India is a land of 14 major and 44 medium rivers. The catchment area of each of the major river is 20,000 sq. km and above while that of medium rivers, is between 2000-20,000 sq. km. Also, there are 53 small rivers each with the catchment area of 2000 sq. km. These rivers receive their top-up from glaciers and rainwater. India receives an average rainfall of 4000 BCM (Billion Cubic Metre) every year from the rain. This is what we see as surface water. Then, there is some proportion of this surface water which gets absorbed and accumulated beneath the ground, called as groundwater.
Among all the available sources of water, mankind is majorly interested in groundwater, for his drinking and majorly, for its agricultural needs. From the statistics mentioned earlier, it may seem like our country has enough water to meet the demands of the population. But here are some eye-opening points.