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HomeMy WebLinkAboutTAL-1952 Unico Longacres Existing Conditions TEXT ONLY29 April 2022 TAL-1952 Jill Ding, Senior Planner City of Renton Community and Economic Development 1055 South Grady Way Renton, WA 98057 Via Email: jding@rentonwa.gov RE: Critical Areas – Existing Conditions Letter Report Dear Ms. Ding: This letter provides the Executive Summary for the Critical Areas – Existing Conditions Letter Report. The full report is attached for your review. Executive Summary The attached Letter Report prepared by Talasaea Consultants analyzes existing wetlands, stormwater ponds, and other features at the subject property commonly known as Longacres (the“Campus”) in compliance with City of Renton’s critical areas regulations (RMC 4-3-050). The Letter Report informs the entitlement and development of a proposed Sounders FC training facility (the “Site”), located on a portion of the Campus). Figure 4 provides a Site Plan for the Sounders FC training facility. The Campus has been subject to various developments over the past century, including the Longacres horse racetrack and a Boeing Headquarters. These developments have resulted in extensive modifications to the Campus, including development of existing structures, stormwater management systems, on-site wetland mitigation, driveways, and surface parking. The Sounders FC training facility proposal includes the development of five new soccer training pitches, a keeper training area, the development of a new maintenance facility and restroom facilities, the use of a portion of an existing structure, a deck addition to this existing structure, and realignment of existing trails at the Site. The proposal also includes the removal of parking spaces. Figure 4 in the report provides a site plan for the proposal. The Letter Report concludes that only Wetland A is subject to the City’s critical areas regulations as it relates to the entitlement and development of the Site. This Letter Report identifies the applicable buffer, code-authorized buffer alteration and applicable mitigation. The Letter Report also concludes: Ms. Jill Ding 29 April 2022 Page 2 of 3 Pond B Pond B is extensively documented as a stormwater drainage pond. Pond B was expressly not included in the Longacres Mitigation Plans prepared by Shapiro and Associates in 1998 and 1999, and, accordingly, Pond B has not been utilized for wetland mitigation. Thus, Pond B is not regulated under the City’s critical areas regulations pursuant to RMC 4-3-050B.1 Any maintenance, repair, or expansion of Pond B associated with stormwater storage capacity would also be exempt from critical areas regulations pursuant to RMC 4-3-050C.3. Feature D Feature D fails to satisfy the hydrology requirements for a wetland, and therefore does not meet all the wetland criteria set forth in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineers 2010). Feature G Feature G is a stormwater treatment facility that has not been utilized as wetland mitigation. Thus, Feature G is also not regulated under the City’s critical areas regulations pursuant to RMC 4-3-050-B. 1 RMC 4-3-050B.1 provides, “Regulated wetlands do not include those artificial wetlands intentionally created from non-wetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway.” Ms. Jill Ding 29 April 2022 Page 3 of 3 Wetland A, Pond B, Feature D, and Feature G are identified in the image above and also shown in Figure 3 of the report. The Site does not include any other wetlands, critical area buffers, stormwater ponds, or features that would otherwise impact this proposal. The Letter Report includes the following information: 1. Property Location and Proposal 2. Property Description and Current Land Use 3. Proposed Development 4. Past Land Use and Historical Documentation 5. Field Investigation and Findings 6. Compliance with Critical Areas Regulations for Buffer Alterations (RMC 4-3-050J) Attachments 1– 14 Figures 1 – 4 We ask that the City respond to this letter confirming that: 1. Pond B, Feature D, and Feature G are not subject to the City’s critical area regulations pursuant to RMC 4-3-050B.1; 2. Wetland A is a Category II wetland with moderate habitat scores; and 3. Field 1 and the Goal Keeping Area (as identified in the Site Plan on Figure 4) are low intensity uses subject to a 100-foot buffer pursuant to RMC 4-3-050G.2, note 7 and RMC 4-11-120. Should you have any questions or require additional information at this time, please feel free to contact Jacob Prater or me at (425) 861-7550. Thank you. Sincerely, TALASAEA CONSULTANTS, INC. William E. Shiels Principal Attachment: Critical Areas – Existing Conditions Letter Report 29 April 2022 TAL-1952 Jill Ding, Senior Planner City of Renton Community and Economic Development 1055 South Grady Way Renton, WA 98057 Via Email: jding@rentonwa.gov REFERENCE: Longacres Unico Property Located in Renton, Washington SUBJECT: Critical Areas – Existing Conditions Letter Report Dear Ms. Ding, Talasaea Consultants has prepared this Existing Conditions report in collaboration with Unico Properties, the Seattle Sounders FC, Coughlin Porter Lundeen (CPL), and others to address the Seattle Sounders FC Performance Center that is proposed for construction on the Longacres Office Park property in Renton, Washington (Figure 1). This report includes descriptions of the property location and the proposed development, a comprehensive review of past documents which address development of the property since 1990, and a current field evaluation of the subject property for the presence of critical areas that could potentially impact development proposals. 1 Property Location and Proposal The Seattle Sounders FC Performance Center at Longacres is proposed to be located at the Longacres Office Park in Renton, Washington (the “Campus”, Figure 1).1 The approximately 108-acre Campus is composed of 18 parcels located west of Oakesdale Avenue SW in Renton, Washington (Figure 2). The Sounders “Site” accounts for seven of these parcels (King County tax parcels 2423049022, 0886700110, 0886700120, 0886700130, 0886700140, 0886700220, and 0886700370). Referencing the Boeing Longacres Property Second Amended Binding Site Plan (King County Recording No. 20050504000673, City of Renton, King County, WA; the “BSP”), the Site occupies lots 11, 12, 13, 14, and 20, and a portion of office building 25-20 located on lot 22 of the BSP (see Attachment 13). Shared parking facilities are located on lot 21 of the BSP, and some Sounders’ specific parking is proposed on a portion of lot 22 and into lot 11. The Site (excluding the office building and shared parking) is approximately 22 acres in size and is bordered to the west by Tracts A 1 The Campus is composed of the totality of the BSP, approximately 