1. US Army Corps of Engineers BUILDING STRONG ® Weather, Runoff, and Water Quality Summary Water Year 2010 Steven B. Barton, P.E. Chief, Reservoir Control Center Northwestern Division 08 December 2010

2. BUILDING STRONG ® WY 2010 Precipitation Overall precipitation was near normal for much of the basin. Early fall precipitation was well above normal, deteriorating rapidly through the snow accumulation season. Normal precipitation returned in late spring with much above precipitation in June.

3. BUILDING STRONG ® WY 2010 Precipitation

4. BUILDING STRONG ® WY 2010 Precipitation

5. BUILDING STRONG ® WY 2010 Temperature Aside from an outbreak of arctic air in early December, winter temperatures were generally above normal. Spring temperatures began near normal, trending to below normal with accompanying precipitation in May and June. Summer temperatures were above normal in the Canadian upper Columbia southern portions of Idaho and Oregon, below normal in central Idaho, and near normal elsewhere.

6. BUILDING STRONG ® WY 2010 Temperature

7. BUILDING STRONG ® WY 2010 Temperature

8. BUILDING STRONG ® WY 2010 Water Supply and Runoff Rapid changes in weather relative to normal conditions were a challenge for forecasting water supply. Late spring precipitation increased late-season water supply forecasts by 4.0 MAF at Lower Granite, and 8.5 MAF at The Dalles. Seasonal runoff was generally below normal basin-wide.

9. BUILDING STRONG ® WY 2010 Water Supply and Runoff

10. BUILDING STRONG ® WY 2010 Water Supply and Runoff

11. BUILDING STRONG ® WY 2010 Water Supply and Runoff

12. BUILDING STRONG ® WY 2010 Water Supply and Runoff Peak unregulated discharge at The Dalles was 550 kcfs on June 7, 2010. Observed peak discharge at The Dalles was 393 kcfs on June 11, 2010.

13. BUILDING STRONG ® WY 2010 Water Supply and Runoff

14. BUILDING STRONG ® WY 2010 Water Supply and Runoff Priest Rapids spring flow objective was met. Objective = 135 kcfs Observed =138 kcfs McNary spring flow objective was met, but summer flow objective was not. Objective = 220 kcfs/200 kcfs (spring/summer) Observed = 226 kcfs (spring), 155 kcfs (summer) Lower Granite spring and summer flows fell just short of objectives. Objective = 85 kcfs/50 kcfs (spring/summer) Observed = 78 kcfs (spring), 47 kcfs (summer)

15. BUILDING STRONG ® WY 2010 Water Supply and Runoff

16. BUILDING STRONG ® WY 2010 Water Supply and Runoff

17. BUILDING STRONG ® WY 2010 Water Supply and Runoff

18. BUILDING STRONG ® Summary Comparison of TDG Instances Exceeding WQS - System Wide The 2010 TDG instances were slightly less than the 11-year average Water Quality - TDG

19. BUILDING STRONG ® Summary Comparison of TDG Instances Exceeding WQS - By FMS Water Quality - TDG

20. BUILDING STRONG ® TDG Instance Types Water Quality - TDG

21. BUILDING STRONG ® Summary Comparison of TDG Instances Exceeding WQS - By Type Water Quality - TDG

22. BUILDING STRONG ® Summary Comparison of Water Temperature Number of Days with 24-hour Average Over 68 o F Water Quality - Temperature