Anisotropy and Characterization of Aquifer Geometry by Electrical Resistivity Tomography in Togoniéré (Department of Ferkessédougou, North of Côte d’Ivoire)

Abstract

Côte d’Ivoire is made up of more than 97% bedrock. The majority of water resources are contained in the fractured bedrock, where drilling has a high failure rate. It is therefore important to better understand these water reservoirs, as their hydrogeological significance is considerable. This study is conducted from this perspective and covers the sub-prefecture of Togoniéré (North of Côte d’Ivoire) where the water problem is acute. Its objective is to characterize the geometry of the aquifers in the sub-prefecture by using electrical resistivity tomography. The results highlight an anisotropy of the underground formations, more pronounced with depth, represented by a succession of resistant-conductive-resistant terrains. They reveal conductive formations interpreted as lateritic aquifers, located between 20 and 75 m deep and generally with thicknesses of 30 to 50 m. They have a triangular shape and lateral extensions of about 85 m. Other conductive formations (3 to 10 m), which have a NW-SE and NE-SW dip and a 45˚ inclination, suggest a network of fractures facilitating the infiltration and storage of water. Their reach does not exceed 85 m but can extend to 185 m in length. These aquifers result from regional tectonics or local alteration.