HomeMy WebLinkAboutMiscWill Rogers-Wiley Post Memorial Seaplane Base
Biological Assessment
North facing view of the Renton Municipal Airport and Will Rogers-Wiley Post Memoria l Seaplane Base (Panoramio 2011 ).
April 2012
Prepared for:
U.S. Department of Homeland Security
FEMA Region X
130 228th Street SW
Bothell, WA 98021-9796
Contact: Science Kilner, Deputy Regional Environmental Officer
Prepared by:
City of Renton
Public Works Department
1055 South Grady Way
Renton, Washington 98055
Acronyms and Abbreviations
BA
BMP
CY
DMMU
DNR
DOE
DMMP
DPS
EFH
ESA
ESU
FEMA
GPS
HUG
LWD
MSA
NMFS
NTU
OHW
PCE
PSDDA
RSET
RM
Biological Assessment
best management practice
cubic yard
Dredged Materials Management Unit
Washington State Department of Natural Resources
Washington State Department of Ecology
Dredged Materials Management Program
distinct population segment
essential fish habitat
Endangered Species Act of 1973 (amended)
evolutionary significant unit
Federal Emergency Management Agency
global positioning system
Hydraulic Unit Code
large woody debris
Magnuson-Stevens Fishery Conservation and Management Act (amended 1996)
National Oceanic & Atmospheric Administration,
National Marine Fisheries Service
nephelometric turbidity units
ordinary high water
primary constituent element
Puget Sound Dredged Disposal Analysis Program
Regional Sediment Evaluation Team
river mile
Seaplane Will Rogers-Wiley Post Memorial Seaplane Base
Base
SEF Sediment Evaluation Framework
SPCC Spill Prevention Control and Countermeasures
TESC Temporary Erosion and Sediment Control
USFWS United States Fish and Wildlife Service
WDFW Washington Department of Fish and Wildlife
WRIA Water Resource Inventory Area
WSDOT Washington State Department of Transportation
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Executive Summary
This Biological Assessment has been prepared on behalf of the City of Renton. The
proposed project is located within the legal geographic area of Township 23 N, Range 5
W, Section 7 in the City of Renton, WA; Hydraulic Unit Code 171100120012. The Will
Rogers-Wiley Post Memorial Seaplane Base is located at the northern end of the City of
Renton Municipal Airport near the mouth of the Cedar River and southern terminus of
Lake Washington.
The purpose of the proposed project is to relieve the recent blockage of the Will Rogers-
.Wiley Post Memorial Seaplane Base by relocating approximately 16,000 cubic yards of
recently deposited silty sand substrate near the mouth of the Cedar River,. These
sediments were deposited during November 2006 and January 2009 flood events which
were declared federal disasters. The project proposes to deposit dredged substrates in
Elliot Bay, at a United States Army Corps of Engineers approved open water disposal site.
The removal of dredged sediment will return the lakebed habitat surrounding the seaplane
dock to a previously authorized elevation of 8.5 feet, (Vertical Datum: USAGE 1919)
restoring seaplane access to the Will Rogers-Wiley Post Memorial Seaplane Base.
Proposed project activities will require temporary removal of the existing dock decking,
replacement of at least one steel pipe pile, the dredging of substrate surrounding the
seaplane dock, and the deposit of dredged materials in Elliot Bay, at a United States Army
Corps of Engineers approved open water disposal site. Impacts of depositing dredged
materials in Elliot Bay are not assessed in this biological assessment as these actions are
covered under the Endangered Species Act (ESA) section 7(a)(2) Biological Opinion and
Magnuson-Stevens Fishery Conservation and Management Act Essential Fish Habitat
(EFH) Consultation, issued by the National Marine Fisheries Service, December 22, 2010,
and the Letter of Concurrence for the Puget Sound Dredge Disposal Analysis (PSDDA)
Program issued by the United States Fish and Wildlife Service, January 11, 2011 .
Project construction is proposed to start November 1 •1 of 2012 and anticipated to be
completed within 150 days. All in-water work will be done within the United States Army
' Debris removal operations are statutorily excluded from NEPA by section 316 of the Robert T. Stafford
Disaster Relief and Emergency Assistance Act (Stafford Act), as amended, 42 U.S.C. 5159.
Corps of Engineers approved in-water work window (July 16'"-July 31'' and November 16'"
to December 31 '').
The United States Fish and Wildlife Service and the National Oceanic and Atmospheric
Administration-National Marine Fisheries Service indicated listed species may occur in
the project area. Potential impacts to listed species may result from possible increases in
sedimentation/turbidity during the removal/placement of dredged materials and vibratory
pile extraction/installation. Elevated sound pressure levels are also anticipated during pile
installation/extraction.
Conservation measures such as erosion control best management practices, a Spill
Prevention Control and Countermeasures Plan, and a designated in-water work window
(July 16-July 31 and November 16th to December 31st) have been incorporated into the
project in order to minimize and/or avoid project impacts. Vibratory pile
extraction/installation will occur for no more than four hours over a period of no more than
two days.
The following table summarizes effect determinations for all listed species and designated
critical habitats within the action area:
Species Effect Determination
Coastal-Puget Sound DPS of Bull Trout May Affect, Not Likely to Adversely Affect
(Salvelinus confluentus)
Bull Trout Critical Habitat May Affect, Not Likely to Adversely Affect
Puget Sound ESU of Chinook Salmon May Affect, Not Likely to Adversely Affect
(Oncorhynchus tshawytscha)
Chinook Salmon Critical Habitat May Affect, Not Likely to Adversely Affect
Puget Sound DPS of Steelhead Trout May Affect, Not Likely to Adversely Affect
(Oncorhynchus mykiss)
Table of Contents
Chapter 1 Project Overview ............................................................................................ 1-1
1.1 Federal Nexus ................................................................................................... 1-1
1.2 Project Description . .... ..... ....... ....... ......... .... .. .......................................... 1-2
1.2.1 Existing Condition .............................................................................................. 1-2
1.2.2 Proposed Condition .......................................................................................... 1-2
1.3 Project Area and Setting .................................................................................... 1-3
Chapter 2 Federally Listed Species and Designated Critical Habitat ............................... 2-1
2.1 Species List ....................................................................................................... 2-1
2.2 Occurrence of Species in Action Area ............................................................... 2-2
2.2.1 Coastal/Puget Sound DPS of Bull Trout ........................................................... 2-2
2.2.2 Puget Sound ESU of Chinook Salmon ............................................................. 2-3
2.2.3 Puget Sound DPS of Steelhead Trout .............................................................. 2-4
2.3 Designated Critical Habitat ................................................................................ 2-5
2.3.1 Critical Habitat for Bull Trout ............................................................................. 2-5
2.3.2 Critical Habitat for Chinook Salmon .................................................................. 2-6
Chapter 3 Environmental Baseline ................................................................................... 3-1
Terrestrial Resources/ Habitat. .................................................................................... 3-1
3.1.1 Topography ...................................................................................................... 3-1
3.1.2 Land Use ........................................................................................................... 3-2
3.1.3 Vegetation ......................................................................................................... 3-2
3.1.4 Noise Environment. ........................................................................................... 3-2
3.2 Water Resources ............................................................................................... 3-2
3.2.1 Hydrology .......................................................................................................... 3-2
3.2.2 Substrate ........................................................................................................... 3-3
3.2.3 Wetlands ........................................................................................................... 3-4
3.2.4 USFWS Combined Pathways and Indicators Matrix ......................................... 3-4
Chapter 4 Project Details ................................................................................................. 4-1
4.1 Construction ...................................................................................................... 4-1
4.1.1 Project Timeline and Sequencing ..................................................................... 4-1
4.1.2 Site Preparation ................................................................................................ 4-2
4.1.3 Construction Access and Staging ................................................................... 4-2
4.1.4 In-Water Work ................................................................................................... 4-3
4.1.5 Potential Impacts on Water Quality ................................................................. 4-17
4.1.6 Post-Project Site Restoration .......................................................................... 4-19
4.2 Conservation Measures ................................................................................... 4-19
4.2.1 Site and Equipment Preparation ..................................................................... 4-19
4.2.2 Construction Methods and Timing .................................................................... 4-20
4.3 Operations ....................................................................................................... 4-20
4.4 Maintenance .................................................................................................... 4-20
Chapter 5 Project Action Area ......................................................................................... 5-1
5.1 Limits of an Action Area ..................................................................................... 5-1
5.1.1 Zone of Terrestrial Impacts ............................................................................... 5-1
5.1.2 Zone of Aquatic Impacts ................................................................................... 5-2
5.2 Defining an Action Area ..................................................................................... 5-3
Chapter 6 Effects Analysis ............................................................................................... 6-1
6.1 Direct Effects ..................................................................................................... 6-1
6.1.1 Underwater Vibrations ...................................................................................... 6-1
6.1.2 Water Quality .................................................................................................... 6-2
6.1.3 Substrate Redistribution .................................................................................... 6-4
6.1.4 Shading ............................................................................................................. 6-5
6.1.5 Organic Inputs .................................................................................................. 6-5
6.1.6 Wetlands ........................................................................................................... 6-5
6.2 Indirect Effects ................................................................................................... 6-5
6.2.1 Predator-Prey Relationships ............................................................................. 6-5
6.3 Interrelated and Interdependent Actions ........................................................... 6-5
Chapter 7 Effect Determinations ...................................................................................... 7-1
7.1 Effect Determinations for Listed Species ........................................................... 7-1
7.1.1 Coastal/Puget Sound DPS of Bull Trout .......................................................... 7-1
7.1.2 Puget Sound ESU of Chinook Salmon ............................................................. 7-2
7.1.3 Puget Sound DPS of Steelhead Trout .............................................................. 7-3
7.2 Analysis of Effects to Critical Habitat Primary Constituent Elements ............... 7-7
7.2.1 Designated Critical Habitat for the Coastal/Puget Sound DPS of Bull Trout .... 7-7
7.2.2 Designated Critical Habitat for the Puget Sound ESU of Chinook Salmon ..... 7-10
Chapter 8 References ...................................................................................................... 8-1
Appendices
Appendix A: Essential Fish Habitat ................................................................... A-1
Appendix B: Detailed Species lnformation ............................................................ 9-1
Appendix C: Soil Characterization ........................................................................ C-1
Appendix D: Pathways and Indicators Matrix Parameters ........................................ .D-1
Appendix E: Noise Analysis ............................................................................... E-1
List of Figures
Figure 1: Vicinity Map ...................................................................................................... 1-5
Figure 2: Project Area Map ............................................................................................. 1-7
Figure 3: Area to be Dredged ...................................................................................... 4-11
Figure 4: Cross Sections of the Area to be Dredged .................................................... .4-13
Figure 5: Action Area ....................................................................................................... 5-5
List of Tables
Table 1: Listed species and designated critical habitat listed as being potentially present
in the project action area ................................................................................... 2-1
Table 2: Pathway and indicator matrix for Lake Washington within the aquatic action area
......................................................................................................................................... 3-4
Table 3: Summary of listed species activities and construction periods ........................ 7-5
List of Photos
Photo 1: Accumulated sediments within Lake Washington near the Seaplane Base ..... 3-1
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Chapter 1 Project Overview
1.1 Federal Nexus
This Biological Assessment (BA) has been developed to address the proposed action in
compliance with Section 7(c) of the Endangered Species Act (ESA) of 1973, as amended.
Section 7 of the ESA requires that, through consultation with the US Fish and Wildlife
Service (USFWS) and/or the National Oceanic and Atmospheric Administration-National
Marine Fisheries Service (NMFS), federal actions do not jeopardize the continued
existence of any threatened, endangered, or proposed species or result in the destruction
or adverse modification of critical habitat (ESA 2002).
Section 305(b)(4) of the Magnuson-Stevens Fishery Conservation and Management Act
(MSA), requires that each Federal agency shall consult on any action authorized, funded,
or undertaken, or proposed to be authorized, funded, or undertaken, by this agency that
may adversely affect any essential fish habitat (EFH) identified in the MSA. Appendix A of
this BA addresses EFH as protected under the MSA as amended 1996 and regulated by
the NMFS (NMFS 1996).
The project is using funding from the Federal Emergency Management Agency (FEMA)
though it will be managed by the City of Renton.
1.2 Project Description
1.2.1 Existing Condition
The Seaplane Base consists of a taxi channel and basin, two floating docks for
passenger boarding and offloading and a launch/retrieval ramp. The entrance taxi
channel for float plane navigation is approximately 150 feet in width. The existing
seaplane dock consists of about 3,620 square feet (sq ft) of floating docks. There are two
existing docks in place, one with an L-shaped configuration, extending approximately 40 ft
parallel to shore and approximately 70 ft perpendicular to shore. The second dock
extends approximately 190 ft parallel to the shoreline.
The existing shoreline along the Renton Municipal Airport is lined with sheetpile wall
adjacent to the seaplane dock. From the seaplane ramp to the mouth of the Cedar River
the shoreline is armored with riprap.
Currently the lakebed surrounding the seaplane base is overloaded with sediments
deposited during the November 2006 and January 2009 flood events which were declared
federal disasters. It is estimated the portion of the current lakebed to be dredged ranges
between 10 and 18 feet above mean sea level (Vertical Datum: USAGE 1919). In order to
ensure that existing seaplane operations can be maintained safely, maintenance dredging
must be performed in this area.
1.2.2 Proposed Condition
The project proposes to return the lakebed habitat surrounding the aforementioned docks
to the previously authorized elevation of 8.5 feet above mean sea level (Vertical Datum:
USAGE 1919).
1.3 Project Area and Setting
The Will Rogers-Wiley Post Memorial Seaplane Base (Seaplane Base) is located at the
north end of the Renton Municipal Airport, west of the Cedar River, on the southern shore
of Lake Washington in the City of Renton, King County, WA.
The project area is located within the legal geographic area of Township 23 North, Range
5 East, Section 7, Willamette Meridian, with a latitude of 47°30'02.07" north and a
longitude of 122°13'04.78" west (Water Resource Inventory Area (WRIA) 08: Lake
Washington, Hydraulic Unit Code (HUC) 171100120106. Refer to Figures 1 and 2.
The land portion of the project area is relatively flat at an elevation of approximately 25
feet (Vertical Datum: USACE 1919). Bathymetry within the Lake Washington portion of
the project area is gently rolling with elevations ranging from 8 ft to 23 ft (Vertical Datum:
USACE 1919).
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Proposed Dredging to 8 feet
~ Limits of Side Slope
~ Barge Loading Area
-Cedar River
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75 150
Figure 2: Project Area
Seaplane Base Improvements Project
City of Renton
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Chapter 2 Federally Listed Species and
Designated Critical Habitat
2.1 Species List
Both the USFWS and NMFS listed species that are potentially present within King County
and/or Lake Washington are summarized in Table 1. The most current version of the
USFWS list, revised March 15, 2012, is referenced for this assessment (USFWS 2012).
The NMFS list was last updated August 11, 2011 (NMFS 2011 a).
