HomeMy WebLinkAboutRS_LAKE_STUDY_
LAKE STUDY
FOR
2815 MTN VIEW AVE N – DOCK REPAIR
CITY OF RENTON
Wetland Resources, Inc. Project #26015
Prepared By
Wetland Resources, Inc.
9505 19th Avenue SE, Suite 106
Everett, WA 98208
(425) 337-3174
Prepared For
John Duggan
2815 Mtn View Ave N
Renton, WA 98056
First Submittal: March 19, 2026
ii
TABLE OF CONTENTS
1.0 INTRODUCTION ......................................................................................................................... 1
1.1 PROJECT LOCATION ........................................................................................................................... 1
1.2 LANDSCAPE SETTING .......................................................................................................................... 1
1.3 PROJECT DESCRIPTION ...................................................................................................................... 2
2.0 LAKE STUDY .............................................................................................................................. 3
2.1 LAKE CLASSIFICATION ....................................................................................................................... 3
2.2 LAKE ASSESSMENT METHODOLOGY ................................................................................................. 3
2.3 SITE DESCRIPTION .............................................................................................................................. 3
2.4 FISH AND WILDLIFE USE ..................................................................................................................... 3
2.4.1 Fish ............................................................................................................................................... 3
2.4.2 Amphibians and Reptiles ............................................................................................................. 4
2.4.3 Mammals ..................................................................................................................................... 4
2.4.4 Birds ............................................................................................................................................. 4
2.5 SITE-SCALE ECOLOGICAL FUNCTIONS – EXISTING CONDITIONS ................................................... 5
2.6 PROJECT IMPACT ANALYSIS ............................................................................................................... 6
2.6.1 Turbidity ...................................................................................................................................... 6
2.6.2 In-Water Noise ............................................................................................................................. 6
2.6.3 Vegetation Removal .................................................................................................................... 6
2.6.4 Shading ........................................................................................................................................ 7
2.6.5 Forage Opportunities ................................................................................................................... 7
2.6.6 Pollution Sources .......................................................................................................................... 7
2.7 NO NET LOSS DISCUSSION ................................................................................................................ 7
3.0 USE OF THIS REPORT ................................................................................................................ 8
4.0 REFERENCES .............................................................................................................................. 9
LIST OF FIGURES
– SITE-SCALE AERIAL OVERVIEW (IMAGE: COASTAL ATLAS, 2016) .............................. 1
- LANDSCAPE-SCALE OVERVIEW MAP (IMAGE: KING COUNTY, 2023) .......................... 2
- REAR YARD OF SUBJECT PROPERTY (IMAGE: APPLICANT, 2026) ................................. 5
LIST OF APPENDICES
APPENDIX A: LAKESIDE CONSTRUCTION SITE PLAN
APPENDIX B: LAKE STUDY MAP
2815 Mtn View Ave N - Dock Repair 1 Lake Study
WRI #26015 March 19, 2026
1.0 INTRODUCTION
1.1 PROJECT LOCATION
The project occurs within a 0.53-acre property located at 2815 Mountain View Ave N (King
County tax parcel 3342104010) in the city of Renton. Access to the property is from the east via
Mountain View Ave N.
– Site-Scale Aerial Overview (Image: Coastal Atlas, 2016)
1.2 LANDSCAPE SETTING
Basin: Puget Sound
Sub-Basin: East Lake Washington - Renton
Watershed: Water Resource Inventory Area (WRIA) 8 Lake Washington - Cedar - Sammamish
The study area is located on the east shore of Lake Washington at Coleman Point. Lake
Washington is the second-largest natural lake in Washington State with a total surface area of over
22,000 acres. The lake is approximately 20 miles in total length, with an average width of 1.5 miles
(Kerwin, 2001). Lake Washington is highly developed along much of the approximately 50 miles
of lake shoreline.
The subject property is located approximately 0.75 miles south of the confluence of Lake
Washington and May Creek, and approximately 1.25 miles north of the confluence with the Cedar
River. May Creek originates between Squak and Cougar Mountains and flows west through May
Valley before entering Lake Washington. The Cedar River drains the entire upper basin of Water
Resource Inventory Area (WRIA) 8.
