Loading...
resub1 BLD2023-0159+Stream Delineation Report+3.2.2023_7.20.14_AM+3396939S C I E N C E & D E S I G N WATERSHED COMPANY February 28, 2023 Derek and Kacie Janke 803 61h Avenue South Edmonds, WA 98020 206-380- 4021 Edmonds803@gmail.com RE: Janke Residence, Stream Delineation Report The Watershed Company Reference Number: 230226 Summary This report has been prepared to present the findings of a stream delineation study located at 803 6th Avenue South in the City of Edmonds (parcel #00610900001102). The information and findings presented in this report are in response to the City of Edmonds Critical Area Determination related to construction on the subject property in the vicinity of a critical area. The following documents are enclosed: • Site Photos • Delineation Sketch One stream, Stream A, is a Type F fish -bearing perennial stream in the southwest portion of the study area. The City of Edmonds requires a 100-foot standard buffer for Type F streams. Two wetlands, Wetlands A and B, were also observed in the south portion of the study area but not classified for this study. The wetlands and stream are disconnected from the project area by a paved driveway. The City of Edmonds does not regulate buffers interrupted by paved areas and therefore neither the stream nor wetland buffer extend into the project area. Table 1. Summary of wetlands, streams, and required buffers. Feature Name Category/Type Buffer (ft) Setback (ft) Stream A Type F 100 15 Wetland A - - 15 Wetland B - - 15 750 6th Street South I Kirkland, WA 98033 P425.822.5242 If 425.827.8136 1 watershedco.com Stream Delineation Report Janke, D. February 2023 Page 2 Study Area The study area is approximately 0.63 acres in size and is defined as the subject property (parcel #00610900001102) and the neighboring client -owned parcel to the south (parcel #00610900001103) (Figure 1). Adjacent public or private property within 200 feet was screened from the edge of the subject parcels or nearest publicly accessible land; no private property was accessed without permission. It is in Section 25 of Township 27 North, Range 03 East. f � f �f Puget Sound i wooaway r J I i I - •-•-•-•- - •-•-- t PiII'll :he,,ron�. r Pcin7P:rk wParkland { Park '� +•ti Snohomish County `525. � f MWAM '4+ Ed I 3 �srier � King County Figure 1. Vicinity map. The in -set shows the approximate study area outlined in yellow. Map source: PDS Map Portal. Stream Delineation Report Janke, D. February 2023 Page 3 Methods Field investigations for the delineation study were conducted on February 20, 2023 by The Watershed Company ecologist Anna Murphy. Characterization of weather conditions was determined using the WETS table methodology (USDA, NRCS 2015). The "Sand Point WFO" station from 1991-2020 was used as a source for precipitation data (http://agacis.rcc-acis.org/). The WETS table methodology uses climate data from the three months prior to the site visit month to determine if normal conditions are present in the study area region. The study area was evaluated for streams based on the presence or absence of an ordinary high water mark (OHWM) as defined by Section 404 of the Clean Water Act, the Washington Administrative Code (WAC) 220-660-030, and the Revised Code of Washington (RCW) 90.58.030 and guidance documents including Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State (Anderson 2016) and A Guide to Ordinary High Water Mark (OHWM) Delineation for Non -Perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States (Mersel and Lichvar 2014). Public -domain information on the subject properties was reviewed for this delineation study. Resources and review findings are presented in Table 2 of the "Environmental Setting" section of this letter. Environmental Setting The study area is in the Puget Sound sub -basin of the Cedar-Sammamish watershed (WRIA 8). It is in the Pine Park neighborhood in the City of Edmonds. Site topography gently slopes westward. The subject property is developed with a single-family residence, driveway, and deck. The work area is limited to the residence's front yard where vegetation has been cleared and a cement retaining wall has been installed (Photo 1). The client -owned parcel to the south contains two sheds, mulched parking areas for a boat trailer and cars, a chicken coop, a pond in the center portion, and a stream, Shellabarger Creek, in the southwest portion. The study area parcels are bordered to the east and south by single-family residences and to the west