Table 1: Listed species and designated critical habitat listed as being potentially present
in the project action area
Common Name Scientific Name Federal Status
Bull Trout Sa/velinus confluentus Threatened
/Coastal/Puaet Sound DPS\
Bull Trout Critical Habitat Designated
/Coastal/Puaet Sound DPS\
Canada Lvnx Lvnx canadensis Threatened
Chinook Salmon Oncorhynchus Threatened
<Puaet Sound ESU\ tshawvtscha
Chinook Salmon Critical Habitat Designated
IPuaet Sound ESUl
Golden Paintbrush Castilleia /evisecta Threatened
Grav Wolf Canis /uois Endanaered
Grizzlv Bear Ursus arctos Threatened
Marbled Murrelet Brachyramphus Threatened
marmoratus
Marbled Murrelet Critical Habitat Desianated
Northern Snotted Owl Strix occidentalis caurina Threatened
Northern Spotted Owl Critical Designated
Habitat
Steel head Oncorhynchus mykiss Threatened
IPuaet Sound DPSl
There is no suitable habitat or documented occurrences of Canada lynx, golden
paintbrush, gray wolves, grizzly bears, marbled murrelets, or northern spotted owls within
the action area nor is any critical habitat for marbled murrelets or northern spotted owls
designated within the action area; therefore, this project will not affect these species and
they will not be discussed further in this report. Critical habitat has been designated for
Coastal/Puget Sound bull trout and Puget Sound Chinook salmon within the aquatic
portion of the action area.
Note that this BA does not evaluate potential impacts to Dolly Varden, which is proposed
based on Similarity of Appearance to a threatened taxon (bull trout). Under the Similarity
of Appearance provisions of the ESA, Section 4(e) authorizes a species to be treated as if
it were endangered or threatened if it closely resembles a listed species and law
enforcement personnel would have substantial difficulty telling the two species apart.
Although species listed under the Similarity of Appearance provisions receive some of the
protections of the ESA, consultation requirements under Section 7 do not apply.
The Washington State Department of Natural Resources (DNR) Natural Heritage
Information System was reviewed for federally listed plant species within the area,
including the golden paintbrush; none are present (DNR 2010).
2.2 Occurrence of Species in Action Area
2.2.1 Coastal/Puget Sound DPS of Bull Trout
The Coastal/Puget Sound distinct population segment (DPS) of bull trout was federally
listed as a threatened species on November 1, 1999 (USFWS 1999b). The species list
obtained from the USFWS indicates that bull trout are present in King County (USFWS
2012). There is no known regular occurrence of bull trout within Lake Washington
(WDFW 2011a).
A population of more than 3,000 adfluvial' bull trout is known to occur in the Chester
Morse Reservoir, approximately 39 miles from the project in the Cedar River Reservoir.
1 Adfluvial refers to fish spend most of their lives in lakes and migrate into streams to spawn.
Over the last thirty years small numbers (one to several) of individual amphidromous' bull
trout have been observed in the Hiram M. Chittenden Locks and/or Lake Washington
(Kerwin 2001); however, it is believed these fish likely originated from other basins and
were simply foraging in Lake Washington, or they are isolated individuals that have moved
downstream from the Chester Morse population. While no other viable population of bull
trout is known to occur in the Cedar River/Lake Washington Basin the USFWS has
classified Lake Washington as bull trout migration and overwintering habitat (City of
Seattle 2011 ).
As no known viable population of bull trout is known to inhabit Lake Washington it is
unlikely they would be present within the within the aquatic action area at the time of in-
water work, or any time of the year. However, as prey species exist within the aquatic
portion of the action area, bull trout could potentially be foraging in the area.
2.2.2 Puget Sound ESU of Chinook Salmon
The Puget Sound evolutionary significant unit (ESU) of Chinook salmon was federally
listed as a threatened species listed on March 24, 1999 (USFWS 1999a). The species list
obtained from NMFS indicates that Chinook salmon may be present within the aquatic
portion of the action area (NMFS 2011 a). Adult Chinook salmon are known to migrate
though Lake Washington on their way to spawn in the Cedar and Sammamish River
(WDFW 2011 a). Juveniles are known to both rear within and outmigrate through Lake
Washington on their way to the ocean (Tabor and Piaskowski 2002).
Adult Chinook first arrive at the Hiram M. Chittenden (Ballard) locks, on their way to
spawning grounds (approximately 1 mile from the project area in the Cedar River), in mid-
June, peak in mid-to-late August, and are generally through the locks by early November
(Kerwin 2001 ).
Shortly after emerging from their redds, many juvenile chi nook salmon fry migrate to Lake
Washington in February and March where they may inhabit the lake environment for 4 to
5 months (Tabor and Piaskowski 2002). Chinook fry tend to concentrate in the littoral
' Amphidromous refers to the migratory behavior of fishes which move from fresh water to the sea and vice versa, not for breeding
purposes but occurring regularly at some stage of the life cycle (such as feeding or overwintering!.
zone at the south end of Lake Washington until they grow large enough to move offshore
(Tabor et a/. 2004, Tabor et a/. 2006). Therefore, the lakeshore area near the Cedar River
mouth appears to be an important nursery area for juvenile Chinook. Fry appear to
migrate slowly along the shorelines, rearing in very shallow water (<3 ft) on unvegetated,
sandy-gravel beach portions of the shoreline (Tabor and Piaskowski 2002, McCoy et al.
2003).
At the time of in-water work (November 161h to December 31'1) it is not anticipated that
Chinook salmon will be present within the aquatic portion of the action area as adults will
have migrated to freshwater tributaries to spawn and juveniles will have already
outmigrated to the ocean.
There are no records of spring or summer Chinook occurring within Lake Washington;
therefore, these races will no longer be discussed in this biological assessment (WDFW
2011 a).
2.2.3 Puget Sound DPS of Steelhead Trout
The Puget Sound DPS of Steelhead Trout was federally listed as a threatened species on
May 11, 2007 (NMFS 2007). The species list obtained from NMFS indicates that
steelhead trout may be present within the aquatic portion of the action area (NMFS
2011 a). Winter steelhead trout are known to migrate through Lake Washington (WDFW
2011 a).
Historically, adult steelhead trout entered Lake Washington through the Hiram M.
Chittenden Locks between December and May (WDFW 2011 b). These steelhead make
their way to the Cedar River, spawning primarily in the mainstem (approximately 1.8 miles
from the project area) from March through early June (WDFW 2011a, King County 2008).
Juvenile steelhead trout are known to rear in the Cedar River and its tributaries
downstream of the Landsberg Diversion Dam located at river mile (RM) 21.6 (City of
Seattle 2011 ). However, as fish passage structures were incorporated into the dam in
2003, steelhead distribution may continue upstream to the Masonry Dam (RM 37)(City of
Seattle 2011 ). Juvenile steel head trout are known to rear in the Cedar River for
approximately 2 years, until smolts. After this time, they are known to migrate
downstream to Lake Washington. Some of the juvenile steelhead migrating from the
Cedar River are likely to use the project site or adjacent areas within the aquatic portion of
the action area as a migratory corridor. While steelhead are known to outmigrate year
round, it is likely peak outmigration will occur during period of higher flows and lower water
temperatures. Adult steelhead returning to the Cedar River are likely to stage in deeper
waters within the aquatic portion of the action area.
Both juvenile and adult steel head may be present in the aquatic portion of the action area
during the time of proposed in-water work (November 161h-December 31 51).
There are no records of summer steelhead occurring within Lake Washington; therefore,
this race will no longer be discussed in this biological assessment (Kerwin 2001, WDFW
2011a).
2.3 Designated Critical Habitat
Critical habitat is a specific geographic area(s) that contains features essential for the
conservation of a threatened or endangered species and that may require special
management and protection. Critical habitat may include an area that is not currently
occupied by the species but that will be needed for its recovery (USFWS 2005b).
2.3.1 Critical Habitat for Bull Trout
High quality bull trout habitat is typically characterized by cold temperatures; migratory
corridors with minimal physical, biological, or water quality impediments; an abundant food
base; and permanent water of sufficient quantity and quality such that normal growth and
survival are not inhibited (Shellberg 2002, USFWS 2005a).
Critical habitat for the Coastal/Puget Sound DPS of bull trout has been designated in the
aquatic portion of the action area (USFWS 2010).
2.3.2 Critical Habitat for Chinook Salmon
Chinook prefer deep, cool water with larger gravel and a good water flow for eggs to
survive. Early stages are susceptible to low oxygen conditions, reductions in river flow,
high water temperatures, and loss of stream cover (Wydoski and Whitney 2003).
Critical habitat for the Puget Sound ESU of Chinook salmon has been designated in the
aquatic action area (NMFS 2005).
Chapter 3 Environmental Baseline
Terrestrial Resources I Habitat
3.1.1 Topography
The general topography in the project vicinity was heavily influenced by the Vashon Ice
Sheet, which occupied the area and retreated to the north approximately 13,000 years
ago. Lake Washington occupies a glacially excavated, elongate trough bounded by north-
south trending elongate ridges and drift uplands.
The project area is located along the southern shoreline of Lake Washington within the
Puget Sound Basin. This location became terrestrial land with the lowering of Lake
Washington by about 9 feet in 1916. The land portion of the project area is relatively flat
at an elevation of approximately 25 feet (Vertical Datum: USACE 1919). Bathymetry
within the Lake Washington portion of the project area is gently rolling with elevations
ranging from 8 feet to 23 ft (Vertical Datum: USACE 1919). Refer to Photo 1.
Photo 1: Accumulated sediments within Lake Washington near the Seaplane Base
3.1.2 Land Use
Renton Airport occupies land on the western side of the river and the Boeing Renton
Facility occupies the land on the eastern side. Narrow bands of riparian vegetation line the
channelized lower mile of the Cedar River. Land use in the project vicinity is industrial
and urban center (City of Renton 2009).
3.1.3 Vegetation
The Seaplane Base Improvements Project is located within the Tsuga heterophyl/a major
vegetation area (Franklin and Dyrness 1973, Jackson and Kimerling 1993). Vegetation
surrounding the project area consists of various ornamental trees, shrubs and mowed
lawns.
3.1.4 Noise Environment
The project is located on a Seaplane Base adjacent to Renton Municipal Airport;
therefore, the noise environment within the project area is characterized by both airplane
and vehicular traffic noise with an ambient level of 55 dBARMs(City of Renton 2007).
3.2 Water Resources
3.2.1 Hydrology
The project area is located along the southern shoreline of Lake Washington, near the
mouth of the Cedar River, within the main basin of Puget Sound (NMFS 2011 b). During
the summer the lake level reaches approximately 22 feet in elevation, or ordinary high
water (OHW)( Vertical Datum: USACE 1919). However, during the winter the lake level is
generally only 20 feet in elevation ((Vertical Datum: USACE 1919).
Within the aquatic portion of the action area, Lake Washington is a Category 2' water for
fecal coliform and a Category 1' water for total phosphorus. At its mouth, the Cedar River
• Category 2 waters of concern are waters where there is some evidence of a water quality problem, but not enough to require
production of a water quality improvement project (also known as a total maximum daily load (TMDL)) at this time.
s Category 1 waters meet the tested standards for clean waters:
is a Category 2 water for pH and a Category 5" water for fecal coliform, temperature and
dissolved oxygen (DOE 2009).
Turbidity within the project area ranges from 1-4 nephelometric turbidity units (NTU)
during the summer to 50-200 NTU during winter floods (King County 2010, NRA 2010).
During the time of proposed in-water work it is anticipated that background turbidity levels
will be between approximately 2 NTU and 150 NTU as the project area receives high
sediment loads of silty sand from the Cedar River.
The annual average precipitation in the City of Renton is 39.59 inches (City of Renton
2010).
3.2.2 Substrate
Lake Washington is not listed on the Washington State Department of Ecology's (DOE)
Water Quality Assessment for Washington as having any sediment in the area exceeding
the Sediment Management Standards CSL bioassay criterion (DOE 2009).
Within the aquatic portion of the action area, the area to be dredged was divided into two
dredged materials management units (DMMU); one west and one east of the dock.
Sediment samples were taken within each unit. Substrate within the western DMMU was
found to consist of approximately 80 percent sand and 20 percent silt while substrate
within the eastern DMMU consists of approximately 90 percent sand, five percent gravel
and five percent silt (Appendix C). The sediment to be dredged from the Seaplane Base
site does not have contaminants exceeding sediment management standards set by the
Regional Sediment Evaluation Team (RSET) as documented in the Northwest Regional
Sediment Evaluation Framework (SEF)(USACE 2011 ). Refer to Appendix C for a
comparison of on-site samples to these criteria.
• Category 5 waters of concern are polluted waters that require a TMDL. Placement in this category means that Ecology has data
showing that the water quality standards have been violated for one or more pollutants, and there is no TMDL or pollution control plan.
TMDLs are required for the water bodies in this category.
'This was approximated based on averaging multiple on-site readings taken in the early winter.
; ,-..
3.2.3 Wetlands
The National Wetlands Inventory shows no wetlands within a one-mile radius of the
project area (USFWS 2011 ).
3.2.4 USFWS Combined Pathways and Indicators Matrix
The USFWS and NMFS developed a Pathways and Indicators Matrix (WSDOT 2010b)
which is further discussed in Appendix D. A summary of the affected baseline aquatic
conditions of Lake Washington and anticipated changes due to the proposed project is
shown below.
Table 2: Pathway and indicator matrix for Lake Washington within the aquatic action area
ENVIRONMENTAL BASELINE EFFECTS OF THE ACTIONS
PATHWAYS:
INDICATORS Properly At
Functioning Risk
Not P~operly Restore I Maintain Degrade
Functioning Enhance
WatEi'r.'Clu"'if ;··: < , .. ,:. , , · "'' , , ... ,, "· ""' . ,. . . . . . . .~ JY. . ·.· ' .. , ,,. . '{; • , ,~:'f~r, · ;, .. ;:r~ ; ·:,;;:{t< · ·•·,i;};
Temperature X X
SedimenU Turbidity X X X
(long-term) (short-term)
Chemical Contaminants/ X X X
Nutrients (long-term) (short-term)
f18tiffiit/1\'.0CeSS'J~~~~~f f· .:_~~--r r:~~: ~k:£-fl/f,i ::>;'..:~::1.--~N ~{<;·.;,-·j1:t': -<~·; ;.\~:--f,:y! ~;~:.: {-:.,, :'.\'.~ --;_~··y+ ._.-·J:t.' t;:.;T:>::15~:,r::·"t:~r _ »Vt~1*f ~J?·:l~>M;\'{ · --.: ·
Physical Barriers X
Ha1:iltat,1-;1"'mii'fltsfl/:r1'~t:t::T' :, ·1,,0·<: ·· , • '·"'
Substrate
Embeddedness in
Rearino Areas
Large Woody Debris X
Road Density and
Location
Disturbance Regime
Riparian Reserves
X
X
,,
X X
X
X
X
X X
X X
Chapter 4 Project Details
4.1 Construction
Construction activities would consist of 1) removing a portion of the existing dock, 2)
dredging of substrate around the seaplane dock and 3) depositing dredged material in
Elliot Bay, at an United States Army Corps of Engineers (USAGE) approved open water
disposal site, and 4) reconstructing the dock. In-water work will be required for all of the
aforementioned activities. All in-water work will be done within the USAGE approved in-
water work window (July 15th.July 31 51 and November 15th to December 31'1).
4.1.1 Project Timeline and Sequencing
The anticipated general order of work on this project is as follows however, some stages
may be completed simultaneously. Each stage has been deconstructed into its primary
components in the next sections.
Site Preparation
1. Mobilization
2. Remove dock
Dredge Basin
1. Dredge substrate and load barges
Deposit Dredged Material
1. Transport and disposal at Elliot Bay Open Water Disposal Site
Reconstruct Dock
1. Replace Broken Pilings
2. Install Decking
Project construction is proposed to start November 1st of 2012 and anticipated to be
completed by December of 2011. In-water work will only occur within the USAGE
approved in-water work window (July 15t"-July 31st and November 16'" to December 31st)_
Construction activities will require the use of dump trucks, bulldozers, front loaders,
excavators, a crane, and a vibratory pile extractor.
