HomeMy WebLinkAboutLake StudyLAKE STUDY
Southport Shoreline Modifications
Prepared for: SECO Development Inc.
Prepared on behalf of: Greg Krape, SECO Development, Inc.
August 2016
THE
WATERSHED
COMPANY
Printed on 30% recycled paper.
L AKE S TUDY
Southport Shoreline Modifications
Prepared for:
Greg Krape
SECO Development, Inc.
1083 Lake Washington Blvd. N, Suite 50
Renton, WA 98056
Prepared by:
August 2016
The Watershed Company
Reference Number:
150809
The Watershed Company Contact Person:
Andy Noone
Cite this document as:
The Watershed Company. August 2016. Lake Study. Southport Shoreline
Modifications, Renton, WA. Prepared for SECO Development, Renton, WA.
i
TABLE OF C ONTENTS
Page #
1 Introduction ......................................................... 1
1.1 Background and Purpose ............................................................................. 1
2 Existing Conditions and Ecological Functions 2
2.1 Description of Project Area ........................................................................... 2 2.2 Critical Areas and Habitat ............................................................................. 7
3 Local Regulations ............................................... 9
4 Project Description ........................................... 10
4.1 Proposed Shoreline Modifications ............................................................. 10
4.2 Project Purpose ........................................................................................... 11
5 Analysis of Alternatives ................................... 11
6 Impact Evaluation & Functional Lift Analysis 12
7 Best Available Science ..................................... 15
7.1 Habitat .......................................................................................................... 15 7.2 Overwater Cover .......................................................................................... 15
7.3 Lighting ........................................................................................................ 16
7.4 Water Quality (substrate disturbance and discharge of waste products) 16
8 Summary ............................................................ 17
References ............................................................. 18
Appendix A: Southport Shoreline Modifcations Site Plan
L IST OF E XHIBITS
Figure 1. Vicinity map from King County iMAP (Electronic reference) ............................ 1 Figure 2. Aerial view of proposed project parcels (outlined in yellow) from City of Renton
COR Maps (Electronic reference). .......................................................... 2
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Figure 3. Looking northeast near the center of the bulkhead. Note the existing bulkhead, piles, waler, and sheet piles to be removed/repaired. ............................... 3
Figure 4. Looking southwest from the pier in the northeast corner. Note the existing
bulkhead, piles, and waler to be removed/repaired. ................................. 4 Figure 5. Looking north near the western area of the bulkhead. This is the approximate
location of the western proposed float. ..................................................... 4 Figure 6. Looking east from the western pier adjacent to Boeing. The western float is proposed in the right hand area of the photo, and the eastern float is
proposed adjacent and parallel to the distant bulkhead on the left of the photo. ....................................................................................................... 5 Figure 7. Looking northeast from the eastern walkway. .................................................. 5
Figure 8. Detail of timber waler, pile, timber spacer, sheet pile and anchor. Note the rotted condition of the timber sheet pile closest to the concrete bulkhead.6
Figure 9. Dolphin and finger pier in center of photo is proposed for removal. ................. 6
Figure 10. Dolphin in center of photo is proposed for removal. ........................................ 7 Figure 11: A turtle was observed on site by Kenny Booth, Senior Planner. The turtle
appears to be an invasive red-eared slider (photo taken August 10th,
2015) ........................................................................................................ 9
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L AKE S TUDY
SOUTHPORT S HORELINE M ODIFICATIONS
1 INTRODUCTION
1.1 Background and Purpose
The purpose of this report is to document potential critical area impacts associated
with proposed shoreline modifications at the Southport site, located on the
shoreline of Lake Washington in the City of Renton, Washington (Figures 1 and 2).
The property is located at 1083 Lake Washington Blvd N, Renton, Washington
98055 (SW ¼ of Section 05, Township 23 North, Range 5 East; 47.503467 N
Latitude, -122.205303 W Longitude; Figures 1 & 2). The tax parcel numbers
associated with this project are: 0823059216, 0523059075, and 0523059076. The
project area falls within the Lake Washington/Cedar/Sammamish Water Resource
Management Area (WRIA 8).
Figure 1. Vicinity map from King County iMAP (Electronic reference)
Project Site
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Figure 2. Aerial view of proposed project parcels (outlined in yellow) from City of Renton
COR Maps (Electronic reference).