2815 Mtn View Ave N - Dock Repair 2 Lake Study
WRI #26015 March 19, 2026
- Landscape-Scale Overview Map (Image: King County, 2023)
1.3 PROJECT DESCRIPTION
The proposed project is a residential dock repair. The project includes the following elements:
• Install HDPE sleeves over 12 existing treated wood piles
• Replace existing dock framing with ACZA-treated fir stringers and joists
• Replace existing closed wood decking with light-transparent (ThruFlow) decking
This project will not expand the footprint of the existing dock or require any new piles to be
installed in the lake. The applicant’s site plan is provided as Appendix A. Construction will occur
during one or two days within the state/federal work window to minimize impacts to juvenile
salmonids, and access will be from a small barge. No work or modifications will occur within the
terrestrial environment and therefore no measures to protect trees and vegetation are proposed.
The barge will be anchored to complete construction and will not be run aground.
2815 Mtn View Ave N - Dock Repair 3 Lake Study
WRI #26015 March 19, 2026
Due to the proposed waterbody alteration, the applicant has contracted Wetland Resources, Inc.
to prepare a Lake Study that meets the requirements of Renton Municipal Code (RMC) 4-8-
120.D.19 - Stream or Lake Study, Standard. This report and its appendices demonstrate compliance
with the Stream or Lake Assessment Narrative standards set forth in subsection c.
2.0 LAKE STUDY
2.1 LAKE CLASSIFICATION
Lake Washington is a Type S waterbody and is also recognized as a shoreline of statewide
significance because it exceeds 1,000 acres in total size.
2.2 LAKE ASSESSMENT METHODOLOGY
Existing habitat conditions on and near the subject property were determined from an in-office
review of recent site photos, Coastal Atlas oblique aerial photos, geo-referenced plan view aerials
from King County, and using publicly available natural resource information.
2.3 SITE DESCRIPTION
The subject property is located at the southern edge of Coleman Point, which is a depositional
feature created by alluvial drift originating from May Creek and the Cedar River. The subject
property is surrounded to the north and south by single-family residential development, and to the
west by Lake Washington. The property is developed with an existing residence and attached
garage, driveway, deck/patio, lawn, and ornamental landscaping.
The ordinary high water mark (OHWM) of Lake Washington is along the face of an existing rock
bulkhead. Sparse ornamental low shrub species are growing along the top of the bulkhead. One
mature non-native weeping willow overhangs the lake. See Figure 3 below. An existing 62-foot
dock extends west from the bulkhead. The dock is 6.25 feet in width and is supported by 12 treated
wood piles. The decking material is wood with no gaps, and skirting is present along the south and
west sides of the dock. A boat lift is located on the north side of the dock.
Aquatic vegetation located waterward of the OHWM is limited to a narrow zone of invasive species
(e.g. Eurasian milfoil) before the lake bottom exceeds maximum depth for aquatic vegetation.
Riparian vegetation and lake-fringe wetlands are absent due to the height of the property behind
the rock bulkhead, which spans several properties in either direction from the subject property.
Lakebed substrate consists of fine sediment and cobble on a moderate grade. On-site conditions
are consistent with a high-energy shoreline. No specific habitat features are known to be present
on or near the subject property.
2.4 FISH AND WILDLIFE USE
2.4.1 Fish
Fish species inhabiting Lake Washington include anadromous and non-anadromous salmonid
variants, and resident non-salmonids. Lake Washington provides a migratory corridor for adult
salmonids, rearing habitat for juveniles, and supports all life history stages for resident non-
2815 Mtn View Ave N - Dock Repair 4 Lake Study
WRI #26015 March 19, 2026
salmonids. The Washington Department of Fish and Wildlife (WDFW) is the primary agency that
documents fish species presence. The following represents the findings from each source.
WDFW SalmonScape Map Tool
SalmonScape is an online GIS database that contains publicly available resource information for
fish population studies and general species distribution (both documented and modeled presence).
Within Lake Washington, the following salmonid species are known to occur.
• fall Chinook (documented presence) • sockeye (documented presence)
• coho (documented presence) • bull trout (documented rearing)
• winter steelhead (documented presence) • kokanee (documented presence)
• rainbow trout (documented presence) • cutthroat trout (documented presence)
WDFW Fish Program – Warmwater Fish Survey
Based on a 2017 survey effort (WDFW 2017), the following non-salmonid warmwater and
coldwater species are known to occur in Lake Washington. They are listed in descending order of
abundance.
