Water is one of the most precious natural resources and a key element in the socio-economic development of a country. Rainfall is the main source of fresh water in India. From precipitation alone, India alone receives 4,000 cubic km of water. Of this, monsoon rainfall from June to September alone accounts for about 3,000 cubic km. A good part of it lost through the process of evaporation and plant transpiration. A large part of water percolates into the ground and is available to us as groundwater. So water is available in two different forms, viz, (1) surface water and (2) groundwater.