Projecting future local hydroclimatology: A framework for local water resource planners in the Animas River Basin at Durango, Colorado

Spring snowmelt provides up to 50--80% annual streamflow for much of the western US. However, increasing temperatures and decreasing precipitation have begun to affect the timing and magnitude of this process. This could begin to have serious implications for the region's water resources. Predicting future changes in hydroclimatology will provide a serious challenge for local water resource planners. The goal of this research was to project future changes in local winter and spring air temperature and precipitation along with impacts on stream flow for a typical small snowmelt fed river basin in the western US, the Animas River Basin in SW Colorado.;Following a historical analysis of basinwide hydroclimatology, statistical downscaling increased the resolution of, and built a linear relationship between, historical upper atmospheric reanalysis data to surface level mean air temperature and precipitation for several climate stations located across the basin. The same technique then increased the resolution of two GCMs from the Intergovernmental Panel on Climate Change (IPCC) over three scenarios using the same relationships between the historical upper atmospheric reanalysis data and the surface station climate data. Snowmelt streamflow magnitude and timing were then projected to 2099 based on their historical relationship to mean monthly winter and spring air temperature and precipitation while the snowmelt runoff model (SRM) projected losses/gains in basinwide snowmelt runoff relative to historical means. Results indicated a shift in both the timing and magnitude of peak spring streamflow resulting from increasing spring temperatures and decreasing winter precipitation across the basin. Despite these initial hydroclimatogical projections, a survey of water resource planners across the Animas River Basin revealed that little climate change research is currently included in basinwide plans. This study can provide local level water resource planners with a framework to incorporating climate change research into future water resource planning, something that is currently lacking in the relevant scientific literature.