• threespine stickleback • northern pikeminnow • tench
• yellow perch • peamouth chub • common carp
• sculpin spp. • smallmouth bass • green sunfish
• pumpkinseed sunfish • bluegill • oriental weatherfish
• brown bullhead • largemouth bass • Salish sucker
• largescale sucker • black crappie • rock bass
2.4.2 Amphibians and Reptiles
Salamander, frog, toad, newt, turtle, and snake species are known to occur in the Lake Washington
basin, but none are expected to be present in abundance within the study area due to the absence
of wetland and riparian habitat along the lakeshore.
2.4.3 Mammals
The study area consists of managed vegetation communities in close proximity to residential
structures and is isolated from forested habitat corridors by suburban levels of development
between I-405 and the lake. No specific or valuable mammalian habitat is present on or near the
subject property. In consideration of the intensity of human land use, it is possible that squirrels,
mice, shrews, voles, rats, moles, raccoons, opossum, muskrats, and river otters could be present
along the lake shoreline. It is unlikely that larger mammals would be present.
2.4.4 Birds
Specific avian nesting, foraging, cover, or breeding habitat includes perching habitat in the
weeping willow near the lake. Habitat is generally lacking due to absence of native vegetation
(aquatic and terrestrial) and structural diversity. Although the study area mostly lacks avian habitat,
many species of landbird, raptor, shorebird, waterbird, and waterfowl are expected to be present
in the study area due to its landscape position along the shoreline of Lake Washington.
2815 Mtn View Ave N - Dock Repair 5 Lake Study
WRI #26015 March 19, 2026
2.5 SITE-SCALE ECOLOGICAL FUNCTIONS – EXISTING CONDITIONS
Ecological functions along the lakeshore are significantly impaired by human use. The bulkhead
increases nearshore erosion as incoming wave energy is refracted by a near-vertical wall of rock.
The bulkhead prevents natural sediment transport processes due to physical separation between
the aquatic and terrestrial environments. The bulkhead also prevents the establishment of riparian
vegetation that can provide cover and forage opportunities for fish and habitat for amphibians.
- Rear Yard of Subject Property (Image: Applicant, 2026)
The existing dock is constructed with 660 square feet of closed wooden decking. This type of
overwater structure creates high underwater light contrast by casting shade in ambient daylight
conditions, which impacts the aquatic food web as light availability for aquatic vegetation
photosynthesis is reduced. In this case, the impact is small because most of the dock’s area is beyond
the depth where aquatic vegetation is rooted.
High-contrast shading from overwater structures also increases predation risk for juvenile salmon
by altering migration patterns, distribution, and general behavior; fish that rely on vision and light
can become disoriented and subject to predation (Carrasquero 2001). Furthermore, the study area
is located near a predation bottleneck where cutthroat trout, yellow perch, rock bass, and black
crappie are known to consume large numbers of sockeye and Chinook fry as they enter the lake
from the mouth of the Cedar River (Tabor et al. 2024).
The existing piles and framing impair aquatic habitat because they are made of treated wood.
Treated wood piles and framing impact aquatic habitat by heavy metals accumulation in lake
2815 Mtn View Ave N - Dock Repair 6 Lake Study
WRI #26015 March 19, 2026
sediment and through direct impacts to benthic communities that provide forage for juvenile
salmon (Poston 2001).
2.6 PROJECT IMPACT ANALYSIS
Dock repair projects have the potential to impact aquatic habitat by increasing turbidity and in-
water noise, and by altering vegetation structure, shading, and forage habitat. The proposed
project will not alter terrestrial habitat, and therefore no impacts to amphibians, reptiles, mammals,
or birds are anticipated to occur. The project is not anticipated to negatively affect return-
migrating or resident adult salmonids because it will not alter their migration pathway or increase
predation risk. The project may affect non-salmonid fish species present in the lake, but these
impacts are not analyzed due to general population health/abundance trends.
Due to low population levels, this analysis focuses on impacts to juvenile salmonids, and discussion
is organized by impact type. In summary, the project has mostly discountable short-term negative
effects and a net positive effect due to the long-term benefit of replacing closed decking with light-
transparent decking.
