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HomeMy WebLinkAboutPermit L94-0085 - PARK PLACE PLAZA - SEPA ENVIRONMENTAL IMPACT STATEMENTL94 -0085 PARKWAY PLACE SEPA CITY OF TUKWILA MITIGATED ETERMINATION OF NONSIGNIFI±o.NCE (MDNS) DESCRIPTION OF PROPOSAL: DEMOLISH OFFICE, CONSTRUCT 150,000 SF RETAIL PROPONENT: LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY: ADDRESS: 17501 SOUTHCENTER.PY PARCEL NO: 262304 -9067 SEC /TWN /RNG: LEAD AGENCY: CITY OF TUKWILA FILE., 1.46- : 94 -0085 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: "'che` cklist and other information on file with the lead agency. This "informatjon is available to the public on request. The conditions to this SEPA Determination are attached. This DNS, is issued under 197 -11.- 340(2.). Comments must be submitted by r 2? agency y w il l not act o n'` this , 1' The lead a enc proposal; for 15 days from. the,-date below:: . L. Ric Beeler, Responsible Official_ City of'._:Tukwila, : (206) 431 -3680 6300 Southcenter Boulevard Tukwila, WA 98188 You may appeal: this determination to the City Clerk at:'Cityr+Hall, 6200 Southcenter Boulevard, Tukwila, WA :. 98188 no later than :101-days from the above signature date by written appeal stating the basis ci,f the appeal for specific factual objections. You may be required to bear some of the expenses for an appeal. Copies of the procedures for SEPA appeals ..are -available with the City Clerk and Department of Community Development. A F F I D A V I T i, Sylvia Schnug Notice of Public Hearing 0 Notice of Public Meeting O Board of Packet jj Board of Packet Adjustment Agenda Appeals Agenda O Planning Commission Agenda Packet Short Subdivision Agenda Packet O F D I S T R I B U T I•O N hereby declare that: O Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit 0 Determination of Non - significance Mitigated Determination of Nonsignificance O Determination of Significance and Scoping Notice O Notice of Action O Official Notice O Other Q Other "12 -2 -1994 was mailed to eachof - the following addresses on Mailed to the Following: DOE- Environmental Review Applicant Puget Sound Air Pollution Control Agency City of SeaTac City Clerk Mayor Attached list of surrounding property owners Name of Project Parkway Place File Number L94 -0085 City of Tukwila Department of Community Development City of Tukwila PUBLIC HEARING NOTICE John W. Rants, A lay( Rick Beeler, DG ?ctc Notice is hereby given that the City of Tukwila Board of Architectural Review will be holding a public hearing at 7:00 p.m: on Dec. 15, 1994 locaied at 6200 Southcenter Blvd. to discuss the following: •I. CASE NUMBER: APPLICANT: REQUEST: LOCATION: PLANNING COMMISSION PUBLIC HEARING , • L94 -0090: Sunshine Ridge - Planned Residential Development Lyle Kussman . Planning Commission recommendation to the City Council for approval of a planned residential development application for a 28 -unit condominium. with 59 parking spaces: Residences will be in 2, 3, and 5 -story. structures. .15200 Macadam Rd. S., Tukwila. :IL • BOARD OF ARCHITECTURAL REVIEW PUBLIC HEARING CASE NUMBER: APPLICANT: REQUEST: LOCATION: CASE NUMBER: APPLICANT: • . REQUEST: LOCATION: L94 -0078: Sunshine Ridge - Design Review Lyle Kussman Board of Architectural Review *approval of the design of the 28 -unit condominium project. 15200 Macadam Rd. S., Tukwila. L94 -0084: Parkway Place 'Parkway. Place Partners ' Demolition of a 9 -story office building and construction • of a 150,000 sq. ,ft. retail space. 17501 Southcenter Pkwy., Tukwila: Persons wishing to comment on the above cases may do so by written statement or by appearing . at the.public hearing. Infcirination on the above.cases,may *obtained atthe Tukwila Planning Division. The City encourages .you to notify your neighbors and other persons you believe• would be affected by the above items. . Published: Seattle Times December 2, 1994 .Distribution: Mayor, City Clerk, Property • Owners /Applicants, Adjacent .Property Owners; File. 6300 Southcenter Boulevard. Suite #100 • . Tukwila. Washington' 98188 .• 12061 efq 1-467n • x'a . I M) 42 1.RRM CITY OF TUKWILA MITIGATED _TERMINATION OF NONSIGNIF1 .,,NCE (MDNS) DESCRIPTION OF PROPOSAL: DEMOLISH OFFICE, CONSTRUCT 150,000 SF RETAIL PROPONENT: LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY: 17501 SOUTIiCEN:TER4:P�1'. °`'tom 262304 - 906:7'.: �.� ADDRESS: PARCEL NO: SEC /TWN /RNG: r•rar.:M -r LEAD AGENCY: J CrITY.;OF;. ,n;%rj;r, TUKW;ILA f,, r {f: $ �gFyILE N�:, 694 -008'5 The• City has14,deter mi'nved,t tha,tn' the p,rop1osa 1 does ilipt fla�ve a4 pr•04b 1 e s i gn i f i can teiad`vers"e i mpact on th'e.;':en'y i onment . ,Nn, en,v i r;onr en.ta;l, impact statement) is not requir,e under RCW 43.21c.03Q(2Y p( This decision ;i'as`' made after rev'i &w;'of; a comp°1 eted env i ronlnenta � �'chefck°1 i st and other,jnformation "on file wit'h.,,th,e' lead agency. Tfais1' i„nt'orma,tion is avail�a,tile;1;to; thefL'pub1ic. on request:-.,._ The conditions <<to th;iss' SE,PA Determination are a:.ttached -.... ....�... �� i r t�:l r" fir# ; r.: a ,_;.tom 1 �. f%"'''b ^1, ., This DNS is i ssu ,d ru.nlder ~1,97- 1;'�;� ,340 (�2„)•. j��omments Y h .- -''..4,T h e\, 1 e a d a g e n c y—w l )r1 1 propos�a,lf for.x1�5 dayS.,fro ,:lthe td'a•'te bel�or+._.v r'. �� 4 L. R c Beil7j.r`�Responsible Officials City • of 1 ikw,i�lpa e'206) 431 -3680 y 6300. So ,t'hceq,•ter• Bou �,evard • 0 L•c4 Tukwila,MIP. 98188 f.� '( / e• "fr{ ti "I �r�1 r`re All 0 You may appe.al���thi�s* determi'na,t on to the City°C1erk at'` Cit, � a11, 6200 Southcenter B o,uhlevard Tukwila, WA:�a98�1:8'8r no later,'thanl.�'1O:�days from the above signature�da,e by written appeal stating the basj of the appeal for .specific factual: objections:- CormIRDe requiredi�o ear some of• the expenses for. an;3pp;eal. fa .,edir0 Copies of the proceduresf.'o "t��SERA;a_�r� .eals�w�i'he av" ble with the City Clerk and Department of Common •iLt y_;De,v ^e,;o.,pment. i? �,'1 �• F 0 d must be subm ttesd by ct not a on "tihis • MITIGATED CONDITIONS OF APPROVAL • Issuance of a Mitigated Determination of Non- significance for•this project is appropriate, as no probable significant adverse impacts on the environment can be foreseen as a result of this project. The following mitigation measures are required as a part of this project: • 1. . New easements must be provided and .recorded.for storm, water and sewer lines that . are for public or mutual .use. New easements must be provided for all utilities that are relocated in conjunction with. this project. New easements. must include • abandonment of existing easements where applicable. 2. The peer review consultant retained by the City, .Shannon & Wilson, reviewed the geotechnical report.for the project. Specific recommendations by Shannon & Wilson with respect to wall design for hillside stability will be followed in .conjunction with • . applicable permits. This includes, but is not limited to, the use of a tied -back soldier pile.wall, three -foot minimum . freeboard, and concrete.facing-over wood lagging on the wall (verbal recommendation from Paul Grant, 11-29-94); 3. • • The conditions established by the City ,Urban Environmentalist, Gary Schuli,, and, .documented in his letter of November 28,• 1994, .will be followed with .respect' to . implementation of the City tree regulations (TMC .18.54) and Sensitive Areas Ordinance (TMC 18.45) in conjunction with .applicable permits. • 4. Storm water drainage will be accommodated ' . per recommendation of the City Department of Public Works. • 5. The transit stop and shelter adjacent to the, project must be retained. 6. The ability: to comply with City noise and nuisance.ordinances (TMC 8.22 and 8.28) must be demonstrated for planned grading, demolition, 'crushing and construction • . activities. • . 7. • The ability to comply with City ordinances . governing. asbestos • removal must • demonstrated for planned asbestos removal. • • It must be demonstrated that construction of the new 48" storm sewer will not undermine the stability of the retaining wall in conjunction .with applicable permits.. • CASTELLO LAND CO INC 4730 32ND AVE S. SEATTLE, WA 98118 LEVITZ FURNITURE CORP 212 HIGH ST POTTSTOWN, PA 19464 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIF IC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PAR ;WAY PROPERTIES INC 720 3 RD AVE SUITE 1700 SEA' 'TLE, WA 98104 HAROLD R IVERSON 1252 GREEN LANE BURLINGTON, WA 98233 MIKAMI MASAO PO BOX 256 DUBLIN, OH 43017 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 'LEVITZ FURNITURE CORP .212 HIGH ST POTTSTOWN, PA 19464 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 A F F I D A V I T 0 Notice of Public Hearing fJ Notice of Public Meeting O Board of Packet fl Board of Packet Adjustment Agenda Appeals Agenda J Planning Commission Agenda Packet O Short Subdivision Agenda Packet O F D I S T R I B U T I O N ' hereby declare that: fl Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit f Determination of Non - significance Mitigated Determination of Nonsignificance O Determination of Significance and Scoping Notice [Notice of Action O Official Notice 0 Other Q Other was AaTligi to each of the following addresses on f2' -1 -4/4' -VI/1ms' erks-y 0/0-711`e,(4-t Name of Project 12(&kk OMB Signature File Number Lq`C 00 1K�7 • CITY OF TUKWILA MITIGATED TERMINATION OF NONSIGNIFI' DESCRIPTION OF PROPOSAL: DEMOLISH OFFICE, CONSTRUCT 150,000 SF RETAIL PROPONENT: ICE (MDNS) LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY: ADDRESS : 17501 SOU THCEN:TER; PAY,`. :!: PARCEL' NO: 262304- 9O6.Z��:'::::�?'"-- -'. + "'"' ', SEC /TWN /RNG: l .x'r r, LEAD AGENCY: ,�;y:;�CrITY• OF,;�YT;UKW'ILA A V UPIL.E> NO: f I (. * 6� 4,,' ../ *;-p t.;, 1 +i S'd fig The City hasjjdeterinined that ,the p,roprpsai doee'ot ha�re,� significant{ adver.-s�e im act on the'eirvpronment. Ari> envi ,on statement �� EIS) is nbtorequir *ed4under R=CgW 43.21�c.03Q(2Z)t( ' decision was made after rev�i;e.�wk�af( a completed environpenta and otherC 11nfo4rm:ation'� on f lfe wi thr the'` 1 ead agency. TI�i is avai lfa;ble to.;,�t�he�;pub1 icon request The conditions to Determi n.a`ir i on are attached:-.-----,—.4,4 �.+� 1 ,y, , This DUNS is is °su `d under `197 -41,341.4.41 i lC�omme, ,ts _ _ 4 _ �. ,, 7r-- --'.--- ',,,The\ 1 e a d' a g efic ..1 11 • propose. for ti1�5 days;�from the d�a\te be1.o �„. . 7j \ i L. Ric B e \l..e•r Responsible Official' gat City of T- %kwic•la,'1 C'206) 431 -3680 6300 Southcen:t l � em. Bou evard I L �0 Tukwila, \NA 98188 k , �y }. r c b94 -0085 prO\b1e enTaj impact WtheW ist inf'o rM on this S A 0000 subm`i tie o't 7 0 must be not act 0 y You may appe`a�1:,thilti{ determi`nap on to the C4,110C1erk gait +City 4 a11, 6200 above�s i tnatur�eiaGedb Twrwtten �aWAea98s+tat stating the n t'`�thesa from ea appeal the g �.,,f �, Y appeal y.�; 9 ,/ , pp for •specific fa ctu :a ,,ob j ect i onsL:�• �� You' $y be requ i re, t'o,,'bear some of the expenses for an; a'ppea1 . ' „,,,1 ;s ;;"�`�r ,--,:d64,,,57 ti. . �1 `'.`• 'vs, Yew' ' : s Copies of the procedure- f;;oryPA „j;,t EaRpea,l �# e .aval l ab l e with the City. Clerk and Department of Commumi,ty_; De,vehopme'rrt. A F F I D A V I T I, Sylvia Schnug ]Notice of Public Hearing f Notice of Public Meeting LI Board of Adjustment Agenda Packet []Board of Appeals Agenda Packet []Planning Commission Agenda Packet Short Subdivision Agenda Packet O F D I S T R I B U T I O N ' hereby declare that: O Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit Determination of Non - significance Mitigated Determination of Nonsignificance fl Determination of Significance and Scoping Notice 0 Notice of Action O Official Notice O Other Q Other was,Bla,k-nd to each of the following addresses on 12 -1 -94 FAXED TO THE FOLLOWING: Roy Bennion, Parkway Place - 325 -4954 Dale Morimoto, WSDOT - 440 -4805 Bob Kimmerling, WSDOT - 586 -4611 Doug Johnson, METRO - 684 -1860 Name of Project QO ( IN P(i2(J. signature File Number IM If 00% A F F I D A V I T Notice of Public Hearing Notice of Public Meeting O Board of Adjustment Agenda Packet Board of Appeals Agenda . Packet Planning Commission Agenda Packet 0 Short Subdivision Agenda Packet O F D I S T R I B U T I O N hereby declare that: ONotice of Application for Shoreline Management Permit []Shoreline Management Permit []Determination of Non - significance 0 Mitigated Determination of Nonsignificance Determination of Significance and Scoping Notice ❑ Notice of Action 0 Official Notice 0 Other Q Other Fcmc was ed to each of the followin addresses on 12- --/- cl �a� g �[ l 0 ) 2 —Z -- q vvq. Name of Project FilVi14.-PA44 Pia Signature File Number r,q (( V-t City of Tukwila John W. Rants, Mayor Department of Community Development Rick Beeler, Director City of Tukwila PUBLIC HEARING NOTICE Notice is hereby given that the City of Tukwila Board of Architectural Review will be holding a public hearing at 7:00 p.m. on Dec. 15, 1994 located at 6200 Southcenter Blvd. to discuss the following: I. CASE NUMBER: APPLICANT: REQUEST: LOCATION: R. PLANNING COMMISSION PUBLIC HEARING L94 -0090: Sunshine Ridge - Planned Residential Development Lyle Kussman Planning Commission recommendation to the City Council for approval of a planned residential development application for a 28 -unit condominium with 59 parking spaces. Residences will be in 2, 3, and 5 -story structures. 15200 Macadam Rd. S., Tukwila. BOARD OF ARCHITECTURAL REVIEW PUBLIC HEARING CASE NUMBER: APPLICANT: REQUEST: LOCATION: CASE NUMBER: APPLICANT: REQUEST: LOCATION: L94 -0078: Sunshine Ridge - Design Review Lyle Kussman Board of Architectural Review approval of the design of the 28 -unit condominium project. 15200 Macadam Rd. S., Tukwila. L94 -0084: Parkway Place Parkway Place Partners Demolition of a 9 -story office building and construction of a 150,000 sq. ft. retail space. 17501 Southcenter Pkwy., Tukwila. Persons wishing to comment on the above cases may do so by written statement or by appearing at the public hearing. Information on the above cases may be obtained at the Tukwila Planning Division. The City encourages you to notify your neighbors and other persons you believe would be affected by the above items. Published: Distribution: Seattle Times December 2, 1994 Mayor, City Clerk, Property Owners /Applicants, Adjacent Property Owners, File. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington' 98188 • (206) 431-3670 • Fax (206) 431-3665 July 24, 1995 City of Tukwila John W. Rants, Mayor Department of Community Development Steve Lancaster, Director Mr. Roy Bennion Park Place Partners 800 Fifth Avenue Suite 3700 Seattle, Washington 98104 Re Park Place Geotechnical Addendum Dear Roy: I have reviewed the most recent letter from your geotechnical engineer regarding a change in building technology for a portion of the retaining wall on this project. I note that the grading of the slope for this portion of the wall must be revised to a slope of 3H:1V, rather than the 1.75H:1V as previously planned. Please note that this additional graded area must be revegetated before final inspection takes place on this portion of the project. This requirement is from our Sensitive Areas ordinance, TMC 18.45.080(e)(3)(B): Where any portion of an area of potential geologic instability is cleared for development, a landscaping plan for the site shall include tree replanting with an equal mix of evergreen and deciduous trees, preferably native, and approved by the Director DCD. Replacement vegetation shall be sufficient to provide erosion and stabilization protection. Please give me a call if you have any questions. Sincerely, /*/z77— Diana Painter Associate Planner cc Joanna Spencer Duane Griffin Jack Pace 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431 -3665 Geo Pi Engineers City of Tukwila Department of Community Development 6300 Southcenter Boulevard, Suite #100 Tukwila, Washington 98188 Attention: Mr. Stephen Lancaster, Director JJuly`21, 1995': d4'E �''. ra _ .. J� [4 ; t �v��r,.•:�, DEVELOP! N J Consulting Engineers and Geoscientists Offices in Washington, Oregon, and Alaska Sensitive Areas Disclosures Tukwila Municipal Code Chapter 18.45 Park Place Project 17501 Southcenter Parkway Tukwila, Washington File No. 3944- 004 -RO1 This letter is intended to meet part of the requirements of Tukwila Municipal Code Chapter 18.45, which includes a letter from the project geotechnical engineer that addresses sensitive areas on the project site. These requirements were outlined in a letter to Mr. Roy Bennion from the city of Tukwila Department of Community Development dated July 19, 1995. Based on our participation in the project during the design phase and in the portion of the project constructed to date, it is our opinion that the portion of the plans and specifications which address the geotechnical elements of the project does conform to the recommendations we provided in our report dated November 10, 1994, two addenda to that report dated March 6 and May 1, 1995, and consultations on various geotechnical design issues which were summarized in various memoranda and letters. It is our opinion also that the risk of damage to the development site from soil instability (namely, the hillside in the western portion of the site) will be minimal, subject to the recommendations we provided in the various correspondence items referenced above. And finally, it is our opinion that the development will not increase the potential for soil movement related to the hillside. GeoEngineers, Inc. 8410 154th Avenue N.E. Redmond, WA 98052 Telephone (206) 861 -6000 Fax (206) 861 -6050 Pr(nted on iecyoled!paper tWor ufo 1' rye:.`.' 1 . ���.. 2+ r�'. %i6'm"w' +?'Yriv'�kiC';'ss`�, #.. �5 '•'�'sp.