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Home My WebLink AboutC_ERC_Determination_Applicant_Letter_180824.pdf Enclosure cc: Gerald Smith / Owner(s) Yoshio Piediscalzi / Engineer Richard Claypole, John Ching / Party(ies) of Record August 24, 2018 Jamie Waltier Harbour Homes, LLC 1441 N 34th St, Ste 300 Seattle, WA 98103 SUBJECT: ENVIRONMENTAL (SEPA) THRESHOLD DETERMINATION Cedars at the Highlands, LUA17-000189 Dear Mr. Waltier: This letter is written on behalf of the Environmental Review Committee (ERC) to advise you that they have completed their review of the subject project and have issued a threshold Determination of Non - Significance-Mitigated with Mitigation Measures. Please refer to the enclosed ERC Report, for a list of the Mitigation Measures. Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on September 7, 2018, together with the required fee with: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Appeals to the Examiner are governed by RMC 4-8-110 and information regarding the appeal process may be obtained from the City Clerk’s Office, (425) 430 -6510. Also, a public hearing has been scheduled by the Hearing Examiner in the Council Chambers on the seventh floor of City Hall on September 18, 2018 at 11:00 am to consider the Site Plan Review, Condistional Use and Modification. The applicant or representative(s) of the applicant is required to be present at the public hearing. A copy of the staff recommendation will be mailed to you prior to the hearing. If the Environmental Determination is appealed, the appeal will be heard as part of this public hearing. If you have any further questions, please call me at (425) 430-7219. For the Environmental Review Committee, Alex Morganroth Associate Planner DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT SIGNATURES: Gregg Zimmerman, Administrator Public Works Department Date Rick M. Marshall, Administrator Renton Regional Fire Authority Date Kelly Beymer, Administrator Community Services Department Date C.E. Vincent, Administrator Date Department Of Community & Economic Development ENVIRONMENTAL (SEPA) DETERMINATION OF NON-SIGNIFICANCE - MITIGATED (DNS-M) PROJECT NUMBER: LUA17-000189 APPLICANT: Jamie Waltier, Harbour Homes, LLC / jwaltier@harbourhomes.com / 1441 N 34th St, Ste 300, Seattle, WA 98103 PROJECT NAME: Cedars at the Highlands PROJECT DESCRIPTION: The applicant is requesting Preliminary Plat, SEPA Environmental Review, and a Tier II Temporary Use Permit for approval of a 14-lot subdivision. The 4.49 acre site is located at 14120 160th Ave SE (APN 1457500110) within the Residential-4 zoning district. The rectangular shaped parcel would be divided into 14 residential lots, a storm drainage tract, a tree retention tract, and a critical area tract. The 8,361 square feet (sf) drainage tract consists of a stormwater vault located at the southeast corner of the site. The applicant would dedicate 28,777 sf for public right- of-way to serve the new lots. The proposed lots would range in size from 9,002 sf to 16,100 sf with an average lot size of 10,224 sf. The plat would result in a net density of 3.66 du/ac. Access to the site would be gained by extending a residential access road (Road A) from 160th Ave SE through the center of the lot. The site contains a Type Ns Stream in the northeast corner of the site that requires a minimum 50 ft buffer as well as a 15 ft building setback. No areas meeting wetland criteria were found on the site. Soils consist of medium dense to dense silty sand with gravel and stiff silt (ML). The soil density was observed to increase with depth. The west side of the site is relatively flat. However, the east side of the site descends approximately ten feet towards the southeastern property line. The existing shop and barn are proposed to remain as part of the plat construction. There are 284 significant trees on the site and the applicant is proposing to retain 41 original trees. The applicant has submitted an Arborist Report, Critical Areas Study, Technical Information Report, Traffic Impact Analysis, and a Geotechnical Engineering Study with the application. PROJECT LOCATION: 14120 160th Ave SE, Renton WA 98059 LEAD AGENCY: City of Renton Environmental Review Committee Department of Community & Economic Development The City of Renton Environmental Review Committee has determined that it does not have a probable significant adverse impact on the environment. An Environmental Impact Statement (EIS) is not required under RCW 43.21C.030(2)(c). Conditions were imposed as mitigation measures by the Environmental Review Committee under their authority of Section 4-9-070D Renton Municipal Code. These conditions are necessary to mitigate environmental impacts identified during the environmental review process. Because other agencies of jurisdiction may be involved, the lead agency will not act on this proposal for fourteen (14) days. Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on September 7, 2018. Appeals must be filed in writing together with the required fee with: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Appeals to the Examiner are governed by RMC 4-8-110 and more information may be obtained from the Renton City Clerk’s Office, (425) 430-6510. PUBLICATION DATE: August 24, 2018 DATE OF DECISION: August 20, 2018 DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC 8/21/2018 | 3:24 PM PDT 8/20/2018 | 2:13 PM PDT 8/20/2018 | 3:43 PM PDT 8/20/2018 | 3:47 PM PDT DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT ERC REPORT 17-000189 ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC MEETING DATE: August 22, 2017 Project Name: Cedar at the Highlands Preliminary Plat Project Number: LUA17-000189, ECF, PP, MOD, TUP Project Manager: Alex Morganroth, Associate Planner Owner: Gerald C. Smith, 14120 160th Ave SE, Renton, WA 98059 Applicant/Contact: Harbour Homes, LLC, 400 N. 34th ST., Suite 300 Project Location: 14120 160th Ave SE, Renton, WA 98059 Project Summary: The applicant is requesting Preliminary Plat approval and Environmental Threshold Determination (SEPA) for a proposed 13-lot subdivision. The project site is 195,531 square feet (4.49 acres) and is located at 14120 160th Ave SE. The project site is located in the Residential-4 (R-4) zoning designation. The proposed single-family residential lots range in size from 9,000 square feet to 17,565 square feet with an overall proposed density of 3.36 dwellings per acre. The applicant has requested a Temporary Use Permit to allow for two existing outbuildings to remain for a period of five years. The structures are located across proposed Lots 9 and 10. Additional proposed improvements include a 3,195 sq. ft. storm drainage tract (Tract A) in the southeast corner of the site along the unimproved 162nd Ave SE right-of-way (ROW) frontage, a 3,500 sq. ft. tree retention tract (Tract C) along the north property line adjacent to lots 11 and 12, and a 20,246 native growth protection tract (Tract B) in the north-east corner to encompass the proposed 75-foot reduced wetland buffer. The proposed lots would be served by a new public residential access street off of 160th Ave SE and a cul-de-sac would be provided near the eastern end of the property. Proposed lots would be served by sanitary sewer along the new street that would connect to an existing main within 160th Ave SE. Proposed lots would be served by a new water main extending from 160th Ave SE along the new street. Construction of the proposed subdivision infrastructure improvements would result in approximately 5,000 cubic yards of cut and 8,000 cubic yards of fill. A Type Ns stream and Category III wetlands are mapped on the site according to COR maps and a Wetlands Report submitted by the applicant. Slopes on the site generally fall to the southeast across the property at a range of 0-20%. Soils consist of Alderwood gravelly sandy loam (AgC). The applicant has proposed to retain approximately 35 of the 284 significant trees onsite. The applicant has submitted a Technical Information Report, Arborist Report, a Critical Areas Determination and a Geotechnical Engineering Study with the application. Site Area: 195,531 SF (4.49 acres) STAFF RECOMMENDATION: Staff Recommends that the Environmental Review Committee issue a Determination of Non-Significance - Mitigated (DNS-M). 0 DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 2 of 9 ERC REPORT 17-000189 Project Location Map: PART ONE: PROJECT DESCRIPTION / BACKGROUND The applicant is requesting Preliminary Plat approval and Environmental (SEPA) Review for the subdivision of one parcel totaling 4.49-acres located at 14120 160th Ave SE, within the SE ¼ of Section 14, Township 23 North, Range 5 East, in King County, Washington. (Exhibit 2). The specific parcel number is 1457500110. The project site formerly consisted of two associated shops/out-buildings used by the property owner, and open space. The site is proposed to be subdivided into 13 single-family residential lots, associated road and utility improvements, a storm water tract, a tree retention tract, and a natural growth protection tract. The storm water tract would consist of a storm water vault to treat runoff on the eastern side of the site. The subject site is bordered by single-family homes around all sides of the property. Located to the north of the site is SE 136th St, SE 142nd Pl is to the south, 162nd Ave SE is to the east, and 160th Ave SE is to the west. Table 1. Surrounding Land Use and Zoning Location Comprehensive Land Use Zoning Site Residential Low Density (RLD) Residential-4 Dwelling Units Per Net Acre (R-4) North Residential Low Density (RLD) Residential-4 Dwelling Units Per Net Acre (R-4) South Residential Low Density (RLD) Residential-4 Dwelling Units Per Net Acre (R-4) East Residential Low Density (RLD) Residential-4 Dwelling Units Per Net Acre (R-4) West Residential Low Density (RLD) Residential-4 Dwelling Units Per Net Acre (R-4) The 4.49-acre project site is located within the Residential - 4 (R-4) dwelling units per net acre zoning classification. The net density of the project is 3.66 dwelling units per net acre (14 / 3.83 net acres = 3.66 du/acre) and the 14 lots DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 3 of 9 ERC REPORT 17-000189 would range in size from 9,001 square feet to 16,694 square feet with an average lot size of 10,154 square feet (Exhibit 2). The property has two (2) existing out-buildings used by the property for storage. The applicant has submitted a Temporary Use Permit to retain the two existing buildings on proposed Lot 9 and Lot 10 for approximately five years – after which time the lots would be developed with two new single-family homes. Access to the site would be provided via a new road (Road A), near the east-west centerline of the site, which would extend from 160th Ave SE to terminate in a cul-de-sac on the eastern end of the site. The section of 162nd Ave SE ROW bordering the proposed site to the east is currently unimproved. A pedestrian pathway is located in the ROW and extends from SE 144th St to the Liberty Gardens subdivision, north-east of the subject site, and transitions from a pedestrian pathway into a paved roadway. The applicant is proposing a 53-foot wide residential access road for Road A. Road A, measured from centerline of 156th Ave SE to the center of the proposed cul-de-sac, measures approximately 525 feet in length. The proposed subdivision would include frontage improvements on 160th Ave SE to add concrete vertical curb, gutter, sidewalk, and planter strip. The applicant has proposed an internal residential access road with a 53-foot ROW that would include concrete vertical curb, gutter, sidewalk, and planter strip, and would culminate in a cul-de-sac with a 90-foot diameter. The applicant has submitted a street modification request for 162th Ave SE proposing no improvements or ROW dedication due to the presence of critical areas, steep topography, and existing pedestrian trail connecting the Liberty Garden subdivision to SE 144th St. The developed site would provide Basic Water Quality treatment in addition to meeting the City’s Matching Forested Conditions for flow control per the 2017 Renton Surface Water Design Manual (RSWDM). Water quality storm volumes are proposed to be treated with a Contech stormfilter and storm detention vault located in the southwest corner of the site. The property includes 284 significant trees comprised of a mixture of native species. The site generally falls to the southeast across the property at a