Abstract:
Groundwater Potential and Aquifer Vulnerability of the North-Western part of Akure, Nigeria was
investigated using Electrical Resistivity Method, involving vertical electrical sounding. The
research was carried out with the aim of delineating the Groundwater Potential and Aquifer
Vulnerability of the area. Geology and elevation maps were obtained from the existing geology and
topographic map of the area. Two hundred and twenty four (224) VES was carried out using
Schlumberger array technique. The VES data were interpreted qualitatitively and quantitatively
using a partial curve matching from which aquifer layers, resistivity and thickness values and the
overlying layers, resistivity and thickness and bedrock relief values were obtained. The additive
model was modelled using surfer software and the model was utilized for this study both for the
groundwater potential evaluation (GERRT) and aquifer vulnerability assessment (GERT). The
results delineated fifteen different curve types like KH, HA, H, A and AA across the area. Three to
five geo-electric layers were delineated across the area. The resistivity of the layers vary
respectively as 6.9 - 550 ohm-m, 60 - 2500 ohm-m, 20 - 650 ohm-m and 220 - 7900 ohm-m in the
topsoil, weathered layer, partially weathered basement/partially fractured basement and presumed
fresh basement and thickness values also vary respectively as 0.4 - 4.0 m, 0.7 - 19.0 m and 4.0 - 60
m. Geo-electric derived data and geomorphologic data were modeled and synthesized to generate
GERRT map of about 60% characterized as low groundwater potential, about 30% as moderate
potential and about 10% high potential and was validated with functional hand-dug wells and
boreholes in the area and also generated GRET map of about 60% characterised as high
vulnerability, about 35% as moderate and 5% as low vulnerable area. It was recommended that the
high and moderate groundwater potential zones should be accorded priority for any future
groundwater development effort in the study area and should be protected through grouting
