Mitigating the potential unintended impacts of water harvesting
Different forms of water harvesting have been used successfully in semi-arid areas of India for millennia as a means of protecting domestic water supplies and increasing or stabilising agricultural production. In recent years, water harvesting both in field (e.g. contour bunding) and along drainage lines (e.g. check dams) has been promoted and funded on a massive scale as part of different government and non-government programmes. Accepted wisdom is that rainfall should as far as possible be harvested where it falls and that these technologies are totally benign. However, evidence is emerging that water harvesting in semi-arid areas, if used inappropriately, can lead to inequitable access to water resources and, in the extreme, to unreliable drinking water supplies. Water balance studies in Andhra Pradesh and Karnataka have shown that water harvesting programmes impact significantly on patterns of water use and that this can result in distinct winners and losers. Winners include people who have improved access to water for productive purposes (e.g. irrigated agriculture) and losers include people whose access to water for domestic, productive and other purposes is reduced. It is also clear that livelihood gains experienced by some “winners” can dissipate as competition for water resources increases and traditional drought coping strategies become less viable and/or increasingly expensive. The recommendation from the analysis presented here is that water harvesting should be encouraged but within an integrated or adaptive water resources management framework using procedures that weigh up the benefits and tradeoffs associated with altered patterns of water use. The aim being identify potential unintended impacts so that, if at all possible they are avoided altogether, but if these do occur, they are recognised at an early stage and steps are taken to mitigate their affects.
Paper presented at the IWRA International Regional Symposium ‘Water for Human Survival’, 26-29th November, 2002, Hotel Taj Palace, New Delhi, India. 9 pp.