Optimising Groundwater Exploration with Geospatial and Electrical Resistivity Methods within Crystalline Basement Terrain of Ajaokuta, Northcentral Nigeria

Groundwater plays a crucial role in sustaining livelihoods and ensuring a reliable water supply in regions with insufficient or unreliable surface water. The effective assessment and management of groundwater potential are essential for a sustainable water supply. Vertical Electrical Sounding (VES), was integrated with Multi-Criteria Decision Analysis (MCDA) through a Geographic Information System (GIS) to assess groundwater potential in Ajaokuta, Northcentral Nigeria. Geoelectric parameters such as aquifer thickness, aquifer resistivity, reflection coefficient and basement resistivity were used to characterise the subsurface lithology and aquifer structures. Similarly, various spatial themes such as geoelectric parameters, geology, lineament density, slope, drainage density, land use/land cover, and average annual rainfall were integrated within the GIS environment using MCDA of AHP to estimate the groundwater potential zones. Results indicate that drainage density is the most influential factor, followed by geology. The study was classified into four groundwater potential zones: high (0.42%), moderate (29.32%), low (64.55%), and very low (5.71%)—highlighting the spatial variability of groundwater availability within the study area. it was observed that areas underlain by the Lokoja-Bassange formation and quartzite exhibit excellent groundwater potential while areas dominated by the schist show moderate groundwater potential and areas underlain by migmatite, gneiss and granite exhibit moderate to low groundwater potential. The method proves effective in groundwater exploration and offers valuable information for proper groundwater management. The findings of this research contribute to the advancement of hydrogeophysics and geographic information science. The method can be adopted in similar geological and hydrogeological terrain.