Analysis of Electrical Resistivity Survey Data for Aquifer Potential and Protective Capacity at Mararaba Dan-Daudu Minna, North Central Nigeria

Abstract

It is a fact that basement complex regions lacks sufficient overburden that can host sustainable water table, water bearing fractured/weathered rocks referred to as aquifers are usually identified via suitable geophysical methods to proffer solution to water challenges within these regions. This current study targets the exploration of groundwater potential within the Mararaba Dan-daudu community, a suburb of Minna metropolis. Electrical resistivity method was employed to delineate aquifer prospects and their protective capacity within the area of study. The data from thirty-six Vertical Electrical Sounding (VES) survey points were acquired and analysed. Survey points were aligned along six profiles (A – F) with six VES points per profile. Interpretation of VES points along profiles was helpful in determining the number of layers and thickness. The analysis revealed mainly three layers comprising of sand and fresh laterite at the first layer, fractured/weathered basement at the second layer and fresh basement at the third layer. Iso-resistivity mapping was also done at various depths (surface, 5 m, 10 m, 15 m, 20 m, 30 m and 40 m) respectively to investigate the lateral variations of resistivity over a horizontal plane. These showcased the electrical conductance sliced at the depths of interest. Thirteen VES points (A1, A5, A6, B1, B3, B6, C6, D6, E6, F1, F2, F4 and F5) were mapped as having good prospective aquifer properties. Longitudinal conductance was computed for the outlined VES points to determine their Aquifer Protective Capacity (APC). The result of (APC) rating for the 13 VES revealed the frequency and percentage of APC ranged as: 2 VES locations (15.4%) have good APC, 8 VES locations (61.5%) have moderate APC and 3 VES location (23.1%) have weak APC. with only 3 VES locations out of 13 VES locations in the study area revealed weak APC, the results proved that the groundwater potential of the study area has moderately good APC.