range of 0-20% with a total fall of approximately 10 feet. Soils consist of Alderwood gravelly sandy loam (AgC). According to the Geotechnical Engineering Study prepared by Earth Solutions NW, LLC (Exhibit 10), the native soils encountered at the test pit locations included four to ten inches of topsoil overlying 0.5 to 11 feet of medium dense silty sand with gravel. The findings were consistent with the makeup of glacial till deposits on the western portion of the site and glaciomarine deposit overlain by glacial outwash in the eastern portion of the site. The geotechnical study found that the proposed residential development is feasible from a geotechnical standpoint. According to the Technical Information Report prepared by D.R. Strong Consulting Engineers, the site possesses a moderate to severe susceptibility to erosion activity. PART TWO: ENVIRONMENTAL REVIEW In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project impacts that are not adequately addressed under existing development standards and environmental regulations. A. Environmental Threshold Recommendation Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials: Issue a DNS-M with a 14-day Appeal Period. B. Mitigation Measures 1. Project construction shall comply with the recommendations found in the submitted geotechnical support prepared by Earthworks NW, dated February 23, 2017. C. Exhibits Exhibit 1 ERC Report Exhibit 2 Cedars at the Highlands Preliminary Plat Plan Exhibit 3 Neighborhood Detail Map Exhibit 4 Topographic Map Exhibit 5 Preliminary Landscaping and Tree Retention Plans (Sheets 1-15) DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 4 of 9 ERC REPORT 17-000189 Exhibit 6 Preliminary Grading Plan Exhibit 7 Preliminary Utility Plan Exhibit 8 Preliminary Drainage Control Plan Exhibit 9 Preliminary Road Profiles Exhibit 10 Geotechnical Engineering Study prepared by Earthworks NW, LLC (dated February 2, 2017) Exhibit 11 Preliminary Technical Information Report prepared DR Strong (dated June 29, 2018) Exhibit 12 Arborist Report prepared by Greenforest Incorporated (dated March 20, 2017). Exhibit 13 Tree Retention Worksheet Exhibit 14 Critical Areas Determination Report prepared by Sewall Wetland Consulting, LLC (dated March 28, 2017) Exhibit 15 Revised Critical Areas Determination Report prepared by Sewall Wetland Consulting (dated October 3, 2017) Exhibit 16 Secondary Review, Wetlands Report prepared by Otak (dated December 6, 2017) Exhibit 17 Technical Memo prepared by Soundview Consultants (dated January 31, 2018) Exhibit 18 Technical Memo 2 prepared by Soundview Consultants (dated April 4, 2018) Exhibit 19 Response Memo prepared by Otak (dated April 16, 2018) Exhibit 20 Wetlands Buffer Mitigation Plan prepared by Soundview Consultants (dated June 20, 2018) Exhibit 21 Traffic Study prepared by TraffEx (dated March 21, 2017) Exhibit 22 Construction Mitigation Description Exhibit 23 Advisory Notes to Applicant D. Environmental Impacts The proposal was circulated and reviewed by various city departments and divisions to determine whether the applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with the proposed development. Staff reviewers have identified that the proposal is likely to have the following probable impacts: 1. Earth Impacts: No geo-hazards are mapped on the site. A Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. (dated February 23, 2017; Exhibit 10) was submitted with the project application. In addition, a Geotechnical Infiltration Evaluation prepared by Earth Solutions NW, LLC (dated July 13, 2017; Exhibit 10) was also submitted. The site topography descends gently from the northwest corner to the southeast corner of the site with an estimated total elevation change of 10 feet across the site. The steepest slope identified by the applicant was approximately 20 percent. The study indicated that conventional spread and continuous footings may be utilized across the site, but additional compaction or replacement with structural fill may be required for areas of loose soil on the western portion of the site. The applicant indicates that the estimated quantities for structural fill onsite would be approximately 5,000 cubic yards of cut and 8,000 cubic yards of fill. This grading would be required for the construction of required plat improvements and new single family residences. Temporary erosion and sedimentation control measures would be implemented during construction including, but not limited to, Best Management Practices (BMPs) such as site preparation and grading during the drier summer and early fall months, installing siltation control fencing around the work areas, installing a temporary sedimentation pond prior to beginning earthwork activities, and establishing a quarry spall construction entrances in accordance with City of Renton requirements (Exhibit 21). In January of 2017, a total of five (5) test pits (TP-1 through TP-5) were excavated across the project site with a trackhoe to approximate depths of 11.5 feet below existing site grades. Topsoil and various organics were encountered within the upper 4 to 10 inches of existing grades at the test pit (TP) locations. Conditions underlying the top soil vary depending on test pit locations. In two of the test pits, fill was observed ranging in thickness from 1.5 to 4 feet (TP-2 and TP-5). During the subsurface exploration tests, groundwater seepage was encountered, with especially heavy seepage at TP-5. The study indicates that shallow perched DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 5 of 9 ERC REPORT 17-000189 groundwater seepage zones should be anticipated within site excavations, particularly during the winter, spring, and early summer months. The report noted that contractors should be prepared to dewater during vault and utility excavations, especially if the work is being completed during the wet season. In the Geotechnical Infiltration Evaluation, Earth Solutions NW LLC evaluated onsite soils for infiltration using the “Pilot Infiltration Testing” at four locations. The Pilot Infiltration Test is an approved infiltration testing procedure per Section C.1.3 of the RSWDM. No infiltration was observed in three out of the four locations. At the fourth location (TP-104, located in the southeast portion of the site) there was limited infiltration however advancing the test pit deeper than the infiltration test depth resulted in an observed confining layer of silt that limits the capacity of the underlying subgrade to infiltrate. The report concluded that the confining soil layer can result in lateral migration of water which can create flooding rated issues on the neighboring properties to the south of the subject site, since they are sited lower in the elevation than the subject property. The report concludes that infiltration of stormwater and low impact development (LID) techniques at the site are infeasible. Per the City of Renton (COR) Maps, the site does not contain landslide hazard potential. According to the geotechnical engineer, the site possesses a low susceptibility to landslide due to shallow site slopes of less than 15%. The provided reports conclude that the construction of the proposed residential development is feasible from a geotechnical standpoint. The proposed residential buildings can be supported on conventional continuous and spread footings bearing on competent native soils, re-compacted native soils, or new structural fill. Based on the soil conditions encountered at the test sites, competent native soils suitable for the support of foundations should be generally encountered at depths of one to three feet below existing grades. Pavement and floor slabs can be similarly supported. The ability to use native soil as structural fill will ultimately depend on its moisture content and the weather conditions at the time of construction. The primary geotechnical considerations submitted in the geotechnical report include foundation support, slab-on-grade subgrade support, installation of vapor barriers, the suitability of using onsite soils as structural fill, and construction of the vault. To mitigate for potential impacts the project proposal could have on the site resulting from project construction, staff recommends as a mitigation measure that the project construction comply with the recommendations found in the submitted geotechnical support prepared by Earthworks NW, dated February 23, 2017 or an update report submitted at a later date. Mitigation Measures: Project construction shall comply with the recommendations found in the submitted geotechnical support prepared by Earthworks NW, dated February 23, 2017 or an update report submitted at a later date. Nexus: SEPA Environmental Review, RMC 4-4-060 Grading, Excavation and Mining Regulations. 2. Water a. Wetlands, Streams, Lakes Impacts: According to the City of Renton COR Maps there are existing wetlands and a Type NS stream on the northeast portion of the site and immediately off-site to the north. A Critical Areas Determination Report prepared by Sewall Wetland Consulting, LLC (dated March 28, 2017; Exhibit 14) with the original application identified the Type NS stream that originates from the parcel to the north, continues across the northeast corner of the subject site, and exits into the unimproved ROW to the east of the site. During review of the report, staff determined that the report did not adequately address the wetlands located to the north (described as Wetlands A in the report) of the project site on parcel #1457500106. These wetlands were identified in a wetlands report completed by the same consultant in 2013 as part of the submittal for Mindy’s Place Short Plat. A revised Critical Areas Study prepared by Sewall (Dated October 3, 2017; Exhibit 15) was submitted at staff’s request. The revised study delineated the off-site wetlands to the north of the site and classified the wetlands as a Category II “depressional” system. The report reiterated the presence of the Type NS stream, requiring a 50 foot buffer, but concluded that no wetlands were located on the project site. After reviewing the new assessment against data in COR maps, staff continued to find inconsistencies between the DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 6 of 9 ERC REPORT 17-000189 two Critical Area Determinations submitted by the applicant and the study completed in 2012 for Mindy’s Place. Inconsistencies were primarily related to the delineation of wetlands on the project site. Although the Sewall studies showed the wetlands ending at the property line, staff was concerned that the linear system likely followed the path of the Type NS stream and continued SE across the project site and unimproved public ROW. In order to resolve the inconsistency issues and obtain accurate information on the wetlands, Otak was hired as a secondary reviewer of the on-site and off-site wetlands. At the City’s request, Otak submitted a new report (Dated December 6, 2017; Exhibit 16) to staff, which contained findings and analysis based on a November 20, 2017 site visit completed by Otak staff. The report conclude d that the original wetlands categorization of “Wetlands A” on the northeast corner of the site in the report submitted by Sewall Wetland Consulting was calculated incorrectly. Otak recommended multiple revisions to the initial determination, including a re-categorization of Wetlands A from a Category II “depressional” to a Category III “depressional” wetlands system with a habitat score of 4, requiring a 100 foot buffer per RMC 4-3-050. Otak also recommended a re-evaluation of the delineation due to the presense of wetlands onto the project site. In early February of 2018, a technical memo prepared by Soundview Consultants on behalf of the applicant was submitted to staff (Dated January 31, 2018; Exhibit 17). The memorandum served as a rebuttal to the report prepared by Otak in December and concluded that the wetlands should be classified as a Category II “sloped” wetlands system with a habitat score of 4, requiring a 50-foot buffer per RMC 4-3-050. After submitting the report, Soundview Consultants requested a site visit in order to discuss some of the issues in- person. On March 14, 2018, representatives from Otak, Soundview Consultants, the City, and Harbour Homes met and walked the site. After the site visit, Soundview Consultants submitted another technical memo reiterating their support for their original determination (Dated April 4, 2018; Exhibit 18). After receipt of the Soundview memo, Otak