In this project we will accomplish the following using the Saharan fossil aquifer systems in North Africa, Lake Chad Basin Aquifer and in the Arabian Peninsula as test sites: (1) investigate whether the rapid response observed over the Nubian Sandstone Aquifer System (NSAS: Abdelmohsen et al., 2019) could be common to many of the aquifers worldwide, (2) identify the conditions under which such rapid flow occurs, and (3) develop sustainable and/or optimum scenarios for groundwater management for aquifers showing evidence for rapid groundwater flow using historical climatic data.