The Southport development includes the Bristol I and II apartment buildings
(completed), a hotel (under construction), and a 3-building office and parking
garage complex (soon to be under construction). Previous Shoreline Substantial
Development Permits include the Southport Level 2 Site Plan in 2000 (Ecology
filing date May 3, 2000; SDP #2000-NW-40003); decking over the water discharge
tunnel in 2006 (LUA-06-033, SM); and modifications to the master plan in 2008
(LUA-99-1889, SA-A, SM) and again in 2014 (LUA 14-000645,SA-A, AM, MOD,
MOD). A Shoreline Conditional Use Permit for a mixed-use development (Bristol
I) was approved in 2001 (LUA01-057, CU-H). Previous shoreline permits did not
include the improvements proposed at this time.
Shoreline modifications are now proposed to repair the existing bulkhead,
improve in-water ecological conditions, accommodate temporary moorage of
motorized and non-motorized vessels, and allow for expanded recreational use of
the shoreline.
Lake Washington is considered a critical area by the City of Renton. Renton
Municipal Code (RMC) 4-3-050-F-2(c) requires that a lake study be conducted as
part of any modification to a lake critical area. This report fulfills this
requirement.
2 EXISTING CONDITIONS AND
ECOLOGICAL FUNCTIONS
2.1 Description of Project Area
The site is located in the City of Renton on Lake Washington, between Gene
Coulon Memorial Beach Park and the Boeing manufacturing facility. The site is
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zoned Urban Center and designated as a High Intensity environment under the
Renton Shoreline Master Program.
The existing shoreline is entirely bulkheaded. Upland conditions within the
subject parcels adjacent to the waterfront are almost exclusively impervious
(90%+), either concrete or pavers. The central shoreline area ten feet upland of
the bulkhead includes a pedestrian easement (Recording Nos. 2005102100894,
20051021000895, and 20051021000896) and an emergency vehicle access
easement. The easternmost 53 feet of the central waterfront is vegetated with a
mix of non-native landscape plants and non-native invasive species such as
Himalayan blackberry.
Existing depths along the bulkhead in the central and western shoreline areas
range from 8 feet to 17 feet.
Figure 3. Looking northeast near the center of the bulkhead. Note the existing bulkhead, piles, waler, and sheet piles to be removed/repaired.
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Figure 4. Looking southwest from the pier in the northeast corner. Note the existing bulkhead, piles, and waler to be removed/repaired.
Figure 5. Looking north near the western area of the bulkhead. This is the approximate location of the western proposed float.
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Figure 6. Looking east from the western pier adjacent to Boeing. The western float is
proposed in the right hand area of the photo, and the eastern float is proposed adjacent and parallel to the distant bulkhead on the left of the photo.
Figure 7. Looking northeast from the eastern walkway.
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Figure 8. Detail of timber waler, pile, timber spacer, sheet pile and anchor. Note the rotted condition of the timber sheet pile closest to the concrete bulkhead.
Figure 9. Dolphin and finger pier in center of photo is proposed for removal.
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Figure 10. Dolphin in center of photo is proposed for removal.
2.2 Critical Areas and Habitat
Lake Washington
Lake Washington is a 33.8 square mile freshwater lake. It is the second largest
lake in the State of Washington. Adult and juvenile Chinook salmon and
steelhead trout (listed as Threatened under the Federal Endangered Species Act)
migrate through Lake Washington. Adults migrate upstream to reach spawning
grounds in local tributaries; juveniles migrate downstream from their natal
streams to reach the ocean. Coho salmon also migrate through Lake Washington
(Species of Concern under the Federal Endangered Species Act). Bull trout, listed
as Threatened under the Federal Endangered Species Act, may also migrate
through Lake Washington. Lake Washington is a Shoreline of Statewide
Significance and is classified as a Type-S waterbody.
Wetlands and Streams
No wetlands or streams were noted within the immediate vicinity of the project
area, nor do publicly available data indicate the presence of aquatic areas aside
from Lake Washington.
Habitat
Habitat structure on the property is virtually non-existent, with no native
vegetation present along the shoreline in the project area. The majority of the area
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immediately upland of the bulkhead is covered with impervious surfaces. Several
invasive species are present on site including Himalayan blackberry and reed
canary grass. The lack of structural diversity limits food and cover opportunities
for most wildlife species, including songbirds and small mammals. The lack of
shoreline vegetation also limits cover opportunities for fish and allocthonous
inputs into the lake.
