Has Idaho Bitten Off More Than It Can Chew? Climate Change Impacts in the Snake River Basin

1. Has Idaho Bitten Off More Than It Can Chew?Climate Change Impacts in the Snake River Basin CIG Seminar - May 27, 2004 Nathan VanRheenen and Richard N. Palmer Dept. of Civil and Environmental Engineering -University of Washington- www.tag.washington.edu

2. Politically Incorrect Title: Future Streamflow Scenarios and System Management in the Face of: • Dwindling fish stocks • Thirsty farmers • Demanding energy users • Effective lobbyists • Government “solutions” • Climate change • Tragically slow decision-making processes

3. In the beginning … Colsim, Alan Hamlet • Developed to investigate climate change impacts on Columbia River Basin water resources • Fish, Power, Irrigation, M&I • Very effective for Col R main stem • Major Drawback • Snake River Basin inadequately represented • Most significant tributary • 427 TAF Flow Aug. rule • Our Goal (Palmer, Lettenmaier, VanRheenen, Hamlet) • Develop a well-represented Snake River model of similar scale and usefulness of Colsim

4. Goals of Research • What are the long-range impacts of climate change on the managed system? • Goal: Develop a model that incorporates current and future operating rules and management strategies • Simulation Model of Snake River Basin (SnakeSim) • How can the potential impacts of climate change be mitigated? • Goal: Develop a model that provides the “best” management strategy for SRB users • Optimization Model of SRB (SnakeOpt)

5. Background – Snake River Basin • Snake River – 1000 miles long • 20 major reservoirs • 14 MAF storage • 17 MAF demands/water rights • 700 MW hydropower capacity • Brief history

7. Snake River Basin to Brownlee

8. Snake River Plain Aquifer

9. Political Landscape • Many users • Many opinions • Scientific controversy • Established positions • Political activism

10. Political Landscape • No More Ignoring the Obvious – Idaho Sucks Itself Dry – HCN, 2/95 • “The department has handed out water rights and groundwater permits as if there’s no tomorrow." • "The fish were there first, but they didn’t fill out the (water rights) forms."

11. Political Landscape • 1995 – BOR agrees to provide 427 TAF/yr for flow augmentation • Goal likely to be met 80% of years • Irrigation shortages that result • 72 TAF in ave years, 335 TAF in dry years • 427 TAF goal unmet in last 3 yrs due to drought “Flow augmentation is a failed experiment that has been scientifically discredited and should be dropped.” - Water Coalition President, Oct 2003

12. Political Landscape • Snake River water right moratorium ends, but permits will not be processed – DOE, 7/99 • To Breach or Not to Breach – HCN, 2/00 • Salmon Plan Calls for Sacrifices, Federal Remedies Contain Something for All Sides to Criticize – SSR, 7/00 • Dredging Plans Stall on the Snake River– HCN, 3/03 • Andrus says Dams a Problem, but Breaching is Impractical– SSR, 9/03 • Calls for “Dramatically revamping river management policies”

13. Political Landscape • Advocates file suit to help protect fish – SSR, 1/17/04 • Fish Lobby: “Operation of the bureau's upper Snake projects has a profound impact on the survival of Snake River salmon, and even affects fish downstream in the Columbia.” • Water Coalition Lobby: “It's an unfortunate reality that they're fixated on trying to secure Idaho water and send it downriver for a failed experiment.”

14. Political Landscape • Snake River Basin Adjudication • May 15, 2004 - ID, BOR reach agreement with Nez Perce after 10 years of negotiations • Agreement • Tribe • 50 taf water right for tribal lands, dated 1855 • $23M for new sewer and water system • $50M trust for land/water acquisition + $7M land • 200 taf of Dworshak storage for summer flow aug  427 taf Flow Augmentation Rule nearly “guaranteed”

15. Snake River Models

16. Changes in Mean Temperature and Precipitation or Bias Corrected Output from GCMs SnakeSim VIC Hydrology Model SnakeOpt

17. PNW Climate Change Scenarios ~ + 1.7 C ~ + 2.5 C Somewhat wetter winters and perhaps somewhat dryer summers

18. Snake System Flows – Jackson Lk

19. Snake System Flows – Milner

20. Snake System Flows – Boise/Payette

21. Snake System Flows – Dworshak R.

22. Snake System Flows – Clarkston

23. Overall Streamflow Trends - comp2020

24. SnakeSim Operations Model

25. SnakeSim Operations Model • Purpose: Measure the projected impacts of climate change on SRB water resources • Considers • Major surface water features • Accepted management practices/rules • System uses • e.g., flood control, irrigation, fish, hydropower • Groundwater/Surface water interactions

26. SnakeSim – Upper Snake Storage

27. SnakeSim – Middle Snake Storage

28. SnakeSim – Boise/Payette Storage

29. SnakeSim – Dworshak Storage

30. SnakeSim – Snake System Storage

31. Overall Storage Trends - comp2020

32. SnakeSim – Groundwater Response • Recharge/discharge change as irrigation patterns change • Decreases in irrigation result in decreases in recharge and discharge • BOR estimates SRPA elev decreases 40 feet in next 50 years due to irrig. restrictions • Impacts of mgmt likely far greater than impacts of climate change on gw

33. Snake River Plain Aquifer

34. SnakeSim – Implications • Nature of flow shifts due to climate change are significant… • Water quality and fish implications • System operations implications • Need to investigate impacts on water rights system and conjunctive uses • Managed recharge as a cc mitigation strategy • But, “best” mitigation techniques aren’t known

35. SnakeOpt • Purpose: Develop a model that provides the “best” management strategy for SRB users • Considers • Major surface water features • System uses • e.g., flood control, irrigation, fish, hydropower • Groundwater impacts • 5 Major Irrigation Districts • Economic Objective Function

37. SnakeOpt - Approach • LP/SLP Decomposition • Objective Function • 5-year Model • Maximize Z = Flood control benefit + Environ. benefit + Farming profit + Hydropower profit • Subject to • Inflows, PET, Precip, Crop values and costs, Energy demand, Groundwater

38. SnakeOpt - Approach • LP/SLP Decomposition • Objective Function • 1-year Model • Redefine constraints with 5-year model month 12 conditions • Add value judgments to obj fn components

39. SnakeOpt - Approach 2 Applications • Long-Range Planning • 20-40 yrs to planning horizon • Evaluate long-term optimal system operation strategies • Annual Planning • Given 3-5 year forecast and predicted ENSO/PDO states • How much water can irrigators, utilities, and fish get in the next year to ensure a sustainable future?

40. SnakeOpt – 1st Cut (no hydropower) 427 TAF met

41. SnakeOpt - Demonstration • No hydropower due to running SLP time • No flood control costs/benefits • Loose Flow/Storage constraints • No environmental costs/benefits • Min flow target constraints

42. Integrated SnakeSim/SnakeOpt Framework • Purpose • To test optimal management strategies in the simulated system and evaluate their “true” effectiveness • Approach • Perform rigorous sensitivity analysis in SnakeSim around optimal values to generate tradeoff curves for management

43. Integrated SnakeSim/SnakeOpt Framework • Preliminary feedback from IDWR as to the general approach and purpose • “Potentially of tremendous value” • Allow first glimpses into impacts of “shifting uses” • Adaptation of approach to other regional water suppliers

44. SRB Modeling Effort - Horizon • End June • Complete SnakeOpt and integrated SnakeSim/SnakeOpt model • Mid June • Incorporate 85-year streamflows into SnakeSim and SnakeOpt • Improved ET calculation • June, July • Interview ID water users for value judgment data • Meet with IDWR to discuss results, etc.