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22-105973-Project Narrative-01-12-23 PROJECT NARRATIVE and CODE CONSISTENCY ANALYSIS for PRELIMINARY PLAT of CREEKWOOD Prepared by: Barghausen Consulting Engineers, Inc. January 12, 2023 PARCEL DATA Parcel No.: 122103-9037 Gross Site Area: ±19.86 acres STR: 12-21N-3E Existing Zoning: RS-15.0 Existing Comprehensive Plan: Single Family Medium Density Fire District: South King County Fire and Rescue School District: Federal Way District No. 210 Water District: Lakehaven Utility District Sewer District: Lakehaven Utility District Thomas Guide Page: 744 Kroll Map Page: 712 SITE DESCRIPTION The site is bordered on the north and south by single-family subdivisions, to the east by a commercial self- storage property, and to the west by vacant residential property. Primary access to the subject property is from the north via the end of 22nd Avenue SW through the adjacent plat of Lakota Ridge. The property also has a second point of access near the northeast corner where 21st Avenue SW transitions to 21st Way SW. The site is undeveloped and vacant with variable downward slopes to the south ranging from gentle to steep. The site contains two localized areas of steep slopes, three wetlands, and four streams. An existing east-west sanitary sewer main and associated easement cross the southern portion of the site. A large diameter 24-inch public stormwater bypass line crosses through the middle of the site from the end of 22nd Avenue SW down to Lakota Creek. This line was installed by the city within a public drainage easement granted by a prior owner in order to mitigate flooding and erosion from the adjacent storm drainage system in the Lakota Ridge plat which was the proximate cause of the steep incised ravine on the site. PROJECT DESCRIPTION / HISTORY OF PRIOR APPLICATIONS The proposed plat of Creekwood will subdivide a 19.86-acre property into 20 single family residential lots as a cluster subdivision under the provisions of FWRC 18.55.040. Access to the proposed lots will be from a new public road to be constructed onsite. The plat will create separate tracts for recreation and passive open space purposes, critical areas, and drainage facilities. The project density will end up being just under 1.0 du/ac due to the physical constraints described above which is roughly half of the allowed density in the RS-15.0 zoning designation. The subject property was initially evaluated for development feasibility purposes in 2014 by Core Design and GeoResources, with a site plan showing 26 residential lots. A pre-application meeting was subsequently held on July 27, 2017 for a subdivision of 20 Lots using “lot-size averaging” (LSA) methodology. A preliminary plat application was subsequently submitted on August 16, 2017 and processed under File No’s 17-103948-SE and 17-103947-SU. 2 of 14 22154.005-Project Narrative.docx A Notice of Complete Application was sent to the applicant on January 17, 2018, along with a list of technical review comments and request for additional information. There were a number of concerns outlined in this letter which included the following: • In order to meet LSA requirements, a number of the Lots were designed to include portions of steep slopes and other critical areas and buffers within the Lot. This concept was not supported by the city due to the obvious conflict between private land ownership and the need to protect and preserve critical areas and buffers. • Trails were proposed within the critical areas and buffers with resulting impacts due to clearing and grading activities associated primarily with a new trail connection from 22nd Avenue SW down the hillside to connect to a future east-west trail that would coincide with the existing vehicular access road maintained by Lakehaven Utility District (LUD) along the alignment of their trunk sewer line adjacent to Lakota Creek. • The site is located within the ASARCO Smelter Plume overlay. Concerns were expressed about the potential for Lead and Arsenic contamination being present on the site above MTCA levels. • Stormwater detention was proposed via an open pond in relatively close proximity to the top of the steep slopes. A variety of concerns were expressed by Public Works as well as by GeoDesign Inc., the city’s 3rd party review consultant. These included concerns for slope stability due to leakage from the storm pond along with potential failure of the pond liner. • The city expressed concerns over the design of the proposed public road crossing over the ravine above the emergent point of Drainage “Y.” These included the useful life of the proposed retaining wall being at least 50 years, and requirements for maintenance. The initial applications were partially reviewed by the city, but Application No. 17-103947-SU subsequently expired on June 14, 2019, when a gap of over 6 months occurred during the review process between resubmittals. A new application was filed on July 8, 2019, to replace the expired one. This new application was substantially in conformance with the 2018 application but included responses to city comments outlined in the city’s previous Notice of Complete Application letter. The new application was given File No. 19- 103218-SU. The city sent comments to the applicant on December 19, 2019, and the applicant responded with resubmittals on January 27, 2020, and October 27, 2020. The final response from the city on the above applications was sent to the applicant on May 25, 2021. While substantial progress had been made addressing many of the earlier concerns and issues raised by the city and their consultant team, there were still outstanding issues to be addressed. At this point the applicant contacted Barghausen Consulting Engineers Inc. (BCE) to assist with responses to the letter of May 25, 2021. However, by the time the response was submitted to the city on April 22, 2022, the application had once again expired, prompting the applicant to once again file for a new pre-application review with city staff on May 20, 2022. The pre-application meeting was held on June 16, 2022, and the project was given new File No. 22-102372-00-PC with a formal response from the city dated July 11, 2022. Although the overall layout of the public road and developable lot areas are similar to what was proposed in prior applications, the new design of Creekwood as a cluster subdivision reflects a number of important and significant changes to the proposed storm drainage system, the design of the ravine crossing, and how the open space is handled. We are confident that this new design will adequately mitigate and/or resolve all of the prior issues and concerns that were outlined in the May 25, 2021 review letter from the city on the prior application. 