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HomeMy WebLinkAboutSEPA E2000-032 - CHRISTOPHER OLIVIER - 7 LOT SHORT PLAT ADJACENT TO MACADAM ROANALEWAJEK SHORT PLAT SHORT PLAT TO 7 LOTS 13900 48T" AVE. SO. E2000 -032 FROM : Panasonic FAX SYSTEM PHONE NO. : Sep. 16 2002 02:36AM P2 DEVELOPMENT BROCHURE 1 -2 GEOTECHNICAL REPORT GUIDELINES PROVIDE NOTARIZED RECORDED COPY GEOTECHNICAL AFFtDAV.IT FROM OWNER ., , Legal Description: • ;' eimpr 471 , or, one-Warn. Parcel Numbers /5x30 4/907x- City of Tukwila Permit Numbers 7 O - 0,3Q Ct/fId.. LLcoo �l Geotechnical Report titled: A:LZ s ter. Prepared by : �olcier Orr pssc�cc s Dated: understand and accept the risk of developing in an area with potential. unstable soils. 0./.‘ 0 2- StAteorticied a.nci Sworn -10 - -4-L mss 1 1,2+1. cL -j o \r‘ reSictArv6 .k ` gr-""°` Gorr. s5: g., *.,uzs a bolos Brochure 1-2 6 FROM : Panasonic FAX SYSTEM PHONE NO. : Sep. 16 2002 02:36AM P1 DEVELOPMENT BROCHURE 1-2 GEOTECHNICAL REPORT GUIDELINES PROVIDE NOTARIZED RECORDED COPY GEOTECHNICAL COVENANT FROM THE OWNER Legal Description: tr).ehr--v pkcc,/ on fi\as_ 2octc3c 3, 7 Lcts , j(?C Orttcl‘ackt/;:h Parcel Numbers /5,04/49.07c2- City of Tukwila Permit Numbers .7.00.0—(-93 arta L_C0' 0-4":1771 • , • • • • Gectechnical Report title : Prepared by: Gaciadact_cdzak5 Dated: This site is fn an area of potential geologic instability, as determined bY the City of Tukvvila. The risks associated with development of this site are... ". Conditions or prohibitions on development of this site are: Design features, which require maintenance or modification to address anticipated soil changes, are: , waive any claims 1, my successors or assigns may have a•-1, Lt the City for any loss or damage to people or property, either on • off the site, resulting from soil movement arising out of the issuance of any permit(s) authorizing development on the site. brythure 1-2 7 ar,d, 19e_C-bi\Q- fl Nk 4LA_s aooa elscox,i YVJ.QJ v. cu-18, *L9. c-C Was Lvq-c cese-a■6-x-r Ot.4- L6eLV-vr-Lek CAYYV/NA5Th (?t•r•°S: \% DEVELOPMENT BROCHURE 1 -2 GEOTECHNICAL REPORT GUIDELINES PROVIDE NOTARIZED RECORDED COPY GEOTECHNICAL AFFIDAVIT" FROM GEOTECHNICAL ENGINEER Legal Description: Show 7 1„6\s Parcel Numbers ■ on (tic dam 1ZoG c� S• KPle0,&trrn T2 s City of Tukwila Permit Numbers L 2600 In m judgement, •on review of the,+n4ruc�lo plans and specifications for — d -Z , . 0c 0 th.e• plans and specifications co form to the geotechnic recom endations..I' made in the geotechnical rep rt, titled SJ €.2( Q O L1 , ('(� (tea and dated 9p- ©� . 1 In my judgement, the risk to the proposed development from soil instability will be minimal and the proposed development will not increase the potential for soil movement, subject to the conditions set forth in my report. Brochure 1 -2 I) 0-11 .[Aruci\ucet 0-\oLati) mos bx s''-e Ski8Nr-\p� Z1 A cb411n ►e� QQo� eChni�a.[ -0°� 1T1 2e2 6 mt,(4-1\ mon\kvr Cry Ltia%i Cf�t1/lit»r, I(d) AI''ilc.r/k1 City of Tukwila Steven M. Mullet, Mayor Department of Community Development Steve Lancaster, Director NOTICE OF DECISION June 13, 2002 Christopher Olivier 3805 S. 150 Street Tukwila, WA 98188 RE: L2000 -077 Dear Mr. Olivier, The Short Subdivision Committee has completed review of your short plat application, and determined that it complies with all applicable City code requirements. The City SEPA Responsible Official has previously determined that the project does not create a probable significant environmental impact if specific mitigation conditions are imposed on the project and issued a Mitigated Determination of Non - Significance (MDNS) requiring compliance with those mitigation conditions: 1. The recommendations contained in the Geotechnical Design Report by Golder Associates dated March 21, 2002 shall be followed for all site work and house construction. 2. The installation of the auger cast piles for the house foundations shall be monitored by an experienced geotechnical field engineer, preferably from the Golder firm. That engineer must provide a report to the City detailing his/her observations and opinion of the adequacy of the piles prior to the pouring of the house slabs. This letter serves as the Notice of Decision per TMC 18.104.170. Based on the latest project submittal, preliminary approval is granted subject to the conditions stated below. There are three basic steps in the short plat approval process: 1. Preliminary Approval This letter constitutes your preliminary approval. The application was reviewed by the Tukwila Short Subdivision Committee and approved with conditions. The conditions imposed are to ensure the short plat is consistent with the Criteria for Preliminary Approval listed at TMC 17.12.020 C in the Tukwila Subdivision Code. Page 1 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone: 206 - 431 -3670 • Fax: 206 - 431 -3665 • • PRELIMINARY APPROVAL CONDITIONS Utilities a. The storm drainage system shown on your drawing of 1/29/02 shall be installed prior to final plat approval. The storm drainage design for the lots shall meet the requirements of the 1998 King County Surface Water Design Manual and the recommendations of the geotechnical report. The design shall include all added impervious surfaces. b. Pursuant to the Tukwila "underground ordinance ", all utilities shall be placed underground. c. The water line in Macadam Road shall be upgraded to an 8 inch main per previous agreement with Water District 125. As -built plans shall be provided to the Public Works Department. Access d. Frontal improvements including pavement widening, curb, gutter, sidewalk, storm drainage and street lighting must be installed along the length of the lots. e. A sight distance study for the driveways shall be submitted to the Public Works Department for review and approval. Fire Protection f. A fire hydrant capable of a 1000 gallon per minute flow must be installed per the approved plan and agreement with Water District 125. General g. You will need to obtain all required permits prior to beginning any construction. For water and sewer permits, contact the individual provider District. For land altering, frontal improvements and storm drainage contact Tukwila Public Works at (206) 433 -0179. h. Install all required site improvements, including those proposed in the short plat application and those identified above as conditions of approval. i. Submit a set of recording documents in either legal or record of survey format that meet the King County Recorder's requirements and contain the following items: 1. A survey map in NAVD 1988, NAD 83/91 that is consistent with all of the conditions of approval. The surveyor's original signature must be on the face of the plat. Short Plat LO1 -019 Page 2 City offukwila Department of Community Development / 6300 Southcenter BL, Suite 100 / Tukwila, WA 98188 / (206) 431 -3670 MITIGATED DETERMINATION OF NON - SIGNIFICANCE (MDNS) File Number: Applied: Issue Date: Status: E2000 -032 11/28/2000 05/20/2002 ISSUED Proponent: CHRISTOPHER OLIVIER Lead Agency: City of Tukwila Description of Proposal: 7 LOT SHORT PLAT ADJACENT TO MACADAM ROAD SOUTH Location of Proposal: Address: 13900 48 AV S TUKW Parcel Number: 1523049072 SectionfTownsh i p /Range: The City has determined that the proposal 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). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. The conditions for this SEPA Determination are amended at the end of this document. This DNS is issued under WAC 197 -11- 340(2). The conditions are attached. Comments must be submitted by 3..).N2 y 2402— . The lead agency will not act on this proposal for 14 days from the date below. For a copy of the appeal procedures, contact the the City of Tukwila Department of Community Development. Steve Lancaster, Responsible Official City of Tukwila 6300 Southcenter Blvd Tukwila, WA 98188 (206)431 -3670 AAA-'t 2,0 'Zcc o Z Date Any appeal shall be linked to a specific governmental action. The State Environmental Policy Act is not intended to create a cause of action unrelated to a specific governmental action. Appeals of environmental determinations shall be commenced within the time period to appeal the governmental action that is subject to environmental review. (RCW 43.21C.075) SEPA Determination Conditions: 1: The recommendations contained in the Geotechnical Design Report by Golder Associates dated March 21, 2002 shall be followed for all site work and house construction. 2: The installation of the auger cast piles for the house foundations shall be monitored by an experienced geotechnical field engineer, preferably from the Golder firm. That engineer must provide a report to the City detailing his /her observations and opinion of the adequacy of the piles prior to the pouring of the house slabs. doc: Miscperm E2000 -032 Printed: 05 -17 -2002 MEMORANDUM TO: Steve Lancaster, DCD Director 0 FROM: Nora Gierloff, Planning Supervisor • • RE: SEPA — Olivier 7 lot short plat DATE: May 17, 2002 Project File No. E2000 -032 Project Description: The project involves short platting a 1.72 acre parcel with Class 2 and 3 slopes, a Type 3 watercourse and a Type 3 wetland into 7 single family lots. Agencies With Jurisdiction: Washington State Department of Ecology Comments to SEPA Checklist: One comment letter on the project was received objecting to the project on the grounds that the site has historically been filled with a variety of materials including building debris. The applicant has provided a geotechnical study addressing the fill issue that has been peer reviewed by Shannon & Wilson. Summary of Primary Impacts: 1. Earth — Grading will be required as shown on the attached plan to construct driveways to the lots, install frontage improvements and install the storm drainage system. Additional grading will occur during house construction. The geotechnical report by Golder Associates dated March 21, 2002 makes recommendations for the house foundations, distances the houses and utilities should be set back from the slope, construction practices and drainage design. The erosion control standards in the King County Surface Water Design Manual must be met. 2. Air - There will be exhaust emissions from construction equipment during the project. Dust control measures in compliance with the Puget Sound Clean Air Agency will be used as needed. The project's air emissions when complete will be those typical of single family development. • • 3. Water —The surface water from the developed portion of the site will be collected and detained in a pipe before being metered into the watercourse along the eastern edge of the site. The only construction activity that will occur within the wetland/watercourse buffer is the storm drainage outfall. An erosion control plan will be required as part of the land altering and building permits. 4. Plants — Currently the site contains alders, shrubs, grass and blackberries. No significant trees will be removed due to house or utility construction. No vegetation will be cleared within the wetland or watercourse buffers. 5. Animals — No threatened or endangered species have been observed on site. The wetland/watercourse buffer is expected to preserve the existing low value riparian habitat. 6. Energy and Natural Resources - The project will require energy for construction equipment and for vehicles coming to the site. Once completed energy use will be typical of that for single family development. 7. Environmental Health - No environmental health hazards are anticipated. Construction equipment operation will need to comply with Tukwila's noise ordinance. 8. Land and Shoreline Use - The project is consistent with the existing single family residential zoning and comprehensive plan designation for the site. 9. Housing —Seven new houses will be constructed on the currently vacant site. 10. Aesthetics - The project is not subject to BAR requirements. 11. Light and Glare — The streetlights will have to meet City of Tukwila standards for height and spacing. 12. Recreation - The proposal will not affect recreational facilities. 13. Historical and Cultural Preservation - The site is not known to have any historical or cultural significance. 14. Transportation — The proposal will add the number of trips typical of single family development. No traffic mitigation is required. Half street improvements including additional paving, curb, gutter, streetlights and sidewalks will be constructed along Macadam Road. A sight distance study for the driveways will be required prior to preliminary approval of the short plat. 15. Public Services - The project will result in an incremental increase in demand on public services. • • 16. Utilities - The project will result in an incremental increase in utility usage. Utilities will be undergrounded along Macadam and to each house. Recommended Threshold Determination: Mitigated Determination of non - significance. Mitigation Conditions: 1. The recommendations contained in the Geotechnical Design Report by Golder Associates dated March 21, 2002 shall be followed for all site work and house construction. 2. The installation of the auger cast piles for the house foundations shall be monitored by an experienced geotechnical field engineer, preferably from the Golder firm. That engineer must provide a report to the City detailing his/her observations and opinion of the adequacy of the piles prior to the pouring of the house slabs. OM 1H SHANNON F�WILSON, INC. ® GEOTECHNICAL AND ENVIRONMENTAL CONSULTANTS April 25, 2002 Mr. Dave McPherson, Associate Engineer City of Tukwila Department of Public Works 6300 Southcenter Boulevard Tukwila, WA 98188 -2544 SEATTLE RICHLAND PORTLAND FAIRBANKS ANCHORAGE DENVER SAINT LOUIS RECEIVED APR 2 6 2002 TUKWILA PUBLIC WORKS RE: GEOTECHNICAL PEER REVIEW, NALEWAJEK 7 -LOT SHORT PLAT, 13900 MACADAM ROAD, TUKWILA, WASHINGTON Dear Mr. McPherson: This letter presents the results of our peer review of a geotechnical engineering report for the proposed Nalewajek Short Plat project. The project site consists of seven lots located in the 13900 block of Macadam Road, Tukwila, Washington. The purpose of our work is to offer an opinion as to the adequacy of the geotechnical engineering report submitted with the permit application. The geotechnical report for this project was prepared by Golder Associates, Inc., dated March 21, 2002. The report presents the results of eight test pit explorations, three soil borings, and geotechnical recommendations for site development. The test pit explorations extended to depths of 10 to 15 feet and encountered fill materials. The soil borings extended deeper than the test pits and encountered stiff or dense native soils underlying the fill at depths of 22 and 28.5 feet below ground surface. The report provided descriptions of the site geology, site development history, and subsurface soil and groundwater conditions. It provided opinions and recommendations regarding site development, foundations and earth pressures, slope stability, liquefaction hazards, buffers and setbacks, and other typical geotechnical design issues. Based on our review of the Golder Associates report and our previous observations of the site, we generally concur with the opinions and recommendations provided for site development and building foundations. It is our opinion that the geotechnical report prepared for this project meets the generally accepted standards of practice in this area and meets the standards of Tukwila Municipal Code 18.45.080E. 400 NORTH 34TH STREET • SUITE 100 P.O. BOX 300303 SEATTLE, WASHINGTON 98103 206.632.8020 FAX 206.695.6777 TDD: 1.800.833.6388 21 -1- 09472 -002 • . Mr. Dave McPherson City of Tukwila Dept. of Public Works April 25, 2002 Page 2 SHANNON iWILSON.INC. We appreciate the opportunity to be of service. If you have any questions, I am available at (206) 695 -6875. Sincerely, SHANNON & WILSON, INC. W i o� �v�sy,ti L ;l .z ?