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HomeMy WebLinkAboutSR_HEX_Report_LUA12-013_120612.pdfDEPARTMENT OF COMh _ _ _ JITY AND ECONOMIC DEVELOPMENT REPORT TO THE HEARING EXAMINER A. SUMMARY AND PURPOSE OF REQUEST: REPORT DATE: June 12, 2012 Project Name: Wilson Park II Owner/Applicant: Robert & Doravin Wilson, 21703 60t Street East, Lake Tapps, WA 98391 Contact: Darrell Offe, P.E.; Offe Engineers, PLLC, 13932 SE 159" Place, Renton, WA 98058 File Number: LUA12-013, ECF, PP, PPUD Project Manager: Jennifer Henning, Current Planning Manager Project Description: The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. The site is zoned Residential -14 du/ac (R-14) & Residential - 1 du/ac (R-1). The site contains 9,783 s.f. of protected slopes (>40%). Proposed density averages 6.4 dwelling units per acre across the site, with 8 lots proposed in the R- 14 area, & 2 lots proposed within the R-1 zone. A Planned Urban Development is proposed in order to modify minimum lots size and development standards for the R-1 and R-14 Zones. Access would be provided from South 55th Street via new street constructed as part of the approved Wilson Park I plat. A small hydrologically isolated, unregulated wetland is located on the western portion of the site. The site contains 82 trees, of which 21 would be removed for the construction of the new street serving Wilson Park #1. Ten (10) trees would be retained, and new trees would be planted including 2 new trees per lot. The project requires Environmental (SEPA) Review, Planned Urban Development PUD) Review, and Preliminary Plat review. Project Location: 698 South 55th Street City of Renton Community acid Econonuc. L. ament Department Report to the Hearing Examiner k111 SON PARI: 11 PLATA, PUD LUA12-013. ECF. PP. PPUD PCiBLIC HEARING DA 7E: Jane 12, 2012 Page 2 of 31 B. HEARING EXHIBITS: Exhibit 1: Neighborhood Map Exhibit 2: PUD/Plat Map (Sheet 1 of 1) Exhibit 3: Aerial Photo with Zoning Exhibit 4: Environmental Review Committee (SEPA) Report Exhibit 5: SEPA Determination Exhibit 6: SEPA Mitigation Measures and Advisory Notes Exhibit 7: Density Work Sheet Exhibit 8: C-30 Administrative Policy/Code Interpretation Exhibit 9: Tree Retention Plan Exhibit 10: Tree Retention Work Sheet Exhibit 11: Landscape Plan (Sheet L 1.1) Exhibit 12: Traffic Impact Analysis Report (Northwest Traffic Experts, 6/23/2009 & 1/25/2012) Exhibit 13: Drainage Utilities Plan Exhibit 14: Public Comment Letter: Witt/Vu/Nguyen/Dang/Duong (April 16, 2012) Exhibit 15: Topography Map Exhibit 16: Aerial Photo with City of Renton Slopes Exhibit 17: Road Profile/Grading Plan Cay of Renton C'ommunio- and Economic IJ xmenl Department Rentn to the Hearing Exanrrner WILSON PARK 11 PLAT & P UD L UA12-413. ECF. PP. PP UD I111;13LIC HEARING DATE June 12, 2012 Page 3 of 31 Exhibit IS: Geotechnical Engineering Study Exhibit 19: Proof of Mailing and Posting Exhibit 20: Wetland Verification for Wilson Park 2 (Altmann Oliver Associates, LLC (3/11/2011) Exhibit 21: Addendum to Technical Information Report Prepared for Wilson Park (LUA09-140) by Baima & Holmberg, Inc, dated May 5, 2009 (Darrell Offe, P.E., February 28, 2012) C. GENERAL INFORMATION: 1. Owner of Record: Robert & Doravin Wilson 2170360 th Street East Lake Tapps, WA 98391 2. Zoning Designation: Residential 1 dwelling units per net acre(R-1) and Residential 14 dwelling units per acre (R-14) 3. Comprehensive Plan Designation: Residential Single Family (RSF) and Residential Low Density (RLD) 4. Existing Site Use: Vacant 5. Neighborhood Characteristics: North: Wilson Park I (undeveloped), R -14/R -1/R-8 zoning; portion of Geneva Park, detached single family homes zoned R-14 East: Single Family Residential, zoned R-8 South: South 55th Street and vacant property zoned R -14/R -1/R-8 West: Single Family Residential, zoned R-14 6. Proposed Orientation: Lots would orient east west along a new street, Road "A" 7. Site Area: 2.15 acres 8. Project Data: Existing Building Area: Not Applicable D. HISTORICAL/BACKGROUND: Action Land Use File No. Ordinance No. Date Annexation N/A Comprehensive Plan LUA08-145 5501 11/25/2009 Zoning LUA08-145 5191 11/25/2009 Wilson Park I Prelim Plat LUA09-140 N/A 8/16/2010 E. PUBLIC SERVICES: 1. Utilities: Water: Provided by Soos Creek Water and Sewer District Sewer: Provided by City of Renton Surface Water/Storm Water: Provided by City of Renton Cir, of Renton Communav and Economic D men? Departmertl Reporl to the Hearing Examiner 4711SON PARK 11 PL,4T& PUD LUA12-013, ECF. PP. PPUD P UBLIC 11LA NU DATE: June 11. 2012 Page 4 of 31 2. Streets: South 55`" Street is a Residential Access Street. 3. Fire Protection: City of Renton Fire Department F. APPLICABLE SECTIONS OF THE RENTON MUNICIPAL CODE: 1. Chapter 2 Land Use Districts Section 4-2-020: Purpose and Intent of Zoning Districts Section 4-2-060: Zoning Use Table Section 4-2-110. Residential Development Standards Section 4-2-115: Residential Design and Open Space Standards 2. Chapter 3 Environmental Regulations and Overlay Districts Section 4-3-050: Critical Areas Regulations Section 4-3-100: Urban Separator Overlay Regulations 3. Chapter 4 Property Development Standards Section 4-4-030: Development Guidelines and Regulations Section 4-4-060: Grading, Excavation and Mining Regulations Section 4-4-070: Landscaping Section 4-4-080: Parking, Loading and Driveway Regulations Section 4-4-130: Tree Retention and Land Clearing Regulations 4. Chapter 6 Streets and Utility Standards Section 4-6-060: Street Standards S. Chapter 7 Subdivision Regulations Section 4-7-050: General Outline of Subdivision, Short Plat and Lot Line Adjustment Procedures Section 4-7-080: Detailed Procedures for Subdivision 5. Chapter 9 Procedures and Review Criteria Section 4-9-150: Planned Urban Development Regulations Section 4-9-250: Variances, Waivers, Modifications, and Alternates 6. Chapter 11 Definitions C Ii IJ.7-1;1417.01rL-119/ [i1E 1. Land Use Element — Residential Single Family 2. Community Design Element 3. Environment Element H. DEPARTMENT ANALYSIS: 1. Project Description/Background The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract (Tract A) for open space. The site is zoned Residential -14 du/ac (R-14) & Residential - 1 du/ac (R-1). The existing underlying parcel is 93,801 square feet in size (2.15 acres) and contains 9,783 square feet of protected slopes (>40%). The R-1 City of Remun Community and Fconumic A meet Departmew _ Report to the ITeQritig F_x miner 1471SON PARK 1.I PLO'& PUD LUA12-013, ECF. PP, PP(,,D PURI.IC HF:ARIN(; DATA. June 12, 2012 Page J of 31 Zone comprises 38,326 square feet (including the steep slope area), and the R-14 portion of the site is 55,474 square feet. Proposed density averages 6.4 dwelling units per acre across the site, with 9 lots proposed in the R-14 area, & 1 lot proposed within the R-1. Site soils consist of glacial till. Grading is proposed for the project such that 820 cubic yards would be cut and 11,200 cubic yards of imported material would be used to fill the site. An underground stormwater vault was previously approved for Wilson Park I to be within the roadway on the subject site. The vault is being revised to accommodate the additional stormwater generated by the proposal. A Planned Urban Development is proposed in order to modify development regulations including minimum lots size within the R-1 Zone to create consistently sized lots for detached single family residential homes. Proposed lots would range in size from 5,560 square feet to 6,778 square feet. A portion of the site is subject to the Talbot Urban Separator Overlay Regulations. That portion of the site zoned R-1 is considered to be within the Urban Separator. Per RMC 4-3-110E2.a.ii, 50% of the area within the Urban Separator must be dedicated as irrevocable open space. The applicant proposes to retain 19,164 square feet, or 50% of the site as open space within Tract A. This tract would also provide for open space and recreation opportunities to serve the public and the residents of both Wilson Park developments. An approximate 350 square foot area would be provided with ornamental landscaping, a pergola or gazebo, and hard surface path. A soft -surface, 3 -foot wide walking path would be provided along the north and east boundaries of Lot 6, and along the east boundary of Lots 7 through 10. The path would wrap around the south boundary of Lot 10 and intersect with the sidewalk on the East side of Road A. Ornamental and native landscape plants are proposed within the tract. Access would be provided from South 55th Street via new street (Road A) constructed as part of the approved Wilson Park I plat. The street was identified as being within an easement across the subject site. With the project, the street would be dedicated and the easement would not be necessary. Street improvements including curb, gutter, 5 -foot sidewalks, an 8 -foot planting strip would be provided along both sides of Road A. This is considered to be a Residential Access street, and parking would be allowed on one side of the street. A small hydrologically isolated, unregulated wetland is located on the western portion of the site Exhibit XX). The site contains 82 trees, of which 21 would be removed for the construction of the new street serving Wilson Park #1. An additional 51 trees would be removed for the project. Ten (10) trees would be retained, and new ornamental and native trees would be planted including two new trees per lot. 2. Environmental Review Pursuant to the City of Renton's Environmental Ordinance and SEPA (RCW 43.21C, 1971 as amended), on May 7, 2012, the Environmental Review Committee issued a Determination of Non -Significance - Mitigated (DNS -M) for the Wilson Park II Plat and Planned Urban Development (Exhibits 4, 5). The DNS -M included 7 mitigation measures (Exhibit 6). A 14 -day appeal period commenced on May 11, 2012 and ended on May 25, 2012. No appeals of the threshold determination have been filed. City of Renton Communin, rind Economic D ment Department Report to the Hearing Examiner WILSON PARK 11 PLAT & PUD L UA 12-013, ECF, PP, PPUD PUBLIC NEARING DATE: June 12, 2012 Page b of 31 3. Compliance with ERC Conditions Based on an analysis of probable impacts from the proposal, the Environmental Review Committee ERC) issued the following mitigation measures with the Determination of Non -Significance — Mitigated: 1. The applicant shall comply with the recommendations contained in the Geotechnical Engineering Study, prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012, for the duration of project construction. 2. The applicant shall provide a Temporary Erosion and Sedimentation Plan designed pursuant to the Department of Ecology's Erosion and Sediment Control Requirements outlined in Volume 11 of the 2005 Stormwater Management Manual and provide staff with a Construction Mitigation Plan prior to issuance of construction permits. This mitigation measure shall be subject to review and approval of the Development Services Division. 3. The applicant shall provide weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the Project Engineer of record to the Public Works inspector. 4. Because of moisture -sensitive fine-grained soils mantling the site and the higher gradient areas within the site the geotechnical study recommends that grading and foundation construction be carried out and completed within the dryer period of the year from April 1 through October 31 unless otherwise approved by the Development Services Division. Therefore, the applicant shall adhere to a construction schedule involving grading and foundation work during the dryer period of the year. 5. The applicant shall pay a Parks Mitigation Fee based on $530.76 per each new single family lot prior to recording the final plat. 6. The applicant shall be required to pay a Traffic Mitigation Fee based on $75.00 per each new average daily vehicle trip associated with the proposed project prior to recording of the final plat. 7. The applicant shall be required to pay a Fire Mitigation Fee based on $488.00 per each new single family lot prior to recording the final plat. 4. Staff Review Comments Representatives from various City departments have reviewed the application materials to identify and address issues raised by the proposed development. These comments are contained in the official file, and the essence of the comments has been incorporated into the appropriate sections of this report and the Departmental Recommendation at the end of the report. City of Henron Cammunrr , and Economic D +menr Departmeru Report to the Henrrn er WILSON PARK 11 PLAT & PUD 1-bAl2-013. ECF. PP, PPUD PUBLIC 11F.ARIN'G DATE: June 12, 2012 Pulte 7 gf37 5. Consistency with the Planned Urban Development Regulations a) Compliance with the Underlying Zoning Designation (Code provisions restricted from modification through the PUD process): The subject site is designated R-1 and R-14 on the City of Renton Zoning Map (Exhibit 2). The proposed development would allow for a 10 -lot, 1 -tract subdivision of an 2.15 acre site (Exhibit 3)- i. Use: A planned urban development may not authorize uses that are inconsistent with those allowed by the underlying zone. The applicant is proposing the development of single family homes. Both the R-1 and R-14 Zones permit detached dwellings. ii. Density: The number of dwellings units shall not exceed the density allowances of the applicable base zone. The R-1 Zone allows a density of 1.0 dwelling units per gross acre. The R-14 Zone allows a maximum density of 14 dwelling units per net acre. According to the density worksheet (Exhibit 7) submitted with the application, the proposed project would have a net density of 6.4 dwelling units per net acre and, therefore, complies with the density requirement. Code Interpretation CI -30 (Exhibit 8) allows for properties with more than one zoning classification to be allowed to average residential density across the site provided this is accomplished through the Planned Urban Development process. This Code Interpretation has been posted on the City's webpage for a 14 -day comment period, and the appeal period for the interpretation ends at 5:00 pm on June 14, 2012. In order to ensure that only one dwelling unit is constructed on each lot within the R-14 Zone, staff recommends that the applicant be required to place a restrictive covenant on each of the lots indicating that only detached single family units could be constructed. h) Code Provisions That May Be Modified: In approving a Planned Urban Development, the City may modify any of the standards of chapters 4-2 Zoning Districts - Uses & Standards, 4-4 City -Wide Property Development Standards, and 4-7 Subdivision Regulations and RMC 4-6-060 Street Standards, except as listed above in subsection "a)". If all conditions of approval are complied with the proposed Wilson Park lI Plat complies with all the City of Renton's development regulations including; chapters 4-2 Zoning Districts - Uses & Standards, 4-4 City -Wide Property Development Standards, and RMC 4-6-060 Street Standards, with the exception of the requested modifications identified in Table A below. Table A REQUESTED MODIFICATIONS F90" ON MUNICIPAL CODE (RMI[? j RMC # Required per RMC Requested Modification RMC 4-2-11OA: Minimum Lot Size R-1: 1 Acre, Except 10,000 sq. ft. R-1: Lots 5,560 to 6,778 sq. ft. for cluster development. R-14: Plat would include lots R-14: No minimum lot size; from 5,560 sq. ft. to 5,909 sq. ft.; however developments over 9 all lots would be for detached lots shall incorporate a variety of single family homes. home sizes, lot sizes, and unit Cita of Renton Community and Economic D ?mens Department Report to the Hearing !:;rammer WILSON PARK 11 PLAT & PUD LUA12-013, Eff, PP. PPUD PUBLIC. HEARING DATE: June 12, 2012 Page 8 of 31 RMC 4-2-11OA: Minimum Lot Width RMC 4-2-11OA: Minimum Front Yard Setback clusters. R-1: 75 feet for interior lots; 85 feet for corner lots R-14: No minimum lot width Staff Comment: The applicant has not requested a modification from this standard. However, due to the small lot sizes requested above, staff believes a modification from this standard would be required to maintain a buildable lot. R-1: 30 feet R-14: Varies; however for lots with garage access from a street, require a minimum of 18 feet from the face of the garage to the back of the curb or sidewalk/path. RMC 4-2-11OA: Minimum Side Yard f R-1: 15 feet R-14: 4 feet for detached units Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone with regard to minimum tot width. R-1: Lots are proposed to be from 55 ft. to 66 ft. wide. R-14: Lots would be 55 ft. to 57 ft. wide. Staff Comment: Staff recommends requiring that the plat conform to the R-8 Development Regulations for minimum lot width. Minimum lot width would be 50 feet for interior lots and 60 feet for corner lots. Therefore, Lot 1, shown at 57.74 feet in width would need to be a minimum of 60 feet in width in order to conform to the R-8 standards for corner lots. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the minimum front yard standards of the R-8 Zone, which requires a 15 foot front yard setback. Staff further recommends that a minimum setback of 18 feet be required from the face of the garage to the back of the sidewalk to allow an aroorooriate area for oarkina. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone for minimum side Yard Setbacks, which is 5 feet. C'rt OfRenlozz C.ommunhy and Economic D Iment Department Reporl to the Hearing Examiner WILSON- PARK 11 PLAT & PUP LU.412-013. I:CF. PP. PPUD PUBLIC I1FARING DATE: lune 12. 2012 Page 9 of 31 RMC4-2-110: Minimum Side Yard R-1: 20 feet Along a Street R-14: n/a RMC 4-2-11OA: Minimum Rear YardI R-1: 25 feet setback R-14: 12 feet RMC 4-2-11OA: Maximum Building Coverage RMC4-2-110A: Maximum Impervious Coverage R-1: 20% R-14: n/a Staff Comment: The applicant has not requested a modification from this standard. However, due to the small lot size requested above, staff believes a modification from this standard would be required to maintain a buildable lot. R-1: 30% R-14: 85% Staff Comment: The applicant has not requested a modification from this standard. However, due to the small lot size requested above, staff believes a modification from this standard would be required to maintain a buildable lot. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone for Minimum Side Yard Setback along a street, which is 15 feet (Lot 1). Further, staff recommends that the appropriate setback from Tract A and the pedestrian path within an easement be 5 feet. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone for the Rear Yard Setback, which is 20 feet. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone for Maximum Building Coverage. For lots larger than 5,000 s.f. this is 35% or 2,500 s.f. whichever is greater. None Proposed. Staff Comment: Staff recommends that the applicant be subject to the standards of the R-8 Zone for Maximum Impervious Coverage, which is 75%. Cil}' of Renton Commumn and L'conomw 1) ,menu Department Repun to fhe Hearing—IIP7nE7 WILSOA' PARK 11 PLAT & PUD LU.912-013. ECF. PP. M.0 PUBLIC IIG 4Rf'G DA TL: June 12, 2012 Page 10 of 31 RMC 4-2-115F. 1. Site Design, Lot R-1: N/A Stoff Comment: Staff Configuration recommends approval of the R-14: Developments of more requested deviation and than nine (9) detached dwellings recommends that the shall incorporate a variety of requirements of the R-8 home sizes, lot sizes, and unit Residential and Open Space clusters. Standards be followed. This standard requires that: 1. Lot width variation of 10 feet minimum of one per 4 abutting street fronting lots, or 2. Minimum of 4 lots sizes minimum of 400 gross square feet size difference, or 3. A front yard setback variation of at least 5 feet minimum for at least every 4 abutting street fronting lots. RMC 4-2-115F.1. Site Design, R-1: N/A Staff Comment: Staff Garages recommends approval of the R-14: Recessed 8 feet from the requested deviation provided that front, or detached; garage similar the requirements of the R-8 to home; minimum 18 -foot Residential and Open Space driveway length from the face of Standards be followed. garage to the back of the sidewalk (unless accessed by This standard requires that the alley) garage be recessed at least 8 feet from the front of the house, or located so that the roof extends at least 5 feet; or located so that the entry does not face a public and/or private street or access easement, or sized so that it is no greater than 50% of the width of the front fogade at ground level, and that the portion wider than 26 feet wide is set back at least 2 feet. In addition; staff recommends 00i of tewori Commumiy and Economic D 3ment Department Report to the hearing Examiner WILSON PARK CI PLAT & PUD LU:912-013. ECF. PP, PPUD PUBLIC HF.,IRNCr DATE: June 12, 2012 Page 11 (?f31 RMC 4-2-115F.3. Residential Design, Scale, Bulk, and Character b) PUD Decision Criterion: R-1: N/A R-14: Primary building form shall be dominating; primary porch plate heights shall be one story; different colors shall be used to differentiate the same models and elevations; and no more than 2 of the same model and elevation shall be built on the same block frontage and shall not be abutting. . that there be a minimum of 18 feet of driveway length from the face of the garage to the back of the sidewalk. Staff Comment: Staff recommends approval of the requested deviation and recommends that the requirements of the R -S Scale, Bulk, and Character Standards be followed. This standard requires that: A variety of elevations and models that demonstrate a variety of floor plans, home sizes, and character shall be used. Additionally, both of the following are required: 1. A minimum of three (3) differing home models for each ten (10) contiguous abutting homes, and 2. Abutting houses must have differing architectural elevations. i. Demonstration of Compliance and Superiority: Applicants must demonstrate that a proposed development is in compliance with the purposes of the PUD regulations and with the Comprehensive Plan, that the proposed development shall be superior to that which would result without a planned urban development, and that the development will not be unduly detrimental to surrounding properties. Comment: If the conditions of approval are met, the applicant will have demonstrated compliance with the PUD regulations and the Comprehensive Plan. The applicant will have demonstrated that the development is superior to that which would result without a PUD and will not be detrimental to surrounding properties. The development of this site as a PUD results in a superior design than would result by the strict application of the Development Standards for many reasons. First, the proposed plat layout provides for a the protection of the steep slope area to the east. Second, the plat would provide for recreational amenities beyond code requirements. Third, the plat layout increases the quality of the internal circulation system throughout the development. Fourth, the 0h of Renton Community and Economic D >meni Deportment Reporl la the Hearing Examiner WILSON' PARK 11 PLAT & PUD I t-.412-013, f:'Ch. P . PPUD PUBLIC 11EARIR-G DATE: June 12, 2012 Page 12 of 31 proposed subdivision is a significant improvement over a design that would meet both the R-1 and R-14 standards. This proposed design can provide for the aforementioned amenities because of the modifications requested in Table A above. ii. Public Benefit: The applicants shall demonstrate that a proposed development will provide specifically identified benefits that clearly outweigh any adverse impacts or undesirable effects of the proposed planned urban development, particularly those adverse and undesirable impacts to surrounding properties, and that the proposed development will provide one or more of the following benefits than would result from the development of the subject site without the proposed planned urban development: Critical Areas: Protects critical areas that would not be protected otherwise to the same degree as without a planned urban development; or Natural Features: Preserves, enhances, or rehabilitates natural features of the subject property, such as significant woodlands, native vegetation, topography, or noncritical area wildlife habitats, not otherwise required by other City regulations; or Public Facilities: Provides public facilities that could not be required by the City for development of the subject property without a planned urban development, or Use of Sustainable Development Techniques: Design which results in a sustainable development; such as LEED certification, energy efficiency, use of alternative energy resources, low impact development techniques, etc.; or Overall Design: Provides a planned urban development design that is superior to the design that would result from development of the subject property without a planned urban development. A superior design may include the following: OOoen Space/Recreation: a) Provides increased open space or recreational facilities beyond standard code requirements and considered equivalent to features that would offset park mitigation fees in Resolution 3082; and b) Provides a quality environment through either passive or active recreation facilities and attractive common areas, including accessibility to buildings from parking areas and public walkways, or Circulation/Screening: Provides superior circulation patterns or location or screening of parking facilities, or Lands0gPingIScreening: Provides superior landscaping, buffering, or screening in or around the proposed planned urban development; or Site and Building Design: Provides superior architectural design, placement, relationship or orientation of structures, or use of solar energy; or Alleys: Provides alleys for proposed detached or attached units with individual, private ground related entries. City of Renton Conununity and F.conornic 1) WILSON PARK I1 PLAT & PUD Pb'B1JC Hk-ARINGDA TF: June 12. 7012 Table B Ment Deparfinew Report to the Nearing F.zammer Li.;,412-013, FCF, PP, PPCD Page 13 of 31 PUBLIC BENEFIT PROVIDED: CRITICAL AREAS, NATURAL FEATURES & OVERALL DESIGN CRITICAL AREAS: The site contains steep slopes greater than 40% which is termed to be a geotechnical hazard. The City critical areas regulations provide for protections to these features, however the proposed development increases these protections by protecting the steep slope within a tract that would also serve as the common open space and recreation area. A trail provided on the flat area of the tract would separate five of the new lots from the steep slope area. The open space tract would also connect to a comparable open space tract on Wilson Park I that was set aside to address requirements of the Urban Separator Overlay Regulations (RMC4-3-110E, 2.a.ii). Both the subject plat and Wilson Park I are required to set aside 50% of the area of the site located within the Talbot Urban Separator as a non -revocable open space tract. For Wilson Park II, the Urban Separator is assigned to 38,326 square feet. The project proposes to set aside 19,164 square feet, or 50% of this area. Staff recommends that the applicant record a Native Growth Protection Area Easement over the tract such that it is not disturbed. NATURAL FEATURES: The site is currently undeveloped. The site contains a total of 82 trees of 6 -inch caliper or larger, 21 are within the proposed public right-of-way, and 3 are located in critical areas and their buffers resulting in 58 protected trees on site (Exhibit 9, 10). Of these, 21 trees are within the R-1 zone, and 37 trees within the R-14 zoned portions of the property. The R-1 zone requires 30 percent tree retention of the protected trees on site, while the R-14 requires 10 percent tree retention. At a 30 percent retention rate in the R-1 zone, 6 trees would be required to be retained. At 10 percent retention rate in the R-14 zone, 4 trees would need to be retained. This is a total of 10 trees required to be retained. The applicant has identified 10 trees that would be retained thus meeting the requirement. In addition, the applicant proposes to plant 40 new trees on site, which includes street trees within the right-of-way and ornamental trees within Tract "A" the common open space and Native Growth Protection Area Easement. The applicant's provided conceptual landscape plan (Exhibit 11) indicates proposed ornamental trees, shrubs, and groundcover includes the proposed locations for the plantings. For the street trees, the applicant proposes Parrotia persica (Persian Ironwood trees), 1-1/2" caliper; with two planted for each of Lots 1 through 9. Cercis Canadensis (Forest Pansy Redbud trees), 1-1/2" caliper are proposed at the entrance to the plat along the south side of Lot 1 and within the right-of-way for Lot 10. Thuja plicata Western Red Cedar trees), 6 -foot high, are proposed along the south boundary of Tract A/Lot 10, along the proposed walking path. Tsuga heterophylla (Western hemlock), 6 -foot high, are proposed between the common boundary between Lots 6, 7, 8 and the common open space tract, where the walking path is provided. The proposed plant palette also contains Mahonia aquifolium (Tall Oregon Grape), Ribes sanguineum (Red Flowering Currant) as shrubs and Arcostaphylos uva-ursi (Kinnikinnick), Gaultheria shallon (Salal) and Polystichum munitum (Sword fern) as ground cover. The conceptual landscape plan is acceptable provided that additional trees are proposed on the south side of Lot 1 within the right-of-way, and within the right-of-way for the street improvements along South 55th Street. As such, staff recommends as a condition of approval that the applicant provide a City of Renton Communew and Economic D ament Deportment Report to the hearing Examiner WILSON PARK 11 PLAT & PUD LU.912-013, ECF PP. PPUD PUBLIC IILARING DATE: .lune 12. 2012 Page 14 of 3l detailed final landscape pian that shall be submitted and approved by the Current Planning Project Manaizer prior to final PUD approval. OVERALL DESIGN: 1. Open Space/Recreation: In addition to private open space provided on each proposed lot, the applicant has proposed to provide a passive recreation area primarily located on the eastern portion of the site, and wrapping around the north part of Lot 6 and the south boundary of Lot 10. This 19,154 square foot (0.44 acre) open space would include a pergola structure, landscaping and two picnic tables, a soft surface looped trail system through the development, and would also comprise the steep slope area beyond to the north and east. RMC 4-9-150E requires that PUD's provide large concentrated areas of open space, equivalent to 10% of the site's gross area. The site is 93,801 sq. ft. and the provided open space tract is 19,154 sq. ft, comprising approximately 20% of the site, and exceeding the open space standards by 9,784 square feet. The overall passive and active recreation opportunities proposed for the subject development are beyond the standard code requirements. The proposed open space and recreation on the site provide the opportunity for passive recreation. The looped trail system is approximately 510 lineal feet long, offering the opportunity for walking. However, it should be noted that the split -rail fence or pergola/gazebo designs are not reflected on the Landscape Plan or the Plat Plan, as such staff recommends a condition of approval that the applicant provide a detail of the proposed pergola/gazebo and fence design and location as a part of the final detailed landscape plan. These details shall be submitted and approved by the Current Planning Project Manager prior to final PUD approval. 2. Circulation: The proposed preliminary plat provides for an appropriate pedestrian circulation system. In addition to the proposed soft surface pedestrian path, discussed above, the applicants have proposed sidewalks along Road A consistent with the residential character of the development. Comments received from surrounding property owners concern the ability of school buses to safely serve the Wilson Park Il plat. The applicant has observed that presently school buses travel east on 55th Avenue South in the morning, stopping in 55th Avenue South to pick-up students. The buses then travel west in the afternoon, stopping in 55th Avenue South to drop-off students. However, upon inquiry with the Renton School District, it was determined that these are actually Kent School District (KSD) buses that serve students attending schools in the Kent School District, for properties on the south side of South 55th Street. The subject site is actually within the Renton School District (RSD). RSD busses do not travel on South 55th Street, and the closest school bus stop is located at the intersection of South 55th Street and Talbot Road South, approximately 700 feet to the west. Staff recommends that the project provide for an asphalt walking path from the entrance of the development (on the north side of South 55th Street) to the intersection of Talbot/S. 551h, in order to facilitate walking to and from the bus stop. In addition to sidewalks and the proposed pedestrian path, the proposed preliminary plat also provides for appropriate vehicle circulation system. The road system connects with the Wilson Park Plat located immediately to the north. The road was originally approved as part of Wilson Park and has'not yet been constructed. Wilson Park I is dependent upon the construction of this road, as is Wilson Park 11. Staff recommends that if Wilson Park II moves forward prior to Wilson Park I, that the public street be constructed with an approved emergency turnaround. Cih, o f Renton Community and Economic L anent Department Reporl to the hearing Examiner fVILSON PARK 11 PLAT & PUD LUA12-013. ECF, PP. PPCI) PUBLIC HEARING DATE: June 12. 