submitted a final memorandum maintaining their position on the classification (Dated April 16, 2018; Exhibit 19). Based on the classification of Wetlands A as a Category III wetlands system with a moderate habitat score (4), a 100-foot buffer with a 15 foot structure setback is required per RMC 4-3-050. A 50 foot buffer is required for a Type NS stream per RMC 4-3-050. Due to the location of the stream near the center of the wetlands area, the required 100-foot buffer for the wetlands would meet the buffer requirements of both the wetlands and stream (50 feet). The applicant has proposed a reduced buffer of 75 feet over an area of approximately 15,460 sq. ft. RMC 4- 3-050 gives the administrator the ability to authorize a 25% reduction in the wetlands buffer if certain conditions are met. The buffer in its current state is highly disturbed and includes mowed lawn, junk cars and debris, and a significant amount of Himalayan blackberry. The wetlands report includes a mitigation plan that includes the removal of junk cars and debris, the eventual removal of the existing building encroaching on the buffer, and the installation of native plantings (Exhibit 21). The plan identifies the types of species proposed for planting in the buffer, but does not identify the number of each plant. The applicant will need to submit a revised mitigation plan indicating the number and location of each plant species in the wetland buffer, in addition to a phasing plan for project mitigation to be completed after the removal of the barn. Staff anticipates an interim mitigation plan and a final mitigation plan that would completely restore the buffer at a later date after the barn is removed. Temporary impacts to the wetlands buffer are anticipated due to the construction of the vault directly adjacent to the southern edge of the buffer. The applicant will need to submit an updated study prior to construction permit submittal, addressing the temporary impacts and the methods used to mitigate for them. Native plantings proposed for the buffer would include Sitka spruce, Douglas fir, Western red cedar, and a variety of native shrubs and grasses, including but not limited to Red-twig dogwood, Salal, Salmonberry, Western swordfern, Streamside lupine, and Spike bentgrass. The entire buffer area would be placed in a tract (Tract B) with a Native Growth Protection Easement on top of the entire buffer and wetlands area. The mitigation plan report concludes that the wetland hydrology and water quality function would see significant improvements if the plan is implemented. Due to the degraded state of the existing wetland buffer and anticipated environmental lift, staff is supportive of the buffer reduction, provided the restoration work is DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 7 of 9 ERC REPORT 17-000189 completed in accordance with a final approved mitigation plan. Provided the project complies with the Critical Areas regulations staff does not anticipate any impacts to the wetlands. Mitigation Measures: Nexus: Not applicable b. Storm Water Impacts: The applicant submitted a Preliminary Technical Information Report (TIR), prepared by DR Strong (dated June 29, 2018; Exhibit 11). Based on the TIR, the project contains greater than 2,000 sq. ft. of new impervious surface and therefore a Full Drainage Review is required pursuant to the 2017 Renton Surface Water Design Manual (RSWDM). All nine core requirements and six special requirements were addressed in the report. Based on the City’s flow control map, the site falls within the Flow Control Duration Standard matching Forested Site Conditions. The project is subject to Basic Water Quality treatment standards in order to satisfy Core Requirement #8. The applicant has proposed a detention vault on the east side of site. The vault would be sized to the City’s Flow Control Standard Level 3 in order to mitigate potential downstream drainage issues. The project site matches the 100-year peak discharge rate to the pre-developed 100-year peak discharge rate. The project is subject to the on-site BMP requirements found in Core Requirement #9. According to the TIR, full dispersion and full infiltration are not feasible on-site BMPs as the minimum design requirements cannot be met. Development Engineering staff believe that basic dispersion may be a viable BMP for some lots within the development. If feasible, basic dispersion should be implemented to the maximum extent feasible which may be more than 10% of the total lot area. It is anticipated that the City’s currently adopted 2017 City of Renton Surface Water Design Manual would mitigate for any potential surface water impacts that could be generated by the project proposal, therefore no further mitigation is recommended at this time. Mitigation Measures: No further mitigation required. Nexus: Not applicable 3. Trees and Vegetation Impacts: The applicant submitted an Arborist Report prepared by Greenforest Incorporated (dated March 20, 2017). The report noted that the property is covered with a weedy and unmaintained understory with a native tree canopy created by the 284 trees located on the site. Several larger trees are located around the project site, including Western red cedars, Douglas firs, and Bigleaf maples (Exhibit 5). The Arborist Report identified 19 landmark trees, 170 significant trees, 85 dangerous trees, and 10 trees within the critical area buffer on the parcel proposed to be developed (Exhibit 12). Approximately 41 of the identified trees were located within the proposed road network. The minimum tree retention requirement is thirty percent (30%) in the R-4 zone. Therefore, the applicant must retain at least 47 trees. After street and critical area deductions, the applicant is proposing to retain 35 trees, or twelve (12) trees less than the amount required by code. Per RMC 4-4-130, a replacement ratio of 12 inches per tree is required for each tree less than the total required to be retained. All retained trees (i.e., protected trees) would be required to be protected during construction pursuant to RMC 4-4-130. The applicant is proposing to replant the subdivision with 48 three-inch caliper trees for a total of 144 caliper inches. Proposed species of trees include Redmond Linden, Western red-cedar, Princeton Elm, Douglas fir, and variety of trees from the Maple family. According the applicants tree planting, the majority of the proposed onsite replacement trees would be used to meet the frontage landscaping and planter strip requirements and includes street trees, front yard trees, and trees near the storm water vault in Tract A. Per RMC 4-4-130, only up to 50% of trees required pursuant to the landscape code may contribute to the replacement tree requirement. Therefore additional trees totaling at least 72 caliper inches must be added in order to meet the tree replacement requirement of 144 inches. A new plat plan layout was received on August 14, 2018 which relocated the vault and adjusted the lots along the south side of the proposed new Road A. DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 8 of 9 ERC REPORT 17-000189 An updated tree plan was not included in the re-submittal. The updated tree plan will be required to be provided prior to the public hearing and will be reviewed for compliance with the 30% retention standards. The applicant has proposed a 3,500 sq. ft. tree tract (Tract C) to the north of proposed lots 11 and 10. The proposed tract contains two landmark trees and four mature significant trees. Three trees are proposed for retention in the tract including a 58” DBH Western red-cedar, a 31” DBH Western red-cedar, and a 25” DBH Western red-cedar. Three of the six trees were classified by the arborist as dangerous and are proposed for removal. The sixth tree, a 24” DBH Western red-cedar near the eastern edge of the tract is shown as retained in the Arborist Report but is shown as removed in the Tree Retention plan. If healthy, the tree should be retained and the plans should be updated to be consistent. The applicant has proposed to retain all trees in the Critical Area Buffer and install 24 new trees including Sitka spruce, Douglas fir, and Western red cedar. However, due to the update plan received on August 14, 2018, it is anticipated that trees will be removed from the wetland buffer as a result of temporary construction impacts for the installation of the vault. These impacts are required to be mitigated per the City’s critical areas regulations, see section 2.a. Wetlands, Streams, and Lakes, above. An updated planting plan should be submitted and include the exact quantities of each species proposed for the buffer. Where there is insufficient ROW space or no public frontage, street trees are required in the front yard(s). A final detailed landscape plan must be submitted and approved prior to issuance of the street and utility construction permits. Mitigation Measures: No further mitigation required Nexus: Not applicable 4. Transportation Impacts: Primary access to the site would be provided via a new dead-end public street off of 160th Ave SE, as shown in the updated preliminary site plan (Exhibit 2). The new Residential Access Road (Road A) would be approximately 550 feet in length and would terminate at a cul-de-sac on the east side of the property. The applicant is proposing a cross-section that includes a ROW width of 53 feet with 26 feet of pavement, 8 -foot wide landscaped planters, 5-foot wide sidewalks, and 0.5-foot wide curbs. The roadway would provide two (2) 10-foot travel lanes and one (1) 6-foot parking lane. The undergrounding of all utilities is required. 160th Ave SE is classified as a Residential Access Road. The existing ROW width is approximately 60 feet. To meet the City’s complete street standards, RMC 4-6-060, a minimum ROW width of 53 feet for a Residential Access Road is required. In addition to the travel lanes, a Residential Access Road ROW requires 0.5-foot wide curbs, 8-foot wide landscaped planters, and 5-foot wide sidewalks. Street trees, storm drainage improvements and undergrounding of any overhead utility lines along the frontage of the property would be required along the project frontage. No dedication of ROW would be required along the project side of 160th Ave SE. 162nd Ave SE, an improved right-of-way, is located along the east property line and is classified as a Residential Access Road with approximately 60 feet of ROW. The applicant has submitted a street modification request to allow the existing unimproved street and frontage section to remain. According to the applicant, the modification was requested due to the presence of a stream and wetlands in the unimproved right-of-way. The applicant contends that improving the road would significantly impact the critical areas and buffers and therefore negatively impact the environment. TraffEx has calculated that the project would generate a total of 10 new vehicle trips per hour in the AM peak period and 13 new vehicle trips per hour in the PM peak period (Exhibit 21). The City does not require Traffic Impact Analyses for developments if both new AM and PM peak period vehicle trips are less than 20. Adequate sight distance would be provided at the intersection of the proposed new street and 160th Ave SE. It is not anticipated that the proposed project would adversely impact the City of Renton’s street system subject to the payment of code-required impact fees and the construction of code-required frontage improvements (Exhibit 23). The fee, as determined by the Renton Municipal Code at the time of building permit issuance shall be payable to the City. DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC City of Renton Department of Community & Economic Development Environmental Review Committee Report CEDARS AT THE HIGHLANDS PRELIMINARY PLAT LUA17-000189, ECF, PP, MOD Report of August 20, 2018 Page 9 of 9 ERC REPORT 17-000189 A concurrency recommendation will be provided in the staff report to the Hearing Examiner based upon the test of the citywide Transportation Plan, consideration of growth levels included in the LOS‐tested Transportation Plan, payment of a Transportation Mitigation Fee, and an application of site specific mitigation. The development will have to meet the City of Renton concurrency requirements. Mitigation Measures: No further mitigation required. Nexus: Not applicable 2. Fire & Police Impacts: Police and Fire Prevention staff indicated that sufficient resources exist to furnish services to the proposed