Groundwater potentiality in hard-rock terrain of southern Saudi Arabia using electrical resistivity tomography approach

Abstract

To detect groundwater-bearing zones in southern Saudi Arabia, 10 profiles of 2D electrical have been constructed resistivity tomography at five selected sites. The collected data were corrected and processed using the RES2DINV software. The results demonstrated that site-1 contains two groundwater-bearing zones; the first zone is situated 13 m beneath the ground surface, while the depth of the second zone varies from 4 m to 15 m. A promising 15-m-deep groundwater-bearing zone was identified at site 2. The groundwater-bearing zones exhibit depths of 40, 10, and 10 m at sites 3, 4, and 5, respectively. The detected groundwater-bearing zones are notably shallow, with a depth of 20 m below the ground surface and with lateral extension up to 200 m. These aquifers prevail in the alluvial deposits, where the weathered/ fractured or fresh basement rocks underlying these aquifers. Moreover, rainfall recharges these unconfined aquifers, as evidenced by the increasing water levels along the main Wadi channels flow during rainy seasons. Sites 2, 3, and 5 are considered as groundwater-bearing sources with high potential. Because this unconfined aquifer can be swiftly replenished by the 300–360 mm of annual rainfall in the southern Saudi lowlands, it is a promising area for groundwater supply for future urbanization plans and agricultural projects in neighboring areas.