4.1.2 Site Preparation
Mobilization
A key task in mobilization is for the contractor to submit a debris containment plan prior to
the start of construction. The plan will describe how the contractor will contain debris and
prevent it from entering Lake Washington.
Temporary Erosion and Sediment Control
Disturbance of vegetation is not anticipated as all work is anticipated to be performed from
barges, from the existing dock, or from the airport tarmac. While no erosion is anticipated,
project activities do have the ability to adversely affect surface waters due to dredging
operations. Both a Temporary Erosion and Sediment Control (TESC) Plan and a Spill
Prevention Control and Countermeasures (SPCC) Plan must be prepared by the
contractor as per the Washington Department of Transportation's (WSDOT) standards as
outlined in the Highway Runoff Manual (WSDOT 2011) and provided to the City of Renton
for approval prior to the initiation of construction. Impacts are not expected to exceed the
water quality standard set forth in the 401 permit from the DOE.
Survey for Dredging
Dredging limits will be surveyed prior to the start of construction and a global positioning
system (GPS), on-board the dredge, will be used to ensure dredging occurs within the
proposed limits.
4.1.3 Construction Access and Staging
Access to the worksite will occur via the Renton Municipal Airport and by barge. Both the
barge and airport parking lot will be used for staging and stockpiling. All debris will be
contained and disposed of off-site at an approved disposal site.
4.1.4 In-Water Work
In-water work will be required for the removal and installation of at least one 12-inch steel
pipe pile, the dredging of substrate surrounding the seaplane dock, and the deposition
dredged material in Elliot Bay, at an USAGE approved open water disposal site. Debris
removal operations (i.e. dredging) are statutorily excluded from NEPA by section 316 of
the Robert T. Stafford Disaster Relief and Emergency Assistance Act (Stafford Act), as
amended, 42 U.S.C. 5159.
The proposed project actions have been designed in order to minimize possible increases
in turbidity, as such it is anticipated that any increases will be de minimis; within the DOE
Section 401 water quality standards. To ensure compliance with these standards,
qualified personnel' will be on-site monitoring' for turbidity during all in-water work. If at
any time turbidity levels exceed those permitted'°, project actions will cease until a time
that turbidity decreases to near background levels.
Dredging activities will occur for a period of 160 hours over a period of no more than 20
days during the in-water work window (July 161" -July 31'1 and November 16'" to
December 31'1).
4.1.4.1 Dredge Basin
The project has been approved by the Puget Sound Dredged Disposal Analysis Program
(PSDDA) to dredge up to approximately 16,000 cubic yards (CY) of recently deposited
silty sand substrate from below OHW within Lake Washington, returning the lakebed
habitat surrounding the seaplane base to an elevation of 8.5 feet (Vertical Datum:
• Qualified personnel includes either a technician, biologist or a certified erosion control and sediment lead (CECSL) who has been
trained and is familiar with proper sampling methods, compliance standards and the operation/calibration of the turbidtty meter which
will be used to monitor for compliance.
• The following water quality monitonng procedures are provided as a preliminary description and may be modified at the request of a
regulatory agency. Turbidity monitoring will occur 100 and 150 feet north, east and/or west from the activity potentially resulting in
increased turbidity levels (activtty of concern). Measurements at the 100-foot distance would allow for modification of operations to
avoid exceedance at the compliance boundary of 150 feet. A water quality monitoring plan will be developed by the applicant and
submitted to the regulatory agencies prior to the start of construction for review. The water quality monitonng plan will provide detail
on the location of sampling of background and monitoring stations, frequency of testing, equipment to be utilized and procedures for
reporting and additional best management practices which may be needed to ensure compliance with the water quality certification
requirements. The water quality monitoring plan will be developed in accordance with the requirements outlined in the Water Quality
Certification.
'° Water quality standards for turbidity in 'Salmonid Spawning, Rearing, and Migration" waters are as follows: turbidity shall not exceed
5 NTU over background conditions when the background is 50 NT u or less, or a 10 percent increase in turbidity when the background
turbidity is more than 50 NTU.
USAGE 1919). Sediment will be dredged from a 48,000 square foot (sq ft) area to reach
the 8.5 foot permitted depth adjacent to the seaplane base (Figures 2, 3 and 4).
Approximately 2 to 9 feet of sediment will be dredged from this area. An additional area of
approximately 28,000 square feet will be dredged in order to create 4:1 side slopes.
Dredging work will be conducted utilize mechanical methods utilizing clamshell buckets.
The clamshell dredge will be mounted on a spud barge. The proposed clamshell dredge
will use the appropriate bucket size practical for site conditions to minimize the number of
dredge bites in order to minimize turbidity. The clamshell will only take one bite per
dredge cycle in order to minimize possible sediment loss during the opening/closing of the
bucket within the water column. Dredge cycles will be performed at a rate that will reduce
the potential of waters washing dredged sediment from the bucket as it rises through the
water column. At no time will any sediment be stockpiled within the water.
After extraction, dredge materials will be stockpiled and transported on the barge; at no
time will barges be overfilled. The barge will have a draft of approximately 8-10 feet and
will be held in place using two spuds. Within the northern portion of the dredging area and
where depths allow, dredged material will be placed directly onto bottom dump barges. In
areas around the docks which will not allow access, dredged material will be placed onto
smaller hopper barges. Once filled, hopper barges will be moved to deeper water for
moving materials to the larger bottom dump barges. Hopper barges will be fitted with side
boards for containment and scuppers for water drainage. Scuppers will be fitted with silt
fence, straw bales, and other materials to filter and contain materials during dewatering.
Barge dewatering will occur within the dredged area prior to loading bottom dump barge.
If determined to be needed, a floating debris boom will be placed around the perimeter of
the dredging equipment to aid in containment of floating debris and suspended sediments.
Once loading is complete, the bottom dump barge will be transported to and from the
Elliot Bay USAGE approved open water disposal site.
! •
§,
l
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NOTES:
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1. SPECIAL DREDGE PROCEDURES APPLY TO WORK ADJACENT TO EXISTING SlRUCTURES
ANO UTILITIES FOR THE PROTECTION OF THOSE F AGILITIES.
~~-~,,5· \\weoR-----,
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FLOATING CONCRETE-DOCK ~ rt~-~~::: ....... .-"---. ---~~~~:::.:::::::-..::::------\
CONCRETE BULKHEAD
....J
EXISTING CONCRETE OUTFALL
CITY OF RENTON PROPERTY LINE
APPROX. LOCATION OF 12" SO
OUTFALL NOTCH FILL BELOW PIPE
DREDGING SITE PLAN
0 30 60
--~
RAMP:;-). ~---'2.5---
TOP OF DREDGE SLOPE, TYP.
TOE OF DREDGE SLOPE, TYP.
I
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--------------------------------------------------
WATER LEVEL TABLE (LAKE WA)
ORDINARY HIGH WATER
ORDINARY LOW WATER
22.0'
20.0·
I I
2. ESTIMATED DREDGE VOLUME: 16,000 CY INCLUDING 1-FT OVEROREOGE ALLOWANCE.
SCALE IN FEET
. = 1-·· :. ,.,,, -'".!!l!!El1. ~y CITY OF RENTON ,t".;:;.
:, DESIGNED BY JD ... ,., "''""' I coAsT & HARBOR ENGINEERING 0~o.c, SEAPLANE BASE MAINTENANCE
ENTERED BY TM VERIFY SCALE 110 MAIN STREET, SUITE 103 ~ ~ CHECKED BY SP "' "'""' '"' • ""' ""' <> ''"'" EDMONDS, WA 98020 • "' + J DREDGING PROJECT SHECT o CIRA~GS ANCI HALF INCH ON PH 425-778-2542 ~-{:::,. 2
-; PROJECT ENGINEER JO 0383 1h17 CIRA\\UtGS, IF MOT, AMJST FAX 425-778-6883 ~r__-tg :V· OF
" PROJECT MANAGER SP 3/28/12 CONCEPTUAL FOR REVIEW TM ''""""'" """'""""''": ,y_'t':; CONCEPTUAL SITE PLAN 3 I
[;! DA TE REVISION BY Cl 1 sH££TS
EXISTING BULKHEAD
0+25 0+50
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0 0
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f2
NOTES
T.D. DREDGE SLOPE
EXISTING FLOATING
DDCK AND PILE
EXISTING GROUND SURFACE
8.0. DREDGE CUT EL +9.5'
AREA TO BE DREDGED
0+75 1+00 1+25 1+50 1+75 2+00 2+25 2+50 2+75
DISTANCE, FT
SECTION
DREDGE CUT EL +9.5'
EXISTING GROUND SURFACE
AREA TO BE DREDGED
EXISTING FLOATING DOCK AND PILE
SECTION
0 30 60
w
0.
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1. ESTIMATED DREDGE VOLUME: 16,000 CY INCLUDING
1-FT OVERDREOGE ALLOWANCE. SCALE IN FEET
PURPOSE· TO RESTORE SAFE NAVIGATION AND
USABILITY OF SEAPLANE BASE FACILITY
I OCATION· LAT:47' 30' 2.44" LONG:122' 1.3' 06.14"
.M.Il.tM... CORPS OF ENGINEERS LOCK DATUM
ADJACENT PROPERTY OWNERS·
1. CITY OF RENTON (SOUTH)
CITY OF RENTON
SEAPLANE BASE MAINTENANCE
DREDGING PROJECT
TYPICAL SECTIONS
PROPOSED· MAINTENANCE DREDGING
UP TO 16,000 CY
lli.;._ LAKE WASHINGTON
AL. CITY OF RENTON
~ KING
w
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2. BILL COLACURCIO JR. (WEST)
.3. WILLIAM COLACURCIO (WEST) APPUCATION BY• CITY OF RENTON SHEET 4 OF 5 JlAlf;. 3/26/12
This page intentionally left blank for printing purposes.
4.1.4.2 Temporary Removal of Dock
The project proposes to temporarily remove the floating dock from the seaplane base in
order to allow access for dredging.
Temporary Dock Removal
Temporary removal of the floating dock will be conducted to allow access for the dredging
work. Removal of the dock will require dismantling of the timber walers and localized
areas of decking and grating. Removal of the dock would involve removal of decking with
hand tools and power tools.
Re-install Pilings and Dock
Once dredging activities have been completed, it is anticipated that at least one pile will
need to be replaced due to damage during dock removal. Piles will slowly be vibrated out,
at a rate that will minimize turbidity impacts. Once piles are vibrated out, piles will be
redriven within its proper alignment to fit back into the dock structure. Piles will be driven
with a vibratory pile driver approximately 30-40 feet into the silty sand substrate. Once
piles are placed, the dock will be reinstalled.
Vibratory pile driving activities (extraction/installation) are anticipated to occur for no more
than four hours over a period of no more than 2 days within the period of proposed in-
water work (November 15th to December 31•1).
4.1.5 Potential Impacts on Water Quality
Prior to construction a TESC Plan and SPCC Plan will be implemented to prevent
violations of surface water quality due to project activities and ensure the project site will
be protected from spills and releases of dangerous waste, problem waste, petroleum
products, and/or hazardous substances. These plans must be prepared by the contractor,
comply with the Highway Runoff Manual (WSDOT 2011) and be provided to the City of
Renton for approval prior to the initiation of construction.
These plans will require the following actions and best management practices for the
dredging work:
• Dredging & Dredge Material Handling Plan document will be developed by the
contractor in coordination with the City. The Plan will include descriptions of
project site specific work equipment, activities, approach and corresponding BMPs
and water quality protection measure that will be implemented for conformance
with the permit requirements and conservation measurements. The Dredge Plan
will be submitted for review prior to attendance at a pre-dredge conference.
• The dredging contractor will be required to attend a pre-dredge conference prior to
starting the dredging work.
• All equipment shall be checked daily for leaks and any necessary repairs made
prior to commencement of work.
• Piles will be extracted/installed slowly; in order to minimize turbidity impacts.
• Once filled with sediment, the clamshell bucket will be raised at a speed
appropriate to reduce the potential of sediment being washed from the bucket. If
turbidity is found to exceed the limits established in the DOEs Section 401 permit,
the dredging contractor shall be instructed to increase cycle time by slowing the
rate of ascent and pausing at the surface of the water.
• In order to minimize the amount of sediment release from the bucket, the clamshell
will be raised and emptied after every bite.
• In order to minimize the amount of dredge bites needed to remove sediment from
the area of proposed dredge, the contractor shall use the maximum bucket size
practical for site conditions and dredge depth.
• No stockpiling of dredged sediment on the bottom, dragging of the bucket or beam
on the bottom will be allowed.
• The contractor shall use the maximum barge size practical for the dredging
location with appropriate BMPs to contain sediment on the barge. This will include
use of straw bales and silt fencing where applicable.
• The contractor shall not overfill transfer barges and shall have actively maintained
sediment containment systems.
• All debris larger than 2 feet in any dimension will be removed from the dredge
material prior to disposal. Floating debris of similar size will also be collected and
disposed of offsite at an upland facility. A work boat will be onsite to aid in the use
of a debris barrier (if needed) and for rounding up floating debris.
• Dredge positioning utilizing GPS survey instruments will be required in the
construction contract to ensure the dredge work is accomplished in the proper
locations and in the most efficient manner possible. Dredging utilizing special
location tools and techniques will restrict the material dredged to the area and
depths specifically identified.
• If needed for compliance with water quality requirements (as determined during
water quality monitoring), a floating debris boom may be deployed to capture
floating debris dislodged during the dredging operation and to aid in containment
of suspended sediment.
• To ensure compliance with the standards outlined in the DOE's Section 401
permit, qualified personnel will be on-site monitoring for turbidity during the
installation/removal of pilings and during all dredging activities.
• Vibratory pile driving activities (extraction/installation) are anticipated to occur for
no more than four hours over a period of no more than 2 days.
Due to the aforementioned actions, no impacts to water quality are anticipated to exceed
the water quality standards set forth in the Water Quality Standards of Surface Waters of
the State of Washington and/or the 401 permit issued by the DOE (DOE 2006).
4.1.6 Post-Project Site Restoration
There will be no post-project restoration as part of this project. Disturbance of vegetation
is not anticipated as all work is anticipated to be performed from barges, from the existing
dock, or from the airport tarmac.
4.2 Conservation Measures
The following will be implemented in order to minimize project impacts on listed species.
4.2.1 Site and Equipment Preparation
• Implementation of the TESC and SPCC Plans.
l'
4.2.2 Construction Methods and Timing
• All work below OHW will take place during the work window agreed upon by the
USAGE (July 15th-July 31st and November 15th to December 31't)
• Vibratory pile extraction/installation activities will occur for no more than four hours
over a period of no more than two days.
• All waste materials will be fully contained and disposed of offsite in accordance
with federal, state, and local laws.
4.3 Operations
Once project activities are completed, there will be no change in the operation of the
Seaplane Base.
4.4 Maintenance
The City of Renton will continue to maintain the Seaplane Base.
Chapter 5 Project Action Area
5.1 Limits of an Action Area
The limits of the action area are affected by site and project-specific conditions. The
action area for a project encompasses the extent of all direct and indirect effects of a
project that affect both terrestrial and/or aquatic species.
