Research

Hydrology and Water Resources

Current Research

Current research at the Climate Impacts Group (CIG) on Pacific Northwest (PNW) climate and hydrology/water resources includes:

Characterizing 20th Century Hydrologic Conditions

• Constructing high quality long-term precipitation and temperature data sets for the PNW. The statistical methods developed in this project will be used to remove temporal inhomogeneities in historic co-operative weather station records. The corrected datasets will then be used to extend retrospective Columbia River basin hydrologic simulations back to 1916.
• Detecting and attributing 20th century trends in PNW snowpack. This research will provide resource managers a clearer picture of trends in PNW snowpack and the principal causes for the decline.
• Characterizing 20th century variability and trends in streamflow, especially spring and summer flow, in unregulated rivers in the Northwest

Improving Seasonal to Interannual Streamflow Forecasting

• Developing extended mid-range streamflow forecasts for Puget Sound municipal water supplies using NCEP climate forecasts. These will provide operators longer lead times for developing responses for instream flow releases, flood management, and supply management.
• Developing new medium to long-range streamflow forecasting methods for the Columbia basin. The methods developed will allow for forecasting of changes in the probability distributions of ensemble streamflow forecasts for the Columbia River at lead times of about two weeks to one month.

Determining the Impacts and Implications of Anthropogenic Climate Change

• An integrated evaluation of the impacts of climate change on the major water providers in the Puget Sound Metropolitan area, including Seattle, Everett, and Tacoma. We are evaluating:
1. climate change impacts on water supply reliability, the ability to meet instream flow requirements, hydropower production in the Sultan River, and on water demand, and
2. current infrastructure development plans, in terms of their ability to cope with these projected changes
• Examination of the impacts of climate variability and change on water use in the Snake River basin. Using a water resources simulation model integrating surface and groundwater effects and streamflow simulations from the VIC hydrologic model, we are examining the impacts of climate variability and change on:
1. current and proposed future operating plans, and
2. tradeoffs between irrigated agriculture, instream flow requirements, and energy production.
• Developing climate change streamflow scenarios for water planning studies
• Modeling climate change and land use impacts on salmon recovery in the Snohomish River basin. This study, conducted in partnership with NOAA and the Department of Civil and Environmental Engineering at the University of Washington, evaluates the effects of future climate change and changes in large-scale land use on Chinook salmon in the Snohomish River basin.

Related Work

Hydrology and water resources research at the CIG benefits from externally funded, climate-related research projects and programs that key CIG research personnel conduct or are otherwise affiliated with, including the following:

• As part of the Accelerated Climate Prediction Initiative (ACPI) funded water management investigations for the western US, CIG-affiliated researchers and graduate students have been involved with:
  • A study of adaptive management strategies for the Columbia River basin in response to climate change using the ColSim reservoir operation model (Payne et al. in press). These investigations were some of the first attempts to look explicitly at the transient variability of the climate model simulations for the PNW, and to attempt to mitigate the impacts of these changes in streamflow variability using conventional water resources engineering techniques. Contact: Alan Hamlet.
  • A study on the implications of climate change on California’s Sacramento-San Joaquin River basin hydrology and water resources (Van Rheenen et al. 2002). The impacts of climate variability and change on water resources in California’s Central Valley were studied using a suite of models that predict future precipitation and temperature, watershed hydrology, and reservoir system performance. Results from the water resources system model indicate that achieving and maintaining status quo system performance in the future would be nearly impossible under projected climate change. Demand modification and system infrastructure improvements will be required to account for the volumetric and temporal shifts in flows predicted to occur in the Sacramento-San Joaquin River basins. Contact: Dennis Lettenmaier.
• Nick Bond (UW/JISAO) and Gabe Vecchi (NOAA/PMEL) are examining the relationships between the tropical Madden-Julian Oscillation and precipitation and flooding in the PNW.