108-acres in size, located within a portion of the SE 1/4 of Sec. 24, Township 23N, Range 4E, W.M.. The Campus was recently purchased by Unico, which independently has plans to redevelop a substantial portion of the Campus property in the future. Ms. Jill Ding 29 April 2022 Page 2 of 38 and B of the BSP (the “Tracts”). The Site, including Building 25-20 and shared parking, is bordered on the east by Oakesdale Avenue SW, which provides access to the Site. The Sounders will develop a field complex on the Site, which will include five (5) full-size soccer pitches, a goalkeeper training field (“GK Field”), associated improvements, and parking. This Report addresses the existing conditions of the Site and adjacent Tracts, and includes a slightly expanded study area to capture related aspects of the landscape. No adjacent properties were accessed without owner permission; thus, our assessment of adjacent properties is based on visual observation and knowledge of work previously completed by Talasaea Consultants and past consultants. The Site, and approximately 300 feet surrounding the Site, are referred to jointly as the “study area.” 2 Property Description and Current Land Use The Campus has undergone extensive redevelopment over the past century. Aside from the obvious built environment captured by the buildings and associated parking areas, much of the Campus has undergone manipulation since the 1930s, including the creation of stormwater Pond B on Tract B and other man-made drainage features. The majority of the eastern and northern portions of the Campus are developed and feature several large office buildings and associated parking areas, with various other access roads and infrastructure throughout the Campus (Figure 3). The Site borders two large ponds (Wetland A and Pond B, discussed in Section 5) and borders on or includes various other stormwater features. Some of these features were the result of stormwater facilities and development-related mitigation associated with the initial Boeing development that took place during the 1990s and early 2000s (discussed in Section 5 below). The areas of the Site directly adjacent to the building and parking areas are vegetated by maintained lawn and other landscape plantings. Other plant communities across the Site are composed of native tree species, including black cottonwood (Populus balsamifera ssp. trichocarpa) and red alder (Alnus rubra), with occasional Douglas-fir (Pseudotsuga menziesii), western redcedar (Thuja plicata), bigleaf maple (Acer macrophyllum), and others. The Site includes several species of native shrubs and saplings including Sitka willow (Salix sitchensis), salmonberry (Rubus spectabilis), vine maple (Acer circinatum), and others. Throughout the Site, there is a prevalence of non-native and invasive Himalayan blackberry (Rubus armeniacus), reed canarygrass (Phalaris arundinacea), and English ivy (Hedera helix). 3 Proposed Development The Sounders’ development is proposed to be constructed in one or two construction phases. This Existing Conditions Letter Report addresses the Sounders Site and Tracts A and B, for the Sounders FC proposal, and includes: • Construction of five (5) full-sized training fields and a GK Field; • Construction of a new maintenance shed and an outdoor restroom facility; • The use of approximately 50,000 SF of an existing structure that will house the club’s operations, including front office personnel, first, second, and academy teams, and other uses associated with the club; Ms. Jill Ding 29 April 2022 Page 3 of 38 • Deck addition to the existing structure; • Realignment of existing pervious and/or impervious trails; • Removal of approximately 150 surface parking stalls for the placement of training pitches; and • Relocation of removed parking stalls for Sounders’ facility and use. The current design places the five (5) fields and the GK Field positioned in the western portion of the Site, adjacent to the southeast side of Wetland A and east side of Pond B (Figure 4). Several project elements adjacent to Tract A will require a critical areas alteration to minimize or avoid wetland buffer impacts. The extent of the buffer impact from the pitches and GK Field is dependent upon the City’s confirmation that field use is low intensity, which is a determining factor for applicable buffer width. Parking areas would not be considered low intensity, and therefore would be subject to the standard wetland buffer width for the wetland classification. 3.1 Avoidance The proposed field placement was modified and refined to the greatest extent possible to avoid impacts to Wetland A and its associated buffer (see Section 5). Field 1 is programmatically required to have direct access to the training facility within Building 25-20, so its location is fixed. The GK Field is programmatically linked to Field 1, and the remaining pitches (Fields 2 through 5) are proposed to the south of Field 1 to avoid impacts to the wetland buffer. To facilitate moving the fields south, some existing surface parking stalls are proposed to be removed to create additional space for the fields and to minimize encroachment into the Wetland A buffer.2 Wetland A is rated as a Category II wetland with a moderate habitat score. Thus, the code establishes a 150-foot standard buffer (for nonexempt uses that are not low intensity land uses), and a 100-foot buffer for low intensity land uses (RMC 4-3-050.G.2)3. Currently, Wetland A on the Site is bordered by a paved trail. The code defines low impact land use as those uses “which are not likely to have a significant adverse impact on critical areas because of the low intensity of the use, minimal levels of human activity, limited use of machinery or chemicals, site design or arrangement of b uildings and structures, incorporation of mitigation measures, or other factors." Additional details pertaining to Wetland A are discussed in further detail in Section 5 below. Depending upon the determination of whether the soccer pitches and keeper training area are low intensity land uses, buffer alterations will be calculated from standard 150-foot buffer or from the low- 2 Field 1 and the GK Field, located east of a trail that borders Wetland A, will be the least intensely used fields of the Sounders FC Performance Facility. These are grass fields, which will be used approximately 2-5 hours per day, exclusively for professional soccer training and team activities. The fields will be fenced, and although lighting will be provided, Field 1 and the GK Field will not be used for evening practices, so the lights would be used rarely. During the growing season these grass fields would be mowed approximately every 2-3 days, with mowing occurring less frequently outside the growing season. Surface runoff from the fields