Addressing Climate Change in Pacific Northwest Water Resources

1. Pacific Northwest Water Resources Planning Case Studies Addressing Climate Change • Alan F. Hamlet, • Philip W. Mote, • Richard Palmer • Dennis P. Lettenmaier • JISAO/CSES Climate Impacts Group • Dept. of Civil and Environmental Engineering • University of Washington

2. Recession of the Muir Glacier Aug, 13, 1941 Aug, 31, 2004 Image Credit: National Snow and Ice Data Center, W. O. Field, B. F. Molnia http://nsidc.org/data/glacier_photo/special_high_res.html

3. Simulated Changes in Natural Runoff Timing in the Naches River Basin Associated with 2 C Warming • Increased winter flow • Earlier and reduced peak flows • Reduced summer flow volume • Reduced late summer low flow

4. Water Supply and Demand • Changes in the seasonality water supply (e.g. reductions in summer) • Changes in water demand (e.g. increasing evaporation) • Changes in drought stress • Increasing conflicts between water supply and other uses and users of water • Energy Supply and Demand • Changes in the seasonality and quantity of hydropower resources • Changes in energy demand • Increasing conflicts between hydro and other uses and users of water • Instream Flow Augmentation • Changes in low flow risks • Changes in the need for releases from storage to reproduce existing streamflow regime. • Changes in water resources management related to water quality (e.g. to provide dilution flow or to control temperature)

5. Flood Control and Land Use Planning • Changes in flood risks • Changes in flood control evacuation and timing • Dam safety • Impacts in Estuaries • Impacts of sea level rise and changing flood risk on low lying areas (dikes and levies) • Impacts to ecosystem function • Changes in land use policy (coastal armoring, land ownership, FEMA maps) • Long-Term Planning, Water Resources Agreements, Water Law and Policy • Water allocation agreements in a non-stationary climate (e.g. water permitting) • Appropriateness of the historic streamflow record as a legal definition of climate variability • Need for new planning frameworks in a non-stationary climate • Transboundary implications for the Columbia Basin

6. Water Supply Case Study for Seattle Public Utilities Wiley, M. W. 2004. Analysis techniques to incorporate climate change information into Seattle's long range water supply planning. M.S.C.E. thesis, Dept. of Civil and Environmental Engineering, College of Engineering, University of Washington, Seattle.

7. Effects to the Cedar River (Seattle Water Supply) for “Middle-of-the-Road” Scenarios +1.7 C +2.5 C

8. Transient SWE simulation from HadCM3 (A2) GCM run (with running 10 year average smoothing) • Simulated from observed climate shows a declining trend of ~3KAF per decade (1935-2000) • HadCM3 simulated declines ~4KAF per decade Figure courtesy of Matt Wiley and Richard Palmer at CEE, UW

9. In sensitive areas, systematic reductions in summer water availability will decrease the yield of water supply systems. Master's Thesis: Wiley, M.W. (2004). "Analysis Techniques to Incorporate Climate Change Information into Seattle’s Long Range Water Supply Planning," University of Washington

10. Salmon Restoration in the Snohomish River Basin Battin J., Wiley, M.W., Ruckelshaus, M.H., Palmer, R.N., Korb, E., Bartz, K.K., Imaki, H., 2007. Projected impacts of climate change on salmon habitat restoration, Proceedings of the National Academy of Sciences of the United States of America, 104 (16): 6720-6725

11. DHSVM → SHIRAZ linkage • Incubation peak flow • the maximum instantaneous flow recorded between 15 September and 15 February • maximum mean daily flow recorded between 15 September and 15 February • Incubation temperature • mean water temperature for the period 15 September to 15 February • mean water temperature for two subperiods: • 15 September-30 November • 1 December-15 February • Pre-spawning temperature • mean of daily maximum temperatures for the period 15 July – 15 October. • mean of daily maximum temperatures for 3 subperiods: • 15 July-14 August • 15 August-14 September • 15 September-15 October • mean temperature for the 3 subperiods: • 15 July-14 August • 15 August-14 September • 15 September-15 October • Smolt migration temperature • Mean of daily maximum temperatures for the period 15 March – 15 June. • Mean temperature for the period 15 March – 15 June. • Mean temperature for the following subperiods: • 15 March-15 April • 15 April-15 May • 15 May-15 June • Minimum spawning flow • Lowest instantaneous flow between 15 September and 15 November.