� City of Tukwila ( July 21, 1995 Page 2 A field design change has been made for the south portion of the retaining wall which extends partially across the south ravine which flanks the hillside. This design change is described in our memorandum dated July 14, 1995 and has been reviewed and approved by WSDOT and the city's geotechnical review consultant for this project, Shannon & Wilson, Inc. • O ■ We trust that this information will meet your present needs. If additional information concerning sensitive area issues is required, please contact us. HRP:JKT:cms Document ID: 3944004.SEN cc: Park Place Partners 800 Fifth Ave., Suite 3700 Seattle, WA 98104 Attn: Mr. Roy Bennion Turner & Associates Architects 18420 - 24th Pl. N.E. Seattle, WA 98155 Attn: Mr. Howard Turner Yours very truly, GeoEngineers, Inc. a_ ,4.41"4,4,_ Herbert R. Pschunder, P.E. Senior Engineer aLL- Jack K. Tuttle, P.E. Principal G e o E n g i n e e r s File No. 3944- 004 -R01 TURNER & ASSOCIATES ,; July 21;1995 Mr Steve Lancaster Department of Community Development City of Tukwila 6300 Southcenter Blvd. Tukwila, WA. 98188 Attn: Ms Diana Painter Associate Planner RE. Park Place Tukwila, WA Sensitive Areas Overlay Zone TMC 18.45.080(e)(5) Dear Steve, 18420 24th Place N.E., Seattle, WA 98155 (206) 365 -7431 JUL. t 'I )99' DEVELOPMZ. Per your request dated July 19, 1995 and the requirements of the above referenced TMC section, I am submitting this letter of notation regarding the design drawings, along with the enclosed letters from the geotechnical engineer and the owner. I have reviewed the geotechnical report, understand its recommendations, have explained the risks of loss due to slides on the site, and have included in the design measures to reduce the risk of injiury or damage, to a degree reflacting the common practices represented by the codes in force and common industry practices, that might be caused by any earth movement on the site. Sincerely, Howard R. Turner, AIA cc: Roy Bennion, GeoEngineers encl: letters from GeoEngineers and P3 P- 3/PARKWAY, L.L.C. 800 FIFTH AVENUE • SUITE 3700 • SEATTLE, WASHINGTON 98104 -3122 • (206) 682 -6868 • (FAX) 682 -1040 i,20'July=1995 Mr. Steven Lancaster Director, Department of Community Development City of Tukwila 6300 Southcenter Blvd., Suite #100 Tukwila, WA 98188 Dear Mr. Lancaster: ,,itt 211995 This letter is notice to you that the owners of the Park Place Retail Center, P- 3/Parkway, LLC agree to and will comply with the provisions of the Tukwila Municipal Code Chapter 18.45, specifically, that we understand and accept the risks of development in an area with potentially unstable soils and that we will advise, in writing, any prospective purchasers of the site of the slide potential of the area. Thank you for your cooperation. Sincerely P- A ' ., AY, LLC Bennion City of Tukwila John W. Rants, Mayor Department of Community Development Steve Lancaster, Director July 19, 1995 Mr. Roy Bennion Park Place Partners 800 Fifth Avenue Suite 3700 Seattle, WA 98104 Re Park Place Dear Roy: According to our Sensitive Areas Overlay Zone (TMC Chapter 18.45), certain assurances are required of applicants for developments with sensitive areas on the site. The following letters must be on file prior to issuance of a building permit for projects with sensitive areas (see TMC 18.45.080(e)(5)). 1. Submit a letter from the geotechnical engineer who prepared the geotechnical report stating that in his judgement, the plans and specifications conform to the recommendations in the geotechnical report; the risk of damage to the proposed development site from soil instability will be minimal subject to the conditions set forth in the report; and the development will not increase the potential for soil movement. (Note: Further recommendations signed and sealed by the geotechnical engineer shall be provided should there be additions or exceptions to the original recommendations based on the plans, site conditions or other supporting data.) 2. The architect or structural engineer shall submit a letter of notation on the design drawings that he or she has reviewed the geotechnical report, understands its recommendations, has explained or has had explained to the owner the risks of loss due to slides on the side, and has incorporated into the design the recommendations of the report and established measures to reduce the potential risk of injury or damage that might be caused by any earth movement on the site. 3. The applicant /owner shall submit a letter to the City stating that he understands and accepts the risk of development in an area with potentially unstable soils and that he will advise, in writing, any prospective purchasers of the site of the slide potential of the area. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 Prior to final inspection, a covenant, running with the land, shall be executed by the owner. The City will file the covenant with King County, The covenant shall include those items listed in 18.45.080(e)(5)(E). In the case of this project, we also require a letter on file from Washington State Department of Transportation stating that they have also reviewed plans and specifications and understand the risks associated with project development. The letters we have received to date from WSDOT will suffice for this requirement. Once items 1,2 and 3 are submitted to found to be satisfactory, the Planning Division will sign off on the building permits and pass them on to Public Works for their review. If you have any questions, please give me a call at 431 -3661. Sincerely, R14 &ffi-tx Diana Painter Associate Planner cc Howard Turner Steve Lancaster Jack Pace •b' /iibi96 =ta Washiington State TI' Department of Transportation Date: July.18, 995 From: T. M. Allen/R.. E. Kimmerling OSC Materials Laboratory, 47365 Geotecluzical Services Branch ! Phone: 360 -586 -7659 (FAX 360 -586 -4611) To: R. I. Bennion P- 3/1'arkway, L.L.C. 8001!ifth Avenue, Suite 3700 Seattle, WA 98104 1 We have reviewed the re- design of pile 22 as submitted by GeoEngine reconfiguration of the wall appears geometry is consistent with the desi if you have questions or require Kinunerling at 360 -586 -7659. { TMA :rek • 2 u•I PIFi I CK 1 1-4L6 'LHE REK cc: Ron Cameron, City of Tukwila Bert Pschuuder, GeoEngineers Post -It• Fax Note 7671 Subject: P e segment of s dated July 1 ppropriate so 1 n assumption er information To Rem/ r.ffrwieO & Co./Dopler,. 0 / (% (i)% Phone 11 �FaxM 2O 11/- 366S Gv Memprandum 1 . RECEIVED JUL 181995 I TUKWILA PUBLIC WORKS kway Place Retaining Wall' 11 Re- design South of,Pile 22 • ie subject wall south or soldier 1995. ;The proposed ng as the final backslope f'3H:1V maximum. please contact Robert Date. /��� /G$ gaQO.� Froth es Xi:erner-/.' g n l Phon. NZO "OP'. 74SI/ Fas M 36 `".761 -F City of Tukwila John W Rants, Mayor Department of Community Development `,.:°June 64 1995:: <, : Mr. Roy Bennion Park Place Associates 800 Fifth Avenue Suite 3700 Seattle, Washington 98104 Steve Lancaster, Director Dear Roy: This is to remind you that we need a letter from WSDOT confirming that they have no issues with the design of the retaining wall on the Parkway Place project before we can issue the building permit for the wall and land altering permit for grading the hillside. Please note that WSDOT must have the current copy of plans and specifications that have preliminary approval by Tukwila's Department of Public Works, along with associated geotechnical materials, in order to make this determination. If you have any questions, please contact Ron Cameron or Joanna Spencer at 433 -0179. Sincerely, Diana Painter Associate Planner cc Ron Cameron Joanna Spencer Duane Griffin Jack Pace 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 41313665 Addendum to Report • - Geotechnical Engineering ,Services • Proposed Park Place • 17501 Southcenter Parkway Tukwila, Washington, • :March 6, 1995. ' �.. • G e o.E n g'i n e e r. s• PERMIT CENTER File No: 3944-003=801 Geo O Engineers Park Place Partners 800 Fifth Avenue, Suite 3700 Seattle, Washington 98104 -3122 Attention: Mr. Roy Bennion March 6, 1995 Geotechnical, Geoenvironmental and Geologic Services Addendum to Report Geotechnical Engineering Services Proposed Park Place 17501 Southcenter Parkway Tukwila, Washington GEI File No. 3944 - 003 -R01 INTRODUCTION This letter is an addendum to our "Report, of Geotechnical Engineering Services," dated November 10, 1994, for this project. The information in this letter is supplemental to and, in some cases, updates the information presented in our November 10 report. In any instances where our recommendations have been modified from those presented previously, the recommendations in this letter supersede those in our report. The primary purpose of this letter is to present an expanded scenario of the demolition and various phases of construction which involve significant earthwork activities. These phases are addressed in the following paragraphs. BUILDING DEMOLITION The existing nine -story building will be demolished and the structural elements crushed for subsequent use as select fill. Prior to demolition of the structural frame, all finishing materials such as carpet, floor tile, sheetrock, etc. will be removed. The portions of the structure which will be crushed for use as fill will be limited to concrete, brick and glass. The primary elements of the demolition, as they relate to site preparation and reuse of materials are described below. • Detnolition of the building columns, shear walls and interior walls down to the basement floor slab level will be accomplished throughout the building area. Removal of perimeter GeoEngineers, Inc. 8410 154th Avenue N.E. Redmond, WA 98052 'telephone (206) 861-6000 Fax (206) 861 -6050 Panted on recycled paper Park Place Partners March 6, 1995 Page 2 basement walls down to at least 5 feet below the base of any wall or column foundation locations for the new building will be accomplished. In other areas, the existing basement walls will be cut down to permit at least two feet of structural fill between the top of the remaining wall sections and the bottom of the new floor slab. • Remove the resulting demolition rubble from the basement area and process by crushing to 11/2-inch minus. The processed material will have the characteristics of a sand and gravel mixture with a fines content of about five to ten percent. The material will be stockpiled on -site until needed for use in select portions of the structural fill. Standard erosion and sediment control measures will be used to contain any migration of fines from the pile. A silt fence will be installed and maintained to accomplish this sediment control. • Mechanically break the basement floor slab in pieces with a maximum dimension of about 24 inches. Leave broken slab in place. • Maintain and operate existing dewatering well during and following demolition work and until backfilling of basement area is completed to the level of the existing surrounding grade. UTILITY (RELOCATED STORM DRAIN) INSTALLATION The 48 -inch storm drain which is presently aligned between the existing building and the toe of the slope to the west will be rerouted to an alignment to the east of the new building (building "B /C /D "). A new connection to the 66 -inch diameter pipe which traverses the site to the south of the existing building will be made. Normal construction techniques will apply to the installation of the new 48 -inch pipe. Geotechnical elements of installation are as follows. • Place bedding around all sides of pipes as recommended in our November 10, 1994 report. • Glacial soils excavated from trench can be used as backfill over the pipe provided that prevailing weather conditions are favorable for placement and compaction, that no standing water is present in the trench, and that the soil can be properly moisture- conditioned for compaction. • Alluvial soils (i.e., soft silt, peat and sandy silts) excavated from the trench should not be used as structural backfill but can be used in landscaped areas. Excess material of this type will need to be wasted off site. RETAINING WALL EXCAVATION Installation of the retaining wall along the west side of the construction area will proceed as soon as demolition of the building is essentially complete. The soil excavated from the hillside as the wall is installed will be used as structural fill in grading the site within the limits described in our November 10, 1994 report and below. • Glacial soils excavated from toe of slope as the retaining wall is constructed can be used as structural fill to raise the grade in the basement area and for building pads, provided that • e o E n g i n e e r s File No. 3944- 003 -RO1 Park Place Partners March 6, 1995 Page 3 prevailing weather conditions are favorable for placement and compaction, that the soil is not placed in areas where standing water is present, that the soil can be properly moisture - conditioned for compaction, and that the completed fill is properly protected from saturation and subsequent softening during wet weather. • If soils excavated from hillside cannot be effectively and efficiently moisture conditioned, stabilization using fly ash, kiln dust or portland cement should be accomplished to achieve satisfactory compaction and maintain the subsequent stability of structural fills. If weather conditions are too adverse to allow either moisture conditioning or stabilization treatment of these soils for compaction, it could become necessary to remove this soil from the site and import granular fill with a low enough fines content to achieve the specified compaction criteria. RETAINING WALL CONSTRUCTION Monitoring of construction of the permanent retaining wall will be provided by GeoEngineers, Inc. The nature of these services will be as follows: • Drilling operations for the soldier piles will be monitored to observe and maintain a record of the soils being penetrated and to provide consultation on modifications should the soil conditions encountered vary from those revealed in the borings drilled near the wall al ignment. • Periodic examinations of the soils exposed as the slope is cut back will be made before shotcrete is placed. • We will monitor the proof and performance testing of all tieback anchors for conformance with deflection and load carrying criteria. BUILDING "A" FOOTINGS AND FILL PAD For the most part, the footprint of building "A" is expected to be underlain by glacially consolidated soil which was exposed when the adjoining hillside was cut back to the present configuration in the 1960s. • Support all column and wall footings on hard silt or on compacted structural fill extending down to hard silt. It may be necessary to excavate loose or soft existing fill or alluvial soils in localized areas to accomplish this. Use crushed building rubble or imported clean granular soil as structural fill below footing grades in these areas. • Use crushed building debris or free - draining fill material as the capillary break, base course layer on which the floor slab will be constructed. • Remainder of any structural fill required for the building "A" pad can consist of on -site glacial soils, with the same provisions for use, placement, and compaction of these soils as discussed above and. in our November 10, 1994 report. G e o E n g i n e e r s File No. 3944- 003 -ROl Park Place Partners March 6, 1995 Page 4 BUILDING "B /C /D" BASEMENT AREA, FILL PAD AND FOOTINGS The majority of the footprint of this structure will be located over an area of glacially consolidated soils which were exposed when the hillside slope to the west was cut back in the 1960s. A zone of alluvially deposited soils may be encountered at the southerly end of the building area and along the east building wall near the north end. If these conditions are encountered, the alluvial soils are to be excavated and replaced with structural fill as described below. This fill should consist of either crushed building debris or imported clean sand and gravel compacted to at least 95 percent (ASTM D- 1557). Other elements of the earthwork procedures for this structure are as follows: • The existing dewatering well on the northwesterly side of the present building is to be kept operating until the basement area fill is brought to a grade even with the general surrounding area (about Elevation 30). • Initial filling in the basement area shall consist of placing and compacting, in lifts not exceeding 10 inches loose thickness, at least 18 inches of crushed building rubble or clean (less than five (5) percent fines) granular soil directly on the broken basement slab. • The remainder of basement area fill, with the exception of fill directly below footings, can consist of on -site glacial soils excavated from the hillside during retaining wall construction, again with the provisions described above for use of these soils. Place and compact this soil in layers to the criteria recommended in our November 10, 1994 report for structural fill. • At column and wall footing locations within the area of the existing basement, place and thoroughly compact crushed building rubble to provide a supporting zone extending a minimum of two (2) feet below footing grade. If there is an insufficient quantity of processed debris, imported clean sand and gravel should be used for this zone. This fill is to be placed in layers not exceeding 10 inches in loose thickness. These zones of crushed building rubble or granular fill are to extend two feet beyond the edges of footings. • Some column and wall footings will be located over the existing 48 -inch diameter storm drain which is to be abandoned in- place. Where column footings will be located within an area defined by a line drawn upward at a slope of 1H:1V from the edges of the pipe starting at the invert elevation, we recommend that the pipe in this area either be removed and the resulting excavation backfilled with structural fill meeting the requirements presented in our November 10, 1994 report or the section of pipe within an area defined by a 1H: I V slope drawn downward from the edges of the footing footprint be filled with grout. At locations where the pipe underlies the wall footing alignment, either of the above treatments can be used. Alternatively, the pipe can be spanned by extending a section of the wall footing on each side of the pipe down so that the bottom of footing grade lies below a line drawn upward at a slope of 1H:1V from the invert of the pipe. The GeoEngineers File No. 3944-003-R01 Park Place Partners March 6, 1995 Page 5 intervening distance between these two deepened footings would then be spanned with a grade beam. • Support all footings for building "B /C /D" (outside of the filled basement) on undisturbed native glacial soils or on a zone of compacted crushed building rubble or imported clean granular structural fill in any areas where alluvial soils are encountered at footing grades. The alluvial soils are to be excavated down to the surface of the underlying more competent soils before placing the crushed rubble or clean granular fill. The lateral extent of the zone of fill is to be as described for building A. • Use a layer of 6 inches of crushed building debris or free- draining granular soil as base course and capillary break for support of all floor slabs. • Remainder of pad for building "B /C /D" can consist of compacted on -site glacial soils with same provisions as above. FILL TESTING Sufficient monitoring and testing of the earthwork activities is an integral part of the geotechnical engineering services for a project such as this. These services will be directed to assessing the extent to which conditions encountered are consistent with those revealed by the explorations which have been completed and provide an opportunity to modify procedures and /or recommendations to the extent that this may be appropriate if changed conditions are encountered. The basic components of our activities related to fill placement on the Park Place project will include: • Compaction of crushed building rubble will be evaluated on the basis of visual observation of the behavior of the material as it is being compacted. • Compaction of native on -site borrow and imported pit run fill soil will be evaluated on the basis of visual observation, probing and nuclear gauge moisture and density tests on the insitu fill. • Observations and testing will be accomplished by a representative of GeoEngineers, Inc. on a regular basis during earthwork, utility installation and subgrade /subbase preparations. The frequency of site visits will be dependent on the contractor's rate of progress and will be coordinated with other aspects of the project