development subject to the construction of code-required improvements and the payment of code- required impact fees (Exhibit 23). Mitigation Measures: No further mitigation required. Nexus: Not applicable E. Comments of Reviewing Departments The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments have been incorporated into the text of this report and/or listed under Exhibit 22 “Advisory Notes to Applicant.” Copies of all Review Comments are contained in the Official File and may be attached to this report. The Environmental Determination decision will become final if the decision is not appealed within the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Environmental Determination Appeal Process: Appeals of the environmental determination must be filed in writing together with the required fee to: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057, on or before 5:00 p.m. on September 7, 2017. RMC 4-8-110 governs appeals to the Hearing Examiner and additional information regarding the appeal process may be obtained from the City Clerk’s Office, Renton City Hall – 7th Floor, (425) 430-6510. DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC CITY OF RENTON DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT STAFF REPORT TO THE ENVIRONMENTAL REVIEW COMMITTEE EXHIBITS Project Name: Cedars at the Highlands Preliminary Plat Project Number: LUA17-000189, ECF, PP, MOD Date of Meeting August 20, 2018 Staff Contact Alex Morganroth Associate Planner Project Contact/Applicant Gerald C. Smith 14120 160th Ave SE Renton, WA 98059 Project Location 14120 160th Ave SE, Renton, WA 98059 The following exhibits are included with the ERC Report: Exhibit 1: Environmental Review Committee (ERC) Report Exhibit 2: Cedars at the Highlands Preliminary Plat Plan Exhibit 3: Neighborhood Detail Map Exhibit 4: Topographic Map Exhibit 5: Preliminary Landscaping Plans and Tree Retention Plans (Sheets 1-15) Exhibit 6: Preliminary Grading Plan Exhibit 7: Preliminary Utility Plan Exhibit 8: Preliminary Drainage Control Plan Exhibit 9: Preliminary Road Profiles Exhibit 10: Geotechnical Engineering Study prepared by Earthworks NW, LLC (dated February 2, 2017) Exhibit 11: Preliminary Technical Information Report prepared DR Strong (dated June 29, 2018) Exhibit 12: Arborist Report prepared by Greenforest Incorporated (dated March 20, 2017). Exhibit 13: Tree Retention Worksheet Exhibit 14: Critical Areas Determination Report prepared by Sewall Wetland Consulting, LLC (dated March 28, 2017) Exhibit 15: Revised Critical Areas Determination Report prepared by Sewall Wetland Consulting (dated October 3, 2017) Exhibit 16: Secondary Review, Wetlands Report prepared by Otak (dated December 6, 2017) Exhibit 17: Technical Memo prepared by Soundview Consultants (dated January 31, 2018) Exhibit 18: Technical Memo 2 prepared by Soundview Consultants (dated April 4, 2018) Exhibit 19: Response Memo prepared by Otak (dated April 16, 2018) Exhibit 20: Wetlands Buffer Mitigation Plan prepared by Soundview Consultants (dated June 20, 2018) Exhibit 21: Traffic Study prepared by TraffEx (dated March 21, 2017) Exhibit 22: Construction Mitigation Description Exhibit 23: Advisory Notes to Applicant DocuSign Envelope ID: DA5EE113-EBEA-486A-A176-507A6F80B5DC 0GRAPHIC SCALE1002004001 INCH = 200 FT.CEDARS AT THE HIGHLANDS14120 160TH AVENUE SERENTON, WASHINGTON 98056CEDARS AT THE HIGHLANDS CEDARS AT THE HIGHLANDS AAANNNNNNN LUA:U:DRS PROJECT NO. 16041A-NNNNNNNNSERISSEFORPINGOERDETSREENGINELA53232 OIETATHSOYSFOTGNIHASWIDEIPL.OCILAZNEIGHBORHOOD DETAIL MAP CEDARS AT THE HIGHLANDS14120 160TH AVENUE SERENTON, WASHINGTON 98059CEDARS AT THE HIGHLANDS CEDARS AT THE HIGHLANDS AAANNNNNNN LUA:U:DRS PROJECT NO. 16041A-NNNNNNNNSERISSEFORPINGOERDETSREENGINELA53232 OIETATHSOYSFOTGNIHASWIDEIPL.OCILAZPRELIMINARY PLAT0GRAPHIC SCALE20'40'80'1 INCH = 40 FT. CEDARS AT THE HIGHLANDS 14120 160TH AVENUE SE RENTON, WASHINGTON 98059 CEDARS AT THE HIGHLANDSCEDARS AT THE HIGHLANDSAAANNNNNNNLUA17-000189U:DRS PROJECT NO. 16041 A-NNNNNNN NSER ISS E FORP I N G O E R DETS REE N G INELA 53232 OIETATHSOY SF OT G NIHASWIDEIPL.O C ILAZPRELIMINARY PLAT 0 GRAPHIC SCALE 15'30'60' 1 INCH = 30 FT. CEDARS AT THE HIGHLANDS 14120 160TH AVENUE SE RENTON, WASHINGTON 98059 CEDARS AT THE HIGHLANDSCEDARS AT THE HIGHLANDSAAANNNNNNNLUA17-000189U:DRS PROJECT NO. 16041 A-NNNNNNN NSER ISS E FORP I N G O E R DETS REE N G INELA 53232 OIETATHSOY SF OT G NIHASWIDEIPL.O C ILAZPRELIMINARY PLAT 0 GRAPHIC SCALE 15'30'60' 1 INCH = 30 FT. CEDARS AT THE HIGHLANDS 14120 160TH AVENUE SE RENTON, WASHINGTON 98059 CEDARS AT THE HIGHLANDSCEDARS AT THE HIGHLANDSAAANNNNNNNLUA17-000189U:DRS PROJECT NO. 16041 A-NNNNNNN NSER ISS E FORP I N G O E R DETS REE N G INELA 53232 OIETATHSOY SF OT G NIHASWIDEIPL.O C ILAZPRELIMINARY PLAT 0 GRAPHIC SCALE 15'30'60' 1 INCH = 30 FT. CEDARS AT THE HIGHLANDS14120 160TH AVENUE SERENTON, WASHINGTON 98059CEDARS AT THE HIGHLANDS CEDARS AT THE HIGHLANDS AAANNNNNNN LUA:U:DRS PROJECT NO. 16041A-NNNNNNNNSERISSEFORPINGOERDETSREENGINELA53232 OIETATHSOYSFOTGNIHASWIDEIPL.OCILAZPRELIMINARY PLAT00HORIZONTALVERTICAL1020401 INCH = 20 FT.2.55101 INCH = 5 FT. EarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineering Geology Environmental Scientists Construction Monitoring 1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY CEDARS AT THE HIGHLANDS 14120 -160th AVENUE SOUTHEAST RENTON,WASHINGTON ES-5048 2018 D. R. STRONG Consulting Engineers Inc. Cedars at the Highlands Technical Information Report Renton, Washington TECHNICAL INFORMATION REPORT for CEDARS AT THE HIGHLANDS PRELIMINARY PLAT 14120 160th Avenue SE, Renton, Washington ___ ____________________________________________________________________________ DRS Project No. 16041 Renton File No. PRE16-000524 Applicant Jamie Walter Harbour Homes, LLC 400 North 34th Street, Suite 300 Seattle, WA 98103 Report Prepared by D. R. STRONG Consulting Engineers, Inc. 620 7th Avenue Kirkland, WA 98033 (425) 827-3063 Report Issue Date June 29, 2018 Greenforest Incorporated C o n s u l t i n g A r b o r i s t 4547 South Lucile Street, Seattle, WA 98118 Tel. 206-723-0656 TO: Chris Burrus Harbour Homes, LLC 1441 North 34th Street, Suite 200 Seattle WA 98103 REFERENCE: Arborist Report, Cedars at the Highlands SITE ADDRESS: 14120 160th Ave SE, Renton, WA 98059 DATE: March 20, 2017 PREPARED BY: Favero Greenforest, ISA Certified Arborist # PN -0143A ISA Tree Risk Assessment Qualified ASCA Registered Consulting Arborist® #379 You contacted me and contracted my services as a consulting arborist. My assignment is to inspect and assess the regulated trees at the above referenced site. I received a topographic survey from DR Strong, and I visited the site 2/10/2017 and inspected the trees, which are the subject of this report. The following table summarizes the tree quantities and categories inventoried in this report. Significant, Landmark and Dangerous categories are defined by municipal code. Landmark Trees On Site 19 Significant Trees On Site 170 Dangerous Trees On Site 85 Trees Within Sensitive Area 10 Total Trees On Site 284 Other Offsite Trees 24 DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT TREE RETENTION WORKSHEET Planning Division 1055 South Grady Way-Renton, WA 98057 Phone: 425-430-7200 | www.rentonwa.gov 1.Total number of trees over 6” diameter 1, or alder or cottonwood trees at least 8” in diameter on project site trees 2.Deductions: Certain trees are excluded from the retention calculation: Trees that are dangerous 2 trees Trees in proposed public streets trees Trees in proposed private access easements/tracts trees Trees in critical areas3 and buffers trees Total number of excluded trees: trees 3.Subtract line 2 from line 1:trees 4.Next, to determine the number of trees that must be retained 4, multiply line 3 by: 0.3 in zones RC, R-1, R-4, R-6 or R-8 0.2 in all other residential zones 0.1 in all commercial and industrial zones trees 5.List the number of 6” in diameter, or alder or cottonwood trees over 8” in diameter that you are proposing5 to retain4:trees 6.Subtract line 5 from line 4 for trees to be replaced: (if line 6 is zero or less, stop here. No replacement trees are required) trees 7.Multiply line 6 by 12” for number of required replacement inches:inches 8.Proposed size of trees to meet additional planting requirement: (Minimum 2” caliper trees required for replacement, otherwise enter 0)inches per tree 9.Divide line 7 by line 8 for number of replacement trees 6: (If remainder is .5 or greater, round up to the next whole number) trees 1 Measured at 4.5’ above grade. 2 A tree certified, in a written report, as dead, terminally diseased, damaged, or otherwise dangerous to persons or property by a licensed landscape architect, or certified arborist, and approved by the City. 3 Critical areas, such as wetlands, streams, floodplains and protected slopes, are defined in RMC 4-3-050. 4 Count only those trees to be retained outside of critical areas and buffers. 5 The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-130H7a. 6 When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper or an evergreen at least six feet (6') tall, shall be planted. See RMC 4-4-130.H.1.e.(ii) for prohibited types of replacement trees. 1 H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Tree Retention Worksheet.docx 08/2015 Minimum Tree Density A minimum tree density shall be maintained on each residentially zoned lot (exempting single-family dwellings in R-10 and R-14). The tree density may consist of existing trees, replacement trees, or a combination. Detached single-family development 7: Two (2) significant trees 8 for every five thousand (5,000) sq. ft. of lot area. For example, a lot with 9,600 square feet and a detached single-family house is required to have four (4) significant trees or their equivalent in caliper inches (one or more trees with a combined diameter of 24”). This is determined with the following formula: Multi-family development (attached dwellings): Four (4) significant trees8 for every five thousand (5,000) sq. ft. of lot area. Example Tree Density Table: Lot Lot size Min significant trees required New Trees Retained Trees Compliant 1 5,000 2 2 @ 2” caliper 0 Yes 2 10,000 4 0 1 tree (24 caliper inches) Yes 3 15,000 6 2 @ 2” caliper 1 Maple – 15 caliper inches 1 Fir – 9 caliper inches. Yes 7 Lots developed with detached dwellings in the R-10 and R-14 zoned are exempt from maintaining a minimum number of significant trees onsite, however they are not exempt from the annual tree removal limits. 8 Or the gross equivalent of caliper inches provided by one (1) or more trees. 2 H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Tree Retention Worksheet.docx 08/2015 March 28, 2017 Jamie Waltier Harbour Homes 400 North 34th Street, Suite 300 Seattle, WA 98103 RE: Critical Areas Study – “Cedars at the Highlands” Parcel #45750- 0106 City of Renton, Washington SWC Job#16-152 1.0 INTRODUCTION This report describes our observations jurisdictional wetlands on or within 100’ of the 4.50 acre property known as “Cedars at the Highlands” (Parcel #145750-0110), located off 160th Avenue SE, in the City of Renton, Washington (the “site”). Above: Vicinity Map Sewall Wetland Consulting, Inc. PO Box 880 Phone: 253-859-0515 Fall City, WA 98024 October 3, 2017 Jamie Waltier Harbour Homes 400 North 34th Street, Suite 300 Seattle, WA 98103 RE: Revised Critical Areas Study – “Cedars at the Highlands” Parcel #45750-0106 City of Renton, Washington SWC Job#16-152 1.0 INTRODUCTION This report describes our observations jurisdictional wetlands on or within 100’ of the 4.50 acre property known as “Cedars at the Highlands” (Parcel #145750-0110), located off 160th Avenue SE, in the City of Renton, Washington (the “site”). Above: Vicinity Map Sewall Wetland Consulting, Inc. PO Box 880 Phone: 253-859-0515 Fall City, WA 98024 Technical Memorandum 11241Willows Road NE Suite 200 Redmond, WA 98052 Phone (425) 822-4446 Fax (425) 827-9577 At the request of the City of Renton (City), Otak, Inc. (Otak) conducted a review of the Revised Critical Areas Study – “Cedars at the Highlands”, dated October 3, 2017, prepared by Sewall Wetland Consulting, Inc., for the proposed 14-lot preliminary plat on parcel #1457500110. The project site is located east of 160th Avenue SE in the City of Renton, King County, Washington. The City requested that Otak review the delineation and classification of wetlands, streams, and buffers as described in the report to evaluate compliance with the City of Renton Municipal Code (RMC) Chapter 4-3-050 (Critical Areas Regulations). Otak completed a site visit and critical areas review of the property on November 20, 2017. Weather was overcast and raining, and the stream delineated in the northeast corner of the property was flowing. Large areas of standing water were observed in the northwest corner of the property, and water from a roadside ditch on the east side of 160th Avenue SE was observed flowing into an underground pipe system that is aligned through the center of the property and discharges in the southeast corner of the property. Documents Reviewed The following materials were submitted by the project proponent and reviewed by Otak:  Revised Critical Areas Study – “Cedars at the Highlands” Parcel #45750-0106, prepared by Sewall Wetland Consulting, Inc. (Dated October 3, 2017).  