Rivers

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PUBLIC LIBRARY FORT WAYNE AND ALLEN COUNTY, IND

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RIVERS Irving

and Ruth Adler

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The John Day Company

— New

York

:

Books by Irving and Ruth Adler

NUMBERS OLD AND NEW

FROM TOPS TO ATOMS

THINGS THAT SPIN:

SHADOWS THE STORY OF A NAIL

WHY? RIVERS

Books by Irving Adler

FROM SPACE HOT AND COLD WEATHER IN YOUR LIFE

SEEING THE EARTH

DUST

THE TOOLS OF SCIENCE

THE SUN AND

ITS

FAMILY

MAN-MADE MOONS MONKEY-BUSINESS

HOAXES IN THE NAME OF SCIENCE

HOW

LIFE BEGAN

MAGIC HOUSE OF NUMBERS

THE STARS: STEPPING STONES INTO SPACE TOOLS IN YOUR LIFE FIRE IN

YOUR LIFE

TIME IN YOUR LIFE

THE SECRET OF LIGHT

© 1961 by Irving and Ruth Adler must not be reproany form without permission. Published by The John Day Company, 62 W^est 45th Street, New York 36, N.Y., and on the same day in Canada by Longmans Green & Company, Toronto. All rights reser\ed. This book, or parts thereof,

duced

in

Library of Congress Catalogue Card Number: 61-12714

Manufactured

in the

United States of America

U. SL 1254553 Contents Rivers

4

How Rivers Are Bom

6

Currents

8 9

Weathering

Wearing Away Mountains

10

VaUeys

12

The Grand Canyon

of the Colorado

14 16

Waterfalls

Water Gaps

18

Natural Bridges

20

Potholes

21

Treasure Hunting

22

Watersheds and Divides

24

Rivers That Are Pirates

26

The Lower River

28

Meandering

30

A River Changes Its Bed A River Changes Its Face

32

Taming Making

a

33

Wild River

34

36

Electricity

Rivers and Travel

38

Where People Live

.

40

*

Water Water

for Plants

.>

42

42

for People

Keeping Water Clean

43

Deltas

44

The Journey

Word

List

of a

Drop

of

Water

46 48

Rivers

^

This

is

a book about rivers.

Rivers are important for people. Rivers are important for plants

and animals,

Rivers help living things in

The water

that people

many

too.

ways.

and animals

drink often comes from rivers.

Some

of the fish that people eat are

taken from

rivers.

Many plants are used by people as food Growing

plants

need water. In some

places rivers help bring water to the land

where the plants grow. Rivers are natural roads. People use boats, barges

and

from one place

rafts

to carry things

to another along a river.

Rivers help people in other ways, too.

.^^

Rivers turn water wheels, making the machines in mills and factories work. Rivers

turn the machines that

make

electricity.

Rivers can help people enjoy their free time.

Some people

Many

boating.

most everyone

like to

people

go fishing or

like to

swim. Al-

likes to look at the pretty

scenery along a

When

rivers

flood their banks, they can carry

away

Rivers can also do harm.

people's

X

river.

homes and belongings.

we shall find out how rivers We shall see how rivers go down

In this book are born. to the sea

and what they do

they go there.

work

to

We

change

to the land as

shall see

how

people

rivers so that rivers will

always be helpful friends.

Pi^^ \

Ground

^

^ — ^

water \

i

\ ..

:

,

,

,

•:.::•>/

\

.

Spring Spring water flows downhill into the stream

^^V/ uiut I

.

Ground^:^^

'•^-:^^V:^^:'•:•^:-:^•:v^ntothe^sti^ai^t/^•^^

vr^.

Hoti; Rivers

Rivers are born high

up

Are Born

in the mountains,

from rain

and melted snow.

is

Much

of the rain that falls sinks into the earth. This

called

ground water. Some of

this

water flows out of

the ground again through openings in the rocks.

ground water comes out again

like this it

is

When

called a

The spring water then flows downhill and joins other springs to make streams. The streams also get ground water that goes into them right from the ground. Some rain flows downhill right away. The rain water spring.

flows along gullies

there is

is

and ditches

a lot of rain, the streams

no rain

for a long time,

When When there

into the streams.

become

full.

some streams dry

up.

Ground

water keeps other streams flowing even in dry weather. 6

In the wintertime,

snow piles up on the mountain tops. snow melts. Some of the melted

In the springtime the

snow sinks into the ground and becomes ground water. Some of the melted snow flows downhill into the streams right away. So, in the springtime when the snow melts, the streams are fuller than they are at other times.

