Rainwater Harvesting & Recharge Augmentation Through Percolation Tanks in Semi-Arid Basaltic Terrain in Western India (A best practice identified under GROWNET. UNESCO-IGCP Project no. 523)

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