will be collected primarily through under-field drains, and will be routed through an enhanced stormwater quality treatment and detention system prior to being discharged to a pond directly upstream of Wetland A. 3RMC 4-3-050G.2, note 7 states, “Low intensity land uses include but are not limited to the following: unpaved trails, low intensity open space (hiking, bird-watching, preservation of natural resources, etc.) and utility corridor without a maintenance road and little or no vegetation management." Ms. Jill Ding 29 April 2022 Page 4 of 38 impact 100-foot buffer (Figure 4). Pond B, Feature D, and Feature G (discussed in Section 5 below) are not wetlands subject to critical areas regulations and do not require buffers (RMC 4-3-050B.1).4 4 Past Land Use and Historical Documentation The Campus functioned as a thoroughbred horse racetrack for much of the 20th century until Boeing purchased the property in 1990. Boeing developed a Customer Services Training Center (CSTC) in the early 1990s, and in the mid-1990s Boeing constructed the Longacres Office Park (“LOP”) (Attachment 1). Boeing prepared extensive permitting reports and environmental documentation to entitle the LOP. A list of documents considered is included in Attachment 2. These documents include, but are not limited to: • Jurisdictional Wetland Determination for Longacres Park Development (April 1992, Attachment 3); • Existing Habitat Conditions and Wildlife Study Report (June 1993, Attachment 4); • Jurisdictional Wetland Determination (August 1998, Attachment 5); and • Surface Water Management Project and Conceptual Mitigation Plan published in December 1998 (Attachment 6) and revised January 1999 (Attachment 7). The reports noted above were prepared by Shapiro and Associates, Inc (“Shapiro”). In addition, this Letter Report will also discuss the Drainage Report and Conceptual Drainage Plan prepared by Sverdrup Civil, Inc (September 1998, Attachment 8). These reports were instrumental in preparing the Environmental Impact Statement used to entitle LOP through a development agreement executed by Boeing and the City in December 2000. More recently (2015-2021), various consultants have prepared wetland delineation reports and biological assessments for all or portions of the Campus. These documents include: • Biological Assessment and Critical Areas Study prepared by Terracon Consultants, Inc (December 2015, Attachment 9); • Wetlands Delineation and Regulatory Analysis Memorandum prepared by Amec Foster Wheeler (September 2016, Attachment 10); and • Delineation of Wetlands and Other Waters report prepared by NV5 (March 2021, Attachment 11). The City’s critical areas ordinance exempts all permitted stormwater detention facilities not used for wetland mitigation (RMC 4-3-050B.1). The three reports identified above did not address this exemption, or they misinterpreted background information on permitted stormwater detention improvements. Thus, these reports could be misleading without additional permitting background 4 RMC 4-3-050B.1 provides, “Regulated wetlands do not include those artificial wetlands intentionally created from nonwetland sites, including, but not limited to, irrigation and drainage ditches, grass -lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway.” Ms. Jill Ding 29 April 2022 Page 5 of 38 information and context. Therefore, it is necessary to explore, in detail, several documents pertaining to the development of the LOP to differentiate between regulated and non-regulated features of the property. Jurisdictional Wetland Determination for Longacres Park Development, Shapiro and Associates, Inc, April 1992 As one of the more preliminary attempts at a wetland assessment on the LOP property, Shapiro conducted a wetland investigation throughout 1991 in order to formally delineate all wetlands on the property. This “1992 Shapiro Report” was published in 1992 (Attachment 3). The study area recognized areas to the south and east but focused their work around the main track area (current day Wetland A and Pond B, Figure 3 of the 1992 Shapiro Report, between pages 12 and 13). Shapiro established 25 different test plots across the LOP and identified a total of five (5) wetlands that correspond with Figure 4 (between pages 15 and 16) of this 1992 Shapiro Report (see below image), with one wetland corresponding with the marsh located to the south of the LOP. As demonstrated in the following reports, many of the identified wetlands were filled or modified as a result of the Longacres redevelopment. Thus, the 1992 Shapiro Report provides a baseline for the Site before the redevelopment of Longacres. Figure 4 from Shapiro and Associates, Inc, April 1992 Ms. Jill Ding 29 April 2022 Page 6 of 38 Existing Habitat Conditions and Wildlife Study Report, Shapiro and Associates, Inc, June 1993 In June of 1993, Shapiro and Associates prepared a comprehensive study of existing habitat areas and wildlife use of the LOP Site (Attachment 4). This “1993 Shapiro Report” assessed both the quality and quantity of habitats and the abundance of species of wildlife using the property. This 1993 Shapiro Report identified four different habitats as existing within its study area: mowed racetrack infields, a southern open field area, marsh areas in the southeast, and a constructed environment of buildings and parking lots. The study area of the 1993 Shapiro Report was much broader than the current study area, but its characterizations of the areas within Tract A and Tract B are pertinent. It is also relevant to note that the “mowed infield” is the proposed location of the Sounders field complex. Although the 1993 Shapiro Report focused heavily on the wildlife found on the property, there was mention of Category III wetlands found in low-lying swales and drainage ditches in the mowed infields, and it identified the marsh located to the south of the property as a Category II or III wetland (see Figure 3 of the 1993 Shapiro Report, p. 12). Other figures included in the 1993 Shapiro Report further illustrate potential wetland areas without providing a naming scheme, formal ratings, or formal wetland determination data forms. Like the 1992 Shapiro Report, the 1993 Shapiro Report provides a baseline for the Site prior to the redevelopment of Longacres. Jurisdictional Wetland Determination, Shapiro and Associates, Inc, August 1998 In 1998, Shapiro prepared a Jurisdictional Wetland Determination report in order to re-delineate the features previously characterized as wetlands under the 1987 U.S. Army Corps of Engineers (“Corps” hereinafter) methodology (Attachment 5). Furthermore, this “1998 Shapiro Report” confirmed that several wetlands were filled between 1991 and 1998 as part of other site development activities; thus, an updated delineation was