They

are fuller in the spring, because a lot of rain

falls

then, too. In the mountains there are places that are

big bowls. Rain and melted snow

shaped

like

places,

making mountain

lakes.

When

fill

these

the lakes are

full,

the water begins to flow out of them. This water makes little

streams which go

down

the mountainside and join

other streams.

The mountain streams are the beginnings of rivers. The beginning of a river is called the upper river.

USOA Photograph

A mountain

lake

Currents If

there

is

snow on the ground, you may be able

coasting on a sled. hill is steep,

You

start at the

you coast down

not steep, you coast

down

it

it

more

you downhill. Gravity makes you ground

is

top of a

very quickly.

steep,

steep,

hill. If

If

the

go

the

hill is

slowly. Gravity pulls

travel faster

where the

steeper.

Gravity makes water flow downhill, too. is

to

If

the

hill

down it quickly. If the hill is not down it more slowly. But the sides of

water flows

water flows

a mountain are steep. So gravity makes the water in a

mountain stream flow

fast.

We

say that a mountain

stream has a fast current (CUR-rent).

U.S. Forest Service

A

fast flowing mountain stream

U.S. Geological Survey

Pile of smaller

rocks

made by weathering

Weathering Mountains are made up of

But they can be broken water and weather,

air.

it is

When

rock.

Rocks are very hard.

into smaller rocks

rocks are changed this

and

soil

way by

by the

called weathering.

Here are some ways weathering happens. If

you pour boiling water

into a cold glass, the glass

may break. If you fill a hot glass with ice water, the glass may break, too. The change from hot to cold, or from cold to hot, makes the glass crack.

Some

rocks

become

very hot during the daytime and very cold at night. The

change from hot

to cold, or

from cold

to hot,

makes the

rocks crack, too.

Rain and melted snow

becomes very

cold, the

When water freezes,

it

fill

the cracks in the rocks.

If it

water in these cracks freezes.

takes

up more

space. This

makes

the cracks bigger, and the rocks split into smaller rocks.

Wearing, Away Mountains

Flowing water slowly wears mountains away. ens the rocks and the

and

carries

them great

that weathering has

soil

distances. This

is

It loos-

made,

called erosion

(ee-ROW-zhun). As a stream flows down a

and sometimes ground

and

is

A

fast

It

sometimes

the ground

such a heavy load.

flows fast

where the

stream picks up rocks, stones

is

It

not so steep, the stream slows is

not strong enough to carry

drops some of the rocks and stones

has been carrying. But the stream

enough

it

flows fastest

flows along.

down. Then the stream

it

hill,

slows down.

steepest.

soil as it

Where

it

is still

sand and

moving

fast

soil. If

the ground

becomes steeper again, the stream can carry a

larger load

of rocks

to carry small bits of

and stones once more.

USDA Photograph

Land worn away by

rain water

U.S. Bureau of Reclamation

Footprints of a dried up stream

The beds

of

mountain streams and

rivers are

covered

with rocks. These rocks were carried along, and then

dropped, by the water. Some mountain streams dry up in the

summertime.

We

can

still

find their beds even

though the streams are no longer

have

left their footprints

there.

behind. There

is

and stones which the streams dropped

a

The streams trail

of rocks

as they flowed

along.

Streams drop

When more

many

stones at the foot of steep

hills.

they leave the mountains and travel slowly along

level ground, they also

they carry. 11

drop some of the

soil

that

U.S. Forest Service

The V-shaped

valley of the Colorado River

Valleys

The

sides of a

many httle hill in it

mountain are not smooth. They have

Mountain water

ditches.

these

little

ditches.

starts its trip

As the water flows downhill,

makes the ditches deeper and wears away

The

ditches begin to look like the letter V.

their sides.

Mountain

streams join with other mountain streams to river.

The V-shaped

which the

When

river flows,

the river

is

from the bottom of

is

it

picks

V-shaped

valley deeper. Rain water wears valley. This

makes the

a

other

V. This V,

called a valley (VAL-lee).

young,

its

make

come together with

ditches

V-shaped ditches to make an even bigger in

down-

soil

valley. This

away

valley wider. 12

up

and stones

makes the

the sides of the

When

the valley

is

wider,

its

the river

sides are not as steep. After a long time,

is

old, the valley

is

broad and

flat.

Then

when

it is

no

longer shaped like a V.

Some

river valleys

have been drowned by the

sea.

When this happens, sea water flows part way up the river valley.

