

OMAN

Al Ain

U N I T E D A R A B E M I RATE S

24°

54°

55°

24°

56°

Fig. 5.4  Contour map showing lines of equal water surplus (in mm) in the Al Ain area during February 1982. Contour line zero connects points of equal rainfall and evaporation. The shaded area suffers from a water deficit. (After Rizk et al. 1998)

5.1 Introduction

181

54°

55°

56°

Umm Al Quwain

Ajman

N

Sharjah

GULF

0 10

ARABIAN

Dubai

75

20 km

26°

26°

Abu Dhabi

OMAN

50

Al Ain

UNITED ARAB EMIR ATES

24°

54°

75

24°

55°

56°

Fig. 5.5  Contour map showing lines of equal water surplus (in mm) in the Al Ain area during March 1982. (After Rizk et al. 1998)

54°

55°

56°

Umm Al Quwain

N

Ajman Sharjah

150

175

Dubai

GULF

5

12

ARABIAN

20 km

26°

26°

0 10 75

Abu Dhabi

OMAN

50

25

U N I T E D ARAB E MI RATE S

Al Ain

24°

24°

54°

55°

56°

Fig. 5.6  Contour map showing lines of equal water surplus (in mm), in the Al Ain area during February 1988. (After Rizk et al. 1998)

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5  Climatic Water Balance

5.2  Groundwater Recharge The groundwater table fluctuates in response to several factors. In this study, however, interest is only in water-table fluctuations resulting from the change in groundwater storage. As the prevailing climate in the UAE is arid, the mean annual potential evapotranspiration is much greater than the mean annual rainfall. This does not mean there are no monthly and daily water surpluses associated with occasional heavy rainstorms leading to water surplus, a part of which recharges the groundwater. Groundwater hydrographs are constructed by plotting depths to groundwater versus time at observation wells. The relationship between mean annual rainfall and the depth to groundwater in a shallow well during the period 1981–1991 shows a good correlation (Fig. 5.7). This figure also shows a steady decline in the groundwater level north of the Al Ain area during the period 1981–1991. The groundwater recharge (R) for the unconfined Quaternary aquifer in the Al Ain area, according to Boonstra and de Ridder (1981), can be calculated by multiplying the annual water table rise (r) by the aquifer’s specific yield (Sy).

500 8.5

400

300

200

Rainfall (mm/year)

9.0

9.5 Rainfall

Depth to Water Table (m)

Water depth

10

1981

1982

100

1983

1984

1985

1986

1987

1988

1989

1990

1991

0

Time (Years)

Fig. 5.7  Curved line represent depths to groundwater in shallow water wells north of Al Ain City, in meters, and columns represent mean annual rainfall (in mm), north of the Al Ain area during the period 1981–1991. (After Rizk et al. 1998)

5.2  Groundwater Recharge

183

-8.5 R = r (Sy)

Depth to Water Table (m)

r 1982

-9.0 r1988

r1989

-9.5

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

Time (Years)

Fig. 5.8  Calculation of groundwater recharge, in meters, in the Quaternary aquifer at Al Ain in the Eastern Region of the Abu Dhabi Emirate, with the use of hydrographs of shallow water wells. (After Rizk et al. 1998)

Taking the (Sy) for sandy-gravel aquifers as 5% (Domenico and Schwartz 1990), groundwater recharge for the Quaternary aquifer in Al Ain area can be estimated by the following relationship (Fig. 5.8):

R = r ( Sy )

(5.1)

Where R = the groundwater recharge [m]; r = the water table rise [m]; and Sy = the aquifer’s specific yield [dimensionless]. A plot of the annual groundwater recharge (R) calculated by Eq. (5.1) for a shallow well north of the Al Ain area versus mean annual rainfall during the 1981–1991 period gave a straight line that intersects the rainfall axis at a point (Fig. 5.9). Below this point (rainfall = 140 mm), no groundwater recharge from rainfall is expected, and above it (rainfall >140 mm) groundwater recharge from rain is predicted. An overall fall in the level of the water table between 1981 and 1991 indicates that the consumption of natural water resources exceeds replenishment (Figs. 5.7 and 5.8). This trend deserves serious consideration in future water- resources management.

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5  Climatic Water Balance

40

Correlation Coefficient = 0.97

7. 76 –1 X 0. 16 = Y

Recharge (mm/year)

30

20

10

Groundwater Recharge

No Groundwater Recharge

0

0

50

100

150

200

250

300

350

400

Rainfall (mm/year)

Fig. 5.9  Mean annual rainfall (in mm) versus groundwater recharge (mm/year) relationship for the Quaternary aquifer in the Al Ain area in the Eastern Region of the Abu Dhabi Emirate. (After Rizk et al. 1998)

5.3  Hydraulic Conductivity Seventy-five (75) sediment samples were collected for calculation of hydraulic conductivity of sand dunes during 1994 and 1995. Figure 5.2 shows the locations of sampling and measurement of infiltration rates. The grain-size distribution and uniformity coefficient (Cu) have a great influence on the capacity of sands to transmit fluids. For analysis of grain-size distribution, disaggregated samples are passed through a series of sieves according to the procedures mentioned by Driscoll (1986). The sieves are mounted on a ro-tap shaker that vibrates both vertically and horizontally for a certain length of time (10–15 min per sample). The cumulative weight of particles caught on each sieve is then plotted as a percentage of the total sample weight against grain size in millimeters (Fig.  5.10). Table 5.1 shows the values of effective grain size (d50), uniformity coefficient (Cu) and hydraulic conductivity (K), as determined with the use of Fig. 5.10. According to Taylor (1948), the hydraulic conductivity (K) of sediments depends on the grain diameter. In other words, the size of the soil particles such that 10% are finer by weight governs the sediment’s hydraulic conductivity. For fairly uniform

5.3  Hydraulic Conductivity

185

100

90

80

Cum ula t ive W e ight ( % ) Fine r

70

60

50

40

30

20

LEGEND

10

0 0.01

Sand dunes Gravel plains Interdune areas 0. 1

1

10

Grain Size (mm) Fig. 5.10  Results of grain size analysis of gravel and sand samples from the Al Ain Region of the Abu Dhabi Emirate. (After Rizk et al. 1998)

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5  Climatic Water Balance

loose sand, Taylor (1948) determined the hydraulic conductivity (K) according to the following relation:

K = C( d10 ) 2

(5.2)

Where K = the hydraulic conductivity [cm/min], C = a constant, and d10 = the size [mm] indicating that 10% of the total sample is finer by weight. Taylor (1948) mentioned that the average value of (C) can be taken as 850 for sand samples with uniformity coefficient (Cu) less than five and effective grain sizes (d10) between 0.1 and 0.3 mm. Because the samples collected from sand dunes and interdune areas around Al Ain City lie within the specified Cu and d10 ranges, Eq. (5.2) was applied for calculation of their hydraulic conductivities (K). These were found to vary between 0.5 (mm/min) and 13.3 (mm/min). The hydraulic conductivity (K) of sand dunes in Al Oha, Suweyhan and Al Wagan, were 8.9, 9.5 and 11.1 mm/min, respectively. These values are double to triple the hydraulic conductivities of sand deposits in interdune areas at these sites (Fig. 5.11). This property is extremely important for interdune areas, which are predominantly agricultural regions, in which the soil should retain water for a longer period so that plants can utilize it. The average values of hydraulic conductivity of sediment samples from the Al Ain area measured with falling-head permeameter is 9.8 mm/min in sand dune areas and 2.8 mm/min in interdune areas. These results confirm the calculations of hydraulic conductivity based on grain size-analysis.

5.4  Infiltration Capacity Infiltration means the passage of liquid through a soil or a porous rock. The ­infiltration rate is the rate at which water actually enters the soil surface per unit of time and is frequently determined by comparison with the rate at which the rainfall can be absorbed (Linsley et al. 1992). Infiltration capacity (Ic), as defined by Horton (1945), is the largest possible infiltration rate (Ir) at which a given soil under a given condition can absorb all the rainwater as it falls. The actual infiltration rate is less than the measured infiltration rate, depending on the nature of the soil surface, amount of water available at the soil surface and ability of the soil to conduct infiltration water away from the soil surface. This ability depends on the size of voids, number and interconnection of voids, and potential change in void size due to swelling of clay minerals on wetting. The infiltration rate commonly decreases with the lapse of time because the saturation of soil reduces

5.4  Infiltration Capacity

187

Sand dunes Interdune areas and gravel plains

30

Infiltration Rate (mm/min)

7

8 1

20

29 12 5

6 28 10

10

2 14 23

20 3 21 4

0 0

15

30

45

60

Time (min)

Fig. 5.11  Results of infiltration test experiments in gravel plains, sand dunes and interdune areas in the Al Ain Region of the Abu Dhabi Emirate. Sampling locations are illustrated on Fig. 5.2. (After Rizk et al. 1998)

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5  Climatic Water Balance

Table 5.1  Uniformity coefficient (Cu), hydraulic conductivity (K) and infiltration capacity (Ic) of sand dunes and interdune areas in the Al Ain Region of the Abu Dhabi Emirate No. Location 1 S. Al-Wagan 2 Al-Wagan 3 Al-Oha 4 Al-Oha 5 N. Al-Oha 6 N. Al-Oha 8 Al-Khaznah 9 Al-Saad 10 N. Al-Oha 11 N. Al-Oha 12 Zakher 13 Zakher 15 S. Al-Yahar 16 N. Al-Yahar 17 N. Al-Yahar 18 Al-Saad 19 Al-Saad 20 Suwehan 21 Al-Jaww Plain 22 Al-Jaww Plain 23 Ain Sukhana 24 Al-Wagan Road 25 Al-Wagan Road 26 Al-Wagan 27 Al-Wagan Road 28 Al-Okeir 29 Al-Arrad Maximum Minimum Average

Area Dune Interdune Gravel Plain Gravel Plain Dune Dune Dune Interdune Dune Interdune Dune Interdune Interdune Dune Interdune Interdune Interdune Interdune Gravel Plain Gravel Plain Interdune Interdune Interdune Interdune Interdune Dune Dune

d10 0.14 0.08 0.05 0.08 0.14 0.11 0.14 0.07 0.12 0.07 0.14 0.06 0.08 0.11 0.07 0.07 0.05 0.06 0.06 0.13 0.07 0.06 0.03 0.07 0.09 0.12 0.15 0.15 0.03 0.09

d50 0.18 0.19 0.04 0.25 0.14 0.19 0.18 0.13 0.16 0.13 0.19 0.14 0.19 0.19 0.19 0.12 0.10 0.12 1.00 0.75 0.18 0.08 0.08 0.13 0.18 0.18 0.19 1.00 0.04 0.21

d60 0.18 0.22 0.50 0.50 0.17 0.20 0.19 0.18 0.19 0.16 0.20 0.17 0.30 0.21 0.30 0.16 0.12 0.11 1.80 1.00 0.20 0.15 0.11 0.17 0.19 0.19 0.20 1.80 0.11 0.30

Cu 1.28 2.75 10.0 7.00 1.31 1.82 1.36 2.57 1.58 2.29 1.43 2.83 3.75 2.00 4.29 2.46 2.40 2.67 30.0 7.70 2.86 2.50 4.40 2.42 2.24 1.58 1.34 30 1.28 4.03

KHazen 1.16 0.38 ------1.10 0.71 1.16 0.29 0.85 0.29 1.16 0.21 0.38 0.65 0.29 0.25 0.15 0.21 ------0.29 0.21 0.04 0.29 0.43 0.85 1.33 1.33 0 0.47

Sample locations are shown on Fig. 5.2 Abbreviations: d10 grain size that is 10% fine by weight [mm] d50 grain size that is 50% fine by weight [mm] d60 grain size that is 60% fine by weight [mm] Cu uniformity coefficient [d60/d10] Ic Infiltration capacity [cm/min] KHazen hydraulic conductivity calculated by Hazen method [cm/min] KF. Head hydraulic conductivity measured by a falling-head permeameter [cm/min]

KF. Head 0.85 0.30 ---------0.79 1.11 ---------1.33 0.10 ---0.76 0.22 0.51 0.19 ---0.23 1.28 0.18 ----0.02 0.29 ----1.16 1.51 1.51 0 0.40

Ic 2.30 0.60 0.27 0.09 1.60 1.20 2.12 0.36 1.02 0.55 1.69 0.57 0.34 0.92 0.23 0.34 0.25 0.38 0.16 0.25 0.40 0.29 0.02 0.31 0.31 1.00 1.60 2.30 0.02 0.71

5.4  Infiltration Capacity

189

the hydraulic gradient near the surface and the swelling of clay minerals causes a reduction in pore size. Table 5.1 describes the nature of the sites where infiltration rates were measured, and Fig. 5.2 shows the locations of these sites. The soil infiltration rates were measured with the use of a double ring infiltrometer, which consists of two cylinders of different diameters, so that one cylinder can be placed inside the other. The inner cylinder has a 35-cm diameter and is called the measuring cylinder, and the outer cylinder has a 54-cm diameter and is called the buffer cylinder. The measuring cylinder is connected through a plastic hose to a large bottle of the same diameter, whereas the outer cylinder is connected to a water tank. The large bottle has a graduated glass tube on one side so that the water-level decline in the inner cylinder can be indirectly measured versus time. A siphon was used to control water flow from the bottle to the measuring cylinder and to prevent water overflow. Immediately before the infiltration measurement, a known volume of water is poured into the inner cylinder to a prespecified level from which measurements were taken. The two cylinders are then filled with water, and as the water level descends, it is measured with time. The infiltration rate (Ir) is calculated by dividing the head loss by the corresponding time. After some time, the infiltration rate (Ir) stabilizes and approaches the saturated hydraulic conductivity of the soil layer (Ks), according to the equation: Ir = Ks. Results show that the infiltration rates of interdune areas vary between 1.6 and 6.0 mm/min, while the infiltration rates of sand dunes in Al Oha (16 mm/min), Suweyhan (21.3 mm/min) and Al Wagan (23.0 mm/min) are three to six times the infiltration rates in the interdune areas at the same locations (Fig. 5.11). For correlating the hydraulic conductivity (K) values determined by different methods, the infiltration capacity (Ic) was plotted against the hydraulic conductivities calculated by the Hazen method and measured by a falling-head permeameter (Fig.  5.12a, b). Correlation coefficients are 0.94 and 0.81 for both relationships, respectively. A good correlation (correlation coefficient = 0.94) also exists between the hydraulic conductivities calculated by the Hazen method (K. Hazen) and those measured by a falling head permeameter (Fig. 5.12c).

190

5  Climatic Water Balance 2.5

K Hazen (cm/min)

2.0

Y = 0.58 x 0.09 Correlation Coefficient = 0.94

1.5 1.0 0.5 0.0 0.0

a 0.5

1.0

1.5

2.0

2.5

Infiltration Capacity (I c ) (cm/min) 2.5

K Hazen (cm/min)

2.0

Y = 0.54 x 0.13 Correlation Coefficient = 0.81

1.5 1.0 0.5 0.0 0.0

b 0.5

1.0

1.5

2.0

2.5

Infiltration Capacity (I c ) (cm/min) 2.5

K Hazen (cm/min)

2.0

Y = 0.86 x 0.08 Correlation Coefficient = 0.94

1.5

1.0 0.5

0.0 0.0

c 0.5

1.0

1.5

2.0

2.5

K F. Head (cm/min)

Fig. 5.12  Comparison of hydraulic conductivities of gravel and sand samples from the Quaternary aquifer in the Al Ain Region of Abu Dhabi, calculated with Hazen method (a), field measurements (b) and laboratory analyses (c). (After Rizk et al. 1998)

References

191

References Boonstra J, de Ridder NA (1981) Numerical modeling of ground-water basins—a user oriented manual. ILRI, Wageningen, p 227 Chow VT, Maidment DR, Mays LW (1988) Applied hydrology. McGraw-Hill, New York, p 572 Domenico PA, Schwartz FW (1990) Physical and chemical hydrogeology. Wiley, New York, p 824 Driscoll FG (1986) Groundwater and wells, 2nd edn. St. Paul, Minnesota Horton RE (1945) Erosional developments of streams and their drainage basins—hydrophysical approach to quantitative morphology. Geol Soc Am Bull 56:275–370 Linsley RK, Franzini JB, Freyberg DL, Tchobanoglous G (1992) Water-resources engineering, 4th edn. McGraw-Hill, New York, p 841 Rizk ZS, Garamoon HK, El-Etr AA (1998) Hydraulic properties of dune and interdune areas around Al-Ain, United Arab Emirates. In: Alsharhan, Glennie, Whittle, Kendall (eds) Proceedings of the international conference on quaternary deserts and climatic change. Balkema, Rotterdam, pp 455–467 Taylor DW (1948) Fundamentals of soil mechanics. Wiley, New York

Part IV

Conventional Water Resources

Section A: Surface Water Conventional water sources in the UAE include: seasonal floods, natural springs, aflaj systems and aquifer systems. Although there are no permanent sources of surface water in the country, seasonal floods in the Eastern Region represent a temporary and rare surface-water source. In addition, a few springs’ discharges of about 3  Mm3/year of warm, sulphur-rich water that is used for recreation and therapy. Aflaj discharge, varying between 10 and 30  Mm3/year, represents 3–10% of the total water used in the UAE. Section A of Part Four provides detailed discussion on seasonal floods including (1) analysis of the rainfall–runoff relationship, estimation of flood water volume and calculation of rainfall amounts that may cause flash floods; (2) classification of dry drainage basins in the Eastern Region of the UAE and their flood potential and (3) definition of flash floods, their hazards, the likelihood in various areas and what to do when a flash flood happens. The Eastern Region witnesses a reasonable number of seasonal floods every year. In the past, the valuable water of these floods was lost into the Gulf of Oman on the east coast, Arabian Gulf in the northwest and desert plains in the west and southwest. The waters of seasonal floods cut roads and destroy farms and houses. But, now, a good part of flood water is harvested by a large number of groundwater-­ recharge dams and barriers that were erected within the main drainage basins. It is estimated that more than 120 Mm3 of flood water are annually harvested by groundwater- recharge dams built within the main drainage basins of the mountainous areas or near their outlets. The drainage basins in the eastern mountain ranges are 70, including 58 basins located within the UAE, and the rest are in Oman. The geology, hydrogeology and hydrochemical characteristics of the permanent springs in the UAE are discussed, and the suitability of springs’ water for irrigation, recreation and therapeutic uses is evaluated. The aflaj systems in the UAE, which provide a limited amount of renewable water, are also discussed. The water of aflaj systems is mainly used for irrigation of

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IV  Conventional Water Resources

palm trees in northern and eastern parts of the country. In this section, the authors highlight aflaj history, origin, design, construction, maintenance, management and water distribution, in addition to their geologic setting, hydrogeologic characteristics, water chemistry, isotope hydrology and suitability of aflaj water for irrigation purposes.

Section B: Groundwater Section B of Part Four discusses the results of investigating the limestone aquifers in the Wadi Al Bih basin, Jabal Hafit and the UAE’s Western Region. The Wadi Al Bih limestone aquifer is the main source of water in the Ras Al Khaimah area. For this reason, hydrogeology, hydrogeochemistry, isotope hydrology and water quality of the aquifer have been studied in detail. Similar investigations were carried out on the Dammam limestone aquifer in Jabal Hafit, and the Dammam, Umm Er Radhuma and Simsima limestone aquifers in western UAE. The Semail Ophiolite in the eastern mountain ranges is an aquifer of low productivity, except in areas where the intensity of jointing, folding, faulting and fracturing increases the aquifer’s productivity. These linear features influence groundwater level, chemistry, quality and use. The groundwater quality in the ophiolite aquifer is good because its matrix is hardly soluble in water. Three structural zones affect the ophiolite aquifer: the Dibba zone, the Wadi Ham line and the Hatta zone. These zones do not only affect groundwater resources but also control the distribution of urban centers, farms, water-well fields and sabkha deposits. The gravel plains bound the eastern mountain ranges on the east and west and constitute the largest fresh, renewable groundwater reserve in the country. These plains contain two aquifers; the eastern gravel aquifer and the western gravel aquifer. The eastern gravel aquifer extends from Dibba in the north to Kalba in the south. Groundwater water in this aquifer is the main source of water used for agricultural, industrial and domestic purposes. The western gravel aquifer extends between Ras Al Khaimah in the north and the Al Ain area in the south. The aquifer covers the area between rock outcrops of the mountains in the east and sand-dune fields in the west. The detailed studies of hydrogeology, hydrogeochemistry and isotope hydrology of the Quaternary sand-dune aquifer revealed the presence of two freshwater mounds, at Liwa and Bu Hasa areas. The striking similarity of hydraulic properties enabled considering the aquifers in both areas as a single aquifer named by the authors the “Liwa Quaternary sand aquifer”. Although sand dunes cover 74% of the total area of the UAE, the Liwa Quaternary sand aquifer is the least studied in the country and needs additional detailed investigation in the future. Investigations of the geology, hydrogeology, hydrogeochemistry and isotope hydrology confirm that the sand and gravel sediments act as a single aquifer system in the UAE. Results showed that sand and gravel experience a hydraulic continuity, and in many areas it is difficult to distinguish between the two aquifers. Results also indicate the presence of three groundwater-flow systems, which affect water chemistry and quality in the aquifer.

Chapter 6

Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Abstract  Rainfall records at eight meteorological stations around Al Ain City indicate that most rain falls during the period between February and March, In addition, there are four- to five-year cycles with above-average rainfall, and the median rainfall in Al Ain is 76.1 mm/year, above which flood peaks are expected and below which drought seasons are predicted. Drainage-basin parameters and rainfall data were used along with the HEC-­ HMS model to estimate the water storage from rainstorms in the reservoirs of the Wadi Al Bih, Wadi Al Tawiyean and Wadi Ham basins, in northeastern UAE.  A group of curves illustrating rainfall–runoff and reservoir storage was developed based on the intensity of rainstorms and their duration. These curves were used to predict surface runoff and water storage in the dam reservoirs of the three wadis under rainstorms of various magnitudes. Because the catchment area of wadi Al Bih is larger than Wadi Tawiyean and Wadi Ham, the volume of surface runoff in wadi Al Bih resulting from the same rainstorm was twice the surface runoff on Wadi Ham and Wadi Tawiyean. Based on an annual average rainfall of 115 mm/year, a weighted average runoff coefficient (%) of 7.63, an average annual runoff depth of 8.77 mm/year and the overland flow and flash-flood risk were calculated for drainage basins in the eastern mountain ranges and Jabal Hafit area. Based on ranking of the calculated bifurcation ratios (Rb) and overland flow velocity, relative infiltration rates (Ir) and flood danger were assigned for each drainage basin. The lowest water volume harvested by these dams reached 2.4 Mm3 during the 1999–2000 season, while the largest amount of water retained by these dams reached 20 Mm3 during the 1994–1995 season. The low water harvest during 2004 and 2005 seasons is related to the dry conditions prevailing during this period or incomplete data covering that period of time.

© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_6

195

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6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

6.1  Introduction The UAE is an arid country lacking surface-water resources such as lakes and permanent streams, but the Northern Oman Mountains (eastern mountain ranges) in the country are dissected by many drainage basins (Hydroconsult 1978). During the rainy season between November and March, these wadis can carry large volumes of floodwater despite being dry most the year (Alsharhan et al. 2001). According to Sherif et al. (2011), during the period 1982–2006, the occurrence of flooding storms was 1.3, 1.7 and 2.5 in Wadi Ham, Wadi Al Bih and Wadi Al Tawiyean, respectively. Rainfall exhibits wide variation in time (Fig. 4.6) and space (Fig. 4.9). But usually, rainfall in northern and northeastern UAE, where most of flood events take place, is higher than the mean annual average, which decreased from 119 mm during the period 1974–2003 to 81 mm during the period 2003–2015, as a result of climate change. Over 130 retention and detention dams have been built across the main wadis in northern UAE to divert substantial portions of flood water downward to recharge groundwater (MOEW 2015). For this reason, dams in the country are called “recharge dams“. Records of maximum water storage in Wadi Ham, Wadi Tawiyean and Wadi Bih during the period 1988–1990 are given in Table 6.1. The mountains in northern and eastern parts of the country are largely composed of hard, massive limestone and impermeable Semial ophiolites, allowing infiltration of a small part of the rainwater in these areas, but the main part of flood water reaches the eastern and western gravel plains as runoff. The amount of water lost is directly proportional to rainfall intensity and duration. The Ministry of Climate Change and Environment installed runoff gauges in major wadis to measure flood volumes (Photos 6.1, 6.2, and 6.3). Studies carried out by the authors (Rizk et al. 1997; Rizk and Alsharhan 2008) indicate that the Western Region of the country is characterized by severe drought, a lack of vegetation and an absence of flood events, despite high porosity and hydraulic conductivity of the sand dunes dominating the area. The main reason comes down to scarcity of rain (mean annual rainfall ≈ 40 mm) and high evaporation rates (2000–3000 mm per year). Satellite images, aerial photographs and topographic maps identify the presence of 70 drainage basins in mountain ranges in northern and eastern parts of the country (Al Shamesi 1993); 58 of these basins are located within the UAE. The basins’ Table 6.1  Maximum water storage in dam reservoirs in Wadi Al Bih, Wadi Tawiyean and Wadi Ham in northeastern UAE Wadi Bih Tawiyean Ham

Maximum Elevation (m) 2087 1527 1109

After Sherif et al. (2011)

Catchment area (km2) 195 198 483

Maximum Storage (Mm3) 6.50 3.50 4.87

Date July 1998 March 1998 March 1990

6.1 Introduction

197

Photo 6.1  V-notch weir used for measuring volumes of surface runoff in small streams, fixed in Wadi Siji, Fujairah Emirate

Photo 6.2  Flood-recording device fixed in Wadi Siji, Fujairah Emirate

area varies between 5 km2 (Wadi Dednah in Fujairah Emirate) and 475 km2 (Wadi Al Bih in Ras Al Khaimah Emirate). Figure 6.1 shows the major drainage basins and their catchment areas (Rizk and Alsharhan 2003). Some wadis in large basins may experience more than one flood every year, such as Wadi Shawkah in Ras Al

198

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Photo 6.3  Flood-recording device fixed in Wadi Al Bih, Ras Al Khaimah Emirate

Fig. 6.1  The major drainage basins in northern United Arab Emirates and their catchment areas, based on data from the Ministry of Climate Change and Environment. (After Alsharhan et al. 2001; Rizk and Alsharhan 2003)

Khaimah (Photo 6.4), while others experience a single flood event per year such as Wadi Ham in Fujairah (Photo 6.5). Some wadis, however, have a flood every several years. The estimated annual contribution of flood water to the total water resources in the UAE, according to the estimates of the MAF in 1993 (now: Ministry of Climate Change and Environment), is 120 Mm3. For this reason, the Ministry has already built 113 dams and a barrier until the beginning of 2007, with total storage capacity of more than 125  Mm3 (MOEW 2015) and more than 20 dams were built after that date. In addition to their main role in groundwater recharge, dams protect farms, roads, houses and facilities against the risk of flash floods.

6.1 Introduction

199

Photo 6.4  Reservoir of Wadi Shawkah Dam, Ras Al Khaimah Emirate. The reservoir is almost full throughout the year because it receives flood waves more than once a year during winter and summer. This image shows the reservoir after a flood in November 2004

Photo 6.5  Reservoir of Wadi Ham Dam, Fujairah Emirate. The reservoir catches runoff water during rainy years, remaining dry in years with low mean annual rainfall

200

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

6.2  Morphometry There are two drainage patterns in the Eastern Region; one in the eastern mountain ranges, and the other in Jabal Hafit area, south of Al Ain City (Fig. 6.2). The dendritic drainage pattern dominates the mountains, which consist mainly of massive and homogeneous igneous and metamorphic rocks. Parallel and rectangular drainage patterns are common in areas affected by joints, folds, faults and fractures. Subradial drainage pattern characterizes Jabal Hafit’s plunging anticline and prevailing braided pattern in Al Jaww alluvial plain, which has a flat surface with a gentle slope from east to west. The morphometric analysis of the main drainage basins in the Al Ain area, conducted by Al Shamsi (1993), was used by the authors to predict surface runoff and flood potential in this region. The morphometric parameters used are the bifurcation ratio (Rb), drainage density (Dd) and stream frequency (Fs). Surface runoff is also affected by drainage elevations, slope and shape. Garamoon (1996) studied the morphometric parameters of drainage basins in the northern Oman Mountains and Jabal Hafit area (Fig. 6.3). According to White et al. (1992), the bifurcation ratio (Rb) values usually varies between 2 and 5. The Rb values of drainage basins in the eastern mountain ranges vary between 2.0 (Wadi Sidr) and 5.6 (Wadi Muraykhat), and the Rb of drainage basins in Jabal Hafit ranges from 2.75 (Wadi Al Ashkhar) to 6.65 (Wadi Ain Al Faydah). According McCullagh (1978), drainage basins of large Rb values commonly have reduced flooding risk, while basins with small Rb values are potentially subject to rapid and hazardous floods. Drainage density (Dd) is the result of dividing the total length of all streams in a drainage basin by its total area. The Dd values of drainage basins in eastern mountain ranges vary between 2.5 (Wadi Al Ain) and 1.5 (Wadi Saad), and the Dd of drainage basins in Jabal Hafit ranges from 3.2 (Wadi Tarabat) to 1.6 (Wadi Milehah). Basins with large drainage density (Dd), such as Wadi Al Ain and Wadi Tarabat, have a large runoff velocity because both basins have short paths of overland flow. On contrary, runoff potential is low in drainage basins such as Wadi Milehah, which has low Dd, a long path of overland flow, large underflow and large infiltration rates. Stream frequency (Fs) is represented by the number of streams per unit area. Drainage frequency of basins in the eastern mountain ranges varies between 0.5 (Wadi Sidr) and 1.27 (Wadi Al Ain), and the Fs of basins in Jabal Hafit ranges from 0.7 (Wadi Ain Al Faydah) to 1.3 (Wadi Tarabat). According to drainage frequency, a maximum flood is predicted to occur through Wadi Sidr (Fs = 0.5) and a minimum flood in Wadi Tarabat (Fs = 1.30). The large gradient streams have low runoff-residence time and a high potential for flash flooding. The relief of drainage basins depends on the ruggedness number, relief ratio and gradient. The relief of drainage basins in the eastern mountain ranges varies between 100 (Wadi Bu Qalah, Wadi Sidr, and Wadi Muraykhat) and 800 (Wadi Ghayl and Wadi Ajran), and the relief of drainage basins in Jabal Hafit ranges from 300 (Wadi Tarabat and Wadi Ain Al Faydah) to 800 (Wadi Al Ashkhar).

6.2 Morphometry

201

56o

26o

26o

Shaam

ARABIAN

1

GULF

2

GULF OF OMAN

OMAN 18

Ras Al Khaimah

3 Diba

Umm Al Quwain 4

Ajman

6

14 24

7

Khor Fakkan

27

Water Divide

17

9 10

UNITED ARAB EMIRATES

Fujairah

22

16 25o

13

5

Sharjah Dubai

19

Kalba

15

8

25o

12 23

OMAN

20 km 56o

Fig. 6.2  The main drainage basins in the northeastern mountain ranges in the United Arab Emirates, traced from topographic maps and Landsat Satellite images. (After Alsharhan et  al. 2001; Rizk and Alsharhan 2003)

202

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

55o 50’

55o 40’

56o 00’

Oman Mountains Basins 1 Ajran Muraykhat 2 3 Thuqbat Saah Mudabbah 4 5 Lihsat 6 Shik 7 Ghayl 8 Musayliq Sidr 9 10 Masah 11 Bu Qalah 12 Khubayb 13 Khuqayrah 14 Saad 15 Al Ain

1 2 3 4 5

Jabal Hafit Basins Al Ain Tarabat Ain Al Faydah Al Ashkhar Mileha

56o 10’

14 13

24o 30’

12 11 10 8

9

24o 20’

15 7

1

Jabal Hafit

Al Jaww Plain

2

5

24o 10’

4

3 3 4

55o 40’

Oman Mountains

6

5

2 55o 50’

56o 00’

1

8 km

24o 00’

Fig. 6.3  Dry drainage basins in the eastern mountain ranges and Jabal Hafit, separated by the Al Jaww plain in the Al Ain area, Eastern Region of the United Arab Emirates. (After Rizk et al. 1998; Rizk and Alsharhan 2003)

The values of circularity, elongation and shape index of drainage basins in the eastern mountain ranges and Jabal Hafit show that Wadi Shik and Wadi Al Ain are circular; Wadi Ajran and Wadi Muraykhat are elongated; and Wadi Musayliq and Wadi Al Ashkhar are triangular. The circular drainage basins have the shortest runoff distance and are the most conducive for flash flooding. But, the shape of the basin is not the only factor determining floods and is not dealt with separately. The elongated basins with large (Rb) values commonly have a low flood potential, whereas circular basins with small (Rb) values have high flood potential (Patton 1988).

6.4  Rainfall–Runoff Relationship

203

Rizk and Garamoon (2006) studied the morphometry of Al Dhaid superbasin (1525 km2) and its sub-basins: the wadis of Al Dhaid, Kadrah, Shawkah, Hamdah and Meleiha. The catchment area of each sub-basin was outlined, traced and measured with the use of a planimeter. Then, the drainage lineation map of the Al Dhaid Super Basin was prepared with the use of topographic sheets of various scales (Fig. 10.3). The stream numbers in each order were counted and recorded in Table 10.1, for the calculation of the bifurcation ratio (Rb), drainage density (Dd) and stream frequency (Fs).

6.3  Surface Runoff Surface runoff is the overland flow across the ground surface to the nearest channel (Linsley 1992), and rainfall intensity is the amount of rainfall in a specific amount of time, while the average length of overland flow equals 1/(2Dd), where (Dd) the drainage density is the result of dividing the total length of all stream segments in a drainage basin by its total area (Horton 1945). Thus, if Dd is low, overland flow will be low and long, and a small amount of water will be transported into wadi channels. In this case, rainwater will take more time to infiltrate, thus contributing more to groundwater recharge. Therefore, the contribution of flood water to groundwater recharge becomes more efficient. Flood records in the Western Region of the UAE are few or absent, and most of flood measurements were conducted by the MAF in the past (1993–1999), or are being conducted by the MOCCAE in the present. Examples of these records are listed in Tables 6.2 and 6.3) and illustrated on Figs. 6.4, 6.5, 6.6, and 6.7).

6.4  Rainfall–Runoff Relationship Rizk et al. (1998) used satellite images and topographic maps, in addition to records of flood gauging stations and meteorological stations, to estimate the surface-runoff volume and for assessment of flash-flooding potential on major wadis in the Eastern Region of Abu Dhabi Emirate (Fig. 6.2). These data were used to calculate the average annual runoff (Mm3), runoff depth (mm) and rainfall–runoff relationship for some wadis during the period 1981–1990 (Tables 6.2 and 6.3). From these tables and figures, the weighted annual average runoff in the Eastern Region of the UAE varies between 7.63 and 11.20% of the average annual rainfall, in the Al Ain area and the eastern mountain ranges, respectively. The calculated runoff volumes (Mm3) versus average annual rainfall (mm) and drainage area (km2) for five drainage basins in eastern UAE, including Wadi Sifuni in the northeastern UAE and Wadi Shik in the central part, are presented in Figs. 6.8, 6.9, 6.10, and 6.11). The calculated flood volumes were also plotted versus average annual rainfall in both basins (Figs.  6.12 and 6.13). Both figures show that the

No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Physiographic Factor Catchment area (km2) Average width (km) Average length (km) Basin length along main stream (km) Perimeter (km) Perimeter of equivalent circle (km) Shape index Form factor Rotundity factor Compactness coefficient Elevation at the dam site (mamsl) Maximum elevation (m amsl) Average elevation (mamsl) Maximum relief (m) Average slope Time of concentration (min) Number of streams Stream density Length of main stream (km) Total length of stream (km) Drainage density Runoff coefficient (%)

Hadf 37.5 4.0 7.0 9.0 26.5 18.2 2.2 0.5 1.2 1.5 400 1311 855 911 7.9 80 62 1.7 11.5 80 2.1 12.0

Shawkah 54 5.1 12 13 34 26 3.1 0.3 2.5 1.3 270 912 591 642 3.9 120 108 2.0 17 120 2.2 10

Ham 90.0 5.0 12.5 15.0 41.0 29.7 2.5 0.4 2.0 1.2 50 1109 580 1059 5.3 124 131 1.5 20.0 149 1.7 8.0

Bih 475 19.3 41.0 43.0 118 77.2 3.9 0.3 3.1 1.5 65 2087 1046 2022 4.4 256 245 0.5 46.5 528 1.1 2.0

Shimal 120 6.3 20.6 21.5 66.5 38.9 3.9 0.3 3.0 1.7 110 1128 619 1018 4.6 141 287 2.4 22.0 237 2.0 14.0

Rumth 30.5 3.5 10.0 10.2 27.5 19.6 3.4 0.3 2.7 1.4 140 1013 577 873 8.3 63 35 1.2 10.5 45 1.5 19.0

Safad 26 4.5 7.0 8.0 22 18 2.5 0.4 1.9 1.2 55 846 451 791 7.5 66 31 1.2 11 39 1.5 19

Farfar 68 7.9 6.0 14 43 29.2 2.9 0.3 2.3 1.5 126 840 483 714 4.0 123 78 1.2 18 114 1.7 15

Gulfa 6.6 2.5 4.5 5.7 14.0 26.4 3.3 0.3 2.6 1.3 450 700 575 250 3.8 30 16 2.4 6.5 22 3.3 15

Shi 17 2.8 5.5 7.0 18 15 2.9 0.4 2.3 1.2 30 807 419 777 10 44 35 2.1 7.5 33 1.9 15

Ghail 6.0 1.6 3.7 5.9 14 8.8 5.8 0.2 4.6 1.6 3 700 509 382 6.3 46 26 4.3 6.0 43 7.2 13

Idhn 61 8.5 6.0 12 40 28 2.6 0.4 2.0 1.4 2 837 529 617 5.0 86 87 1.4 13 110 1.8 10

Madha 94.0 8.8 10.0 11.5 37.0 34.4 1.4 0.7 1.1 1.1 65 1124 595 1059 5.3 124 111 1.2 20.0 141 1.5 12.0

Masfut 76.0 7.2 10.0 18.0 43.0 30.0 1.4 0.4 1.0 1.4 340 1311 826 971 5.4 113 109 1.4 18.0 175 2.3 10.0

Table 6.2  Morphometric parameters of major drainage basins in northern and eastern parts of the United Arab Emirates, based on data obtained from the Ministry of Climate Change and Environment

204 6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

21 22

20

17 18 19

14 15 16

13

12

7 8 9 10 11

5 6

No. 1 2 3 4

Physiographic Factor Catchment area (km2) Average width (km) Average length (km) Basin length along main stream (km) Perimeter (km) Perimeter of equivalent circle (km) Shape index Form factor Rotundity factor Compactness coefficient Elevation at the dam site (mamsl) Maximum elevation (m amsl) Average elevation (mamsl) Maximum relief (m) Average slope Time of concentration (min) Number of streams Stream density Length of main stream (km) Total length of stream (km) Drainage density Runoff coefficient (%)

1.4 0.7 1.1 1.1 50

33.3 29.7

Ghalilah 70 7.0 7.3 10.0

992

1.0 18.0

35

30 0.9 8.0

1.1 16.0

79

40 0.6 12.0

1459 1884 18.0 16.0 38 55

760

1489 1934

1.8 0.5 1.5 1.1 30

23.0 20.0

Sham 35 5.0 5.4 8.0

1.3 18.0

120

91 1.1 16.0

1416 8.9 86

792

1500

2.0 0.5 1.6 1.3 84

44.5 33.1

Naqab 90 7.0 12.3 13.5

1.7 15.0

339

222 1.1 33.0

1392 4.2 199

831

1527

4.0 0.2 3.2 1.7 135

85.0 50.0

Tawiyean 198 7.2 20.0 28.5

2.9 12

169

57 1.0 16

447 2.9 129

379

602

2.1 0.5 1.6 1.2 155

31 27

Mutarid 58 5.6 9.6 11

2.1 12

150

132 1.9 17

607 3.6 127

597

897

2.0 0.5 1.6 1.3 290

39 30

Mawrid 71 7.0 8.0 12

4.1 0.2 3.2 1.4 80

68.0 48.0

Wahala 185 6.3 25.5 27.5

1.6 15.0

138

150 1.7 15.0

894 6.0 95

677

1.7 10.0

320

219 1.2 34.5

967 2.8 241

564

1124 1047

1.8 0.6 1.4 1.1 230

37.5 28.4

Siji 88 6.2 11.6 12.6

1.9 13.0

85

70 1.5 16.0

359 2.2 145

404

583

3.8 0.3 3.0 1.5 225

37.0 24.0

Ashwani 46 3.9 12.5 13.3

2.5 14.0

260

175 1.7 18.5

850 4.5 123

625

1050

2.9 0.3 2.3 1.3 200

47.0 36.5

Sifuni 104 9.0 13.5 17.5

1.7 14.5

366

270 1.3 26.0

850 3.3 184

625

1050

1.9 0.5 1.5 1.2 200

64.0 52.1

Ashwani 216 9.6 10.5 20.0

1.9 15

579

380 1.3 32

691 2.2 251

474

819

2.7 0.4 2.1 1.5 182

92 92

Guor 303 15 16 29

1.7 0.6 1.4 1.3 98

52.0 40.2

Wurrayah 129 11.2 10.7 15.0

527

6.0 15.0

434

295 4.7 21.0

2.3 12.0

301

371 2.9 27.5

1063 858 5.0 3.1 131 194

597

1128 956

1.7 0.6 1.3 1.1 65

34.0 30.2

Zikt 73 7.8 8.7 11.0

6.4  Rainfall–Runoff Relationship 205

206

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Table 6.3  Calculated runoff volume (in Mm3) runoff depth (in mm) and percentage of rainfall as runoff (%), for Wadi Sfini in the eastern mountain ranges of the United Arab Emirates (Area = 216 km2) Annual Rainfall (mm) 101 311 158 24 25 51 163 241 60 183 132

Runoff Volume (Mm3) 0.30 4.46 3.59 – – – 2.02 5.36 – 3.5 1.94

Runoff Depth (mm) 1.4 20.7 16.6 – – – 9.4 24.8 – 16.2 8.9

55o

54o

Rainfall as Runoff (%) 1.4 6.5 10.5 – – – 5.8 10.3 – 8.9 4.4

Umm Al Quwain

N

15

25

20

Ajman Sharjah

30

Year 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Average

Dubai

20 km

GULF 10

ARABIAN

5

25o

Abu Dhabi

OMAN

Al Ain

UNITED ARAB EM IRATES 24o

24o

54o

55o

56o

Fig. 6.4  Contour map of rainfall intensity (in mm), in the eastern mountain ranges of the United Arab Emirates in 1979. (After Rizk et al. 1998)

­ inimum amount of rainfall that can cause surface runoff is about 90 mm/year in m the northeastern part of the UAE (Wadi Sifuni) and 70 mm/year in the central part and Jabal Hafit area (Wadi Shik).

6.4  Rainfall–Runoff Relationship

207

55o

54o

Umm Al Quwain

N

Ajman Sharjah

3.0 0

Dubai 00 2.

