Global and regional surface water quality impacts on sectoral water scarcity under climate variability

Abstract:

Water scarcity threatens people in various regions, and has predominantly been studied from a water quantity perspective. However, the provision of water for human uses and environmental health is dependent on both sufficient water availability, but also appropriate water quality for the intended use. We present global and regional surface water quality hotspots and discuss the impacts on sectoral water scarcity for different water use sectors (agriculture, domestic, manufacturing, energy) and ecosystems under climate variability.

We have developed a water scarcity framework coupling global surface water quality models (water temperature, salinity, organic pollution, nutrients) and global hydrological models with spatially-explicit global datasets of desalination and treated wastewater reuse capacities. In addition, the surface water quality responses and associated impacts on water scarcity during recent droughts have been studied for several river basins in Europe and the US based on analyses of both monitoring and simulated surface water quality data. Our water scarcity quantifications show that a combination of drought-induced changes in both water availability and quality (e.g. salinity) can exacerbate water scarcity, and that both water quantity and quality aspects should be considered when quantifying water scarcity for different sectoral uses. We conclude that alleviating water scarcity should therefore not only focus on increasing water availability and reducing water demands, but also on improving water quality.