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

Abstract

In Burkina Faso, the basement aquifers represent a major asset in terms of quantity and quality, for both drinking and irrigation purposes for rural populations. They provide water resources that can guarantee the long-term needs of the populations, provided that a sustainable management policy for these resources is adopted. Yet, any groundwater resource management policy is necessarily linked to a better knowledge of aquifer recharge mechanisms, which is yet to be fully assessed in the Sahelian basement area. The objective of this study was to characterize the recharge mechanism within the experimental site of Sanon, located in the basement zone in Burkina Faso, using a coupling of hydrodynamic and chemical approaches. The hydrodynamic approach consisted of monitoring the spatial and temporal distribution of the piezometric levels of the aquifers along a north–south and east–west transect and determining soil infiltration capacity. The hydrochemical characterization of the aquifers was carried out through an analysis of groundwater samples from the concerned aquifers and daily tracing of the electrical conductivity of the aquifer water. The cross-analysis from the results of the implemented approaches shows a direct recharge mechanism through rainwater infiltration in the central valley, an indirect recharge mechanism in the lowlands, and a recharge mechanism by lateral transfers in the peripheral aquifers of the Sanon experimental catchment. The existence of a piezometric dome reveals in the central valley a zone of preferential recharge and water movement. The water of the central valley is the least mineralized with electrical conductivities below 100 µS/cm. This mineralization follows the direction of the water flow.

Daily Simulation of the Rainfall–Runoff Relationship in the Sirba River Basin in West Africa: Insights from the HEC-HMS Model

“…This could further be explained by the fact that most hydrological models are rarely sensitive to potential evapotranspiration [4,76,77], which typically affects antecedent soil moisture levels between rainfall events, especially in the case of continuous-based simulations of the water cycle. Also, while intricate relationships in neighboring contexts between surface runoff and groundwater have been reported, such as preferential recharge pathways or groundwater feedback through rising tables [78,79], no such significant control from groundwater to surface runoff was observed in this study. In fact, previous studies highlighted that in the SRB, flood magnitude is largely influenced by surface processes rather than groundwater flow, as the river basin hydrology remains closely dependent on rainfall variability [33].…”

Future climate or land use? Attribution of changes in surface runoff in a typical Sahelian landscape

“…Besides, the capacity of populations living in these regions to adapt to climate change and variability impacts remains low [Serdeczny et al, 2017]. In such droughtprone contexts, improving local resilience through integrated water management should both consider land use decisions, water use and allocation [Belemtougri et al, 2021, Fovet et al, 2021, Kafando et al, 2021, Zipper et al, 2018. This, in turn, requires, at the core, a deeper understanding of the individual and combined contributions of climate and land use changes on the hydrological cycle, which is generally not well assessed, especially for such West African watersheds [Aich et al, 2015, Yira et al, 2017, Yonaba, 2020, Gbohoui et al, 2021.…”

Why Do Small Earth Dams Deteriorate: Insights from Physical Investigations in the West African Sahel

“…In sub-Saharan Africa, particularly in the West African Sahel, dams play a pivotal role in the mobilization of surface water, which is the most accessible and readily exploitable resource [6][7][8][9]. According to [10], despite inventory difficulties, the number of small dams is estimated at 1700 in Burkina Faso, 800 in Mali, 600 in Ivory Coast, and 500 in Ghana.…”