GULF 0 0.5

25o

0 1.5

ARABIAN

1.00

20 km

2. 50

5 0.2

Abu Dhabi

OMAN

Al Ain

UNITED ARAB EMIRATES 24o

24o

54o

56o

55o

Fig. 6.5  Contour map of annual runoff volume (Mm3) in the main drainage basins in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998)

54°

55°

56°

Umm Al Quwain

N

Ajman

5

ARABIAN

20 2 0

Dubai 20 km

15

10

Sharjah

GULF

25°

25°

Abu Dhabi

OMAN

UNIT ED ARAB EMIRATES

Al Ain

24°

24°

54°

55°

56°

Fig. 6.6  Contour map of runoff depth, in millimeters, in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998)

208

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

54o

55o

Umm Al Quwain

N

Ajman

15

Dubai

GULF

9

ARABIAN

12

20 km

18

Sharjah

3

6

25o

Abu Dhabi

OMAN

Al Ain

UNITED ARAB EMIRATES

24o

54o

24o

55o

56o

Fig. 6.7  Contour map showing the percentage of rainfall as runoff in the eastern mountain ranges of the United Arab Emirates for the period 1981–1990. (After Rizk et al. 1998)

Fig. 6.8  Relationship between annual rainfall (mm) and runoff depth (mm) for five drainage basins in the eastern mountains of the United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)

6.5  Estimation of Runoff Volume

209

Fig. 6.9  Relationship between annual rainfall (mm) and runoff volume (Mm3) in Wadi Al Shaikh in the eastern mountains of the United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)

Fig. 6.10  Relationship between runoff volume (Mm3) and basin area (km2) for five drainage basins in the eastern mountains of United Arab Emirates for the period 1981–1991. (After Rizk et al. 1998)

6.5  Estimation of Runoff Volume Calculation of runoff volumes of the drainage basins in the Jabal Hafit area and the eastern mountain ranges for the period 1981–1990 can be expressed as a percentage of weighted-average annual runoff. Calculated runoff volumes varied between 0.25 Mm3 in the southwestern part of the Al Ain area and 3.0 Mm3 in the eastern

210

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Fig. 6.11  Relationship between annual rainfall (mm) and runoff volume (Mm3) in Wadi Sfini in the eastern mountains of United Arab Emirates during the period 1981–1991. (After Rizk et al. 1998)

Fig. 6.12  Relationship between the mean annual rainfall (mm) and runoff volume (Mm3) in Wadi Sfini in the eastern mountains of the United Arab Emirates during the period 1981–1991. (After Rizk et al. 1998)

mountain ranges. The calculated runoff percentage of rainfall ranges from 3% in the drainage basins of Jabal Hafit and 18% in the drainage basins of the eastern mountain ranges (Fig. 6.7; Tables 6.4 and 6.5). Based on field measurement of infiltration rates and calculating the length of overland flow, Wadi Muraykhat and Wadi Al Ain in Jabal Hafit area have the lowest

211

6.5  Estimation of Runoff Volume

Fig. 6.13  Relationship between the mean annual rainfall (mm) and runoff volume (Mm3) in Wadi Shik in central UAE for the period 1981–1991. (After Rizk et al. 1998)

Table 6.4  Calculated runoff volume (Mm3), runoff depth and percentage of rainfall as runoff for Wadi Sheikh in the eastern mountain ranges of the United Arab Emirates (Area = 32.8 km2) Year 1982 1983 1984 1985 1986 1987 1988 1989 1990 Average

Annual Rainfall (mm) 241 165 1.20 14.0 52.2 122.7 126.8 85.0 201 112

Runoff Volume (Mm3) 0.53 0.46 – – – 2.02 0.32 – 0.52 0.20

Runoff Depth (mm) 16.2 14.0 – – – 9.40 9.80 – 15.9 6.20

% Rainfall as Runoff 6.7 8.5 – – – 5.8 7.7 – 8.0 3.4

flood potential, while Wadi Al Ain Al Faydah in Jabal Hafit and Wadi Sidr in the eastern mountain ranges in UAE have the highest potential of flash flooding (Fig. 6.13).

212

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Table 6.5  Calculated runoff volume (Mm3), runoff depth (mm) and percentage of rainfall as runoff in some drainage basins in the eastern mountain ranges of the United Arab Emirates for the period (1982–1990) Name of Wadi Wadi Al-Bih Wadi Siji Wadi Guor West Wadi Guor East Wadi Shik

Area (Km2) 474

Average Annual Rainfall (mm) 125

Runoff Volume Runoff Depth % Rainfall as (Mm3) (mm) Runoff 2.00 4.22 3.20

87 –

130 110

1.97 0.48

22.64 –

16.7 –

303

140

5.25

17.38

12.1

32.8

105

0.20

6.10

5.70

6.6  Rainfall-Reservoir Storage Prediction of surface-runoff volumes in catchment areas of arid regions is essential for water-resources planning and management. Garamoon (1996) investigated the climatic water balance characterized by the relationship between rainfall and ­potential evapotranspiration in drainage basins of the eastern mountain ranges and Jabal Hafit. He calculated the monthly values of water surpluses (Ps) during the period 1971–1992 and concluded that the minimum amount of rainfall that can cause surface runoff in the eastern mountain ranges basins as 90 mm/year (Wadi Sifuni) and 70 mm/year in Jabal Hafit basins (Wadi Shik). Sherif et al. (2011) developed a rainfall-runoff model for three drainage basins in northern UAE and established the relationship between the volume of water stored at the three dam reservoirs: Wadi Al Bih, Wadi Tawiyean and Wadi Ham and annual rainfall. Sherif et al. (2011) used the HMS (Hydrologic Modeling Center) program to establish flood and yield hydrographs at the sites of the three dams: Al Bih, Tawiyean and Ham.

6.6.1  Input Data The applied program requires three data sets as input parameters: the basin model, meteorological data and control specifications. The basin model incorporates data on aquifer systems, hydraulic connection, basin geometry and its sub-basins, dam reservoir and sources and sinks. The meteorological data including rainfall and evaporation, in addition to other data required to run with the HEC-HMS model. Sherif et  al. (2011) selected the simulation parameters such as the starting date, the ending date and time step.

6.6  Rainfall-Reservoir Storage

213

6.6.2  Model Calibration Model calibration was performed in several simulations with the use of various data sets on the average number of floods per year, parameters of the three basins and their sub-basins, weights of rain gauge in each basin and the estimated and observed storage in each of the three dam reservoirs. The main purpose of model calibration is to reach the pre-specified tolerance between the measured and simulated storage of all rainstorms for each basin.

6.6.3  Storage Simulation After calibration, the model was used to estimate the storage in the dam reservoirs of the three basins, as well as the cumulative flood volume at the Bithna gauging station of Wadi Ham. The mean rainfall intensity over each catchment was used to estimate the runoff coefficients for each of the three basins. The runoff coefficient varied with rainstorms between 50 and 100 mm (Table 6.6). For higher rainfall intensities, Wadi Ham has higher runoff yield (29%) compared to Wadi Tawiyean (22%) and Wadi Bih (19%). Records of historical rainfall events were used to establish the relationship between rainfall and direct runoff for the three basins (Fig. 6.14). The calibrated model was used for simulating several scenarios of rainstorms over the catchment areas of Wadi Al Bih, Wadi Tawiyean and Wadi Ham and estimating the total volume of runoff water stored in dam reservoirs, in addition to the total volume runoff water at the gauging station of wadi Ham. The simulation results were used to develop curves relating storage to rainfall for various rain storms at the three basins. Figure 6.15 illustrated the curves drawn based on model simulations. As can be seen on these curves, for the same depth of rainfall, the amount of runoff water stored in Wadi Al Bih reservoir is the largest of all the three basins. Given the similar geologic setting of Wadi Tawiyean and Wadi Ham, the volumes of runoff water stored in their dam reservoirs are equal for the same depth of rainfall. Sherif et al. Table 6.6  Calculated runoff volume (Mm3), runoff depth (mm) and percentage of rainfall as runoff in selected drainage basins of Jabal Hafit, south of the Al Ain area Name of Wadi Wadi Al-Ain Wadi Tarabat W. Ain Al-Faydah W. Al-Ashkhar Wadi Milehah

Area (Km2) 76.3 38.5 9.60

Average Annual Rainfall (mm) 115 115 115

Runoff Volume (Mm3) 0.67 0.34 0.08

Runoff Depth (mm) 8.78 8.83 8.30

% Rainfall as Runoff 7.6 7.7 7.2

48.6 57.3

115 115

0.43 0.48

8.85 8.38

7.7 7.3

214

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Fig. 6.14  Model-calculated runoff (mm) versus rainfall depth (mm) for (a) Wadi Ham, (b) Wadi Tawiyean and (c) Wadi Al Bih in northern UAE. (After Sherif et al. 2011)

6.7  Flash Floods

215

Fig. 6.15 Model-­ calculated rainfall-storage relationship for (a) Wadi Ham, (b), Wadi Tawiyean and (c) Wadi Al Bih in the northern part of the UAE. (After Sherif et al. 2011)

(2011) mentioned that the total water volume at Bithna gauging station is about one-­ half of the water stored in Wadi Ham dam reservoir. The curves illustrated in Fig. 6.15 can be used to predict the volumes of water stored in a dam reservoir for various rainfall amounts. The curves illustrating the relationship between rainfall depth and volume of runoff water stored in dam reservoirs of Wadi Al Bih, Wadi Tawiyean and Wadi Ham basins (Fig. 6.15) were verified with the actually measured rainfall depths and water storages of subsequent storms affecting the three basins. Comparisons between observed and simulated runoff volumes stored behind the three dam sites constitute an independent calibration method of confidence and reliability of the developed rainfall–runoff curves. Sherif et al. (2011) used the results of simulating the rainfall-depth–surface- runoff storage relationship illustrated in Fig. 6.14 for the construction of a group of rainfall intensity-duration–direct-runoff curves for Wadi Al Bih, Wadi Tawiyean and Wadi Ham basins (Fig.  6.16). The direct runoff resulting from various rainfall storms of variable duration can be predicted for the three basins with the use of the curves illustrated in Fig. 6.16. These curves cover a wide range of rainfall intensities (0–100 mm/h) and durations (2–50 h) to enable the prediction of runoff volumes associated with a wide range of rainstorms.

6.7  Flash Floods Once rainfall occurs, water first accumulates on the ground as surface retention and then the surface water initiates an overland flow that begins to move down the slope into small rills, which integrate into larger channels, and finally flow as surface runoff to the watershed outlet. The desert areas are characterized by the phenomenon of flash floods, which are usually associated with heavy rainstorms in mountain areas. These areas in UAE are dominated by igneous and metamorphic rocks of low porosity, permeability and hydraulic conductivity, turning the bulk of the rain into surface runoff.

216

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Fig. 6.16  Direct runoff-duration–intensity curve for (a) Wadi Ham, (b) Wadi Tawiyean and (c) Wadi Al Bih in the northern part of the UAE. (After Sharif et al. 2011)

6.7  Flash Floods

217

The water of seasonal floods usually accumulates in mountainous regions, near the water-divide line, and then runs off this line across the eastern coastal plain toward the Gulf of Oman and through the western gravel plans and sand-dune fields towards the Arabian Gulf in the northwest, west and southwest. Flash floods are known as sudden, rapid movements of large quantities of water through drainage channels, resulting from high-intensity rain during a short period of time. Flash floods happen within 6 h of the beginning of a rainstorm. The danger of flash floods is related to the fact that they occur very quickly and surprise people who are not ready for them. The risk of flash floods increases in the absence warning tools and mechanisms. Therefore, one of the objectives of building of a large number of dams and barriers in the eastern mountain ranges of the UAE was for protection against the dangers of flash floods, which had so often destroyed roads and repeatedly flooded homes and farms. The changing the nature of the land resulting from urban expansion increases the likelihood of flash floods by about a factor of six compared to the likelihood if the land had remained unchanged. Although there are a number of factors affecting flash floods, rainfall density and duration are the most important. Topography, soil nature and vegetation cover also play an important role in the occurrence of flash floods. So, people living in areas prone to flash floods have to learn and teach their family members and guide them on how to act in the event of floods, such as avoiding being in a wadi channel during heavy rains, even if the wadi channel had been dry. In this case, heading to a higher area away from water is the right practice. It is also recommended to contact emergency or civil defense when needed.

6.7.1  Flash Floods Hazard Based on an annual average rainfall of 115 mm/year, weighted-average runoff coefficient (%) of 7.63 and average annual runoff depth of 8.77 mm/year, overland flow and flash-flood risk were calculated for drainage basins in the eastern mountain ranges in the UAE and Jabal Hafit area (Tables 6.7 and 6.8). Based on the ranking of the calculated bifurcation ratios (Rb) and overland flow velocity, relative infiltration rates and flood-flash risk were assigned for each drainage basin within the study area (Figs. 6.17, 6.18, and 6.19). Table 6.7  Calculated coefficient of runoff for Wadi Al Bih, Wadi Tawiyean and Wadi Ham basins, from the fitted model Rainfall (mm) 50 75 100 After Sherif et al. (2011)

Calculated Runoff Coefficient (%) Wadi Al Bih Wadi Tawiyean 6 8 14 16 19 22

Wadi Ham 6 20 29

218

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Table 6.8  Predicted average runoff volume (Mm3), overland flow velocity and ranking, according to overland-flow velocity and flood hazard of some drainage basins in northeastern UAE Wadi Name Ajran Muraykhat Saah Mudabbah Lihast Shik Ghayl Musayliq Sidr Masah Bu Qalah Khubayb Khuqayrah Saad Al-Ain

Area (Km2) 98.30 32.50 15.50 67.10 44.10 32.80 18.50 133.7 16.90 17.10 118.7 39.70 84.70 136.3 149.5

Predicted Runoff (Mm3) 0.86 0.29 0.14 0.59 0.39 0.29 0.16 1.17 0.15 0.15 1.04 0.35 0.74 1.19 1.31

Rank of Flash Flood Risk 6.0 8.0 9.0 7.0 10 6.0 5.0 4.0 4.0 4.0 5.0 1.0 3.0 2.0 9.0

Overland Flow Velocity 0.26 0.22 0.20 0.24 0.22 0.26 0.28 0.29 0.29 0.29 0.28 0.36 0.31 0.33 0.20

Rank of Overland Flow 4.0 1.0 8.0 6.0 9.0 10 5.0 7.0 5.0 5.0 9.0 3.0 2.0 8.0 9.0

6.8  Recharge Dams Groundwater-recharge dams in UAE have played a major role in reducing flashflood hazards and protecting homes, roads and farms. The dams have also harvested significant proportions of flood water, diverting most of it towards groundwater. The positive role of groundwater-recharge dam is indicated by the decrease in groundwater salinity and the rise in groundwater levels in their locations. The amounts of water harvested by groundwater-recharge dams in UAE during the period 1983–2005 are presented in Fig. 6.20 and listed in Table 6.9. The least amount of water harvested by these dams reached 2.4 Mm3 during the 1999–2000 season, while the largest amount of water retained by these dams reached 20 Mm3 during the 1994–1995 season. The low water harvest during the 2004 and 2005 seasons is related to the dry conditions prevailed during this period or incomplete data. The amount of water diverted by recharge dams to feed groundwater depends on rainfall, as listed in Table  6.9. Observation wells reflect the rise of groundwater levels in the water-well fields, which are usually drilled on the downstream side of these dams (Fig. 6.21). Figure 6.22 shows maximum, minimum and average annual discharge (Mm3) of the main drainage basins in northeastern UAE during the period 1992–2005. For example, Wadi Al Bih dam in Ras Al Khaimah Emirate has harvested a maximum water volume of 7.87 Mm3 during the season 1997–1998 of the period 1992–2005, Wadi Al Tawiyean dams, Wadi Zikt dam and Wadi Al Wurrayah dam harvested maximum water volumes of 6.63 (season 1994–1995), 6.10 (season 1994–1995)​​

6.8  Recharge Dams

Infiltration 55o 40’ Rate

219

55oof50’ Length Overland Flow

56o 00’

56o 10’

> 0.21

Very Low

14

0.21 - 0.25

Low Moderate

0.26 - 0.30

High

0.31 - 0.35

Very High

13

< 0.35

24o 30’

12 11 10 8

9

24o 20’

8 km

15 7 1

Jabal Hafit

Oman Mountains

6

Al Jaww Plain

2

5

24o 10’

4

3 3 4

5

2

1 24o 00’

55o 40’

55o 50’

56o 00’

Fig. 6.17  Ranking of the flash-flood hazard in various drainage basins of the eastern mountain ranges and Jabal Hafit, according to infiltration capacity. (After Rizk et al. 1998)

and 3.08 (season 2001–2002) Mm3, respectively, during the same period (Tables 6.10, 6.11, and 6.12). Fortunately, a significant part of this harvested water recharges groundwater. But, the storage capacity of dam reservoirs depends on many factors, such as the drainage area and height of the dam. The large drainage area enables a reservoir to harvest more water (Fig. 6.23). The records of flood water harvested by 22 dams during the period 2001–2005 show that Wadi Al Wurrayah in the Fujairah Emirate retained 3.0 Mm3 in 2002 and 3.5 Mm3 during the period 2001–2005 (Figs. 6.24 and 6.25).

220

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

A

B

C

Rb = 4

Rb = 2.25

C

Q/A

B A

Rb = 17

Time

Fig. 6.18  Theoretical surface runoff hydrographs, according to bifurcation ration (Rb). (Modified by Patton (1988) after Strahler (1964))

The total volume of water harvested by 22 dams during the period 2001–2005 in the Eastern and Central Regions of the UAE is depicted Fig. 6.26. The variation in the volumes of harvested water by various dams depends mainly on rainfall, with the volume of harvested water increasing with increasing rainfall.

6.8  Recharge Dams 55o 40’ Risk of Flash Food

221 55o 50’ Bifurcation Ratio

Very Low

56o 00’

56o 10’

> 4.5

Low

4.1 - 4.5

Moderate

3.6 - 4.0

High

3.1 - 3.5

Very High

14 13

< 3.1

24o 30’

12 11 10 8

9

24o 20’

8 km

15 7 1

Jabal Hafit

Oman Mountains

6

Al Jaww Plain

2

5

24o 10’

4

3 3 4

5

2

1 24o 00’

55o 40’

55o 50’

56o 00’

Fig. 6.19  Ranking of flash-flood hazard in various drainage basins of the eastern mountain ranges and Jabal Hafit, according to their bifurcation ratios (Rb). (After Rizk et al. 1998)

222

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Fig. 6.20  Volumes of runoff water (Mm3) retained by groundwater-recharge dams in the United Arab Emirates during the period 1983–2005

Table 6.9  Average runoff volume (Mm3), overland flow velocity and ranking, according to overland- flow velocity and flood hazard of selected drainage basins in Jabal Hafit area in the United Arab Emirates Wadi Name Al-Ain Tarabat Ain Al-Faydah Al-Ashkhar Milehah

Area (km2) 76.3 38.5 9.6

Predicted Runoff (Mm3) 0.67 0.34 0.08

Rank of Flash Flood Risk 2.0 5.0 4.0

Overland Flow Velocity 0.28 0.16 0.24

Rank of Overland Flow 2.0 3.0 5.0

48.6 54.3

0.43 0.48

3.0 1.0

0.26 0.31

1.0 4.0

6.8  Recharge Dams

223

Fig. 6.21  Fluctuations of groundwater levels, measured in observation wells behind main recharge dams in the United Arab Emirates, during the period 1992–2005

Fig. 6.22  Minimum, average and maximum annual runoff volumes in main drainage basins in northeastern UAE for the period 1992–2005

224

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Table 6.10  Volume of surface water (Mm3), retained behind groundwater recharge dams in northeastern UAE during the period 1992–2005 No. Season 1 91–92 2 92–93 3 93–94 4 94–95 5 95–96 6 96–97 7 97–98 8 98–99 9 99–00 10 00–01 11 01–02 12 02–03 13 03–04 14 04–05 Minimum Average Maximum

Name of basin and volume of retained water (Mm3/year) Bih Tawiyean Eden Hadf Zikt Wurrayah Baseerah 3.30 2.34 0.67 0.54 0.85 – – 2.00 1.40 – 0.70 0.28 – – – 1.15 0.51 0.25 2.00 – – 4.76 6.63 0.04 1.38 6.10 – – 2.35 2.65 2.06 2.68 3.50 – – 1.89 1.76 1.58 1.13 1.70 0.55 – 7.78 3.85 0.27 0.40 0.40 0.15 – 0.70 1.00 0.37 – – – – – 1.00 – 0.50 0.40 0.50 – 0.50 2.00 – – 0.50 0.25 – – 2.50 – – 1.60 3.08 – 3.40 2.00 – – 0.30 3.00 1.00 – – – – – 0.40 0.80 – – – – – 1.00 – 0.50 1.00 0.04 0.25 0.28 0.15 0.80 2.96 2.36 0.79 0.95 1.60 1.12 0.90 7.78 6.63 2.06 2.68 6.10 3.08 1.00

Gulfa 0.19 0.20 0.10 0.54 1.15 0.92 0.30 – – – – 0.30 – – 0.10 0.46 1.15

Total (Mm3) 7.89 4.58 4.01 19.44 14.39 9.53 13.15 2.07 2.40 3.25 7.18 10.00 1.20 1.00 1.00 7.15 19.44

Table 6.11 Fluctuation of groundwater levels (m), in observation wells at locations of groundwater-recharge dams in northeastern UAE during the period 1992–2005 No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Average

Year 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Basin and groundwater level in meters Bih Ham Eden Gulfa 5.85 5.65 27.61 28.53 3.27 3.42 20.89 41.33 0.00 3.40 5.90 49.82 4.72 29.28 16.66 44.97 4.40 21.16 8.41 0.00 3.50 12.09 1.52 35.77 7.51 0.00 – 27.63 5.08 50.87 1.98 23.71 2.31 6.17 2.74 0.00 1.00 9.06 1.90 0.00 0.63 5.52 3.23 0.00 3.74 0.00 1.69 0.00 2.97 37.87 0.00 0.00 1.48 30.09 0.00 0.00 3.39 22.46 4.77 33.02

Hadf 28.53 9.78 0.81 41.80 0.50 2.82 1.50 2.30 0.66 2.30 1.90 1.40 1.24 1.95 5.31

Zikt 18.52 2.97 9.53 23.04 1.88 2.94 0.33 8.47 5.12 14.92 0.88 17.60 0.00 16.06 9.12

Tawiyean 0.42 15.12 3.13 27.48 22.68 12.40 28.62 1.81 0.15 2.40 0.39 0.15 0.45 31.40 11.63

No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Physiographic Factor Catchment area (km2) Average width (km) Average length (km) Basin length along main stream (km) Perimeter (km) Perimeter of equivalent circle (km) Shape index Form factor Rotundity factor Compactness coefficient Elevation at the dam site (mamsl) Maximum elevation (m amsl) Average elevation (mamsl) Maximum relief (m) Average slope Time of concentration (min) Number of streams Stream density Length of main stream (km) Total length of stream (km) Drainage density Runoff coefficient (%)

Hadf 37.5 4.0 7.0 9.0 26.5 18.2 2.2 0.5 1.2 1.5 400 1311 855 911 7.9 80 62 1.7 11.5 80 2.1 12.0

Shawkah 54 5.1 12 13 34 26 3.1 0.3 2.5 1.3 270 912 591 642 3.9 120 108 2.0 17 120 2.2 10

Ham 90.0 5.0 12.5 15.0 41.0 29.7 2.5 0.4 2.0 1.2 50 1109 580 1059 5.3 124 131 1.5 20.0 149 1.7 8.0

Bih 475 19.3 41.0 43.0 118 77.2 3.9 0.3 3.1 1.5 65 2087 1046 2022 4.4 256 245 0.5 46.5 528 1.1 2.0

Shimal 120 6.3 20.6 21.5 66.5 38.9 3.9 0.3 3.0 1.7 110 1128 619 1018 4.6 141 287 2.4 22.0 237 2.0 14.0

Rumth 30.5 3.5 10.0 10.2 27.5 19.6 3.4 0.3 2.7 1.4 140 1013 577 873 8.3 63 35 1.2 10.5 45 1.5 19.0

Safad 26 4.5 7.0 8.0 22 18 2.5 0.4 1.9 1.2 55 846 451 791 7.5 66 31 1.2 11 39 1.5 19

Farfar 68 7.9 6.0 14 43 29 2.9 0.3 2.3 1.5 126 840 483 714 4.0 123 78 1.2 18 114 1.7 15

Gulfa 6.6 2.5 4.5 5.7 14 26 3.3 0.3 2.6 1.3 450 700 575 250 3.8 30 16 2.4 6.5 22 3.3 15

Shi 17 2.8 5.5 7.0 18 15 2.9 0.4 2.3 1.2 30 807 419 777 10 44 35 2.1 7.5 33 1.9 15

Ghail 6.0 1.6 3.7 5.9 14 8.8 5.8 0.2 4.6 1.6 3.0 700 509 382 6.3 46 26 4.3 6.0 43 7.2 13

Idhn 61 8.5 6.0 12 40 28 2.6 0.4 2.0 1.4 2.0 837 529 617 5.0 86 87 1.4 13 110 1.8 10

Masfut 76.0 7.2 10.0 18.0 43.0 30.0 1.4 0.4 1.0 1.4 340 1311 826 971 5.4 113 109 1.4 18.0 175 2.3 10.0 (continued)

Madha 94.0 8.8 10.0 11.5 37.0 34.4 1.4 0.7 1.1 1.1 65 1124 595 1059 5.3 124 111 1.2 20.0 141 1.5 12.0

Table 6.12  Flood volumes of the main wadis in the northern and eastern parts of the United Arab Emirates, in Mm3 during the period 2001–2005

6.8  Recharge Dams 225

14

13

12

11

7 8 9 10

5 6

No. 1 2 3 4

Physiographic Factor Catchment area (km2) Average width (km) Average length (km) Basin length along main stream (km) Perimeter (km) Perimeter of equivalent circle (km) Shape index Form factor Rotundity factor Compactness coefficient Elevation at the dam site (mamsl) Maximum elevation (m amsl) Average elevation (mamsl) Maximum relief (m)

Table 6.12 (continued)

50

1.4 0.7 1.1 1.1

33.3 29.7

Ghalilah 70 7.0 7.3 10.0

992

1459 1884

760

1489 1934

30

1.8 0.5 1.5 1.1

23.0 20.0

Sham 35 5.0 5.4 8.0

1416

792

1500

84

2.0 0.5 1.6 1.3

44.5 33.1

Naqab 90 7.0 12.3 13.5

1392

831

1527

135

4.0 0.2 3.2 1.7

85.0 50.0

Tawiyean 198 7.2 20.0 28.5

447

379

602

155

2.1 0.5 1.6 1.2

31 27

Mutarid 58 5.6 9.6 11

607

597

897

290

2.0 0.5 1.6 1.3

39 30

Mawrid 71 7.0 8.0 12

80

4.1 0.2 3.2 1.4

68.0 48.0

Wahala 185 6.3 25.5 27.5

894

677

967

564

1124 1047

230

1.8 0.6 1.4 1.1

37.5 28.4

Siji 88 6.2 11.6 12.6

359

404

583

225

3.8 0.3 3.0 1.5

37 24

Ashwani 46 3.9 13 13

850

625

1050

200

2.9 0.3 2.3 1.3

47.0 36.5

Sifuni 104 9.0 13.5 17.5

850

625

1050

200

1.9 0.5 1.5 1.2

64.0 52.1

Ashwani 216 9.6 10.5 20.0

691

474

819

182

2.7 0.4 2.1 1.5

92 92

Guor 303 15 16 29

98

1.7 0.6 1.4 1.3

52 40

Wurrayah 129 11 11 15

527 1063 858

597

1128 956

65

1.7 0.6 1.3 1.1

34.0 30.2

Zikt 73 7.8 8.7 11.0

226 6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

21 22

20

17 18 19

15 16

Average slope Time of concentration (min) Number of streams Stream density Length of main stream (km) Total length of stream (km) Drainage density Runoff coefficient (%)

1.0 18.0

35

30 0.9 8.0

18.0 38

1.1 16.0

79

40 0.6 12.0

16.0 55

1.3 18.0

120

91 1.1 16.0

8.9 86

1.7 15.0

339

222 1.1 33.0

4.2 199

2.9 12

169

57 1.0 16

2.9 129

2.1 12

150

132 1.9 17

3.6 127

1.6 15.0

138

150 1.7 15.0

6.0 95

1.7 10.0

320

219 1.2 34.5

2.8 241

1.9 13

85

70 1.5 16

2.2 145

2.5 14.0

260

175 1.7 18.5

4.5 123

1.7 14.5

366

270 1.3 26.0

3.3 184

1.9 15

579

380 1.3 32

2.2 251

6.0 15.0

434

295 4.7 21.0

5.0 131

2.3 12

301

371 2.9 28

3.1 194

6.8  Recharge Dams 227

228

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

Fig. 6.23  The areas (km2) and annual runoff volumes (Mm3) in main drainage basins in the UAE, during the period 1981–2005

Fig. 6.24  Volumes of runoff water (Mm3), stored behind main dams in Eastern and Central Regions of the United Arab Emirates during the period 2001–2005

6.8  Recharge Dams

229

Fig. 6.25  Ranking of runoff volumes (Mm3), stored by 21 dams in the Eastern and Central Regions of the United Arab Emirates During the period 2001–2005

Fig. 6.26  Total volumes of runoff water stored by 22 major dams in the Eastern and Central Regions of the United Arab Emirates during the period 2001–2005

230

6  Seasonal Floods: Harvesting and Contribution to Aquifers’ Recharge

References Al Shamesi MH (1993) Drainage basins and flash flood hazards in Al Ain area, United Arab Emirates. M.Sc. Thesis, Faculty of Science, UAE University, p 151 Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region. The Arabian Gulf and adjoining areas. Elsevier Publishing Company, Dordrecht, p 331 Garamoon HK (1996) Hydrogeological and geomorphological studies on the Abu Dhabi - Al Ain – Dubai rectangle, United Arab Emirates. Ph.D.  Thesis, Ain Shams University, Cairo, Egypt, p 277 Horton RE (1945) Erosional developments of streams and their drainage basins— hydrophysical approach to quantitative morphology. Geol Soc Am Bull 56:275–370 Hydroconsult (1978) Reconnaissance report and development proposals. Eastern Region Water Resources. Government of Abu Dhabi, Ministry of Petroleum and Mineral Resources Rep, Abu Dhabi Linsley RK, Franzini JB, Freyberg DL, Tchobanoglous G (1992) Water-resources engineering, 4th edn. McGraw-Hill, New York, p 841 McCullagh P (1978) Modern concepts in geomorphology. Oxford University Press, Oxford, p 128 MOEW (Ministry of Environment and Water) (2015) State of environment report. Ministry of Environment and Water, Abu Dhab, p 36 Patton PC (1988) In: Baker VK, Kochel RC, Patton PC (eds) Drainage basin morphometry and flood—in flood geomorphology. Wiley Interscience Publication, New York, pp 51–64 Rizk ZS, Alsharhan AS (2003) Water resources in the United Arab Emirates. In: Alsharhan AS, Wood WW (eds) Water resources perspectives: evaluation, management and policy, Developments in water science, vol 50. Elsevier, Boston, pp 245–264 Rizk ZS, Alsharhan AS (2008) Water resources in the United Arab Emirates. Ithraa Publishing and Distribution, Amman, p 624. (in Arabic) Rizk ZS, Garamoon HK (2006) The influence of major lineaments on groundwater resources in the eastern region of the United Arab Emirates University of Sharjah. J Pure Appl Sci 3(3):83–111 Rizk ZS, Alsharhan AS, Shindo SS (1997) Evaluation of groundwater resources of United Arab Emirates. Proceedings of the 3rd Gulf Water Conference. Sultanate of Oman, Muscat, pp 95–122 Rizk ZS, Garamoon KF, El-Etr HA (1998) Morphometry, surface runoff and flood potential of major drainage basins of Al Ain area, United Arab Emirates. Egypt J Remote Sens Space Sci 1(1):391–412 Sherif MM, Mohamed MM, Shetty A, AL Mulla M (2011) Rainfall-runoff modeling of three Wadis in the northern area of UAE. J Hydrol Eng 16:10–20 Strahler A (1964) Quantitative geomorphology of drainage basins and channel networks. In: Chow V (ed) Handbook of applied hydrology. McGraw Hill, New York, pp 439–476 White ID, Mottershead DN, Harrison SJ (1992) Environmental systems—an introductory text, 2nd edn. Chapman and Hall, London/New York, p 616

Chapter 7

Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

Abstract  This chapter discusses the hydrogeology, hydrochemistry and the therapeutic value of permanent UAE springs, e.g., Khatt (Ras Al Khaimah), Maddab (Fujairah) and Bu Sukhanah (Abu Dhabi). The springs are controlled by geologic structures, discharge of various rock types and their location at particular elevations. Results of this study showed that the 1984–1991 spring discharge rates ranged from 0.06 million m3 (Mm3/year) (Maddab) to 2.50 Mm3/year (Bu Sukhanah), with little change during this period. Based discharge rates, the sequence of the UAE springs in descending order is: Bu Sukhanah (second; discharge 2.5 is m3/s), Khatt north and Khatt south (fourth; discharges are 0.51 and 0.69 m3/s, respectively) and Maddab (fifth; discharge is 0.31 m3/s). The rainfall–discharge correlation showed that the amount of flow of Khatt springs is directly proportional to rainfall intensity. In contrast, the discharge rates of the Maddab and Bu Sukhanah springs are not directly related to rainfall intensity. Heavy groundwater exploitation during the period 1984–1991 appears to be the main cause of the increasing salinity of springs water, however, the increase of the salinity of the Bu Sukhanah spring’s water, with almost a triple increase in its discharge during the period 1984–1991, needs further investigation. High spring-water temperatures (30 °C, Maddab; 39 °C, Khatt north; 39.5 °C, Bu Sukhanah; 41 °C, Khatt south) can be related to deep groundwater circulation or radioactive decay at depth, as in the case of Bu Sukhanah spring. Plotting the 1991 and 1994 chemical analyses on Piper’s diagram revealed that the springs’ water types are the chloride of sodium and bicarbonate of magnesium. The sulphate (SO42− = 561–1862 mg/L) water of Bu Sukhanah spring (SO42− = 561– 1862  mg/L) suggests older age than the bicarbonate (HCO3−  =  200–322  mg/L) water of Khatt springs. The calculated SAR of the water of the studied UAE permanent springs decreases from 15 in Bu Sukhanah to one at Maddab Spring, showing that springs’ water is generally unsuitable for irrigation of conventional crops. However, the water of all UAE springs has a therapeutic value because of their warm water and high sulphur content.

© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_7

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232

7  Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

7.1  Introduction A springs was defined by Meyboom (1966) as an “outcrop” of groundwater, and by Todd and Mays (2005) as a surface flow of concentrated discharge of groundwater reaching the ground surface. For this reason, springs represent groundwater discharge areas in dry regions, where the groundwater level intersects the ground surface. Springs are classified based on discharge, water temperature and controlling geologic structure. Having fairly constant or extremely variable discharge, springs can be permanent or ephemeral (Fetter 1988). Springs can also be classified as gravity (depression, contact and fracture), artesian (fault and sinkhole) or others (thermal, geyser and fumarole). The UAE permanent springs Khatt and Bu Sukhanah are karst springs. Spring water may contain dissolved minerals and gases, with temperatures close to the air temperatures or lower or higher, or even boiling. Permanent springs in UAE are all called “sulphur springs“and have been used for therapeutic purposes. In fact, Khatt and Bu Sukhanah springs have already been developed as recreational areas and touristic sites. The objectives of this study are to investigate the hydrogeologic conditions, hydrogeochemical characteristics and therapeutic value of the permanent UAE springs illustrated on Fig. 7.1. To achieve these objectives, records of rainfall, spring discharge and water chemistry of studied springs and nearby shallow groundwater were extracted from the climatology and hydrology year books issued by the Ministry of Agriculture and Fisheries (MAF 1993). During January–May period, 1994, field visits were made to these springs and water samples were collected for chemical analyses, which were conducted at the General Food Quality Control Laboratory of Al Ain Municipality, Al Ain, UAE.

7.2  Locations of Springs Inspection of topographic maps by Rizk and El-Etr (1997) indicated that: “the approximate elevations (in meters above sea level) of the UAE springs under study are: 50 m (Khatt north and Khatt south), 250 m (Bu Sukhanah) and 300 m (Maddab). The Khatt springs are located in northeastern UAE, south the outlet of Wadi Usylah and west of Wadi Al-Hayer. Khatt area lies about 13 km east of Dibba and 15 km south of Ras Al-Khaimah. Maddab area is located within the ophiolite rocks in the middle of Fujairah City. Bu Sukhanah spring is located in Al Ain area, close to the UAE- Oman borders (Fig. 7.1)”.

7.3  Geologic Setting

233

o 54° Major city54

55°

56°

Permanent spring Approximate international boundaries

N

25°

Ras Al Khaimah Diba

ARABIAN

GULF

MK 14

Umm Al Quwain

Khatt Springs

Ajman

20 km

Sharjah

Masafi

Al Dhaid

Dubai

GP 146

Siji Spring

Fujairah

GULF OF OMAN

o

AN

25 25°

OM

Water well

Maddab Spring SHF 15 24°

Al Ghomour Spring

Kalba

24°

UNITED ARAB E M I R AT E S OMAN Abu Dhabi

Al Ain

23°

Bu Sukhanah 54°

55°

Spring

GWR 7

23°

56°

Fig. 7.1  Locations of studied UAE and selected groundwater-observation wells

7.3  Geologic Setting The Khatt North and Khatt South  springs occur in hard, gray limestone rocks that belong to the Musandum Formation. A thrust fault, which is dissected by several northwest–southeast and east–west trending wadis (see Photo 7.1), runs across the area in a north–south direction. Al Ghomour spring discharges ophiolite rocks in the Kalba area of the Sharjah Emirate at the extreme south of the eastern coastal plain (Photo 7.2). After deposition of Tertiary rocks within the ophiolite basin, uplift and weathering of all rocks produced the clastic rocks that bound the eastern mountain ranges on both sides. Maddab spring is located within ophiolite outcrops in Fujairah City. The spring seems to mark the intersection of more than one fault line (Photo 7.3). In the Fujairah area, the Semail ophiolite sequence is overlain by Quaternary alluvial sediments, which consist of sand and gravel.

234

7  Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

Photo 7.1  Khatt spring in the Ras Al Khaimah Emirate, discharging karstic limestone of the Ru’us Al Jibal Mountains, the northern UAE

The Bu Sukhanah spring lies west of Jabal Hafit, which is composed of an Upper Cretaceous-Miocene limestone-dolomite sequence composed of marl, clay and evaporites at its top (Photo 7.4).

7.4  Rainfall Spring discharge rates, especially seasonal and ephemeral ones, are directly related to rainfall. A spring discharge increases with increasing rainfall and decreases or even disappears in the absence of it. The rainfall over the UAE shows a pronounced variation in space and time, and so do the discharge of springs. Despite its limited area (10% of the total of the UAE), the eastern mountain ranges receive about 30% of the total annual rainfall, about 90% of which occurs during February and March (Alsharhan et al. 2001). The average annual rainfall in UAE (120 mm for the whole country and 160 mm for the eastern mountain ranges) shows a wide variation from 1  year to another. While the average annual rainfall of the season 1981–1982 was 282 mm, reaching 450 mm in some mountainous areas, the average annual rainfall of season 1984–1985 was 24 mm in Abu Dhabi (Fig. 4.13). This figure shows that the rainfall in the UAE

7.5  Springs’ Discharge

235

Photo 7.2  Al Ghomour spring in the Kalba area of the Sharjah Emirate, south Eastern Coastal area of the UAE

increases in the north and east (220  mm at Ras Al Khaimah and Masafi) and decreases in the south and west (40 mm at Liwa and Bu Hasa in Abu Dhabi).

7.5  Springs’ Discharge Spring discharge ranges from a barely perceptible seepage to more than 30  m3/s (Todd and Todd 1980). Most springs fluctuate in their discharge rates in response to variations in geologic settings and hydrogeologic conditions. To define the magnitude of springs, Menizer (1923) proposed a classification by discharge (Tables 7.1 and 7.2). The discharge of a spring depends on the aquifer properties and the recharge area. In coastal areas containing limestone or volcanic rock aquifers, large subsurface channels often discharge groundwater through openings to the sea. Such submarine springs were discovered along both eastern and western coasts of the UAE in 1979

236

7  Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

Photo 7.3  Maddab spring in the Fujairah Emirate, Eastern Coastal area of the UAE

Photo 7.4  Bu Sukhanah spring in the Al Ain area of the Abu Dhabi Emirate

7.5  Springs’ Discharge

237

Table 7.1  1984–2004 records of the average annual rainfall (mm) at Khatt, Fujairah, Maddab and Bu Sukhanah meteorological stations (data obtained from the Ministry of Climate Change and Environment)

Year 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Meteorological station Khatt Fujairah Mean annual rainfall in millimeters 22.4 28.7 35.0 12.4 42.4 65.4 109.0 193.6 215.0 290.4 66.4 77.2 123.8 141.8 90.2 56.6 116.2 126.2 235.4 134.2 29.6 179.0 118.4 172.6 446.6 531.2 212.8 204.4 321.6 168.2 76.2 40.4 20.6 2.8 52.0 58.8 26.6 56.6 58.6 36.0 33.6 7.6

Maddab

Bu Sukhanah

73.6 34.4 80.8 180.8 222.4 55.6 222.4 41.2 125.2 102.6 27.2 105.0 266.8 198.4 230.6 56.2 15.2 55.2 46.0 47.8 4.8

1.0 21.6 40.2 57.2 113.7 91.2 140.6 44.2 106.6 136.2 8.2 96.6 214.2 171.4 91.8 29.0 8.0 4.4 31.1 0.6 7.3

Table 7.2  Meinzer’s (1923) classification of springs according to discharge Spring order First Second Third Fourth

Mean discharge (m3/s) > 10 1:10 0.1:1 0. 01:0.1

Spring order Fifth Sixth Seventh Eighth

Mean discharge (L/s) 1:10 0.1:1 0.01:0.1 0.001:0.01

Todd and Todd (1980)

during a survey conducted by the Ministry of Agriculture and Fisheries (Ghoneim 1991). These springs need further study. The recharge area of a spring may vary between less than 100 m2 to more than 13,000 km2 (Fetter 1988). Spring discharge increases with an increasing recharge area. However, large springs may discharge from a relatively small recharge area, depending on local hydrogeologic conditions. Records of spring discharge in the UAE were obtained from the Ministry of Agriculture and Fisheries (MAF 1993) for the period 1984–1991 (Table 7.3).

238

7  Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

Table 7.3  1984–1991 records of the annual discharge (Mm3) of the UAE permanent springs

Year 1984 1985 1986 1987 1988 1989 1990 1991 2000 2002 2004 2006

Springs Khatt north Khatt south Average annual discharge (Mm3) 0.54 1.04 0.44 0.60 0.23 0.13 0.22 0.30 0.67 0.76 0.35 0.35 0.51 0.63 0.51 0.69 0.54 0.55 0.38 0.40 0.13 0.15 0.29 0.30

Maddab

Bu Sukhanah

0.09 0.06 0.09 0.13 0.13 0.13 0.13 0.13 0.0 0.0 0.0 0.0

0.96 1.10 1.42 1.58 1.51 1.45 1.58 2.50 – – –

MAF (1993)

Between 1984 and 1991, the discharge of the UAE springs varied from 0.06 Mm3 in Maddab spring to 2.50 Mm3 in Bu Sukhanah spring, with a decrease in Khatt springs and an increase in Bu Sukhanah spring. The discharge of UAE springs and their classification according to Meinzer (1923) is illustrated in Table 7.4.

