Aquifers productivity in the Pan-African context

Abstract

In this study, 50 Vertical Electrical Soundings (VES) were carried out in the region, including 14 near existing boreholes for comparison. Aquifer parameters of hydraulic conductivity and transmissivity were obtained by analyzing pumping test data from existing boreholes. An empirical relationship between hydraulic conductivity (K) obtained from pumping test and both resistivity and thickness of the Pan-African aquifer has been established for these boreholes in order to calculate the geophysical hydraulic conductivity. The geoelectrical interpretation shows that almost all aquifers are made of the fractured portion of the granitic bedrock located at a depth ranging between 7 and 84 m. The hydraulic conductivity varies between 0.012 and 1.677 m/day, the resistivity between 3 and 825 Ωm, the thickness between 1 and 101 m, the transmissivity between 0.46 and 46.02 m2/day, the product Kσ between 2.1 × 10−4 and 4.2 × 10−4.