Water resilience in arid landscapes: Unveiling the water potential in the Drâa River Basin (Central-East Morocco)

During the last decades, most Southern Atlasic Mountains basins have experienced a decline in precipitation and increased evapotranspiration rates, leading to a notable impact on water availability. The Drâa River Basin (DRB) is a large Moroccan arid area where water security is vulnerable to climate change. The limitation and the absence of perennial water resources exerted a high pressure on groundwater (GW) as the primary alternative for drinking and ecological development. Consequently, exhaustive groundwater abstraction has resulted in aquifer overexploitation, leading to an alarming decline in the water level. In such a situation, water availability has become a major concern. The current water resources must be managed based on the already water stress situation to ensure sustainable preservation for the future. This study aims to explore the potential of water resources in DRB by assessing the different components and interactions of the hydrological cycle (e.g., meteorology, hydrology, hydrogeology, and agriculture activity). The obtained results suggest that water demand is expected to significantly exceed the capacity of existing hydraulic infrastructure under global changes. The High Atlas Mountains, giving rise to the most perennial rivers and contributing to the recharge process for many aquifers, have shown decreasing in the precipitation received. Unbalanced discharges between saline contributions (from the El Maleh and Onila rivers) and fresh contributions (from the M’Goun and Dades rivers) are expected to raise water salinity in the Mansour Eddahbi reservoir in the coming decades. The combined effects of high evaporation and overexploitation cause saline water flowing into the Middle DRB to reach alarming levels. The land use scenarios established in the region suggest a complete depletion in groundwater storage for many aquifers within the next two decades, proclaiming more precautions to ensure and answer the high water demand. Our results can support decision-makers in managing the water and land use of the area more effectively.