3 of 14 22154.005-Project Narrative.docx CLEARING AND GRADING As designed, the proposed clearing and grading will be generally limited to the level to moderately sloping areas of the site to minimize the removal of existing trees as well as to minimize the disturbance or compaction of native soils, except as needed for building purposes (road and site development and building pads for the future lots). As a result, the total disturbed area for roads and lots in Creekwood will end up being roughly 30% of the gross land area which is what would be expected just for roads and drainage facilities in a traditional subdivision. This illustrates the significant benefits associated with a cluster subdivision. The Creekwood plat will end up preserving roughly 70% of the total site area as undisturbed open space, thereby also preserving a substantial portion of the existing tree canopy, all critical areas, and the majority of steep slope areas. There is ample justification for clearing and grading the future building Lots concurrent with site clearing and grading for roads, drainage facilities and other infrastructure. A site like this with significant topographic relief requires grading for building lots to accommodate single family homes. A consolidated clearing and grading operation will serve to minimize many of the impacts associated with all land development activities both onsite and offsite related to noise, dust, dirt, and general disturbance to wildlife. If clearing and grading of lots is delayed until the time of homebuilding, the number of truck trips on existing roads will be substantially higher than if the work is consolidated with site development because of inefficiencies associated with multiple mobilizations and the inability to balance earthwork onsite. Impacts associated with noise and dust will extend over a period of several years or more as opposed to a single season. Consolidating the site clearing/grading for roads and lots will result in a fully stabilized site in a much shorter time frame and will ensure that the applicant can effectively install and maintain erosion control measures and secure the site for future home development as market conditions dictate. CRITICAL AREAS The site contains two localized areas of steep slopes, three Category IV wetlands, and four streams . All critical areas and their associated buffers will be preserved in open space tracts except for two limited areas. It is in the public interest to provide an alternative public road/emergency vehicle access to 22nd Avenue SW which is a long dead-end cul-de-sac in the adjoining plat to the north. This can be accomplished by extending a new public road form the existing dead-end through the Creekwood plat out to 21st Avenue SW, which is designated as Road “A” on the Creekwood plat. In order to complete this road connection, Road “A” must be designed to cross over the upper reaches of a ravine that lies north of an emergent stream on the proposed plat known as “Drainage Y”. The ravine is the result of erosion in the upper reaches of the north tributary to Lakota Creek drainage system primarily caused by prior flooding from an old storm pond located in the adjacent subdivision. A 24-inch bypass storm line was constructed within adjacent to the tributary in or around 2005 but the ravine remained. The proposed road crossing has been designed to preserve “Drainage Y” in its existing condition but will require buffer averaging and mitigation of temporary stream buffer impacts. Detailed discussion about the critical areas, buffer averaging and temporary buffer impact mitigation is provided in the Wetland and Fish and Wildlife Habitat Assessment prepared by Soundview Consultants dated December 16, 2022. In addition to temporary stream buffer impacts, the proposed road crossing will involve grading within a limited area of steep slopes. The slopes in this area of the ravine are mainly the result of previous erosion due to flooding associated with the adjoining property prior to installation of the 24-inch storm bypass line. Filling this area of the ravine and replacing these steep slopes with a fully engineered fill and cast in place (CIP) retaining wall will fully mitigate any impacts from the proposed grading activities. There are multiple reports from GeoResources that have been prepared for the Creekwood plat. The most recent report dated December 30, 2022 reflects the current grading plan proposal. There are also prior reports that address the crossing of this ravine which are included with the application, of which the one 4 of 14 22154.005-Project Narrative.docx dated October 23, 2020, is also pertinent. In that report, GeoResources notes that slope stability in the area of the Road “A” crossing will be improved over existing conditions. This conclusion was affirmed by the city’s outside consultant (GeoDesign Inc.) in their third-party review on behalf of the city dated March 4, 2021. RETAINING WALLS Rockeries and modular block walls are proposed for some of the lots to minimize grading and impacts to critical area buffers and trees. All rockeries and walls for the proposed lots comply with FWRC 19.120.120. TREE RETENTION The project demonstrates compliance with tree retention/replacement requirements of 25 tree units per