Soils
According to the Natural Resources Conservation Service, the property contains
Urban land (Ur) soils.
Wildlife
Washington Department of Fish and Wildlife Priority Habitats and Species
database lists two bald eagle nests within one mile of the project site.
Additionally, osprey presence is documented less than a half mile from the project
site. These large birds of prey typically nest and feed over large bodies of open
water and will likely fly over the project site. Great blue herons are widespread in
western Washington. Outside of breeding, which occurs in tall trees, commonly
away from human disturbance, the birds are most often observed in and along
rivers, lakes, and wetlands. The waters of Lake Washington are likely used by
foraging and resting herons throughout the year.
A turtle was observed on site by Kenny Booth, Senior Planner on August 10th,
2015. The turtle appeared to be a red-eared slider, a non-native species. There are
only two native turtle species in Washington, the western painted turtle and the
western pond turtle. Historically, western pond turtles inhabited Lake
Washington, but they have been extirpated from the area for a number of years,
likely due to development pressures, diminished water quality, and/or
competition from introduced turtle species. The western painted turtle may still
occur in Lake Washington but is also being displaced by introduced invasive
species such as the red-eared slider. Two other introduced species have also been
observed in Lake Washington: snapping turtles and spiny soft shell turtles.
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Figure 11: A turtle was observed on site by Kenny Booth, Senior Planner. The turtle
appears to be an invasive red-eared slider (photo taken August 10th, 2015)
Since the project site is mostly hardscape surfaces, vegetative habitat is limited,
and it is unlikely that terrestrial wildlife use the site. Small birds may fly over the
site in order to reach the adjacent to 57-acre Gene Coulon Memorial Beach Park,
which, while heavily landscaped, provides significantly more habitat value than
the project site.
3 LOCAL REGULATIONS
In Renton, shoreline areas are governed by the Shoreline Master Program and
regulated specifically by RMC 4-3-090. Lake Washington is a Shoreline of
Statewide Significance.
As mentioned, RMC 4-3-050-F-2(c) requires that a lake study be conducted as
part of any modification to a lake critical area. The required lake study must
demonstrate that the proposed modifications result in no net loss, meaning the
applicant must demonstrate that the modifications, combined with any
mitigation efforts, will result in equivalent or better protection of shoreline
functions.
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Mitigation or restoration of the critical area may involve restoring the shoreline
by removing structures or impervious surfaces, removing invasive plant species,
and/or planting native vegetation along the shoreline.
4 PROJECT DESCRIPTION
4.1 Proposed Shoreline Modifications
SECO Development proposes the following improvements to the shoreline area
at the Southport site (see attached plan set for additional details):
Eastern shoreline
A fully-grated ramp and float is proposed on the eastern shoreline. The eastern
float will feature two ells for added recreational boat access. The float and ramp
will total 2,013 square feet. Proposed work along the eastern shoreline also
includes abandoning the recently removed 164-foot-long floating walkway
referred to as a “log boom”. The log boom was removed several years ago and
will not be restored as part of this project. In addition, existing invasive species
located in the northeast corner of the project area will be removed.
Central shoreline
Significant repairs are proposed for the bulkhead and timber pilings along the
central shoreline. The proposed repairs involve the following: the outermost row
of rounded timber piles supporting the bulkhead will be removed
(approximately 20). The inner row of rounded timber piles supporting the
bulkhead will be cut below the low water line and fitted with a steel sleeve. In
some areas, piles are missing in this inner row of rounded timber piles. Where
missing piles are encountered, new 8-inch diameter steel piles will be driven. A
new timber waler will be added to the waterward side of the steel sleeved pile.
Existing anchors will be reconnected or replaced, as needed. The inner timber
sheet pile will be cut below the low water line. A steel plate will be driven along
the waterward edge of the timber sheet pile and bolted to the remaining portion
of the timber sheet pile. The area behind the steel plate will be filled with
concrete. The outer steel-sleeved pile and steel plate will extend vertically above
the high water mark and will support a new grated apron. The apron will be
flush with the adjacent sidewalk and will cover remaining exposed bulkhead
components. There will be two sections of apron, on either side of the deck,
extending 220 feet and 155 feet. The apron will be approximately 3.5 feet wide,
resulting in approximately 1,312 square feet of fully-grated over-water coverage.
