1. Designing Hydrologic Modeling Studies to Support Diverse Climate Change Planning Needs in the Columbia River Basin
Alan F. Hamlet
Amy K. Snover
Kurt Unger
Philip W. Mote
Dennis P. Lettenmaier
JISAO/CSES Climate Impacts Group
Dept. of Civil and Environmental Engineering
University of Washington
WA State Department of Ecology

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

3. PNW Pilot Climate Change Planning Efforts:
West Side Cascades Partnerships:
Portland Water Bureau
Seattle Public Utilities
Tualitin Basin
White River-Lake Tapps
Snohomish River Basin
King Co.
Columbia Basin Partnerships:
Northwest Power and Conservation Council (BPA)
US Bureau of Reclamation (Boise)
Seattle District Corps of Engineers
Idaho Department of Water Resources

4. Recession of the Muir Glacier
On the left is a photograph of Muir Glacier taken on August 13, 1941, by glaciologist William O. Field; on the right, a photograph taken from the same vantage on August 31, 2004, by geologist Bruce F. Molnia of the United States Geological Survey (USGS).
According to Molnia, between 1941 and 2004 the glacier retreated more than twelve kilometers (seven miles) and thinned by more than 800 meters (875 yards).
Ocean water has filled the valley, replacing the ice of Muir Glacier; the end of the glacier has retreated out of the field of view. The glacier’s absence reveals scars where glacier ice once scraped high up against the hillside. In 2004, trees and shrubs grow thickly in the foreground, where in 1941 there was only bare rock.
Aug, 13, 1941
Aug, 31, 2004
Image Credit: National Snow and Ice Data Center, W. O. Field, B. F. Molnia

5. Collapse of the
Larsen B
Ice shelf,
Antarctica
March 5, 2002

6. Annual area (ha × 106) affected by MPB in BC
1910
1930
1950
1970
1990
2010
1.0
2.0
3.0
4.0
5.0
6.0
Year
8.0
7.0
1999
2001
2000
2003
2002
Annual area (ha × 106) affected by MPB in BC
2005
9.0
2004
Bark Beetle Outbreak in British Columbia
By last year, the total area of beetle-caused mortality spread over some 10 million hectares
(Figure courtesy Allen Carroll)

7. Trends in April 1 SWE
Mote P.W.,Hamlet A.F., Clark M.P., Lettenmaier D.P., 2005, Declining mountain snowpack in western North America, BAMS, 86 (1): 39-49

8. spring flows rise and summer flows drop
As the West warms,
spring flows rise and summer flows drop
Stewart IT, Cayan DR, Dettinger MD, 2005: Changes toward earlier streamflow timing across western North America, J. Climate, 18 (8):
Spring snowmelt timing has advanced by days in most of the West, leading to increasing flow in March (blue circles) and decreasing flow in June (red circles), especially in the Pacific Northwest.

9. An Opportunity to Provide Improved Access to Hydrologic Scenarios for Planning
As the public and professionals in the water management and policy arenas have become increasing concerned about the impacts of climate change on PNW water resources, demand for hydrologic scenarios suitable for planning purposes at a range of spatial scales has increased dramatically.
Currently there does not exist an up-to-date, comprehensive, and self-consistent data base of hydrologic scenarios for the Columbia River basin that is suitable for the range of planning activities the Climate Impacts Group is being asked to support.

10. WA House Bill 2860
$16 Million for studies related to enhancing water supplies in the Columbia River basin for irrigation and municipal water supply.
Up to $200 Million for implementing improvements identified by these studies.
Answers to FAQ regarding WA 2860 from the Department of Ecology website:

11. Water Planning Framework
Schematic of a Typical
Water Planning Framework
Observed Streamflows
Planning Models
System Drivers

12. Climate Change Scenarios
Schematic of Climate Change
Water Planning Framework
Observed Streamflows
Planning Models
Altered Streamflows
Climate Change Scenarios
System Drivers

13. The Need to Encompass Multiple Spatial Scales

14. Large Scale Planning Studies
Examples:
Hydro System Performance
Flood Control
Main Stem ESA
Transboundary Issues
Large-Scale Irrigation Impacts

15. Medium Scale Planning Studies
Examples:
Water Supply Planning
Yakima Basin
Okanogan Basin
Methow
Walla Walla Basin
WA State Water Resources Inventory Areas

16. Observed 20th century variability
Curves are fits to ln(CO2) for A2 (solid) and B1 (dashed)
Warming ranges are shown for 2020s, 2040s and 2090s relative to 1990s. Central estimates: 0.7C by 2020s, 1.7C by 2040s, 3.2C by 2090s. Pink box shows +/- 2 sigma for annual average temperature (sigma=0.6C). Red lines show previous generation of change scenarios. Until mid-century, emissions scenarios play a minor role in the temperature impacts. Towards the end of the century they play a big role. Conclusions: 1) Adaptation will be an essential component of the response to warming over the next 50 years. 2) Mitigation of greenhouse gas emissions will play an important role in determining the scope of late 21st century impacts. °C
Pacific Northwest

17. Observed 20th century variability%
-1 to +3%
+6%
+2%
+1%
Curves are fits to ln(CO2) for A2 (solid) and B1 (dashed)
Precip changes are shown for 2020s, 2040s and 2090s relative to 1990s. Central estimates: 1% by 2020s, 3% by 2040s, 6% by 2090s. Pink bar shows +/- 2 sigma for PNW annual precip.
Observed 20th century variability
-1 to +9%
-2 to +21%
Pacific Northwest

18. Daily Precipitation, Tmax, Tmin
Result:
Daily Precipitation, Tmax, Tmin

19. Schematic of VIC Hydrologic Model and Energy Balance Snow Model
6 km
1/16th
Deg.
6 km
PNW
Snow Model

20. Streamflow Locations Currently Under Consideration
Blue = Large Scale Planning Sites
Green = Snake River Sites
Red = Additional Sites in WA
Partnerships with OR, ID, and BC are being discussed with the intent to extend the number of sites in these areas.

21. Alternate Approach: DHSVM
Developed in the
UW Land Surface
Hydrology Research
Group at UW for over
a decade
a research tool, also
is used operationally
applied to small
catchments
DHSVM: Distributed Hydrology-Soil-Vegetation Model

22. Medium Scale Planning Studies
WA State Water Resources Inventory Areas

23. Some Potential Advantages of DHSVM Approach
Increased spatial resolution down to the watershed scale
Increased temporal resolution (high and low flow extremes)
Water temperature simulations
Simple ground water scheme improves base flow simulations
Future access to sediment transport capability (research)

24. Proposed Downscaling Approaches
Statistical Downscaling (GCM)
10 scenarios
Dynamic Downscaling (nested MM 5)
2 scenarios
Improvements in downscaling techniques will be implemented to allow evaluation of daily effects on flooding and low flow events.