which we will be monitoring. OTHER SITE WORK GENERAL Additional elements of work that apply to the site in general include the disposition of asphalt concrete pavement in building areas where fill will be placed to raise the grade, general stabilization of structural fills comprised of the on -site borrow to minimize disturbance by construction activities, and a modification of pavement design criteria in those areas where fill stabilization has been done. These are addressed in the following paragraphs. • e o E n g i n e e r s File No. 3944-003 -R01 Park Place Partners March 6, 1995 Page 6 ASPHALT CONCRETE LEFT IN PLACE Existing asphalt concrete pavement can be left in place in the new building areas if its presence will not interfere with installation of footings and utilities and provided that it will be covered by at least 1 foot of structural fill and base course beneath the finished floor slab. All paving left in place is to be broken into relatively small pieces (less than 24 -inch maximum dimension) as necessary to promote drainage. Asphalt concrete pavement that will be removed for construction of new facilities can be recycled for use in the lower portions of structural fill pads, provided that it is broken into pieces that are less than 4 inches in maximum dimension and that it is mixed with sufficient imported or on -site soil so that no open voids are left when placed as fill. SURFICIAL STABILIZATION OF STRUCTURAL FILLS Structural fills of the native silty soils excavated from the adjacent slope will be subject to disturbance if left exposed to rainfall, particularly if subjected to construction traffic. To minimize this impact, we recommend that the surface of such fills be stabilized with portland cement. Stabilization is to be achieved by spreading portland cement at a rate of 10 pounds per square foot, thoroughly and uniformly mixing the cement with the native soils by tilling to a depth of not less than 9 or more than 12 inches, and compacting this layer to the required density. This stabilization should be done by placing the final loose layer of fill, adding the cement and tilling before this layer is compacted rather than completing the fill and reworking the upper portion. The finished surface should be graded to a uniform smooth surface with sufficient slope to prevent ponding in the area. Construction traffic on stabilized areas should be minimized. In areas where heavy traffic will be imposed on the stabilized fill, it may be necessary to place a protective layer of crushed rock or small (four -inch minus) quarry spall to support loads such as cranes, concrete trucks and similar equipment. PAVEMENT SECTION DESIGN The base course requirement in areas where fill stabilization has been accomplished as described above can be reduced to a thickness of no less than 3 inches. Minimum asphalt concrete thicknesses of 2 and 3 inches for areas of automobile and truck traffic, respectively, are still applicable. • O ■ G e o Engineers File No. .3944-003 -RO1 Park Place Partners March 6, 1995 Page 7 Separate closure reports summarizing the construction work described above will be prepared for the retaining wall installation and for the other aspects of site preparation and earthwork respectively upon completion of the these phases of the work. Yours very truly, GeoEngineers, Inc. Jack K. Tuttle, P.E. Principal JKT:wd Document ID: 3944003.ADN Two copies submitted cc: City of Tukwila Public Works 6300 Southcenter Blvd., Ste 100 Seattle, WA 98155 Attn: Mr. Duane Griffin Mr. Howard Turner, Architect (three copies) Turner & Associates 18420 - 24th Pl. NE Seattle, WA 98155 Mr. Jack R. Bennett 20206 72nd Ave. SE Kent, WA 98032 Bush, Roed, Hitchings 2009 Minor Ave. E Seattle, WA 98102 -3513 Attn: Mr. John Anderson Foushee Associates 3260 118th Ave. SE, Ste 1000 P.O. Box 3767 Bellevue, WA 98009 Attn: Mr. Jeff Foushee G e oE n g i n e e r s `EXPIRES /0 AL/ 17h File No. 3944 - 003 -R01 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 Attach 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 non project proposals: Non project 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 non project proposals, even though questions may be answered "does not apply." In addition, complete the supplemental sheet for non project actions (part D). For non project 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. Control No. Epic File No. Fee $225.00 Receipt No. NOV 1 0 1994 DEVELOPMENT ENVIRONMENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: Parkway Place Retail Center 2. Name of applicant: Shidler/West Finance Partners III 800 Fifth Ave Suite 3700 Seattle, WA 98104 -3122 3. Address and phone number of applicant and contact person: Turner & Associates 18420 28th P1. N.E. Seattle , WA 98155 Phone (206) 365 -7431 4. Date checklist prepared: November 10, 1994 5. Agency requesting Checklist: City of Tukwila 6. Proposed timing or schedule (including phasing, if applicable): Grading of the hillside, the building site and demolition of the existing building is anticipated to start in the early part of 1995, and the construction and ongoing site improvements could be complete by fall of 1995. Timing would depend on the City's review process. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No. The project would not be extended beyond the project site and is submitted as a "stand alone" retail use intended to meet the City of Tukwila development standards. However, it is expected that a proposal for tenant improvements for the buildings as retail stores will be filed as soon as leases are completed and tenant improvement plans are p1epm'e 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. - Preliminary Report for BAR review and drawings, dated 11/10/94, Bush Roed and Hitchings, Inc. -Report of Geotechnical Engineering Services, dated 11/10/94, GeoEngineers -Traffic Impact Study, dated 9/15/94, Transportation,Planning, and Engineering, Inc. - Midday Trip Generation Memo, dated 11/9/94, Transportation,Planning, and Engineering, Inc. - Sensitive Areas Study Report, dated 11/10/94, by Talasaea Consultants - Design Review Application and drawings, dated 9/15/94, revised 11/10/94 Turner & Associates. -Survey by Michael Chadwick -Tree permit and landscape drawings, dated 11/10/94, by Landplan, PS, Shawn Parsons - Letters re demolition, from R.W.Rhine, Inc, dated September 23 and November 7, 1994 -Phase II limit subsurface Investigation, by Envirobusiness, dated November 12, 1993 - Environmental baseline Assessment, by Arthur D Little, dated April 29, 1993 -Letter re Tree Permit, by Landplan, PS, Shawn Parsons, dated 11/10/94 -Letter re tree permit exception, by Roy Bennion, dated 11/10/94 -Title report and easement descriptions, Chicago title Co. — Release and quitclaim on railroad easement from Union Pacific dated November 1, 1994. 9. Do you know whether applications are pending for government approval of other proposals directly affecting the property covered by your proposal? If yes, explain. No. 10. List any government approvals or permits that will be needed for your proposal. Board of Architectural Review Approval Building and Rack Permits Demolition Permit Land Altering Permit Miscellaneous Public Works Permits, eg. hauling street use, water meter, etc. Tree Permit 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 here. The proposed retail outlet would house 4 retail stores where general retail merchandise is sold. A portion of the adjacent hillside is to be altered. See the attached architectural drawings for building sizes. See the attached studies for site size and characteristics. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed 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 applications related to this checklist 17501 Southcenter Parkway, Tukwila, WA See attached sheet Al for Legal Description. 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan map as environmentally sensitive? The project lies within sensitive areas. Class 3 slopes extend east to the toe of the hillside along the railroad bed and west to the western property line. A Class II wetland exists at the south end of the property, and a Type 2 Stream runs near the north boundary. See the attached report by Talasaea Consultants. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General • : = • tion of the site (circle one): hilly, eep slope , mountainous, other. rolling, b. What is the steepest slope on the site (approximate percent slope)? Steep scopes up to 1 3/4: 1 exists on site, and unstable slopes exist 3/4 of a mile away along the same hillside. The attached report by GeoEngineers identifies the hillside as stable, and therefore not requiring buffers. The attached report by Bush, Roed and Hitching describes the required erosion control measures proposed during construction. c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. Glacial and interglacial deposit underlie the site. See the attached report by GeoEngineers. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. The hillside is defined as stable, see the attached report by GeoEngineers. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. Between 8- 10,000 cyds of soil from the hillside are to be removed and placed as fill under the proposed building and paving on the level portions of the site. See the attached report and drawings by Bush, Roed and Hitchings and survey by Michael Chadwick f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Yes, soil erosion could occur in connection with the proposed development since a portion of the site will be stripped of building and asphalt during the construction phase and the hillside is being altered. Erosion could occur during rain and/or wind storms that occur during the construction phase of the project. To minimize this potential for soil erosion, site preparation techniques would include temporary detention ponds and filter fences to reduce the impact of water runoff on the surface soil. When construction has been completed landscaping will have been placed on all surfaces not covered with impervious materials. No significant erosion is expected. See the attached report and drawings by Bush, Roed and Hitchings, and survey by Michael Chadwick. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? 72.6 %, see the attached report and drawings by Bush, Roed and Hitching. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: The alterations to the hillside is to be accomplished with soldier piles. This process involves slope stabilization prior to earth removal and gradual removal of soil as lagging is installed. Erosion control measures can be integrated with the soldier pile construction to minimize soil runoff and sliding. See drawings and report by BR&H. Earthwork activities should be done during periods of dry or intermittently wet weather. Erosion and sedimentation controls such as interceptor swales, straw bale barriers, silt fences and straw mulch for temporary erosion protection of exposed soils should be applied during construction. Stabilized construction entrances and wash pads should be installed at the beginning of construction and maintained for the duration of the project. All erosion and sedimentation control measures shall be installed and maintained in accordance with City of Tukwila requirements. During periods of intermittent wet weather, care should be taken to cover moisture sensitive soils with granular fill. New buildings are being located in areas of the site less prone to settlement; however, an acceptable amount of compression is expected. See the attached report by GeoEngineers. 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 when the project is completed? If any, generally describe and give approximate quantities if known. 3. 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, salt- water, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. Watercourse 26 -1, a Type 2 stream exists on site. The watercourse flows from west to east and is open to the air at the west side of the site. It goes into a pipe and underground prior to coming close to the level portion of the site. A Type II wetland, primarily located off-site, is located in the southwest corner of the site adjacent to an abandoned railroad bed. No other wetland areas were found. See attached report by Talasaea Consultants. 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. Grading of the hillside and construction of the retaining structure will occur down hill and within 70' of steam 26 -1. Buffers and mitigations are discussed in the attached report by Talasae Consultants. 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. Not applicable. 4) Will the proposal require surface water withdrawals or diver- ? Give general description, purpose, and approximate quantities, if known. No. Storm water runoff from the site will be discharged at the existing locations. 5) Does the proposal lie within a 100 -year flood plain? If so, note location on the site plan. Not Applicable 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and antici- pated volume of discharge. No, see the attached report and drawings by BR&H. Development of the site, as proposed, would not result in any significant impacts to existing air quality. The primary impacts from development of the purposed project are related to construction activities and future vehicle traffic. Dust generated from grading, demolition, and construction activity would be a temporary nuisance in the general area. Grading of the hillside will occur gradually in the method described in the attached report by GeoEngineers. Dust will effect the hillside, wetland, and stream areas for a short time. The process is expected to take a month. Demolition of the building will occur in the method described in the attached letters from Rhine, Inc. b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. No. .c. Proposed measures to reduce or control emissions or other impacts to air, if any: Transport of materials on local streets should be controlled to minimize congestion during peak travel times. This would minimize secondary air quality impacts caused by reduced travel times. Dust produced by construction and demolition can be reduced by using a number of techniques. Areas of exposed soils such as storage yards could be sprayed with water, oils, or chemical dust suppressants. Areas that might be exposed for prolonged periods of time should be covered with suitable ground cover to prevent wind erosion. Soil carried out of the construction area by trucks could be minimized by: use of a sawdust mat as a transition zone from the construction site; wheel washing; washing or brushing truck undercarriages; and covering dusty truck loads. For soils that do escape the constructions site on trucks, a daily cleaning program for truck routes would help minimize dust. Dust from the demolition of the building and grading of the hillside is minimized by the use of fog nozzles and misting devices as discussed in the attached letter from Rhine, Inc. A large proportion of the demolished building is to be left on site and used as fill material ( +/- 20,000 cyds), lessening the impact on offsite roads. Salvage of metals will be the major cause of trucking trips ( appox. 100) offsite. The entire demolition process is expect to take two months. b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. no, see the attached report and drawings by BR&H. 2) Describe waste materials that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemi- cals:; 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. See the attached report by BR&H. c. Water runoff (including storm water) : 1) Describe the source of runoff (including storm water) and the 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 the attached report and drawings by BR&H. 2) Could waste materials enter ground or surface waters? If so, generally describe. No, see the attached report and drawings by BR&H. d.Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: Oil water separators are being added to the storm system. See the attached report and drawings by BR&H. 4. Plants a. Check or circle types of vegetation found on the site: ✓ deciduous tree: alder, maple, aspen, other evergreen tree: fir, cedar, pine, other shrubs grass _ pasture crop or grain 7 wet soil plants: cattail, buttercup, bullrush, _ skunk cabbage, other _ water plants: water lily, eelgrass, milfoil, other types of vegetation b. What kind and amount of vegetation will be removed or altered? Small areas of landscaping located near the existing building or at the new building will be replaced by similar materials in similar quantities in adjacent new landscape planters. Vegetation on the sloped hillside behind the proposed retail building will be removed during the construction of the retaining structure, and replaced per the city's tree ordinance, see attached landscape drawings and report by Talasaea Consultants. c. List threatened or endangered species known to be on or near the site. None known. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: See attached landscape drawings and report by Talasaea consultants. 5. 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: (haw eron, eagle, . s ngbir a , other: mammals: deer, bear, elk, . • er, other: fish: bass, salmon, trout, herring, shellfish, other: b. List any threatened or endangered species known to be on or near the site. None known. c. Is the site part of a migration route? If so, explain. No birds are known to use the site as part of a migratory pattern. d. Proposed measures to preserve or enhance wildlife, if any: None. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc Electrical energy would be used for lighting and power for HVAC, refrigeration, and miscellaneous power equipment. Some heating will be reclaimed heat from refrigeration compressors. Supplemental energy for heat will be natural gas. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No. 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: For the retail portions of the building , energy conservation would consist of an insulated building envelope, HVAC with heat recovery features, automatic energy management system, airlock entrances, energy efficient light fixtures, and minimal use of glass. The State of Washington has adopted model conservation standards for new commercial buildings. Provided the City of Tukwila has adopted these standards, or has no standards conflicting there within, the future development would be consistent with these model standards. 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, des- cribe. No special environmental hazards are known to exist on the site besides asbestos in the floor tiles of the existing building. See attached reports by Arthur D Little and Envirobusiness and for abatement. The new retail tenants proposed at this time use no solvents and chemicals which are considered hazardous. 1) Describe special emergency services that might be required. Fire, police, and ambulance services would be required on a basis consistent with any four commercial retail stores totaling 154,300 square feet . No special services would be required. 