2.6.1 Turbidity
Barge operation and pile sleeving will temporarily increase turbidity in the water column.
Turbidity can disrupt salmonid behavior and prey detection/reaction distances. Turbidity levels
associated with sleeving and boat operation are not expected to rise significantly beyond baseline
lake conditions, and nearby fish can easily avoid the impacted area during construction. For
example, propellor wash associated with recreational boating would be similar or more disruptive
to salmonid use of the lake.
Short-term turbidity impacts are trivial and do not merit compensatory mitigation.
2.6.2 In-Water Noise
Pile sleeving and barge operation will temporarily increase in-water noise levels during
construction. Project noise levels are not expected to measurably exceed baseline conditions
because impact drivers are not needed for sleeving. No impacts to juvenile fish are anticipated
because fish are adapted to relatively high ambient noise levels that regularly occur in streams and
freshwater systems.
Short-term in-water noise impacts are trivial and do not merit compensatory mitigation.
2.6.3 Vegetation Removal
Terrestrial vegetation removal is not necessary for access or materials transport because all work
will occur from a small barge. Temporary impacts to invasive aquatic vegetation in the nearshore
may result from barge operation and anchoring. The impact area is relatively small due to the
moderate grade, and invasive species will rapidly re-colonize the impact area if disturbed.
No measures to protect trees or vegetation are needed. Short-term aquatic vegetation impacts are
trivial and do not merit compensatory mitigation.
2815 Mtn View Ave N - Dock Repair 7 Lake Study
WRI #26015 March 19, 2026
2.6.4 Shading
As previously stated, closed wood decking creates shading and light contrast that can reduce forage
opportunities and increase predation risk for juvenile salmonids. Replacement decking (ThruFlow)
allows at least 42 percent light transmission, which meets WDFW standards for protection of fish
life. The existing dock creates 660 square feet of overwater shade. The proposed dock’s light-
penetrating grating will provide a significant reduction in high-contrast shade due to the relatively
large area of the existing dock.
Proposed decking represents a net benefit to aquatic habitat function that supports juvenile
salmonids. For this reason, the project is considered to be self-mitigating relative to the trivial short-
term impacts discussed in this section.
2.6.5 Forage Opportunities
Pile sleeving will eliminate some exposed wood that could be colonized by periphyton, algae, and
eventually benthic macroinvertebrates. The elimination of this vegetation would slightly reduce
forage opportunities for juvenile salmon but would also reduce predation as predator fish are
thought to hunt around piling structures because they provide a food source (Carrasquero 2001).
Long-term impacts to forage opportunities are trivial and do not merit compensatory mitigation.
2.6.6 Pollution Sources
Pile sleeving will modify 12 pollution-generating piles in the lake. This will reduce aquatic impacts
over time by slowing the leaching process from the existing treated wood piles into the water
column and lakebed substrate.
Existing dock framing was likely treated using ACQ or CCA and will be replaced with ACZA-
treated wood. Dock framing is not in continuous contact with water. Both treatments include
copper, arsenate, zinc, and chromate, which can be harmful to juvenile fish primarily via
consumption of contaminated prey. Due to the absence of continuous submersion, replacing the
framing is unlikely to cause any measurable harm to juvenile fish. Furthermore, replacing an
existing pollution-generating material with a pollution-generating material maintains the existing
condition and is not considered an impact.
Pile sleeving may slightly improve aquatic habitat function due to slowing the leaching effect of
submerged treated piles. Replacement of existing ACQ/CCA-treated wood decking with ACZA-
treated decking maintains the existing condition and does not merit compensatory mitigation.
2.7 NO NET LOSS DISCUSSION
RMC 4-3-090D.2.a.i requires applicants to ensure that development will not result in a net loss of
shoreline ecological functions or processes. All identified short-term effects related to construction
(i.e. turbidity, in-water noise, and vegetation removal) are trivial and do not merit compensatory
mitigation. Long-term effects (i.e. shading, forage opportunities, and pollution sources) are mostly
positive. Specifically, the removal of high-contrast shading and replacement with light-transparent
decking will improve aquatic habitat conditions for juvenile salmonids. Given the time-scale of
long-term impacts relative to short-term impacts, the benefits of the project easily offset the impacts
and ensure no net loss of shoreline ecological functions.
