Evaluation of aquifer characteristics and groundwater protective capacity in Abavo, Nigeria

Abstract

Abstract Aquifer characteristics evaluation enables the determination of aquifer’s ability to recharge as well as discharge. However, knowledge of aquifer characteristics has been scarce in Abavo area. Thus, geophysical and hydrogeological investigations, involving vertical electrical sounding (VES), pumping test and well logging were conducted in Abavo area, Nigeria, to evaluate the aquifer hydraulic properties as well as the groundwater protective capacity of the area. Seventeen (17) VES, using the Schlumberger configuration, were carried out. The field data were curve – matched, iterated, using Win Resist software. The VES result revealed subsurface lithology that comprised lateritic top soil/sand, sandy clay/clayey sand, fine sand, medium sand and coarse to gravelly sand. The VES result equally revealed an aquifer depth range from 28.8–76.6 m, with resistivity range from 1175–27,272 Ωm. Two boreholes were drilled, the cuttings were collected and were used to model the subsurface lithology. Well logging result showed that the electrical conductivity (EC) as well as total dissolved solid (TDS) are 15 µs/cm and 112 mg/l respectively, indicative of the fact that the values were within the standard organization of Nigeria (SON) permissible limit for drinking water. Pumping test analysis, using the Cooper Jacob’s method, revealed that the transmissivity, specific capacity, storativity and hydraulic conductivity are 5.9m2/day, 33.13 m/day, 0.0069 and 0.1722 m/day respectively. The study revealed longitudinal conductance and transverse resistance range of 0.001048–0.027828 Ω-1 and 105470.4–1255775.3 Ωm2 respectively. These results have established that the aquifer is semi-confined, has poor protective capacity and high rechargibility and will provide adequate, potable groundwater for local water supply to communities for domestic and other purposes.