acre in the preliminary plat plan set, see Sheet T-1. Tree retention is estimated to be 163 trees per acre. ROADS/ACCESS/TRAFFIC CONCURRENCY The site abuts the road stub of 22nd Avenue SW and the angle transition of 21st Avenue SW to 21st Way SW. 22nd Avenue SW is currently a long dead-end that terminates at the site's northern boundary. Due to the existing length of 22nd Avenue SW, an extension into the site would require a road deviation/variance due to the length and number of homes using this road. In order to mitigate the need for a road deviation/variance, the applicant is proposing a second connection to 21st Avenue SW shown on the plans as Road “A”. This proposed connection between 22nd Avenue SW and 21st Avenue SW will have the added benefit of eliminating the long dead-end in the plat to the north and provide a much needed second access for the neighborhood to the north which currently has only a single access to 21st Avenue SW to serve close to 100 homes which is 307th Street SW. A second public road connection will enable emergency vehicles to access this existing neighborhood in the event 307th Street is blocked by an accident. Due to physical constraints of the site and the extensive critical areas and their associated buffers, Road “A” must cross the same ravine discussed above in the section on Critical Areas. The area of the crossing will be as close to the north property line as possible so as to minimize the amount of fill required, as well as to avoid directly impacting the emergent point for “Drainage Y”. However, the depth of the ravine at the crossing point is such that it is not possible to utilize a traditional 2H:1V structural fill without encroaching onto the emergent point. Therefore, the applicant is proposing to construct a cast in place (CIP) concrete retaining wall within the proposed new public right-of-way for Proposed Road “A” where it crosses the existing ravine just east of the intersection with 22nd Avenue SW. The wall will be on the south side of Road “A” only. The north side does not require a wall. Federal Way Public Works Standards (PWDS) Section 3.9.10 specifically allows the use of CIP retaining walls for new public road construction and sets forth the design criteria to which a CIP must be designed. Section 1.3.2 also refers to WSDOT standards when designing public road improvements. The proposed CIP wall will be designed to comply with all the criteria set forth in PWDS 3.9.10 as well as WSDOT standards. In addition, the applicant sent the proposed CIP wall concept to both a structural engineer as well as a geotechnical engineer to assess the anticipated structural integrity, useful life, and lack of maintenance or defect issues associated with this type of CIP wall. Both consultants concluded that the CIP wall, if designed and constructed properly, should be maintenance free for its useful life. Please see enclosed memorandums from GeoResources and Site Structures summarizing these conclusions. Traffic Concurrency review will occur with the preliminary plat. 5 of 14 22154.005-Project Narrative.docx SCHOOL WALKING CONDITIONS We have reviewed the walk and bus routes for Federal Way Schools per their transportation program. Please see the enclosed School Walking Conditions Exhibit. 1. Elementary School students would walk to Adelaide Elementary School. 2. Junior High School students would walk to SW 304th Street at 17th Avenue SW to be bussed to Lakota Junior High School. 3. High School students would walk to SW 304th Street at Adelaide Load Zone to be bussed to Decatur High School. STORMWATER The site is located in the Lower Puget Sound Basin which is subject to Conservation Flow Control and Enhanced Basic Water Quality. Project-generated stormwater will be collected and conveyed to an underground cast-in-place stormwater detention vault in the north central area of the site (Tract B). Discharge of treated and detained stormwater will be released to the aforementioned existing 24-inch storm bypass pipe in Tract D that outlets directly to Stream Z before leaving the site. The vault will be designed per the 2021 King County Surface Water Design Manual. Although CIP vaults are typically only allowed on private projects inside the City Core, Section 4.1 of the March 2019 Public Works Development Standards (PWDS) of the City of Federal Way allow the Public Works Director to approve the use of a CIP storm vault outside the City Core. In this case there is ample justification for using a CIP vault in lieu of an open stormwater pond, all of which is further outlined in an Administrative Determination (AD) which is included with this application. The AD includes proposed mitigation for the costs of maintenance of a CIP vault vs. an open stormwater pond if it is determined the costs are higher. The AD also summarizes a number of distinct advantages of using a CIP vault vs. an open pond in terms of long-term stability, reduced adverse visual impacts, and elimination of potential noxious odors and insect infestations. FEDERAL WAY COMPREHENSIVE PLAN CONSISTENCY The clustered Preliminary Plat proposal as designed enables development of the subject property in a manner consistent with the underlying zoning designation and Comprehensive Plan while also preserving trees, open spaces, critical areas and habitats, and improving vehicle and pedestrian mobility between neighborhoods. The following Federal Way Comprehensive Plan Policies support the proposed development. Emphasis added by underlining where applicable. LUP 17 Encourage the development of parks and the preservation of open space in and adjacent to residential areas to provide adequate recreational opportunities and preserve the natural setting of Federal Way. LUP 18 Continue to consider special development techniques (e.g., lot size averaging, cottage housing, accessory dwelling units, townhomes, duplexes, and planned unit developments) in single-family areas provided they result in residential development consistent with the quality and character of existing neighborhoods. LUP 19 Preserve site characteristics that enhance residential development (trees, watercourses, vistas, and similar features) using site planning techniques such as clustering, planned unit developments, and lot size averaging. 