Question

Make a report on the useful and adverse effects of constructing dams on rivers (REPORT)

Answer 1

advantages
If electricity is not needed, the sluice gates can be shut, stopping electricity generation. The water can be saved for use another time when electricity demand is high.
The lake's water can be used for irrigation purposes.

When in use, electricity produced by dam systems do not produce green house gases.
The lake that forms behind the dam can be used for water sports and leisure / pleasure activities. Often large dams become tourist attractions in their own right.
Once a dam is constructed, electricity can be produced at a constant rate.

disvantage
The building of large dams can cause serious geological damage. For example, the building of the Hoover Dam in the USA triggered a number of earth quakes and has depressed the earths surface at its location.

People living in villages and towns that are in the valley to be flooded, must move out. This means that they lose their farms and businesses. In some countries, people are forcibly removed so that hydro-power schemes can go ahead.

Building a large dam alters the natural water table level. For example, the building of the Aswan Dam in Egypt has altered the level of the water table. This is slowly leading to damage of many of its ancient monuments as salts and destructive minerals are deposited in the stone work from rising damp
caused by the changing water table level.

The high cost of dam construction means that they must operate for many decades to become profitable.

Answer 2

USES
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1)water does not get wasted
2)we can store more water and we can use it for our daily needs
3)there wont be water scarcity in months of summer
4)we can stop the water from getting into ocean unnecessarily
5)we can have more water for farming purposes etc
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HARM
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1)it is very economical
2)forest ares gets destroyed
3)as many plants will inside water methane will be released which is harmful
4)many people will lose their homes , farmland
5)there is a cause of floods
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