Hydrological Challenges and Competing Demands in the Mediterranean Region

Abstract The Mediterranean region is facing severe hydrological challenges. Rising temperatures, remarkable fluctuations in precipitation, more frequent and intense droughts, and widespread revegetation in the headwaters due to farmland abandonment explain the observed decreases in river discharge across the region. Particularly, farmland abandonment in mountain areas favors woody encroachment, increasing water consumption by vegetation and rainfall interception. In contrast to the reduction of surface water resources, lowland areas are experiencing a growing water demand, primarily driven by increasing consumption in irrigated agriculture (which accounts for over 80% of total water use), tourism resorts, and urban and industrial areas. This contradictory trend between water resources generation and water demand is responsible for increasingly marked tensions, driving many regions toward environmental and social collapse. This includes inland and coastal wetlands (such as deltas and marshes), which are now under threat of extinction or face severe conflicts between wildlife, vegetation, and agricultural demands. In this review, we examine the conflicts between runoff generation in the highlands and water consumption in the lowlands of the Mediterranean region in order to improve land and water management and to ensure the survival of key ecosystems. The development of socio-hydrological scenarios and adaptive governance strategies will be critical for anticipating future conflicts and designing sustainable pathways for the management of scarce water resources.