1. International Osoyoos Lake Board of Control International Osoyoos Lake Board of Control Public Meeting Osoyoos Lake Water Science Forum October 8, 2015 Presented by Bruno Tassone, Chair, Canadian Section Marijke van Heeswijk, Secretary, U.S. Section Marijke van Heeswijk, Secretary, U.S. Section John Arterburn, Member, U.S. Section John Arterburn, Member, U.S. Section

2. United States Section Cynthia Barton, Chair U.S. Geological Survey John Arterburn Confederated Tribes of the Colville Res. Col. John Buck U.S. Army Corps of Engineers Kris Kauffman Water Rights, Inc. Ford Waterstrat Lake Osoyoos Association Osoyoos Lake Board of Control Canadian Section Bruno Tassone, Chair Environment Canada (retired) Glen Davidson B.C. Ministry of FLNRO Sue McKortoff Mayor, Town of Osoyoos Brian Symonds B.C. Ministry of FLNRO (retired) Anna Warwick-Sears Okanagan Basin Water Board Secretariat Secretariat Gwyn Graham Marijke van Heeswijk Environment Canada U.S. Geological Survey Gwyn Graham Marijke van Heeswijk Environment Canada U.S. Geological Survey

3. Expanded Board Membership Canadian Section –Sue McKortoff (Mayor, Town of Osoyoos) –Anna Warwick-Sears (Okanogan Basin Water Board) U.S. Section –John Arterburn (Confederated Tribes of the Colville Reservation) –Ford Waterstrat (Lake Osoyoos Association)

4. IJC and Osoyoos Lake Board of Control IJC issued Orders of Approval for managing Osoyoos Lake levels (1946, 1978, 1982, 1985, 2013) Lake levels are generally regulated by Zosel Dam, located near Oroville, Wash. IJC appointed Osoyoos Lake Board of Control to monitor provisions of the Orders Current Zosel Dam, constructed in 1987 near site of original dam (constructed in 1927)

5. Osoyoos Lake Rule Curve

6. Okanagan/Okanogan & Similkameen River Watersheds Similkameen R. Okanagan R. Columbia R. Okanogan R. Columbia R. Osoyoos Lake Okanagan Lake Dam

7. Diagram of System Okanagan Lake Skaha Lake Vaseux Lake Osoyoos Lake Similkameen River CANADA General streamflow Transborder-collaboration points for system operations Minor Dam US Okanagan Lake Regulation System (OLRS) Okanogan River Zosel Dam Major Dam Other Streamflow

8. Hydrologic Conditions in 2015 The year of the double whammy Below average snowpack accumulation followed by a warm and dry spring and summer

9. March 1, 2015 April 1, 2015

10. 1 2 3 Snow Pillow Number Peak Snowpack Accumulation (% of average) Timing of Snowmelt Initiation (# weeks early) Timing of Snowmelt Completion (# weeks early) 17004 27554 38003 1. Blackwall Peak 2. Brenda Mines 3. Mission Creek

11. Okanagan Lake Water-Surface Levels JanJulAugSep Apr MayJun FebMar 2015 peak: 1,123.31 ft, June 5-6 Average peak: 1,123.20 ft, June 28-29 2015 Average (1944-2014, 71 yrs) Drought criterion: 1,122.6 ft 2015 record includes provisional data

12. Monthly Net Inflows to Okanagan Lake

13. Okanagan River at Oliver (inflows to Osoyoos Lake) JanJulAugSep Apr MayJun FebMar 2015 Average (1944-2014, 71 yrs) 2015 record includes provisional data

14. Similkameen River at Nighthawk (confluence downstream from Zosel Dam) Jan JulAugSep Apr MayJun FebMar 2015 Average (1929-2014, 86 yrs) WWWwWWWw 2015 record includes provisional data Minimum (1929-2014)

15. Order of Approval, Section 8: Drought Criteria Not Met in 2015 Criteria for Declaring a Drought Forecasted Early April Forecasted Early May Actual Value Drought Criterion Met? Significance a) April-July flow volume in the Similkameen River is less than 1 million ac-ft 1.039 million ac-ft 0.831 million ac-ft 0.820 million ac-ft No Yes Required for drought declaration b) i) April-July net inflow to Okanagan Lake is less than 195,000 ac-ft 396,000 ac-ft 316,200 ac-ft 199,100 ac-ft No One of these two required for drought declaration ii) June or July maximum level of Okanagan Lake is less than 1,122.6 feet >1,122.6 ft by mid-April 1,123.3 ft No

16. Drought Determinations by Entity 16 DateOsoyoos Lake Board of ControlWashington StateBritish Columbia April 14Notifies Washington State that drought conditions are not in effect according to criteria defined in the IJC Order April 17Expands limited drought declaration to include the Okanogan Basin July 10Declares level 3 drought for the Okanagan Basin July 28Notifies Washington State that IJC approved a variance according to Condition 10 of the Order that allows Zosel Dam operation in compliance with the drought- condition rule curve for the remainder of 2015

17. No Deviations from the Rule Curve in 2015

18. Hydrologic Forecast for 2015-16 A strong El Niño is expected into spring 2016 It is on track to be ranked #3 since 1950, after 1997 (#1) and 1987 (#2) Most likely result: 1) PNW will be warmer 2) PNW precipitation may be normal, but likely below normal east of Cascade Range

19. Initiatives in 2015 In September, the IJC funded the Board’s IWI proposal for an educational documentary Purpose: engage residents of the watershed and show how the system is managed to balance multiple needs Lead agency is Washington State Dept. of Ecology Request for Osoyoos Lake photos for website! (Details at http://ijc.org/en_/iolbc/Activities)

20. Questions? Next speaker: John Arterburn

21. What follows are slides that will not be used during the presentation, unless necessary.

22. Snow Pillows 1. Blackwall Peak 2. Brenda Mines 3. Mission Creek 1 2 3

23. 1. Blackwall Peak Snow Pillow (Similkameen R. basin) Average Maximum Minimum 2014/15

24. 2. Brenda Mines Snow Pillow (Okanagan R. basin) Average Maximum Minimum 2014/15

25. 3. Mission Creek Snow Pillow (Okanagan R. basin) Average Maximum Minimum 2014/15