/, 30308 VOA ONAL ¶ 44 EXPIRES 4/21/ 041 Martin W. Page, P.E. Senior Principal Engineer MWP:TMG /mwp 21 -1- 09472- 002 -L1 /WP /LKD 21 -1- 09472 -002 • • ®III SHANNON ILON, INC. ENVIRONMENTAL CONSULTANTS April 25, 2002 Mr. Dave McPherson, Associate Engineer City of Tukwila Department of Public Works 6300 Southcenter Boulevard Tukwila, WA 98188 -2544 SEATTLE RICHLAND PORTLAND FAIRBANKS ANCHORAGE DENVER SAINT LOUIS RECEIVED APR 2 6 2002 TUKWILA PUBLIC WORKS RE: GEOTECHNICAL PEER REVIEW, NALEWAJEK 7 -LOT SHORT PLAT, 13900 MACADAM ROAD, TUKWILA, WASHINGTON Dear Mr. McPherson: This letter presents the results of our peer review of a geotechnical engineering report for the proposed Nalewajek Short Plat project. The project site consists of seven lots located in the 13900 block of Macadam Road, Tukwila, Washington. The purpose of our work is to offer an opinion as to the adequacy of the geotechnical engineering report submitted with the permit application. The geotechnical report for this project was prepared by Golder Associates, Inc., dated March 21, 2002. The report presents the results of eight test pit explorations, three soil borings, and geotechnical recommendations for site development. The test pit explorations extended to depths of 10 to 15 feet and encountered fill materials. The soil borings extended deeper than the test pits and encountered stiff or dense native soils underlying the fill at depths of 22 and 28.5 feet below ground surface. The report provided descriptions of the site geology, site development history, and subsurface soil and groundwater conditions. It provided opinions and recommendations regarding site development, foundations and earth pressures, slope stability, liquefaction hazards, buffers and setbacks, and other typical geotechnical design issues. Based on our review of the Golder Associates report and our previous observations of the site, we generally concur with the opinions and recommendations provided for site development and building foundations. It is our opinion that the geotechnical report prepared for this project meets the generally accepted standards of practice in this area and meets the standards of Tukwila Municipal Code 18.45.080E. 400 NORTH 34TH STREET • SUITE 100 P.O. BOX 300303 SEATTLE, WASHINGTON 98103 206.632.8020 FAX 206.695.6777 TDD: 1.800.833.6388 21 -1- 09472 -002 • • Mr. Dave McPherson City of Tukwila Dept. of Public Works April 25, 2002 Page 2 SHANNON 61/VILSON. INC. We appreciate the opportunity to be of service. If you have any questions, I am available at (206) 695 -6875. Sincerely, SHANNON & WILSON, INC. EXPIRES 4/21/ o 4' Martin W. Page, P.E. Senior Principal Engineer MWP:TMG /mwp 21 -1- 09472 - 002 -L1 /WP /LKD < 21 -1- 09472 -002 Golder Associates Inc. 18300 NE Union Hill Road, Suite 200 Redmond, WA 98052 -3333 Telephone (425) 883 -0777 Fax (425) 882 -5498 REPORT ON GEOTECHNICAL DESIGN REPORT MACADAM ROAD SOUTH RESIDENTIAL PLAT TUKWILA, WASHINGTON Prepared for: John Nalewajek Submitted by: Golder A Redmon soci Was tes Inc. ngton Frank S. Mocker Ro"' L. Plum, P.E. Project Geologist March 21, 2002 Principal RECEIVED MAR 2 5 2002 TUKWi LA PUBLIC WORKS Golder Associates v,RT pl • of wAsi 41tf l• r, ,t 1 524 • �fC1.577.7-0 MEMEIVARYma As 'Z, b'. OFFICES ACROSS ASIA, AUSTRALASIA, EUROPE, NORTH AMERICA, SOUTH AMERICA March 21, 2002 TABLE OF CONTENTS • 1. INTRODUCTION 2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT 2 2.1 Proposed Development 2 2.2 Site Description 2 2.3 Aerial Photograph Review 3 • 023 -1014- 100.100 Page No. 1 3. FIELD EXPLORATION 3.1 Subsurface Explorations 4 3.2 Laboratory Testing 4 4. SUBSURFACE CONDITIONS 5 4.1 Soil 5 5 4.2 Surface Water and Groundwater 4 5. ENGINEERING EVALUATIONS 5.1 Liquefaction And Lateral Spreading Assessment 7 5.2 Stability 7 5.3 Foundation and Development of Stable Slopes 8 7 6. DESIGN RECOMMENDATIONS 6.1 Foundation Recommendations 9 6.2 Slab On Grade 10 6.3 Foundation Drainage 10 6.4 Slope Setbacks and Regrading 10 7. CONSTRUCTION CONSIDERATIONS 12 7.1 Subgrade Preparation 12 7.2 Fill 12 7.3 Auger Cast Piles 12 7.4 Construction Monitoring 13 9 8. USE OF REPORT Golder Associates 14 March 21, 2002 1 411 023 - 1014 - 100.100 1. INTRODUCTION Golder Associates Inc. (Golder) is pleased to present the results of our geotechnical design report for the Macadam Road South Residential Plat. The site is located between Interstate 5 and Macadam Road in Tukwila, Washington as shown on Figure 1. The scope of work for this project was presented in our proposal to you dated February 12, 2002. We proceeded with our study based on your signed authorization dated February 15, 2002. We had completed a previous report for the site titled Preliminary Geotechnical Study, Macadam Road South Residential Plat, Tukwila, Washington dated January 15, 2002. The earlier report recommended that additional explorations and engineering be completed for final design and construction. Thus the main purpose of the work presented in this report was to complete the additional work and develop recommendations suitable for permitting, design and construction of the project. The scope of this report included additional borings, additional test pits, laboratory testing, engineering analyses and development of geotechnical design and construction criteria. Our work addresses the specific site development concept depicted on the proposed Plat Plan by Jaeger Engineering dated 11/3/01 (note: we understand that the large- diameter detention pipe shown on the 11/3/01 plan has been relocated to the west away from the slope). We have concluded that the project can be developed as planned but it will be required that the buildings be pile supported due to the thickness and poor quality of the fills underlying the site. We also recommend that the structures are off set from the top of the fill slope due to the risk of shallow sloughing failures of the slopes. Alternatively, the piles could be designed to resist the lateral forces developed by these shallow slides. Golder Associates March 21, 2002 • 2 • 023 - 1014 - 100.100 2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT 2.1 Proposed Development Based on the Jaeger Engineering plan, the site will be divided into seven lots fronting along Macadam Road as shown on Figure 2. We understand that three of the houses (Lots 1, 6, and 7) located on sloping ground will include a daylight basement. Some limited filling and cutting will be required to construct the houses and grade the final lots. We understand that there will be a stormwater- detention pipe some six feet in diameter and about 300 feet long. It has been relocated from its original design location near the crest of the fill slope to a new location in front of the houses. At the time we prepared this report, the exact location and design of the houses had not been determined. However, we have assumed that they will be conventional one- to two - story wood -frame structures, some with a daylight basement. In addition, we had not reviewed the revised plans showing the new detention -pipe location. 2.2 Site Description The site consists of approximately 1-3/4 acres, which is roughly rectangular in shape and is located between Interstate 5 (I -5) and Macadam Road in Tukwila, Washington as shown on Figure 1. Site elevation ranges from approximately 195 feet at the level portion of the property adjacent to Macadam Road to about 164 feet in the northeast corner of the property adjacent to I -5. The site has a relatively level portion adjacent to Macadam Road. The topography then slopes down to the east towards I -5 at about 3H:1V to 4H:1V to a small swale located adjacent to I -5. Currently the level portion of the site is mainly open with tall grasses and small brush. The sloping portion is covered with brush and small trees. We reviewed plans developed by Arnett and Associates dated 1990 showing general site layout, lot subdivisions, a proposed subsurface cut -off drain, and a proposed surface drainage system. We understand that the sub drain and surface drainage system were installed. We observed some of the surface drainage features shown on the Arnett and Associates plans during our recent investigation. These include a catch basin and a manhole located at the top of the existing fill slope in Lot 2. We understand that the site has been filled at least three times over the years. This appears to include fill placed prior to 1986, fill placed between 1986 and 1990, and some re- grading of the fill after 1990. Our aerial photographic review (Section 2.2.1) generally supports this history. Based on this information supplanted with some older topographic plans and sections, we were able to estimate the elevation of the original ground and depth of current fill. We observed evidence of a shallow scarp along the east - facing fill slope as shown on Figure 2. The scarp averages about 1.5 feet in height and extends north -south across the full length of the fill slope. Anecdotal information indicated that a slide may have occurred within the fill in the late 1980's requiring excavation of material from the drainage swale Golder Associates March 21, 2002 • 3 • 023 - 1014 - 100.100 adjacent to I -5. In addition, it appears that the rion 2.3) may have been placed back onto the fill slope. Our aerial photographic review ( ) g enerally supports this history. 2.3 Aerial Photograph Review As part of our study, we performed a review of aerial photographs from 1936 to 2000. The aerial photographs were available at Walker and Associates located in Tukwila, Washington. A list of the aerial photos we reviewed, along with a summary of our observations, is presented in the table below. 1 Date of Photo Approximate Scale Comments /Observations 1936 Apri110,1956 Black- and -white photos. Pre - highway I -5 and SR -599. Pre -fill. Macadam Road present. Cultivated orchards up slope of road. Tall trees observed on old slope below road. No evidence of disturbed ground. Black- and -white photos. Same observations as 1936 except no orchards observed up slope of Macadam Road. Slope above road looks to be recently cleared. May 4, 1980 1 inch = 1000 feet 1 inch = 1000 feet 1 inch = 1000 feet July 10, 1990 1 inch = 1000 feet October 7, 2000 1 inch = 2000 feet Black- and -white photos. Highways I -5 and SR -599 exist. Pre -fill. Turnout adjacent to Macadam Road in northwest ,_corner of property. Tall trees on slope below road look straight. Remainder of site to east is low -lying with low vegetative growth (grasses ?). Drainage swale and fence line present adjacent to I- 5. No evidence of disturbed ground in or around site. Color photos. Fill has been recently placed on portions of the site. Very limited vegetative cover observed on the fill (older fill surface only). Possible scarps observed in the vicinity of Lots 3, 4, and 5 near crest in east - facing fill slope (Figure 3) These possible scarps are located in the area of the scarps observed on the site during this investigation. Color photos. Site is well vegetated with light brown grasses on flat portion of site and dark green (young trees) on fill slopes. No evidence of disturbed ground. Ground surface obscured by vegetative cover. Golder Associates March 21, 2002 3. FIELD EXPLORATION 3.1 Subsurface Explorations 4 023 - 1014 - 100.100 The subsurface explorations included eight test pits and three borings. The locations are shown on Figure 2 and the logs are included in Appendix A. Golder excavated 6 test pits (TP -1 to TP -6) in 1999 located in the flat portion of the property adjacent to Macadam Road. These test pits were surface (bgs). excavated to depths of between 10 and 15 feet below the existing ground The most recent geotechnical subsurface exploration program was performed between February 25 and February 27, 2002. The work consisted of two additional test pits (TP -7 and TP -8) excavated adjacent to I -5 at the toe of the existing fill slope. In addition, we completed three borings located near the crest of the existing fill slope in Lots 1, 4, and 7. The location of the test pits and borings are shown split-spoon sampler B(F (Figure 2). were Samples were obtained from the borings using a SPT taken from the test pits. The borings were performed by Boretec Drilling out of Spokane, Washington using a custom -built MM 45 drill rig to depths of between 36.5 and 40 feet bgs. The test pits were excavated to depths of 120 excavator. At test pit TP -8, the excavator � s� k in soft, saturated soils. This required another excavator to aid in extracting the excavator. The test pits and borings were located in the field based on hand measurements and pacing from existing site features and should be considered approximate. The field explorations were performed under the full -time observation of a representative of our firm who recorded soils information including depths, stratigraphy, soil engineering characteristics and groundwater occurrence. of Borehole forms (See Appendix A) recorded on Golder Field Test Pit Log forms and Record Disturbed but representative samples were collected and returned to our laboratory for further examination and testing. The exploration test pits were backfilled immediately after the subsurface conditions were recorded. Some settlement of the backfill in the test pits should be expected. 3.2 Laboratory Testing Laboratory testing consisted of washed sieves and minus #200 washed sieves. The results are included in Appendix B. Golder Associates March 21, 2002 • 5 023 - 1014 - 100.100 4. SUBSURFACE CONDITIONS 4.1 Soil Waldron (1962)' mapped the geology in the area of the site as undifferentiated pre - Vashon drift overlain by Vashon -aged ground moraine deposits (till). These deposits are generally hard and/or very dense as they have been deposited in front of or beneath the advancing glacier and have been overridden by the full weight of the glacier. Recessional outwash and lacustrine silt, clay, and peat are mapped by Waldron on the east side of the site in the area of I -5. These units are generally loose to compact and/or soft to very stiff as they were deposited during the recession of the Vashon glacier and were generally not overridden by the full weight of the glacier. Based on the soil conditions observed in our test pits and borings, the site is mantled by compact to very loose fill underlain by recessional lacustrine deposits. These units are then underlain by dense to very dense till and stiff glaciolacustrine deposits. Soil units encountered during our geotechnical exploration program are summarized in more detail below: • Fill — Fill was encountered in all the test pits and borings. The depth of the fill ranges from about 12 feet bgs adjacent to Macadam Road, to about 27 feet bgs at the crest of the fill slope in Lot 4. The fill encountered was variable but can be split into two units. • Upper Fill: The upper 5 to 15 feet beneath the flat portion of the site consisted primarily of compact to dense fine to coarse sand with varying amounts of silt and gravel and minor organics. Some of the 1999 test pits encountered building debris in the fill including bricks, chunks of asphalt, pieces of concrete, pipe, etc. This upper compact to dense fill layer may represent the newer fill placed after 1983 as discussed in Section 2.3. • Lower Fill: Underlying the upper fill, the explorations encountered very soft and very loose finer - grained fill. This unit was also observed in the two test pits excavated at the toe of the fill slope adjacent to I -5 and in the borings. The lower very loose and very soft fill unit consists of primarily silt ranging to silty clay with a trace to little sand and gravel and a little to some fine- grained organics. The lower fill unit can vary to fine to coarse sand with some clayey silt and a trace of organics. The more organic -rich fill was observed in the areas of Lot 1 and the toe of the fill slope adjacent to I -5. • RecessionalLacustrine Deposit — This unit was observed in boring GB -1 located in Lot 4 between about 26.5 feet and 28.5 feet bgs, and in the test pits located at the base of the fill slope in Lots 2 and 4. The unit consists of interbedded loose to compact, silt, fine to medium sand, and firm to very stiff, dayey silt. The unit contains a trace of gravel throughout and is commonly iron oxide stained. Pocket penetrometer readings in this unit range from about 1.5 to 3.5 tsf (tons per square foot). ' Waldron, Howard H., 1962. Geology of the Des Moines Quadrangle, Washington: U. S. Geological Survey Map GQ -159. Golder Associates ■ 4110 6 023 - 1014 - 100.100 March 21, 2002 • Till - We encountered this unit underlying the fill in all the borings at depths of between 22 and 28.5 feet bgs. r coarse Th coarse nonstratified, silty, fine to sand with a little fine to coarse rounded gravel. The till can vary to clayey silt and is iron oxide stained. • Glaciolacustrine Deposit — This unit was encountered underlying the till in boring GB -3. This unit consists of very stiff, massive to faintly laminated, clay ranging to silty clay with thin interbeds of fine to medium sand. The unit contains ice - loading features such as jointing and contorted bedding. 4.2 Surface Water and Groundwater Surface water was observed in the drainage swale at the base of the fill slope bordering the eastern property line. No surface water was observed on the fill slope or in the swale adjacent to Macadam Road. No evidence of seepage was observed on the existing fill slope. Groundwater seepage was observed in all but one of our test pits and likely represents the groundwater levels at that time. We measured the groundwater level in GB -1 at the time of drilling. In the other holes, groundwater did not stabilize in the hole during drilling. In these boreholes we estimated e approximate depth and where we first encountered soils that appeare d saturated. Th elevation of groundwater occurrence in our test pits and borings is summarized below. Test Pit/Borehole Number Date of Groundwater Observation Approximate Ground Surface Elevation (feet MSL) TP -2 TP -3 TP-4 TP -5 TP -6 TP -7 TP -8 4/8/99 4/8/99 4/8/99 4/8/99 4/8/99 2/28/02 2/28/02 GB -1 GB -2 2/25/02 2/25/02 198 197 196 195 194 166 174 195 GB -3 2/26/02 195 193 Approximate Depth to Groundwater (feet bgs) 9.5 13 13 8 7 2 4.5 12.5 10 10 Approximate Groundwater Elevation (feet MSL) 188.5 184 183 187 187 164 169.5 182.5 185 183 Note: The groundwater depths and elevations shown above are approximate and are for the time and date shown. The depth to groundwater in the borings is interpreted based on observed wet soil conditions in the samples. Based on this information, the groundwater levels were about 10 feet below the ground surface on the western level portion of the site becoming shallower near the toe of the fill slope. Groundwater levels should be te would to during late of year. The groundwater levels at this g enerally be the highest winter and spring depending on precipitation. Golder Associates March 21, 2002 • 7 • 023 - 1014 - 100.100 5. ENGINEERING EVALUATIONS 5.1 Liquefaction And Lateral Spreading Assessment Loose granular soils below the water table can be susceptible to liquefaction and lateral spreading during a major seismic event. Accordingly, we completed an evaluation of these risks for the proposed site development. These risks can be assessed based on the SPT blow counts and the composition of the soils. Typically, fine- grained soils and/or soils with SPT values in excess of about 10 have a low liquefaction risk. Based on the exploration, loose /soft soils below the water table occurred the lower fill unit as described in Section 4.1. This unit is primarily fine- grained consisting of silt ranging to silty clay with a trace to little sand and gravel and a little to some fine- grained organics. In some areas it varies to fine to coarse sand with some clayey silt and a trace of organics. In general organic and plastic . soils are considered to have a low susceptibility to liquefaction. The more granular soils still had relatively high percentage of silt. We completed a liquefaction evaluation of these soils using the general Seed procedures, which takes into account the high silt content. The results indicated that these materials generally have a low liquefaction potential except for a few localized areas of cleaner loose sands within the lower fills. We considered the risk of lateral spreading or slope failure caused by liquefaction. Conservatively assuming a continuous zone of liquefiable soils in the slope area, the calculations indicate a low risk of seismically induced slope failure. This was based on the likely range in the liquefied undrained sand strengths and the limited fill heights. Thus the only credible failure mode would be some localized sloughing. In summary, the credible risks associated with liquefaction include localized shallow sloughing of slopes. Although some post - liquefaction settlement is theoretically possible, due to the localized nature of liquefiable zones and the depth to these zones, it is unlikely that any settlement effects would actually occur. 