So the river valley

is

hidden under sea water. This

Hudson River below the city of Albany, New York. That is why the Hudson River is salty all the way up to Albany, 150 miles away from the sea. The valley of the St. Lawrence River is drowned as far as Montreal. Delaware Bay and Chesapeake Bay are also drowned river valleys.

has happened to the

Chesapeake Bay before drowning

as

it

looks

now

U.S. Forest Service

The Grand Canyon

A and

valley its

called a

canyon (CAN-yun)

sides are very steep.

in places

not

is

of the Colorado

where the weather

is

deep

very dry. Then there

much rain water to wear away the

So, while the river

if it is

Canyons are usually found

makes the

is

sides of the valley.

valley deeper, the sides of

the valley stay steep.

The Colorado River is in the western part of the United States. It has made the largest and most beautiful canyon

in the world.

A

long time ago 14

this

land was

flat.

Many the

layers of different kinds of rock surfaces.

flat

make

its

Then

were underneath

the Colorado River began to

valley.

As the valley got deeper, the

different layers of rock

have different

began

to show. Different kinds of rock

colors.

So the sides of the valley have layers of

different colors.

The valley also kept Grand Canyon is ten

some places the the top and one mile deep.

Some

of the rock layers of the

softer than others.

They

harder layers. That

is

are

miles wide across

Grand Canyon

worn away

why the sides

many

getting wider. In

of the

are

faster than the

Grand Canyon

look like a big staircase.

The Colorado River at the

is

a

young

river. It is still at

bottom of the Canyon, making

The rock

its

work,

valley deeper.

layers look like a big staircase

Waterfalls

A

stream sometimes passes from a harder rock to a

wears away the softer rock more quickly.

softer rock. It

This makes the bed of the stream steeper and steeper.

Then

the water doesn't flow over the bed any more.

shoots over

The

its

bed

softer rock

in rapids.

underneath the river keeps wearing

away. Finally the river bottom

Then falls

of the Niagara River

water

is

so steep that

the water falls to the lower level. This

The shape still

It

a

cliff.

how

the

were made.

of the Niagara Falls

wears away the

it is

is

soft rock

is still

under the

the hard rock on top crumbles, too.

The Then

changing. river.

From time

to time

large pieces of rock at the top tumble into the water

below. So the

falls

Rapids

are slowly

moving upstream.

Waterfalls

The Niagara Falls are beautiful because they are so wide. The Falls are shared by the United States and Canada.

On the Canadian side they look like a horseshoe

a half mile long from end to end.

The

Falls are

about

160 feet high.

N.Y. State

The Niagara

Falls

Power Authority

Water Gaps

The rock

layers of the

Grand Canyon

of the Colorado

River are like layers of a layer cake. They are horizontal (

hah-rih-ZON-tull )

straight shelf.

,

or level. Sometimes rock layers are

up and down,

rivers cut their valleys

Some

may be

books standing on a library

vertical

soft, just like

easily than

soft layers.

where the

it

VUR-ti-kul )

Some

.

may be hard and some

the horizontal layers of the

river cuts

river valley gets

(

through vertical layers of rock.

of the vertical layers

Canyon. So the

more

like

These layers are

through the

Grand

soft vertical layers

cuts through the hard layers.

The

wider where the river has cut through

The

river valley stays

river has cut

steep part of the valley

Stream

How

through hard is

narrow and steep layers.

The narrow,

called a water gap.

Stream

a water gap

18

is

formed

Water

r

The Delaware River has made the states of Pennsylvania and

ware Water Gap

is

a water gap between

New

three miles long.

Jersey. Its

The Dela-

steep sides are

1,400 feet high.

Water gaps

are also called narrows.

U.S. Geological Survey

The Delaware Water Gap

Natural Bridges In Virginia there flows 200 feet

A just

is

a natural bridge of rock.

A

stream

below it. The stream has made the bridge.

long time ago there was a waterfall in the stream

below where the bridge

is

now. There was a large

crack in the rocky bed of the stream, above the waterfall.

Stream water flowed into the crack and came out again at the

bottom of the

falls.

The water made the crack larger and larger. Then became so large that all the water of the stream flowed through it. So a new waterfall was made

the crack

upstream.

The water

of this waterfall flowed

under the rock

where the old

falls

had been. The opening under the

rock of the old

falls

kept getting bigger and bigger. At

the same time, the Finally, all that

new waterfall

was

left of

kept moving upstream.

the old waterfall was a rocky

bridge over the stream that built

How

a natural bridge

is

it.

formed

U.S. Geological Survey

U.S. Forest Service

A

Natural Bridge of Virginia

pothole

Potholes

Sometimes a rock

will look as

though a big ice-cream

scoop has been at work making holes in holes are called potholes.

have been

at the

Water which

They

tell

These scoop-

us that the rock

bottom of a waterfall or under

falls

rapids hits the rocks

may

rapids.

from a great height or shoots down

below with a

lot of force.

bottom, the water turns and spins very carried

it.

fast.

