Groundwater potential mapping of the basement complex terrain of Ekiti State, Nigeria

An integrated geospatial and geophysical approach was employed to characterize groundwater potential in a typical Basement complex terrain of Ekiti State, Nigeria. Geospatial datasets, including aeromagnetic, remote sensing, geological, and soil data, were combined with vertical electrical sounding (VES) measurements to generate 13 thematic layers that influence groundwater occurrence. Aeromagnetic filtering and processing identified subsurface fractures and lineament densities, while Shuttle Radar Topography Mission (SRTM) DEM and Landsat imagery were used to derive slope, elevation, drainage density, topographic wetness index, curvature, geomorphology, and land use/land cover (LULC). Lithology and soil maps were digitized and integrated, while transmissivity was derived from 150 VES points. Analytical Hierarchy Process (AHP) was applied to assign weights to these factors, and the weighted overlay analysis in GIS produced a groundwater favorability map. The area was classified into very low, low, moderate, and high groundwater potential zones, with moderate potential being the predominant category. Validation using borehole yield data from fifteen locations revealed an overall accuracy of 73%, confirming the model’s reliability. The results highlight the southwestern and northwestern flanks, particularly around Ilawe-Ekiti and Iyin-Ekiti, as the most promising zones for groundwater development. This framework demonstrates the utility of multi-criteria decision analysis and geospatial integration for sustainable groundwater assessment in Basement terrains.