The project would require the removal and installation of at least one pile with a vibratory
pile extractor as well as the removal of approximately 16,000 cubic yards of silty sand,
and the deposit of dredged materials in Elliot Bay, at an USAGE approved open water
disposal site. Elevated sound pressure levels (SPLs) resulting from vibratory pile driving
activities will be the farthest reaching project impact. Therefore, SPLs were used to
determine the terrestrial portion of the action area as well as the aquatic portion of the
action area.
5.1.1 Zone of Terrestrial Impacts
The noise element is generally the farthest-reaching impact from construction activities
and can adversely affect wildlife in various ways. Therefore, noise is used to determine
the terrestrial portion of the action area. For terrestrial animals, sound is measured in
dBA, or A-weighted, this deemphasizes the upper and lower portions of the frequency
spectrum, while emphasizing the middle portion of the spectrum (where humans have the
greatest sensitivity).
According to the noise calculations performed, using WSDOT guidance, increased dBA's
created from vibratory pile driving activities will become indistinguishable from ambient
levels of 55-dBA, approximately 3,459 feet (0.66 mile) from the proposed piles within the
surrounding area (WSDOT 2010a)(Appendix E). Vibratory pile driving activities are
anticipated to occur for a period of approximately four hours over a period of no more than
2 days. General construction activities will become indistinguishable from ambient levels
of 55-dBA, approximately 868 feet (0.16 mile) from the project area.
5.1.2 Zone of Aquatic Impacts
The removal of and installation of piles during the reconstruction of the dock, and the
removal of recently deposited sediment from the seaplane base will require in-water
work".
The aforementioned activities may; therefore, result in a temporary increase in
sedimentation and/or turbidity levels. Additionally, pile driving activities may result in
increased sound pressure levels. These activities could potentially impact listed species
by frightening fish away from the area; temporarily increasing localized competition for
resources.
Sedimentation/turbidity impacts are not expected to exceed the water quality standards
set forth in the 401 permit from the DOE due to the nature of the sediment being dredged
and the dredging methods employed. Sediments to be dredged are composed primarily
of fine to medium sands with a few pockets of sandy silt within the inner shore areas of
the dredge prism. BMPs outlined in Section 4.1 will be implemented to ensure the
dredging work is conducted in accordance with the Water Quality Certification
requirements.
The extent of possible impacts would be limited to the area within 150 feet of dredging
and barge loading activities.
" Impacts of depositing dredged materials in Elliot Bay are not assessed in this biological assessment as these actions are covered
under the 2010 NMFS issued Endangered Species Act (ESA) section 7(a)(2) Biological Opinion and Magnuson Stevens Fishery
Conservation and Management Act Essential Fish Habitat (EFH) Consultation and the 2011 USFWS issued concurrence letter for the
Puget Sound Dredge Disposal Analysis (PSDDA) Program.
The practical spreading loss model was used to determine where underwater SPLs
created from vibratory pile extraction/installation (171 PEAK or 155 RMs") will become
indistinguishable from ambient levels of 150PEAK or 135RMs" (WSDOT 201 Oa) .. Using this
model it was determined that vibratory pile driving construction noise will become
indistinguishable approximately 706 feet (0.13 mile) from a pile being extracted/installed.
See Appendix E for information on how this distance was calculated.
As landmasses are known to hinder the forward movement of elevated SPLs within water,
only those areas within line of sight of the proposed pile removal/installation were included
within the aquatic portion of the action area. Therefore, while noise levels will be elevated
within 706 feet (0.13 mile) from a pile being extracted/installed piles within Lake
Washington these SPLs would not be elevated within the Cedar River.
Since the aquatic portion of the action area is defined by the furthest boundary in which
impacts may occur to fish, this area will encompass the area within includes all waters
within 150 feet of all dredging and barge loading activities and/or 706 feet (0.13 mile) of
any pile being extracted/installed.
5.2 Defining an Action Area
The action area encompasses all areas that could potentially be affected directly or
indirectly by the proposed project and is not limited to the actual construction area (project
area). The action area (terrestrial portion) for this project would include all areas within
3,459 feet (0.66 mile) of a pile being extracted/installed (for up to four hours over no more
than 2 days) during vibratory pile driving activities and within 706 feet (0.13 mile) from the
project area during general construction. Additionally the action area (aquatic portion)
includes all waters within 150 feet of all dredging and barge loading activities (for up to
160 hours over no more than 20 days) or the area within 706 feet (0.13 mile) of any pile
being extracted/installed (for up to four hours over no more than 2 days)(Figure 5).
"CalTrans. 2007. Conmendium of Pile Driving Sound Data. September 27.
"Guidanoe from Chapter 7: Construction Noise Impact Assessment of the 2010 WSDOT Biological Assessment Preparation
Advanced Training Manual for Transportation Projects Manual was used to approximate ambient noise in the project area. The
guidanoe states "Background sound levels in deep freshwater lakes or deep slow moving
rivers are approximately 135 dBRMS.".
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Zone of Terrestrial Impacts Zone of Aquatic Impacts
0 Elevated SPLs (Vibratory Pile Driving ) Elevated Turbidity
0 Elevated SP Ls (General Construction) [I Elevated SP Ls
-'"'--'--n:. ·--
0 0.5 ------======:i Miles
0 .2 5
Figure 5: Action Area
Seaplane Base Improvements Project
City of Renton
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'
Chapter 6 Effects Analysis
6.1 Direct Effects
6.1.1 Underwater Vibrations
Sound pressure levels above 150 dBrms have been noted to cause temporary behavioral
changes such as darting/startling or other behavior associated with stress. Fatal impacts
to fish are not anticipated within the aquatic portion of the action area. Sound pressure
levels above 150 dBrms have been noted to cause temporary behavioral changes such as
darting/startling or other behavior associated with stress. During pile driving/extraction
activities, fish may be frightened away from the project area forcing them to forage in
other areas. While a measureable change in underwater noise will affect a 0.13 mile
area, fish will only be affected by increased underwater vibrations, created from vibratory
pile driving activities, may within 0.01 mile (71 feet) of a pile (Appendix E). The line of
sight rule, is also used when determining the extent of project related noise as noise may
only propagate to the extent of an area that is within line of sight. Therefore, potential
behavior modification offish will be limited to the area within Lake Washington and will not
include the Cedar River. Vibratory pile extraction/installation is anticipated to occur for no
more than four hours over a period of no more than 2 days" within the period of proposed
in-water work (November 161h to December 31 51). The effects to fish created by these
activities are discountable as it occurs over a short duration and in a very limited space.
14 Four hours is the maximum amount of ~me in-which piles can be driven/extracted.
6.1.2 Water Quality
Sedimentation/Turbidity
The effects of turbidity on anadromous fish can be classified as behavioral, sublethal, or
lethal depending on the level of turbidity (USACE 2005).
Behavioral effects result in changes in activity darting/startling or other behavior
associated with stress. Turbidity also limits fish vision, which can interfere with social
behavior, foraging, and predator avoidance (Meager and Utne-Palm 2008).
Sublethal effects relate to tissue injury or alteration in physiology. These affects are
chronic in nature and while not leading to immediate death, they may result in morality
over time. These effects include gill trauma, and /or impacts to blood chemistry,
reproduction or growth (USACE 2005).
Lethal effects kill individual fish and can cause overall population reductions. Suspended
sediment levels high enough to kill fish are not attained in either the natural estuarine
environment or during dredging operations (USACE 2005). Since dredging will be
completed using mechanical means, primarily by means of a clamshell it is unlikely that
the dredging would cause direct mortality to fish. Specifically, the clamshell bucket
descends to the substrate in an open position. During the descent, the bucket remains in
an open position and, thus, would be unlikely to trap or contain fish (USACE 2002).
It has been shown that salmonids will move to less turbid waters, if available, after a short-
term impulse. It has been illustrated that as little as 25 NTUs of turbidity may cause
reduction in fish growth. Increases in gill flaring have been reported after short-terms
sediment pulses of 60 NTU. Salmonids are displaced from waters with turbidities greater
than 70 NTUs. Above 150 NTU, juvenile Chinook salmon exhibit reduced feeding
regardless of prey type and forager size, thus reducing production of fish populations
(Bash et. al. 2001).
Short-term impacts to water quality may occur as a result of increased turbidity during the
extraction/installation of piles and/or the removal of recently deposited sediment from the
seaplane base. These activities will result in the re-suspension of sediments; increasing
turbidity.
According to the USACE's technical report, The Four Rs of Environmental Dredging:
Resuspension, Release, Residual, and Risk, data from the most comprehensive studies
show re-suspension rates for bucket dredges are generally less than 1 percent without
barge overflow (USAGE 2008). Re-suspension from a clamshell occurs throughout the
water column resulting in a bimodal distribution, with peaks at the bottom and top of the
water column (USAGE 2008).
Sedimentation/turbidity impacts are not expected to exceed the water quality standards
set forth in the 401 permit from the DOE due to the nature of the sediment being dredged
and the dredging methods employed.
A water quality monitoring plan will be developed by the City prior to the start of
construction and submitted with the Pre-dredge plan for review by the regulatory
agencies. The water quality monitoring plan will include the following elements:
• Description of equipment, method, frequency, location, and depth of water quality
sampling.
• Personnel responsible for performing the monitoring the work and contact
information.
• Turbidity monitoring reports will be sent to the permit coordinator on a weekly
basis.
• City and Contractor will notify the permit contractor within 24 hours if an
exceedance occurs.
Turbidity monitoring will be conducted at the 100ft mixing zone boundary as an indicator
of dredging work turbidity and potential need to modify BMPs or dredging methods as part
of adaptive management. In the event it appears an exceedance could occur based on
data collected from the mixing zone boundary, the Contractor will adjust work methods to
ensure they will avoid exceedances of water quality at the compliance boundary. The
following is a list of additional BMPs and contingency measures that may be employed in
the event the possibility of an exceedance were to occur:
• Dredge operator may pause the bucket at the surface after its ascent through the
water column to minimize turbidity by allowing free water to drain from the bucket
prior to swinging the bucket to the barge.
• The rate of ascent and decent of clamshell bucket may be slowed to reduce
potential sediment loss.
• If barge dewatering is a factor, additional filter material may be used on the
barges in an effort to reduce suspended sediment in the decant water.
• Utilize a closed clamshell bucket if it determined that the dredge sediment is in a
loose state that such a bucket would be effective in dredging.
• Temporarily increase water quality measurements to ensure contingency
measures are successful in reducing turbidity.
It is anticipated that project activities may; therefore, result in behavioral effects to fish
such as reducing in-water visibility, clogging fishes' gills, potentially reducing growth and
displacing fish; forcing them to forage in other areas. However, instantaneous fish kills
are not anticipated to result from proposed project activities.
Chemical Contaminants
During dredging activities the disturbance of sediments may result in the release of
contaminants from sediment pore water and sediment particles. These resuspended
chemical contaminants may be adsorbed to resuspended particles, may partition to the
water column, or may be released into the air. As the sediment to be dredged from the
Seaplane Base site does not have contaminants exceeding sediment management
standards set by RSET, any such resuspension is anticipated to be de minimus.
6.1.3 Substrate Redistribution
The project proposes to remove approximately 16,000 cubic yards (CY) of recently
deposited silty sand substrate from a 48,000 square foot (sq ft) area adjacent to the
seaplane base. Removal of this material will return the lakebed habitat surrounding the
seaplane base to an elevation of 8.5 feet.
Dredged materials will be deposited in Elliot Bay, at an USAGE approved open water
disposal site.
6.1.4 Shading
The project will temporarily shade an approximately 9,500 square foot area due to the
placement of a barge; however, as the barge will be moved every few hours, no impacts
are anticipated, as predators prefer to hide under stationary structures.
6.1.5 Organic Inputs
Organic inputs such as leaf litter are an important food source to aquatic invertebrates,
which are in turn are an important food source to fish. Dredging of the substrate may
temporarily decrease organic inputs within the aquatic portion of the action area, as any
aquatic plants within the area of dredge removal/placement will be uprooted. However,
over time these aquatic plants will reestablish naturally.
6.1.6 Wetlands
The proposed project will not impact any of the wetlands as there are no wetlands within
the project area as referenced in Section 3.2.3.
6.2 Indirect Effects
6.2.1 Predator-Prey Relationships
Forage Fish
During the time of in-water work (November 15th -December 31'1) prey species such as
coho salmon, cutthroat trout, and rainbow trout may all be rearing/foraging within the
aquatic zone of the action area. Dredging activities and pile extraction/installation are
expected to produce a temporary increase in sedimentation and turbidity levels potentially
resulting in behavioral effects to fish. Prey species may be temporarily displaced from the
aquatic portion of the action area .. Turbidity will be minimal, localized, and temporary and
therefore, any behavioral responses elicited by listed fish or prey species would be
insignificant. Impacts are not expected to exceed the water quality standard set forth in
the 401 permit from the DOE.
6.3 Interrelated and Interdependent Actions
No interrelated or independent actions are anticipated as a result of this project.
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Chapter 7 Effect Determinations
7 .1 Effect Determinations for Listed Species
7.1.1 Coastal/Puget Sound DPS of Bull Trout
(USFWS: Threatened)
The project "may affect" the Coastal/Puget Sound DPS of bull trout for the following
reasons:
• Bull trout have access to the aquatic portion of the action area year round.
• Prey species are anticipated to be present in the action area during construction.
• The extraction/installation of steel pipe piles may result in elevated SPLs within the
area approximately 0.16 mile (824 ft) of a pile being extracted/installed.
• Short-term impacts to water quality may occur within 0.31 mile of dredging
activities as a result of an increase in sedimentation/turbidity.
• Dredging activities may result in the release of contaminants from sediment pore
water and sediment particles.
• The project will temporarily shade an approximate 9,500 sq ft area due to the
placement of a barge.
• Dredging of the substrate may temporarily decrease organic inputs within the
aquatic portion of the action area as any aquatic plants within the area of dredge
removal/placement will be uprooted.
• Any prey species present during the time of in-water work may be temporarily
displaced from the within the aquatic portion of the action area.
The project "is not likely to adversely affect" bull trout for the following reasons:
• There is no viable population of bull trout known to inhabit Lake Washington.
• Vibratory pile extraction will occur for no more than four hours in two days. Fish
may be frightened away from the area of elevated SPLs during this time; however,
as this area is surrounded by other high quality aquatic habitat and the proposed
in-water work is so short in duration any impacts resulting from elevated SP Ls are
anticipated to be insignificant.
• Turbidity will be minimal, localized, and temporary and therefore, any behavioral
responses elicited by listed fish or prey species would be insignificant. Impacts
are not expected to exceed the water quality standard set forth in the 401 permit
from the DOE.
• The Seaplane Base does not have contaminants exceeding sediment
management standards set by RSET, any such resuspension is anticipated to be
de minimis.
7.1.2 Puget Sound ESU of Chinook Salmon
(NMFS: Threatened)
The project "may affect" the Puget Sound ESU of Chinook salmon for the following
reasons:
• Adult fall Chinook salmon are known to upmigrate through the aquatic portion of
the action area and juvenile Chinook are known to utilize the area for rearing and
outmigration.
• The extraction/installation of steel pipe piles may result in elevated SPLs within the
area approximately 0.13 miles (706 ft) of a pile being extracted/installed.
• Short-term impacts to water quality may occur within 0.31 miles of dredging
activities as a result of an increase in sedimentation/turbidity.
• Increases in turbidity may result in behavioral effects to fish -reducing in-water
visibility, clogging fishes' gills, and reducing feeding; forcing them to forage
temporarily in other areas.
• Dredging activities may result in the release of contaminants from sediment pore
water and sediment particles.