The

At the stones

by the water spin around with the water. They

grind out the potholes in the rocks at the base of the or under the rapids. 21

falls

Treasure Hunting

Streams and rivers have

made

it

easier for miners to

find gold.

Gold

is

sometimes found in rock. But

it is

hard to get

The job of the gold miner is made easier when nature does some of the work for him. As rocks with gold in them are worn down by weathering, bits of gold break at there.

off

with

bits of rock.

Flowing water

carries these bits of

gold and rock downstream. As they

rub against each other. In

and polished. The

way

along, they

they are smoothed

rock that have been smoothed

bits of

are called pebbles.

this

move

Many

pebbles together are called

gravel.

Gold

is

heavier than gravel. So the lighter pieces of

gravel are carried farther downstream than the gold.

The heavier gold bottom of the

is

river

dropped upstream.

bed with

Gravel beds where gold (

PLASS-irs )

.

is

It settles at

the

larger pieces of gravel.

found are called placers

Taking gold from placers

is

called placer

mining.

The gold miners

of 100 years ago separated bits of

gold from the gravel of placers by panning. The miner

put

bits of

gold and gravel from the river bed in a shal-

low, round iron pan.

He

He then let water flow into the pan.

shook the pan at the same time. The shaking sepa22

rated the heavier bits of gold from the Hghter gravel.

Then

the gravel could be poured

oflF

with the water,

leaving small lumps of gold in the pan.

Most So not

of the gold in placers has already

much

placer mining

is

been found.

done any more.

U.S. Geological Survey

Placer mining

Watersheds and Divides

Two end

drops of rain that come from the same cloud can

their trip to the sea thousands of miles apart. This

happens

in

South America. The Juruena River and the

Paraguay River both apart.

start in Brazil

only three mile

There they have only a small mountain

between them. Water flows down one

(rij)

We say that this side of th.

ridge into the Juruena River. ridge sheds

its

water into the Juruena River. So

of the Juruena watershed.

rid^

side of tf

it is

part

The other side of the mountain

sheds water into the Paraguay River. So

it is

part of the

Paraguay watershed. The ridge between the two watersheds If falls

is

called a divide.

a rain cloud

from

it

is

over the divide some of the rain that

some also The Juruena River flows Amazon River. The Amazon River

flows into the Juruena River. But

flows into the Paraguay River.

north into the great

.

.

.

some goes

into

the ocean here.

.

Juaruena Rjver Of the

rai

that falls h^re

ParaeuayFiver

na River

and some goes he ocean here

into

empties into the Atlantic Ocean. The Paraguay River flows south into the Parana River.

The Parana River

empties into the Atlantic Ocean, too.

It

Atlantic

Ocean 3,000

empties into the

Amazon apart may

miles from where the

does. So raindrops that fall only three miles

reach the sea 3,000 miles apart.

Some watersheds

are very large.

The watershed

of

the Mississippi River covers almost half of the United States. All the

sippi River

is

that sheds

its

land that sheds

The

water into the Missis-

water into the rivers that flow into the

Mississippi River

called

its

in the Mississippi watershed. All the land

is

in the Mississippi watershed, too.

rivers that flow into the Mississippi River are its

tributaries

(

TRIB-you-ter-rees )

The Mississippi watershed

Rivers That Are Pirates

Men who

the seas and rob other saiHng ships are

sail

called pirates. Rivers are sometimes pirates, too.

become

pirates

when

They

they capture the waters of other

rivers.

The

pictures

on

this

tured some of

page show how the Shenandoah

became a pirate when it capthe water of the Beaverdam Creek in the

River became a pirate.

It

Blue Ridge Mountains of Virginia.

The Potomac River and

the

Beaverdam Creek both

used to flow through water gaps in the Blue Ridge Mountains. The

first

picture shows

what they looked

The Potomac River was stronger than the Beaverdam Creek. It cut its valley faster. So the valley of the Potomac became deeper than the valley of the

like then.

Beaverdam.

The Shenandoah River flows into the Potomac River. The head, or beginning, of the Shenandoah River was on one side of a divide. The head of the Beaverdam

Water

Creek was on the other side of the divide.

The Shenandoah flowed

into the deeper valley of the

Potomac. So the Shenandoah flowed faster than the

Beaverdam. Because

it

flowed

Shenandoah

faster, the

River was stronger than the Beaverdam Creek.