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Other proposed modifications within the central shoreline include removal of the
following: up to 101 derelict pilings, 290 feet of 12-inch by 14-inch horizontal
dimensional beams, several drifted logs resting against bulkhead, and all anchor
and link logs from the log boom western attachment piling.
Western shoreline
The western shoreline modifications include installation of a pump out facility at
the existing wharf, and installation of a second, fully-grated ramp and float
totaling 528 square feet. As mitigation, the proposed modifications include
removal of 2 dolphins (each comprised of 7 piles), 1 finger pier (5-feet-wide by
17-feet-long), removal of a 10-foot-wide by 14-foot-long ell end dock, and
abandonment of a second recently removed finger pier that was also 5-feet-wide
by 17-feet-long.
4.2 Project Purpose
The purpose of the proposed project is to repair the deteriorating bulkhead. The
bulkhead has been assessed by an engineer and it has been determined that for
the bulkhead to last another 30-50 years, it must be repaired. The bulkhead
supports the existing walkway/promenade, which is adjacent to the existing
apartments and hotel under construction. In addition to needing structural
repairs, the existing bulkhead system is unsafe. As mentioned, multiple
rounded-piles and sheet-piles are located waterward of the concrete portion of
the bulkhead. Many of these components are located just below the OHWM and
can’t be seen at all times from shore. This project seeks to enhance safety by
providing an apron over the remaining (and functionally necessary) in-water
components. The apron will ensure that should someone fall or dive from the
promenade/walkway, they would not strike any in-water piles or other
structural components.
The proposed floats are intended to provide public access opportunities for
primarily non-motorized watercraft. As mentioned, the site includes four mixed-
use apartment buildings, with a hotel and multiple office buildings now under
construction. Thus, demand for access to the water will increase greatly. The
floats will allow for residents of the site and hotel guests to utilize kayaks,
canoes, or other non-motorized vessels. This will result in an increase in direct
public access to the shoreline.
5 ANALYSIS OF ALTERNATIVES
Pursuant to RMC 4-9-050-L(1)(b), attempts to avoid and minimize, and rectify
impacts to the on-site shoreline critical area have been taken.
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Avoidance: Shoreline improvements are necessary to avoid future bulkhead
failure and provide adequate water access. An alternative location for the project
is not feasible, as the project is intended to ensure structural stability for the
shoreline and to provide shoreline access for residents, guests, and tenants at the
SECO site.
Minimization: Minimization techniques were utilized during the design process
in order to limit impacts to the shoreline critical area. Minimization measures
included providing shoreline access via anchored floats, rather than docks on
pilings; reducing the size of the two floats to the minimum necessary; and fully
grating the floats to allow light to pass through. Instead of removing and
reinstalling the entire bulkhead, repairs to the existing bulkhead are proposed to
reduce impacts. Where possible, existing piles and other materials that support
the bulkhead will be reused and/or capped, instead of removed and replaced.
Rectifying/Mitigation: Mitigation includes the removal of 87 derelict creosote
piles, approximately 20 piles associated with bulkhead repairs, two additional
dolphins each comprised of seven piles, one finger pier (5-feet-wide by 17-feet-
long), and one ell dock (10-feet-wide by 14-feet-long). In addition to removing
these docks and creosote pilings, the project will also involve abandoning a
second 10-foot-wide by 17-foot-long finger pier, abandoning the recently
removed 164-foot long floating walkway, removing all anchor and link logs
associated with that floating walkway, and removing several drift logs resting
against the bulkhead. The project will also involve controlling invasive species
within the shoreline area, particularly Himalayan blackberry. Overall removal
includes 225 square feet of existing pier area, and approximately 121 creosote
pilings.
6 IMPACT EVALUATION & FUNCTIONAL
LIFT ANALYSIS
The project involves improvements to the shoreline bulkhead, installation of two
new floats, and removal of multiple in-water and over-water components.
Overall the proposed impact has been minimized to the greatest extent feasible in
that anchored, fully-grated floats were chosen over piers. The grating allows light
to penetrate. Anchoring the floats, as opposed to installing new pilings virtually
eliminates temporary noise impacts during installation, and it reduces in-water
structure.
