Hydro geophysical Investigation for groundwater development at Gbongudu Area, Akobo Ojurin, Ibadan, Southwestern Nigeria

G.O. Layade,J.A. Adegoke,F.C. Oladewa

doi:10.4314/jasem.v21i3.14

G.O. Layade, J.A. Adegoke + Show 1 more

Open Access

https://doi.org/10.4314/jasem.v21i3.14

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Abstract

This paper presents the geophysical investigation for groundwater at Gbongudu area, Akobo Ojurin, Ibadan, Southwestern Nigeria. The area is underlain by the crystalline basement complex rocks and accessibility to potable water especially in the dry period of the year has been a major challenge. The Vertical Electrical Sounding using the Schlumberger configuration was employed. Twelve (12) vertical electrical sounding points were established in order to delineate the geo-electric layers in the area as well as evaluate the groundwater potential. The results are presented as profiles, geologic sections, curves, and maps. The VES results revealed a maximum of five geo-electric layers, viz: topsoil/lateritic sand, shale/clay, weathered layer, fractured basement and fresh basement respectively. Geo-electric sounding results were critically analyzed and interpreted. The yields of wells dug in most of these locations may be insufficient, even for domestic use because of its relatively small thicknesses. However, at a depth of 9.1 m a fracture zone occurs in VES 6 with resistivity value of 17.8 Ωm suggesting the presence of groundwater. Groundwater potential in this area is low on the average with VES 6 and VES 7 considered to be the main aquifer units suitable for groundwater exploration. Keywords: basement complex, electrical sounding, groundwater, exploration, aquifers

Highlights

Fresh water is a valuable resource for human needs and of fundamental importance to human life, animals and plants (Travassos and Menezes, 2004), it is of equal importance with the air we breathe in maintaining the virtual process to life and it makes up about 60% of body weight in human beings
The use of very low frequency electromagnetic (VLF-EM) and vertical electrical sounding (VES) for groundwater exploration is popular in the basement complex rocks terrains (Palacky et al, 1981)
The area falls under the Basement Complex area of Oyo state within the southwestern part of the reactivated basement complex of Nigeria and is underlain by the crystalline basement complex which wholly belong to the Pre-Cambrian - Cambrian potentials positively (Rahman et al, 1988)

Summary

Introduction

Fresh water is a valuable resource for human needs and of fundamental importance to human life, animals and plants (Travassos and Menezes, 2004), it is of equal importance with the air we breathe in maintaining the virtual process to life and it makes up about 60% of body weight in human beings. Electrical resistivity technique is an effective tool in delineating areas of good potential for groundwater development (Onimisi et al, 2013). The use of very low frequency electromagnetic (VLF-EM) and vertical electrical sounding (VES) for groundwater exploration is popular in the basement complex rocks terrains (Palacky et al, 1981). The vertical electrical sounding (VES) is a geophysical tool for the determination of subsurface geology of a place. It has been used extensively for the determination of the aquifer potential in the drilling of boreholes (Igboekwe, 2005; Igboekwe et al, 2006). The study area is accessible through networks of roads as shown in figure 1

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