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HomeMy WebLinkAboutRS_Northwest_Architectural_Lake_Study_20102 i LAKE STUDY FOR Asdourian Remodel 3901 Lake Washington Boulevard N City of Renton, WA Wetland Resources, Inc. Project #20102 Prepared By Wetland Resources, Inc. 9505 19th Avenue SE, Suite 106 Everett, WA 98208 (425) 337-3174 Prepared For Northwest Architectural LLC Attn: Bruce Sinkey 19705 SW 65th Ave Tualatin, OR 97062 October 27, 2020 Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC October 22, 2020 ii TABLE OF CONTENTS 1.0 PROPOSED PROJECT ...................................................................................................................1 1.1 PROJECT LOCATION ...........................................................................................................................1 1.2 LANDSCAPE SETTING ..........................................................................................................................1 1.3 SITE DESCRIPTION ..............................................................................................................................2 1.4 PROJECT DESCRIPTION ......................................................................................................................4 2.0 LAKE STUDY ...............................................................................................................................4 2.1 ASSESSMENT METHODOLOGY ...........................................................................................................4 WITHIN LAKE WASHINGTON, THE FOLLOWING SPECIES ARE DEPICTED: .......................................5 3.0 SHORELINE MITIGATION PLAN (LAKE STUDY, SUPPLEMENTAL) ..............................................6 3.1 ALTERNATIVES ANALYSIS ...................................................................................................................6 3.2 IMPACT EVALUATION .........................................................................................................................7 4.0 SHORELINE MITIGATION PLAN .................................................................................................7 5.0 USE OF THIS REPORT ..............................................................................................................11 6.0 REFERENCES ............................................................................................................................12 Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC October 22, 2020 iii (this page intentionally left blank) Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 1 1.0 PROPOSED PROJECT 1.1 PROJECT LOCATION The project occurs on King County Tax Parcel 3342700070. This is a .31-acre parcel, located at 3901 Lake Washington Boulevard North in the City of Renton. Access to the property is from the east via Lake Washington Boulevard North. The Public Land Survey System Locator is Section 32, Township 24N, Range 5E, WM. Site-Scale Vicinity Map 1.2 LANDSCAPE SETTING Basin: Puget Sound Sub-Basin: Water Resource Inventory Area (WRIA) 8 – Cedar River/Renton River Watershed: Lake Washington Watershed Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 2 Landscape-Scale Vicinity Map (Google Earth) The study area is located on the east shore of Lake Washington, 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. 1.3 SITE DESCRIPTION The subject property is immediately surrounded to the north and south by residential development, to the east by Lake Washington Boulevard North and to the west and North by Lake Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 3 Washington. An existing house, driveway, and deck cover the majority of the property. Between the house and the shoreline of the lake, the backyard is covered entirely by a large deck. Two small vegetated areas are located on the site, including a maple tree on the northern side of the house and ivy under the deck, adjacent to the ordinary high water mark. Existing development along the lake’s shoreline is limited to the existing rock bulkhead deck and dock. The face of the bulkhead clearly defines the ordinary high water mark (OHWM) of Lake Washington. No vegetation is present waterward of the OHWM and no aquatic vegetation or lake-fringe wetlands were observed. Beach substrate consists of sorted sand and large cobble pieces on a moderate grade. This is consistent with a high-energy shoreline. No other habitat features were observed on or in the vicinity of the subject property. Bing Maps Bird’s Eye View Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 4 1.4 PROJECT DESCRIPTION The applicant proposes to add additional elevation to the dwelling story entirely within the boundary of the existing impervious surfaces. There will be no increase in impervious surfaces or impact as a result of this development proposal. The footprint of the first and second floor of the structure will not be changed and will be no closer to the shoreline. The additional height will be partially within the required 25-foot setback, but not beyond the footprint of the first-floor. All existing overwater structures (dock) will remain. Given no vegetation removal will occur, impervious surfaces will not increase and improvements will be behind (landward) of the existing primary structure first floor footprint, no net loss of shoreline ecological function will occur. The City of Renton’s Shoreline Master Program (SMP) requires applicants proposing shoreline modifications on existing legal lots to provide a Stream or Lake Study that meets the requirements of RMC 4-8-120D.19. 