2) Proposed measures to reduce or control environmental health hazards, if any: Not Applicable b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Traffic from adjacent streets may be heard from the interior of the site but will not affect the commercial operations proposed. 2) What types and levels of noise would be created by or assoc- ciated with the project on a short-term or long -term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. During demolition, noise levels will be higher than normally experienced on a construction site due to the crushing & recycling of the existing 9 story office building. The demolition phase is expected to last 2 months. Sources of noise identified for the development and operation of the retail project are as follows: construction related noise for approximately throe months from 7:00 am to 7:00 pm, six days per week; normal traffic generated noise associated with a commercial retail store and warehouse operation seven days per week; including several large truck deliveries per day. 3) Proposed measures to reduce or control noise impacts, if any: During demolition, noise will be controlled by careful placement of crushing and compacting equipment away from the public right of way and adjacent buildings. Noisy demolition will be accomplished only during business hours 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site of the proposed retail project is currently occupied by a 216,000 square foot office building . The surrounding area is generally developed with a mixture of light industrial and retail uses. b. Has the site been used for agriculture? If so, describe. No. Not in the recent past. c. Describe any structures on the site. A 216,000 square foot nine story office building now occupies the site. d. Will any structures be demolished? If so, what? The office building will be demolished. e. What is the current zoning classification of the site? The current zoning classification of the site is C2 Regional Retail. The proposed uses are allowed outright. f. What is the current comprehensive plan designation of the site? Retail g. If applicable- what is the current shoreline master program desig- nation of the site? Not applicable as the site is located more than 200' from the Green River. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. There are environmentally sensitive areas on site. including steep slopes, a wetland, and a stream. See the attached report by Talasaea Consultants. i. Approximately how many people would reside or work in the completed project? 100 workers. j. Approximately how many people would the completed project displace? The office building is currently vacant. When occupied, 2200 workers. k. Proposed measures to avoid or reduce displacement impacts, if any: Not applicable. L Proposed measures to ensure the proposal is compatible with exist- ing and projected land uses and plans, if any: The proposed is a concrete tilt -up structure that is similar in size, design, and scale of the other industrial, warehouse, and commercial buildings north, south, east, and west of the site. The proposed structure would be setback from Southcenter Parkway. The type of use proposed is also consistent with land uses adjacent to the site and in the surrounding area. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low- income housing? Not applicable. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low- income housing. Not applicable. c. Proposed measures to reduce or control housing impacts, if any: Not applicable. 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? The entry portions of building would be 48 feet in height. The remaining building elevations of the proposed structure would be approximately 31 feet in height. The principle exterior building material would be pre -cast concrete tilt -up panels with a series of offsets and entries built out of stucco. See the attached architectural drawings by Turner & Associates. A 5' - 30" high concrete retaining wall is proposed against the hillside. b. What views in the immediate vicinity would be altered or ob- structed? The view of the lower portion of the hillside from Southcenter Parkway will be more blocked in part by the new building. Other views are not being altered A 25' tall retaining wall against the hillside will be largely hidden by the building. c. Proposed measures to reduce or control aesthetic impacts, if any: A landscaping/sidewalk strip along the public right of way, interior parking lot landscaping, and perimeter landscaping consisting of trees, shrubs and ground cover are proposed. The proposed retaining wall is to be covered with landscaping & is almost totally hidden,by the proposed building 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Exterior lighting for the improvements resulting from the proposed bulk retail development would consist of wall lighting, parking lot lighting with non -glare fixtures, and signage. Any glare that may occur would happen at night. b. Could light or glare from the finished project be a safety hazard or interfere with views? No safety hazards from lighting would occur. c. What existing off -site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: All outdoor lighting would be shielded and directed downward to minimize potential intrusion on neighboring properties. 12. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? No recreational facilities are in the vicinity of the project site. b. Would the proposed project displace any existing recreational uses If so, describe. No. c. Proposed measures to reduce or control impacts on recreation, in- cluding recreation opportunities to be provided by the project or applicant, if any: None. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. None. b. Generally describe any landinarks or evidence of historic, arch - eaeological, scientific, or cultural importance known to be on or next to the site. Not applicable. c. Proposed measures to reduce or control impacts, if any: Mitigation measures are not required. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. Southcenter Parkway runs north south adjacent to the site. See attached traffic report by TP &E & attached site plans. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Meto bus routes stop on Southcenter Parkway, but not in front of property. c. How many parking spaces would the completed project have? How many would the project eliminate? The proposal includes 754 stalls,some of them compact. d. Will the proposal require any new roads or streets, or improve- ments to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). No, see attached traffic report. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. The proposal would not require the use of water, rail, or air transportation to provide goods and services to the site. f. How many vehicular trips per day would be generated by the com- pleted project? If known, indicate when peak volumes would occur. No new trips per day or during the AM,Noon, or PM peaks are expected See attached traffic report by TP &E. g. Proposed measures to reduce or control transportation impacts, if any: No mitigations are proposed. See attached traffic report. 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. The similarity in the proposed uses in the area indicate that there will be little increase. The site should experience a decrease from the prior use. b. Proposed measures to reduce or control direct impacts on public services, if any. No mitigation is required. 16. Utilities a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other. b. Describe the utilities that are proposed for the project, the util- ity providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Sewer: City of Tukwila Water: City of Tukwila Telephone: GTNW Power: Puget Sound Power and Light 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: Date Resubmitted: 11/10/94 APE VICTOR H BISHOP P E . President DAVID H ENGER. P E . Vice President TRANSPORTATION PLANNING & ENGINEERING, INC. Mr Roy Bennion 800 5th Ave. Suite 3700 Seattle, WA 98104 RE: Parkway Place Boeing Site Midday Trip Generation Dear Mr. Bennion: 2101 - 112th AVENUE N.E., SUITE 110 - BELLEVUE. WASHINGTON 98004 TELEPHONE (206) 455 -5320 FACSIMILE (206) 453 -7180 November 9, 1994 tant ' 5 1994 li4'r . DEVEL.Oi ='i> E:e'.r .l. Per your request we are pleased to present this letter identifying the midday trip generation for the .proposed 167,500 sq. ft. retail project. The Parkway Place Trip Generation Study prepared by us dated September 15, 1994, identified that during the AM and PM peak hours and on an average daily basis the proposed retail project will generate less traffic than the Boeing Office building did. According to Table 3 (attached), Page 1232, in the Institute of Transportation Engineers Trip Generation, 5th Edition retail activities occur between 10:00 A.M. and 10:00 P.M. with the peak eight hours occurring between 12:00 P.M. and 8:00 P.M. Of these eight hours the highest peak occurs during the 5:00 - 6:00 P.M. time period and the second highest during the 12:00 - 1:00 P.M. time period. According to Table 3, out of the 4,792 average weekday driveway trips 426 (8.9 %) of them occur during the P.M. peak hour (5:00 - 6:00 P.M.) and 417 (8.7 %) occur during the noon peak hour (12:00 - 1:00 P.M.). The Trip Generation does not contain specific hourly data for office trip generation. However, we believe that a sizeable number of the office employees choose to eat out or run noon time errands, thus generating significant traffic volumes. The Boeing office project employed 2,227 employees. If just 10% of these employees were to eat out or run errands at lunch, they would generate 445 trips, which is higher than the noontime retail project generated trips. As identified on page 3, second paragraph•of the Parkway Place Trip Generation Study letter additional retail activity is not likely to generate substantial new trips to the area. This is due to the fact that shoppers are already in the area and tend to shop at multiple centers, thus adding driveway trips but not new trips to the system. T0816A.94 Mr Roy Bennion November 9, 1994 Page - 2 - APE In conclusion a retail project in an area built up with other retailing services will have substantially Tess traffic impacts than the Boeing Office building which employed 2,227 employees. If you have any questions, please call me. MJJ:es Very truly yours, TRANSPORTATION PLANNING & ENGINEERING, INC. Mark J. s, P.E. Project Manager ; Table 2 Hourly Variation in Shopping Center Traffic Under 100,000 Square Feet Gross Leasable Area Time Average Weekday° Average % of 24 Hour Entering Saturdayb % of 24 Hour Exiting % of 24 Hour Entering % of 24 Hour Exiting 10 -11 A.M. 7.6 6.5 6.8 5.8 11 -12 Noon 7.6 8.4 ,?, Oo 8.8 1"-),7 - • 8.9 12- 1 P.M. 7.6 (r 8.2 9 o 9.4 IA.'? y 8.8 1-2 P.M. 6.9 g . 7:5 ?. .CC 10.0 2a,I 2, 10.1 2 -3 P.M. 9.0 11' 7.8 J. yo 9.7 le, I (/c 8.4 3 -4 P.M. 9.6 3 9.5 7.5-C 10.3 Mil 9.6 4 -5 P.M. 9.7 Z 10.4 /o -osr- 10.7 i.`f- f 10.7 5 -6 P.M. 10.3 t 11.0 /0.NS'' 9.4 I6,1 (,, /c 8.7 6 -7 P.M. 7.4 7- 8.3 'z, 2(5- 7.3 IS,r,. q 8.3 7 -8 P.M. 5.4 5.3 5.0 5.7 8 -9 P.M. 4.2 4.3 3.2 3.9 9 -10 P.M. 1.9 1.8 2.0 3.3 a Source numbers - 95, 124; based on tour studies. b Source numbers - 95, 124; based on tour studies. Table 3 Hourly Variation in Shopping Center Traffic Over 300,000 Square Feet Gross Leasable Area Time Average Weekday' Average Saturdayb Average Sunday' % of 24 Hr. Entering % of 24 Hr. Exiting % of 24 Hr. Entering % of 24 Hr. Exiting % of 24 Hr. Entering % of 24 Hr. Exiting 10 -11 A.M. ' 7.5 3.7 1 • 8.3 4.3 3.5 1.7 11 -12 Noon 8.6 5.9 : 10.9 6.9 9.4 3.5 12- 1 P.M. 4s .0 9.5 2 7.9 11.9 8.9 15.3 6.3 1 -2 P.M. 8-0ys 8.7 q 8.2 12.5 10.4 17.3 11.0 2 -3 P.M. g•3 s' 7.9 s 8.8 12.4 12.0 16.4 14.4 3 -4 P.M. g-.3 0 7.7 t.; 8.9 11.2 12.9 13.8 16.2 4 -5 P.M. 8.6 S. 8.2 3 9.1 9.2 13.4 9.8 16.8 5 -6 P.M. -.50 8.3 i 9.5' 5.2 12.7 5.5 15.7 6 -7 P.M. `3•. `/S•" 7.8. '.7. 7.7 2.9 8.0 2.2 6.1 7 -8 P.M. '. . -vr 8.4 , ' 7.0 . 1.9 2.1 1.3 1.9 8 -9 P.M. 4.7 7.7 1.4 1.2 0.8 1.1 9 -10 P.M. 1.8 9.1 2.9 0.8 0.6 0.9 ° Source numbers - 48, 73, 88, 124; based on seven studies. b Source numbers - 73, 88; based on three studies. 'Source numbers - 88; based on two studies. Trip Generation, January 1991 . 1232 Institute of Transportation Engineers RECE VF_ I w v 1 0 1994 DEVELOPMENT PRELIMINARY REPORT FOR BAR REVIEW PARKWAY PLACE REDEVELOPMENT TUKWILA, WASHINGTON BUSH, ROED & HITCHINGS 2009 MINOR AVENUE EAST. SEATTLE, WA 98102 PHONE:(206) 323 -4144 CONTACT: JOHN E. ANDERSON, P.E. November 10, 1994 Parkway Place is a 15.54 acre site as delineated on the architect's site plan. The project is located along Southcenter Boulevard in Tukwila, Washington. Located on the site is a 9 story office building which was occupied by Boeing. The tenant has moved out of the facility and the owner is looking to find a more viable use for the property. This proposal would demolish the existing building and construct approximately 3.5 acres of retail space on the property. There are several existing utility lines and easements across the site. We have used an ALTA survey and topographic information prepared by Chadwick Surveying and Engineering to determine how the utility lines would be routed through the site under the new layout. A new section has been added to this report to discuss the exiting utilities in more detail. This section has been added in response to the City of Tukwila letter dated October 31, 1994. The existing site is generally flat. A steep slope rises on the west side of the property to Interstate 5. The slope is covered with trees and thick underbrush. A railroad easement is located along the toe of slope. It is my understanding that the railroad easement vacation process is nearly completed. The 9 story building is located approximately midway between the railroad easement and Southcenter Boulevard. The existing building has a footprint of approximately 24,981 square feet. The remainder of the site is covered by asphalt parking and landscaping. Detailed surface area coverage calculation have been prepared and are shown on page 4 of this report. Two other building share the existing parking and access points to Southcenter Boulevard. Each of the buildings are located on segregated parcels and have not been included in the area count for the Parkway Place project. These structures are to be remain after the completion of the shopping center. Some grading of the parking area between the two building may be necessary for the construction of the new retail building. Final design will also require coordination of utility connections for the sewer and water main relocation. This subject will be discussed in more detail in the new section of the report. Redevelopment of this site will include the construction of two retail buildings. A 32,370 square foot building in the southwest corner and a 133,143 square foot building along the western boundary of the slope. The 133,143 square foot building will cover the area occupied by the existing 9 story office building. Some of the existing utility lines serving the site will have to be routed around the new buildings. This includes extending a water main loop around the west side of the new buildings, relocation of an existing 48 inch storm pipe and routing the existing sanitary sewer main around the east side of the buildings. The new buildings have been located so that the existing 66 and 54 inch storm drainage pipes from the southern off -site areas do not have to be relocated. Existing parking areas will the retained to the greatest possible extent. Some additional parking will be gained along the west side of the 133,143 square foot building with the relinquishment of the railroad easement. The new building has been located further west than the existing 9 story building. This will require construction of a retaining wall along the western margin of the site plan. Discussions with the owner have included using a solder pile wall or a soil nailed wall. The advantage of using this type of retaining structure is that it can be constructed with minimal disturbance to the areas above the top of wall. There is a public storm drainage system servicing the site from Southcenter Boulevard. Storm water will be collected in catch basins and conveyed using underground pipe. Much of the existing storm system in the vicinity of the existing building will be abandon. The site has been graded so that finished grade elevations around the new buildings are higher than the existing grade. Therefore the storm water will sheet flow to the existing catch basins located in the eastern parking areas. Loading docks on the western side of the buildings are the only locations where a new storm collection system will have to be installed. The proposed site plan reduces the net parking area by approximately 1.5 acres. Since the area subject to vehicular traffic will be reduce, there should be a corresponding improvement in storm water quality discharged to the downstream system. Oil /water separator vaults with coalescing chambers and high flow bypasses will also be installed to improve water quality prior to discharge to the downstream system. The site is served by public sewer. Redevelopment of the site to a retail center will significantly reduce the sanitary sewer discharge. The 9 story office building contained approximately 214,600 square feet of floor space and supported a population of approximately 2,230 people. The proposed 165,513 square feet of retail space will reduce the sewer discharge by approximately 31,650 gpd based on the D.O.E. Table No. 2 for new system design. Therefore redevelopment of this site to a retail facility will benefit the existing sewer system. SURFACE AREA COVERAGE Existing site: 676,948 SF IMPERVIOUS ROOF AREA IMPERVIOUS A.C. AREA IMPERVIOUS RAIL AREA PERVIOUS LANDSCAPE PERVIOUS WEST SLOPE (15.54 AC) = 24,981 SF (0.57 AC) = 383,677 SF (8.81 AC) • 26,136 SF (0.6 AC) 88,807 SF (2.04 AC) • 153,347 SF (3.52 AC) Redeveloped site: 676,948 SF. (15. IMPERVIOUS ROOF AREA IMPERVIOUS A.C. AREA IMPERVIOUS RAIL AREA PERVIOUS LANDSCAPE PERVIOUS WEST SLOPE 54 AC) • 165,513 SF 318,344 SF • O AC = 57,967 SF 135,124 SF (3.80 AC) (7.31 AC) (0.0 AC) (1.33 AC) (3.10 AC) 3 ADDITIONAL UTILITY INFORMATION Storm Drainage System: There are two major drainage courses draining beneath the Interstate 5 and conveyed through the site. The most northerly course discharges from a 48 inch culvert approximately 70 feet west of the northwest property corner. At the discharge point, a concrete energy dissipator with "V" notched weirs on the bottom side has been installed. Storm water flows east from the discharge in a 15 foot wide grass lined ditch to a 48 inch concrete culvert located approximately 20 feet east of the northwest property corner. The grass lined ditch area has been classified as a Class 4 steam. All work related to the Parkway Place project will occur outside the stream area. There is a concrete box inlet with a heavy steel trash rack at the 48 inch intake. From this point the storm water is conveyed in the 48 inch culvert approximately 145 feet to a 45 degree bend in the line. The bend directs the flow in a southeasterly direction