2815 Mtn View Ave N - Dock Repair 8 Lake Study
WRI #26015 March 19, 2026
3.0 USE OF THIS REPORT
This Lake Study is supplied to John Duggan as a means of determining the presence of critical
habitat, as required by the City of Renton during the permitting process. This report is based
largely on readily observable conditions and, to a lesser extent, on readily ascertainable conditions.
No attempt has been made to determine hidden or concealed conditions.
The laws applicable to salmonid habitat are subject to varying interpretations and may be changed
at any time by the courts or legislative bodies. This report is intended to provide information
deemed relevant in the applicant's attempt to comply with the laws now in effect.
The work for this report has conformed to the standard of care employed by ecologists. No other
representation or warranty is made concerning the work or this report and any implied
representation or warranty is disclaimed.
Wetland Resources, Inc.
Niels Pedersen
Senior Ecologist, PWS
2815 Mtn View Ave N - Dock Repair 9 Lake Study
WRI #26015 March 19, 2026
4.0 REFERENCES
Anderson et al. 2016. Determining the Ordinary High Water Mark for Shoreline Management Act Compliance
in Washington State. WA Department of Ecology. Publication #16-06-029.
Carrasquero, J. 2001. White Paper – Overwater Structures: Freshwater Issues. Herrera Environmental
Consultants. Accessed March 2026.
https://wdfw.wa.gov/sites/default/files/publications/00052/wdfw00052.pdf.
Kerwin, J. 2001. Salmon and Steelhead Habitat Limiting Factors Report for the Cedar – Renton Basin (Water
Resource Inventory Area 8). Washington Conservation Commission. Olympia, WA. Accessed
March 2026.
http://www.pugetsoundnearshore.org/supporting_documents/WRIA_8_LFR_FINAL.pdf
NOAA. 2026. National Weather Service Forecast Office, Seattle, Washington. Accessed March
2026. http://www.weather.gov/climate/index.php?wfo=sew
Poston, T. 2001. White Paper – Treated Wood Issues Associated with Overwater Structures in Marine and
Freshwater Environments. Battelle Memorial Institute. Accessed March 2026.
https://wdfw.wa.gov/sites/default/files/publications/00053/wdfw00053.pdf.
StreamNet. 2026. StreamNet Mapper. Accessed March 2026.
http://www.streamnet.org/mapping_apps.cfm
Tabor, R., L. Urgenson, M. Ramirez, A. Bosworth, K. Gordon. 2024. Synthesis Report: Predation
Impacts on Juvenile Chinook Salmon in the Lake Washington/Cedar River/Sammamish Watershed (WRIA
8). Prepared for the WRIA 8 Salmon Recovery Council. Accessed March 2026.
https://www.govlink.org/watersheds/8/pdf/WRIA8PredationSynthesisReport.pdf
U.S. Fish & Wildlife Service (USFWS). 2026. National Wetlands Inventory (NWI) Online Mapper.
Accessed March 2026. http://www.fws.gov/wetlands/Data/Mapper.html
Washington State Department of Fish and Wildlife (WDFW). 2017. Biological Assessment of the
Warmwater Fish Community in Lake Washington. WDFW Fish and Wildlife Fish Program.
Accessed March 2026.
https://wdfw.wa.gov/sites/default/files/publications/01944/wdfw01944.pdf
WDFW. 2026a. Priority Habitats and Species: PHS on the Web. Accessed March 2026.
http://wdfw.wa.gov/mapping/phs/
WDFW. 2026b. SalmonScape Online Mapping Application. Accessed March 2026.
http://apps.wdfw.wa.gov/salmonscape/map.html
Appendix A
Lakeside Construction Site Plan
VICINITY MAP
NOT TO SCALE
0 30'60'
1"=30'
ISSUE DATE:
PARCEL NUMBER:
PROJECT NUMBER:
1 OF 2
BY DESCRIPTIONREVDATE
PROJECT DESCRIPTION:
CONDUCT PERIODIC MAINTENANCE/REPAIR WORK
ON EXISTING RESIDENTIAL DOCK ON LAKE
WASHINGTON. DOCK FRAMING TO BE REPLACED
WITH ACZA TREATED FIR - STRINGERS TO BE
4" X 8", JOISTS/PILE CAPS TO BE 6" X 8".
