Loading...
21-101917-Wetland Delineation-07-21-2014-V1 July 21, 2014 Ed Kim Hotel Concepts, Inc. 2200 – 6th Ave., Ste 520 Seattle, WA 98121-1820 Via email: edkim@hotelconcepts.us Re: Steel Lake Stream and Wetland Delineation Review Study The Watershed Company Reference Number: 140508 Dear Ed, This letter summarizes the findings of the Wetland and Stream Delineation Review Study conducted at Steel Lake, 1931 South 304th Street in the City of Federal Way. Ecologist Ryan Kahlo, PWS, and I met Jason Walker (Perteet) and Matt Herrera (City of Federal Way) on-site July 2, 2014, to discuss discrepancies observed regarding the previous delineation study and to establish priorities for the re-delineation site visit. During the site visit, previously placed wetland boundary flags were checked for accuracy and the ordinary high water mark (OHWM) of Redondo Creek and Steel Lake were assessed. Changes to the prior stream and wetland boundaries are described below. The following attachments are included:  Wetland Delineation Map with revisions Methods Existing documents regarding the proposed project as well as the previously-delineated on-site wetland, Redondo Creek, and Steel Lake were reviewed for this study. Public- domain information was also reviewed. These sources include USDA Natural Resources Conservation Service Soil maps, U.S. Fish and Wildlife Service National Wetland Inventory maps, Washington Department of Fish and Wildlife interactive mapping programs (PHS on the Web and SalmonScape), Washington State Department of Natural Resources Forest Practices Activity Mapping Tool (FPARS), King County’s GIS mapping website (iMAP), and the City of Federal Way’s Shoreline Master Program Documents. The study area was evaluated for wetlands using methodology from the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region Version 2.0 (Regional Supplement) (US Army Corps of Engineers [Corps] May 2010) and Western Washington Wetland Rating System (Ecology, Steel Lake Stream and Wetland Delineation Review Study Ed Kim July 2014 Page 2 Aug 2004, revised 2006) (Rating System Guidance). The wetland boundary flags placed by Raedeke Associates, Inc., in October 2012 were re-evaluated. The wetland boundary was determined on the basis of an examination of vegetation, soils, and hydrology. Areas meeting the criteria set forth in the Regional Supplement were determined to be wetland. Soil, vegetation, and hydrologic parameters were sampled at several locations along the wetland boundary to make the determination. New wetland flags were placed where observable discrepancies in the original delineation were noted by TWC and Perteet. The distance and compass bearing from the location of the new flags to the location of the original flags were recorded in the field. This information was used to edit the original delineation figure to more accurately depict the wetland boundary (see Wetland Delineation Map). The OHWM of Redondo Creek and Steel Lake were determined based on the definition provided by the Washington Department of Fish and Wildlife and WAC 220-110- 020(69). The OHWM is located by examining the bed and bank physical characteristics and vegetation to ascertain the water elevation for mean annual floods. Areas meeting the definition were determined to be the OHWM. Findings Wetlands Upon evaluation of the 2012 Raedeke delineation, TWC and Perteet determined that the feature that was flagged as one large lake-shore wetland is two wetlands bisected by an area that is instead characterized as the OHWM of Steel Lake due to a break in hydrophytic vegetation. The Rating System Guidance for determining lake-shore wetland units says to “…separate the vegetated parts into different units at the points where the wetland vegetation thins out to less than a foot in width for at least 33ft (10m)” (see also Figure 1). All of the wetland vegetation associated with the two lake- shore wetlands is located at or below the OHWM of Steel Lake. The non-wetland area contains no vegetation below the OHWM; the substrate is composed of an unconsolidated gravel bed typical of the greater lake substrate. The topography in the non-wetland area is also distinct, dropping off immediately from upland to lake-waters. The break between wetland units occurs between flags 1-14 through 1-20. “Wetland A” occurs west of this break and continues north along Redondo Creek. “Wetland B” is located east of the vegetation break and continues off-site. Steel Lake Stream and Wetland Delineation Review Study Ed Kim July 2014 Page 3 Figure 1. Example of where to break a lake-shore wetland into multiple units from the Rating System Guidance. Wetland A contains scrub-shrub, emergent, and aquatic bed Cowardin vegetation communities. Dominant vegetation includes salmonberry, Pacific willow, hardhack spirea, skunk cabbage, and duckweed. This wetland contains multiple hydrogeomorphic classes including lake-fringe, riverine, and depressional. Surface water and soil saturation were observed at several locations within the wetland during the site visit. Wetland B is characterized as a narrow lake-fringe wetland with scrub-shrub and forested Cowardin vegetation communities. The main source of hydrology to this wetland is Steel Lake. Dominant vegetation included Western red cedar in the canopy, with spirea, salmonberry, and some Labrador tea in the understory. Redondo Creek Redondo Creek is broad and flows at a low gradient through the study area (from Steel Lake north to South 304th Street). The OHWM of Redondo Creek appears to be largely associated with, and very similar to, the level of Steel Lake. Furthermore, while delineating Wetland A along the creek corridor, it was determined that the OHWM of Redondo Creek coincided with the majority of Wetland A boundary flags (with the exception of flag 1-45). This determination was based on the presence of nearby surface water (presumably slow-moving Redondo Creek) during the site visit and the topography of the area; Wetland A is almost exclusively located within bed and bank features created by Redondo Creek. Steel Lake Stream and Wetland Delineation Review Study Ed Kim July 2014 Page 4 There is a natural fish barrier located downstream of the study site (SalmonScape, FPARS, communication with Matt Herrera) that prevents access to this portion of Redondo Creek by anadromous fish species. Steel Lake The OHWM of Steel Lake is contiguous with the flagged boundaries of Wetlands A and B. Between these wetlands, flags 1-14 through 1-20 also mark the OHWM of the lake. Local Regulations The City of Federal Way regulates wetlands and streams under Federal Way Revised Code (FWRC), Chapter 19.165 “Streams” and Chapter 19.175 “Regulated Wetlands.” Shorelines are regulated under Title 15, “Shoreline Management.” Wetlands A and B are considered Category II wetlands per FWRC. Category II wetlands require a standard buffer width of 100 feet. Redondo Creek is considered a minor stream due to the natural fish barrier located downstream of the project site. This classification corresponds with the City’s assessment of the stream based on communication with Matt Herrera during the on-site meeting. Minor streams require a standard buffer width of 50 feet. Per 15.05.080 “Shoreline residential environment,” a minimum shoreline setback of 50 feet is required from the OHWM of Steel Lake. This setback is only relevant where no wetland exists along the shore of Steel Lake (flags 1-14 through 1-20). Disclaimer The information contained in this letter or report is based on the application of technical guidelines currently accepted as the best available science and in conjunction with the manuals and criteria outlined in the methods section. All discussions, conclusions and recommendations reflect the best professional judgment of the author(s) and are based upon information available to us at the time the 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. Steel Lake Stream and Wetland Delineation Review Study Ed Kim July 2014 Page 5 Please call if you have any questions or if we can provide you with any additional information. Sincerely, Katy Crandall, WPIT Ecologist Enclosures