ABSTRACT
The total annual utilizable water resources in India is 1086 km3, which is only 4% of world’s water resources. The total annual utilizable resources of surface water and groundwater are 690 and 396 km3, respectively (National Commission for Integrated Water Resource Development, 1999). Consequent to rapid growth in population and increasing water demand, stress on water resources in India is increasing, and per capita water availability reduces every day. In India, the per capita surface water availability in the years 1991 and 2001 were 2300 m3 (6.3 m3/day) and 1980 m3 (5.7 m3/day), respectively, and these are projected to reduce to 1401 and 1191 m3 by the years 2025 and 2050, respectively. Total water requirement of the country in 2050 is estimated to be 1450 km3, which is higher than the current availability of 1086 km3 (Kumar et al., 2005). Human impacts on freshwater systems are substantial in most populated parts of the world. Overextraction of freshwater, mainly for agriculture, has led to significant degradation of rivers, lakes, and aquifers. Liberation of water for the environment through substitution with wastewater has been promoted as a means of reducing anthropogenic impacts (Hamilton et al., 2005a,b).
