Integrated Geophysical Survey for Siting Boreholes in a Water-Stressed Rural Community in Yobe State, North East Nigeria

Communities in Yobe State face chronic water stress due to declining rainfall, limited hydrogeological knowledge, and a high rate of borehole failure attributable to poorly sited installations. This study integrates vertical electrical sounding and horizontal resistivity profiling to provide data-driven borehole siting recommendations for Nangere Local Government Area. Sixteen VES stations and three 600-metre horizontal profiles using the Schlumberger and Wenner arrays respectively were acquired across a 12-square-kilometre area characterised by crystalline basement overlain by variable thicknesses of Quaternary sediment. VES data were inverted using partial curve matching and computer-aided forward modelling to produce layer models at each station. Horizontal profiles resolved lateral variations in the weathered zone, identifying a NW-SE trending fractured zone of elevated porosity. Geoelectric parameters, including longitudinal conductance, transverse resistance, and reflection coefficient, were derived for each sounding station to evaluate aquifer protective capacity and productive potential. Five priority borehole sites were identified where the convergence of deep weathering, fracture zone intersection, and moderate overburden protective capacity optimises the probability of success. The study contributes to the evidence base for water resource planning in Yobe State and provides a replicable methodology for similar hydrogeophysical investigations across the semi-arid North East. Keywords: VES, borehole siting, Yobe State, hydrogeophysics, fractured basement