Vertical Electrical Sounding Survey for Groundwater Exploration in Parts of Anyigba and its Environs, in the Anambra Basin of Nigeria

Abstract

Aim: The aim of the study is to delineate the subsurface geologic layers and evaluate the aquifer potential in Anyigba and its environs. Study Design: The resistivity sounding surveys were carried out randomly within the study area with half of the total surveys carried out within Anyigba town. Lithologic logging of boreholes close to the survey lo\ations were also carried out. Place and Duration of Study: The study area is Anyigba and its environs in Kogi state, central Nigeria. Field geophysical resistivity survey and borehole lithologic logging of the study area were carried out between March 2010 and December 2012. Methodology: The field resistivity sounding surveys were carried out with an ABEM SAS (1000) Terrameter using the Schlumberger electrode array. Drill cuttings from boreholes sampled at 3 meters interval were used for the identification of the subsurface lithology. Results: The results of the study reveal the presence of four to six geologic layers within the study area. The geologic layers and the mean thicknesses of the layers are: i. Lateritic top soil (1.022m), ii. Lateritic sandy layer (5.285m), iii unsaturated loosely compacted sandstone layer (9.843m), iv. unsaturated compact sandstone layer (45.8m), v. partly saturated sandstone layer (26.9) and vi. A fully saturated sandstone layer. Conclusion: Four to six geologic layers have been delineated within the study area. The fifth (partly saturated sandstone) layer and the sixth (fully saturated sandstone) layer constitute the main aquifer units in the study area.