6 of 14 22154.005-Project Narrative.docx TP 1.14 Develop and maintain a Layered Network that provides connectivity and recognizes that not all streets provide the same quality of travel experience. Classify streets as Freeway, Principal Arterial, Minor Arterial, Principal Collector, Minor Collector, or Local Street. Ensure that the Layered Network continues to provide for all varieties of street uses including regional mobility and cross-town trips, commuting, shopping, and recreational travel, property and business access, and parking, regardless of mode. TP 2.2 Develop a program to create portions of the non-motorized system through public-private partnerships. TP3.13 Acquire access paths between existing developments, cul-de-sacs, public facilities, business areas, and transit followed by trail construction to improve non-motorized circulation. Require the same for all new developments or redevelopments. TP 3.18 Incorporate environmental factors into transportation decision-making, including attention to human health and safety. TP 4.1 Integrate land use and transportation plan decisions to support the land use vision and plan. TP 4.2 Enhance traffic circulation and access with closer spacing of through streets, where feasible, and limiting the area to be served by a single access point commensurate with planned density. HP 15 As appropriate, reduce minimum lot sizes to allow construction of smaller, detached single-family houses on smaller lots. HP 16 Increase capacity and encourage greater diversity of housing types and costs for both infill and new development through various methods, such as inclusionary zoning, density bonuses, and transfer of development rights, cluster housing, cottage housing, garden housing, duplexes, and low to moderate density housing types. NEP 2 Preserve and restore ecological functions, and enhance natural beauty, by encouraging community development patterns and site planning that maintains and complements natural landforms. NEP 3 Plant suitable native trees and vegetation within degraded stream, wetlands, lake buffers, and steep slopes. NEP 6 Mitigation sequencing steps, which begin with avoiding impacts altogether by not taking certain action or parts of an action, should be applied to all projects where impacts to environmentally critical areas are proposed. NEP 7 Implement and periodically update environmentally critical area regulations consistent with Best Available Science while also taking into consideration the City’s obligation to meet urban-level densities and other requirements under the GMA. NEP 9 The City will continue to encourage utilization of the soil safety program and Model Remedies Guidance for properties impacted by the Tacoma Smelter Plume. NEP 10 The City may continue to require environmental studies by qualified professionals to assess the impact and recommend appropriate mitigation of proposed development on environmentally critical areas and areas that may be contaminated or development that may potentially cause contamination. NEP 37 Continue to enforce erosion control measures for work in or adjacent to stream or lake buffers. NEP 38 Appropriate mitigation for detrimental impacts may be required for construction work within the buffer area associated with a stream or a lake. The City will continue to work in cooperation with the Department of Fish and Wildlife through the Hydraulic Project Approval permit process, as applicable, for 7 of 14 22154.005-Project Narrative.docx development proposals that involve streams and lakes. NEP 82 Encourage minimal modification of trees within environmentally critical areas and their buffers. NEP 83 Encourage preserving forested areas within tracts and Native Growth Protection Easements when subdividing land. NEP 92 Regulate new development to ensure new blocks encourage walkability and maximize connectivity and route choice. Create reasonable block lengths to encourage more walking and physical activity. NEP93 Require the continuation of the street network between adjacent development projects to promote walkability and allow easier access for emergency vehicles. NEP 105 Open space provides important wildlife habitat corridors and should be linked with other designated regional and state open space systems. NEP 106 Preserve and restore habitat connections and tree canopy to link stream corridors, geologically hazardous areas, floodplains, wetlands, and critical habitat sites into a system of habitat corridors. This provides connections for wildlife, supports biodiversity, improves water quality, reduces risks due to flooding and landslides, and supports the City’s adaptation to climate change. CODE CONSISTENCY ANALYSIS CLUSTER SUBDIVISION CRITERIA (18.55 & 18.60) FWRC 18.55.040 The innovative or beneficial overall quality of the proposed development shall be demonstrated by the following criteria: (a) The subdivision provides innovative development, otherwise not allowed, but which promotes the goals of the comprehensive plan for architectural compatibility with single-family housing on adjacent properties. Response: The site is so highly constrained with critical areas that it is imperative to use the cluster subdivision criteria to reach a reasonable lot yield for future housing units as would otherwise be anticipated under the RS-15.0 zone. The proposed reduced lot sizes promote retention of existing critical areas and non-fragmented open space where existing trees can be retained. Innovative development is a subjective term, but the innovative measures employed in this proposal include varying lot sizes and shapes as well as utilization of the site resulting in minimal impacts to wetlands, stream, steep slopes, buffers, and surrounding neighborhoods. Even with the benefit of reducing lots sizes to 7,500 SF as allowed under these criteria for a cluster subdivision, the maximum lot yield for the project will still be just under 50 percent of what would be anticipated under the RS-15.0 zoning designation. However, the lot yield would be substantially less if the cluster provisions are not utilized, further reducing the number of proposed housing units in the city. (b) The subdivision results in 15 percent common open space of which at least 10 percent of the gross land area must be usable on-site open space, which is identified with the development and easily accessible to residents. Response: The total open space set aside within the proposed plat is approximately 74.25 percent of the gross land area which is well over the required 15 percent, so this criterion is easily met. The 10 percent usable open space requirement can also be met as further outlined below. 