Characterization of Groundwater System Using Geology, Hydrogeology and Geophysical Methods in Federal University of Technology, Minna, Bosso Campus, North-Central, Nigeria

Abstract

The studies aimed at characterising the groundwater system of the Bosso campus of Federal University of Technology, Minna was carried out. Geology of the area was studied using a topographical map on a scale of 1:10,000. Hydrogeological studies were conducted on existing boreholes within the campus and new areas. 1D geophysical study was conducted using a Terrameter employing the Schlumberger array for the Vertical Electrical Sounding (VES). The geological mapping revealed presence of granitic rock with intrusion of quartz vein and joints, major jointing/fracturing is in the NE-SW direction. Geophysical data interpretation was done using computer aided iteration method which enabled the delineation of various geophysical layers in order to reveal the structural control of groundwater and aquifer system. The results show three predominant geoelectric layers: the topsoil, weathered/fractured granite and fresh granite. Apparent resistivity values of the first layer ranges from 14.1Qm-571.90m with thickness of 0.5m-4.6m, second layer has apparent resistivity values of 10.0Qm- 406.9Qm with thickness of 2.0m-13.1m and the third layer having apparent resistivity values ranges from 1467.6Qm-19031.2Qm with an infinite thickness. Isopach map with the resistivity maps at 10m and 30m respectively shows very low to low apparent resistivity values with thick overburden which can constitute zones of high groundwater potential at north-eastern and south-eastern parts of the study area. Hydraulic conductivity results range from.7.00*10’5 m/s to 4.31 xl O m/s. The result falls within standard range for fine grain to coarse grain sand of 2.00x1 O' m/s to 6.00 x 10 m/s. It is concluded that the north central parts f the study area have poor to marginal groundwater potential while the north­ eastern and south-eastern part is supported by the occurrences and concentration of fractures which can constitute weathered/fractured aquifers around these regions.