Give your opinion about wheather hydroelectric plants are environment-friendly or not?

Explanation

(1) Hydroelectric plants are advantageous in some respect while in some aspects it does create problems.
(2) Hydroelectric power generation does not need burning of fuels. Therefore, there is no problem regarding combustion of fuels and release of toxic pollutants.
(3) Electricity can be obtained as and when required if there is enough water in the reservoir.
(4) Water is replenished every time when there is sufficient rainfall.
(5) All the above facts give an impression that hydroelectric power genetation is eco-friendly but it is not.
(6) Many villages and settlements are submerged when a dam and reservoir is constructed. The displaced people are given re-settlement, but it causes lot of emotional trauma to people.
(7) Biodiversity is affected as forest lands is submerged. The river flow is obstructed by the dam which affects the aquatic organisms residing in such water.
(8) Due to excessive pressure of water on land, it is said that the region gets prone to earthquakes.