7.6  Rainfall-Discharge Relation The annual discharge rates of the springs under study were compared with the total annual rainfall at the nearest meteorological stations. This comparison indicates that the UAE springs are two types (Fig. 7.4); springs of discharge dependent on rainfall, such as Khatt and Maddab springs, and springs with discharge independent of rainfall, such as Bu Sukhanah. Correlation of rainfall records (Table 7.1) and spring discharge rates (Table 7.3) for the period 1984–1991 illustrate the direct correlation between the total annual rainfall recorded at Khatt meteorological station and the discharge of Khatt north and Khatt south springs. Khatt north spring recorded its highest discharge rate (0.67 Mm3/year) in 1988, which also has the highest total annual rainfall (215 mm). Similarly, Khatt south spring has recorded its highest discharge rate (0.76  Mm3/ year) in the same year (Fig. 7.2). Despite the wide variation in rainfall, Rizk and El-Etr (1997) noticed that: “the discharge of Maddab spring has remained constant at 0.13 Mm3/year. The discharge of Bu Sukhanah spring has increased from 1.58 Mm3/year in 1990 to 2.50 M m3/ year in 1991, whereas the total annual rainfall has dropped from 140.6 mm in 1990 to 44.2 mm in 1991”.

7.7  Groundwater Levels–Discharge Relation

239

Table 7.4  Classification of the UAE permanent springs, according their discharge and Minzer’s (1923) ordering Year 1984 – BS – KN, KS SJ

Spring Order 1 2 3 4

Discharge (m3/s) >10 1:10 0.1:1 0.01:0.1

5

0.001:0.01

6 7 8

0.0001:0.001 – 0.00001:0.0001 – 180 mg/L). The high total hardness of groundwater in the Wadi Al Bih aquifer is associated with high concentration of both Ca2+ and Mg2+, which are released from the dissolution of limestone and dolomite rocks forming the aquifer matrix (Al Asam et al. 2005).

294

9  Limestone Aquifers 60

3500

A

50

2500 Cl (mg/L)

K (mg/L)

40 30

ine

gl

20

r

ate

w ea

10 0

B

3000

xin mi

200

400

rm

1500

a

Se

1000

600

800

0

1103

0

500

Na (mg/L) 80

C

250

0

w

1000 Na (mg/L)

1500

2000

150

200

ter mixin

50

Sea wa

40 30 20 10

Se

0

aw

50

Mg (mg/L)

ne g li ixin rm ate

SO4 (mg/L)

60 200

100

e at

D

70

150

e

g line

300

lin

500

S 0

i

2000

g

n xi

500 1000 1500 2000 2500 3000 3500 Cl (mg/L)

0

0

50

100 Ca (mg/L)

Fig. 9.7  Presentation of selected ions (a) K versus Na, (b) Cl versus Na, (c) SO4 versus Cl, and (d) Mg versus Ca, proves the absence of a relationship between groundwater and seawater in the Wadi Al Bih limestone aquifer. (After Rizk et al. 2007)

Groundwater quality for irrigation purpose is generally expressed by the class of relative suitability, taking sodium content and electrical conductivity into consideration, since sodium may cause an increase in the salinity of the soil, as well as a reduction in its permeability (Todd 1980). According to the U.S.  Salinity Laboratory (1954), electrical conductivity and sodium adsorption ratio (SAR) should be considered in determining the suitability of water for irrigation use. The relationship between electrical conductivity (EC) and SAR is used for evaluation of the suitability of groundwater for irrigation, and its possible adverse effects on plant and soil (Table 9.5; Richards 1969). The SAR of the groundwater in the Wadi Al Bih basin ranges from 1.6 to 16. About 74% of collected groundwater samples from the study area can cause ­moderate harmful effects for plants, and 26% of groundwater samples are characterized by limited harmful effects to plants and soils.

9.1 Northern Limestone Aquifer

295 40

L

W

LM GM W

L

30

Y = 4.3x + 8.9 2

r = 0.93

Deuterium (‰ SMOW)

20 10 -10

-8

-6

-4

-2

0

Gulf Sea Water

0

2

Brine ?

4

6

8

10

-10 -20

Wadi Al Bih Groundwater

-30

Y = 2.8 x 0.29 r 2 = 0.62

GMWL D = 8

18

LMWL D = 4.3

O + 10 18

O + 8.9

-40

Oxygen - 18 (‰ SMOW)

Fig. 9.8  Relationship of stable isotopes of hydrogen (2H) and oxygen (18O) for the global rainwater line, local rainwater line and groundwater in the Wadi Al Bih limestone aquifer, Ras Al Khaimah Emirate. (After Rizk et al. 2007)

4.0

3.5

Tritium Content (TU)

3.0

2.5 2.0

1.5

1.0

0.5

0.0 0

200

400

600

800

1000

1200

1400

1600

1800

2000

Chloride Ion Concentration (mg/l)

Fig. 9.9  Plot of tritium (3H), in tritium units (TU), versus chloride-ion concentration (in mm/L) in the Wadi Al Bih limestone aquifer in 1996. (After Rizk et al. 2007)

296

9  Limestone Aquifers

Table 9.5  Classification of groundwater in Wadi Al Bih limestone aquifer, according to its suitability for irrigation EC-SAR class C3-S1 C4-S1 C4-S2

Al Bih well field 5-9-20-21-24-25-25X-29-30-31 3-7-14-15-16-19-22-23-26-2728-­32-33-34-35-36-37-38 1-2-4-6-10-11-12-13-18

Tawi Al Burayrat HD-SF RF

Al Burayrat well field 23-X2 2-15-26-X1X3 5-10-11-25X4-­X5

Suitability for Irrigation Suitable Suitable Unsuitable

9.1.6  Water Problems The results of chemical analysis show an increase in the average concentration of total dissolved solids (TDS) in the aquifer by 28%, during the summer due to groundwater pumping, lack of rain and the absence of groundwater recharge during this season. The iso-salinity contour map shows a steady increase in groundwater salinity towards the Arabian Gulf (Fig. 9.5), indicating that the groundwater recharge is limited to the eastern part of the limestone aquifer in the Wadi Al Bih basin. Sodium-ion concentration increases in the Al Burayrat well field, reinforcing the hypothesis of seawater intrusion into the aquifer (Fig.  9.5). This phenomenon is accelerated by the low groundwater level in the Al Burayrat water well field, which is five meters below mean sea level (Fig. 9.3). The average concentrations of lead (Pb) is 0.13  mg/L in Wadi Al Bih and 0.12 mg/L in Al Burayrat. The average level of selenium (Se) is 0.20 mg/L in in Wadi Al Bih and 0.44 mg/L in Al Burayrat, which are above the WHO (1984) and the GCC (GSO 2008) standards for drinking water (Table 9.6). The severity of the problem is that the water wells with high concentrations of lead are located in the eastern part of the aquifer, where groundwater is fresh and is used for drinking and domestic purposes. For this reason, it is recommended to repeat the chemical analysis of groundwater samples from that area to verify current measurements and communicate with FEWA, which owns the water-well field in the Wadi Al Bih basin, to take suitable measures in case high lead concentration is confirmed. Trace elements are very important water-quality indicators, and their presence at high concentration indicates water contamination. The trace elements; Fe, Li, Sr, Ba, B, Cr, Zn, Ni, Pb, Cu, Co, Cd, Mn, As and Se were analyzed in the collected samples during winter and summer. Concentrations of the elements, Cr, Co, Cd, As and Mn, in the analyzed water samples are below the detection limits. Apart from the ionic input from seawater intrusion and limited amount of recharge to the Wadi Al Bih limestone aquifer, dissolution of minerals in the ­geologic material through which the water flows contributes remarkably to the water chemistry. The enrichment of the Burayrat water, in heavy metal such as Zn and Ni relative to water of Al Bih well field, can be explained by the differences in dissolution rate of geologic materials in both areas.

9.1 Northern Limestone Aquifer

297

Table 9.6  Trace elements measured in water well fields in the Wadi Al Bih Basin versus the international (WHO 1984) and regional (GSO 2008) drinking-water standards Element F− Fe B Zn Ni Cu Li Sr Ba Pb Se

Wadi Al Bih Max. Min. 2.31 0.00 0.48 0.00 0.37 0.01 0.90 0.00 0.51 0.00 0.06 0.00 0.33 0.10 4.28 0.46 0.37 0.02 0.60 0.00 1.56 0.00

Mean 0.47 0.08 0.08 0.26 0.16 0.02 0.17 1.70 0.16 0.13 0.20

Al Burayrat Max. Min. 2.44 0.00 0.25 0.00 0.37 0.00 1.55 0.00 0.52 0.04 0.10 0.00 0.20 0.14 3.21 0.88 0.24 0.10 0.34 0.00 2.27 0.00

Mean 0.94 0.07 0.10 0.34 0.30 0.01 0.17 2.27 0.17 0.12 0.44

WHO Guideline 1.50 0.3–1.0 – 5.00 – 1.0–1.5 – – – 0.05 0.01

GCC Max. level 0.6–1.7 0.30 – 5.00 – 1.0 – – – 0.05 0.01

Chemical analyses are in mg/L.  Averages are calculated for the total number of samples. Not detected (ND) was replaced by zero

The alkaline nature of the studied water samples is directly responsible for the exceedingly low concentration of Fe, which seems to precipitate as hydroxide. The removal of iron from the groundwater leads to a remarkable decrease in water density. The precipitation of iron hydroxides may cause serious impoverishment in the content of some heavy metals (for example, V, As and Zn) in water, as a result of scavenging (Faure et al. 1995). During summer, the trace elements Zn, Ni and Fe increased, while B and F− remarkably decreased. In summer, Zn has increased by eleven times greater than the winter concentration, Ni doubled and Fe increased 1.4 times. The decrease in F− and B contents were eleven and four times, respectively. Strontium (Sr) is a seawater indicator element. According to Hem (1992), the seawater contents of Sr and Li are eight and 1.7 /L, respectively. The distribution of these elements proceeds toward the Gulf direction. The distribution patterns of lead (Pb) and selenium (Se) are opposite to those of strontium (Sr) and lithium (Li) because their contents are below the detection limits in the west, and their maximum values were measured in downstream side of the secondary dam, at the entrance of Wadi Qada’a. The Cl/(CO32− + HCO3−) ratio was used by Alsharhan et al. (2001) and Rizk et al. (2007) to study the possibility of salt-water intrusion in Wadi Al Bih limestone aquifer and stated: “If the ratio is less than one, there is no salt-water intrusion, but if the ratio is more than one, then the aquifer is suffering from salt-water intrusion. In the eastern part of Wadi Al Bih the values of Cl/(CO32− + HCO3−) ratio are less than one, while the ratio is more than one in the west, especially towards the end of the summer, which increases the possibility of salt-water intrusion during this period. It is possible to summarize the factors affecting groundwater quality in Wadi Al Bih limestone aquifer in weathering of the limestone rocks forming the aquifer and salt-water water intrusion from a deep saline source in the eastern part of the

298

9  Limestone Aquifers

Table 9.7  The use of hydrochemical parameters for identification of the processes affecting water quality in Wadi Al Bih limestone aquifer Ratio Na/(Na + Cl) Mg/(Mg + Ca) Cl−/sum anions HCO3−/sum anions

Suggested value < 0.5TDS > 500 < 0.5 > 0.8 and TDS > 500 < 0.8 < 0.8

Study area 0.25–0.40 0.40–0.49 0.62–0.86 0.05–0.25

Conclusion Seawater Limestone-dolomite weathering Seawater, evaporites Rock weathering Seawater

aquifer. Table  9.7 shows the use hydrochemical coefficients for identification of groundwater pollution sources. The intensive groundwater exploitation from Wadi Al Bih limestone aquifer during the period 1980–1994 has led to degradation of groundwater quality; the problem still existing in the present (Fig. 9.6)”. Some calcium and carbonate ions are added to groundwater through weathering of limestone rocks forming the aquifer during water movement. But, the majority of other ions are added to the aquifer through upwelling of brine water from deep horizons in the aquifer into fresh groundwater in the upper part. This brine contains less sulphate, chloride and potassium ions than seawater (Fig. 9.10). This conclusion is consistent with the results obtained through the use of geochemical models, which indicate that the origin of high salinity in the aquifer is not a result of mixing of rainwater feeding the aquifer and saline water from the Arabian Gulf. In fact, it is difficult for saline water from the Arabian Gulf to move 30 m above sea level to intrude into the groundwater of the main well fields near the Wadi Al Bih main dam. Results of stable isotopes study indicate that the groundwater in the Wadi Al Bih aquifer comes from rainwater recharging the aquifer at an elevation of 1000 m or higher, not seawater. It appears that the recharge area is the Ru’us Al Jibal mountain peaks surrounding the limestone aquifer in the Wadi Al Bih basin. It also seems that excessive aquifer exploitation has led to upwelling of brine from the aquifer’s deep layers (Al Asam et al. 2005). The aquifer’s water comes from rain, and its salts come from the aquifer depths (Fig. 9.11). The study of isotopes and carbonate chemistry indicate that the main portion groundwater produced by the FEWA well field comes from the Wadi Al Bih recharge dam (Fig. 9.9). Murad et  al. (2014) studied the impact of climate change on groundwater resources in Wadi Al Bih basin in the Emirate of Ras Al Khaimah. Groundwater in the basin was sampled in 2005, 2011 and 2014 and the total dissolved solids (TDS in mg/L), electrical conductivity (EC) in microsiemens per centimeters (μS/cm) and temperature in degrees Celsius (°C) and pH were measured directly in the field during sampling. Records of temperature and rainfall during the period 1997–2014 show a general increase in mean groundwater temperature with decreasing rainfall, indicating that the study area is expected to have less rainfall as temperature continues to rise in the future.

9.2 Jabal Hafit Limestone Aquifer

I +C

80

80 60

CO

60

+H 3

40

CO

40

20

80 60

40

Mg

3

4

40

SO

20

20

20

20

40

20

Ca

20

SO 4

80

40

40

60

60

60

+K

60

SO4 80

HDW

40

Na

80

20

RK 6

20

80

Ca

Mg

40 Sea Water

Rain

Mg

+ Ca

60

60

80

80

299

SO4 + HCO3 % mg/l

Na + K

CATIONS

80

60

40

20

CI + HCO3

Cl ANIONS

Fig. 9.10  Presentation of the results of chemical analyses of water from the Wadi Al Bih limestone aquifer in 1996, on Piper’s diagram. (After Rizk et al. 2007)

Results show that the mean average temperature during the last 17 years of the period 1976–2014 has increased 1.02 °C compared to the first 20 years. During the same period, a drastic drop in the average rainfall from 151.3  mm to 81.3  mm, meaning that the average rainfall decreased around 46% during the last 17-year period compared to the first 20 years.

9.2  Jabal Hafit Limestone Aquifer The Mubazzarah well field is located in a valley at the northern end of Jabal Hafit, south of Al Ain City in the Eastern Region of the Abu Dhabi Emirate. Fifteen wells, 90 to 200 m deep, were drilled, producing a combined 21,000 m3/day of thermal, brackish water with temperatures of 36 to 52 °C, TDS concentrations of about 3900 to 6900 mg/L and high concentrations of radium-226 and radon-222 gases.

300

9  Limestone Aquifers

Carbonate Rocks Evaporite-rich Layers Shale Precipitation

Al Burayrat

Wadi Al Bih

Faults and Fractures

Arabian Gulf

water

Table

Sea Level r

ate hW

s

Fre Seawater-Groundwater Interface

n atio

liltr

Inf

r

ate hW

kis

Bra

ne

Bri

Fig. 9.11  Schematic cross section illustrating the hydrogeologic conditions of the Wadi Al Bih limestone aquifer. (After Rizk et al. 2007)

This water is now used for recreational and therapeutic purposes and, to a limited extent, in landscaping. The following discussion is an attempt to identify the source(s) of this water, its chemical characteristics and therapeutic value.

9.2.1  Hydrogeology of the Dammam Aquifer in Jabal Hafit The hydrogeologic setting of the Dammam aquifer is the Jabal Hafit area and was studied by Khalifa (1997): “Jabal Hafit anticline consists of 1500 m thick limestone and marl with interbeds of gypsum, evaporite and dolomite formations of Lower Eocene to Miocene (Hamdan and Bahr 1992). The Middle Eocene Dammam limestone Formation constitutes the main aquifer in Jabal Hafit (Photo 9.1). Whittle and Alsharhan (1994) indicated that, except for infrequent, unfilled fractures, vugs and heterogeneous secondary porosity, the porosity of the Dammam limestone is virtually nil. The aquifer is affected by numerous faults and fractures and is characterized by extensive dolomitization, which enhances development of secondary porosity (Yehia and Nasr 1992). The normal geothermal gradient indicates that the depth of the hydrological cycle varies between 1500 and 2100 m (Khalifa 1997). The high yield of water wells, which amounts 4600 m3/day, is related to the high

9.2 Jabal Hafit Limestone Aquifer

301

Photo 9.1  Water wells of the Mubazzarah well field, discharging warm, saline groundwater from the Al Dammam aquifer in northern Jabal Hafit, south of the Al Ain Region of the Abu Dhabi Emirate (Rizk and Alsharhan 2008)

hydraulic conductivity associated with fractures and karst features resulting from chemical weathering of limestone and dolomite forming the aquifer”. According to Terratest (1975), Jabal Hafit limestone rocks contain black organic deposits along joints and bedding plains. These black deposits have 21 parts per million (ppm) of uranium. Upon decomposition, radium-226 and radon-222 gases escape into the air once the groundwater pumped from the aquifer reaches the atmosphere. Well logging, which includes well diameter, temperature and water hydraulic conductivity, indicates the possible presence of a confined-flow carbonate system, based on the model prepared by Stringfield and Le Grand (1966). Logs were described by Khalifa (1997) as: “A colour television inspection of water wells, tapping the Middle Eocene aquifer in Jabal Hafit, revealed that most of the rocks-­ forming the aquifer consist of massive limestone and marl, of low porosity and permeability, as well as very little prospect of producing water. The exception to this is the rock section at depth between 101 and 112 m, which is composed of karstic and intensively fractured carbonate. Karanjac (1997) reported that the widths of fracture in this rock section are as great as 9 cm, indicating that this interval could produce most of the water yielded by the well. He also pointed out that a flowmeter survey for the same well revealed that high-temperature water was flowing into the well from limestone fractures in the interval from 93 to 102 m”.

302

9  Limestone Aquifers

9.2.2  Hydrogeochemistry The hydrochemical characters of the aquifer were summarized by Rizk et al. (2007) in the following: “The maximum permissible limit of radium-226 (Ra226) in drinking water is 5 picocuries per liter (US Environmental Protection Agency 1991). Ra226 has no maximum permissible limit in drinking water. The groundwater s­ alinity in the Mubazzarah well field exceeds the maximum permissible limit for drinking water (TDS > 1500 mg/L) and is not suitable for drinking or domestic uses. But, no risk is associated with using this water as a recreational spa, irrigation of salt-­ tolerant crops and landscaping (Polytechna 1996). Table  9.8 shows that the temperatures in thermal wells range from 36.5 to 51.4 °C. The water is generally slightly alkaline (pH 7–8), rich in sodium chloride and its total dissolved solids (TDS) level ranges from 3900 to 6900  mg/L.  The results of chemical analyses in Table  9.8 pointed to the presence of two geochemically different types of water in Jabal Hafit. The first type of water is relatively low in temperature and TDS, while the second type of water is relatively high in temperature and TDS. Sodium is the dominant Table 9.8 Major (A), minor and trace (B), chemical constituents (mg/L) in groundwater of Mubazzarah water field, Jabal Hafit, in the Al Ain area, the eastern UAE A. Major Ions TDSb Ca Mg Na K No. ECa JH.1 7150 4800 375 135 1100 35 JH.2 8260 5500 575 150 1325 50 JH.4 9240 6200 575 145 1325 50 JH.5 5860 3900 325 140 975 33 JH.7 6330 4200 325 150 1075 35 JH.8 7150 4800 425 145 1200 40 JH.9 10,250 6900 600 200 1450 60 JH.10 9550 6400 550 175 1400 55 a EC Electrical conductivity in μS/cm; b TDS Total dissolved solids in mg/L; and Concentrations of cations and anions are in mg/L B. Minor and trace chemical constituents No. T pH B Ba Zn Cl/Br JH.1 37.1 7.24 13.50 117 235 253 JH.2 49.3 7.14 1100 171 28 122 JH.4 51.4 7.17 1100 174 375 184 JH.5 36.7 7.14 1200 142 165 241 JH.7 37.2 7.34 1650 134 500 392 JH.8 37.9 7.06 1150 115 235 214 JH.9 47.0 7.03 1250 184 32 186 JH.10 36.5 7.08 1500 154 28 101

TC 78.71 100.54 100.1 71.55 76.94 86.85 111.71 104.76

HCO3 226 123 107 182 198 151 122 154

SO4 775 450 500 500 625 550 600 750

Cl 2000 3000 2950 1900 2000 2500 2300 2900

NO3 0.81 0.48 0.14 1.10 2.50 0.25 0.39 0.54

TA 76.38 96.32 95.71 67.20 72.88 84.72 107.9 100.3

Sr 5 24 23 23 30 20 29 25

F 0.07 2.27 2.27 1.79 1.79 2.27 2.41 2.14

Si 11 14 15 10 10 12 14 12

Br 7.9 14 16 7.9 5.1 12 18 14

Mn 0.039 0.053 0.060 0.039 0.039 0.046 0.067 0.062

Fe 0.68 0.92 0.99 0.75 0.87 0.78 1.06 0.94

T Temperature in °C; Concentrations of Sr, Fe, Mn, Si, Br, Mn and Fe are in mg/L; and Concentrations of B, Ba and Zn are in μg/L

9.2 Jabal Hafit Limestone Aquifer

303

cation and chloride is the dominant anion. The high chloride concentration in the Dammam limestone aquifer in Jabal Hafit indicates upwelling salt water from a deep source. In this regard, Maddy (1993) pointed out upconing of saline groundwater (> 15,000 mg/L) under Al Ain city due to excessive pumping groundwater for different purposes. The pumping rate is ten times the natural recharge through rainfall. The source of high magnesium and sulphate ions in the aquifer is related to dissolution of thin layers of dolomite, gypsum and evaporites in the rocks-forming the aquifer in Jabal Hafit area”.

9.2.3  Isotope Hydrology The natural isotopes deuterium (2H), tritium (3H) and oxygen-18 (18O) in the hot groundwater of Jabal Hafit indicate that part of the water comes from a recent source of recharge. The depletion of18O and2H, compared to their standard values, indicates that the aquifer recharge occurs at high elevation, possibly Jabal Hafit itself (Alsharhan et al. 2001). In a projection of White’s (1977) simulation model on Jabal Hafit, there are three water-bearing zones: an upper fresh water zone replenished by local rain, a middle brackish-water zone where saline water mixes with freshwater and a lower saline-­ water zone (Fig.  9.12). The model assumed mixing of water from two sources, including recharge water originating from rainfall on the Jabal itself, and high-­ salinity water moving upward under temperature or gas drive from about 2000-m

Precipitation Jabal Hafit Infiltration

Mubazzarah Well Field Vadose Zone

Fresh Water Clays Brackish Water Saline Water

Fig. 9.12  Cross section in Jabal Hafit, south of Al Ain City, illustrating a hypothetical model for recharge and discharge of the Dammam limestone aquifer. (Modified after Khalifa 1997)

304

9  Limestone Aquifers

deep (Hutchinson 1996). The brackish water forms as a result of mixing of the two water types, which leads to lower temperature and TDS in the aquifer. Concentrations of stable isotopes of hydrogen (2H) and oxygen (18O) in the aquifer’s groundwater support this model. Concentrations of the two isotopes in the Jabal Hafit limestone aquifer is lower than their concentration in groundwater of the surrounding area supporting the hypothesis of local recharge at high elevation (Table 9.9).

9.2.4  Geothermal Energy of Groundwater The source of groundwater temperature is the Earth’s heat flow from inside towards the surface and the normal geothermal gradient of 3 °C for each 100 m of depth. Khalifa (1997) used the silica concentration in groundwater of the Mubazzarah well field for calculation of ground temperatures in Jabal Hafit area and the depth from which hot water originates. He concluded that temperature varies between 67 and 83  °C and that the depth from which hot water originate varies between 1500 and 2100 m.

9.2.5  Groundwater Uses The Dammam limestone aquifer at Jabal Hafit area has high salinity and temperature. The water in this area is now used for recreation, tourism and irrigation. However, Polytechna (1996) believes that the groundwater in this area has curative and therapeutic and values. The water in this aquifer system is unfit for drinking or domestic purposes but could be used for irrigation of salt-tolerant plants. The well Table 9.9  Concentration of radioactive elements and stable isotopes of oxygen (18O) and hydrogen (2H) in groundwater of the Mubazzarah water field in Jabal Hafit of the Al Ain Region of the Abu Dhabi Emirate

Well Number JH-1 JH-2 JH-4 JH-5 JH-7 JH-8 JH-9 JH-10

Radium 226 (226Ra pCil/L) 3.2 457 428 1.3 0.9 7.2 349 81

Radon - 222 (222Ra pCi/L) 489 2836 1743 1698 2064 1557 2399 6063

Uranium 238 (238U μg/L) 3 – 0.5 2.1 – – 1.0 –

Tritium (3H TU) 0.89 0.3 0.55 1.39 0.45 0.85 0.20 0.78

Deuterium

Oxygen 18

(‰2H) −8.57 −10.1 −10.7 −8.13 −8.34 −9.86 −10.99 −11.64

(‰18O) −8.57 −10.1 −10.7 −8.13 −8.34 −9.86 −10.99 −11.64

9.3 Limestone Aquifers in the Western Region

305

field in the Mubazzarah area in the northern part of Jabal Hafit was developed into a recreational area.

9.3  Limestone Aquifers in the Western Region Table 9.10 shows the main aquifers in the western UAE (NDC-USGS 1996). The limestone aquifers in the area are highly saline and include the Simsima, Umm Ar Radhuma and Dammam formations. Water from these aquifers is injected into oil reservoirs to maintain pressure. Figure 9.13 and Table 9.11 show the hydraulic properties of these aquifers.

9.3.1  Simsima Aquifer The carbonate sequence of the Simsima aquifer includes three units mainly composed of carbonate rocks. The Simsima aquifer reaches a maximum thickness of 366  m at the center of the Falaha syncline, from which the thickness decreases towards the north, west and southwest. The TDS, water uses and hydraulic properties in the Western Region of the UAE are listed in Tables 9.10 and 9.11.

Table 9.10  Main aquifers and uses of their water in the Bu Hasa oil field in the western UAE (compiled from NDC-USGS 1996) Hydrogeologic unit Liwa aquifer

Thickness (m) 135

Lower Fars confining unit

160

Miocene Clastics aquifer Dammam aquifer

Lithology and nature Eolian sand aquifer

Salinity (mg/L) 3000 5000

100

Evaporites and clastics confining unit. Sand aquifer

Importance and use Domestic supply, wash water and fire fighting Prevents vertical flow

100,000

Receives injected brines

265

Limestone aquifer

70,000

Rus confining unit

215

unknown

UER aquifer

415

Anhydrite and limestone confining unit. Limestone aquifer

Source of water for injection into reservoirs None

Simsima aquifer

270

Limestone aquifer

230,000

160,000

Source of water for injection into reservoirs Source of water for injection into reservoirs

306

9  Limestone Aquifers

Disposal System

Water Injection Facilities

Water Disposal Well

Water Supply Water Injection Well Well

Production Facilities Producer well Domestic Water Supply Aquifer (Liwa Aquifer) Fars Formation Waste-Water Disposal Aquifer (Miocene Clastics Aquifer) Dammam Brine Production Aquifers

Rus Umm Er Radhuma Simsima

Reservoir

Water Disposal

Water Injection

Fig. 9.13  Schematic cross section showing injection of saline groundwater in oil-producing layers, and disposal of wastewater in a clastic aquifer in the Western Region of the Abu Dhabi Emirate. (After Al Amari 1997)

Table 9.11  Porosity, permeability, transmissivity and storage coefficient of limestone aquifers in the western UAE. (After Hassan and Al Aidarous 1985)

Aquifer Dammam UERa Simsima

Porosity (%) 22–25 15–25 06–35

Intrinsic Permeability (k) Darcy cm/sec 0.02–0.04 1.7 × 10−5 – 3.4 × 10−5 0.01–0.05 8.5 × 10−6 – 4.3 × 10−6 0.0001–0.4 8.5 × 10−8 – 3.4 × 10−4

Transmissivity (T) (ft2/day) 30–60 40–150 15–220

Storage Coefficient (Sc) 6.8 × 10−4 9.0 × 10−4 4.0 × 10−4

UER = Um Ar Radhuma aquifer

a

9.3.2  Umm Er Radhuma Aquifer The Umm Er Radhuma Paleocene-Eocene aquifer was described by Alsharhan et al. (2001) and ESCWA (2005) as: “composed of four lithological units; the basal unit is represented by shales and marls, the third unit is composed of dolomitic mudstones and wackestones, the second unit consists of mudstones, packstones, grainstones and wackestones and the upper unit is composed of shaly lime mudstones, wackestones, and fine-grained packstones with dolomites. The aquifer’s total thickness varies between 305 and 610  m. The hydraulic properties of the aquifer are summarized in Table 9.11”.

References

307

9.3.3  Dammam Aquifer The Eocene Dammam aquifer was described by Alsharhan et al. (2001) as: “composed of dolomite with intercalations of shales and argillaceous limestone and anhydrite. The aquifer thickness ranges from 60 to 488 m, with a gradual increase in thickness from west to east. Despite the high average porosity of the core samples, the aquifer’s intrinsic permeability is low. Table 9.11 shows the porosity, permeability, transmissivity and storage coefficient of the Dammam aquifer in western UAE”.

References Abu Al Enien H (1996) Wadi Al Bih alluvial fan water resources: Al Kuwait University, Geography Department, Publ. No. 198, p 78 Akiti TT, Gonfiantini R, Mutawa A (1992) Aspects of isotope hydrology of the United Arab Emirates. Ministry of Electricity and Water internal report, p 50 Al Amari KA (1997) Assessment of environmental impact of re-injecting oil-field water in the Miocene clastic sediments on the shallow aquifer at Bu Hasa oil field, United Arab Emirates. Unpublished MSc thesis, UAE University, Al Ain, United Arab Emirates Al Asam MS (1998) Application of geophysical and geochemical techniques for assessment of groundwater recharge from Wadi Al Bih dams, Ras Al Khaimah, United Arab Emirates. Unpublished MSc thesis, UAE University, Al Ain, United Arab Emirates Al Asam MS, Al Matari A, Garamoon H, Suwaid N (2005) GIS-based Hydrogeological Studies for the Assessment of Groundwater Recharge from the Dam of Wadi Al Bih, UAE. In: Proceeding of the 7th Gulf water conference water in the GCC-towards an integrated management, WASTA, 19–23 November, State of Kuwait (1): 423–435 Al Wahedi AA (1997) Application of hydrogeochemistry and groundwater modeling techniques for water-resources management of Wadi Al Bih drainage basin, United Arab Emirates. Unpublished MSc thesis, UAE University, Al Ain, United Arab Emirates Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region: the Arabian Gulf and adjoining areas. Elsevier Publishing Company, Amsterdam, p 331 Bouwer H (1978) Groundwater hydrology, vol 480. McGraw-Hills, New York Electrowatt (1981) Wadi Bih dam and groundwater recharge facilities: Ministry of Agriculture and Fisheries, UAE, p 67 Erikson E (1983) Stable isotopes and tritium in precipitation: Guidebook on nuclear techniques in hydrology. Technical report series no. 91, IAEA, pp 19–33 ESCWA (2005) Development of frameworks to implement national strategies of integrated water resources management in the ESCWA countries: United Nations, New York, p 94 (in Arabic) Faure G, Hagen EH, Johnson KS, Strobel ML, Whiting KS (1995) Geological exploration of East Antarctica: Iron, manganese and titanium in the heavy minerals fraction of till in the Transantarctic Mountains. In: Elliot DH, Blaisdell GL (eds) Contribution to antarctic research IV. Antarctic research series, vol 67. American Geophysical Union, Washington, DC, pp 19–31 Glennie KW, Boeuf MGA, Hugh Clark MW, Moody-Stuart WFH, Piller WFH, Reinhardt PM (1974) Geology of the Oman mountains, parts I, II, III. Verh Kon Nederlands Geol Mijn Gen Trans Geol Survey 31:423 Gonfiantini R (1992) Investigation of ground water resources of the United Arab Emirates by using isotope techniques: IAEA report (UAE/8/92), Vienna, Austria, p 34

308

9  Limestone Aquifers

GSO (GCC Standardization Organization) (2008) Bottled Drinking water, GSO5/FDS/1025/2008, 22 p Hamdan AA, Bahr SA (1992) Lithostratigraphy of the Paleocene succession of northern Jabal Hafit, Al Ain, UAE. MERC Ain Shams Univ Earth Sci Ser 6:201–224 Hassan AA, Al-Aidarous A (1985) Regional aquifer geology  – onshore Abu Dhabi. Geology Department, ADCO project report 1584–50, Abu Fhabi, U. A. E., p 28 Hem JD (1959) Study and interpretation of chemical characteristics of natural water. U.S. Geological Survey water supply paper no. 1473, p 363 Hem JD (1992) Study and interpretation of chemical characteristics of natural water, U.  S. Geological Survey water supply paper no. 2254, 3rd edn, p 263 Hudson RGS (1960) The Permian and Triassic of the Oman Peninsula Arabia. Geol Mag XCVII(4):299–308 Hudson RGS, Chatton M (1959) The Musandam limestone (Jurassic to Lower Cretaceous) of Oman, Arabia. Museum National D’histoire Naturelle, Paris, vol VII, pp 69–91 Hunting (1979a) Geological map of the United Arab Emirates. Ministry of Petroleum and Mineral Resources, Abu Dhabi Hunting (1979b) Report on a mineral survey of the U.  A. E. 1977–1979, vol 1. Ministry of Petroleum and Mineral Resources, Abu Dhabi, pp 1–34 Hutchinson C (1996) Groundwater resources of Abu Dhabi Emirate: US Geological survey administrative report, p 136 Karanjac MA (1997) Hydrogeology of the geothermal fractured-rock well field at Jabal Hafit, Abu Dhabi Emirate. In: Proceeding of the third Gulf water conference—towards efficient utilization of water resources in in the Gulf, Muscat, Sultanate Oman, pp 125–140 Khalifa MA (1997) Hydrogeology of the geothermal fractured-rock well field at Jabal Hafit, Abu Dhabi Emirate. In: Proceedings of the third Gulf water conference, Muscat, Sultanate of Oman, pp 125–140 Langenegger O (1990) Groundwater quality in rural areas of western Africa. UNDP-Project INT/81/026, p10 Maddy DV, Editor (1993) Ground-water resources of Al-Ain area, Abu Dhabi Emirate, U.S. Geological survey administrative report 93–001, p 332 Murad A, Hussein S, Arman H (2014) Possible impact of climate change on water resources: a case study, Ras Al Khaimah (Wadi Al Bih), Northern United Arab Emirate. Recent advances in environment, ecosystems and development, pp 122–127 NDC-USGS (1996) Potential for contamination of the Liwa aquifer by disposal of brine in Bu Hasa and Asab fields, U.A.E.: Private consultant’s report for Abu Dhabi Company for Onshore Oil Operations (ADCO), p 73 Polytechna (1996) Evaluation of water springs analyses, Mubazzarah well field near Al-Ain, United Arab Emirates. Polytechna Ltd., Prague, p 12 Richards LA (1969) Diagnosis and improvement of saline and alkali soils. United States Salinity Laboratory Staff, Agriculture handbook no. 60, U.S. Government Printing Office, Washington, DC Rizk ZS (2015) Why Wadi Ab Bih limestone is the most sustainable aquifer in the United Arab Emirates? Int J Sustain Water Environ Syst 7(1):21–28 Rizk ZS, Alsharhan AS (2008) Water resources in the United Arab Emirates. Ithraa Publishing and Distribution, Amman, p 624. (in Arabic) Rizk ZS, Wood WW, Alsharhan AS (2007) Sources of dissolved solids and water in Wadi Al Bih aquifer, Northern United Arab Emirates. Hydrogeol J 15(7):1553–1563 Stringfield VT Le Grand HE (1966) Hydrology of limestone terrains in the coastal plain of the southeastern United States. Geol Surv Am Spec Paper 93:45 Terratest (1975) Abu Dhabi mineral survey – Stage II. Detailed investigation of promising areas, Final report. Phase II – Ain bu Sukhanah (unpublished report) Todd DK (1980) Groundwater hydrology, 2nd edn. Wiley, New York, p 535

References

309

U.S. Environmental Protection Agency (1991) Drinking water regulations and health advisories. U.S. Environmental Protection Agency Report, p 12 U.S.  Salinity Laboratory Staff (1954) Diagenesis and improvement of saline and alkali soils, Agricultural handbook no. 60. U.S. Department of Agricultural, Washington, DC, pp 60–160 Wagner W (1997) Renewable groundwater resources in dry areas of the ESCWA region – origin and isotopic characteristics: a regional training workshop on geochemical modeling methods for geochemistry evaluation and water pollution studies: UAE University, p 11 White WB (1977) Conceptual models for carbonate aquifers: revisited. In: Dilamarter RR, Csallany SC (eds) Hydrologic problems in karst regions. Western Kentucky University, Bowling Green, pp 176–187 Whittle GL, Alsharhan AS (1994) Dolomitization and chertification of the Early Eocene Rus Formation in Abu Dhabi, United Arab Emirates. Sediment Geol 92:272–285 WHO (World Health Organization) (1984) WHO guidelines for drinking water quality: volume 1, recommendations, Geneva, p 130 Yehia MA, Nasr A (1992) Use of Thematic Mapper Landsat Satellite Data for the study of the Geology and Geomorphology of Jabal Hafit, UAE. Earth Sci Ser 6:169–183 Yurtsever (1992) Preliminary evaluation of isotope results from reconnaissance samples collected in Kuwait. IAEA Technical Cooperation project, Isotope Hydrology of the Middle East, p 12 Yurtsever (1996) Isotope methods in water resources management and examples of applications in the Gulf region: Water Management Conference, Abu Dhabi

Chapter 10

Ophiolite Aquifer

Abstract  The Semail ophiolite rocks represent a low-productivity aquifer in the eastern and northeastern UAE.  But, it can function as a good aquifer where it is faulted, fractured and jointed. The aquifer’s average transmissivity and specific yield are 776 m2/d and 0.24, respectively. Despite the high transmissivity and storativity of the ophiolite fractured aquifer in the eastern UAE, the thickness, distribution and recharge mechanism for the aquifer are poorly defined. The groundwater quality in the aquifer is good because its matrix is hardly soluble in water. But, the salinity increases with increasing depth due to lower density of fractures, smaller size of cracks and slow groundwater-flow velocity. The three structural zones affecting the ophiolite aquifer are: the Wadi Ham line, Dibba zone and Hatta zone. The result of a Transient Electromagnetic (TDEM) survey revealed the presence of two aquifers separated by an aquiclude. The upper aquifer has a variable thickness, increasing from 60 m, at the foothills of the eastern mountain ranges, to 160 m in a northwest–southeast trending trough. The aquifer trough is composed of gravel of the Neogene age and has minor marl and sandstone intercalations. The aquifer’s maximum thickness is 200 m, decreasing to 70 m in the southwest. The middle aquiclude is composed of impermeable Paleogene shale, claystone, marl and dolomite, and attains 300 m north of Falaj Al Mualla, decreasing to 50 m southeast of Al Dhaid City. The lower aquifer is more productive along the Dibba zone and includes Aruma Group and Semail ophiolites of the Maastrichtian to Pre-Cretaceous ages. The influence of lineaments on groundwater chemistry is an indirect result of their control on groundwater-flow velocity and residence time. The salinity of groundwater in the ophiolite aquifer is generally low in the east and increases in the groundwater-flow directions towards the west, northwest and southwest. Lineaments affect the dominance of dissolved ions in groundwater, particularly magnesium (Mg2+) and bicarbonate (HCO3−) ions, which are the most dominant ions in the eastern part of the aquifer. The Dibba zone and Wadi Ham line have cold (32 °C) groundwater that is rich in Mg2+ and HCO3−.

© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_10

311

312

10  Ophiolite Aquifer

10.1  Introduction The studies of IWACO (1986) and JICA (1996) on the Eastern Region confirmed the presence of a good aquifer in the fractured ophiolites of the eastern mountain ranges of the UAE. The aquifer’s transmissivity is 776 m2/d, and its specific yield is 0.24. The study of Murad and Krishnamurthy (2004) added to our knowledge about the ophiolite aquifer and its recharge mechanism. The groundwater quality in the ophiolite aquifer is generally good because the rocks forming the aquifer are hardly soluble in water. It was noted that the salinity of groundwater in the ophiolite aquifer increases with increasing depth due to the lower density of fractures, smaller cracks size and slow groundwater-flow velocity (Ministry of Agriculture and Fisheries 1993; Rizk et al. 1997; Bakhit 1998). This chapter describes the use of lineation analysis to investigate the ophiolite aquifer in the Eastern Region of the country, and to define the effect of major lineaments on groundwater potentiality, hydraulic heads, hydrogeochemical characteristics and water quality. Recently, lineaments analyses were extended to explore the effect of linear structural trends on groundwater flow, recharge, storage and discharge (Magowe and Carr 1999). Lineaments analysis was applied to “Al Dhaid Super Basin“, named by Rizk and Garamoon (2006), which drains the fractured ophiolite aquifer in the Northern Oman Mountains (the eastern mountain ranges) in its eastern portion. The basin covers a large area including part of the mountains in the east and a large tract of the gravel plains in the middle and sand-dune fields and coastal area, overlooking the Arabian Gulf in the west (Figs. 10.1 and 10.2). Straight segments of the drainage network dissecting rock outcrops within the study area were traced from topographic maps scale 1:50,000 and 1:100,000. Linear elements were also traced from Landsat satellite images at scales 1:100,000 and 1:250,000. Groundwater levels were measured in observation wells of the Ministry of Climate Change and Environment and about 100 farm wells during the period 1996–1998. Records of water levels prior to 1996 were obtained from the MAF in Dubai (UAE National Atlas 1993). Water samples collected from private farm wells were analyzed for major ions in the Central Laboratories of the MAF.  The UAE National Atlas (1993) described three structural zones affecting the eastern mountain ranges in the UAE. These zones do not only affect groundwater resources but also control the distribution of urban centers, farms, water-well fields and sabkha deposits.

