Event-Based Analysis of Recharge Dynamics in a Heterogeneous Hard-Rock Catchment using Hydrogeophysical Techniques

Understanding recharge processes in heterogeneous hard-rock terrains is essential for sustainable groundwater management. This study examines the spatiotemporal recharge dynamics of a 2 km² experimental micro-catchment in Rajasthan, India, using integrated hydrometeorological observations, Direct Current resistivity and Induced Polarization (DC–IP) imaging, Normalized Difference Vegetation Index (NDVI) time series, and aquifer tests. NDVI provided seasonal moisture variability, while ten DC–IP profiles delineated subsurface architecture and structural controls on flow.Geophysical sections reveal a highly heterogeneous system dominated by massive high-resistivity sandstone blocks (>200 Ω·m) intersected by vertical to sub-vertical low-resistivity fracture zones (