8 of 14 22154.005-Project Narrative.docx One of the approval criteria for a cluster plat (FWRC 18.55.040(3)(a) is to “promote the goals of the comprehensive plan”. This property is zoned RS-15.0 which would normally result in 35-40 residential single family housing units on this 20-acre parcel. This density is what would have been anticipated in order to meet the long-term housing goals of the city as set forth in the comprehensive plan. If the applicant is required to provide 10 percent of the gross site area as useable open space (roughly 1.98 acres) within the developable area, it would reduce the lot yield from 20 lots to 13 lots which directly conflicts with the goals of the comprehensive plan and adversely impacts the future housing stock in the city. However, since a majority of this open space is encumbered with critical areas and buffers, the developable area is reduced to 5.97 acres (the total area in lots, roads, and useable open space/drainage/park tracts). It seems reasonable to calculate the 10 percent requirement on the gross “developable area” rather than on the entire parcel. Otherwise, it imposes an unreasonable burden on the applicant to provide useable open space for property that is essentially undevelopable. The 10 percent required usable open space associated with the developable area only would be 0.597 acres or about 26,000 square feet. The proposed plat has four separate open space tracts that can be developed for both passive and active useable purposes. The largest (Tract B) is proposed where the CIP stormwater vault will be located which will include active recreational improvements and landscaping. The area of this tract is 20,632 square feet which almost meets the 10 percent threshold by itself. The other three useable open space tracts (D, E, and F) will be graded and landscaped, and are accessible to the homeowners via sidewalks on Road A. These are interspersed throughout the plat adjacent to the open space and will have a bench at each location for residents to enjoy the wildlife and vegetation. The area in the useable open space tracts totals 12,895 square feet. The combined total area in Tracts B, D, E, and F is 33,527 square feet which represents 12.89 percent of the developable area which exceeds the 10 percent required. Notwithstanding the above, if the 10 percent calculation were to be based on the gross site, this can still be met by setting aside another open space tract (Tract G) that will encompass the future east-west public trail system that the city has planned to someday complete along Lakota Creek where the existing sewer access road is located. This future trail will be accessible to all residents of the city and would therefore meet the requirement that it be accessible to the residents of this plat. Please see the table below and Sheet 5 of the Preliminary Plat for the summary of open space areas. OPEN SPACE SUMMARY Open Space Category Tracts Percentage of Gross Land Area Area Usable Private B, D, E, and F 3.88% 33,527 sf Usable Public (Future Nonmotorized Trail) G 6.41% 55,424 sf Constrained C and H 63.49% 549,026 sf Landscape Buffer A 0.48% 4,115 sf Total 74.25% 642,092 sf 9 of 14 22154.005-Project Narrative.docx (c) Native tree retention in accordance with FWRC 19.120.130 et seq. Response: A significant portion of the site will be undeveloped where tree retention will be achieved in critical area tracts. Cluster development is being utilized in order to limit disturbance of sloped areas of the site because it is the best option for development that will result in successful retention of mature tree canopy and native vegetation. (d) Cluster lots immediately adjacent to existing neighborhoods have incorporated design elements through lot size and architecture to be compatible as approved by the community development services director. Response: As designed, no new lots will abut any existing residential lots on neighboring properties. The project improves neighborhood connectivity with the extension of 22nd Avenue SW out to 21st Avenue SW. Open space, drainage, and critical areas tracts comprise the entire north, west, and south boundaries. The creative clustering results in lots that will have rear yards adjacent to open space with no physical or visual relationship or impact to any existing offsite lots. Lot 6, the lot closest to any offsite lot, is separated with a 10-foot landscape area and will be more than 10 feet lower in elevation than the nearest lot in the Plat of Lakota Creek. The physical separation as well as vertical separation ensures that the proposed lots in Creekwood Plat will be compatible with existing neighborhoods. The proposed Cluster Subdivision would allow lots to be reduced to 50 percent of the underlying zone, which in this case is 7,500 square feet except for lots abutting the Lakota Ridge plat to the north, which is zoned RS-9.6, which must be at least 90 percent of the underlying zoning minimum, which would be 8,640 square feet. As no proposed lots abut any adjacent property, the project as designed complies with the minimum clustered lot area of 7,500 square feet. (e) The cluster