text: India has a growing population, and large impoverished rural population that relies on monsoon-irrigated agriculture. Weather uncertainties, and potential climate change induced weather volatilities, raise concerns of social stability and impact of floods and droughts on rural poverty. The population of India is expected to grow further at a decelerating pace and stabilize around 1.5 billion by 2050, or another 300 million people – the size of United States – compared to the 2011 census. This will increase demand for reliable sources of food and improved agriculture yields – both of which, claims India's National Council of Applied Economic Research, require significantly improve irrigation network than the current state. The average rainfall in India is about 4,000 billion cubic meters, of which annual surface water flow in India is estimated at 1,869 billion cubic meters. Of this, for topological and other reasons, only about 690 billion cubic meter of the available surface water can be utilised for irrigation, industrial, drinking and ground water replenishment purposes. In other words, about 1,100 billion cubic meter of water is available, on average, every year for irrigation in India. This amount of water is adequate for irrigating 140 million hectares. As of 2007, about 60% of this potential was realized through irrigation network or natural flow of Indian rivers, lakes and adoption of pumps to pull ground water for irrigation.
  80% of the water India receives through its annual rains and surface water flow, happens over a 4-month period – June through September. This spatial and time variance in availability of natural water versus year-round demand for irrigation, drinking and industrial water creates a demand-supply gap, that only worsens with Indias rising population. Proponents claim the answers to Indias water problem is to conserve the abundant monsoon water bounty, store it in reservoirs, and use this water in areas which have occasional inadequate rainfall, or are known to be drought-prone or in those times of the year when water supplies become scarce.