2.0 LAKE STUDY 2.1 ASSESSMENT METHODOLOGY 2.1.1 Field Investigation Principal Ecologist, Scott Brainard, PWS, conducted a site investigation on May 18, 2020. 2.1.2 Limit of Study The proposed project occurs on tax parcel (tax ID number 334270070). Lack of legal access to adjacent parcels prevents Wetland Resources, Inc. (WRI) staff from performing detailed investigation in surrounding areas. Therefore, this investigation involved a site visit to the subject property and evaluation of existing on-line information, include the USFWS National Wetlands Inventory (NWI), USDA/NRCS Web Soil Survey, WDFW SalmonScape Interactive Map, WDFW Priority Habitat and Species (PHS) Interactive Map, and King County iMap. 2.1.3 Lake Assessment Narrative Lake Washington, a Type S water, is the only aquatic critical area located on and near the subject property. With the exception of minor landscaping and ivy under the existing deck, the subject property lacks significant native vegetation. Generally, the surface area of the site is dominated by existing impervious surfaces including the house and driveway 2.1.4 Ecological Functions The rock bulkhead deflects wave energy, which can cause erosion that leads to deeper water along the shoreline. High-energy/deepwater shorelines do not provide refuge opportunities for migrating fish. Bulkheads also prevent the establishment of riparian vegetation, which provides cover and forage opportunities for juvenile salmon. The absence of overhanging vegetation limits the ecological value for migrating fish. The existing impervious surface also limits the establishment of native vegetation, reducing the overall ecological value of this shoreline. Due to the mostly high-energy shoreline, lack of riparian vegetation, and the presence of impervious surface within the 25-foot setback, shoreline ecological functions are limited within the subject property. Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 5 Fish and Wildlife No fish or wildlife species were directly observed at the time of investigation. The Washington Department of Fish and Wildlife (WDFW), Pacific States Marine Fisheries Commission (PSMFC), and the Washington Dept. of Natural Resources (WADNR) are the primary agencies that provide publicly available information used for making fish presence determinations consistent with the water typing rules set forth in WAC 222-16-030. The following information 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 species are depicted: • fall Chinook (documented presence), • coho (documented presence), • winter steelhead (documented presence), • sockeye salmon (documented presence), • bull trout (documented rearing), • kokanee (documented presence) PSMFC StreamNet Map Tool StreamNet is a fish distribution database maintained by the PSMFC as a regional clearinghouse for fish data. In the vicinity of the project area, fish presence is only depicted within Lake Washington. StreamNet states the presence of the following species: • fall Chinook (migration only) • coho (migration only) • sockeye salmon (migration only) • winter steelhead (migration only) • bull trout (migration only) WDNR Forest Practices Activity Mapping Tool (FPAMT) FPAMT is an online GIS database that aids the process of submitting a Forest Practices permit application. The tool is useful for the purposes of this study because WDNR models fish presence. FPAMT depicts Lake Washington as a fish-bearing shoreline of the state. No other features are noted in the vicinity of the project. WDFW Priority Habitat and Species (PHS) Maps No terrestrial priority habitats are listed on or near the site. Aquatic priority habitats for the above- listed species are noted on the PHS maps. Measures to Protect Trees No tree removal will occur as part of this development proposal. Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 6 No Net Loss of Shoreline Ecological Function The existing development along the shoreline provides limited ecological value due to its developed and maintained condition. Given the location of the improvement, construction is not expected to cause any temporary or permanent impacts to the existing ecological function of the lake. Given the lack of shoreline function currently provided by the existing lot and ecologically isolated location of the improvement, no net loss of shoreline ecological function is expected. 