subdivision will not result in destruction or damage to natural, scenic, or historic features. Response: The applicant is not aware of any existing natural, scenic, or historic features on the site. No destruction of features is proposed. All critical areas will be retained in critical area/open space tracts. The proposal to construct the cast in place (CIP) concrete wall for Road A at the ravine will ensure that the project's impacts are contained within the developed lots and common open space areas to the maximum extent possible. Temporary buffer impacts associated with the road fill across the ravine will be fully mitigated following grading. Fencing will be installed at the critical area tracts to prevent human intrusion into the buffer areas. Cluster development is being utilized in order to limit disturbance of sloped areas of the site because it is the best option for development that will result in successful retention of mature tree canopy and native vegetation. (f) Each dwelling unit shall meet the design standards in the FWRC community design guidelines for cluster subdivisions. Response: Future homes will comply with 19.115.120 Design for cluster residential subdivision lots as required (requirements listed below) to be reviewed at the Building Permit stage. • Garages shall be provided for all residential lots, except if the lot is in a multi-family zone. • Front entryways should be the prominent feature of the home. Attached garages should not compose more than 40 percent of the front facade of the single-family home if the garage doors 10 of 14 22154.005-Project Narrative.docx are flush with the front facade or will be set back a minimum of five feet from the rest of the front facade. Detached garages should also be set back a minimum of five feet from the facade. • If garage access is provided from alleys, the front yard setback can be reduced to 15 feet. • Each dwelling unit shall be intended for owner occupancy. APPLICANT'S RESPONSE TO PREAPPLICATION MAJOR ISSUES AND PRIOR REVIEWS Preapplication Meeting Comments dated July 11, 2022. Outlined below is a summary of the major issues of your project based on the plans and information submitted for preapplication review. These issues can change due to modifications and revisions in the plans. The major issues section is only provided as a means to highlight critical requirements or issues. Please be sure to read the comments made by all departments in the following section of this letter. Planning Division • If the proposal is designed as a cluster subdivision, then additional FWRC cluster plat requirements apply regarding design, open space, etc. Response: Please see Cluster Plat Criteria Analysis in this document. The subject property is zoned RS-15.0. A Cluster Subdivision pursuant to FWRC 18.55.040 would allow lots to be reduced to 50 percent of the underlying zone, which in this case is 7,500 square feet except for lots abutting the Lakota Ridge plat to the north, which is zoned RS-9.6, which must be at least 90 percent of the underlying zoning minimum, which would be 8,640 square feet. The project has no lots abutting any neighboring property or subdivision; therefore, the lot areas comply with the minimum area of 7,500 square feet. • Any exploratory site reconnaissance work requires prior city review and approval. Response: Site reconnaissance work has been completed with city review and approval. • Several environmentally critical areas are present on the site and must be evaluated. Response: Special reports are provided to evaluate streams and wetlands, steep slopes, and the ravine crossing. In addition, an analysis relating to the ASARCO Smelter Plume is provided with the application materials. • Mass clearing and grading of the site is not supported by FWRC. Response: The enclosed plans and application materials include a clearing limits plan and a Clearing and Grading Permit and a Forest Practices Permit so that the Use Process III or IV review can be included in the SEPA, land use review, and public hearing, which will help streamline the future Site Development Review process as well. Due to the existing characteristics of the site, including variable topography, complexity of access, presence of critical areas, stormwater discharge from upstream properties, and other factors, we believe that FWRC 19.120 does support clearing and grading of the lots in conjunction with construction of the road, drainage and utility improvements when considering the significant impacts of clearing and grading the lots in an individual basis at the time of homebuilding, which would be eliminated if done concurrent with the rest of the plat road and infrastructure improvements. 11 of 14 22154.005-Project Narrative.docx Clearing and grading the developable portion of the site at one time will limit the repetitive impacts (noise, traffic, erosion risk, etc.) of construction to nearby properties. Temporary erosion and sedimentation control measures would be installed one time and maintained throughout construction. In all likelihood the bulk of site work for the roads, infrastructure and lots could be completed within one construction season which would be the same if clearing and grading was limited to just the roads and drainage facilities. In that event, clearing and grading activities on the individual lots at the time of building permit could easily extend for another two years, with the associated impacts of heavy equipment on new public roads occurring on a regular basis, as well as noise and other adverse impacts on neighboring properties. This additional truck traffic is likely to be year-round rather than during the dry season, leading to a greater potential for erosion impacts and/or mud on the streets. An even more important consideration is the loss of efficiency associated with site work and grading through the homebuilding phase. In all likelihood, each individual lot would require substantial import or export of soil on an individual basis, which not only extends the