Lake Washington General Investigation Julie Hall, Seattle Public Utilities

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Lake Washington General InvestigationJulie
Hall, Seattle Public Utilities
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What Id like to cover today

• Study purpose
• History
• Accomplishments
• Status
• So what next?

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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.
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History of the GI
1999 Chinook listed
Feasibility
Reconnaissance
Split LW GI into 2 phases
1997 LW GI began Seattle and King County local
sponsors
2006 Discontinued
Phase 1 King Co.
Project formulation Feasibility analyses
Salmon Synthesis Report
1998 Reconnaissance report 905(b)
Phase 2 Seattle
Further studies
LW Chinook Habitat Use
LW Predators
Smolt Flume Efficiency
Locks Passage
Acoustic Tracking
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History of the GI
1999 Chinook listed
Feasibility
Reconnaissance
Split LW GI into 2 phases
1997 LW GI Seattle and King County local
sponsors
2006 Discontinued
Phase 1 King Co.
Project formulation Feasibility analyses
Salmon Synthesis Report
1998 Reconnaissance report 905(b)
Phase 2 Seattle
Further studies
LW Chinook Habitat Use
LW Predators
Smolt Flume Efficiency
Locks Passage
Acoustic Tracking
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USFWS Chinook smolt outmigration 2004-2008
P.Johnson Filling Culvert entrainment 2000-2004
USFWS Chinook smolt outmigration 2005-2006
R2 PIT Tagging and Locks Passage 1998-2008
WDFW LW and Ship Canal predators 2000-2001, 2003
WDFW/R2 Smolt Flume Efficiency 2002, 2004
USFWS Dock observations 2004-2006
Corps/MIT Adult return timing/behavior 2000,
2005-2007
UW Chinook habitat preferences 2004-2005
LW GI Studies
USFWS Juvenile Chinook habitat use 2000-2006
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Lake Washington
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Chinook fry need rearing habitat and rest stops
for the 3-5 months they inhabit Lake Washington
February-May

• Preferred rearing habitat includes
• Shoreline areas with shallow depths (gt1 m) and
  gentle slopes
• Fine substrates
• Overhanging vegetation/small woody debris
• Small creeks mouths and shallow, low gradient,
  upstream portions

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Density of juvenile Chinook, relative to distance
from the Cedar River March June
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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
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To Avoid Predators, Juvenile Chinook
Avoid areas with little light, like under docks
Avoid shorelines without shallow water areas due
to bank armoring
Bulk heading and rip rap provide a refuge for
predators, reduce shallow water areas, and
prevent bank sloughing (which supplies fine
sediment)
Over-water structures cause juveniles to detour
to deeper water
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Docks affect how fish move along the shoreline
May-June
Fish continue to move along the shoreline, close
to shore
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 move in schools close to shore (within a few
meters)
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• 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
direction of travel
Microacoustic Tracking at Tennis Club
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Ship Canal and Lake Union
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Tracking System
1. Listening station
RECEIVER
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Tracking System
2. Get a fish and a tag
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Tracking System
3. Track your fish
RECEIVER
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Example Chinook smolt track from Portage Bay
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Gas Works 2005
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All Chinook combined into one density plot with
each fish weighted equally.
Gas Works 2005
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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

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Ballard Locks
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Juvenile Salmon at the Locks
Numerous projects and studies have occurred at
the Locks to increase the safety of juvenile fish
passage
Removing barnacles from the filling culverts
Operation of strobe lights to deter smolts from
entering the filling culverts
Smolt slides Pit Tagging studies
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Fish Passage and Water Flow
Studying the amount of water needed to pass the
maximum number of smolts through the flumes
At flows gt 80cfs, gt 95 of juvenile salmon used
the flumes to pass through the Locks
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Declining Detection Rates Surface Water
Temperature at the Fremont Bridge
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Research Wrap-Up

1. Synthesis report of research due end of 2008
2. Microacoustic tracking report due in 2009

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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

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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