Borehole Productivity Controlling Factors in Crystalline Bedrock Aquifer of Gkêkê Region, Center of Côte d’Ivoire

Abstract

The presence of both weathered rocks and fractured crystalline bedrock aquifers makes Hydrogeology in Gbêkê region of Côte d’Ivoire. Access to water in this region is not easy. This study focuses on the influence of borehole depth, weathering thickness and electrical resistivity of the geological structures on borehole productivity that exploit the crystalline aquifer system. Bivariate analysis was used to determine the relationships between these factors and specific capacity for measuring borehole productivity. The values ranged from 0.0088 to 2.20 m 3 ∙h −1 ∙m −1 . The analysis shows that there is no correlation between productivity and weathering thickness. However, weathering depths between 15 and 35 m provide the highest specific capacity values (Qs ≥ 1 m 3 ∙h −1 ∙m −1 ). For hydrogeological discontinuities interest, boreholes located in KH, QH and H anomaly curve types were the most productive. As productivity diminishes with depth, a deeper borehole can be more productive if it reaches a geological structure that is favorable for groundwater flow. Those hydrogeological parameters are extremely important in borehole productivity in Gbêkê region.