toward a manhole located within the drive lane of the Parkway Place parking lot. An 11 foot wide concrete spillway has been constructed above the 48 inch culvert between the intake and 45 degree bend. The spillway directs the overflow to 2 -30 inch CMP culvert inlets located at the edge of parking, approximately 60 feet north of the northwest property line. The overflow lines convey the storm water easterly to Southcenter Boulevard and then northward in the street system. Therefore, once the inlet capacity of the 48 inch culvert is exceeded, the flow is routed to a separate storm system. Storm water flow in the 48 inch culvert is turned southward at the most northern manhole. John Howard, with the City of Tukwila, opened the manhole structure for my observation. The manhole has a round lid at the asphalt paving surface which covers a locking lid on the pipe. It is my understanding that the locking lid is required because the 48 inch pipe flows under pressure during heavier rainfall events or when the river is at a higher elevation. At the time of my observation, there was approximately 6 inches of water flowing in the pipe. Stones with a diameter of approximately one foot were also observed at the bottom of the pipe. From the manhole the 48 inch pipe conveys the storm water approximately 850 south. The pipe is deflected 21 degrees two the west approximately 570 feet south of the manhole. Approximately 180 feet south of the bend, the pipe is deflected 64 degrees to the east. The 48 inch pipe then extends 90 feet where it connects to a 66 inch culvert. Connection to the 66 inch pipe is accomplished using a wye. The 66 inch culvert then conveys the storm water easterly to Southcenter Boulevard. The second off -site drainage course discharges from an arched culvert on the east side 1 -5 located near the southwest property corner. The discharge flows into a fenced pool area. The pool flows into a 54 inch culvert which conveys the storm water easterly. The culvert is located just south of the southwest property line. There is an asphalt maintenance road above the culvert between the Parkway Place parking lot and the pool area. The 54 inch pipe is connected to the 66 inch culvert which also conveys the storm water from the 48 inch pipe discussed above. It does not appear that any manholes exist along the 54 inch pipe between the pool and 66 inch pipe. 48" Storm Relocation: The existing 48 inch storm pipe will have to be abandon because the new buildings will be located over the line. The new line will be located approximately 30 west of the existing location. The only other gravity line on the west side of the project is a 12 inch sanitary sewer main. The sewer main will be relocated to the east side of the new building, and therefore will not present a problem. Since the new storm line will be located further west, the connection at the north end will be made at a higher elevation. The new pipe can therefore be installed with a greater slope than provided by the existing. This will increase the gravity flow capacity of the 48 inch pipe. The new line will be constructed so that access points do not exceed 400 feet. Details of the access point will have to be worked out with the city. It is anticipated that a bolt down lid, similar to the existing, will be provided. Relocation of the 48 inch pipe will not alter the basin characteristics. The new line will remain a conveyance system for off -site flows only. No catch basin for on -site drainage will be connected to the new line. Therefore drainage from the site will not enter the pipe during or after construction. The abandon section of 48 inch pipe will either be filled with control density backfill or dug up and crushed. Economics will determine which method of abandonment will used. This issue will be reviewed more closely during the preparation of construction documents. to Sanitary Sewer System: The sanitary sewer main enters the site from the south near the southeast property corner. In the southern driveway, the sewer main is turned west and extends approximately 675 feet to a manhole located west of the asphalt parking lot. The sewer then angles northward to the loading dock area on the west side of the existing 9 story building. The manhole for the building connection is approximately 17 feet deep. There is an electronic flap gate on the building service line to prevent sewer from flowing into the building line. From this manhole the sewer main .continues northward approximately 640 feet to a manhole located in the northwest corner of the site. This manhole also collects flows from areas north of the Parkway Place site. From the manhole in the northwest corner of the site, the flow is turned eastward toward Southcenter Boulevard. The sewer main crosses beneath Southcenter Boulevard and then turns northward. It appears the primary reason the sewer was extended to the west side of the Parkway site was to provide a future connection point for property to the west. Since the main was extended the longest possible route, it became relatively deep along the western side of the project. The existing 9 story building required a deep building sewer service to the basement and therefore the additional depth was justifiable. The new site plan locates a building over the existing sewer main. Therefore the sewer will have to be relocated. A deep sewer is not required since the new building will be slab on grade.. This allows a greater flexibility in determining a new location for the sewer main. Finished grades on the east side of the site are 3 to 4 feet lower than on the west side. Locating the sewer main on the east side of the new building would take advantage of the lower finished grades. A sewer main located on the east side of the building would extend a shorter distance than the existing line. The shorter distance between existing flow line grades means the new section will have a greater slope than the existing pipe. Finished grade elevations will be significantly higher for any developments west of the Parkway Place project. Therefore a deep sewer connection depth is not required for the future areas. A new sewer stub can be extended to the west property line at a shallower depth. It appears the logical location for the new sewer main is on the east . side of the new buildings. The existing sewer main will have to remain in operation during construction of the new main. This can be accomplished by setting a new manhole structure on the existing main at the lower connection point. The existing pipe will extend through the new structure and continue to convey the flow. From the manhole, new sewer pipe will be installed southward to the existing main. Anew manhole will be set over the existing main at the higher connection point. Again the existing pipe will extend through the new manhole conveying the flow to the existing downstream pipes. The new sewer. run will be tested and approved prior to routing the flows into them. Once approved, the existing pipe within the manhole will be removed and the manhole bottoms channeled to direct the flow into the new sewer pipe. Water Service: A dead end 10 inch water main currently serves the Parkway Place site. The dead end line also appears to be the only service for the adjacent properties on the north and south side of Parkway Place. The water main enters the site from Southcenter Boulevard, just north of the center driveway. The water main has a pressure of approximately 150 psi, and therefore fire flow is not in question. The water main will be looped around the new buildings. This is necessary to adequately provide the fire hydrant spacing. The existing dead end water main will have to be connected to another main so that the loop has two sources. This will allow sections of the main to be isolated for maintenance without shutting down the water supply for the entire system. A second feed will also be required by the fire marshal. The new connection could be made to the main in Southcenter Boulevard. It is my understanding that a water main has been extended to the west side of Southcenter Boulevard south of the Parkway Place project. This also maybe a location for a second connection. Viability of this connection will depend on the distance south and the willingness of the adjacent property owners to allow a water main extension across their property. The location of the second connection will be determined during the preparation of the construction documents. The connection to the Southcenter Boulevard main would require boring. Therefore we would like to pursue the connection to the main on the west side of the street first. Temporary Erosion Control and Grading: One of the first tasks will be the demolition of the existing building. It is my understanding that the building will be demolished using a crane and wrecking ball. This process will require a relatively small area for stock piling the material and moving the construction equipment around the existing structure. During this phase, most of the existing asphalt paving will be retained. An area will dedicated for stock piling the material. The area will be enclosed with filter fabric fence to prevent silt laden storm water run -off from entering the existing storm system. Since the material will consist of crushed brick and concrete, siltation should not be a significant problem. A wetland exists in the southwest corner, just outside the parking lot area. The wetland has been delineated by a wetland specialist and located by a field survey crew. Since the existing parking lot drains from west to east, storm water run -off control should not be a problem during construction. The new site plan has been design so that new paving will not extend beyond the existing pavement in the vicinity of the wetland. A filter fabric fence should be installed prior to starting demolition so that the wetland can be clearly identified. The filter fabric fence will also prevent silt laden storm water from entering the wetland during construction. The next phase will be intensive grading for the preparation of building pads and construction of the retaining wall along the western side of the project. The retaining wall will be constructed from the top -down. Therefore the slope above the wall will not have to be cut back for construction. This will help minimize the disturbance to the slope above the wall. Material excavated from the slope during the retaining wall construction will be placed directly on the building pads and compacted in lifts. There is an existing ditch along the western edge of paving which conveys the hillside drainage to the north and south. The section which drains to the south flows into the wetland. Construction of the retaining wall and building pads will destroy the existing ditch. An interceptor swale will be constructed at the top of wall to convey the hillside drainage north and south. The interceptor swale will prevent storm water from flowing over the top of wall during construction and after the wall is completed. The section of swale draining southward will be tied back into the wetland, preserving the existing wetland hydrology. Filter fabric fence will be installed along the eastern limit of clearing. An interceptor swale will be constructed along the western side of filter fence. The swale will convey storm water run -off from the disturbed areas to sediment traps. This system should provide adequate protection for the downstream system. Crushed material from the existing building will be used to cap the building pads and graded parking areas. The crushed material will provide a surface which is resistant to erosion. Other Best Management Practices will also be implemented to reduce the impacts to off -site areas. These include wetting the demolition materials being crushed and graded areas to reduce dust, installing filter fabric material in catch basin grates, sweeping parking lot and road surfaces, delineating limits of clearing on the plans and installation of a rock construction entrance. Site grade will be established to produce a balanced earthwork volume. This will help reduce truck traffic outside the project area during construction. These measures represent the minimum requirements which will be shown on the construction documents. Final Drainage System: The off -site drainage tightline system will retain the same function as the existing site. Relocation of the 48 inch pipe will not change the flow characteristics of the system. If the northern 48 inch pipe system inlet capacity is exceeded, then the storm water will follow the existing overflow route. The new building has been located so that the north face does not extend into the existing overflow route. If there is a failure of the overflow route, storm water will flow overland to the Southcenter Boulevard system. The building will not be flooded if this occurs. Buildings have also been located outside the overflow route for the southern 54 inch pipe system. If the inlet capacity of the 54 inch pipe is exceeded, or there is a failure, storm water will flow overland to the wetland area. This is the same route followed under the existing site plan. The building will not be flooded if this situation occurs. A swale will be constructed along the top of retaining wall at the western slope. From the retaining wall high point, the swale will convey storm water north and south along the top. At the point where the retaining wall is no longer required, the swales will be connected into the existing ditches. Therefore the existing drainage courses will be preserved. This is critical for the southern drainage course since it supplies water to the wetland. Drainage from the new parking lot will be collected by the existing catch basins. Underground pipe from the new catch basins at the loading docks will convey the storm water to the existing storm drainage system. The existing storm drainage system discharges untreated storm water directly into the Southcenter Boulevard system. Since this is no longer an acceptable practice, oil /water separation vaults with a coalescing chamber will be installed at the existing discharge points. This method of water quality improvement is widely accepted for existing storm system retrofit in urban areas. The water quality vaults will be sized for a 6 month -24 hour storm event according to Standards. Storm water flows greater event will be routed around the vault assures the oils and sediment trapped flushed to the downstream system. D.O.E. Storm Water Design than the 6 month -24 hour in a bypass system. This, within the vault are not proposed Parkway Place !. 1.75.01 Southcenter Parkway e, o E n g i n e- e_ r: s i l �' File'No:, 3944-0021-R01/111094 Geo ..: Engineers November 10, 1994 Mr. Roy Bennion 800 Fifth Avenue, Suite 3700 Seattle, Washington 98104 -3122 Dear Mr. Bennion: Geotechnical, Geoenvironmental and Geologic Services GeoEngineers, Inc. is pleased to submit three copies of our "Report of Geotechnical Engineering Services, Proposed Parkway Place, 17501 Southcenter Parkway, Tukwila, Washington." The scope of our services is described in our proposal dated October 20, 1994. Mr. Roy Bennion provided verbal authorization of our services on October 28, 1994. Preliminary information has been provided to you and other members of the design team as our findings were developed. We appreciate the opportunity to work with you on this project. If you have any questions regarding the contents of this report or need additional information, please contact us. We look forward to assisting you during the construction phase of this project. Yours very truly, ineers, Inc. UJ7 K. Tuttle, P.E. rincipal HRP:JKT:cros Document ID: 3944002.R cc: ✓Turner and Associates (three copies) 18420 - 24th Place N.E. Seattle, WA 98155 Attn: Mr. Howard Turner File No. 3944 - 002 -ROl GeoEngineers, Inc. 8410 154th Avenue N.E. Redmond, WA 98052 Telephone (206) 861 -6000 Fax (206) 861 -6050 k. CONTENTS Page No. INTRODUCTION 2 PROJECT DESCRIPTION 2 SCOPE OF SERVICES 2 SITE DESCRIPTION 4 SITE HISTORY 4 GEOLOGIC CONDITIONS 4 SURFACE CONDITIONS 5 SUBSURFACE CONDITIONS 6 Level Portion of Site 6 Hillside Portion of Site 7 CONCLUSIONS AND RECOMMENDATIONS 8 GENERAL 8 SITE PREPARATION AND EARTHWORK 8 FOUNDATION SUPPORT 11 FLOOR SLABS 12 SLOPE RETENTION 13 SLOPE STABILITY 15 SURFACE DRAINAGE 16 PAVEMENTS 16 UNDERGROUND UTILITIES 16 LIMITATIONS 17 FIGURES Figure No. Vicinity Map and Street Map 1 Site Plan 2 Generalized Subsurface Cross Section A -A' 3 APPENDICES Page No. Appendix A - Field Explorations and Laboratory Testing A -1 Field Explorations A -1 Laboratory Testing A -2 GeoEngineers I File No. 3944-002-R01/111094 CONTENTS (continued) APPENDIX A FIGURES Soil Classification System Key to Boring Log Symbols Logs of Borings Logs of Test Pits Moisture Content Data Gradation Curves Direct Shear Test Data Appendix B - Slope Stability Analysis Results Figure No. A -1 A -2 A -3 ... A -10 A -11 ... A -13 A -14 A -15 A -16 G e o E n g in ee r.s File No. 3944-002-R01/111094 REPORT GEOTECHNICAL ENGINEERING SERVICES PROPOSED PARKWAY PLACE 17501 SOUTHCENTER PARKWAY TUKWILA, WASHINGTON FOR MR. ROY BENNION INTRODUCTION This report presents the results of our geotechnical engineering services for the proposed Parkway Place development at 17501 Southcenter Parkway in Tukwila, Washington. The site location is shown on the Vicinity and Street Map, Figure 1. These services are a continuation of our involvement on the project, which includes geotechnical consultation services summarized in our letter dated September 15, 1994. PROJECT DESCRIPTION The planned project will create a retail store development similar in nature to other developments in the immediate area. This development will include the demolition of an existing nine -story office building and construction of four new buildings, three of which will be located in approximately the same area as the existing building. Three of the buildings (Buildings B, C and D) will be combined into a complex, while the fourth building (Building A) will be located in the southwest portion of the site, adjacent to an existing furniture store. The buildings will each be two stories in height, based on architectural plans prepared by Turner and Associates, Architects. Building A will measure roughly 187 feet by 166 feet, while the three building complex will measure roughly 590 feet long by 210 feet wide. The buildings will be located to avoid construction over weak, compressible soils encountered in previous explorations at the site. The existing nine -story office building will be demolished and the resulting rubble crushed to a gradation satisfactory for use as structural fill in the depression remaining after demolition and for support of building floor slabs. This will eliminate a major waste disposal problem. A truck access and fire lane will be located along the west side of all four buildings. This will require excavation into the adjacent hillside and construction of a retaining wall. Based on the most recent site plan made available to us, we understand that the wall will be up to 600 feet long and about 25 feet high. Other site improvements include modifications to the existing asphalt paved areas, and relocation of existing and installation of new utility lines. SCOPE OF SERVICES Our previous consultation addressed the general site history and subsurface conditions based on the results of previous explorations by others on and in the immediate vicinity of the site, G e o E n g i n e e r s 2 File No. 3944- 002- R01/111094 personal experience of our staff during the design and construction of the existing office building, and consultation for The Boeing Company as tenants of this building regarding dewatering requirements to maintain a dry basement level. The results of this consultation were presented in our September 15, 1994 letter. The services provided for this current study are intended to develop sufficient additional subsurface information for use in geotechnical design of the various elements of the project. The major portion of our study is directed to defining subsurface conditions in the vicinity of the proposed retaining wall and accomplishing analyses to define design parameters for the retaining wall. Supporting analytical information is included in this report to facilitate the review of our conclusions and recommendations by the city of Tukwila and WSDOT (Washington State Department of Transportation). Our specific scope of services includes the following tasks: 1. Review available geotechnical information prepared for past development activity at the site and also by WSDOT for construction of the I -5 corridor at the top of the hillside. 