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HomeMy WebLinkAboutAttachment_F_LakeStudy_ LAKE STUDY FOR 3007 MTN VIEW AVE N – DOCK REPAIR CITY OF RENTON Wetland Resources, Inc. Project #26011 Prepared By Wetland Resources, Inc. 9505 19th Avenue SE, Suite 106 Everett, WA 98208 (425) 337-3174 Prepared For Timothy Bovey 3007 Mountain View Ave N Renton, WA 98056 First Submittal: March 19, 2026 ATTACHMENT F Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 ii TABLE OF CONTENTS 1.0 INTRODUCTION ......................................................................................................................... 1 1.1 PROJECT LOCATION ........................................................................................................................... 1 1.2 LANDSCAPE SETTING .......................................................................................................................... 2 1.3 PROJECT DESCRIPTION ...................................................................................................................... 3 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 ..................................................................................................................... 4 2.4.1 Fish ............................................................................................................................................... 4 2.4.2 Amphibians and Reptiles ............................................................................................................. 4 2.4.3 Mammals ..................................................................................................................................... 5 2.4.4 Birds ............................................................................................................................................. 5 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 ............................................................................................................................. 7 2.6.3 Vegetation Removal .................................................................................................................... 7 2.6.4 Shading ........................................................................................................................................ 7 2.6.5 Forage Opportunities ................................................................................................................... 7 2.6.6 Pollution Sources .......................................................................................................................... 7 2.7 NO NET LOSS DISCUSSION ................................................................................................................ 8 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) ................................. 6 LIST OF APPENDICES APPENDIX A: LAKESIDE CONSTRUCTION SITE PLAN APPENDIX B: LAKE STUDY MAP Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 1 Lake Study WRI #26011 March 19, 2026 1.0 INTRODUCTION 1.1 PROJECT LOCATION The project occurs within a 0.65-acre property located at 3007 Mountain View Ave N (King County tax parcel 3342103930) 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) Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 2 Lake Study WRI #26011 March 19, 2026 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. - Landscape-Scale Overview Map (Image: King County, 2023) Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 3 Lake Study WRI #26011 March 19, 2026 1.3 PROJECT DESCRIPTION The proposed project is a residential dock repair. The project includes the following elements: • Install HDPE sleeves over 33 existing treated wood piles (includes one moorage pile) • 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. 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 on 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, south, and east by single-family residential development, and to the west by Lake Washington. The property is developed with an existing residence, semi-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. No trees or shrubs overhang the lake. See Figure 3 below. An existing 187-foot dock extends west from the bulkhead. The dock is 6.25 feet in width and is supported by 32 treated wood piles. The decking material is wood with no gaps, and the dock is relatively long to achieve sufficient depth to avoid propellor strike while mooring recreational watercraft. One moorage pile is located approximately 15 feet to the north of the dock. A boat lift and canopy are located on the south side of the dock. Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 4 Lake Study WRI #26011 March 19, 2026 Aquatic vegetation located waterward of the OHWM is limited to invasive species only (e.g. Eurasian milfoil). Riparian vegetation and lake-fringe wetlands are absent due to the rock bulkhead that spans several properties in either direction from the subject property. Lakebed substrate consists of fine sediment and cobble on a shallow 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- 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 WDFW 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. Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 5 Lake Study WRI #26011 March 19, 2026 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 No specific avian nesting, foraging, cover, or breeding habitat is present on or near the subject property due to lack of native vegetation (aquatic and terrestrial) and structural diversity. Although the study area 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. 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. The existing dock is constructed with 187 lineal feet of closed wooden decking. See Figure 3 below. 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. 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 sediment and through direct impacts to benthic communities that provide forage for juvenile salmon (Poston 2001). Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 6 Lake Study WRI #26011 March 19, 2026 - Rear Yard of Subject Property (Image: Applicant, 2026) 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. Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 7 Lake Study WRI #26011 March 19, 2026 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. 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. 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 1,133 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 33 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 Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 8 Lake Study WRI #26011 March 19, 2026 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. 3.0 USE OF THIS REPORT This Lake Study is supplied to Timothy Bovey 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 Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 3007 Mtn View Ave N - Dock Repair 9 Lake Study WRI #26011 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 Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 Appendix A Lakeside Construction Site Plan Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 VICINITY MAP NOT TO SCALE 0 40'80' 1"=40' 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 AS SHOWN ON ATTACHED PLANS. ALL WORK TO BE DONE IN EXISTING DOCK FOOTPRINT. PROPERTY OWNER: TIMOTHY BOVEY 3007 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 ROS AFN 20110223900005 AND KING COUNTY ASSESSOR'S GIS DATA. DOCK DIMENSIONS, PROJECT DESCRIPTION AND WATER DEPTHS PER LAKESIDE CONSTRUCTION. ORDINARY HIGH WATER (APPROX.) LEGAL DESCRIPTION: HILLMANS LK WN GARDEN OF EDEN # 1 LOT 2 RENTON LLA #LUA-10-063-LLA REC #20110223900005 SD LLA DAF- LOTS 64 & 65 SD BLK A TGW 2ND CL SH LDS BOVEY DOCK REPAIR 3007 MOUNTAIN VIEW AVE. N RENTON, WA 98056 2526 9/19/2025 3342103930 LAKESIDE CONSTRUCTION P.O. BOX 525 ISSAQUAH, WA 98027 (206) 850-0250 sales@lakesideseattle.com HOUSE #3007 LAKE WASHINGTON ±197' EXISTING DOCK ± 6 0 ' ±3 3 ' ±23 ' ±163' ±187' 10/8/2025 Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 SCALE: 1"=20' DOCK LAYOUT 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 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 NTS SCALE: 1"=20' DOCK PROFILE LAKE BOTTOM PROFILE (APPROX.) ORDINARY HIGH WATER (APPROX.) HDPE PIPE SLEEVE (AS NEEDED) EXISTING PILING PILE SLEEVING DETAIL NTS 3 4 "x24" GALV. THREADED ROD GASKET SEAL LAKEBED BOVEY DOCK REPAIR 3007 MOUNTAIN VIEW AVE. N RENTON, WA 98056 2526 9/19/2025 3342103930 2030 0' -10' 10' 10 040 -20' 0' -10' 10' -20' -55060708090100110120130140150160170180190 187.25' 6. 2 5 ' 10/8/2025 EXISTING BOAT LIFT W/CANOPY (NO WORK PROPOSED) = MOORAGE PILE (EXISTING) TO BE SLEEVED O Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 Appendix B Lake Study Map Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0 Docusign Envelope ID: C03B268B-2CA4-46E4-896A-A5FF9D02CFF0