necessary ahead of further LOP construction. The wetland labeling system used in the 1998 Shapiro Report is different than those used in later reports for the Longacres Property and those used in this Existing Conditions Report. The 1998 Shapiro Report omits the existing “main pond” area and surrounding wetland area within the “Customer Services Training Center” property, limiting delineations to the other parcels. Their 1998 report designates a “Wetland A” and “Wetland B” in the southern extent of the main pond and surrounding wetlands. Only their Wetland B falls within the current Wetland A area (1998 Shapiro Report, Figure 2, p. 8, see image below). Pond B had not been planned or created at the time of the 1998 report. Thus, the 1998 Shapiro Report’s statement that “portions of Wetland A and B still exist, and areas impacted by development have been mitigated”5 provides no bearing on the status of Pond B as identified in this current report. As shown below, the 1998 Shapiro Report identified eight (8) wetlands within the study area (compared to the five (5) identified in the 1992 report), and further divided the wetlands into 15 sub-wetlands. Seven (7) of the 15 wetlands lacked at least one of the qualifying criteria and were considered non - wetlands or were considered non-regulated due to being perched on fill. These non-regulated wetlands included Wetlands G, H3, I2, I3, J, Ka, and L2 per Figure 2 of the 1998 Shapiro Report (see below). Conclusion: Pond B did not exist at the time of the 1998 Shapiro Report, and therefore was not the regulated wetland identified in the report. Pond B was not used for any wetland mitigation. 5 1998 Shapiro Report, Attachment 5, p. 1 (4th paragraph in the Executive Summary). Ms. Jill Ding 29 April 2022 Page 7 of 38 Figure 2 of Shapiro and Associates, Inc., August 1998 (with insert of existing conditions from Talasaea, 2022). Ms. Jill Ding 29 April 2022 Page 8 of 38 Surface Water Management Project and Conceptual Mitigation Plan, Shapiro and Associates, Inc , December 1998, revised January 1999 The Surface Water Management Project and Conceptual Mitigation Plan prepared by Shapiro and Associates in December of 1998 (Attachment 6, the “1998 Mitigation Plan”) and revised in 1999 (Attachment 7, the “1999 Mitigation Plan”) are the most helpful documents to understand previous mitigation and current regulatory standing. Collectively, the 1998 and 1999 Mitigation Plans are referred to as “Mitigation Plans” hereinafter. The Mitigation Plans assessed existing conditions ahead of the LOP and the construction of the associated Surface Water Management Plan (“SWMP”), analyzed the impacts resulting from the construction of the LOP and SWMP, and identified appropriate compensatory mitigation required to offset impacts to critical areas. The 1999 Mitigation Plan identified the same wetlands addressed in the 1998 Shapiro Report. (1999 Shapiro Report, Figure 3, p. 10, see image below). None of the wetlands, with the exception of Wetland A and Pond B (discussed in Section 5), were identified by the Mitigation Plans as existing on the property prior to the construction of the LOP. The 1999 Mitigation Plan clearly documents Pond B (as it is referred to in this Existing Conditions Report) as a stormwater facility, not a wetland regulated under the City’s critical areas ordinance. The following provisions in the 1999 Mitigation Plan are particularly informative: Page 3: “The proposed SWMP will create a combined wetpond/detention pond necessary to meet water quality requirements for future development on the site. The wetpond/detention pond mitigation will create or restore 2.15 acres of wetlands that will provide ter tiary water quality enhancement after flows through catch basins, wet vaults, and wet ponds. These wetlands associated with the wetpond are not included as part of the wetland mitigation.” Page 13: “The project will entail creation of a stormwater pond where one presently does not exist. While this wet pond will be nearly identical in appearance to the mitigation wetland, it is not included within the mitigation area.” Page 16: “Immediately south of the wetland mitigation area will be a stormwater detention and water enhancement pond. While not being used as wetland mitigation, it will be landscaped similar to the wetland mitigation area with open water, floating leaved, emergent, scrub -shrub, and forested components.” These findings are consistent with the 1998 Mitigation Plan. For example: Page 15: “Immediately south of the wetland mitigation area will be a stormwater detention and water quality enhancement pond. While not being used as wetland mitigation, it will be landscaped similar to the wetland mitigation area with open water, floating leaved, emergent, scrub-shrub and forested.” Ms. Jill Ding 29 April 2022 Page 9 of 38 Figure 3 in Shapiro and Associates, Inc, January 1999 Ms. Jill Ding 29 April 2022 Page 10 of 38 Page 14 of the 1998 Shapiro Report provides Figure 3 (see image below) that clearly delineates proposed stormwater treatment pond, which corresponds to Pond B as identified in this report (note the north arrow pointing to the left): Looking broadly across LOP, pursuant to the 1999 Mitigation Plan, the construction of the LOP SWMP was found to result in 1.4 acres of direct wetland fill. Impacts were located in the central portion of the main track (present day Wetland A, Figure 3), and the practice track located east of Oakesdale Avenue Southwest. To mitigate for the direct wetland fill, the 1999 Mitigation Plan proposed the preservation of 10.9 acres of wetland to the south of the LOP Site (south marsh area, located south of the proposed fields), the creation and/or restoration of 3.3 acres of wetland on the LOP Site, and 1.5 acres of wetland reserve on the CSTC Site (see Figure 3 within Attachment 7). The 1999 Management Plan clearly outlines the location of mitigation, and explicitly states that although the south pond (Pond B) will be nearly identical in appearance to the mitigation wetlands, “it is not included within the mitigation area” (1999 Mitigation Plan, p. 13, Attachment 7). The stormwater treatment system as outlined in the 1999 Mitigation Plan was designed to direct water from the primary catch basin into Pond B (referred to by Shapiro as the “wet pond”), then into the mitigation area (today’s Wetland A) and eventually through the CSTC mitigation wetlands and into Springbrook Creek. Conclusion: The south pond (i.e., Pond B) is a stormwater pond and not a wetland. The Mitigation Plans excluded Pond B from all wetland mitigation measures. Drainage Report for Conceptual Drainage Plan, Sverdrup Civil Inc, September 1998 As part of a submittal to the City of Renton, the Drainage Report for Conceptual Drainage Plan (“Drainage Report”) was