Hydrology and Water Resources: Current Research

Incorporating Climate Change Information into Seattle's Long Range Water Supply Planning

Hydrology and Water Resources

In This Section . . .

Personnel

Richard Palmer, CIG and UW Civil Engineering (contact person)
Matthew Wiley, UW Civil Engineering
Kasey Kudamik, UW Civil Engineering

Background

Seattle Public Utilities (SPU) serves approximately 1.3 million customers in the King County metropolitan area (SPU 2004). Seventy percent of the water SPU serves originates in the Cedar River watershed; the remaining 30% is drawn mostly from the South Fork Tolt River watershed and the Highline wellfield (ibid). Both the Cedar and the Tolt are located on the western slope of the Cascade Mountains near the current mid-winter snowline. Projected decreases in winter snowpack as a result of climate change could have a significant impact on water supply reliability and management in the Cedar and Tolt systems.

Research Questions

SPU is sponsoring research in the University of Washington's Department of Civil Engineering to assess the potential impacts of climate change on SPU's water supply. A technical focus of this research is developing techniques for downscaling global climate change scenarios to localized river basins. Another major theme of this research is exploring and quantifying the level of uncertainty associated with each step of the climate impacts assessment process.

Evaluation metrics for assessing the impact of climate change on SPU's water supply include changes in:

April 1 snowpack,
Summer reservoir inflows and fall reservoir storage levels,
The ability to meet instream flow requirements, and
general system yield

Climate change impacts on residential water demand is also explored. A final report is expected by summer 2004.

Research

Climate Impacts Group