What are the negative impacts of damming a river that are being assessed?

People make dam on the river for their own advantage. There are various reasons for damming a river. To get the water on the field for agriculture, producing electricity etc which depend on a country what is their need.

However, damming a river has some negative impacts which harms the river and the natural environment in various ways.Some of them are given below.

*When a dam is made in a river, normally the path flowing  of water is changed. As a result the river loses it's natural flow.

*Dam prevents the natural flow of water.As a result, sometimes the under water animal species are endangered as their environment is changed based on the flow of water.

* Dam makes water stopped at a certain place.After the place of dam water flows again. But when there is raining heavily the water flow prevented by dam can cause floods. Because the water flow is stopped at a place by the dam.

* The water flow of river carry the ton of fertile soil which is still helpful for the agriculture since the ancient time. Because, this soil works as a natural fertilizer. So,when the water flow stop at a place the flow of the fertile soil is also prevented.

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