Tentative Short Plat of Mindy’s Place, Conceptual Site Plan, by Daley-Morrow-Poblete, Inc. (DMP, Inc.) (dated November 8, 2012).  Cedars at the Highlands Preliminary Plat, Preliminary Plat Plan 14120 160th Avenue SE, Renton, Washington 98059, prepared by D.R. Strong (DRS) Consulting Engineers (dated March 17, 2017). To: Alex Morganroth, Associate Planner City of Renton From: Jeff Gray, MS, PWS Stephanie Modjeski, Wetland Biologist Copies: Date: December 6, 2017 Subject: Cedars at the Highlands Critical Areas Review Project No.: 32847.B Soundview Consultants LLC January 31, 2018 1155.0024 – Harbour Homes Page 1 2907 Harborview Drive, Suite D Gig Harbor, WA 98335 Technical Memorandum To: Alex Morganroth, Associate Planner From: Don Babineau, Environmental Planner, Soundview Consultants LLC File Number: 1155.0024 Date: January 31, 2018 Re: 14120 160th Ave. SE- Technical Memorandum - Ref. No.: 32847.B Dear Alex Morganroth, Soundview Consultants LLC (SVC) has been assisting Harbour Homes LLC with a response to the third-party review conducted by OTAK, Inc. (OTAK) of the Revised Critical Areas Report written and submitted to the City of Renton by Sewall Wetland Consulting, Inc. (Sewall) regarding the proposed Cedars at the Highlands preliminary plat located at 14120 160th Avenue Southeast in Renton, Washington, 98059 (King County Parcel number 145750-0110). SVC reviewed the Sewall and the OTAK documents and made a brief site visit on December 15, 2017 to preliminarily assess the situation. Upon the initial site visit, SVC shared OTAK’s concerns regarding the area of ponded water in the northwest portion of the site and the additional wetland areas extending from the property to the north onto the site in its northeast corner. Following the initial site visit, SVC conducted a formal wetland and fish and wildlife assessment in early January 2018 and upon encountering signs of fill activity enlisted the use of an excavator to expand the depth of investigation. SVC concurs with OTAK’s general observation of wetland presence in the northwest corner of the subject property but found no type Ns stream on the subject property or on the property to the north. Wetland A is classified as a Palustrine Forested/Shrub Scrub Seasonally Saturated, slope wetland. Using the correct slope hydrogeomorphic class, Wetland A is a Category IV slope wetland. The drainage observed on the property north of the subject property discharging to Wetland A is an excavated ditch. This ditch conveys water from a pipe installed to drain a wetland on the adjacent property north of the Mindy’s Place plat. In addition, this ditch receives water from the Mindy’s Place detention pond outfall prior to draining into Wetland A. A separate manmade drainage crosses the subject property entering at the northwest end and flows to the southeast by a series of drain pipes, upland drainage swales, and areas of sheet flow draining to a ditch and culvert system flowing south from the southeast corner of the property along the east side of an Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 1 2907 Harborview Drive, Suite D Gig Harbor, WA 98335 Technical Memorandum To: Alex Morganroth, Associate Planner File Number: 1155.0024 City of Renton, CED, Planning Division From: Don Babineau, Environmental Planner Date: April 4, 2018 Re: 14120 160th Ave. SE- Technical Memorandum - Ref. No.: 32847.B - follow-up site visit. Dear Alex Morganroth, Thank you for taking the time to meet with our team and OTAK onsite on March 14, 2018. This memorandum is in response to the comments made during the meeting with OTAK regarding the critical areas review for the proposed Cedars at the Highlands preliminary plat located at 14120 160th Avenue Southeast in Renton, Washington, 98059 (King County Parcel number 145750-0110). Non-Wetland Areas and Onsite Southern Drainage Otak and Soundview Consultants LLC (SVC) discussed the ponded areas in the northwest portion of the site which Sewall originally assessed as uplands prior to the recent fill brought onto the site. OTAK agreed that the SVC memo adequately assessed and documented the area as anthropogenically altered as a result of the compacted fill and was not a natural wetland area. As such, it was agreed the area would not be considered a regulated critical area. The culverted drainage through the ponded area draining to the southeast corner of the site was also determined to be a nonregulated manmade feature. Wetland A and Associated Drainage Otak and SVC discussed Wetland A and the associated drainage through the wetland. While the drainage associated with Wetland A does not meet the definition of a stream per City of Renton code as it does not flow to a perennial waterbody via an above ground channel system, because the channel exhibited natural stream like characteristics, it was agreed that the drainage would be treated as a Type Ns stream. While Otak staff agreed with the delineation of Wetland A, they maintained their assessment of the hydrogeomorphic (HGM) classification of the wetland as a depressional wetland. SVC does not concur with this classification. From the onsite inspection, it was clear there is no significant depressional function of the wetland to meet the threshold of being classified as a depressional wetland. While there are obstructions (tree branches and logs) slightly impeding the surface flow of the drainage within the wetland, there are not adequate depressions within the streambed to classify the wetland as depressional. To confirm the lack of depressions within Wetland A, following the site, Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 2 visit SVC conducted a highly precise LIDAR analysis of the topography of the wetland area (see Attachment A). From the analysis it is clear to see the geomorphology of Wetland A resembles a chute with an even gradient along the channel and no depressions or hummocks which would create depressional areas. For a wetland to be depressional, it must impound water. Wetland A does not have the capability to significantly impound water. SVC correctly used the accepted HGM classification system as outlined by Brinson (1993) and in accordance with Section 5.1 and the classification key of the rating form located in Appendix A of the Washington State Wetland Rating System for Western Washington (Hruby, 2014). Otak staff cited a portion of Section 5.1 during the sit visit as justification for classifying Wetland A as depressional and the citation was one sentence taken out of context. He said that according to the manual, slope wetlands do not receive water through surface flow. The following is the full, accurate portion of the manual to which he referred: Slope wetlands with surface flows can be distinguished from Riverine wetlands by the lack of a defined stream bed with banks. Slope wetlands may develop small rivulets along the surface, but they serve only to convey water away from the wetland. There is no surface flow coming into the wetland through channels. This portion of the manual is in regard to distinguishing slope versus riverine wetlands, and it was agreed Wetland A is clearly not a riverine wetland. This portion of the manual has nothing to do with determining if a wetland is depressional. To determine a wetland’s HGM classification, the rapid assessment procedure is to follow the key located in the front of the 2014 rating form which consists of a set of progressive yes/no questions. The first three questions on the key determine if the wetland is either a tidal fringe, flats, or lake fringe wetland and are obviously not applicable. The fourth question deals with slope wetlands and has three criteria required to meet the classification: • The wetland is on a slope, • The water flows through the wetland in one direction and usually come from seeps. It may flow subsurface, as sheet flow or in a swale without distinct banks, • The water leaves the wetland without being impounded. Wetland A has a clear, continuous slope with seasonal main channel flowing through it and a saturated slope edge which feeds into the main channel. Hydrology flows through the wetland in one direction. The wetland receives its hydrology from groundwater and direct precipitation and leaves the wetland without significant impoundment. The second criteria may appear to add some uncertainty but having a stream channel at the lowest point cross-sectionally within a slope wetland is common. Technically, Wetland A is actually two separate wetlands flowing on either side of the stream channel to that channel; however, per the 2014 manual guidance, slope wetlands are to be treated as one wetland when the stream bisecting them is as narrow as Stream Z. From the attached LIDAR exhibit, it is clear to see that most of the wetland area is uphill from the channel running through the wetland. This is an important distinction because it shows the wetland does not receive the majority of its hydrology from the stream. Instead, it contributes to the stream’s hydrology through lateral flow to the central Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 3 stream channel. At times of heavy flow, the stream will encroach on a small portion of the wetland area, but this increased flow is not the main source of wetland hydrology. When the stream stops flowing, Wetland A persists in its hydrated state because groundwater is the wetland’s main source of hydrology. A depressional classification would infer that the wetland has areas of significant impoundment that would allow for stagnation and fallout of particulates. The wetland on the subject property was observed to have micro-depressions that are receiving flow from the main channel, however these micro-depressions were observed to be continuously flowing, highly oxygenated, and not providing the potential for anaerobic conditions. Soil data supports these observations with a lack of obvious hydric soil conditions that would be expected in a depressional wetland. Conclusion Because the Wetland A is properly classified as a slope wetland, it is accurately rated per SVC’s previous assessment as a Category IV wetland which requires a standard 40-foot buffer per Renton Municipal Code (RMC) Title IV, Chapter 3 (4-3-500). Per SVC’s original assessment and the site meeting, this is the only regulated wetland onsite. SVC and Otak agreed the drainage flowing through Wetland A is the only regulated stream feature and should be treated as a Type Ns stream requiring a 50 -foot buffer per RMC Title IV, Chapter 3 (4-3-500). Please contact me with any questions or concerns you may have regarding this matter. Sincerely, April 4, 2018 Don Babineau Date Environmental Planner/Project Manager Soundview Consultants LLC 2907 Harborview Drive, Suite D Gig Harbor, WA 98335 don@soundviewconsultants.com Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 4 References Brinson, M. M., 1993. “A Hydrogeomorphic Classification for Wetlands,” Technical Report WRP DE-4, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. Cowardin, L.M., V. Carter, F. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish & Wildlife Service. Washington D.C. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y- 87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. Federal Geographic Data Committee. 2013. Classification of Wetlands and Deepwater Habitats of the United States. FGDC-STD-004-2013. Second Edition. Wetlands Subcommittee, Federal Geographic Data Committee and U.S. Fish and Wildlife Service, Washington, DC. Hruby, T. 2014. Washington State Wetland Rating System for Western Washington – Revised. Washington State Department of Ecology Publication # 14-06-029. Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 wetland ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X Munsell Color. 