prepared to meet the requirements of the City of Renton Drainage Report for Conceptual Drainage Plan Content List (Attachment 8). This document covers many of the same Figure 3 in Shapiro and Associates, Inc, August 1998 Ms. Jill Ding 29 April 2022 Page 11 of 38 details expanded upon by the 1999 Mitigation Plan, including the expansion of the CSTC main pond (present day Wetland A, Figure 3) and associated wetlands as mitigation for the SWMP construction, as well as the construction of a combined “wetpond/detention pond” (present day Pond B, Figure 3) south of the mitigation area. The Drainage Report uses a slightly different naming scheme than that employed by the 1999 Mitigation Plan. The Drainage Report terms present day Wetland A as the “CSTC Main Pond,” while referring to the wetpond/detention pond (present day Pond B) south of the CSTC Main Pond as “Pond D.” As part of the construction of Pond D (present day Pond B, Figure 3), a temporary water quality treatment and control pond was constructed, which directed water into Pond D. This Pond, referred to as Pond B in the Drainage Report, is the location of present-day Feature G (Figure 3). This temporary water treatment pond was constructed sometime during the late 1990s and was removed within two years following the construction of the present-day Pond B (Figure 3). No wetlands were identified in the Feature G area prior to the construction of the temporary water treatment pond, and it was proposed that the pond would be filled once no longer needed. Conclusion: The Drainage Report Pond D (i.e., present-day Pond B) and Drainage Report Pond B (i.e., present-day Feature G) were stormwater ponds and not wetlands. Biological Assessment and Critical Areas Study, Terracon Consultants, Inc, December 2015 The Biological Assessment and Critical Areas Study prepared by Terracon Consultants, Inc (December 2015) was intended to review the Longacres Business Center Phase II development project which now houses both the Kaiser Permanente and Jeanne Lester Offices (Attachment 9). This project included the construction of two buildings found on the southern portion of the Campus today, as well as the detention pond located directly north of those buildings. These improvements are outside the Site of the current proposal. The Terracon report briefly discusses the wetland features found on the LOP site as indicated by U.S. Fish and Wildlife Service’s National Wetland Inventory (NWI) and references the Shapiro and Associates documents discussed above. No further discussion regarding wetlands found on the LOP Site is included. Wetlands Delineation and Regulatory Analysis Memorandum, Amec Foster Wheeler, September 2016 The Wetlands Delineation and Regulatory Analysis Memorandum prepared by Amec Foster Wheeler (the “Amec Report,” Attachment 10) was prepared for the Boeing Company to determine existing wetland boundaries, perform wetland functional assessments, conduct regulatory review of the jurisdictional status of the north and south ponds (what we refer to today as Wetland A and Pond B), and to provide required offset for regulatory buffers to these features. The Amec Report includes a review of the Mitigation Plans and further expands on details pertaining to the designed mitigation and stormwater management. Additionally, the Amec Report discusses details pertaining to Corps jurisdiction and regulated features, as well as aquatic systems resulting from compensatory actions permitted under the Clean Water Act and those which have a significant nexus with traditional navigable waters or relatively permanent waters. Although other wetlands identified by NWI and the City of Renton are discussed in the report, the work focused primarily on the north and south ponds (present-day Wetland A and Pond B, Figure 3). Ms. Jill Ding 29 April 2022 Page 12 of 38 Pursuant to the Washington State Wetlands Rating System for Western Washington: 2014 Update (Hruby, 2014), both ponds were rated as Category II wetlands requiring 150-foot standard buffers. A section of the Amec Report entitled “Regulatory Status Evaluation,” includes a discussion of the regulatory status of present-day Wetland A and Pond B. The report initially recognizes the exclusion of the south pond from the original mitigation outlined by the 1999 Mitigation Plan, which is consistent with all previous reports produced for the LOP. However, the report then goes on to state that, because both ponds were created under the Mitigation Plans, they are both subject to applicable wetland regulations. The Amec Report’s conclusion regarding Pond B is not supported by the Mitigation Plans (Attachments 6 and 7) and it is inconsistent with Renton Municipal Code, which exempts stormwater facilities unless the stormwater facility was also utilized for wetland mitigation (RMC 4-3-050B). The Amec Report does not provide any citation to support its conclusion that present-day Pond B was converted from a stormwater facility into a wetland subject to critical areas regulations. The Amec Report’s conclusion is in direct contradiction with the express language of the Mitigation Plans cited above (e.g., 1999 Mitigation Plan, pp. 3, 13, 15 and 16 and 1998 Mitigation Plan pp. 14-15). Thus, we disagree with the Amec Report’s conclusion for present-day Pond B, as the north pond (Wetland A, Figure 3) was included in the Mitigation Plans as a wetland, and the south pond (Pond B, Figure 3) was created for stormwater management only (although landscaped to be aesthetically identical to the north pond). The Mitigation Plans leave no doubt that the south pond was expressly “not included as part of the mitigation area.” 1999 Mitigation Plan, p.3 (Attachment 7) Conclusion: Pond B was a stormwater pond and not a wetland. The Mitigation Plans expressly excluded Pond B from any wetland mitigation measures. Delineation of Wetlands and Other Waters, NV5, March 2021 The Delineation of Wetlands and Other Waters report prepared by NV5 (“NV5 Report,” March 2021, Attachment 11) outlines a full delineation and documentation of all regulated and non-regulated features identified on the property. In a brief review of past site alterations, the NV5 Report (2021) states that the 1999 Mitigation Plan includes the creation of both the north and south ponds (present day Wetland A and Pond B, Figure 3), and notes that the south pond was created to provide water quality improvement, water storage, and wetland habitat. The NV5 Report expanded their area of research beyond that of the Amec Report and investigated areas similar to those investigated by Talasaea Consultants. The NV5 Report identified seven (7) wetlands and rated them according to the standard methodology in the Washington State Wetlands Rating System for Western Washington: 2014 Update (Hruby, 2014). Buffers were assigned according to the 2002 Renton Municipal Code (RMC) based on a recorded Development Agreement between Boeing and the City of Renton. The NV5 Report states “the purpose of the South Pond was to provide water quality improvement, water storage, and wetland habitat.”6 Similar to the Amec Report, the NV5 Report does not include any 6 NV5 Report, p. 5. Ms. Jill Ding 29 April 2022 Page 13 of 38 citation for this conclusion. The NV5 Report’s reference list cites the Amec Report. Thus, NV5’s conclusion likely relies on the Amec Report’s presumption that Pond B was used for mitigation under the Mitigation Plans, thereby incorrectly classifying a stormwater facility as a “wetland” subject to critical areas regulations. As noted above, the Amec Report’s conclusion regarding Pond B contradicts express language in the Mitigation Plans and is inconsistent with controlling code. The permit record demonstrates that the present-day Pond B was only permitted as a stormwater facility. 