10.2  Geomorphologic and Geologic Features The salient geomorphic features in the Al Dhaid Super Basin include: the eastern mountain ranges, western gravel aquifer, sand dunes, sabkha deposits and drainage basins. The rock outcrops of the ophiolite aquifer represent a part of the eastern mountain ranges. A part of these mountains covers the eastern part of the Al Dhaid super basin (668 km2) and is characterized by a rough terrain and steep slopes, with elevations between 250 and 1500  m. The drainage network dissecting these mountains

313

10.2 Geomorphologic and Geologic Features

55o 50`

25o 25`

55o 55`

56o 00`

25o 25`

29

30

LEGEND

31

Observation wells used for water-level measurements

51 50

Private farm wells sampled for hydrogeochemical investigations

46

54

53

47 45

56

55

36

44

GP -01 (Nasim)

43

37

76

57

41

58

77

33

71

70

4 25o 15`

39

72

Al Dhaid

69

GP-17

66

38

ARABIAN GULF

OMAN

10 km

74

75

56o 00`

26o 00`

To Masafi

GP -16 (East Dhaid)

25o 45`

98

96

95

UNITED ARAB EMIRATES

25o 15`

97

GP-14

Northern Agricultural Region

25o 30`

(Siji)

94 93

67

(Borair)

73

GP -15 (South Dhaid)

68

26

2

40

Road

25o 20`

28

34

42

Falaj Al Mualla

Al Dhaid City

35

1 92

3

79

84 90

81

61

23 20

22 17

23

O M A N

82 55o 45`

89

62

GP -07 (Meleiha)

7

59

30oN

I

R

A

N

A

60

25o 05`

R

18

24o 45`

56o 15`

30oN

6

A

25o 05`

Al Dhaid Super Basin

25o 00`

Al Madam Plain

86

83

63 24

25o 10`

87

64

78

GP -06 (Hamdah)

25o 15`

8

5 62

25o 10`

OMAN

Al Dhaid Area

91

GULF OF OMAN

49 25o 20`

GP -03 (Manama)

Northern Oman Mountains

41

B I A N

GP -11 (Sahlguf)

GU

BAHRAIN

LF

QATAR

Dubai

GU

LF

Abu Dhabi

16 25o 00`

5 km

11 14 55o 50’

13 55o 55’

19 12

56o 00’

OF

OM

AN

UNITED ARAB EMIRATES

25o 00`

20oN

S A U D I A R A B I A 50oE

O M A N 20oN 60oE

Fig. 10.1  Location of the Al Dhaid Super Basin. (After Rizk and Garamoon 2006)

exhibits a dendritic pattern where the lithology is uniform (Fig. 10.2), while trellis and rectangular patterns are dominant where faults and joints exist (Yehia and Nasr 1992). The geomorphology and geology of the Al Dhaid Super Basin were investigated by Rizk and Garamoon (2006), who indicated that: “Wadi channels are generally filled by unconsolidated Pleistocene sand and gravel, which are locally cemented forming conglomerate. Vast areas are covered by flood-plain deposits, mixed with recent loose gravel and sand, overlie these sediments. The continuous down cutting formed many stepped river terraces, and deep grooves along wadi channels at piedmont plains of the mountain ranges”. The western part of the Al Dhaid Super Basin (867 km2) is mainly covered by river terraces, alluvial fans and flood-plain deposits, representing an extensive plain constituting the western gravel aquifer. The plain extends between the foothills of

314

10  Ophiolite Aquifer 55o 45`

26o 00`

56o 00`

56o 15`

A R A B I A N G U L F

26o 00`

O M A N

Ras Al Khaimah 25o 45`

Umm Al Quwain

Ru’us Al Jibal

25o 30`

G U L F

Wadi Lamhah

Diba

OF OMAN

25o 45`

25o 30`

Khor Fakkan

Al Dhaid Plain

Masafi

OM

Al Dhaid 25o 15`

AN

UNITED ARAB EMIRATES

25o 15`

Northern

Fujairah Oman

Mountains Kalba

Al Madam Plain

25o 00`

25o 00`

LEGEND Mountains Gravel plains

Masfut

Sand dunes Inland sabkhas 24o 45`

0

10

20

30 km

O M A N

Coastal sabkhas 55o

56o 00`

56o 15`

24o 45`

Fig. 10.2  Geomorphologic map of the eastern UAE, where the ophiolite aquifer constitutes almost one half of the rock outcrops. (After Rizk and Garamoon 2006)

10.3 Morphometry

315

the mountain ranges in the east to the sand-dune fields in the west and includes the most fertile and agriculturally productive area in the country. The continuity of the alluvial plain is interrupted by the anticlinal ridges of Jibal Al Fayah in the west. The channels of several wadis originate in the eastern mountain ranges, cross the alluvial plain and merge together into Wadi Lamhah, which is a single wadi channel moving from south to north and reaching the Arabian Gulf north of Umm Al Quwain.

10.3  Morphometry The methodology of morphometric investigation of the Al Dhaid Super Basin was summarized by Rizk and Garamoon (2006) as follows: “The watershed area of each sub-basin was outlined, traced and measured with a planimeter. Then, the drainage lineation map of the Al Dhaid Super Basin was prepared from topographic sheets of different scales (Fig. 10.3). The stream numbers in each order were counted and recorded in Table 10.1, for calculation of the bifurcation ratio (Rb), drainage density (Dd) and stream frequency (Fs)”. The stream orders in each sub-basin were also plotted versus stream numbers on a semi-logarithmic scale. The plots of the five sub-basins constituting the Al Dhaid Super Basin are all linear, with correlation coefficients of 0.98–0.99 (Fig. 10.4). The azimuth frequency diagram for the mountains area, based on drainage lineation data, shows the three main lineaments (Fig. 10.5a), but the azimuth diagram for the gravel plain reflected the Wadi Ham line and Hatta zone trend and concealed the Dibba zone lineament (Fig. 10.5b). The azimuth diagram based on satellite images for the eastern mountain ranges within the study area shows the dominance of the lineaments of Dibba and Wadi Ham over the Hatta zone lineament (Fig. 10.6a). The drainage lineation map shows that 763 linear segments were traced within the Al Dhaid super basin, 216 lines (28%) affecting the gravel plain and 547 lines (72%) dissecting the eastern mountain ranges within the study area (Table 10.2). Results of the presentation of the azimuth angle versus the percentage of linear segments in each azimuth class revealed the dominance of three trends, identified Rizk and Garamoon (2006) as: “The N20°E, N70°E and N30°W, which represent the Dibba zone (NE-SW), Hatta zone (ENE-WSW) and Wadi Ham (NW-SE) lineaments, respectively (Fig. 10.6b). Table 10.3 shows the calculated values of basin area (A), bifurcation ratio (Rb), stream frequency (Fs) and drainage density (Dd) of each of the sub-basins in the Al Dhaid Super Basin. The total area (A) of the Al Dhaid Super Basin is 1525 km2 and the total number of stream segments is 1285”. According to Rizk and Garamoon (2006): “Bifurcation ratio (Rb) is the ratio of the number of streams of an order to the number of streams in the next higher order (Leopold et  al. 1964). The catchment areas of Al Dhaid Super Basin sub-basins were traced from topographic sheets and satellite images, and the areas of these sub-­ basins were measured by a planimeter. The average Rb of several basins in the United States is 3.5, while it ranges between 2.0 and 5.0 in Egypt (Leopold et al. 1964). The small Rb values mean fast

316

10  Ophiolite Aquifer 55o 45`

56o 00`

56o 15`

ARABIAN GULF 0

10

20

26o 00`

OMAN

Ras Al Khaimah

30 km

GULF OF OMAN

26o 00`

25o 45`

Umm Al Quwain

UNITED ARAB EMIRATES Wa

25o 30`

di

Northern Agricultural Region

La

m

ha

h

Northern Oman Mountains

Dibba

25o 45`

25o 30`

Khor Fakkan

Wadi Al Dhaid Masafi

Al Dhaid Wadi Kadrah

25o 15`

OMAN

25o 15`

Wadi Shawkah

Fujairah

Wadi Hamdah

Wadi Meleiha 25o 00`

Al Madam Plain

Al Dhaid Super Basin

Kalba

LEGEND

25o 00`

Main city Main road Main water divide

Masfut

Secondary water divide Drainage line Approximate international boundaries 24o 45`

55o 45`

56o 00`

OMAN 56o 15`

24o 45`

Fig. 10.3  Al Dhaid Super Basin and its five sub-basins, as drawn with the use of topographic maps of different scales. (After Rizk and Garamoon 2006)

10.4 Geologic Setting

317

Table 10.1  Number of stream channels in each stream order in the five sub-basins constituting the Al Dhaid Super Basin Stream order 1 2 3 4 5 6 7

Al Dhaid Super Basin 951 234 70.0 19.0 8.00 3.00 1.00

Sub-basin name Wadi Al Wadi Dhaid Kadrah 155 160 37 44.0 11 11.0 2.0 2.00 1.0 1.00 – – – –

Wadi Shawkah 236 63.0 15.0 5.00 2.00 1.00 –

Wadi Hamdah 165 35.0 15.0 5.00 2.00 1.00 –

Wadi Meleiha 235 55.0 18.0 5.00 2.00 1.00 –

floods and large values suggesting reduced floods (Leopold et al. 1964). The average (Rb) of the Al Dhaid sub-basins is 3.3, indicating a moderate flood potential. Stream frequency (Fs) is the total number of streams divided by the total area of the basin (Al Shamesi 1993). The average stream frequency (Fs) for the Al Dhaid sub-basins is 0.93. Based on stream frequency, a maximum probable flood will occur in Wadi Kadrah, whereas the least possible flood may occur in Wadi Hamdah. Drainage density (Dd) is the total length of all streams in a basin divided by its total area. It reflects the basin’s potential of runoff and infiltration. The average drainage density (Dd) of the Al Dhaid sub-basins is 1.16. In high-density basins the length of overland flow decreases and runoff velocity increases, while in low-density basins, both the length of overland flow and infiltration increase (Rizk et al. 1998)”. The drainage density (Dd) of sub-basins within the study area indicates that both runoff and infiltration capacity are equally important. The density of lineament intersections within the study area is represented on Fig. 10.7. The lineament-­intersections density is calculated by dividing the number of intersection by an arbitrary area (16 km2). The calculated values range from 0.06 to 0.49, and the areas of maximum density (3–7 intersections) show a clear match with the major lineaments (Figs. 10.5, 10.6, and 10.7).

10.4  Geologic Setting Vita Finzi (1973) subdivided the eastern mountains in the UAE into: “The eastern mountain ranges in the south, Dibba zone in the middle and Ru’us Al Jibal massif in the north. The Ru’us Al Jibal massif consists predominantly of a carbonate sedimentary sequence ranges in age from the Triassic to Lower Cretaceous. In general, broad folding, block faulting and complex local thrusting characterize the area (Hunting Geology and Geophysics Ltd. 1979). The Ophiolite complex is divided from top to base into sheeted-dyke complex and extrusive lava, fine-grained gabbros, coarse-grained gabbros, layered peridotite and an ultramafic mantle sequence (Glennie et al. 1974). The Dibba zone is an elongated northeast-southwest trending topographic depression, separating the Ru’us Al Jibal Musandum shelf in the northwest from the Semail Ophiolite sequence in the southeast. The eastern mountain

318

10  Ophiolite Aquifer 56° 00'

Ras Al Khaimah 26° 45'

1000

1

10 1 0 1 2 3 4 5 6 7

R2 = 0.984

Stream Order

100

Wadi Kadrah

1000 R2Dibba = 0.988

100 10

Stream Order Khor Fakkan

1

25° 15'

Wadi Hamdah 1000

Fujairah

R2 = 0.986

100

5 Wadi Meleiha

10 1 0 1 2 3 4 5 6 7

Stream Order

Al Madam Plain

LEGEND Main city Basin boundary Main water divide

20 30 km 55° 45'

Kalba 25° 00'

10 1

0 1 2 3 4 5 6 7

O M A N

Approximate international boundaries 10

R2 = 0.987

100

Masfut

Drainage line

0

1000

Stream Order

Secondary water divide

24° 45'

OM

Masafi

Al Dhaid

AN

0 1 2 3 4 5 6 7

Stream Number

Stream Number 25° 00'

25° 30'

0 1 2 3 4 5 6 7

Stream Order

25° 3 15'

26° 45'

1

Al Dhaid Super Basin Drainage Pattern

10

G U L F

R2 = 0.988

100

Stream Number

Stream Number

Wadi Shawkah

25° 1000 30'

Stream Number

O M A N

2 Wadi Al Dhaid

Umm Al Quwain 3

26° 00'

OF OMAN

A R A B I A N G U L F

56° 15'

UNI T EMI ED AR R A T AB ES

55° 45'

26° 00'

56° 00'

56° 15'

24° 45'

Fig. 10.4  Dominant drainage patterns in the Al Dhaid Super Basin and the relationship between stream numbers and stream order in its five sub-basins. (After Rizk and Garamoon 2006)

10.4 Geologic Setting

319

55o 45`

26o 00`

56o 00`

56o 15`

26o 00`

A R A B I A N G U L F

O M A N

Ras Al Khaimah 25o 45`

OF OMAN

25o 45`

A

Umm Al Quwain

25o 30`

G U L F

Dibba

UNITED ARAB EMIRATES

25o 30`

Masafi

Al Dhaid 25o 15`

OM

B

AN

Khor Fakkan

25o 15`

Fujairah

Kalba

Al Madam Plain

25o 00`

25o 00`

LEGEND

Main water divide Secondary water divide Drainage lines Lineament trend Masfut

Approximate international boundaries

O M A N

City 24o 45`

0

10

20

30 km 55o 45`

56o 00`

56o 15`

24o 45`

Fig. 10.5  Analysis of linear features in the Al Dhaid Super Basin, based on the main drainage lines and major linear trends in the Northern Oman Mountains (a), and the western gravel plain (b) (after Rizk and Garamoon 2006)

320

10  Ophiolite Aquifer 55° 45'

26° 00'

56° 00'

56° 15'

A R A B I A N G U L F

26° 00'

O M A N

26° 45'

Umm Al Quwain

UNITED ARAB EMIRATES

G U L F

Dibba

OF OMAN

Ras Al Khaimah

A 25° 30'

26° 45'

25° 30'

Masafi Al Dhaid

25° 15'

25° 00'

Lineaments (%)

100%

OMAN

Khor Fakkan

25° 15'

Fujairah

B

80%

Mountains

60%

Kalba

40% 20%

25° 00'

Gravel Plains

0% 0

20

40

60

80

100

120

140

160

Azimuth

Hatta Zone

LEGEND Fracture

Masfut

Fold

O M A N

Fault 24° 45'

0

10

20

30 km 55° 45'

56° 00'

56° 15'

24° 45'

Fig. 10.6  Map showing the fractures, folds and faults affecting the ophiolite aquifer in the eastern UAE, based on lineaments analysis. (After Rizk and Garamoon 2006)

10.4 Geologic Setting

321

Table 10.2  Drainage lines analysis of the Al Dhaid Super Basin, using topographic maps, scales 1:50,000 and 1:100,000 Azimuth Angle 0.00 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100 110 120 130 140 150 160 170 Total Percent (%)

Number of lines in gravel plains 13 2.0 5.0 8.0 8.0 11 9.0 8.0 4.0 26 15 8.0 26 25 24 17 4.0 3.0 216 28

Number of lines in mountains 80 7.0 4.0 32 21 79 41 14 17 53 29 8.0 16 39 57 29 7.0 14 547 72

Total number of lines 93 9.0 9.0 40 29 90 50 22 21 79 44 16 42 64 81 46 11 17 763 100

Table 10.3  Morphometric parameters of the Al Dhaid Super Basin, based on linear analysis of natural drainage lines Sub-basin Name Wadi Meleiha Wadi Hamdah Wadi Shawkah Wadi Kadrah Wadi Al Dhaid Average Total Periphery

Area (km2) 351 188

Bifurcation ratio (Rb) 3.09 2.91

Stream frequency (Fs) 0.9 1.19

Drainage density (Dd) 1.14 1.31

Number of streams 316 223

342

3.09

0.94

1.16

322

274 230

3.78 3.76

0.8 0.9

1.07 1.14

218 206

1525

3.33 0.93 The Al Dhaid super basin

1.16 1285 235 km

ranges comprise the northern part of the Semail Ophiolite nappe that is composed of a repeated Ophiolite sequence caused by internal low-angle thrust faults. The ophiolite rocks in the Eastern Region is a low productivity aquifer (Photos 10.1 and 10.2), except in the areas of intersections of main structural trends, including: NE-SW Dibba zone, NW-SE Wadi Ham line and ENE-WSW Hatta zone”.

322

10  Ophiolite Aquifer 55° 45'

56° 15'

56° 00'

A R A B I A N G U L F 0

10

20

30 km

26° 00'

O M A N

Ras Al Khaimah

OF OMAN

26° 00'

26° 45'

Umm Al Quwain

UNITED ARAB EMIRATES

G U L F

Diba

e

25° 30'

a

bb

Di

n Zo

26° 45'

25° 30'

Khor Fakkan

Al Dhaid

OMAN

25° 15'

25° 15'

Fujairah

W ad

iH

am

Li

ne Kalba

25° 00'

Hatta Zone

Intersections

>7 6-7 5-6 4-5 3-4 –510,000 Cl− Na+ NaCl  Ca2+ > Mg2+ > K+ in the west, Na+ > Mg2+ > Ca2+ > K+ in the center and Mg2+ > Na+ > Ca2+ > K+ in the east. The anion in water of the western gravel aquifer at Al Ain area has the order: Cl− > SO42+ > HCO3− > CO32− in the west, SO42+ > Cl− > HCO3− > CO32− in the center and HCO3− > Cl− > SO42+ > CO32− in the east (Fig. 11.34)”. The calculated, hypothetical water-dissolved salts in the western gravel aquifer in the Al Ain area are: Mg(HCO3)2, Ca(HCO3)2, Na(HCO3) and Ca(CO3) in the eastern part, Mg(SO4), Ca(SO4) and Na2(SO4) in the middle part, and Ca(Cl)2 and NaCl in the western part. Presentation of the chemical analysis of water in the western gravel aquifer on Piper’s diagram (Figs. 11.35 and 11.36), shows that the dominant water types are Mg(HCO3)2 in the eastern part, Ca(SO4) in the middle part and (NaCl) in the western part (Fig. 11.37). 11.2.2.4  Hydrochemical Profiles To study the influence of hydrogeologic conditions on the distribution of major ions and dissolved salts in the western gravel aquifer, three hydrogeochemical profiles were prepared (Fig.11.30). The first hydrochemical profile is oriented northeast– southwest and extends for 25 km (Fig. 11.38). As would be expected, the total concentration of all ions increased from east to west. The second profile is oriented north–south and extends for 28 km (Fig. 11.39). Across the profile against wells 11 and 18 (Fig. 11.30), two areas with noticeable low TDS reflect the presence of two buried alluvial channels running perpendicular to the profile direction, i.e. from east to west. These two channels carry relatively lower salinity groundwater than that in the surrounding area. The third hydrochemical profile runs east–west and extends for 25 km, reflecting the increase of groundwater salinity in the same direction, which is also the direction of groundwater flow. The TDS concentration at the western side of the profile is 10 times the TDS level at eastern side (Fig. 11.40). The profile shows the presence

376

11  Gravel Aquifers

Suweyhan

50

150 30'

24o

Suweyhan

30'

Aloha Al Ain AL Khaznah

300

50 0 10

Ca 2+

0 15

0 25

UNITED ARAB EMIRATES

24o

24o

00'

00'

OMAN

250

00'

30'

AL Hayer

Aloha Aloha Al Ain Al Ain

0 50 20 10 AL 10 Khaznah

24 2 o

24o

AL Wagan

50 100 150 0 20 UNITED ARAB EMIRATES

Mg2+

20 km

55o 30'

0 10

00'

20 km

AL Wagan

55o 30'

55o 30'

55o 30'

AL Hayer

AL Hayer 24o

Suweyhan

0 300

AL Khaznah

0 200

24o

24o

30'

30'

24o

Suweyhan

30'

00 Aloha 10

15

30'

24o

OMAN

30'

24o

10 0

24o

55o 30'

AL Hayer

50

100

55o 30'

Aloha Al Ain

Al Ain AL Khaznah

30 24o

24o

24o

00'

00'

00'

Na +

OMAN AL Wagan

55o 30'

24o 00'

60

20 km

K+

OMAN

UNITED ARAB EMIRATES

45

UNITED ARAB EMIRATES AL Wagan

20 km

55o 30'

Fig. 11.33  Contour maps showing the distribution of cations contour lines of the western gravel aquifer in Al Ain area. (After Garamoon 1996; Rizk et al. 1998)

of an inferred southwest–trending alluvial channel across Al Ain City. This channel was previously identified in the iso-concentration maps of major ions. 11.2.2.5  Minor Ions The minor constituents measured in western gravel aquifer in the Al Ain area include ammonia (NH3), nitrates (NO3−) and phosphates (PO32−). There is a high correlation between the distribution of high levels of ammonia (NH3) and agricultural activities in the Al Ain area (Fig. 11.41).

11.2  The Western Gravel Aquifer

377 55o 30'

50 30'

30'

24o

0

Suweyhan

Aloha Al Ain AL Khaznah

25

0

15

Aloha Al Ain

24o

00'

00'

55o 30'

24o 00'

OMAN

UNITED ARAB EMIRATES

HCO 3-

20 km

AL Wagan

0

15

50

24o

OMAN

20

15

CO 32-

25

UNITED ARAB EMIRATES

20 km

AL Wagan

55o 30'

55o 30'

55o 30'

AL Hayer Suweyhan

50

SO 4

2-

0 75

50 12

AL Wagan

55o 30'

30'

Aloha Al Ain

AL Khaznah

1000

UNITED ARAB EMIRATES

24o

Suweyhan

500

0

00'

30'

Aloha Al Ain

125

5000

AL Khaznah

24o

24o

30'

0 25 0

0

75

24o

24o

24o

00'

00'

1000 000 2 0 300

24o 00'

4000

OMAN

30'

AL Hayer

OMAN

24o

30'

AL 0 Khaznah 15

24o 00'

AL Hayer

0 25 0

24o

20

Suweyhan

24o

100

30'

10 1 2 5 0

24o

25 2 0 15

AL Hayer

1 20 5 0 0

55o 30'

5000 20 km

Cl

-

UNITED ARAB EMIRATES

3000 AL Wagan

20 km

55o 30'

Fig. 11.34  Contour maps showing the distribution of anion-contour lines of the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)

Freeze and Cherry (1979) confirmed that dissolved nitrogen in form of nitrates (NO3−) is the most common contaminant identified in groundwater and that nitrate moves with groundwater with no transformation and little or no retardation. NO3−-N is a health hazard in drinking water at levels in excess of 10 mg/L as NO3−-N, or 45 mg/L as NO3−. In the gastrointestinal tract, NO3− is reduced NO2−. The NO2− enters the blood, reacting with hemoglobin and preventing the blood from transporting oxygen. The intensive application of nitrogen fertilizers on farmlands is the main source of nitrate in groundwater of the UAE. The irrigation drainage water carries more the nitrogen that is more than plants can absorb, downwards to the groundwater causing

11  Gravel Aquifers

20

20

40

40

60

60

80

80

378

Ca CATIONS

20

40

40 60

20

60 40

60

20

80

Na+K HCO3 20 % mg/l

20

20

80

40

40

80

60

60

60

60

40

80

80

40

20

80

20

Ca

SO4

80

Mg

40

60

80

CI+HCO 3

Cl ANIONS

Fig. 11.35  Presentation of the chemical analysis of water in the western gravel aquifer in the Al Ain area, on a Piper’s diagram, performed in May 1994. (After Garamoon 1996; Rizk et al. 1998)

its contamination. Nitrate ion (NO3−) remains stable in groundwater as long as the flow path is oxygenated. This is the case with the western gravel aquifer, which is unconfined and has high concentration of dissolved oxygen, compounding the problem of groundwater pollution by nitrate. The natural distribution of phosphate ion in groundwater is very limited, despite the equal use of phosphate and nitrogen fertilizers. The concentration of phosphate in groundwater is much lower than the concentration of nitrate because phosphate adsorption in soil prevents its access to groundwater (Fig. 11.42). 11.2.2.6  Trace Constituents The iron (Fe) concentration in the western gravel aquifer in the Al Ain area varied between 0.05 mg/L east Al Ain and 15.8 mg/L northeast Zakher. Iron concentrations exceed the WHO (1971) drinking-water standard for iron in Al Wagan, Suweyhan, west Jabal Hafit and in the central part of Al-Ain city (Fig. 11.43).

11.2  The Western Gravel Aquifer

20

20

40

40

60

60

80

80

379

Mg 80 20

60 40

40 60

20 80

60 40 20

Ca CATIONS

20

Na+K HCO3 % mg/l

20

80

40

40

80

60

60

60

60

40

80

80

40

20

80

20

Ca

SO4

20

40

60

80 CI+HCO 3

Cl ANIONS

Fig. 11.36  Presentation of the chemical analysis of water in the western gravel aquifer in the Al Ain area, on a Piper’s diagram, performed in February 1995. (After Garamoon 1996; Rizk et al. 1998)

Because of the similarity of iron and manganese (Mn), manganese is almost absent in the eastern part of Al Ain and reaches its highest concentration northeast of Zakher. Groundwater on both sides of Jabal Hafit has a high concentration of strontium (Sr) due to the dissolution of celestite in these areas (Hunting Geology and Geophysics Ltd. 1979). Figure 11.44 shows contour maps of the distribution of copper (Cu), lead (Pb), zinc (Zn) and chromium (Cr) in the western gravel aquifer in the Al Ain area, Eastern Region of the Abu Dhabi Emirate. 11.2.2.7  Hydrochemical Coefficients The hydrochemical coefficient Na/Cl is less than unity (0.85) in seawater, but the coefficient is more than 1.0  in groundwater (Hounslow 1995). Therefore, these coefficients are used for determining aquifers suffering from saltwater intrusion. The possible sources of increasing salinity in the western gravel aquifer in the Al Ain area include brine water moving upward from aquifer depth or the movement

380

11  Gravel Aquifers

55o 30'

AL-AIN REGION

AL Hayer

O3 (HC

)2

Mg

24o 30'

Suweyhan

24o

O 4)

30'

S Ca(

Aloha Al Ain AL Khaznah SW 24o

l

NaC

00'

OMAN

00'

24o

UNITED ARAB EMIRATES

20 km

AL Wagan 55o

30'

Wells Road

Fig. 11.37  Classification of groundwater in the western gravel aquifer in the Al Ain area, based on its contents of hypothetical water-dissolved salts and results of presentation of chemical analysis of groundwater on a Piper’s diagram. (After Garamoon 1996; Rizk et al. 1998)

of brine water from a sabkha dominated area in the west and southwest towards the east, against the general direction of groundwater flow. The ratio Cl/(CO3 + HCO3) is also used for identification of saltwater intrusion into fresh aquifers. The Cl− is the most dominant in saline water, but usually has a low level in groundwater, while HCO3− is the most common in groundwater and has a low concentration in saline water. The results indicate that that the western gravel aquifer is suffering from saltwater intrusion in the western Al Ain area. The presence of MgCl2 and NaCl water-­ dissolved salts supports this hypothesis.

11.2  The Western Gravel Aquifer

381

K+ and Na+

CI-

Mg2+

SO42+

Ca2+

CO32- and HCO32 km

Vertical Scale

20 epm

Concentration (epm)

Horizontal Scale

54

SW

52

51

18

Water Wells

11

NE

Fig. 11.38  Northeast–southwest hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)

11.2.3  Isotope Hydrology The former UAE Ministry of Electricity and Water (MEW), in cooperation with the International Atomic Energy Agency (IAEA), has collected a large number of water- surface and groundwater samples for the eastern and northern UAE during the period 1984–1990 to investigate the isotope hydrology of the UAE. Deuterium (2H) and oxygen-18 (18O), tritium (3H) and carbon-14 (14C) were collected by the UAE MEW and measured by the IAEA, while the chemical analysis of the water was conducted by the MEW laboratories. Between 1993 and 1996, the authors collected 150 groundwater samples of rainwater, floods, springs and aflaj, in addition to groundwater samples from the Wadi Al Bih limestone aquifer, Jabal Hafit limestone aquifer, eastern gravel aquifer, western gravel aquifer and the Liwa Quaternary sand aquifer at the Liwa crescent and Bu Hasa oil field (Fig. 11.45). Samples were analyzed for2H,18O and3H in the IAEA central laboratories in Vienna, and complete chemical analyses of the samples were carried out in the Central Laboratories of the UAE University, Al Ain. Rizk and Alsharhan (1999) stated: “The stable isotope in groundwater of the western gravel aquifer plot to the right of the global meteoric water line (GMWL), reflecting possible enrichment of isotopes before recharge. Runoff water usually

382

11  Gravel Aquifers

K+ and Na+

CI+

Mg2+

SO42+

Ca2+

CO32 - and HCO3Vertical Scale

2 km

20 epm

Concentration (epm)

Horizontal Scale

55

S

15

14

13

12

6

43

Water Wells

58

28

19

22

23

24

N

Fig. 11.39  North–south hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)

collets in surface depressions in which it experiences evaporative enrichment before percolating towards groundwater. The presence of clays in alluvial deposits reduces their infiltration capacity. The recharge of the western gravel aquifer is limited to the eastern front which is adjacent to the eastern mountain ranges (Fig. 11.46). Increasing concentrations of chloride and stable isotopes confirm dissolution of salts by groundwater. The western gravel aquifer may contain old water, which mixes with recharge water moving through the aquifer”. The groundwater salinity increases as it moves through the western gravel aquifer from the eastern mountain ranges towards the Arabian Gulf. The water-table elevations for the aquifer indicated that the eastern mountain ranges in the UAE are the recharge areas for both the eastern and western gravel aquifers in the country (Symond et al. 2005). The Gulf of Oman represents the discharge area for the eastern gravel aquifer, and the Arabian Gulf is the main discharge area for the western gravel aquifer (Fig. 11.18).

K+ and Na+

CI-

Mg2+

SO42+

Ca2+

CO32- and HCO32 km

Vertical Scale

20 epm

Concentration (epm)

Horizontal Scale

55

W

52

50

49

Water Wells

45

1

57

68

E

Fig. 11.40  East–west hydrogeochemical cross section of the western gravel aquifer in the Al Ain area. (After Garamoon 1996; Rizk et al. 1998)

Fig. 11.41  Coincidence of areas of intensive agricultural activities with areas of nitrate pollution in the United Arab Emirates. (After Rizk 2014)

384

11  Gravel Aquifers

55o 30'

55o 30'

Suweyhan

30'

24o 30'

Suweyhan

24o 30'

0.8

10

1.0

30'

AL Hayer 24o

0.9

24o

0.8

10 50

AL Hayer

AL Oha

AL Oha 10

Al Ain 50

Al Ain

AL Khaznah 10

AL Khaznah

0.6

20

0. 6

8 0.

20 km

PO 42 -

AL Wagan

24o 00'

OMAN

24o 00'

UNITED ARAB EMIRATES

OMAN

40

50

24o 00'

afit

55o 30'

50

al H

AL Wagan

Jab

UNITED ARAB EMIRATES

afit

30

NO 3-

al H

Jab

10 20

24o 00'

20 km

55o 30'

Fig. 11.42  Contour maps showing iso-contour lines of nitrate and phosphate in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)

High-temperature groundwater centers, such as Khatt springs in Ras Al Khaimah, the water wells of Al Dhaid in Sharjah, Hatta area in Dubai, south of Wagan in eastern UAE, are located along north–south trending faults marking the western boundary of the eastern mountain ranges in the UAE (Fig. 3.10). These centers are characterized by warm, saline water, indicating deep groundwater circulation. Garamoon (1996) noted: “The electrical conductivity of the western gravel aquifer exhibits a wide range, where it measured 252  μS/cm in the east and reached 173,000 μS/cm in a sabkha body near Al Khaznah, along Al Ain - Abu Dhabi road. The aquifer has high tritium (3H) close to the eastern mountain ranges, while the well tapping the western part of the aquifer has no or low3H levels. The low carbon­14 (14C) activity in groundwater samples collected from the western part of the aquifer also suggests its old age (15,000 years). The iso-electrical conductivity contours map for the western gravel aquifer indicate that its water is generally fresh and suitable for all uses, despite the salt-water intrusion problems affecting this aquifer in some areas. Saline water source is not only limited to the sea, but salt water from deep zones in the aquifer itself or from nearby saline water under sabkha area can move into the aquifer, increasing salinity and deteriorating water quality. The groundwater in the western gravel is soft in the eastern part of the aquifer and hard to very hard in Al Dhaid, Al Khaznah and along the western coastal region. The SAR values in the northern and eastern parts of the western gravel aquifer is high and groundwater can be harmful to plant and soil, in case this water is used for irrigation. The groundwater along the western part of the western gravel aquifer has high SAR and can be harmful when used for irrigation of traditional crops.

11.2  The Western Gravel Aquifer

385

55o 30'

55o 30'

AL Hayer 24o

Suweyhan

24o

30'

30'

AL Hayer

10 Suweyhan

24o 30'

10

30'

24o

9.0

7.0

AL Khaznah

F

10

UNITED ARAB EMIRATES

00'

5

20 km

AL Wagan

Sr

55o 30'

24o

OMAN

OMAN

1.0

3.0

0

5.

00'

30

0

7.

24o

00'

40

0

9.

24o

15

AL Khaznah

UNITED ARAB EMIRATES

00'

Aloha Al Ain

20

24o

3.0

5.0

5

10 Aloha Al Ain

20 km

AL Wagan

55o 30'

55o 30'

55o 30'

AL Hayer

0.

Suweyhan

30'

24o

24o

30'

30'

24o

Suweyhan

30'

Aloha Al Ain

3

1

Fe

24o

24o

00'

00'

OMAN

UNITED ARAB EMIRATES

AL Khaznah

AL Wagan

20 km

55o 30'

24o 00'

UNITED ARAB EMIRATES

Mn

OMAN

0.2 0.

0.4 0.5

0.1

24o 00'

0.5

0.

AL Khaznah

0.01

Aloha Al Ain

0.03 0.05

24o

5

0.

2

0.

3

AL Hayer

AL Wagan

20 km

55o 30'

Fig. 11.43  Contour maps showing iso-contour lines of fluoride ion, strontium, iron and manganese in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)

11.2.4  Groundwater Evaluation The quality of water determines its potential use for different purposes, depending on specified standards. This part discusses evaluation of groundwater in the western gravel aquifer for domestic, industrial and agricultural purposes. The drinking water must satisfy physical, chemical, biological and radioactive criteria in order to be used by human. Table 17.2 lists the WHO (1984) standards for drinking water, and

386

11  Gravel Aquifers 55o 30'

30'

24o

0.

30'

AL Hayer

Suweyhan

30'

0.1

Aloha Al Ain

05

0.1

0.0

AL Khaznah

0.

15

05

0.

3

0.

0.

0.04 Aloha Al Ain

2

0.

24o

2

Suweyhan

30'

24o

15

05 0.

4

0.0

24o

0.

AL Hayer

25 0 .3

55o 30'

03

0.

AL Khaznah

6

0.0

UNITED ARAB EMIRATES

4

0.0

5

24o

00'

00'

24o 00'

UNITED ARAB EMIRATES 0.

02

5

0. 06

0 0.

24o

OMAN

00'

OMAN

0.03

24o

Cu

20 km

AL Wagan

Pb

55o 30'

55o 30'

55o 30'

0.1

55o 30'

Aloha Al Ain AL Khaznah

2 0.0

24o

30'

30'

24o

Suweyhan

30'

5

24o

0.0

Suweyhan

30'

AL Hayer

0.1 5 0.2

AL Hayer 24o

20 km

AL Wagan

1.0

Aloha Al Ain

0.05

AL Khaznah

0.1

0.5

0.01

0.15

1

24o

24o

24o

00'

00'

00'

Zn

OMAN

UNITED ARAB EMIRATES

AL Wagan

55o 30'

20 km

0.2

Cr

24o 00'

UNITED ARAB EMIRATES

OMAN

0.5

0.

AL Wagan

20 km

55o 30'

Fig. 11.44  Contour maps showing iso-contour lines of copper, lead, zinc and chromium in the western gravel aquifer. (After Garamoon 1996; Rizk et al. 1998)

Fig. 11.47 shows that the groundwater in east Al Ain area is fresh and its TDS content is less than 1000 mg/L. The groundwater of the western gravel aquifer in the middle of Al Ain area is fresh (TDS  =  1000) to brackish (TDS  =  10,000  mg/L), while groundwater in the western part of the western gravel aquifer is saline and has of TDS greater than 10,000 mg/L”. According to Bouwer (1978), water hardness is the sum of calcium (Ca2+) and magnesium (Mg2+) ions, in mg/L of calcium carbonate (CaCO3). Except for ground-

11.2  The Western Gravel Aquifer 54o

53o

56o

55o

N

6

Umm Al Quwain

ARABIAN

GULF

Abu Dhabi

130

132

S A

134

15

17

114 115 116 117 119

UNITED ARAB EMIRATES

133

Bu Hasa

45 38

14

13

Diba

9

10 11 27

16

18

51

85 87 98 124 88 106 108 89 104 125 101 91 107 103 123 100 86 90 105 110 102 92 95 94 99 93 109 111 112 113

128

24˚ 131

7 12

8

30˚N

Al Ain

126

127 129

5

39 44 47 48 28 46 43 49 37 36 29 42 50 41 35 52 40 31 Fujai53 34 20 54 19 33 32 rah 23 21 30 55 26 22 25 Kalba 24 20˚N 56 59 57 67 58 61 68 60 62 71 63 69 72 66 64 73 70 65 74 75 76 77 78 79 96 80 81 84 97 83 82

Ajman Sharjah Dubai

20˚N

121

118 120

24˚

OMAN

122

U D

135

I

137136 Liwa 142

152

23˚

ARAB 53

3 4

Ras Al Khaimah

GULF OF OMAN

o

OM AN

53

30˚N

387

o

140 141 151 139

144

138 143

146 147

145 148

23˚

150 149

50 km

IA

53o

55o

54o

56o

Fig. 11.45  Locations of sampling for isotopes analysis, including the western gravel aquifer in the Al Ain area. (After Rizk et al. 1998; Rizk and Alsharhan 2003)

15

WL

Deuterium (‰)

LM -5

-4

-3

-2

Wadi Al Bih Bu Hasa

10

Jabal Hafit Falajs

Al Ain Liwa

5 -1

0

1

2

3

4

5

-5 -10 -15

B

-20 -25

LMWL = Local Meteoric Water Line LMWL D = 8 18 O+15

Oxygen-18 (‰)

Fig. 11.46  Stable isotopes hydrogen (2H‰) and oxygen (18O‰) water of the UAE, including the western gravel aquifer in the Al Ain area. (After Rizk et al. 1998; Rizk and Alsharhan 2003)

388

11  Gravel Aquifers

A

B

55o 30'

AL Hayer

24o

Suweyhan

30'

24o

24o

30'

30'

55o 30'

Suweyhan

RA

DE

MO

Y

L TE

AL Hayer 24o

D AR

H

30'

R TE

WA

Aloha Al Ain

Aloha Al Ain AL Khaznah

AL Khaznah

24o

00'

00'

RD

A YH

R VE

24o 00'

UNITED ARAB EMIRATES

UNITED ARAB EMIRATES

20 km

AL Wagan

20 km

AL Wagan

55o 30'

C

R

TE

WA

OMAN

24o

00'

OMAN

24o

55o 30'

D

55o 30'

AL Hayer

24o 30'

ER

AT

DW

R HA

Suweyhan

24o

24o

30'

30'

55o 30'

AL Hayer

24o

B

Suweyhan

A

30'

C Aloha

Aloha Al Ain

Al Ain AL Khaznah

24o

24o

00'

00'

00'

OMAN

24o

UNITED ARAB EMIRATES ALWagan 55o 30'

20 km

E

0.05

D

UNITED ARAB EMIRATES

LEGEND A Suitable for all crops B Suitable for some crops C Crops in good drainage soils D Salt - tolerant crops E Harmful for all crops

24o 00'

OMAN

AL Khaznah

ALWagan

20 km

Fig. 11.47  Classification of groundwater in the western gravel aquifer in the Al Ain area, based on TDS (mg/L), total hardness (mg/L), sodium adsorption ratio (SAR) and suitability for irrigation. (After Garamoon 1996; Rizk et al. 1998)

water in the eastern Al Ain area, groundwater in the western gravel aquifer is hard to very hard, as a result of dissolution of carbonate rocks by the low salinity rainwater recharging the aquifer. Evaluation of groundwater suitability for irrigation purposes depends on sodium adsorption ratio (SAR) because sodium reacts with soil and decreases its porosity.

11.2  The Western Gravel Aquifer

389

Specific conductance (µS/cm) at 25° C 100

1000

5000

Sodium adsorption ratio (SAR)

High S3 Medium S2

Poor-Quality Water

20 50

Fair-Quality Water

7

86

79

46 91

19

37 31 250 C1 Low

10

59 87 40 30 77 28 36 102 74 68 83 98

Good-Quality Water

100

39

80

39

Low S1

Sodium (alkali) hazard

V. High S4

30

69

65

750 C2 Medium

64

0 2250

C3 High

78 5000 C4 Very High

Salinity hazard Fig. 11.48  Suitability of water in the western gravel aquifer in the Al Ain area for irrigation in the eastern UAE during June 1994. (After Garamoon 1996)

According to SAR values, the quality of groundwater in the eastern Al Ain area is good and has no harmful effects on plant and soil when used for irrigation (Fig. 11.47). This figure shows that groundwater is fair for irrigation in the middle of the Al Ain area and poor for irrigation western Al Ain area (Figs. 11.30, 11.48 and 11.49).

