Identification of high Groundwater Potential Locations in the Atebubu Municipality of Ghana using the Electrical Resistivity Method

The Atebubu municipality has been battling with a perennial potable water crisis for the past few decades. Borehole and well contractors in the municipality have been using nonscientific means to site aquifers prior to drilling, and this is the major cause of the high incidence of dry boreholes often recorded. Most of the hand-dug wells and boreholes are only productive during the raining season. This problem affects economic activities, children’s education and the quality of life of the people. This paper used the electrical resistivity method in the Wenner and gradient array configurations to access subsurface groundwater information leading to high yielding groundwater potential locations. The results show resistivity values for both Wenner and gradient techniques ranging from 5 to 2212 Ωm across the profiles. Resistivity distributions in the very low bracket, interpreted as clay contents, ranged from 5 to 210 Ωm and dominate the shallow subsurface to about 50 m. The thickness of this layer is approximated at 10 to 20 m. Moderately low resistivity distributions (from 100 to 506 Ωm) were observed at deeper depth with only few portions stretching to the middle belt. This bracket of the resistivity distribution is interpreted as water contents, while the high to very high values which are interpreted as competent rock formations were observed predominantly at both deeper depth and the middle belt. High yielding aquifers are therefore expected to be intercepted at deeper depths, overlain at most locations by a clayey vadose zone. Though results of the two measurement techniques significantly corroborated, the Wenner technique appears to suggest that more than half of the depth probed could be clay content, opposed to the gradient technique which portrays more fractured rocks, revealing better chances of high yielding groundwater potential at the sites identified. Keywords: Atebubu, yielding, groundwater, borehole, surface water