Groundwater potential and aquifer characterization within Unilorin campus, Ilorin, Southwestern Nigeria, using integrated electrical parameters

Electrical resistivity investigation was carried out at different sections of University of Ilorin main campus, Ilorin Southwestern Nigeria with the aim of evaluating groundwater potential and properties of the aquifers. Data were acquired at different locations using vertical electrical sounding (VES) method. Hydraulic conductivity, transmissivity, transverse unit resistance, longitudinal conductance, fracture contrast and reflection coefficient were estimated and used for evaluating the groundwater potential and aquifer vulnerability. The results revealed three–five geo-electric layers which correspond to the top soil, lateritic layer, weathered rock layer, fractured rock layer and the fresh basement rock. The top soil has apparent resistivity values ranging from 72.0 to 8117.3 Ωm and thickness range of 0.4–1.6 m while the last geo-electric layer is the infinite fresh basement having apparent resistivity greater than 300 Ωm. The VES curve types obtained are KH, H, A, AKH, HKH and HA with the H curve type covering about 50% of the study area. Aquifers in most part of the study areas are prone to contamination because of low protective capacity of the overburden material. Low groundwater potential covers about 56.79% of the total area and limited to northwestern corner, parts of the north, southwest and northeast. High potential for groundwater was observed at the eastern, northern and southern part of the study area covering about 12.35%. All areas that have thick overburden, high transmissivity, low fracture contrast and reflection coefficient are characterized by intense fracture. These areas are recommended for exploration for water at optimum yield.