Resistivity Survey for Ground water at the School of Physical Science, Federal University of Technology, Minna Niger State

Abstract

Geoelectrical Investigation was carried out to evaluate the viability and to determine the subsurface lithology, depth to bedrocks for ground water potential at the School of Physical Science, Federal University of Technology, Gidan Kwano Campus Minna, Niger State, Nigeria. The area is located at the Basement Complex of Nigeria which comprises of Migmatites-Gneiss Complex, the Schist Belt, the older granites and unreformed acidic/basic dykes. Vertical Electrical Sounding (VES) Surveys were conducted using a resistivity meter along six (6) profiles at 100 m interval from each sounding point and a total of 36 VES measurement were made. Schlumberger electrode configuration was adopted with maximum current electrode spacing (AB/2) of 100 m. The results of the VES is made up of three (3) distinctive lithologies; the first layer is Top Soil/Lateritic Particles with resistivity value between 4.8 and 147.5 Ωm its thickness is between 0.2 m and 1.3 m. The second layer is a weathered/fractured basement with resistivity values between 22.9 to 5457 Ωm its thickness ranges between 0.7 m to 36.3 m and the third layer is fresh basement with resistivity values from 22.1 and 43665 Ωm. The stimulated result from the field data shows 3-4 layers resistivity model. The layers are characterised by A, H, K, HA and KH curve types. The area was categorised into high, medium and low groundwater potential zones. Borehole should be drilled on the following VES points; A1, A3, B3, B4, C1, C2, D2, D3, E3, E4, F2 and F1, these VES points depicts zones of good fractures.