Water resources of India

Water resources of a country constitute one of its vital assets. India receives annual precipitation of about 4000 km. The rainfall in India shows very high spatial and temporal variability and paradox of the situation is that Mousinram near Cherrapunji, which receives the highest rainfall in the world, also suffers from a shortage of water during the non-rainy season, almost every year. The total average annual flow per year for the Indian rivers is estimated as 1953 km. The total annual replenishable groundwater resources are assessed as 432 km. The annual utilizable surface water and groundwater resources of India are estimated as 690 km and 396 km per year, respectively. With rapid growing population and improving living standards the pressure on our water resources is increasing and per capita availability of water resources is reducing day by day. Due to spatial and temporal variability in precipitation the country faces the problem of flood and drought syndrome. Overexploitation of groundwater is leading to reduction of low flows in the rivers, declining of the groundwater resources, and salt water intrusion in aquifers of the coastal areas. Over canal-irrigation in some of the command areas has resulted in waterlogging and salinity. The quality of surface and groundwater resources is also deteriorating because of increasing pollutant loads from point and non-point sources. The climate change is expected to affect precipitation and water availability. So far, the data collection, processing, storage and dissemination have not received adequate attention. The efforts initiated under the Hydrology Project Phase-I and the development of the Decision Support System proposed under Hydrology Project Phase-II are expected to bridge some of the gaps between the developed advanced technologies of water resources planning, designing and management and their field applications. The paper presents availability and demands of water resources in India as well as describes the various issues and strategies for developing a holistic approach for sustainable development and management of the water resources of the country. It also highlights integration of the blue and green flows and concepts of virtual water transfer for sustainable management of the water resources for meeting the demands of the present, without compromising the needs of future generations.