Increasing Role of Large Reservoirs in Sustaining Urban Water Supplies in India

Rapid urbanization and industrialization are the major factors behind growing urban water demand in India. Incidentally, the large urban areas are experiencing faster growth in population, and most of them are in arid and semi-arid regions, which are naturally water-scarce. As a result, water supplies from local water sources including aquifers are falling far short of the high and concentrated demands in most urban areas. Under such situations, these large cities have to rely on distant large reservoirs. Understanding the pattern and sources of urban water demand is important for sustaining water supplies in cities. The analysis of Class I cities (> 0.1 million population) and Class II towns (population 0.05 to 0.1 million) shows that cities with larger population size have much higher level of dependence on surface water sources. The Population Elasticity of Water Supply (PEWS) change with time and space for Class I cities it was 1.23 in 1988, 1.29 in 1999, whereas it has gone down to 1.05 in 2008. It also shows that Class I cities have better water supply than Class II towns (PEWS was 0.33 in 1988, 0.76 in 1999 and 0.82 in 2008). Given the structure and pattern of urban population growth, economic conditions and water demands, large reservoirs will have a much bigger role in meeting urban water supply needs. • During 1901 to 2011, urban population in India has increased more than 14.7 times surpassing India's total population growth, which has increased by 5.2 times • In 2011, 31.16 % (377.11 million) of India's population is living in urban areas, which is expected to increase up to 40 % or 550 million in 2021 (Lundqvist et al., 2003) • A large share of urban population live in Class I cities in 2001 as compared t