Determination of Shallow Groundwater Aquifer Geometry using Geo-Electrical Techniques in the Atankwidi Sub-Basin of the White Volta Basin, Ghana

Abstract

This paper presents the research findings on the delineation of shallow groundwater aquifer geometry in Atankwidi sub-basin of the White Volta Basin. The potential use of shallow groundwater for small-scale dry season irrigation is a key issue for irrigation development in the arid zone of Ghana. Farmers within the Atankwidi sub-basin of the White Volta Basin are increasingly adopting groundwater as a source of irrigation water due to the unavailability of surface water during the dry season. There is therefore the need to determine the shallow groundwater aquifer geometry in order to ensure sustainability in the application and possible expansion of groundwater irrigation in the area. The geometry of aquifer system in the Atankwidi sub-basin has therefore been delineated using geophysical (VES and EM) techniques. The depth to water table in the sub-basin ranged from 0.4 - 7.8 m with a mean of 1.7 m whiles the depth to bedrock varied from 2 - 38.3 m with a mean depth of 8.4 m. The mean saturation thickness of the aquifer system is 6.3 m with a minimum and maximum thickness of 0.1 m and 35.0 m respectively. The estimated potential volume of groundwater storage of the aquifer system in the sub-basin is 370,777,191.2 m³.

Keywords: Shallow Groundwater Irrigation; Aquifer geometry; Shallow well