5.2 Stability We completed several stability evaluations using the computer code XSTABL. The results indicated a factor of safety of a deep- seated failure was adequate, generally in excess of 1.5 for even very conservative strength assumptions in the lower fill. These included 4' =24 degrees, c' =0 for drained conditions and 4)=0, c' =500 psf for the undrained conditions. However, the calculated factor of safety was relatively low for shallow sloughing failures along the slopes where the lower loose /soft soils are exposed. This is not surprising and is consistent with the observed scarp that likely occurred about the time that the fill was placed. Calculated seismic stability is adequate related to a deep- seated failure but some localed sloughing could occur. We discussed the possible effects of liquefaction on the slope stability in Section 5.1 above. Golder Associates March 21, 2002 • 8 • 023- 1014 - 100.100 For a range of possible strength parameters, the static and seismic factor of safety against shallow sloughing type of failures is considered marginal for areas where the lower loose /soft fill is exposed and the fill slope is steeper than about 3.5H:1V (16 degrees). 5.3 Foundation and Development of Stable Slopes We considered supporting the houses on spread footings bearing in the upper compact to dense fills. However, we were concerned about the poor quality of the underlying fills and the risk of settlement induced ` e recommend that the sltructu organic be supported one and/or seismic vibrations. Thus, piles founded in the dense, stiff native soils underlying the fill. Specific design criteria are presented in Section 6 below: Although the fill slopes are considered stable with respect to a deep- seated failure, as discussed in Section 5.2 above, areas of steep slopes with exposed loose /soft soils are susceptible to shallow sloughing failures. In general, this risk is considered low as evidenced by the current slopes exhibiting no evidence of recent movement with the current scarp having likely occurred shortly after the fill was placed. However, we recommend that the slopes be modified to reduce these risks in areas that are in close proximity to the proposed houses such as Lots 6 and 7. Section 6 below presents specific recommendations. Golder Associates March 21, 2002 • 9 023 - 1014 - 100.100 6. DESIGN RECOMMENDATIONS 6.1 Foundation Recommendations We recommended that the houses be supported on ouex experience, were recommended that pile foundation options available. Based P auger -cast piles be used. Small-diameter have likely more through the upper dense fills and conventional-sized expensive than auger -cast piles. Below, we present design criteria for auger -cast piles. I other pile types are found top be more economical, we can develop alternative design criteria. Auger cast piles should be augered through soils. Figure 4 shows soils into the d elevations underlying dense /stiff glacially overridden � to the top of this bearing layer. In general, the depth from the existing ground surface to this bearing layer varies from about 10 to 15 o feet e the house locations. We proposed house present the locations to about 20 to 25 feet on the backs following auger- cast -pile design criteria: • MINIMUM DIAMETER We recommend that the piles have a minimum diameter of 14- inches • MINIMUM DEPTH: All piles should be advanced at least 4 feet into the bearing material. For budgeting purposes Figure depending an used n to estimate conditions encoungtered The actual installed pile lengths may vary in the field. • PILE CAPACITIES: The following table presents the allowable axial compression load based on pile diameter and depth penetration ebe based on 14-inch-diameter bearing. piles loads are likely small, the design will probably with the minimum 4 -foot penetration into dense /stiff bearing. * Estimated elevation to top of bearing based on figure 4 For short -term transient loads, the above values can be increased by 1/3. If a load factor design is used, the ultimate axial loads can be assumed to be twice the allowable loads. Settlement is expected to be less than 1/2-inch. Golder Associates March 21, 2002 • 10 111 023 - 1014 - 100.100 • MINIMUM REBAR: Regardless of the structural requirements, we recommended that as a minimum of one small rebar is placed full depth into the grout after auger removal as a check on hole "necking". If the rebar cannot be installed full depth, the pile should be rejected. 6.2 Slab On Grade The first -floor slab and garage slab can be designed as a normal slab -on -grade provided that the existing subgrade is prepared as discussed in Section 5.6. All slabs should be underlain by a capillary break, which consists of at least six inches of sand drainage blanket overlain by plastic sheeting. The drainage blanket should meet the requirements of section 9- 03.13(1) of the 1991 Washington State Standard Specifications for Road, Bridge and Municipal Construction. At the contractor's option, the plastic can be overlain by about two inches of drainage sand. It has been our experience that some contractors feel that the upper sand layer is necessary for proper curing of the concrete. 6.3 Foundation Drainage Normal footing and wall drains should be provided for any building that has interior slabs below the elevation of the adjacent finished ground surface. Below -grade basement walls should be provided with drainage provisions consisting of either a drainage fabric or a clean well graded sand and gravel backfill. Foundation drains should consist of a four -inch- diameter, perforated, rigid, plastic pipe embedded in clean, free - draining sand and gravel, meeting the requirements of Section 9.03.13 and Section 9.03.12(4), respectively, of the 1998 Washington State Standard Specifications for Road, Bridge, and Municipal Construction. A positive means of draining the sand below adjacent floor slabs should also be provided. This could be done with either a separate slab drainage system or cutouts in the footings. Roof drains should be connected to a separate system and not drain into the under drain or wall drain system. 6.4 Slope Setbacks and Regrading As discussed in Sections 5.2 and 5.3, areas of steep slopes with exposed loose /soft soils are susceptible to shallow sloughing failures. In general, this risk is considered low as evidenced by the current slopes exhibiting no evidence of recent movement. However, we recommend the following to minimize the risk of any slope impacts on the utilities or houses: Golder Associates March 21, 2002 • 11 • 023 - 1014-100.100 • HOUSE SET BACKS: The pile caps for all house structures should be located at least 10 horizontal feet from the top of a projected imaginary 3H:1V line from the toe of the slope (18 degrees). This criterion can be met by locating the house away from the top of the slope, by lowering the grades on the backside of the house to create the setback (likely requires a daylight basement), and/or flattening the slopes. In general, this will impact Lots 1, 5, 6 and 7. • UTILITIES: In general, utilities should meet the same setback criteria as presented above. If any utilities must cross the slope, they should be aligned down the fall line of the slope and placed at a depth of at least 5 feet (3 feet at the toe area of the slope), which should be below any active sloughing zones. • DRAINAGE: It is essential to limit any surface runoff down the slope or ponding of water above the slopes. Thus all surface drainage should be controlled and tight lined before draining down the slope or drained towards the front of the site. Golder Associates March 21, 2002 • 12 • 023 - 1014 - 100.100 7. CONSTRUCTION CONSIDERATIONS 7.1 Subgrade Preparation Since the structure will be pile supported, the existing fills need not be removed. However, the subgrade needs to be stabilized in order to provide adequate support for construction equipment, the slab -on -grade and pavement areas. In general, the near - surface fills are well - graded sand and gravel with minimal silt. Except during very wet weather, this material should provide an adequate subgrade. However, in areas where the upper fill is thin, on the slopes, and/or in areas where the grade is lowered the lower fill may be encountered. This lower fill is generally a wet, fine- grained material that will provide an inadequate subgrade for equipment and construction activities particularly during wet weather. The contractor should anticipate that over - excavation and replacement or a stabilizing layer of fill or ballast may be required in these areas. Use of heavy woven geotextiles in these areas may be warranted. If the soft lower fills are exposed in the excavation for a lower slab the subgrade will need to be stabilize. This should consist of some over - excavated, placement of a heavy woven geotextile, and backfilled with compacted structural fill. The depth of the over - excavation depends on the nature of the unsuitable areas with the intent to provide an adequate subgrade for the slab. In general, the maximum depth of over - excavation will likely be on the order of 18- inches. 7.2 Fill In general mass earthworks will be minimal. Fills placed in areas of pavements and inside the building footprint should be well graded sand and gravel placed in maximum 12- inch -thick loose lifts and compacted to at least 95 percent of maximum dry density as determined by ASTM 1557, Method D. The upper granular on -site excavated fill can generally be used for structural fill provided they can be properly moisture conditioned and contain no organic debris, building debris, or other unsuitable materials. 7.3 Auger Cast Piles Auger cast piles are particularly sensitive to the installation methods and contractor experience. Poor equipment and/or inexperienced contractors can result in piles that are improperly installed and, in the worst case, piles that are completely "necked" providing essentially no significant resistance. Thus, it is essential that auger cast piles be installed by qualified, experienced contractors with the full time construction monitoring of experienced geotechnical field engineers. General monitoring requirements include the auger down pressure, identification of cuttings, grout pressure, the rate of auger withdrawal, and grout take. It is also Golder Associates March 21, 2002 • 13 0 023 - 1014 - 100.100 recommended that as a minimum one small rebar is placed full depth into the grout after ! auger removal as a check on hole "necking'. If the rebar cannot be installed full depth, the pile should be rejected. 7.4 Construction Monitoring Critical geotechnical aspects of construction should be monitored by a qualified geotechnical field engineer. This includes pavement and slab subgrade preparation, placement and compaction of structural fills, construction of wall and footing drains, and installation of the auger cast piles. Golder Associates for this study and conversations regarding the proposed development of the site. Once the site project plans are finalized, we recommend that we be given the opportunity to review the plans and specifications to verify that they are in accordance with our recommendations. The integrity and performance of the auger cast pile foundation system and the development of a suitable pavement/slab subgrade depends greatly on proper construction procedures. Therefore, it is recommended that a geotechnical engineer be retained to provide geotechnical services during the critical aspects of the project. The Golder field borings were performed in general accordance with locally accepted geotechnical engineering practice to provide information for the areas explored. There are possible variations in the subsurface conditions between the borings and variations with in the groundwater conditions with time. We recommend that a contingency for unanticipated conditions be included in the construction schedule and budget. Golder Associates Golder Associates Inc. 18300 NE Union Hill Road, Suite 200 Redmond, WA 98052 -3333 Telephone (425) 883 -0777 Fax (425) 882 -5498 January 15, 2002 Johaus Nalewajek c/o Christopher Olivier 741 S Elmgrove Street Seattle, Washington 98108 ATTENTION: Mr. Johaus Nalewajek RE: PRELIMINARY GEOTECHNICAL STUDY MACADAM ROAD SOUTH RESIDENTIAL PLAT TUKWILA, WASHINGTON Dear Mr. Nalewajek: Golder Associates Our ref: 023 - 1014.000 RECEIVED JAN 2 2 2002 TUKWILA PUBLIC WORKS This report presents the results of our preliminary geotechnical engineering study for your Macadam Road South Property in Tukwila, Washington. This study was performed in accordance with our proposal to you dated January 2, 2001 and represents a review and updating of our earlier report titled "Preliminary Geotechnical Engineering Study, Macadam Road South Property, Tukwila" dated May 20, 1999. We understand that you have obtained permission from Mr. Larry Howe, our client, for us to use the 1999 report. This report is based on the proposed Plat Plan by_Jaeger Engineering dated 11/30/01. The purpose of our work was to evaluate the subsurface conditions particularly as related to the thick existing fills and develop pre liminary _geotechnical recommendations for proposed site development and construction. Thick fills extending to depths in excess of 15 feet underlie the site. The conservative design approach would be to place all foundations below the fills into the native soils. This would require piles or extensive fill excavations. Alternatively, it is also feasible to place the foundations on the existing fills provided some settlement risks are acceptable and the ground modification recommendations below are implemented. To minimize uncertainties and assist in making a decision about foundation design, we recommend that additional subsurface information be obtained for specific structures as discussed in Section 7. 1. SITE CONDITIONS AND PROPOSED CONSTRUCTION The site consists of approximately 1-3/4 acres, which is roughly rectangular in shape and is located between Interstate 5 and Macadam Road in Tukwila, Washington as shown on Figure 2. Figure 1 was prepared from an older site plan that used a different datum than OFFICES ACROSS ASIA, AUSTRALASIA, EUROPE, NORTH AMERICA, SOUTH AMERICA January 15, 2002 2 023 -1014 the newer plan prepared by Jaeger. The elevations shown on the Jeager plan appear to be about 140 feet less than the elevations shown on Figure 1. The site has a relatively level portion adjacent to Macadam Road that extends to about the 'Top of Fill" line shown on Figure 2 at about elevation 330 to 340 feet. From the top of fill, the surface slopes downward at about 3H:1V to 4H:1V to a small swall at about elevation 305 to 310 adjacent to I -5. We observed evidence of a shallow slope failure in the fill as discussed below in Section 4. Currently the level portion of the site is mainly open with tall grasses and small brush. The sloping portion is covered with brush and small trees. We understand over the years that filling and some subsequent excavation of fill has occurred over the years at least three times. This appears to included fill placed prior to 1986, fill placed between 1986 and 1990, and some regrading of the fill after 1990. We reviewed plans developed by Arnett and Associates dated 1990 showing general site layout, lot subdivisions, a proposed subsurface cut -off drain, and a proposed surface drainage system. We understand that the subdrain and surface drainage system were installed. Based on the d on the Jaeger Engineering 11/30/01 plan, the site will be divided into seven lots fronting along Macadam Road as shown approximately on Figure 2. The three houses located on sloping ground will include a daylight basement. Some limited filling and cutting will be required to construct the houses and grade the final lots. .i 2. SUBSURFACE EXPLORATIONS We explored the subsurface conditions by excavating a total of six test pits in early April 1999. The test pits extended to depths of 10 to 15 feet and were located in the areas of the proposed houses as shown on Figure 2. The shallower test pits were terminated above the full reach of the backhoe due to heavy caving. The logs of the test pits are included in Appendix A. The test pits were located by geologist from our firm by pacing from known field locations. Thus the locations shown on Figure 2 should be considered approximate. The geologist logged the soil and groundwater conditions and recorded pertinent information including depths, stratigraphy, soil engineering characteristics, and groundwater occurrence. The stratification depths indicated on the summary logs represent the approximate boundaries between soil types. The soil and groundwater conditions were those recorded at the time of the exploration and may not necessarily represent those at other times and locations. The test pit backfill was tamped in place with the backhoe bucket; however, some settlement over the test pits should be expected. 