2000. Munsell Soil Color Charts. New Windsor, New York. Natural Resources Conservation Service (NRCS). 1995. Hydric Soils of Washington. U.S. Department of Agriculture. Washington D.C. NRCS. 2001. Hydric Soils List: King County, Washington. U.S. Department of Agriculture. Washington D.C. Null, William, Skinner, Gloria, and Leonard, William. 2000. Wetland Functions Characterization Tool for Linear Projects. Washington State Department of Transportation. OTAK, Inc. 2017. Review of Sewall Wetland Consulting, Inc. Critical Areas Report. Redmond, WA. Renton Municipal Code (RMC). 2017. Title IV, Chapter 3 – Environmental Regulations and Overlay Districts. Passed December 11, 2017. Snyder, Dale E., Gale, Philip S., and Pringle, Russell F. 1973. Soil Survey of King County Area, Washington. Soil Conservation Service. U.S. Army Corps of Engineers. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0), ed. J. S. Wakeley, R. W. Lichvar, and C. V. Noble. ERDC/EL TR-10-3. Vicksburg, MS: U.S. Army Engineer Research and Development. Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 5 Attachment A – Lidar Analysis Exhibit CEDARS OF THE HIGHLAND - LIDAR EXHIBIT DATE: JOB: BY: SCALE: VARIES FIGURE NO. 3/16/2018 DLS 1 CEDARS AT THE HIGHLANDS 14120 160TH AVE SE, RENTON, WA 98059 KING COUNTY PARCEL NUMBERS:45750-0106 1155.0024 ! ! ! ! ! !Wetland Centerline Wetland Boundary Elevation in Feet 426.6 - 428.1 425.7 - 426.6 425 - 425.7 424.3 - 425 423.7 - 424.3 423.1 - 423.7 422.5 - 423.1 421.8 - 422.5 421.1 - 421.8 420.3 - 421.1 419.6 - 420.3 418.8 - 419.6 418.1 - 418.8 417.3 - 418.1 416.6 - 417.3 415.9 - 416.6 415.3 - 415.9 414.7 - 415.3 414 - 414.7 413.3 - 414 412.5 - 413.3 411.8 - 412.5 411.2 - 411.8 410.4 - 411.2 409.5 - 410.4 408.7 - 409.5 407.8 - 408.7 407.1 - 407.8 406.5 - 407.1 405.9 - 406.5 405.2 - 405.9 404 - 405.2 Top Elevation 418.5 Feet Bottom Elevation 408 Feet Length of Centerline 316 Feet Wetland A 3.3% Slope ¢ Soundview Consultants LLC April 4, 2018 1155.0024 – Harbour Homes Page 6 Attachment D – Qualifications Don Babineau Environmental Planner/Project Manager Professional Experience: >10 years Don Babineau is an Environmental Planner and Project Manager with a diverse background in urban and commercial forestry, land planning, landscape architecture, stormwater monitoring and civil engineering. Don has experience as a Forester with Washington State Department of Natural Resources stream typing and delineating stream protection zones, as well as implementing Washington State’s Habitat Conservation Plan to foster the creation of old-growth forest characteristics on state trust lands. Don earned a Bachelor of Science degree in Forest Ecosystems Management and a Bachelor of Landscape Architecture degree, both from the University Of Idaho. Don has been formally trained by the Washington State Department of Ecology in the use of the Washington State Wetland Rating System. In addition, he has received formal training in wetland delineation from the Northwest Environmental Training Center and is an experienced certified erosion and sediment control lead (CESCL). He is also a Pierce County qualified Professional Forester. Richard Peel Wetland Scientist Professional Experience: 5 years Richard Peel is a Wetland Scientist with professional experience in wetland ecology, monitoring, and delineation throughout Washington and Oregon. Richard is Washington State trained in conducting wetland delineations, assessing wetland systems, mitigation planning and design, implementation of monitoring programs, mitigation monitoring and reporting. He also has extensive experience in an analytical laboratory using state-of-the-art equipment in bacteriological and chemical analysis of soil and water samples. Richard is a graduate of The Evergreen State College, with dual degrees in Ecology and Economics. He has focused his academic career on ecology, disturbance ecology, chemistry, and the economic impacts of current environmental management. Richard has extensive training and field experience in wetland related disciplines, and has experience in wetlands both east and west of the Cascades. He has been trained by the Washington State Department of Transportation (WSDOT) Wetland Ecology and Monitoring team in the use of the wetland delineation, mitigation, monitoring, and restoration techniques. In addition, he was directed by WSDOT’s Wetland Protection and Preservation Policy to ensure wetlands are preserved and protected whenever possible. This direction ensures no net loss in the quantity or quality of wetlands in the future and minimization of impacts to wetlands in the present. Technical Memorandum 11241Willows Road NE Suite 200 Redmond, WA 98052 Phone (425) 822-4446 Fax (425) 827-9577 At the request of the City of Renton (City), biologists from Otak, Inc. (Otak) met on site on March 14, 2018 with the applicant and their representatives for a follow up meeting regarding critical areas on Parcel #1457500110 in the City of Renton, King County, Washington. The project proponent, Harbour Homes LLC, is proposing a 14-lot preliminary plat on the property. Otak initially conducted a review of the Revised Critical Areas Study – “Cedars at the Highlands”, dated October 3, 2017, prepared by Sewall Wetland Consulting, Inc., for the proposed project, and provided the City with a critical areas review memo (dated December 6, 2017) regarding consistency with the City of Renton Municipal Code (RMC) Chapter 4-3-050 (Critical Areas Regulations). The applicant submitted a technical memorandum prepared by Soundview Consultants LLC, dated January 31, 2018, in response to Otak’s critical areas review memo that requested additional site information and revisions to the critical areas report for the property. The site meeting on March 14, 2018 was arranged to discuss potential wetland areas in the northwest corner of the property west of the outbuildings, watercourses on the property, and the delineation and classification of wetlands previously identified on the northeast corner of the property. Based on discussions from the site meeting on March 14, 2018, Soundview Consultants LLC provided a second technical memorandum dated April 4, 2018. Otak has reviewed the second memo and provides the following response. Otak concurs that wetlands regulated under RMC 4-3-050 are not present in the northwest corner of the property. The applicant submitted sufficient hydrological and soil information to reasonably conclude that the presence of wetland indicators in this portion of the property are artificial in nature and the result of previous activities on site. Otak concurs that the watercourse emanating from the roadside drainage along 160th Ave SE is not regulated under RMC 4-3-050. As stated in Otak’s critical areas review memo from December 6, 2017, the seasonal watercourse that flows through a series of culverts from west to east across the center of the property from 160th Ave SE was intentionally created to discharge stormwater from To: Alex Morganroth, Associate Planner City of Renton From: Jeff Gray, MS, PWS Kevin O’Brien, Senior Ecologist Copies: Date: April 16, 2018 Subject: Cedars at the Highlands Critical Areas Review Project No.: 32847.B RECEIVED 04/16/2018 amorganroth PLANNING DIVISION Page 2 April 16, 2018 2 residential developments along 160th Ave SE, and meets the definition of a non-regulated watercourse under RMC 4-3-050. Otak maintains that the wetland located in the northeast corner of the property is classified as a Category III wetland with a 100-foot buffer as stated in our initial review memo from December 6, 2017. Soundview Consultants states in their April 4, 2018 memo that this wetland should be classified as slope under the 2014 Washington State Wetland Rating System for Western Washington (Hruby 2014). However, this wetland has characteristics of slope, depressional, and riverine characteristics which makes the hydrogeomorphic classification of this wetland difficult. This wetland receives surface water inputs from the seasonal stream upslope and the stormwater discharge just east of the property boundary, and groundwater from seeps along the edges of the ravine in which the wetland is situated. The wetland has shallow ponding throughout much of the area, which is indicative of depressional and riverine wetlands. Wetlands that contain two or more hydrogeomorphic classes, or are difficult to classify under the 2014 Washington State Wetland Rating System for Western Washington, should be rated as depressional since hydrologically complex wetlands tend to always have some features of depressional wetlands (Hruby 2014). References Hruby, T. 2014. Washington State Wetland Rating System for Western Washington: 2014 Update. Publication #14-06-029. Olympia, WA: Washington Department of Ecology. 2907 Harborview Dr., Suite D, Gig Harbor, WA 98335 Phone: (253) 514-8952 Fax: (253) 514-8954 Soundview Consultants LLC June 28, 2018 1155.0024 Cedars at the Highlands – Conceptual Buffer Reduction and Enhancement Plan Page 1 of 13 To: Alex Morganroth, Associate Planner File Number: 1155.0024 From: Don Babineau, Soundview Consultants LLC Date: June 28, 2018 Re: Conceptual Wetland Buffer Reduction and Enhancement Plan 14120 160th Ave SE, Renton, WA 98059 Dear Mr. Morganroth, Soundview Consultants LLC (SVC) has been assisting Harbour Homes (Applicant), a wetland and fish and wildlife assessment for the Cedars at the Highlands preliminary plat application. The property consists of one parcel located in the Southeast ¼ of Section 14, Township 23 North, Range 05 East, W.M. (King County Tax Parcel Number 1457500110). Following assessment review and negotiations with the City of Renton (City) and the City’s environmental consultant (Otak), SVC is assisting the applicant with the preparation of a conceptual wetland buffer reduction and enhancement plan for an approximately 4.16-acre property located in the City of Renton at 14120 160th Ave SE (Figure 1). This wetland buffer reduction and enhancement plan has been prepared to accompany a proposed preliminary plat application on the subject property. This Technical Memorandum has been prepared to document regulatory considerations and planning elements for wetland buffer reduction and enhancement. SVC was hired by the Applicant to assess the subject property and respond to the December 6, 2017 review by the Otak. of an assessment previously conducted by Sewall Wetland Consulting, Inc. dated October 3, 2017. SVC conducted the site assessment in January of 2018 in accordance with Washington State Department of Ecology (WSDOE) methodology, as adopted by the City, and documented the assessment results and response to Otak review comments with a technical memorandum dated January 31, 2018. The results of the SVC assessment identified one Category IV slope wetland located in the northeast portion of the subject property extending offsite to the north and east containing a small seasonal drainage feature bisecting the slope wetland. Following the SVC assessment, a site visit with the Applicant, staff from the City, Otak, and SVC was conducted to review SVC’s results. While Otak concurred with a majority of the results documented in the SVC assessment, Otak did not concur with the slope hydrogeomorphic (HGM) classification of the wetland and has incorrectly added classifications to the wetland having a multiple HGM classes to include slope, riverine and depressional wetland classes through improper interpretation of the approved WSDOE classification methodology as outlined in the Washington State Wetland Rating System for Western Washington (Hruby, 2014). As a result of the incorrect classification, Otak rated the wetland as a Category III wetland requiring a 100-foot standard buffer. The wetland clearly meets the Technical Memorandum March 21, 2017 Harbour Homes, LLC Attn: Chris Burrus 1441 N. 34th Street #200 Seattle, WA 98103 Re: Cedars at the Highlands (formerly the Madison Reserve) Plat – City of Renton Revised Trip Generation Letter Report Dear Mr. Burrus: We are pleased to submit this revised trip generation letter report for the proposed Cedars at the Highlands (formerly the Madison Reserve) Plat consisting of 14 single family homes. The original traffic memo was for 13 lots. The proposed project is located at 14120 160th Ave SE in the City of Renton. Access to the site is via a new site access street to 160th Ave. SE. Per City of Renton guidelines, a Traffic Impact Analysis (TIA) is only