2. Explore subsurface conditions in portions of the site not covered by previous explorations, including portions of the four building sites and along the general alignment of the retaining wall. A total of seven borings and three test pits were made. 3. Accomplish laboratory tests on representative samples obtained from the explorations, including moisture, dry density, gradation and strength tests. 4. Provide recommendations for site preparation and earthwork, including processing of building demolition debris for use as fill, use of on -site soils as structural fill, criteria for imported soils to be used as fill, fill placement and compaction criteria, and allowable temporary and permanent cut and fill slopes. 5. Develop recommendations for foundation support of the new buildings, including allowable bearing pressures, minimum footing sizes and embedment depths, settlement estimates, and subgrade preparation procedures 6. Provide recommendations for the retaining structure west of the three- building complex, including wall type, active and passive pressure values, backfill criteria and drainage requirements. 7. Evaluate the overall stability of the slope for static and seismic conditions after design and construction of the retaining wall in accordance with our recommendations. 8. Provide recommendations for site drainage, including control of seepage during retaining wall construction and surface drainage adjacent to buildings and in parking areas. 9. Present our findings, conclusions and recommendations, with supporting field and laboratory data, in a written report. 10. Attend design consultation meetings prior to starting our field exploration program and following submission of our report to assist in application of our recommendations and preparation of responses to reviewing agencies if and as appropriate. G e o E n g i n e e r s 3 File No. 3944-002 - 801/111094 SITE DESCRIPTION SITE HISTORY The site has been substantially modified from the natural terrain that existed prior to the mid- 1960s. The west wall of the Green River valley was cut back to the present configuration in the mid -1960s exposing glacially consolidated soils in the area of the existing nine -story building and in the area of the existing furniture store located just south of the site. The depth of cut exceeded 100 feet in portions of the site. This material was used as borrow for retail developments located on the east side of Southcenter Parkway. After extensive analysis of varying slope configurations for the reshaped hillside, a cut slope of 13/4 H:1 V (horizontal to vertical) was recommended and the slopes were graded to this inclination. The 30 years of satisfactory performance of these cut slopes indicates that the chosen slope configuration is appropriate. Construction of Interstate 5 also took place in the 1960s. The segment of freeway west of the site and north of the South 178th Street undercrossing involved construction of a significant cut through the east -west trending ridge and significant fill embankments over deep ravines flanking the north and south sides of this ridge. Large diameter storm drains extending down the axes of the these ravines were apparently constructed prior to placing the fill embankments. The regrading of the hillside in the vicinity of the site exposed competent glacially consolidated soils on which both the furniture store and the nine -story office building have been successfully supported on shallow spread foundations. The excavation for the office building extended below the static ground water table necessitating dewatering for foundation construction and to maintain a stable subgrade for the basement floor slab. Subsequent to building completion (which occurred sometime after 1979), it was necessary to install two permanent dewatering wells to maintain a dry basement slab since gravity flow in the slab underdrain system was not adequate. GEOLOGIC CONDITIONS The geologic conditions at the site are largely the result of deposition and erosion during and following the most recent episodes of glaciation in the Puget Sound region. Glacial and interglacial deposits underlying the hillside in the western portion of the site include primarily pre - Vashon fine- grained lacustrine deposits that were later overridden by several thousand feet of glacial ice. Geologic maps dating back to the early 1960s indicate that the hillside that existed prior to grading was underlain by kame terrace deposits that were left behind by glacial melt water flowing along the edge of the ice that filled the Green River valley near the end of the Vashon glaciation. These deposits apparently have been completely removed from the lower portion of the hillside which includes this property. The upper portion of the valley wall probably is underlain by glacial till, a very dense, unsorted deposit of silt, sand, gravel and cobbles. The glacial deposits possess high strength and low compressibility characteristics. GeoEngineers 4 File No. 3944-002-R01/111094 During early post - glacial time the area of the present Green River valley was a marine inlet, which was subsequently filled by sediment from the river. Throughout postglacial time the glacial deposits in the west valley wall have been subject to weathering and erosion, resulting in deposition of sediment at the base of the valley wall. The ravines which flank the hillside in the western portion of the site are examples of such erosional features. The deposits at the mouth of these ravines and in the eastern portion of the site include alluvial soils with generally high compressibility and low strength. Figure 2 shows the approximate limits of the compressible alluvial soils within the site. These soils generally include loose sand, soft silt and peat, although more competent alluvial soils, primarily medium dense sand, occur closer to the mouths of the ravines. Considerable change has occurred within and adjacent to the site within the past 30 years. These changes include the extensive grading of the hillside, placement of the fill embankments for Interstate 5 across the upper portions of the ravines and placement of general site fill over areas underlain by alluvial soils. The city of Tukwila geologic hazards maps designate the majority of the hillside as a Class 3 landslide hazard area. This designation includes all areas sloping more steeply than 40 percent. Class 4 areas, which include areas of known mappable landslide deposits, do not occur within or near the site. Also, the subsurface conditions approximately 3/4 mile north of the site where major instability of the slopes near the I- 405/1 -5 interchange was experienced do not occur at the subject site. SURFACE CONDITIONS The majority of the site is level and surfaced with asphalt concrete pavement. Ground surface elevations within the pavement area are generally between Elevation 30 and 35 feet (1929 NGVD datum). The existing nine -story office building occupies the central portion of the site. Numerous landscaped "islands" exist within the asphalt -paved areas. A satellite dish with related facilities is located on the south side of the nine -story building. An abandoned rail spur extends along the base of the hillside; this spur is depressed about 2 to 3 feet below general pavement grade. The hillside extends from the abandoned rail spur up to the end of an east -west trending ridge at the western property line. The hillside is generally inclined at about 1.75:1 (horizontal to vertical). From the westerly property line, the ridge extends about 300 feet to the edge of northbound Interstate 5. The crest of the ridge is at about Elevation 220 feet. A cut of about 10 feet was made through the ridge for the northbound lanes. The topographic form of the hillside can be described as pyramidal, with the east - facing side including the graded slope above the site flanked on both the north and south by the deep natural ravines. As described above, the ravines are crossed by extensive fill embankments placed for Interstate 5. The hillside facing the site includes at least two benches that are the result of grading. One bench is at approximate Elevation 50 to 55 feet, while the second bench is about 50 feet higher. These benches extend the full width of the slope. A third bench is located at about Elevation G e o E n g i n e e r s 5 File No. 3944- 002- R01/111094 140 feet, near the western property line; this bench is also probably the result of grading. Vegetation on the hillside consists primarily of deciduous trees with dense underbrush and scattered evergreen trees. Some of the deciduous trees are leaning in a downhill direction, which in a natural slope might be indicative of shallow soil creep. In our opinion, however, the trees are leaning primarily a result of seeking light rather than soil creep, since hard and dense soils underlie the slope at shallow depths. Numerous underground utilities exist within and near the site. Major storm drain lines carrying flow from the area of Interstate 5 extend down both ravines. These lines tie into a 48 -inch storm drain which extends in a north -south direction beneath the western portion of the future three - building complex. The storm drain turns to the east near the southwest corner of the proposed three- building complex and continues to the east outside of the south edge of the complex area. A 12 -inch sanitary sewer also exists in the same general location. Both of these lines will be relocated during project construction. Other utility lines include water, power and natural gas lines which serve the existing nine -story building. These lines approach the building from the east. SUBSURFACE CONDITIONS The subsurface conditions near the base of the hillside and in portions of the four building areas were explored by drilling seven borings and excavating three test pits at the locations shown in Figure 2. Also shown in Figure 2 are locations of previous explorations accomplished by others for various phases of past site development, including borings drilled for the nine -story building. A description of the field and laboratory testing programs along with the logs of our current explorations and boring A from a previous study are presented in Appendix A. We also reviewed available boring logs on file with WSDOT for the Interstate 5 corridor in the vicinity of the upper portion of the hillside. Subsurface conditions for the level portion and the hillside portion of the site are discussed separately below. Level Portion of Site Subsurface conditions in the vicinity of proposed building A consist of 1.5 to 2.5 inches of asphalt concrete pavement underlain by a 1- foot -thick layer of gravel with sand fill. The fill is underlain to a depth of 4.5 feet below the existing ground surface by medium stiff to stiff silt. Hard silt with scattered organic zones and very dense sand underlies the medium stiff to stiff silt. No ground water was encountered during the drilling of these two borings. Previous test pits excavated near the building location encountered similar soils at depth, although the original surficial soils were probably removed during initial site development. Slight ground water seepage was encountered in test pit 2 for a previous study at depths of 1, 9 and 11 feet below the former ground surface. Subsurface conditions within the proposed three - building complex area were evaluated primarily by reviewing the logs of previous borings and test pits in the vicinity and by drilling borings B -6 and B -7 to fill in gaps between the previous explorations. In general, the planned G e o E n g i n e e r s 6 File No. 3944 - 002- R01/111094 complex avoids the identified areas of weak, compressible alluvial soils indicated in Figure 2. Our recent borings indicate that the building footprint outside of the existing nine -story building is surfaced with 2 inches of asphalt concrete pavement and underlain by 1.5 to 3 feet of granular fill consisting primarily of medium dense silty sand and gravel fill. The fill possibly extends to a depth of 11 feet below the pavement in boring B -6. The previous borings for the nine -story building also encountered fill to depths ranging from 2 to over 10 feet below the former ground surface. The test pits excavated for a study accomplished in the mid -1970s indicate that dense sand and silty sand and hard silt underlie the three building complex at relatively shallow (within a few feet) of the ground surface that existed prior to initial filling of the site. These soils were encountered at depths of 11 and 7.5 feet in our current borings, respectively. The ground water level in the area of the existing building has been observed to be on the order of 8 feet below existing pavement grade, although there are apparently seasonal variations of a few feet due to fluctuations in the amount of recharge coming from the hillside to the west. Ground water seepage was also observed in the previous explorations in the vicinity of the three - building complex area; however, the placement of fill over the ground surface after these explorations were accomplished makes only a rough estimate of the depth to ground water in these areas possible. In general, the depth at which ground water was encountered in our current explorations appears to correlate with the 8 -foot depth noted above. Our current boring B -6 encountered ground water at a depth of 4.5 feet. Hillside Portion of Site Generalized subsurface conditions within the hillside are depicted in Figure 3. The soils which underlie the hillside consist primarily of strata of hard silt with varying amounts of sand and clay. As noted above, these strata have been overridden by glacial ice, probably on at least two occasions. Borings B -1, B -2 and B -3, along with the associated test pits TP -1, TP -2 and TP -3 encountered fairly uniform conditions. The combination of a test pit and a boring at each location on the lowest bench provided a stratigraphic record over a total vertical distance of about 70 feet, with a corresponding range of from 10 feet above the planned top of retaining wall to about 35 feet below the planned base of cut. The test pits encountered less than 1 foot of loose or soft surficial soil with organic matter. The majority of the soils encountered in the test pits and borings consist of silt, sandy silt and silt with clay, with occasional layers and lenses of silty sand and sand. Some of the upper 10 feet of silt underlying the slope exhibits some fractures which might be the result of stress relief following excavation of the original hillside within the last 30 years. Our observations of the samples obtained from the explorations indicates that no movement has taken place along these fractures The log of boring A drilled in 1964 indicates that the hard and dense glacial consolidated soils extended up to at least Elevation 150 feet in the hillside. This boring was located in an area where the hillside was cut to near the present level grade. No borings were apparently drilled G e o E n g i n e e r s 7 File No. 3944 - 002- R01/111094 within the Interstate 5 corridor where it crosses the east -west trending ridge above the hillside; however, nearby borings indicate that glacial till with a thickness on the order of a few tens of feet caps the upper portion of the valley wall in the general vicinity of the site, as indicated in Figure 3. Ground water was encountered in each of the three hillside borings during drilling and also measured a few days after drilling in piezometers installed in the borings. Observed and measured ground water levels ranged from 23 feet to 31 feet below the bench level. These levels generally correlate with the ground water level observed in the vicinity of the existing nine -story building. CONCLUSIONS AND RECOMMENDATIONS GENERAL We conclude that the site can be satisfactorily developed for the proposed retail buildings, provided that proper design and construction procedures are used to minimize the potential for destabilizing the hillside. The proposed buildings can be supported on shallow foundations bearing either on undisturbed hard or dense native soils, or on compacted structural fill. This fill can consist of crushed concrete, brick and glass created by demolition of the existing nine- story building. Some measures to control inflow of ground water into the depression resulting from demolition as it is being filled may be needed. Site preparation and earthwork should take place during periods of dry weather because of the moisture - sensitivity of the on -site soils, particularly if the soils excavated from the toe of the hillside are to be used as structural fill for the building pads. If these activities take place during wet weather, it might be necessary to use more imported granular soil instead of on -site soils for structural fill. Care should be taken during construction of the retaining wall to keep disturbance of the slope above the wall to a minimum. A detailed discussion of our recommendations for site preparation and earthwork, foundation and floor slab support, retaining wall design and construction, slope stability, drainage and other considerations is presented in the following sections. SITE PREPARATION AND EARTHWORK Demolition of the existing nine -story office building will result in a depression where the basement is now located. This depression will be filled to establish floor grades for the three - building complex. In addition, the depressed grade of the existing abandoned rail spur along the toe of the hillside will be raised. Present plans call for using crushed concrete, glass and brick from