3.0 SHORELINE MITIGATION PLAN (LAKE STUDY, SUPPLEMENTAL) The applicant is proposing to maintain the footprint of the existing impervious surfaces and not increase the degree of impact. Therefore, no mitigation is proposed as part of this project. However, in order to address the footprint increase of the proposed third story, native shrubs and ground cover will be added on the north side of the existing SFR adjacent to the significant tree. A total of approximately 200 square feet will be planted in this area. SMC 25.06.020(1) requires that mitigation for environmental impacts be applied in the following order. The applicant’s response immediately follows each sequencing principle (as indented, italicized text). 3.1 ALTERNATIVES ANALYSIS Avoidance Avoiding the impact altogether by not taking a certain action or parts of an action; The applicant is proposing to remodel the existing house in a location that is no closer to the lake than the existing first floor of the primary structure. This work will be entirely constructed over the top of existing impervious surface and will not involve removing any vegetation, or temporary or permanent impacts to natural buffer or setback areas. This is the only feasible location for the improvement since it involves building over the existing structure on a small waterfront lot. Minimization Minimizing impacts by limiting the degree or magnitude of the action and its implementation by using appropriate technology or by taking affirmative steps to avoid or reduce impacts; Impact minimization will be achieved in the following ways: • The house has been designed to be built over the existing footprint of the existing impervious surfaces and will be no closer to the lake; • BMPs will be implemented and the existing structure will minimize the potential for sedimentation to the lake; and • Materials selection does not include wood treated with toxic compounds. Rectification Rectifying the impact by repairing, rehabilitating, or restoring the affected environment; The affected environment in this case is the buffer zone that is entirely covered with impervious surfaces. Rectification is not practical for this project because repair, rehabilitation, and restoration could only be achieved by, for example, removing the existing house. No opportunities for rectification are known to exist for this project. Reduction Reducing or eliminating the impact over time by preservation and maintenance; The proposed structure will be regularly maintained and preserved by the Homeowner, to reduce the frequency Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 7 of short-term impacts associated with repair/replacement actions. Compensation Compensating for the impact by replacing, enhancing, or providing substitute resources or environment; Approximately 200 square feet of mitigation is proposed on the north side of the house in the vicinity of the existing significant tree. No increase in impervious surfaces or impact will occur from this proposed development activity 3.2 IMPACT EVALUATION (a) Identification, by characteristics and quantity, of the resources (stream, lake) and corresponding functional values found on the site; Lake Washington, a Type S water is the only critical area located on the site. Given the existing developed nature of the subject property, the ecological function provided by the on-site buffer is limited (refer to the ecological function section of this report). (b) Evaluation of alternative locations, design modifications, or alternative methods of development to determine which option(s) reduce(s) the impacts on the identified resource(s) and functional values of the site; Given that this is a narrow waterfront single-family lot, alternative locations for the proposed remodel are not feasible. If the proposed addition location were modified, it’s likely that the overall impervious surfaces and impact would be similar. (c) Determination of the alternative that best meets the applicable approval criteria and identify significant detrimental impacts that are unavoidable; Given that virtually the entirety of the site is currently developed and covered with impervious surfaces, no detrimental impacts will occur from this proposal. (d) Evaluation of the cumulative impacts on the system, to the extent that the site resources and functional values are part of a larger natural system such as a watershed; No cumulative impacts will occur from this project, as there will be no net loss of shoreline ecological function. (e) Evaluation, for shorelines regulated by RMC 4-3-090, of how the preferred alternative achieves the standard of no net loss of ecological functions under RMC 4-3-090D2; No net loss of shoreline ecologist function will occur as part of this proposal. (f) Evaluation of each of the mitigation plan criteria found in RMC 4-3-050L1, Mitigation Plan Required. Approximately 200 square feet of mitigation is proposed on the north side of the property between the existing structure and the OHWM. Section 4.0 Shoreline Buffer Mitigation Plan below meets the criteria established in RMC 4-3-050L1. 