GEOGRAPHY CT-2 NOTES

"Superdams"

Many countries build massive dams. They are used to control

rivers and provide water for huge irrigation projects. This unit

looks at two huge schemes where 'superdams' are being built:

why do people build superdams?

what impacts do superdam projects have on local

people and the environment?

• why do some people think that small-scale projects are better?

Why do we need

superdams?

After heavy rain, some rivers flood,

causing loss of life and damage to

property. By building a dam, flood

water can be captured while the

river flow is high. Water can then be

released when the danger of flooding

has passed. Dams can therefore

control flooding. They are also used to:

generate hydro-electric power,

a clean and renewable

form of energy

⚫ supply water for homes,

industry, and agriculture.

The Hoover Dam in the USA was

the world's first superdam, Since

then, there have been many

superdam projects. Many have

been in developing countries.

1 a) Use the data in B to draw bar

graphs of superdams under

construction. You could cut out

and paste your bars on to a

world map.

b) In which parts of the world are

most of the new superdams

being built in developed or

developing countries?

Akosombo-an early

superdam

One of the first superdams to be

built in the developing world was

on the River Volta in Ghana. The

dam was completed in 1964 at a

cost of US S 120 million. Its aim

was to produce the huge

quantities of hydro-electric power

needed to smelt bauxite, the ore

of aluminium. The aluminium

smelter at the port of Tema uses

70 per cent of the electricity

produced by the dam. Most of

Ghana's aluminium is exported to

the USA by the American

company who own the plant.

99% of Ghana's electricity is produced by the dam. Surplus electricity is

exported to Togo, Benin, and Ivory Coast, earning foreign exchange for Ghana.

Water from Lake Volta is used to irrigate the dry savanna landscape to the

north of the dam

A large fishing industry has grown up on lake Volla

Since the completion of the dam, coastal erosion in parts of Ghena and Togo

has become more rapid.

Most of Keth, in Ghana, has fallen into the sea.

Coast roads in Togo fiave been washed away.

Rock groynes could be built to protect the coast, but would cost around

US $2-3 million per kilometre of coastline.

2 Using map C, copy and

complete the following

sentences:

The main tributaries of

Lake Volta are the .......

Volta in the north-west,

the White Volta in the

........ and the........in the

north-east. Lake Volta is

........km long from

Tamale to the dam at

3 Study diagram D.

a) In which direction

does the Guinea

current flow?

b) Explain in your own

words how the

construction of the

dam is linked to

problems of coastal

erosion,

c) Use map C to name

one town in Ghana

and one in Togo that

may be affected by

erosion.

4 Summarize the

advantages and

disadvantages of

Akosombo Dam for

Ghana and its

neighbouring countries.

"The Three Gorges Dam in China"

The Three Gorges Dam is currently being built on the

Yangtze River in China. The Yangtze is the third

largest river in the world, with a huge flood plain

where 75 million people live. It is a dangerous and

unpredictable river In July 1995 100 million people

were affected by flooding on the Yangtze. One

million homes were destroyed and over 1000 people

died in the worst fioods since 1935. The flooding was.

caused by torrential rain since May, and the thaw of

snow in the mountains at the source of the river.

Deforestation was also blamed. The floods were

used as a powerful argument to complete the Three

Gorges Dam. The finished dam will be 175 metres

wide, creating a reservoir 600km long. The proiect

will cost US $20 billion.

1 Use map B and an atlas to name:

a) the river in northern China that flows into the

Yellow Sea

b) the river in southern China that flows into the South

China Sea near Hong Kong.

2 a) Describe the four aims of the Three Gorges project.

b) Imagine you work for the Chinese authorities.

Use map B as evidence to explain why the dam

is necessary.

3 The World Bank believes that living standards in China

will be improved if electricity production is increased.

Suggest how this might happen.

The main aims of the project are:

To control the river and prevent flooding. Records

show that floods have occurred on average every ten

years on the Yangtze River. In 1935 a flood killed

142 000 people and caused extensive damage. The

basin of the Yangtze produces 40 per cent of China's

total industrial and agricultural output. Reducmg the

risk of flooding is very important to ensure future

economic growth.

To generate hydro-electric power. The Three Gorges

Dam should generate 18 200 megawatts, which is

18 per cent of China's present energy needs.

To provide a steady flow of water for irrigation.

More and more rural Chinese are leaving the land to

find jobs in China's cities. Since 1980 there has been

a steady decline in agriculture. The dam will provide

water to improve the livelihood of farmers by allowing

them to grow cash crops like flowers, as well as

cereals.

To make river transport easier. At the moment the

upper Yangtze flows down a gorge 660km long

and drops down 139 rapids. When the reservoir has

been filled, the rapids will be flooded to a safe depth.