the existing building for portions of this fill. In our opinion, this is a feasible plan. It also might be desirable to break up the asphalt concrete from areas of pavement to be removed for use as fill. G e o E n g i n e e r s 8 File No. 3944- 002- R01/111094 Demolition of the building columns, shear walls and interior walls down to the basement floor slab level should be accomplished where necessary. Removal of perimeter basement walls might not be necessary at all locations; however, these should be removed along the alignment of new wall foundations or where individual column foundations would be located over an abandoned wall. In other areas, the existing basement walls should be cut down to permit placement of at least 2 feet of structural fill between the top of the remaining wall section and the bottom of the new floor slab. The existing basement floor slab should be broken or perforated by drilling 4- inch - diameter holes on about an 8 -foot grid to prevent water from ponding on the slab. The existing floor slab, if left in place, will provide a stable working surface for equipment working within the depression. We recommend that the demolition debris to be used as structural fill placed 2 feet or more below footings or floor slabs be crushed to a gradation of between 1 and 3 inches in size. This material should be placed in lifts not exceeding 12 inches in loose thickness and compacted to a dense, nonyielding state with a vibratory roller. This zone of debris fill should be capped with an additional 12- inch -thick layer of debris crushed to 1'44 inch minus to choke the voids in the underlying larger graded debris. This zone should be placed in two lifts of equal thickness and compacted as indicated above. The final layer of structural fill should consist of clean pit run sand and gravel which is placed and compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D -1557. Ground water will likely be encountered in the depression remaining after demolition. We recommend that ground water inflow into the depression be controlled during construction by pumping from a series of sumps placed around the perimeter of the depression. Existing asphalt concrete pavement can be left in place in new building areas, if its presence will not interfere with installation of footings and utilities and provided that it will be covered by at least 2 feet of structural fill and that it is broken into relatively small pieces (less than 1 foot maximum dimension) as necessary to promote drainage. Otherwise, the existing asphalt can be recycled for use in the lower portions of structural fill pads, provided that it is broken into pieces that are less than 4 inches in maximum dimension and that it is mixed with sufficient import or on -site fill soil so that no open voids are created. We understand that the segment of 48 -inch storm drain which underlies the western portion of the three- building complex will either be abandoned in place or removed and crushed in a manner similar to the existing building. If the line is to be abandoned in place, it should be completely filled with CDF (controlled density fill, a weak concrete mix). The storm drain should be removed, however, if any portion of it will underlie foundations for the new building. The 12 -inch sanitary line should be treated in the same manner as the 48 -inch storm drain. Any voids or new depressions (other than from the existing building demolition) created during site preparation should be cleaned of loose soil or debris and backfilled with structural fill. Depending on the depth of the depression, it might be necessary to dewater the excavation by pumping from sumps. G e o E n g i n e e r s 9 File No. 3944- 002- R01/111094 The surficial soils at the site are moisture - sensitive and will be more difficult to work on or compact during prolonged wet weather. It will be preferable to schedule site preparation and earthwork during periods of dry weather when these soils will be less susceptible to disturbance and will provide better support for construction equipment. However, these activities may be accomplished during the late winter and early spring months provided that appropriate measures are taken by the contractor. If construction activities take place during prolonged periods of wet weather, it might be desirable to leave the existing asphalt pavement intact temporarily to provide a stable working surface for construction equipment. In areas where soils are exposed by site preparation and excavation activities, it might be necessary to protect the subgrade from disturbance by providing a crushed rock or clean sand and gravel working surface. After demolition, removal of existing pavement and void filling are complete, we recommend that building and new pavement area subgrades be proofrolled with heavy, rubber - tired construction equipment if site preparation is done during prolonged dry weather. If this work is done during wet weather, it will be more prudent to keep all but lightweight construction equipment off the subgrade and evaluate the exposed subgrade areas by probing. Any soft, loose or otherwise unsuitable areas detected should be recompacted, if practical, or removed and replaced with structural fill. We recommend that the probing and proofrolling of subgrade areas be observed by a representative of our firm to identify areas needing remedial work and to assess the adequacy of subgrade conditions. We expect that hard silt and sandy silt will be encountered in the excavation made in front of the retaining wall. This excavation should be able to be accomplished using conventional earthmoving equipment. Light ripping plight be required to excavate some of the more hard or dense deposits. The excavation might encounter seepage zones. The contractor should be prepared to collect this seepage with a system of swales and drainage ditches around the base of the excavation so that softening of the exposed subgrade is minimized. All new fill in building and pavement areas should be placed as compacted structural fill. Demolition debris and broken asphalt concrete should be processed, placed and compacted in accordance with the recommendations presented above. All other structural fill should be placed in horizontal lifts not exceeding 10 inches in loose thickness and mechanically compacted to a firm, nonyielding condition. All fill placed beneath foundations and floor slabs should be compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D -1557. Fill placed in pavement areas or in utility trenches within 2 feet of the finished grade should also be compacted to at least 95 percent. At depths greater than 2 feet below the finished subgrade, the fill in pavement areas and utility trenches should be compacted to at least 90 percent. All structural fill soil should be free of organic or made -made contaminants and rock fragments larger than 6 inches in maximum dimension. Particle sizes larger than 3 inches should be excluded from the top 1 foot of fill. The suitability of soil for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines (soil passing G e o E n g i n e e r s 10 File No. 3944 - 002- RO1/111094 the No. 200 sieve) increases, soil becomes increasingly more sensitive to small changes in moisture content and adequate compaction becomes more difficult to achieve. We recommend that structural fill contain no more than about 5 percent fines for placement in wet weather. The percent fines can be higher for placement in dry weather, providing that the fill soil is moisture - conditioned as necessary for proper compaction and that is properly protected from saturation and subsequent softening during wet weather. The soil that will be excavated from in front of the retaining wall contains a substantial percentage of fines and will be highly moisture - sensitive. This soil should be considered for use as structural fill only if it will be worked during periods of dry weather. Completed fills should be capped with a layer of clean sand and gravel fill, wherever possible. We recommend that a representative from our firm observe the placement and compaction of debris and soil structural fill. An adequate number of in -place density tests should be accomplished as the fill is being placed to determine if the specified degree of compaction is being achieved. The settlements of debris and soil structural fill placed and compacted in accordance with our recommendations should be minor, probably less than 1/2 inch. Most of this settlement will occur as the fill is being placed. The general excavation along the toe of the hillside should not be accomplished until the shoring is in place. If any temporary cuts of limited extent are planned to be made without shoring, we recommend that our firm be retained to evaluate the stability and other potential impacts of this action. Heavy plastic sheeting should be used to protect exposed soils on slopes from erosion during wet weather. Ditches or swales should be installed along the top of all cut slopes to intercept runoff and divert it to suitable disposal points. We recommend that any permanent cut slopes in the existing hillside be made no steeper than 13/4 H:1 V. The use of rockeries is considered appropriate only for cuts into the hillside which do not exceed 6 feet in height. Unprotected cut and fill slopes will be subject to erosion until vegetative cover is well established. We recommend that all slope surfaces be planted or seeded as soon as possible. If planting will be delayed after a cut or fill slope is created, we recommend protecting the exposed soil temporarily with plastic sheeting or straw mulch during wet weather. FOUNDATION SUPPORT We recommend that footings for the buildings be founded on the hard silt and medium dense to dense silty sand, or on compacted structural fill. We expect that a variable thickness of existing fill will be encountered in footing excavations, and that it might be necessary at some locations, depending on the condition of the existing fill, to excavate to at least 2 feet below footing grade and place new structural fill. All spread footings should have a minimum width of 2 feet and a depth of embedment below lowest adjacent finished grade of 11/2 feet. Footings designed and installed as recommended may be proportioned using an allowable bearing value of 4,000 pounds per square G e o E n g i n e e r s 11 File No. 3944- 002 - 801/111094 foot (psf) for undisturbed native silt or silty sand and 2,500 psf for compacted structural fill, including existing fill which is determined by field testing to meet the criteria for compacted structural fill. These values apply to the total of dead plus long -term live loads, exclusive of the weight of the footing and any overlying backfill. An increase in these values of up to one -third may be made when considering short-term live loads such as wind or seismic forces. Settlements of footings supported as recommended are expected to be small. We estimate that settlement of footings supporting column loads typical of two -story retail buildings will be on the order of 1/2 to 1 inch. These settlements should occur rapidly as loads are applied. Differential settlements between equally loaded adjacent column footings supported on debris fill and compacted structural fill is not expected to be more than about 1/2 inch. We anticipate that the exposed bearing surfaces in the excavations for footings will become softened or disturbed if not carefully protected during other construction activities. Therefore, we recommend that these excavations be made during periods of dry weather and that all footing excavations be evaluated by a representative of our firm prior to forming footings and slabs or placing structural steel. If footing excavations are made entirely in the hard or dense native soils, it might be possible to cut the excavations so that the footings can be poured neat without forming. If this is attempted, it will be necessary that concrete placement follow excavation within a few hours. It is imperative that the footings be founded on undisturbed native soils or compacted structural fill, as the recommended bearing pressure and settlement estimates are based on this condition. Any loosened, softened or otherwise disturbed soil present in footing excavations should be removed and replaced with compacted structural fill. To prevent deterioration of footing subgrades in the hard silt and dense silty sand due to construction traffic and precipitation, we suggest that 2 inches of lean concrete or 4 inches of clean crushed gravel be placed to protect the bearing surface as soon as it is determined that footing excavations have been properly prepared. FLOOR SLABS We recommend that slab -on -grade floors be supported on a layer of clean, free - draining sand and gravel containing less than 5 percent fines relative to the fraction passing the 3/4 -inch sieve. This free - draining layer should be at least 6 inches thick. We recommend that a vapor barrier be placed between the slab and the free - draining soil layer to minimize the potential for condensation within the underside of the slab, particularly if floor coverings that are sensitive to moisture are used in the buildings. The vapor barrier should be protected by a cover of 2 inches of clean sand to reduce the potential for damage to the barrier by construction worker foot traffic. We estimate that the settlement of floor slabs loaded up to 250 psf and designed and constructed as recommended will be small, probably less than 1/2 inch. G e o E n g i n e e r s 12 File No. 3944- 002- R01/111094 SLOPE RETENTION The existing slope has been cut to an inclination which is judged to be the steepest for which a reasonable factor of safety against sliding can be achieved. Reconfiguring the slope by grading it back to provide sufficient access area on the west side of the three- building complex is feasible from a technical standpoint but unacceptable for reasons of preserving the existing vegetative cover on the slope. Thus, it will be necessary to construct a retaining structure at the toe of the hillside with sufficient resistance to replace the mass of soil removed from the toe. In addition, this wall must be constructed in advance of or concurrently with excavation from the toe so that the stability of the hillside will be maintained at all times. As discussed in a subsequent section, the retention structure must extend below the planned base in order to maintain the factor of safety at a satisfactory level. A cantilever or tieback soldier pile and lagging wall is considered the most viable option for slope retention. One or more rows of tieback anchors will probably be required because of the depth of cut to be made and the backslope of 1.75:1 above the wall. We recommend that at least 2 feet of freeboard be provided at the top of the wall to provide protection against soil and vegetative debris which might ravel down the slope. We recommend that the lateral loads imposed on a soldier pile and lagging system be determined on the basis of a triangular soil pressure distribution based on an equivalent fluid pressure of 70 pcf (pounds per cubic foot) for the upper 10 feet of the wall to account for the presence of fractures in this zone as detected in our explorations. Lateral soil loads below this upper zone and extending down to the base of the cut should be determined using a uniform lateral soil pressure equal to 60 H, where H is the distance from the ground surface at the top of the wall to the base of the excavation. These values take into account the 14H:1V backslope above the wall, and are based on the requirement that hydrostatic pressure above the base of the cut is prevented by installation of recommended drainage measures. An equivalent fluid pressure of 23 pcf should be used for lateral soil loads acting on the embedded portion of the soldier piles. Passive resistance available on soldier piles extending below the level of excavation can be determined using an equivalent fluid density of 300 pounds per cubic foot applied to a width equal to 2.5 times the diameter of the soldier piles or the spacing between the piles, whichever is less. This equivalent fluid density value includes a factor of safety of 1.5. We recommend that the soldier piles be embedded a minimum of 15 feet below the planned base of excavation for the reasons discussed in the section, "Slope Stability." The vertical capacity of the soldier piles to resist the downward component of anchor loads and other axial loads can be evaluated using an allowable end- bearing value of 12 kips per square foot applied to the base area of the drilled hole into which the soldier pile is concreted. If additional downward resistance is required, an adhesion value of 800 pounds per square foot can be used. These values both include a factor of safety of about 2.5. The allowable capacities may be increased by one -third for short -term loads, such as seismic forces. GeoEngineers 13 File No. 3944-002-R01/111094 The holes which are drilled for installation of the soldier piles will likely encounter seepage. Measures might be necessary to prevent sloughing, caving, or "running" of soil into the drilled hole. The contractor should be prepared to use casing or other techniques, as necessary, to stabilize the drilled holes. We estimate that settlements of soldier piles designed and installed as recommended will be on the order of 1/2 inch or less. Settlements will occur rapidly as loads are applied. Timber lagging should be installed between the soldier piles as the excavation progresses downward to limit spalling and loosening of soil in back of the wall and to provide a smooth surface against which to place drainage material. The permanent facing for the wall (such as cast -in- place, precast or sprayed concrete) can then be installed against the drainage material. We recommend that tieback anchors consist of augered and grouted anchors extending far enough into the hillside so that all load - carrying capability is developed behind a "no- load" zone which represents the zone of yielding within the hillside to develop active pressures. This "no load" zone is defined as that area behind the wall for a distance of one - quarter the height of the wall measured horizontally at its base and then extending upward at an angle of 60 degrees from the horizontal until this line intersects the ground surface. We recommend that the tieback anchors be installed no flatter than 15 degrees below the horizontal so that the potential for failure along the horizontally oriented layers of silt can be minimized. Tieback anchors should be double- corrosion protected since they will support load on a permanent basis. They should be designed and installed in general accordance with the criteria presented in the following documents: 1. U.S. Department of Transportation, Federal Highway Administration, "Permanent Ground Anchors," Report FHWA- DP- 68 -1R, 1984. 2. U.S. Department of Transportation, Federal Highway Administration, "Tiebacks," Report FHWA /RD- 82/047, 1982. 