4.0 SHORELINE MITIGATION PLAN The applicant proposes to offset potential impacts associated with increasing the building height by 9.8 feet by removing a 4-foot strip of sidewalk and installing native vegetation along the north side of the parcel between the existing house and OHMW. The proposal is expected to slightly improve shoreline ecological function by removing impervious surfaces, adding native vegetation, Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 8 and increasing structural diversity between the northern part of the existing structure and OHWM. Design, specifications, and location of the proposed plantings are depicted on attached Lake Study and Shoreline Mitigation Plan Map. Shoreline Enhancement Planting Plan Common Name Latin Name Size Quantity Oregon grape Mahonia nervosa 1 gallon 3 Flowering currant Ribes sanguineum 1 gallon 3 Mountain spirea Spiraea splendens 1 gallon 2 Idaho fescue Festuca idahoensis 1 gallon 15 Tufted hair grass Dechampsia cespitosa 1 gallon 15 Kinnikinnik Arctostaphylos uva-ursi 1 gallon 15 Sword fern Polystichum munitum 1 gallon 10 PROJECT MONITORING PROGRAM Requirements for monitoring project: 1. Initial compliance/as-built report 2. Semi-annual site inspection (in the spring and in the fall) for years 1-3 3. Annual site inspection (in the spring) for years 4-5 3. Annual reports including final report (one report submitted in the fall of each monitored year) Purpose for Monitoring The purpose for monitoring this mitigation project shall be to evaluate its success. Success will be determined if monitoring shows at the end of five years that the definitions of success stated below are being met. The property owners shall grant access to the mitigation area for inspection and maintenance to the contracted landscape and/or wetland specialist and the City of Renton during the period of the bond or until the project is evaluated as successful. Monitoring Methodology During the as-built site visit, representative photo points shall be selected. Photos shall be taken from the same location during each monitoring year to establish a record of plant growth throughout the monitoring period. The exact location of permanent photo points shall be depicted in the as-built report, and Year 0 photographs shall be included in the as-built letter. Vegetation sampling shall be conducted as a qualitative assessment, for the purpose of establishing approximate invasive cover and installed species cover. Total invasive cover will be determined as follows: the contracted biologist will record approximate invasive species coverage within the planting area. Total observed invasive species cover will be divided by the total enhancement area, yielding approximate invasive cover. The findings will be presented in each annual report. Total observed native species cover will be divided by the total enhancement area, yielding approximate areal coverage. The findings will also be presented in each annual report. Conducting a rough qualitative assessment of invasive species cover and installed plant cover is an adequate reporting measure given the small total planting area. Each monitoring report will establish an approximate percent coverage of invasive species, which will serve as the basis for maintenance recommendations. Maintenance shall occur following any monitoring report documenting an increase in invasive species cover, even if cover is reported below ten percent. Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 9 Report Contents Annual monitoring reports shall be submitted by October 31 of each year during the monitoring period. As applicable, monitoring reports must include descriptions / data for: 1. Site plan and vicinity map 2. Historic description of project, including date of installation, current year of monitoring, restatement of mitigation / restoration goals, and performance standards 3. Plant survival and areal coverage for every plant community, 4. Monitoring methodology in the context of assessing performance standards, 5. Assessment of nuisance / exotic biota and recommendations for management 6. Color photographs taken from permanent photo-points PROJECT SUCCESS AND COMPLIANCE Upon completion of the proposed mitigation project, an inspection by a qualified biologist will be made to document the correct mitigation installation. A compliance letter will be supplied to the City of Renton for review, within 30 days after the completion of planting. City review and acceptance of the as-built letter is required prior to commencement of the 5-year monitoring period. A landscape professional or wetland biologist will perform monitoring of the plantings annually in the spring and fall for the first three years, and in the fall only for years four and five. A written report describing the monitoring results will be submitted to the City of Renton after the fall site inspection of each monitored year. Final inspection will occur five years after completion of this project. The contracted consultant will prepare a final report describing the project in the context of success standards. If the project does not meet the below Definitions of Success in year five, additional years of monitoring will occur until the project is considered successful. The bond will not be released until a final monitoring report is submitted that deems the project successful. City of Renton Contact Certain actions within the wetland and buffer mitigation areas may require inspection or approval by