GEOELECTRICAL ASSESSMENT OF AQUIFER POTENTIALS AND ITS VULNERABILITY TO CONTAMINANT AT EL-AMIN PROPOSED UNIVERSITY SITE, MINNA, NIGER STATE, NIGERIA

Abstract

Vertical Electrical Sounding (VES) survey was carried out at El-Amin proposed University site, located along Eastern bye pass Minna, Niger State, Nigeria. It lies in the basement complex region of Northern Nigeria. The survey was carried out with the aim of determine the ground water potentials of the area and evaluate its aquifer protective capacity. The technique employed was the Vertical Electrical Sounding (VES) using Schlumberger array. A total of 48 VES points were sounded on grid profiles separated by 100 m apart with VES spacing of 100 m. Three to four layers were observed . The stratigraphy of subsurface shows : topsoil with resistivity range from 0.4 to 277.89 Ωm weathered/fracture basement layer having resistivity vary between 31.0 and 982.89 Ωm and fresh basement with resistivity range from 19.1 to 79935.239 Ωm. The weathered/fractured layer was considered as aquferous horizon. The longitudinal conductance and resistivity contour maps were produced. Thirteen VES points were delineated as ground water potential with resistivity ranging from 45.5 Ωm to 611.77 Ωm, thickness ranging between 3.5 m and 13.07 m and depth ranging from 8.8 m to 24.43 m which represent about 18.75 percent of the area. The south, south-east and north-west portions of the area are underlain by materials of moderate to good protective capacity while the western and central part of the area with thin over burden coincided with weak to poor protective capacity which expose the ground water in the area to pollution.