390

11  Gravel Aquifers

Specific conductance (µS/cm) at 25°C 100

1000

5000

Sodium adsorption ratio (SAR)

High S3

Medium S2

50

Poor-Quality Water 59

16

Fair-Quality Water

66 18

61 40 51 67 57 34

20

64

63 10

29

Good-Quality Water

Low S1

Sodium (alkali) hazard

V. High S4

30

31 69 100

71

250 C1 Low

32 75 70 65 72

66

36

27 33

750 C2 Medium

73

35

0 2250

C3 High

74

5000 C4 Very High

Salinity hazard Fig. 11.49  Suitability of water in the western gravel aquifer in the Al Ain area for irrigation in the eastern UAE during February 1995. (After Garamoon 1996)

References Akram S, Al Mahmoudi A, Ebraheem A, Shetty A (2005) GIS-Based hydrogeological and geophysical studies for groundwater exploration in the Wadi Tawiyean area, UAE. In: Proceedings of the Seventh Gulf water conference on water in the GCC – towards an integrated management, vol 1, pp 247–257 Al Asam MS, Wagner W (1997) Investigation for development of ground water management strategies in the eastern coastal plain of the UAE.  In: Proceeding of the third Gulf water ­conference: towards efficient utilization of water resources in the Gulf, Muscat, Sultanate of Oman, pp 329–339 Al Nuaimi HS (2003) Hydrogeological and geophysical studies on Al Jaww Plain, Al Ain area, UAE: UAE University – Faculty of Graduate Studies, Water Resources program: Unpublished Master Thesis, p 150

References

391

Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region: the Arabian Gulf and adjoining areas. Elsevier Publishing Company, Amsterdam, p 331 Bakhit DW (1998) Environmental and management problems in the hydrology of the United Arab Emirates: (Unpublished Ph.D.), University of South Carolina, pp 9, 16 and 116 Bakhit DW, Narin AEM (1997) A proposed water conservation plan for the Fujairah Emirate. J Fac Sci UAE 9(1):171–201 Bin Braik WNA (1997) Evaluation of groundwater quality in shallow aquifers under cultivated lands al Al Oha area, UAE: UAE University—Faculty of Graduate Studies, Water Resources program. Unpublished Master Thesis Bouwer H (1978) Groundwater hydrology. McGraw-Hills, New York, p 480 Bright DJ, Al Za’afarani M (1997) Estimating total dissolved solids concentration of groundwater using borehole geophysical logs. In: Proceeding of the Third Gulf water conference. Towards efficient utilization of water resources in the Gulf, Muscat, Sultanate of Oman, pp 183–195 Cartwright K, Sherman F (1972) Electrical earth resistivity surveying in landfill investigations. In: 10th Annual engineering and soils engineering symposium, Moscow, ID Clark ID (1984) Groundwater resources in the Sultanate of Oman  – origin, circulation times, recharge processes and paleoclimatology. Isotopic and geochemical approaches. Ph. D. Thesis, Universite de Paris-Sud, p 264 Ebraheem AM, Hamburger MW, Bayless ER, Krothe NC (1990) A study of acid mine drainage using earth resistivity measurements. Ground Water 28(3):361–368 Ebraheem AM, Senosy MM, Dahab KA (1997) Geoelectrical and hydrogeochemical studies for delineating groundwater contamination due to salt-water intrusion in the Northern Part of the Nile Delta, Egypt. Ground Water 35(2):216–222 Ebraheem AM, Garamoon HK, Rizk ZS, Khalil MF, Al Matari AS, Al Mulla MM, Shetty A (2015) Application of two-dimensional earth resistivity imaging for groundwater exploration and assessment of salt-water intrusion problem in Wadi Al Ruheib and Wadi Al Basserah drainage basins, northern United Arab Emirates. J Appl Geol Geophys 3(6):34–45 Edwards LS (1977) A modified pseudosection for resistivity and IP. Geophysics 42(5):1020–1036 El Mahmoudi AS, Al Nuaimi H, Sherif M (2004) Geophysical and hydrological investigations of the quaternary aquifer at Al Jaww Plain, Al Ain area, UAE.  Environ Eng Geophys Soc 9(1):17–28 El Shami F (1990) Hydrochemical classification of the groundwater of the Wadi Dibba in the Northeastern part of the UAE. J Fac Sci UAE 2/1:7–29 El Shami F (1991) Water type variation during pumping test, Al Jaww Plain, Southeast of Al Ain the UAE. GeoJournal 25(/4):383–386 Erikson E (1983) Stable isotopes and tritium in precipitation. In: Guidebook on nuclear techniques in hydrology, Technical report series no. 91. IAEA, Vienna, pp 19–33 Freeze RA, Cherry JA (1979) Groundwater. Prentice Hall, Englewood Cliffs, p 604 Garamoon HK (1996) Hydrogeological and geomorphological studies on the Abu Dhabi  – Al Ain  – Dubai rectangle, United Arab Emirates. Ph. D.  Thesis, Ain Shams University, Cairo, Egypt, p 277 Gibb and Partners (1970) Water resources survey, supplement to interim report, subsurface investigations in Al Ain area. Department of Development and Public Works, Abu Dhabi Hadley DG, Menges CM, Woodward D, Buchean I, Parkla G, Poster C (1991) Seismics in the search for water in the U. A. E. Middle East Well Eval Rev 10:44–46 Haeni FP, Placzek G (1991) Use of processed geophysical data to improve the delineation of infilled scour holes at bridge piers. In: Expanded abstracts with biographies, SEG 61st annual international meeting, Houston, Texas, November 10–14, 1991. Houston, Society of Exploration Geophysicists, pp 549–552 Haeni FP, Placzek G, Trent RE (1992) Use of ground-penetrating radar to investigate infilled scour holes at bridge foundations. In: Hanninen P, Autio S (eds) Fourth International Conference on Ground Penetrating Radar, Rovaniemi, Finland, June 8–13, proceedings: geological survey of Finland special paper 16, pp 285–292

392

11  Gravel Aquifers

Hantush MS (1962) Aquifer tests on partially penetration wells. Am Soc Civ Eng Trans 127(1):284–308 Hem JD (1985) Study and interpretation of chemical characteristics of natural water. In: U S geological survey water supply paper no 1473, p 363 Hounslow AW (1995) Water quality data analysis and interpretation. CRC Press Inc./Lewis Publishers, New York, p 397 Hunting Geology and Geophysics Ltd (1979) Report on a Mineral Survey of the UAE, 1977–1979, Northern Mountains Program, v. 1—Geological Map of the UAE. Ministry of Petroleum and Mineral Resources, Government of the UAE, p 42 Hyde LW (1992) Interregional advisory mission of water resources management. United Nations Department of Technical Cooperation for Development, Abu Dhabi Emirate, p 86 Hydroconsult (1978) Reconnaissance report and development proposals, Abu Dhabi, UAE, eastern region water resources. Government of Abu Dhabi, Ministry of Petroleum and Mineral Resources report, p 126 Jacob CE (1946) Drawdown test to determine the effective radius of artesian well. Trans Am Soc Civ Eng 112(1):1047–1064. paper no. 2321 Jorgensen DG, Petricola M (1994) Petrophysical analysis of geophysical logs of the National Drilling Company  – U.  S. Geological survey groundwater research project for Abu Dhabi Emirate, UAE: U.S. Geological Survey Water Supply Paper no. 2417 Jorgensen DG, Petricola M (1995) Research borehole-geophysical logging in determining geohydrologic properties. Groundwater 33(4):589–596 Khalifa MA (2004) Hydrogeologic setting and characterization of the aquifer system in Al Wagen area, South Al Ain, UAE. United Arab Emirates University, Faculty of Graduate Studies, Water Resources Program, Unpublished Master Thesis Loke MH (1997) Electrical imaging surveys for environmental and engineering studies – a practical guide to 2D and 3D surveys. University Sains Malaysia, Penang. unpublished short training course lecture notes Nasr MA (1997) Application of the Eden-Hazel method for determining transmissivity from step-­ test recovery data. In: Proceeding of the Third Gulf water conference – towards efficient utilization of water resources in in the Gulf, Muscut, Sultanate Oman, pp 209–217 Osterkamp WR, Lane LJ, Menges CM (1995) Techniques of groundwater recharge estimate in arid/semi-arid areas, with example from Abu Dhabi. J Arid Environ 31:349–369 Rainwater FA, Thatcher LL (1960) Methods for collection and analysis of water samples. In: U. S. geological survey water supply paper no. 1454, Washington, p 1–301 Rizk ZS (2014) Determining the sources of nitrate pollution of the Liwa Quaternary aquifer in the United Arab Emirates. In: WSTA 11th Gulf water conference, water in GCC. Towards efficient management, 20–22 October 2014, Muscat, Sultanate of Oman, pp 120–136 Rizk ZS, Alsharhan AS (1999) Application of natural isotopes for hydrogeologic investigations in United Arab Emirates. In: Proceedings of the fourth Gulf water conference, Manama, Bahrain, pp 197–228 Rizk ZS, Alsharhan AS (2003) Water resources in the United Arab Emirates. In: Alsharhan AS, Wood WW (eds) Water management perspectives: evaluation, management and policy. Elsevier Science, Amsterdam, pp 245–264 Rizk ZS, El-Etr HA (1997) Hydrogeology and hydrogeochemistry of some springs in the United Arab Emirates. Arab J Sci Eng 22(1C):95–111 Rizk ZS, Garamoon HK, El-Etr HA (1998) Morphometry, surface runoff and flood potential of major drainage basins of Al Ain area, United Arab Emirates. Egypt J Remote Sens Space Sci 1(1):391–412 Rizk ZS, Garamoon HK, Al Matari AS, Khalil MF, Ebraheem AM (2015) Application of earth resistivity, hydrogeochemistry and isotope hydrology methods for assessment of groundwater recharge in two drainage basins in northeastern United Arab Emirates. J Appl Geol Geophys 3(3):1–13 Sasaki Y (1992) Resolution of resistivity tomography inferred from numerical simulation. Geophys Prospect 40:453–464

References

393

Sherif M, El Mahamoudi A, Garamoon H, Kacimov A, Akram S, Ebraheem A, Shetty A (2005) Geoelectrical and Hydrogeochemical studies for delineating seawater intrusion in the outlet of Wadi Ham, UAE. Environ Geol 49(4):536–551 Silva E (1997) Variable hydraulic responses observed in the alluvial aquifer eastern Abu Dhabi Emirate. In: Proceeding of the third Gulf water conference—towards efficient utilization of water resources in in the Gulf, Muscat, Sultanate Oman, pp 197–207 Symond RB, Robledo AR, Al Shateri HH (2005) Use of environmental traces to identify and date recent recharge to the surgical aquifer of Northern Abu Dhabi Emirates, UAE. In: Proceedings of the seventh Gulf water conference on water in the GCC – towards an integrated management, Kuwait, vol 1, pp 471–486 Telford WM, Geldart LP, Sheriff RE (1990) Applied geophysics. Cambridge University Press, Cambridge Theis CV (1935) The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using ground water storage. Am Geophys Union Trans 16:519–524 Toth J (1963) A theoretical analysis of groundwater flow in small drainage basins. J Geophys Res 68:4795–4812 Toth J (1980) Cross-formational gravity flow groundwater: a mechanism of the transport and accumulation of petroleum (the generalized hydraulic theory of petroleum migration). In: Roberts WH, Cordell RJ (eds) Problems of petroleum migration, AAPG studies in geology, vol 10. The American Association of Petroleum Geologists, Tulsa, pp 121–167 Toth J (1986) Post-paleocene evolution of regional groundwater flow systems and their relation to petroleum accumulations, Taber Area, Southern Alberta, Canada. Bull Can Petrol Geol 34(3):339–363 WHO (1984) WHO guidelines for drinking water quality. Volume 1, recommendations. World Health Organization, Geneva, p 130 Woodward DG (1994) Contributions to a shallow aquifer study by reprocessed seismic sections from petroleum exploration surveys, eastern Abu Dhabi, United Arab Emirates. J Appl Geophys 31(1–4):271–289 Woodward DG, Menges CM (1991) Application of uphole data from petroleum seismic surveys to ground water investigations, Abu Dhabi, United Arab Emirates. Geoexploration 27:193–212

Chapter 12

Liwa Quaternary Sand Aquifer

Abstract  This chapter investigates the hydrogeology and hydrogeochemistry of the “Liwa Quaternary sand aquifer” in the western UAE. The results of an investigation uncovered the presence of a fresh groundwater lens south of the Bu Hasa Oil Field. A similar aquifer is already known to exist in the area between Madinat Zayed and Liwa Oasis. The aquifers in both areas have similar hydraulic properties, water chemistry and isotopic contents. For this reason, both aquifers are named by the authors the Liwa Quaternary sand aquifer. The Liwa Quaternary sand aquifer is composed of two fresh/groundwater mounds in Liwa and Bu Hasa and constitutes a relic of an older and larger aquifer system formed during the pluvial periods that affected the northwestern part of Liwa Oasis between 7000 and 5000 years ago. A large mound of an oval shape, 120-­ km long and 40-km wide, extends between the Liwa Crescent and Madinat Zayed, and another small elliptical mound, with an average diameter of 40  km, occurs between Bu Hasa and Habshan areas. In Liwa, the groundwater depth is 50 m, and in Bu Hasa the groundwater depth is 24–52 m. The aquifer’s hydraulic parameters are: “hydraulic conductivity (K) is 2.3–8.5  m/d, transmissivity (T) is 200–650  m2/d and specific capacity (SC) is 40–90  m2/d. The aquifer’s saturated thickness varies from 175 m between Bu Hasa and Madinat Zayed. The Liwa Quaternary sand aquifer is free (Sy = 0.1–0.3) and heterogeneous (hydraulic gradient = 0.001–0.01)”. The groundwater in the Liwa Quaternary sand aquifer is: “Fresh where the total dissolved solids (TDS) is ≤1000  mg/L, saline where the TDS is ≥10,000  mg/L, mostly hard (TH > 200 mg/L) and unsuitable for drinking or domestic uses. The concentrations of all cations and anions (except HCO3−) increase from the center of each fresh water mound outwards in all directions”. The average values of sodium adsorption ratios (SARLiwa  =  24 and SARBu Hasa  =  40) and electrical conductance (ECLiwa = 13,016 μS/cm and ECBu Hasa = 4588 μS/cm) indicates that the groundwater of the Liwa Quaternary sand aquifer can harm conventional crops when used for irrigation. The concentrations minor cations (NO3− and F−) and trace elements (B, Cr and Zn) are higher than the WHO limits for drinking water. Based on analysis of groundwater chemistry and natural isotopes (2H, 3H, 18O and 14 C), the authors identified and characterized regional, intermediate and local ground© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_12

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water-flow systems in the UAE. The Liwa-Bu Hasa area has a regional groundwaterflow system characterized by an old groundwater of Cl type, low c­ arbon-­14 (14C) and tritium (3H) activities. This finding supports the proposed past pluvial periods indicated in previous studies used radiocarbon dating of lacustrine deposits in the Liwa area. The high level of stable isotopes (2H and 18O) in the Liwa Quaternary sand aquifer indicates high evaporation before recharge. Both isotopes are identical in the aquifer at Bu Hasa Oil field and Liwa Oasis, reflecting the similarity of groundwater characteristics in both areas. The absence of 3H and low level of 14C in groundwater samples collected from of the aquifer suggest old-age groundwater and lack of recharge in the present time.

12.1  Introduction About three-fourths of the surface area of the UAE is covered by Quaternary sands. Elevation of dunes above sea level increases gradually from a few m close to the coast to 250 m above the ground surface in Liwa Oasis, which forms the northeastern tip of “Rub’ al Khali” (empty quarter) desert in the Arabian Peninsula (Embabi 1991). Quaternary sand aquifers, despite their extensive geographic reach, are the least studied, especially with respect of their hydrogeologic conditions and groundwater potentialities. Exploration of these important aquifers in the Western Region of the country may lead to discovery of fresh-groundwater mounds such as those uncovered in Liwa Oasis and Bu Hasa area (Rizk et al. 1997). The depth to groundwater in the Quaternary sand aquifers varies between  50 m in Liwa area. Rizk and Alsharhan (2003) defined the aquifer’s location as: “The Liwa Quaternary sand aquifer occurs in the south central part of the UAE, bounded

Photo 12.1  Quaternary sand aquifer in the western Sharjah Emirate, where groundwater lies less than 2 m below the ground surface

12.1 Introduction

397

54o

53o

52o

56o

55o

Ras Al Khaimah Dibba

Umm Al Qaiwin

Arabian

Ajman Sharjah Dubai

Gulf

Fujairah

Gulf of Oman

Latitudes 22° 45′ and 23° 45’ N and Longitudes 53° 00′ and 54° 30′ E, located between Habshan oil field in the north, the UAE border with Saudi Arabia in the south, Asab oil field in the east and Bu Hasa oil field in the west (Fig. 12.1)”.

25o

25o

Abu Dhabi Al Ain 24o

24o

UNITED

ARAB

EMIRATES

Madinat

OMAN



 Zayad



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SAUDI ARABIA 54o

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16 18

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Ardah SAUDI ARABIA

Sahil

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23 o 00'

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11 GWP 139 12

BU 121 GWP 143

GWP 95

20

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Mizairaa 19

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SH2 SH9 SH 3 SH10 SH11 SH1 SH7 SH6 SH 2 4 SH5 SH8

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PS GWP

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55o o

LWS

Asab

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LQ  Main Town

GWP 98

A –A’ Geological

24

25

26 27

Cross Section Wells Sampled for Grain-Size Analysis

Hamim 28

GWP 96

A’

40 km

Fig. 12.1  Roads, main cities and water wells used for investigating the sand aquifer at Liwa Oasis and Bu Hasa areas, in the western UAE. A-A’ is the trace of the geologic cross section illustrated in Fig. 12.2

398

12  Liwa Quaternary Sand Aquifer

12.2  Geologic Setting The stratigraphic column in the western UAE was subdivided, based on petrophysical studies, into 4 units, from top to base (Imes et al. 1994): the undifferentiated Quaternary sands, the Lower Fars Formation, an Oligo–Miocene clastics unit and the Dammam Formation (Fig. 12.2). Wood et al. (2003) divided the water-bearing units at Liwa area into “two main stratigraphic units; the Tertiary sediments and the Pleistocene-Holocene deposits”.

12.2.1  Tertiary Sediments Alsharhan et al. (2001) described the Tertiary sediments in the Liwa area as: “the oldest and deepest sediments tapped by shallow water wells in the Bu Hasa Oil Field and Liwa Oasis are the Eocene carbonates of the Dammam Formation (Hassan and Al Aidarous 1985), which consists of nummulitic limestone with mudstone and sandstone interbedded (GeoConsult 1985). Alsharhan et  al. (2001) described the Dammam Formation as the main fresh water bearing aquifer in Bahrain, Qatar and Saudi Arabia. But, the Dammam carbonate in the UAE store brackish to saline groundwater and has poor hydraulic properties. A METERS

100 50

SEA LEVEL

BU 336

A' RFACE

LAND SU

GWP 139

GWP 104

GWP 95

GWP 97

GWP 96

WATER TABLE

Domestic water-supply aquifer

QUARTERNARY LIWA AQUIFER

0 50 100

Confining layer LOWER FARS FORMATION

150 200 250

Wastewater disposal aquifer

MIOCENE CLASTICS AQUIFER

300 350 400

DAMMAM FORMATION Brine production aquifer

450 500

Fig. 12.2  Lithologic cross section in the Liwa Oasis and Bu Hasa oil field in the western UAE (including the Liwa Quaternary sand aquifer). (After Imes et al. 1994)

12.2 Geologic Setting

399

The Dammam Formation is unconformably overlain by a 120 m thick Miocene clastics consist of clay, with sandstone and limestone interbeds. The clastic unit is overlain by a layer of anhydrite (GeoConsult 1985). The Oligo-Miocene Lower Fars Formation overlies the anhydrite bed, has an average thickness of 200 m at Liwa and 150 m at Bu Hasa and consists of mudstone, marl and siltstone, with carbonate and evaporite interbeds (Hassan and Al Aidarous 1985). Figure 12.2 shows that the Lower Fars Formation acts as a confining layer, preventing vertical movement of groundwater between the Miocene Clastics aquifer and Liwa Quaternary sand aquifer because it has a very low hydraulic conductivity. However, the upper section of the formation exhibits a major change in lithology indicated by density and neutron logs (Imes et al. 1994)”.

12.2.2  Quaternary Deposits In Liwa and Bu Hasa areas, Imes et al. (1994) described the Quaternary deposits as: “Pleistocene–Holocene sands overlying the Lower Fars Formation. These sands are clay-free and are composed of fine to medium-grained quartz, carbonates, evaporites and heavy minerals. Surface sabkha deposits are composed of salty sand and silt forming the low lying areas between sand dunes, predominantly on the southern side of the Liwa Crescent. The Quaternary deposits represent the main aquifer in Liwa and Bu Hasa areas. The aquifer has moderate hydraulic properties and has an average thickness of 110 m. Field sampling was conducted during the period 1996–1999 for investigating the Liwa Quaternary sand aquifer in western UAE. Field-measured parameters showed that groundwater between Madinat Zayed and Liwa Oasis is fresh and indicated the presence of similar aquifer in the Bu Hasa Oil Field (Fig. 21.1)”. The authors named the aquifer system at the Liwa Oasis and Bu Hasa Oil Field the “Liwa Quaternary sand aquifer” because of the identical hydraulic properties, groundwater chemistry and activities of natural isotopes in groundwater samples collected from both areas. The results of hydrogeological and hydrogeochemical investigations identified a fresh-groundwater lens at Bu Hasa Oil Field, and a similar feature in the area between Madinat Zayed and Liwa Oasis, belonging to the Liwa Quaternary sand aquifer. The two fresh-groundwater mounds in Liwa and Bu Hasa represent a relic of an older and larger aquifer system formed during the pluvial periods affected the northwestern part of Liwa Oasis between 7000 and 5000 years ago (McClure 1978; Clark 1984; Clark and Fritz 1997; Wood and Imes 1995). The Liwa Quaternary sand aquifer comprises two fresh groundwater mounds in Liwa and Bu Hasa and represents a relic of an older and larger aquifer system formed during the pluvial periods affected the northwestern part of Liwa Oasis between 7000 and 5000 years ago. The large mound has an oval shape, 120 km long and 40 km wide and extends between Liwa Crescent and Madinat Zayed. The other mound is smaller, has an elliptical shape, with an average diameter of 40 km and is located between Bu Hasa and Habshan areas.

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12  Liwa Quaternary Sand Aquifer

In Liwa, Wood et al. (2003) described the aquifer’s hydraulic properties as: “The groundwater depth in Liwa varies between  50 m, and in Bu Hasa the groundwater depth varies between 24 and 52 m. The aquifer’s transmissivity (T) is 200–650 m2/d, specific capacity (SC) is 40–90 m2/d and hydraulic conductivity (K) is 2.3–8.5 m/d. The aquifer’s saturated thickness increases from 175 m between Bu Hasa and Madinat Zayed. The Liwa Quaternary sand aquifer is free and heterogeneous, its specific yield is 0.1–0.3 and hydraulic gradient is 0.001–0.01, respectively”.

12.3  Hydrogeology The Liwa Quaternary sand aquifer, according to Wood et  al. (2003) is: “largely composed of quartz, equal amounts dolomite and calcite and small proportions of feldspar, anhydrite and heavy minerals (Hadley et al. 1998). The laboratory evaluation of average porosity for a few samples from the aquifer averaged 38% with little variation. This average is within the porosity range of fine eolian sand, which typically varies between 35 and 40% (Driscoll 1986)”. The average thickness of the Quaternary deposits in Liwa and Bu Hasa areas is 110 m. These deposits represent the topmost unit in the stratigraphic column, possess moderate hydraulic properties and constitute the Liwa Quaternary sand aquifer. These aquifer-forming sands are well-sorted, clean and fine- to medium-grained (0.16–0.22  mm). The aquifer unconformably overlies the Lower Fars Formation (Fig. 12.2). Surface sabkhas are composed of salty sand and silt occupying the low lying areas between sand dunes, predominantly on the southern side of the Liwa Crescent. Because the size and uniformity of sand affect its hydraulic conductivity, Wood et al. (2003) conducted grain-size analysis of 20 sand samples from the Liwa area and determined the effective uniform size (d50) and aquifer’s hydraulic conductivity (K) and uniformity coefficient (Cu). Figure 12.3 shows the results of grain-size analysis of six sand samples. The effective grain size for the sand dunes in the Liwa aquifer varies between 0.17 and 0.24  mm, the uniformity coefficient (Cu), calculated by Garg’s (1978) equation: Cu = d60/d10, ranges 1.64–3.33 and averages 2.41. Taylor (1948) applied the equation: K = C∗(d10)2, for calculating the hydraulic conductivity (K) of a fairly uniform sand, “where C is a constant = 850 for sand samples with Cu 50,000 mg/L

25o 40’

25o 40’

e

ac

- rf er te at r In aw te Se dwa n ou

r

G

Ajman Emirate

5 km

Sharjah Emirate

25o 35’

55o 45’

55o 50’

55o 55’

25o 35’

56o 00’

Fig. 18.24  Isosalinity contour map of groundwater in the Ajman area. (After Al-Hogaraty et al. 2008

0

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Sharjah Emirate

25o 45’

b DO

d Mg 2+

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pH

18  Groundwater: Quality Degradation and Water Pollution

0

582

55o 55’

25o 40’

Al Heliw

Fig. 18.25  Contour maps of the hydrochemical parameters pH (a), TDS (b), TH (c), DO (d), and concentrations of major cations calcium (e), magnesium (f), sodium (g) and potassium (h) ions in groundwater at Ajman area. The dotted zone suffers from saltwater intrusion

18.7 Quaternary Sand Aquifer in Ajman Emirate

HCO3

55o 55’

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Sharjah Emirate

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583

SO42-

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Al Heliw 55o 55’

Fig. 18.26  Contour maps of the anions bicarbonate (a), sulphate (b), chloride (c) and nitrate (d) ions, in addition to trace elements iron (e), lead (f), cadmium (g) and chromium (h) elements in groundwater of the in the Ajman area. The dotted zone suffers from saltwater intrusion

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18  Groundwater: Quality Degradation and Water Pollution

The hydrogen-ion concentration (pH) contours illustrate that the pH increases from east to west (Fig. 18.25). The increase in pH towards the Arabian Gulf reflects the influence of seawater intrusion in the aquifer. Al Hogaraty et al. (2008) measured the lowest dissolved oxygen (DO) concentration in the nearby sewage-­ disposal area (Figs. 18.22 and 18.25). Rizk and Alsharhan (2003) pointed out the increasing concentration of major ions in groundwater of the Quaternary sand aquifer in the western UAE. The seawater–groundwater interface in the western part of the Al Jarf area was found to coincide with the sharp rise in concentration of all groundwater-dissolved ions (Figs. 18.25 and 18.26). Areas of high levels of dissolved chemicals in the aquifer are reflections of aquifer contamination from natural and human-related sources on the land surface. Contour maps showing iso-concentrations of magnesium (Mg2+), calcium (Ca2+), potassium (K+) and sodium (Na2+) ions are illustrated in Fig. 18.25. Iso-­ concentration contour maps of sulphate (SO42−), bicarbonate (HCO3−), nitrate (NO3−) and chloride (Cl−) ions in groundwater in the Ajman area are also displayed in Fig. 18.25. The HCO3− content, in contrast to all other ions, decreased in the direction of groundwater flow (Hounslow 1995; Rus et al. 2006). Al Hogaraty et  al. (2008) constructed iso-concentration contour maps for the trace elements lead (Pb), iron (Fe), chromium (Cr), cadmium (Cd), Copper (Cu), manganese (Mn), zinc (Zn) and nickel (Ni). These maps are presented in Fig. 18.26. Results show that trace elements in the aquifer were more responsive to humanrelated pollution sources than natural sources. High lead and iron and ­chromium levels were measured close to sewage-water disposal site (Figs. 18.20 and 18.26) and centers of urban activities (Figs. 18.20 and 18.26). Hydrochemical cross sections illustrate the effect of human activities and natural conditions on groundwater quality (Figs. 18.21 and 18.27), while Fig. 18.27c shows the natural and human activities causing groundwater pollution. Most desalination plants use the reverse-osmosis (RO) method for desalination of brackish and saline groundwater (Fig. 18.21). According to ESCWA (2001 and 2005), the efficiency and service life of the RO membranes depends mainly on the salinity of the feedwater. The actual production of desalination plants receiving high salinity feedwater is lower than their initial design capacities, which leads to precipitation and membrane fouling problems in RO plants (Dabbagh et al. 1994; Al Mutaz and Al Sultan 1997; Dolatyar and Gray 2000).

18.7.5  Anthropogenic Factors Groundwater pollution in the Ajman area can be linked, in part, to the rapid urban development and extensive human-related activities during the last decade Al Hogaraty et al. (2008). In some instances, the wide expansion of urban development

18.7 Quaternary Sand Aquifer in Ajman Emirate

585

has resulted in disposal of waste in an uncontrolled and unregulated manner. In addition to agricultural activities, seepage of wastewater from these pollution sources can cause large amounts of pollutants to reach groundwater.

South

1500

a

CI

Chloride

SO42-

Sulphate

-

CO32- + HCO3-

Carbonate + Bicarbonate

Cations

Concentration (meq/ L)

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North

1000

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A’

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SO42-

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Seawater - Groundwater Interface

nd

a Loose s

B’

120

le r Tab Wate

DIB-1

East ll Landfi

C

Leachate

Quaternary Sand Aquifer Contaminants Plume

Fig. 18.27  Hydrochemical cross section illustrating the contribution of natural processes and human activities to groundwater pollution

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18  Groundwater: Quality Degradation and Water Pollution

References Al Asam MS (1994) Dams in the United Arab Emirates and their role in groundwater recharge. In: Proceedings of the second Gulf water conference, Manama, Bahrain, WASTA, pp 203–218 Al Asam MS (1996) UAE water resources use in agriculture and conservation. International Desalination Association (IDA) conference of Desalination, Abu Dhabi, IDA, pp 625–37 Al-Hogaraty EA, Rizk ZS, Garamoon HK (2008) Groundwater pollution of the quaternary aquifer in northern United Arab Emirates. Water Air Soil Pollut 190:323–341 Ali MY, Watts AB, Searle MP (2013) Seismic stratigraphy and subsidence history of the United Arab Emirates (UAE) rifted margin and overlying foreland basins. In: Al Hosani K et al (eds) Lithosphere dynamics and sedimentary basins. The Arabian plate and analogues, frontiers in earth sciences. Springer, Berlin/Heidelberg Al-Katheeri ES, Howari FM, Murad MM (2008) Hydrogeochemistry and pollution assessment of quaternary-tertiary aquifer in the Liwa area, United Arab Emirates. Environ Earth Sci 59:581–592 Al Mutaz IS, Al Sultan B(1997)Operation characteristics of Maufouha reserve osmosis plants: The IDA World Congress on Desalination and Water Reuse, Madrid, Spain, p 25 Al Nuaimi HS (2003) Hydrogeological and geophysical studies on Al Jaww Plain, Al Ain area, UAE: UAE University—Faculty of Graduate Studies, Water Resources program: Unpublished Master Thesis, p 150 Alsharhan AS (1989) Petroleum geology of the United Arab Emirates. J Pet Geol 12:253–288 Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region: the Arabian Gulf and adjoining areas. Elsevier Publishing Company, Amsterdam, p 331 Al Wahedi AA (1997) Application of hydrogeochemistry and groundwater modeling techniques for water-resources management of Wadi Al Bih Drainage Basin, United Arab Emirates. Unpublished M. Sc. Thesis, UAE University, Al Ain, United Arab Emirates Andersen LJ, Kristiansen H (1984) Nitrate in groundwater and surface water related to land use in the Karup Bain, Denmark. Environ Geol 5:207–212 APHA (1995) Standard methods for examination of water and waste water, 19th edn. APHA 2540 C, Washington, DC Appelo CAJ, Postma D (1999) Geochemistry, groundwater and pollution. Balkema, Rotterdam, p 636 Azhar A (2000) Problems of developing world’s water networks. In: IV International conference. Water supply and water quality, Krakow, Poland, pp 1229–1233 Baker AMJ (1981) Accumulators and excluders: strategies in the response of plants to trace metals. J Plant Nutr 3:643–654 Barnes CL, Jacobson G, Smith GD (1992) The origin of high-nitrate groundwaters in the Australian arid zone. J Hydrol 137:181–197 Becker MF, Bruce BW, Pope LM, Andrews WJ (2002) Groundwater quality in the central High Plains aquifer, Colorado, Kansas, New Mexico, Oklahoma, and Texas, 1999. U.S. Geological Survey Water-Resources Investigations Report 02–4112, p 64 Berna C, Lang T, Goodwin G, Holmes E (2011) Developing a measure of interpretation bias for depressed mood: an ambiguous scenarios test. Personal Individ Differ 51(3):349–354 Bleifuss PS, Hanson GN, Schoonen M (2000) Tracing sources of nitrate in the Long Island aquifer system. On line, p 27 Böhlke JK (2002) Groundwater recharge and agricultural contamination. Hydrogeol J 10:153–179 Brook MC, Dawoud M (2005) Coastal water resources management in the coastal zones of United Arab Emirates. Symposium on Integrated Coastal Zone Management, Abu Dhabi UAE Bruce BW, Becker MF, Pope LM, Gurdak JJ (2003) Groundwater quality beneath irrigated agriculture in the central High Plains aquifer, 1999–2000. U.S. Geological Survey Water-Resources Investigations Report 02–4219, p 39 Chauret C, Springthorpe S, Sattar S (1999) Fate of Cryptosporidium oocysts, Giardia cysts, and microbial indicators during waste water treatment and anaerobic sludge digestion. Can J Microbiol 45(3):257

References

587

Clark ID, Fritz P (1997) Environmental isotopes in hydrogeology. CRC, Florida, p 328 Clesceri LS, Greenberg AE, Eaton AD (1998) Standard methods for the examination of water and waste water, 20th edn. American Public Health Association, Washington Cox PA (1991) The elements—their origin, abundance and distribution. Oxford University Press, Oxford Dabbagh T, Sadler P, Al-Saqabi A, Sadeqi M (1994) Desalination: an emergent option. In: Rogers P, Lydon P (eds) Water in the Arab World  – perspectives and prognoses, vol 8. Harvard University, Division of Applied Sciences, Cambridge, pp 203–242 Dawoud MA, Sallam OM, Abdelfattah MA (2012) Treated wastewater management and reuse in arid regions: Abu Dhabi Case Study. In: The 10th Gulf water conference, Doha, Qatar, pp 732–752 Dolatyar M, Gray TS (2000) Water politics in the Middle East: a context for conflict or cooperation? Macmillan Press Limited, Basingstoke, p 243 Ediger RD (1973) A review of water analysis by atomic absorption. At Absorption Newsl 12:151 El dougdoug A (1993) Origin of unconformity-bound celestite mineralization, Jebel Hafit, Al Ain area, United Arab Emirates. M.E.R.C. Ain Shams Univ. Earth Sci Ser 7:209–222 Electrowatt (Electrowatt Engineering Services Ltd) (1980) Wadi Ham dam for groundwater recharge and loss prevention. Preliminary Rep., Ministry of Environment and Water, Dubai, UAE Electrowatt (Electrowatt Engineering Services Ltd) (1981) Wadi Ham dam and groundwater recharge facilities. Volume I Design, Ministry of Environment and Water, Dubai, UAE Elmahdy SI, Mohamed MM (2012) Topographic attributes control groundwater flow and groundwater salinity of Al Ain, UAE. A prediction method using remote sensing and GIS. J Environ Earth Sci 2(8):1–13 EPA (Environmental Protection Agency—USA) (1993) National interim primary drinking water regulations, part 141. Fed Regist 40(248):59566–59588 EPA (United States Environmental Protection Agency) (2006) Drinking water regulations and health advisories. Environmental Protection Agency, Washington, DC, p 12 Enghag P (2004) Encyclopedia of the elements – technical data, history, processing, applications. Wiley-VCH Verlag GmbH and Co. KgaA, Weinheim ENTEC (Entec Europe Limited) (1996) Survey on groundwater recharge and flow in Wadi Ham, vol 1. Ministry of Environment and Water, Dubai ESCWA (2001) Water desalination technologies in the ESCWA member countries: United Nations. New York, p 177 ESCWA (2005) Development of frameworks to implement national strategies of integrated water resources management in the ESCWA countries: United Nations, New York, p 94 Etiope G (2015) Natural gas seepage. The Earth’s hydrocarbon degassing. Springer, Cham, p 199 Etiope G, Judas J, Whiticar MJ (2015) Occurrence of abiotic methane in the eastern United Arab Emirates ophiolite aquifer. Arab J Geosci 8:11345–11348 Etiope G, Schoell M (2014) Abiotic gas: atypical but not rare. Elements 10:291–296 FAO (1970) Physical and chemical methods of soil and water analysis. Soil Bull 10:236–238 Fetter CW (1988) Applied hydrogeology, 2nd edn. Macmillan Publishing Company, New York, p 592 Freeze RA, Cherry JA (1979) Groundwater. Prentice-Hall, Englewood Cliffs, p 604 Fritz P, Clark ID, Fontes JC, Whiticar MJ, Faber E (1992) Deuterium and 13C evidence for low temperature production of hydrogen and methane in a highly alkaline groundwater environment in Oman. In: Kharaka YK, Maest AS (eds) Proceedings of 7th international symposium on water-rock interaction: low temperature environments, vol 1. Balkema, Rotterdam, pp 793–796 Gill R (1989) Chemical fundamentals of geology, 2nd edn. Chapman and Hall, London, p 290 Gosselin DC (1991) Bazile Triangle groundwater quality study. Lincoln, Conservation and Survey Division of the University of Nebraska Water Supply Paper 68, p 29 Hem JD (1985) Study and interpretation of chemical characteristics of natural water: U.  S. Geological Survey Water Supply Paper no. 1473, p 363

588

18  Groundwater: Quality Degradation and Water Pollution

Hounslow AW (1995) Water quality data analysis and interpretation. CRC Press Inc./Lewis Publishers, New York, p 397 IWACO (1986) Ground water study. Drilling of deep water wells at various locations in the UAE. Internal Rep., Ministry of Environment and Water, Dubai, UAE Jenden PD, Hilton DR, Kaplan IR, Craig H (1993) Abiogenic hydrocarbons and mantle helium in oil and gas fields. In: Howell D (ed) Future of energy gases, vol 1570. USGS Prof Pap, Washington, DC, pp 31–35 Kansas Geological Survey (1990) Geologic map of the United Arab Emirates (scale 1:1,000,000). U. S. Geological Survey: Miscellaneous geologic investigations map I – 270 A, The University of Kansas, Kansas, USA Keller AE (2002) Environmental geology, 2nd edn. Prentice Hall, Inc, Upper Saddle River Khalifa MA (2003) Geohydrology and the source of flowing well water in Al-Neima area, Al. Abu Dhabi Emirate, UAE, National Drilling Company and United States Geological Survey, p 9 Lowrence AR, Foster SSD (1987) The pollution threat from agricultural pesticides and industrial solvents. BGS hydrogeology report, 87–2 Madison RJ, Brunett JO (1983) Overview of the occurrence of nitrate in groundwater of the United States. In: National water summary 1984—hydrologic events, selected water-quality trends, and groundwater resources. U.S. Geological survey water-supply paper 2275, pp 93–105 McMahon PB (2001) Vertical gradients in water chemistry in the central High Plains aquifer, southwestern Kansas, and Oklahoma panhandle, 1999: U.S.  Geological Survey Water-Resources Investigations Report 01–4028, p 35 McMahon PB, Böhlke JK (2006) Regional controls on the isotopic composition of nitrate in groundwater, High Plains, USA. Environ Sci Technol 40(9):2965–2970 Mengis M, Walther U, Bernasconi SM, Wehrli B (2001) Limitations of using δ18 O for the source identification of nitrate in agricultural soils. Environ Sci Technol 35(9):1840–1844 Ministry of Communications (1996) U.A.E.  Climate. Cultural Foundation Publications, Abu Dhabi, p 240 Mohamed M, Almualla A (2010a) Water demand forecasting in Umm Al-Quwain (UAE) using the IWR-MAIN specify forecasting model. Water Resour Manag 24(14):4093–4120 Mohamed M, Almualla A (2010b) Water demand forecasting in Umm Al-Quwain using the constant rate model. Desalination 259:161–186 Mohamed MM, Elmahdy SI (2015) Natural and anthropogenic factors affecting groundwater quality in the eastern region of the United Arab Emirates. Arab J Geosci 8:7409–7423 Mohamed M, Hatfield K (2005) Modeling microbial-mediated reduction using the quasi-steady-­ state approximation. Chemosphere 59:1207–1217 Mohamed M, Hatfield K (2011) Dimensionless Monod parameters to summarize the influence of microbial inhibition on the attenuation of groundwater contaminants. Biodegradation 22:877–896 Mohamed M, Hatfield K, Hassan AE, Klammler H (2009) Stochastic evaluation of subsurface contaminant discharges under physical, chemical, and biological heterogeneities. Adv Water Resour 33(7):801–2010 Mohamed M, Hatfield K, Perminova IV (2007) Evaluation of the biological parameters in the subsurface using moment analysis: theory and numerical testing. Adv Water Resour 30(9):2034–2050 Mueller DK, Helsel DR (1996) Nutrients in the Nation’s waters-too much of a good thing? U.S. Geological Survey Circular 1136, p 24 Murad AA, Gerish MH, Mahgoub FM, Hussein S (2011) Physiochemical processes affecting the geochemistry of carbonate aquifer of Southeastern Al-Ain Area, United Arab Emirates. Water Air Soil Pollut 214:653–665 Murad A, Mahgoub F, Hussein S (2012) Hydrogeochemical variations of groundwater of the northern Jabal Hafit in eastern part of Abu Dhabi Emirate. United Arab Emirates (UAE). Int J Geosci 3:410–429 Ni Y, Dai J, Zhou Q, Luo X, Hu A, Yang C (2009) Geochemical characteristics of abiogenic gas and its percentage in Xujiaweizi fault depression, Songliao Basin, NE China. Pet Explor Dev 36:35–45

References

589

Oram B (2007) Water Research Centre E. Coli in Water: retrieved from Water Research Centre website. http://www.water-research.net Raskin I, Nanda-Kumar PBA, Dushenkov S, Salt DE (1994) Bioconcentration of heavy metals by plants. Curr Opin Biotechnol 5:285–290 Plazinska A (2000) Microbiological quality of drinking water in four communities in the Anangu Pitjantjatjara Lands, SA. Bureau of Rural Sciences, Canberra Rainwater FA, Thatcher LL (1960) Methods for collection and analysis of water samples: U. S. geological survey water supply paper no. 1454, Washington, pp 1–301 Rizk ZS (1998) Falajs of United Arab Emirates: geological settings and hydrogeological characteristics. Arab J Sci Eng 23:3–25 Rizk ZS (2009) Factors controlling distribution of trace elements in groundwater of the United Arab Emirates. Int J Sci Res 19:13–38 Rizk ZS (2014) Determining the sources of nitrate pollution of the Liwa Quaternary aquifer in the United Arab Emirates. In: WSTA 11th Gulf water conference, water in GCC. Towards efficient management, 20–22 October 2014, Muscat, Sultanate of Oman, pp 120–136 Rizk ZS (2015) Why Wadi Ab Bih limestone is the most sustainable aquifer in the United Arab Emirates? Int J Sustain Water Environ Syst 7(1):21–28 Rizk ZS, Alsharhan AS (2003) Water resources in the United Arab Emirates. In: Alsharhan AS, Wood WW (eds) Water management perspectives: evaluation, management and policy. Elsevier Science, Amsterdam, pp 245–264 Rizk ZS, Alsharhan AS, Shindo SS (1997) Evaluation of groundwater resources of United Arab Emirates. In: Proceedings of the third Gulf water conference, Muscat, Sultanate of Oman, pp 95–122 Rizk ZS, El-Etr HA (1997) Hydrogeology and hydrogeochemistry of some springs in the United Arab Emirates. Arab J Sci Eng 22:95–111 Rizk ZS, Garamoon HK, Abu Sara HS (2017) Hydrogeochemistry and microbiology of Wadi Al Bih limestone aquifer in Northern United Arab Emirates. J Res Environ Earth Sci 3(3):1–14 Rizk ZS, Garamoon HK, El-Etr AA (1998) Hydraulic properties of dune and interdune areas around Al-Ain, United Arab Emirates. In: Alsharhan, Glennie, Whittle, Kendall (eds) Proceedings of the international conference on quaternary deserts and climatic change. Balkema, Rotterdam, pp 455–467 Rizk ZS, Garamoon HK (2006) The influence of major lineaments on groundwater resources in the eastern region of the United Arab Emirates. Univ Sharjah J Pure Appl Sci,. ISSN 1811 1645 3(3):83–111 Rus A, Baxter I, Muthukumar B, Gustin J, Lahner B, Yakubova E (2006) Natural variants of AtHKT1 enhance Na+ accumulation in two wild populations of Arabidopsis. PLoS Genet 2:210 Sherif MM (2006) Geoelectrical and hydrogeochemical studies for delineating seawater intrusion in the outlet of Wadi Ham, UAE. Environ Geol 49(4):536–551 Sherif M, Mohamed M, Kacimov A, Shetty A (2011) Assessment of groundwater quality in the northeastern coastal area of UAE as precursor for desalination. Desalination 273(2):436–446 Sherif MM, Sefelnasr A, Javadi A (2012) Incorporating the concept of equivalent freshwater head in successive horizontal simulations of seawater intrusion in the Nile Delta Aquifer, Egypt. J Hydrol 464–465:186–198 Sherif M, Sefelnasr A, Ebraheem A, Javadi A (2014) Quantitative and qualitative assessment of seawater intrusion in Wadi Ham under different pumping scenarios. J Hydrol Eng 19:855–866 Simpson JM, Santo Domingo JW, Reasoner DJ (2002) Microbial source tracking: state of the science. Environ Sci Technol 36:5279–5288 Skoog DA, West DM, Holler FJ, Crouch SR (2004) Fundamental analytical chemistry, 8th edn. Thomson Brooks/Cole, Belmont, p 870 Spalding RF, Exner ME (1991) Nitrate contamination in the contiguos United States. In: Bogardi I, Kuselka RD (eds) Nitrate contamination. Springer, Berlin, pp 13–48 Spalding RF, Kitchen LA (1988) Nitrate in the intermediate vadose zone beneath irrigated cropland. Groundwater Monit Rev 8(2):89–95

590

18  Groundwater: Quality Degradation and Water Pollution

Spoolman E, Scotte M, Tyeler G (2009) Living in the environment, 16th edn. Nelson Education, ttd, Pacific Grove, p 533 Szatmari P, da Fonseca TCO, Miekeley NF (2011) Mantle-like trace element composition of petroleum – contributions from serpentinizing peridotites. In: Closson D (ed) Tectonics, vol 3. InTech, Rijeka, pp 332–358 Tortora GJ, Funke BR, Case CL (2010) Microbiology, 10th edn. Pearson Education, Inc., San Francisco, p 431 Tourenq C, Shuriqi MK, Sawaf M, Smart E, Brook M, Selwan R, Ziolkowski M (2009) Characterisation of the Wadi Wurayah catchment basin, the first mountain protected area in the United Arab Emirates. Int J Ecol Environ Sci 35:289–311 Uqba KA (1991) The water resources of the united Arab emirates: a comprehensive emperical appraisal of their status and management: PhD thesis, Durham University Vela NP, Olson LK, Caruso JA (1993) Elemental speciation with plasma mass spectrometry. Anal Chem 65(13):585–597 Weiss J (1986) In: Johnson EL (ed) Handbook of ion chromatography. Dionex Corp, Sunnyvale WHO (World Health Organization) (1984) WHO guidelines for drinking water quality: volume 1, recommendations. Geneva, Switzerland, p 130 Wolf RE, Grosser ZA (1997) Overview and comparison of ICP-MS methods for environmental analyses. At Spectrosc 18(5):145–151 Wood WW (1976) Guidelines for collection and field analysis of ground-water samples for selected unstable constituents: techniques of water resources investigations, U. S. Geological Survey, Book 1, Chapter D2, U. S. Government Printing Office, p 24 Wood WW, Rizk ZS, Alsharhan AS (2003) Timing of recharge, and the origin, evolution and distribution of solutes in a hyper arid aquifer system, developments in water science (50). In: Alsharhan AS, Wood WW (eds) Water resources perspectives: evaluation, management and policy. Elsevier, Amsterdam, pp 245–264

Part VII

Integrated Water Resources Management

The transformation of the concept of integrated water resources management in the UAE into concrete actions on the ground can be achieved through the development and implementation of policies and good practices for water management, with particular emphasis on water-demand management, reduction of groundwaterexploitation rates, sustainable management of aquifer systems, development of nonconventional water resource, such as desalinated water and treated wastewater, expansion in brackish water use, coordination and institutional arrangements for water-resources management and maximizing the role of the private sector in waterresources planning and management. Water conservation in the UAE can be achieved by reducing freshwater use through community practices and technological solutions, reduction of water use and decrease of water loss, as well as public awareness of water issues and water-­ related problems on the individual and society levels. In the UAE, old and modern water-harvesting mechanisms and techniques have been used, such as cloud seeding and artificial precipitation and rainwater harvesting with the use of barriers, habisas and ponds. Also being used are groundwater-­ recharge dams and their role in aquifers’ recharge and the improvement of groundwater quality, aflaj systems, artificial recharge and aquifer storage and recovery projects in some emirates such as Abu Dhabi and Sharjah. Application of advanced agricultural techniques is important because agricultural activities are the main consumer of water on Earth. Recent efforts focus on the wider use of modern agricultural methods to reduce the burden on conventional water resources, especially groundwater. The use of groundwater for irrigation is the main cause of aquifers’ depletion, but now the modern irrigation techniques, such as drip irrigation, sprinklers and bubbles, and protected agriculture in greenhouses are heavily used. Biosaline agriculture could contribute effectively to integrated water resources management because it enables the use of marginalized resources, i.e., salt water and sabkha areas.

