Identification of hydrogeological and geoelectrical parameters influencing the productivity of boreholes in the commune of Daloa (Central-Western of Côte d'Ivoire).

This study was to determine the hydrogeological and geoelectrical parameters affecting the productivity of water boreholes in the Daloa commune. Using the Schlumberger configuration, we carried out 15 parallel and perpendicular electrical profiling and 40 Vertical Electrical Soundings (VES). We also performed Electrical Resistivity Tomography (ERT) with a pole-dipole configuration at one site. The data processing allowed the identification of the different layers of the subsurface and their geoelectric properties that influence the productivity of the boreholes in the study area. These geoelectric data have shown that the productivity of the boreholes is more related to the conductive anomalies (W and U) than to the vertical electrical sounding. The processing of the hydrogeological data has shown that borehole productivity in the study area using Self-Organising Map (SOM) is a function of the hydraulic conductivity but also the thickness and density of the fracturing. Sixteen new boreholes on the main campus of Jean Lorougnon Guede University, Daloa, validate these results. The yield of these productive boreholes varies between 7.5 and 22 m/h, with an average of 15.2 m/h, four times higher than the values usually obtained in the study area. The success rate of these boreholes is about 70 %. This study has shown how effectively integrating hydrogeological and geoelectrical parameters provides information on the lithology and structural conditions in the subsurface necessary for productive drilling.