City of Renton staff. Requests for inspection/approval shall be coordinated with the City. Definition of Success Performance standards have been established to assess the success of the mitigation project. Performance standards are as follows: Year 1 Monitoring Success Standard: 100 percent survival of installed woody species No greater than 15 percent coverage of invasive species Year 3 Monitoring Success Standard: 90 percent survival of installed species No greater than 15 percent coverage of invasive species New growth of woody plants shall be observable and documented Year 5 Monitoring Success Standard: 80 percent survival of installed woody species Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 10 No greater than 10 percent coverage of invasive species New growth of woody plants shall be observable and documented Maintenance This mitigation project will require periodic maintenance to replace mortality of installed species. Maintenance is also necessary to control invasive, non-native plant species, and competing grasses. The planting areas will be maintained in the spring of each year for the five-year monitoring period, and in the fall if recommended by the contracted biologist. Maintenance will include hand removal of competing grasses and non-native vegetation from a 2-foot diameter ring surrounding a given plant. Removal of invasive species shall be done by hand to decrease the likelihood of damage occurring to the plantings. All blackberry, reed canarygrass, and other aggressive invasive species sprouting anywhere within ten feet of the planting area shall be removed during each maintenance period. Herbicide use is prohibited. Following each monitoring site visit, recommendations will be made for the replacement of plant mortality and other general maintenance. All maintenance recommendations related to invasive cover shall be addressed within 45 days of the date written on the annual report requiring action, and the City shall be supplied with a letter documenting how these recommendations were addressed. If necessary, re-planting shall occur in the fall, and a brief memo will be drafted and submitted to the City of Renton indicating that re-planting has successfully occurred. Contingency Plan If, during any of the inspections, more than 20 percent of woody plants are severely stressed, or it appears more than 20 percent may not survive, additional plantings of the same species or, if necessary, alternative species may be added to the planting area. If this situation persists into the next inspection, a meeting with a representative for the City of Renton, the consulting wetland biologist, and the property owner will be scheduled to decide upon contingency plans. Elements of the contingency plan may include, but will not be limited to more aggressive weed control, plant mortality replacement, species substitution, fertilization, and/or soil amendments. PERFORMANCE BONDING A performance bond or other assurance device shall be provided to the City of Renton for the period of five years from the completion of the project, in the amount of 150% of the estimated cost for plant material and labor, maintenance, and monitoring. This bond shall be released at the end of five years, upon a successful determination by the City of Renton related to the above Definitions of Success. Total Estimated Project Cost * Plants and Labor $870 Mulch $ 48.75 Maintenance $ $1,000 (for five years) Monitoring $2,000 (for five years) Total Estimated Project Cost $3,918.75 *Total Estimated Project Cost calculated using amounts from the King County Bond Quantity Worksheet. Total Estimated Bond Amount (150% of Estimated Project Cost) $5,878.13 Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 11 5.0 USE OF THIS REPORT This Lake Study is supplied to Northwest Architectual LLC 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. Scott Brainard, PWS Principal Ecologist Asdourian Remodel Lake Study WRI Project #20102 Northwest Architectural LLC July 16, 2020 12 6.0 REFERENCES 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. http://www.pugetsoundnearshore.org/supporting_documents/WRIA_8_LFR_FINAL.pdf. Accessed December 2016. NOAA National Weather Service Forecast Office, Seattle, Washington. http://www.weather.gov/climate/index.php?wfo=sew. Accessed December 2016. Olson, P. and E. Stockdale. 2010. Determining the Ordinary High Water Mark on Streams in Washington State. Second Review Draft. Washington State Department of Ecology, Shorelands and Environmental Assistance Program. Lacey, WA. Ecology Publication # 08-06-001. StreamNet. 2016. StreamNet Mapper. http://www.streamnet.org/mapping_apps.cfm. Accessed December 2016. U.S. Fish and Wildlife Service. National Wetland Inventory (NWI). Wetlands Mapper. http://www.fws.gov/wetlands/. Accessed December 2016. Washington State Department of Fish and Wildlife (WDFW). 2016. Priority Habitats and Species: PHS on the Web. (http://wdfw.wa.gov/mapping/phs/). Accessed December 2016. Washington State Department of Fish and Wildlife (WDFW). 2016. SalmonScape. (http://wdfw.wa.gov/mapping/salmonscape/index.html). Accessed December 2016.