3. SOIL AND GROUNDWATER CONDITIONS None of the test pits penetrated through the fill that extended to depths of 10 to 15 feet. The fill encountered was variable but consisted primarily of a fine to coarse sand with varying amounts of silt and gravel. Some of the tests encountered minor organics and Golder Associates January 15, 2002 3 023 -1014 building debris in the fill including bricks, chucks of asphalt, pieces of concrete, pipe, etc. The upper 4 to 8 feet were generally compact to dense with the deeper fills loose to compact. The upper compact to dense fill layer may represent the newer fill and the underlying loose to compact fill the older fill. Based on an interpretation of the available data, we have estimated the thickness of the existing fill under the site. This data includes topographic plans from 1986 and today and the test pit results. The 1986 topography implies that fill had been placed in the central part of the site prior to the major filling after 1986. In general, it appears that over the years fill was placed on a sloping site to create a relatively level bench next to Macadam Road. The data implies a fill thickness of about 4 to 8 feet along Macadam Road to a maximum of about 24 feet near the break in slope some 60 to 120 feet from Macadam Road. The fill . thickness thins out essentially zero at the eastern property line next to the Creek. Moderate seepage was observed in all of the test pits except TP -1 that was dry. The depth of the seepage ranged from about 3 to 13 feet with most of the pits indicating a seepage zone at a depth of about 8 feet. Since these seepage zones were within the fill, it is unlikely that they represent the regional groundwater table. It is more likely that seepage zones represent perched water occurring in more permeable zones within the 4. SLOPE CONDITIONS As discussed in Section 1, we observed evidence of a shallow slump feature or scarp in the fill both in Apri11999 and in January 2002. The slump appears to extend across most of the site starting at the top of fill 'slope as a small one to two foot high scarp and extending downslope. We believe that the scarp likely occurred during the first wet season after the fill was placed and involved only the upper 2 to 4 feet of material. There was no evidence of recent slope movement. In general the slopes appear stable however there could be additional minor slouging of the steeper slopes particularly around the scarp feature. 5. LIQUEFACTION RISKS In our opinion, liquefaction risks are low and within the generally accepted levels for these types of projects. Although the existing fills are locally loose and granular, the continuous groundwater table likely occurs at or below the contact with the underlying native soils. Thus the fills are not considered liquefiable. Based on published geologic maps, the site lies outside of the Duwamish valley and any liquefaction hazard areas. The lower portions of the site near the creek may be underlain by a thin zone of loose soils. However even if these soils are liquefaction prone, they are outside the limits of the proposed structures and could only impact back yards. Golder Associates January 15, 2002 4 023 -1014 The scarp feature across the western portion of the site was observed in 1999 and is not considered to have been impacted by the 2001 Nisqually earthquake. ,/ 6. PRELIMINARY FOUNDATION RECOMMENDATIONS Thick fills extending to depths in excess of 20 feet underlie the site. Within the footprint of the proposed houses, the fill thickness likely ranges from 10 to 20 feet. The conservative design approach would be to place all foundations below the fills into the native soils. This would require piles or extensive fill excavations. Alternatively, it is also feasible to place the foundations on the existing fills provided some settlement risks are acceptable and the ground modification recommendations below are implemented. With fill depths exceeding 20 feet, fill excavation is considered uneconomical. The conservative design would involve the use of a pile foundation with the piles founded in native soils below the fills. Several pile types are considered feasible including pin piles, driven wood piles, and auger cast piles. Additional information including borings drilled into the native soils would be required to design the piles. At this time, we feel that auger cast piles would likely be the most economical due to the potential problems of driving the wood and pin piles through the fill into the native soils. A less conservative but more economical design would involve the use of normal spread footings placed on stabilized fill. The fill stabilization should include: • SURCHARGE: A surcharge should be placed over the building areas consisting of placing fill to an elevation of three feet above the final slab elevation for a period of at least two weeks. If the houses are designed with daylight basements, the existing grades may already be in excess of three feet above final grade and no actual surcharge fill need be placed. • PARTIAL FILL EXCAVATION: The entire house footprint should be excavated to a depth of at least two feet below the bottom of the footings. • PROOF - ROLLING AND COMPACTION: With the subgrade at a depth of at least two feet below the bottom of the footings, the entire building area should be proof rolled with a fully loaded dump truck and then compacted with a heavy vibratory compactor. The intent of the proof - rolling is to identify any soft areas in the fill, which would be over - excavated, and backfilled with compacted fills. The intent of the vibratory compactor will be to densify the soils and obtain 95 percent Modified Proctor Compaction within at least the upper 18- inches. • PLACEMENT OF COMPACTED FILL: After completion of the proof - rolling and compaction, a layer of two feet of structural fill should be placed and compacted to a minimum dry density of 95 percent of Modified Proctor Compaction. Provided the debris is removed and suitable compaction can be obtained, the excavated soils can be used. Based on implementation of the above recommendations, the houses could be placed on normal spread footings with slab on grade. The footings could be designed for a Golder Associates January 15, 2002 5 023 -1014 maximum bearing pressure of 2 ksf. These foundations should perform well with minimum long -term settlements less than one inch. However there are some uncertainties related to the possible occurrence of very loose deep fills or fills with extensive debris underlying the houses. This might occur if some of the lots are underlain by a deep filled gully. These types of conditions could result in long -term settlements exceeding one inch or sudden settlements during a major seismic event or ground saturation event (broken water line, clogged downspout drains, etc). Although these risks are considered small, the shallow foundation option is less conservative than the pile foundation option. 7. OTHER PRELIMINARY RECOMMENDATIONS In general, the site can be developed using conventional design and construction procedures except for the foundations as discussed above and the following: • SLOPE SET BACK: We recommend that the footings on the eastern side be located so that an imaginary line drawn downward from the bottom of the footing at a slope of 3H: 1V does not intercept the ground surface. In addition, the footing should be set back a horizontal distance of at least 10 feet from any slope exceeding 4H:1V. In general, provided the houses are constructed as daylight basements, these criteria should be easily met. On a case -by -case basis, these criteria may be relaxed to allow the houses to be situated on the lots. However, relaxation may require implementation of some other criteria. • SURFACE DRAINAGE: Surface drainage should be controlled to minimize runoff down the slope. This would include collection of downspout discharge and runoff from the Macadam road, driveways, and front yards. Under no circumstances should any runoff including downspouts be infiltrated into the ground through "dry wells" or perforated infiltration pipes. • SUBSURFACE DRAINAGE: Wall and footing drains should be designed for any below grade sections of the houses such as the below grade daylight basements. • EARTHWORK SCHEDULE: To the extent possible, the recommended ground modification required for using spread footings be completed during the drier periods of the year. Performing this work during the wet periods of the year will be more difficult and result in higher costs. 8. ADDITIONAL WORK AND USE OF THIS REPORT To minimize uncertainties, finalize design criteria and provide information for the contractor, we recommend that additional subsurface information be obtained. This information should include: • GROUND STABILIZATION AND SPREAD FOOTING OPTION: If ground stabilization and spread footings are selected, the intent of additional work would be to better define the nature of the fills, the likelihood that the fills could contain significant unsuitable materials and help determine the depth of over - excavation. This would likely involve one to two test pies at each house location. Golder Associates January 15, 2002 6 023 -1014 • PILES: If piles are planned, we recommend borings to determine the depth to and nature of the pile- bearing stratum. Two to three borings for all seven lots should be adequate. We recommend that a specific geotechnical assessment with final design recommendations be made of each house foundation and drainage design. This could be done as one report if spec houses are to be built or as separate reports if custom houses are built. Once the site project plans are finalized, we recommend that we be given the opportunity to review the plans and specifications to verify that they are in accordance with our recommendations. This report has been prepared exclusively for the use of Johaus Nalewajek and his consultants for specific application to this project. The integrity and performance of the foundation system depends greatly on proper site preparation and construction procedures. The explorations and engineering analyses were performed in general accordance with locally accepted geotechnical engineering practices. There are possible variations in the subsurface conditions between the borings and variations with in the groundwater conditions with time. We recommend that a contingency for unanticipated conditions be included in the construction schedule and budget. Robert L. Plum, PE Principal RLP /ms 0115r1p1 Golder Associates FIGURES Golder Associates PROJECT NO. 993 1457 DRAWING NO. 82251 DATE 4/12/99 DRAWN BY EA FIGURE 1 SITE VICINITY MAP HOWE/MACADAM/WA Golder Associates 0 1 111 Lot 1 Lot 2 Lot 3 Lot 4 Lot 5 Interstate S Creek Lot 6 Lot 7 T ' -3 / 40 80 FEET TP -2 Macadam Road S. LEGEND TP -j • 11 11 11 11 11 11 11 11 11 11 1 11 -J TP -2 Test pit designation and location FIGURE 2 SITE EXPLORATION PLAN NALE WAJ E K/MACADA M/ W A PROJECT NO. 0231014_000 DRAWING NO. 82252 DATE 1/09/02 DRAWN BY ETF Golder Associates APPENDIX A Golder Associates Associates Temp. 50° Weather Partly cloudy Equipment Cat 416C Extendahoe FIELD TEST PIT LOG Engineer T. Sager Operator Dean Test Pit TP 3 Contractor Owner Date 4/8/99 Location East end between lots 4 and 5 Elevation -340' Datum MSL Job 993 1457 E 0 — 5 — 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 — 15 — 20 10 15 20 W Samples No Depth 1 0.5-4' 2 5 -8' Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L 0 -0.5 Sod 1030 13.5' 2.5' Perched -LJ 13' ^ `J 0.5 -4.0 Compact, mottled, light dive gray and light dive brown, silty fine to coarse SAND, trace gravel, trace cobbles, trace asphalt. moist (FILL) Special Notes L/ 4.0 -13.0 .Dense compact, dark gray, silty fine to coarse SAND, Seepage noted at 2.5' and 13' /trace gral el, trace cobbles, trace asphalt, moist to wet (FILL) Moderate caving in the upper half of the test pit Fill was less dense in wet portion below 9' PROJECT NO. 993 1457 DRAWING NO. TP -3 GATE 4/19/99 DRAWN BY EA jGo1der Ass es Temp 45° Equipment Weather Partly cloudy Cat 416C Extendahoe FIELD TEST PIT LOG Engineer T. Sager Operator Dean Test Pit TP 1 Contractor Owner Date 4/8/99 Location West end between lots 6 and 7 Elevation -340' Datum MSL Job 993 1457 E — 0 — 5 — 10 —15 0 — 20 5 10 15 20 W Samples No Depth 1 2 -10' PROJECT NO. 993 1457 DRAWING NO. TP -1 DATE 4/19/99 DRAWN BY EA Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L ID 0-0.5 Sod 0930 0 NA 0945 12' 0 0.5 -10.0 Compact to dense, mottled, Tight olive gray and Tight olive brown, silty fine to coarse SAND, little fine to coarse subrounded gravel. moist (TILL/FILL) Special Notes 10.0 -12.0 Compact, Tight olive brown, fine to coarse SAND, little No caving, no seepage observed boulders, trace gravel, trace wood debris (REMNANT TOPSOIL/BASAL FILL) PROJECT NO. 993 1457 DRAWING NO. TP -1 DATE 4/19/99 DRAWN BY EA Temp. 50° Weather Partly cloudy Equipment Cat 416C Extendahoe FIELD TEST PIT LOG Engineer T. Sager Operator Dean Test Pit TP 2 Contractor Owner Location West end between Tots 4 and 5 Elevation -340' Datum E —5 — 10 — 15 Date 4/8/99 MSL Job 9931457 —► W 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 — 20 5 10 15 20 No 1 2 Depth 1 -2' 7 -10' PROJECT NO. 993 1457 DRAWING NO. TP -2 DATE 4/19/99 DRAWN BY EA Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L XJ 0 -0.5 Sod 1000 0 9.5' 1015 10' 0 0.5 -3.0 Compact. mottled, Tight olive gray, silty fine to coarse SAND, little fine to coarse subrounded gravel, trace concrete. asphalt and misc. debris. moist (FILL) Special Notes V 3.0 -10.0 Loose to compact, mottled, dark gray and dark brown, Moderate caving throughout full depth of the test pit _ fine to coarse SAND, little silt, little concrete, pipe.ard asphalt debris. little organics as decomposed4wigs and grass. trace brick fragments, moist to w(rt (FILL) Heavy seepage below -9.5' . Debris were up to 18' x 12' x 4' Couldn't see much below 10' due to groundwater so test pit was terminated PROJECT NO. 993 1457 DRAWING NO. TP -2 DATE 4/19/99 DRAWN BY EA Associates Temp. 50° Weather Partly ctoudv Equipment Cat 416C Extendahoe FIELD TEST PIT LOG Engineer T. Sager Operator Dean Test Pit TP 4 Contractor Owner Location West end between Tots 2 and 3 Elevation -340' E —5 — 10 — 15 Datum Date 4/8/99 MSL Job 9931457 —► W 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 — 20 5 10 15 20 No 1 2 Depth 0.5 -7' 7 -15' PROJECT NO. 993 1457 DRAWING NO. TP-4 DATE 4/12/99 DRAWN BY EA Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L _ 1 0-0.5 Sod 1155 0 -(D1240 15' 13' 0.5 -7.0 Dense, mottled, Tight olive gray and light olive brown, silty fine to coarse SAND, little fine to coarse gravel, trace cobble -sized concrete. trace asphalt. most (FILL) Special Notes V 7.0 -15.0 Loose, dark gray, silty fine to coarse SAND, little fine Moderate to heavy caving below 7' to coarse gravel, trace cobble -sized concrete, trace asphalt. trace organics as woody debrJ wet Moderate seepage below 13' PROJECT NO. 993 1457 DRAWING NO. TP-4 DATE 4/12/99 DRAWN BY EA fGo1der As soc�iates Temp. 50° Weather Partly cloudy Equipment Cat 416C Extendahoe Engineer T. Sager Contractor Owner Location East end between Tots 2 and 3 Elevation E 0 — 5 --10 FIELD TEST PIT LOG Operator Dean Test Pit TP 5 Date 4/8/99 -340' Datum MSL Job 9931457 1 1 1 0 —15 — 20 5 l I I I 1 I I I I 1 I I I I l 10 15 20 W Samples No Depth 1 0.5 -8' 2 8 -14' PROJECT NO. 993 1457 DRAWING NO. TP -5 DATE 4/19/99 DRAWN BY EA Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L XD 0-0.5 Sod 1300 0 1315 14' 8' 0 0.5 -8.0 Dense, mottled, light olive gray and light olive brown. silty fine to coarse SAND, trace fine to coarse gravel, trace asphalt. trace woody debris. moist (FILL) Special Notes V 8.0 -14.0 Loose dark gray, silty fine to coarse SAND, trace fine Moderate caving at 8' and below to cc rgegr vel, trace asphalt, trace woody debris, wet (FILL) Water seepage at 8' ( -3 qpm) PROJECT NO. 993 1457 DRAWING NO. TP -5 DATE 4/19/99 DRAWN BY EA 2Go1der Associates Temp. 50° Weather Partly cloudy Equipment Cat 416C Extendahoe FIELD TEST PIT LOG Engineer T. Sager Operator Dean Test Pit TP 6 Contractor Owner Location North end of site north of lot 2 Elevation -340' Datum N — 0 —5 — 10 Date 4/8/99 MSL Job 9931457 —.