Flow characterization and modelling of a South Benin artesian aquifer system: Effects of hydraulic and storage properties and recharge on simulated heads across the artesian zone

Artesian outflows are important for local populations as pumping is not required for them to get access to such a groundwater resource. However, in many world’s artesian basins, free-flow cessations have occurred due to artesian head-drops. In this PhD thesis, a characterization and numerical modelling of head changes were performed for a south artesian basin of Benin so as to capture plausible artesian heads evolution under population growth and climate change. Sensitivity of the simulated heads to hydraulic and storage properties as well as recharge was analyzed so as to understand the properties that are most important in such modelling endeavors. We found that the artesian basin is structured into peripheral and central parts, which have different reactions to external stresses. The peripheral artesian zone was found adjacent to groundwater recharge areas and is more subjected to higher head-fluctuations and hence to temporal free-flow cessation compared to central artesian zones.