2012 Page l5 of 31 I Landscaping/Screening: The proposed landscape plan for the entire site, and in particular the open space tract is superior to what would be required by Renton's Municipal Code, as discussed above under "Natural Features". 4. Site and Building Design: The qualities of the proposed site design has been addressed above under, "Critical Areas", "Natural Features", and the subsections of "Overall Design". The above comments address such things as road design and pedestrian circulation, critical areas protection and enhancement, as well as increased landscaping and recreational opportunities. All these amenities contribute to the overall superior site design. The 10 proposed lots are accessed off a public street, and would be representative of a typical plat for detached single family homes. Homes would be subject to the Residential Design Standards, and as such no building design is required at this time. The proposal would protect the environmentally critical areas, and passive recreational opportunities are proposed. 5. The orientation of the lots allows for access to solar energy, as all of the lots are east/west. All homes will be subject to the residential design standards. Since the plat is most representative of plats designed to meet R-8 zone, staff recommends that the homes within the plat meet the R-8 residential design standards with minor modifications. For example, staff suggests that garages be setback a minimum of 18 feet from the back of the sidewalk to allow appropriate area for apron parking. Compliance with these standards will be reviewed at the time of building permit application. Due to the level of detail needed to identify compliance with the residential design standards this review is best left for building permit stage. b. Alleys: The proposal is for a single two single tiers of lots front on an existing road easement approved as part of the Wilson Park I Plat. An alley configuration is not possible given the existing road location. iii. Building and Site Design: Perimeter: Size, scale, mass, character and architectural design along the planned urban development perimeter provide a suitable transition to adjacent or abutting lower density/intensity zones. Materials shall reduce the potential for light and glare. Comment: Proposed landscaping on the south boundary of Lot 10 would provide some screening of when viewed from South 55th Street. Proposed plantings of the southeast corner of Lot 1 would provide some incremental screening for Lot 1 when viewed from 55th Avenue South. Additional planting within the right-of-way should be provided along 55th Avenue South. This would require dedication of additional right-of-way along the south boundary of the plat, between the new Road A west to the southwest corner of the site. The scale, mass, character and architectural design would be of a detached single family residential development. Due to the existing split zoning of the parcel (both R-1 and R- 14 Zone) staff recommends as a condition of approval that the project not conform to either the R-1 or the R-14 Residential Design standards; rather that the project be required to comply with the Residential Design Standards applied to the R-8 Zone resulting in a compatible size, scale, mass, character and architectural design for the ON of Rentan Communifi and Economic D invent Deparlment _ Report to the HeurrnK L•xuvniner 4WILSON PARK If PLAT & PUD LUA12-013. ECF: PP.PPUD PUBLIC HEARIAG DATE: June 12. 2012 Page 16 Qf 31 overall development. The proposed lot sizes are comparable with the R-8 Zone, and the development would be most like R-8 development. Interior Design: Promotes a coordinated site and building design. Buildings in groups should be related by coordinated materials and roof styles, but contrast should be provided throughout a site by the use of varied materials, architectural detailing, building orientation or housing type. Comment: As mentioned above in Table B, the interior site design promotes quality pedestrian and vehicular circulation, increased critical area protection, promotes safety and by buffering the steep slopes area. All homes would be required to comply with the R-8 development design standards which would result in coordinated, yet varied roof styles and materials, architectural detailing, and a variety of home styles throughout the development. iv. Circulation: Provides sufficient streets and pedestrian facilities: The planned urban development shall have sufficient pedestrian and vehicle access commensurate with the location, size and density of the proposed development. All public and private streets shall accommodate emergency vehicle access and the traffic demand created by the development as documented in a traffic and circulation report approved by the City. Vehicle access shall not be unduly detrimental to adjacent areas. Comment: The subdivision would gain access from 55th Avenue South. A new street constructed for Wilson Park I bisects the two single tiers of lots and connects to the Wilson Park I site immediately abutting and north of Wilson Park H. All of the proposed lots and the open space tract would have access to the public street. Proposed pavement width is 25 feet, which allows parking on one side of the street. Staff recommends that the parking be allowed on the east side of the street in order to address concerns expressed during SEPA review regarding the direction that vehicles would be parked based on travel patterns. Five-foot wide sidewalks and 8 -foot wide landscape strips are proposed on both sides of the street. In addition, a 3 -foot wide walking path is proposed across the north, east and south portions of the eastern tier of lots. Most of this path is within Tract A, with the exception of a section along the south boundary of Lot 10. The walking path would be concrete near the proposed gazebo on the north portion of the site and soft surface for the remainder of the pathway within the open space tract. Staff recommends that the section on the south side of Lot 10 be revised to meander within the landscaped area in the side yard of Lot 10. The PUD would have sufficient pedestrian and vehicle access based on the location, size and density of the development, if all conditions of approval are met. See Table B, Public Benefit, subsection: Overall Design 2. Circulation above for additional discussion on pedestrian and vehicle circulation. Frontage improvements are required along South 55th Street. The property has frontage in two locations, where the proposed street intersects South 55th Street, and where a portion of Tract A fronts on South 55th Street. In both cases, the applicant is required to construct curb, gutter, 5 -foot wide sidewalks, and an 8 -foot wide planting strip. The City of Rennin Communay and Economic D me nt Deparimeni Report to the Hearing F,xmnrner WILSOON PARK If PIAT & PUD Lf"412-013. ECF, PP. MID PUBLIC HEARING DATE - June 12. 2012 Page 17 of 3l applicant's proposal indicates a 5 -foot wide sidewalk along South 55th Street on the south side of Lot 1. No planting strip is proposed within the South 55th Street right-of- way. No street improvements are proposed within the right-of-way for South 55th Street for the portion where Tract A fronts on the street (Exhibit 2, 11). Staff recommends that the applicant be required to provide the required street improvements and landscaping, and that these be shown on the construction engineering plans, and final detailed landscape plan, during the Final PUD and Final Plat process. The internal street is designed to accommodate emergency vehicle access and the traffic generated by the project, provided that the street connects through Wilson Park I. In the event that Wilson Park I is not constructed concurrent or prior to Wilson Park II, then the applicant should be required to provide an emergency turnaround within the plat. Promotes safety: Promotes safety through sufficient sight distance, separation of vehicles from pedestrians, limited driveways on busy streets, avoidance of difficult turning patterns, and minimization of steep gradients. Comment: The applicant submitted a Traffic Impact Analysis Report (Exhibit 12) prepared by TraffEx (Northwest Traffic Experts, dated June 23, 2009 and supplemented January 25, 2012). The report indicates that the proposal would utilize the same access to South 55th Street s the approved Wilson Park I Plat. The site access street intersects South 55th Street on the outside of a horizontal curve on South 55th Street to optimize sight distance in both the east and west direction for vehicles entering and exiting the site. The report also indicates that the horizon year for the study is considered to be 2014, as that is the year construction of both plats is anticipated. The study indicated the increase in traffic with the proposal and determined that the traffic would operate at acceptable levels at the intersection of South 55th Street and the new street within the plat. The Level -of -Service (LOS) with the project was determined to be LOS B for future 2014 conditions. Previously, the site distance on South 55th Street was evaluated as part of Wilson Park I. It was determined then that the City of Renton intersection and stopping sight distance requirements in both the east and west directions would be met. Comments received from surrounding property owners concern the ability of school buses to safely serve the plat (Exhibit 14). The applicant has observed that presently school buses travel east on South 55th Street in the morning, stopping in South 55th Street to pick-up students. The buses then travel west in the afternoon, stopping in South 55th to drop-off students. While it was originally anticipated that this practice would continue with the project, and that children would wait together for pick-up, an inquiry to the Renton School District (RSD) revealed that these are actually Kent School District buses, which do not serve the subject plat. RSD does not operate on South 55th Street, and would require that students walk approximately 700 feet to the west to be picked up at the corner of South 55th Street and Talbot Road South. In order to provide an appropriate safe route to schools, staff recommends that the applicant be required to provide a walking path within the improved right-of-way, with a minimum 5 -foot asphalt path, on the north side of South 55th Street, from the entrance to the plat to the intersection of South 55th Street and Talbot Road South separated from the traffic lane City of Renton Comrnunaty and Economic D Ment Department Report to the Hearing Examiner WILSON PARK 11 PLAT & PbD UJA12-013, ECF, PP. PPUD PUBLIC HEARING DA 11i. June 1 Z. 2012 Page 18 of 31 by C -curb. This should be installed at the time that street and utility improvements are being installed. A lighting plan was not included in the applicant's submittal packet; therefore, it is not clear how the proposed pedestrian pathways would be illuminated at night. Although, staff recommends that the area near the concrete path and pergola be illuminated at night, staff further recommends that the soft surface trail be unlit or minimally lit at night. Staff recommends, as a condition of approval, that the applicant submit a lighting plan for review and approval by the Current Planning Project Manager prior to utility construction. The lighting plan shall contain pedestrian lighting in addition to building and landscaping lighting if proposed. The proposed development would result in one driveway for each new lot. In addition, one access point is proposed from South 55th Street to the development, Road A. An additional emergency access is provided within Wilson Park I to South 55th Street. Based on the road width, parking would be permitted on one side of the new street. Staff recommends that parking be allowed on the east side, in order to acknowledge customary use and anticipated circulation. These design considerations/requirements would result in a circulation system that would avoid difficult turning patterns, minimizes steep gradients and minimize driveways on busy streets. Once the applicant has fulfilled the conditions of approval (noted above); the promotion of safety could be accomplished. Provision of a system of walkways: Walkways that tie residential areas to recreational areas, transit, public walkways, schools, and commercial activities. Comment: See Table B "Public Benefit, Subsection: Overall Design 1 and 2" above. The site is somewhat isolated and is constrained by topography. Street frontage improvements along 55th Avenue South would not tie into other existing sidewalk or walkway systems. The internal pathway would provide internal circulation and would connect to the sidewalks within the plat. There is no school bus stop for the Renton School District in close proximity. According to the Renton School District, the closest bus stop is located at the corner of Talbot Road and 55th Ave South, approximately 700 feet to the west of the entrance road. The site is constrained by natural topographical features and connections to surrounding areas are difficult due to the topography and the 55th Ave South. The subject site is located on periphery of the City boundary, and is relatively isolated from commercial zoned property. There is no existing access to commercial development in or near the subject site and no new access proposed for pedestrians. Provides safe efficient access for emergency vehicles: Comment: If the roadways are designed per recommended standards (Exhibit 2), the development would provide safe, efficient access for emergency vehicles. However, if the subject plat is constructed without Wilson Park I or prior to Wilson Park I, there would not be a sufficient turning radius for emergency vehicles and a temporary emergency vehicle turnaround would need to be provided on site. Therefore, staff recommends as a condition of approval that in the event that Wilson Park I is not constructed and recorded first or at all, Wilson Park 11 shall be required to provide City of Renton Communi1y and Econumic LX Ment 1)eparhnent Report to the Hearing Examiner 47LSONPARi: 11 MAY'& N!1) LU,412-OJ3. ECF, PP, PPUD PUBLIC HEARING DA 7E: Aw 12, 2012 Page 19 of 31 appropriate emergency access, per the review and approval of the Development Service Project Manager and the Fire Marshal. This shall be accomplished by providing an acceptable emergency vehicle turnaround, prior to the recording of the plat. V. infrastructure and Services: Provides utility services, emergency services, and other improvements, existing and proposed, which are sufficient to serve the development. Comment: Water service for the development would be provided by the Soos Creek Water and Sewer District. Water availability certificates will be required from the Soos Creek Water & Sewer District prior to Construction Permit. Based on the provided Conceptual Utilities Plan (Exhibit 13), there is an existing sewer main located in 55th Avenue South. The applicant has proposed to connect to this existing main and extend an 8 -inch sanitary sewer line to provide sewer to the development. This plan sheet also identifies an 8 -inch water line extension from 55th Avenue South through the subject plat and to the Wilson Park I plat located to the north. With receipt of the water availability certificate, the development could provide sufficient service to the lots. Fire protection would be provided by the City of Renton Fire Department. New impervious surfaces would result in surface water runoff increases. A Technical Information Report (dated May 5, 2009) was prepared by Baima and Holmberg Inc, for the previous Wilson Park I Plat. An addendum to this report was prepared by Offe Engineers, PLLC on February 28, 2012 to consider the current proposal. The May 2009 report includes an analysis of upstream tributary drainage which states that the parcel to the east drains onto the site, with no problems related to runoff. The Level 1 Downstream Drainage Analysis in the report states that runoff from the site flows west into lots in the adjacent Geneva Court development. The majority of the existing runoff from Wilson Park It collects along the west property line via sheet flow and continues downstream over the vacant property to the west. This flow collects in a stormwater pond/bioswale facility located at the intersection of Talbot Road South and South 53rd Place approximately 750 feet downstream from the site. This facility outfalls through an 18 -inch pipe to the west side of Talbot Road South into a poorly defined channel flowing into the woods. The flows then pass through a 12 -inch culvert under a walking path and continue to flow west to a wooded wetland area more than a quarter mile downstream from the site. Flows into the ditch along South 55th Street continue west in a rock lined channel along the north side of the street to the intersection of Talbot Road South and South 55th Street. The channel is eroded and shows signs of flowing into the street. Flows from the ditch along Talbot Road South collect in the storm system about 850 feet downstream from the site eventually flowing into Springbrook Creek at about 1,800 feet downstream from the site. The Creek continues flowing west to about one-half mile downstream of the site where it enters a box culvert crossing SR 157. The Technical Information Report indicates that there are no apparent drainage problems. The amended February 28, 2012 report evaluates the addition of the subject 10 -lot plat. The original stormwater system for Wilson Park I and located within the street that would serve both Wilson Park I and II was sized to accommodate Wilson Park I lots and the new streets including the access street located within Wilson Park II. The addendum provides calculations intended to evaluate the sizing of the storm treatment facility for the two projects. The report notes that City of Renton's 2009 Drainage Manual requires City of Renlon Commune)- and Economic T 7menl Department Report to the ,hearing Examiner WILSON PARK 11 PLAT & PLI) LLA12-013, F_CF, PP, PPUD PUBLICHEARING DATE. June 12. 2012 Page 20 of 31 Best Management Practices (BMP's) for new developments. One BMP's is to restrict impervious areas on future lots to help reduce runoff, mitigate for development, and minimize the treatment system needed for the project. This is known as a "Restrictive Covenant" provision and was utilized as part of a preliminary sizing of the future system for both Wilson Park 1 and II. The applicant intends to utilize the Restrictive Covenant provision and limit impervious surface on each of the new lots in both Wilson Park I and II to 3,300 square feet per lot. By limiting the impervious area for homes, patios, driveways and walkways, the proposed stormwater vault will be of an appropriate size to accommodate both developments. The applicant has also intended to develop both plats at the same time. Comments received from surrounding property owners (Exhibit 14) expressed concern as to whether the vault was sized appropriately to accommodate both projects. The applicant has stated that the vault is sized to the 2009 drainage manual and will provide the necessary volume and capacity for both projects. vi. Clusters or Building Groups and Open Space: An appearance of openness created by clustering, separation of building groups, and through the use of well-designed open space and landscaping, or a reduction in amount of impervious surfaces not otherwise required. Comment: The uniqueness of the zoning of the site, in addition to the area affected by steep slopes, results in a necessity to cluster development. The slope results in the preservation of open space in the form of a Native Growth Protection Area Easement as well as recreation space. The requested lot size and setback modification allow for a clustered R-8 development that provides increased protection of critical areas creating an appearance of openness. This also allows for a more cohesive design rather than attempting to design for two different residential density designations on one site. (See additional discussion above in Table B "Public Benefit, Subsections: Critical Areas and Natural Features".) As noted in the previous sections, the proposed development would have usable passive recreation, including open space and landscaping. In order to maintain sufficient separation between buildings, staff recommends that the applicant be required to meet the R-8 side yard setbacks, as such all structures will maintain a minimum of 10 feet of separation. This spacing allows for emergency access and sufficient fire separation. vii. Privacy and Building Separation: Provides internal privacy between dwelling units, and external privacy for adjacent dwelling units. Each residential or mixed use development shall provide visual and acoustical privacy for dwelling units and surrounding properties. Fences, insulation, walks, barriers, and landscaping are used, as appropriate, for the protection and aesthetic enhancement of the property, the privacy of site occupants and surrounding properties, and for screening of storage, mechanical or other appropriate areas, and for the reduction of noise. Windows are placed at such a height or location or screened to provide sufficient privacy. Sufficient light and air are provided to each dwelling unit. Comment: The context of the subdivision, it's location in relation to existing development, and the topography of the site provide for privacy. Within the subdivision, unit to unit privacy would be provided by the side yard setback requirement. Exhibit XX shows that applicant has indicated that a split -rail fence would be used to define the area Cal- of Renton Communew and Economic I iment Department Report to the Hearen,K Examiner 3"".SON PARK H PLAT d, Pt,'D LUAJ2-OI3. ECF . PP, PPUD PUBLIC HE4RING DATE; June I2. 1012 Pane 21 of 3I between the back and side yard area of the lots and the soft surface pathway within Tract A. No specific fence detail has been provided, and there could be a tendency for future residents to construct privacy fences abutting the split -rail fence. Therefore staff recommends that the applicant provide a fence detail with the final landscape plan that is subject to the review and approval of the Current Planning Project Manager. Street trees are required either within the required landscape strip or in the front yard of the lot. As discussed above under Table B "Public Benefit, Subsections: Critical Areas and Natural Features'; the proposed walkways and landscaping are appropriate for the protection and aesthetic enhancement of the property. All homes would be required to be designed to meet the residential design standards for the R-8 zone. These standards would require windows on the front of the home, increasing access to light and air for each dwelling unit. Furthermore, each lot would have private front, side and rear yards, enhancing each lot with landscaping and access to light and air. viii. Building Orientation: Provides buildings oriented to enhance views from within the site by taking advantage of topography, building location and style. Comment: The lots are arranged in into two tiers of single lots. The ten lots would be oriented east/west. The site topography slopes down from east to west, resulting in a terraced effect after site grading. The proposed layout maximizes the use of topography is appropriate. Views would be territorial and to lower elevations to the west. ix. Parking Area Design: Design: Provides parking areas that are complemented by landscaping and not designed in long rows. The size of parking areas is minimized in comparison to typical designs, and each area related to the group of buildings served. The design provides for efficient use of parking, and shored parking facilities where appropriate. Comment: Required parking would be provided within garages attached to each home. Additional guest parking would be provided on the driveway aprons for each lot. Staff has previously recommended that the applicant provide minimum 18 -foot garage aprons from the face of the garage to the back of the sidewalk to provide for parking that does not result in vehicles overhanging the sidewalk. On -street parking would be provided along the new internal road on one side. Staff further recommends that this parking be allowed on the east side of Road A. The proposed parking is designed to provide efficient use of the site and would be appropriately screen by the provided garages. Adequacy: Provides sufficient on-site vehicular parking areas consistent with the parking demand created by the development as documented in a parking analysis approved by the City. Comment: Parking regulations require a minimum of two off-street parking spaces for detached dwellings. As proposed each lot would have adequate area to provide two off- street parking spaces. Additional parking would be available on the internal road or in the driveways of each lot. Sufficient on-site vehicular parking would be provided consistent with the demand created by the development provided that conditions of approval are complied with. City° of Renton Community and Economic D rment Department Report to the hearing F.xarrrinrr WILSON PARK II PLAT & PUD LUA12-0I3. ECT PP. PPUD PUBLIC HEARIA"G DATE: June 12. 2012 Page 22 of 31 X. Phasing: Each phase of the proposed development contains the required parking spaces, open space, recreation spaces, landscaping and utilities necessary for creating and sustaining a desirable and stable environment, so that each phase, together with previous phases, can stand alone. Comment: The applicant has not proposed to phase the subject development. As such, this criteria does not apply. xi. Development Standards Common O apen_S-Pace Standard: open space shall be concentrated in large usable areas and may be designed to provide either active or passive recreation. Requirements for residential developments are described below. Residential: For residential developments open space must equal at least ten percent 10%) of the development site's gross land area. L Open space may include, but is not limited to, the following: a) A trail that allows opportunity for passive recreation within a critical area buffer (only the square footage of the trail shall be included in the open space area calculation), or b) A sidewalk and its associated landscape strip, when abutting the edge of a critical area buffer and when a part of a new public or private road, or c) A similar proposal as approved by the reviewing official. ii. Additionally, a minimum area equal to fifty (50) square feet per unit of common space or recreation area shall be provided in a concentrated space. Comment: The proposed development is located on an 2.15 acre site, of which a portion on the east is located in a critical area. The applicant has dedicated an Open Space Tract A which totals 19,164 square feet within which is a soft surface trail that equals approximately 1,530 square feet. The proposed development would have 10 lots; 50 square feet of common space or recreation areas is required per unit, resulting in a requirement of an additional 500 square feet. To partially fulfill the common space requirement the applicant has proposed to provide an approximate 350 square foot common park that includes a concrete path, pergola/gazebo and landscaping. Staff recommends that the applicant enlarge this area to be at least 500 square feet in order to meet the minimum requirement. Suggestions for added recreation opportunities may include a community garden or fire circle or barbeque area. The park is located north of proposed Lot 6 and connects to the walking path through the remainder of Tract A. The overall location and design of the park, open space and trail are located as to create a quality open space/recreation area for the development, specifically if all conditions of approval are met. Private Open Space: Each residential unit in a planned urban development shall have usable private open space (in addition to parking, storage space, lobbies, and corridors) for the exclusive use of the occupants of that unit. Each ground floor unit, whether attached or detached, shall have private open space which is contiguous to the unit. The private open space shall be well demarcated and at least fifteen feet (15') in every City ofkenton Community and Economic D nnent Department Report to the Hearing Fxammer WILSOA PARK H PLAT & PUD L tT.Q 12-013, FCF, PP, PPUD 11L'81JC HE,4RM,G DATE.: June 12, 2012 Page 23 of 31 dimension (decks on upper floors can substitute for the required private open space). For dwelling units which are exclusively upper story units, there shall be deck areas totaling at least sixty (60) square feet in size with no dimension less than five feet (5'). Comment: Each lot would have a private yard in both the front and the rear of the lot. The recommended setbacks would provide for a minimum 15 -foot front yard and a 20 - foot rear yard, which could result in a private open space yard meeting or exceeding the 15 foot in every dimension. Compliance with this standard shall be reviewed at building permit stage. Installation_ and Maintenance of Common Open Space: All common area and open space shall be landscaped in accordance with the landscaping plan submitted by the applicant and approved by the City. Comment: Prior to the recording of the plat, common landscaped areas and the open space landscaping, and street trees must be installed. The applicant would need to provide for the maintenance of the common areas through the establishment of a HomeOwner's Association. Installation and Maintenance of Common Facilities: All common facilities not dedicated to the City shall be permanently maintained by the planned urban development owner by the property owners' association or the agents) thereof. Comment: Staff recommends, as condition of approval, the applicant be required to establish a home owners' association for the development, which would be responsible for any common improvements, including but not limited to the soft surface trail, landscaping, and park within the PUD prior to Final PUD approval. All common facilities, not dedicated to the City, shall be permanently maintained by the PUD home owners' association. 