Hydrogeophysical Investigation of Aquifer Layers in Nkporo, Ohafia Local Government Area

Abstract

Drilling a borehole in Nkporo area of Ohafia in Abia state without proper investigation may lead to wasting resources if water bearing formation is not achieved. This is because borehole drilling is very expensive. It is therefore necessary to carry out proper hydro-geophysical investigation in order to identify a good aquifer before borehole drilling. Electrical resistivity method has been chosen for the investigation of the water bearing formation. The use of Schlumberger array (Vertical Electrical Sounding (VES)) method of electrical resistivity was chosen based on the geology of the study area. This method was chosen because not only will it delineate the layers of the near surface aquifer but will also determine the thickness and depth to the aquifer. Five (5) vertical electrical soundings data were obtained from five (5) locations in the community using the Schlumberger array method. The investigations reveal that the area is mostly underlain shale. The formations are poor in aquifer materials. Borehole therefore, in the area should be drilled deep to depths ranging between 700 – 900m into sandstone as revealed in VES 3 and VES 4.