Chapter 19

Water Conservation and Integrated Management

Abstract  To conserve flood water, the Emiratis have practiced surface-water harvesting for hundreds of years for agricultural and domestic purposes. They have built barriers, open or covered “berkas” (ponds) and “habisas”. Starting in the 1980s, the government has built more than 130 groundwater-recharge dams capable of storing 120 m3 and is planning to build 68 additional dams. The UAE political leadership has realized the water-shortage problem and each emirate has at least a law or an Amiri Decree, regulating water-well drilling and groundwater extraction and protection. However, the detailed implementation procedures have to be formulated and put in action. The Abu Dhabi Food Control Agency (ADFCA) has provided a number of initiatives for reducing water wastage in agriculture, including reduction of water consumption in farms, use of treated wastewater for irrigation, promoting sound agricultural practices, phasing out Rhodes grass cultivation, improving irrigation networks, application of smart irrigation systems, improvement of soils and expansion in greenhouse agriculture. The chapter also discusses demand-and-supply management of desalinated water, and reuse of treated wastewater, in additional to technological solutions and social practices. The technological solutions include implementation of aquifers’ safe yield, controlling water wastage, minimizing water losses and water tariffs. The social responsibility involves improving planning and raising awareness.

19.1  Introduction According to the OECD (2001): “water conservation refers to the preservation, control and development of water resources, both surface and groundwater and prevention of pollution”. But, since water desalination and reclaimed water have become an integral part of water resources in the UAE, the definition must be extended to include both water resources. The MOEW (2010) pointed out the great importance of water management and conservation in various sectors of water use and production. © Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_19

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Al-Zubari (1997) stressed that no higher quality water should be used for a purpose that can tolerate a lower quality. The idea of managing water demand is new and the main efforts expended over the past few decades were towards increasing water supplies to meet the ever-increasing demand, with almost no concern for the environmental impact and financial expenses. As a consequence, the limited available natural water resources are overexploited, while individual water consumption in the UAE is one of the highest in the world. This situation will get worse as the population continues to grow. In fact, the population doubled between 2009 and 2015, reaching almost ten million at the present. Lack of water conservation measures is not only degrading the environment and increasing gas emissions but also is very expensive, and the UAE has to provide heavy subsidies to secure enough and an adequate water supply for various uses. The UAE needs to promote water conservation and management. In this regards, the MOEW (2010) stated: “The UAE needs effective plans for water management and conservation, otherwise groundwater resources will be depleted soon and the country would have to totally depend on desalinated water and reuse of treated wastewater. In addition to environment protection, water conservation is of a financial and economic value. The costs of water use the UAE is about AED 18.2 billion (US$ 4.96 billion) a year, of which consumers pay about 28% (US$ 3.57 billion) and government subsidize the remaining AED 13.1 billion (US$ 3.57 billion) per year”. In the UAE, individual water use is double the international standard. For this reason, it is important to set policies for managing water demand that suit the consumers, society and culture, in addition to the economy and the natural environment. In this case, it is always beneficial to study actions taken in countries with similar social and cultural structure. Research studies, including actual surveys, are needed to develop water-conservation policies conformable with the economic, social and environmental norms of the country. In 2010, about 4600 Mm3 of water was used in the UAE. Consumers paid only 22%, while the 2900 Mm3 or 63% represented by groundwater and treated wastewater supplies were provided free of charge. The MOEW (2010) declared: “The desalinated water is highly subsidized, particularly in Abu Dhabi Emirate, where the desalinated water tariff is AED 2.2 (US$ 0.6) per m3 in Abu Dhabi City, that is served by Abu Dhabi Water and Electricity Authority (ADWEA), to as much as AED 8.8 per m3 in the northern emirates, which are served by Federal Electricity and Water Authority (FEWA). Commercial and industrial sectors consume 700 Mm3 (40%) of desalinated water and pay a similar tariff. Therefore, the cost of producing desalinated water is much higher than the tariffs charged and consumers pay less than the full cost, the implicit subsidy is about AED 6 (US$ 1.64) per m3 of desalinated water and AED 4.8 (US$ 1.31) per m3 of treated wastewater. The cost of groundwater is very difficult to estimate because almost all the production is private and until recently most of the initial capital investment in drilling agricultural wells and installing pumping equipment was heavily subsidized by Emirates’ and Federal governments. The groundwater is usually provided free of charge but users pay the production cost. The MOEW (2010) estimates of production costs range from AED 0.85 (US$ 0.23) to AED 1.60 (US$ 0.44) per m3”.

19.2 Flood-Water Conservation

595

The rate of groundwater pumping far exceeds the recharge rate from rainfall, leading to fast depletion of major aquifer systems. When farmers run out of groundwater, they have no other option than usage of desalinated water. Installation of on-farm desalination plants has become a common practice in the country, where a small reverse-osmosis (RO) plant is installed and connected to wells supplying salt water as the plant feed water. Alternatively, desalinated water can be provided by one of the commercial suppliers. The cost of groundwater is difficult to assess. But, when the preferred alternative of groundwater is desalinated water, in some areas such as Al Ain, then the cost of groundwater and desalinated water becomes equal.

19.2  Flood-Water Conservation The government has heavily invested to build retention and detention dams in the northern and eastern parts of the country to harvest seasonal floods (Fig. 3.4). Rainfall in northern emirates is usually double the country’s mean annual average, and rare sporadic rainstorms can cause flash floods that earlier were dissipated through evaporation, lost into the sea or in the vast desert plains of the western region. In order to capture this valuable freshwater resource, the UAE government started building groundwater-recharge dams in early 1980s. More than 130 dams were built mostly the northern and eastern parts of the country. These dams are capable of storing 120 m3. The MOEW (2010) mentioned that there 68 dams in the planning stage. The main function of dams is to catch a large part of the floodwater, directing this water downward to recharge aquifers. The surface water detained in the dam reservoir has been directly used in agriculture. According to the MOEW (2010), until 2007, the government has invested AED 857 (US$234) million in building major dams, which has captured 105 Mm3. High evaporation rates lead to major losses of water stored in dammed reservoirs and increased water costs. The potential contribution of recharge dams to the agricultural demand varies from one emirate to the other, reaching a maximum of 7% in Fujairah (Fig. 19.1). Except Fujairah, the contributions of dams to agricultural water needs are very small even if it were all used. The desirability of building dams has always differed between upstream and downstream residents. The upstream side gets the benefit of the water stored in the reservoir and the rise of groundwater levels, while the downstream loses the benefit of floodwater and may also suffer from salt-water intrusion in coastal areas. However, once some floodwater recharges the aquifer, farmers in upstream and downstream zones can benefit by pumping of better quality water. Groundwater-­ recharge dams are continuously monitored by the Ministry of Climate Change and Environment, and their reservoirs have to clear and the flood silt removed in order to maintain groundwater recharge.

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10%

7%

5% 3% 2%

2% 0%

0% Fujairah

RAK

Dubai

Ajman

Abu Dhabi

0% Sharjah

Fig. 19.1  The percentage contribution of water stored in dam reservoirs to agricultural water demand in the UAE. (After MOEW 2010)

19.3  Groundwater Conservation Rizk (2014) addressed a meeting of experts to discuss local policies on groundwater conservation in the UAE. The meeting was: “attended by representatives of the Abu Dhabi Environment Agency (EAD), Dibba Fujairah Municipality (DFM), Ajman Municipality and Planning Department (AMPD) and Umm Al Quwain Municipality, and discussed the efforts of participating emirates in management and conservation of their groundwater resources”. Discussion among the participants and lecturers revealed that the UAE political leadership has realized the water-shortage problem since the constitution of the UAE Federation on the 2 December 1971. The Emirate of Abu Dhabi issued Law Number (6) for (2006) on regulation of water-well drilling and groundwater extraction and protection. Dubai Emirate issued Law Number (15) for (2008) on groundwater protection in the Emirate; Sharjah also issued the Law Number (1) for (2013) on the preservation of water resources in Sharjah; and the Emirate of Ajman issued the Emiri Decree number (4) for (2009), regarding organization of the drilling of water wells and groundwater exploitation. Ras Al Khaimah Emirate issued Law Number (5) for (2006), organizing the drilling of groundwater wells. The Emirate of Fujairah issued Law Number (2) for (2011) on the regulation of water-well drilling and groundwater extraction and protection. Finally, the Emirate of Umm Al Quwain also issued Law Number (2) (2008) on groundwater protection and regulation of water-well drilling in the Emirate. The meeting discussed the efforts of participating emirates in conservation of their groundwater resources. One of the main recommendations of this meeting was

19.3 Groundwater Conservation

597

the importance of establishing detailed procedures for implementation of the issued laws and decrees in order to slow down, or if possible reverse, the depletion of aquifers throughout the country. According to the ADFCA (2015), agriculture is the largest consumer of groundwater in the UAE. Therefore, water-conservation efforts were directed to this particular sector, where farmers are UAE nationals who own the farms and receive irrigation water free of charge. MOEW (2010) stated: “The Public parks consume 6% of the annual water budget followed by industrial (9%), domestic (25%) and agricultural (60%) sectors”. The average per capita fresh water consumption in UAE is among the highest in the world, reaching 500 liters per day in Abu Dhabi. The licensing and monitoring water wells were difficult because farmers believe that the water beneath their land is their property and that the government is attempting to make them pay for water they already own. This is not a particular case of UAE, but this is the same everywhere in the world, whether the country is developing or developed. The results of a survey conducted by the International Center for Biosaline Agriculture (ICBA 2012) indicate that the government subsidies disrupt agricultural production. Farmers are making exceptionally good returns form fodder crops, particularly Rhodes Grass, despite its high water consumption (Fig. 19.2). The government subsidies of irrigation network and water supply to farms all over the country has doubled the consumption of on-farm water (Fig. 19.3). MOEW (2010) called for: “Stop growing Rhodes Grass is a water conservation practice and could lower water consumption in the country by 460 Mm3 per year. If the full price is charged, only fruits justify the use of groundwater for irrigation in the UAE, and if only the cost of water supply is considered, excluding subsidies, vegetables also many become profitable”. $30,000 without subsidy

with subsidy

$25,000 $20,000 $15,000 $10,000 $55,000 $0

Field crops

Green houses

Datas

Rhodes grass

Fig. 19.2  The effect of agricultural subsidies on farm potentiality and groundwater use. (After MOEW 2010)

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Farm water use (Million cubic meter per ha) 250000 without subsidy

with subsidy

Green houses

Datas

20000

15000

10000

5000

0

Field crops

Rhodes grass

Total

Fig. 19.3  Farm water use in million m3 per hectare. (After MOEW 2010)

The ADFCA (2015) provided a number of initiatives for the implementation including: reduction of water consumption on farms, use of treated wastewater for irrigation, promoting good agricultural practices, phasing out Rhodes grass cultivation, importation of fodder, improving irrigation networks, application of smart irrigation systems, improvement of soils and expansion in greenhouse agriculture. The following is a brief discussion on these initiatives. The ADFCA studied water consumption levels in 200 farms throughout Abu Dhabi Emirate. Water meters were installed after classifying the farms into vegetables, palms and fodder farms. The obtained results were used for development of future plans focusing on the wise use of water for irrigation. Treated wastewater was used for irrigation of all type of crops in 143 farms, and the crops produced by these farms is suitable for human use. Treated wastewater, after a fourth sterilization phase, was also used for irrigation of crops on 216 farms. The results show that water, soil and plants were found free of pathogenic bacteria. Results also showed high concentrations of some nutrients and beneficial elements for the plants in the applied treated wastewater, which are not found in groundwater or desalinated water used for irrigation. Expansion in the use of treated wastewater in agriculture can promote sustainability of water resources and avoid depletion of major aquifer systems. ADFCA has introduced a project to promote good agricultural practices in the country. The project ensures safety of local agricultural products and workers in the agricultural field. The project was applied in 110 farms in Abu Dhabi, which were awarded certificates for successful completion of the program. The UAE decision to ban cultivation of Rhodes grass reduced groundwater consumption by 42% in 2009. Alternative fodder crops introduced by the ADFCA

19.4 Desalinated Water

599

required much less water, did not increase soil salinity and were harvested eight to ten times per year compared to five to six harvests for Rhodes. The mean annual average rainfall was 119  mm during the period 1974–2003, dropped to 83 mm during the period 2003–2015 because of the climate change. The average annual recharge is 120 Mm3, while the groundwater consumption for irrigation, which is around 1.5 Bm3, is about 50% of the total consumption in the Abu Dhabi Emirate. The ADFCA adopted new technologies for irrigation of palm trees, which consume 34% of irrigation water. A total of 2333 out of 8000 farms have been provided with modern irrigation networks that are expected to reduce water irrigation consumption by 50% in some farms (ADFCA 2015). The application of smart irrigation systems helps in irrigation scheduling, improve the irrigation efficiency, identify the amount of irrigation water needed to maintain the soil moisture reservoir and determine the seasonal irrigation water requirements of various crop types. These systems include wireless sensors operating via satellites and connected to an automatic operating system, which is programmed in a way that takes into account the types of crops and the exact water requirements for various seasons. Studies are being carried out also on various materials of soil amendments, such as high-quality thermally treated organic fertilizers, addition of biomaterials to organic fertilizers, the use of organic water retainers in the soil and the use of slow-­ release fertilizers and controlled-release fertilizers. The ADFCA, along with the Environment Agency of Abu Dhabi (EAD), established a greenhouse agriculture center in Al Ain for testing the latest farming techniques and agriculture in protected soil substitutes. This system is considered to be one of the most efficient techniques for water use in agriculture, because it increases crop productivity and reuses 95% of irrigation water.

19.4  Desalinated Water MOEW (2015) indicated that: “The UAE has adopted water desalination since early 1970’s to bridge the gap between limited natural water resources and the growing demand on water by different sectors. The production of desalinated water increased from 7.0 Mm3 in 1973 to 1.75 Bm3 in 2013. Now, the country has 266 desalination plants in operation (ICBA 2012), mostly located in coastal areas, with a few plants in desert areas”.

19.4.1  Demand Management There is enough information on the efficiency of desalinated water used for domestic purposes, while the MOEW (2010) confirmed the lack of enough data on: “The volumes of desalinated water designated for industrial and commercial activities.

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Table 19.1  Increase in domestic water consumption during the period 2004–2008 in the United Arab Emirates Emirate Abu Dhabi Dubai Sharjah Ajman Umm Al Quwain Ras Al Khaimah Fujairah

Year 2004 405 303 124 227 194 234 104

2006 505 354 146 247 220 256 112

2008 526 377 158 295 225 266 136

MOEW (2010)

Fig. 19.4  Evolution of per capita water share in the UAE during the period 2004–2008. (After MOEW 2010)

Parallel to the growth of domestic demand for water, the per capita residential water use has grown steadily over the last four years, in line with the national policy that all domestic demand for water should be met (Table 19.1)”. In the UAE, individual water use is very high in comparison with other countries (Table 16.3). Figure 19.4 shows that the average per capita water share in the UAE has increased from 227 lpcpd in 2004 to 283 lpcpd in 2008, while the maximum consumption was measured in Abu Dhabi Emirate, ranging between 405 lpcpd in 2004 and 526 lpcpd in 2008. The average per capita water consumption of 16 industrial countries including the UK Australia and USA is 197 lpcpd, while the UAE average is 364 lpcpd

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(MOEW 2010). Therefore, reduction of the current domestic water consumption by 50% (182 lpcpd) is achievable and will cause no harm to human health. In addition, the use of treated wastewater for toilet flushing can reduce domestic freshwater use by an additional 50%. But, this might require a change in public attitude towards wastewater reuse and installation of dual water-supply systems in new buildings. The consumption of desalinated water can be reduced by introducing effective management and pricing mechanisms. International approaches make customers pay for improvement of physical facilities, such as improvement of distribution networks and reduction of leakages and unaccounted for water.

19.4.2  Supply Management The unaccounted-for water (UfW) includes physical losses related to distribution systems, such as defective water meters and leaking valves and pipes, in addition to administrative losses such as illegal connections and non-billed customers. In 2007, the physical losses estimated by Abu Dhabi Distribution Company (ADDC) accounted for 16%, while administrative losses accounted for 19%. Then, the overall UfW was 35% of the supply. According to the MOEW (2010), taking into consideration the construction material and the age of the water-distribution system, these percentages are excellent by international standards. However, in comparison with the percentage of the UfW in Singapore, which was 5.1% in 2004, there are several areas suitable for improvement in the UAE. Without efficient allocation of desalinated water, water-supply management may not succeed. Figure  19.5 shows that the water needs of the Al Ain area between

Water imports (million cubic meters) 300 250

241

From Fujairah

254

200 150

122

135

100 50

101 40

From Abu Dhabi

0 1988

2000

2002

2004

2006

2008

Fig. 19.5  Uncontrolled water imports may lead to increasing water wastage. (After MOEW 2010)

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1988 and 2004 were met by desalinated water in Abu Dhabi. In 2004, desalinated water from Fujairah represented an additional source water for the Al Ain area. As a result, per capita water consumption in Al Ain increased sharply. Much of the additional desalinated water supplied to the Al Ain area from Abu Dhabi and Fujairah desalination plants is being used for irrigation. On the contrary, the treated wastewater was disposed of into a nearly basin and a wadi spread across the city. This water has caused local water logging and groundwater pollutions problems (Fig. 16.3). Instead, treated wastewater might be used in some applications to ease reliance on expensive desalinated water and the depletion of fresh groundwater resources.

19.5  Treated Wastewater In 2015, the UAE produced 711 Mm3 of treated wastewater, and 511 Mm3 were used, while the remaining 200 Mm3 were disposed of into the sea or wasted in desert areas (MOEW 2015). However, no serious research studies have been conducted on the adverse effect of the discharge of treated wastewater on the marine environment and groundwater resources. Al-Hogaraty et al. (2008) studied the impacts of human activities and hydrogeologic setting of the Quaternary sand aquifer in northern UAE. Results showed that the aquifer is an unconfined, water-table aquifer, receiving a large pollutant flux of 4800 m3/day from a sewage disposal site on the land surface. Field investigations and results of chemical analyses of groundwater samples collected from the aquifer revealed positive anomalies in major ions, groundwater salinity, total hardness, heavy elements and dissolved oxygen. In Al Ain, the waterlogging problem caused by surface disposal of sewage and agricultural drainage water was investigated by Murad et al. (2014). The complex nature of lithological variation and geologic structure on the western side of Jabal Hafit mountain, in addition to intensive agricultural and residential developments, have led to a water-logging problem and water-table rise in Al Shuiaba District of Al Ain City. Differential flooding of basements in several houses along the District showed that in the same area houses just 50–100-m apart may, or may not, be affected by flooding related to sudden and local rise of groundwater table due to the water-logging problem. In an effort to augment the use available water resources, the UAE has recently expanded the use of treated wastewater for forest plantation, landscaping and irrigation of green spaces. But, during the summer months when the demand for treated wastewater exceed production, more expensive alternative water sources are used, such as desalinated water and fresh groundwater. Unfortunately, this practice is still ongoing in some areas. The water used for landscaping in Abu Dhabi in 2008 reached 197  Mm3; of which about 91  Mm3 (46%) was desalinated water, 67  Mm3 (34%) was treated wastewater and 39 Mm3 (20%) was fresh groundwater, indicating that almost two-­

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thirds of the water used are desalinated water and fresh groundwater. This costly, unsustainable water usage has to change towards more reliance on treated wastewater by increasing production of existing wastewater-treatment plants and establishing the infrastructure for wastewater storage. In this regard, Abu Dhabi Municipality has started landscaping main avenues with desert plants, sustaining ambient weather conditions and using less water. In fact, there is an urgent need to expand usage of treated wastewater to ease pressure on desalinated water and depletion of fresh aquifer systems. The MOEW (2010) in the UAE has developed a new policy for treated wastewater reuse aiming to: use of water-saving desert plants in landscaping, establish large and integrated systems for municipal irrigation and put tariffs on desalination water to prevent its usage as a cheaper alternative to other water sources.

19.6  Technological Solutions and Social Practices Technological solutions aim at water conservation for sustainable development and preserve the right of future generations to their share of water. This can be achieved by implementing the philosophy of safe yield of aquifer systems, which means utilizing groundwater at rates that do not exceed the amounts of their natural recharge. Water conservation leads to reduction of energy consumption needed for water pumping, treatment and delivery to consumers. This energy reduction is no less than 15% of total energy consumption in industrial countries. Technological solutions include the use of modern sanitation tools, use of modern water taps, reuse of treated wastewater, water conservation, avoidance of traditional irrigation methods and use of modern irrigation methods, such as the central pivot, sprinkler, bubble and drip. These methods are expensive but are more economical and save irrigation water. Efficient water use aims at reduction of water wastage, where the least amount of water is used to meet the demand. The primary purpose of the efficient use of water is not to reduce the use but to minimize water wasting (Nairn 2003). Users can contribute to increasing the efficient use of water by selecting the most efficient product and stopping leakage and wastage in water use for all purposes. Social practices include awareness campaigns, water pricing, reduced prices of water-saving tools and irrigation equipment and use of plants that withstand the desert climate and salt-tolerant plants used for landscaping. Expansion in the installation of water meters is needed because more than half of the water is not metered, even in industrial countries such as Canada (33%) and United Kingdom (70%). The US Environmental Protection Agency (EPA) has estimated that installation of water meters can reduce water consumption by 20 to 40% (EPA 2012). In addition to its role in raising awareness of individuals regarding water issues, the EPA identifies sources of water leakage and those who are responsible for water wastage. Most scholars focus on raising the awareness of agricultural workers because irrigation water is responsible for 70% of global freshwater use. Awareness must

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Table 19.2  Annual water consumption in the United Arab Emirates, based on data from the Ministry of Energy Year 1997 1998 1999 2000 2001 2002

FEWAa 52.0 56.0 55.6 60.9 65.4 68.7

ADEWAb 182.0 208.3 221.0 241.8 277.0 337.0

DEWAc 108.9 123.3 136.2 146.1 157.1 168.8

SEWAd 27.9 30.7 33.7 37.0 41.2 44.9

Total (Mmc) 370.8 418.3 446.5 485.8 490.7 619.4

FEWA = Federal Electricity and Water Authority ADEWA = Abu Dhabi Electricity and Water Authority c DEWA = Dubai Electricity and Water Authority d SEWA = Sharjah Electricity and Water Authority a

b

focus on cultivation of water-saving crops, in addition to the application of modern irrigation methods. According to the Economic and Social Commission for Western Asia (ESCWA 2005), the total water consumption by the various sectors in the UAE in 2005 was about 2925  Mm3, distributed as follows: 1914  Mm3 for the agricultural sector; 300 Mm3 for the industrial sector; and 711 Mm3 for the domestic sector. Given that the annual renewable-water resources in the UAE is estimated at 310  Mm3, the water deficit during 2005 amounted to 2615 Mm3. The annual water consumption in the UAE has increased from 371 Mm3 in 1997 to 619 Mm3 in 2002 (Table 19.1). Among the many reasons for the resulting water deficit in the UAE is that the population has been increasing by a rate of 3.7% per year, while the global average varies between 0.7% and 1.7%. The continuous increase in population with increasing water demand, illustrated in Table  19.2), reflected an increase in population from 2.7 million in 1997 to 3.5 million in 2002, which required additional water resources year after year. On the other hand, Table 19.2 shows that the increase in per capita water consumption from 478.5 liters per day (L/day) in 1997 increased to 596.1  L/day in 2002. The urban development in the UAE increased demand for conventional and nonconventional water resources alike. In spite of the scarcity of rainfall and dry climate, the quantities of water wastage reached a record rate. The UAE must adopt strategies for water conservation and harvesting, in addition to expanding advanced farming and applying new irrigation technologies.

19.6.1  Controlling Water Wastage The UAE consumes groundwater ten times more than the natural recharge capacity, which leads the water deficit reaching 2615  Mm3 in 2005. The groundwater exploitation for irrigation reaches one-billion cm3 per year, resulting in serious depletion of aquifers. In 2005, the total volume of water available in the UAE was 1170  Mm3, the population was 3.25 million (ESCWA 2005) and the per capita

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Table 19.3  Average daily water consumption per capita in the UAE in liters per day, based on data from the Ministry of Energy Year 1997 1998 1999 2000 2001 2002

Water consumption (Million liter/day) 1284.4 1428.8 1565.6 1675.8 1816.4 2078.6

Population (Million) 2.684 2.759 2.938 3.103 3.277 3.487

Per-capita water consumption (Liter/day) 478.5 517.9 532.9 540.1 554.3 596.1

share was 360 m3. With a total water use of 2925 Mm3 during the same year, the per capita water consumption measures 1323 m3, which represents one the highest in the world (Table 19.3). There are no accurate estimates of water losses from water-distribution networks in the UAE compared with the GCC countries, where the losses vary between 40 and 60%, in addition to the unwise water use among cities residence. Examples are: irrigation of private farms and green areas and car wash using large amounts of drinking water. Assuming the water loss from distribution networks in the UAE is the minimum in GCC countries (40%), it will still be too high compared with Japan, where the loss of water distribution network is 10%. Despite limited available water resources in the UAE, there is no comprehensive plan for the management and development of water resources. Water policies are fragmented and incomplete. The development of the agricultural sector and expansion of the green area were at the expense of the aquifers’ storage. The groundwater pumping violated the safe yield of almost all aquifer in the UAE, leading to aquifers’ depletion, increase of groundwater salinity, decline of hydraulic heads and dryness of thousands of wells. The lack of legal actions against unlawful drilling activities and the absence of pricing of agricultural water has led to excessive groundwater pumping rates. So far, groundwater satisfied agricultural water needs, but this contribution is subject to falling short because of the large difference between large groundwater discharge and limited natural recharge. According to the most optimistic estimates, ESCWA (2005) calculated the groundwater storage in UAE at about 20 billion m3. This storage is expected to be run out in less than 23 years. At present, the hydraulic heads are declining (Figs. 16.1 and 16.2) and groundwater quality is deteriorating (Figs. 9.6 and 13.14), due to the salt-water intrusion (Fig. 13.25). Shallow aquifers are suffering from pollution with agricultural drainage water or partially treated sewage water, in addition to other surface contamination sources.

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19.6.2  Minimizing Water Loss In the UAE, the waste of irrigation water must be stopped through greater use of modern irrigation methods. For saving large amounts of water, conservation efforts should focus on agricultural activities, which constitutes the greatest water consumption globally. On the other hand, water leakage which may exceed 40% in distribution networks has to be reduced. The loss of one drop of water per minute leads to the loss of 11 m3 of water worldwide. Damaged connection lines should be better maintained and replaced to enhance delivery and distribution methods that will reduce water loss in networks. The UAE should pass legislation prohibiting the use of freshwater in car washes and gas stations, and many other uses could be replaced by lower quality water. Coordination among all parties dealing with water and the distribution of roles between them saves time and effort that has a positive impact on all sectors. On the consumer side, efforts should focus on minimizing leakage in distribution systems, expansion in reuse of treated wastewater for some purposes such as refrigeration and car washing, use of amended septic tanks consuming less water, use of automatically closing taps in public places and government facilities (Pearson 1993; Whitcomb 1991) and water pricing.

19.6.3  Sequential Water Use Sequential water use means water treatment and use for the purpose, followed by water use for another purpose that needs lower quality water. For example, household uses require the highest quality water. The sequence of water use can be arranged as follows: water is used first for household purposes, followed by industry and agricultural activities at the end. The wastewater can be treated and used in agriculture, which increases agricultural production and reduces the need for chemical fertilizers because it contains a relatively high concentration of nitrogen and phosphorus. Treated wastewater can be used in irrigation of playgrounds, citrus and olive trees, public parks and some crops.

19.6.4  Water Tariffs MOEW (2015) defined the purposes of water pricing to reduce water demand, decreased per capita water consumption and increase revenue f domestic water use. Under the present water consumption, the demand exceeds the desalination capacity. However, the MOEW (2010) foresees: “with a decrease in per capita consumption there would be a surplus supply until 2026. Annual water savings would increase from 310 Mm3 in 2015 to more than 760 Mm3 in 2030. The environmental

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benefits of reducing brine discharge by 40,000 Mm3 and the reduction in emissions of greenhouse by about 44 million tons could be achieved; the economic savings would be very much greater”.

19.6.5  Improved Planning MOEW (2010) believes in the establishment of National Water Council to provide leadership and coordinate the efforts required to manage water demand and achieve saving in expenditure on water usage and costs of operating water facilities. The UAE Federal Government is the institution capable of engagement with local governments to strengthen cooperation to harmonize policies and procedures, planning efforts, legislation, standards and regulations. Improvement of planning involves cross-sectoral cooperation and coordination, infrastructure, water sources and sectorial demands, in addition to surveys, research studies and environmental analyses. The main target of improved planning is to maximize benefits and reduce costs. However, a centralized national water-conservation body may face difficulties related to the multiplicity of agencies and institutions dealing with water and the absence of national standards organizing water production and consumption.

19.6.6  Awareness Water conservation is the duty of the government and individuals. The public must be aware and informed of the dimensions and consequences of the water crisis to encourage their participation in water conservation and the reduction of pollution. The citizens and residents need to avoid negative habits in water use and to stop irrational water use. There is a real need for spreading awareness in schools, educational institutions and municipalities to introduce adjustments to home sewage connections, allowing the reuse of treated wastewater in some applications. Farm owners and agricultural workers have to select modern irrigation methods that are optimal to plants and soils, such as drip, sprinkler or bubbles and to choose appropriate plants. Greenhouses can be used in protected agriculture because of their water conservation and reduction of evaporation. Some material can be added to help plants grow and retain water for the longest time possible. It is also possible to cultivate plants that need low amounts of irrigation water and can tolerate high salinity. In 2015, ADFCA, along with concerned groups and agencies, organized seminars and workshops for raising public awareness regarding the wise use of water resources. As the major user of water in the world is agriculture, farmers were the prime target of these activities. In addition, awareness campaigns including organization of exhibitions, field visits and international conferences were conducted in order to promote water-conservation measures and to adopt best practices in water- resources management.

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In homes, modern faucets are designed to reduce water flow and consumption. Washing baths with fabric instead of water could save substantial amounts of water. In addition, opening the faucet in moderation during washing, shaving and teeth brushing can save large amounts of water. Children should be accustomed to use shower stalls instead of bathtub when showering. There is a constant need for periodic maintenance of the water system within the home and repair of any leaks or broken pipes or tools as quickly as possible.

References ADFCA (Abu Dhabi Food Control Authority) (2015) Initiatives to insure sustainability of water resources. Abu Dhabi, UAE, p 7 Al-Hogaraty EA, Rizk ZS, Garamoon HK (2008) Groundwater pollution of the Quaternary aquifer in northern United Arab Emirates. Water Air Soil Pollut 190:323–341 Al Zubari WK (1997) Towards the establishment of a total water cycle management and re-use program in the GCC countries. In: The third Gulf water conference, Muscat, 1997, 1:1–15 EPA (U.S.  Environmental Protection Agency) (2012). Water sense at work  – best management practices for commercial and institutional facilities. https://www3.epa.gov/watersense/docs/ ws-at-work_bmpcommercialandinstitutional_508.pdf ESCWA (2005) Development of frameworks to implement national strategies of integrated water resources management in the ESCWA countries. United Nations, New York, p 94. (in Arabic) ICBA (International Center for Biosaline Agriculture) (2012) Developing federal environmental guidelines and standards to monitor and manage the discharges from desalination plants in the United Arab Emirates, UAE Ministry of Environment and Water, p 119 MOEW (Ministry of Environment and Water) (2006) Wastewater management and reuse. Country profile MOEW (Ministry of Environment and Water) (2010) Water Conservation Strategy: Ministry of Environment and Water, p 212 MOEW (2015) State of Environment Report. Ministry of Environment and Water, United Arab Emirates, p 36 Murad A, Hussein S, Aldahan A (2014) Possible effects of changing groundwater level and chemistry on building foundation of Al Shuiaba residential district Al-Ain city UAE (case study). In: Proceedings of the WSTA 11th Gulf water conference, water in GCC. Towards efficient management, 20–22 October Muscat, Sultanate of Oman, pp 137–143 Narin AEM (2003) Water Management in the Arabian Gulf region and a partial solution to water shortages. In: Alsharhan AS, Wood WW (eds) Water resources perspective. Evaluation, management and policy, Development in water science. Elsevier, Amsterdam, pp 183–189 OECD (Glossary of Statistical Terms) (2001) Glossary of Environment statistics, studies in methods, Series F, 67 Pearson FH (1993) Study documents water savings with ultra-low-flush toilets. Small Flows 7(2):8–9,11 Rizk ZS (2014) Challenges facing groundwater resources in the UAE. Meeting on exchange of expertise in local policies of groundwater conservation. Dibba Fujairah Municipality, 24 March Whitcomb JB (1991) Water reductions from residential audits. Water Resour Bull 27(5):761–767

Chapter 20

Water Harvesting

Abstract The UAE is an arid country with scare rainfall (mean annual rainfall = 119 mm), high temperatures (>45 °C), high evaporation rates (mean annual evaporation = 3322 mm), irregular floods (≈120 Mm3/year) and a lack of permanent surface-water resources, such as rivers or lakes. Because of its limited conventional water resources, the UAE has utilized water desalination, water harvesting and reuse of treated wastewater as nonconventional water sources since early 1970’s. Water harvesting provides additional quantities of good-quality water, which can be used for various purposes. The traditional water harvesting methods have evolved through time from the use of “barriers”, “habisas”, “berkas” and “aflaj” to modern techniques such as cloud seeding and artificial rain, groundwater-recharge dams, artificial recharge, aquifer storage and recovery (ASR) and subsurface dams. The old water harvesting techniques are not yet obsolete and are still in use hand-in-­ hand with the most recent technologies. The amount of water harvested by aflaj varied between 9.0  Mm3 in 1994 and 31.2 Mm3 in 1982. Aflaj water is renewable and is good-to-fair for irrigation. The storage capacity of about 114 existing groundwater-recharge dams is 125 Mm3. The flood water retained by the largest nine dams over the period 1982–2000 was 178  Mm3, and it increased to 211  Mm3 in 2007. The planned construction of 68 additional dams brings the total to 182. Assessment of recharge efficiency revealed the reservoirs of Wadi Tawiyean, Wadi Bih, Wadi Wurrayah and Wadi Ham dams have contributed 22%, 31%, 32% and 47% of aquifer recharge, respectively. The recharge efficiency can be enhanced by exposing the gravel top layer through removal of the thin layer of silt accumulated on the wadi floor. The time interval for cloud seeding and increasing rainfall, through inducing artificial precipitation, is the end of winter season between March and April. The chances for cloud seeding during the summer are better than during winter because the summer clouds have larger sizes of minute particles (400–1000  in cm3) and higher moisture content (0.4–1.2 gm/cm3). Raindrops are larger in summer than winter, and the cloud-moisture content may reach 100% in some areas. The UAE has two pilot aquifer storage recovery (ASR) projects in Abu Dhabi (Liwa and Shuaib) and Sharjah (Nezwa) emirates. Both projects utilize surplus

© Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_20

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desalinated water during the winter for injection into depleted aquifer systems and subsequent retrieval during high demand.

20.1  Introduction In general, the process of water harvesting has several benefits, including: saving water and energy; reduction of soil erosion caused by surface runoff; and provision of an additional source of water for gardening, car washing and irrigation of public parks. Rainwater harvesting is the concentration and storage of rain water, either naturally or through human intervention, after severe rain storms to be able to use it beneficially. Rainwater harvesting is one of the practices of water-demand management and provides additional quantities of water.

20.2  Traditional Water Harvesting Methods The traditional methods of surface-water harvesting include “barriers“, “habisas“and “berkas“, while groundwater harvesting techniques are mainly “aflaj systems“, which account for more than 50% irrigation water in the Sultanate of Oman.

20.2.1  Surface Water Harvesting 20.2.1.1  Rainwater Harvesting Rainwater harvesting provides additional quantities of water and reduces soil erosion associated with runoff. Water harvesting is a key for using rainwater in agricultural activities and goes back 2000 years. Cisterns, varying in size between 200 and 2000 m3 in the northern part of the Western Desert of Egypt, were used to collect untreated rainwater for usage for all purposes. In addition, the physical and chemical properties of rainwater are better than those of groundwater, which may suffer from pollution in many areas. Rainwater-harvesting systems may not need special facilities, but can benefit from the presence of rooftops, parking lots, playgrounds, public parks, small lakes and flood plains. There are no negative environmental impacts for such facilities. Rainwater harvesting provides an additional source of water and eases pressure on conventional water resources. It also represents a reserve for other resources in emergencies and natural disasters and alleviates the burden on sewer systems and streets in large cities, which otherwise can be flooded during heavy rainstorms. Rainwater-harvesting technologies are flexible and can be tailored according to requirements in terms of design, operation and maintenance—at reasonable costs. The Emiratis have practiced water harvesting for centuries for both domestic and agricultural purposes. Rainwater-harvesting techniques included the use of small

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stone barriers across flood courses, and the building of ponds, known locally as “habisas“. An habisa is a low-lying area where rainwater accumulates naturally. In early days, local residents used to build circular or rectangular walls around them to retain and store water. Examples of famous habisas are Al Bithna in Fujairah Emirate and Al Mawrid in Ras Al Khaimah Emirate. In mountainous areas, the people built ponds, known as “berkas“, which are cement or mud holes in the ground, to harvest rainwater flowing from the mountains. The brekas take a square or rectangle shape that are used to store water for several years, and their water was used for drinking and agriculture. There are a number of “berkas” in Wadi Al Bih, Wadi Al Naqab and Wadi Kuda’a in Ras Al Khaimah Emirate. 20.2.1.2  Barriers Barriers of various lengths between 4 and 10 m are designed to collect rainwater in farming areas for irrigation purposes. Small earthen barriers are built at suitable spots on farms near the wadi course. Stone barriers were built on simple slopes to slow down the velocity of flood water and to increase infiltration into the groundwater. This type of barriers is applied in sandy areas such as the central agricultural region in Sharjah Emirate, where alluvial fans are suitable for various agricultural activities. This type of barrier is 2–5 m high and used to irrigate farms and palm plantations. The semi-circular barriers are built facing directly uphill and are built on areas of a farm near the stream valley, where they store rainwater during periods of rainfall. One of these barriers can serve several farms because it can collect large quantities of water and silt useful for agriculture. This type of barrier is used in mountainous areas with active wadis in the Emirate of Fujairah. The length of this type of earth barriers is more than 10 m and its height is 4 m; they are mostly found in the eastern agricultural region. Photos 20.1 and 20.2 illustrate the earthen barriers in Wadi Al Furfar in Fujairah Emirate and show the positive impact of these barriers on the prosperity of the agricultural activity in the region. 20.2.1.3  Habisas A “habisa” or confiner is a low-lying area in wadi floor where water collects naturally. Then, people build walls around the undulating earthen water runoff or leakage. Habisas usually assumes a circular or rectangular shape. Examples of famous habisas are Al Bithna in Fujairah Emirate and Al Mawrid in Ras Al Khaimah Emirate. Habisas play a major role in agricultural activities in the country, where they were used as a key technology for rainwater harvesting long ago and are still used today in booming agricultural areas, especially palm plantations. Small habisas, ranging in diameter between 5 and 10  m, are efficient in areas suffering from drought and scarcity of rainfall.

