Mountains act as global ‘water towers’ storing and releasing water to downstream areas to sustain environmental and human water demands. Compared to downstream, mountains generate much higher runoff from rain as a result of orographic precipitation and delay the release of water by storing it in snow and glaciers. Because of their buffering capacity, for instance by supplying glacier melt water during the hot and dry season, mountains provide a relatively constant water supply to downstream areas (Immerzeel et al., 2019; Viviroli et al., 2003). This water is used to sustain ecosystems, irrigate crops and produce food (Biemans et al., 2019) for domestic and industrial purposes, and to generate the bulk of the available hydropower (Gernaat et al., 2017; Hoes et al., 2017).

Mountain ranges are vulnerable systems: climate change hits harder at high altitudes, where temperature increases more rapidly than in the surrounding lowlands (Pepin et al., 2015), and affects the storage of water as glacier ice and snow (Kraaijenbrink et al., 2017). This leads to changes in hydrological regimes with seasonal shifts and faster hydrological response (Huss and Hock, 2018; Lutz et al., 2014). On the other hand, pressure on high mountain water resources will increase with growing downstream water demand under socioeconomic development. Climate change also leads to an increase in extreme weather in mountains, which already experience frequent extreme weather. This strongly increases the risk of floods and landslides.

In summary, mountain regions and their downstream areas are subject to a variety of potential adverse future changes, which need to be taken into account in climate change adaptation and investment decisions.

FutureWater approach

FutureWater has unique in-house, world leading mountain hydrology expertise. This expertise is used in research and consultancy, where we frequently deploy our Spatial Processes in Hydrology (SPHY) model, which has specific strengths in simulating high mountain hydrology under data scarce conditions. We develop projections of future water availability, provide detailed insight in expected shifts in seasonality of water supply and can assess how these correspond to future changes in water demand. For the hydropower sector we provide detailed future flow and power generation projections to aid investment decisions, and we provide climate risk assessments in mountainous regions for a range of sectors. We provide research and advice at scales ranging from single catchments to large river basins. Our assessments do not stop at the transition from highland to lowland, but we make the link between upstream and downstream to provide advice on integrated water resource management and consideration of the full water-food-energy nexus.

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