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To mitigate for the proposed impacts, a number of improvements are proposed. In
total, over 121 creosote pilings are proposed for removal. Creosote leaches into
Lake Washington and contributes to impaired water quality. Their removal will
reduce the ongoing impact to water quality in the area. Additionally, the creosote
pilings that support the bulkhead, which are proposed to remain, will be cut below
the low water line and fitted with a steel sleeve. The outer pilings will be sealed
with a steel pipe sleeve, and the inner row of pilings will be sealed with steel sheet
pile and concrete fill.
The proposed project will reduce potential predator structure through the
removal of 121 piles. The proposed project will remove 225 square feet of
existing solid-decked overwater structures. The 3,853 square feet of new apron,
ramps and floats will be fully grated, and flotation materials will be minimized
to maximize light transmittal. Additionally, the proposed floats will be anchored
rather than supported through new piles.
The most effective strategy for minimizing or eliminating potential construction-
related impacts would be to restrict construction to periods when the presence of
bull trout, steelhead, and Chinook salmon is improbable. The combined fish-
protection prohibitions on in-water construction by NOAA Fisheries and USFWS
result in an allowable in-water construction window of July 16 through July 31
and November 16 through December 31. This window is adequate to minimize
the probability that bull trout, Chinook salmon, or steelhead would be in the
action area during construction. The precautionary conditions that have been
proposed would minimize the potential for the release of waste products or
construction debris to the lake. Additionally, during construction, any barge or
workboat used for construction would not be allowed to ground, and all
construction debris will be stockpiled on upland areas or on the construction
barge so that it can be properly disposed of on land in such a manner that it
cannot enter into the waterway or cause water quality degradation.
Through the removal of 121 piles, the project will significantly minimize in-water
structures that may attract predators to juvenile salmonids. The effects of new
overwater structures will be minimized through the use of grated decking and
through the use of helical anchors instead of new piles. The proposed
improvements, when considered with the proposed mitigation will result in no
net loss of ecological function, as demonstrated below in Table 2.
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Table 1. Impact Assessment
Structure Proposed for Removal
Proposed
New
Pilings (including dolphins) (number of pilings) 121 0*
Fully-grated Float (western) (square feet) 0 528
Fully-grated Float (eastern) (square feet) 0 2,013
Gully-grated apron along bulkhead (square feet) 0 1,312
Solid deck overwater structure (square feet) 225 0
*New piles will be driven if there are any missing bulkhead support piles.
Table 2. Functional Lift Analysis / No Net Loss Demonstration
Critical Area/
Shoreline Setback
Functions
Existing Conditions Proposed Conditions Functional Improvement?
Water
Quality
The shoreline area is essentially
entirely impervious and incapable of filtering stormwater
prior to entering the lake. Creosote pilings are leaching
into the lake.
Most derelict creosote pilings
are removed. Functional
pilings are sleeved or
otherwise sealed.
Yes; water quality will be slightly improved. While
the majority of leaching occurs early in the life of
the piling, some leaching of heavy metals and
contaminants will be avoided.
Hydrology
The shoreline area is essentially
entirely impervious and therefore lacks vegetative structure that
can slow stormwater velocities discharging into the lake from
nearby impervious areas.
Similar to existing
conditions.
Hydrologic function on
site will be maintained.
Habitat
The existing shoreline area is essentially entirely impervious
and lacks the native vegetation necessary to provide substantial
forage/cover opportunities. In-water habitat contains 100+
pilings providing bass habitat.
Invasive species
will be removed. A majority of
derelict pilings will be removed.
Habitat function will be
maintained. Piles that provide potential juvenile
salmon predator habitat will be removed.
Net
Condition
The shoreline area is heavily degraded with impervious surfaces at the shoreline edge and no native vegetation.
Derelict creosote pilings provide bass habitat and encourage
juvenile salmon predation.
Invasive species
are removed. 121 derelict
creosote pilings are removed.
Proposed fully grated floats
allow for light penetration.
Derelict piles will be removed, reducing
juvenile salmon predation. Invasive
species will be removed. Hydrologic and shoreline
habitat function will be maintained. Water quality
functions will be slightly improved. Overall, no
net loss of shoreline functions will occur.
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7 BEST AVAILABLE SCIENCE
In order to minimize and avoid potential impacts and provide adequate
mitigation, the proposed project and mitigation plan were designed using best
available science in accordance with RMC 4-8-120-19, and RMC 4-3-050-L-1-c. A
discussion of the potential affects to salmonids associated with the project
follows below.