6. Consistengy with Preliminary Plat Criteria Approval of a plat is based upon several factors. The following preliminary plat criteria have been established to assist decision -makers in the review of the plat: a) Compliance with the Comprehensive Designation The site is designated Residential Single Family (RSF) and Residential Low Density (RLD) on the Comprehensive Plan Land Use Map. Land designated Residential Single Family is intended to be used for quality detached residential development organized into neighborhoods at urban densities. it is intended that larger subdivisions, infill development, and rehabilitation of existing housing be carefully designed to enhance and improve the quality of single-family living. Land designated Residential Low Density is intended for a range of low intensity residential and employment where land is either constrained by sensitive areas or where the City has the opportunity to add larger -lot housing stock at urban densities of 4-du/net acre, to its inventory: Cite of Renton Commmily and Economic D meet Deparunet Report to the Hc, rE Examiner WILSON PARK 11 PIAT R PUD LUA12-013. E(:F. PP, PPUD PUBLIC HEARIA'G DATE: June 12, 2012 Page 24 of 31 RSF Policy LU -158. Net development densities should fall within a range of 4.0 to 8.0 dwelling units per acre in Residential Single Family Neighborhoods. Policy Objective Met Not Met Policy LU -159. Maximum height of structures should not exceed two (2) stories in single- family residential neighborhoods. Policy Objective Met Not Met Policy EN -19. Allow land alteration only for approved development proposal or approved mitigation efforts that will not create unnecessary erosion, undermine the support of nearby land, or unnecessarily scar the landscape I areas subject to geologic hazards. Policy Objective Met Not Met Policy EN -28. Require trees and other vegetation along newly constructed or reconstructed streets to reduce impacts from development. Policy Objective Met [] Not Met Policy EN -36. Where appropriate combine environmentally sensitive areas with to provide public access and educational opportunities. Policy Objective Met Not Met Policy CD -1. Integrate development into natural areas by clustering development and/or adjusting site plans to preserve wetlands, steep slopes, and notable stands of trees or other vegetation. Natural features should function as site amenities. Use incentives such as flexible lot size and configuration to encourage preservation and add amenity value. Policy Objective Met Not Met b) Compliance with the Underlying Zoning Designation See Consistency with the Planned Urban Development Regulations and Table A. The proposed development would allow for the future construction of 10 new single-family dwelling units. Density: The site is zoned both R-1 and R-14, and the zone line See Consistency with the Planned Urban Development Regulations, subsection a). Lot Dimensions: See Consistency with the Planned Urban Development Regulations, Table A for requested modifications. As demonstrated in Table C below, all lots except Lot 1, meet the requirements for the requested minimum lot size, depth, and width as requested through the PUD. Lot 1 is a corner lot and would require that its minimum width be increased to 60 feet for meet the standard. There is sufficient room on the site to achieve this and keep the proposed lot count. City o/'Renlun Communih, and Economic D mment Deparanem WII SON PARK If PLAT rY PUD PUBLIC HFARIA(; DATE: June 12, 2012 Table C Report to the hearing F,xavnmer LUA12-013. ECF. PP. PPUD Page 25 of 31 As Proposed Lot Size Width Depth Lot 1 5,775 SF 57.74 feet 102.51 feet Lot 2 5,905 SF 57.60 feet 102.51 feet Lot 3 5,905 SF 57.60 feet 102.51 feet Lot 4 5,905 5F 57.60 feet 102.51 feet Lot 5 5,587 SF 57.47 feet 102.51 feet Lot 6 5,587 SF 55 feet 101 feet Lot 7 5,560 SF 55 feet 101 feet Lot 8 5,560 SF 55 feet 101 feet Lot 9 5,559 SF 55 feet 101 feet Lot 10 6,775 SF 66.41 feet 101feet In addition to the 10 proposed developable lots, the applicant has proposed 1 tract for, critical areas, recreation/open space, and access. For maintenance of the open space Tract A staff recommends as a condition of approval that all critical areas and their buffers be placed in a Native Growth Protection Easement (NGPE). However, such easement shall be written to provide access for the trail users. Furthermore, these areas shall be fenced with split rail fencing to separate the trail from the steep slope and to provide designated access points along the trail. Also, as a condition of approval staff recommends that a covenant shall be placed on all tracts restricting their separate sale and giving each lot owner within the plat an undivided interest in the tracts. This covenant should be recorded on the face of the plat, and/or concurrent with the plat recording, noting the recording number on the plat. Setbacks: See Consistency with the Planned Urban Development Regulations, Table A for requested modifications. Building Standards: See Consistency with the Planned Urban Development Regulations, Table A for requested modifications. ON of Renton Community and Economic 1) i'ILSDN PARK H PLAT & PUD PUBLIC HARING DATF' June 12, 2012 c) Community Assets ment Department Report to the Ifeartng F.xamrner LU.Q12-013, i(F, PP, PP11D Page 26 of 3I The site is sloped from the east to west and vegetated primarily with cottonwood, alder, maple, and fir trees. See Table B Public Benefit, subsection Natural Features and for discussion of tree retention, landscaping and plantings. The conceptual landscape plan submitted with the application includes the installation of street trees along the street frontage within the plat; however it does not show landscaping or street improvements for the street frontage on South 55th Street, as required by code. As such, staff recommends as a condition of approval that the street trees are shown on the final detailed landscape plan in compliance with the street tree standards. If the conditions of approval are complied with the development would demonstrate compliance with the landscaping regulations of the code. The applicant is required to submit and have approved a detailed landscape plan prior to final PUD and Final Plat recording. d) Compliance with Subdivision Regulations Streets: See Consistency with the Planned Urban Development Regulations, Table A for requested modifications and staff's recommendation for street development. In addition to the comments in the above Table A, street lighting meeting pedestrian lighting levels, in conformance with the residential street lighting interpretation, will be required for both the internal street sections. As such, staff recommends as a condition of approval, that a lighting plan be submitted with the construction permit application for review and approval by the Department of Community & Economic Development, Development Services project manager prior to building permit approval. All wire utilities shall be installed underground per the City of Renton UnderGrounding Ordinance. If three or more poles are required to be moved by the development design, all existing overhead utilities shall be placed underground. Construction of these franchise utilities must be inspected and approved by a City of Renton public works inspector prior to recording of the plat. Blocks: No new blocks will be created as part of the proposed plat. Lots: The shape, orientation, and arrangement of the proposed lots comply with the requirements of the Subdivision Regulations for the R-8 zone, subject to the requested modifications found in Table A above. In addition the proposal allows for reasonable redevelopment of land. All 10 lots are rectangular in shape and would provide sufficient building area. e) Reasonableness of Proposed Boundaries Access: The subdivision would gain access from South 551h Street at one access point, identified as "Road A". Road A would also provide access to Wilson Park I to the north. All of the proposed lots would be directly accessed off of Road A. Topography: The site is bounded by steep slopes east. The site contains areas of protected slopes (greater than 40%) in the northeastern portion of the property. This area City of Renton Community and Economic D )menf Department Report to the llearing Examiner WILSON PARI: II PLAT & PL -D LU412-013, ECF, PP, PPUD PUBLIC HEARING DATE: June 12. 2012 Page 27 of 31 of protected slopes would be contained within Tract A. There is also a cut slope on the west portion of the property that slopes up to about 6 to 12 feet. This slope likely resulted from the original land grading. Both geotechnical reports submitted conclude that the subject site is stable and can support the development provided the recommendations of the November 22, 2004 report are fully implemented and observed during construction. Relationship to Existing Uses: See PUD criterion iii Building and Site Design. f) Availability and Impact on Public Services (Timeliness) Police and Fire: Police and Fire Prevention staff indicates that sufficient resources exist to furnish services to the proposed development; subject to the condition that the applicant provides Code required improvements and potential impact fees, if applicable at the time of development/recording. Schools: According to the Draft Environmental Impact Statement for the City of Renton Land Use Element (January 16, 1992), the City of Renton has a student generation factor of 0.44 students per single-family residential dwelling. Based on the student generation factor, the proposed plat would result in 4 students (0.44 X 10 new lots = 4.4). It is anticipated that the Renton School District can accommodate the students generated by this proposal at the following schools: Benson Hill Elementary, Nelsen Middle School and Lindbergh High School. Renton Municipal Code provides for the collection of a school impact fee on behalf of the Renton School District, which is currently $6,392 per each new home, due at the time of building permit. Storm Water: New impervious surfaces would result in surface water runoff increases. A Technical Information Report (dated May 5, 2009) was prepared by Baima and Holmberg Inc, for the previous Wilson Park I Plat. An addendum to this report was prepared by Offe Engineers, PLLC on February 28, 2012 to consider the current proposal. The May 2009 report includes an analysis of upstream tributary drainage which states that the parcel to the east drains onto the site, with no problems related to runoff. The Level 1 Downstream Drainage Analysis in the report states that runoff from the site flows west into lots in the adjacent Geneva Court development. The majority of the existing runoff from Wilson Park 2 collects along the west property line via sheet flow and continues downstream over the vacant property to the west. This flow collects in a stormwater pond/bioswale facility located at the intersection of Talbot Road S and South 53rd Place approximately 750 -feet downstream from the site. This facility outfalls through an 18 -inch pipe to the west side of Talbot Road S into a poorly defined channel flowing into the woods. The flows then pass through a 12 -inch culvert under a walking path and continue to flow west to a wooded wetland area more than a quarter mile downstream from the site. Flows into the ditch along South 55th Street continue west in a rock lined channel along the north side of the street to the intersection of Talbot Road S and South 55th Street. The channel is eroded and shows signs of flowing into the street. Flows from the ditch along Talbot Road S collect in the storm system about 850 -feet downstream from the site eventually flowing into Springbrook Creek at about 1,800 -feet downstream from the site. The Creek continues flowing west to about one-half mile downstream of the site where it enters a box culvert Cas• ofRenlon Communify and Economic L rment Deparlment Report to 1he ffearing F_xanrmer WILSON PARK 11 PIAT & PUD LUM2-01.3. ECF, PP, PPUD PUBLIC IIEAPJ,,VG DATE: June Il, 1012 Page 28 of 31 r. crossing SR 167. The Technical Information Report indicates that there are no apparent drainage problems. The amended February 28, 2012 report evaluates the addition of the subject 10 -lot plat. The original stormwater system for Wilson Park I and located within the street that would serve both Wilson Park I and II was sized to accommodate Wilson Park I lots and the new streets including the access street located within Wilson Park II. The addendum provides calculations intended to evaluate the sizing of the storm treatment facility for the two projects. Water and Sanitary Sewer Utilities: See PUD criterion v. Infrastructure and Services. gj Compliance With Critical Area Regulations The project site includes areas with greater than 40% slope that are classified as critical areas. In addition, the site contains a small, isolated, unregulated wetland in the west portion of the site (Exhibit XX). The slopes are within the Talbot Urban Separator Overlay, and would be protected within Tract A, which would also include passive recreation in the form of a soft surface trail, pergola/gazebo, along with ornamental landscaping. In order to protect the critical area, the following conditions of approval are recommended by staff: 1. The common boundary between the native growth protection tract and the abutting land must be permanently identified. This identification shall include a permanent wood split rail fence and metal signs on treated or metal posts. The permanent wood split rail fence and signs shall be installed prior to Final Plat recording. 2. The following note shall appear on the face of the Final Plat and shall also be recorded as a covenant running with the land on the title of record for all affected lots on the title: "MAINTENANCE RESPONSIBILITY: All owners of lots created or benefitting from this City action abutting or including a native growth protection tract are responsible for maintenance and protection of the tract. Maintenance includes ensuring that no alterations occur within the tract and that all vegetation remains undisturbed unless the express written authorization of the City has been received." RECOMMENDATIONS: Staff recommends approval of the Wilson Park Preliminary Plat and Preliminary PUD, Project File No. LUA12-013, ECF, PP, PPUD subject to the following conditions: 1. The applicant shall comply with the 7 mitigation measures issued as part of the Determination of Non -Significance Mitigated, dated May 7, 2012. 2. The applicant shall record a restrictive covenant on each of the lots indicating that only detached single family units may be constructed, and any future accessory units allowed per the R-8 Development Regulations. This covenant shall be subject to the review and approval of the Current Planning Project Manager and City Attorney, and shall be recorded prior to the recording of the Final Plat. City of Renton Community and Economic D ment Department Report to the Hearing Examiner WILSON II PLAT & PUD LUA12-013, ECF. PP. PPUU PUBLIC HEARING DATE: June 12, 2012 Page 29 of 31 3. The project shall be subject to the Development Standards of the R-8 residential zone with respect to minimum lot size, minimum lot width, minimum side yard and side yard along a street setbacks, minimum rear yard setbacks, maximum building coverage, maximum impervious coverage. 4. The project shall be subject to the Development Standards of the R-8 zone with respect to the front yard setback, except that there shall be a minimum of 18 feet between the face of the garage and the back of the sidewalk. 5. The project shall be subject to the Residential and Open Space Standards of the R-8 Zone, provided that there shall be a minimum of 18 feet of driveway length from the face of the garage to the back of the sidewalk. 6. The applicant shall establish and record a permanent and irrevocable Native Growth Protection Area Easement (NGPE) on the property title for all critical areas and their buffers prior to Final Plat recording. The protective easement shall be held by current and future property owners; shall run with the land; and shall prohibit development, alteration, and disturbance within the easement except for the purposes of habitat enhancement as a part of an enhancement project, access for the trail users and maintenance of the common recreation area. Furthermore, this area shall be fenced with split rail fencing. The NGPE shall be subject to the review and approval of the Current Planning Project Manager and the City Attorney, and shall be recorded prior to recording of the Final Plat. 7. The applicant shall submit a detailed final landscape plan for review and approval by the Current Planning Project Manager prior to final PUD approval. The detailed final landscape plan shall include, but is not limited to the following: a. Proposed locations and design details of the pergola/gazebo, split -rail fence and interpretive signage proposed along the soft surface trail. b. Street trees shall be identified within the right-of-way in compliance with the City's street tree standards. c. The plan shall indicate either 100 percent drought tolerant plantings or the applicant shall provide a final irrigation plan with the final detailed landscape plan. d. Provide a revised Landscape Plan indicating a Common Recreation area that is a minimum of 500 square feet that includes improvements providing for recreation by the public and area residents e. Redesign the trail on the south side of Lot 10 such that the trail meanders and is not abutting the edge of the split rail fence on Lot 10. 8. The applicant shall provide a walking path within the right-of-way of South 55th Street that provides for a safe route to the nearest Renton School District bus stop. The path shall be asphalt with a minimum width of 5 feet and separated from the road travel lane by C -curbing as determined by the City's Development Services Division Project Manager. This improvement is required prior to the recording of the plat. City of Renton Community and Economic D menl Department Report to the Hearing Examiner li7LS0.,V PAP 11 PLAT & PUD LVA12-013. ECT. PP. PPLD PUBLIC HEARING DATE: June 12, 2012 Page 30 of 31 9. The applicant shall submit a lighting plan for review and approval by the Current Planning Project Manager prior to construction permit issuance. The lighting plan shall contain pedestrian lighting in addition to building and landscaping lighting if proposed. 10. In the event that Wilson Park I is not constructed and recorded first or not at all, Wilson Park II shall be required to provide appropriate emergency access, per the review and approval of the Development Service Project Manager and the Fire Marshal. This shall be accomplished by providing an acceptable emergency vehicle turnaround, prior to the recording of the plat. 11. The applicant shall establish a home owners' association for the development, which would be responsible for any common improvements, including but not limited to the soft surface trail, landscaping, and park within the PUD. The draft Codes, Covenants & Restrictions (CC&R's) shall be reviewed and approved by the City Attorney, prior to final PUD approval. All common facilities, not dedicated to the City, shall be permanently maintained by the PUD home owners' association. 12. The applicant shall revise the lot width for Lot 1 in order to provide the minimum corner lot width of 60 feet. This shall be shown on the final plat plan. 13. A covenant shall be placed on all tracts restricting their separate sale and giving each lot owner within the plat an undivided interest in the tracts. This covenant should be recorded on the face of the plat, and/or concurrent with the plat recording, noting the recording number on the plat. 14. A street lighting plan shall be submitted with the construction permit application for review and approval by the Plan Reviewer prior to construction permit approval. 15. The applicant shall provide the Current Planning Project Manager, a water line installation plan, which complies with RMC 4-3-050L.8.b.i.(b) for review and approval, prior to final PUD approval. 16. The common boundary between the native growth protection tract and the abutting land must be permanently identified. This identification shall include a permanent wood split rail fence and metal signs on treated or metal posts. The permanent wood split rail fence and signs shall be installed prior to Final Plat recording. 17. The following note shall appear on the face of the Final Plat and shall also be recorded as a covenant running with the land on the title of record for all affected lots on the title: "MAINTENANCE RESPONSIBILITY: All owners of lots created or benefitting from this City action abutting or including a native growth protection tract are responsible for maintenance and protection of the tract. Maintenance includes ensuring that no alterations occur within the tract and that all vegetation remains undisturbed unless the express written authorization of the City has been received." is. On -street parking shall be restricted to one side of Road A, on the east side of the road. No Parking signs shall be installed on the west side, prior to final plat recording. City of Renton C'nnvnundy aril h'conornre .1: WILSON PARK 11 PLAT & P I,'D PUBLIC HEARING DATE: June 12, 20! 2 EXPIRATION PERIODS: Preliminary PUD: Ment Department report to the Hearing Exammer Lf::412-013, F_CF, PP, PPIT) Page 31 of 31 The developer shall, within two (2) years of the effective date of action by the Hearing Examiner to approve the preliminary plan, submit to the Department of Community and Economic Development a final development plan showing the ultimate design and specific details of the proposed planned urban development or the final phase or phases thereof; provided, however, that for a preliminary plan approved concurrent with a preliminary subdivision, the developer shall submit the final development plan within five (5) years of the effective date of action by the Hearing Examiner to approve the preliminary plan. Upon application by the developer, the Hearing Examiner may grant an extension of the approved preliminary plan for a maximum of twelve (12) months. Application for such extension shall be made at least thirty (30) days prior to the expiration date of preliminary plan approval. Only one such extension may be granted for a planned urban development. If a final development plan is not filed within the identified time limits or within the extended time period, if any, the planned urban development preliminary plan shall be deemed to have expired or been abandoned. To activate an expired or abandoned planned urban development, a new application is required. Preliminary Plat: Preliminary plat approval shall lapse unless a final plat based on the preliminary plat, or any phase thereof, is submitted within five (5) years from the date of preliminary plat approval. One one-year extension shall be granted to an applicant who files a written request with the Administrator at least thirty (30) days before the expiration of this five (5) year period, provided the applicant demonstrates that he/she has attempted in good faith to submit the final plat within the five (5) year period. Aaonnau3 .c wnwlo ia x r 3-1IN112i390'8 _ Yy"w r,' it uvaw osmett E ' Z# NHVd NOS1IM ,[ rs_ S2'3 II Irt$ 8330 I a m o qY '' IX] a z s EFl o 0 I i i zeRs a s g w s§ _Lt EXHIBIT 2 N019NINSMM 'fgiN3y hI0.Lt1 21 zf Amrd NOFU 3a lulD arae.- ri j 51I CC iRACi..A. 18.1041/ Q. FEET a 1 uµ' ssar am' e,tssm• Al zeRs a s g w s§ _Lt EXHIBIT 2 N019NINSMM 'fgiN3y hI0.Lt1 21 zf Amrd NOFU 3a lulD arae.- ri AD zeRs a s g w s§ _Lt EXHIBIT 2 N019NINSMM 'fgiN3y hI0.Lt1 21 zf Amrd NOFU 3a lulD arae.- ri OM--% yLL V W AL/ CL M CL r G N r a J a 0 cry EXHIBIT 3 CD - C E o U 2 C a p c EEENa>> a a Z p m d v. In U tt U U 7 V U U u c c n '-a m p_ c ac C m o o EL N 65 2 65 rq TJCi OM--% yLL V W AL/ CL M CL r G N r a J a 0 cry EXHIBIT 3 CD - DEPARTMENT OF COMMUP C` ° AND ECONOMIC DEVELOPMENT ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC MEETING DATE. May 7, 2012 Project Name: Wilson Park 11 Preliminary Plat and Preliminary PUD Owner: Robert Wilson and Doravin Wilson 21VM60' h Street East Lake Tapps, WA 98391 Applicant: Sarre as owner Contact. Darrell Offee, P.E. Offee Engineers, PLLC 13932 SE 159th Place Renton, WA 98058 File Number: LUA122-013, ECF, PP, PPUD Project Manager: Jennifer Henning, Current Planning Manager Project Summary: The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. The site is zoned Residential -14 du/ac (R-14) & Residential -1 du/ac (R-1). The site contains 9,783 s.f. of protected slopes (>40%). Proposed density averages 6A dwelling units per acre across the site, with 9 lots proposed in the R-14 area, & 1 lot proposed within the R-1. A Planned Urban Development is proposed in order to modify minimum lots size within the R-1 Zone and provide larger lots within the R-14 zone. Access would be provided from South 55th Street via new street constructed as part of the approved Wilson Park #1 plat. A small hydrologically isolated, unregulated wetland is located on the western portion of the site. The site contains 82 trees, of which 21 would be removed for the construction of the new street serving Wilson Park #1. Ten (10) trees would be retained, and new trees would be planted including 2 new trees per lot. The project requires Environmental (SEPA) Review, Planned Urban Development (PUD) Review, and Preliminary Plat review. Project Location: 698 South 55`x` Street Exist. Bldg. Area SF: N/A Proposed New Bldg. Area (footprint): N/A Proposed New Bldg. Area (gross): N/A Site Area: 2.15 acres Total Building Area GSF. 93,801 s.f. STAFF Staff Recommends that the Environmental Review Committee issue a RECOMMENDATION: Determination of Non -Significance - Mitigated (DNS -M). EXHIBIT 4 City of Renton Deportment of Communit 'conomic Development Ei )mental Review Committee Report WILSON PARK2 PRELIMINARY PLAT & Pn,.LIMINARY PUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 2 of 11 PART ONE: PROJECT DESCRIPTION / BACKGROUND The applicant proposes to subdivide a 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. The site is zoned Residential -14 dwelling units per acre (R-14) and Residential —1 dwelling unit per acre (R-1). The R-1 portion of the site is considered to be Urban Separator, and as such 50% of the Urban Separator area is required to be dedicated as open space. New residential lots would range in size from 5,559 square feet to 6,778 square feet. The open space tract would be 19,164 s.f. in size. Proposed density averages 6.4 dwelling units per acre across the site, with 9 lots proposed for the portion within the R-14 zone, and 1 residential lot proposed within the R-1 Zone. A Planned Urban Development is proposed in order to modify minimum lots sizes within the R-1 zone and to provide larger lots within the R-14 zone. Access would be provided from South 55th Street via a new street that would be constructed as part of the approved Wilson Park I subdivision (LUA09-140, PP, ECF). The topography of the site slopes upward from the west to the east; an area of steep protected slopes occurs on the eastern portion of the site. Site soils are comprised of Kame Terrace and Ground Moraine which are glacial till soils. Approximately 820 cubic yards of material would be excavated and 11,200 cubic yards of fill would be required to accomplish the project. A small wetland is located on the western portion of the site. This wetland is not regulated per Renton Municipal Code. Of the 82 trees onsite, 21 would be removed for the construction of the new street, 10 would be retained, and new trees would be planted, including 2 new trees per lot. The project requires Environmental (SEPA) Review, Planned Urban Development (PUD) Review, and Preliminary Plat review. 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. The applicant shall comply with the recommendations contained in the Geotechnical Engineering Study, prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012, for the duration of project construction, 2. The applicant shall provide a Temporary Erosion and Sedimentation Plan designed pursuant to the Department of Ecology's Erosion and Sediment Control Requirements outlined in Volume ll ERC Report.doc City of Renton Department of Communit "conomic Development E lmental Review Committee Report WILSON PARK2 PRELIMINARY PLAT & Pn,JMINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 3 of 11 of the 2005 Stormwater Management Manual and provide staff with a Construction Mitigation Plan prior to issuance of construction permits. This mitigation measure shall be subject to review and approval of the Development Services Division. 3. The applicant shall provide weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the Project Engineer of record to the Public Works inspector. 4. Because of moisture -sensitive fine-grained soils mantling the site and the higher gradient areas within the site the geotechnical study recommends that grading and foundation construction be carried out and completed within the dryer period of the year from April 1 through October 31 unless otherwise approved by the Development Services Division. Therefore, the applicant shall adhere to a construction schedule involving grading and foundation work during the dryer period of the year. 5. The applicant shall pay a Parks Mitigation Fee based on $530.76 per each new single family lot prior to recording the final plat. 6. The applicant shall be required to pay a Traffic Mitigation Fee based on $75.00 per each new average daily vehicle trip associated with the proposed project prior to recording of the final plat. 7. The applicant shall be required to pay a Fire Mitigation Fee based on $488.00 per each new single family lot prior to recording the final plat. C. Exhibits Exhibit 1 Zoning Map Exhibit 2 PUD/Plat Map Exhibit 3 Grading Plan Exhibit 4 Drainage/Utilities Plan Exhibit 5 Tree Retention Plan Exhibit 6 Landscape Plan Exhibit 7 Comment Letter (dated April 15, 2012) Exhibit 8 Aerial Photo 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: The subject site is located on a broad moderate to steep westerly -sloping hillside. This downward slope is at grades of 13 to 39 percent. Steeper slopes greater than 40% are located on the eastern portion of the site. The higher gradient portions of the site generally lie within the eastern 100 to 200 feet and the western 150 to 200 feet of the site. Approximately 820 cubic yards ERC Report. doe City of Renton Deportment of Communi :conomic Development E, nmentol Review Committee Report WILSON PARK1 PRELIMINARY PLAT & P,,4LIMINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 4 of 11 of earth material would be cut and approximately 11,200 cubic yards off il I would be imported for the proposal. The applicant submitted a Geotechnical Engineering Study prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012. The report identifies the soils on the site as Kame Terrace deposits underlain by Ground Moraine. Kame Terrace deposits consist mostly of silty sand and gravel to cobble. Locally, they may also contain lenses and pods of till and beds of sand, . silt and clay. According to the Geotechnical Report, these isolated lenses were not encountered on the subject site. Kame Terrace deposits are of moderately -high to high permeability and can provide good foundation support to structure in their native undisturbed state. Ground Moraine deposits are mostly thin ablation till over lodgment till, and were deposited during the retreat of glaciers during the last Ice Age, more than 14,000 years ago. Lodgment till is generally a compact mixture of unsorted clay, silt, sand, gravel and cobble, commonly referred to as "hard pan". Ablation Till is similar to lodgment till, but is much less compact and coherent. Lodgment Till is practically impervious, except local lenses of sand and gravel. It has the character of low-grade concrete and can stand in a steep natural or cut slope for long periods. This soil provides excellent foundation support with little settlement expected. Overlying ablation till is generally looser and is more compressible and permeable. The site contains areas of protected slopes (greater than 40%) in the northeastern portion of the property. This area of protected slopes would be contained within Tract A. There is also a cut slope on the west portion of the property that slopes up to about 6 to 12 feet. This slope likely resulted from the original land grading. Subsurface conditions on the site were explored in November 2004 via six (6) test pits on the western half of the site. The test pits sampled soil at depths ranging from 5.0 to 8.0 feet. The test pits identified a layer of loose, organic topsoil from 1.0 to 2.5 feet thick. The topsoil is generally underlain by a layer of brown Ablation Till soils of loose to medium -dense, silty fine sand, with a trace of gravel and occasional cobble and boulder, about 1.0 to 3.2 feet thick. Underlying the Ablation Till to the depths explored is a Lodgment Till deposit of light -brown to light -gray, dense to - very -dense, weakly -cement, silty fine sand with a trace of gravel. Additional test pits were explored for the eastern half of the site in February 2012. These recent test pits included a layer of loose, organic topsoil, from 8 to 10 inches thick, on the surface. The topsoil is underlain by a layer of brown to light -brown ablation till (weathered till) of medium - dense, silty fine sand, with a trace of to some gravel and occasional cobble and boulder, about 3.5 to 4.0 feet thick. Underlying the Ablation Till to the depths explored is a Lodgment Till (fresh till) deposit of light -brown to light -gray, very -dense, weakly -cement, silty fine sand with some gravel. The soil conditions of added land are generally similar to that of the original land. Both report conclude that the subject site is stable and can support the development provided the recommendations of the November 22, 2004 report are fully implemented and observed during construction. The topsoil and loose to medium -dense weathered soils on-site are of low resistance to erosion. Erosion may occur in the weaker surficial soils over the higher gradient areas if they are devoid of vegetation. Progressive erosion can lead to shallow, skin -type mudflows. The geotechnical report recommends preservation and maintenance of vegetation outside of construction limits to mitigate this potential hazard. The study also recommends that concentrated stormwater should not be discharged uncontrolled onto the ground. Stormwater from impervious surfaces should be ERC Report. doc City of Renton Department of Commun' Economic Development F nmentol Review Committee Report WILSON PARK2 PRELIMINARY PLAT & , _LIMIIVARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page S of 11 captured by underground drain line systems connected to roof downspouts or by catch basins installed in roadways and driveways. Temporary erosion control measures are also recommended and these include: a thin layer of quarry spalls placed over excavated areas to protect the subgrade soils from disturbance by construction traffic; silt fences installed along the downhill sides of construction areas to prevent sediment from being transported onto adjacent properties or streets; and ditches or interceptor trench drains installed on the uphill sides of construction areas to intercept and drain away storm runoff and near -surface groundwater seepage. In order to mitigate for potential geotechnical impacts such as erosion, staff recommends a mitigation measure which requires compliance with the recommendations. contained in the Geotechnical Engineering Study, prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012. Staff also recommends'that the applicant provide a Temporary Erosion and Sedimentation Plan designed pursuant to the Department of Ecology's Erosion and Sediment Control Requirements outlined in Volume II of the 2005 Stormwater Management Manual and provide staff with a Construction Mitigation Plan prior to issuance of construction permits. This mitigation measure shall be subject to review and approval of the Development Services Division. Staff further recommends that weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the Project Engineer of record to the Public Works inspector. Because of moisture -sensitive fine-grained soils mantling the site and the higher gradient areas within the site the geotechnical study recommends that grading and foundation construction be carried out and completed within the dryer period of the year from April 1 through October 31 unless otherwise approved by the Development Services Division. Staff recommends that as a mitigation measure that the applicant adhere to a construction schedule involving grading and foundation work during the dryer period of the year. Mitigation Measures: 1. The applicant shall comply with the recommendations contained in the Geotechnical Engineering Study, prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012, for the duration of project construction. 