GEOELECTRICAL INVESTIGATION FOR GROUNDWATER AT DAY SECONDARY SCHOOL, KAMPALA, MINNA, NIGER STATE, NIGERIA

Abstract

Geoelectrical investigation of groundwater has been carried out at Day Secondary School, Kampala, Minna, Niger state, Nigeria. The area is situated on Latitude 9⁰40'37.11'' to 9⁰41'37.1''N and longitude 6⁰29'52.64'' to 6⁰30'51.56'' E. The survey was carried out with the aim of delineating the potential area for groundwater development and locating possible and suitable sites for productive boreholes, via overburden thickness and depth to the groundwater within the study area. A total of 500 m x 500 m was covered with VES points at 100 m interval and inter profile space of 100 m giving a total of thirty six (36) VES points. The schlumberger configuration was used for data collection with half-current electrode (AB/2) ranging from 1 to 100 m. WinResist computer software package was used to produce the VES curves. The quantitative interpretation of the VES curves made use of curve matching and computer aided approach. The depth sounding interpretation results were used to generate geoelectric section. The corresponding geologic section were also generated which revealed the existence of three subsurface layers. These layers comprises the topsoil, weathered/fractured basement and fresh basement The depth to basement map was also produced to further indicate depth to basement from the ground surface with VES A2, B5, D2 and E1 to be relatively deeper with depth values range between 25 to 35 m while the shallower region of the area has a depth range values between 10 to 20 m. Hence, VES A2, A5, B4, B5, C2, C4, D4, D5, E1, E3, and F4 are high conductive zone which are prolific for ground water potential. The depth range of the aquifer potential zones is between 22.7 m to 50.4 m. Correlations of the geologic sections extracted from the geoelectric section with the interpreted nearby borehole log were in agreement.