by 6f Avenue South. The subject property is bordered to the north by Hemlock Way. Puget Sound is located approximately one mile west of the study area. Stream Delineation Report Janke, D. February 2023 Page 4 Public -domain information reviewed for the site is summarized below (Table 2). Table 2. Summary of online mapping and inventory resources. Resource Summary USDA NRCS: Web Soil Survey Entire study area is mapped as Everett very gravelly sandy loam, 0 to 8 percent slopes, not a hydric soil. USFWS: NWI Wetland Mapper Shellabarger Creek is mapped as Riverine habitat (R4SBC) in the southwest portion of the study area WDFW: PHS on the Web No features mapped. Shellabarger Creek is mapped in the southwest portion of the study WDFW & NWIFC: Statewide Washington Integrated Fish area as gradient accessible to coho salmon Distribution WNHP Data Explorer No features mapped Shellabarger Creek mapped as a perennial Type F fish -bearing WA-DNR: Forest Practices Application Mapping Tool stream Shellabarger Creek is mapped as a Non -Fish Habitat Seasonal Snohomish County PDS Map Stream flowing northwesterly in the southwest portion of the study Portal area, eventually draining to Puget Sound approx. 0.8 miles west. Shellabarger Creek is mapped as gradient accessible to coho salmon. Portions of both parcels mapped as containing landslide and City of Edmonds map erosion hazard areas. Shellabarger Creek is mapped flowing northwesterly in the southwest portion of the study area. Zoned as RS-6. WETS Climatic Condition Wetter than normal Findings Wetlands Wetland A is a slope wetland observed in a terrace adjacent to the right bank of Stream A in the southwest portion of the study area (Photo 2). Wetland B is a ponded depressional wetland in the south portion of the study area (Photo 3). Streams The open channel of Stream A enters the south edge of the study area from under a footbridge on the neighboring property. Stream A flows northwesterly and exits the southwest edge of the Stream Delineation Report Janke, D. February 2023 Page 5 study area through an 18-inch caged cement culvert under 6"l Avenue S (Photo 4). According to the City of Edmonds GIS online map, Stream A flows west through a series of culverts, stormwater pipes, and open channels before discharging into Puget Sound approximately 0.8 miles west of the study area. Stream A has an average measured bankfull width of three feet and at the time of the site visit, an average measured wetted width of two feet. The evaluated segment lacks large woody material and contains one long riffle upstream of the culvert before cascading over large cobbles. The stream bed contains small patches of reed canary grass with a substrate of cobble, gravel, and sand. The gradient, as estimated via the City of Edmonds GIS map topography, is less than five percent within the study area. Overhanging vegetation is dominated by lady fern and reed canarygrass and riparian vegetation is dominated by red alder and pacific willow trees (Photo 6). Non -critical Areas Areas outside of observed wetlands do not meet the criteria for wetland hydrophytic vegetation, hydric soils, and/or wetland hydrology. Non -wetland and stream areas include the entire subject property and areas upslope of Wetlands A, B, and Stream A on the south parcel. The dominant vegetation includes a canopy of red alders and an understory of rhododendron, ornamental shrubs (such as hydrangea and rose), giant butterbur, and lawn (Photos 7-10). Local Regulations Critical areas in the City of Edmonds are regulated under Chapter 23, Natural Resources, of the Edmonds City Code and Community Development Code (ECDC). Streams According to the City of Edmonds Critical Areas Determination by City Planner Tristen Sewell (2/13/23), Shellabarger Creek is a known anadromous fish -bearing stream. During the site visit, the evaluated segment of Stream A met the criteria for containing fish habitat with a bankfull width of at least two feet and a gradient of less than 16%. The downstream reach of Stream A also appears to meet the criteria for containing fish habitat as measured by City of Edmonds GIS map topography. As stream flow is presumed perennial, Stream A is a Type F water. Streams are regulated as Fish and Wildlife Habitat Conservation Areas (FWHCAs) under EDCD 23.90.010 and classified using the criteria in WAC 222-16-030. Per EDCD 23.90.040(D)(1), Type F anadromous fish -bearing streams adjacent to reaches with anadromous fish access are prescribed a 