- S 0 — 15 — 20 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 10 15 20 Samples No Depth 1 0.5 -3' 2 3 -13' PROJECT NO. 993 1457 DRAWING NO. TP -6 DATE 4/19/99 DRAWN BY EA Sample Descriptions and Excavation Notes Time Depth of Hole Depth to W/L 0-0.5 Sod 1320 0 ..0 1345 13' 7' 02 0.5 -3.0 Compact to dense, light olive gray, silty fine to coarse SAND, little fine to coarse gravel, trace asphalt, trace woody debris. moist (FILL) Special Notes -3 3.0 -13.0 Loose gray, silty fine to coarse SAND, little fine Water seepage on south end of TP at depth of 7' to c rse gavel, trace asphalt, trace woody debris, we (FILL) Moderate caving at 3' PROJECT NO. 993 1457 DRAWING NO. TP -6 DATE 4/19/99 DRAWN BY EA • City of Tukwila Steven M. Mullet, Mayor Department of Community Development Steve Lancaster, Director Christopher Olivier 3805 S. 150 Street Tukwila, WA 98188 RE: L2000 -077 Dear Mr. Olivier, Thank you for your submittal of 12/4/2001. The Public Works Department has reviewed it and I have attached Dave McPherson's comments. It appears that additional work is needed regarding the geotechnical evaluation of the site and the storm drainage plan prior to issuance of the SEPA determination. As a reminder a sight distance study and street lighting plan will be required with your miscellaneous permit submittal for construction of the frontal improvements. If you have any additional questions or comments, please call me at (206) 431 -3670. Sincerely, Nora Gierloff Associate Planner Enclosure CC: Dave McPherson, Public Works C:Wora's Files \LETTERS \Olivierl -8.DOC 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone: 206 - 431 -3670 • Fax: 206 - 431 -3665 MEMORANDUM TO: PLANNING DEPT. — Nora Gierloff, Associate Planner FROM: PUBLIC WORKS DEPT. - David McPherson, As Ora Engineer DATE: January 4, 2002 SUBJECT: Nalewajek — 7 Lot Short Plat 13900 — 48th Ave. South (Macadam Rd. South) Short Plat Comments Short Plat - L2000 -077 1. Geotechnical issues have not been resolved, for this project. The primary report by Golder Associates Inc., dated May 20, 1999, was peer reviewed by Shannon & Wilson, Inc.. Shannon & Wilson's letter of August 16, 2001, concluded that further geotechnical studies are required. The cost of all additional and required geotechnical peer review, shall be at owner's expense. 2. The most recent storm drainage plan and drainage report, have been reviewed by Ryan Larson, P.E., Senior Surface Water Management Engineer. The storm drainage system is not adequate as proposed. The Engineer may contact the Public Works Department, and arrange a meeting with Ryan, me, and John Howat, Superintendent of Sewer & Surface Water. 3. The documents provided to the Public Works Department in December, 2001, relating to previous grading, drainage, and erosion control measures for this site, do not mitigate the requirement for additional geotechnical studies. June 7, 2001 • cry of Tukwila Steven M. Mullet, Mayor Department of Community Development Steve Lancaster, Director Christopher Olivier for John Nalewajek 3805 S. 150'x' Street Tukwila, Washington 98188 Re: Nalewajek Short Plat, File Number L2000 -077 Nalewajek SEPA, File Number E2000 -032 Dear Chris Olivier: The short plat permit application and SEPA Checklist submitted to the City of Tukwila has been reviewed. The following comments have been made to the short plat application file number L2000 -077. I will revise comments to the SEPA Checklist prior to final approval and determination. Public Works Department Comments • Peer review of the geotechnical report is required_per the City of Tukwila codes 18.4 and-? i .04.140.A. The applicant is required, and has agreed verbally, to bear cost of peer review and geotechnical reports and studies. Until this time, the following additional comments apply to the short plat application submittal: • Combine the driveways. This is a required common driveway. Show the easements for these driveways. • Storm drainage system needs to be redesigned to include detention and water quality treatment of the public roadway drainage system before it can be discharged to the WASHDOT system. • Show utilities, both existing and proposed, in the street cross. • Provide the following notes on the short plat site plan: a. The plan shall comply with the geotechnical Engineering Report. by Golder and.Associates, dated May 29, 1999, and subsequent geotechnical reports. b. No runoff shall be infiltrated, including downspouts, into the ground through dry wells nor perforated infiltration pipes or trenches. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone: 206 - 431 -3670 • Fax: 206- 431 -3665 • Letter to Christopher Olivier/ on behalf of John Nalewajek Nalewajek Short Plat. File Number L2000 -077 Nalewajek SEPA Checklist. File Number E2000 -032 Page 2 c. Individual house foundation and drain system shall provide a specific geotechnical assessment with final design recommendations. Information Items: Prior to approval of a building permit, the following items will be required: a. WASHDOT approval is required to discharge storm drainage water within the right of way. y y b. You will need to obtain a preliminary plat approval and then a miscellaneous permit to install all common infrastructures. c. The 8 inch water pipe is in conflict with the roadway drainage system. Coordinate Water District #125 plan with the civil engineering site plan and roadway plan. It will need to be removed. The 4 foot waterline within the street is also in conflict. Correct the site plan to avoid these conflicts. d. Provide a cross drainage agreement between lots. e. Show location of wetland drain on the civil plan. • A street lighting plan will be required. • A sight distance study will be required. Fire Department Comments • A second fire hydrant will be required. Lot 6 and Lot 7 do not meet the 150 foot travel distance required for fire hydrants. Please review and respond to the comments on your project. Attach a revision Submittal Form. A copy of this form is enclosed with this letter for your convenience. Sincerely, 77 Alexa Berlow Associate Planner • L !L '( • Attachment CC: David McPherson, Associate Engineer, Public Works Department Steve Kohler, Lt. /Fire Prevention Officer, Fire Department • • • To: City Of Tukwila Dept. Of Community Development Re: 13900 48th Ave So. Short Plat The topographical lines displayed in your application are pre -1980s And not related currently. We witnessed the disposal of thousands of yards of various materials dumped on this property. This was over a three year span of 1987 thru 1990. This dump site received as follows: cement re- inforcing steel brick and mortar stumps and logs landscaping debri all sizes of rock pit run asphalt wheels various soils gravel We do not consider this site acceptable for our neighborhood. RAY VOMENICI 4822 So. 138th. RECEIVED JAN 3 1 2001 COMMUNITY DEVELOPMENT • • MEMORANDUM TO: PLANNING DEPT. — Alexa Berlow, Associate Planner FROM: PUBLIC WORKS DEPT. — David McPherson DATE: January 23, 2001 SUBJECT: Nalewajek Short Plat 13900 — 48th Ave. South SEPA, Short Plat and Misc. Comments SEPA — E2000 -032 1. Project to comply with Geotechnical Engineering Report, by Golder Associates, dated May 20,1999 and subsequent geotechnical reports. The environmental checklist should be revised as follows: A. Background 10. Building Permit SApproval from WSDOT to discharge storm drainage within their Right of Way 13. Portion of parcel is class 2 and 3 landslide hazard area B. Environmental Elements 1. Earth - 11,1 lni4 tvi„t%-"r- b. 30% c. See Geotechnical Report d. See Geotechnical Report e. Structural Fill, surcharge, foundation excavation — see Geotechnical Report g. Approximately 20% per storm report by Civil Engineer h. Construction entrance, silt fence, straw bales, and other methods per King County Surface Water Design Manual 2. Air a. Dust during construction and exhaust emissions from construction equipment b. Emissions from traffic on 48`h Ave South (Macadam Rd) c. Dust control note on civil site plan sheet 5. Animals birds — The site will remain partially native and is near native areas. Many common species of birds may be on the site on occasion. mammals — Many common species of rodents and small mammals may be on the site on occasion. 8. Land and Shoreline Use h. The site contains areas of Potential Geologic Instability Class 2, and Class 3 (See Soils Report). There is a watercourse along the East end of the site, which may be classified as Type 3. 14. Transportation d. Addition of approximately 3 feet of asphalt roadway, curb & gutter, and sidewalk. Storm drainage system for roadway drainage. 16. Utilities b. Electricity - Natural Gas - Telephone - Water — Water District # 125 New 8" waterline required along site Sanitary Sewer — Val -Vue Sewer District Short Plat — L2000 -0077 1. Provide note on short plat, to comply with Geotechnical Engineering Report, by Golder Associates, dated May 20, 1999 and subsequent geotechnical reports. 2. Provide note on short plat, that no runoff, including downspouts, shall be infiltrated into the ground through "dry wells" or perforated infiltration pipes and trenches. 3. Provide note on short plat, that individual house foundation and drainage system, shall provide a specific geotechnical assessment, with final design recommendations 4. Provide easement and show on short plat, for required common driveways. Informational Comments 1. Coordinate Water District # 125 plan, with civil engineer's site and roadway plan. New 8" water in conflict with roadway drainage system. 2. Abandon or remove existing 4" waterline within street? 3. Proposed storm detention system on steep slope. Verify construction and maintenance access plan and procedures. 4. A cross drainage agreement between lots, will be required. 5. Show utilities, existing & proposed, in the street cross - section. 1 • 6. WSDOT approval required, to discharge storm water within their Right -of -Way. 7. Show on civil plan, where the wetlands drain to. 8. Provide street lighting plan. 9. Provide sight distance study. 10. Combine driveways. 11. See geotechnical report — soil stability issues to be resolved, prior to Building Permit. 12. Per the geotechnical report, provide additional subsurface information as needed. • • City of Thkw Department of Community Development • • Steven M Mullet, Mayor NOTICE OF APPLICATION DATED: JANUARY 9, 2001 Steve Lancaster, Director The following applications have been submitted to the City of Tukwila Department of Community Development for review and decision. APPLICANT: John Nalewajek LOCATION: 13900 48th Avenue South FILE NUMBERS: L2000 -077 (Short Plat, Seven 171 lots) PROPOSAL: Proposal for a seven lot short plat including a wetland stream OTHER REQUIRED LAND USE PERMITS: E2000 -032 SEPA (State Environmental Policy Review) These files can be reviewed at the Department of Community Development, 6300 Southcenter Blvd., #100, Tukwila, WA. Please call (206) 431 -3670 to ensure that the file(s) will be available. OPPORTUNITY FOR PUBLIC COMMENT You can submit comments on this application. You must submit your comments in writing to the Department of Community Development by 5:00 p.m. on January 31, 2001. For information on the date and time of the public hearing, please contact the Department at (206) 431 -3670. If you cannot submit comments in writing by the cutoff date indicated above, you may still appear at . the hearing and give your comments on the proposal before the Planning Commission. If you have questions about this proposal contact Alexa Berlow, Planner -in- charge of this file. Anyone who submits written comments will become parties of record and will be notified of any decision on this project. APPEALS You may request a copy of any decision by the Planning Commission on a project or obtain information on your appeal rights by contacting the Department of Community Development at 431 -3670. A decision from the Planning Commission may be appealed to the City Council. DATE OF APPLICATION: NOTICE OF COMPLETE APPLICATION: NOTICE OF APPLICATION POSTED: November 28, 2000 December 15, 2000 January 10, 2001 6300 Southcenter Boulevard, Suite #100 0 Tukwila, Washington 98188 0 Phone: 206 - 431 -3670 0 Fax: 206 - 431 -3665 • City of Tukwila Steven M. Mullet, Mayor Department of Community Development Steve Lancaster, Director NOTICE OF COMPLETE APPLICATION December 29, 2000 Chris Olivier for Johan Nalewajek 3805 S. 150th Street Tukwila, WA 98188 RE: Nalewajek, Johan Short Plat, Seven (7) Lots Short Plat L2000 -077 ` SEPA Checklist E2000:0327 Dear Chris Olivier: Your applications, on behalf of Johan Nalewajek, for approval of a short plat and a State Environmental Protection Checklist for a seven (7) lot short plat at, 13900 48th Avenue South, have been found complete, as of December 15, 2000. Within the next 14 days, you will need to attach a laminated notice form on a notice board. All short plats that propose more than seven (7) lots and that require a SEPA determination require a notice period. For instructions and timelines to install a notice board on the site, please refer to Attachment B - Public Information Signs in the application packet. I will notify you when this laminated form is ready for you to pick up. After the form has been installed, please drop off a signed Affidavit of Posting to show proof that the notice board and proper notices have been installed. You will be responsible for removing the notice board from the site once your application has been approved and finalized, and when all public comment periods have terminated. This determination of Complete Application does not preclude the City to request revisions to your proposal through the formal project review phase that has now commenced. Your application will be routed to appropriate departments for internal review, and any revision comments made back to you within 21 days of this notice. This is to insure that your proposal meets the substantive requirements of the zoning code and goals of the Comprehensive Plan. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone: 206 - 431 -3670 • Fax: 206 - 431 -3665 Nalewajek Johan 1 File NumberL2000 -077 (Short Plat) File Number E2000 -035 (SEPA Checklist) •otice of Complete Application Page 2 If you have any questions about this notice, or if you wish to speak to me sooner than my next response date, please do not hesitate to contact me as planner -in- charge of your project at (206) 431 -3673. Sincerely, Alexa Berlow Associate Planner cc: Reviewing City Departments • CITY OF TUKWILA • Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3670 RECEIVED CITY OF TUKWILA NOV 2 8 2000 PERMIT CENTER SEPA APPLICATION CHECKLIST FOR STAFFUSE_ONLY. Planner ecetpt ° Number: Applicant notified of incomplete-,application: Applicant"notifiedofcomplete application::: Notice. of:application;issued :" File Number: Z(.. Cross- reference files: L (� o .04K :. A. NAME OF PROJECT/DEVELOPMENT: IUA e Luce &IG W otA4 5hey).- pla, - B. LOCATION OF PROJECT /DEVELOPMENT. (address and accessors parcel number(s)) 3 ©n r • lidipme:F. Quarter: Section: Township: Range: (This information may be found on your tax statement) C. PROJECT DESCRIPTION: ENVIRONMENTAL CHECKLIST Purpose of Checklist: The State Environmental Policy Act (SEPA), chapter 43.21C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help the agency decide whether an EIS is required. Instruction for Applicants: This environmental checklist asks you to describe some basic information about your proposal. The City uses this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the_best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply ". Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the City staff can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attached any additional information that will help describe your proposal or its environmental effects. The City may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Use of checklist for nonproject proposals: Nonproject proposals refer to actions which are different or broader than a single site specific development project, such as plans, policies and programs. Complete this checklist for nonproject proposals, even though questions may be answered "does not apply ". In addition, complete the supplemental sheet for nonproject actions (part D). • For nonproject actions, the references in the checklist to the words "project ", "applicant ", and "property or site" should read as "proposal", "proposer ", and "affected geographic area ", respectively. CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431 -3670 ADDRESS LABEL REQUIREVIE\ TS The City of Tukwila requires that neighboring residents, businesses and property owners be notified of certain types of pending applications in order to encourage citizen participation in the land use process. Applicants are therefore required to submit the following materials: • Mailing labels listing the owners of record for all property within 500 feet of the boundaries (not the center) of the applicant's site (2 sets or 3 sets, if SEPA review is required). • Mailing labels listing the residents or businesses of any property within 500 feet of the property if they are different from the land owners (2 sets or 3 sets if SEPA review is required). • One copy of an assessor's map(s) showing the boundaries of the subject property and the 500 foot radius. 22ND ST K=`i23ND ST.: Property owner names and addresses can be obtained from the King County Department of Assessment located on the 7th floor of the King County Administration Building, Room 700, 500 Fourth Avenue, Seattle. To compile the information required: • Obtain the assessor's map(s) which._contain(s) your property and all neighboring properties within 500 feet (See example diagram). You may use the maps on file in the Assessor's Office or purchase a set from the King County Department of Public Works Map Counter on the 9th floor of the Administration Building. Purchased maps must be ordered several hours in advance of the time you would like to pick them up. • After securing the assessor's maps, obtain a "Real Estate Inquiry Batch Request Sheet" from the Department of Assessment. On this form provide the tax account number for each affected property as shown on the assessor's map(s) and submit the completed form to the Department of Assessment with the appropriate fee. Applicants can request that the information be printed in mailing label form or on standard paper. To obtain occupants /resident/business names and addresses, consult the Kroll maps located in the Tukwila Department of Community Development and then visit the site to determine resident names and unit numbers. The information on the mailing labels may refer to "Resident" or "Tenant ", with the proper mailing address, if the specific name is unknown. ENVIRONMENTAL CHECKLIST A. BACKGROUND Control No. Epic File .No. Fee 325 Receipt No. 1. Name of proposed project, if applicable: `,1d 4 litaeu ark 2. Name of applicant: ha in W Qilpwa,j &lc 3.. Address and phone number of applicant and contact person: (° ULirI VI �Y` O I V I BV 4. Date checklist prepared: il 0100 5. Agency requesting Checklist: City of Tukwila U 6. Proposed timing or schedule (including phasing, if applicable): 0 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. /PO 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. see ca :Act c h i e c / c t4 �- 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. RIO • • 10. List any government approvals or permits that will be needed for your proposal. 