EVALUATION Of GROUNDWATER VULNERABILITY IN FRACTURED AQUIFER USING GEOELECTRIC LAYER SUSCEPTIBILITY INDEX AT OJU, SOUTHERN BENUE TROUGH NIGERIA

M O Eyankware,P.N Obasi,O M Nweke,A O I Selemo

doi:10.26480/gbr.02.2020.63.67

Abstract

A combination of geoelectric and hydrogeologic concept was used in the assessment of groundwater vulnerability in fractured aquifers of Oju and environs. The study area is underlain by the sediments of the Asu River Group, Southern Benue Trough Nigeria. A total of twenty-seven (27) Vertical Electrical Sounding (VES) was carried out within the study area. Geoelectric parameters (layer, resistivity and thickness) of the overlying layers across the study area were determined and used to evaluate the vulnerability of the underlying aquifers. Three charts were compared using geo-electrically derived models; LC (Longitudinal Conductance), GLSI (geoelectric layer susceptibility indexing) and GOD (groundwater occurrence, overlying lithology and depth to the aquifer. Results obtained from LC revealed that the study area fell within the moderate category, GLSI showed that aquifer vulnerability were categorize within negligible to low category and GOD fell within low to moderate category. On the average, groundwater within the study area is considered moderate vulnerable to groundwater contamination.

Highlights

Aquifer vulnerability as an integral part of the hydrological system is gaining more attention globally, due to increase in anthropogenic activities that pose threat to groundwater contamination/pollution
Electrical resistivity method involving vertical electrical sounding (VES) using Schlumberger configuration was successfully applied in aquifer vulnerability assessment of Oju, Southern Benue Nigeria
Geoelectric parameters obtained from the VES assists in the production of the vulnerability index maps

Summary

Introduction

Aquifer vulnerability as an integral part of the hydrological system is gaining more attention globally, due to increase in anthropogenic activities that pose threat to groundwater contamination/pollution. In hydrogeology, stated that aquifer vulnerability describes the comparative assessment of the potential exposure of groundwater as a result of anthropogenic activities to contamination (Thirumalaivasan et al, 2003). Various authors have integrated GOD, GLSI and Longitudinal conductance method in evaluation of groundwater vulnerability (Huan, et al, 2012; Khemiri, et al, 2013; Eyankware, et al, 2020; Saha, et al, 2011). A group of researchers pointed out that the assessment of water resource vulnerability to pollution helps to determine the proneness of groundwater contamination and essential for managing and preserving the groundwater quality (Huan et al, 2012). This work will be a vital tool to water sanitation and supply agencies as well as environmental management departments

Methods

Results

Conclusion