Ships of 10.000 tonnes will be able to travel up the

river, cutting transport costs by 35%

What are the costs

of the dam?

The Three Gorges Dam

will flood 632km² of land

including 240 000 hectares of

form land, and two cities..Over

She million people will need to

be resettled. The loss of farm

land and of people's homes

causes a great deal of worry

amongst local people. Where

will they live and work? Will

they be fully compensated for

their lost homes and

businesses?

What about the

environment?

Some argue that the dramatic

scenery of the gorges will be

ruined when the water levels

rise by an average of 40m up

the cliff faces:

Conservationists fear that the

freshwater dolphin will no

longer be able to live in the

fast-running water below the

dam. Another rare creature, the

huge Chinese sturgeon, swims

up river to spawn; but its route

will be blocked by the dam.

Forest clearance in the area is

also causing concern. The pie

charts in C show that most of

the area has already been

deforested. As the dam is built

and people are moved to new

sites, more trees will be cut

down to create farm land, and

to provide wood for building

and fuel. Once areas of land

are left bare and unprotected,

soil erosion quickly follows as

diagram C shows.

4 Imagine that you are either a conservationist or one of the families that will be

forced to move to make way for the dam. Write about how you feel.

5 a) What percentage of forest was left in the area in 1950 and in 1995?

b) Use diagram C to explain how deforestation can lead to silting-up of the

reservoir.

c) Why is silting up of reservoirs a problem. and how can it be prevented?

6 a) Rank the arguments for the dam in order of importance. giving reasons for

your order

b) Do the same for the arguments against the dam.

c) Do you think the advantages outweigh the disadvantages?

Are there alternatives to superdams?

How can developing countries provide irrigation water and

hydro-electric power without causing massive environmental

damage or moving thousands of people from their homes?

Small-scale solutions to water shortage:

Adgaon is a village in the Indian state of Maharashtra. It is

240km south of the site of the Sardar Sarovar superdam on the

"Narmada River. Adgaon receives an. average of 500mm of rainfall

a year. Most of this rain falls between July and October, much of

it in just ten days. The villagers suffer during the rainy season from

the effects of unpredictable rainfall, lack of drinking water, and

soil erosion.

The villagers have now constructed small earth dams across

the streams. This is an example of appropriate technology. The

earth dams use local materials and the skills of local people. They

are cheap to build and easy to maintain. Water is stored for several

months during the dry season. Farmers can later dig out the fertile

silt that has wasfied down and been trapped behind the dam. They

spread the silt on their fields, and it helps keep the land fertile.

The villagers have also built earth walls or hunds along the

contours of fields. These slow down the run-off of rainwater,

trapping the water where it falls. This is known as rainwater

harvesting. Bunds also prevent soil erosion. They have been used

in other arid areas, such as the Sahel on the edge of the Sahara

as you can see in photo D.

The results in Adgaon are impressive; the wells now have water

and there are fish in the main stream, even in December when

the river used to be dry. Acacia, eucalyptus, and banana trees

have been planted and now thrive in Adgaon.

Large-scale schemes which require a

lot of money are not an appropriate

form of development for developing

countries like India. Countries

should develop in more sustainable

ways that require less money and

involve people on a local scale.

1 Describe how the rainfall pattern in Adgaon causes

problems in the water supply.

2 Look at photo C. Explain why small earth dams such

as this can be more helpful to the local community

than a superdam such as the Three Gorges.

3 Imagine you work for an aid agency in Africa.

Describe what bunds are to local villagers and explain

how they can help conserve water.

4 a) Using map E and an atlas, name countries A-D.

b) Using F, draw graphs to show the area affected by

soil erosion in each region.

c) Which region has the largest percentage of its area

affected?.

5 Explain why the developments in Adgaon can be

described as appropriate.

6 Describe the advantages and disadvantages of small-

scale hydro-electric power schemes compared to

large projects like the Three Gorges.

Small-scale solutions to energy production

In China small hydro-electric power stations (like

photo A. page 58) are built by local communities

and subsidized by the government. They need less

money to build and cause much less damage than

superdams although each unit of electricity is

slightly more expensive in the long term. They can

be maintained and bperated by rural communities

and integrated to form a local grid. These small-

scale schemes are a healthy answer to local power

shortages but can only partly meet power generation

needs on a large scale.

Dammijng the Narmada River

India gets 28 per cent of its electricity from hydro

electric power, but as its economy grows, more

electricity is needed. The Indian government favours

big projects such as the Narmada project. This

involves building two superdams, one at Sardar

Sarovar, the other at Narmada Sagar. There will also

be 30 large dams, 130 medium ones and 3000 minor

ones along the Narmada and its tributaries

The aims of the Narmada project

The Indian government expects the project to:

• provide water for irrigation in Gujarat, an arid part

of India with a population of 20 million

• provide water, and generate 1450 megawatts

of cheap electricity to boost industrial

development across Gujarat state

- provide protection from flooding for

750 000 people

What are the issues in Gujarat?