2. The applicant shall provide a Temporary Erosion and Sedimentation Plan designed pursuant to the Department of Ecology's Erosion and Sediment Control Requirements outlined in Volume II of the 2005 Stormwater Management Manual and provide staff with a Construction Mitigation Plan prior to issuance of construction permits. This mitigation measure shall be subject to review and approval of the Development Services Division. 3. The applicant shall provide weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the Project Engineer of record to the Public Works inspector. 4. Because of moisture -sensitive fine-grained soils mantling the site and the higher gradient areas within the site the geotechnical study recommends that grading and foundation construction be carried out and completed within the dryer period of the year from April 1 through October 31 unless otherwise approved by the Development Services Division. Therefore, the applicant shall adhere to a construction schedule involving grading and foundation work during the dryer period of the year. ERC Report.doc City of Renton Department of Communi =conomic Development E nmento] Review Committee Report WILSON PARK2 PRFLIMINARYPLAT &, ..-LIMINARY PUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 6 of 11 Nexus: SEPA Environmental Regulations 2. Storm Water Impacts: A Technical Information Deport (dated May 5, 2009) was prepared by Baima and Holmberg Inc, for the previous Wilson Park I Plat. An addendum to this report was prepared by 4*K, g on February 28, 2012 to consider the current proposal. The May 2009 report includes an analysis of upstream tributary drainage which states that the parcel to the east drains onto the site, with no problems related to runoff. The Level 1 Downstream Drainage Analysis in the report states that runoff from the site flows west into lots in the adjacent Geneva Court development. The majority of these flows collect in a drain constructed along the back yards of the westernmost lots of the Geneva Court development and then flow into the storm system in South 53rd Place. This flow collects in a stormwater pond/bioswale facility located at the intersection of Talbot Road S and South 53rd Place approximately 750 -feet downstream from the site. This facility outfalls through an 18 -inch pipe to the west side of Talbot Road S into a poorly defined channel flowing into the woods. The flows then pass through a 12 -inch culvert under a walking path and continue to flow west to a wooded wetland area more than a quarter mile downstream from the site. Flows into the ditch along S 55th Street continue west in a rock lined channel along the north side of the street to the intersection of Talbot Road S and S 55th Street. The channel is eroded and shows signs of flowing into the street. Flows from the ditch along Talbot Road S collect in the storm system about 850 -feet downstream from the site eventually flowing into Springbrook Creek at about 1,800 -feet downstream from the site. The Creek continues flowing west to about one-half mile downstream of the site where it enters a box culvert crossing SR 167. The Technical Information Report indicates that there are no apparent drainage problems. The amended February 28, 2012 report evaluates the addition of the subject 10 -lot plat. The original stormwater system for Wilson Park I and located within the street that would serve both Wilson Park I and II was sized to accommodate Wilson Park I lots and the new streets including the access street located within Wilson Park 11. The addendum provides calculations intended to evaluate the sizing of the storm treatment facility for the two projects. The report notes that City of Renton's 2009 Drainage Manual requires Best Management Practices (BMP's) for new developments. One BMP's is to restrict impervious areas on future lots to help reduce runoff, mitigate for development, and minimize the treatment system needed for the project. This is known as a "Restrictive Covenant" provision and was utilized as part of a preliminary sizing of the future system for both Wilson Park I and 11. The applicant intends to utilize the Restrictive Covenant provision and limit impervious surface on each of the new lots in both Wilson Park I and 11 to 3,300 square feet per lot. By limiting the impervious area for homes, patios, driveways and walkways, the proposed stormwater vault will be of an appropriate size to accommodate both developments. The applicant has also intended to develop both plats at the same time. Comments received from surrounding property owners expressed concern as to whether the vault was sized appropriately to accommodate both projects. The applicant has stated that the vault is sized to the 2009 drainage manual and will provide the necessary volume and capacity for both projects. Mitigation Measures: No further mitigation necessary. Nexus: Not applicable. FRC Report. doc City of Renton Department of Communi Economic Development E nmentol Review Committee Report WILSON PARK2 PRELIMINARY PLAT & r —LIMINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 T Page 7 of 11 3. Water (Wetlands) Impacts: The applicant submitted a letter from Altmann Oliver Associates, LLC, dated March 11, 2011, that documents the wetland reconnaissance conducted on the subject property March 1, 2011. The primary focus of the reconnaissance was to verify the results of a wetland determination report prepared by Alder NW (dated October 19, 2004), which indicated the presence of a small less than 800 s.f.) hydrologically isolated wet area in the western portion of the site, immediately adjacent to a remnant foundation of an old loafing shed. The Alder NW report previously indicated that this small wetland area was unregulated as it was significantly disturbed. Altmann Oliver's reconnaissance concurred with the previous findings, describing the wetland as a small Category 3 wetland. Altmann also confirmed that the drainage course flowing from east to west through the southern portion of the site is from an outfall of a storm drain line that collects surface water runoff from South 192nd Street. Therefore, the drainage course is not considered to be stream and is not regulated by City of Renton. Mitigation Measures: No further mitigation required. Nexus: Not applicable. 4. Vegetation Impacts: The applicant submitted a Tree Inventory and Retention Plan and a Tree Retention with the project application. There are 82 total trees on the project site, of which 21 would be removed for construction of the roadway, and 3 trees are within the protected slope area. There are 21 trees within the R-1 zoned area of the site, and 37 trees within the R-14 zoned area. City Code requires that 30% of the trees in the R-1 (or 6.3 trees) and 10% of the trees in the R-14 (3.7 trees) be retained. The applicant is proposing to retain 10 trees and plant street trees and provide enhanced landscaping in the open space tract. The portion of the site zoned R-1 is within the Talbot Urban Separator Overlay. The purpose of the Urban Separator Overlay includes providing a continuous open space and wildlife corridor. The applicant proposes to retain trees within the critical area and buffer, to plant two trees per each new lot, and to enhance Tract A with native and ornamental trees, shrubs and groundcover. The enhancement area will be located proximate to the comparable area within Wilson Park I to provide for the continuous open space corridor. Mitigation Measures: No further mitigation necessary. Nexus: Not Applicable. 5. Parks and Recreation Impacts; It is anticipated that the proposed development would generate future residents who would use City park and recreation facilities and programs. Staff recommends that the applicant be required to pay a Parks Mitigation Fee based on $530.76 per each new single family lot to be payable prior to recording the final plat. The fee is estimated at $5,307.60 (10 new lots x $530.76 5,307.60). Mitigation Measures: 1. The applicant shall pay a Parks Mitigation Fee based on $530.76 per each new single family lot prior to recording the final plat. ERC Report. doc City of Renton Department of Communi Economic Development F )nmental Review Committee Report WILSON PARK2 PRELIMINARYPLA T"& LIMINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 8 of 11 Nexus: SEPA Environmental Regulations; Parks Mitigation Fee Resolution No. 3082, Ordinance No. 4527 4. Transportation Impacts; Access to the site would be from S 55th Street via a 50 -foot wide right-of-way that was identified on an access easement through the subject site for the Wilson Park 1 Plat. The roadway would be constructed to serve both plats (Wilson Park 1 and II) and would be dedicated as a public right-of-way. The roadway will have two 13 -foot wide travel lanes, 8 -foot planter strips on each side, and 5 -foot wide sidewalks. The applicant submitted a Traffic Impact Analysis Report prepared by TraffEx (Northwest Traffic Experts, dated June 23, 2009 and supplemented January 25, 2012). The report indicates that the proposal would utilize the same access to South 55th Street s the approved Wilson Park I Plat. The site access street intersects South 55th Street on the outside of a horizontal curve on South 55th Street to optimize sight distance in both the east and west direction for vehicles entering and exiting the site. The report also indicates that the horizon year for the study is considered to be 2014, as that is the year construction of both plats is anticipated. The study indicated the increase in traffic with the proposal and determined that the traffic would operate at acceptable levels at the intersection of South 55th Street and the new street within the plat. The Level -of -Service (LOS) with the project was determined to be LOS B for future 2014 conditions. Previously, the site distance on South 55th was evaluated as part of Wilson Park I. It was determined then that the City of Renton intersection and stopping sight distance requirements in both the east and west directions would be met. Comments received from surrounding property owners concern the ability of school buses to safely serve the plat. The applicant has observed that presently the Renton School District buses travel east on South 55th in the morning, stopping in South 55th to pick-up students. The buses then travel west in the afternoon, stopping in South 55th to drop-off students. It is anticipated that this practice would continue with the project, and that children would wait together for pick-up. While this is not necessarily a concern for SEPA environmental review; staff will study the issue further and make recommendations to the Hearing Examiner during the Plat and Planned Urban Development Hearing. The proposal would result in an increase in traffic trips to the City's street system. Therefore, staff recommends that the applicant pay a Traffic Mitigation Fee based on a rate of $75.00 per additional average daily vehicle trip. Each new residence is expected to generate 9.57 trips; credit is given for the existing residence on the subject property. The Traffic Mitigation Fee is estimated to be $7,177.50 (10 new lots x 9.57 trips x $75.00 = $7,177.50) and would be payable prior to recording the final plat. Mitigation Measures: 1. The applicant shall be required to pay a Traffic Mitigation Fee based on $75.00 per each new average daily vehicle trip associated with the proposed project prior to recording of the final plat. Nexus: SEPA Environmental Regulations; Transportation Mitigation Fee Resolution No. 3100, Ordinance 4527 ERC Report.doc City of Renton Deportment of Communi =conomie Development E 7mentol Review Committee Report WILSON PARK2 PRELIMINARYPLAT & ...__1MINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 Page 9 of 11 5. Fire & Police Impacts: Fire Prevention staff indicates that sufficient resources exist to furnish services to the proposed development subject to the condition that the applicant provides the required improvements and fees. As the proposal could potentially add 10 new residences, staff recommends that the applicant be required to pay a Fire Mitigation Fee in the amount of $488.00 per each new single family lot. The total fee is estimated to be $4,880.00 (10 new lots X $488.00 4,880.00). Mitigation Measures: 1. The applicant shall be required to pay a Fire Mitigation Fee based on $488.00 per each new single family lot prior to recording the final plat. Nexus: <add Nexus info here> 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 "Advisory Notes to Applicant." Copies of all Review Comments are contained in the Official File and may be attached to this report. Environmental Determination_ Appeal Process: Appeals of the environmental determination must be filed in writing on or before 5:00 PM, May 25, 2012. Renton Municipal Code Section 4-8-110.13 governs appeals to the Hearing Examiner. Appeals must be filed in writing at the City Clerk's office along with the required fee. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall - 7th Floor, 1055 S. Grady Way, Renton WA 98057. ADVISORY (VOTES 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 actions. Planning 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 ERC Report.doc City of Renton Department of Community & Economic Development Environmental Review Committee Report WILSON PARK PRELIMINARY PLAT & I MINARYPUD LUA12-013, PP,PPUD, ECF Report of May 7, 2012 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 between 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 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. 6. 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. Fire Prevention: 1. The Fire Mitigation Fees are applicable at the rate of $488.00 per single family unit. This fee is paid prior to the recording of the plat. 2. 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-feeet of the proposed buildings and two hydrants if the fire flow goes up to 1,500 gpm. Existing hydrants can be counted toward the requirement as long as they meet current code, including 5 -inch storz fittings. 3. Fire Department apparatus access roadways are required to be minimum 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 322 -psi point loading. Access is required within150-feet of all points on the buildings. Maximum grade of 15% is allowed. Dead end streets that exceed 150 -feet in length require an approved turnaround. Plan Review: Water 1. Water service will be provided by Soos Creek Water and Sewer District. A water availability certificate will be required to be submitted to the City with the site plan application. Plan Review: Sanitary Sewer 1. Extension of an 8 -inch sewer main in the new roadway is required. Sewer stubs are required to be provided to each lot. 2. System development fees for sewer are based on the size of the new domestic waters to serve the new homes on the new lots. Sewer fee for a 3/- inch water meter is $1,591.00. Sewer ERC Report.doc Page 10 of 11 City of Renton Deportment of Community & Economic Development WILSON PARK 2 PRELIMINARY PLAT & LIMINARY PUD Report of May 7, 2012 Environmental review Committee Report LUA12-013, PP,PPUD, ECF_ Page 11 of 11 fee for a 1 -inch water meter is $3,977.00. An"approved" water plan from Soos Creek Water and Sewer District will be required to be submitted to the City. Property Services: 1. See attached memo for comments from Property Services. ERC Report.doc DEPARTMENT OF COMMUNITY D City of aANDECONOMICDEVELOPMENT tn ENVIRONMENTAL (SEPA) DETERMINATION OF NON -SIGNIFICANCE MITIGATED (DNS -M) APPLICATION NO(S): LUA12-013, ECF, PP, PPUD APPLICANT: Robert & Doravin Wilson PROJECT NAME: Wilson Park 2 Preliminary Plat & PUD DESCRIPTION OF PROPOSAL: The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. LOCATION OF PROPOSAL: 698S55 th Street 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 4-6-6 Renton Municipal Code. These conditions are necessary to mitigate environmental impacts identified during the environmental review process. Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on May 25, 2012. 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 City of Renton Municipal Code Section 4-8- 110.13. Additional information regarding the appeal process may be obtained from the Renton City Clerk's Office, (425) 430-6510. PUBLICATION DATE: May 11, 2012 DATE OF DECISION- May 7, 2012 SIGNATURES; G-regg-Zimmer, nIministrator-- - - - - Mark Pet rsona Admi strator Public Works D partment Date Fire & Emergency Services Date Terry Higashiyama, Administrator C.E. "Chip" Vincent, Interim Community Services Department Date Administrator/Planning Director Date Department of Community & Economic Development EXHIBIT 5 DEPARTMENT OF COMMUNI1 1 City of AND ECONOMIC DEVELOPMENT] DETERMINATION OF NDN -SIGNIFICANCE -MITIGATED MITIGATION MEASURES APPLICATION NO(S): LUA12-013, ECF, PP, PPUD APPLICANT: Robert & Doravin Wilson PROJECT NAME: Wilson Park 2 Preliminary Plat & PUD DESCRIPTION OF PROPOSAL: The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. LOCATION OF PROPOSAL: LEAD AGENCY: MITIGATION MEASURES: 698S55 th Street The City of Renton Department of Community & Economic Development Planning Division 1. The applicant shall comply with the recommendations contained in the Geotechnical Engineering Study, prepared by Liu & Associates, Inc. dated November 22, 2004 and amended February 15, 2012, for the duration of project construction. 2. The applicant shall provide a Temporary Erosion and Sedimentation Plan designed pursuant to the Department of Ecology's Erosion and Sediment Control Requirements outlined in Volume II of the 2005 Stormwater Management Manual and provide staff with a Construction Mitigation Plan prior to issuance of construction permits. This mitigation measure shall be subject to review and approval of the Development Services Division. 3. The applicant shall provide weekly reports on the status and condition of the erosion control plan with any recommendations of change or revision to maintenance schedules or installation shall be submitted by the Project Engineer of record to the Public Works inspector. 4. Because of moisture -sensitive fine-grained soils mantling the site and the higher gradient areas within the site the geotechnical study recommends that grading and foundation construction be carried out and completed within the dryer period of the year from April 1 through October.3l.unles5.otherwise_approved _. by the Development Services Division. Therefore, the applicant shall adhere to a construction schedule involving grading and foundation work during the dryer period of the year. 5. The applicant shall pay a Parks Mitigation Fee based on $530.76 per each new single family lot prior to recording the final plat. 6. The applicant shall be required to pay a Traffic Mitigation Fee based on $75.00 per each new average daily vehicle trip associated with the proposed project prior to recording of the final plat. 7. The applicant shall be required to pay a Fire Mitigation Fee based on $488.00 per each new single family lot prior to recording the final plat. EXHIBIT 6 ERC Mitigation Measures Page 1 of 1 DEPARTMENT OF COMMUi...: City of A„ . AND ECONOMIC DEVELOPMENT ;r DETERMINATION OF NDN -SIGNIFICANCE -MITIGATED ADVISORY NOTES APPLICATION NO(S): LUA12-013, EGF, PP, PPUD APPLICANT: Robert & Doravin Wilson PROJECT NAME: Wilson Park 2 Preliminary Plat & PUD DESCRIPTION OF PROPOSAL: The applicant proposes to subdivide an existing 2.15 acre parcel into 10 lots for the eventual development of detached single family homes, and 1 tract for open space. LOCATION OF PROPOSAL: 698 S 55”' Street LEAD AGENCY: The City of Renton Department of Community & Economic Development Planning Division Advisory Notes to Applicant: The following notes are supplemental information provided in conjunction with the environmental determination. Because these notes are provided as information only, they are not subject to the appeal process for environmental determinations. Planning: 1. RMC section 4-4-030.0.2 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. Alternafive 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 between 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 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. ERC Advisory Notes Page 1 of 2 6. The applicant shall erect and ,ntain six foot (6') high chain link tem iry 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. Fire Prevention: 1. The Fire Mitigation Fees are applicable at the rate of $488.00 per single family unit. This fee is paid prior to the recording of the plat. 2. 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-feeet of the proposed buildings and two hydrants if the fire flow goes up to 1,500 gpm. Existing hydrants can be counted toward the requirement as long as they meet current code, including 5 -inch storz fittings. 3. Fire Department apparatus access roadways are required to be minimum 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 322 -psi point loading. Access is required within150- feet of all points on the buildings. Maximum grade of 151 is allowed. Dead end streets that exceed 150 -feet in length require an approved turnaround. Plan Review: Water Water service will be provided by Soos Creek Water and Sewer District. A water availability certificate will be required to be submitted to the City with the site plan application. Plan Review: Sanitary Sewer 1. Extension of an 8 -inch sewer main in the new roadway is required. Sewer stubs are required to be provided to each lot. 2. System development fees for sewer are based on the size of the new domestic waters to serve the new homes on the new lots. Sewer fee for a %- inch water meter is $1,591.00. Sewer fee for a 1 -inch water meter is $3,977.00. An"approved" water plan from Soos Creek Water and Sewer District will be required to be submitted to the City. Property Services: 1. See attached memo for comments from Property Services. ERC Advisory Notes Page 2 of 2 1. Gross area of property: 1. square feet 2- Deductions: Certain areas are excluded from density calculations. These include: Public streets" Private access easements** Critical Areas* Total excluded area: 3. Subtract line 2 from lime I for net area 4. Divide line 3 by 43,560 for net acreage 5- Number of dwelling units or lots planned 6. Divide line 5 by line 4 for net density: Wq " square feet square feet square feet 2. square feet 3. square feet 4. acres 5. unitsllots 7] 6. = dwelling units/acre Critical Areas are defined as "Areas determined by the City to be not suitable for development and which are subject to the City's Critical Areas Regulations including very high landslide areas, protected slopes, wetlands or floodways." Critical areas buffers are not deductedlexcluded. Alleys (public or private) do not have to be excluded. http:IlrentDntiVU.gavluploadedFilesIBusinessfPBPWIDEVSCRViFORMS_PLANNING/density.doc - l - 03108 EXHIBIT 7 DENSITY ia, WORKSHEET City of Renton Planning Division' 1055 South Grady Way -Renton, WA 98057 Phone: 425-430-7200 Fax: 425-430-7231 1. Gross area of property: 1. square feet 2- Deductions: Certain areas are excluded from density calculations. These include: Public streets" Private access easements** Critical Areas* Total excluded area: 3. Subtract line 2 from lime I for net area 4. Divide line 3 by 43,560 for net acreage 5- Number of dwelling units or lots planned 6. Divide line 5 by line 4 for net density: Wq " square feet square feet square feet 2. square feet 3. square feet 4. acres 5. unitsllots 7] 6. = dwelling units/acre Critical Areas are defined as "Areas determined by the City to be not suitable for development and which are subject to the City's Critical Areas Regulations including very high landslide areas, protected slopes, wetlands or floodways." Critical areas buffers are not deductedlexcluded. Alleys (public or private) do not have to be excluded. http:IlrentDntiVU.gavluploadedFilesIBusinessfPBPWIDEVSCRViFORMS_PLANNING/density.doc - l - 03108 EXHIBIT 7 City. of f- Department of Community and Economic Development Planning Division ADMINISTRATIVE POLICY/CODE INTERPRETATION MUNICIPAL CODE SECTIONS: RMC 4-9-150.3.b Planned Urban Development Regulations REFERENCE: Determination regarding calculation of residential density for projects with multiple zoning classifications when proposed as part of a Planned Urban Development. SUBJECT: Wilson Park 2 Planned Urban Development and Preliminary Plat (LUA12- 013, PP, PPUD) BACKGROUND: The City is evaluating an application for the second phase of a proposed plat and Planned Urban Development on a site that is zoned both R-14 and R-1. The site includes a portion of the Talbot Urban Separator, an overlay intended to protect resources and environmentally sensitive areas, to create contiguous open space corridors within and between urban communities, which provide environmental, visual, recreational and wildlife benefits. Individual properties within the Urban Separator often have multiple zoning classifications, where zoning boundaries do not necessarily coincide with property lines as is usually the case with zoning. Rather, the zoning district boundaries are based on the City's understanding of the location of environmentally critical areas on the site, at the time the zoning was assigned to the site. In the Talbot Urban Separator area, properties have multiple zoning classifications: R-1, R-8, and R-14. The R-1 zone allows for density to be determined density based on gross site area. All other residential zoning classifications require that density be determined based on net density where critical areas, access easements and dedicated roadways are deducted. Applying density based on zoning boundary lines for a property with multiple zones, could result in a project that does not recognize the developable area of the site, and concentrates density inappropriately, or restricts density inappropriately on the site. Applicants have the ability to pursue a Planned Urban Development in order to depart from certain development standards such as lot size; however the PUD does not allow the number of dwelling units to exceed the density allowances of the base zone. The proposed determination would not result in density of the base or overlay zone to be exceeded. H:\CED\Planning\Title IV\Docket\Administrative Policy Code Interpretation\0-30\Code Interpretation -do( EXHIBIT 8 Rather, it would clarify that the density can be averaged across the site, provided this is accomplished as part of a PUD. JUSTIFICATION: Sites with multiple zoning designations should be allowed to average the density across the site, through the Planned Unit Development process. Maximum density could not be exceeded. This determination is to clarify process. DECISION: Properties with more than one zoning classification will be allowed to average residential density across the site provided this is accomplished through the Planned Urban Development process. INTERIM ADMINISTRATOR/ PLANNING DIRECTOR APPROVAL: C. E. "Chip" Vincent DATE: May 30, 2012 APPEAL PROCESS: To appeal this determination, a written appeal --accompanied by the required filing fee --must be filed with the City's Hearing Examiner (1055 South Grady Way, Renton, WA 98057, 425-430-6515) no more than 14 days from the date of this decision. Your submittal should explain the basis for the appeal. Section 4-8-110 of the Renton Municipal Code provides further information on the appeal process. CODE AMENDMENTS NEEDED TO IMPLEMENT DETERMINATIONS: RMC 4-9-150.3.b should be amended to read as shown on Attachment A. CI -30 Page 2 of 2 Attachment A 4-9-150 PLANNED URBAN DEVELOPMENT REGULATIONS: 3. Code Provisions Restricted from Modification: a. Permitted Uses: A planned urban development may not authorize uses that are inconsistent with those uses allowed by the underlying zone, or overlay district, or other location restriction in RMC Title 4, including, but not limited to: RMC 4-2-010 to 4-2-080;4-3-010 to 4-3-040, 4-3-090, 4-3-095, and 4-4-010. b. Density/Permitted Number of Dwelling Units: The number of dwellings units shall not exceed the density allowances of the applicable base or overlay`zone or bonus aria in chapter 44=2 or 449 RMC; however, averaging of density across a'sife with multiple zoning classifications may be proposed: - c. Planned Urban Development Regulations: The City may -not modify any of the provisions of this Section, Planned Urban Developriten. t-RegE lations; d. Procedures: The City may not mod°fy sny of-1-hik*ocedural 'provisions of RMC Title 4, including, but not limited to, fees, submittal requirements, and btherstmilar provisions found in chapters 44=1, 4=7, 4-8 and 4 9 RMC, and ' ., a e_ Specific Limitations The City_.ynay not modify any provision of RMC 4-3-050, Critical Areas Regulatioft, 4,3-090, Shoreluidii, Ma. s,Program Regulations, 4-4-130, Tree Cutting and Land Clearing, 4 4 ;:Grading, Excavation and Mining Regulations, chapter 44=5 RMC, or RMC 4-6-010 fo 4-6-050 and 44-610 fihrougli." i 110 related to utilities and concurrency, except that provisions may be altered for these:eodes byalfernates, modification, conditional use, or variance as specificaNyallowed in the `referenced Chapter or Section. Such alternates, modification, conditional use, or variance applications may be merged with the consideration of a planned urban development peT C 4-9-150-L (Ord. 4351, 5-41992; Amd. Ord. 5153, 9-26-2005) aw u7 w Z C7CV a_ 2ua 0H M Z 0 U LU0 LL0 LU w wiF O Z a a 9'd9dd0'tl m S2O3lr ONO IMO h n ryID mY_hNNN i=- aNaN ww w 60 444 4 C(r Pi Piukuc4i c4i b''ii It --------- w — - - m• . wrywryR n I JOLLWII 21181 NOSIIM 1213908 1 a t Z#)NVd NOSTAA R Q Na _ 0- 4 m - iF Z 1n _`meg ED J Lo h \ t} = X14 ti a r_ Y - ' TREES -IQ-BF- FOR R/v IMPRVq EHEN------------ - TYPICAL) - _\ i o Lnz EXHIBIT 9 ytic/ yrp ig No sv3tl 'ON WDM o N3a niosr x — awolno if mvd rvosuM 0 A113 LUclo" P, City a,Renton TREE RETENTION WORKSHEET 1. Total number of trees over 6" in diameter' on project site: 1. ??- trees 2. Deductions: Certain trees are excluded from the retention calculation: Trees that are dead, diseased or dangerousz -r' trees Trees in proposed public streets _7A trees Trees in proposed private access easements/tracts trees Trees in critical areas3 and buffers trees Total number of excluded trees: 2. Z trees 3. Subtract line 2 from line 'i: 3. j -V trees 4. Next, to determine the number of trees that must be retained¢, multiply line 3 by: 0.3 in zones RC, R-1, R-4, or R-8 9,-1 Z t " ?f D - -22 0.1 in all other residential zones 9.14 !err VVW J 0 , I z 0.05 in all commercial and industrial zones 4. 1 trees 5. List the number of 6" or larger trees that you are proposing to retain: 5. 10 trees 6. Subtract line 5 from line 4 for trees to be replaced: 6. trees If line 6 is less than zero, stop here. No replacement trees are required). 