• The project will temporarily shade an approximate 9,500 sq ft area due to the
placement of a barge.
• Dredging of the substrate may temporarily decrease organic inputs within the
aquatic portion of the action area as any aquatic plants within the area of dredge
removal/placement will be uprooted.
• Any prey species present during the time of in-water work may be temporarily
displaced from the within the aquatic portion of the action area.
The project "is not likely to adversely affect" Chinook salmon for the following reasons:
• Based on project timing, the likelihood of juvenile Chinook presence within the
action area during construction is discountable.
• Vibratory pile extraction will occur for no more than four hours in two days. Fish
may be frightened away from the area of elevated SPLs during this time; however,
as this area is surrounded by other high quality aquatic habitat and the proposed
in-water work is so short in duration any impacts resulting from elevated SP Ls are
anticipated to be insignificant.
• Turbidity will be minimal, localized, and temporary and therefore, any behavioral
responses elicited by listed fish or prey species would be insignificant. Impacts
are not expected to exceed the water quality standard set forth in the 401 permit
from the DOE.
• The Seaplane Base does not have contaminants exceeding sediment
management standards set by RSET, any such resuspension is anticipated to be
de minimis.
7.1.3 Puget Sound DPS of Steelhead Trout
(NMFS: Threatened)
The project "may affect" the Puget Sound DPS of steelhead trout for the following
reasons:
• Both juvenile and adult steelhead may be migrating through the aquatic portion of
the action area during the time of proposed in-water work (November 16'" -
December 31 '1).
• The extraction/installation of steel pipe piles may result in elevated SPLs within the
area approximately 0.13 miles (706 fl) of a pile being extracted/installed.
• Short-term impacts to water quality may occur within 0.31 mile of dredging
activities as a result of an increase in sedimentation/turbidity.
• Increases in turbidity may result in behavioral effects to fish -reducing in-water
visibility, clogging fishes' gills, and reducing feeding; forcing them to forage
temporarily in other areas.
• Dredging activities may result in the release of contaminants from sediment pore
water and sediment particles.
• The project will temporarily shade an approximate 9,500 sq ft area due to the
placement of a barge.
• Dredging of the substrate may temporarily decrease organic inputs within the
aquatic portion of the action area as any aquatic plants within the area of dredge
removal/placement will be uprooted
• Any prey species present during the time of in-water work may be temporarily
displaced from the within the aquatic portion of the action area.
The project "is not likely to adversely affect" steelhead trout for the following reasons:
• Vibratory pile extraction will occur for no more than four hours in two days. Fish
may be frightened away from the area of elevated SP Ls during this time; however,
as this area is surrounded by other high quality aquatic habitat and the proposed
in-water work is so short in duration any impacts resulting from elevated SPLs are
anticipated to be insignificant.
• Turbidity will be minimal, localized, and temporary and therefore, any behavioral
responses elicited by listed fish or prey species would be insignificant. Impacts
are not expected to exceed the water quality standard set forth in the 401 permit
from the DOE.
• The Seaplane Base does not have contaminants exceeding sediment
management standards set by RSET, any such resuspension is anticipated to be
de minimis.
Table 3: Summary of listed species activities and construction periods
Month I January I February I March
Site Preparation
Mobilization
Upland Staging
Beneficial Reuse Site Preparation
Construction
Dredge Basin
Deposit Dredge
Replace Dock
Designated In-Water Work Window
Proposed In-Water Work
Listed species activity periods
Bull trout (no viable populations known to occur)
Fall Chinook upmigration through
Lake Washington
Fall Chinook spawning
Fall Chinook incubation
Fall Chinook rearing
Fall Chinook outmigration through
Lake Washington
Winter steelhead upmigration through
Lake Washington
Winter steelhead spawning
Winter steelhead incubation
Winter steelhead rearing
Winter steelhead outmigration through
Lake Washington
(Kerwin 2001)
N/A N/A N/A
April May June July August September October November I December
N/A N/A N/A N/A N/A NIA N/A N/A N/A
7 .2 Analysis of Effects to Critical Habitat Primary
Constituent Elements
The USFWS defines critical habitat; as areas that contain Primary Constituent Elements
(PCEs) required by a species. PCEs are those physical and biological features of a
landscape that a species needs to survive.
7 .2.1 Designated Critical Habitat for the Coastal/Puget Sound DPS
of Bull Trout
The following discussion addresses the nine essential PCEs for proposed bull trout critical
habitat and the associated assessment for each element.
• "Springs, seeps, groundwater sources, and subswface water connectivity to
contribute to water quality and quality and provide thermal refugia:
No such features are located within the aquatic portion of the action area;
therefore, none will be affected by the proposed project activities.
• Migratory habitats with minimal physical, biological, or water quality impediments
between spawning, rearing, overwintering, and freshwater and marine foraging
habitats, including but not limited to permanent, partial, intermittent, or seasonal
barriers.
The proposed project 'may impact' migratory habitat within the aquatic portion of
the action area.
• An abundant food base, including terrestrial organisms of riparian origin, aquatic
macroinvertebrates, and forage fish.
The proposed project 'may impact' food sources within the aquatic portion of the
action area.
• Complex river, stream, lake, reservoir, and marine shoreline aquatic environments
and processes that establish and maintain these aquatic environmental, with
features such as large wood, side channels, pools, undercut banks, and
unembedded substrates, to provide a variety of depths, gradients, velocities, and
structure.
The project 'may impact' substrate within the aquatic portion of the action area.
• Water temperatures ranging from 2 to 15'C (36 to 59'F), with adequate thermal
refugia available for temperatures that exceed the upper end of this range.
Specific temperatures in this range will depend on bull trout life-history stage and
form; geography; elevation; diurnal and seasonal variation; shading; such as that
provided by riparian habitat; streamflow; and local groundwater influence.
The proposed project is not anticipated to impact temperatures within the aquatic
portion of the action area.
• In spawning and rearing areas, substrate of sufficient amount, size, and
composition to ensure success of egg and embryo overwinter survival, fry
emergence, and young-of-the-year and juvenile survival. A minimal amount of fine
sediment, generally ranging in size from sift to coarse sand, embedded in larger
substrates, is characteristic of these conditions. The size and amounts of fine
sediment suitable to bull trout will vary from system to system.
No spawning or rearing areas are located within the aquatic portion of the action
area; therefore, none will be affected by the proposed project activities.
• A natural hydrograph, including peak, high, low, and base flows within historical
and seasonal ranges or, if flows are controlled, they minimize departures from a
natural hydrograph.
The proposed project is not anticipated to affect the natural hydrograph within the
aquatic portion of the action area.
• Sufficient water quality and quantity such that normal reproduction, growth, and
survival are not inhibited.
The proposed project 'may impact' water quality within the aquatic portion of the
action area.
• Sufficiently low levels of occurrence of nonnative predatory (e.g., lake trout,
walleye, northern pike, smallmouth bass); interbreeding (e.g. brook trout); or
competing (e.g. brown trout) species that, if present, are adequately temporally
and spatially isolated from bull trout.
The proposed project is not anticipated to affect the occurrence of nonnative
predatory, interbreeding or competing species within the aquatic portion of the
action area.
Lake Washington is designated critical habitat for the Coastal/Puget Sound DPS of bull
trout. The project will require some in-water work. The in-water work area is not within
documented bull trout habitat; however, as no physical barriers exist which would prevent
fish from entering the lake the area is designated as critical habitat". The project may
cause only limited short-term adverse effects to bull trout critical habitat, primarily by
affecting potential foraging habitat:
• Dredging activities will temporarily increase sedimentation/turbidity within the
aquatic portion of the action area; These activities are short-term impacts to water
quality. Impacts are not expected to exceed the water quality standard set forth in
the 401 permit from the DOE. No long-term water quality impacts are anticipated.
• Dredging activities may result in the release of contaminants from sediment pore
water and sediment particles; however, as the seaplane base does not have
contaminants exceeding sediment management standards set by RSET, any such
resuspension is anticipated to be de minimis.
• Dredging of the substrate will temporarily decrease organic inputs within the
aquatic portion of the action area as any aquatic plants within the area of dredge
removal/placement will be uprooted. However, over time these aquatic plants will
reestablish naturally.
• Dredging activities are expected to produce behavioral effects to fish due to
increases in sedimentation and turbidity levels. Prey species may be temporarily
displaced from the aquatic portion of the action area and forced to forage in other
areas. However, this impact is expected to be insignificant given the short duration
and limited area affected. The project area is surrounded by other high quality
aquatic habitat that can be utilized during project activities.
"It should be noted a possible thermal barrier may be present from July 15• -September 15'"·
• The project proposes to remove approximately 16,000 cubic yards (CY) of recently
deposited silty sand substrate from a 48,000 square foot (sq ft) area adjacent to
the seaplane base. Dredged materials will be deposited in Elliot Bay, at an
USAGE approved open water disposal site.
Based on the above discussion, the project "may affect, not likely to adversely
affect" listed critical habitat for the DPS of Coastal/Puget Sound bull trout.
7.2.2 Designated Critical Habitat for the Puget Sound ESU of
Chinook Salmon
The following discussion addresses the six essential PCEs for steelhead trout critical
habitat and the associated assessment for each element.
• "Freshwater spawning sites with water quantity and quality conditions and
substrate supporting spawning incubation and larval development. These
features are essential to conservation because without them the species cannot
successfully spawn and produce offspring."
No such spawning sites are located within the aquatic portion of the action area;
therefore, none will be affected by the proposed project activities.
• "Freshwater rearing sites with water quantity and floodplain connectivity to form
and maintain physical habitat conditions and support juvenile growth and mobility;
water quality and forage supporting juvenile development; and natural cover such
as shade, submerged and overhanging large wood, log jams and beaver dams,
aquatic vegetation, large rocks and boulders, side channels, essential to
conservation because without them juveniles cannot access and use the areas
needed to forage, grow, and develop behaviors (e.g., predator avoidance,
competition) that help ensure their survival."
The proposed project 'may impact' water quality and forage within freshwater
rearing sites.
• "Freshwater migration corridors free of obstruction with water quantity and quality
conditions and natural cover such as submerged and overhanging large wood,
aquatic vegetation, large rocks and boulders, side channels, and undercut banks
supporting juvenile and adult mobility and survival."
The project 'may impact' water quality within freshwater migration corridors.
• The final three PCEs pertain to offshore, nearshore marine areas and estuarine
habitat which does not exist in the project action area.
Lake Washington is critical habitat for the Puget Sound ESU of Chinook salmon. The
project will require some in-water work. The proposed project 'may impact' rearing, and/or
migratory habitat. The project would cause only limited short-term adverse effects to
Chinook salmon critical habitat, primarily by affecting possible rearing habitat:
• Dredging activities will temporarily increase sedimentation/turbidity within the
aquatic portion of the action area; these activities are short-term impacts to water
quality. Impacts are not expected to exceed the water quality standard set forth in
the 401 permit from the DOE. No long term water quality impacts are anticipated.
• Dredging activities may result in the release of contaminants from sediment pore
water and sediment particles; however, as the seaplane base does not have
contaminants exceeding sediment management standards set by RSET, any such
resuspension is anticipated to be de minimis.
• Dredging of the substrate will temporarily decrease organic inputs within the
aquatic portion of the action area as any aquatic plants within the area of dredge
removal/placement will be uprooted. However, over time these aquatic plants will
reestablish naturally.
• Dredging activities are expected to produce behavioral effects to fish due to
increases in sedimentation and turbidity levels. Prey species may be temporarily
displaced from the aquatic portion of the action area and forced to forage in other
areas. However, this impact is expected to be insignificant given the short duration
and limited area affected. The project area is surrounded by other high quality
aquatic habitat that can be utilized during project activities.
• The project proposes to remove approximately 16,000 cubic yards (CY) of recently
deposited silty sand substrate from a 48,000 square foot (sq ft) area adjacent to
the seaplane base. Dredged materials will be deposited in Elliot Bay, at an
USAGE approved open water disposal site.
Based on the above discussion, the project "may affect, is not likely to adversely
affect" listed critical habitat for the ESU of Puget Sound Chinook Salmon.
,, i 1;
Chapter 8 References
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____ 2011. Temperature Data for Site 08C070 -Cedar R@ Logan St/Renton.
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ESA (Endangered Species Act, as amended). 2002. Endangered Species Act of 1973. As
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Franklin, J.F., Dyrness, C.T.. 1973. Natural Vegetation of Oregon and Washington.
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Kerwin, John. 2001. Salmon and Steelhead Habitat Limiting Factors Report for the
Cedar-Sammamish Basin. Washington State Conservation Commission.
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http://www.kinqcounty.gov/environment/animalsAndPlants/salmon-and-
troutlidentification/steelhead.aspx
___ . 2010. Major Lakes Monitoring. King County Water and Land Resource
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http://green.kingcounty.gov/lakes/LakeWashinqton.aspx
Meager, J. J. & Utne-Palm, A. C. 2008. Effect of turbidity on habitat preference of
juvenile Atlantic cod, Gadus morhua0 Environ. Bio.I Fish. 81: 149-155.
'"i ,.
NMFS (National Oceanic and Atmospheric Administration, National Marine Fisheries
Service). 1996. Magnuson Stevens Fishery Conservation and Management Act.
October. Accessed March 30, 2007.
http://www.nmfs.noaa.gov/sfa/magact/
___ . 2005. Endangered and threatened Species (ETWP); Designation of Critical
Habitat for 12 Evolutionary Significant nits of West Coast Salmon and Steel head in
Washington. Oregon, and Idaho. September 2. Federal Register 70 (170): 52630-
52858.
___ . 2007. Endangered and Threatened Species: Final Listing Determination for
Puget Sound Steel head. May 11. Federal Register 72 (91 ): 26722-26734.
___ . 2011 a. Endangered Species Act Status of West Coast Salmon and Steel head.
National Marine Fisheries Service, Northwest Regional Office. Last revised
August 11. Accessed April 12, 2012.
http://www.nwr.noaa.gov/Species-Lists.cfm
___ . 2011 b. Environmental History and Features of Puget Sound. Northwest
Fisheries Science Center.
http://www.nwfsc.noaa.gov/publications/techmemos/tm44/environment.htm
Shellberg, Jeffery. 2002. Bull trout in Western Washington. January. The Water Center:
University of Washington. Accessed April 25, 2007.
http://depts.washington.edu/cwws/Outreach/FactSheets/bulltrout.pdf
Tabor, R. A., and R. M. Piaskowski. 2002. Nearshore habitat use by juvenile Chinook
salmon in lentic systems of the Lake Washington Basin, Annual Report, 2001.
U.S. Fish and Wildlife Service, Western Washington Office. Division of Fisheries
and Watershed Assessment. Accessed January 13, 2011.
http://www.fws.gov/wafwo/fisheries/publications/fp226.pdf
Tabor et. a/ (Tabor, R. A, J_ A. Scheurer, H. A. Gearns, and E. P. Bixler). 2004.
Nearshore habitat use by juvenile Chinook salmon in lentic systems of the Lake
Washington Basin, Annual Report, 2002. U.S. Fish and Wildlife Service, Western
Washington Office. Division of Fisheries and Watershed Assessment. Accessed
January 13, 2011.
http://www.fws.gov/wafwo/fisheries/publications/fp222.pdf
Tabor et. al (Tabor, R. A., H. A. Gearns, C. M. McCoy Ill, and S. Camacho). 2006.
