ABSTRACT
In Otuo Community, Owan East Local Government Area, Edo State, Southern Nigeria, a geoelectrical research was conducted to determine the most reliable aquifer bearing zone as well as the lateral and vertical variation of subsurface lithology with depth and distance, respectively. The Schlumberger electrode arrangement was used in this investigation to collect VES data in the field. In the research area, four VES stations were in use. Dar-Zarrouk parameters were used to characterise the aquifer in order to calculate the capacity bearing rating and groundwater potential of the region: resistivity contrast (RC), resistivity reflection coefficient (RRC), total transverse resistance (T), and total longitudinal conductance (S). The data revealed that, out of all the VES locations, VES 3 (coordinates N7o 12'5'', E6o 0' 9'') with eight layers is the most promising source of groundwater. While VES 1, 2, and 4 have values of 4787.22, 4003.95, and 28106.1005 (ohm-m2), respectively, they have the highest Total Traverse Resistance value of 73,050.27 Ωm2 (indicating a very good transmissivity of the layer), Resistivity Reflection Coefficient (0.500), and all parameters falling within good prospect for groundwater development. But VES 3 Total Longitudinal Conductance (S) value of 0.2842 mho indicates that it is not very effective in protecting aquifers. With VES 1, 2, and 4 having values of 22.02m, 27.34m, and 48.91m, respectively, the results also demonstrate that VES 3 had the maximum fracture thickness of 61.26 m, indicating that it has the biggest groundwater potential. In conclusion, the Schlumberger Array geo-electrical resistivity survey at Otuo yielded data that showed the most reliable aquifer carrying zone as well as the lateral and vertical change of subsurface lithology with depth and distance, respectively.
