Assessing the Future Climate Change Impacts on the Foum El Oued Groundwater Aquifer in Laâyoune, Morocco: A Numerical Modeling Approach

Water resource management in arid regions requires the provision of decision support tools that consider the impact of climate change as a structural reality. In the Laâyoune region, located in the south of Morocco, the Foum El Oued aquifer serves as a significant fresh water reservoir in a coastal area and plays a vital role in supplying water to the city of Laâyoune and neighboring municipalities. This study focuses on understanding and preserving this essential water resource, which is extensively utilized for drinking water supply, agriculture, and industrial purposes. However, due to the combination of reduced natural replenishment from the infiltration of Oued floods and increased pumping activities, groundwater has been overexploited, leading to the degradation of water quality and a considerable decline in the piezometric level. Consequently, an imbalance has emerged at the natural saltwater interface, resulting in seawater intrusion into the freshwater to compensate for the created depression. To address this issue, the objective of this work is to develop a finite difference hydrodynamic and seawater model that considers the effects of future climate change on the Foum El Oued aquifer, based on available hydrogeological data. The simulation results reveal that by 2050, under the projected conditions, the interface toe would have advanced by a distance of 6.5 km. At this time, the concentration of 10 g/l will reach a distance of 6.2 km, and the highest concentration (35 g/l) will extend to 5.8 km. This GW model serves as a crucial decision support system for water resource management, particularly for the population of Laâyoune and the irrigation of the Foum El Oued agriculture area. By implementing effective management strategies, the coastal area can be protected from contamination, ensuring its sustainable use and preventing abandonment due to increasing salinity levels in irrigation and pumping wells.