7.1 Habitat
Graphs of trapping data indicate that juvenile Chinook salmon migrating from
the tributaries into Lake Washington exhibit two basic strategies: 1) direct
migration to the lake as fry without extended stream rearing; and 2) migration to
the lake as parr or smolts (average length 100 mm), following extended stream
rearing. Chinook fry begin entering Lake Washington around the first of the
year, peaking in February, while parr and smolts enter the lake from April
through July, peaking in late May (Tabor et al. 2006). Most naturally produced
Chinook salmon juveniles in Lake Washington originate in the Cedar River
(Celedonia et al. 2008). Past studies of juvenile Chinook salmon in Lake
Washington indicate that juvenile Chinook salmon were concentrated in the
south end of Lake Washington from February to May and the density of Chinook
salmon fry using lake shorelines in the spring decreases logarithmically with
increasing distance from the mouth of the Cedar River (Tabor et al. 2006).
The geographic proximity of the project site to the mouth of the Cedar River
suggests that the area may be significant to Chinook and other salmonids.
However, past studies in Lake Washington have found that juvenile Chinook
salmon prefer shallow water habitats with overhanging vegetation, with an
approximately 4.5:1 ratio of fish using overhanging vegetation to fish occurring
away from overhanging vegetation (Tabor et al. 2004, 2006). The project area
does not include shallow water habits or any significant overhanging vegetation.
During the period from mid-February to mid-April, Chinook salmon fry rear
along shorelines less than 1.6 feet in depth, and they are typically found within
30 feet from the OHWM (Tabor et al. 2006). As noted above, at high water,
depths adjacent to the bulkhead range from 8 to 17 feet; therefore, the project is
not expected to affect shallow water rearing habitats.
7.2 Overwater Cover
Juvenile Chinook salmon display avoidance behavior of piers. Surface water
observations found that upon approaching a pier, juvenile Chinook salmon will
move into deeper water and either pass under or swim around the pier (Tabor et
al. 2006). Similarly, in acoustic tracking studies, Chinook smolts avoided areas
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under overwater structures and changed course to move around such structures
(Celedonia et al. 2008). The change in light levels associated with piers and other
overwater structures may make it difficult for juvenile Chinook salmon to detect
predators (Tabor et al. 2006), and salmon predators like smallmouth bass are
often associated with pier piles (Celedonia et al. 2008). The proposed project will
reduce potential predator structure through the removal of 121 piles. The
proposed project will remove 225 square feet of existing solid-decked overwater
structures. The 3,853 square feet of new ramps and floats will be fully grated,
and flotation materials minimized to maximize light transmittal. Additionally,
the proposed floats will be anchored rather than supported through new piles.
Through the removal of 121 piles, the project will significantly minimize in-water
structures that may attract predators to juvenile salmonids. The effects of new
overwater structures will be minimized through the use of grated decking and
through the use of helical anchors instead of new piles.
7.3 Lighting
Juvenile salmonids on Lake Washington are attracted to bright artificial lighting
(Tabor et al. 2015), which can potentially make them more vulnerable to
predation. No lighting is currently proposed as part of the shoreline
improvements.
7.4 Water Quality (substrate disturbance and discharge of
waste products)
Pile and finger removal could produce temporary, localized sediment plumes
that would dissipate following cessation of activity. Turbidity is generally
considered an undesirable condition for salmonids, as exposure to potentially
contaminated or abrasive sediments suspended in the water column is thought
to result in lethal and sub-lethal effects (Newcombe and MacDonald 1991).
However, localized episodic turbidity events from an individual construction
activity would not represent a permanent sediment source and would not
produce conditions of chronic exposure necessary to produce a direct
detrimental effect on juvenile fishes (Newcombe and MacDonald 1991).
Considering that the turbidity produced by any construction activity would be
localized and temporary, the most probable impact on juvenile salmonids would
be a behavior modification (avoidance response), rather than injury or reduction
in growth potential. An avoidance response could expose juvenile salmonids to
increased predation or force them away from preferred rearing areas.
The most effective strategy for minimizing or eliminating potential construction-
related impacts would be to restrict construction to periods when the presence of
Chinook and coho salmon, steelhead, and bull trout is improbable. The
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combined fish-protection prohibitions on in-water construction are adequate to
minimize the probability that Chinook salmon, steelhead, or bull trout would be
in the action area during construction.