required for projects that generate 20 or more trips in either the AM or PM peak hour. PROJECT DESCRIPTION Figure 1 is a vicinity map showing the location of the site and the surrounding street network. Figure 2 is the preliminary site plan of the proposed 14 single family homes. Vehicle access is provided by a new site access street to 160th Ave. SE. The parcel number is 1457500110. One existing home will be removed by this development resulting in a net increase of 13 homes. TRIP GENERATION AND DISTRIBUTION The 13 net single-family units resulting from development of the Madison Reserve Plat are expected to generate the vehicular trips during an average weekday and during the street traffic peak hours as shown below: Time Period Trip Rate Trips per unit Trips Entering Trips Exiting Total Average Weekday 9.52 62 50% 62 50% 124 AM Peak Hour 0.75 2 25% 8 75% 10 PM Peak Hour 1.00 8 63% 5 37% 13 A vehicle trip is defined as a single or one direction vehicle movement with either the origin or destination (exiting or entering) inside the study site. The trip generation is calculated using the average trip rates in the Institute of Transportation Engineers (ITE) Trip Generation, Ninth Edition for Single Family Detached Housing (ITE Land Use Code 210). These trip generation values account for all site trips made by all vehicles for all purposes, including resident, visitor, and service and delivery vehicle trips. SUMMARY AND CONCLUSIONS Since the proposed project generates less than 20 trips in any one hour period, a TIA is not required and no significant adverse impact is created due to traffic generated by the development. If you have any questions, please call 425-522-4118. You may also contact us via e-mail at vince@nwtraffex.com or larry@nwtraffex.com. Very truly yours, Vincent J. Geglia Larry D. Hobbs, P.E. Principal Principal TraffEx TraffEx ProjectSite CedarsattheHighlandsPlat VicinityMap Figure 1 * CedarsattheHighlandsPlat SitePlan Figure 2 Cedars at the Highlands Construction Mitigation Description The following narrative is provided to describe the proposed construction mitigation measures that Harbour Homes, LLC “Harbour Homes” and the to be named general contractor “Contractor” for Stinde will implement throughout the duration of the site development and infrastructure period as well as during building construction. Proposed Construction Dates (Site Work): May 2018-October 2018 Harbour Homes anticipates on beginning clearing and site development work in the spring of 2018 depending on the timing of approvals. Harbour Homes anticipates roughly a 180 day schedule to finalize all grading, storm, sewer, water and first lift of asphalt on the site. The goal will be to have the site completely stabilized by November 1st, 2018 before the winter. Proposed Construction Dates (Building Construction): Harbour Homes plans on beginning construction of a model home in May of 2018 and anticipates starting two homes per month thereafter with an average construction timeline of seven months to complete. Hours & Days of Operation Normal site hours of operation will be in compliance with the allowable working hours in the City of Renton which are as follows: For new single-family residences and non-residential construction, the permitted work hours are 7:00am-8:00pm Monday through Friday, 9:00am-8:00pm Saturday, and no work shall be permitted on Sunday. Proposed Hauling/Transportation Routes The Cedars at the Highlands site is located on 160th Avenue SE, north of SE 144th St. The Contractor anticipates utilizing one haul route to and from SR-169. Heading south on 160th Avenue SE, head west on SE 144th Street, north on 156th Ave SE, south on 154th Pl SE to SR-169 then heading east or west dependin g on the type of material import/export. Measures to Minimize Impacts Harbour Homes and the Contractor will make every effort to minimize the impacts from this project on the surrounding neighbors, the environment and traffic circulation for the immediate area. The Contractor and Harbour Homes’ contact information will be clearly posted at the site and the job trailer to ensure communication and immediate responses to any questions or inquiries from the community. Dust/Mud/Erosion Impacts- The Contractor will implement and maintain the TESC measures approved for the Stinde project at all times. Measures such has water trucks, street sweepers and maintaining perimeter erosion fencing help to mitigate impacts. In addition, regular inspections by the City of Renton and the project’s certified erosion control and sediment lead (to be determined), as well as regular meetings between Harbour Homes and the Contractor to ensure compliance. Traffic/Transportation Impacts- Harbour Homes and the Contractor will secure all necessary Right-of-Way use permits including providing traffic control measures to minimize the impact of the frontage improvements associated with the project. Haul routes and hours will be adhered o and Harbour Homes is attempting to minimize the amou nt of import/export needed on the project through careful design of the finishing grade within the site. Utilizing the on -site material and repurposing wood chips and top soil from the clearing activities minimize the need for ongoing truck and trailer loads. Noise- The Contractor will comply with the allowable working hours in the City of Renton (see above) to minimize the impact to neighbors during the site construction and building construction. DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Page 1 of 6 LUA**-000*** ADVISORY NOTES TO APPLICANT The following notes are supplemental information provided in conjunction with the administrative land use action. Because these notes are provided as information only, they are not subject to the appeal process for the land use action. Planning: (Contact: Name, 425-430-7219, amorganroth@rentonwa.gov) 1. RMC section 4-4-030.C.2 limits haul hours between 8:30 am to 3:30 pm, Monday through Friday unless otherwise approved by the Development Services Division. 2. Commercial, multi-family, new single family and other nonresidential construction activities shall be restricted to the hours between seven o’clock (7:00) a.m. and eight o’clock (8:00) p.m., Monday through Friday. Work on Saturdays shall be restricted to the hours between nine o’clock (9:00) a.m. and eight o’clock (8:00) p.m. No work shall be permitted on Sundays. 3. Within thirty (30) days of completion of grading work, the applicant shall hydroseed or plant an appropriate ground cover over any portion of the site that is graded or cleared of vegetation and where no further construction work will occur within ninety (90) days. Alternative measures such as mulch, sodding, or plastic covering as specified in the current King County Surface Water Management Design Manual as adopted by the City of Renton may be proposed bet ween the dates of November 1st and March 31st of each year. The Development Services Division’s approval of this work is required prior to final inspection and approval of the permit. 4. A National Permit Discharge Elimination System (NPDES) permit is required when more than one acre is being cleared. 5. The applicant will be required to submit a Final Wetlands Mitigation Report and Maintenance and Monitoring proposal. In addition, the applicant will be required to comply with all the code requirements of RMC 4-3-050 Critical Areas. This includes, but is not limited to, placing the critical area within a Native Growth Protection Easement, providing fencing and signage, and providing the City with a site restoration surety device and, later, a maintenance and moni toring surety device. 6. The applicant may not fill, excavate, stack or store any equipment, dispose of any materials, supplies or fluids, operate any equipment, install impervious surfaces, or compact the earth in any way within the area defined by the drip line of any tree to be retained. 7. The applicant shall erect and maintain six foot (6') high chain link temporary construction fencing around the drip lines of all retained trees, or along the perimeter of a stand of retained trees. Placards shall be placed on fencing every fifty feet (50') indicating the words, “NO TRESPASSING – Protected Trees” or on each side of the fencing if less than fifty feet (50'). Site access to individually protected trees or groups of trees shall be fenced and signed. Individual trees shall be fenced on four (4) sides. In addition, the applicant shall provide supervision whenever equipment or trucks are moving near trees. 8. This permit is shall comply with the Bald and Golden Eagle Protection Act. The permitted is responsible for adhering to the U.S. Fish and Wildlife Service National Bald Eagle Management Guidelines (2007) and /or your U.S. Fish and Wildlife Service permit. Development Engineering: (Contact: Name, 425-430-7298, rnair@rentonwa.gov) 1. See Attached Development Engineering Memo dated August 17, 2017 ADVISORY NOTES TO APPLICANT Page 2 of 6 LUA**-000*** Fire Authority: (Contact: Corey Thomas, 425-430-7024, cthomas@rentonwa.gov) Environmental Impact Comments: 1. The fire impact fees are applicable at the rate of $718.56 per single family unit. This fee is paid at building permit issuance. Code Related Comments: 1. The fire flow requirement for a single family home is 1,000 gpm minimum for dwellings up to 3,600 square feet (including garage and basements). If the dwelling exceeds 3,600 square feet, a minimum of 1,500 gpm fire flow would be required. A minimum of one fire hydrant is required within 300 -feet of the proposed buildings and two hydrants if the fire flow goes up to 1,500 gpm. Ther e are no existing hydrants within 300-feet of the proposed homes. Existing 4-inch water main in 160th Ave SE will not provide the minimum required fire flow, new on-site and off-site water mains will be required. A water availability certificate is required from King County Water District 90. Fire sprinkler systems may be required if insufficient fire flow cannot be obtained. 2. Fire department apparatus access roadways are required to be a minim um of 20-feet wide fully paved, with 25-feet inside and 45-feet outside turning radius. Fire access roadways shall be constructed to support a 30-ton vehicle with 75-psi point loading. Access is required within 150-feet of all points on the buildings. An approved cul-de-sac type 90-foot diameter turnaround is required for all dead end streets exceeding 300-feet in length. Building: (Contact: Craig Burnell, 425-430-7290, cburnell@rentonwa.gov) 1. Recommendations of the geotechnical report must be followed as a condition of building permits. ADVISORY NOTES TO APPLICANT Page 3 of 6 LUA**-000*** DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT M E M O R A N D U M DATE: August 17, 2017 TO: Alex Morganroth, Associate Planner FROM: Rohini Nair, Civil Engineer III, Plan Review SUBJECT: Cedars at the Highlands Plat 14120 160th Ave SE LUA17-000189 I have reviewed the preliminary plat application for the above-referenced proposal located at parcel 1457500110 and have the following comments: EXISTING CONDITIONS The site is approximately 4.49 acres in size and is rectangular in shape. The existing site is developed with an existing workshop, one shed and gravel driveway. The site includes: Water Water service is provided by King County Water District 90 (425-255-9600 or www.kcwd90.com). The site is located outside of an Aquifer Protection Area. Sewer Wastewater service is provided by the City of Renton. There is an existing 10-inch wastewater main located in 160th Ave SE (see City plan no. S-3235). There is an existing 8-inch wastewater main located in 162nd Ave SE (see City plan no. S-3613). Storm There is an existing 12-inch stormwater main located in 160th Ave SE. There is an existing stormwater ditch located in 160th Ave SE fronting the subject property. Streets The proposed development fronts 160th Ave SE along the west property line(s). 160th Ave SE is classified as a Residential Access Road. Existing right-of-way (ROW) width is approximately 60 feet. The proposed development fronts 162nd Ave SE along the east property line(s). 