1. Lake Washington General Investigation Julie Hall, Seattle Public Utilities

2. What Id like to cover today… Study purpose History Accomplishments Status So what next?

3. LW GI Purpose Identify and implement environmental restoration projects for the Lake Washington system to: 1) improve habitat conditions for salmon and other wildlife; 2) use water efficiently at the Locks to benefit salmon.

4. History of the GI 1997: LW GI began Seattle and King County local sponsors Reconnaissance 1998: Reconnaissance report 905(b) Feasibility Split LW GI into 2 phases: 1999: Chinook listed 2006: Discontinued Phase 1 = King Co. Project formulation Feasibility analyses Phase 2 = Seattle Further studies LW Chinook Habitat Use LW Predators Smolt Flume Efficiency Locks Passage Acoustic Tracking Salmon Synthesis Report

5. History of the GI 1997: LW GI Seattle and King County local sponsors Reconnaissance 1998: Reconnaissance report 905(b) Feasibility Split LW GI into 2 phases: 1999: Chinook listed 2006: Discontinued Phase 1 = King Co. Project formulation Feasibility analyses Phase 2 = Seattle Further studies LW Chinook Habitat Use LW Predators Smolt Flume Efficiency Locks Passage Acoustic Tracking Salmon Synthesis Report

6. USFWS: Juvenile Chinook habitat use 2000-2006 USFWS: Chinook smolt outmigration 2005-2006 LW GI Studies WDFW: LW and Ship Canal predators 2000-2001, 2003 UW: Chinook habitat preferences 2004-2005 USFWS: Dock observations 2004-2006 USFWS: Chinook smolt outmigration 2004-2008 WDFW/R2: Smolt Flume Efficiency 2002, 2004 P.Johnson: Filling Culvert entrainment 2000-2004 R2: PIT Tagging and Locks Passage 1998-2008 Corps/MIT: Adult return timing/behavior 2000, 2005-2007

7. Lake Washington

8. Preferred rearing habitat includes: Shoreline areas with shallow depths (>1 m) and gentle slopes Fine substrates Overhanging vegetation/small woody debris Small creeks: mouths and shallow, low gradient, upstream portions Chinook fry need rearing habitat and rest stops for the 3-5 months they inhabit Lake Washington February-May

9. Density of juvenile Chinook, relative to distance from the Cedar River March – June

10. Small creek mouths = highly used Comparison of Deltas and Lake Shore (South L.Washington and L. Sammamish) From "Nearshore Habitat Use by Juvenile Chinook Salmon in Lentic Systems of the Lake Washington Basin". Annual Report, 2002 by Roger Tabor, US Fish and Wildlife Service

11. To Avoid Predators, Juvenile Chinook: Avoid areas with little light, like under docks Over-water structures cause juveniles to detour to deeper water Bulk heading and rip rap provide a refuge for predators, reduce shallow water areas, and prevent bank sloughing (which supplies fine sediment) Avoid shorelines without shallow water areas due to bank armoring

12. Docks affect how fish move along the shoreline Fish move in schools close to shore (within a few meters) After passing under or around the dock, the school moves closer to shore As the school approaches a dock, the fish move offshore into deeper water and pass under or around the dock Fish continue to move along the shoreline, close to shore May-June

13. direction of travel Effect of structures: Increase distance traveled Force migrating smolts into deeper water (increase predation risk?) Fish moved back to shallower water once beyond the last structure Microacoustic Tracking at Tennis Club

14. Ship Canal and Lake Union

15. Tracking System RECEIVER 1. Listening station

16. 2. Get a fish and a tag Tracking System

17. RECEIVER 3. Track your fish Tracking System

18. Example Chinook smolt track from Portage Bay

19. Gas Works 2005

20. All Chinook combined into one density plot with each fish weighted equally. Gas Works 2005

21. Acoustic Results Behavior very different between Lake Washington and the Ship Canal/Lake Union In Ship Canal, fish are widely distributed and not just along shoreline Chinook smolts use south Lake Union! Fish appear to spend longer periods of time in Lake Union (several days) Fish appear to hold/delay in Union Bay Predators associated with overwater structures, steep sloping shorelines, and edge of aquatic vegetation

22. Ballard Locks

23. Juvenile Salmon at the Locks Numerous projects and studies have occurred at the Locks to increase the safety of juvenile fish passage Smolt slides Pit Tagging studies Removing barnacles from the filling culverts Operation of strobe lights to deter smolts from entering the filling culverts

24. Fish Passage and Water Flow Studying the amount of water needed to pass the maximum number of smolts through the flumes At flows > 80cfs, > 95% of juvenile salmon used the flumes to pass through the Locks

25. Declining Detection Rates & Surface Water Temperature at the Fremont Bridge

26. 1.Synthesis report of research due end of 2008 2.Microacoustic tracking report due in 2009 Research Wrap-Up

27. LW GI Status – Both Phases Discontinued Seattle, similar to King County, discontinuing participation –Authority does not go away Reasoning: –Heavy staff and money investment in bureaucratic process –Uncertain future return –Reduced priority federally –Other avenues more cost-effective

28. So what is next? Other Corps partnership opportunities: –Section 206 –Section 1135 –Puget Sound and Adjacent Waters (PSAW) –Section 22 – Planning Assistance Salt water drain adult excluder Installed 6/08 Biological Opinion: Continuing and new actions at the Locks