WOODEN DECKING TO BE REPLACED WITH
THRUFLOW GRATED PANELS. PILES TO BE
SLEEVED WITH HDPE TUBES. ALL WORK TO BE
DONE IN EXISTING DOCK FOOTPRINT.
PROPERTY OWNER:
JOHN DUGGAN
2815 MOUNTAIN VIEW AVE. N
RENTON, WA 98056
CONTACT:
IRWIN LAND USE CONSULTING, LLC
P.O. BOX 1715
BELLINGHAM, WA 98227
(360) 410-6745
irwinlanduse@gmail.com
*LOT BOUNDARIES AND BUILDING LOCATIONS PER SURVEY AFN 8206019002 AND KING COUNTY ASSESSOR'S GIS DATA. DOCK DIMENSIONS, PROJECT DESCRIPTION AND WATER DEPTHS PER LAKESIDE CONSTRUCTION.
ORDINARY HIGH WATER LINE
(APPROX.)
EXISTING DOCK
LEGAL DESCRIPTION:
HILLMANS LK WN GARDEN OF EDEN # 1 POR OF LOTS & SH LDS ADJ
BEG NXN MDR LN WITH S LN OF SD 80 TH N 46 DEG 33 MIN 56 SEC
W 27.08 FT TO TPOB TH N 50 DEG 55 MIN 04 SEC E 36.07 FT TH N
65 DEG 50 MIN 45 SEC E 20 FT TO W MGN OF N P R/W TH NWLY
ALG SD R/W MGN 75.97 FT TH S 68 DEG 46 MIN 54 SEC W 20 FT TH
S 50 DEG 25 MIN 04 SEC W 67 FT M/L TO MDR LN TH S 50 DEG 25
MIN 04 SEC W 49.15 FT TH S 66 DEG 29 MIN 57 SEC W 215.58 FT TO
INNER HBR LN TH S 40 DEG 35 MIN 00 SEC E 80.82 FT TH N 63 DEG
38 MIN 40 SEC E 222.51 FT TH N 50 DEG 55 MIN 04 SEC E 47 FT
TO TPOB
DUGGAN
DOCK REPAIR
2815 MOUNTAIN VIEW AVE. N
RENTON, WA 98056
2529
10/21/2025
3342104010
LAKESIDE CONSTRUCTION
P.O. BOX 525
ISSAQUAH, WA 98027
(206) 850-0250
sales@lakesideseattle.com
HOUSE
#2815
LAKE WASHINGTON
MO
U
N
T
A
I
N
V
I
E
W
A
V
E
.
N
±10
7
'
±83
'
±7
6
'
±62
'
SCALE: 1"=10'
DOCK LAYOUT
ISSUE DATE:
PARCEL NUMBER:
PROJECT NUMBER:
2 OF 2
BY DESCRIPTIONREVDATE
LAKESIDE CONSTRUCTION
P.O. BOX 525
ISSAQUAH, WA 98027
(206) 850-0250
sales@lakesideseattle.com
SCALE: 1"=10'
DOCK PROFILE
LAKE BOTTOM PROFILE
(APPROX.)
ORDINARY HIGH WATER
(APPROX.)
PIER END SECTION
4"x8" STRINGER
(TYP)
PILE
(TYP)
(2) 2"X6"
CEDAR FASCIA
(ALL AROUND)
ALTERNATING
1
2
"x16" GALV. THRU-BOLTS
AND
1
4
"x12" EPOXY TIMBER LOCKS
NTS
HDPE PIPE SLEEVE
(AS NEEDED)
EXISTING
PILING
PILE SLEEVING DETAIL
NTS
3
4
"x24" GALV.
THREADED ROD
GASKET SEAL
LAKEBED
DUGGAN
DOCK REPAIR
2815 MOUNTAIN VIEW AVE. N
RENTON, WA 98056
2529
10/21/2025
3342104010
2030
-5'
0'
-10'
-15'
5'
10'
10 040
-20'
-5'
0'
-10'
-15'
5'
10'
-20'
-5506065
62.25'
25
.
2
5
'
14.25'
48.00'
19
.
0
0
'
6.
2
5
'
Appendix B
Lake Study Map