Importance of sustainable management of percolation lakes in semiarid basaltic terrain in western India
Sustainable management of percolation lakes or percolation tanks is closely related to the survival of approximately 15 million farmers and an equal number of cattle living in the semiarid basaltic plateau of western India. Here, the monsoonal rains are restricted to a few rainy days between June and September. It is therefore necessary to harvest the monsoon runoff into small percolation lakes in mini-catchments by constructing earthen bunds on small streams and allowing the stored water in the lakes to percolate and recharge the groundwater body. The residence time of water in the mini-catchments is thus increased and it is possible for the farmers to dig wells and irrigate the crops in their small farm plots. The efficiency of the percolation lakes is hampered by silt that accumulates in the lake bed or tank bed, year after year. It is therefore necessary for the beneficiary farmers to desilt the lakebed when the lake dries in the summer. Soil conservation practices should be followed in the catchment area in order to reduce the amount of silt entering the lake. Non-governmental organizations play an important role in this field.