Geophysical Investigation for Groundwater Borehole Location at All Souls Grammar School, Ado Ekiti

ABSTRACT This project presents a geophysical investigation for groundwater borehole location at All Souls Grammar School, Ado-Ekiti, aimed at identifying suitable sites for sustainable groundwater development. The study employed the electrical resistivity method, specifically the Vertical Electrical Sounding (VES) technique, using the Schlumberger configuration. A total of several VES points were established within the study area to delineate subsurface layers and determine the most promising aquifer zones. The interpreted geoelectric sections revealed distinct layers comprising topsoil, lateritic sand, weathered basement, and fresh basement rock. The weathered and fractured basement zones were identified as potential aquifer units due to their relatively low resistivity and appreciable thickness, indicating high groundwater potential. Based on the results, the most suitable location for drilling the borehole was recommended at the VES point with the highest aquifer thickness and moderate resistivity values, suggesting good groundwater yield and quality. This investigation demonstrates the effectiveness of geophysical methods in groundwater exploration, particularly in basement complex terrains like Ado-Ekiti. The results provide a scientific basis for siting boreholes, thereby reducing the risk of drilling abortive wells and ensuring reliable water supply for the school community. Keywords: Geophysical investigation, Electrical resistivity, Groundwater exploration, Vertical electrical sounding, Borehole siting.