RAINWATER HARVESTING RECHARGE AUGMENTATIONTHROUGH PERCOLATIONTANKS IN SEMI- ARID BASALTICTERRAIN IN WESTERN INDIA

摘要

Augmentation of recharge to ground water through percolation tanks is closely related to the survival of about 15rnmillion farmers and an equal number of cattle, living in the semi-arid basaltic plateau in western India. Here the Monsoon rains arernrestricted to a few rainy days between June and September. It is therefore, necessary to harvest the monsoon runoff into smallrnpercolation Tanks in mini- catchments, by constructing earthen bunds on small streams and allowing the stored water in the Tanks tornpercolate and recharge the ground water body. The residence time of water in the mini-catchments is thus increased and it is possiblernfor the farmers to dig wells and give supportive irrigation to the crops in their small farm plots. The efficiency of the percolationrnTanks is hampered by the silt, which accumulates in the tank bed, year after year. It is therefore, necessary for the beneficiaryrnfarmers to remove silt the tank bed when the tank dries in the summer season. Soil conservation practices should also be followed inrnthe watershed of a percolation tank in order to reduce the silt coming into the tank. NGOs have an important role to play in thisrnfield. Recharge augmentation through watershed management & construction of percolation tanks is one of the ‘best practices’rnincluded in the UNESCO-IGCP Project no.523: GROWNET, for which the Author is Project Leader.