Both

rivers kept

wearing away the divide between

them. The stronger Shenandoah wore away quickly. Finally the divide

The path

its

was worn away

a river follows

is

called

its

flowing into the Beaverdam.

Shenandoah River

more

altogether.

The Beaverdam

channel.

Shenandoah channel was steeper than the channel. So the head of the

side

Beaverdam Creek stopped It

began

to flow into the

way

the Shenandoah

instead. In this

became a pirate which beheaded the Beaverdam Creek. The head of the Beaverdam Creek used to flow through a water gap. But water does not flow through the old

Beaverdam water gap any more. The water gap has become a wind gap. The second picture shows what the rivers look like

Wind gap

now.

The Lower River After a river leaves the mountains,

becomes the

river.

slopes a flat.

it

The lower river may flow over land that Or it may flow over land that is almost So the lower river flows more slowly than the upper

lower

river.

little bit.

Because the river has slowed down so much,

cannot carry the load of sand and

soil it

had when

it

it

left

the mountains.

When land that

a river flows is

very

drops most of layer of sand

its

and

flat,

down from steep mountains onto it slows down very quickly. So it

load of soil

soil

once.

The

been dropped looks

like

and sand

that has

all at

U.S. Geological Survey

A fan

Some fans are very large. The Merced River down from the high Sierra Nevada Mountains in

a big fan. flows

Cahfomia.

As the

fan

Its

more and more and

soil

is

river flows

80 miles through

of the sand

lower valley,

its

and

dropped along the

are

across. it

loses

The sand

soil it carries.

river bed.

In the springtime, heavy rains and melted snow

fill

the

They make the river spill out over its banks into the is called a flood (flud) The floodwater picks up soil and sand from the river bottom and spreads some of it over the valley land. The valley land is called the river.

valley. This

.

river's flood plain.

After a long time the flood plain

covered with a deep layer of sand and soil

soil.

have many chemicals (KEM-i-kals)

is

The sand and

in

them. These

chemicals were in the rocks in the mountains. They were

washed out Growing

of the rocks

when

the rocks weathered.

plants use these chemicals as food. So the land

of a flood plain

is

fertile (FUR-till), or rich in

At the same time, heavier

been dropped

in

bits of

plant food.

sand and

low ridges along the

soil

river banks.

ridges are levees (LEH-vees). These levees are

have

These

made by

nature. So they are called natural levee's. Natural levees

build up higher and higher each year. times ten or fifteen feet high. valley

from

floods.

29

They

They help

are some-

protect the

Meandering

The lower

river looks like a big snake

many bends and the time.

looks

all

looks

when

turns. It keeps

The lower

loses old

it

because

it

has

changing the way

it

way

it

river

changes the

bends and makes new ones.

Engineers (EN-jin-eers) wanted to find out

why

the

lower river bends and turns. They found that the bends

and turns are made by the

soil

and sand that the

river

They found this out by doing an experiment. They made a model of a river with a straight channel. They built the channel out of sand. They found that as carries.

soon as water flowed through the channel, the model river

began

tures

on

The

this

first

bend or meander (mee-AN-dur). The

to

page show how

this

happened.

picture shows the straight river channel.

Straight channel

The y^

river

wore away

the bank here

PBBI

.and built a sand bar here

30

pic-

The second first

began

picture shows the channel

to flow

wore away the carry

away

quickly as

it

at B, a little

at

began

bank

it.

The water But the

at A.

wore away. So

soil

below A. This made a sand bar at

to flow

B made

at B.

the river began to flow

at C.

the bank at C.

The

more

quickly,

third picture shows

way

ing

up sand bars along the whole

the water kept wearing

big snake, with

it

wore

what hap-

pened at C. But then another sand bar was made this

like a

as

more quickly between the sand bar

When

looked

bank

the river narrower. So the

the

bank

channel

and sand were dropped

B and

away

in the

river could not

the bits of soil and sand from the

The sand bar river

through

river

when water

at

away banks and

D. In

build-

river. Finally the river

many bends and

turns.

Then the river wore away the bank here

—

and built another sand bar here

31

A River'Changes Its Bed The Yellow River of China It

flows 15 feet above

very is

its

an old meandering

flood plain.

30 feet above the

river.

When the river is When the river

plain.

it may break through one of its natural levees. may leave its old bed below the break and make

so high,

Then a

full, it is

is

it

new

channel.

For 500 years before 1852, the Yellow River had been flowing into the Yellow Sea. After a flood in 1852, the

Yellow River changed of Pe-chi-li,

its

bed.