2003 and 2005 Binding Site Plans The Longacres’ Binding Site Plans (BSP) further support our wetland conclusions (Attachments 12 and 13). The 2003 and 2005 BSPs label Wetland A as “Wetland” with associated buffers. Similarly, the southern wetlands (located outside the Site for the report) are also labeled as “Wetland” with buffers identified. Consistent with the findings of this Letter Report, Pond B is not labeled as a wetland and there are no markings for wetland buffers surrounding present day Pond B. The 2003 and 2005 BSPs were approved by the City of Renton and not appealed. Conclusion: Taken together, the applicable wetland studies demonstrate that Pond B is, and Feature G was, stormwater ponds, and therefore not wetlands subject to critical areas regulations. This conclusion is based on information received through an extensive public records request from the City of Renton, permit records provided by Boeing, and materials available at the Puget Sound Archives. 5 Field Investigation & Critical Areas We evaluated the Site and the surrounding areas of the Campus on February 22 and 25, and March 1, 2022. During the February site visits, Talasaea staff performed a full Site reconnaissance and delineation of all wetland areas within the study area (Figure 3). During the site visit on March 1st, the remaining area of the property (outside of the primary study area) was documented, although no formal test plots or delineations were recorded. Although the entire property spans both sides of Oakesdale Avenue SW, our investigation focused on the areas directly adjacent to the north and south ponds (present day Wetland A and Pond B discussed below). Although we recognize that there may be other critical areas found east of Oakesdale Avenue SW, Oakesdale was a logical eastern boundary for the present study, and those features are not discussed herein. Wetland determinations were made using the routine approach described in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineers 2010). Plant species were identified according to the taxonomy of Hitchcock and Cronquist (Hitchcock, et al. 2018). Taxonomic names were updated, and plant wetland status was assigned according to the National Wetland Plant List, Version 3.5 (U.S. Army Corps of Engineers, 2020). Wetland classes were evaluated with the U.S. Fish and Wildlife Service’s system of wetland classification (Cowardin, et al. 1979). Vegetation was considered hydrophytic if greater than 50% of the dominant plant species had a wetland indicator status of facultative or wetter (i.e., facultative, facultative wetland, or obligate wetland). Wetland hydrology was evaluated based on the presence of hydrologic indicators listed in the Corps’ Regional Supplement. These indicators are separated into Primary Indicators and Secondary Indicators. To confirm the presence of wetland hydrology, one (1) Primary Indicator or two (2) Secondary Ms. Jill Ding 29 April 2022 Page 14 of 38 Indicators must be demonstrated. Indicators of wetland hydrology may include, but are not necessarily limited to: drainage patterns, drift lines, sediment deposition, wat ermarks, stream gauge data and flood predictions, historic records, visual observation of saturated soils, and visual observation of inundation. Soils on the Site were considered hydric if one or more of the hydric soil indicators listed in the Corps’ Regional Supplement were present. Indicators include presence of organic soils, reduced, depleted, or gleyed soils, or redoximorphic features in association with reduced soils. Background information from the following sources was reviewed prior to field investigations: • US Fish and Wildlife Service (USFWS) Wetlands Online Mapper (National Wetlands Inventory, NWI) (https://fwsprimary.wim.usgs.gov/wetlands/apps/wetlands-mapper/); • Natural Resources Conservation Service (NRCS), Web Soil Survey (www.websoilsurvey.nrcs.usda.gov/app); • King County Critical Areas Database (King County IMap, 2022); • City of Renton Environmental Data (Renton COR Maps, 2022); • Washington Department of Fish and Wildlife (WDFW) Priority Habitats and Species (PHS) Database on the Web (https://geodataservices.wdfw.wa.gov/hp/phs/); • Washington Department of Natural Resources (DNR) Natural Heritage GIS database, 2022; • Fish usage data from SalmonScape (http://apps.wdfw.wa.gov/salmonscape/map.html), StreamNet (https://www.streamnet.org/home/data-maps/sn-mapper/ and the Northwest Indian Fisheries Commission (https://geo.nwifc.org/swifd/); • Orthophotography from Earth Explorer (2022), and Google Earth (2022); and • Previous Reports Prepared for the Property (various, discussed above). Three (3) wetlands were identified within the area of the property investigated. Two (2) other features were identified within the same area and formally documented and determined not to be regulated features. For the sake of completeness, these features are still discussed below. Various other areas that have previously been identified as wetlands (Wetland D and Wetland G per the 2021 NV5 report) were also investigated and documented. These features were found not to be wetlands but are also discussed herein. Included in the discussion of each feature below are the vegetative, hydrologic and soil conditions of the feature (aside from Feature D and G), a brief review of the past documentation of the feature, and a general regulatory conclusion and associated rationale. To avoid potential confusion regarding the wetland naming schemes and how they compare to past reports for the property, a naming summary has been provided in Table 1. Ms. Jill Ding 29 April 2022 Page 15 of 38 Table 1: Naming Scheme of Individual Features by Report. Talasaea Consultants (2022) Shapiro and Associates (1999) Sverdrup Civil (1998) Amec Foster