Type of Presentation

Poster

Session Title

Linking Metrics to Climate Impact Pathways and Restoration Performance Monitoring across Puget Sound Floodplains and Estuaries

Description

The Nooksack River drains an approximately 2000 km2 watershed in the North Cascades in Whatcom County, Washington and is a valuable freshwater resource for regional municipalities, industry, and agriculture, and provides critical habitat for endangered salmon species. With a maritime climate and a high relief basin with glacial ice (3400 hectares), the streamflow response in the Nooksack River is sensitive to increases in temperature, thus forecasting the basins response to future climate is of vital importance for water resources planning purposes, especially during low-flow months in the summer when precipitation is minimal. We apply the Distributed Hydrology Soil Vegetation Model (DHSVM; Wigmosta et al., 1992) with newly developed coupled dynamic glacier model (Clarke et al., 2015) to simulate hydrologic processes in the Nooksack River basin.

We calibrate and validate the DHSVM to observed glacial mass balance and glacial ice extent as well as to observed daily streamflow and SNOTEL data in the Nooksack basin using a gridded meteorological forcing data set (1950-2010; Livneh et al., 2013). We simulate forecasted climate change impacts, including glacial recession on streamflow, using gridded daily statically downscaled data from global climate models of the CMIP5 with RCP4.5 and RCP8.5 forcing scenarios developed using the multivariate adaptive constructed analogs method (Abatzoglou and Brown, 2011). Simulation results project an increase in winter streamflows due to more rainfall rather than snow, a decrease in spring snow-melt runoff with peaks that occurring earlier in the year, and lower summer flows. Glacier melt contribution to streamflow initially increases throughout the first half of the 21st century and decreases in the latter half after glacier ice volume decreases substantially.

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Modeling the Effects of Forecasted Climate Change on Streamflow in the Nooksack River Basin

2016SSEC

The Nooksack River drains an approximately 2000 km2 watershed in the North Cascades in Whatcom County, Washington and is a valuable freshwater resource for regional municipalities, industry, and agriculture, and provides critical habitat for endangered salmon species. With a maritime climate and a high relief basin with glacial ice (3400 hectares), the streamflow response in the Nooksack River is sensitive to increases in temperature, thus forecasting the basins response to future climate is of vital importance for water resources planning purposes, especially during low-flow months in the summer when precipitation is minimal. We apply the Distributed Hydrology Soil Vegetation Model (DHSVM; Wigmosta et al., 1992) with newly developed coupled dynamic glacier model (Clarke et al., 2015) to simulate hydrologic processes in the Nooksack River basin.

We calibrate and validate the DHSVM to observed glacial mass balance and glacial ice extent as well as to observed daily streamflow and SNOTEL data in the Nooksack basin using a gridded meteorological forcing data set (1950-2010; Livneh et al., 2013). We simulate forecasted climate change impacts, including glacial recession on streamflow, using gridded daily statically downscaled data from global climate models of the CMIP5 with RCP4.5 and RCP8.5 forcing scenarios developed using the multivariate adaptive constructed analogs method (Abatzoglou and Brown, 2011). Simulation results project an increase in winter streamflows due to more rainfall rather than snow, a decrease in spring snow-melt runoff with peaks that occurring earlier in the year, and lower summer flows. Glacier melt contribution to streamflow initially increases throughout the first half of the 21st century and decreases in the latter half after glacier ice volume decreases substantially.