Aquifer potential zones within Akure, Nigeria, using geo-electrical derived parameters and GIS multi-criteria model approach

Abstract

This research addresses the recurring issue of water scarcity during dry seasons in Akure metropolis, Nigeria—a crisis exacerbated by demographic growth, increasing domestic and industrial water demands, and groundwater overexploitation. Through comprehensive geophysical investigations, we developed a methodological framework to identify and spatially delineate zones of groundwater resource prospect. Our approach integrated multiple hydrogeological parameters derived from electrical resistivity surveys (transverse resistance, hydraulic conductivity, and aquifer transmissivity) with lineament density analysis from satellite imagery to create thematic spatial representations. These parameters were systematically weighted using the Analytical Hierarchy Process (AHP) within a multi-criteria decision analysis framework to construct a groundwater prediction mapping index. The results from the iso-resistivity map of the saprolite layer revealed areas with clayey aquifers, fractured/clayey aquifers, sand/clayey sand aquifers. The isopach map of the saprolite layer shows areas with low, medium, and high groundwater yield. The depth to basement surface layer map revealed areas with bedrock swells and locations with bedrock troughs which will be suitable for groundwater exploration. The resulting groundwater potential prediction model classified the investigated site into four specific categories: low, low-medium, medium, and medium-high potential zones. The results show that nearly 92% of the metropolitan zones exhibit relatively low groundwater prospects, with only 8% demonstrating suitable characteristics for sustainable extraction. This research provides critical spatial intelligence for identifying viable groundwater development zones and serves as a guide for local water authority bodies to reduce borehole failures.