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Photo 20.1  One of earthen barriers in Wadi Furfar, Northern Agricultural Area, Ras Al Khaimah Emirate

Photo 20.2  Impact of an earthen dam on agriculture in Wadi Furfar, Ras Al Khaimah Emirate

The use of a small habisa in saving flood water and recharging groundwater is shown on Photo 20.3. The water stored in habisas contributes to the rise of hydraulic heads and improvement of groundwater quality, providing water for agriculture during rainy periods and during dry seasons form the large quantities of water stored during flood events.

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Photo 20.3  Habisat Wadi Al Mawrid, Ras Al Khaimah Emirate

The diameters of large habisas range from 20 to 50 m, built in the course of the main wadi to feed many farms at the same time, in addition the surrounding villages. In these areas, Habisas used to be the primary source water for domestic and agricultural activities. Habisas in the Eastern Region, such as Habisat Al Bithna, have led to development of a large city and noticeable agricultural activities in this area, which now has more than 125 palm plantations, fruits and fodder crops. 20.2.1.4  Berkas “Berkas“, or ponds, are underground concrete structures of rectangular shape of lengths ranging from 6 to 10 m and with storage capacities varying between 1000 and 50,000 m3. Farmers build berkas in mountainous areas in order to collect the maximum possible quantity of water for use in various activities. The most famous wadis having berkas are Al Bih, Al Naqab and Quda’a in Ras Al Khaimah Emirate. Small berkas store most of the water flowing downgradient from the mountains. Afterwards, collected water in these berkas is used for all purposes. The volumes of small berkas range from 1000 to 20,000 m3. Large berkas meet water needs of small communities in mountainous regions, especially in Ru’us Al Jibal in the northern part of the country. Photo 20.4 shows a small berka in Wadi Qada’a. The Emiratis have built berkas ranging in size from

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Photo 20.4  Small berka basin for harvesting of rainwater in Wadi Naqab, Ras Al Khaimah Emirate

20,000 to 50,000 m3. Berkas are man-made, underground storage tanks, lined with cement to prevent water seepage, storing water for more than 5 years and mainly used for drinking. Local residents relied on the water of berkas for various activities such as agriculture, drinking and domestic uses. Berkas are one of the characteristic features of Wadi Qada’a and Wadi Al Naqab in Ras Al Khaimah Emirate. People living in many villages within both wadis consistently maintain berkas, which are used regularly all year around.

20.2.2  Groundwater Harvesting 20.2.2.1  Aflaj Systems The “Falaj“is a man-made channel or tunnel, intercepting groundwater at the foothills of mountains and brings it to the surface at a lower level for irrigation without mechanical means. The aflaj systems were discussed in detail in Chap. 8. The aflaj system is one of the oldest irrigation methods in the world. The aflaj are known all over the world, where it extends from China in the Far East, across the Arabian Gulf region, Iran, North Africa, Spain and the Americas, constituting the oldest free market economy in history.

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Construction of aflaj aims at harvesting a part of shallow groundwater near the foothills of mountainous areas and bringing this water to the ground surface for irrigation purposes (Rizk 1998). Aflaj channels are designed as deep and narrow trenches to minimize natural evaporation, which is high in the region. Water of a large number of falaj Al Daudi and Al Hadouri circulates to farms through man-­made tunnels. Al Adrous (1990) classified aflaj systems, based on their discharge, into three types: Gheli, Daudi and Hadouri. Aflaj Al Gheli usually carries water during the rainy season only (November to March). Despite the fact that aflaj Gheli provide a limited water supply, the water is usually of excellent quality (Wilkinson 1981), because they are mainly fed from rainwater (Photo 20.5). In contrast, groundwater is the main source of water carried by aflaj Al Daudi (Photo 20.6 and Table 8.1). The discharge of aflaj Al Daudi remains constant throughout the entire year and seldom exhibits variation over time. The discharge of aflaj Al Hadouri comes from deep artesian aquifers in which water moves upward under hydrostatic pressure, as the aflaj systems intercept such water and carry it through their tunnels towards date palm farms for irrigation. As a results of excessive pumping of groundwater near their recharge areas, several aflaj systems have ceased to flow in the present (Photo 20.2). Aflaj discharge, despite its small amount, still represents an important, renewable source of water. During the period 1994–2010, aflaj discharge varied between 9.0 Mm3 in 1994 and 31.2 Mm3 in 1982.

Photo 20.5  Falaj Al Mawrid Ras Al Khaimah belongs to aflaj Al Gheli. The falaj discharge increases during the rainy season and decreases, or may become nil, in the absence of rain

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Photo 20.6  Falaj Al Qattara in the Al Ain area, belongs to aflaj Al Daudi. The falaj used to depend on shallow groundwater in the western gravel aquifer, but it is now dry because of excessive groundwater pumping

20.3  Modern Water Harvesting Methods 20.3.1  Surface Water Harvesting 20.3.1.1  Cloud Seeding The National Center for Atmospheric Research of Colorado in the United States tried cloud seeding and conducted a study of artificial precipitation in the UAE, using special airplanes for this atmospheric survey in the country. The study was conducted during 2001–2002 for four seasons total, each season lasting 3 months. Two seasons were in winter, during the January–March period, and the other two seasons were in summer during the period July–September. The survey covered the entire UAE and also extended to surrounding countries. The objectives of the study were to identify the chemistry and composition of the atmosphere, the nature of the processes leading to rainfall, the physical properties of clouds and the possibility of increasing rainfall. The results of this research study were published during 2002 and 2003 (Breed 2002; Bruintjes 2002; Jensen 2003; Salazar 2003). Results show that the eastern mountain ranges in the UAE witness the largest accumulation of clouds, despite variations in cloud characteristics from one season

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to another and even during the same season. In winter, clouds were stratiform clouds of smaller particle size (200–600  cm3) and moisture content (0.1–0.4 gm/cm3), while summer clouds had larger sized particles (400–1000 cm3) and more moisture content (0.4–1.2 gm/cm3). The main source of condensation nuclei was the dust caused by wind in desert areas, with their scarce vegetation and prevailing arid climate. Some condensation nuclei were in the form of sodium chloride (NaCl), and others were sulfur compounds resulting from pollution. The results indicated that the best time for cloud condensation and increasing rainfall through inducing artificial condensation is the end of the winter season, between March and April. Results also showed that the chances for successful cloud seeding during the summer are better than during winter because the raindrops are larger in summer than winter. Also, the cloud moisture content may reach 100% in some areas during the summer. 20.3.1.2  Artificial Rain The Water Resource Studies Department in the Office of His Highness the UAE President conducted a study in collaboration with the NASA’s Marine Research Laboratory, on fine suspended particles in the atmosphere of the UAE desert, and its influence on weather and climate. The study was conducted during the period from 5 April to 30 September 2001, with the participation of 20 research laboratories in America, Europe and South Africa. Special airplanes, satellites and several computer models were used to understand the complex atmospheric cycle and mixing of desert dust with smoke and other minute particles. The results of those studies indicated mixing of the smoke coming from the Indian subcontinent with the dust from the Arabian Desert, which was monitored with ten satellites, six computer models, research airplanes and marine research vessels, in addition to 70 experts and ten institutions around the world. The fine, suspended particles in the atmosphere represent a mystery that holds the secrets of how the climate works. The fine, light particles in the atmosphere reflect heat and sunlight and has cooling properties, while fine, dark particles absorb heat and light and heat up the atmosphere. The NASA mission to the UAE measured the characteristics and movement of fine particles and whether it increases or decreases the temperature of the atmosphere. Scientists also tried to explain the complex climatic phenomena in coastal areas of the Arabian Gulf and Gulf of Oman. Experts can improve the results of computer models about the climate and prediction of climatic conditions as a result of changing concentration of particles through obtaining accurate data on how the fine, suspended particles in the atmosphere act. NASA began the task from space using its satellites Tierra (Terra) and Aqua (Aqua), in addition to other satellites. Satellites data were compared with the land-based remote-sensing equipment, regarding mineral dust and pollutants collected by 15 devices placed on land and in the sea. The researchers used airplanes and satellites data to calibrate the regional and international climatic data, regarding movement of particles in the atmosphere.

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The Arabian Gulf region represents a challenge for the climate experts, who are trying to simulate climatic conditions using computer models, because the wide variation in geomorphic features. The climatic conditions can range from a small cloud and a great number of complicated thunderstorms. The MAARCO airplanes enabled experts at the University of Warsaw in Poland to study the effect of fine particles suspended in the atmosphere on incident solar radiation, the hydrologic cycle and energy balance in an area of scarce rainfall. This project complements the efforts of understanding the climate in this area of the world, which is characterized by high temperatures and aridity, in contrast to the Indian subcontinent, which is known for summer storms. The Water Resource Studies Department in the Office of His Highness the UAE President provided wide logistic support, including the use of five radar climate-monitoring stations and 50 other climatological stations. 20.3.1.3  Recharge Dams The study of topographic maps, aerial photographs and satellite images of the eastern mountain ranges in the UAE revealed the presence of 70 drainage basins, 60 of which are within the UAE and 48 that are in the northern part of the country (Rizk and Alsharhan 2008). The catchments areas of these basins vary between 5 km2 at Wadi Dednah in Fujairah and 475  km2 at Wadi Al Bih in Ras Al Khaimah (MOEW 2010). To harvest a good part of flood water, the Ministry of Climate Change and Environment (MOCCAE), the former Ministry of Environment and Water (MOEW), constructed a series of 114 multi-purpose dams since early 1980’s (Fig. 3.4). The UAE is continuing to construct recharge dams to make use of each drop of precious flood water. The MOCCAE plan is to build 68 additional recharge dams in the future. The new dams’ main function is to divert a large part of flood water downward, recharging groundwater and increasing freshwater reserves. Out of the new 68 new dams, 54 are proposed for the northern mountainous emirates with a total storage capacity of 2.7 Mm3. About 29 of the new dams will be in Fujairah, 19 in Ras Al Khaimah, five in Sharjah and one in Umm Al Quwain (MOEW 2010, 2015). Now the MOCCAE directly manages 66 of the 114 dams, with the main purpose of harvesting flash-flood water which was formerly wasted by flowing either into the Gulf of Oman in the east or through evaporation in desert plains in the west (Photos 20.7, 20.8, 20.9, 20.10, 20.11, 20.12, 20.13 and 20.14). These dams feed groundwater by diverting a good part of runoff water towards underlying aquifers. In addition to aquifer recharge, dams increase groundwater levels, slow down salt-water intrusion into coastal aquifers, provide a surface water source for irrigation and drinking, protect homes, roads and farms against the risk of flash floods, conserve agricultural land and minimize soil erosion in downstream areas. Groundwater recharge dams in the UAE make it possible to take advantage of sediments accumulating behind dams to improve agricultural soils. Dams also improve climate in their areas and promote tourism.

20.3 Modern Water Harvesting Methods

Photo 20.7  Reservoir of Wadi Ar Rafisah Dam, Wadi Shi, Fujairah Emirate, as of May 2006

Photo 20.8  Reservoir of Wadi Safad Dam, Fujairah Emirate, as of March 2006

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Photo 20.9  Reservoir of Wadi Shawkah Dam, Ras Al Khaimah Emirate, November 2004

Photo 20.10  Reservoir of Wadi Al Wurayah Dam, Fujairah Emirate, as of October 2004

20.3 Modern Water Harvesting Methods

Photo 20.11  Reservoir of Wadi Al Ruheib Dam, Fujairah Emirate, as of October 2004

Photo 20.12  Reservoir of Wadi Al Tawiyean Dam, Fujairah Emirate, as of October 2004

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Photo 20.13  Reservoir of Wadi Al Bih Dam, Ras Al Khaimah Emirate, as of October 2004

Photo 20.14  Reservoir of Wadi Al Baseerah Dam, Fujairah Emirate, as of October 2004

The total volume of water harvested by large and small dams and barriers until December 2005 was approximately 160 Mm3 (Rizk and Alsharhan 2003; Rizk and Alsharhan 2008). Dams played an important role in recharging groundwater, as indicated by the rise of groundwater levels in some observation wells behind many dams (Fig. 6.21).

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The role of dams in groundwater recharge was investigated by Sherif et al. (2006) and Sherif et al. (2011). Sherif et al. (2017) quantified the groundwater recharge induced by Wadi Al Bih, Wadi Tawiyean and Wadi Ham in northeastern UAE. The 3D MODFLOW was calibrated and validated, using two independent datasets in each area, to simulate groundwater flow and recharge from rainfall. All simulations were conducted in the 3D horizontal view, and a recharge coefficient of 0.2 was used. The calculated recharge efficiencies of Wadi Ham, Wadi Al Bih and Wadi Tawiyean are 47%, 31% and 22%, respectively. Wadi Ham dam has the highest efficiency compared to Al Bih and Al Tawiyean dams because the geologic ­structures affect the reservoir area, increasing the aquifer’s secondary porosity and hydraulic conductivity. Large amounts of recharge water are trapped in the unsaturated zones, increasing soil moisture content. In spite of the scarcity of rain in the UAE, most of the seasonal flood water in the past was lost through natural evaporation or direct discharge into the sea. So, it has been found that the most appropriate type of dams for the climate conditions prevailing in the country is temporary detention dams. The former MOEW has implemented many dam projects in cooperation with international companies with considerable experience in the field. These dams were built in accordance with international standards. The MOEW summoned experts to review the safety of dams and their performance and conformity with the design reality. The technical people of the ministry also monitor the engineering and technical conditions of dams and evaluate their effectiveness through the records of monitoring wells scattered behind these dams in groundwater-recharge areas. To further ensure the effectiveness of the performance of dams in groundwater recharge, the MOEW conducts regular surveys on these dam sites by specialized companies. The results of these field surveys revealed valuable information on the subsurface formations and aquifers’ hydraulic properties and the contribution of dams to groundwater recharge. Results confirmed the effectiveness of dams in groundwater recharge and improving groundwater quality (Table 20.1).

20.3.2  Groundwater Harvesting 20.3.2.1  Artificial Recharge Artificial recharge of groundwater involves feeding depleting aquifers from various sources, such as flood water, desalinated water and treated sewage water. Recharge occurs through injection of water into aquifers through a prechosen method such as dams, water-spreading ponds, surface-water seepage, rainfall, permanent or seasonal surface water courses and the injection-well method (Abdulrazzak 1997). Artificial recharge stores water in the subsurface for future use, including bringing the water to be stored, the choice of an injection method and the study of steps and methods of implementation. Artificial recharge for groundwater causes

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Table 20.1  Data of groundwater recharge dams in the UAE, obtained from the Ministry of Climate Change and Environment Elevation (m) 16.0

Length (m) 2800

Reservoir capacity (Mm3) 7.70

Water quantity (Mm3)a 27.005

Ras Al Khaimah Ajman

18.0

220

7.50

44.567

8.00

235

0.25

4.505

10.0

110

0.50

9.713

4.50

26.0

0.015

0.206

11.0

850

3.00

7.667

No. 1

Name of the Dam Ham

2

Bih

3

Gulf

4

Eden

5

Gheil

6

Hadf

Ras Al Khaimah Ras Al Khaimah Ajman

7 8

Zikt Tawiyean

Fujairah Fujairah

18.0 23.5

230 342

3.50 18.5

17.880 34.705

9

Wurrayah

Fujairah

33.0

367

5.20

9.430

10

Baseerah

Fujairah

8.00

885

1.60

3.450

Emirate Fujairah

Benefited areas Fujairah and Kalba Buraiyrat and Nakheel Mezaria and Masfut Eden and Hamraniyyah Gheil Mezaria and Masfut Dednah Tawiyean, Hamraniyyah and Khatt Bedia and Khor Fakkan Dibba

The water quantity retained by the dam since established

a

a rise of groundwater levels in depleting aquifers, stores excess water during rainy season until the time when it is needed and slows down salt-water intrusion into fresh aquifers. Freshwater storage in a brackish aquifer was simulated by Sherif and Shetty (2013), with the use of MODFLOW. The simulations investigated the long-term injection and recovery of freshwater from a brackish aquifer at Wadi Ham area, in the Eastern Region of the UAE. Results showed that the recovery efficiency ranged from 32 to 88%, with high recovery efficiency during the early cycles and a gradual slowdown in the subsequent runs. Hussain et al. (2016) simulated the efficiency of artificial recharge of a coastal aquifer using treated wastewater to control salt-water intrusion. The results of model simulations revealed that artificial recharge of the eastern gravel aquifer at Wadi Ham decreased groundwater salinity. The recharged water maintained the seaward gradient by raising the aquifer’s hydraulic heads. For this reason, it seems that a simple surface-recharge basin, collecting treated wastewater and/or flood water can represent a good solution to salt-water intrusion problem in Wadi Ham area, and it could sustain water resources in the simulated aquifer system.

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625

20.3.2.2  Aquifer Storage and Recovery Abu Dhabi Emirate embarked on the largest project in aquifer storage and recovery (ASR) in the world, where the stored water volume averaged 10 Mm3 per year, in the Liwa Quaternary sand aquifer. The project involved injection of desalinated water into the aquifer system and its subsequent recovery according to various scenarios. Stuyfzand et  al. (2017) modeled two scenarios. Scenario (A) predicted a water-quality change after 2.5 years, and scenario (B) after 10 years. Results of scenario (A) in modeling simulation showed that in recovered water the quality will still meet drinking-water standards for the Emirate of Abu Dhabi, while the recovery rate reached 85%. In scenario (B) simulations, the recovery efficiency decreased to 60%, and presence of metals exceeded the Abu Dhabi drinking-water standards, especially the one for chromium. Exceedances are expected for sodium (Na), arsenic (As), chromium (Cr) and iron (F) as a result of the mixing of injected desalinated water with native groundwater in the aquifer. Aquifer storage and recovery (ASR) is a proven technology for storing large volumes of water (Maliva and Missimer 2003). The aquifer storage and recovery (ASR) means storage of excess water in a suitable aquifer via wells at depths varying between 60 and 900 m and retrieval of such water from the same wells when needed. The use of this technique is meant to address the imbalance between water availability and water need, seasonally, annually or in the long term. In some areas, surplus water is stored during years of heavy rains to be exploited and used during relatively dry years, in a process called “Water Banking”. In some cases, the technique is used for recharging aquifer when water quality is high and its subsequent retrieval when other available sources of water are of lower quality. The ASR technology is also used to store drinking water, and, when this water is recovered, it is directly injected into water distribution networks without any treatment other than disinfection. In many places where this technique is used, high-­ quality water is stored in an aquifer overlain or underlain by low-quality supplies. The ASR is also used to store flood water after treatment to avoid blockage of injection wells. This water is treated again after retrieval and before pumping into water distribution networks to meet drinking water standards (WHO 1984). The ASR involves fresh, brackish or saline artesian aquifers. The used aquifers include limestone, dolomite, sand, sandstone, basalt, gravel and glacial deposits. It is common now to store treated-sewage water during the winter or when less irrigation water is needed. This water is recovered during the summer when there is a high demand for irrigation water. The ASR method can be widely used in the UAE to store water desalinated by the use of reverse osmosis (RO) technology, either for removing salts or for water softening. Practical experience has proved that combining desalination and the ASR technology is economically feasible. Water desalination plants always work at a constant rate. Surplus water is stored during ordinary times and retrieved when needed. The US is the number one country applying ASR technology: there are already 40 fields of ASR, in addition to a 100 more in various stages of construction.

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Australia has six working fields in addition to others under construction. The UK has two operating fields and two others under construction. The wide expansion in this technology results from the advantages it has in limiting salt-water intrusion, preventing land subsidence, improving the quality of stored water and maintaining pressure and flows in water-distribution systems. It also provides water needed during emergency situations, in addition to several other uses. The recovery efficiency is high and can reach 100%. To assure a full recovery of stored water, a buffer zone of injected water is added immediately as soon as injection wells start working. The volume of water in the buffer zone depends on aquifer thickness, effective porosity, transmissivity, water quality, the degree of confinement, diversity and the volume of water retrieved. Abu Dhabi and Sharjah emirates have already started their own ASR projects. Abu Dhabi Project As indicated earlier, a pioneering ASR project was carried out in 2002, where desalinated water was injected into the Liwa Quaternary sand aquifer in the western region of Abu Dhabi Emirate, near Madient Zayed. However, after the construction of the largest desalination plant in the UAE in Qedfa’a area, Fujairah Emirate in 2003, a feasibility study of ASR projects was conducted, and another ASR test project was carried out in the Al Shuaib area. Both the ASR projects at Liwa and Al Shuaib areas have been successful—with a proven recovery efficiency of about 85% (Fig. 20.1). Abu Dhabi Emirate relies on desalinated water as the main source for domestic purposes, and the produced water is stored in tanks for use. But, the amount of freshwater produced is larger than the storage capacity of available tanks, especially

Fig. 20.1  Locations of ASR pilot projects in the Abu Dhabi Emirate

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627

in winter months when the production exceeds the consumption. This surplus water is now applied for landscaping and irrigation of forests, public parks and green spaces throughout the Emirate of Abu Dhabi. A highly feasible alternative would be to store this excess freshwater in aquifers during the winter months and recover it in summer. To maintain an uninterrupted supply during emergency, the Emirate needs to have long-term storage capacity. Two sites were selected for ASR and two pilot projects were carried out starting in 2002. The first one is in Shuaib in Eastern Region and the other is in the Western Region as shown in Fig. 20.1. In the Al Shuaib project, desalinated water from the Qedfa’a desalination plant was injected into the western gravel aquifer, which is seriously depleted (Fig. 16.1; this Volume). The results obtained from this test site indicate that ASR is a highly feasible alternative for recovery of the intensely exploited aquifer systems in the UAE (Dawoud 2009). The second ASR project is located between Madinat Zayed and Mezaria area in the Liwa Crescent. The project was designed for injection of 500 m3 per hour (m3/h) and recovery of 750  m3/h. The Liwa Quaternary sand aquifer north of the Liwa Crescent was selected because this aquifer is a large natural fresh water  lens (TDS ≈ 1000–1500 mg/L). The aquifer is heavily exploited at the present, while its water is basically nonrenewable (Wood et al. 2003). The aquifer is homogenous; has sufficient lateral extension, thickness and depth of groundwater table; favorable hydrochemical conditions; and is located far from other well fields. In conclusion, the ASR consisting of injecting fresh desalinated water into the Liwa Quaternary sand aquifer in the western region of Abu Dhabi Emirate and its recovery in good quality and high percentage (85%) is feasible. Sharjah Project The Sharjah Electricity and Water Authority (SEWA)’s Nezwa project is 400-­million imperial gallons (MIG) of storage of freshwater in the Emirate of Sharjah by ­utilizing ASR technology for the primary objective of storing the excess desalinated water during the low-demand periods and utilizing it during the high-demand ones (Fig. 20.2). The collected data from the project site was compiled and assimilated into two databases: one linked to Geographical Information Systems (GIS) for surface features and land-use data, and the other to Schlumberger Water Services (SWS) geomodeler Petrel™ and HydroGeoAnalyst (HGA) for the hydrogeological data. SEWA targeted a working ASR system of 30 MIGD to test the aquifer zones and to prove its capability to handle the 400 MIGD ASR project (Almulla et al. 2005). Four cycles (injection/storage/recovery) were applied with efficiencies of 45.3%, 65.8%, 74.2% and 94.4%, respectively. The integration, data testing and simulation through modeling resulted in a model with these scenarios: 4 months’ injection at 5.5 MIG/day (25,000 m3/day); 5 months’ recovery at the same pumping rate; and a 2 months’ storage period with 35 wells. Therefore, several million m3 of water can be injected into and subsequently recovered from the ASR sites.

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Fig. 20.2  Locations of ASR pilot project in Nizwa, Sharjah Emirate

20.3.2.3  Subsurface Dams Subsurface dams are built in many dry areas in Africa, India and China (Hanson and Nilsson 1986). In Japan, the subsurface dam of Miyakojima Island with a storage capacity of 20 Mm3 of groundwater is pumped at a rate of 50,000 m3/day through 147 well (Nagata et al. 1993). The subsurface dams store groundwater in the pores of earth layers to be used in a sustainable manner when needed. Unlike surface dams, the subsurface dams store water in the subsurface and are not subject to collapse. The land surface in the dam site is utilized after dam construction. Subsurface dams are constructed in areas where fresh groundwater can mix with lower- quality water, leading to quality degradation. Subsurface dams are also constructed to prevent salt-water intrusion in fresh aquifers in coastal areas. Subsurface dams prevent large evaporation rate from artificial lakes behind surface dams, especially in dry desert areas where natural evaporation reaches record levels. The annual evaporation rate in the UAE reached 3322 mm, and the mean annual rainfall is 119 mm, which means that evaporation is a factor of 28 more than rainfall. Subsurface dams limit fluctuations in groundwater levels and prevent dryness

References

629

of wells under heavy pumping of groundwater. Subsurface dams are not exposed to erosion and silting as in surface dams. Subsurface dams store additional quantities of water because the effective porosity of the aquifer storing water in front of the dam remains high. The body of the subsurface dam must rest on an impermeable layer, so that the stored water does not leak. Pumping of groundwater stored in front of subsurface dams requires high expenditures to drill a large number of wells. There is difficulty in estimating the amount of groundwater stored in front of a subsurface dam. The effective porosity responsible for water storage is hard to calculate and varies in time and space. The amount of water in storage and the volume of water leakage are also hard to quantify. In the UAE, although there are a large number of water wells tapping the western gravel aquifer in the Eastern Region of Abu Dhabi Emirate, about 70,000  m3 of fresh groundwater is moving westward and mixes with the saline water, making it unsuitable for drinking or agriculture. Silva and Al Noaimi (1999) crafted a numerical groundwater-flow model to assess strategies for pumping such high-quality water before mixing with low-quality water. One of the recommendations based on the model results is to construct a subsurface dam 80-m deep and 17-km long, in order to raise the groundwater level between 1 and 20 m. The idea of constructing subsurface dams across the courses of buried alluvial channels, carrying fresh groundwater from the eastern mountain ranges in the UAE further west, are worth serious evaluation in the future.

References Abdulrazzak MJ (1997) Water supply augmentation through artificial groundwater recharge techniques. In: Proceeding of the third Gulf water conference  – towards efficient utilization of water resources in the Gulf, Muscat, Sultanate Oman, pp 241–281 Al Adrous MH (1990) Falajes of the Al Ain-first edition. Al Motanabi Publication, Abu Dhabi, p 109. (in Arabic) Almulla A, Hamad A, Gadalla M (2005) Aquifer storage and recovery (ASR), a strategic cost-­effective facility to balance water production and demand for Sharjah. Desalination 174:193–204 Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an arid region: the Arabian gulf and adjoining areas. Elsevier Publishing Company, Amsterdam, 331 p Breed D (2002) Aerosol and cloud droplet measurements in the United Arab Emirates. In: 11th conference on cloud physics American meteorological society Ogden, Utah, USA, p 6 Bruintjes R (2002) Microphysical and radioactive properties of clouds in the United Arab Emirates and adjacent regions. In: 7th scientific conference of the international global atmospheric chemistry project on atmospheric chemistry in the earth system: from regional pollution to global climate change, Crete, Greece, p 4 Dawoud MA (2009) Challenges and opportunities of using renewable energy sources for desalination of brackish groundwater in the Arab regions. In: International desalination world congress, Dubai, UAE, p 14 Hanson G, Nilsson A (1986) Ground-water dams for rural-water supplies in developing countries. Groundwater 24(4):497–506

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Hussain MS, Javadi AA, Sherif MM (2016) Artificial recharge of coastal aquifers using treated wastewater to control salt-water intrusion. In: Proceedings of the 24th UK conference of the association for computational mechanics in engineering 31 March–01 April, Cardiff University, Cardiff, p 5 Jensen T (2003) Observed cloud characteristics during hygroscopic cloud seeding research in the United Arab Emirates. In: 8th WMO scientific conference on weather modification world meteorological organization, Casablanca, Morocco, p 7 Maliva R, Missimer T (2003) Aquifer storage and recovery to improve efficiency and economics of water projects. In: IDA world congress on desalination and water Reuse, Bahamas MOEW (Ministry of Environment and Water) (2010) Water Conservation Strategy: Ministry of Environment and Water, p 212 MOEW (2015) State of the environment Report—United Arab Emirates. Ministry of Environment and Water, p 36 Nagata S, Enami N, Nagata J, Katho T (1993) Design and construction of cutoff walls for subsurface dams on Amami and Ryukyu Islands in the most southwestern part of Japan. Hydrogeol Sel Pap 4:229–245 Rizk ZS (1998) Falajes of United Arab Emirates: Geological Settings and hydrogeological characteristics. Arab J Sci Eng King Fahd Univ Petrol Mineral Dhahran Saudi Arab 23(1C):3–25 Rizk ZS, Alsharhan AS (2003) Water resources in the United Arab Emirates. In: Alsharhan AS, Wood WW (eds) Water management perspectives: evaluation, management and policy. Elsevier Science, Amsterdam, pp 245–264 Rizk ZS, Alsharhan AS (2008) Water resources in the United Arab Emirates. Ithraa Publishing and Distribution, Amman, p 624. (in Arabic) Salazar V (2003) Aerosol-cloud interactions in the United Arab Emirates. In: 5th conference on atmospheric chemistry. gases, aerosols, and clouds American meteorological society, Long Beach, California, USA, p 7 Sherif M, Ebraheem A, Shetty A (2017) Groundwater recharge from dams in United Arab Emirates. In: World environmental and water resources congress: ASCE, pp 139–146 Sherif M, Al MA, Garamoon H, Kasimov A, Akram S, Ebraheem AM, Shetty A (2006) Geoelectrical and hydrogeochemical studies for delineating ground-water contamination due to salt-water intrusion in the outlet of Wadi Ham, UAE. Environ Geol 49(4):536–551 Sherif M, Mohamed M, Shetty A, Almulla M (2011) Rainfall-runoff modeling of three wadis in the northern area of UAE. J Hydrol Eng ASCE 16(1):10–20 Sherif M, Shetty A (2013) Freshwater storage in brackish aquifers. In: World environmental and water resources congress 2013, pp 440–449 Silva E, Al Noaimi F (1999) Digital simulation of groundwater salvage in northeastern Abu Dhabi Emirate. In: Proceedings of 4th Gulf water conference, 13–17 February, 1999, Bahrain, pp 303–316 Stuyfzand PJ, Smidt E, Zuurbier KG, Hartog N, Dawoud MA (2017) Observations and prediction of recovered quality of desalinated seawater in the strategic ASR project in Liwa, Abu Dhabi. Water 2017, 9, 177, p 25 WHO (World Health Organization) (1984) WHO guidelines for drinking water quality. Volume 1, recommendations. Geneva, p 130 Wilkinson JC (1981) Falajes as means of irrigation in Oman: Ministry of National Heritage and Culture, Sultanate of Oman, p 129 Wood WW, Rizk ZS, Alsharhan AS (2003) Timing of recharge, and the origin, evolution and distribution of solutes in a hyper arid aquifer system. In: Alsharhan AS, Wood WW (eds) Water resources perspectives: evaluation, management and policy, Developments in water science, vol 50. Elsevier, Amsterdam, pp 245–264

Chapter 21

Advanced Agricultural Technologies

Abstract  Irrigated agriculture consumes 60% of water resources in the UAE. As groundwater is the main source of irrigation water, exploitation of aquifer systems in excess of natural recharge has led to serious depletion and salinity problems. Biosaline agriculture might contribute to integrated water-resource management because it enables the use of two marginalized resources; salt water and saline soils. If salt-tolerant crops were to grow using salt water in saline soils, additional food could be produced, and desert land could be counted as agricultural area. In this respect, local and foreign varieties of crops are being researched now to identify salt-tolerant species through the efforts funded by the International Center for Biosaline Agriculture (ICBA) in the UAE, which is a unique institution of its kind in the region. Replacement of traditional irrigation methods by modern irrigation techniques such as drip, sprinkler and bubbles in 90% of farmlands in the country have saved considerable amounts of irrigation water and increased crop productivity. Sustainable farming of organic products is a promising alternative for conventional crops using considerable chemical fertilization because it meets the growing market needs and receives full support from the government. The chapter discusses protected agriculture, the role of the ICBA in the UAE, aquacultures and hydroponics, environmental impacts of agriculture and agricultural policies.

21.1  Introduction Irrigated agriculture is the major water consumer in the world. The average irrigation water consumption in the Arabian Gulf region is about 77%, varying from 68.2% in the UAE and 84.8% in the Sultanate of Oman (Table 2.39 and Fig. 21.1). The average rate of irrigation water in the region increased from 18 Bm3 in 1990 to 22 Bm3 in 2000. Expansion of agricultural activities increased irrigation water demand, which comes primarily from groundwater, has led to a substantial increase in the groundwater pumped from various aquifers. Groundwater extraction in the © Springer Nature Switzerland AG 2020 A. S. Alsharhan, Z. E. Rizk, Water Resources and Integrated Management of the United Arab Emirates, World Water Resources 3, https://doi.org/10.1007/978-3-030-31684-6_21

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Fig. 21.1  Sectoral water consumption. (After Al Awar 2014)

UAE greatly exceeded the natural recharge, leading to aquifers’ depletion in many areas. Rapid expansion of irrigated area has resulted in groundwater mining on a large scale (Bazza 2005). The UAE experiences water shortage and rapid aquifers’ depletion because the groundwater exploitation rates are continually increasing. If salt-tolerant crops were grown using salt water in saline soils, additional food for human and animals could be produced and desert land could be counted as an agricultural area. Furthermore, the use of saline water relieves pressure on exhausted freshwater resources (Al Attar 2002). Biosaline agriculture might contribute to integrated water-resource management because it enables the use of two marginalized resources: salt water and saline soils. Local and foreign varieties of crops are being researched now to identify salt-­ tolerant species through efforts funded by the ICBA in the UAE, which is a unique institution of its kind in the region. The UAE comprises three ecological regions: coastal areas, sand and gravel plains and eastern mountain ranges; 74% of the UAE is covered by sand-dune fields, particularly the western region (MOEW 2006). During the period 1994–2003, the agricultural area tripled and reached more than 2607 km2. Table 21.1 shows that the cultivated area in 2003 was around 2549 km2, including, 9% shifting areas, 16% annual crops and 75% permanent crops. The National Bureau of Statistics (2015) data indicates that the crop area in the UAE increased about 4%, from 793,969 donums in 2013 to 827,430 donums in 2015, and Abu Dhabi Emirate contained about 75% of the total crops area, followed by the Emirate of Ras Al Khaimah Emirate, which formed 17%. The cropland of vegetables in Abu Dhabi is the highest in the country, forming 37% of vegetables crop area in the country, and the second emirate in vegetables area was Ras Al Khaimah, with 34% (Table 21.2). Farming is the main economic activity in the East Coastal region of the UAE (Tables 21.3 and 21.4). Historically, the area was known as the fruit basket of the

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Table 21.1  Cultivated area (in hectare = 10,000 m2) per emirate in 2003 in the UAE (based on data from FAO 2008) Emirate Palm tree Permanent crops Crop and Fodder Vegetables Greenhouses Shifting area Cultivated area

Ras Al Fujairah Khaimah 2258 3762 978 1066

Umm Al Quwain 385 182

Abu Ajman Sharjah Dubai Dhabi 502 4824 1519 172,080 357 1551 584.0 340.00

Total 185,330 5058

359

2419

289

248

1599

804.0 24,719

30,437

721 19.0 860 5193

2446 55.00 3498 13,246

176 2.00 334 1367

184 2.00 682 1975

1667 23.00 3244 12,909

750.0 3.00 2257 5917

9769 247.0 24,077 254,918

3826 144.0 13,202 214,311

Table 21.2  Distribution of land use (area in Donum = 1000 m2) by emirate in the UAE in 2015 (after National Bureau of Statistics 2015)

Crop Fruit Trees Crops and Fodders Vegetables Temporary Fallow Forests Other Land Total

Emirate Abu Dhabi Dubai Sharjah Ajman 272,322 14,946 37,143 5649 48,177 3156 6646 1550

Umm Al Quwain 6347 2717

Ras Al Khaimah 29,990 13,504

Fujairah 20,224 386,620 3628 79,378

19,355 1615 281,300 1640

553 1209

13,365 18,052

3043 4994

43,371 318,061

129.0 23,264 98,304

102.0 4362 36,352

18,680 178,070 1,024,181

4980 8920

460.0 1946

Total

16,702 675.0 511.0 425.0 136.0 112,011 16,106 16,052 2784 3492 749,868 38,137 74,252 12,813 14,454

country, producing mangos, dates and bananas (Al Qaydi 2014). In recent years, with the increasing population-growth rate, sustainable farming has become a major challenge for East Coast farmers, who need financial support to meet that growing demand for food, while preserving the environmental integrity. The idea of using the traditional organic methods of fertilizing and pest control needs to be promoted among East Coast farmers who can use natural fertilizers produced in their organic farms to reduce the import of manufactured soil, chemical fertilizers and pesticides. Sustainable farming of organic products is a promising alternative to conventional crop methods that use chemical fertilization because it meets the growing market demands (Al Qaydi 2014) and receives full support from the government (MOEW 2015).

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Table 21.3  Distribution of farm land use (area in Donum = 1000 m2) in the East Coast area of the UAE (after Al Qaydi 2014)

Crop Fruit Trees Crops and Fodders Vegetables Forests Temporary Fallow Other Land Total

East Coast 31,464 7365 4665 210.0 3092 8992 55,788

UAE 433,979 226,547 50,181 29,732 174,176 137,956 1,052,571

Table 21.4  Estimated distribution of farms and water wells in the Eastern Region of the UAE in 2012 (After Al Qaydi 2014) Region Dhadnah Dibba Fujairah Kalba Khor Fakkan Masafi Murbih Total

Well active 400.0 1150 280.0 870.0 350.0 490.0 510.0 4050

inactive 250 70.0 150 400 230 97.0 25.0 1222

Farm active 330.0 1000 450.0 528.0 420.0 1100 300.0 4128

inactive 170 54.0 40.0 330 474 70.0 190 1328

21.2  Agriculture and Food Production Tables 21.5 and 21.6 show that the total number of farms in the UAE in 2003 was 38,548. Abu Dhabi Emirate has 60% of the farms in the country, 16% of farms are shared by other emirates in the central and eastern areas and 24% of farms are in the northern UAE, mostly in the Emirate of Ras Al Khaimah. FAO (2008) reported that UAE farms produce vegetable crops, fodder and date palms. The Government of Abu Dhabi buys the fodder production from farmers, while the fodder production of other farms is exported to neighboring countries or sold in the local market. The UAE Government buys the production of date and vegetable crops from farmers all over the country at a competitive price, depending on quality. Agriculture is one of the major aspects of cultural heritage in the UAE. Traditional agricultural activities were practiced in Ras Al Khaimah, Fujairah, Al Ain and Liwa Oasis long ago. Since 1971 and the emergence of the federation of the United Arab Emirates, agriculture has gained considerable government support, and farms all over the country have been provided with irrigation networks supporting modern irrigation technologies, with a 50% government subsidy. At the present, emphasis is on the wide application of advanced irrigation techniques instead of the old conventional flood-irrigation method. The MOEW (2015) statistics illustrated that sprinkler, drip and bubbler irrigation technologies have increased from 32% in 1999 to

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Table 21.5  Mainland area (in hectare = 10,000 m2) and number of farms per emirate in 2003 in the UAE Emirate Ajman Umm Al Quwain Fujairah Ras Al Khaimah Sharjah Dubai Abu Dhabi Total

Mainland area (km2) 259.0 777.0 1166 1684 2590 3885 67,340 77,700

Percent 0.30 1.00 1.50 2.20 3.30 5.00 86.7 100.0

Number of farms 691.0 343.0 4346 4465 4392 1326 22,985 38,548

Area (Hectare∗) 2104 1693 5324 13,571 13,275 6176 218,590 260,732

After FAO (2008) ∗ Hectare = 0.01 km2

Table 21.6  Numbers of farms and their total areas in the emirates in 2005 No. 1 2 3 4 5

Emirate Abu Dhabi Dubai Sharjah Ajman Umm Al Quwain 6 Ras Al Khaimah 7 Fujairah Total

Number of farms 24,297 1281 3801 680.0 403.0

Total area (Hectare) 2,328,269 56,712 115,395 40,819 15,748

Cultivated area (Hectare) 2,103,195 28,432 75,522 9901 7219

Uncultivated area (Hectare) 225,074 28,280 39,873 30,918 8529

4489

122,332

71,635

50,697

4161 39,112

48,396 2,727,671

39,229 2,335,133

9167 392,538

91% of irrigated land in 2011. The government support of agriculture boosted the sector and caused a remarkable increase in the number of farms—from 4000 farms in 1971 to 35,704 farms in 2011 (Figs. 21.2 and 21.3)—with an area of 105,257 hectares (1053 km2). The MOEW (2015) highlighted the UAE efforts towards reaching high-quality agricultural production. These efforts led to the have establishment of an agricultural manufacturing facility of three animal-raising farms and 54 organic plant-­ producing farms. The area producing organic products in the UAE increased from 218 hectares in 2007 to 3920 hectares by the end of 2013 (Fig. 21.4). The MOEW’s (2015) State of Environment Report summarized the main challenges facing the agricultural sector as: the scarcity of appropriate irrigation water, high production costs, agricultural pests, post-harvest losses and increasing soil salinity. The UAE depends on groundwater for crop irrigation. The total dissolved salts (TDS) of irrigation water vary between 400 and 4500 mg/L and could be higher in some areas. The cultivated area has increased during the past years to reach 245,000

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Fig. 21.2  Evolution of the number of farms and modern irrigation techniques during the period 1977–1993

Fig. 21.3  Evolution of the number of farms and modern irrigation techniques during the period 1998–2002

Fig. 21.4  Evolution of the organic production farms during the period 2007–2013. (MOEW 2015)

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hectares (2450  km2), but the shortage of irrigation water is a major obstacle to increasing farmland. The country is now suffering from a growing shortage of the irrigation water drawn mainly from groundwater. The mean annual rainfall was 120  mm during the period 1974–2003, dropped to 83  mm during the period 2003–2015, due to climate change, despite the growing demand for groundwater and limited annual recharge. This has led to disruption of the water balance, lowering of groundwater levels and increasing TDS in many areas, especially during dry years. The UAE has made great efforts for the conservation, development and rational use of groundwater because it accounts for more than 70% of the agricultural water used. The UAE has taken serious steps in cooperation with global experts during the period 1976–1981 in order to choose the best irrigation technologies and compare the various irrigation methods used in other countries of similar climate conditions. After years of continuing research into modern irrigation methods for soil and climate conditions in the country, it was found that the drip-irrigation method is the most suitable for the irrigation of vegetable crops and forest trees. The sprinklerirrigation method is the best for the irrigation of forage crops, and the bubble-­ irrigation method is the best for date palms, fruit and ornamental trees. The UAE provides support for farmers through dissemination of modern irrigation systems. In this regard, the country has achieved considerable success in reducing agricultural land irrigated by traditional methods—from 80% in 1993 to 17% in 2001 (Figs. 21.5 and 21.6). In 2015, modern irrigation techniques covered over 90% of farmlands in the country (MOEW 2015). The traditional irrigation methods are no longer used except in some old farms and for irrigation of some fodder crops. Ongoing research continues on techniques to increase the efficiency of modern irrigation systems and to conserve irrigation water used in agriculture.