duration of such work and the associated impacts from heavy truck traffic, but also results in substantially more volume of soil being moved on public roads. All of these impacts can be avoided by mass-grading the lots at the same time as the roads and infrastructure are completed. Preparing the individual lots for future home construction as part of the initial site development will produce the most balanced grading operation in terms of cut to fill (import/export), significantly reducing the number of truck trips to import/export dirt during homebuilding. In order to mitigate for clearing and grading the individual lots in conjunction with the plat development activities, each lot will be covered with 4- to 6-inches of topsoil over the compacted structural building pad and then hydroseeded and mulched to establish a thick covering of vegetation for erosion control purposes. Once the vegetation is stabilized, individual lots can remain vacant for as long as it takes to build a home without concerns for stormwater runoff. Finally, it should be noted that there have been many plats built in the city that were designed and built using mass clearing/grading procedures. This practice is prevalent throughout the Pacific Northwest due in large part to site topographic constraints and on balance results in far less adverse impacts on the environment, surrounding communities, and public roads. Public Works Development Services Division • AD-Administration determination for the proposed CIP vault is required because the project is outside the City Core. Response: A request for administrative determination is enclosed as a separate document. • AD-Administration determination for the CMP box culvert is required. This concept is proposed instead of a solider pile wall crossing a ravine. Response: This no longer applies as neither a box culvert nor soldier pile wall is proposed. The proposed design of the ravine crossing now incorporates a cast-in-place (CIP) wall within the proposed right-of-way for Road A. Such CIP walls are specifically allowed within future public roads if designed to comply with FWPW standards as well as WSDOT guidelines. The CIP wall in this case complies with both standards so an AD is not required. However, an AD has been submitted as a separate document since it was mentioned in the pre-application meeting notes, along with supporting justification from the structural engineer. 12 of 14 22154.005-Project Narrative.docx • Any storm pipe run at 15% or above require pipe anchors (2021 Surface Water Design Manual - Pipe Anchors) • Response: Compliance with this comment is demonstrated in the preliminary plat plan set, see Sheets 7 and 8. • A new review from Wetland/Fish and Game may be require for the proposed box culvert (if excepted) the last review was in 2017. Response: A box culvert is no longer proposed. The emergent point for Drainage “Y” will remain undisturbed with the proposed design using the CIP wall and a 2H:1V fill slope so additional review by WFDW is not anticipated. Public Works Traffic Division • Transportation Concurrency Management (FWRC 19.90) – A transportation concurrency permit with application fee of $5,451 (11-50 Trips) is required for the proposed project. Response: The concurrency application is enclosed with the submittal package. • Traffic Impact Fees (FWRC 19.91) - Traffic impact fees are required for single family residential dwelling units and will be assessed at building permit stage. The estimated total traffic impact fee is $156,281.37. Response: Noted. • Frontage Improvements (FWRC 19.135.040) – Construct Street frontage improvements and dedicate right-of-way (ROW) for two (2) new streets within the property. Response: The site does not have any real "frontage" to existing streets; however, the on-site streets are designed consistently with city standards. A Right-of-Way Modification is requested (see separate submittal) for two sections of Road A in which the standard cross section would be narrowed in order to reduce the impacts to the stream buffer and steep, erosive slopes. As proposed, the Road A design would also increase the landscape buffer between the new roadway and the residences in Lakota Ridge. Modified Section 1 is for the ravine crossing at the intersection of Road A and 22nd Avenue SW. For Modified Section 1, the applicant proposes a 150-foot-long reduction of the overall roadway width and the elimination of the planter strips on both sides of the road. Modified Section 2 proposes the removal of the planter strip on the north side of Road A from 22nd Avenue SW to 21st Avenue SW. Please refer to the Modification Application File. • Access Management (FWRC 19.135.260) – The development shall meet access management standards. Response: New residential driveways will comply with the access management standards. No driveways are proposed within 25 feet of any intersection. Building Division • A geo report shall be submitted with each building permit application. • Any retaining walls will require third party review which is additional cost to the developer. Response: Noted. 13 of 14 22154.005-Project Narrative.docx CITY COMMENTS FROM PRIOR PLAT APPLICATIONS Reference City of Federal Way File Nos. 19-103218-SU and 17-103948-SE Below are prior issues or comments that are addressed in the revised project as presented in the current application package. Although there were a number of individual comments in the review letter dated May 25, 2021, for the most recent prior plat under File 19-103218-SU, we identified three key issues/concerns about the project's design that seem to be the most critical to getting the necessary support from City staff so that the project can proceed to a public hearing. Most of the comments are linked to these three issues as further discussed below: 1. The first issue is the impact to critical areas and buffers associated with the construction of public utility and trail improvements. In the May 25, 2021, letter, the city suggested it may be appropriate and