Water harvesting through watershed management in different agro-ecological regions of India

In India, per capita availablity of water is reducing exponentially due to increasing population pressures and has declined from 5 300 m(3) in 1955 to 1 700 m(3) in the year 2000 against the world's average of 7 400 m(3) and Asian average of 3 240 m(3). The rainfed area (about 63% of the total geographical area) contributes only 45% to the national food basket due to inadequate and highly erratic rainfall while 37% of the irrigated area accounts for 55% of the total food production. As the scope of expanding irrigation potential is limited, effective water harvesting and management practices coupled with appropriate dryland technology are essential to increase the present production level of 2 10 M tonnes to 300 M tonnes by 2020. The gap between water supply and demands necessitates harnessing of available water resources with efficient water conservation and management techniques. It has been amply demonstrated that participatory water resource development in watershed management programmes has singificantly increased foodgrain and biomass production and resulted in moderation of floods, mitigation of droughts, augmentation of water ground recharge, employment generation and improvement of socio-economic conditions of the local people. The water harvesting practices include in-situ water conservation, micro-catchments, and ex-situ water harvesting and storage systems. Rainwater harvesting technologies are highly location specific and practices evolved in a given agro-ecological region have limited applicability in other regions. Of the various factors affecting water harvesting technology, rainfall is most important parameter due to its erratic temporal and spatial variations. The water harvesting practices in various parts of the country can, therefore,be best described based on agro-ecological regions which are having homogeneity in bio-physical attributes of soil, climate, toipography and landuses. This paper briefly describes the status of water harvesting techniques following the concept of watershed management in different agro-ecological regions of the country.