Near-surface groundwater exploration using the geoelectrical resistivity method: A case study of Wadi Nisah, Riyadh, Saudi Arabia

Abstract

In desert regions like Saudi Arabia, groundwater exploration is critical for drinking, household, and agricultural purposes. The purpose of this study is to use Vertical Electric Sounding (VES) to assign near-surface groundwater sources in the Wadi Nisah area of central Saudi Arabia. Twenty VES stations were installed in the central part of Wadi Nisah, with a maximum half current electrode separation (AB/2) of 100 m, utilizing a Syscal R2 resistivity-meter with Schlumberger electrode design. The interpretation of these VES's revealed five geoelectric layers, the first of which is formed of dry sand with greater resistivity values and has a depth of around 3 m. The groundwater-bearing aquifer is represented by the fifth layer, which is the deepest, with depths ranging from 37.8 to 52.25 m below the surface and resistivities ranging from 47 Ω-m to 115.3 Ω-m. Six geoelectrical cross-sections were also mapped to show the lateral and vertical heterogeneities of the underlying lithology in the study area. These findings suggest that the groundwater bearing layer is a hydrologically promising zone capable of delivering optimal groundwater yield for drinking and agricultural use in the study area; the VES technique is a useful tool for identifying groundwater prospective zones.