1. Stockholm Environment Institute Natural Heritage Institute CABY Watershed Modeling with WEAP CABY Planning Meeting May 6 2006 David Purkey and David Yates

2. Application of WEAP to the American River Basin

3. Catchment Delineation Based on six digit hydrologic units (HUC6). HUCs were subdivided if necessary to calculate inflows to key reservoirs. In addition to 56 catchments in the American River Basin, the Camp Creek and Sly Park Creek catchments were added to compute inflow to Jenkinson Lake.

4. American River Basin

5. Major Streams in Basin

6. Model Catchments

7. Catchment Characterization Land was categorized using the SSURGO soils and the CALVEG vegetation databases. –Soils were classified as shallow or deep. –Vegetation was classified as trees, shrubs, bare, urban, grassland, or wet. Resulting classifications were –Deep trees –Shallow trees –Deep shrubs –Etc.

8. Modeled Rivers

9. Modeled Reservoirs Aloha Hell Hole Loon Lake Echo French Meadows Caples & Silver Folsom Union Valley Ice House Sly Park Stumpy Mdw

10. Modeled Transfers

11. Climate Data DAYMET.org (Univ. Montana & NCAR) –Daily, 1-km gridded data were mapped o the centroids of each suib-catchment –Precipitation, temperature, humidity, and wind. Data were developed using observed climate data and terrain models.

12. Effect of Elevation on Temperature and Precipitation

13. System Operations

14. Middle Fork Project Operations Upper American River Project El Dorado Irrigation District

15. Middle Fork Project

16. Middle Fork Project Operations Logic Minimum flow requirements are based on Article 37 of the current FERC license. Reservoir minimum pool values are based on Article 36 of the current FERC license. Reservoir guide curves are average monthly storage values from 1980 - 2005 –Min pool and min flows are a function of April 1 predicted WY Folsom inflow. –In effect June 1 – May 31.

17. Upper American River Project

18. Upper American Project

19. Upper American River Project Operations Logic Minimum flows are based on current FERC license. Reservoir critical and typical year rule curves were taken from Exhibit B of license application. –Both are a function of April 1 predicted WY Folsom inflow. –In effect April 1 – March 31.

20. EID Operations

21. El Dorado Irrigation District

22. EID Operations Logic Demands were taken from the Shared Vision Model. –Project 184 only demands. –Project 184 or Sly Park demands Served by Sly Park if storage is greater than 38,000 af –Sly Park only demands –Folsom or Sly Park demands Served by Sly Park if storage is greater than 38,000 af –Folsom only demand Model currently has Silver and Caples Lakes. Echo Lakes are represented by a inflow.

23. April 1 Predicted Water Year Inflows to Folsom Reservoir

24. Folsom Inflow Prediction Department of Water Resources has developed a regression equation: Inflow (TAF) = 0.2507 X 2 + 57.99 X – 962 X = average observed rainfall (Oct – Mar) + average historical rainfall (Apr – Sep) (inches)

25. X – Avg. Observed Rainfall Average observed rainfall is calculated using observations from Blue Canyon, Pacific House, Foresthill Ranger Station, Georgetown, Colfax, and Placerville. In the model we use predicted rainfall from the corresponding catchments.

27. Modeled vs. DWR Water Year Folsom Inflows 81 - 99

28. Calibration Results

29. North Fork American at North Fork Dam

30. Upper Duncan

31. Caples Lake SWE

32. Upper Rubicon

33. Union Valley Natural Inflow

34. Soil Moisture at Blodgett F.R.S

35. Middle Fork American at Foresthill

36. South Fork American At Placerville

37. American River Inflows to Folsom

38. Climate Change (and other) Scenarios in WEAP

39. Wood, et al. 2002, ‘Long range experimental hydrologic forecasting for the eastern U.S.’, J. Geophys. Res. 107(D20). Jan, Feb.. Dec. 1960-1990 Bias Correction Obs 2 o GCM hist d p,t dp’=dp*d p dt’=dt+d t dp=p 2xCO2 /p Hist dt=t 2xCO2 -t Hist Climate Scenarios- Downscaling hist cc p,t t p cc =p hist *dp’ t cc =t hist +dt’ Spatial downscale Map back to obs

40. Probabilistic assessment of regional climate change A Bayesian approach that combines predictions from multiple AOGCM output (21 models) Probabilistic representation of temperature/precipitation change, at regional scales, incorporating natural variability Reconciles projections from different AOGCMs BIAS and CONVERGENCE criteria: Reward models that perform well in reproducing current climate/ discount models that show a large bias Reward models that form a consensus/downweight extreme Projections Avoids the Problems of being “Married” to individual GCM!!

41. Climate Scenarios- Probabilistic Projections A1B Seasonal Changes for Northern California from 21 AOGCMs Precipitation WinterSpringSummerFall Winter- equal likelihood of more or less precip.; no strong long term trend Spring, Summer Fall- more likelihood of less precip.

42. Climate Scenarios- Probabilistic Projections Temperature WinterSpringSummerFall A1B Seasonal Changes for Northern California from 21 AOGCMs Early 21 st Century warming of 0.8C Natural variability could mask early 21 st century anthropogenic warming.

43. Climate Scenarios - Probabilistic Projections These probabilistic projections are useful, for getting a “feel” for the climatic range suggested by AOGCM models. BUT.. How do we use this information given impact assessment needs? Impact assessment models need “REAL DATA”.. E.g. Climate time series, such as temperature, precipitation, wind, humidity, etc. This is the downscaling process…

44. Climate Scenarios - Probabilistic Projections K-Nearest Neighbor Downscaling Hist Avg PcpHist Avg. Tmp Yates et al. 2003, A K-nn algorithm for generating regional climate scenarios, WRR

45. Climate Scenarios- Probabilistic Projections WmDry 1 WmDry 5 WmWet 1 WmWet 5 historic Monthly Avg. Temperature for Alder Creek - 2010 to 2030 C

46. Climate Scenarios- Probabilistic Projections WmDry 1 WmDry 5 WmWet 1 WmWet 5 historic Monthly Total Precipitation Data for Alder Creek – 2010 to 2030 mm

47. North and Middle Forks French Meadows Hell Hole

48. cms Runoff North Fork American historic

50. Climate Change and Hydropower for the main projects An ensemble of climate projections and their impacts on hydropower Gw-hrs Headline: Even Wet scenarios suggest a decline in production with given operating rules.

51. Project Storage

52. North Fork Water Temps- Unmanaged Watershed WARM Dry WARM Very Dry

53. Middle Fork Water Temps – Managed Watershed WARM Dry WARM Very Dry

56. 2020-2024 1996-2000 Caples SWE

57. 2020-2024 1996-2000 Upper Rubicon Streamflow

58. 2020-2024 1996-2000 Loon Lake Storage