8 SUMMARY
The proposed project involves shoreline modifications to improve public
shoreline access through installation of boat moorage floats and to repair an
existing deteriorated bulkhead.
A total of 3,853 square feet of new, fully-grated overwater structure is proposed.
This number includes two new floats, one totaling 2,013 square feet and the other
totaling 528 square feet, and an over-water grated apron totaling 1,312 square
feet atop the bulkhead. To offset impacts associated with the proposed shoreline
modifications, multiple mitigation measures are proposed. Mitigation includes
removal of 107 derelict creosote piles, removal of 290 feet of horizontal
dimensional beams, removal of two dolphins (totaling 14 piles), removal of one
finger pier (85 square feet), removal of one ell end dock (140 square feet),
abandonment of a second finger pier (85 square feet), and abandonment of the
164-foot-long log boom.
The removal of these derelict piles and piers will result in an improvement in
water quality, while habitat and hydrological functions will be maintained.
Overall, no net loss of shoreline ecological functions will result from the
proposed project.
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steelhead from Washington, Idaho, Oregon, and California. National
Oceanographic and Atmospheric Administration Tech. Memo. NMFS-NWFSC-
27.
California Department of Transportation. 2007. Compendium of Pile Driving Sound
Data. Prepared by Illinworth & Rodkin, Petaluma, CA.
Celedonia, M.T., R.A. Tabor, S. Sanders, D.W. Lantz, and I. Grettenberger. 2008.
Movement and habitat use of Chinook salmon smolts and two predatory fishes
in Lake Washington and the Lake Washington Ship Canal: 2004-2005 Acoustic
Tracking Studies. U.S. Fish and Wildlife Service, Olympia, WA.
CG Engineering. 2016. Structural Observation Report- SECO Development Bulkhead.
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http://rp.rentonwa.gov/SilverlightPublic/Viewer.html?Viewer=COR-Maps
[Accessed May 27, 2016.
City of Seattle. 2008. Synthesis of Salmon Research and Monitoring (Investigation
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Utilities (SPU) and the U.S. Army Corps of Engineers (Corps), Seattle Division.
December 31, 2008.
DeVries, P. and 18 others. 2005. PIT tagging of juvenile salmon smolts in the Lake
Washington Basin: Fourth year (2003) pilot study results and synopsis of 2000-
2003 findings. Final Technical Report to the U. S. Army Corps of Engineers,
Seattle District, and Seattle Public Utilities.
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Threatened Species; Designation of Critical Habitat for Lower Columbia River
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_____. Volume 73, No. 200, 15 October 2008. Final Rule: Fisheries off West Coast States;
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The Watershed Company August 2016
19
_____. Volume 72, No. 91, 11 May 2007. Final Rule: Endangered and Threatened Species:
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_____. Volume 70, No. 185, 26 September 2005, Final rule. Endangered and Threatened
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confluentus).
_____. Volume 70, No. 170, 2 September 2005. Final rule: Endangered and Threatened
Species; Designation of critical habitat for 12 evolutionarily significant units of
west coast salmon and steelhead in Washington, Oregon, and Idaho -
Oncorhynchus tshawytscha.
_____. Volume 70, No. 123, 28 June 2005. Final rule: Endangered and Threatened
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4(d) protective regulations for threatened salmonid ESUs - Oncorhynchus
tshawytscha.
_____. Volume 69, No. 73, 15 April 2004, Notice of establishment of species of concern
list. Endangered and Threatened Species; Establishment of species of concern list,
addition of species to species of concern list, description of factors for identifying
species of concern, and revision of candidate species list under the Endangered
Species Act. Puget Sound/Strait of Georgia coho salmon (Oncorhynchus kisutch).
_____. Volume 64, No. 210, 1 November 1999. Final rule: Endangered and Threatened
Wildlife and Plants; Determination of threatened status for bull trout (Salvelinus
confluentus) in the coterminous United States.
_____. Volume 64, No. 147, 2 August 1999. Final rule: Endangered and Threatened
Wildlife and Plants; Listing of Nine Evolutionarily Significant Units of Chinook
Salmon, Chum Salmon, Sockeye Salmon and Steelhead.
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The Watershed Company August 2016
Appendix A
A PPENDIX A
Southport Shoreline Modifications
Site Plan
REVISED
REVISED
REVISED
REVISED
REVISED