Wheeler (2016) NV5 (2021) Wetland A Mitigation area / Mitigation Wetland CSTC Wetland / Detention Pond North Pond Wetland A Pond B Wet pond / detention pond Wet pond / detention pond / Wetland D South Pond Wetland B Wetland C Not Explicitly Identified Not Explicitly Identified Not Explicitly Identified Wetland C Feature D Not Explicitly Identified Not Explicitly Identified Not Explicitly Identified Wetland D Wetland F Not Explicitly Identified, potentially included as mitigation area CSTC Delta Area Not Explicitly Identified Wetland F & Wetland E Feature G Not Explicitly Identified Pond B Not Explicitly Identified Wetland G Ms. Jill Ding 29 April 2022 Page 16 of 38 5.1 Wetland A Wetland A is a Category II depressional wetland and the northern-most pond located on the property (Photo 1). Wetland A scored 7 points for Improving Water Quality, 8 points for Hydrologic Functions, and 6 points for Habitat Functions. RMC 4-3-050G.2 establishes a 150-foot standard buffer for Category II wetlands with moderate habitat scores. Wetland A hydrology is provided by direct precipitation, surface runoff, and from Pond B located to the south (discussed below). Pursuant to the 1999 Mitigation Plan, Wetland A was designed as part of the LOP SWMP and receives stormwater from the Campus. Vegetation within Wetland A is characterized by red alder, black cottonwood, salmonberry, slough sedge (Carex obnupta), and cattail (Typha latifolia). Soils within Wetland A were generally a dark, greyish brown (10YR 3/2 to 4/2 and 2.5Y 4/2) loam or silty clay loam dependent on the location within the Wetland. Dark yellowish brown to dark brown redox features (10YR 4/2 to 4/6) were commonly found within Wetland A (Attachment 14). The use of Wetland A as compensatory mitigation, as well as its use in stormwater treatment, is clearly explained by numerous reports previously prepared for the Site (Sverdrup Civil, 1998; Shapiro and Associates, 1999; Amec Foster Wheeler 2016). As compensatory mitigation, Wetland A was an expansion of a previously existing wetland (Shapiro and Associates 1992; 1993; 1998; 1999) and included the creation of wetland from previously upland areas. Due to its inclusion as compensatory mitigation in the mitigation plan outlined in the 1999 Mitigation Plan, this wetland is considered a regulated feature at the local, State and Federal levels. Photo 1: Aerial of Wetland A (Oriented North). Ms. Jill Ding 29 April 2022 Page 17 of 38 5.2 Pond B Pond B is a stormwater detention and treatment pond located directly south of Wetland A. Pond B hydrology is provided by direct surface flow during rain events and from the stormwater detention pond located to the south. Pursuant to the 1999 Mitigation Plan, Pond B is designed to receive and treat stormwater from the Campus. Vegetation within and adjacent to Pond B is characterized by red alder, black cottonwood, salmonberry, slough sedge, and cattail. Soils within Pond B are generally a black to dark, greyish brown (10YR 2/1 to 3/2) sandy or silty loam, dependent on the location within the Pond. Dark yellowish to grayish brown redox features (10YR 4/3 to 5/4) were commonly found within Pond B (Attachment 13). Unlike Wetland A, Pond B was not included as part of the compensatory mitigation for the construction of the LOP. This conclusion is supported in Section 4. Thus, Pond B is excluded from permits issued by the Corps and exempt from the City’s wetland critical area regulations. Per RMC 4-3-050B, “regulated wetlands do not include those artificial wetlands intentionally created from non-wetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities.” Pursuant to this section of the RMC, and considered concurrently with the previous documents prepared for the Site, we do not consider Pond B a regulated feature, and is instead a stormwater management facility. 5.3 Wetland C Wetland C is a Category II depressional wetland located to the northwest of Wetland A (Photo 2). Wetland C scored 7 points for Improving Water Quality, 8 points for Hy drologic Functions, and 5 points for Habitat Functions. RMC 4-3-050G.2 establishes a 150-foot standard buffer for Category II wetlands with moderate habitat scores (5-7). Although outside the Site, Wetland C was included in the study area due to its relative proximity to Wetland A and as part of the research into the 1999 Mitigation Plan. Wetland C hydrology is provided by direct surface flow during rain events and potentially from Wetland A during above average rain events. Although Wetland C is not explicitly mentioned by any reports predating the NV5 Report, we believe it was included as part of the mitigation outlined by the 1999 Mitigation Plan. Vegetation within Wetland C is characterized by red alder, Sitka willow, and hairy bitter cress (Cardamine hisuta). Soils within Wetland C are a dark grayish brown (2.5Y 4/2) silty clay loam with yellowish brown (10YR 5/8) redoximorphic features (Attachment 14). The potential use of Wetland C as compensatory mitigation, as well as its use in stormwater treatment, results in a regulatory standing similar to that of Wetland A. As compensatory mitigation, Wetland C was the result of the wetland creation and restoration outlined by the 1999 Mitigation Plan and is considered a regulated feature at the local, State and Federal levels. Ms. Jill Ding 29 April 2022 Page 18 of 38 5.4 Feature D Feature D is an upland area located upslope and east of Pond B. Both test plots conducted within Feature D failed to satisfy the requirements of a hydrology indicator, and one of the two test plots failed to satisfy the requirements of either a hydrology or hydric soil indicator. Feature D hydrology, when present, appears to be historically provided by an installed irrigation system which draws water directly from Pond B. Aside from the installed irrigation system, hydrology can only otherwise be provided by direct precipitation due to local topography. Feature D is an area that is indicative of intentional plantings designed to make the area visually appear as a wetland. Vegetation within Feature D is almost entirely dominated by slough sedge, with various red alders, black cottonwoods, and Sitka willows. The soil profile within Feature D was characterized by a dark brown (10YR 3/3) coarse sandy loam overlying a very dark gray to dark brown (10YR 3/1to 3/3) dense restrictive layer composed of silty loam/clay (Attachment 14). Because the area does not meet the criteria of a wetland according to the methodology set forth in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineers 2010), a regulatory discussion is not warranted. Conclusion: Feature D does not meet wetland designation criteria and is not a regulated wetland. Photo 2: Aerial of Wetland C (Oriented Southeast). Ms. Jill Ding 29 April 2022 Page 19 of 