Fig. 21.5  Evolution of the green lands and areas of forests (in Hectare), during the period 1980–1992

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Fig. 21.6  Evolution of the green lands and areas of forests during the period 1998–2002

21.3  Sources of Irrigation Water Groundwater is still the main source of irrigation water in the UAE. Small and unreliable portions of irrigation water are obtained from irregular and highly variable seasonal foods, especially in the northern and eastern parts of the country. Aflaj systems and water from some permanent springs and several temporary base flows are also used for irrigating (Rizk 1998; Rizk and El-Etr 1997). Tertiary treated wastewater is used for irrigation of public parks, landscapes and green spaces, while desalinated water is used for irrigation in some instances at some locations in Abu Dhabi Emirate (Alsharhan et al. 2001). Groundwater and seasonal flood water are the two main sources of water used for irrigation. Both sources exhibit large fluctuations in quality and quantity depending on the widely variable annual rainfall and flooding events. The large development of agricultural areas during the past five decades has resulted in the sharp decline in groundwater levels and the increase in salinity of irrigation water in almost all agricultural provinces in the UAE. Al Asam and Sattar (2005) addressed agricultural development in desert regions and expressed its large dependence on groundwater resources. The establishment of the state in the 1970s boosted the agricultural sector, which witnessed great expansion at the expense on the groundwater reserves, which were subsequently severely depleted. This depletion is clearly manifested in the marked drop in groundwater levels (Figs. 16.1 and 16.2). The documented decline in groundwater levels ranged from 3 to 4 m per year (Fig. 16.1). Limited groundwater recharge takes place during exceptionally high flooding seasons. The estimated annual groundwater recharge varies between 120 and 150 Mm3, while groundwater abstraction in 2005, for example, reached about 4000 Mm3. In the UAE, rainfall varies in time and space. It also exhibits wide fluctuation from year to year. As a result, flood events also vary in time, space and magnitude,

21.4 Irrigation Methods

639

depending on rainfall duration and intensity. Starting in the 1980s, the UAE has built several dams and breakers in main wadis of the northern and eastern mountain ranges to utilize runoff water for irrigation and groundwater recharge. In addition to an unknown volume of groundwater recharge, dam reservoirs in the UAE have a storage capacity of about 112 Mm3. Lately, aflaj water in the UAE is only used for irrigation purposes. Despite its limited quantity (about 9.0–31.2 Mm3 per year), aflaj water has good quality and is seasonally recharged from rains falling on their recharge areas. Groundwater mining in the UAE during the past four decades has caused serious water quality and quantity problems and forced the government to rely on alternative water sources: mainly desalinated water and treated wastewater. The Ministry of Climate Change and Environment (MOCCAE), in cooperation with the Environment Agency of Abu Dhabi (EAD), ICBA and other related authorities, is looking for salt-tolerant plant species of economic value to use seawater as the irrigation water. FAO (2007) pointed out that the MOCCAE, in cooperation with the ICBA, is assessing the potential use of seawater for production of date palms.

21.4  Irrigation Methods The irrigation methods in the UAE evolved from conventional flood irrigation to modern sprinkler, drip and bubbler irrigation technologies. The MOEW (2015) indicated that modern irrigation techniques increased from 32% in 1999 to 91% of the irrigated area in 2011. Experiments carried out on drip-, bubbler- and sprinkler-­ irrigation methods at the Humraniyah Agricultural Research Station (HARS) indicated that the application of these technologies could save 80% of water used for irrigation. These technologies also save 70–80% of workers’ labor. Methods of date- palm irrigation depend on soil type, irrigation water quality, topography, climate conditions, the labor force and the age of the date palms.

21.4.1  Conventional Irrigation Methods The traditional method of irrigation of date palms comprises a separate circular, rectangular or square basin for each palm, which can reach an area of 4 m2. The irrigation water is kept inside the basin by an earthen barriers or bunds built around the basin (Aboodi and Al-Shakir 2004). Individual palm basins are fed by irrigation water moving through an earthen or cement-lined conduit to the main cement water storage tank. The farm topography affects this irrigation method and can lower its efficiency to 50–60%. This irrigation method is used for mature date-palm trees of on long-standing farms.

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21.4.2  Advanced Irrigation Methods The UAE government supports farmers to use modern irrigation techniques and provides modern irrigation systems, covering 50% of the cost. This government support has the greatest impact on the provision of large quantities of the groundwater resources used in agriculture. Adoption of modern irrigation systems has saved up to 60% of the amount of water used in modern irrigation, compared with traditional methods (Al Asam 1994, 1996). In addition to the great reduction in the amount of water used in irrigation, the modern irrigation techniques have contributed to the increased production of agricultural crops. For these reasons, modern irrigation techniques that were virtually nonexistent in the UAE before 1980 supplied 40,455 hectares in 1995 of the total planted area of about 65,557 hectares, meaning that 62% of agricultural land in the UAE was then irrigated with modern irrigation methods. The agricultural land in 2005 totaled 245,000 hectares (Starbuck and Tamayo 2005), 83% of which was irrigated with modern irrigation methods (Table 21.7). Table 21.8 shows the quantity and area of irrigated farms using modern irrigation methods versus the area irrigated by conventional methods in 2005. Table 21.9 shows areas suitable for cultivation and utilized areas in crop production in the UAE, based on records of the former Ministry of Environment and Water (Figs. 21.5 and 21.6) Figure 21.7 illustrates that Abu Dhabi accounts for the largest number of farms in the UAE. Abu Dhabi Emirate has 24,297 farms of a total number of 39,112 farms, or 62%, while the remaining farms are distributed among the rest of the UAE emirates. Figure 21.8 shows the proportion of areas of cropland to green areas in various emirates. 21.4.2.1  Drip Irrigation In the drip-irrigation technique, water reaches the plant in calculated amounts and slowly from of individual points or connected through small parts called drippers. The drippers are either connected as part of irrigation pipe or as a separate part mounted on the tube. This method is usually used for the irrigation of vegetable crops, ornamental trees and forests. Drip irrigation has several advantages that ensure optimal water use and reduced water loss through evaporation, surface ­runoff, infiltration and leakage, as often happens in traditional irrigation methods. Table 21.7  Areas suitable for crop production in the UAE (Hectare = 10,000 m2), based on data from the Ministry of Environment and Water (after the World Bank 2005) Category Number of Farms Cultivable area Crop production area

Year 1998 25,212 111,365 93,333

1999 28,369 235,948 214,422

2000 35,584 273,332 244,613

2001 37,550 269,059 241,423

2002 38,209 270,941 242,422

21.4 Irrigation Methods

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Table 21.8  Quantities and areas of farms irrigated by modern irrigation techniques versus the quantities and areas of farms irrigated by traditional methods in 2005 (after the World Bank 2005) Abu Emirate Dhabi No. of farms 21,740 Drip 1,571,854 Sprinkler 23,117 Fountain 44,2111 Others 3734.0 Modern 2,040,816 irrigation Flood 62,380 irrigation 2,103,196 Total irrigated area

Umm Al Dubai Sharjah Ajman Quwain 892.0 1746 262.0 226.0 963.0 7677 841.0 919.0 4730 7896 648.0 1023 5437 24,503 4151 2785 11,164 8241 650.0 1043 22,294 48,317 6291 5770

Ras Al Khaimah 1125 12,679 11,087 19,851 6990 50,607

Fujairah 369.0 1012 2639 10,331 342.00 14,325

Total 26,360.00 1,595,945 51,139.00 509,169.0 32,165.00 2,188,418

6139

27,206 3610

1449

21,027

24,905

146,716.0

28,433 75,523 9901

7219

71,634

39,230

2,335,134

∗Area are in Donum (Donum = 1000 m2) Table 21.9  The areas and quantities of farms applying localized and sprinkler irrigation in the UAE in 2003 (after FAO 2008) Region Abu Dhabi Central Northern Eastern Total

Farm Numbers 20,227 2015.0 842.00 337.00 23,421

Area Sprinkler 18,046 1424 1724 160.0 21,354

Bubbler 19,939 2231 1110 774.0 24,053

Drip 145,335 1444.0 1651.0 197.00 148,627

Other 3499 821 1061 0.00 5380

Total 186,818 5919.0 5546.0 1131.0 199,414

Drip- irrigation reduces the growth of weeds around the plants due to the small wetted surface areas, which are limited to the plant and the immediately surrounding area only (Photo 21.1). Drip irrigation can be used in highly sloped areas and irregular terrains. It also saves energy and much labor. Drip irrigation is not affected by wind and can operate during the night or day. The system can also reduce the risk of pests and plant diseases that arise on wet leaves because the vegetation cover always remains dry. The blockage of drippers is the main problem of a drip-irrigation system. This problem is directly related to the quality of irrigation water. The blockage results from the presence of organic or inorganic salts subject to deposition or biomaterials in irrigation water. Drippers blockage can be avoided through periodic inspection of the drip system to detect any problems in the performance of the drippers as a result of leaky pipes or the failure of equipment or devices attached to the system. Appropriate filters can be installed because irrigation water usually contains many impurities that must be removed before reaching the drippers and clogging the vents causing irregular distribution of water to plants. Pipe networks can be washed by

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Fig. 21.7  Comparison of the number of farms in various emirates in the UAE

Fig. 21.8  Evolution of the number of farms and modern irrigation techniques during the period 1998–2002

opening the ends of the main pipes. Chemical treatment of irrigation water involves the use of sulphuric or hydrochloric acids to minimize chemical deposition of salts. Phosphoric acid can also be used to treat water because this source of fertilization and chlorination is one of the main ways to reduce bacterial activity.

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Photo 21.1  Drip-irrigation technique in greenhouses of protected agriculture in the UAE saves water and increases productivity. (From Al Asam 1996)

21.4.2.2  Sprinkler Irrigation Sprinkler irrigation is used in dense field crops, fodder and green areas in gardens and with vegetables that are comparable distances and irrigated by low-salinity water. Sprinkler-irrigation technology delivers irrigation water to the plants in a way very similar to natural rain by its being pumped through a piping system. The pump supply system, sprinklers and operating conditions must be designed to deliver a uniform application of water. The droplets size depends on the sprinkler’s nozzles and the operating pressure. Irrigation methods can be divided into three groups: fixed sprinkler systems, where pipelines are fixed or buried under the soil and sprinklers that are installed on the pipes above the surface of the soil. The irrigation process is controlled by opening and closing valves per plot, and moving to the next plot until all the plots have been irrigated. This type of sprinkler irrigation is the most common in the UAE. The second type includes mobile systems that have parts along a main and branch lines. The lines of sprinklers can be transferred to water the other plot of cultivated area. The third type is the systems that move mechanically on wheels in lines or in circles, such as the pivot irrigation, which extend as moving arms, irrigating large areas. One of the advantages of sprinkler irrigation is that it functions in difficult terrain. It also does not require particular attention to a water filter because of the large drop size and the sprinkler’s slot machine does not get clogged easily. This system works as a demulcent for the heat in the field, creating a favorable climate for the growth of the crop. To ensure the success of sprinkler systems, its specifications, such as diameter of the sprinkler, wetness circle and elevation angle have to be carefully calculated. The wind speed and direction and proper pressure suitable for the crop type, soil characteristics, discharge and the distance between sprinklers are important parameters in this irrigation technique (Photo 21.2).

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Photo 21.2  Sprinkler-irrigation technique is used in dense field crops, fodder and green areas irrigated by low-salinity water

Photo 21.3  Bubbles-irrigation technique is best for the irrigation of date palms, fruit and ornamental trees because it irrigates a large group of trees simultaneously and in a short period of time

21.4.2.3  Bubbles Irrigation Bubbles irrigation is an improved pond irrigation system, in which water bubbles down and is distributed in the tree sink. This system of modern irrigation has proven to be the best for the irrigation of date palms, fruit and ornamental trees. The advantage of this system is irrigating of a large group of trees simultaneously and within a short period of time. It can use brackish water to wash away salts in the root zone and to help spread the roots over the sink to the depths in the soil. The success of this system depends on thorough maintenance at specific intervals, which extends the life of the system, improves performance, lowers operating costs and reduces the chances of sudden cessation, which can affect irrigation scheduling. The full maintenance includes monitoring pumping units, electric motors, filtration equipment, fertilization and water gauges, valves and control instrumentation and piping drippers, bubbles and sprinklers (Photo 21.3).

21.5 Protected Agriculture

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21.5  Protected Agriculture Protected agriculture means production of crops in greenhouses or plastic houses when these crops are difficult to grow in open fields. The number of such structures rose from 1678 (covering an area of 56 hectares) in 1986 to 3960 (covering an area of 156 hectares) in 1993. Although crop production under protected environmental conditions is  relatively more expensive, it is still economically viable, given the abundant yield, product quality and resultant reduction of water used for irrigation and fertilizers. Abu Dhabi Emirate, particularly in the Al Ain area, witnessed a sharp increase in greenhouses in 2015, related to the growing role in protected agriculture in fostering agricultural production (Fig. 21.9). The spread of protected agriculture in greenhouses depends on a group of factors, including the lower amount of water needed for irrigation. In many regions where agriculture is in greenhouses, there is a large saving in water used for irrigation. The production of agriculture in greenhouses is higher when compared with production under conditions of traditional agriculture. It is possible to produce vegetables in greenhouses, even in rocky or salty soil, including transported soil. Agriculture in greenhouses extends the growing season for some vegetables. In 2005, the number of greenhouses reached 9954, covering a total area of 2760 acres (Table 21.10 and Fig. 21.10).

Fig. 21.9  Evolution of the number of greenhouses in Abu Dhabi Emirate during the period 2010– 2015. (After SCAD 2016)

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Table 21.10  Numbers and areas (Dunam = 1000 m2) of greenhouses used in protected agriculture in the United Arab Emirates in 2005 No. 1 2 3 4 5 6 7 Total

Emirate Abu Dhabi Dubai Sharjah Ajman Umm Al Quwain Ras Al Khaimah Fujairah

Number of greenhouses 4809 92.00 772.0 1043 45.00 2299 894.0 9954

Area (Dunam) 1517 49.00 344.0 87.00 14.00 478.0 271.0 2760

Fig. 21.10  Distribution, numbers and areas (Dunam) of greenhouses in the UAE in 2005

21.6  Biosaline Agriculture The Food and Agriculture Organization (FAO) estimated the need for 200-million hectares of agricultural land for the production of various crops (Sattar 2003). The availability of this area is only 93 million hectares that can be used in agricultural expansion. Although this area is less than half the space required, the bulk of it is now occupied by forests, which must be preserved for maintaining the environmental balance and the Earth’s climate. Saline agriculture through the use of seawater for irrigation is a critical idea. The oceans and seas store 97% of Earth’s water, while the desert covers 43% of the Earth’s surface. If this type of agriculture succeeds, food can then be produced without compromising forest lands or depleting freshwater aquifers. To be meaningful and economically feasible, biosaline agriculture has to produce useful crops with a return greater than the costs of setting up the project infrastructure. There should be no damage to the environment and agricultural development has to be sustained and sustainable.

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Fig. 21.11  Relationship of crop productivity (%) and electrical conductivity (EC in mS/cm) of irrigation water

But, biosaline agriculture remains in the research and experimental stages because, until now, there are no kinds of traditional crops that could produce acceptable economic yields under conditions of seawater irrigation in the desert climate prevailing in the UAE. The ICBA is spending great research efforts in the area of biosaline agriculture. Researchers in the center are trying to develop varieties of traditional crops, such as wheat and barley, which have gained resistance to salinity by using genetic ­engineering methods. Through these methods, salt-tolerant genes are inserted into the seeds of several crops, but so far those efforts have not resulted in production of strains that can tolerate seawater irrigation over the long term. The date palm trees, the most salt-tolerant crop, tolerate salinity of less than 5000  mg/L, while the salinity of seawater varies between 35,000 and 40,000 mg/L. Seawater is also rich in sodium, which is the most damaging element to plants and soil. The crop productivity is expected to decrease with increasing TDS in irrigation water (Fig. 21.11). Some wild plants called halophytes are salt tolerant and can be used in producing medical materials, oils or perfumes or even as food for human. For several years, researchers have been collecting and classifying halophytes worldwide, depending on the degree of salinity they tolerate, as well as their food content. There are between 2000 and 3000 species of halophytes, including herbs, shrubs or trees that are plants that grow in salt water in coastal areas of the UAE. Biosaline agriculture is performed in silty, sandy land covered with sand dunes, because it is important to have soil of good natural drainage. Irrigation using seawater can cause damage to any freshwater aquifer. Therefore, it is important to conduct detailed hydrogeologic studies of aquifer systems in the areas selected for irrigation with seawater, to preserve the groundwater and prevent contamination by saline agricultural drainage water.

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The soil leaching that prevents salt accumulation in the roots zone of plants is one of the most important factors for success when growing salt-tolerant plants. The precision in the choice of irrigation periods is a key factor for achieving high yields of salt-resistant plants using seawater. Irrigation scheduling must be from 1 to 10 days, depending on soil and climate conditions. In the case of dunes, daily regular irrigation is required during the summer, while silty soil can retain sufficient irrigation water if irrigated every 10 days in the winter. The ongoing research and development programs of the ICBA were made possible through the UAE, which conducted field experiments and conducted scientific research studies to develop and implement advanced irrigation techniques for the development of modern agricultural practices in this dry region. The following sections recount some of the efforts of the ICBA.

21.6.1  Water Conservation Large volumes of brackish and saline groundwater are available inland and in coastal areas, which can be used for irrigation of salt-tolerant crops. However, this water is not suitable for irrigation of vegetables, which are mainly produced in greenhouses. Instead, small reverse osmosis (RO) desalination plants are gaining popularity among farmers, who use their water to irrigate date palms and vegetables in greenhouses and to produce water for drinking and other domestic purposes (ICBA 2010). The use of RO desalination technology requires proper brine disposal practices in order to minimize groundwater pollution. Different irrigation techniques are applied for different crop types. Micro-­ sprinklers are applied for vegetables, surface-drip irrigation is used to vegetables both in fields and greenhouses and bubblers are applied for fruit trees and date palms. Brackish groundwater, salinity varying from 4 to 37  mS/cm, was used as feedwater, and the capacity of plants varied between 28 and 325 m3/day. The reject brine varied between 69 and 99%, and the produced water contained from 30 to 87%. The large variation in performance of desalination plants depends on a parallel variation in membrane characteristics, the pressure applied and feedwater salinity. The chemistry of brine showed elevated levels of nitrate ion (NO3−) and low contents of trace metals. The methods of brine disposal include surface disposal, which is the most commonly practiced, followed by well-injection wells. Surface disposal methods could be replaced by environmental friendly methods such as properly-designed evaporation ponds and biosaline agriculture.

21.6 Biosaline Agriculture

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21.6.2  Water Reuse In 2010, ICBA cooperated with international experts in water resources from various countries to develop strategic plans for capturing, recycling and reusing treated municipal and industrial wastewater in the Emirate of Abu Dhabi. Treated wastewater is a reliable, renewable water source when properly treated, stored and transferred for usage in agriculture, landscaping and forests’ irrigation. In industry, recycled water is used in processing, washing, cooling, groundwater recharge and control of salt-water intrusion in coastal areas.

21.6.3  Water Data The USAID has supported the ICBA to establish an advanced NENA data-­ assimilation model. A link has been initiated in order to download satellite images, which were used in the modeling studies related to water, energy and agriculture. Field-data agriculture, groundwater, energy and surface water required for calibration and verification of the model were collected by ICBA.

21.6.4  Irrigation Efficiency The current irrigation practices in the country are based on extensive water use rather than water-demand management. This practice, which provides considerable social and economic support to farmers, has been encouraged by large government subsidies. Its development over the last 20 years has been largely unplanned and has not taken into consideration the suitability of soil and water resources (ICBA 2010). Therefore, ICBA called for using brackish and saline groundwater and treated wastewater for irrigation of salt-tolerant crops and water saving measures through irrigation-water management and application techniques.

21.6.5  Water Storage Aquifer storage and recovery (ASR) techniques are widely practiced around the world. The US and Australia incorporate treated wastewater in their plans for integrated water-resource management. It is common now to store treated sewage water during the winter or when less irrigation water is needed. This water is recovered

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21  Advanced Agricultural Technologies

during the summer when there is a high demand for irrigation water. ICBA participated in testing the use of treated wastewater to grow wheat with drip- and furrow-­ irrigation methods and to increase irrigation efficiency and productivity of the treated wastewater in the ASR scheme. The ASR method can be widely used in the UAE to store desalinated water produced by reverse osmosis (RO) technology, either for removing salts of for water softening. Practical experience has proved that combining desalination and the ASR technology is economically feasible.

21.6.6  Seawater Use in Biofuel Masdar Institute of Science and Technology (MIST), along with several companies, is keen to evaluate the potential of growing Salicornia with seawater for use as a biofuel and the maintenance of global CO2 equilibrium. A halophyte that grows in salty water, Salicornia has seeds which are an abundant source of biofuel. Shahin and Salem (2015) studied the current and future water requirements of the date palm (Phoenix dactylifera), which is a very essential traditional tree in the UAE.  This tree is considered one of the main sources of food in the country. However, the scarcity of water resources, depletion of aquifer systems and sharp growth of the population create a real challenge to provide the irrigation water needed for such an economically important tree. Results show that the total volume of treated sewage water (578 Mm3/year) can hardly meet the irrigation requirements of date palm trees in the country (640 Mm3/year) by the year 2030 (Fig. 21.12).

Fig. 21.12  Growth of agriculture water demand in the UAE for the period 1990–2010. (After Shahin and Salem 2015)

21.9 Agriculture Policies

651

21.7  Aquaculture and Hydroponics Al Qaydi (2016) believes that combining fish farming with hydroponics could increase agricultural production and conserve water in the UAE, where the fish fertilize water that nurtures the plants. Other projects in Beniyas (Abu Dhabi), Al Ain (Abu Dhabi) and Khor Fakkan (Sharjah) saved water at rates of 60–70%, 75% and 50–80%, respectively.

21.8  Agriculture and the Environment The UAE increased the area covered by forest from 2450 km2 in 1990 to 3226 km2 in 2014, to minimize the impacts of climate change, protect the soil and repair sand dunes (Fig. 21.13).

21.9  Agriculture Policies Cooperation with international organizations and research efforts has focused on identification of the most appropriate irrigation methods to the prevailing climate and soil conditions in the UAE. FAO (2008) referred to a pilot farming project in the UAE that saved 60% of irrigation water when using modern irrigation technology in 1983 in the UAE. The regulatory framework of the agricultural sector, which is the main water consumer, was enhanced by the Ministry of Climate Change and Environment

Fig. 21.13  Evolution of the area of forest plantation in the United Arab Emirates during the period 1990–2015. (After the World Bank 2015)

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21  Advanced Agricultural Technologies

(MOCCAE), which continues to investigate and manage groundwater resources, soil salinization and quality, construction of recharge dam, irrigation-network operation, and maintenance through the promotion of modern irrigated agriculture and organic products. This green plot required the application of drip-fed irrigation, which is mainly generated from recycled water sources including desalination and treated wastewater (Bigas 2012). Szabo (2011) pointed to an agricultural policy being developed in Abu Dhabi Emirate to support local farmers, by focusing on the wide application of modern irrigation methods and the reuse of treated wastewater. Furthermore, Sharjah Emirate has recently issued a mandate to enforce the application of modern irrigation systems in all irrigated areas to preserve and conserve water. The UAE started construction the first groundwater-recharge dam in 1982. By 2015, more than 130 dams and breakers had been constructed for harvesting flashflood water in the northern and eastern mountain regions of the country. The groundwater-­recharge dams collected over 500 Mm3 of water until now. The total capacity of retention and detention dams in the country, which were built to divert flood water into the groundwater reservoirs, is 120 Mm3, in addition to increasing groundwater resources and protecting against the danger of flash floods in residential areas, farms and roads (FAO 2013). From a climate-change perspective, increasing food security requires addressing the water-energy-food (WEF) nexus, which is beyond the scope of this chapter. The application of modern irrigation technologies has definitely increased agricultural production and contributed to food security (Al Awar 2014).

References Aboodi AH, Al-Shakir SH (2004) Date production, marketing and date palm residual uses in United Arab Emirates. Date palm and dates residual uses conference, 6–8 June, Al-Madina, Saudi Arabia Al Asam MS (1994) Dams in the United Arab Emirates and their role in groundwater recharge. In: Proceedings of the second Gulf water conference, Manama, Bahrain, pp 203–218 Al Asam MS (1996) UAE water resources use in agriculture and conservation. In: International Desalination Association (IDA) conference of Desalination, Abu Dhabi, pp 625–637 Al Asam MS and Sattar HM (2005) Irrigation water management in the United Arab Emirates (policy and development). In: International conference on water, land and food security in the arid semi-arid regions 6–11 September, Mediterranean Agronomic Institute, Bari, Italy Al Attar A (2002) From middle east to middle west: managing freshwater shortages and regional water security. Role of biosaline agriculture in managing freshwater shortages and improving water security, World Food Prize, p 10 Al Awar MM (2014) Management of water resources in the UAE. Int J Environ Sustain 3(4):1–10 Al Qaydi S (2014) Small scale sustainable farming activities in the United Arab Emirates: the case of the East Coast of the UAE. In: The 2nd international conference on food and agricultural sciences IPCBEE, 77: 49–54 Al Qaydi S (2016) The status and prospects for agriculture in the United Arab Emirates (UAE) and their potential to contribute to food security. J Basic Appl Sci 12:155–163

References

653

Alsharhan AS, Rizk ZS, Nairn AEM, Bakhit DW, Alhajari SA (2001) Hydrogeology of an Arid region. The Arabian Gulf and adjoining areas. Elsevier Publishing Company, Amsterdam, p 331 Bazza M (2005) Policies for water management and food security under water-scarcity conditions: the case of GCC countries. In: Proceedings of the seventh Gulf water conference on water in the GCC—towards an integrated management, Kuwait 1: 719–733 Bigas H (2012) The global water crisis addressing an urgent security issue. United Nations University—Institute for Water, Environment and Health, Hamilton FAO (2008) United Arab Emirates. Irrigation in the Middle East region in figures – AQUASTAT Survey 2008, p 13 FAO (2013) Geo-referenced dams’ database—FAO’s Information System on Water and Agriculture. Retrieved March 6, 2013, from http://www.fao.org/nr/water/aquastat/dams/inde x.stm FAO (Food and Agriculture Organization) (2007) UAE country paper. In: Proceedings of the Workshop on Irrigation of Date Palm and Associated Crops, in collaboration with Faculty of Agriculture, Damascus University Damascus, Syrian Arab Republic, 27–30 May, pp 75–82 ICBA (International Center for Biosaline Agriculture) (2010) Enhancing food security through improved agricultural productivity. Annual report, Dubai, United Arab Emirates, p 36 MOEW (Ministry of Environment and Water) (2006) Wastewater management and reuse. Country profile MOEW (Ministry of Environment and Water) (2015) State of environment report. MOEW, UAE, p 36 National Bureau of Statistics (2015) Agricultural and environmental statistics. Available: http:// www.uaestatistics.gov.ae/EnglishHome/DepartmentsEnglish/tabid/104/SessionExpire. aspx?LanguageId=1 Peninsula. Summary Proceedings of a Regional Workshop, 29–31 May, 2004, Abu-Dhabi, UAE Rizk ZS (1998) Falajes of United Arab Emirates: Geological Settings and hydrogeological characteristics. Arabian J Sci Eng King Fahd Univ Petrol Miner Dhahran Saudi Arab 23(1C):3–25 Rizk ZS, El-Etr HA (1997) Hydrogeology and Hydrogeochemistry of some springs in the United Arab Emirates. Arab J Sci Eng King Fahd Univ Petrol Miner Dhahran, Saudi Arab 22(1C):95–111 Sattar HM (2003) Feasibility studies on the use of saline water for agricultural production in the Northern Agric. Region. MAF/ICBA Project, UAE SCAD (Statistics Center—Abu Dhabi) (2016) Agricultural statistics. Statistics Center  – Abu Dhabi, UAE, p 51 Shahin SM and Salem MA (2015) Review future concerns on irrigation requirements of date palm tree in United Arab Emirates (UAE): call for quick actions. In: Proceedings of the fifth international date palm conference, Al Ain, UAE, pp 255–262 Starbuck MJ and Tamayo J (2005) Monitoring vegetation change in Abu Dhabi Emirate from 1996 to 2000 and 2004 using Landsat satellite imagery. In: Proceedings of the seventh Gulf water conference on water in the GCC—towards an integrated management, Kuwait, 2: 817–831 Szabo S (2011) The water challenge in the UAE. Dubai Sch Gov Policy Brief 1(29):1–8 World Bank (2005) Report on evaluation of water sector in the GCC countries, Challenges facing water resources and water management and the way ahead. Arab Gulf Program for United Nations Development Organizations, p 113. (in Arabic) World Bank (2015). Worldbank.org/indicator/AG.LND.FRST.K2?|locations=AE

Part VIII

Modern Techniques in Water Investigations

This part addresses the modern techniques used in water-resources investigations such as remote sensing, geographic information systems, natural isotopes and numerical modeling. Modeling techniques involve collecting, processing, formulating and analyzing data and other information that are used, along with a number of software packages, in the representation of aquifer systems to optimize their management in the present and future according to various plans and strategies. Natural isotopes are widely used in water studies for identification of sources and ages of various water types, water renewability and recharge mechanisms, in addition to the calculation of groundwater-flow velocity, the possibility of determining mixing ratios of more than one water type and identification of water-pollution sources. Natural isotopes have been used to study the properties and sources of rainfall in the UAE, define areas for groundwater recharge, calculate ages and source(s) of groundwater, identify the source(s) that increase the concentration of total dissolved solids in groundwater and study water pollution caused by agricultural activities and oil industries. The remote-sensing techniques, as well as field work and laboratory analysis, are used for determination of the hydraulic properties of the sand dunes and interdune areas in the Al Ain Region of Abu Dhabi Emirate. Remote-sensing techniques are also used in groundwater surveys, determination of groundwater quality, recharge and discharge areas and presentation of fluctuations in groundwater levels. This part presents the results of treating and processing satellite images, image enhancement and extraction of information on the distribution of infiltration rates and uniformity coefficients in sand dunes and interdune areas and calculation of the amount of natural evaporation. The hydrologic studies using GIS techniques, in addition to geophysical data, hydrogeological measurements and the results of chemical analyses of groundwater samples, were used to assess the suitability of groundwater various uses in many drainage basins in the country. Measurements of natural isotopes in water samples from rain, springs, aflaj and groundwater throughout the UAE are intended to study the characteristics of winter and summer rainfall, identify sources and ages of groundwater in various aquifers,

656

VIII  Modern Techniques in Water Investigations

determine the source (sources) of increasing of groundwater salinity in the northern limestone aquifer of Wadi Al Bih basin in Ras Al Khaimah Emirate and identify the source of groundwater pollution in the Liwa Quaternary sand aquifer in the Bu Hasa oil field and Liwa agricultural area in the Western Region of the country. It is also used to assess the efficiency of some dams in groundwater recharge, identify groundwater flow directions and calculate groundwater-flow velocities in shallow and deep aquifers and determine the origin and age of groundwater. Various groundwater-flow and solute-transport packages, along with available geologic, hydrogeologic and hydrogeochemical data for water-well fields, were used for preparation of a numerical groundwater-flow model for the northern limestone aquifer in Wadi Al Bih basin at Ras Al Khaimah Emirate. The model covered the area between Wadi Al Bih main dam and Al Burayrat well field and simulated the aquifer’s predevelopment conditions and predicted hydraulic heads in the aquifer under various water-development scenarios. Results of other modeling studies on the eastern and western gravel aquifers in Fujairah and Al Ain areas are also presented.

Chapter 22

Application of Remote-Sensing Techniques for Water-Resources Investigations in the UAE

Abstract The remote-sensing (RS) technique, uniformity coefficient (Cu) and infiltration capacity (Ic) were used for the classification of Quaternary clastic sediments southwest of Al Ain City, eastern UAE. About 75 sand and gravel samples were collected from sand dunes and interdune areas for grain-size analysis and hydraulic-conductivity measurement. Measurements of infiltration rates (Ir) were carried out in 27 sites during sampling with the use of a double ring infiltrometer. The interdune areas were classified into four classes: standing water (C1), >50% moisture (C2), 5–25% moisture (C3) and 50% soil moisture (C2), soil moisture 50–25% (C3) and soil moisture 1.5

C2

Soil Moisture > 50%

C6

Cu = 1.4 : 1.5

C3

Soil Moisture = 25 : 50%

C7

Cu < 1.4

C4

Soil Moisture < 25%

Fig. 22.6  Classification of sand-dune areas (C5, C6 and C7), based on uniformity coefficient (Cu), and interdune areas (C1, C2, C3 and C4), based on soil moisture content. (After Rizk et al. 1998a, b)

666

22  Application of Remote-Sensing Techniques for Water-Resources Investigations…

Table 22.1  Calculation of dune-covered areas and interdune areas around Al Ain city, based on field survey and satellite images Class C1 C2 C3 C4 C5 C6 C7 Total

Area (km2) 0.50 2.60 64.20 239.20 469.10 1044.9 948.20 2769

Area (%) 0.02 0.09 2.32 8.64 16.94 37.74 34.25 100

Number of pixels 539 2872 71,344 265,737 521,174 1,160,973 1,053,591 3,076,230

Table 22.2  Calculation of evaporation rate (m3/year) from dune and interdune areas C1 and C2, west of Al Ain Region of Abu Dhabi Emirate, based on supervised classification Parameter Area Average daily evaporation Total daily evaporation Total annual evaporation

Class C1 0.50 9.75 4875 17,832,000

Class C2 2.5 5.0 12,500 4,569,000

Units km2 mm/day m3/day m3/year

22.4.4  Calculation of Natural Evaporation The total volume of annual evaporation was accurately calculated for the areas C1 (standing surface water) and C2 (shallow water table), from the data of the various classes listed in Table 22.1. Based on data shown in Tables 22.1 and 22.2, the amount of evaporation from surface water (C1) and shallow groundwater (C2) in the Al Ain area, eastern Region of Abu Dhabi Emirate, was calculated as 6.35 Mm3/year. The annual recharge for groundwater in the Al Ain area was estimated from the climatic water balance as 4 Mm3 (Rizk et al. 1998a, b), indicating that the annual evaporation is higher than the annual groundwater recharge, within the study area.

References Al Muhairi A, Ghedira H, Al-Ahmad H, Dawood A (2011) Using remote sensing satellites for water quality monitoring in the UAE, IEEE GCC Conference and Exhibition (GCC), Dubai, pp 67–68 Bedendo DJ (1990) Use of geographic information system and data processing in the assessment of soil degradation. M. Sc. Thesis, ITC – Enschede, Netherlands Elmahdy SI, Mohamed MM (2015) Groundwater of Abu Dhabi Emirate: a regional assessment by means of remote sensing and geographic information system. Arab J Geosci 8:11279–11292 Friedman SZ (1986) Mapping urbanized area expansion through digital image processing of Landsat and conventional data. Publication 79–117. Jet Propulsion Laboratory, Pasadena

References

667

Garamoon HK (1996) Hydrogeological and geomorphological studies on the Abu Dhabi–Al Ain– Dubai rectangle, United Arab Emirates. Ph. D. Thesis, Ain Shams University, Cairo, Egypt, p 277 Howari FM, Sherif MM, Singh VP, Al Asam MS (2009) Application of GIS and remote sensing techniques in identification, assessment and development of groundwater resources. In: Chapter 1 Application of GIS and remote sensing techniques, pp  1–25. https://doi. org/10.1007/978-1-4020-5729-8-1 Lillesand TM, Kiefer WR (1987) Remote sensing and image interpretation. Wiley, Hoboken, p 721 Moik H (1980) Digital processing of remotely sensed images. NASA Sp. Publ. no. 43, Washington, DC Pettyjohn W (1979) Ground water and satellites – an overview\introduction. In: Satellite hydrology. American Water Resources Association, Middleburg, pp 385–386 Pratt WK (1978) Digital image processing. Wiley, New York, p 750 Rizk ZS, Garamoon HK, El-Etr HA (1998a) Application of remote sensing techniques to a hydrogeological investigation of sand dunes southwest of Al Ain city, United Arab Emirates. Egypt J Remote Sens Space Sci 1(1):369–390 Rizk ZS, Garamoon HK, El-Etr AA (1998b) Hydraulic properties of dune and interdune areas around Al-Ain, United Arab Emirates. In: Alsharhan, Glennie, Whittle, Kendall (eds) Proceedings of the international conference on quaternary deserts and climatic change. Balkema, Rotterdam, pp 455–467 Sabins FF (1987) Remote sensing: principles and interpretation. W. H. Freeman, New York, p 449

Chapter 23

Application of GIS Techniques for Water Resources Investigations in the UAE

Abstract Rizk and Alsharhan (Geographic information system modeling of groundwater potentiality in the northeastern part of the United Arab Emirates. In: Alsharhan AS, Wood WW, Goude AS, Fowler A, Abdellatif EM (eds) Desertification in the third millennium. Balkema, Lisse, pp  423–434, 2003a) reported that they used: “The ArcView GIS 3.2 package to construct a groundwater potentiality model for the Al Dhaid area, eastern UAE. Digitized data of geology, hydrogeology, water chemistry, water quality, geologic structures, drainage basins and soil classes were used along with the GIS package. Model results indicated that the eastern front of the modeled area has the highest groundwater potential and has to be treated as a protected zone. The output data were used for construction of zoned maps. Correlation of these maps was made to define areas with high groundwater potential for agriculture and domestic uses. The eastern front of the modeled area is located close to eastern mountain ranges, which is the main recharge area for groundwater in the UAE. This area also represents the intersection of the three major structural trends; Wadi Ham Line, Hatta zone and Dibba zone. These trends have a great influence on groundwater recharge and seem to control directions of groundwater flow. The groundwater in this is soft (TH 45 TDS >3000 mg/l SAR >10

GP-16 (East Dhain)

25° 15'

25° 25'

TDS>300 mg/l SAR>10

GP-03 (Manama) 25° 20'

55° 50'

B

5 km 55° 50'

55° 55'

56° 00'

Fig. 23.4  Showing soil classification map (a), groundwater suitability for irrigation map (b) and shallow groundwater resources map (c) in the Eastern Region of Sharjah Emirate in January 2000. (After Rizk and Alsharhan 2003a, b)

23.4.1  Model Construction This analytical model was constructed with the use of the ArcView 3.2 GIS software package. Rizk and Alsharhan (2003a) described: “The database used with the model includes digitized data and field data. The digitized data includes major geologic structures, drainage basins and soil classification maps, while the field data includes well locations, groundwater levels, concentration of chemical species and groundwater quality parameters”. Al Mulla (2001) indicated: “Data on total dissolved solids (TDS), total hardness, SAR (Fig. 23.4), depths to groundwater, were obtained from the Ministry of Climate Change and Environment. Collected data were stored in a database with a specific pattern (dbf 4 format)”. The data stored in the database were transformed into matrices, which were plotted according to  longitudes and latitudes of the soil classification map as a “base map”. Al Mulla (2001) described: “The unit dimension of the matrix was taken as 50 m × 50 m for each data point. Then, data were gathered and classified into matrices. Then, all maps were digitized according to the dimension of matrix data points. Correlation was made between different layers of the model, according the goals of the study. Finally, the model was constructed and different layers were correlated”.

678

23  Application of GIS Techniques for Water Resources Investigations in the UAE

Table 23.3  Input data of the analytical GIS model for Al Dhaid area, eastern Sharjah Emirate, and their applications Input Parameter Structural trends and drainage basins

Figure 23.5

Hydraulic head

23.6 (a) and (b) 23.7 (a)

Electrical conductivity (μS/cm) Total hardness (TH) Sodium adsorption ratio (SAR) Soil classification

23.7 (b) 23.7 (c) 23.8 (a)

Range –

Application Assessment of the impact of both parameters on the groundwater potentiality and recharge 95–230 m amsl Definition of recharge and discharge areas and directions of groundwater flow 705– Construction of iso-electrical conductivity 7500 mg/L contour and zoned maps 70–150 mg/L Preparation of iso-total hardness contour and zoned maps. 7–28 Construction is iso-SAR contour and zoned maps Suitable or Evaluation of soil types in terms of their unsuitable suitability or unsuitability for agriculture

23.4.2  Model Inputs Rizk and Alsharhan (2003a) summarized: “The input data for GIS analytical models for Al Dhaid area included hydraulic heads (m above mean sea level), total dissolved solids (TDS), total hardness (TH), sodium adsorption ratio (SAR), soil classification maps, geologic structures and major drainage lines (Table  23.3). The seven soil types in the UAE were re-grouped into two main types: soil suitable for agriculture and soil unsuitable of agriculture (Fig. 23.5)”.

23.4.3  Model Output Rizk and Alsharhan (2003a, b) mentioned that: “The model outputs were obtained by matching the related zones together, such as the depth to groundwater, fault zones and major drainage lines, total dissolved solids, total hardness, soil type and sodium adsorption ratio. The results of correlation between different parameters and the spatial distribution and variation are shown in Table 23.4. Results of the model simulation helped to define areas of priority for agricultural development and domestic and where water is suitable for domestic uses and drinking, according to the WHO (1984) standards. Al Mulla (2001), Rizk and Alsharhan (2003a, b) and Rizk and Garamoon (2006) concluded that: “The intersections of the main structural elements affecting the area are characterized by large secondary porosity and hydraulic conductivity, allowing accumulation of large amounts of groundwater in these intersections more than any other areas. It seems that the major structural zones determine, to a great extent, the directions and velocities of groundwater movement from the eastern mountains ranges towards Al Dhaid area.

23.4  GIS Model

679

25° 25'

55° 50'

55° 55'

56° 00'

A GP-03 (Manama)

25° 20'

25° 25'

25° 25'

25° 20'

25° 20'

55° 50'

55° 55'

56° 00'

25° 25'

B GP-03 (Manama)

GP-01 (Nasim)

25° 20'

GP-01 (Nasim)

Suitable for farming Unsuitable for farming High Surface water potential

GP-15 (South Dhain)

GP-17 (Borair)

High ground water potential Low ground water potential

GP-16 (East Dhain)

25° 15'

25° 15'

GP-16 (East Dhain)

25° 15'

GP-15 (South Dhain)

GP-14 (Siji)

25° 10'

25° 15'

25° 10'

25° 10'

25° 05'

25° 05'

GP-14 (Siji)

GP-17 (Borair)

25° 10'

Wells Fault 5 km

GP-06 (Hamdah)

GP-06 (Hamdah) 25° 05'

GP-07 (Mileiha)

25° 05'

GP-07 (Mileiha)

25° 00'

GP-11 (Sahlguf)

25° 00'

25° 00'

GP-11 (Sahlguf)

25° 00'

5 km

55° 50'

55° 55'

56° 00'

55° 50'

55° 55'

56° 00'

Fig. 23.5  Map showing areas suitable for agriculture (dotted areas on Figure a) and areas of high groundwater potentialities (dotted areas on Figure b) in eastern UAE. (After Rizk and Alsharhan 2003a) Table 23.4  Sample of a GIS model outputs for Al Dhaid area, eastern Sharjah Emirate and their spatial distribution Layers EC, fault zones, soil type Depth to water, EC, SAR and soil type

Ranges TDS < 1500 mg/L, intersections of structural zones and cultivable soil Depth