lake washington general investigation julie hall, seattle public utilities
Post on 27-Mar-2015
218 Views
Preview:
TRANSCRIPT
Lake Washington General InvestigationJulie Hall, Seattle Public Utilities
What I’d like to cover today…
• Study purpose
• History
• Accomplishments
• Status
• So what next?
LW GI PurposeIdentify 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.
History of the GI
1997:LW GI beganSeattle 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 formulationFeasibility analyses
Phase 2 =Seattle
Further studies
LW Chinook Habitat Use
LW Predators
Smolt Flume Efficiency
Locks Passage
Acoustic Tracking
Salmon Synthesis
Report
History of the GI
1997:LW GISeattle 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 formulationFeasibility analyses
Phase 2 =Seattle
Further studies
LW Chinook Habitat Use
LW Predators
Smolt Flume Efficiency
Locks Passage
Acoustic Tracking
Salmon Synthesis
Report
USFWS: Juvenile Chinook habitat use2000-2006
USFWS: Chinook smolt outmigration2005-2006
LW GI Studies
WDFW: LW and Ship Canal predators2000-2001, 2003
UW: Chinook habitat preferences2004-2005
USFWS: Dock observations2004-2006
USFWS: Chinook smolt outmigration2004-2008
WDFW/R2: Smolt Flume Efficiency2002, 2004
P.Johnson: Filling Culvert entrainment2000-2004
R2: PIT Tagging and Locks Passage1998-2008
Corps/MIT: Adult return timing/behavior2000, 2005-2007
Lake Washington
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
Density of juvenile Chinook, relative to distance from the Cedar River
March – June
y = -0.13Ln(x) + 0.33
R2 = 0.79
0
0.2
0.4
0.6
0 5 10 15 20
Distance to Cedar River
Den
sity
(fis
h/m
2 )
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
00.20.40.60.8
1
Ch
ino
ok
/ m2
Lake shore
Delta
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
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
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
Ship Canal and Lake Union
Tracking System
RECEIVER
1. “Listening station”
2. Get a fish and a tag
Tracking System
RECEIVER
3. Track your fish
Tracking System
Example Chinook smolt track from Portage Bay
Gas Works 2005
All Chinook combined into one density plot with each fish
weighted equally.
Gas Works 2005
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
Ballard Locks
Juvenile Salmon at the Locks Numerous projects and studies have occurred at the Locks to increase the safety of juvenile fish passage
Smolt slidesPit Tagging studies
Removing barnacles from the filling culverts
Operation of strobe lights to deter
smolts from entering the filling
culverts
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80 100 120 140 160 180 200
Total Daytime Flume Volume (cfs)
Rel
ativ
e G
uid
ance
Eff
icie
ncy
(%
)
May 8
May 9
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
Declining Detection Rates & Surface Water Temperature at the Fremont Bridge
0
50
100
150
200
250
300
350
400
450
11 13 15 17 19 21 23Mean Daily Water Temperature (C)
Nu
mb
er o
f P
IT T
agg
ed F
ish
Det
ecte
d/D
ay
2001
2002
2003
1.Synthesis report of research due end of 2008
2.Microacoustic tracking report due in 2009
Research Wrap-Up
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
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
top related