7. Multiply line 6 by 12" for number of required replacement inches: 7. C/ inches 8. Proposed size of trees to meet additional planting requirement: Minimum 2" caliper trees required) 8. LZ inches per tree 9. Divide line 7 by line 8 for number of replacement trees6: if remainder is .5 or greater, round up to the next whole number) 9. trees 1 Measured at chest height 2. Dead, diseased or dangerous trees must be certified as such by a forester, registered landscape architect, or certified arborist, and approved by the City, s_ Critical Areas, such as wetlands, streams, floodplains and protected slopes, are defined in Section 4-3-050 of the Renton Municipal Code (RMC). Count only those trees to be retained outside of critical areas and buffers. s. The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMG 44-130117a Inches of street trees, inches of trees added to critical areas/buffers, and inches of trees retained on site that are less than 6" but are greater than 2" can be used to meet the tree replae----- http://rcntonwa.gov/uplaadedFilesBusinessfPHPWIDEVS£RVIFORMS_PLANNiNGrrr=Ret EXHIBIT 10 NOlSRVIHSW 'NOIN2W Y ` so3a ossb JZegQ une 6 N'dld cd ld'1 — .? l! P i ie n•a •.n.wa a i gE 411 Im 1 I r I! rr E r H+ i0'88Z 3„gfi,8S.00N EXHIBIT 11 WILSON PARK PLAT "(°tRento, TRAFFIC IMPACT ANALYSIS nrrr9 Division CITY OF RENTON 200,c ftce#veo Prepared for Mr. Robert Wilson 21703601h St. E. Lake Tapps, WA 98391 Prepared by IV OR THWES T TPAFFlc EXPERTS 11410 NE 124"! St., #590 Kirkland, Washington 98034 Telephone: 425.522.4118 Fax: 425.522.4311 June 23, 2009 TIS o ' e 5 e,-6 tA d p avl C V EXHIBIT 12,; rraffZ&( iYDRTh FT TRAFFIC EXPERTS 1141011' 1eyth SI., #590 KirWa.gd, VA 95034 Phom. 425.522.41 18 Fax 425.522.4811 June 23, 2009 Mr. Robert Wilson 21703 60" St_ E. Lake Tapps, WA 98391 Re: Wilson Park Short Plat - City of Renton Traffic Impact Analysis Dear Mr. Wilson: We are pleased to present this traffic impact analysis report for the proposed 14 lot Wilson Park Residential short plat located at the 720 S. 55"' St. in the City of Renton. The scope of this analysis is based upon the preliminary plat site plan, the Ci of Renton Policy Guidelines for Traffic Impact Analysis for New Development, and conversations with City Renton staff. Our summary, conclusions and recommendations begin on page seven of this report. PROJECT DESCRIPTION Figure 9 is a vicinity map showing the location of the site and study area. Figure 2 is a close in area map showing the site location and surrounding street network. Figure 3 shows the preliminary site plan. The primary access street runs from the southwest corner of the site to S 55th St. through a 50 ft. wide easement on the parcel adjacent to the south side of the site. The primary access from S. 55"' St. to the site is 28 ft. wide with a sidewalk on the west side of the street. A secondary gated emergency vehicle access connects to S 551' St. though a 30 ft. easement. Streets within the site will be 32 ft. wide with a sidewalk on one side. The primary site access street is located on the outside of a horizontal curve on S 55t" St. to optimize sight distance in both east and west directions for vehicles exiting the site. Page i Wilson Park ?raffmy Development of the Wilson Park plat is expected to occur by the year 2011. Therefore, for purposes of this study, 2011 is used as the horizon year for this study. An existing single family home within the project site will be removed with this development. TRIP GENERATION AND DISTRIBUTION The 14 single-family units in the proposed Wilson Park 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 Trips TotalTripsperunitEnteringExiting 67 157 Average Weekday 9.57 134 50% 50% AM Peak Hour 0.75 8 1125% 75% PM Peak Hour 1.01 5 14639370 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, Eighth 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. Figure 4 shows the estimated trip distribution and the calculated site -generated traffic volumes_ The distribution is based on existing traffic volume patterns, the characteristics of the road network, the location of likely trip origins and destinations employment, shopping, social and recreational opportunities), expected travel times, and previous traffic studies. Page 2 Tra EXISTING PHYSICAL CONDITIONS Street Facilities Figure 5 shows existing traffic control, number of street lanes and other pertinent information. The streets in the study area are classified per the City of Renton Comprehensive Pian as follows: Talbot Rd. S Collector Arterial S 55th St. Local Access 98th Ave S Local access 98th Pi. S Local access 102nd Ave S Local access S 55th St. consists of two 11 ft. lanes and a shoulder that varies in width from approximately two to four feet in the vicinity of the project site. A section of S 55th St. east of the project site consists of several sharp curves and is posted with a 15 mph advisory speed sign and with chevron arrows at each curve within the section. There is a left turn pocket on S 55th St. at 98th Ave. S, approximately 125 ft. west of the Wilson Park site access street. EXISTING TRAFFIC CONDITIONS Traffic Volumes Figure 6 shows existing, future without project and future with project PM peak hour traffic volumes at the proposed site access street/S 55t' St. intersection. The proposal generates less than 30 PM peak Dour trips and no other intersection or street segment in the City of Renton will experience an increase of 5% in traffic volumes due to this development. Therefore, only the site access street/S 55ffi St. intersection requires a level of service (LOS) analysis per the Ci of Renton Policy Guidelines for Traffic Impact Analysis for New Development. A PM peak hour traffic count was performed on Tuesday, .lune 16, 2509 and is included in the Technical Appendix. Level of Service Analysis Level of Service (LOS) is a qualitative measure describing operational conditions within a traffic flow, and the perception of these conditions by drivers or passengers. These conditions include factors such as speed, delay, travel time, freedom to maneuver, traffic interruptions, comfort, convenience, and safety. Levels of service are given letter designations, from A to F, with LOS A representing the best operating conditions (free flow, little delay) and LOS F the worst (congestion, long delays). Page 3 Wilson Park Tra Generally, LOS A and B are high, LOS C and D are moderate and LOS E and F are low. Table 1 shows calculated level of service (LOS) for future conditions including project traffic at the pertinent street intersection. The LOS was calculated using the procedures in the Transportation Research Board Highway Capacity Manual 2000. The LOS shown indicates overall intersection operation. At intersections, LOS is determined by the calculated average control delay per vehicle. The LOS and corresponding average control delay in seconds are as follows; TYPE OF INTERSECTION A B C D E F Signalized 9 0. X10.0 and X20.0 and 35.0 and 55.0 and 80. 0 20.0 35.0 55.0 80.0 0 Stop Sign Control 1 0 . 10 and <15 15 and 525 f 25 and <35 35 and X50 50 Accident History Historical accident data for the section of S. 55"' St. between the intersections 98t" Ave. S and 99t" PI S was obtained from the City of Renton. A total of 4 accidents occurred from January 1, 2004 through December 31st 2008. Three accidents occurred on the street section between the intersections, one accident occurred at 99"' PI S and no accidents occurred at 98tf' Ave. South. Two of the accidents were injury type accidents with one being a fatality, The fatality was a single vehicle travelling in the westbound direction approximately 319 ft west of 99"' Pl. South. None of the accidents occurred at the curve on S. 55"' St. where the site access street is proposed to be located. Based on the field review and historical accident data there are no readily apparent safety issues that should result from the proposed development. The historical accident data is included in the technical appendix. FUTURE TRAFFIC CONDITIONS (WITHOUT THE PROJECT Figure 6 shows projected 2011 PM peak hour traffic volumes without the project_ These volumes include the existing traffic volume counts plus background traffic growth. The background growth factor accounts for traffic volumes generated from other approved but unbuilt subdivisions and general growth in traffic traveling through the area. A 3% per year annual background growth rate was added for each year of the two year time period from the 2009 traffic count to the 2011 horizon year of the Page 4 Wilson Park rraffmy proposal. Cit of Renton historical traffic count data supports the 3% per year growth rate on S. 55 Street. FUTURE TRAFFIC CONDITIONS WITH PROJECT Figure 6 shows the projected future 2011 PM peak hour traffic volumes with the proposed project. The site -generated PM peak hour traffic volumes shown on Figure 4 were added to the projected future without project volumes to obtain the future with project volumes. Table 1 shows calculated LOS for future with project volumes at the Wilson Park site access street/S. 55th St. intersection. The study intersection operates at an excellent LOS A for future 2011 conditions including project -generated traffic. SIGHT DISTANCE EVALUATION Sight distance on S 55th St. is excellent looking to the west from the proposed site access street and extends approximately 785 ft. to Talbot Rd. South. Sight distance to the east is limited by a horizontal curve on S 55u' Street. This curve has a posted advisory speed of 15 mph. In evaluating sight distance, the generally accepted rule is to add 5 mph to the posted speed to determine the design speed of the street. Sight distance requirements looking to the east from the Wilson Park site access street are therefore based on a 20 mph design speed for the horizontal curve on S 55th Street. Intersection sight distances and stopping sight distances were measured and compared to City requirements at the Wilson Park site access street/ S 55th St. intersection. City of Renton is requirements are based on current AASHTO "Geometric Design of Highways and Streets" standards. Intersection Sight Distance AASHTO standards for a 20 mph design speed require an intersection sight distance of 145 ft. looking to the left (east) from the site access street (using an eye height of 3.5 ft. and a vehicle height of 4.25 ft.). Attached in the technical appendix are Exhibits 9-55 and 9.58 showing the current AASHTO standards for intersection sight distance. A right tuming vehicle exiting from the side street is required to enter the westbound lane and accelerate to 85% of the design speed so as not to interfere with the traffic flow. The field measured intersection sight distance looking to left (east) from the site access street is 215 ft. thus exceeding the AASHTO required 145 feet. Intersection sight distance looking to the right from the site access street is excellent and extends all the way to Talbot Rd. S at approximately 785 ft. Page 5 Wilson Park lrrafmf Stopping Sight Distance Stopping sight distance is the distance traveled while the vehicle driver perceives a situation requiring a stop, realizes that stopping is necessary, applies the brake, and comes to a stop. A stopping sight distance of 115 ft. is required for a 20 mph design speed (using an eye height of 3.5 ft. and an object height of 2 ft.). Attached in the technical appendix is Exhibit 3-1 showing the current AASHTO standards for stopping sight distance. There is an approximate 10% downgrade in the westbound direction on S 55h Street_ The required stopping sight distance is therefore increased an additional 40 ft. to account for a 10% downgrade with a 20 mph design speed. The required westbound stopping sight distance therefore is 115 + 40 = 155 feet. The field measured westbound stopping sight distance is 197 ft. thus exceeding the required 155 feet. Stopping sight distance for eastbound vehicles on S. 55th St. is excellent and extends from Talbot Rd. S. approximately 785 feet to the site access street. The City of Renton AASHTO based intersection and stopping sight distance requirements are met at the Wilson Park site access street/ S 55th St. intersection in both the east and west directions. TRAFFIC MITIGATION REQUIREMENTS The City of Renton requires a Transportation Mitigation Fee payment of $75 per new daily trip attributed to new development. One existing single family home on site will be removed. with this development resulting in a net increase of 13 single family homes. The net new daily trips due to this development are 124 trips (13units x 9.57 daily trips per unit). The estimated Transportation Mitigation Impact Fee is $9,300 (124 daily trips X $75 per daily trip). Page 6 M1 rk SUMMARY, CONCLUSIONS AND RECOMMENDATIONS We recommend that the Wilson Park Plat be constructed as shown on the site plan with the following traffic impact mitigation measures: Construct the street improvements including curb, gutter and sidewalk for site access street and intemal site streets as shown on the site pian. Contribute the approximately $9,300 Transportation Mitigation fee to the City of Renton. No other traffic mitigation should be necessary. If you have any questions, please call 425-522-4118. You may also contact us Via e-mail at vinoe nwtraffex_eom or IarNCab_nwtrafFex.com. Very truly yours, Vincent J. Geglia Principal TraffEx Page 7 C AL. j-1 ate. 3-a Larry D. Hobbs, P.E. Principal TraffEx TABLE 1 PM PEAK HOUR LEVEL OF SERVICE SUMMARY WILSON PARK PLAT TRAFFIC IMPACT ANALYSIS INTERSECTION EXISTING 2009I VW THOTUT PROJECT Site Access St/S 55h St. I NA I NA I SB (A 9.9) Number shown is the average control delay in seconds per vehicle for the worst approach or movement which determines the LOS for an unsignalized intersection per the Transportation Research Board Highway Capacity Manual 2000 XX) LOS and average control delay for the worst approach or movement at an unsignalized intersection SB) southbound approach Page 8 S1 t9i I I L rraffe-Z vZ7jqrHWE*S7- TRA FFIC EXF"ERT.5 C. a -.. .. .+_ x_11i= ST PL it LO PIL k LJ fop M-11 Pra*et Sfite__ _ , Wilson Park Plat - City of Renton Vicinity Map Figure 1 f T 1 II 1 {e /VOLT NW—S7- 1 , i Y•xY ^ r . .r if7A FF1G EXPE"f2TS• a. 557 i:T• : " qtr---5 i83Tr..T'^" f., ri Y=f' Nwtl Of mn s • _. - + T i NOV 17 6Gr W, If Ar . Wilson Park Plat - City of Renton Area Map Figure Z s 4 y 1 Ar . Wilson Park Plat - City of Renton Area Map Figure Z 9I ixay 5,'6" ?£cam. t :wF III ii7i `"All-n I 1 1 ! f KY LIIp M1 s01CIQ,W [is J.SS• Al 9Is S Ait4 NOT Maw 71 I: ! Ir 1 j --- -} r- v 11164---1 k t2 M1 yf•tsl Z_ as _l " rl - - Y _ J 4. a _ _ L _:" J I '' ^. 9 , :• i I i ,ry a -ax is;#/ i - - a ! ]ra]os=nl3 >: 4: !' \\ I _ r I1r51' fin -o° -- - - - - - - ,> or'. ' - , 5 I a(55' t : ar., I. IJ t 1• a(F ur toKF 4•]R l lYH S} p ' i C . r- _ _ _ _ _ _ ` Lin ' r - drySAva6. lA I «SI IrII r 3 I' 1063 rlL S Iae..Y N7', S u}' I Y U lR ftf :1 p a I 14Nrtrf 9F 1 re]-ef 1 X • r+.mar* ' / tarl[T tette m xaeaerftauau I r I o' 1 L ' ., _ uxzsc 1aRt]!}_WS-9119 ws x : fit f if II I ' -j I 1 ,` r%'F '' r wAm" Sa f am -QS o i I `Y. F.T;f 1 . 12W I y I ] Yr a SIB Ajoy 11 316 +3 lFdJ a2 ~ T a IBJ mar .b"E onfew COM" mmulwar am m rur rnr s elnr-ul ` I. ,, If ' E77 aFC nu'E7ffa+Kareu9 \ Li Wfi (177f aY L91rLl MM 0 1n tom o SE S Wilson Park Plat - City of Renton Figure Site Plan 1 3 i 65% t 79% 3 yT S;STy ;T 4 t 14% T S 14 f,1 ST 7.s `k- 2 0-0- 0 PM Peak Hour Traffic Volume Enter 9 Exit 5 Total 14 Wilson Park Plat - City of Renton PM Peak Hour Trip Generation and Distribution rra`. 7'f2AFFIG EXPERTS sz 19C{ f V SE t97-1 ST 7% 14% 3 S-.- i92,e1- ST 4 Legend 15% Percentage of Project Traffic 3 PM Peak Hour Traffic Volume Figure 4 Wilson Park Plat - City of Renton Figure Existing Conditions - 5 Legend 2 Lanes Number of travel lanes 25 mph Speed Limit Stop Sign Control r-- NpR r,YwE3T TRAFFIC' EXPERTS n a'r 197T.i 5T d SE TWDO ST S Spar_ S V S 6 E C J 3r3 N N l!7 N 2 Lanes 2 Lanes 2 Cartes 4 sr s ssT., s -r 15 mph T 25 mph 25 mph ECL EJ lf N N N co a T F Wilson Park Plat - City of Renton Figure Existing Conditions - 5 Legend 2 Lanes Number of travel lanes 25 mph Speed Limit Stop Sign Control Advisory Speed Sign Wilson Park Plat - City of Renton Figure Existing Conditions - 5 I ta"na ST s SSTH sT S?T•. "sl i Future Future Without With Existing Project Project CD 0 p - 0J ti d 466-0`121 e Accessi S 55th St CD C) 6 JJ 1%- 4 494-0-128 I Site Access! S 55th S! JVORrt>'WEST TATA FFlC EXPEP TS l93T•i ! T r 7 2 494-0`128 e Access! S 55th S t SZ: 1907• i —r S; t'V-e2 ;r Wilson Park Plat - City of Renton Figure PM Peak Hour Volumes for Existing and Future Conditions 6 Preps C. Nr' Tex Traf -c Count Consultants, Inc. Phone: (425) 861-8866 FAX: (425) 861.8877 F -Mail: TMincigaol.com WBEfDBE Intersection: 9Bth Ave S @ S 55th St Date of Count: Tues 6116!09 Location: Renton Checked By: LBP T me From North on (SB) From South on (NI3) From Easton (WB) From West on (EB) Interval Interval 98th Ave S 96th Ave S S 5th St S 5th St Total Ending at T L S R T L S R T L S R T L I5 R 4:15 P 0 0 0 0 0 1 0 1 0 2 29 0 0 0 66 1 1 122 4:30 P 0 0 0 0 0 0 0 0 1 1 24 0 1 0 771 103 4745 P 0 0 0 0 0 0 0 2 0 1 32 0 0 0 109 0 144 5:00 P 0 0 0 6 0 0 0 1 0 0 34 0 0 0 124 1 160 5:15P 0 0 0 0 0 0 0 0 0 0 17 0 0 0 116 3 138 5:30 P 0 0 0 0 0 2 0 0 0 1 36 0 0 0 112 0 151 5:45 P 0 0 0 0 0 1 0 1 0 1 23 0 0 0 106 1 135 6:00 P 0 0 0 0 0 0 0 0 0 0 29 0 0 0 60 1 110 6:15P 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SM IF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6:45P 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7:00P Otto 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Total Survey0 0 0 0 0 2 0 01. 0 0 4 D 5 1 6 224 1 0FToTsir, HV r0a rda B 1063 0.0% Peak Hour. 4:30 PM to 5.30 PM Total0 0 0 0 0 2 0 3 0 2 119 0 0 463 1 4 593 Iproach 0 5 121 467 593 HV r0a rda Ma NO 0.0% PHF nia 0.63 0.82 0.93 0.93 K •tram: INT 91 INT 02 INT D3 INT D4 INT 05 INT 06 INT 07 INT 08 INT 09 NT i0 MT 11 INT 12 S 5th St 121 I Peds 0 Bike! J . ssa a67 N S E w No Peds 01 0 01 0 i a_: 4:30 PM to 5:30 PM 4 ......... Ped' +_ 4 _ [ 0 Bikef _p __1 E 0 0 0 0 0 0 0 98th Ave S 0 Bleyciss From: N S E 0 INT 01 0 fNT 02 0 INT 03 0 INT D4 0 INT 05 0 INT 06 INT 07 INT 06 2 0 Special Notes: 0 0 0 0 0 0 2 0 2 s 5th St 119 121 2 1 587 I 0 IBike Ped 3 fi4D 1.0 PHFPeuk Hour Volume PHF %HV EB 093 nla Check WB 0.82 n/a In. 593 NB 0.63 nla Got: 593 SB n1s nla Intersection 0.93 0.0% 0 Special Notes: 0 0 0 0 0 0 2 0 2 f b '1;r10 J9 L3-55 PAX 424 3:10 7376 W t- 0 fl RENTON TRANS- SYS T 0 a f; m u i.J rV S c J n L:. 4V v u r 0 a f; m u i.J rV S c L 0 a f; C-1 C o CJ r v v f, U3 rr 4 7 L' w CW C C'- i e v 3 1 G Z. 0 a f; Imz2onB „:5§ F. Jn ;376 RE\ TRANS. Sys. T s u ^ r * ml j Q § p e V3 Q S a c 9 j E d $ b a r 3 4 k m 0o; TWO WAY STOP CONTROL SUMMARY jeneral information ite Informati, Analyst Intersection Agency/Co. urisdiction Renton Date Performed 6119/2009 Analysis Year 2011 Future with Project Analysis Time Period M eak 1ro'ect Description astlWest Street: S 55th St North/South Street: Site Access St ct' n Orientation• East-West Stud Period hrs : 0.25terse10 Vehicle Volumes and Adjustments Major Street Eastbound Westbound Movement 1 2 3 4 5 B L T R L T R Volume 7 494 0 0 128 2 eak-Hour Factor, PHF iourly Flow Rate, HFR 0.93 1 7 0.93 531 0.93 0 0.93 0 0.93 137 0.93 2 ercent Heavy Vehicles 0 0 Vledian Type Undivided ZT Channelized 0 0 anes 0 1 0 0 1 0 onfiguration LT TR J stream Si nal 0 0 Minor Street Northbound Southbound Movement 7 L 8 T 9 R. 10 L 11 T 12 R Joiume 0 0 0 1 0 4 eak-Hour Factor, PHF 0.93 0.93 0.93 0.93 0.93 0.93 iourly Flow Rate, HFR 0 0 0 1 1 0 1 4 Dercent Heavy Vehicles 0 0 0 0 0 0 Dercent Grade (%) 0 0 cared Approach N N Storage 1 0 0 RT Channelized 0 0 anes 0 0 0 0 0 0 onfiguration LR 3ela , Queue Length, and Level of Service pproach EB WB Northbound Southbound Movement 1 4 7 8 9 10 11 12 ane Configuration LT LR vph) 7 5 m) (vph) 1457 738 0.00 0.01 15% queue length 0.01 0.02 ontrol Delay 7.5 0.9 OS A A 4pproach Delay 9.9 4pproach LOS A rcS2000'1im Copyright C 2000 University of Florida, All Rights Reserved Version 4.1 AASHTD--Geometric Dej!A ighways and Streets Time gap (a) at design spud of Desi n vehicle ma r read Passenger car 6.5 Single -unit truck 8.5 Commination truck 1015 Note: Time gaps are for a stopped vehicle- to turn right onto or cross a two-lane highway with no median and grades 3 percent or less. The table values require adjustment as follows: For multilane highways: For crossing a major road with more than two lanes, anti 0.5 seconds for passenger cars and 0.7 seconds for trucks for each additional lane to be crossed and for narrow medians that cannot store the design vehicle. For minor road approach grades: If the approach grade is an upgrade that exceeds 3 percent, add 0.1 seconds for each percent grade. ExWbit 9-57. Time Gap for Case B2, -Right Turn from Stop and Case B3 -,-Crossing Maneuver Note: iratarsection sight distance shown is for a stopped passenger car to tum right onto or crass a two-lane highway with no median and grades 3 percent or less.' For other conditions, the time gap must be adjusted and required sight distance recalouiatsd. ambit 9-58. Design Intersection Sight once ---Case gam --Right Turn from Stop and Case W-Ccossing Maneuver M Metric- lus Custal1l) Y Intersection sight Intersection sight Stopp€ng distance for Stopping distance for Design sight_ passenger cars Design sight Essen er cars speed distance Calculated Design speed distance Calculated Design tmlh m rn rn h it ft t 20 20 36.1 40 15 80 143.3 145 30 35 54.2 55 20 115 191.1 195 40 5o 72.3 7S 25 15.5 _ 236,9 240 50 65 90.4 95 30:. .. 204 286.7 290 60 85 1 fi8.4 110 250 334.4 335 70 105 126.5 130 35 40 . 305 362.2- 385 80 130 144.6 145 45 360 430.0 434 S0 160 162.6 165 50 4:25 477.8 480 100 185 180.7 185 55 495 525.5 530 110 220 198.8 200 60 570... 573.3 575 120- 259 216.6 220 65 645 621.1 625 130 285 234.9 2- 5 70 730 668.9 670 75 820' 716.6 720 80.. 910 764.4 765. Note: iratarsection sight distance shown is for a stopped passenger car to tum right onto or crass a two-lane highway with no median and grades 3 percent or less.' For other conditions, the time gap must be adjusted and required sight distance recalouiatsd. ambit 9-58. Design Intersection Sight once ---Case gam --Right Turn from Stop and Case W-Ccossing Maneuver M Irttersecrfons Note. Intersection sight distance shown is for a stopped passenger car to tram left onto a two-lane highway with no median and grades 3 percent or less. For other conditions, the time gap rntW be adjusted and required sight distance recalculated. Exhibit 9-55. Design Intersection Sight Dist nce-_4 me BI—Left Tura From Stop Sight distance design for left turns. at divided -highway intersections ghould consider multiple design vdhicles and median width. If the design vehicle used to determine sight distance for a divided -highway intersection is larger than a passenger car, then sight distance for left turns will need to be checked for that selected design vehicle and for smaller design vehicles as well. If the divided -highway median is wide enough to stare the design vehicle with a clew%nce to the through lanes of approximately I m (3 ft] at both ends of the vehicle, no separate analysis for the departure sight triangle for Ieft turns is needed on the minor -road approach'for the near roadway to the left. In most cases, the depart= -sight triangle for right turns (Case 132) will provide sufficient sight distance for a passenger car to cross the .near roadway to reach the median. Possible exceptions are addressed in the discussion of Case B3. If the design vehicle can be std in the median with adequate clearance to the through lanes, a departure sight triangle to the right for. left turns should be provided for that design vehicle taming left from the median roadway. Where the, ax:dian is not wide enough to store the design vehicle, a departure sight triangle should be.proyided for that design vehicle to turn left from the minor -mad approach. The median width should be considered in determining the number of lanes to be crossed. The median width should be converted to equivalent lanes. For example, a 7-2-m 124 -ft] median should be considered as two additional lanes to be crossed in applying the multilane highway adjustment for time gaps in Exhibit 9-54. Furthermore, a departure sight triangle for left turns from the mtr dian roadway should be provided for the largest design vehicle that can be stared on r1 Metric US custalna fntersectiorn sight Intersedlon sight Stopping distance for . Stopping distance for Design sight ssen er cars Design sight p2astNer cars speed distance Calculated Design speed distance Calculated Design krnlh to m m Meh) ft ft ft 20 20 41.7 45 15 80 185.4 170 30 35 62.6 65 20 115 2211.5 225 40 50 85,4 8s 25 155 275.6 50 65 104.3 105 30 200 330.6 335 84 85 12511 130 35 250 385.9 390 70 105 146.0 150 40 305 441.0 445 80 130 166.8 170 45 360 496.1 5D0 90 160 187.7 190 50 425 551.3 555 100 185 208.5 210 55 495 606.4 610 110 220 229.4 230 60 570 661.5 665 120 250 250.2 255 65 M 716.6 720 130 28,5 271.1 275 70 730 771.8 775 75 820 826.9 830 80 910 882.0 885 Note. Intersection sight distance shown is for a stopped passenger car to tram left onto a two-lane highway with no median and grades 3 percent or less. For other conditions, the time gap rntW be adjusted and required sight distance recalculated. Exhibit 9-55. Design Intersection Sight Dist nce-_4 me BI—Left Tura From Stop Sight distance design for left turns. at divided -highway intersections ghould consider multiple design vdhicles and median width. If the design vehicle used to determine sight distance for a divided -highway intersection is larger than a passenger car, then sight distance for left turns will need to be checked for that selected design vehicle and for smaller design vehicles as well. If the divided -highway median is wide enough to stare the design vehicle with a clew%nce to the through lanes of approximately I m (3 ft] at both ends of the vehicle, no separate analysis for the departure sight triangle for Ieft turns is needed on the minor -road approach'for the near roadway to the left. In most cases, the depart= -sight triangle for right turns (Case 132) will provide sufficient sight distance for a passenger car to cross the .near roadway to reach the median. Possible exceptions are addressed in the discussion of Case B3. If the design vehicle can be std in the median with adequate clearance to the through lanes, a departure sight triangle to the right for. left turns should be provided for that design vehicle taming left from the median roadway. Where the, ax:dian is not wide enough to store the design vehicle, a departure sight triangle should be.proyided for that design vehicle to turn left from the minor -mad approach. The median width should be considered in determining the number of lanes to be crossed. The median width should be converted to equivalent lanes. For example, a 7-2-m 124 -ft] median should be considered as two additional lanes to be crossed in applying the multilane highway adjustment for time gaps in Exhibit 9-54. Furthermore, a departure sight triangle for left turns from the mtr dian roadway should be provided for the largest design vehicle that can be stared on r1 AASHTO--Gcvmctric Desig .ighways and Streets v c th h 0 IOU) d t3 8 g m wsua o o o cvt irri c rth ay m L E t o v r cv co a av v *v tow cq ea ECIDa?gaerepcnttCeh+[fnc aiC mCx -0 o cv0wca.-i ivmvvt c a.- N cv c*a v to as cq cn M r- O U rU'>M ' 00 'gr C3 cm– lii L7tD 7f gs i lvt4caC{Q( Cd? j fi v C11NLitRcpq yt' O 0Ctoa0Q nInoIrlQltiQ p a cc fn coWN Nc 1TiO © j Y cd tOrC*1 F s7opvoC Nu70?t- r- r- N N 04 F tp m etT`t*tvvmtiapcVepiC, W CO .- to m ai v Cd tri CiV) e< +- .- cv v un P- 0) M tD rn W03770r -r V RF sic ° u o m cc <0r- t (D n Lo Lo Nk"t o +- t jCT4- v3v4 cdc0-N. 0) QTS ala t va)N u? [O t ts] O cvmJE 112 WILSON PARK DIVISION 2 PLAT SUPPLEMENTAL TRAFFIC IMPACT ANALYSIS CITY OF RENTON Prepared for Mr. Robert Wilson 21703 60t" St. E. Lake Tapps, WA 98391 Prepared by r0qffEX 7-14.4 FFl c EXPERT -s 11410 NE 124" St., #590 Kirkland, Washington 98034 Telephone: 425.522.4118 Fax: 425.522.4311 January 25, 2012 city Of r-'ento-, DVi5,C11 h,. 2 qp+wV7 Fay Com - EXHIBIT 12 6 rraff,my January25, 2012 Mr. Robert Wilson 21703 60th St. E. Lake Tapps, WA 98391 Re: Wilson Park Division 2 Plat - City of Renton Supplemental Traffic Impact Analysis Dear Mr. Wilson: NCRTHWEST TRAFF/C eXPERTS 11410 NE 124th St. #590 KWr 1, 0 98034 Phone. 425.522,4118 Fax: 425,522.4311 We are pleased to present this supplemental traffic impact analysis (TIA) for the proposed 10 lot Wilson Park Division 2 Plat located on the north side of S.55 1h St. in the City of Renton. This TIA supplements the information and analysis presented in the original Wilson Park Plat TIA, dated June 23, 2009, prepared by Traffex. The Wilson Park Division 2 site is adjacent to the southwest corner of the approved Wilson Park Plat. The proposed project site contains the access road to S. 55 h St. for Wilson Park Plat. The 10 lots of the proposed Wilson Park Division 2 will have direct driveway connections to the access road connecting the Wilson Park to S. 55th Street. The access road and the location of its intersection to S. 55th St remains the same as when approved for the original Wilson Park Plat. The scope of this analysis is based upon the preliminary plat site plan, the Cityof Renton Policy_ Guidelines for Traffic Impact Analysis for New _Development. Our summary, conclusions and recommendations begin on page 5 of this report. PROJECT DESCRIPTION Figure 1 shows the Wilson Park Division 2 site plan. The site lies between the southwest corner of the Wilson Park plat and S. 55th Street. The proposed project utilizes the same access to S. 55th St. as the approved 12 lot Wilson Park plat. The site access street intersects S. 55th St. on the outside of a horizontal curve on S. 55th St. to optimize sight distance in both east and west directions for vehicles entering and exiting the site. Page 1 Wilson Park Trafff wC Development of the Wilson Park Division 2 plat is expected to occur by the year 2014. Therefore, for purposes of this study, 2014 is used as the horizon year for this study. TRIP GENERATION AND DISTRIBUTION The 10 single-family units in the proposed Wilson Park Division 2 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 Trips Total Trips per unit Entering Exiting 48 Average Weekday 9.57 96 500 % 50% AM Peak Hour 0.75 2% 68 75% PM Peak Hour 1.01 410 63% 37% 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 Eighth 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. Figure 2 shows the site generated traffic volumes and distribution at the study intersection. The distribution is based on existing traffic volume patterns, the characteristics of the road network, the location of likely trip origins and destinations employment, shopping, social and recreational opportunities), expected travel times, and previous traffic studies. EXISTING PHYSICAL CONDITIONS The streets in the study area are classified per the City of Renton Comprehensive Plan as follows: Talbot Rd. S S55 1h St. Page 2 Collector Arterial Local Access Wilson Park rraffmy 98th Ave S Local access 98th PI. S Local access 102nd Ave S Local access S 551h St. consists of two 11 ft. lanes and a shoulder that varies in width from approximately two to four feet in the vicinity of the project site. A section of S 55th St, east of the project site consists of several sharp curves and is posted with a 15 mph advisory speed sign and with chevron arrows at each curve within the section. There is a left tum pocket on S 55th St. at 981h Ave. S, approximately 125 ft. west of the Wilson Park site access street. EXISTING TRAFFIC CONDITIONS Traffic Volumes Figure 2 shows existing, future without project and future with project PM peak hour traffic volumes at the proposed site access street/S 55th St. intersection. The proposal generates less than 30 PM peak hour trips and no other intersection or street segment in the City of Renton will experience an increase of 5% in traffic volumes due to this development. Therefore, only the site access street/S 55th St. intersection requires a level of service (LOS) analysis per the City of Renton Policy Guidelines for Traffic Impact Analysis for New Development, A PM peak hour traffic count taken for the Wilson Park Plat TIA was used for this supplemental analysis since traffic growth in the area has been generally flat over the past several years. Level of Service Analysis Level of Service (LOS) is a qualitative measure describing operational conditions within a traffic flow, and the perception of these conditions by drivers or passengers. These conditions include factors such as speed, delay, travel time, freedom to maneuver, traffic interruptions, comfort, convenience, and safety. Levels of service are given letter designations, from A to F, with LOS A representing the best operating conditions (free flow, little delay) and LOS F the worst (congestion, long delays). Generally, LOS A and B are high, LOS C and D are moderate and LOS E and F are low. Table 1 shows calculated level of service (LOS) for future conditions including project traffic at the pertinent street intersection. The LOS was calculated using the procedures in the Transportation Research Board Highway Capacity Manual 2000. The LOS shown indicates overall intersection operation. At intersections, LOS is determined by the calculated average control delay per vehicle at signalized intersections or the average delay for the worst minor approach at two way stop sign controlled intersections. The LOS and corresponding average control delay in seconds are as follows: Page 3 Wilson Park rraffay TYPE OF INTERSECTION A B C D E F Signalized 10 10.0 and 20.0 and 35.0 and 55.0 and 80. 