162nd Ave SE is classified as a Residential Access Road, and is an unimproved right-of-way. Existing right-of-way (ROW) width is approximately 60 feet. CODE REQUIREMENTS WATER 1. A water availability certificate from King County Water District 90 was provided with the site plan submittal. The water availability certificate noted that a flow rate of 1,500 gallons per minute (gpm) can be provided to the site by an 8” water main extension to the site. 2. Review of the water plans will be conducted by King County Water District 90 and the Renton Regional Fire Authority. ADVISORY NOTES TO APPLICANT Page 4 of 6 LUA**-000*** 3. Plans approved by King County Water District 90 shall be routed to the City for final review prior to permit issuance. SEWER 1. The development is subject to a wastewater system development charge (SDC) fee. The 2018 SDC fee for sewer is based on the size of the new domestic water to serve the project. The current sewer fee for a 1 -inch meter install is $2,837.00 per meter. Each lot shall have a separate meter. The final fee amount is calculated and payable at the time of construction permit issuance. 2. The development is in the Central Plateau Interceptor Special Assessment Districts (SADs). a. The Area SAD fee for the Central Plateau Interceptor SAD is $351.95, plus interest of $0.05111 per day, for each lot. As of 8/7/2018, the total SAD fee is calculated as $519.78 per lot. The final fee amount is calculated and payable at the time of construction permit issuance. b. The Frontage SAD fee for the Central Plateau Interceptor SAD is $5,810.34, plus interest of $0.84369 per day, for each lot with frontage along 160th Ave SE. As of 8/7/2018, the total SAD fee is calculated as $8,581.03 for each lot that has frontage on 160th Ave SE. The final fee amount is calculated and payable at the time of construction permit issuance. 3. The existing sewer main along 160th Avenue SE along with the existing sewer service located on Lot 1 as shown on the composite utility civil plan submitted with the Land Use Application. 4. The proposed sewer main improvements as shown on the composite utility civil plan submitted with the Land Use Application provides the required 8-inch sewer main extension from the existing sewer main located in 162nd Avenue SE and extending west into Cedars at the Highlands for future extension by the City. The required extension of the new 8-inch sewer main from 162nd Avenue SE into the future public ROW is shown on the conceptual utilities plan and provides the required sanitary sewer service to lots accessing off of internal project street except Lot 1 which will utilize the existing sewer service on the lot. The lots accessing from 160th Avenue SE will obtain sanitary sewer service from the existing 8-inch sewer main within 160th Avenue SE. a. A 15-foot public sewer easement is shown A 15-foot public sewer easement shall be provided for the extension of the sewer main through the stormwater tract for any portion of the extension located outside of the public ROW. 5. All new side sewers shall be 6”. All side sewers shall flow by gravity to the main at a minimum slope of 2%. As shown on the preliminary utility plan, each lot shall have its own side sewer. SURFACE WATER 1. The development is subject to a storm water system development charge (SDC) fee. The 2018 SDC fee for storm water is $1,718.00 for each new lot. The final fee amount is calculated and payable at the time of construction permit issuance. 2. A Preliminary Drainage Plan and Technical Information Report (TIR) prepared by DR Strong dated June 29, 2018 were submitted to the City as part of the site plan submittal. The site is located in the City’s Flow Control Duration Standard (Forested Site Conditions). The site is located in the Lower Cedar River drainage basin. The TIR was completed in accordance with the standards found in the 2017 Renton Surface Water Design Manual (RSWDM). All nine core and six special requirements were addressed. A detention vault is proposed to meet the flow control facility requirement to satisfy Core Requirement #3. The detention vault has been sized to the City’s Flood Problem Flow Control Standard (King County Level 3) using WWHM to help mitigate potential downstream drainage issues. The project matches the pre-developed discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow and peak discharge rates for the 2 and 10- year return periods as required in the City’s Flow Control Duration Standard (Forested Site Conditions) area. In addition, the site matches the 100-year peak discharge rate to the pre-developed 100-year peak discharge rate to meet the City’s Flood Problem Flow Control Standard. The project is subject to Basic Water Quality treatment standards to satisfy Core Requirement #8. A stormwater quality vault following the detention vault will be utilized to address this requirement. ADVISORY NOTES TO APPLICANT Page 5 of 6 LUA**-000*** The project is subject to on-site BMP requirements found in Core Requirement #9. Full dispersion and full infiltration are not feasible on-site BMPs as the minimum design requirements cannot be met. Permeable pavement, bioretention, and rain gardens were deemed infeasible per the infiltration testing in the geotechnical report. Limited infiltration is deemed infeasible due to the till soils. Basic dispersion may be feasible. If feasible, basic dispersion should be implemented to the maximum extent feasible which may be more than 10% of the total lot area. Feasibility of on-site BMPs for each lot will be reviewed at the time of single family building permit. The restricted footprint BMP can still be used in addition to receive the 10% lot area modeling credit when sizing the detention vault. Final TIR should clearly explain how target surfaces from plat infrastructure (road and sidewalk) are mitigated by on-site BMPs or how BMPs are infeasible for these surfaces. 3. A geotechnical report evaluating site soil conditions was prepared by Earth Solutions NW LLC dated February 23, 2017 and a Geotechnical Infiltration Evaluation prepared by Earth Solutions NW LLC dated July 13, 2017. The report describes the site’s erosion hazard level as low. The soils on site were described as 4 to 10 inches of organics over medium dense silty sand with gravel and dense poorly graded sand were encountered extending to the maximum exploration depth of 11.5 feet below existing grade. There was approximately 1.0’ to 4.0’ of fill encountered in the northwest portion of the site. Earth Solutions NW LLC evaluated onsite soils for infiltration using the “Pilot Infiltration Testing” at four locations. The Pilot Infiltration Test is an approved infiltration testing procedure per Section C.1.3 of the RSWDM. No infiltration was observed in three out of the four locations. At the fourth location (TP-104, located in the southeast portion of the site) there was limited infiltration however advancing the test pit deeper than the infiltration test depth resulted in an observed confining layer of silt that limits the capacity of the underlying subgrade to infiltrate. It is the geotechnical engineer’s opinion that this confining soil layer can result in lateral migration of water which can create flooding rated issues on the neighboring properties to the south of the subject site since it is sited lower in the elevation than the subject property. 4. The report concludes that infiltration of stormwater and low impact development (LID) techniques at the site are infeasible. 5. There is an existing Unspecified Drainage Conveyance System flowing through the project site that appears to convey upstream tributary from 160th Avenue SE. The Applicant is proposing to capture and convey this upstream flow to the downstream conveyance system via a storm water piped system that will be routed through the future proposed right of way through the project site. The size of the bypass conveyance system shall be determine in accordance with the RSWDM and provided as part of the Civil Construction Permit Application. 6. A Construction Stormwater Permit from Department of Ecology is required if clearing and grading of the site exceeds one acre. TRANSPORTATION 1. Each new lot is subject to a transportation impact fee. The 2018 transportation impact fee is $5,430.85 per single family home. A credit for one lot will be issued due for the existing home. The transportation impact fee is due at the time of building permit issuance for each individual home. 2. The proposed development fronts 160th Ave SE along the west property line(s). 160th Ave SE is classified as a Residential Access Road. Existing right-of-way (ROW) width is approximately 60 feet, which satisfies the RMC 4-6- 060 required minimum required ROW width of 53 feet. No additional right-of-way fronting the site will be required. To provide consistency with the existing pavement width in the corridor adjacent to the project site, a half street paved width of 16 feet, gutter, 0.5 feet wide curb, 8 feet wide landscaped planter, 5 feet wide sidewalk, street trees, storm drainage improvements and undergrounding of any overhead utility lines along the frontage of the property are required on the project frontage. 3. The proposed development fronts 162nd Ave SE along the east property line(s). 162nd Ave SE is classified as a Residential Access Road, and is an unimproved right-of-way. Existing right-of-way (ROW) width is approximately 60 feet, which satisfies the RMC 4-6-060 required minimum required ROW width of 53 feet. Per RMC 4-6-060, a paved half street width of 13 feet, a 0.5-foot curb, an 8-foot planting strip, an 5-foot sidewalk, street trees, storm drainage improvements, and undergrounding of all utilities are required on the project frontage. However, the applicant has submitted a street modification request to allow the existing street and frontage section to remain. ADVISORY NOTES TO APPLICANT Page 6 of 6 LUA**-000*** The modification was requested due to the presence of the stream that runs through the ROW and altering the existing conditions of 162nd Ave SE would impact the stream and the adjacent critical area. Staff supports the requested modification. 4. A dead end public street with 53 feet ROW width and 26 feet wide pavement is proposed for the internal site access. 0.5 feet wide curb, 8 foot wide planters and 5 foot wide sidewalks are proposed on both sides of the internal street. The proposed widths meet the minimum required widths mentioned in RMC 4-6-060. Undergrounding of all utilities is required. 5. Current City of Renton standards require a cul-de-sac turnaround for dead-end streets greater than 300 feet and less than 500 feet. Reference RMC 4-6-060H. a. Cul-de-sacs shall have a minimum paved and landscaped radius of 45 feet with a right-of-way radius of 55 feet for the turnaround. b. The cul-de-sac turnaround shall have a design approved by the Administrator and Fire and Emergency Services. 6. Refer to City code 4-4-080 regarding driveway regulations. a. A minimum separation of 5 feet is required between driveway and the property line. b. Maximum driveway slopes shall not exceed 15%. Driveways exceeding 8% shall provide slotted drains. c. The maximum width of single loaded garage driveway shall not exceed nine feet (9') and double-loaded garage driveway shall not exceed sixteen feet (16'). 7. Street lighting is required from a development that includes more than 4 residential units. A photometric study and street lighting plan per City standard shall be submitted at the time of construction permit review. 8. All ramps and sidewalks shall be designed in accordance with ADA Regulations. 9. Paving and trench restoration within the City of Renton right of way shall comply with the City’s Restoration and Overlay requirements. GENERAL COMMENTS 1. The fees listed are for 2018. The fees that are current at the time of the respective permit issuance will be levied. Please see the City of Renton website for the current fee schedule. 2. Retaining walls that are 4’ or taller from bottom of footing and stormwater detention vaults will require a separate building permit. Structural calculations and plans prepared by a licensed engineer will be required as part of the building permit review. 3. All civil plans shall conform to the current City of Renton survey and drafting standards. Current drafting standards can be found on the City of Renton website. 4. A separate plan submittal will be required for a construction permit for utility work and street improvements. All plans shall be prepared by a licensed Civil Engineer in the State of Washington. 5. Please see the City of Renton Development Engineering website for the Construction Permit Application and Construction Permit Process and Submittal Requirements. Please contact the City to schedule a construction permit intake meeting. 6. All utilities serving the site are required to be undergrounded.