Hydrogeological Parameters Significantly Affecting the Productivity of Boreholes in the Bedrock Aquifer of the Bounkani Region, Northeastern Côte d'Ivoire

Abstract

Drilling involves mechanical surveys carried out directly above aquifers to capture groundwater that will be used to supply drinking water to populations and their activities. It is therefore important to understand the hydrogeological indicators responsible for the productivity of a well drilled into bedrock aquifers. This is the context for the present study, carried out in the Bounkani region (northeastern Côte d'Ivoire). It is in this context that the present study was conducted in the Bounkani region (northeastern Côte d'Ivoire), where hydrogeology has not yet been fully understood. The objective was to statistically determine the hydrogeological parameters responsible for optimizing the productivity of a borehole in order to guarantee a sustainable water supply for the populations of the Bounkani region. To achieve this objective, statistical analyses of the hydrogeological parameters, derived from existing drilling technical data sheets, were performed using Benford's law, the chi-square test, and focused principal component analysis (FPC) to obtain significant correlations between the hydrogeological parameters with a p-value < 0.05. Benford's law combined with the chi-square goodness-of-fit test showed that flow rate and specific flow rate obey Benford's law. However, the static level, alteration thickness, water arrival depth, and total drilling depth contradict this law. In addition, flow rate, specific flow rate, and water inflows are predominant in the first 60 meters of total drilling depth. Water inflows are mainly observed when alteration thicknesses are located within the first 41 meters, which also shows low fluctuation in static levels in boreholes in the Bounkani region. In summary, this study made it possible to determine the threshold values for hydrogeological parameters that must not be exceeded in order to optimize future boreholes in the study area.