The aim of the Sardar Sarovar reservoir is to solve the water problem in the dry

state of Gujarat. Canals will carry water from the reservoir to areas of drought.

However, it is feared that much of the water will go to the rich cotton-growing

areas and not to the small rural communities that need it. The huge cost of

aqueducts needed to transport the water may outweigh the benefits, especially

since existing canals leak badly,

What are the issues in Madhya Pradesh?

Up to 1.5 million people will lose their homes and have to be settled elsewhere,

Local people fear that they will not be properly compensated. The Narmada

Sagar reservoir will submerge 90 000 hectares of land, and will only irrigate

123 000 hectares. Deforestation and the increased grazing of livestock in the

area will lead to soil erosion. Not only will the farm land suffer, but soil erosion

will lead to silting-up of the reservoirs.

1 Use map A. Copy and complete the following.

The Narmada flows from ....... to........ It is .......km

from its source to its mouth in the Gulf of .........

2 a) In which state is:

(i) the Sardar Sarovar Dam

(ii) the largest part of the Narmada drainage basin

b) Which state has no major dams on the. Narmada?

3 Which of the two superdams will submerge

a) mainly farm land?

b) 35 per cent forest?

4 a) Use the data in table B to draw a climate graph for

West Gujarat and Nagpur.

b) Use your graphs and climate graph C to describe

how the climate changes as you travel.from the

source of the Narmada westwards to Gujarat's

border with Pakistan.

c) Use these graphs to help explain the aim of the

Sardar Sarovar Dam.

5 Summarize the main advantages and disadvantages of

the Narmada project using these headings:

1 Using graph B, describe how India's economy

is growing.

2 a) Working in groups of four, produce line graphs

to show India's growing electricity production.

b) Describe .the trend of each graph you have

drawn. Which is growing faster, and

which slower?

c) Why does the Indian government believe that

the Narmada project is necessary?

The economic argument:

India telies heavily on hydro-electric power, as you

can see from table C. There are already fourteen

superdams and many more are planned. But still the

state power companies cannot keep up with demand

and power cuts are common. At peak times, 20 per

cent more electricity is needed than is being

produced. Meanwhile, the Indian economy is growing

quickly. Exports rose by 20 per cent in 1994.

Government ministers believe that the benefits of

large-scale projects will 'trickle down' to help the poor.

The rights of tribal peoples

The Narmada project will flood a total area of 3500km²

of forest and 600km2 of productive farm land. Up to 15

million people will lose their homes and have to be

settled elsewhere. The majority of the people to be

resettled are tribal communities such as Bhils, Pardhans,

and Kols who have created a subsistence way of life based

on farming, fishing, and forestry. Families who have to

move have been promised five hectares of land each, but

most will be offered poor quality grazing land in exchange

for their once rich land close to the river. Over-grazing and

deforestation of this drier land will lead to soil erosion.

Some tribals have already been relocated and are now

working in.cotton factories. For the first time they are

earning money, but they have lost their communities; their

traditional way of life, and their culture. There is a strong

anti-dam feeling among the tribals who cannot see any

benefits for themselves. Some feel so strongly that they

say they would rather drown in their homes than move.

Environmental impacts of the irrigation scheme:

The Sardar Sarovar Dam will provide irrigation water

for Gujarat. Environmentalists fear that irrigating this

arid region will cause the water table to rise. The soil

will become waterlogged and natural species of

plants will die Salination will also be a problem. as

shown in diagram D. All water contains some

dissolved salts from the rocks it has passed over or

through. Irrigation causes the concentrations of

these salts to increase eventually making the soil

useless for farming

3 a) Using diagram D, explain why 4 a) Imagine that you have to tell

irrigation causes:

(i) the water table to rise

(ii) salts to become

concentrated in the soil.

b) Why could installing land

drains reduce the problem of

salination?

people that their homes will be

flooded and they will have to

move elsewhere. Discuss how

you would do it. Remember, you

must try to persuade them that

it is for the best.

b) Discuss how you would go about

protesting against the scheme.

Design a leaflet or speech to

inform people of your plight.

Review

Superdams are being built in

many developing countries. The

main aims are:

- to generate power

- to provide water for

agriculture and industry

- to control flooding.

However, smaller scale schemes

are not as costly and do not

involve large-scale resettlement

or loss of land. They provide a

more sustainable form of

development.

5 Design a poster or leaflet

describing the advantages and

disadvantages of superdams.

6 Review this unit by describing

the aims of the Akosombo,

Three Gorges, and Narmada

projects.