Identification of Suitable Recharge Sites by Integrated Hydro-geophysical Approach for Augmenting Groundwater in Reodar Block, District Sirohi, Rajasthan.

The dependence of human beings on groundwater and ever-increasing demands of growing population, agriculture and industries, has resulted in its over-exploitation. This has led to the decline of groundwater levels and its shortage especially in lean season. The study area, Reodar block of Sirohi district, Rajasthan, is an over-exploited block with the stage of groundwater extraction at 159% and has an average declining water level trend at the rate of 0.24 m/year. Artificial recharge was proposed in the study area through the construction of recharge shafts and injection wells, after delineating the weathered thickness in the submergence area of existing ponds and check dams of the study area by carrying out vertical electrical sounding (VES). In all, VES were conducted at 178 sites and recharge structures were constructed at 76 out of 109 scientifically selected sites with suitable weathered thickness and attempt was made to establish their impact on water levels through pre-monsoon water level monitoring. The comparison of pre-monsoon water level observations spanning over four decades reveals its spatio-temporal decline in the study area. The construction of these recharge structures has resulted in significant increase in area from 38% to 68%, under 0 to 20 m below ground level water level range. This study demonstrates the importance of resistivity surveys in scientifically selecting the suitable sites for construction of recharge structures and significance of long-term water level monitoring in assessing the groundwater scenario and impact assessment, in poorly characterized hydrogeological areas. [ABSTRACT FROM AUTHOR]