Delineation and prioritisation of groundwater recharge areas in the state of Tamil Nadu using geographical information system

Delineation and prioritisation of suitable areas for artificial groundwater recharging (AGR) in the state of Tamil Nadu was carried out in the present study. Soil properties namely, soil drainage and land capability class, and geology of the aquifer were identified as spatial parameters that influence the AGR. Weights of 25, 25, and 50% were given to the soil drainage, land capability class, and geology of the aquifer, respectively. Variability within a specific theme was considered by assigning appropriate score to the subtheme. The depth of water table, in addition to soil drainage and land capability class, and geology of the aquifer, was used to decide the priority area of the AGR. Prioritised areas were divided into different rainfall zones as priority first (PR1) and priority second (PR2), which was found to be 14.29% and 38.18% of total area of the state, respectively. Considering bi-modal nature of rainfall in Tamil Nadu, the estimated numbers of percolation pond and check dam were worked out as 6,118 and 15,730 for PR1 areas; while numbers of percolation pond and check dam were worked out as 16,468 and 42,350 for PR2 areas, respectively. The results of this study can help state departments to implement the AGR scheme.