It

began

to enter the Gulf

250 miles north of the Yellow Sea.

The floods

of the Yellow River

In 1887 a million people were

have been very

drowned

terrible.

in a flood.

The

Yellow River has been named "China's Sorrow."

make the channel of the Yellow River deeper and straighter. They hope The Chinese government

that this will keep

it

is

trying to

from flooding and from leaving

bed.

?rtto

the sea here

its

A

A

river that

River Changes

Its

Face

meanders keeps changing

banks along one meander

may be

along the meander that came before

wears away the the second one.

first

meander

The

first

its

it.

faster than

The

So the river it

meander comes

closer to the second one. After

looks.

harder than the banks

many

a small strip of land between them.

wears away closer

years, there

Then

it is

is

and only

easier for

the water to flow across this strip of land than to flow

around of

it.

The meander is cut off, and the river The meander that has been cut

bends.

its

narrow,

like a long,

swampy

lake. It

is

loses

one

off looks

called a

bayou

(BYE-you). Cutoffs river

is

river.

happen more

easily during floods.

When

flooded, the water flows over the banks of the

Then

it

can easily wash away the narrow

strip of

land between two meanders.

Before a meander is

a

cut off

After a meander is cut off

Taming a Wild River Most

of the time

meandering

rivers are very quiet

and harmless. But they may become very dangerous.

They may

flood their broad valleys.

Then they may

kill

people and animals and carry away houses.

When

a lot of rain

falls

or

snow

melts, the water in a

keep the

river rises. Usually the natural levees

overflowing

banks. But sometimes the river channel

its

has to carry so

much water

levees anyhow.

Then

Farms, towns and

that the water flows over the

the river floods

floods.

The

rivers

One way to tame

its

have been

cities

valleys of large rivers. So the valleys

from

from

river

valley.

built in the fertile

must be made

safe

must be tamed.

a river

by building

is

levees along

its

banks. Hundreds of miles of levees have been built along

the banks of the Mississippi River and

Another way to tame a

When meanders shorter. This

are cut

makes the

river

is

its

the path of the river

off,

river flow faster.

can carry more water. So

tributaries.

by making

it

doesn't rise

cutoffs. is

Then the

made river

as high during

floods.

When to

a river wears

away

meander. Protecting the

tame a

river.

Mats made

its

river

banks, the river begins

banks

of concrete

is

a third

way

to

and heavy wire are

placed over part of the river bed. They go from the shore 34

a 1254551

a:

to the deepest part of the river channel.

A

fourth

way

across the river.

to

tame a

river

is

by building a dam

When there is a heavy flow of water into

the river, the water collects in a large lake behind the

dam. Then the is

stored

is

river does not rise.

A lake

in

which water

called a reservoir (REZ-ur-vwar).

A

levee near

New Orleans

Mississippi River

Protecting banks with concrete mats

Commission

Making

Electricity

made at electric power plants. The machines that make electricity are called generators (JEN-ur-ay-tors). Some power plants use the power of steam to turn the generators that make elecThe

electricity

people use

is

Other power plants use the power of flowing

tricity.

water to make

electricity.

In some places there

flowing water. In these places electricity

is lots

of

made by water

is cheaper than electricity made by steam power. One of the first power plants to use flowing water to make electricity is at Niagara Falls. A tunnel was dug

power

from the bed of the

river

above the

the river at the bottom of the

falls.

falls to

the bed of

Very strong water

wheels, called turbines (TUR-bins), were placed at the

bottom of the tunnel. Water

falling

through the tunnel

River

Water falls through the tunnel

.

The turbine turns the generator,

.

making

and makes the turbine turn very fast

How

electricity

Water flows into the river again

water power makes electricity

U.S. Bureau of Reclamation

Grand Coulee Dam

made the turbines

turn very

fast.

The

turbines were con-

nected to electric generators. So the electric generators turned, too,

A new

making

electricity.

power plant which uses the water of the Niagara River was finished in 1961. It is the largest electric

plant run by water

power

in the

Water flowing over a dam

is

United

States.

like a waterfall. It

used to turn turbines which are connected to generators. There are electric

Coulee

Dam

power

Hoover

Dam

State

and

dams

are used to prevent floods, too.

at

built in the

plants at

on the Columbia River

in

can be

electric

Grand

Washington

on the Colorado River. These

Dams have been

Tennessee River. They make

electricity for

the people of Tennessee, Mississippi and Alabama. also prevent floods of the

Tennessee River. 37

They

Rivers and Travel

Men

have sailed on

years. It

was the

rivers

easiest

way

and for

seas for thousands of

them

to travel.

