Mr.

Although, three quarters of the earth area is covered by water, around 97.2 percent is in the oceans. Only 2.8 percent is fresh water, of this 2.38 percent lies frozen in the Polar icecaps and another 0.39 percent is present as groundwater. A small fraction of 0.02 percent is found as surface water, and constitutes the fresh water resources of the world. Air and soil has about 0.001 percent of fresh water. The annual terrestrial global hydrological cycle represent, 1,00,000 km3 of precipitation over land; land evapo-transpiration of 60,000 km3, and 40,000 km3 runoff from land to sea. It is this runoff water of 40,000 km3 that formed the fresh water resources available to us.2 This runoff water is used for the production of hydroelectric power. Water as a renewable resource in hydroelectric generations is tapped, particularly, in the areas with adequate water potential and steep topography. These types of geo-environmental conditions are primarily helpful in setting up of hydropower projects. Hydropower is a clean, renewable, low-cost alternative to other energy sources, it is flexible and reliable and more efficient than any other form of electricity generation. Turbines are capable of converting 90% of available energy, whereas the best of fossil fuel power plant is efficient only 50%. Another positive aspect of hydropower is its operational flexibility, its ability to change output quickly and its unique voltage control load following and peaking capabilities in hydropower projects help maintain the stability of the electric grid ensuring economic growth. Hydropower also supports various kinds of aesthetic and recreational activities. Besides, these projects help to manage floodwaters, irrigate fields, and provide water supply and harness water potential as electricity. Hydropower, thus meet the continuous rising demands for energy in a country.