An overview of groundwater resources evolution in North Africa: sustainability assessment of the CI aquifer under natural and anthropogenic constraints

Given the complex links to the major economic activities and climate variability, water is becoming the most fiercely contested resource, challenging human survival and food security especially in arid hot dry regions, such as in the Middle East and North Africa areas (MENA). In the Kebili and Tozeur regions in southern Tunisia, groundwater resources undergo abusive exploitation mostly for agricultural activities. The lack of efficient management and adequate conservation strategies to ensure sustainable exploitation has resulted in gradual irreversible ecological and geological effects. Thus, this review paper provides a useful background synthesis for the critical assessment of the recursive dynamic substantial increase in freshwater in these regions, using a general equilibrium model of hydrodynamic and chemical changes of aquifers based on several water scarcity indices and economic-ecological factors. The collected data highlight the good correlation between the reviewed studies and the observed and (or) measured disturbance of the natural functioning of the deep confined aquifers, manifested by the gradual severity of the resulted environmental issues, the permanent irreversible depression of the water table, aquifer decompression, land subsidence in the Douz area, and contamination by petroleum flows, with 4 g/L of asphalt and 12 to 90 µg/L of cadmium in northern Kebili. Based on the assembled evidence, water scarcity has heavily influenced the equilibrium of these resources, and the adopted conservation plans have been insufficient to ensure economic incentives for environmental natural resources conservation (the annual average loss of fertile land is 1.25 ha). A detailed equilibrium analysis, relying on evaluating the water productivity-water exploitation ratio, is undoubtedly necessary for improving the integration among different decision makers. Moreover, a re-examination of the resulting impacts of the previously implemented strategies for reliable database development is the key to the successful handling of this transitory fragile situation.