11. Give brief, ':complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. Section E requires a complete • description of the objectives and alternatives of your proposal and should not be summarized 'nere. p / fn '7 /d Location of the proposal. Give sufficient information for a person to understand t� _..//____the._.precise:location of your._propos.ed project, including a street address, if any, and section,. township, and range, if known. -If a proposal would - occur —over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applica- tions related to this checklist. 9d0 i If 2cI 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? 4/0 TO BE COMPLETED BY APPLICANT B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): - Flat, hilly, steep slopes, mountainous -, other b. What is the steepest slope on the site (approximate percent slope)? /0 c. What general types of soils are found on the site (for example, clay,) 411111k peat, muck)? If you know the classi 'cation • agricultural soils, specify them and note any prime farmland. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. e. Describe the purpose, type, and approximate quanti- ties of any filling or grading proposed. Indicate source of fill. 00 rill edec - f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? /0 Evaluation for Agency Use Only Evaluation for Agency Use Only h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: ///Q�{j 2. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile odors, industrial wood smoke) during construction and —wften -.„ the project is completed? If any, generally describe and give approximate quantities if known. Da l"W b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. POW r A/'D' c. Proposed measures to reduce or control emissions or other impacts to air, if any: Water a Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year - round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. Q • Evaluation for Agency Use Only 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please ,describe and attach available plans. ,t' 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. poi tfE 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quan- tities, if-known. /U ON — — — 5) Does the proposal lie within a 100 -year floodplain? If so, note location on the site plan. pokJT Pow 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume, of discharge. A/ WE' • • Evaluation for Agency Use Only b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quan- tities, if known. 2) Describe waste materials that will be discharged into the ground from septic tanks or other sour- ces, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. Alt2N a. V Water Runoff (including storm water): ' 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. See tut/lied 600,01&cir Evaluation for Agency Use Only 2) Could waste materials enter ground or surface waters? If so, generally describe. /JO 0 Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: e al-ct oh eel cCnccc�v,P4 4. Plants a. Check or circle types of vegetation found on the site: V / deciduous tree: alder, maple, aspen, other evergreen tree: , cedar, pine, other shrubs V grass pasture _ crop or grain _ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other water plants: water lily, eelgrass, milfoil, other V other types of vegetation b. What kind and amount of vegetation will be removed or altered? I f er S' tr , c. List threatened or endangered species known to be on yoN ____ or near the site. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: 002 /PE- . Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: birds: hawk, heron, eagle, songbirds, mammals: deer, bear, elk, 'beaver, other: fish: bass, salmon, trout, herring, shellfish, other: e b. List any threatened or endangered species known to be on or near the site. /700(e— c. Is the site part of a migration route? If so, explain. d. Proposed measures to preserve or enhance wildlife, if any: '30/ fTEY 4" -TivC japT_ Evaluation for Agency Use Only Evaluation for Agency Use Only 6. Energy and Natural Resources What kinds of energy (electric, natural gas, oil, wood stove, color) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. 1 r, T12 l G / /V 14• it 2 L4 L- all-S Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: IVO 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. A/O 1) Describe special emergency services that might be required. /V0 / 2) Proposed measures to reduce or control environ- mental health hazards, if any: MONe Evaluation for Agency Use Only b. Noise 1) What types .of noise exist in the area wn_� affect your project (for example: 4110 equipment, operation, other)? 2) What types and levels of noise would be created by or associated with the project on a short - term -term basis (for example: traf- fic, construction operation, other)? Indicate what ours noise would come from the site. 7 - 3) Proposed measures to reduce or control noise impacts, if any: fc901/4" 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? 1//'51./9/1tr L)9 -)V1) b. Has the site been used for agriculture? If so, describe. (� c. Describe any structures on the site. /VY2/I/• • Evaluation for Agency Use Only d. Will any structures be demolished? If so, what? /Mxi_ e. What is the current-zoning classification of the site? ,57/1-006 "f4 114/1-V f. What is the 'current comprehensive plan designation of the site? 7 fht/'l /c--4'. t7[?04 S g. If applicable, what is the current shoreline master program designation of the site? M914/6' - Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. i. Approximately how many people would reside or work in the completed project? pplyr— /1"bti.) j. Approximately how many people would the completed project displace? _j LW1 /1/'ow k. Proposed measures to avoid or reduce displacement impacts, if any: ZOWi Now 1. .Proposed measures to ensure the proposal is com- patible with existing and projected land uses and plans, if any: NO Evaluation for Agency Use Only 9. Housing a. Approximately how many units w. . be provided, if any? Indicate whether high, middle or low - income housing? '7 fi e,i b. Approximately how many units, if any, would be. eli- minated? Indicate whether high, middle, or low - income housing. IVO c. Proposed measures to reduce or control housing impacts, if any: 4/0/7i, 10. Aesthetics a. What is the tallest height of any proposed . structure(s), not including antennas; what is the principal exterior building material(s) proposed? 2 V" V//vol, s rA b. What views in the immediate vicinity would be altered or obstructed? /{7010- c. Proposed measures to reduce or control aesthetic impacts, if any: 6453F f,Ei/4P Gz.EF'1' /y Gl0 coil' TY2.44ct''N Evaluation for Agency Use Only 11. Light and Glare a. What type- of light or glare will the proposal produce? What time of day would it mainly occur? Fr 1,4 h o vs til i Liyh b. Could light or glare from the finished pro1� a safety hazard or interfere with views ? /,z c. What existing off -site sources of fight or glare may affect your proposal? 1V0�t d. Proposed measures to reduce or control light and glare impacts, if any:• /Ubi1t/ Os Recreation a. What designed and informal recreational oppor- tunities are in the immediate vicinity? , 'Pie b. Would the proposed project displace any existing recreational uses? If so, describe. /ye• c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: /VD%e Evaluation for Agency Use Only 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or pro- posed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. PP/DG E b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. Nonl c. Proposed measures to reduce or control impacts, if. any: 1/l9/V1✓ 14. Transportation a. Identify public streets and highways serving the site, and describe proposed accss to the existing street system. Show on site •lans, if any. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? c. How many parking spaces would the completed project have? How many would the project eliminate? 16 Sra L 0.1 gatlage 'v 2 A vite1r ho le 7 ho v s..6 j /1/dil I /o ` 4/i2 41 )1. Evaluation for Agency Use Only d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). pi/I.. 3a Cs„ x e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. iyO f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. 1/_L,0mo g. Proposed measures to reduce'or control transpor- tation impacts, if any: 4k-0h.6 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. A/'2 b. Proposed measures to reduce or control direct impacts on public services, if any. /ft9 16. Utilities a. Cir - tiliti- -.tly av ilable at.the site: electricit at.rala water efuse service,: to ephone, sanitary sewer, septic system, other. b. Describe the utilities that are proposed for the project, the utility providing the service; and the general construction activities on the site or in the immediate vicinity which might be needed. C. Signature The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: 0-YA: d&e.e.e/ - Date Submitted: PLEASE CONTINUE TO THE NEXT PAGE. 11/ Evaluation for Agency Use Only • TO.BE COMPLETED BY APPLICANT Evaluation for Agency Use Only D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (do not use this sheet for project actions) Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not imple- mented. Respond briefly and in general terms. _1. How would the proposal be likely to increase discharge to water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? 'I -cpiq/ pit /+�.. 4111/ tin/ c:i9 ou I I1(y clA r_ l,. /6� /2 ) Proposed measures to avoid or reduce such increases are: /100`C 2. How would the proposal be likely to affect plants, ani- mals, fish, or marine life? OG?e Proposed measures to protect or conserve plants, ani- mals, fish, or marine life are: mire 41 Sta j h 4 v4L 6, Evaluation for Agency Use Only 3. How would the proposal be likely to deplete energy or natural resources? a41/ !249fi• Proposed measures to protect or conserve energy and natural resourses are: L1� e, op ' //,' 64- hobo 6.N 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetla ds, floodplains, or prime farmlands? IAl4 C, 2, e-J Proposed measures to protect such resources or to avoid or reduce impacts are: rnie YJ eeceect 5. How would the proposal be likely to affect land and shoreline use, inclduing whether it would allow or encourage land or shoreline uses incompatible with existing plans? /40 g f fE.GI�' Evaluation for Agency Use Only Proposed. measures to avoid or reducre shoreline and land use impacts area: 0,10f ip/iCCiiie How does the_ proposal conform to the Tukwila Shoreline Master Plan? 110f pl icabi °L 6. How would the proposal be likely to increase demands on transportation or public services and utilities? I_ _ n' ii /A ' ie Proposed measures to reduce or respond to such demand(s) / °!� rnf7 3 /r are: 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of-the environment. ) s d rcc flit of Loqh c #14/6 Evaluation for Agency Use Only 8. Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? WC. Proposed measures to avoid or reduce the conflict(s) are: • TO BE'COMPLETED BY APPLICANT Evaluation for Agency Use Only E. SUPPLEMENTAL SHEET FOR ALL PROJECT AND NON PROJECT PROPOSALS The ,objectives and the alternative means of reaching the objectives for a proposal will be helpful in reviewing—the aforegoing items of the Environmental Checklist. This information provides a general overall perspective of the proposed action in the context of the environmental infor- mation provided and the submitted plans, documents, suppor- tive information, studies, etc. 1. What are the objective(s) of the proposal? RO((L1L 7 MPir) 60li e5 2. What are the alternative means of accomplishing these objectives? NO e- 3. Please compare the alternative means and indicate the preferred course of action: • • 4. Does the proposal conflict with policies of the Tukwila -Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? Proposed measures to avoid or reduce the conflict(s) are: /v014 ( -23- Evaluation for Agency Use Only 1AIGER ENC INEER IG 9419 S. 204 PLACE - KENT, WASHINGTON 98031 PHONE (253) 850 -0934 FAx 1253) 850-0155 October 20, 2000 PRELIMINARY DRAINAGE REPORT NALEWAJEK- OLIVIER PLAT 13900 MACADAM ROAD TUKWILA, WA. PREPARED FOR: Applicant: Chris .Olivier 3803 S. 150th St., Tukwila, WA. 98.188'. (206) 228 -7649 PREPARED BY: James J. Jaeger, P.E. PARCEL NO. 152304 -9072 RECEIVED NOV , 2 8 2000 COMMUNITY DEVELOPMENT I. OVERVIEW The proposed plat will create 7 single family residential Tots from an existing 1.72 acre undeveloped parcel. There are no existing improvements on the parcel. The 7 new lots will be long, narrow lots that extend the width of the site, with lot widths varying from 50 ft. to 75 ft. The new Tots will all have frontage along Macadam Road S. and all will gain access from driveways that are connected directly to this existing road. The site is the location of a previous large fill operation. It is estimated that over 25,000 CY of fill were placed on the site in 1990. This operation was performed under a King County Grading Permit (C9001981). A copy of those permit conditions is attached at the end of this report. All of the proposed Tots will get water and sanitary sewer connections from the existing mains within Macadam Road. The site is immediately west of the 1 -5 freeway. The freeway right -of -way is the east property line of the site. Macadam Road S. is the west property line. The width of the property between the two ROW's varies from 225 ft. to 100 ft. The fill was placed within the west half of the site, along the Macadam Road frontage. The fill is in excess of 10' to 15' deep, as determined by soil logs and a geotechnical report by Golder Associates (May 20, 1999). The fill creates a fairly level "pad" along Macadam Road. This pad tapers from 100 ft. wide at the north end to 0 ft. at the south end. This pad will be the primary location for the proposed houses. The Golder report includes recommendations for the house construction. The eastern half of the site is a primarily a 20 ft. high bank created by the fill slope. This bank slopes down to the east towards the freeway at a 3:1 slope (30% + / -). There is an intermittent stream along the edge of the freeway, adjacent to the site. This stream corridor has spawned several small wetland areas. Two of these small wetlands have entered the site and are mapped. These wetlands are shown on the plans. The existing parcel is generally covered with low pasture grass and shrubs with a few trees in the lower slope area near the wetlands. This vegetation is primarily the native plants and grasses that grew on the fill material over the last 10 years. The Macadam road frontage is currently asphalt with a gravel shoulder. The road is crowned, but there is no ditch along the shoulder. The. runoff from the road flows onto the site and is collected by the temporary drainage system installed during the fill process. This system discharges into the wetland /stream area at the base of the slope against the freeway ROW. LC) PUGET SOUND SEE MAP kagitavAigi 1!- r7.24•77 (3) 67•.•1.7. III y •. 4 63 din S --_- -may T but - 67- -L11 - -- uM �� r dIOil GOY t Lot 36 Acres I f000 t.•. AL C. C. LCIU 11468 7000 •'AL . 10 K t(wtcer Art) rn.rai 81 7,00o "4 !N sr. 0 al ep 4..... 04 I 41.. 139TH Sr 7 4 114 • ' S /39TH ST „., „ o •., Corr. orrpFMOUC ..CM4)S 5r OP j ..t •C yl SCM.01SI 406 M. (C00MCs 06 6C. 61•0 Mel WOOL 017161C 05.65 •L. ••.,,,K nl11 Olt 44. LEGEND c.•..,..•..•• 0 DES p ~•.. f• I,..N Mw ..A. Loo_ /44TH-- •—• ATLAS OF $TATTLE 40..40.1170 6 ru61114400 04 KNOLL MAP COMPANY. INC.. SEATTLE SCALE. • O.CM • 200 r([7 • SUN VALLEY DISTRIBUTING, INC. OWNER SITE ADDR: SITE CITY: TELEPHONE: MAIL ADDR: MAIL CITY: RCDG DATE: SFLEFRICES ZONING . LAND USE : LEGAL SUB /PLAT : CENSUS TR: LOT ACRES: STORY /STY: BEDROOMS : BATH —F3H : FIREPLACE: SEWER . HEAT MTHD: WTRFR TYP: PHONE NO. : 509 457 3601 = scum ac a cac ca_zuc i " -. - - E- -,•- 7AX Cr.:MP REPORT NALEWAJEK JOi-I :'. 0 TUKW ILA 425 -747 -1745 104 E RACE S. 1 TAX ID# . 655 GRID: F3 STRUCTURE S LAND $ T0: ASSM1 S IMPROVED: LEVY CODE . 1999 TAXES$ PARCEL TYP: VOL: NGRHD CODE: BLDG ID# . YEAR BLT . EFFYR BLT : YAK: "%` -1a _ WA ��9e. 3203 11/05/99 £aCISE #: 70,000 =EEL: TYP: WARRANTY LDR 901 VACANT, PESILENT -AL SIR 152304 TPxLOT 72 PCR GL 1 & OF BLOCK . 1.72 LOT SF 74,923 DEV TYPE: ABV GRD SF: C 0 0 :CT FIN SF: RSM FIN SF: PUBLIC BSM TOT SF: TOT ELD SF: WTRFST FT: BLD CND: BLD QTY: BLD MAT:.. BSM TYP: GAR TYP: TOT UHT: Jul. 12 2000 08: 07AM P9 :523.049072 SE 15 23N 04E 77000 77,000 2413 1,,249 ;.'NELATTFD PAGE: 024005 VIEW . VW —MTN: VW —CTY: VW —SND: VW—LK . VW -LRV: NONE II. PRELIMINARY CONDITIONS Since this project is a residential development with over 10000 square ft. of new impervious surface, it will be subject to a full drainage review. It will also be subject to the drainage detention requirements. CORE DRAINAGE REQUIREMENTS 1. Discharge at Natural Location: The site will continue to discharge at the natural location. This location is at the northeast corner of the site where the new site drainage system will discharge into the existing wetland and stream that runs along the eastern property line. 2. Off -Site Analysis: A downstream drainage analysis has been performed and is detailed in section III of this report. 