Nearshore habitat use by juvenile Chinook salmon in lentic systems of the Lake
Washington Basin, Annual Report, 2003 and 2004. U.S. Fish and Wildlife Service,
Western Washington Office. Division of Fisheries and Watershed Assessment.
Accessed January 13, 2011.
http://www.fws.gov/wafwo/fisheries/Publications/FP233.pdf
USAGE (United States Army Corps of Engineers). 2002. Appendix G-Endangered
Species Act Consultation for Non-anadromous Fish and Terrestrial Species in
Dredged Material Management Plan and Environmental Impact Statement for the
McNary Reservoir and Lower Snake River Reservoirs. Walla Walls District. July.
___ . 2005. Biological Assessment: FY 2007-2011 Maintenance Dredging Turning
Basin and Navigation Channel Upper Duwamish Waterway. CENWS-PM-PL-ER.
November 17.
___ . 2010. Chinook Salmon, Steel head Trout, and Bull Trout Work Windows for the
Lake Washington System. Accessed April 11, 2012.
http://www.nws.usace.army.mil/PublicMenu/documents/REG/Lake WA System
Work Windows 2010-03-09 .pdf
___ ,. 2011. Sediment Quality Guidelines for Standard Chemicals of Concern.
Regional Sediment Evaluation Team. Accessed January 17, 2010
http://www.nws.usace.army.mil/PublicMenu/Menu.cfm?sitename=DMMO&pagena
me=RSET
USFWS (United States Fish and Wildlife Service). 1999a. ETWP; listing of nine
evolutionarily significant units of Chinook salmon, Chum salmon, Sockeye salmon,
and Steelhead. September 2. Federal Register 64 (14 7): 41835-41839.
___ . 1999b. ETWP; Determination of Threatened Status for Bull Trout in the
Conterminous United States. November 1. Federal Register 64 (210): 31740.
___ . 2005a. ETWP; Designation of Critical Habitat for the Bull Trout; Final Rule.
September 26. Federal Register 70 (185): 56304
___ . 2005b. Critical Habitat: What is it? December. Endangered Species Program.
Accessed December 16, 2009.
http://www.fws.gov/endangered/pdfs/listing/Critical Habitat 12 05. pdf
___ . 201 Oa. ETWP; Revised Designation of Critical Habitat for Bull Trout in the
Coterminous United States; Final Rule. October 18. Federal Register 75 (200):
63897-64070.
___ . 2011. National Wetlands Inventory. Accessed January 11, 2011.
http://www.fws.gov/wetlands/data/mapper.html
___ . 2012. Listed and Proposed Endangered and Threatened Species and Critical
Habitat; Candidate Species and Species of Concern in King County. Washington
Fish and Wildlife Office. Last Revised March 15. Accessed April 12, 2012.
http://www. fws. gov /wafwo/speciesmap/Ki ngCou nty0312. pdf
WDFW (Washington Department of Fish and Wildlife). 2011a. SalmonScape Web
Application: an interactive mapping application designed to display and report a
wide range of data related to salmon distribution, status, and habitats. January 11,
2011.
http://wdfw.wa.gov/mappinq/salmonscape/
------,-· 2011 b. Salmonid Stock Inventory. WRIA 08 -Lake Washington. Accessed
January 13, 2011.
http://wdfw.wa.gov/conservation/fisheries/sasi/search.php?searchby=WRIA&searc
h=08&orderby=Species%20ASC, %20StockName%20ASC
WSDOT (Washington State Department of Transportation). 2011. Highway Runoff
Manual. M31-16.03. Environmental and Engineering Programs Design Office.
November.
2010a. Chapter 7: Noise Impact Assessment. Biological Assessment
Preparation for Transportation Projects Advanced Training Manual. Version 02-
2010. February. Environmental Services, Olympia WA.
___ . 201 Ob. Chapter 9: Environmental Baseline within the Action Area. Biological
Assessment Preparation for Transportation Projects Advanced Training Manual.
Version 02-2010. February. Environmental Services, Olympia WA.
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Appendix A: Essential Fish Habitat
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Will Roger-Wiley Post Memorial Seaplane Base
Assessment of Effects on Essential Fish Habitat for Coho, Chinook, and Pink Salmon:
as protected under the Magnuson-Stevens Fishery Conservation and Management Act
(as amended 1996)
Lake Washington -King County, Washington State
The Magnuson-Stevens Fishery Conservation and Management Act (MSA) includes a
mandate that NMFS must identify essential fish habitat (EFH) for federally managed
marine fishes, and federal agencies must consult with NMFS on all activities, or proposed
activities, authorized, funded, or undertaken by the agency that may adversely affect EFH
(NMFS 1996). The Pacific Fisheries Management Council (PFMC) has designated EFH
for the Pacific salmon fishery, federally managed groundfish, and the coastal pelagic
fisheries (PFMC 1999).
The PFMC defines EFH for the Pacific coast salmon fishery (Puget Sound coho, Chinook,
and pink salmon) as 'those waters and substrate necessary for salmon production needed
to support a long-term sustainable salmon fishery and salmon contributions to a healthy
ecosystem. To achieve that level of production, EFH must include all streams, lakes,
ponds, wetlands, and other currently viable water bodies and most of the habitat
historically accessible to salmon in Washington, Oregon, Idaho, and California', except
above the impassible barriers identified by the PFMC (1999).
The Pacific salmon management unit includes Puget Sound Chinook (Oncorhynchus
tshawytscha), coho (Oncorhynchus kisutch), and pink salmon (Oncorhynchus gorbuscha).
Chinook and coho salmon have been documented as being present within the aquatic
portion of the action area.
Salmon need freshwater habitat that includes cool, clean water of appropriate water depth
and flows, upland and riparian vegetation to stabilize soil and provide shade, clean gravel
for spawning and egg-rearing, large woody debris to provide resting and hiding places,
adequate food, and pool-riffle complexes (USAGE 2010).
The aquatic portion of the action area is utilized for migration by Chinook salmon.
Chinook salmon spawn outside of the aquatic portion of the action area, in the Cedar
River at river mile (RM) 1.0 (WDFW 2011 ). Juvenile fall Chinook are known to rear within
the aquatic portion of the action area, in very shallow water ( <3 ft) on unvegetated, sandy-
gravel beach portions of the shoreline (Tabor and Piaskowski 2002, McCoy et al. 2003).
Fall Chinook migrate through Lake Washington to spawning grounds Mid-June through
early November, spawning mid-September through, and out-migrating January through
August (Kerwin 2001 ). During the time of in-water work (November 15th -December 31st)
it is not anticipated that Chinook salmon will be present within the aquatic portion of the
action area as adults will have migrated to freshwater tributaries to spawn and juveniles
will have already outmigrated to the ocean.
Spring and Summer Chinook are not anticipated to be present within Lake Washington as
there are no records of spring or summer Chinook salmon occurring within the area.
The aquatic portion of the action area is utilized for migration by coho salmon. Coho
salmon spawn outside of the aquatic portion of the action area, in the Cedar River at RM
0.2 (WDFW 2011 ). Coho salmon are known to rear in the mouth of the Cedar River, also
outside the aquatic portion of the action area (WDFW 2011 ). Coho migrate through Lake
Washington to spawning grounds from August to early December, spawning November
through early December, and rearing 12-14 months before out-migrating thorough Lake
Washington to the ocean (Kerwin 2001 ). During the time of in-water work (November 15th
-December 31't) adult coho may be migrating through Lake Washington on their way to
spawning grounds though juveniles will have likely already outmigrated to the ocean.
Essential fish habitat for the Pacific salmon fishery is present in the aquatic portion of the
action area. Conservation measures will be in place such as: implementation of erosion
control best management practices; and a Spill Prevention Control and Countermeasures
Plan. The proposed project will also implement minimization measures.
Dredging activities may temporarily increase sedimentation/turbidity within the aquatic
portion of the action area. Impacts are not expected to exceed the water quality standard
set forth in the 401 permit from the DOE. These activities are short-term impacts to water
quality. No long-term water quality impacts are anticipated.
Dredging activities may also result in the release of contaminants from sediment pore
water and sediment particles; however, as the seaplane base does not have contaminants
exceeding sediment management standards set by RSET, any such resuspension is
anticipated to be de minimis.
The project proposes to remove approximately 15,000 cubic yards (CY) of recently
deposited silty sand substrate from a 48,000 square foot (sq ft) area adjacent to the
seaplane base. Dredged materials will be deposited in Elliot Bay, at an USAGE approved
open water disposal site.
The proposed project; therefore, will not adversely affect EFH. All in-water work will
take place during the USAGE appointed in-water work window (July 15th -July 31st and
November 15th to December 31").
References
Kerwin, John. 2001. Salmon and Steel head Habitat Limiting Factors Report for the
Cedar-Sammamish Basin. Washington State Conservation Commission.
September.
NMFS (National Oceanic and Atmospheric Administration -National Marine Fisheries
Service). 1996. Magnuson Stevens Fishery Conservation and Management Act.
October. Accessed March 30, 2007. http://www.nmfs.noaa.gov/sfa/magact/
PFMC (Pacific Fishery Management Council). 1999. Amendment 14 to the Pacific Coast
Salmon Plan. Appendix A: Description and Identification of Essential Fish
Habitat, Adverse Impacts and Recommended Conservation Measures for Salmon.
August. Accessed April 11, 2007.
http://www. pcouncil. org/salmon/salfmp/a 14/99efh 1.pdf
USAGE (US Army Corps of Engineers). 2010. Chinook Salmon Habitat Requirements.
Accessed July 15, 2010.
http://www.nww.usace.army.mil/salmonriver/chinook.htm
WDFW (Washington Department of Fish and Wildlife). 2011a. SalmonScape Web
Application: an interactive mapping application designed to display and report a
wide range of data related to salmon distribution, status, and habitats. January 11,
2011.
http://wdfw.wa.gov/mappinglsalmonscape/
Appendix B: Detailed Listed Species Info
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BULL TROUT
Bull trout belong to the char subgroup of the salmonid family that includes the Dolly
Varden, lake trout and brook trout (Wydoski and Whitney 2003). High quality bull trout
habitat is typically characterized by cold temperatures; abundant cover in the form of large
wood, undercut banks, and boulders; clean substrate for spawning; interstitial spaces
large enough to conceal juvenile bull trout; and stable channels (Shellberg 2002) Adult
and subadult bull trout are largely piscivorous. Their food preferences include whitefish,
smelt, sculpins, eggs drifting following redd construction, sandlance, and salmonids.
(USFWS 2004)
Bull trout have both resident and migratory life cycles. Resident forms complete their life
cycles in or near the tributary where they were born and reared. Migratory bull trout
spawn in tributary streams and rear as juveniles for 1 to 4 years before migrating to either
a lake (adfluvial), river (fluvial), or salt water (anadromous) where they mature (USFWS
1999b).
CHINOOK SALMON
Chinook salmon have a variable life history. On the basis of the season during which the
adults return to their home streams to spawn, they are classified as spring, summer or fall
races. All races spawn in the fall, with spring runs spawning first and summer and fall
races following in succession. Generally, spring Chinook select the upper reaches of
tributaries, summer Chinook use the mouths of tributaries, and fall Chinook use the
mainstem of larger streams (Wydowski and Whitney 2003).
Optimal water temperature for juvenile spring Chinook salmon is 54 to 55°F while optimal
water temperature for fall Chinook salmon is approximately 59 to 64°F. In freshwater and
initially in saltwater young Chinook feed upon small invertebrates, though after out-
migrating to saltwater they convert to a diet of fish rather quickly (Wydoski and Whitney
2003).
STEELHEAD
Steelhead, the anadromous form of rainbow trout, commence life in streams and migrate
to seawater as smolts. Most steel head in Washington become smolts at Age 2. Out-
migration occurs during April through June, with a peak about mid-April. Most maturing
steelhead ascend spawning streams from December to February (winter-run). In some
streams there is a smaller summer-run in August and September (Wydoski and Whitney
2003).
Western Washington Steelhead are present in lakes of most drainages of Puget Sound,
coastal streams and the lower Columbia River (Wydoski and Whitney 2003). Steelhead
generally prefer fast water in small-to-large mainstem rivers, and medium-to-large
tributaries. In streams with steep gradient and large substrate, they spawn between these
steep areas, where the water is flatter and the substrate is small enough to dig into. The
steeper areas make excellent rearing habitat for the juveniles (WDFW 1999). Many
steelhead do not die after spawning, unlike the pattern in Pacific Salmon.
Steel heads are capable of surviving in a wide range of temperature conditions from 32 to
80°F but prefer water less than 70°F, containing high amount of dissolved oxygen, at least
7 ppm. They aggressively defend feeding territories in streams where typical forage
consists of drift organisms and aquatic vegetation (Reese and Harvey 2001 ). Juvenile
steelhead feed primarily on foods that are drifting on the surface, in the water column, or
along the bottom of streams or lakes; aquatic insects, amphipods, aquatic worms, and fish
eggs. Occasionally they eat small fish. Steelhead may feed at any time throughout a 24-
hour period but usually feed most actively around dusk. (NatureServe Explorer, 2006)
References
NatureServe. . 2006. An online encyclopedia of life. Version 4.6. NatureServe, Arlington,
Virginia. Accessed April 20, 2007.
http://www.natureserve.org/explorer/servlet/NatureServe?searchName=ONCORH
YNCHUS+MYKISS+
Reese, Carl D. and Brett C. Harvey. 2001. Temperature-Dependent Interactions
between Juvenile Steelhead and Sacramento Pikeminnow in Laboratory Streams.
U.S. Forest Service, Pacific Southwest Research Station. Accessed April 25,
2007. http://www. fs. fed.us/psw/publications/harvey/cdr02a. pdf
Shellberg, Jeffery. 2002. Bull trout in Western Washington. January. The Water Center:
University of Washington. Accessed April 25, 2007.
http:! /de pts. wash i ngton. ed u/cwws/Outreach/F actSheets/bu lltrout. pdf
USFWS (United States Fish and Wildlife Service). 1999. ETWP; Determination of
Threatened Status for Bull Trout in the Conterminous United States. November 1.
Federal Register 64 (210): 31740.
____ 2004. Draft Recovery Plan for the Coastal-Puget Sound Distinct Population
Segment of Bull Trout (Sa/velinus confluentus). Volume I (of II): Puget Sound
Management Unit. Portland, Oregon. 389 + xvii.
WDFW (Washington Department of Fish and Wildlife). 1999. Salmon Facts: An
informational guide to our states national treasure. Accessed October 16, 2006.
http://wdfw.wa.gov/outreach/fishing/salmon.htm
Wydoski, RS., and RR Whitney. 2003. Inland Fishes of Washington. University of
Washington Press. Seattle.
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Appendix C: Sediment Characterization
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Summary of Chemical and Conventional Analytical Results
The following tables provide summaries of the chemical and conventional analytical
results of samples collected from the Dredged Materials Management Unit (DMMU)
Seaplane Base sample sites as compared to those criteria provided by the Regional
Sediment Evaluation Team (RSET) in the Northwest Regional Sediment Evaluation
Framework (SEF). See the attached figure for locations of DMMUs.