100-foot buffer measured on each side of the stream from the OHWM. Stream Delineation Report Janke, D. February 2023 Page 6 Critical Area Buffer Interruption Per ECDC 23.40.220(C)(4), areas physically separated from a stream or wetland due to existing paved areas may be exempt from prescribed buffer widths if they are proven to be functionally isolated from the stream or wetland. The City of Edmonds requires documentation demonstrating that the interrupted buffer area is functionally isolated, considering the hydrologic, geologic, and/or biological habitat connection potential and the extent and permanence of the physical separation. The existing paved driveway on the subject property functionally disconnects the entire project area from Stream A and Wetlands A and B. The following sections demonstrate that the driveway prevents the project area from performing stream and wetland hydrologic and habitat buffer functions. Pre -construction and Existing Conditions The existing paved driveway (Photo 1) is approximately 13 feet wide and extends along most of the south boundary of the subject property. The driveway has been in place since at least 2007, according to Google Earth aerial imagery. The project area is adjacent to the driveway's north edge. Wetlands A and B and Stream A are approximately 45 feet south of the driveway. Prior to construction, the project area contained lawn, a paved pathway, a non-native hedge, planter beds made of creosote logs, with a creosote log tiered retaining wall bordering the north, south, and west edges (Photos 11 and 12). The area between the south edge of the driveway and the wetlands and stream is outside of the project area. This area contains mostly lawn, sporadic ornamental shrubs, and mulched areas for boat trailer and car parking (Photos 13 and 14). Hydrologic and Water Quality Functions The low density of vegetation, as well as the driveway's extensive impervious surface, results in a generally degraded buffer area providing low hydrologic and water quality functions. The project area is graded relatively flat with a slight slope towards the west. Water within the project area is expected to move generally west towards 61h Avenue S rather than south; water flowing south will be redirected west by the driveway away from the wetlands and stream. The areas of lawn and the impervious surface of the driveway provide poor hydrological function due to the lack of dense woody vegetation and vertical structure to infiltrate and uptake precipitation and surface water and slow runoff velocities. The project area also provides little flood storage, as it is in a relatively flat area upslope of Wetland A and Stream A (Photo 15). The position of the driveway adjacent to the project area isolates the project area from providing even a reduced hydrologic function to the wetlands and stream. Stream Delineation Report Janke, D. February 2023 Page 7 Wetland B is located southeast of the project area and at nearly the same elevation. The combination of the topography and the driveway disconnect any water in the project area from flowing southeast to Wetland B. The extensive presence of lawn and the lack of dense, native woody vegetation that can trap and store sediment and pollutants limit the project area's capacity to provide significant water quality functions. The driveway further reduces the project area's stormwater filtering, detention, and infiltration functions that would otherwise benefit the wetlands and stream. However, the removal of the creosote logs results in improved water quality by reducing a source of pollution from the area. Habitat Function Much of the existing on -site habitat is poorly suited for native wildlife. The pre -construction condition of the project area and the area south of the driveway contain degraded habitat with low vegetation density and structural diversity and a lack of native plants. No trees or groundcover were present in the project area or currently exist between the driveway and Wetland A and Stream A. Areas of lawn provide little habitat function as they contain a monoculture of species compared to an area with a diversity of native species. The scattering of non-native, ornamental shrubs have the potential to provide food and cover resources to local wildlife, but function poorly compared to native plant species, which native wildlife species have evolved to utilize. Pre -construction, the project area also contained landscaped beds, areas which are often