1. The Columbia Basin Climate Change Scenarios Project:
Overview of Study Design, Downscaling Approaches, and Selected Products
Alan F. Hamlet
Marketa McGuire Elsner
JISAO/CSES Climate Impacts Group
Dept. of Civil and Environmental Engineering
University of Washington

2. Team Acknowledgements:
Marketa McGuire Elsner
Guillaume Mauger
Rob Norheim
Eric Salathé
Pablo Carrasco
Jeff Deems
Ingrid Tohver
Se-Yeun Lee

3. Study Partnerships Funding Partners:
WA Department of Ecology (via HB 2860)
Bonneville Power Administration
Northwest Power and Conservation Council
Oregon Water Resources Department
BC Ministry of the Environment
Collaborative Partners:
Montana Department of Natural Resources
Idaho Department of Water Resources
USBR, Boise Regional Office
USACE, Seattle and Portland Districts

4. Study Objectives:
Provide comprehensive hydrologic data bases to support water planning at a range of spatial and temporal scales in the Columbia River basin and PNW.
Increase spatial resolution of hydrologic models to capture smaller basins relevant to planning.
Conduct pilot studies using fine scale hydrologic simulation tools and compare to macro-scale tools that are currently being more widely implemented.
Improve range of products and services available, and construct tools and data processing methods to make future updates easier (and less expensive) to produce.

5. Overlap with the Washington State Climate Impacts Assessment (HB 1303)

6. A comprehensive climate change impacts assessment for Washington State
Human Health
Infrastructure
Agriculture/Economics
Water Resources
A comprehensive climate change impacts assessment for Washington State
Coasts
Energy
In this impacts assessment, we are evaluating the impacts of climate change on essentially eight sectors, including hydrology and water resources, energy, salmon, forest resources, coasts, agriculture, and human health. The Climate Impacts Group has performed similar assessments in the past; however, this work includes new sectors in which there is little past research. These include coasts, agriculture, health, and infrastructure.
We will also be assessing barriers, both legal and institutional, to climate change adaptation.
Forest Resources
Salmon
Adaptation 6

7. Downscaling Global Climate Change Scenarios for the PNW

8. 21st Century Climate Impacts for the Pacific Northwest Region
Mote, P.W. and E. P. Salathe Jr., 2009: Future climate in the Pacific Northwest (in review)

9. Overview of Downscaling Approaches:
Delta Method
Realistic daily time series and spatial variability.
91 years of variability associated with each time frame and emissions scenario.
Only incorporates changes in mean T and P.
Bias Corrected and Statistically Downscaled GCM Data (BCSD)
Incorporates more information from the GCMs, but as a result may also inherit undesirable aspects of GCMs as well.
Facilitates trend analysis, examination of potentially altered variability.
Hybrid Methods
Takes time series and spatial behavior from the observed record, but incorporates more detailed statistical changes from the GCMs.

10. Typical Applications of Each Downscaling Approach:
Delta Method
Sensitivity studies
Summary of all GCM projections in one run (limited runs to identify the central tendency
Bias Corrected and Statistically Downscaled GCM Data (BCSD)
Trend Analysis of Hydrologic Variables
Ensemble uncertainty analysis for 30-year windows at any time in the 21st century (flexible time period of analysis)
Hybrid Methods
Ensemble analysis of water systems over 90 years of variability.
Flood and low flow analysis
Any application that needs very realistic time series behavior, spatial extent of storms, etc.

11. Selected Runs for Two Emissions Scenarios (A1b, B1)
GCM Run
Hybrid Delta 2020s
( )
Hybrid
Delta 2040s
Delta 2080s
Transient
( )
cnrm_cm3_A1B x
echam5_A1B
echo_g_A1B
hadcm_A1B
pcm1_A1B
ccsm3_A1B
cgcm3.1_t47_A1B
miroc_3.2_A1B
ipsl_cm4_A1B
hadgem1_A1B
[ Total of 76 Runs including Six Composite Delta Runs ]

12. Overview of Selected Basin-wide Products

13. Ratio of Peak SWE to Oct-Mar Precipitation

14. Change in Long-Term Mean April 1 SWE

15. Large-Scale Transformation of Watershed Characteristics

16. Historical and Projected 21st Century Flows for the A1b Scenario
Yakima River

17. Future Projections of Flood Risk
Floods in warmer areas of the basin are expected to increase in magnitude due to the combined effects of warming and increasingly intense winter storms.
In other parts of the basin, changes in flooding are smaller, and in strongly snowmelt dominant basins reductions in flood risk are common due to loss of spring snow cover.

18. Overview of Selected Site Specific Products

19. Locations of 297 Streamflow Simulation Points

25. Daily Streamflow Data (Hybrid Delta)

26. Reservoir Model Inflows
Specific bias adjusted products to support the following reservoir simulation models will be produced under funding for this project:
GENESYS (VIC)
Snake River basin simulation models (VIC)
ColSim model for the Columbia Mainstem (VIC)
Additional simulation products supported by HB 1303:
USBR Riverware model for the Yakima basin (VIC)
Seattle, Everett and Tacoma water supply systems (DHSVM)

27. Model Calibration

28. Calibration Watersheds

29. VIC Model Calibration Procedure
Task 2 - Calibrate VIC model and develop statistical bias correction procedures
VIC Model Calibration Procedure
Calibrate model to simulated streamflow by changing soil parameters (uncertainty in subsurface processes)
Compare simulated and historical streamflow using summary statistics
e.g. R2, Nash-Sutcliffe Efficiency, annual volume error
Use split sample calibration/validation approach
Utilize auto-calibration tool developed by U. of AZ

30. Net Monthly Mean Flow (units of 1000AF)
Yakima River at Parker
Net Monthly Mean Flow (units of 1000AF)
Naturalized Flow
Simulated Flow
Summary Statistics
R2: 0.88
N-S Efficiency: 0.71
Avg. Ann. Flow,
Sim/Nat: 1.08
Long-term Monthly Mean ( )