acceptable to allow the applicant to put all critical areas and buffers into permanent open space tracts with designated easements for future trails and thereby waive the requirement for constructing these trails. Our proposed site plan reflects this concept which should adequately mitigate all these concerns. As currently proposed, the project has two large critical area tracts (Tracts C and H) and one open space tract (Tract G) that encompasses the existing east-west sewer easement and planned future non-motorized trail segment. This approach will preserve and protect all critical areas and buffers to the maximum extent feasible, while ensuring that the city will be able to complete their proposed Lakota Public Trail project within Tract G in the future when funding becomes available. The only permanent impacts will be to a very limited area of steep slopes within the upper reaches of the ravine where Road A will cross it. However, the steep slopes in this area have been destabilized over the years due to unchecked erosion dating back to when the flooding first occurred from the neighboring plat. These slopes are a potential hazard and need to be stabilized to prevent this from happening again. There will not be any permanent impact to wetlands, streams, or buffers. The only impacts will be to the buffer above the emergent point of Drainage “Y” due to the road fill across the ravine, but these will be temporary in nature. Once the road crossing is complete the temporary impacts will be fully mitigated through supplemental plantings and restoration of habitat. 2. The second issue involves the proposed open stormwater pond. There were a number of comments/concerns raised primarily by the structural reviewer about the impacts of the proposed stormwater pond on the hillside. The city’s third-party reviewer (GeoDesign Inc.) suggested that the city consider allowing a cast in place (CIP) storm vault, which we agree is a far better approach. As currently proposed, the drainage plan includes a CIP vault in proposed Tract B, in the same general location as the stormwater pond on the previous project's design. Tract B will be landscaped and improved as a private open space park for the enjoyment of the future residents. Maintenance of the park will be the responsibility of the HOA that will be formed for the Creekwood Plat. We understand the City's preference is to utilize open ponds for stormwater control purposes outside of the City Core, but this situation is uniquely suited for use of a CIP vault for several reasons and will provide a superior long-term solution for the control of stormwater. 14 of 14 22154.005-Project Narrative.docx As noted in the enclosed structural engineering memorandum prepared by Site Structures dated December 8, 2022, a suitably designed CIP vault will fully mitigate all concerns about slope stability. The vault should have a useful life expectancy of at least 100 years which is more than double the useful life of a geomembrane liner for an open pond, not to mention providing a more secure containment facility vs. a pond liner than can easily get penetrated by accident. Maintenance costs for a CIP vault may not be any greater than for a stormwater pond, and even if the costs are marginally higher, the homeowners in the plat can fund the overage through the HOA. 3. The third issue concerns the crossing of the ravine just above the beginning of the unnamed intermittent stream, designated on the enclosed materials as Stream “Y”, or Drainage “Y”. There are numerous comments from the City's consultants as well as the City Public Works Department regarding the potential impacts of the ravine crossing along with concerns about maintenance of the previously proposed soldier pile wall, with a request to provide a 10-foot-wide access road and turnaround to access the bottom of the wall for maintenance purposes. Regardless of whether or not an access road to the bottom of this type of soldier pile wall is necessary for maintenance purposes, or if it’s practical or even feasible to do so considering the adverse impacts that would be associated with building such a road, it seems like the best option is to eliminate the soldier pile wall entirely. Our team spent a lot of time evaluating other potential solutions, including a bridge, an open bottom box or arch culvert, and reinforced slopes with geotextile fabric along with short MSE walls. After considering all other options, we concluded the best solution which offers the longest life span, most stability, and is maintenance free would be to construct a cast in place (CIP) reinforced concrete wall at the location of the Road A ravine crossing. The enclosed structural engineering memorandum prepared by Site Structures dated December 8, 2022, summarizes our findings in support of this concept. The CIP wall will be located within the new public road right-of-way behind and below the sidewalk on the south side. The FWPW standards for public road construction allow the use of a CIP retaining wall in situations like this so long as the wall is designed and constructed to comply with these standards as well as WSDOT requirements so filing an Administrative Determination is not necessarily required as noted above in the responses to the July 11, 2022, pre-application notes. However, as further noted above, we prepared an Administrative Determination Request as part of the Creekwood Plat application materials along with supporting documentation confirming this approach is the best and most feasible option for crossing the ravine. In conjunction with the above AD, we provided details of a recent CIP retaining wall that was approved and constructed in a subdivision in the City of Renton known as Allura at Tiffany Park. That CIP wall had a similar height to what is proposed for Creekwood and was also located just inside the public road right-of-way to avoid filling into an adjacent wetland and buffer, thus confirming that this concept is feasible and in fact preferable in a situation like this.