Identifying At-Risk Snow Water Resources In The Great Basin

Harpold lab digging snow pits.

Snowmelt provides water for over a billion people globally and greater than 80% of the water resources for the State of Nevada.  These critical resources face an uncertain future as regional warming has the potential shift snow to rain, increase the energy available to melt snowpacks and intensify water demand from vegetation and the atmosphere.  The large hydro-climatic gradient across the Great Basin is likely to result in uneven snowpack response to warming temperatures with unknown consequences for ecosystem services and downstream water resources.

Determining future snow water availability requires quantifying the counteracting snowpack processes that promote greater water vapor loss (e.g. snowpack storage and release during high water demand) with those processes that promote greater water subsidy (e.g. more prolonged infiltration events and greater subsurface pressure heads). Predicting the effects of climate change on snowmelt-mediated hydrological processes is a critical scientific challenge for water security in the Western U.S. 

This project investigates how changing snowpacks are modulated by landscape hydrological processes through a multi-scale approach that integrates field observations, remote sensing of snow and vegetation, and physically-based modeling. 

Completion of the project offers numerous economic and social benefits for the residents of Nevada. For example, the development of a new drought index that includes snowpack storage could provide early warning of water shortages in areas with limited observations. Satellite estimates of vegetation health will be used to identify Great Basin ecosystems and vegetation types vulnerable to altered snow water availability.  The project will also link changing streamflow to downstream water rights and economic productivity to increase information available to policy makers.