Table E-1. Conventional Parameters
WestDMMU East DMMU
11114/2006 1112712006
Parameter Value Q Units Value Q Units
Conventional
N-Ammonia 96.1 mg-69.5 mg-
Nlkg Nlkg
Sulfide 1.40 u mg/kg 1.48 u mg/kg
Total Organic Carbon 1.66 % 2.06 %
Total Solids 63.0 % 78.7 %
Preserved Total Solids 71.3 % 75.2 %
Total Volatile Solids 4.51 % 3.15 %
Grain Size
Gravel 0.5 % 5.0 %
Very Coarse Sand 0.9 % 4.7 %
Coarse Sand 2.1 % 14.0 %
Medium Sand 19.4 % 43.7 %
Fine Sand 35.0 % 22.4 %
Very Fine Sand 21.1 % 5.8 %
Coarse Silt 7.6 % 1.0 %
Medium Silt 4.6 % 1.0 %
Fine Silt 2.8 % 0.8 %
Very Fine Silt 1.5 % 0.7 %
8-9 Phi Clay 1.5 % 0.4 %
9-10 Phi Clay 0.8 % 0.2 %
<10 Phi Clay 2.2 % 0.2 %
Total Fines 21.0 % 4.3 %
NOTES
Q = Qualifier
U = Indicates that the target analyte was not detected at he reported concentration
Total Fines = Sum of all silt and clay fractions
West East
DMMU DMMU
SL1 SL2 11/14/06 11/27/06
Parameter (dry weight} (dry weight) Units Value Q Value Q
METALS
Antimony mg/kg 8 6
Arsenic 20 51 mg/kg 8 u 6 u
Cadmium 1.1 1.5 mg/kg 0.3 u 0.2 u
Chromium 95 100 mg/kg 27.8 21.4
Copper 80 830 mg/kg 27.1 19.7
Lead 340 430 mg/kg 8 2 u
Mercury 0.28 0.75 mg/kg 0.07 u 0.05 u
Nickel 60 70 mg/kg 29 24
Selenium mg/kg 0.3 u 0.2 u
Silver 2.0 2.5 mg/kg 0.5 u 0.4 u
Zinc 130 400 mg/kg 60.9 48.1
ORGANICS
Total LPAH 6,600 9,200 ug/kg 55 17 J
Naphthalene 500 1,300 ug/kg 20 u 20 u
Acenaphthylene 470 640 ug/kg 20 u 20 u
Acenaphthene 1,100 1,300 ug/kg 20 u 20 u
Fluorene 1,000 3,000 ug/kg 20 u 20 u
Phenanthrene 6,100 7,600 ug/kg 55 17 J
Anthracene 1,200 1,600 ug/kg 20 u 20 u
2-Methylnaphthalene 470 560 ug/kg 20 u 20 u
Total HPAH 31,000 55,000 ug/kg 458 92
Fluoranthene 11,000 15,000 ug/kg 110 29
Pyrene 8,800 16,000 ug/kg 80 30
Benz(a)anthracene 4,300 5,800 ug/kg 36 11 J
Chrysene 5,900 6,400 ug/kg 56 11 J
Benzofluoranthenes (b+k) 600 4,000 ug/kg 91 20 u
Benzo(a)pyrene 3,300 4,800 ug/kg 40 11 J
lndeno(1,2,3-c,d)pyrene 4,100 5,300 ug/kg 21 20 u
Dibenz(a,h)anthracene 800 840 ug/kg 20 u 20 u
Benzo(g,h,i)perylene 4,000 5,200 ug/kg 24 20 u
CHLORINATED HYDROCARBONS
1 , 3-Dichlorobenzene ug/kg 20 u 20 u
1,4-Dichlorobenzene ug/kg 20 u 20 u
1,2-Dichlorobenzene ug/kg 20 u 20 u
1,2,4-T richlorobenzene ug/kg 20 u 20 u
Hexachlorobenzene (HCB) ug/kg 20 u 20 u
West East
Parameter SL BT Units DMMU Q DMMU Q
Value Value
PHTHALATES-7
Dimethyl phthalate 46 440 ug/kg 20 u 20 u
Diethyl phthalate ug/kg 20 u 20 u
Di-n-butyl phthalate ug/kg 20 u 20 u
Butyl benzyl phthalate 260 370 ug/kg 20 u 20 u
Bis(2-ethylhexyl) phthalate 220 320 ug/kg 200 B 20 u
Di-n-octyl phthalate 26 45 ug/kg 20 u 20 u
PHENOLS
Phenol ug/kg 20 u 20 u
2-Methylphenol uglkg 20 u 20 u
4-Methylphenol uglkg 39 20 u
2,4-Dimethylphenol ug/kg 20 u 20 u
Pentachlorophenol ug/kg 99 u 97 u
MISCELLANEOUS EXTRACTABLE$
Benzyl alcohol ug/kg 20 u 20 u
Benzoic acid ug/kg 200 u 200 u
Dibenzofuran 400 440 ug/kg 20 u 20 u
Hexachloroethane ug/kg 20 u 20 u
Hexachlorobutadiene ug/kg 20 u 20 u
N-Nitrosodiphenylamine ug/kg 20 u 20 u
PESTICIDES
Total DDT 50 ug/kg 2.0 u 1.9 u
4,4'-DDD ug/kg 2.0 u 1.9 u
4,4'-DDE ug/kg 2.0 u 1.9 u
4,4'-DDT ug/kg 2.0 u 1.9 u
Aldrin ug/kg 0.98 u 0.97 u
Chlordane 37 ug/kg 0.98 u 0.97 u
Dieldrin ug/kg 2.0 u 1.9 u
Heptachlor ug/kg 6.4 y 10 y
gamma-BHC (Lindane) ug/kg 0.98 u 0.97 u
Total PCBs 60 120 ug/kg 29 y 16 u
B= Analyte detected in an associated Method Blank at a concentration greater than one-half of ARl's Reporting
Limit or 5% of the regulatory limit of %5 of the analyte concentration in the sample
J = Estminated concentration when the value is less that Ari's established reporting limits
Q= Qualifier
SL= Screening limit
U= Indicates that the target analyte was not detected at the reported concentration.
Y= The analyte reporting limit is raised to a positive chromatographic interference. The compound is not
detected at or above the raised limit but may be present below the limit.
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Appendix D: Pathways and Indicators Matrix
Parameters
., '' : 1\ • ·, -' )
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Water Quality
Temperature
Temperatures in Lake Washington frequently exceed the state water quality standard of
64°F (18°C) during the summer months (King County 2010). Monthly water quality
sampling indicated exceedances in mid-July and mid-August from 2003 through 2008.
These high temperatures may impair salmonid migration activities in the vicinity of the
Seaplane Base site and the migratory corridor to Puget Sound. Using the matrix of
pathways and indicators criteria, the baseline condition for temperature is not properly
functioning. The project is anticipated to maintain baseline conditions for temperature.
Sediment
Sedimentation/turbidity within the aquatic portion of the action area is at risk. Turbidity
generally ranges from 1-4 NTUs in this area. However, turbidity has been known to reach
approximately 50 NTUs during flood events, as it receives high sediment loads from the
Cedar River (King County 2010, NRA 2010). This sediment from the Cedar River delta
along the Seaplane Base is silty sand. The proposed project may degrade
sedimentation/turbidity over the short-term as the removal of dredged materials and
vibratory pile extraction/installation may temporarily increase sedimentation/turbidity within
the aquatic portion of the action area. However, this impact is not expected to exceed the
water quality standards set forth in the 401 permit from the DOE. Over the long-term the
project will maintain baseline conditions for sedimentation/turbidity.
Chemical Contamination and Nutrients
Within the aquatic portion of the action area chemical contamination is "properly
functioning". Within the project area, Lake Washington is a Category 2 water for fecal
coliform and a Category 1 water for total phosphorus; however, at this time it is not a
designated reach on the 303(d) list and contaminant concentrations in the sediment to be
dredged do not exceed sediment management criteria. During dredging activities the
disturbance of sediments may result in the release of contaminants from sediment pore
water and sediment particles. These resuspended chemical contaminants may be
adsorbed to resuspended particles, may partition to the water column or may be released
into the air possibly temporarily degrading chemical contaminants in the area. As the
sediment to be dredged from the Seaplane Base site does not have contaminants
exceeding sediment management standards set by RSET, any such resuspension is
f-, 1;", •• j
anticipated to be de minimus. Therefore, the proposed project is anticipated to maintain
baseline conditions over the long-term.
Habitat Access
Physical Barriers
There are currently no physical barriers to fish passage within the aquatic portion of the
action area in Lake Washington. Therefore the aquatic portion of the action area is
properly functioning in that respect. The proposed project is expected to maintain
baseline conditions as no physical barriers will be introduced as part of the project.
Habitat Elements
Substrate Embeddedness
Substrate within the aquatic portion of the action area is determined to be not properly
functioning. Substrate within the aquatic portion of the action area consists of
predominantly sand and silt with little gravel. Substrate is; therefore, determined to be
>30 percent embedded. The proposed project is expected to maintain baseline
conditions.
Large Woody Debris
The current LWD baseline condition is al risk based on the matrix of pathways and
indicators criteria. Existing land use of the shoreline has eliminated the potential LWD
recruitment at the site. However, Seaplane Base maintenance continually adds drifting
woody debris to the shoreline. The proposed project is expected to maintain baseline
conditions.
Refugia
The aquatic portion of the action area has an existing shallow shoreline lined with
concrete rubble and/or sheetpile substrate that does not provide refugia for juvenile
Chinook and water temperatures typically exceed criteria to support rearing during
summer months. Refugia is; therefore, at risk. The proposed project is expected to
maintain baseline conditions.
Channel Condition and Dynamics
Floodplain Connectivity
Floodplain Connectivity within the aquatic portion of the action area is not properly
functioning as has eliminated much the natural floodplain connectivity within the area.
The proposed project is expected to maintain baseline conditions.
Flow Hydrology
Increase in Drainage Network
The drainage network within the aquatic portion of the action area is at risk as human
disturbance has reduced natural channel lengths of streams. The proposed project is
expected to maintain baseline conditions.
Watershed Location
Road Density and Location
The road density within the Puget Sound Basin is calculated to be approximately 2 -3
miles of road per square mile of watershed and is; therefore, classified as at risk
(Fredenberg et al. 2005). The proposed project is expected to maintain baseline
conditions.
Disturbance Regime
Substantial disturbance of habitat within the action area has occurred due to extensive
development. Within the main basin of Puget Sound approximately 70% of the drainage
area is forested, 23% is urbanized, and 4% is used for agriculture (NMFS 2011 ).
The disturbance regime is; therefore, not properly functioning as over 15 % of the area is
developed (has been clear cut). The proposed project is expected to maintain baseline
conditions.
Riparian Reserves
Riparian areas within the action area are highly disturbed. It is estimated that 52% of the
shoreline in this area has been modified by human activities (NMFS 2011 ). Riparian
reserves in the main basin of Puget Sound are, therefore, not properly functioning. The
proposed project is expected to maintain baseline conditions.
References
Fredenberg et. al. (Fredenberg, Wade, Jeff Chan and John Young). 2005. Bull Trout
Core Area Conservation Status Assessment. U.S. Fish and Wildlife Service.
April. Accessed December 31, 2010.
htto://www.fws.gov/oacific/bulltrout/Maos/Statusmaos.html
King County. 2010. Major Lakes Monitoring. King County Water and Land Resource
Division. Last revised May 11. Accessed January 11, 2011.
htto://green.kingcounty.qov/lakes/LakeWashington.asox
NRA (Nueces River Authority). 2010. Instantaneous Field Measurements. November 23.
Accessed January 11, 2011.
www.nueces-ra.org/CP/CRP/SWQM/docs/soarameters.doc
NMFS (National Oceanic & Atmospheric Administration, National Marine Fisheries
Service). 2011. Environmental History and Features of Puget Sound. Northwest
Fisheries Science Center.
http://www. nwfsc. noaa. gov /ou bl i cations/tech memos/tm44/e nvironment. him
f
Appendix E: Noise Analysis
This page intentionally left blank for printing purposes.
'; 'F-'· ;_,_: t ti:,:
The following calculations and values are based on information and guidance from
Section 7: Noise Impact Assessment in the Biological Assessment Preparation Advanced
Training Manual for Transportation Projects, Version 02-2010; prepared by the
Washington State Department of Transportation; available online at:
http://www.wsdot.wa.gov/Environment/Biology/BA/default.htm#TraininqManual
Terrestrial Noise Attenuation (Seaplane Base, soft site):
For terrestrial animals sound is measures in dBA, or A-weighted, this deemphasizes the
upper and lower portions of the frequency spectrum, while emphasizing the middle portion
of the spectrum (where humans have the greatest sensitivity).
Construction Noise: 101 dB(A), Equipment which will generate construction noise within
the project area consists of a crane (81), bulldozers (82), excavator (81), dump trucks
(76), front loaders (79) and a vibratory pile ex1ractor (101 ).
Line source, soft site: -7 .5 dB(A)
Traffic noise: 55 dBA16
, Perimeter Road West runs adjacent to the project area
accommodating airport traffic and visitors to the park. Occasional seaplanes and airplanes
also contribute to the background noise within the project area.
Table 1: Noise Attenuation Table (for vibratory pile extraction)
Distance from source Vibratory Pile Extractor Traffic Noise
(feet) Point Source(-6), Soft site (-1.5) dB) Line Source(-3), Soft site (-1.5) dB)
50 101 55
100 93.5 50.5
200 86 46
400 78.5 41.5
800 71 37
1,600 63.5 32.5
12,800 41 19
25,600 33.5 14.5
51,200 26 10
16 City of Renton. 2007. Renton Municipal Airport Noise Study: Aircraft Noise 101/Study Scoping Meeting. September 25.
At what point will construction noise during pile installation attenuate to traffic noise over
soft ground:
Noise level: 55 dBA (Traffic Noise)
D = Do* 1 o((Construction Noise-Traffic Noise in dBA)/a))
D = 50 * 1 o((101-55)1101
D = 50 * 10(461101
D = 50 * 10(461
D = 50 * 39810_71706
D = 1,990,535.853 feet
Therefore at approximately 1,990,535.853 ft (377.05 miles), noise from vibratory pile
driving activities would attenuate to traffic levels_
As the project area is within an urban development it is anticipated that traffic noise is
representative of background noise levels within the area. Vibratory pile driving noise will
attenuate to background levels of 55 dBA prior to attenuating to traffic noise.
D = Do* 1 Q((Construction Noise-Ambient Noise in dBA)/a))
D = 50 * 10 (1101-55J12s1
D = 50 * 101•61251
D = 50 * 10!1841
D = 50 * 69_ 18309709
D = 3459.15 feet
Therefore at approximately 3459.15 ft (0.66 miles), noise from vibratory pile driving
activities would attenuate to ambient levels.
D = Do* 1 Q((Construction Noise-Ambient Noise in dBA)/a))
D = 50 * 10((06-55¥251
D = 50 * 10(s11251
D = 50 * 10!1-241
D = 50 * 17.37800829
D = 868.90 feet
Therefore at approximately 868.90 ft (0.16 miles), noise from general construction
activities would attenuate to ambient levels.
-' ,~ ..
Aquatic Noise Attenuation (Lake Washington) Seaplane Base:
Underwater noise is most commonly measured as instantaneous peak sound pressure level
dB(peakl or as the Root Mean Square dB 1RMS) pressure level during an impulse. The peak
pressure is the instantaneous maximum overpressure or underpressure observed during
each pulse and can be presented in Pascals (Pa) or SPL in decibels (dB) referenced to a
pressure of 1 micropascal (dB re: 1 µPa). The RMS level is the square root of the energy
divided by the impulse duration. This level is the mean square pressure level of the pulse.
It is used by NMFS to describe disturbance-related effects to aquatic organisms from
underwater impulse-type noises. When evaluating potential injury impacts to fish, peak
sound pressure (dBPEAt<l is often used (WSDOT 2010a).