20.0 35.0 55.0 80.0 0 Stop Sign Control 1 10 and X15 15 and X25 25 and <35 35 and X50 50 FUTURE TRAFFIC CONDITIONS WITHOUT THE PROJECT Figure 2 shows projected 2014 PM peak hour traffic volumes without the project. These volumes include the existing traffic volume counts, plus background traffic growth, plus 12 PM peak hour pipeline project trips generated by the Wilson Park plat. The background growth factor accounts for traffic volumes generated from other approved but unbuilt subdivisions and general growth in traffic traveling through the area. A 3% per year annual background growth rate was added for each year of the five year time period from the 2009 traffic count to the 2014 horizon year (for a total of 15%). This will result in a very conservative analysis since traffic volumes in the area have been generally flat for the past several years and are anticipated to continue this trend. FUTURE TRAFFIC CONDITIONS WITH PROJECT Figure 2 shows the projected future 2014 PM peak hour traffic volumes with the proposed project. The site -generated PM peak hour traffic volumes were added to the projected future without project volumes to obtain the future with project volumes. Table 1 shows calculated LOS for future with project volumes at the Wilson Park Division 2 site access street/S. 55th St. intersection. The study intersection operates at a high LOS B for future 2014 conditions, including project -generated traffic, and meets the City of Renton LOS requirements for intersections. SIGHT DISTANCE EVALUATION Sight distance on S 55th St. at the proposed site access street was extensively evaluated in the Wilson Park TIA and meets the City of Renton intersection and stopping sight distance requirements in both the east and west directions. Page 4 Wilson Park Traffmy TRAFFIC MITIGATION REQUIREMENTS The City of Renton requires a Transportation Mitigation Fee payment of $75 per new daily trip attributed to new development. The net new daily trips due to this development are 96 trips (10units x 9.57 daily trips per unit). The estimated Transportation Mitigation Impact Fee is $7,200 (96 daily trips X $75 per daily trip). SUMMARY, CONCLUSIONS AND RECOMMENDATIONS We recommend that the Wilson Park Division 2 Plat be constructed as shown on the site plan with the following traffic impact mitigation measures: Construct the street improvements including curb, gutter and sidewalk for site access street as shown on the site plan. Contribute the approximately $7,200 Transportation Mitigation fee to the City of Renton. No other traffic mitigation should be necessary. If you have any questions, please call 425-5224118. You may also contact us via e-mail at vince(L-tnwtraffex.com or larry@nwtraffex.com. Very truly yours, Vincent J. Geglia Principal TraffEx Page 5 as: "02 Larry D. Hobbs, P.E. Principal TraffEx TABLE 1 PM PEAK HOUR LEVEL OF SERVICE SUMMARY WILSON PARK PLAT TRAFFIC IMPACT ANALYSIS INTERSECTION EXISTING 2014WITHOUTI PROJECT 2011 WITHIPROJECT Site Access SVS 55th St. I - NA- B 10.4 SB B 10.5 SB XX Number shown is the average control delay in seconds per vehicle for the minor approach for unsignalized intersections, which determines the LOS for intersections per the Transportation Research Board Highway Capacity Manual 2000 B Indicates calculated level of service SB (Southbound) Indicates direction of the minor approach for unsignalized intersections Page 6 w LE 5,905+/-S0. ff, 5,5604/ -Sy FT, s ' IN LOT 2 tG`. I 5,905+f -S}. R. LOT LITT 1 » 5,77ZE.s I243i 5 5 MOA, LOT 10 n 6,779+f-50. SSiH AVE. SOUTH ror.w Wilson Park Division 2 Plat - City of Renton Site Plan Figure 1 i 1 rlM ES AN-.wv .71707'_ _--"- I - 1 L -PO ' l a-zz x RACY A y 5,9094/-99,i1. i 7 fol.ft' rY LOT 6 5585+/ -SA FS. \ 1 4 taxsr bio i w LE 5,905+/-S0. ff, 5,5604/ -Sy FT, s ' IN LOT 2 tG`. I 5,905+f -S}. R. LOT LITT 1 » 5,77ZE.s I243i 5 5 MOA, LOT 10 n 6,779+f-50. SSiH AVE. SOUTH ror.w Wilson Park Division 2 Plat - City of Renton Site Plan Figure 1 NL7R7-H1YE5'T TRA rric Ex,-,rp ns i SE MTO ST F SE MN ST ss a r MM it i NTH ST M j sO.Ow sr t Future Project Future Without Generated With Existing Project Trips Project 0-,J k 0 468-121 6 JJ - 2 140 5 J ` 1 0'0`0 11-1 ` 3 544-0-340540 Wilson Park Division 2 Plat - City of Renton Figure PM Peak Hour Volumes for Existing and Future Conditions 2 TECHNICAL APPENDIX TWO-WAY STOP CONTROL SUMMARY General Information Site Information nal s1 enc /Co. Date Performed 6/19/2009 Analysis Time Period IPMpeak East/West Street: S 55th St 7 5 intersection Orientation: East-West Volume Vehicle Volumes and Adjustments Major Street 0.93 Eastbound Movement 1 2 Percent Grade (%) L T olume 6 540 eak-Hour Factor, PHF 0.93 0.93 Hourly Flow Rate, HFR 6 580 Percent HeavyVehicles 0 Median Type RT Channelized Lanes 0 1 onfi uration LT stream Signal 0 Minor Street Northbound Movement 7 5 L Volume 0 Peak -Hour Factor, PHF 0.93 Hourly Flow Rate, HFR 0 Percent Heavy Vehicles 0 Percent Grade (%) RT Channelized Lanes Configuration Dela. Queue L ration km) tvpn) c 5% queue leng Control Delay LOS Approach Delay Approach LOS 1-- and Level of EB 1 LT 6 1441 0.00 0.01 7.5 A WB 4 Intersection 5 Jurisdiction T Renton Analysis Year 2 2014 Future Without Project 0.93 150 2 North/_South Street: Site Access St 5tudv Period (hrs): 0.25 Illllllllii Northbound 7 8 9 Istbound 5 6 T R 140 2 0.93 0.93 150 Northbound 7 8 9 Istbound 5 6 T R 140 2 0.93 0.93 150 2 0 a HCS2000 Copyright C, 2000 University of Florida, All Rights Reserved Version 4.1 c r 0 Southbound 0 0 0 0 II II HCS2000 Copyright C, 2000 University of Florida, All Rights Reserved Version 4.1 c TWO-WAY STOP CONTROL SUMMARY General Information Site Information Co. Performed Analysis Time Period Project Description 6/1912009 PM peak Intersection urisdiction Analysis Year Renton 2014 Future with Project East/West Street: S 55th St North/South Street: Site Access St Intersection Orientation: Fast -West IStudy Period hrs : 0.25 Vehicle Volumes and Adjustments Major Street Eastbound Westbound Movement 1 2 3 4 5 6 L T R L T R Volume 11 540 0 0 140 3 Peak -Hour Factor, PHF 0.93 0.93 0.93 0.93 0.930.93 Hour! Flow Rate, HFR 11 580 0 0 150 3 Percent Heavy Vehicles 0 0 Median Type Undivided RT Channelized 0 0 Lanes 0 1 0 0 0 Configuration LT TR Upstream Signal 0 0 Minor Street Northbound Southbound Movement 7 8 9 10 11 12 L T R L T R Volume 0 0 0 2 0 6 Peak -Hour Factor, PHF 0.93 0.93 0.93 0.93 0.93 0.93 Hourly Flow Rate, HFR 00 0 1 0 2 i 0 6 Percent Heavy Vehicles 0 0 0 0 0 0 Percent Grade (°1°) 0 0 Flared Approach N N Storage 0 0 RT Channelized 0 0 Lanes 0 0 0 0 0 0 nfiguration LR Queue Len th, and Level of ServiceDpenay, proach EB WB Northbound Southbound vement 1 4 7 8 9 10 11 12 Lane Configuration LT LR vph) 11 8 C (m) (vph) 1440 668 Ic 0.01 0.01 5% queue length 0.02 Q.04 ontrol Delay 7.5 10,5 LOS A g 4 Approach Delay 10.5 pproach LOS g HCS2000T M Copyright C 2000 University of Florida, All Rights Reserved Version 4.l c Nb -id S311nun/aEWN"Cl Slim 183902i td Yd'fIDOLYa iLWIN°] p 3y 7a,v, avu,wmw,oc,aea o g r a9aMDN$ 33.p Z# 2 tld IVOS1IM a d W r U M V) d J o e j Z EXHIBIT 13 adar uw ra xasN,u .o„ N01WHSHM 'No1N 38 e ovo/m aN xaed NOMIM pw a=Q 000 Nb -id S311nun/aEWN"Cl Slim 183902i td Yd'fIDOLYa iLWIN°] p 3y 7a,v, avu,wmw,oc,aea o g r a9aMDN$ 33.p Z# 2 tld IVOS1IM a d W r U M V) d J o e j Z EXHIBIT 13 adar uw ra xasN,u .o„ N01WHSHM 'No1N 38 e ovo/m aN xaed NOMIM April 15, 2012 CITY OF REN T ON RECEIVED APR 16 2012 Jennifer Henning, Current Planning Manager BUILDING DIVISION CED — Planning Division 1055 South Grady Way Renton, WA 98057 RE: LUA12-013, ECF, PP, PPUD (Wilson Park 2 Preliminary Plat) Ms. Henning: Thank you for the opportunity to provide comments on the above application. As the owners of property adjacent to the subject site (located directly northwest of the site), we have an interest in insuring negative impacts are avoided and appropriate measures are taken in the possible development of this site. We also commented on Wilson Plat 1. In as much as the development of this site is directly related to and is proposed to be done concurrently with Wilson Park 1(approved by the City in 2010), some of these comments will be related to this development in its entirety. Comments/Concerns: 1. DRAINAGE Development of proposed Wilson Park 2, as well as Wilson Park 1, will certainly change the current site drainage due to increased impervious surfaces. significant changes to the existing slopes and changes in the current vegetation/tree coverage will mean a change in the current natural drainage of the sites. The Wilson 2 Plat proposal indicates it would be using the detention vault proposed for the Wilson 1 Plat. We are concerned that the vault be engineered to accept this significantly increased additional use. We are further concerned that the outflow be properly managed. Should the open drainage ditches along S. 55th Street be used for this increased outflow due to development, measures should be in place to insure these ditches to not overflow. Under new City practices, it is assumed that the City will be the owner of the detention vault and responsible for its maintenance and repair. Due to the unusual location (beneath a public street), design/engineering should insure that the vault can accept the gross vehicle weights of large trucks (garbage trucks, large fire engines, etc.). EXHIBIT 14 2. ROADS The roads serving the proposed plat are outlined in the Wilson Park 1 plat and indicate that parking will be allowed on one side of the street. As this is the case, we recommend the City identify ahead of time which side of the road vehicles will be allowed to park. Our neighborhood is also on a hill and based on our HOA experiences, we suggest for Wilson Plat 2 that parking be on the east side of the road entering the plat and the south side of the road in the Wilson 1 plat. We suggest the sidewalks mirror parking and be "only" on the side of the road where parking is allowed. The suggestions for east/south side parking are: This may aid in minimizing a risk issue identified in the Plat 1 application, that being road conditions (the down slope of the east -west roadway) during winter weather. Parking "only" on the east/south side may give a Wilson Plat 1 homeowner more "road" to maneuver in "icy road conditions" especially at the bottom on the curve area. If people are parked there, there is no place to maneuver one's vehicle without hitting another vehicle. Prohibiting vehicles being parked on the west and north sides of the road at the curve area of the two new roads may avoid parked vehicles being struck by vehicles sliding downhill during poor weather road conditions. Keeping people parking on the east and south side of the roadway may also minimize vehicles parking illegally on City streets by parking in the "wrong direction" (RCW 46.61.575). This RCW mentions vehicles parking with tires against the "right side of the curb". Parking on the east and south sides encourages this as drivers tend to enter and park to the right curb as opposed to turning their vehicles around (facing downhill) prior to parking on the opposite side of the street. The proposed road entering from S. 55th Street is indicated as being 26 feet wide with parking allowed on one side of the road. RMC 4-6-060 (2009) requires that 6' parking lanes be allowed for on one side of a residential street. This same RMC requires an 8' parking lane on arterial streets. It is confusing that the RMC seems to indicate that vehicles parked on residential streets needs less width to park than vehicles parked on arterial streets. On paper, for calculation purposes, the required 6' parking lane subtracted from the 26' road width leaves 20' for vehicles access (particularly emergency vehicles). In reality, the parking width needed for a legally parked vehicle is 8', subtracted from 26', leaves an 18' width for emergency vehicles (below recognized nation standards). While the submitted roads within the plat meet the current RMC, the City made consider revisiting the long-term impacts of allowing substandard street widths on residential streets. Plat 2 indicates sidewalks on both sides of the street and Plat 1 indicates sidewalks only on one side of the street. We suggest that if sidewalks are only required on one side that they be placed only on the 'parking only' of the street. Moving the sidewalk to the south side of the street in Plat 1 would allow a connected flow between the plats and tie them together with the walking path in Plat 2. Elimination of the west side sidewalk in Plat 2 would allow for a wider roadway (creating better parking space on the east side of the street). There remain significant concerns over the protection of the four (4) Geneva Court subdivision properties located west of the new roads serving Plat 1 and 2. These new roads run directly ABOVE the adjacent homeowners lots. Headlights from vehicles driving in a westerly direction on the street in Plat 1 at night will be aimed directly at the rear of the houses in the adjoining Geneva Court neighborhood. We are also concerned if vehicles on the new road lose control at the bottom of their hill, they will breach our wooden 5 foot current fences and end up in our backyard. Lastly, we are concerned with noise and visual impacts that minimize our enjoyment of our properties. We feel the impact could be minimized by installation of a safe, sturdy, tali retaining/barrier wall across the back of all 4 current homes (along the entire western section of Plat 1). Currently there is only a 5 foot wooden fence on a slope. We suggest a retaining wall which is at least 6 foot tall and concrete. The concrete wall would be to the east of our current wooden fence. To the east of the new concrete barrier wall, we ask that Evergreen trees (such as fast growing Leland Cypress trees) be planted as they will also help with noise and visual impacts. 3. ACCESS The issue of access to the Wilson Plats from and to S. 55th Street was identified and addressed in the Plat 1 process. Concern remains that this access point will become problematic, due to the serpentine nature of the road, the narrow width of the existing S. 55th Street and the significant slope of the roadway on S. 55th. Concerns exist over how school buses will safely (for students and other drivers) serve these new homes as weft as delivery trucks, garbage trucks, etc. While sidewalks are being required for the new plats, there are currently NO sidewalks on S. 55th Street. So the Wilson Plat sidewalks do not lead to "anywhere". Due to the narrow existing shoulder and narrow road width, pedestrian foot traffic on S. 55th (outside of and serving the Wilson Plat) is either not possible or done at a risk that is beyond acceptable — especially to children. During the Wilson Plat 1 process, the establishment of a homeowners association HOA) was identified as a requirement. It is recommended that with Wilson 1 and 2 being developed concurrently that only one homeowners association be established serving both Wilson 1 and 2 (as opposed to two separate associations). During the Wilson Plat 1 process, concerns from adjacent homeowners as well as from the Hearing Examiner were made about impacts (visual and safety issues) along the adjoining boundary with the existing Geneva Court subdivision (located to the west of the site). These concerns remain and it is requested that part of the concurrent Wilson 1 & 2 development address these (safety & visual). A safe and adequate separating retaining wall (prefer a minimal height of 6 feet and concrete) along the entire western section of Plat 1 is requested. Currently there is only a 5 foot wooden fence on a slope. The maintenance of this retaining wail shall be the responsibility of the Wilson HDA. Candidly, it has been difficult to determine what has been approved for the final Wilson Plat 1. Our understanding is that no final plat site map exists indicating final outcomes of the Hearing Examiner (4/1/10), the appealed changes, or the Council's actions (8/16/10). Absent drawings that reflect the written changes, if it difficult to make informed comments on development impacts. Respectfully submitted, Paul & Frieda Witt 617 S. 53" Place Renton, WA 98055 425) 227-5462 Jonathan Vu 622S53 rd Place Renton, WA 98055 808) 218-4403 Khanh Nguyen 616553 rd Place Renton, WA 98055 425) 271-3691 Quang Dang and Kim Duong 623 5 53rd Place Renton, WA 98055 425) 917-9733 yPr"i j W F y 4 •fid i9.`7 .Eii'i z. VIE ryt e ". art iR• i7r '/ yy lk y kt G Aptk { t z e; IM o u A N o 0 o O N s m m U N Q O C N tU6 m z l Z N y N N C L N N d NQ n n n n 67U C O Q7 t 41 lC U1 P] C] Y Y i Z Vl Vl F C7 m OpD, C O d O L a5 i O CV V' C7 T y EXHIBIT 16 1 kt Aptk { t e; IM o EXHIBIT 16 1 4 W Cp SA OHO P , LeoD[,aN01u 1Jk 9 iGd6 N1L'MIDS'M'Fi6111 81 Ndld 9NIQV89 SLIM 12i3902i Z#>I'dVd NOS]IM > Jxoaa a w FF L gg m i aw J! J J{ F d Q a zof 09 w aoav rswl m x lo .al L,J f} W N Ndld 9NIQV89 SLIM 12i3902i Z#>I'dVd NOS]IM > Jxoaa 11] a w FF i aw J! J FBF J{ F d a a w t W n o N t 11] w FF i J! J FBF J{ F d w ILr1LL .. F; 1 Z LUto LU!`_'/ O Z Y Er0 EL r wo •..,., ane/nyv:e/awwa „ lura NOiCNIHEYM 'NOIN. d No lmam 3QZ# HdYd NOSIIM T~ f F J ,81 F FF J 30 0 EXHIBIT 17 FF i J! J FBF J{ F wo •..,., ane/nyv:e/awwa „ lura NOiCNIHEYM 'NOIN. d No lmam 3QZ# HdYd NOSIIM T~ f F J ,81 F FF J 30 0 EXHIBIT 17 LIU & ASSOCIATES, INC. Geotechnpca? Engineering -- Eng,r eering Geobgy February 15, 2012 Mr. Robert Wilson 72() South 551h Street Lake 'l'apps. WA 98391 Dcar Mr. Wilson: Subject: Addendum No. 1 to 111'22!2004 0cotechnical Report Creotechnical Enginecrins; Study Proposed Residential Development South 55th Street and Morris Avenue South Renton, Washington L&A Job No. 41134 INTRODUCTION Earth sconce t. fig-i(11,;` f1c; 7r1 We previously completed a geotechnical engineering study for the site of a proposed 4 -lot short plat. located at the above address in Renton. AXashington. with our findings. conclusions and recommendations presented in our 1112212004 report titled Geotechnical Engineering Studv. Proposed 4 -Lot Short Plat, 98xx South 192" Street., Renton. Washington.- We understand that expansion of the subject project to include more land to the east of the original site is being contemplated. This added land generally rises moderately to the cast. The purpose of this addendum is to explore subsurface condition of this added land and evaluatc its stability to assure the geotechnical recommendations for grading_ surlace and ground water control. erosion abatement. site stabilization. and foundation design and construction presented in our 11,221,21004 geotechnical report are also applicable to the development of the added land. Presented in this addendum are our findings and conclusions. 19213 Kenlake Place NE - Kenmore, Washington QRn,2p Phone (425) 483-9134 - Fax (425) 486-2746 EXHIBIT 18 Pref o 2 5. Fcbruary I5. 201 Addendum No. i - Proposed Residential Development L&A Job No. 4A1 4 Page PROJECT DESCRIPTION The project site is to be accessed from its south side by a roadway off South 55" Street going northward into the site. The original land will be lying on the west side of this read and the added land lying east of the road. The original land is generally flat. while the added ]and slopes upward easterly moderately. The added land is flanked b}Y a steep slope up to about 6 to 1' feet high on its west side which appears to be a tut slope made years ago to allow the origin land being graded flat. The added land is dotting by tall mature. deciduous and evergreen trees and covered by dense brush and vine. The trees are all straight voth no bents in the trunks or do,.N•nbill leaning. No signs of' erosion or sail movement have been noted within the added land. SURFACE CONIIITTONS Subsurface condition of the: added land was explored with three test pits excavated on FebruaiN''F. 3011. to depths front 6.01 to 6.5 feet. The approximate locations of the test pits are shoN n on Plate I - Site and Exploration Location Plan. The test pits -, -ere located with either a tape measure or by visual reference to existing topographic features in the field and on the topo Taphic surrey- map. and their locations should be considered oniv accurate to the measuring method used. A geotechnical engineer from our office was present during subsurface exploration, who examined the soil and geologic conditions encountered and completed logs of test pits. Soil samples obtained from each soil unit in the test pits were visually classified in general accordance -with l?nited Soil Classification Stistem. a copy of which is presented LIU & ASSOCIATES, INC. Fehruan 15. 2112 Addendum No. l - Proposed Residential Development LSA Job No. 4A 131 PaL,e 3 on Plate 2. Detailed deicriptions of soil units encountered during site exploration are presented in the test pit Ings on Plates 3 through 4. The test pits encountered a layer of loose, organic topsoil, k`rom 8 to 10 inches thick-. on the surface. The topsoil is underlain by a laver of brntiN-n tel light-bro-wri.. ablation rill weathered till) of medium -dense. silty fine sand, with a trace of to some gravel and occasional cobble and boulder. about 3-5 to 4.2 feet thick. Underling the ablation till to the depths explored is a iodgmont till (fresh till) deposit of light -brown to light -gray. ver\ -dense, -% eakly-cement, silty line sand with same gravel. The soil condition of added land is generally similar tea that of the original land. GROUNDWATER CONDITION Grounds+ater seepage was not encountered in any of the test pigs excavated on the added land. DISCUSSION AND CONCLUSION Bascd on the subsurface (sail and ground«atcr) condition encountered in the test pits excavated on the added land_ the geotechnical recommendations in our 11,22 1-004 geotechnical report should also be applicable to the development of the added land. it is our opinion that added land should be quite stable and geologic hazards Over the added land should be minimal if the recommendations ui our 11/221`2004 report are full implemented and observed during. construction. L1U & ASSOCIATES, INC. l= ebruan. 15. 201 Addendum No. 1 - Proposed Residential Development L&A Job No. 4A 134 Pavc 4 DRAINAGE IMPROVEMENT A drainage course of surface «eater cc as obscn-ed corning den+'n the hillside on the eastem half ref the south side of the site, then flo tiing through a culvert into a ditch along the north side of South 54`'' Street. The " ater in this drainage course appears to be storm%rAter released #Tom the development east of the project site and dumped onto the subject site. It is our opinion that this storn c ater should be collected and re routed in a pipe off the project site. CLOSURE We are pleased to be of service to you on this project. Pleasc feel free to contact us if you have any que itions regarding this report or need further consultation. Four plates attached G S. Yours -very truiv. LMi &,70CIATES INC. he4 J. S. (Julian'.) Liu, Ph.D., Y.T. Consulting Geotechnical Engineer LIU & ASSOCIATES, INC. Wilsons 253-862-7285 p.2 Fc OF - r fit 18 . 2 Aln r j LI 1 t}n y+ U I` 3 d ROAD A J2 L},1L rii iI I lzv x F[ i 5_•.75- wr.. Ai L q 7r7S7 1 s 1 l t FF rte 11 c 15 B5"5L h L LFL X : sz Fc OF - r fit 18 . 2 Aln r j LI 1 t}n y+ U I` 3 d ROAD A 1 . L},1L rii iI I lzv I 8,'ri 5_•.75- O 1 _ t P— 3; i aID a y+ c c_... L 8,'ri 5_•.75- t FF rte 11 c 15 B5"5L h L LFL X : sz Ffiw i r; 5 : Ac- r CuIESS l f 1 V' y t`•Ct f I 1 .'4c : SOCI TES, INC . I UiE•:^.'. _ :f-'f1'} - lQ,'I?tif'f _ w"I _4' E?C1 v-s9CE r S:`•_'wS.T+._C: ^ate f ... 7 SITE AND LOCATION PLAN RESIDENTIAL DEVELOP VIENT S. 55TH, STREET AND MORRIS AVENUE S- ? RENTON, WASHINGTON UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP GROUP NAME SYMBOL GRAVEL CLEAN GVV w.E -Dh6:c ,P"VEL F. Tc; s_ ,.. c G CitF E CORSE- M ;FC T NAt„ $D%• 0F GRAVEL GP RLQ- DE GRAVEL GRAVEL 11>,'ITH GM SILTY GRAVELGRAINED4OARSEFR6:.'710N SOILS FETAINED Qf: fi;D 4 SIEVE FINES GC CLAYEY GRAVEL SAND CLEAN SW IIVELL-GRADED SAND FirlE TC COARSE SA Z MZ)RE THAT, 5091 rV,vPE T 41-.' 5G, OF SAND SP PCORR,Y-GRADER SAN-E) SAND NINTH SM LT'Y SANDRETAINEDOPJTHECOARSE=RACTIQN SL aLt- S1EVE PASSING N: 4 &EVE FINES SC CLAYEY SAND FINE- SILT AND CLAY INORGANIC PJ'L 5"-T CL eL YGRAINEDLIQUIDU% T ORGANIC CL ORG6-NIC SSLT- ORGAN , CLAYSOILSLESSTHAN504.k QOR= THAN SC`r. LTY AND CLAY i INORGANIC Mei SILT OF i;fGlt PLA STICiT'x EJiSTIC SS; E CLAY OF H,'GH PLASTICITY FAT CLAYPASSINGON, THECH LfOti'3 L}nq' ORGANIC OH ORGANIC SILT. ORGAWh SILTNOn'? SIEVE rzl* OR MORE HIGHLY ORGANIC SOILS P7 PEAT Anc nTHFR HIGHLY dGAf.' C s:LS NOTES: SOIL MOISTURE MODII=IERS: i FlcLLi CLASS'F!CATI A's i5 BASED ON DRY -ABS-ENKE d MOISTURE DUSTY DRY -10 OF SO!L IN GENERAL ACCORDANCE WITH AST%l D2'A:a-E s THE TOUCH SOIL CLASSIFICATr?, ;;SING LA50Ra E ORY TESTS IS SASED SLIGHTLY V.O ST - TRA;vE VwA$TURE N'C* DUS7" 0N ASTf,, D74ii?z?3 MOiS'r _ DAMP. B'JT f 'V§S fBLE WATER 3 D`SCRIP! PANS Or SOIL DENS.T` dR CONSISTPNOY f RE wERV MCIST - VERY DAr%?,F, MOISTURE Fc L7 TO 1—HE TJ'.rC- 8645'=D ON 'NTERPRE'A T ION OF BLOtN-DOJ."'.': DA.Tk. V.SUAL WET - VISIBi-E FREE WATER OR SA`URATED APPEAP.A,tiC;E O SO:LS AND DR -EST CA-:A USUALLY SOIL IS CETA,'NED FRDM SELO'v V^ ATER TABLE LLL, & ASSOCIATES, INC. UNIFIED SOIL CLASSIFICATION SYSTEM Gent¢--hhvCni Fng-neerinO FhQlneeNrlC GtOtclg) Ea-,,) Svto F. PLATE 2 TEST PIT NO. 1 Logged By. JSL date 2!28,'2011 Ground E! t Uep:h f RSCS CLASS So;! Description Samp>c ND w Ker - fest OL Brush and duff on surface f Dark -brown, loose. omanic, silty fine SAND, r+th fine roots. SiJ• rr gist j(7TOPSOtLj 2 Brown to light -brown, medium --dense, silty fine SAND, time gravel, 3 occasional roots, moist (weathered VASHON TILL) 3 4 5 S1 Light -gray. very -dense, silty fine SAND, some gravel, weakly - SM Light -gray, very -dense, silty fine SAND, some gravel. weakly - 5 moist (fresh VASHON TILL) 7 Test pit terminated at 6.0 ft; groundwater not encountered E Test pit terminated at 6.5 ft; groundwater rhot encountered. 8 c 16 11 Logged By: JSL TEST PIT NO. Date: 212 8120 1 1 2 Ground EI. t Depth i. USCS CLASS_ Sc.+ Description Sample N0. w Cher Tey: OL Vint: and duff on surface t Dark -brown, loose, organic. silty fine SAND, with fine roots. SPJI molstLTOPSOIL)-__________ ________J' 2 Light -broken, medium -dense, silty fine SAND, trace to some gravel, 3 occasional cobble and boulder, moist (weathered VASHON TILL) 4 5 S1 Light -gray. very -dense, silty fine SAND, some gravel, weakly - 6 cemented, moist fresh VASHON TILL' 7 Test pit terminated at 6.0 ft; groundwater not encountered E 10 LIU & ASSOCIATES, INC. Geotechnical Engineering Engineering Geology Earth Science TEST PIT LOGS RESIDENTIAL DEVELOPMENT S. 55TH STREET & MORRIS AVENUE S. RENTON, WASHINGTON JOB NO. 4A134 I DATE 3/612011 1 PLATE 3 Logged By. JSL TEST PIT NO. Date, 2t28r2011 11 Ground EI. ± DepiF ft USCS CLASS Soil Description Sample No. W Other Test OL Brush and duff on surface 1 Dark -brown loose. organic- silty fine SAND, with roots. , SAS moistOEgOTl_ _ _ _ _ _ _ _ _ _ _ ' 2 Ught-brown to yellowish -brown, medwrn-dense: silty fine SAID trace gravel and occasional cobble and boulder, moist 3 weathered VASHON TILL) 4 Sf 4 RLight-gray, very -dense. silty fine SAND, same gravel -weakly g moist fresh VASHON TILL 7 Test pit terminated at S 5 ft. groundwater not encountered. 8 9 11 TEST PIT NO. Logged By- JSL Date: Ground El, ± LTTT & ASSOCIATES, INC. Geotechnical Eng,nae-inc Engineenmo GeoS.-gy Ea-th Science TEST PIT LOGS RESIDENTIAL DEVELOPMENT S. 55TH STREET & MORRIS AVENUE S. RENTON, WASHINGTON JOB NO 4A134 IDATr= 316/2011 1 PLATE 4 J GEOTECHNICAL ENGINEERING STUDY 4 -LOT SHORT PLAT 98XX SOUTH 192ND STREET RENTON, WASHINGTON L&A Job No. 4A134 Date: November 22, 2404 - Prepared for: Mr. Karl Singh c/o Cramer Northwest, Inc. , 945 North Central Avenue, Suite 104 { Kent, WA 98432 vk Prepared By_ Liu & Associates, Inc. 19213 Kenlake Place NE Kenmore, Washington 98028 LIU & ASSOCIATES, INC. Geateehnical Engineering Engineering Geology Earth Science November 22, 2064 Mr. Karl Singh c/o Ms. Aiearma Kondelis Cramer Northwest, Inc_ 945 North Centra] Avenue, Suite 104 Kent, WA 98032 Dear Mr. Singh: Subject: Geotechnical Engineering Study Proposed 4 -Lot Short Plat 98xx South 192nd Street Renton, Washington L&A Job No. 4AI34 INTRODUCTION We have completed a geotechnical engineering study for the site of a proposed 4 -lot short plat, located at the above address in Renton, Washington. The general location of the site is shown on Plate 1 -- Vicinity Map. We understand that the proposed development for the site is to plat its western portion into four single-family residential building lots, on each of which a single-family residence will be constructed. The purpose of this study is to characterize the subsurface conditions of the site and provide geotechnical recommendations for grading, surface and ground water control, erosion abatement, site stabili-Zation, and foundation design and construction for the proposed development:. Presented in this report are our findings of the site conditions and geotechnical recommendations for the proposed development. PROJECT DESCRIPTION For our use in this study, you provided us with a topographic survey plan of the site, prepared by Cramer Northwest, Inc. As shown on Plate 2 - Site Plan and Exploration Location Plan, the 99213 Kenlake P12ce NE - Kenmore, Washington 98028 Phone (425) 483-9134 - Fax (425) 486-2746 November 22, 2004 Proposed 4 -Lot Short Plat L&A 7ob No. 4A134 Page 2 subject site is an irregularly-shaped tract of land, partially fronted by the right-of-way of the winding South 1920d Street to the south. The site is currently undeveloped and heavily wooded. We understand that the proposed development for the site is to platted its gently to moderately sloped western 95 feet into four single-family residential building lots. Site grading may require cut and fill to some degree for the northern two lots. SCOPE OF SERVICES Our scope of services for this study comprises specifically the following: 1 Review the geologic and soil conditions at the site based on a published geologic map. 2. Explore the subsurface conditions of the site with backhoe test pits. 3_ Perform necessary geotechnical analyses and provide geotechnical recommendations for site grading, site stability enhancement, erosion abatement, surface and ground water control, and foundation design and construction, based on subsurface conditions eacountemed in the test pits and results of our geotechnical analyses. 4. Prepare a written report to present our findings, eoncIusions, and recornmendati ons. SITE CONDITIONS SURFACE CONDITIONS The subject site is partially bounded by South 192nd Street to the south, and is 4oined by single- family residences to north and west and by a wooded land to the east. The site is currently vacant and undeveloped. It is situated on a moderate to steep, westerly -declining hillside. The terrain within the site mostly .slopes moderately to steeply down to the west, except that the ground within the western 95 feet of the site, which is to be developed into four building lots, is mostly gently to moderately sloped down to the west at grades from less than 5 percent to 32 percent. EIU & ASSOCIATES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A 134 Page 3 The middle of the proposed 4 --lot plat area has been cleared previously, with a remnant concrete driveway off South 192 l Street to about the mid -depth of the proposed 4 -lot plat area. The unpaved area is now overgrown with brush and berry bushes. Matured deciduous trees scatter throughout the interior (northern two lots) and the perimeter of the southern two lots of the proposed 4 -lot plat area, with occasionai mature evergreen trees mixed in between. GEOLOGIC SETTING The Geologic. Map of the Renton Quadrangle, King County, Washin tgton, by D_ R. Multineaux, published by U. S. Geological Survey in 1965, was referenced for the geologic and soil conditions at the site_ According to this publication, the. surficial soil units at and in the vicinity of the subject site are mapped as Kame Terrace (Qit) underlain by Ground Moraine (Qe. The geology of the Puget Sound Lowland has been modified by the advance and retreat of several glaciers in the past and subsequent deposits and erosion. The latest glacier advanced to the Puget Sound Lowland is referred to as the Vashon Stade of the Fraser Glaciation, which has occurred during the later stages of the Pleistocene Epoch and retreated from the region some 14,500 years ago. The kame terrace deposits were laid down by ice -marginal streams flowing between higher ground on one side and an ice margin on the other side during the last glaciation. They consist mostly of silty sand and gravel to cobble. Locally, they also contain lenses and pods of till and beds of sand, silt and clay. The kame terrace deposits were, however, not encountered by the test pits_ Instead ground moraine deposits were found underlying the site. The ground moraine deposits are mostly thin ablation till over lodgmont till, deposited by Puget glacial lobe of the Vashon Stade of the Fraser Glaciation. The lodgmont till is generally a LIU & ASSOCIA'T'ES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A lob No. 4A 134 Page 4 compact mixture of unsorted clay, silt, sand, gravel and cobble, commonly referred to as -hard pan". The ablation till is similar to lodgmont till, but is much less compact and coherent. The thickness generally varies from 2 to 4 feet for ablation till, and 5 to 30 feel for lodgmont till_ The lodgmont till is practically impervious, except local lenses of sand and gravel. It has the strength of a low-grade concrete and can stand in a steep natural or cut slope for a long period. The lodgmoat till can provide excellent foundation support with little settlement expected. The overlying ablation till is generally in a looser state, and is more compressible and permeable. SOIL CONDITIONS Subsurface conditions of the subject site were explored on November 14, 2004, with six test pits. The test pits were excavated with a fire -mounted -backhoe. to depths from 5.0 to 8.0 feet. The approximate locations of the test pits are shown on Plate 2 -.Site and Exploration Location Pian. The test pits were located with either a tape measure - r or by visual reference to existing topographic features in the field and on the topographic survey map, and their locations should be considered only accurate to the measuring method used. A geotechnical engineer from our office was present during subsurface exploration, wha examined the soil and geologic conditions encountered and completed logs of test pits. soil samples obtained from each soil unit in the test pits were visually classified in general accordance with United Soil Classification System, a copy of which is presented on Plate 3. Detailed descriptions of soil units encountered during site exploration are presented in the fast pit logs on Plates 4 through b. The test pits revealed that the site is mantled by a layer of loose, organic topsoil, from. 1.0 to 2.5 feet thick. The topsoil is generally underlain by a layer of brown ablation till soils of loose to medium -dense, silty fine sand, with a trace of gravel and occasional cobble and boulder, about LIU & ASSOCIATES, INC. e P. b November 22, 2004 Proposed 4 -Lot Short Plat I.