heavily managed and limit habitat functions through regular disturbance and the removal of organic and woody material (i.e., leaves and branches). The footprint of the driveway reduces available habitat in an already degraded area, resulting in a low habitat connection potential between the wetlands and stream and the project area. Overall, the project area north of the existing driveway is physically separated from Stream A, Wetland A, and Wetland B by a legally established paved driveway. This physical interruption functionally isolates the project area, resulting in insignificant hydrologic and habitat functions. Therefore, pursuant to ECDC 23.40.220(C)(4), the project area is exempted from the prescribed wetland and stream buffer widths. Disclaimer The information contained in this letter is based on the application of technical guidelines currently accepted as the best available science and in conjunction with the manuals and criteria referenced above. All discussions, conclusions and recommendations reflect the best professional judgment of the author(s) and are based upon information available at the time the Stream Delineation Report Janke, D. February 2023 Page 8 study was conducted. All work was completed within the constraints of budget, scope, and timing. The findings of this report are subject to verification and agreement by the appropriate local, state and federal regulatory authorities. No other warranty, expressed or implied, is made. Please call if you have any questions or if we can provide you with any additional information. Sincerely, Anna Murphy Ecologist References Anderson, P.S. et al. 2016. Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State. (Publication #16-06-029). Olympia, WA: Shorelands and Environmental Assistance Program, Washington Department of Ecology. Mersel, M.K. and Lichvar, R.W. 2014. A Guide to Ordinary High Water Mark (OHWM) Delineation for Non -Perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States. ERDC/CRREL TR-14-13. Stream Delineation Report Janke, D. February 2023 Page 9 Site Photos Photo 1. View of retaining wall bordering the front yard adjacent to 6th Avenue S looking northwest. The paved driveway that interrupts the overlapping critical area buffers can be seen in the foreground. Stream Delineation Report Janke, D. February 2023 Page 10 Photo 2. View of Wetland A adjacent to the right bank of Stream A, looking east. Photo 3. View of Wetland B looking northeast. Stream Delineation Report Janke, D. February 2023 Page 11 Photo 4. View of Stream A entering a culvert under 6ch Avenue S. Photo 5. View of Stream A looking southeast. Stream Delineation Report Janke, D. February 2023 Page 12 Photo 6. Stream A riparian and overhanging vegetation. Stream Delineation Report Janke, D. February 2023 Page 13 Photo 7. View of northwest portion of client -owned south parcel looking west. Photo 8. View of eastern portion of the client -owned south parcel. Stream Delineation Report Janke, D. February 2023 Page 14 Photo 9. View of client -owned south parcel looking south. Photo 10. View the residence's back deck in eastern portion of subject property. Stream Delineation Report Janke, D. February 2023 Page 15 Photo 11. View of south edge of project area prior to construction (photo source: Kathryn Neumann) Photo 12. View of project area prior to construction looking south (photo source: Kathryn Neumann) Stream Delineation Report Janke, D. February 2023 Page 16 Photo 13. View of area south of the driveway looking west. Photo 14. View of area south of the driveway adjacent to Stream A and Wetland A and west of Wetland B. Stream Delineation Report Janke, D. February 2023 Page 17 Photo 15. View of elevation difference between Stream A and Wetland A and the driveway grade. The project area is out of view to the right. Wetland A is at the toe of the slope adjacent to Stream A. 2 THE WATERSHED COMPANY Stream Delineation Sketch — Janke Property Site Address: 803 6Ih Avenue S, Edmonds, WA Parcel Number: #00610900001102 and 00610900001103 Site Visit Date: February 20, 2023 ,4 HPm1n11, IAI. 750 Sixth Street South I Kirkland I WA 98033 p 425.822.5242 f 425.827.8136 Jurisdiction: City of Edmonds Prepared for: Derek Janke TWC Ref. No.: 230226 Note: Field sketch only. Features depicted are approximate and not to scale. Stream boundaries are marked with blue - and black -striped flags. All observations were made from within the study area; adjoining private properties were not entered. Page 1 of 1