Evaluation of Groundwater Potential in Gashua Northeast Nigeria, Using Electrical Resistivity Method

Abstract

Electrical resistivity method was used to evaluate the groundwater potential of Gashua, Northeast Nigeria. A total of ten (10) vertical electrical sounding (VES) using Schlumberger electrode configuration were carried out. The field data was interpreted using Winresist version 1. The results of the electrical resistivity survey indicated that the study area is composed of five geoelectrical layers namely; the topsoil (which is a mixture of sand and clay materials), clay, sand, sandy clay and sand. The resistivity of the first layer range from 42.7 to 199.7 Ωm and its thickness range from 0.6 to 1.9 m, the second layer had resistivity ranging from 16.5 to 37.9 Ωm with a thickness ranging from 4.1 to 10.7 m. The resistivity of the third layer ranged from 101.2 to 288.2 Ωm and the thickness ranged from 38.9 to 99.7 m, this was the first aquifer in the study area. The resistivity of the fourth layer ranged from 100.7 to 214.3 Ωm and its thickness from 28.5 to 94 m. The fifth layer is the second aquifer and its resistivity ranged from 254 to 350 Ωm. The aquifer resistivity ranged from 101.2 to 288.2 Ωm and from 253.8 to 350.1 Ωm for the first and second aquifers respectively. The study area is composed of two potential aquifers that are capable of producing groundwater, the first aquifer is unconfined and it highly susceptible to contamination. The second aquifer is confined and it is capable of yielding high volume and quality groundwater for both domestic and industrial consumption. It is advisable to drill boreholes in the study area to a depth beyond 120 m in order to have sustainable and quality groundwater supply for consumption