3. Runoff Control: This project will provide the standard Level 1 runoff control as specified in the 1998 King County Surface Water Manual. The KCRTS method of analysis will be used. The detention pipe will provide the storage. 4. Conveyance System: The onsite conveyance system has been calculated to handle the 100 year peak rate developed storm event. 5. Erosion and Sedimentation Control Plan: An erosion control plan will be prepared and submitted as part of the engineering plan set. 6. Maintenance and Operation: Operation and maintenance will be performed by the homeowners. A section in the report outlining maintenance procedures will be provided. 7. Bonds and Liability: The required construction and maintenance bonds will be determined by the City and executed for this project. 8. Water Quality: The site is exempt from water quality because it is adding less than 5000 SF of new impervious_surface subject to vehicular traffic. • , • III. OFFSITE ANALYSIS REVIEW OF RESOURCES The following resources were used in the preparation of this section: 1. King County Wetland Inventory Reports: There are no wetlands shown in this report, but small wetlands were field located on the site. 2. King County Surface Water Management Reconnaissance Report shows the beginning of an un -named stream along the eastern edge of the site. 3. Generalized topog. map from the City of Tukwila. 4. King County Sensitive Area Map Folio - Dec., 1990 • Wetlands: none shown, but field mapped. • Streams and 100 year floodplain: un -named stream. • Erosion Hazard: none on site. • Landslide Hazard: none on site. • Seismic Hazard: none on site. • Coal Mine Hazard: none on site. 5. USGS topography map 6. USDA Soil Conservation Service soils survey. FIELD INSPECTION A visual reconnaissance of the site and the offsite drainage system was performed on Sept 12. The weather was dry. UPSTREAM OFFSITE DRAINAGE CONTRIBUTION There is a rather large upstream area to the west that drains down onto Macadam Road with some of the runoff extending onto the site and into the stream along the eastern property line. The stream also begins south of the site and travels along the eastern property line, the common line with the freeway right -of -way. The stream will not be altered by this project because the eastern portion of the site will remain undeveloped. The runoff from the west will be collected by the new curb and gutter that is proposed for Macadam Road and will be piped directly into the wetland /stream along the eastern property line. DOWNSTREAM DRAINAGE ANALYSIS The site has some minor drainage improvements that include catch basins and piping that was installed as part of the previous grading permit. The catch basins are located along the top edge of the fill and are piped to the lower wetland at the northeast property corner. The stream that runs along the eastern edge of the site and the freeway right -of -way is the primary component of the downstream drainage system. 1. Drainage leaves the site within the stream and travels to the north for approx. 500 ft. This portion of the stream is adjacent to the freeway ROW and flows past the end of S. 138th St. It flows into a wetland area that is approx. 300 ft. north of S. 138th St. This wetland area collects smaller swales coming in from the west and southwest. 2. The wetland area has an outlet to the north. This also is in the form of a stream than flows within a deeper swale. The stream crosses under S. 136th St. at approx. 1000 ft. past the site within a culvert. The stream then continues to the north for approx. 500 ft. and crosses under 48th Ave. S. within a culvert. 3. The stream continues within a network of culvert sections and open ditch sections behind the houses and buildings along the west side of S. 134th Pl. There have been reports of occasional overtopping within sections of this segment of the stream. corridor. SUMMARY The downstream drainage from this site will be discharged into the Stream thafflows along the western edge of the 1 -5 corridor. This is a major drainage channel and continues to be a main drainage corridor until its discharge into the Duwamish River. The stream is well defined and is maintained by the City as necessary. The history of problems along S. 134th PI. is said to be a result of an undersized culvert at the north end of S. 134th Pl. It is also said that the problem is cured when this culvert is periodically cleaned. The developed drainage system will include a Level 1 flow control structure and as such, should not have any significant effect on the downstream drainage system. 1 II�r � i I SIRZ l 11 I I �i -- J Of'R,,1 A s bra )0'11' 1� • c9.92 uhI 000 ©L 1 .N 5zb�x (1.; Hl L£I (1 ■ — `! 956'59'1 3 £1£176'911 N 10) b/1 )00611 11 \ / �j 0/2 c9/ 9 MI. 17'30" 1 640 000 FEET 554 • DES MOINES QUADAGLE '7 P• ,t1 02 WASHINGTON-KING CO. 7.5 MINUTE SERIES (TOPOGRAPHIC) kv 122°15' SEATTLE PQ 9 MI. s56 47°30' 5260 180 000 FEET Sc a go • 522 liffinagan • • inigratl V erton. WIV 1 " !EP JIM ningtOn,• ernoriC,1 27'30" 5256 .7.111. • Woo r USGS 114D KAP • • C. DRAINAGE DETENTION The site falls within the area of the County that is designated for the Level 1 flow control standard. This requires a drainage detention system. This detention system will be designed based upon the 1998 King County Surface Water Design Manual. This document uses the King County • Runoff Time Series (KCRTS) as the tool to determine the respective drainage peak flows for various storm events and for the predeveloped and post - developed site conditions. The Level 1 standard requires that the post developed peak flows for the 2 year and 10 year storm not exceed the predeveloped peak rates for the same storm events. The detention storage facility is proposed to be a large diameter pipe located on the slope within the eastern portion of the site. An orifice type flow restrictor will be used to limit the discharge from the storage facility so that it does not exceed the pre - developed flow rates. The detention pipe was sized using the KCRTS program and the defined runoff time series. Summaries of the time series are included within the report. A total length of 288 ft. of 48" diameter underground storage pipe is shown as the detention facility. Three type II catch basins will be located at the ends and in the middle of the pipe. The first type II catch basin at the pipe outlet will be equipped with an flow restrictor riser pipe with 2 orifice discharges. The detail for this catch basin and riser is shown on the plans as determined by the computer program. The computer output sheets resulting from the KCRTS program are attached for reference. The drainage conveyance system that feeds the detention system includes the direct pipe connections from the roof downspouts for all of the new houses. A driveway drain will also be connected to this piping system for each house. The piping design will allow for the inclusion of a rear yard drain for each lot that can collect the rear lawn area runoff before it flows down the bank. All of the new onsite impervious surfaces will be collected by the detention pipe. The respecfive peak flows are summarized as follows: Storm event. Predev. (CFS) Developed(CFS) Pipe discharge (CFS) 2 year: 0.034 • 0.121 0.03 10 year: 0.060 0.145 0.06 The required detention storage volume is 3770 cubic ft. The 48" diameter detention pipe did not include a 6" dead storage depth on the bottom for sedimentation. Since the system is primarily collection roof runoff, sediments are not a concern. Provided detention storage is 3771 cubic ft. including the type II catch basins. An access road to the storage pipe and the flow restrictor will be provided along the north property line. This system will be a private system since it is not collecting the runoff from any public right -of -way. The system will be maintained by the homeowners with a maintenance covenant being executed as part of the final plat documents. D. WATER QUALITY Water quality will not be required by this project. The amount of new impervious surface subject to vehicular traffic is 2800 SF due to the new driveways. There is also approx. 1200 SF of new pavement widening along Macadam Road (only an additional 3 ft.) The total of 4000 SF is under the 5000 SF threshold for requiring water quality control. • • Nor =w� - Li v! 2 pL. T. �121�1N► � CPt._,CUL -P OtiS. vu,t v� j,.■ro-AnrN r1 l `� g g � O' . ce- l.l� oh c 1 MCA-Nu o� a� R2c4ulre-6/ —ttoY) Niot rN ,: 3.770 Lev-e. 10 w cam, Sh 2 . \lo L Pro v i c4.Q.c1) . 44-# t 44 = z 4ca>" ZaS( ,5-1) - 3&27,0 -Pr 3 b� (3) C:'1'Nn s / 4' cffn •. s( = ! S , Q4- 3 (� . s-1� �- O Fr 3(o2-0 + 1S1 = .27 71 F,r,3 ID‘ sc.-\\o-w- Pe -'ro w- Dec . -F(ow Cfow pu o A \c O rCQ (4), (---atr cz-tv1 3. Z 'jr. �� 10 'r . , 121 o 010 O.040 O. I4-S 0, 03 0.o3 CCF-5-) z.2-e' S . Qt-k a, d oar. one cR, : O. 9.0 cAta +f 6/2.: ©, " olka_ a 3,10 o„ bove.. CA Retention /Detention Facility Type of Facility: Tank Diameter: Tank Length: Effective Storage Depth: Stage 0 Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Orifice # Height (ft) 1 0.00 2 3.10 Detention Tank 4.00 300. 4.00 180.00 3770. 4.00 12.00 2 Diameter (in) 0.90 0.86 Top Notch Weir:'None Outflow Rating Curve: None Stage (ft) 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.18 0.28 0.38 0.48 0.58 0.68 0.78 0.88 0.98 1.08 1.18 1.28 1.38 1.48 1.58 1.68 1.78 1.88 1.98 2.08 2.18 2.28 2.38 2.47 2.57 Elevation (ft) (cu. 180.00 180.01 180.02 180.03 180.04 180.05 180.06 180.07 180.18 180.28 180.38 180.48 180.58 180.68 180.78 180.88 180.98 181.08 181.18 181.28 181.38 181.48 181.58 181.68 181.78 181.88 181.98 182.08 182.18 182.28 182.38 182.47 182.57 ft ft ft ft cu. ft ft inches Full Head Discharge (CFS) 0.044 0.019 Pipe Diameter (in) 4.0 Storage Discharge Percolation ft) (ac -ft) (cfs) 0. 1. 2. 4. 6. 9. 12. 15. 60. 116. 182. 256. 338. 425. 518. 615. 716. 821. 929. 1040. 1153. 1268. 1385. 1503. 1622. 1741. 1861. -1981. 2101. 2220. 2338. 2444. 2560. 0.000 0.000 0.000 0.002 0.000 0.003 0.000 0.004 0.000 0.004 0.000 0.005 0.000 0.005 0.000 0.006 0.001 0.003 0.004 0.006 0.008 0.010 0.012 0.014 0.016 0.019 0.021 0.024 0.026 0.029 0.032 0.034 0.037 0.040 0.043 0.045 0.048 0.051 0.054 0.056 0.059 0.009 0.012 0.013 0.015 0.017 0.018 0.019 0.021 0.022 0.023 0.024 0.025 0.026 0.027 0.028 0.028 0.029 0.030 0.031 0.032 0.032 0.033 0.034 0.035 0.035 (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.67 182.67 2674. 0.061 0.036 0.00 2.77 182.77 2786. 0.064 0.037 0.00 2.87 182.87 2895. 0.066 0.037 0.00 2.97 182.97 3002. 0.069 0.038 0.00 3.07 183.07 3105. 0.071 0.039 0.00 3.10 183.10 3135. 0.072 0.039 0.00 3.11 183.11 3145. 0.072 0.039 0.00 3.12 183.12 3155. 0.072 0.039 0.00 3.13 183.13 3165. 0.073 0.040 0.00 3.14 183.14 3175. 0.073 0.043 0.00 3.15 183.15 3185. 0.073 0.044 0.00 3.16 183.16 3194. 0.073 0.044 0.00 3.17 183.17 3204. 0.074 0.045 0.00 3.18 183.18 3214. 0.074 0.045 0.00 3.28 183.28 3309. 0.076 0.048 0.00 3.38 183.38 3398. 0.078 0.051 0.00 3.48 183.48 3482. 0.080 0.053 0.00 3.58 183.58 3559. 0.082 0.056 0.00 3.68 183.68 3629. 0.083 0.057 0.00 3.78 183.78 3689. 0.085 0.059 0.00 3.88 183.88 3737. 0.086 0.061 0.00 3.98 183.98 3768. 0.086 0.063 0.00 4.00 184.00 3770. 0.087 0.063 0.00 4.10 184.10 3770. 0.087 0.373 0.00 4.20 184.20 3770. 0.087 0.937 0.00 4.30 184.30 3770. 0.087 1.670 0.00 4.40 184.40 3770. 0.087 2.460 0.00 4.50 184.50 3770. 0.087 2.740 0.00 4.60 184.60 3770. 0.087 3.000 0.00 4.70 184.70 3770. 0.087 3.240 0.00 4.80 184.80 3770. 0.087 3.460 0.00 4.90 184.90 3770. 0.087 3.660 0.00 5.00 185.00 3770. 0.087 3.860 0.00 5.10 185.10 3770. 0.087 4.040 0.00 5.20 185.20 3770. 0.087 4.220 0.00 5.30 185.30 3770. 0.087 4.390 0.00 5.40 185.40 3770. 0.087 4.560 0.00 5.50 185.50 3770. 0.087 4.710 0.00 5.60 185.60 3770. 0.087 4.870 0.00 5.70 185.70 3770. 0.087 5.020 0.00 5.80 185.80 3770. 0.087 5.160 0.00 5.90 185.90 3770. 0.087 5.300 0.00 6.00 186.00 3770. 0.087 5.440 0.00 Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu -Ft) (Ac -Ft) 1 0.29 * * * * * ** 0.25 4.06 184.06 3770. 0.087 2 0.14 * * * * * ** 0.09 4.01 184.01 3770. 0.087 3 0.14 0.06 0.06 3.96 183.96 3760. 0.086 4 0.14 * * * * * ** 0.06 3.71 183.71 3645. 0.084 5 0.17 * * * * * ** 0.05 3.41 183.41 3426. 0.079 6 0.08 0.03 0.03 2.28 182.28 2220. 0.051 7 0.10 * * * * * ** 0.03 1.38 181.38 1149. 0.026 8 0.10 * * * * * ** 0.02 1.05 181.05 786. 0.018 Route Time.Series through Facility IV. DETENTION ANALYSIS AND DESIGN A. PREDEVELOPED DRAINAGE The drainage from the existing site flows towards the east and into the stream along the east edge of the site. The existing temporary drainage system collects some of the runoff that accumulates on the top of the fill area. This also is piped to the stream. The drainage area used in the calculations will not include the entire site. It will be limited to the western 100 ft. of the site (the west half). The remaining portion will not be developed due to the high, steep fill bank and the wetlands. The existing drainage analysis was performed using the "KCRTS" hydrology software that was produced by the County. Summary computer printouts are attached for reference. The methods outlined in the 1998 King County Drainage Manual were used as guidelines. Following this page are the data sheets used for the computer input data. The computer summary sheets for peak flow. Below is a brief description of the existing drainage characteristics: 2 year peak flow: 0.034 CFS. 10 year peak flow: 0.060 CFS total area:. 1.72 acres developed area: 0.94 acres pervious area: 0.94 acres land use type: till pasture impervious area: none B. DEVELOPED DRAINAGE The developed project will include a drainage detention structure in the form of a subsurface oversized pipe. The existing drainage system installed with the fill area will be abandoned. The developed site will include the roof downspout drains, the driveway drains and the rear lawn areas. The improvements to Macadam Road are not included within the detention system because the amount of the widening is only 3 ft. of asphalt and the sidewalk. It also collects a large amount of upstream offsite runoff that should not be directed into the detention system. Similar to the existing condition, the KCRTS method was used to determine the peak flows for the various storm events. The computer data sheets for the developed flows are shown on the summary page for the detention system summary. The flows are designated as inflow on the time series - results table. A brief summary of the developed drainage characteristics are: 2 year peak flow: 0.121 CFS 10 year peak flow: 0.145 CFS developed area: 0.94 acres pervious area: 0.59 acres land use type: till grass impervious area: 0.35 acres land use type: impervious • • N D - C- RP- � Ro NoFF= vn! DR Pr t r�s P-G� u4-T70 Ras is , 199(6 Ic ,Q Co . Sir c.e.. Derr. flan0a.,( .ct *04=-1 cS'l e , -12 a` s . 6) Clur _ o-� 412 u loo ac2v c orn = 1-12_co S = O, 94- f} S Ft:)...c r = ) D (Res " ktore- 3.2- 2- , Pr) 3 . cRoo C*D J Pr .r ) or en-N-}-\r-,e_ 0\f ex -C,-CYw v1 "q.\ n o Use -'-� l In ..ro\[-e- rY1 e 1's • .v -e- of d I . propos 7 lof T - c� IY l o+ 40 Aew 4-si ll hoave se � oo , 2 ri1ex.K. cirk -e-Lo 6./ 7 (uoc) _ 4 (rv∎fiervio ur 1 p�v�OUS U S� 4. Sails o-r-e. 3 I S 4-00 S . o 94- p,3f = O,S? PIC -rov hC& GesQQ -1C' -hll sO k, (3 (-- f) ,r\' _ / QOO S'F 2200 .3F 0. 3 S Psc.. . Z - p . 034- cis 6)2. = . `24. c-FS Qi o = D , 060 C-F5 Q 10 - O. 0-S cr-s OLIVIER PLAT PEAK FLOW CALCULATIONS USING KCRTS PREDEVELOPED CONDITIONS Flow Frequency Analysis Time Series File:omacpre.tsf Project Location:Sea -Tac - -- Annual Peak Flow Rates-- - Flow Rate Rank Time of Peak (CFS) 0.066 0.025 0.060 0.006 0.034 0.056 0.054 0.113 Computed Peaks 2 2/09/01 18:00 7 1/05/02 16:00 3 2/28/03 3:00 8 3/24/04 19:00 6 1/05/05 8:00 4 1/18/06 16:00 5 11/24/06 4:00 1 1/09/08 6:00 DEVELOPED CONDITIONS Flow Frequency Analysis Time Series File:omacdev.tsf Project Location:Sea -Tac - -- Annual Peak Flow Rates-- - Flow Rate Rank Time of Peak (CFS) 0.137 0.101 0.168 0.098 0.121 0.145 0.142 0.290 Computed Peaks 5 2/09/01 2:00 7 1/05/02 16:00 2 2/27/03 7 :00 8 8/26/04 2:00 6 10/28/04 16:00 3 1/18/06 16:00 4 10/26/06 0:00 1 1/09/08 6:00 Flow Frequency Analysis - - Peaks - - Rank Return Prob (CFS) 0.113 0.066 0.060 0.056 0.054 0.034 0.025 0.006 0.098 Period 1 100.00 0.990 2 25.00 0.960 3 10.00 0.900 4 5.00 0.800 5 3.00 0.667 6 2.00 0.500 7 1.30 0.231 8 1.10 0.091 50.00 0.980 Flow Frequency Analysis - - Peaks - - Rank Return Prob (CFS) Period 0.290 1 100.00 0.990 0.168 2 25.00 0.960 D 145 3 10.00 0.900 0.142 4 5.00 0.800 0.137 5 3.00 0.667 0.121 6 2.00_ 0.500 0.101 7 1.30 0.231 0.098 8 1.10 0.091 0.249 50.00 0.980 weUrno aet - 2.9' 1.615 wit �� °i \4`c —\ ° 167.31 • -• \ / ` o 20 / 1723 \ \ 668 .0 \\ \` 16 �a1tonon \ \ \ 1678 \ ■\ \\ \ AL . \° ° - 6 re„ta 7Sa • \ \\ \ 166 .• 19? ✓794 I 7 ■ \ inter • \_ \� \ \ • • 195.5 165.5 • 1689 \ NOON So' • 1944 • 195.2 \O� \ \-', \ •'199.2 \ . 00.3∎. \ \ 0, ti 2e\ n \, 199 9 \ \ i \ 0 ? \ \ \ ?\ \\ \ \ \ \\ \ \ 1 1 \ •\ \ \ ?\ ?\ ` ` • 172.5 \ \ \ \ \ \ \ \ \ \ \\ \\ ` I A \ \ I \ \\ '' '\ i it i �` ;\ 'Il ' i \ \ 11 , \ \ ? It { •' ' \ 41} ft \ \ 1 II {\ I \ 1 1 q t J a \ \ \ \. \ ` 1 \ D� \ \ \ `1 l i\ht4 i \ \, \\ \ `\ \ \ \ \ \ \ \ \\ i 200.71 . \� i \ ' 1 \ 1 \ ` t\ 4_te ?" o \t0 ] r 7 / V { \ .V j A \ \ I i • l A \\ -2' � 1999 ). 39/ /r1/ I \ 2.7 i- , / / 1 l i \ . ., 1a 7— 29 5\ • ` '\ j 1741 Q 2„ i - •_ 172. ern.9 %,..+4.,e 1 'OOj // .r�• , • 17f2 'i7.o 1-17 \ a' 1948 4: •„ ryr \ j s� 4 176.3 \ \. 2027 \ \ 0 1{i'\ •1P\ 1CO V0' i..evny `ante \\ \ \ \ \ \ \t \. '�b7••d'J' Q 169.7 S PE--\/ F.-1-0FM;✓■7 282 .8 \• 202.6 SECTION 3.2 RUNOFF COMPITfSN AND ANALYSIS METHODS FIGURE 3.2.2.A RAINFALL REGIONS AND REGIONAL SCALE FACTORS ST 1.1 ST 1.0/ ST 1.0 LA 0.8 LA 0.9 LA1.0 LA 1.2 F 3NO "." COUNTY ST 1.1 ST 1.0 Rainfall Regions and Regional Scale Factors Incorporated Area •r,:::) River/Lake Major Road •MACI COUNTY LA 0.8 LA 1.0 9/1/98 3 -22 1998 Surface Water Design Manual 01/02/2000 16:09 4256410514 FRANK_KLEIN PAGE 18 FROM : CFC F 1 NANC I AL • FAX NO. : 425 747 1417 • Oct. 20 1399 03:5 3PM F2 PIE\JIOu5 COo� GRPiDik PAGE: 1 pERIA 1 Activity No C9001981 TYPE; G -RENEW Location: 13900 MACADAM RD S TU GRADING /MINING GENERAL COND'S 0011 - AT LEAST 48 HOURS PRIOR TO THE START OF ANY WORK CALL THE GRADING SECTION AT 296 -6610 TO ARRANGE A PRE- CONSTRUCTION MEETING. AT THE PRE - CONSTRUCTION MEETING THE CIVIL ENGINEER SHALL STAKE THE PROPOSED TOP OF SLOPE AND TOE OF SLOPE. THE TOES OF ALL SLOPES SHALL BE SET BACK A MINIMUM OF 10 FEET FROM ALL PROPERTY LINES 0080 - All work shall comply with the provisions of King County Ordinance 3139, relating to noise control. 0090 - Hours of operation shall be limited to 7:00 a.m. to 7:00 p.m., Monday through Friday. 0120 - Permittee shall abide by the regulations of the Puget Sound Air Pollution Control Agency (PSAPCA). 0140 - You must call I- 800. 424 -5555 not less than 48 hours before beginning excavation where any underground utilities may be located. Failure to do so could mean bearing substantial repair costs (up to three times the cost of repairs to the service). 1020 . Cut/fill slopes shall be constructed in accordance with the recommendations of the soils engineer. During site prepara- tion and grading of this site, permittee shall provide full - time supervision by a licensed geotechnical engineer. 1050 - Only earth materials which have no rock or similar irre- ducible material with a maximum dimension greater than 18 inches shall be used as fill. 1090 - The following statement shall be recorded as a covenant on the property and shall not be changed without express per- mission in writing from King County Building and Land Devel- opment Division or its successor agency: "The fill placed upon this property may not be suitable for structural support. Prior to any future development, a geotechnical analysis shall be submitted to King County Building and Land Development Division addressing the suitability of the fill FROM : CFC. FINANCIAL FAX NO. : 425 747 1417 07t.. 2e 1999 03:54PM P3 for structural support, seismic stability, and settlement." 1110 - All uncontaminated , unsuitable, or surplus excavated soils, construction, demolition, or landclearing (CDL) debris to be removed from the site shall be disposed of or recycled in an approved, legal diposal or recycling site. It will be the permittee's responsibility to locate acceptable disposal or recycling sites and to assure that all surplus material and CDL debris is disposed of in those sites ** CONDITIONS OF PERMIT /APPROVAL PAGE 2 Activity No. C9001981 TYPE: G- RENEW Location. 13900 MACADAM RD S TV DATE: 10/19/99 1120 - Prior to bond release, permittee shall provide a detailed account of all off-site disposal activities. This account- ing shall include date, number of trips, volume, haul route used, type of truck, type of material, and destination, with a complete summary for each separate disposal site. 2020 • The implementation of these ESC plans and the construction, maintenance, replacement, and upgrading of these ESC facili. ties is the responsibility of the permittee until all con- struction is approved. 2070 - Any area stripped of vegetation, including roadway embank- ments, where no further work is anticipated for a period of 15 days, shall be immediately stabilized with the approved ESC methods (e.g. seeding, mulching, netting, erosion blankets, etc.). (KCRS 7.09 D.) 2110 • Stabilized construction entrances and wash pads shall be • installed at the beginning of construction and maintained for the duration of the project. Additional measures may be required to ensure that all paved areas are kept clean for the duration of the project. (RCW 46.61.655.) 2140 - Where straw mulch for temporary erosion control is required, it shall be applied at a minimum thickness of 2 inches. 2200 • The erosion and sedimentation control systems depicted on this drawing are intended to be minimum requirements to meet anticipated site conditions. As construction progresses and unexpected or seasonal conditions dictate, the permittee • , should anticipate that more siltation and sedimentation control facilities will be necessary to ensure complete sil- tation control on the proposed site. During the course of' construction, it shall be the obligation and responsibility of the permitter to address any new conditions that may be created by his activities and to provide additional facili- ties over and above minimum requirements as may be needed to protect adjacent properties and water quality of the receiv- ing drainage system. • 2220 - permittee is totally responsible for the installation and maintenance of the TE/SCP facilities noted on the plan and for bringing to the attention of the Owner /Engineer new con- ditions which may be addressed by these plans. The Contrac- tor shall be held liable for all damages which may result from mis- implementation of this plan or neglect of changing conditions. 7020 - During hauling operations, permittee shall provide effective dust control measures consisting of water, asphalt treated base, chemical dust palliatives, or equivalent measures to control dust from this operation (KCC 21A.22.070.C). 7030 - To prevent tracking of mud and rocks onto King County roads and to comply with RCW 46.61.665(4), permittee shall use a technique approved by King County which is capable of clean- ing wheels, tires, and vehicle undercarriages. 7040 - Permittee shall be responsible for implementing all approp- riate measures needed (i.e paving, sweepers, and /or other techniques) to keep streets and roads used as haul routes. for export or import of material clean and free from debris, mud, etc. 7070 - Any damage to pavement edges, sidewalk, curb and gutter, etc., resulting from operations authorized by this permit shall be repaired immediately. 7080 • Warning signs must also be installed prior to hauling and must conform to the Manual on Uniform Traffic Control Devices. 7100 - Permittee shall provide the name of a responsible person or agent who can be contacted 24 hours a day. 01/02/2000 16:09 N a`« FROM : CFC F I NANC t AL 4256410511 FRR. NK._KLEIN FAX NO. : 42. 747 1417 • Oct. 2e 199:i 07: e5PN P°,• 8210 - Prior to bond release the permittec shall submit verification that the remedial measures for s:npe stablization have been constructed in accordance with the soils engineer's recommendations in the report dated 3!5!91' 8220 - The toes of the fill slopes shall be set back a minimum of ten feet from all property boundaries 8230 - Remedial slope stabilization work shall not commence until a revised drainage and grading plan has been approved by King County. These plans shall address re- design of the fill slopes from 2 1 to 3:1 with the toe of the slope set hack a minimum of 10 feet from all property boundaries and a re- design of the drainage system to reflect the changes in slope in addition, a letter from the soils engineer shall be submitted verifying that their recommendations have been incorporated in the revised plans. 8240 - Prior to bond release, the permittee shall pay a fee based upon cubic yards of fill removed from the site. This fee shall be based upon 1990 King County grading permit operating fees. The permitte shall also pay any outstanding -s associated wfsh review and inspection of draingage plat: :c.iiiOfS. RECEIP /ED • • NOV 2 8 2000 ALTMANN OLIVER ASSOCIATES, L-LC�: DEVELOPMENT ENVIRONMENTAL PLANNING & LANDSCAPE ARCHttLt1I1RE Mr. Chris Olivier 3805 South 150'h Street Tukwila, WA 98188 January 31, 2000 SUBJECT: Wetland /Stream Delineation on Site Located at 13900 Macadam Road (48th Ave. S.) in the City of Tukwila Dear Chris: At your request; on January 17, 2000 I conducted a wetland and stream reconnaissance on the 1.72 -acre subject property (Figure 1). The property has been historically filled and topography on .the site currently consists of a flat area adjacent Macadam Road, with the .remainder of the site sloping down to the north and east towards Interstate Highway:5. Vegetation on.the site consists primarily of.a mixture of low weeds and grasses within the,,upper flat:area, and shrubs and tree ,saplings along the fill slopes. Dominant plant species, are :typical of disturbed. habitats within western Washington and include'Himalayan blackberry (Rubussdiscolor), Scot's broom (Cytisus-scoparius), and red alder (Alnus rubra). One stream was identified flowing from south to north at the bottom of the fill slope along the eastern edge of the property. Most of this stream appears to be located within the right -of -way for Interstate 5. Two small highly disturbed wetland areas were also identified associated with the stream. These small wetland areas extend slightly up the fill slope in the northeast and southeast comers. and appear to be hydrologically supported by poth groundwater seeps and collected drainage discharged from two culverts (one located within each wetland area). Although the wetland area in the northeast corner does contain a single black cottonwood (Populus tr7chocarpa) tree located on a fill pile within the wetland, it consists primarily of a palustrine scrub -shrub and palustrine emergent plant community.dominated by Himalayan blackberry, reed canarygrass (Phalaris arundinacea), and bittersweet. nightshade (Solanum. d_ulcam ara),. , yegetation within the wetland located in the southeast corner :of the site also consists of a :scrub -shrub and emergent plant "community dominated by Himalayan blackberry and reed, canarygrass. In addition,, small red aldertrees;and one larger red alder tree. are located along the edge of this wetland. At the time of > the „January 17, 2000 site visit, soils within both wetland areas were _saturated to the surface and several inches of ponding was observed in places. • . Mr. Chris Olivier January 31, 2000 Page 2 The stream located along the eastern edge of the property would likely be classified as a Type 3 watercourse according to Section 18.45.020 of the Tukwila Municipal Code (TMC). Type 3 watercourses are lower value streams based on their instream features and corridor quality and generally require a 15 -foot buffer plus a 10 -foot residential building setback (TMC 18.145.040.C). The two wetlands on the property would be classified as either Type 2 or Type 3 •dependent_upon whether the City of Tukwila determines that coverage from trees rooted along the wetland edge are actually rooted within the wetland and provide more than a 20% canopy coverage to the wetland. If the trees are determined to provide a 20% or greater canopy coverage, then The wetlands wouldbe-classified as Type.2 wetlands that_generally require a 50 -foot buffer and 10 foot building setback. However, due to the disturbed condition of the existing wetland buffer, it is likely that if these wetlands were determined to be Type 2, a buffer enhancement plan could be implemented that would allow the buffer to be reduced to 25 feet (plus the 10 -foot building setback). If . the trees are determined to provide Tess than a 20% canopy coverage or are not actually rooted within the wetland, then the wetlands would likely be considered Type 3 wetlands that would require 25 -foot buffers (plus 10 -foot building setback). I hope that this information helps you in your development plans for this site. If you have any questions or require any additional information at this time, please call me . at (425) 333 -4535. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC John Altmann Ecologist 3r0 — 305 345. • • _ ▪ 1. ▪ � r • Fgki- Let 7- 3- "�- --+ --^�- 3r0 '— ^•,7f0 1 '`•_. '4 ;:— • ---. r • - • .� ; 4 A /e t6 _ , ✓ �N TZ - - -- . . ..- 325 \ +-t- -- __ 4 ▪ `,...h. 1.1"- - -s. — _ _ _ _:ten •_14 316 Alb .. / • � • r I or-- ° / • ( • 80 ®1eee.. FEET tr DMYaI.]No. atm I% f. 1/2:• e3 I•./.flD? La - .�- - -- -- " -`�` 13800 • -. A ?Ink og1Mer E LOCATIO'4 IA* 40.114 STR EA.M -Pot. SuRvE( *R uSE ma 'To iltE USE-b FOc1:. SITE. p(.4144141N (, Macadam Aoad S' LEGEND 7P -25/ 'rest pit number and �!7 approximate localion %1 Conceptual house r-4/1 location • 349 4111, SITE EXPLORATION 11101VEMAC e;nlrlPr AiS1 LEGAL DESCRIPTION THAT PORTION OF GOVERNMENT LOT 1 AND OF THE STEPHEN COSTER DONATION CLAIM NO. 38, ALL IN SECTION. 15, TOWNSHIP 23 NORTH, RANGE 4'EAST. W.M., IN KING COUNTY, WASHINGTON, LYING EASTERLY OF THE EAST MARGIN -OF 48TH AVE. SOUTH (ALSO KNOWN AS MACADAM ROAD AND AS STATE AID ROAD NO. 1). AND LYING WESTERLY OF THE WEST MARGIN OF PRIMARY STATE HIGHWAY NO. 1 AS ESTABUSHED BY DEEDS RECORDED UNDER RECORDING NO.'S 5484211 AND 5537865, AND LYING SOUTHEASTERLY OF THE SOUTHEAST MARGIN OF SOUTH 138TH STREET (ADOLPH BAKER COUNTY ROAD), AND `•LYING SOUTHERLY OF -A UNE DISTANT SOUTHERLY 110 FEET, MEASURED AT RIGHT ANGLES FRON THE SOUTHERLY UNE; OF SOUTH 138TH STREET. • A °PORTION .of the:S.E: -1/4, :SECTION 15, -TOWNSHIP ' UTILITY CONFLICT .NOTE: CAUTION: THE CONTRACTOR SHALL RE RESPONSIBLE FOR VERIFYING THE LOCATION..OIIENSOI. AND DEPTH - OF ALL EXISTING UTILITIES' WEINER 5•0811 ON'THESE PLANS OR•NOT.BY POTHOLING THE UTILITIES 'AND SURVEYING THE HORIZONTAL AND VERTICAL LOCATION PRIOR TO CONSTRUCTION. VALI' 01=0 THE EMSTCIG 0141TIE5 41 LOCATIONS OF NEW UMW CROO55R+GSSTOPHI'9CALLY Vai4 4 ALL OF • ..101(04(808 NOT CONFLICTS EXIST, -. LOCATIONS OF SAO UTAJ1IES AS SHOWN OI THESE PLANS • ARE NOT GUARANTEED AND ARE SUB.ECT TO VARM110N. . • 23 N., _ RANGE 4 E., W.M. EXPAN5400400R, 0.02 P1. /47• 0.05 Tl. /s7.2 . CEYENT. CONCRETE'. o CE9Tac.-- 11 • :Q •/ •96°' TTR R I RB r - .D . Ca- -5 SIDE ROP ..� • 18- 5 »o3( ' -LINE) NEW T SRE HYDRA,Jr• "NOTE' TOP Or LIP AT DRIWEYATS CEMENT CONCRETE' CURB :do GUTTER. CB. I - oPE Ts-.S4" Wim FLPN'• Ras- RicrOR - Ron 192.o .• LE tE: 104.0 (12•, OIERFLONI" Fa.Ev 110.0 • •/ SOLID, L000UG LtO (S• PE3A1L) . ^ POns"1• FIRE t•IIDRMOT TO BE R�-On D,BPJ»msD S�E�wPLy FRO,. P440,srF_o .C6'9iTiFE lJ- 'FACE of 4094 CIJf✓, , R.M. 114-o D (Pr/ 50L I M V Ir,I( 1E ',.104. A. _,O • CB •'u45. ..I) l .RIM- 145.6 ^ .IE : 192.52 in C" � \ � uPl'EP- oRIPICG . P / v • . FI:£ 5UPP7RT: 3'r •.. / O ' X .RSER wJ °.DI -rp, oRIFI CC DIN: D.9 Ca4., 2' 1Nlo wALL LDCSGwsG LID @ 1 1b.. .. Mir. 3' %PLON3 • �. , _ e .� '»...y MIDPOIUT, CIF PIPE mnOPLe, oRIFC • Et BOW .. 4".42-Fa P.IFIC2 DIA..',- ''1.95 C6`3-,r1FE 11- 48 RIM' 190.5 144.0(3b• WI.60l-!D, - Locz,, -*' L.lb CB' 7 (rYFE R ,1 194 B' .. .. IE:. 191..0 ffi' otn.-conr R15ER w ^SCs -ID, s.00KN•IG LID -M1DROINT OF PIPE' " • Cs" 2 -TYPE II- 54' RIM: 114.0 :. E'. 104.0.( 51. ". Sw 4uE) '16: 12,1.0 (12', SE) 1N/ :AID, LOCL4..o8 LID. 10.. g PACE I. cF CURS 5iL0CUT ' MIr.l. 12 IIJS5TO ZTE 3pus w ROAD ON. REPO 3' ANY. COrPE [CNN CLASS_'' ASPHALT CONCRETE ate' MIN. COYPT DEPTH CRU9 ®-SURFACt4D 7E COARSE p' MW [OWE 0EP7N CORNED 8,04ACNO BASE COIANZ CARREL BASE•(CEASS -TT7 MAT• BE REWAEpDyP�OSAO,N.,O 502 CCNCROAS- O-�J- -"ten -B,. kApeAt') RD. - T`i P. SECT1OI-J LIFT: ROD w/ LIwJD LE FXT51401NIG TD' WI11lnJ 12' -0F " COVER W /ADT. HOCK LOCK, FASTEN TD UPP•A HAND HOLD sm. SALA i'-�- 04 5 LAmEO oR rs(Y� Rea :`Z')-m. • GRADING NOTES 1. Unless otherwise specified. 'on work shoo conform to the 1998 Standard SpeDIRDat1om for road: bridge and municipal construction as published by the WSDOT and the . • APWA, as amendgd by the CIN al tukwlla. All grading acMity shot! conform to UBC Chapter 70. i , - O . 2. These Pions do nat represent the location of on esdsling ut0llles, 11 Is the responsIbllN - o11he contractor to confirm the location and depth 01 existing ut011e, poor to _ - OO , ti The con00c1or shbil be responsible for all safety considerations dudng the execution 4' of the work Inchiding 1 ench shoring per OSHA specincolions ond- tratlic control on • " existing roads. , , - .1. • the engineer shall be notified Immediately upon the discovery of any conflich O :k discrepancies relollve lo-ihese pions.' • , . 5. - AD mbterld used Oi'IW shall be approved all run grovel of native rnaler1011501 hos ' been observed and approved by the engineer. • - 6. AB structural IN material shall be cornpocled to a minimum of 95% MOO {under buildings. roods. driveways. walks. parking lots, elc.l. This 011 ,1100 be compacted - during optimum moisture content In lilts nol•exceeding 12". 5ee arch. specs, - ' "T. .Compocllon'IesIi shall be. taken for on skucturol'Iils a1 the direction o1 the engineer._ 2: CMP" r..7.0%'. '• 054' (LIFER' Rwl 195 1384.N [ORB, GISrea • 3s0EWALic a SP. I+po (FRoP. LsNis) GRAPHIC . SCALE 20 "9 10 .20 - 40: (DI FEET ) 1 Utah- 20 R 1.. THE PRO5ECr /RJtn1 .. 1441: CDNAFLY: WITH 11-1E C- ,EDTEGHUICAo- RERDRT Br GOLDER'Or ASSCC. , .DATT=A . NARY 24, 1409,.•AhiO. ' W B31�SUES•LT' GEDTEr-A4 NI CA.L_ RERDRZTS 2. •0 - RUNDFF 5i•HI.LL • INCJ.IJDIN6 1:0.04 7r2, 0'TD THE C ur..-,D • 11-194,031-1 .010,8 WELTS o0,, PERFFRA'T'ED" :INF.LTRATICN PIPES- OR T14.ENC4•1FS. - 5 �.I0.40l' ■DUAL. HOUSE FoumoA7lON MID .005Pd" • . ` SYS1E). "SHALL. RFDNIDE- A ' . . ^: C- EOTECAJ N1C.344.. ' 0,SSE7MENT WITH FI1^4A11..., . JE5904.0 REC.OIrso 441,ONS. . 1.042' re' WATER1I r GRCRJT 5'rAL P.. ALL .PIPES) wAT6RPGHr SHEAR. • CL:EAIJOUT- GATE(P6R STD. aaarJ:k.C. 0,0440 Si La.) 8. AD Irench bockilll Moleriol shall be compacted l0 957. MOO within roods or 907.' • • outside of traffic areas. 9. RI slopes shall nol exceed 01 and cut slopes Sh00 nol exceed 2:1.: • ,CATCH FS .911.1 10. AO odlocenl roods shall be Sept clean and free from mud and debris. Controcla shall be responsible I01 periodic ioodwoy cleaning.. 11. ConI,ocIor shall lake measures to minimize dust generoled'04 g,oding ocllvllles • including frequent watering by an onsile water bu& it necessary. ' • . ' SCALE: RECEIVED DESIGN By: JJJ .O9 No