Efficacy of Percolation Ponds as Artificial Recharge Structures and the Controlling Factors

The hard rock aquifers of southern and western India, receive less than 10% precipitation as natural recharge, and are witnessing Over-Exploitation. Consequently measures are being adopted to augment groundwater resources artificially. Percolation ponds or tanks the most popular artificial recharge structures in India, are constructed across monsoon streams for the above purpose. However no detailed study was carried out to evaluate their performance in different hydrogeological environs. This paper reports the efficacy of percolation ponds, situated in different geological terrains evaluated using chloride mass balance method. Depending on the location of the percolation tanks, varied percolation fractions (of impounded water) were obtained, Basalts 0 20-0 30, Granite-Gneisses 0 30-0 45, and Sandstones 0 60, depending on the transimssion properties of rocks. In addition, soil characteristics and ambient hydrogeological regime of the area are important factors controlling the efficacy of a percolation tank.