Modern and Past recharge of the Saharan Aquifer Systems by coupling geochemical tracers (14C, 36Cl,…) and hydrological modeling
Worldwide demographic pressure, urbanization, economic growth and development of irrigated agriculture all contribute to massive hikes in water demand levels that seriously jeopardize the availability, quantity and quality of the water resource. The Maghreb and the circum-Sahara area are particularly vulnerable to these threats because climate change amplifies this water stress by impacting the water balance as a whole, and groundwater recharge in particular. In these regions, groundwater is of strategic importance since surface water bodies are too rare.
But these massive deep groundwater reservoirs that were artesian in most of their surface are subject to intense mining since the 1950’s that has led to a substantial decline in the piezometric surface, as witnessed by the drying up of naturally flowing springs, drawdowns in pumped wells or loss of artesianism. This raises the question of the renewability and sustainability of this resource.
Face to this challenge, we will try to better constraint the modern and past recharge of two aquifer system : the North-Western Saharan Aquifer System (NWSAS) and the Nubian Sandstone Aquifer System (NSAS).