Recharge Estimation of Hard Rock Aquifers under Sahelian Climate Conditions Using Water Table Fluctuation: Case Study of Tougou Catchment, Burkina Faso

Abstract

This study aims to characterize water table fluctuations and estimate groundwater recharge in the Tougou catchment located in the Sahel zone of Burkina Faso. Water table fluctuation and groundwater budget approaches are developed on an experimental site equipped with observation wells. The trends of water fluctuations in the different layers of the weathering profile are similar. There is a time-lag response of groundwater recharge to the daily precipitation occurrences. The interaction between the upper (clayey alteration) and lower (transition zone-fractured schist complex) parts of the weathering profile shows that generally the hydraulic head in the upper part is higher than that of the lower part due to difference in drainage porosity. The latter varies at the catchment scale between 0.006 and 0.009 and is inversely proportional to the saturated thickness of the clayey alteration layer. The groundwater recharge is annually estimated between 36 and 49 mm, which correspond to 6% and 9% of mean annual rainfall in the catchment. Annual evapotranspiration was estimated to be about 223 to 443 mm.

Use of Multidisciplinary Approaches for Groundwater Recharge Mechanism Characterization in Basement Aquifers: Case of Sanon Experimental Catchment in Burkina Faso

“…Although the volume of water stored in these aquifers is not as substantial, they contribute to the socioeconomic wellbeing of both rural and urban populations [5,6]. However, the rapid population growth, the improvement of living conditions, and the increase in water use due to economic activities contribute to increasing pressure on groundwater resources [7]. In addition, the development of sectors of activity with higher pollution potential (mining industries, agriculture) constitutes threats to the quality of groundwater resources [8][9][10].…”

“…Regarding the Burkina Faso basement complex, studies related to the characterization of groundwater recharge mechanism are almost nonexistent. A handful of previous attempts have mainly focused on quantifying groundwater recharge [7,[35][36][37]. However, most of these studies did not consider the pathways followed by the water throughout the soil layers to the aquifer, which might lead to uncertainties in the amount of recharge estimates [17,31,32].…”