Identification of potential artificial groundwater recharge sites in an alluvial setting: A coupled electrical resistivity tomography and sediment characterization study

Alluvial aquifers are one of the most exploited and easily accessible aquifer networks across the world, as they coincide with regions of intensive human settlements. Over the years, improper management and overexploitation of groundwater has severely stressed the natural replenishing capacity of these aquifer systems. Identification of potential artificial recharge networks and their monitoring are urgently needed for long-term sustainable groundwater management. In this study, an efficient and cost-effective strategy to locate prospective groundwater recharge zones is devised by integrating electrical resistivity tomography (ERT), sediment characterization, and temporal monitoring techniques. The efficacy of the above strategy is evaluated in the central part of Indo-Gangetic basin (IGB). Correlation of 2-D ERT models with borehole lithology and depth-wise variation of hydraulic parameters deciphered the existence of prospective regions composed of highly permeable strata within ∼6–48 m depth. In addition, the behavior of the delineated prospective regions was monitored by applying time-lapse ERT study. The comparison of time-lapse 2-D ERT models highlighted a significant reduction in post-monsoon resistivity profiles, suggesting an increase in saturation levels due to infiltration of rainwater. This study provides an integrated cost-effective approach for identification of prospective artificial recharge sites and monitoring their efficacy in replenishing shallow aquifers, thereby enabling sustainable groundwater management.