&A Job No. 4A 134 Page 5 1.0 to 3.2 feet thick. The ablation till was, however, not encountered by Test Pit 3 located jus above the toe of the steep hili at about the mid -length of the eastern boundary of the proposed 4. lot plat. Underlying the ablation till to the depths explored is a lodgmont till deposit of light - brown to light -gray, dense to very -dense, weakly -cement, silty fine sand with a trace of gravel, except in Test Pit 2 where the ablation till was found underlain by weakly -cemented, fine -to - medium -grain sandstone bedrock. Fragments of this sandstone bedrock was also found mixed in the lodgmont till deposit in Test Pit 3. CONDMONIROUNDWATER roundwater seepage was not encountered in any of the test pits. The lodgmont till deposit and to a lesser extent the sandstone bedrock underlying the site at shallow depth is practically impervious and would perch stormwater infiltrating into the more permeable surficial topsoil and ablation till soils. This near -surface perched groundwater may dry up completely in summer months and may accumulate and rise during the wet winter months. The depth to and the amount of perched groundwater may fluctuate seasonally, depending on precipitation, surface runoff ground vegetation cover, site utilization, and other factors. DISCUSSION AND RECOMMENDAT1lONS Cl103V- Based on the soil conditions encountered in our subsurface explorations, it is our opinion that the site is suitable for the proposed development from the geotechnical engineering viewpoint, provided that the recommendations in this report are fully implemented and observed during construction. The loose topsoil and unsuitable weak soils in the root zone should be completely stripped within the driveways, the building footprints and where the subgrade soils are to support structural or traffic load. The dense to very -dense lodgmont till at shallow depth are of high LIU & ASSOCIA'T'ES, INC. November 22, 2004 Proposed 4 -Lot Short Flat L&A Job No, 4A 134 Page 6 shear strength and can provide excellent foundation support to driveways and buildings with little settlement. Conventional footing foundations placed on or into the underlying dense to very -dense lodgmont till soils may be used for supporting the houses to be constructed on the platted lots. Structural fill, if required for site grading, should be constructed over the underlying dense to very -dense lodgmout till soils following the stripping of surf cial unsuitable soils. The on-site topsoil and ablation till soils contain a high percentage of fines, and is sensitive to moisture. It can also be saturated quickly and result in heavy runoff with potential soil erosion over the steeper portion of the site during extended periods of heavy rainstorms. One or multiple Imes of _c_ 1nUi dramm hould be installed along the upslope side of the construction areas, as required, to intercept and drain surface runoff and near -surface perched groundwater to minimize soil erosion and facilitate site grading during construction. Perrnanent fill to be placed over slopes steeper than 15 percent grade should be retained structurally. Structural fill, if required for site grading, should be placed on compacted and proof -rolled, unyielding, undisturbed, firm, native soils, following the stripping of the surfcial unsuitable soils. The exposed ground exceeding 15 percent grade should be benched with vertical steps not exceeding 5 feet tall prior to placing structural fill. Storm runoff over impervious surfaces, such as roofs and paved driveway, should be collected and discharged into a storm sewer. Concentrated stormwater should not be discharged onto the ground anywhere within the site. LIU & ASSOCIATES, INC. v-4oa u r 0C_ p. c November 22, 2004 Proposed 4 -lit Short Plat L&A .lob No. 4A 134 Page 7 GEOLOGIC HAZARDS Landslide Razards The subject site is underlain at shallow depth by dense to very -dense, weakly -cemented, lodgrnont till soils of high shear strength and to a lesser extent by weakly -cemented sandstone. It is, therefore, unlikely for deep-seated landslides to occur on the site. The surficial topsoil and ablation till soils are loose to medium -dense. There is a remote chance that shallow, skin -type inudflows may occur in these surficial weak soils on steep slopes if they are overly saturated. To mitigate such potential, the vegetation cover over the site beyond construction limits should be maintained, concentrated storinwater should not be discharged onto the ground within the site or its adjoining properties, and spoil soils and yardwaste should not be disposed of onto the slopes within the site. Erosions Hazard The surficial topsoil and ablation till soils over the steeper portion of the site can be easily eroded when stripped of vegetation cover on steep slopes, while the underlying weakly-cernented lodgmont till soils are of moderately high resistance against erosion. To abate the erosion potential in the surficial weak soils, the vegetation cover outside of construction limits should not be disturbed. Concentrated stormwater should not be discharged onto the ground within the site. Spoil soils and yardwaste should not be disposed of within the site. Storm rtmoff over impervious surfaces, such as roofs and pavement, should be captured with underground drain line systems tied to roof downspouts and by catch basins installed in pavement, and tightlined to discharge into a stornn sewer or a suitable stormwater disposal facility. Unpaved, disturbed ground within the site should be re -vegetated to provide erosion protection. Once the drainage control measures for the roadways and houses are in place after the completion of the proposed development, the amount of surface runoff and near -surface groundwater now will be reduced which would further mitigate soil erosion and entrance site stability. LIU & ASSOCIATES, INC, November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A.134 Page 8 Seismic Hazard The site is underlain at shallow depth by dense to very -dense lodgmont till soils of very high shear strength. These competent soils and the general lack of static groundwater table at shallow depth under the site should make it rather unlikely for such seismic hazard as liquefaction or sail i/ lateral spreading to occur on the site. The proposed houses, however, should be designed for seismic forces induced by strong earthquakes. Based on the soil conditions encountered by the test pits, the site should be classified as Seismic Use Group I in the design of the proposed warehouse in accordance with the 2003 International Building Code (IBC). SITE PREPARATION AND GENERAL;. GRADING Site preparation for the construction of the residences should include clearing and grubbing within construction limits. Loose topsoil and weak soils in the root zone should be completely stripped within the driveways, the building footprints of the proposed Douses and in areas subject to traffic and structural loads. The exposed soils should be compacted to a non -yielding state with a vibratory compactor and proof -rolled with a piece of heavy earthwork equipment operated on the site. The on-site soils contain a high percentage of `fines and are sensitive to moisture. A layer of clean quarry spalls should be placed over excavated areas and areas of frequent traffic, as required, to protect the subgrade soils from disturbance by construction traffic. Silt fences should be erected along the downslope boundaries of the site to prevent sediments being transported by storm runoff onto adjoining properties or the street. The bottom edge of the silt fence should be embedded in a trench and ballasted with crushed rock or gravel. MLT & ASSOCIATES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A134 Page 9 EXCAVATION AND FILL SLOPES Under no circurnstance should excavation slopes be steeper than the limits specified by local, state and federal safety regulations if workers have to perform construction work in excavated areas. Unsupported temporary cuts greater than 4 feet in height should be no steeper than 1H:IV' in the surficial topsoil and ablation till soils of loose to medium -dense silty fine sand, and may be vertical in the light -brown to light -gray lodgmont till soils of dense to very -dense, weakly cemented, silty fine sand with a trace of gravel, or in sandstone bedrock, provided that the overall depth of cut does, not exceed 10 feet. Permanent cut backs should be no steeper than 2H:1 V in the surficial topsoil and ablation till soils, no steeper than 1-1/2H:1 V in the underlying lodgmont till soils. and no steeper than 1H -1V in the sandstone bedrock if encountered. The soil units and the stability of cut slopes should be observed and verified by a geotechnical engineer during excavation. Permanent fill embankments required to support structural or traffic loads should be constructed with compacted structural fill placed over proof -rolled, undisturbed, firm native, lodgmont till soils after the unsuitable surficial soils are stripped. Permanent fill to be placed on slopes raeper than 15 percent grade should be retained structurally. Sloping ground exceeding IS percent grade over which fill is to be placed should be benched with vertical steps no more than 5 feet high after stripping of unsuitable surfieW soils_ The slope of permanent fill embankments should be no steeper than 2H:1 V. Upon completion, the sloping face of permanent fill embankments should be thoroughly compacted to a non -yielding state with a hoe pack. The above recommended cut and fill slopes are under the assumption that groundwater seepage will not be encountered during construction. if encountered, the construction work should be immediately halted and the slope stability re-evaluated. The slopes may have to be flattened and other measures taken to stabilize the slopes. Storm runoff should not be allowed to flow EIU & ASSOCIATES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A I 34 Page 10 uncontrolled over the top of cut or fill slopes. One or multiple lines of interceptor trench drains should be installed, as required, on the uphill side of the areas to be graded to intercept and safely drain away surface nmoff and near -surface groundwater flow. Permanent curt slopes or fill embankments should be seeded and vegetated as soon as possible for erosion protection and long -tern stability, and should be covered with clear plastic sheets, as required, to protect them from erosion by stormwater until the vegetation is fully established_ STRUCTURAL FILL f' Structural fill is the fill that supports structural or traffic load. Structural fill should consist of r clean soils free of organic and other deleterious substances and with particles not larger than four inches. Structural fill should have a moisture content within one percent of its optimum moisture content at the time of placement. The optimum moisture content is the water content in the soils that enable the soils to be compacted to the highest dry density for a given compaction effort. The on-site till soils contain a high percentage of fees, and may be used as structural fill only under fair weather condition when its moisture content can be controlled to close to its optimum moisture content. Imported material for structural fill should be clean, free -draining, granular soils containing no more than 5% by weight finer than the No. 200 sieve based on the fraction of the material passing No. 4 sieve, and should have individual particles not larger than four inches. Imported structural fill should be stockpiled and covered separately from the on-site soils. Structural fill should be placed in lifts no more than 10 inches thick in loose state, with each lift compacted to a minimum percentage of the maximum dry density determined by ASTM D1557 Modified Praetor Method) as follows: EIU & ASSOCIATES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A 134 Page 12 A one-third increase in the above recommended allowable soil bearing pressure may be used when considering short-term, transitory, wind or seismic loads_ For footing foundations designed and constructed per recommendations above, we estimate that the maximum total post - construction settlement of the buildbxgs should be 112 inch or less and the differential settlement across building width should be 3l8 inch or less. Lateral loads on buildings can be resisted by the friction force between the foundations and the subgrade soils or the passive earth pressure acting on the below -grade portion of the foundations. For the latter, the foundations must be poured "neat" against undisturbed soils or backfilled with a clean, free -draining, compacted structural fill. We recommend. that an equivalent fluid density EFD) of 350 pcf (pounds per cubic foot) for the passive earth pressure be used for lateral resistance. The above passive pressure assumes that the backfill is level or inclines upward away from the foundations for a horizontal distance at least twice the depth of the foundations below the final grade. A coefficient of friction of 0.60 between the foundations and the subgrade soils may be used. The above soil parameters are unfactored values, and a proper factor of safety should be used in calculating the: resisting forces against lateral loads on the buildings_ BASEMENT AND RETAINING WALLS Basement walls restrained horizontally at the top are considered unyielding and should be designed for a lateral soil pressure under the at -rest condition; while retaining walls free to move at the top should be designed for active lateral soil pressure. We recommend that a lateral soil pressure of 45 and 65 pcf EFD be used for the design of foundation walls with level/descending backslope and rising backslope, respectively; and 35 and 50 pcf EFD for retaining walls with level/descending backslope and rising backslope, respectively_ To counter the active soil or at - rest pressure, a passive lateral soil pressure of 400 pcf EFD may be used, except that the passive pressure within the top 12 inches of the finish subgrade should be ignored. The above passive LIU & ASSOCIATES, INC. November 22, 2004 Proposed 4 -Lot Short Plat L&A Job No. 4A 13 4 Page 13 pressure assumes that the backfill is level or inclines upward away from the walls_ The above lateral soil pressures are tinder the assumption that groundwater behind the walls is fully drained_ To resist against sliding, the friction force between the footings and the subgrade soils may be calculated based on a coefficient of friction of 0.60. The above soil parameters are ultimate values, and proper factors of safety should be used in the design of the basement and retaining wails against sliding and overturning failures. Basement walls or retaining wails may be supported on footiaog foundations seated on or into tate underlying very -dense fresh till or very - hard transitional beds soils, with an allowable soil bearing pressure not to exceed 3,400 psf The is a remote possibility that shallow, stein -type mudflow may occur on the slope above the proposed houses. We recommend that the uphill -side basement walls of the house be extended at least 3 feet above the finish grade to act as debris catchment walls. A vertical drainage blanket consisting of at least 12 -inch -thick free -draining pea gravel or washed gravel should be placed against foundation and retaining walls to prevent accumulation of groundwater behind and buildup of hydrostatic pressure against the walls. The remaining backfill should consist of structural fill constructed per recommendations in the STRUCTURAL FILL section of this report. The top 12 inches of backfili should consist of compacted, clean, on- site soils. The backfill material for the foundation and retaining walls should be compacted with a hand -operated compactor. Heavy compaction equipment should not be allowed closer to the walls than a horizontal_ distance equal to the wall heights. A footing drain, as recommended in the SITE DRAINAGE section of this report, should also be provided for foundation and retaining walls. LIU & ASSOCIATES, INC. November 22, 21144 Proposed 4 -Lot Short Plat LAA Job No. 4A.134 Page 17 variations appear then; we should be retained to re-evaluate the recommendations of this report, and to verify or modify thein in writing prior to proceeding further with the construction. CLOSURE We are pleased to be of service to you on this project. please, feel free to cal] us if you have any questions regarding this report or need further consultation. Yours very truly, LrU & ASSOCIATES, INC. J. S. (Julian) Liu, Ph.D., P.E. Consulting Geotechnical Engineer Exnrpzs 71171 p Six plates attached LIU & ASSOCIATES, INC. s St o,: w 1] ST \' iT rn f n x LnrTlMr Q Lof _ ,(t' R ST 4 lits 3`3`141H -PL ` 2lflli Puirtsrx - SE 218mSr pL$ I r .t \ / . P1 cc VICINITY MAP , WILT & ASSOCIATES, INC. 4 -LOT SHORT PLAT 98M Sl:- 192ND STREET Gmte;hnical Engfneering - EngtneeNng Geology - F-arth Science RENTON, WASHINGTON JOB NO. 4AI34 DATE 11/2012004 PLATE 1 Wilsons 25362-7285 p.2 cn 4 L 11 rn 9 4 A32x$ a27 s;a 208 — 3Q •J i - u` v I cy i., N - _ t220Ta2z ax1.9F F_ #vcro -se as -E aes_a1 • t CR y 4 t k / a - w h w m-8 • I.1 7y J'J? ' z .., k'n Ry " T? g' ~ y a_y-.Jo--' 'v- ZI 72.60' zz-oW _ e; y ZIti r m 2 -SE o Y J 245 w L CY Y pp4tLfrW -6l, µ '' . —T77 c o-, p j• lE 2b 7 26 v , 277T27 T x # q/- 4 X00 M8 4H'M 209- 93 - Jr— r b ® A/ Z PXtCT .. rMTPF71 &GZx Nk1 I 29Z m mow' S6Z 111 t 9L Q SITE AND EXPL-ORAT10N LOCATION PLNN LIII & ASSOCIATE'S, LNC. .' sI 192ND PLAT 98XXS 5: NQ STREP Gootechniosl Englneeing - Engineering ecology- - Eartli science RENTON, WASHINGTON JOB NO- 4A134 1 -DATE 1 ji20121J44 I- PLAN UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUPISYMBOL GROUP NAME GRAVEL CLEAN GW WELL-GRADED GRAVEL, FINE TO COARSE GRAVEL COARSE- MORE THAN 50% OF GRAVEL GP POORLY-GRADED GRAVEL GRAINED COARSE FRACTION GRAVEL WITH GM SILTY GRAVEL SOILS RETAINED ON NO.4 SIEVE FINES GC CLAYEY GRAVEL SAND CLEAN SW WELL-GRADED SAND, FINE TO COARSE SAND MORE THAN 50% MORE THAN 50% OF SAND SP POORLY-GRADED SAND RETAINED ON THE= COARSE FRACTION SAND WITH SM SILTY SAND NO. 200 SIEVE PASSING NO, 4 SIEVE FINES Sc CLAYEY SAND FINE- SILT AND CLAY INORGANIC ML SILT GRAINED LIQUID LIMIT CL CLAY SOILS LESS 7E-lAN 50% ORGANIC OL ORGANIC SILT, ORGANIC CLAX MORE THAN 50% SILTY AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT PASSING ON THE LIQUID LIMIT CH CLAY OF HIGH PLASTICITY, FAT CLAY NO. 2I]0 SIEVE 50% OR MORE ORGANIC OH ORGANIC SILT, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT AND OTHER HIGHLY ORGANIC SOILS NOTES: SOfL MOISTURE MODIFIERS: 1. FIELD CLASSIFICATION IS BASED ON VISUAL EXAMINATION DRY - A13SENCE OF MOISTURE, DUSTY, DRY TOOFSOILINGENERALACCORDANCEWITHASTMD2468-83, THE TOUCH 2. SOIL CLASSIFICATION USING LABORATORY TESTS IS BASED SLIGHTLY MOIST- TRACE MOISTURE, NOT DUSTY ON ASTM D24$7-83. MOIST - DAMP, BUT NO VISIBLE WATER 3_ DESCRIPTIONS OF SOIL DENSITY OR CONSISTENCY ARE VERY MOIST -VERY DAMP, MOISTURE FELT TO THE TOUCH BASED ON INTERPRETATION OF BLOW-COUNT DATA, VISUAL APPEARANCE OF SOILS, ANDIOR TEST DATA WET- VISIBLE FREE WATER OR SATURATED, USUALLY SOIL IS OBTAINED FROM BELOW WATER TABLE LIU & ASSOCIATES, INC. UNIFIED SOIL CLASSIFICATION SYSTEM GPdechnical Engineering • Engineering Ge0b9y Earth Science PLATE 3 TEST PIT NO. 1 TEST PIT NO. 2 Logged By: JSL Date: 1 111 412 00 4 Ground t=i. 240.0,:j Depth USCS Sample W Other R. CLASS. Soil Description No. % Test OL I Berry bushes and duff on surface 1 Dark -brown, loose, organic, silty fine SAND, occasional cobble and boulder, fine roots, moist (TOPSOIL) z 3 SM Brown, loose, silty fine SANDt few roots,";T 4 5M Light -brown, medium -dense, slJty fine SAND, trace gravel snot 5 occasional cobble and boulder, slightly mois! (ABLATION TILL) 6 Light -brawn, fine -to -medium -grained SANDSTONE, moist 7 (BEDROCK) B 9 Test pit terminated at 8-0 ft, groundwater not encountered. 10 LIU & ASSOCIATES, INC. GeatechNcai Engineering Engineering Geology - Earth Science TEST PIT LOGS 4 -LOT RESIDENTIAL DEVELOPMENT 98XX SOUTH 192ND STREET RENTON, WASHINGTON JOB NO, 4A134 fDATE 11/15104 IPLATE 4 Logged By: JSL Date: 11/14/2004 Ground EI, 220.0't Depth USC5 Sampre W Other ft. CLASS. Soil Description No. % Test OL Berry bushes, iresh and duff on surface 1 Dark -brown, loose, organic, silly fine SAND, with roots to '1 -inch diameter moistOPSQJL? 2 SMISP Brown, loose to mediurn-dense, slightly silty, fine to medium SAND, with roots to 6 -inch diameter, moist (ABLATION TILL) s SM Light -brown to light -gray, dense to very -dense, silty fine SAND, 4 trace to some gravel, weakly -cemented, slightly moist LODGMONT TILL) 5 r 7 Test pit terminated at 6.0 ti, groundwater not encountered, 9 u TEST PIT NO. 2 Logged By: JSL Date: 1 111 412 00 4 Ground t=i. 240.0,:j Depth USCS Sample W Other R. CLASS. Soil Description No. % Test OL I Berry bushes and duff on surface 1 Dark -brown, loose, organic, silty fine SAND, occasional cobble and boulder, fine roots, moist (TOPSOIL) z 3 SM Brown, loose, silty fine SANDt few roots,";T 4 5M Light -brown, medium -dense, slJty fine SAND, trace gravel snot 5 occasional cobble and boulder, slightly mois! (ABLATION TILL) 6 Light -brawn, fine -to -medium -grained SANDSTONE, moist 7 (BEDROCK) B 9 Test pit terminated at 8-0 ft, groundwater not encountered. 10 LIU & ASSOCIATES, INC. GeatechNcai Engineering Engineering Geology - Earth Science TEST PIT LOGS 4 -LOT RESIDENTIAL DEVELOPMENT 98XX SOUTH 192ND STREET RENTON, WASHINGTON JOB NO, 4A134 fDATE 11/15104 IPLATE 4 LIU & ASSOCIATES, INC. Gentechnical Engineering . Engineering Geology - Earth Scienm TEST PIT LOGS 4 -LOT RESIDENTIAL DEVELOPMENT 98XX SOUTH 192ND STREET PENTON, WASHINGTON JOB NO- 4A134 TDATE 111151(}4 IPLATE TEST PIT NO. 3 Logged By: JSL Date: 11/1412004 Ground El. 237.0' Depth VSCS Sample W Other ft. CLASS. Soil DeScri tips No. % Test OL Berry and fern bushes and duff on surfaoe t Dark -brown, loose, organic, silty fine SAND, occasional cobble, with fine roots, mast OPSDI 2 SM Brown -gray, dense to very -dense, silty fine SAND, with chunks of sandstone fragments mixed in, weakly cemented, moist 3 LODGMONT TILL) 4 5 fi 7 Test pit terminated at 6.5 ft, groundwater not encountered. 9 74 TEST PIT NO. 4 Logged By: JSL Date: 1111412004 Ground EI. 226.5' t Depth I uses Sample w Other ft. CLASS. Soil Description No_ % Test OL I Berry bushes, trash and duff on Surface 1 Dark -brown, loose, vrganle. silty fine SAND, abundant roots to 6 -Inch diameter, moist (TOPSOIL.) 2 W Brown, medium -dense, silty fine sand, trace gravel, slightly moist ABLATION TILL) 3 4 5 SM Light -brown, dense to Very -dense, silly fine SAND, trace fine gravel, weakly -cemented, slightly moist (LODGMONT TILL) s r t Test pit terminated at 6.0 ft,.grpundwater not encountered. h LIU & ASSOCIATES, INC. Gentechnical Engineering . Engineering Geology - Earth Scienm TEST PIT LOGS 4 -LOT RESIDENTIAL DEVELOPMENT 98XX SOUTH 192ND STREET PENTON, WASHINGTON JOB NO- 4A134 TDATE 111151(}4 IPLATE TEST PIT NO. 5 Logged By. JSL Date: 11/14/2004 Ground El. 224.0' ± Depth ft. uSGS Sample GLASS. Soil Desai 110;7 tvo. USCS CLASS. Soil De5O tion Sampre w No. % other Test OL Berry bushes on surface 1 moist (TOPSOIL) Dark -brown, loose, organic, silty fine SAND, vrith fine roots, 2 2 SM oisf {ZOPSOIL) Light -brown to tan, medium -dense, silty fine SAND, trace gravel, 8 cobble and boulder, moist (ABLATION TILL) dahily mit ABLATION TILL) 4 3 SM Light -brown to light -gray, very -dense, silty fine SAND, trace gravel, SM Light -brown to light -gray, very -dense, silty fine SAND, trace gravel, cemented, slightly moist (LODGIUONT TILL) s cemented, moist (LODGMONT TILL) 4 7 6 a 9 Test pit terminated at 7.0 fl, groundwater not encountered. to s 7 Test pit terminated at 5.0 ft, groundwater not encountered. 8 9 0 Logged By: JSL TEST PIT NO. 6 Date: 11114/2004 Ground EI. 230.8' t DWh ft. uSGS Sample GLASS. Soil Desai 110;7 tvo. W Other Test OL Berry bushes on surface i Dark -brown, loose, organic, silty Tine SAND, With tine roots, moist (TOPSOIL) 2 SM Light -brown, medium -dense to dense, silty fine SAND, occasional 8 cobble and boulder, moist (ABLATION TILL) 4 5 SM Light -brown to light -gray, very -dense, silty fine SAND, trace gravel, s cemented, moist (LODGMONT TILL) 7 a 9 Test pit terminated at 7.0 fl, groundwater not encountered. to LIU & ASSOCIATES, INC. Geotechnical Engineering - Engineering Geology Earth Science TEST PIT LOGS 4 -LOT RESIDENTIAL DEVELOPMENT 98XX SOUTH 992ND STREET RENTON, WASHINGTON JOB NO. 4A134 JDATE 11115104 IPLATE all City of NOTICE OF ENVIRONMENTAL DETERMINATION AND PUBLIC HEARING ISSUANCE OFA DETERMINATION OF NON -SIGNIFICANCE - MITIGATED (UN5-M) POSTED TO NOTIFY INTERESTED PERSONS OF AN ENVIRONMENTALACTION PROJECT NAME: Wilson Park 2 Prebnninsry Plat PROJECT NUMBER: 1L 4XL2, E6, PP, PPUD LDCAnQ*: 698 S 5S* Street D{SCIUMON: The applicant prapoe. to eubdi"de an aehtlnd 2,25 ane panel IMo to i= for the eventual development of detached single Family homes, ansa 2 trad for open sPaca. The she 4 zoned Resldendal -14 d.l. IR -14) S RnW.ndd - 1 do/ec IA -1)- The site sontalm 9,763 0. of protested alnpes f>40%). Proposed derelty averaAea 6A dwellingaunnaperse across the she, with 4 Ion proposed In the R-14 area, & 1 lot Propoeed within the R -L A Planned Urban Development Is proposed In order to rnodfly minimum Ion sue within the R-1 zone and Provide larger lots within the R-14 — Asreu would be provided from South 5514 Street els new street mrntrur d as Part of the aper -rd wfbm Park 01 plat A small hydrologically holated, unaMreaulneed wetland Is latad the western Portion of the site. The Site Wreeire 62 tree,, of wNch 21 WouW K nomad for the amtrectson of the new St et oaring Wilson Park RL Ten (10}trees would be retained, and new trees would be Planted IWJWing 2 new trees par IoL The project requires Em4re,m Mal ISE" Aavlew, Planned Urban Development (PUD) Rvhi , and Preliminary Plat Wr THE CIT' OF RENTON ENVIRONMENTAL REVIEW COMMITTEE (ERC) HAS DETERMINED THAT THE PROPOSED ACTION DOES NOT HAVE A SIGNIFICANT ADVERSE IMPACT ON THE ENVIRONMENT. Appeals of the en tnerental determinatlon mutt be filed In writing on or before SOD p.m. on May 25, 20M Logmher whh She required fee with: Heatng Examiner, City of Renton, 1955 South Grady Way, Renton, WA 98057- APP"Is to the Emminer art governed by City of RMC 44-110. Addltlonal Information regardingth. appeal process mey be obtained from the Renton Clty Berl; s ONloa, 1425) 4366510. A PUBLIC HEARING WILL BE HELD BY THE RENTON HEARING ID(AM14ER AT HIS REGULAR MEETING IN THE COUNCIL L34AMBERS ON THE 7TH FLOOR OF CITY HALL, 1055 SOUTH GRADY WAY, RENTON, WASHINGTON, ON JUNE i1, 2012 AT UWO AM TO CONSIDER THE PRELIMINARY PLAT AND PRELIMINARY PLANNED URBAN DEVELOPMENT. IF THE ENVIRONMENTAL DETERMINATVN 15 APPEALED, THE APPEAL WILL BE HEARD AS PART OF THIS PUBLIC HEARING. FOR FURTHER INFORMATION, PLEASE CONTACTTHE CITY OF RENTON, DEPARTMENT OF COMMUNITY & ECONOMIC DEVELOPM ENT AT (4251430-7200. DO NOT REMOVE THIS NOTICE WITHOUT PROPER AUTHORIZATION Please Include the project NUMBER wheel calling for proper ftle Identification. CERTIFICATION hereby certify that.. —copies of the above document were posted inconspicuous places or nearby the described property on Date: i f l ' 1 v Signed: STATE OF WASHINGTON ) SS COUNTY OF KING } r certify that I know or have satisfactory evidence that. , signed this instrument and acknowledge it to be his/her/their freeland voluntary act for the 1 l uses and purposes mentioned,1// 1 ilrr iik ent. Dated: i t Y t ~ Public in PU C 0,tary Ont}: M'g i 16 Aires: r t/Jl/1i the State of Washington EXHIBIT 19 CITY OF RFNTON DEPARTMENT OF COMMUNITY & ECONOMIC DEVELOPMENT- PLANNING DIVISION AFFIDAVIT OF SERVICE BY MAILING On the 9th day of May, 2012, 1 deposited in the mails of the United States, a sealed envelope containing ERC Determination documents. This information was sent to: Name Representing Agencies See Attached Darrell Offe Contact Robert & Doravin Wilson Owners Steve McNamee Party of Record Paul & Freida Witt Party of Record Jonathan Vu Party of Record Khanh Nguyen Party of Record Quang Dang & Kim Duong Party of Record Signature of Sender): STATE OF WASHINGTON SS COUNTY OF KING ' certify that I know or have satisfactory evidence that Stacy M. Tucker signed this instrument and acknowledged it to be his/her/their free and voluntary actic{r: 4es acrd pur oscs mentioned in the instrument. a Dated: 1 otary Pubic in and forl4e State of Chas}r;t„ f' Notary (Print): My appointment expires: Project Name: Wilson Park 2 Preliminary Plat & PUD Project Number: LUA12-013, ECF, PP, PPUD template -affidavit of service by mailing Altmann Oliver Associates, LLC AOA March 11, 2011 Bob Wilson 21703 — 60"' St. E. Lake Tapps, WA 98391 fHli 12.i,.3.,-t...i# on Dvision s'# h:rnisilcslI 11 N,llllill7' & lrcflitc r[tis'c AOA -3796 SUBJECT: Wetland Verification for Wilson Park 2 (Parcel 312308-9119) City of Renton, WA (File # PRE11-004) Dear Bob: On March 1, 2011 1 conducted a wetland reconnaissance on the subject property utilizing the methodology outlined in the 1997 Washington State Wetlands Identification and Delineation Manual. The primary focus of the reconnaissance was to verify the results of the wetland determination report prepared by Alder NW (dated October 19, 2004). The Alder NW report indicated a small (less than 800 s.f.) hydrologically isolated wet area in the western portion of the site, immediately adjacent to the remnant foundation of a large old loafing shed. Since the soils within this portion of the site have been significantly disturbed, and the small marginal area appears to have been created during historic site grading adjacent to the old shed, the Alder NW report determined the feature to be unregulated. Based on my wetland reconnaissance, I concur with the findings of the Alder NW report that the area consists of a small (well under 2,200 s.f.) hydrologically isolated Category 3 wetland. Small hydrologically isolated Category 3 wetlands are exempt from the City's critical area regulations if they meet the following provisions of RMC IV-3-050.C.5.f. 1) Standing water is not present in sufficient amounts, i.e., approximately twelve inches (12' to eighteen inches (18") in depth from approximately December through May, to support breeding amphibians; EXHIBIT 20 Bob Wilson March 11, 2011 Page 2 At the time of the March 1, 2011 field investigation, soils within the wetland were generally saturated near the surface and ponding was limited to depths of about 2 inches within scattered disturbed pockets. Since ponding is restricted to small very shallow isolated pockets, this provision has been met. 2) Species listed by Federal or State government as endangered or threatened, or the presence of essential habitat for those species, are not present; The wetland does not contain any species listed by Federal or State government as endangered or threatened, nor does it contain essential habitat for those species. 3) Some font of mitigation is provided for hydrologic and water quality functions, for example, stormwater treatment or landscaping or other mitigation; and It is my understanding that as part of the proposed project, all runoff from impervious surfaces on the site will be treated and retained prior to downstream discharge. 4) A wetland assessment is prepared by a qualified professional demonstrating the criteria of the exemption are met. The wetland assessment shall be subject to independent secondary review at the expense of the applicant consistent with subsection F7 of this Section. I have conducted a secondary review of the Alder NW report and have verified that all of the criteria of RMC IV -3-050.C.51 have been met. In addition to the wet area, the Alder NW report also describes a drainage course that flows from east to west through the southern portion of the site. As identified in the report, this drainage originates at the top of the slope from an outfall of a storm drain line which collects surface water runoff from S. 192nd Street. Since this artificially collected runoff is conveyed within a channel where no channel previously existed, it also should not be subject to critical area regulation. Conclusion Pursuant to an on-site reconnaissance, the findings of the Alder NW report were confirmed and no regulated wetlands or streams were identified on the property. Bob Wilson March 11, 2811 Page 3 If you have any questions regarding the reconnaissance or verification of the Alder NW conclusions, please give me a call. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC LDjrt__ John Altmann Ecologist CC: Steve Beck N- LI!T October 19, 2004 Project No. 42204 Mr. Karl Singh 5218 Talbot Road ,South Renton, Wa0ington 98055 Subject: Site Evaluation Singh -Property South 192nd Stmt at 98th Avenue South Reran, Washington Parcel # 3123059119 Dear W. Singh As requested we have' a site zvah ation for tha gropcq low on the north side of South 192nd Stma at 98th Anemic South in the City of Renton. -1t is identified as King County Parcel #3123059119. The location of the propeaty is shown on the Vicinity Map (Figure 1). The purpose of this work was to conduct a site evaluation to detam ire if wetlands or ofl r surface water futures are preseut on the property, In conducting cur site evaimatoa to identify possi-ble wetland areas we fllowcd the general procedures for the rotrtine on - she -methodology as outlined in the March 1997 Washington Mate Wedands Identfication and Deltneatlon Mwwl, prepared by the Wasbingtrm Stale Department of Ecology. This procedure iavolves anatysis of vegetation patterns, soil conditions, and near -surface hydrology in making a determination of wetland conditions. This meffieWagy is similar to the procedures outlined in the Corps of Engineers Wetkmd Dehneatdon Manual TechM crd Report Y-871(1987). Our scope of work included a site visit on September 73, 2004, at which time we completed our site evaluation- The appro33mate location of the wetbna.d is iilusftWad on the Site Map (F re 2)_ PROCEDURES For the purpose ofthis study, we used the wetland definition adopwd by the Environm=W FroUcdon Agency (EPA) and the Army Corps of EaSineers (COE) for adtiistezing Section 404 of the Clean Water Act. Aocarciing to this definition, wetlands are: Those areas that are inundated or satuwod by surface water or groum1wacr at a frequency and duration sufficient to support, and that under normal arcs mstances do support, a prevalence of vegetation typically adapted for life in saturatod soil coaditiom. Wetlan& gcaraally include swamps, marshes, bogs, and ftilaC areas. (33 CFR 3231 In Washington State, the Shoreline Management Act and Growth Mang-== Act live amended tip definition to esdude some wetland dblati by adding ttu following sentences to the wetland defiaitiow 518 North 59m Street. seaTde, Washlmjton 98103• Phone (206)783-1036 entrap alderrrw0comca5t.net Mr_ rayl sin& October 19, 2044 Wetlands do not include those artificial wetlands interbonally created frown non -wetland sites, including but not limited to, irrigation and drainage ditches, grass -lined swales, canals, demon facilities, wastewater tient facilities, farm ponds, and landscape amenities, or those wetlands created after illy 4 1990, that were intentionally.created as a res A of the conatruction of a road, street or Highway. Wetlands may is tude those ardfcial wetlands imtunonally created from non- wedand areas to rugate the conversion of was. In a.ocordauce with this definition, a given area is dcs4psawd as jurisdictional wetland if the hydrology results in im ndated or saturated soils during -the growing season, hydric soils are prescr, and tho dominad vegetation is hydrophytic. Delineation procedures are based on diagnostic enviromuenW indicators of wetland vegetadeA, wetland sods, and wetUnd hydrology. By deimition, an area is designated as wetland octan there ora positive indicators for aIL throc Parameters. A listing of plant species has been developed for use in the methodology for delineating wetland areas." 'Phis listing assigns phut species to one of five indicator status ratcgorics rouging from Obligate wetland species, which almost always occur in. wetlands. to Upload species, which rarely aeca in wetlands. Under normal conditicros, hydrophytic vegetation is dstermincd to be press d if more thaw 50 percent of the dominant species arc in the Obligate (URL), Facultative Wetland (FACW), or Facultative (FAC) mdicater categories. Diagnostic indicators of hydric soils are related to soil sat m tim which leads to mmeivbie coaditim in the soil. Under these condi ions, decomposition of organic material is inhibited and sod minerals are reduced, creating clzmwWristic soil colors that can be grant ficd by comparisau with Mmseli Sod Color Charts. A ch m a of nae or less in umnoWed soils or a chroma. of two or less in motdod soils generally indicates a hydric soil. In additioir, sons that are saturated during the growing seasoti satisfy -a criterion for hydric soils. We used a hand auger to collect soil samples from a depth of 8 to 15 inches. Wetland hydrology is defined as wed or saturated soil conditions for at least 14 consectithe days during the growing season. If no water is present at the tone of evaluation, other indicators my incinde topographic low points or c mmels, flood debris, complete absence of vegetation, or pm=cc of hydric soils. Standardized data forms are available to record observations on each parameter. For ilriss project, we completed data farms for the Routime On -Site Deterrninadon Method at 3 locations on the site. Copus of these data Ennis are included with this report. SITE CONDMONS The subject property is an irregularly shaped property with an area. of.appradmately 2.1.5 acres. Al present the site is undeveloped and is occupied by a mdced forest and. The property to the north is cantly undeveloped and is shnilarly occupied by mixed forest stand Adjacent properties to the east, west and off the northwest corner of the property are occapled by existing =Fft family homes. TopograpbicaW. the property generally slopes steeply down from the east property line at about elev. 298 to a slightly' sloping bench whiob slopes down £turn about elev. 240 to about elev. 220.at the west property line 71 is somewhat flatter area occupies approximately the western third of the site, Vegetation on the more steeply sloping eastera two thirds of the property is cbarxcriaed as mixed mann mixed forest: Predan ra a trees present are Douglas fir (Pseudotsuga nwndesti), and big leaf maple (Acer mucrophyllum), with scattered black cottorm-ood (Populus balsamiftra)'and red alder (Alnus rubra) trees prewnt closer W the We of the steep slope. The predwainant undetstoay shrub species is Oso plum (Oemleria cera sifonnisl with sword £eta (Pc&sdch= munitum) as the predominant herbaceous species. Himalayas blackberry (Rubes dircolor) is present at the margins of the forested area where there had been some clearing. ' Project No. 9=4 Page No. 2 Mr. Kass single 4ctobcr 19, 2044 There has appw= ly been some grading and clear on the Cower bench area. Vegetation here is dominated by Hbnalayaa blwlcbcrry gr m1h. There are scattered tall buck Cottonwood big Imf maple and Douglas fir with dmst-- small red alder and black cottonwood along the toe of the slope whemtbere appears to have been more recent clearing We identified a small isolated area where there appears to have been sballow surface water earlier in the year. Vegetation can this small isolated area includes creeping buttmuup (Ramowulus repo=), a small patch of soagh sedge " (Aex obnuPWX willows (Salix spp.). Conditions within this small area are described on Data Foran 3. `ibis small depression has a width of less than 15 feet and length of approximately SO $. As such it has a tatal area of less than 800sq$ It is mvcgukited under City of Rentan segpWons. _ We also =m=d the drainage course mmnmg across the south side ofthe property. 'ibis drainage cnWrtates at the top of the steep slope as the outfall from a stazm drain Iron which colleen sum water runoff from South 192nd Strcct Directly below the storm brain outfaR at the top of the slope ire is a deeply eroded, stew sided channel, At the upper end the eroded channel is 3$ to Oft in,depth Further down the slope the olsannel depth decreases and the channel becomcs Less well deed. Vegetation over the channel is dominated by Dayan bla cicbmy. There is a catch basin at the base of the slope within the South 192nd Street rcad shoulder. This catch basin collects surfzrce water from the road side ditch along the north side of South 192nd Street as weft as sar&oc water reaching the . bottom of the slope in the drainage channel. . There is no evidence of a naturally occunimg topographic suale.which aught have carried a naturally 0==g se sozial streaEtr, eitherp slope fr filegmgerty ar t ie`sl"raenage-crosses the subject propezty. T is am i erpn atioa that ins drainage is an artificially generated drainage channel resulting from construction of South 192nd street and the dis_cbwge of road may storm runoff onto the top of the slope. As as artificially generated drainage channel it sh not be subject to regulation. We trust the infonration presented is sufficient far your current needs_ If you have any questions or soquire additional infosrnaticr please ca.H. Sincerely yours, ALDERNW C'raret P. Munger Project Scientist Enc€-- Data Forms (3) Vicinity Map — Figure .I Site Mala — Figure 2 Project No. 922Q4 Page Na 3 DATA FORM ROUTINE ON-SITE WETLAND DETERMINATION D feral Site Site is generally foresteA on steep slope Data Poing DP -1 Candions: Site Disturbance? West and of site cleared with some grading in the Locatim See site MaP vast VEGETATION 1-4 o Eg Dominant Pert Species Dmrivant Plain Species 1 polus trichocarpa Fuc T S Z Satix sp. Fac S 9 3 Rub usdiscoior rlpl S in 4 ph Facw H 11 5 12 6 13 7 14 0 - Percent of dominam species that are OBI, IFACW, anchor FAC: 75 Is the hrhophytic vegetation criterion rpt? Yes Rabon2le: Mare titer SO%species hydrophyttc SOIL Soil Type: Aidu ood Hydric Sails List No Ifistic Epigedon? Na Moines? Slight Gieyod? No Matrix Color: 1.5Y5/3 Iliotile Calcis: Dom: 12" ether byddo sod indicators: iVo Is riot hydric, s criterion met? No Rationale: [ 'hroma greater than 2 HYDROLOGY Is the around surface irmmdated? No Surface water dwft Is the soil saxuratod? No Depth to free-standing w dw i a probe hole: Not in upper I8" Other field evidence b:yc mlW Na Is Phe wWaud hydrology critcri(M mst? No Rafiama e: No Evidence ofsoft saturation WETLAND DETERMWATION Are wetly criteria met? No R.adunale for wetland deeisim Nati hydrk soil no evidence of long term sofa saturations Pmje ct Name: SMA Renton Property AlderNW Field lnyesdgatar(5): G. murnger 518 North 591h Street Project Na: - 92204 Date: 9123/04 Sebe, WasWngtm 98103 DATA FORM ROUTINE ONSITE AVETLAND DETERMINATION Denri-be Gmral Site Conditions: Site is generally forested on steep slope Data Point No.: DP -2 Site Disturbance? Evidence ofpart clearing and some grading. Location_ see site map VEGE'T'ATION Fervent of domm= species ftt are OBL, FACW, andlos FAC, Is the hYdr hyac vcgd=oa criterion met? Yes Soil Tl pe: Alderwaod I btk Epipedon? X0 5 Rationale: More than 50% species hydrophytic SOIL Hydric .Soils Gist: Modes? AS Matrix {:Dior. 2.5Y5I2 Motdc Colors: Other hydric soil indicators: Pomible seasonal siandirg water Is the hydric sog Criterion met? Yes Rationale: _ No Gleyed? No Depth 12„ rAronra 2 with motiles H"ROLOGY Is the graamd suufa.oc b undatod? No Surface water depth: Is the sod saturated? No Depth to free-standing water in probe We: Not in upper 18" Otbj= field evidence h)*oloW Ewdence ofpoadble stard}ng mater Is the wetland hydrology m4crionait? ? Rationale Presumed on basis of and and sugges6an of Seasonal surface water: WETLAND DETERMINATION Are inland Criteria met? Yes Rationale for weF]and decision: P=bvff indicators for each pw=etcr Prtect Name: Singh RAnton Property Alderl+lW Field InvestigmmAs): G. Maireger 518 North 591h Street Project No.: 92204 Date: 4/23104 SeatEle; Washington 98103 Dominan Phmt Species Daunt Plant Species 1 Carer obmpta ON H 8 Z RommCwhis repena F=W H 9 3 Rubus discolor UPI S 10 4 Populus trrchocarpa Fac T 11 5 12 6 13 7 I4 Fervent of domm= species ftt are OBL, FACW, andlos FAC, Is the hYdr hyac vcgd=oa criterion met? Yes Soil Tl pe: Alderwaod I btk Epipedon? X0 5 Rationale: More than 50% species hydrophytic SOIL Hydric .Soils Gist: Modes? AS Matrix {:Dior. 2.5Y5I2 Motdc Colors: Other hydric soil indicators: Pomible seasonal siandirg water Is the hydric sog Criterion met? Yes Rationale: _ No Gleyed? No Depth 12„ rAronra 2 with motiles H"ROLOGY Is the graamd suufa.oc b undatod? No Surface water depth: Is the sod saturated? No Depth to free-standing water in probe We: Not in upper 18" Otbj= field evidence h)*oloW Ewdence ofpoadble stard}ng mater Is the wetland hydrology m4crionait? ? Rationale Presumed on basis of and and sugges6an of Seasonal surface water: WETLAND DETERMINATION Are inland Criteria met? Yes Rationale for weF]and decision: P=bvff indicators for each pw=etcr Prtect Name: Singh RAnton Property Alderl+lW Field InvestigmmAs): G. Maireger 518 North 591h Street Project No.: 92204 Date: 4/23104 SeatEle; Washington 98103 371UV DATA FORM ROUTINE ONSITE WETLAND DETERMINATION Describe General Site con&tions: Data Point No.: DP -3 Site Disturbawe? Evh*nce ofpast clewing and some grading Location: See site map VEGETATION Dommurt Plant Species Domit Plant Species I Pop dus mckocarpa Fac T 8 2 Ruims rttswtor UPI H 9 3 to 4 ll 12 6 13 7 14 Peroent of dominwt species t]zat are OBIS FACW, andlor FAC: SQ Is the hydrophytic vegetatam criterion met? yes Monale: 1 50% species hy&0PkdC No herbaceous cover below dense hlac* e= Soli Type: Alderwood Hist u Epipedw? No Matrix Color. IOYR413 Other hydric sail fixU rocs: No Ls the hydl soil criteaon met? No Is the ground Sur&ze incada ? Ivo Hydric Soils List: No Mottles? Yes Gleyed? No Mottle Colors: - Depth: IZ ,. l smale: Chroma 3, HYDROLOGY Surface water depth: Is the soil satwated7f MO Depth to free-standing v ater in probe hole: Qthor field evidence hSdrology No Is the wWand bydmlW ==On met? No Rat=ale No evidence of owdaiion or sal saturation WETLAND DETERARNATION Ase wetland criteria met? Na R wiorcak .for wetland decisk= Non hydric 5014 no evidence of long term soil satTudan or mandatlon Project Nam- Singh Rerr In Property AidcrNW Field Investigator(s):nger 518 Nodh 59th StreetCr.G Iii Project No- 92204 Date: SlZ3l[l4 Seale, WasbiDgm 98103 VACINrfY MAP ALDERKad Singh Property I Renton, Washington No.92204 I Date Oct., 2004 1 Figure 1 0 DP -1 Approximate Data pclnt Coco-tior FENCE COR j5 (751 W. 3 t N. JF PRO'. W 2O APPROXIMATE SCALE 50 0 1% 100 feet o59 -as SITE MAP Karl Singh Property Kent, Washington Proj. No. 30102 February 28, 2012 Of l3rI op"t ADDENDUM TO "TECHNICAL INFORMATION REPORT" Prepared for Wilson Park (LUA09-140) By Baima & Holmberg, Inc. dated May 5, 2009 Prepared By: Darrell Offe, P.E. EXHIBIT 21 eoh`a l , ro l6 - I. OVERVIEW The proposed Wilson Park #2 is a 10 lot single family residential subdivision situated on 1 existing lot with a total area of 2.15 acres. It is located on the north side of South 55"' Street at Ph Avenue South, when extended. The project was part of an earlier submittal called Wilson Park (LUA09-140). The property was evaluated for development of a road and utilities to access Wilson Park. The Technical Information Report prepared by Baima & Holmberg dated May 5, 2003, discusses the onsite areas, off site drainage systems, and evaluates the downstream drainage system. This report is provides the necessary preliminary review of the drainage system for Wilson Park #2. As part of the report, a stormwater treatment system was proposed within the roadway at the entry of the new road and South 55''. This system was only sized, at that time, for Wilson Park and the road improvements on Wilson Park #2. Additional impervious areas will be added to this treatment system with the addition of 10 lots within Wilson Park #2. Attached within this addendum are calculations that are intended to be a starting point for sizing the storm treatment facility for the two projects. Under the 2009 City of Renton Drainage Manual, Best Management Practices (BMP's) are required to be used for new developments. One of these BMP's is restricting the impervious areas on the future lots to help reduce runoff, mitigate for development, and minimize the treatment system needed for the project. This Restrictive Covenant provision was utilized as part of a preliminary sizing of the future system for both projects. It is anticipated that the two projects will occur (be developed) simultaneously. A review of the two developments utilizing a 3,300 square feet of impervious area per lot created the proposed stormwater vault shown on the Drainage/Utilities Plan. Based upon experience developing building footprints and impervious areas on building permits of similar size lots, 3,300 square feet gives the future builder plenty of impervious coverage for the home, patio, driveways, and walkways. Once the final engineering plans are developed and cost evaluations are reviewed for this facility, restricting the lots further is an option to minimize the facility needed. This is a preliminary review of a possible scenario that a future developer can use. PRELIMINARY CALCULATIONS BREAKDOWN OF BASINS Total rill rill Area Grass I Forest Notes SITE 4.60 ac 0.00 ac 1 4.60 ac KCRTS Input Parameters 4.60 ac SITE Total .' Area Max ' Imperviousl Design' Impervious Till y Grass Till r' Forest Notes Public RNV 40,684 sf 32,547 sf 8,137 sf Open Space 31,093 sf 31,093 sf Lot 1 (WP) 4,594 sf 3,446 sf 3,400 sf 1,194 sf Lott 4,500 sf 3,375 sf 3,400 sf 1,100 sf Lot 3 5,896 sf 4,422 sf 3,400 sf 2,496 sf Lot 4 5,993 sf 4,495 sf 3,400 sf 2,593 sf Lot 5 5,979 sf 4,484 sf 3,400 sf 2,579 sf Lot 6 5,964 sf 4,473 sf 3,400 sf 2,564 sf Lot 7 6,782 sf 5,087 sf 3,400 sf 3,382 sf Lot 6,269 sf 4,702 sf 3,400 sf 2,869 sf Lot 9 5,400 sf 4,050 sf 3,400 sf 2,000 sf Lot 10 5,400 sf 4,050 sf 3,400 sf 2,000 sf Lot 11 5,404 sf 4,053 sf 3,400 sf 2,004 sf Lot 12 8,122 sf 6,092 sf 3,400 sf 4,722 sf Lot 1 (WP2) 5,775 sf 4,331 sf 3,400 sf 2,375 sf Lot 2 5,905 sf 4,429 sf 3,400 sf 2,505 sf Lot 3 5,905 sf 4,429 sf 3,400 sf 2,505 sf Lot 4 5,905 sf 4,429 sf 3,400 sf 2,505 sf Lot 5 5,909 sf 4,432 sf 3,400 sf 2,509 s Lot 6 5,586 sf 4,190 sf 3,400 sf 2,186 sf Lot 7 5,560 sf 4,170 sf 3,400 sf 2,160 sf Lot 8 5,560 sf 4,170 sf 3,400 sf 2,160 sf Lot 9 5,559 sf 4,169 sf 3,400 sf 2,159 sf Lot 10 6,778 sf 5,084 sf 3,400 sf 3,378 sf Totals {Sq. Feet} 200,522 sf 107,347 sf 62,082 sf 31,093 sf Totals (Acres) 4.60 ac 2.46 ac 4.43 ac 0.71 ac KCRTS Input Parameters 1) Wdrn urn Im pervious calculation - R-8 (75%) 2) Design Impervious - Restricted impervious area by Restrictive Covenant Existing Site Conditions Land Use Time Series: PreDev.tsf ]7 Compute Time Series Modify User Input File for computed Time Series I.TSF] Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-'Fac Annual Peak Till Forest Flow 4.60 acres; Till Pasture Rank 0.00 acres Till Grassj Peaks 0.00 acres Outwash Forest Proh 0.00 acres! Outwash Pasture; 0.00 acres Outwash Grassi 0.00 acres' Wetlandl 0.00 acres, Impervious; 0.00 acresl Total — 1 f3fI 4.60 acres Scale Factor : 1.00 Hourly Reduced Time Series: PreDev.tsf ]7 Compute Time Series Modify User Input File for computed Time Series I.TSF] Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-'Fac Annual Peak Flow Rates--- Flow Frequency Analysis------- Flow Rate Rank Time of Peak Peaks Rank Return Proh CFS) CES} Period 0.290 2 2/09/01 18:00 0.371 1 100.00 0.990 0.079 7 1/06/02 3:00 0.290 2 25.00 0.960 0.215 4 2/28/03 3:00 0.223 3 10.00 0.900 0.008 6 3/24/04 20:00 0.215 4 5.00 0.800 0.128 6 1/05/05 8:00 0.188 5 3.00 0.667 0.223 3 1/18/06 21:00 0.128 6 2-00 0.500 0.188 5 11/24/06 4:00 0.079 7 1.30 0.231 0.371 1 1/09/08 9:00 0.008 8 1.10 0.091 Computed Peaks D.344 50-00 0.980 Developed Site Conditions Land Use Area Till Forest 0.71 acres! Till Pasture# 0.00 acres' Till Grassi 1.43 acres Outwash Forest 0.00 acres} k Outwash Pasture{ 0.00 acres# Outwash Grass, F 0.00 acres! Wetland' O.DO acres Impervious 2.46 acres( 4.60 acres! Scale Factor: 1.00 Hourly Reduced Time Series: C]ev.ts4 I ?l Campute Time Series Modify User Input File for computed Time Series [.TSF] Flow Frequency Analysis Time Series File:dev.tsf Project bocation:Sea-Tac Annual Peak Flow Rates--- Flow Frequency Analysis ------- Flow Rate Rank Time of Peak Peaks Rank Return Prob CFS) CFS) Period 0.752 6 2/09/01 2:00 1.52 1 100.00 0.990 0.602 8 1/05/02 16:00 0.930 2 25.00 0.960 0.899 3 2/27/03 7:00 0.899 3 10.00 0.900 0.640 7 8/26/04 2:00 0.800 4 5.00 0.800 0.770 5 10/28/04 16:00 0.770 5 3,00 0.667 0.800 4 1/18/06 26:00 0.752 6 2.00 0.500 0.930 2 10/26/06 0:00 0.640 7 1.30 0.231 1.52 1 1/09/08 6:00 0.602 8 1.10 0.091 Computed Peaks 1.32 50.00 0.980 Detention Facility Design Detention Facility Definition Type of Facility Facility Length: Facility Width: Facility Area: Effective Storage Depth: Stage 0 Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Detention Vault 110.00 ft 22.00 ft 2420. sq. ft 20.75 ft 100.00 ft 50215. cu. ft 20.75 ft 12.00 inches 3 Full Head Pipe Orifice 4 Height Diameter Discharge Diameter ft) (in) (CFS) (in) 1 0.00 0.75 0.069 2 12.75 1.50 0.173 4.0 3 18.00 I.00 0.045 4.0 Tap Notch Weir: None Outflow Rating Curve: None Stage/Storage/Discharge Performance Stage Elevation Storage Discharge Percolation ft) (ft) (cu. ft) (ac -ft) (cfs) (cfs) 0.00 100.00 0. 0.000 0.000 0.00 0.01 100.01 24. 0.001 0.001 0.00 0.02 100.02 48. 0.001 0.002 0.00 0.03 100.03 73. 0.002 0.003 0.00 0.04 100.04 97. 0.002 0.003 0.00 0.05 100.05 121. 0.003 0.004 0.00 0.06 100.06 145. 0.003 0.004 0.00 0.47 100.47 1137. 0.026 0.010 0.00 0.88 100.88 2130, 0.049 0.014 0.00 1.28 101.28 3098. 0.071 0.017 0.00 1.69 101.69 4090. 0.094 0.020 0.00 2.10 102.10 5082. 0.117 0.022 0.00 2.50 102.50 6050. 0.139 0.024 0.00 2.91 102.91 7042. 0.162 0.026 0.00 3.32 103.32 8034. 0.184 0.028 0.00 3.72 103.72 9002. 0.207 0.029 0.00 4.13 104.13 9995. 0.229 0.031 0.00 4.54 104.54 10987. 0.252 0.033 0.00 4.94 104.94 11955. 0.274 0.034 0.00 5.35 105.35 12947. 0.297 0.035 0.00 5.76 105.76 13939. 0.320 0.037 0.00 6.17 106.17 14931. 0.343 0.038 0.00 6.57 106.57 15899. 0.365 0.039 0.00 6.98 106.98 16892. 0.388 0.040 0.00 7.39 107.39 17884. 0.411 0.041 0.00 7.79 107.79 18852. 0.433 0.043 0.00 8.20 03.20 19844. 0.456 0.044 0.00 8.61 108.61 20836, 0.478 0.045 0.00 9.01 109.01 21804. 0.501 0.046 0.00 9.42 109.42 22796. 0.523 0.047 0.00 9.83 109.83 23789. 0.546 0.048 0.00 10.23 110.23 24757. 0.568 0.049 0.00 10.64 110.64 25749. 0.591 0.050 0.00 11.05 111.05 26741. 0.614 0.051 0.00 11.45 111.45 27709. 0.636 0.052 0.00 11.$6 111.86 28701. 0.659 0.053 0.00 12.27 112.27 29693. 0.602 0.053 0.00 Stage(StoragelDischarge Performance (continued) Stage ft) Elevation ft) Storage Discharge cu. ft) (ac -ft) (cfs) Percolation cfs) 12.68 112.68 30686_ 0.704 0.054 0.00 12.75 112.75 30855. 0.708 0.054 0.00 12.77 112.77 30903. 0.709 0.055 0.00 12.76 112.78 30928. 0.710 0.056 0.00 12.80 112.80 30976. 0.711 0.059 0.00 12.81 112.81 31000. 0.712 0.062 0.00 12.83 112.83 31049. 0.713 0.066 0.00 12.84 112.84 31073. 0.713 0.071 0.00 12.86 112.86 31121. 0.714 0.075 0.00 12.88 112.88 31170. 0.716 0.076 0.00 13.28 113.28 32138. 0.738 0.100 0.00 13.69 113.69 33130. 0.761 0.116 0.00 14.10 114.10 34122, 0.7B3 0.128 0.00 14.50 114.50 35090. 0.806 0.139 0.00 14.91 114.91 36082. 0.828 0.149 0.00 15.32 115.32 37074. 0.851 0.157 0.00 15.72 115.72 38042, 0.873 0.166 0.00 16.13 116.13 39035. 0.896 0.173 0.00 16.54 116.54 40027. 0.919 0.181 0.00 16.94 116.94 40995. 0.941 0.188 0.00 17.35 117.35 41987. 0.964 0.194 0.00 17.76 117.76 42979. 0.987 0.201 0.00 18.00 118.00 43560. 1.000 0.205 0.00 18.01 118.01 43584. 1.001 0.205 0.00 18.02 118.02 43608. 1.001 0.206 0.00 18.03 118.03 43633. 1.002 0.207 0.00 18.04 118.04 43657. 1.002 0.208 0.00 18.05 118.05 43681. 1.003 0.210 0.00 1B.06 116.06 43705. 1.003 0.212 0.00 18.07 118.07 43729. 1.004 0.213 0.00 18.08 118.06 43754. 1.004 0.214 0.00 18.09 118.09 43778, 1.005 0.214 0.00 18.50 118.50 44770. 1.026 0.231 0.00 18.91 118.91 45762. 1.051 0.244 0.00 19.31 119.31 46730, 1.073 0.255 0.00 19.72 119.72 47722. 1.096 0.264 0.00 20.13 120.13 48715. 1.118 0.274 0.00 20.53 120.53 49683. 1.141 0.283 0.00 20.75 120.75 50215. 1.153 0.287 0.00 Stage/StoragelDischarge Performance at Significant Storm Events Hyd Inflow Outflow Peak Storage Target Calc Stage Elev Cu -Ft) (Ac Ft) 1 1.52 0.37 0.69 20.90 120.90 50584. 1.161 2 0.75 x**** 0.29 20.70 120.70 50104. 1.150 3 0.93 0.19 17.41 117.41 42124. 0.967 4 0.90 0.20 17.83 117.83 43154. 0.991 5 0.80 0.14 14.52 114.52 35130. 0.806 6 0.77 0.09 13.18 113.18 31892. 0.732 7 0.60 0.05 12.50 112.50 30253. 0.695 8 0.64 0.04 7.66 107.66 18546. 0.426 KCRTS Routing Instructions Route Time Series through Facility Inflow Time Series File:dev.tsf outflow Time Series File:RDOut Inflow/Outflow Analysis Peak Inflow Discharge: Peak Outflow Discharge. Peak Reservoir Stage: Peak Reservoir Elev: Peak Reservoir Storage: 1,52 CFS at 6:00 on Jan 0.892 CES at 10:00 on Jan 20.90 Ft 120.90 Ft 50584. Cu -Ft 1.161 Ac -Ft 9 in Year 8 9 in Year 8 Duration Comparison Analysis Duration Comparison Anaylsis Base File: predev.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS Fraction of Time Check of Tolerance ------- Cutoff Base New Change Probability Base New Change 0.064 I 0.95E-02 0.69E-02 27.1 j 0.95E-02 0.064 0.054 15.7 0.081 I 0.63E-02 0.61E-02 4.1 I 0.63E-02 0.081 0.077 4.5 0.098 I 0.50E-02 0.49E-02 1.3 j 0.50E-02 0.098 0.098 0.9 0.116 I 0.37E-02 0.38E-02 4.0 E 0.37E--02 0.116 0.118 1.8 0.133 I 0.29E-02 0.29E-02 1.1 j 0.29E-02 0.133 0.134 0.4 0.151 I 0.22E-02 0.21E-02 5.1 i 0.22E-02 0.151 0.149 1.1 0.168 I 0.15E-02 0.15E-02 2.2 I 0.15E-02 0.168 0.169 0.5 0.185 I 0.10E-02 0.10E-02 3.2 j 0.10E-02 0.185 0.187 0.9 0.203 I 0.62E-03 0.47E-03 23.7 I 0.62E-03 0.203 0.200 1.6 0.220 I 0.34E-03 0.38E-03 9.5 I 0.34E-03 0.220 0.221 0.5 0.238 I 0.21£-03 0.26E-03 30.8 I 0.21E-03 0.238 0.256 7.8 0.255 I 0.16E-03 0.21E-03 30.0 0.16E-03 0.255 0.265 4.1 0.272 I 0.98E-04 0.11E-03 16.7 j 0.98E-04 0.272 0.275 1.1 0.290 I 0.16E-04 0.00E+00 100.0 j 0.16E-04 0.290 0.286 1.3 Maximum positive excursion = 0.019 cfs 7.8%p occurring at 0.243 cfs on the Base Data:predev.tsf and at 0.262 cfs on the New Data:rdout.tsf Maximum negative excursion - 0.019 cfs 25.7%) occurring at 0.073 cfs on the Base Data:predev.tsf and at 0.055 cfs on the New Data:rdout.tsf Duration Comparison Analysis (Continued) Paused - Duration AnaFysis - KCRTS C7 o RDOut.dur c targetdur a mN O N G O OW N O LL U r LUdl f N 17o 00b o i 00 o Q OrmO 10 10 10.3 i0 .2 10 10° Probability Exceedence Wetvault Sizing Calculations Per 2009 King County Stormwater Management Manual Project Name: Wilson Park 2 Facility Description: Wetpool Storage Volume Step 1: Identify required wetpool volume factor (f). f = 3 Per KCSWDM 6.4.1.1 Step 2: Determine rainfall (R) for the mean annual storm. R = 0.47 Per KCSWDM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (Vr) for the developed site. V, = (0.9A. + 0.25A4g + 0.10AK + 0.01 A4) x (R 112) where: A; = Impervious Surface Area = 107,347 s,f. Aig = Till Grass Area = 62,482 s.f. Atf =Till Forest Area = 0 s.f. k = Qutwash Area = 0 s,f. V, = 4,392 c.f. Step 4: Calculate required wetpool volume (Vb). Vb=fxVr Vb = 13,176 c.f. Step 5: Calculate required wetpool depth (DJ. Dmin = V o /(L v x W y/) where: Dm;n = Minimum Calculated Depth Lv = Vault Length = 110 ft. Lw = Vault Width = 22 ft. Dmin = 5.44 ft. Dr = 6 ft. (Min. depth, rounded up to the nearest 0.5 -ft) RAIMA & HOLMBERG IN( TECHNICAL INFORMATION REPORT fo r Wilson Park May 5, 2009 J PE WAS fro e 113322.p I3Tkt`" i I IVAL Baima & Holmberg, Inc. Job No. 2687-001 Prepared For Robert Wilson 720 South 55th Street Renton, WA 98055 city 0f Renton Planning Division OCT 16 t c RECOVER 100 FRONT STREET SOUTH • ISSAQUAH • WASHINGTON • 98027-3817 • (425) 392-0250 • (425) 391-3055 TABLE OF CONTENTS SECTION TITLE 1 PROJECT OVERVIEW 2 CONDITIONS AND REQUIREMENTS SUMMARY 3 OFFSITE ANALYSIS 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6 SPECIAL REPORTS AND STUDIES 7 OTHER PERMITS S ESC ANALYSIS AND DESIGN 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 10 OPERATIONS AND MAINTENANCE MANUAL Street Address 720 South 55`x' Street King County Tax Parcel No. 312305-9125 Project Overview This project involves developing a 2.5 -acre parcel into 13 single-family lots. The site currently is occupied with a single residence, lawn and wooded areas. The site is located about 250' north of South 55th Street, about 150' east of the east terminus of South 53rd Place, on the slope overlooking SR 167, about 1/z mile to the west. The site generally slopes down to the west at an average slope of approximately 20%. Per the SCS soil maps, the site is underlain with Alderwood soil, sandy loam over glacial till. Upstream Tributary Drainage A portion of the parcel to the east of the site drains onto the site. No problems related to this runoff was noted. Level 1 Downstream Drainage Analysis In general, runoff from the site flows west into lots in the adjacent development, Geneva Court (A). The majority of these runoff flows apparently collect in the drain behind an 8'± rockery (B) constructed along the back yards of the west -most lots of said development or in area drains in the back yards, then flow into the storm system in South 53rd Place (C & D). This flow collects in a stormwater pond/bioswale facility located at the intersection of South 53`d Place and Talbot Road South (E), about 750' downstream from the site. This facility outfalls through an 18" pipe to the west side of Talbot Road South into a shallow, poorly defined channel flowing west through the woods (F). The flows pass through a short 12" culvert (H) under a walking path then disappear into thick woods/brush, continuing to flow west to a wooded wetland area (1) beyond 'A mile downstream from the site. This wetland apparently drains to a 10' X 5'± box culvert crossing under SR -167 (Q), about % mile downstrearn from the site. A small area of the south part of the site drains southwest across the south property line of the site into the adjacent parcel to the south (Z). These runoff flows through woods, collecting in a ditches along South 551h Street (K)(about 350' downstream from the site) and/or Talbot Road South (L)( about 800' downstream from the site). Flows into the ditch along South 55` h Street (K) continue west in a 6"-12" rock -lined ditch channel r PORTION OF THE SE -1/4 OF SEC. 31, TWN. 23 N., RNG 5 E_, W[1 CEN OF RENTON, WASHINGTON OIFRiIAP IS 9Ss' FXW 5/B- REEAR t GIP SET ffIM FpOF6 S/9' RE94R t CAP lP1C S. 525: SE I At N PROF. 111E TPS 21170- 0.11' N. t //. 5.f 1/4 W nv 1YR 'CRCI 15' 29337 0.39' N a 953' C OF PROP NR .583 2R 34£ 015' E OF FROF COP I L !A1C. r. su. .m' SS.ea 5x.56- 5e.ao x.ec 165.ao' S.E r/4. S.E r/1, Fm caw ;TRACT r 6 A 1 . 9 7 s OPEJT SPAa/ w 13 8 12 $ '[ 8 Q B I, $ S S,1ST Sq FL 8 s r S10RIF RnPk a Ste2 $ R 9 5•Lt Sq F1 S 5.112 s4 n 5.111 Sq FI $ 5,>16 Sq FL 5.333 Sq fl I N 11 10,494 5'q FI 1 g I rI (!.324 Sq Ft I I) I L.1114' vss o {13,171 Sq Ft R-141 R.5066' ! VV, IS 55 L•10.iJp, t6.33 ,ed E45EL1[1/F r 6.512 SR FI B K .w, Se A7 44 -Tp' ( 1 t11" w s1, I R 1 4,0 1L!3123 03-912 Lee wT131 ISe.eY $ 40=---------- ROAD A Fc :ti. -ems'+ p '°+ 22e.i1- I.51AMES L l 86.00 60.02' 4.1.00' LaarynR.7e.06 dd R0 4 6.356 59 Fl d ?' TR v FOU14 5/9' REBLR t CAP _ - _ ,.'e4,319- to 7 rj g - 124,12' CPS Z2339 05-z' N 8 ^ I Fl C Sq Fc 4 L 34 !] r 6PLTIYSPACC 10.14' E OF PROP COR 4.e3! Sq Fl ' 17T0 9q FL 'rppEx $aA[E S,p3e Sq R 1.321 sq FI 'j - 15' BSBL R $ 4 g OVER1Aq 5 IO Ifi' ' rte- i'F 'C 8 AT S. PROP 113fE 6,2N Sq Fl 6144' } \36.65 60.p6' 7660' }15.60' R I'1 317 O2' I A69 25 3B'M 515 N. IV?'. 3- I I I i SE 1/4. 5.E 1/4 1RACT w 51011" 6RAR.Aa6 TRACT- 065581E iFITUKACCESSFPIPROPERTYT6 I I I' ItPIRI-0IkBD/MNR1R9IeP eT NOA Q 4 I I I eucr Y I I Pn,ICnL 11sR IARC, ls,EeP Ii I I I rl 9LP'iRl-owFm/O.IT.RILa eY I k m a 1RACF 'C Vt I I ' I OD[M SAS - e1A10]•hdNTIMieO I LOT I ;I w RfNrCN SP l 059-85 1 { +I c"K se' II! 50' ROAO AND J + rL" °'E - p P m/ RR 1Rd p I UTUTY EASEA EN T ei xw II 4 i REC NO 200.90327002018 i I 94mit so gifg a N hEA "r I 22t AMS RENO ?1102050 LOT 2 I I i RLTf1rNI SP l 059-93 I I a l I I I i I 1 I 1 ALE Ir 30' I , u I I 11. r• v^p` r 1` QT TIP I [ r COGS 169 sTi X11119.71' '•+''- I y/ Y o \ rt. " b RI z731,a3' S 55TH ST. a" I F , 1111 r T NW X'b1r 2616.43PE153 roLra CI?MCREJI . 8705 O iL. SEC. cw Site Plan V=80 a' Vicinity "~ U rt atd i - pgC 2 1 Py .. i ® . ° 451 Cl Wo Jr 9k =-= i o IAgC I m . . A 8g I I, TTu 4 j I ag6 f to 1 _ Inc a a So j Ago , 7 a me • a M 17 Py Wbb .r r • ; : s ; WO ` M 194 1 ' n ` •1 • 3 AmB e AgC • ++ .. 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Os AkF ; ASC\ _•; Qs C}s LP 8O a OW AkF + 1 AgCRe I r CS uOP If our I r • Ag Ur SCS Soil Ma I ASD • { • Pu Sm OF [ Ur y yW , EMUS q E\ Ki• County Department of Development a- 'Environmental Services TECI CAL INFORMATION REPO (TIR) WORKSHEET Parti °PROJEGTOWNER=REVD PROJECT ENGINEER Project Owner Address wn ;,.)un -4 S 5nA- e r apt Project e, 5nglneer LKA B04 Company I Address/Phone _j[.Z gOt-T `PT- Subdivison Short Subdivision Grading Commercial Other Part 2 _ PROJECT LOCATION AND DESCRIPTION Project Name WiLLU10 RrIfZ - Location Township 2.3 Range -S Jr .....Sectton 31 Part 4 }THER REITIEWS, [ND_PEI31NiTS F := DFW HPA Shoreline Management COE 404 Rockery DOE Dam Safety Structural Vaults FEMA Floodplain Other GO Wetlands Pait5 SITE C N MCINiTYaND DRAINAGE B3 SI[ 4f Community Drainage Basin Part 6 'SITE CHARAGTERISTFGS River Floodplain Wetlands Stream Seeps/Springs Critical Stream Reach High Groundwater Table Depressions/Swales Groundwater Recharge Lake Other Steep Slopes Part7= .SOI LS Soil Type Slopes Erosion Potential A OfttAlao D KAOE fl r Additional Sheets Attached Erosive Velcoties Part'S., DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT Ch. 4 — Downstream Analysis— t a U& A — 1jC9 gp r, We ?s Additional Sheets Attached MINIMUM ESC REQUIREMENTS I DURING CONSTRUCTION Sedimentation Facilities v Stabilized Construction Entrance Perimeter Runoff Control Clearing and Graing Restrictions I vCover Practices f I/Construction Sequence Other MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION k6tabilize Exposed Surface . Remove and Restore Temporary ESC Facilities CEean and Remove All Silt and Debris Ensure Operation of Permanent Facilities Flag Limits of SAO and open space preservation areas Other Part 10-:SURFAGL. 1ATER 8"YSTEM Grass Lined Tank Infiltration Channel Vault Depression Pipe System Energy Dissapator Flow Dispersal Open Channel Wetland Waiver Dry Pond Stream Regional Wet Pond Detention Method of Analysis Compensation/Mitigati on of Eliminated Site Storage Brief Description of System Operation 51TFF,-- D1101fuez 122 60"3Q --Ry IA- LIT1't G Facility Related Site Limitations Reference Facility Limitation Fait 1 .,.STFiIJCTFiA:AN/ALYS[S', mast in Place Vault Retaining Wall bckery a 4' High Structural on Steep Slope Other PartAi2:. E1 SESTWCTS ° 3. Drainage Easement Access Easement Native Growth Protection Easement Tract Other Park 13.4'SIGNATU,RE 01= PRDFESSiQiVA ENGINEER I or a civil engineer under my supervision my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate.