Spatial Variation in Water Supply and Demand across River Basins of India

Abstract

"India shows large regional differences in per-capita water supply and demand. However, a comprehensive assessment of water accounting across river basins has not been available previously. Attempts to describe the water situation in India at a national level are often misleading due to large spatial diversity in the water situation. This report uses data disaggregated at the river basin level, to assess the water supply and demand across the river basins of India, classify river basins according to water scarcities and crop production surpluses or deficits, and discuss issues that are important for future water supply and demand projections. Several factors influence Indiaâ??s future water supply and demand. These include spatial variation and future growth of the population, urbanization and income, and associated changes in dietary preferences, on the crop-consumption side; growth in crop yield, cropping intensity and groundwater use, and contribution to production from rain-fed agriculture, on the crop-production side; and future growth in other factors such as domestic, industrial and environmental water demand, and internal and international trade. These factors need to be carefully assessed in future water supply and demand projections. India's land area can be divided into 19 major river basins. The per-capita water resource availability as well as per-capita water withdrawals of these basins varies largely. Irrigation is by far the largest user of water in all the basins. The basins of the westerly flowing rivers are classified as physically water-scarce and food-dependent. The second group of basins, the Indus and Pennar river basins are classified as physically water-scarce, but these basins have significant food surpluses. The water-scarcity problems of the third group of 11 river basins are mixed, but almost all have significant deficits in crop production. The fourth and fifth groups of river basins are classified as 'non-water-scarce and food-sufficient' and 'non-water-scarce and food-surplus,' respectively."