12. Climate Impacts – on high stream flow Sept –Feb.

13. Chinook Population Impacts-GFDL Mean population of wild spawners and percent falling below the threshold in GFDL Model

14. Impacts to the Columbia River Hydro System

15. Impacts on Columbia Basin hydropower supplies • Winter and Spring: increased generation • Summer: decreased generation • Annual: total production will depend primarily on annual precipitation (+2C, +6%) (+2.3C, +5%) (+2.9C, -4%) NWPCC (2005)

16. Warming climate impacts on electricity demand • Reductions in winter heating demand • Small increases in summer air conditioning demand in the warmest parts of the region NWPCC 2005

17. Climate change adaptation may involve complex tradeoffs between competing system objectives Source: Payne, J.T., A.W. Wood, A.F. Hamlet, R.N. Palmer and D.P. Lettenmaier, 2004, Mitigating the effects of climate change on the water resources of the Columbia River basin, Climatic Change Vol. 62, Issue 1-3, 233-256

18. Flood Control vs. Refill : Current Climate Full

19. Flood Control vs. Refill : Current Climate : + 2.25 oC No adaption Streamflow timing shifts can reduce the reliability of reservoir refill + 2.25 oC Full

20. Flood Control vs. Refill : Current Climate : + 2.25 oC No adaption : + 2.25 oC plus adaption Streamflow timing shifts can reduce the reliability of reservoir refill + 2.25 oC Full Optimization Workshop: http://www.ce.washington.edu/pub/leesy/ “Workshop”

21. Transboundary Implications for the Columbia River Hydrosystem

22. Changes in Simulated April 1 Snowpack for the Canadian and U.S. portions of the Columbia River basin (% change relative to current climate) 20th Century Climate “2040s” (+1.7 C) “2060s” (+ 2.25 C) -3.6% -11.5% -21.4% -34.8% April 1 SWE (mm)

23. Effects of Basin Winter Temperatures Northern Location in BC (colder winter temperatures) Southern Location in WA (warmer winter temperatures)

24. Implications for Transboundary Water Management in the Columbia Basin • Climate change will result in significant hydrologic changes in the Columbia River and its tributaries. • Snowpack in the BC portion of the Columbia basin is much less sensitive to warming in comparison with portions of the basin in the U.S. and streamflow timing shifts will also be smaller in Canada. • As warming progresses, Canada will have an increasing fraction of the snowpack contributing to summer streamflow volumes in the Columbia basin. • These differing impacts in the two countries have the potential to “unbalance” the current coordination agreements, and will present serious challenges to meeting instream flows on the U.S. side. • Changes in flood control, hydropower production, and instream flow augmentation will all be needed as the flow regime changes.

25. References for Some Existing Climate Change Water Planning Studies in the PNW • Seattle Water Supply (Wiley 2004) • White River Basin (Ball 2004) • Snohomish Basin (Battin et al. 2007) • Columbia Hydro System (Hamlet et al. 1999; Payne et al. 2004, NWPCC 2005) • Columbia Basin Flood Control (Lee et al. 2007) Ball, J. A. 2004. Impacts of climate change on the proposed Lake Tapps-White River water supply, M.S.C.E. thesis, Dept. of Civil and Environmental Engineering, College of Engineering, University of Washington, Seattle. Battin J., Wiley, M.W., Ruckelshaus, M.H., Palmer, R.N., Korb, E., Bartz, K.K., Imaki, H., 2007. Projected impacts of climate change on salmon habitat restoration, Proceedings of the National Academy of Sciences of the United States of America, 104 (16): 6720-6725 Hamlet, A. F. and D. P. Lettenmaier. 1999b. Effects of climate change on hydrology and water resources in the Columbia River Basin. Journal of the American Water Resources Association 35(6):1597-1623. Lee, S.Y., A.F. Hamlet, C.J. Fitzgerald, S.J. Burges, D.P. Lettenmaier, 2007: Optimized Flood Control in the Columbia River Basin for a Global Warming Scenario, ASCE J. Water Resources Planning and Management (in review) Payne, J. T., A. W. Wood, A. F. Hamlet, R. N. Palmer, and D. P. Lettenmaier. 2004. Mitigating the effects of climate change on the water resources of the Columbia River basin. Climatic Change 62:233-256. NW Power and Conservation Council, 2007, Effects of Climate Change on the Hydroelectric System, Appendix N to the NWPCC Fifth Power Plan, http://www.nwcouncil.org/energy/powerplan/plan/Default.htm Wiley, M. W. 2004. Analysis techniques to incorporate climate change information into Seattle's long range water supply planning. M.S.C.E. thesis, Dept. of Civil and Environmental Engineering, College of Engineering, University of Washington, Seattle.