38 5.5 Wetland F Wetland F is a Category II depressional wetland located to the east of Wetland A and directs water from Wetland A towards the CTSE Wetlands located east of Oakesdale Avenue SW (Photo 3). It is the only wetland located on the property where the open water habitat has any measurable flow, although the flow velocity is minimal. Wetland F scored 7 points for Improving Water Quality, 8 points for Hydrologic Functions, and 6 points for Habitat Functions. Pursuant to RMC 4-3-050G(2), Category II wetlands with moderate habitat scores (5-7) are subject to a standard 150’ buffer (Attachment 14). Wetland F hydrology is provided by direct surface flow during rain events and from Wetland A located to the west. Vegetation within Wetland F is similar to other wetlands found on the property, with a prevalence of red alder, Sitka willow, slough sedge, and several Western redcedars. Soils within Wetland F were generally dark grayish brown (10YR 3/2 to 4/2) sandy/silty loam. A gravel fill layer occupied the upper stratum of the soil profiles collected within and around Wetland F. Dark yellowish brown and strong brown redox features (10YR 3/6 to 4/4 and 7/5YR 5/8) were commonly found within Wetland F. Wetland F is not explicitly mentioned in the 1999 Mitigation Plan but is referred to as “CTSC Delta Area” by Sverdrup Civil (1998). Sverdrup Civil (1998) explains this area as a constructed wetland area designed to accept stormwater flows from the upstream site (Wetland A). Based on the figures included in the 1999 Mitigation Report, it appears to have not been included in the “wetland mitigation area” but Photo 3: Aerial of Wetland F (Oriented Northeast). Ms. Jill Ding 29 April 2022 Page 20 of 38 is highlighted as an existing wetland by the 1993 Existing Conditions Report prepared by Shapiro. Wetland F as it exists today is potentially a restoration and/or expansion of the pre-existing wetland. Conclusion: Due to the Wetland being identified prior to the construction of the LOP SWMP, Wetland F should be considered a regulated feature at the local, State and Federal levels. 5.6 Feature G Feature G is a depressional wetland located east of Pond B (Photo 4). Feature G hydrology is supported by both surface water flow during periods of above average precipitation, and by shallow groundwater flow. However, Feature G is also noted as being a site of stormwater treatment by the City of Renton (Photo 5) and indicates numerous private surface water mains entering and exiting the area. Vegetation within Feature G is characterized by a predominance of invasive species such as reed canarygrass and Himalayan blackberry with various other grass species such as bent grass (Agrostis sp.) and velvet grass (Hocus lanatus). The soil profile within Feature G is characterized by a dark gray (10YR 4/1) silty clay loam with strong brown (10YR 4/6) redoximorphic features overlying a dense, restrictive clay layer (Attachment 14). Feature G is identified by the NV5 Report. However, the Svedrup Draining Report (1998) outlines the construction of a “Pond D” (present day Pond B) and a temporary water quality treatment and control pond which directed water into Pond D. This Pond, referred to as “Pond B” in the Sverdrup Drainage Report (1998), is the location of present-day Feature G. This temporary water treatment pond was constructed sometime during the late 1990s and removed within two years following the construction of the present-day Pond B (Attachment 1). It is unclear how “Pond D” was removed or filled; however, Photo 4: Aerial of Feature G (Oriented Northwest). Ms. Jill Ding 29 April 2022 Page 21 of 38 no wetlands were identified in this area prior to the construction of the temporary water treatment pond by any reports published throughout the 1990s and early 2000s. Additionally, fragments of concrete and terracotta tile remaining from the previously constructed and filled stormwater ponds were removed from test plots examined within Feature G. Feature G is a non-regulated feature when these fragments are considered concurrently with the construction of roads, paved pathways and berms surrounding the feature, as well as the past construction and fill of the temporary “Pond D.” Pursuant to RMC 4-3-050B, this feature meets (1) exemption criteria of “wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway” and/or (2) the exemption criteria for an existing stormwater facility per photo 5 above. Conclusion: Feature G is not a regulated wetland. Photo 5: Surface Water System mapping of Pond B and Feature G from City of Renton COR Maps. Ms. Jill Ding 29 April 2022 Page 22 of 38 6 Compliance with Critical Area Regulations for Buffer Alterations To Critical Areas RMC 4 -3- 050J.4 This Letter Report asks the City to confirm the following: 1. Pond B, Feature D, and Feature G are not subject to the City’s critical area regulations pursuant to RMC 4-3-050B.1; 2. Wetland A is a Category II wetland with moderate habitat scores; and 3. Field 1 and GK Field (as identified in Figure 4) are low intensity uses pursuant to RMC 4-3- 050G.2, note 7 and RMC 4-11-120.7 Therefore, the appropriate buffer for these uses is 100 feet. Thus, the proposal will require buffer alteration to Wetland A as depicted in Figure 4. There will be no alteration to Wetland A itself. A subsequent Critical Areas Report and Conceptual Mitigation Plan (“Mitigation Report”) will identify compensatory mitigation in greater detail. The Mitigation Report will propose mitigation that considers a variety of available compensatory mitigation methods for wetland buffer impacts. Available mitigation methods may include on-site wetland buffer enhancement at a 1:1 ratio (authorized per RMC 4-3-040J.4.d); the purchase of credits from an approved Mitigation Bank; employing the Wetlands as Buffers concept from the Ecology Wetlands Mitigation Handbook (Ecology Publication 06-06-011a, as updated by Publication 21-06- 003); other methods that are determined to appropriately safeguard applicable wetland functions and values; or a combination of the above. The determination of whether the soccer pitches and GK Field are low intensity land uses will govern applicable buffer widths and may influence the mitigation proposal. Mitigation for any encroachment from the parking component of the proposal will be calculated using the standard 150-foot buffer width, and if the pitches and field are determined to be low intensity land uses a hybrid buffer may be proposed as depicted in Figure 4. Should you have any questions or require additional information at this time, please feel free to contact Jacob Prater or me at (425) 861-7550. Thank you. Sincerely, TALASAEA CONSULTANTS, INC. William E. Shiels Principal 7 Footnote 2 of this Letter Report describes the use of Field 1 and the GK Field.