So they

often settled along the shores of rivers and seas.

The first American settlements were on the Atlantic Ocean or on rivers that flowed into the Atlantic. As these settlements grew, they began to trade with each other

more and more. Settlements on the upper part could send their goods downstream on

rafts

of a river

and

flat-

The river current did the work. The rafts and flatboats were built for one trip only. They were cheap. But they were slower than ships. Many settlements along rivers could be reached by ships that safled across the ocean. Ocean ships could travel up the St. Lawrence as far as Montreal, Canada.

boats.

But ocean ships could not reach the settlements along

^iSSi

A f latboat

the Great Lakes.

Canal was

To reach

built. It

was

the Great Lakes, the Erie

finished in 1825. It connected

Lake Erie with the Hudson

River.

Ocean

ships

and Great

Lakes ships couldn't travel through the canal. Their goods had to be unloaded onto canal barges. So travel through the canal was slow.

Then

railroads

were

built. It

the goods of ocean ships canals

and

rivers

by

became cheaper

railroad. So, for

were not used

as

much

to

many

send

years,

for carrying

goods.

But now

rivers are

being used again. With the help of

dams, deep canals, and locks, rivers have been opened to large ships.

Now ships can use the Tennessee River even

during the dry season. The

ocean ships to travel

on

all

the

St.

Lawrence Seaway allows

way to Lake Superior. been made safer and

the Mississippi River has

Travel better.

ontreaf

UN^TED STATES Ocean ships now

travel to the Great

Lakes

Where People Live

New York City, Tokyo and London are the largest cities in the world. All of them are near rivers. All of

by ocean

ships.

too, are usually

m

them can be reached

Small

cities

and towns,

near rivers or the sea.

People built settlements on rivers for

'

¥'

\

many

reasons.

to get

away quickly

ger.

A

They wanted if

be able

to

they were in dan-

nearby river made a

fast

escape

possible.

They built their

settlements where they

could get food easily. They could catch fish

and oceans. They could hunt

in the rivers

animals in the woods along the shores. They could grow plants for food in the fertile soil of

They built could trade

the river valley. their settlements

easily.

where they

The barges and

boats

of a river joined one trading post with

another.

The

early settlers along the

River used the river in their living.

ikffiliFLC

Hudson

many ways

to earn

At Haverstraw, they used Hudson River clay to

make

bricks.

down

Ships sailed

the river from

New-

burgh and then up to the far North Atlantic

Ocean The

to catch whales.

rivers.

The

to

cut ice from the frozen

settlers

ice

went

keep food from Loggers cut

into people's iceboxes

spoiling.

down

near the

tall trees

upper Hudson. They floated them mills

to saw-

downstream.

At Troy, water that flowed into the

Hudson River was used to turn factory machinery. This helped make Troy a city of

many

factories.

Albany began It

was

as a post for fur traders.

in the center of Indian territory.

Furs were shipped from Albany

Hudson were

to

New

York

City,

down

the

where they

sold.

The

things people do to earn a living

keep changing. But most people near rivers or the

still

live

sea.

y.i

Water

for Plants

by animals and people. GrowThey get it from the soil through where there is plenty of rain, there

Plants are used as food

ing plants need water. their roots. In places is

always water in the

enough

rain, rivers

ervoirs are built

In places where there

soil.

is

not

can be used to water the land. Res-

where the

river valley

is

narrow and

deep.

Water keeps flowing out stream,

all

of the reservoir in a steady

year round. So even

when

it is

dry, the river

keeps flowing. Channels and ditches carry the water to fields

way

and orchards. Bringing water

is

to the land in this

called irrigation (ih-rig-GAY-shun).

and Grand Coulee also flood control

Dam

Hoover

are irrigation dams.

dams and

electric

Dam

They

are

power dams.

Water for People

Towns and live in

them.

cities

have

Some

cities

to get

water to the people

water of streams and rivers in

reservoirs.

Water

is

carried in pipes from the reservoirs to the towns cities for

New

then

and

people to use.

York City gets most of

in the Catskill skill

who

get their water by storing the

its

water from reservoirs

Mountains. Water from one of the Cat-

reservoirs travels 125 miles to

New

York City.

42

*

Los Angeles, California, gets

its

water from the Colo-

rado River, 300 miles away.

Keeping Water Clean

The people who them

live

near rivers do not always use

dump

wisely. Factories often

rivers.

Sometimes sewers empty

water of these

rivers

is

polluted (po-LUTE-ed). rivers.

