Agriculture currently produces only 30% of total income in the Telangana region, but it remains the basis for survival of nearly 78% of the population. During the 53-year period, 1956-2009, Telangana lost 2.92 lakh hectares of tank irrigation. Meanwhile, despite the high cost of irrigation – both in capital and operating costs – over the same period the area irrigated by tube wells has grown up. The latter is entirely dependent on the recharge of groundwater and the availability and cost of power.

The decline of groundwater levels in India by 5-10 m is usually explained as a result of the increased number of tubewells and a decline in average annual rainfall. This article argues that the decline is the product of the destruction of indigenous systems for storing runoff water, which are essential because rainy days are very few and erratic.

Climate change will affect water supplies in south Asia, where high-intensity floods and droughts are expected in the future. Increasing water storage is a key adaptation strategy, and the experience of irrigation tanks illustrates both the potential and challenges of this adaptation response.