Assessing past and future water demands under climate change and anthropogenic pressures on two Mediterranean basins

The Ebro (Spain) and the Hérault (France) are two contrasted catchments representative of the Mediterranean context. Simultaneous increases of population, irrigated areas, and industrial development observed in the recent pas associated with future climate change indicators point towards the necessity of considering the capacity of these catchments to satisfy water demand. This evaluation requires knowledge of the spatiotemporal dynamics of water demands and their main drivers. This paper thus presents a conceptual modelling framework to estimate water demand and its evolution. The Ebro basin is dominated by agricultural water demand, which has been highly increasing mostly due to the expansion of irrigated areas. In the Hérault basin, domestic demand has largely increased since the 1970s. Future water demand was assessed by the 2050 horizon under climatic and socio-economic scenarios. Results show that water demand should keep increasing notably irrigation requirements. This work is a first step in analyzing the capacity of each hydro-system to satisfy current and future water demands.