Even

into the rivers.

no longer pure. It is

It

The

has become

not safe to bathe in these

the fish in a polluted river die.

People must learn that they

their wastes into the

how

to get rid of their wastes so

do not pollute the

rivers.

USOA

Dead

fish in a polluted

stream

Photograph

Deltas All the rivers of the world reach the sea sooner or

The

later.

may be an

sea

Or

inland salty lake.

it

may be

one of the oceans. The place where the river enters the sea

it

called the river's mouth.

is

A

river

sometimes drops the

carries at

rest of the

sand and

mouth. This happens where the sea

its

very quiet. The water of the Mediterranean Sea quiet.

soil

The water of the Gulf

of

Mexico

is

is

is

very

very quiet, too.

So a river that flows into the Mediterranean Sea or the Gulf of Mexico slows

drop

its

load of

at the river's

soil

mouth

down

very quickly. This makes

and sand. The sand and in the

Greek

letter "delta" looks like

and sand

Some

rivers

is

has been built on

Ganges River

Some no

rivers

delta. It

distance

deltas.

The

so large that the city of it.

The

in India

this layer

have no

deltas, too.

The Columbia River has down quickly at its mouth. So

deltas.

soil it carries

by the waves

delta of the

New Orleans

Nile River in Egypt and the

have very large

does not slow

the sand and

a triangle. So

called a delta (DELL-tuh).

have very large

Mississippi River

up

shape of a large triangle. The

of soil

is

soil pile

it

are spread out over a great

of the Pacific Ocean.

A river with a delta enters the sea through many channels.

Dried-out channels at the mouth of the Mississippi 44

I River

tell

us that

Po River in city of It is

its

Italy has

delta has

moved

moved. The delta of the

15 miles in 1,000 years.

The

Adria used to be a seaport at the mouth of the Po.

now

15 miles inland.

Delta of the Mississippi River

The Journey

Drop

of a

When you boil a pot of water,

Water

of

the heat from the stove

changes the water to water vapor or steam.

We say that

the water evaporates (ee-VAP-or-ates). River water evaporates, too.

As a

down

river flows

to the sea, the heat of

the sun changes some of the water to water vapor.

the vapor rises up into the

The

river

of the ocean.

water that reaches an ocean becomes part

The oceans cover most

of the earth. Great

amounts of water evaporate from the oceans,

When cooled. little

water vapor

The

rises

high up into the

drops of water or to bits of

little

heavy that they rain

too. air,

it

is

cooling changes the water vapor back to ice.

A

drops of water or bits of ice together times, the

Then

air.

a cloud. At

drops of water or bits of ice become so fall to

and

The away

the ground as rain or snow.

and melted snow may run

into the streams

lot of these little

make

rivers.

off the

land right

Or they may become ground

water which goes into the streams and rivers very slowly. Streams and rivers make their

way

to seas

and oceans.

Then the story begins all over again. The story of the journey of a drop of river water is called the water cycle (SY-kuU). The water cycle happens over and over again. So the story of the journey of a drop of river water a story without an end. 46

is

The Water cycle

WORD Bayou

LIST

(BYE-you) — A swampy lake formed when

a river

is

cut

a meander of

off.

Delta (DELL-tuh) the sand and

— Land

mud

built

up

at the

mouth

of a river

by

that the river drops there.

Erosion (ee-ROW-zhun)

— The wearing away of land by flowing

water.

Evaporation

(

ee-vap-or-AY-shun )

— Changing

a liquid,

like

water, into vapor or gas.

Flood plain (flud) — The level land in the broad valley of an old river, where the river drops sand and soil during floodtime. Generator (JEN-ur-ay-tor) Gravity

— The

—A

Horizontal (hah-rih-ZON-tuU) Irrigation

(

machine that makes

pull of the earth that

ih-rig-GAY-shun )

makes things

electricity.

fall.

— Level, like the top — Bringing water to

of a desk.

dry land

through pipes and ditches.

Levee (LEH-vee) — A wall the low land next to it.

of earth along a river that protects

— One of the turns in a winding river. (REZ-ur-vwar) — A lake in which water is stored. (TRIB-you-ter-ree) — A stream that empties into an-

Meander (mee-AN-dur) Reservoir

Tributary

other stream.

Turbine (TUR-bin) — A wheel that is turned when flowing water or a gas hits it. It is used to turn an electric generator. Vertical (VUR-ti-kuU)

— Standing

straight

up and down,

like a

tree.

Watershed

— The

land from which water drains into a

Weathering — The breaking up of rocks into air and water.

48

soil

river.

and stones by