Geohydraulic study of aquifer characteristics in parts of Enugu North Local Government Area of Enugu State using electrical resistivity soundings

Bethrand Ekwundu Oguama,Daniel Nnaemeka Obiora,Johnson Cletus Ibuot

doi:10.1007/s13201-020-01206-2

Abstract

Geophysical survey employing vertical electrical sounding (VES) was achieved in Enugu State College of Education (Technical). Schlumberger electrode configuration was used in acquiring the data which were interpreted using the WinResist software. Four to five geoelectric layers were delineated from the interpreted results. The hydraulic parameters (hydraulic conductivity, porosity, formation factor, tortuosity and transmissivity) were estimated from the values of resistivity and thickness which are primary geoelectric parameters. The result shows the hydraulic conductivity varying from 2.71 to 70.45 m/day, transmissivity: 49.2288–1127.944 m2/day, porosity: 33.71–49.44%, formation factor: 0.0014–0.0026 and tortuosity: 0.2667–0.2935. The zones with high and low values of these parameters were delineated. The potentiality of the aquifer units show moderate to high a reflection of the heterogeneity of the subsurface which is affected by the composition and geometry of the formation. The result from this study provides some important conclusions for future groundwater exploration and management.

Highlights

The subsurface characteristics are controlled by soil composition, dissolved ions, thickness and water contents
The study area is characterised by heterogeneous lithology with four to five geoelectric layers with resistivity values varying from low to high values
The hydraulic parameters were estimated from the primary aquifer geoelectric parameters and evaluated based on the results

Summary

Introduction

The subsurface characteristics are controlled by soil composition, dissolved ions, thickness and water contents. The increase in population and urbanisation has put a lot of pressure on subsurface structures as well as groundwater repositories. Enugu has witnessed an increased in population which has signal an increase in local economy, the inhabitants being farmers, civil servants, students, business men and women. They rely mostly on boreholes as a major renewable freshwater source, increasing the demand for potable water supply. In subsurface formations such as sedimentary or crystalline rocks, groundwater exists within

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