1. Improving Estimates of Hydrologic Extremes: Applications to the Olympic National Forest Ingrid Tohver PNW Climate Science Conference September 14, 2011 Seattle, WA

2. Partnerships with Stakeholders Olympic National Forest and Park: Kathleen O’Halloran Luis Santoyo Bill Shelmerdine Robert Metzger Robin Stoddard Climate Impacts Group & Civil and Environmental Engineering, University of Washington: Alan Hamlet Se-Yeun Lee Ingrid Tohver Robert Norheim

3. Project Premise Assess potential impacts of climate change on federal lands and incorporate projections into management practices Update estimates of extreme streamflows Support protection of fish and wildlife habitat Support road maintenance and flood control infrastructure Photos courtesy of Olympic National Park

4. USGS Streamstats Tool Web-based GIS tool used to estimate streamflow statistics: Inputs = basin size, annual precipitation and elevation DEM & PRISM datasets Regression equation developed by USGS calculates statistics http://water.usgs.gov/osw/streamstats/ Climatic caveats: Unchanging mean annual precipitation Seasonality is lost in calculation

5. Climate Change Scenarios for the PNW Figures’ source: Mote and Salathé 2010 Temperatures warm across all projections Mean annual precipitation projections do not show a clear trend Seasonal signal of precipitation shifts is lost in the annual projections

6. Contrasting Hydrologic Models Physically-based VIC Model Explicitly integrates climate conditions Applies future T & P projections to estimate daily runoff at each grid cell Daily runoff used to estimate shifts in extreme streamflow frequency Spatial resolution: Fine - 1/16 th ° Aggregate - 12 digit HUCs USGS Regression-based model Regressions applied based on region Historical and future P from climate models

7. USGS VIC Comparing Results Shows increases in annual precipitation only No response to warmer temperatures or the changing seasonality of precipitation Captures the temporal and spatial variability in the climate models Responds to future warming and increases in winter precipitation with a rise in flood severity

8. Difference of Sensitivity

9. Shift in Flood Severity 1/16 th degree 12-digit HUCs Comparing the Future to Historical 100-Year Flood – 2040s Map: Rob Norheim

10. Shift in Low Flow Severity Comparing the Future to Historical 7Q10 – 2040s 1/16 th degree12-digit HUCs Map: Rob Norheim

11. Summary Statistics: Low Flow

12. Summary Statistics: Flood

13. Future Applications Implement extreme streamflow analysis over PNW domain Assess changes in risk to fish habitat and infrastructure in other National Forests/Parks: North Cascades Mt Baker/Snoqualmie Mt Rainier