Vibratory Pile Driving Construction Noise:
A 171 PEAK or 155 dBRMs" sound level is generally estimated 10 meters from a 12-inch
diameter steel pipe piles driven/extracted with a vibratory hammer.
Ambient noise:
A 150eEAK or 135 dBRMs" sound level is estimated
Practical Spreading Loss Model
The Practical Spreading Loss Model is used to determine the extent of project-related
underwater noise.
TL = 15Log(R1/R 2)
R 1 is the distance where noise attenuates to ambient levels and/or disturbance/injury
threshold levels
R2 is the distance from the source of the initial sound measurement
TL is the amount of spreading loss or the difference between the source sound level and
the ambient sound level at some distance
The distance to where the source sound level attenuates to background noise may be
calculated by rearranging the terms.
R 1 = R2*1 o(rn,si
"CalTrans. 2007. Compendium of Pile Driving Sound Data. September 27.
"WSDOT. 2010. Chapter 7 Construction Noise Impact Assessment. February. WSDOT Biological Assessment Preparation
Advanced Training Manual for Transportation Projects Manual. Page 7.34
This formula can then be used to determine the where construction noise will attenuate to
background noise.
R 1 = R2*10 1rn15J
R1 = R2•1 oH155-135Jt15J
R1 = 10*10l133l
R1 = 10*25.11886432
R1 = 215.28 meters
0.13 miles or 706 feet
Construction noise from vibratory pile driving activities will reach ambient levels
approximately 0.13 miles from pile driving activities.
The disturbance threshold for fish is 150dBRMs
R1 = R2*10{1u 15}
R1 = R2*10((155.15oy15)
R1 = 10•10 (033333333)
R1 = 10*2.15443469
R1 = 21.54 meters
0.01 miles or 71 feet
Construction noise from the vibratory pile extraction/installation will therefore disturb fish
within approximately 0.01 miles of pile driving activities.
WILL ROGERS-WILEY POST MEMORIAL SEAPLANE
BASE MAINTENANCE DREDGING
LAKE STUDY
RENTON, WA
TAX PARCEL NUMBERS: 0723059007, 0723059096, 1180000285 and 1180008400
PREPARED FOR:
BEN DAHLE
CITY OF RENTON AIRPORT
616 WEST PERIMETER ROAD, UNIT A
RENTON, WASHINGTON 98057
PREPARED BY:
GRETTE AsSOCIATES LLc
2102 NORTH 30TH' SUITE A
TACOMA, WASHINGTON 98403
(253) 573-9300
~. Grette Associates'tc V ENVIRONMENTAL CONSULTANTS
TABLE OF CONTENTS
I INTRODUCTION ................................................................................................................... 1
2 PROJECT SUMMARY ........................................................................................................... 1
3 LAKE ASSESSMENT NARRATIVE .................................................................................... 1
3.1 Lake Classification ........................................................................................................... I
3.2 Vegetative cover ............................................................................................................... I
3.3 Existing Ecological functions and project impacts .......................................................... 2
3.4 Observed fish and wildlife use and project impacts ......................................................... 3
3 .5 Vegetation/Tree Protection .............................................................................................. 3
3 .6 No Net Loss .................................................................................................. , ................... 3
4 LAKE STUDY SUPPLEMENTAL INFORMATION .......................................................... .4
4.1 Analysis of Alternatives ................................................................................................... 4
4.2 Impact Evaluation ............................................................................................................ 5
5 MITIGATION .......................................................................................................................... 5
6 REFERENCES ........................................................................................................................ 6
1 INTRODUCTION
The City of Renton Airport and Seaplane Base has contracted with Grette AssociatesLLC to
generate a Lake Study pursuant to the requirements specified in RMC Section 4-8-1200 for the
purposes of submitting for a Shoreline Exemption to conduct a maintenance dredge. The parcels
within which maintenance dredge activities will occur, identified as King County tax parcels
0723059007, 0723059096, 1180000285 and I 180008400, are within the northeast and northwest
quarter section of Section 7, Township 23 North, Range 5 East, WM and are located primarily
within the City of Renton in King County, WA.
2 PROJECT SUMMARY
The purpose of the maintenance dredging is to alleviate operational problems caused by
sediment filling the existing Seaplane Base Approach Channel and Mooring Basin that has
occurred during previous major storm events such as those occurring in November 2006 and
January 2009. The proposed maintenance dredging will remove recent sediment deposits from
under the floating docks and up to the edge of existing structures to restore the Seaplane Base
access and mooring basin to required depths for safe operations. Refer to Sheet 2 of 3. The
proposed maintenance dredge depths are based on historical dredging areas and Federal Aviation
Administration design standards for seaplane operations. A total estimated volume of 16,000
cubic yards of dredged material will be removed from a 76,000 square foot area within the
facility. The dredged sediment will be disposed of at the Elliot Bay Open Water disposal site.
3 LAKE ASSESSMENT NARRATIVE
3.1 Lake Classification
The proposed maintenance dredge project will occur in an aquatic overlay district adjacent to a
shoreline high intensity overlay district.
3.2 Vegetative cover
The proposed maintenance dredge project will occur within Lake Washington. Aquatic plants
commonly found within Lake Washington include hornwort, pondweeds, and the invasive
Eurasian water milfoil and fragrant water lily. However, vegetation within the project area and
surrounding area is minimal. The proposed dredge is not anticipated to adversely impact aquatic
plants within Lake Washington.
The vegetation within the upland area adjacent to the proposed maintenance dredge project,
including I 00 feet on either side of the property boundaries, includes ornamental trees and
shrubs and maintained lawn areas. The project does not include upland work, but may include
the utilization of upland portions of the airport property for the storage of equipment. If
Will Rogers-Wiley Post Memorial Seaplane Base
Maintenance Dredging
Lake Study 1 January 2013
equipment storage does occur upland, it will be stored in areas that are currently gravel, asphalt,
or some other form of impervious surface and will not impact upland vegetation.
3.3 Existing Ecological functions and project impacts
The existing ecological functions and processes of the site are described in detail with the
Biological Assessment (City of Renton 2012) and are summarized in Table I as provided below.
Table 1: Pathway and indicator matrix for Lake Washington within the aquatic action
area*
ENVIRONMENT AL BASELINE EFFECTS OF THE ACTIONS
PATHWAYS: Properly Not Properly Restore I INDICATORS At Maintain Degrade Functioning Risk Functioning Enhance
W~ref~µiiiity: ; ;'"· . . . . . '·-·,Jc'.,'"''" <·,.. • .-. . .... ' . . .. . . ~·. --· . . . : < . -i .
Temperature X X
X X
Sediment/ Turbidity X (long-(short-
term) term)
X X
Chemical Contaminants/ X (long-(short-Nutrients term) term)
Habitat'A®ess .·· •'
.. >:.,,-','' ·.•.
: . "'''' .
.··, ·-:· ' .. ·:i'::C\,(' .. :··.· .. ,. ... .
Physical Barriers X X
Habitat E1emen&~ . . .. ·>: ,, :·: . ... · .. : .. . . .• --,
Substrate Embeddedness X X in Rearing Areas
Large Woody Debris X X
Refugia X X
ChrumeJC6nilition'&nvnimlics ,. .. · · '.;,: • <: . .'{·--· .': ~--<-,-'[, . -~:,,·t~··r·~,.<,:.; ·;,_·_-:,,>_, ·<: __
. '·,.-, .. ._,
Floodplain Connectivity X X
F1ow'Hvilii:liowf'2i;, >_::·.-:.·· .. · ·:: _. ··.,-,· , ... ·•.· .. ,,· ·.·<; '\'•· , .. , •s.c:i_·_'
' : ' ·' _·,, ,.·: ' ' .
Increase in Drainage X X Network
v,ralershea•.cqiilfitions' • :,;: · . , ''.>··· f • :: .• ., . , · :: · ; ' ;, : ' ... .• s::;· ... ·;:.--..·-:·:·· .•,.,:;. <t~_-:· ·"-'';.' . ' '·. ·.-."-.-·:_·_.
Road Density and X X Location
Disturbance Regime X X
Riparian Reserves X X
* This summary table was originally provided as Table 2 within the Biological Assessment (City
of Renton 2012).
As shown in this table, the proposed maintenance dredge project is anticipated to maintain existing
function but may have short term impacts to turbidity as a result of the dredge process. The dredge
Will Rogers-Wiley Post Memorial Seaplane Base
Afaintenance Dredging
Lake Study 2 January 20 I 3
material has been determined to be clean and suitable for open water disposal and as such any impacts
from chemical contaminates and/or nutrients as a result of this dredge process are exceedingly unlikely
even on a short term basis. For further analysis of existing ecological functions and anticipated
project impacts, refer to the Biological Assessment (City of Renton 2012).
3.4 Observed fish and wildlife use and project impacts
The observed fish and wildlife use of the site are described m detail with the Biological
Assessment (City of Renton 2012). Table 2 below summarizes results of the Biological
Assessment review and includes a list of project relevant Endangered Species Act listed species
and designated critical habitat within the action area as well as the project effect determination.
Table 2: ESA species and Project Effect Determination Summary
Soecies
Coastal-Puget Sound DPS* of Bull Trout
(Salvelinus confluentus)
Bull Trout Critical Habitat
Puget Sound ESU** of Chinook Salmon
( Oncorhynchus tshawytscha)
Chinook Salmon Critical Habitat
Puget Sound DPS* of Steelhead Trout
(Oncorhynchus mykiss)
*D1stmct populat10n segment
**Evolutionarily significant unit
Effect Determination
May Affect, Not Likely to Adversely
Affect
May Affect, Not Likely to Adversely
Affect
May Affect, Not Likely to Adversely
Affect
May Affect, Not Likely to Adversely
Affect
May Affect, Not Likely to Adversely
Affect
Overall, project impacts to endangered fish species will be accomplished by conducting work
during approved USACE in-water work windows designated during the permit process,
anticipated to be (July 16 through July 31 and November 16 through December 31). For further
analysis of the observed fish and wildlife use and project impacts, refer to the Biological
Assessment (City of Renton 2012).
3.5 Vegetation/Tree Protection
As noted in Section 3.2, this project will be conducted within Lake Washington and will not
impact any upland trees or vegetation and is not anticipated to adversely impact aquatic
vegetation.
3.6 No Net Loss
Pursuant to RMC 4-3-090(0)(2) and RCW 90.58.020, shoreline projects must demonstrate that
they are "carried out in a manner that prevents or mitigates adverse impacts to ensure no net loss
Will Rogers-Wiley Post Memorial Seaplane Base
A..faintenance Dredging
lake Study 3 January 2013
of ecological functions and processes in all development and use. Permitted uses are designed
and conducted to minimize, in so far as practical, any resultant damage to the ecology and
environment"
This project has been designed to restore existing historical use and remove sediment that was deposited
as a result of two flood disasters. Although the project will result in temporary increases to turbidity as a
result of the dredge process (Refer to Section 3.3 and the attached Biological Assessment), overall the
project will have no long term effects on shoreline ecologic functions such as fish and wildlife habitat,
food chain support, and water temperature maintenance. In addition the project will have no long
term effect on shoreline processes including but not limited to, water flow; erosion and accretion;
sediment delivery, transport, and storage; large woody debris recruitment; organic matter input;
and nutrient and pathogen removal. For further analysis, refer to the Biological Assessment (City
of Renton 2012).
4 LAKE STUDY SUPPLEMENTAL INFORMATION
4.1 Analysis of Alternatives
Shoreline project may impact shoreline function. As such, it is prudent to analyze a proposal to
determine if an alternative exists that may be less impactful than the project as proposed. RMC
4-8-120 identifies specific alternatives that must be addressed as part of this analysis. The
remainder of this section identifies the five required alternatives, bulleted and in italics, and
directly followed by project relevant justification of that alternative:
• Avoid any disturbances to the stream, lake or buffer by not taking a certain action, or by
moving the action.
The proposed maintenance dredge is located within the boundaries of the functioning City of
Renton Airport and Seaplane Base and is being conducted to restore a previously existing
navigable channel and as such cannot be located elsewhere. The Seaplane Base is already
experiencing reduced functionality as a result of the sediment deposited by the 2006 and 2009
flood events. If the proposed maintenance dredge is not conducted continued sediment
deposition resulting from future flood events is likely to continue to limit and eventually prevent
future Seaplane base operations.
• Minimize any stream, lake or buffer impacts by limiting the degree or magnitude of the
action and its implementation by using appropriate technology and engineering, or by taking
affirmative steps to avoid or reduce the impacts.
The proposed maintenance dredge has been designed to limit the degree and magnitude of the
project by focusing on restoring existing historical function of the previously existing navigation
Will Rogers-Wiley Post Memorial Seaplane Base
Maintenance Dredging
Lake Study 4 January 2013
channel. The proposed maintenance dredge does not serve to increase the area utilized by the
Seaplane Base use or modify the location of the previously existing use.
• Rectifying the impacts by repairing, rehabilitating, or restoring the affected area.
The proposed maintenance dredge is not anticipated to have any long term impacts. Refer to
Section 3.3. The temporary impacts associated with the dredge activity, such as increased
turbidity, are anticipated to be temporary and highly localized.
• Reducing or eliminating the adverse impact over time by preservation and maintenance
operations over the life of the action
The proposed maintenance dredge is not anticipated to have any long term adverse impacts.
• Compensate for any stream, lake, or buffer impacts by replacing, enhancing, or providing
similar substitute resources or environments and monitoring the impact and taking
appropriate corrective measures.
The proposed maintenance dredge is not anticipated to have any long term adverse impacts.
Short term impacts that may occur during maintenance dredge activities, such as temporary
increases in water turbidity, will be monitored to ensure that state and federal water quality
standards are not exceeded.
4.2 Impact Evaluation
The functional values of the project site are described both in Section 3.3 of this document and
within the Biological Assessment (City of Renton 2012). The proposed maintenance dredge is
likely to maintain all existing functions at their current level and is not anticipated to have any
long term impacts. The project has been limited in design to restoring historic land use function
and complying with current federal aviation requirements. If maintenance dredging is not
conducted, use of the Seaplane Base will continue to be limited until the accrued sediment
prevents seaplanes from utilizing the Renton seaplane base. This project is not anticipated to
have any significant detrimental impacts to the project area or the watershed system.
5 MITIGATION
The proposed maintenance dredge project is not anticipated to impact shoreline processes or
result in net loss of shoreline function. As such, mitigation is not proposed for this project.
Will Rogers-Wiley Post Memorial Seaplane Base
1faintenance Dredging
Lake Study 5 January 2013
6 REFERENCES
City of Renton, 2012. Will Rogers-Wiley Post Memorial Seaplane Base: Biological Assessment.
SITE PLAN
0 100 200
SCALE IN FE ET
DA TUM: CORPS OF ENGINEERS LOCK OA TUM
CITY OF RENTON EBQPQSEC!· MAINTENANCE DREDG ING
SEAPLANE BASE MAINTENANCE UP TO 16,000 CY I COAST & HARBOR IN: LAKE WASH INGTON ENGINEE RI NG DREDGING PROJECT CITY Of RENTON 110 MAIN SlREET, SUITE 103 AI:..
ED MONDS, WA 98 020
LAKE STUDY SITE MAP .c.o.u.till'.;_ K ING PH 4 2 5 -778 -2542
APPLICATION BY: CI TY Of RENTON SHEET 3 Of 3 OAIL 1/3/13