3. Post- Tensioning Institute, "Recommendations for Prestressed Rock and Soil Anchors," 1980. Tieback anchors may be sized using a frictional resistance between the grout encasing the anchors and the surrounding soil of 650 pounds per square foot. A 30 percent increase in adhesion value can be used when considering seismic loads. We recommend that spacing between tiebacks be at least 3.5 times the anchor hole diameter to minimize group interaction. The friction value presented above includes .a factor of safety of about 3 but should be confirmed by proof testing all anchors to 135 percent of design load. Selected anchors should be tested to 200 percent of design load to confirm design values. We suggest that at least six anchors be loaded to this higher level. Anchors that do not meet the test criteria should be rejected and replaced or modified by the contractor at no expense to the owner. After completing the performance and proof tests, the anchors should be locked off at 80 percent of the design load or at the load which results in 1 inch of movement of the top of the soldier pile into the slope, whichever is less. G e o E n g i n c e r s 14 File No. 3944- 002- R01/111094 We recommend that a member of our staff observe the installation of the soldier piles and tieback anchors, as well as monitor, record and evaluate all performance and proof testing of the anchors. The lateral soil pressures presented in this report assume that drainage will be provided through or behind soldier pile walls such that hydrostatic water pressures do not build up against the walls. Several types of drainage systems can be considered for walls on which the permanent facing is installed directly against the soldier pile and lagging. For planning purposes, we anticipate that Alidrain, Miradrain, or an equal system might be used to provide drainage for permanent soldier pile walls. The drains must be hydraulically connected to an appropriate collection system at the base of the wall. SLOPE STABILITY The overall stability of the hillside following grading in the 1960s was evaluated by Dames & Moore using strength parameters developed from laboratory testing of samples obtained from several borings drilled in the hillside. Based on these analyses, Dames & Moore concluded that the factor of safety for the slope inclined at 13 /a H: IV is 1.25 under static conditions, with the factor of safety decreasing by 0.1 to 0.2 with a seismic force equivalent to 0.1g. The satisfactory performance of this slope appears to confirm the assumptions and analyses accomplished by Dames & Moore. We evaluated the stability of the existing and modified hillside configuration using the computer program XSTABL developed by Sunil Sharma of Interactive Software Designs, Inc. and based on the STABL program developed at Purdue University. This program has the capability of analyzing slope stability for a wide range of slope and failure surface geometries with multiple subsurface layers and ground water levels. The slope profile, soil conditions and ground water level used in our analyses are shown in Figure 3 and also in graphs included along with computer printouts in Appendix B. The first step in the analyses was to back - calculate soil strength values which resulted in a factor of safety of about 1.25 for the existing slope under static conditions. When a horizontal acceleration of 0.1 g is included, the factor of safety of the slope, using the back - calculated strength data, decreases to about 1.03. Based on these results and on strength tests accomplished for the Dames & Moore study and our current study, we selected a friction angle of 37 degrees and a cohesion of 25 pounds per square foot for our analyses. The second stage in our analyses was to use these soil parameters to evaluate the effect of excavation at the toe of the hillside. Analyses were run for a retaining wall with and without embedment below the depth of cut. Factors of safety for a soldier pile embedment of 15 feet below the base of the cut are 1.8 for static conditions and about 1.2 for a horizontal acceleration coefficient of 0.2g. For a wall with little or no embedment (for example, a soil nail wall or a gravity wall), the factors of safety decrease to 1.26 and 0.95, respectively, for static and dynamic conditions. G e o E n g i n e e r s 15 File No. 3944- 002- R01/111094 A buffer between the hillside and the west edge of the three- building complex will not be required because of the presence of the retaining wall which, if designed and constructed in accordance with our recommendations, will maintain the stability of the hillside. In addition, the wall will be designed with at least 2 feet of freeboard to provide protection against ravelling. SURFACE DRAINAGE A drainage swale or ditch should be installed just above the retaining wall during and following construction to intercept and control any surface water flowing down the hillside. The swale or ditch should be sloped to drain toward both the north and south away from the center of the wall. A suitable drainage system should be installed in conjunction with the proposed buildings. This drainage system should be capable of collecting runoff from the buildings and surrounding pavement areas and directing it to an appropriate disposal system. PAVEMENTS Pavement subgrade areas should be prepared as recommended under "Site Preparation and Earthwork." We recommend that the design pavement section in automobile parking areas consist of 2 inches of Class B asphalt concrete, 4 inches of crushed rock base course, and an appropriate thickness of clean pit run sand and gravel. In truck and heavy traffic areas, the design pavement section should consist of 3 inches of Class B asphalt concrete, 6 inches of crushed rock base course, and an appropriate thickness of clean pit run sand and gravel. ATB (asphalt- treated base) can be substituted for the base course to provide a working surface and staging area for construction. Areas of ATB that experience severe cracking during construction should be repaired or replaced an the entire surface releveled prior to placing the asphalt surfacing. The thickness of pit run required beneath new pavement will depend on the time of year of construction, the presence of existing asphalt pavement, and the difference between finished and existing grades. We can provide more specific recommendations for pit run thickness once finished grades and construction schedules have been determined. UNDERGROUND UTILITIES We expect that trenching for most of the underground utilities on the site will encounter existing fill or hard and dense native soils. Relatively shallow ground water levels might also be encountered, depending on the depth of the utility and the time of year for construction. If utility trench excavations extend below the ground water level, we anticipate that trench boxes or other means of shoring will be necessary. Depending on the depth of trench, dewatering might also be necessary. G e o E n g i n e e r s 16 File No. 3944 - 002- R01/I11094 In our opinion, normal bedding requirements should be satisfactory. This will include surrounding all pipes with a minimum of 6 inches of pea gravel or other granular soil. Utility backfill should be compacted as recommended in "Site Preparation and Earthwork." LIMITATIONS We have prepared this report for use by Mr. Roy Bennion and the design team in design of a portion of the project. The data and report should be provided to your contractor for estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. If there are any changes in the loads, grades, locations, configurations or types of facilities planned, the conclusions and recommendations presented in this report might not be fully applicable. If such changes are made, we should be retained to review our conclusions and recommendations and to provide written modification or verification, as appropriate. When the design has been finalized, we should also be retained to review the final design drawings and specifications to see that our recommendations have been interpreted and implemented as intended. The scope of our services does not include services related to construction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. There are possible variations in subsurface conditions between the locations of the explorations and also with time. A contingency for unanticipated conditions should be included in the project budget and schedule. We recommend that we be retained to provide sufficient monitoring, testing and consultation during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with the contract plans and specifications. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in this area at the time the report was prepared. No other conditions, express or implied, should be understood. G e o E n g i n e e r s 17 File No. 3944 - 002- R01/111094 The conclusions and recommendations in this report should be applied in their entirety. If there are any questions concerning the report or if we can provide additional services, please contact us. EXPIRES /c7— 16~ 96 HRP:JKT:cms Document ID: 3944002.R G e o E n g i n e e r s Yours very truly, GeoEngineers, Inc. VA-g, Ak.h, Herbert R. Pschunder, P.E. Senior Engineer Jack K. Tuttle, P.E. Principal 18 File No. 3944 - 002 - 801/111094 344 &oz •,ev/ /IRP=7H i //if• VICINITY MAP o TO BELLEVUE SEE STREET P.ENTON MAP OF INSET `° AREA TO SEATAC AIRPORT TUKWILA SOUTHCE TER TO TACOMA bc05 OLONG AC SW. 43RD Slxttr PETROV I1SKY Rf✓'-----., STREET MAP SOUTHCENTERR LVD. ...Ill SOUTH B. AKER CENTER STRANDER BLVD. PARKWAY PLAZA(SITEY- 17501 SOUTHCENTER , TUKWILA, WA > �� PARKWAY S. 180TH STREET 0 GRADY WAY I NTERSI A1E 405 4 LONGACRES RACETRACK tAi ca W u w w J Q .> �`' A. 402 STRANDER BLVD. 44. TUKWI LA, WA. SW 43 RD STREET No Scale 0 Reference: Drawing entitled Site Plan, Parkway Place,' by Turner and Associates, Architects, dated 09/15/94. Geo ,O Engineers VICINITY MAP AND STREET MAP FIGURE 1 H4P 591/ / / EXPLANATION: B -1* TP -1* B -14 1* *B-4 Proposed Building A \� -2 0 A' \ - Proposed \ Retaining Wall *19 —>— --B -5 TEST BORING FOR CURRENT STUDY TEST PIT FOR CURRENT STUDY TEST BORING BY OTHERS TEST PIT BY OTHERS APPROXIMATE EDGE OF COMPRESSIBLE ALLUVIAL SOILS • 4 4 A' CROSS SECTION 18 - -7 B -64 *17 *12 B -1 TP -2 -B -2 Proj Reti Proposed Three Building Complex (Buildings B, C and D) -A Existing Nine Story Building 1 B -2A + B -2 22 *25 Existing Building B76 -2 1 -- 6 A411111 -13-4 References: 1. Drawing entitled Site Plan, Parkway Place, Tukwila," by Turner and Associates, dated 09 /15/94. 2. Topographic site plan prepared by Chadwick Surveying & Engineering, dated 10/26/94. 4.10 SOujHG eft PPVVKWPY Geo �O Engii 0 A' oh A\y`yp Mh��°�� t 410 `6 too 5 ,-- Proposed \ Retaining Wall TP-2 B -1 B -2 Pro d Retaining Wall- B -3 Proposed Three Building Complex (Buildings B, C and D) -(1)-A Existing Nine Story Building B -2A -�- B -2 A 22 5 13 -4110 *6 *21 4B -7 127 ----� 26 *28 *4 soTea PPOOPI *24 ,s J Property Line 3s � 1 _ Existing Rail Spur Right -of -Way Z—. 100 SCALE IN FEET Geo O Engineers SITE PLAN FIGURE 2 A 250- 200- A (Offset 175' South) Proposed Three Building Complex W J a 0 a Approximi Ground St Proposed • Retaining Wall ?— Hard sandy silt and silt with clay and interbedded layers of silty sand Notes: 1. Elevations are based on survey information developed by Chadwick Surveying & Engineering, using 1929 NGVD datum, and on City of Tukwila Public Works Department Geologic Hazards Maps. 2. This cross section is a diagrammatic interpretation of subsurface conditions based on extrapolation of data from widely spaced borings. Actual conditions are substantially more complex than depicted. GeoEngineers does not represent the conditions illustrated as exact: ? Very de gravel HORIZONTAL EXPLANATIC Geo O Engii •— 1g Wall a) J a) 0 a Hard sandy silt and silt with clay and interbedded layers of silty sand ;loped by Chadwick Surveying & ity of Tukwila Public Works Department on of subsurface conditions based on s. Actual conditions are substantially more represent the conditions illustrated as exact: z — Approximate Existing Ground Surface Very dense silty sand with gravel and cobbles (glacial till) HORIZONTAL AND VERTICAL SCALE: 1" = 50 EXPLANATION: BORING f N GROUND WATER ELEVATION Northbound 1 -5 A' -250 -200 -150 100 Geo i Engineers GENERALIZED SUBSURFACE CROSS SECTION A = A': FIGURE 3 APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING FIELD EXPLORATIONS Surface and subsurface conditions at the project site were explored by conducting a geologic reconnaissance, drilling 7 borings and excavating 3 test pits. These field activities were accomplished between November 1 and 4, 1994. The exploration locations are shown in Figure 2. These locations were determined by taping from existing site features. Figure 2 also shows the locations of previous explorations accomplished by others in the vicinity of the planned construction. Ground surface elevations at the exploration locations were determined by interpolation from contour lines shown on topographic survey plans prepared by Chadwick Surveying and Engineering. These elevations are based on the 1929 NGVD datum. Exploration locations and elevations should be considered accurate only to the degree implied by the methods used. The borings were drilled on November 3 and 4, 1994 to depths ranging from 9.0 to 49.0 feet below existing grade using a truck - mounted, continuous - flight, hollow stem auger drill. The locations of borings B -1 through B -3 were chosen to coincide with the locations of test pits TP -1 through TP -3. A track - mounted excavator was used to prepare an access route to these three boring locations and also to dig the corresponding test pits. Representative samples were obtained of each soil type encountered in the borings. These samples were obtained using a 2.4- inch - diameter, split - barrel sampler. The sampler was driven into the soil using a 300 -pound hammer free - falling 30 inches. The number of blows required to drive the sampler the last 12 inches, or other indicated distance, is recorded in the boring logs. The test pits were excavated upslope from the lowest bench on the hillside using the track - mounted excavator. The excavator boom was able to reach about 20 vertical feet above the bench level. Test pit depths ranged from 17.3 to 22.0 feet measured relative to the upslope end of the test pit. The explorations were continuously monitored by a representative of our firm, who identified the exploration locations, classified the soils encountered, obtained representative disturbed and undisturbed samples of the various soil strata, observed seepage and ground water conditions, maintained a detailed log of each exploration, and assisted in the installation of piezometers in the borings. Soils were classified in general accordance with the classification system described in Figure A -1. A key to the boring log symbols is presented in Figure A -2. Logs of the borings are presented in Figures A -3 through A -9. The log of boring A, which was drilled by others in 1964 before the site was graded to the present configuration, is included as Figure A -10. Test pit logs are presented in Figures A -11 through A -13. The exploration logs are based on our interpretation of the field and laboratory test data and indicate the various soil G e o E n g i n e e r s A - 1 File No. 3944 - 002- R01/111094 types encountered. They also indicate the depths at which these materials or their characteristics change, although the change might actually be gradual. If the change occurred between samples, it was interpreted. Observations of ground water conditions were made as the explorations were accomplished. In addition, piezometers were installed in borings B -1 through B -3 to monitor ground water levels following drilling. The ground water levels in these piezometers, as measured on November 7, 1994, are presented on the boring logs. LABORATORY TESTING All soil samples were brought to our laboratory for further examination. Selected samples were tested to determine their moisture content, dry density, gradation and shear strength characteristics. The results of the moisture content and dry density tests are presented on the boring logs and also in Figure A -14. Gradation tests were accomplished on two samples. Results of the gradation tests are presented in Figure A -15. Strain - controlled direct shear tests were accomplished on several samples obtained from the borings. Direct shear test results are summarized in Figure A -16. G e o E n g i n e e r s A - 2 File No. 3944. 002 -R01 /111094 M 0 0 krt 00 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS More Than 50% Retained on No. 200 Sieve GRAVEL More Than 50% of Coarse Fraction Retained on No. 4 Sieve CLEAN GRAVEL GW WELL- GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY- GRADED GRAVEL GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL SAND More Than 50% of Coarse Fraction Passes No. 4 Sieve CLEAN SAND SW WELL- GRADED SAND, FINE TO COARSE SAND SP POORLY- GRADED SAND SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS More Than 50% Passes No. 200 Sieve SILT AND CLAY Liquid Limit Less Than 50 INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY Liquid Limit 50 or More INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS: 1. Field classification is based on visual examination of soil Dry - Absence of moisture, dusty, dry to the touch in general accordance with ASTM D2488 -90. Moist - Damp, but no visible water 2. Soil classification using laboratory tests is based on ASTM D2487 -90. Wet - Visible free water or saturated, usually soil is obtained from below water table 3. Descriptions of soil density or consistency are based on interpretation of blow count data, visual appearance of soils, and /or test data. -i1 Geo OEngineers SOIL CLASSIFICATION SYSTEM FIGURE A -1 GEI86 -88 R LABORATORY TESTS: AL CP CS DS GS %F HA SK SM MD SP TX UC CA Atterberg limits Compaction Consolidation Direct shear Grain -size Percent fines Hydrometer analysis Permeability Moisture content Moisture and density Swelling pressure Triaxial compression Unconfined compression Chemical analysis BLOW COUNT /SAMPLE DATA: Blows required to drive a 2.4 -inch 1.D. split - barrel sampler 12 inches or other indicated distances using a 300 -pound hammer falling 30 inches. Blows required to drive a 1.5 -inch I.D. (SPT) split - barrel sampler 12 inches or other indicated distances using a 140 -pound hammer falling 30 inches. "P" indicates sampler pushed with weight of hammer or against weight of drill rig. NOTES: SOIL GRAPH: SM Soil Group Symbol (See Note 2) Distinct Contact Between Soil Strata Gradual or Approximate Location of Change Between Soil Strata Water Level Bottom of Boring 22 ■ Location of relatively undisturbed sample 12 ® Location of disturbed sample 17 ❑ Location of sampling attempt with no recovery 10 0 Location of sample obtained in general accordance with Standard Penetration Test (ASTM D 1586) procedures 26 m Location of SPT sampling attempt with no recovery Location of grab sample 1. The reader must refer to the discussion in the report text, the Key to Boring Log Symbols and the exploration Togs for a proper understanding of subsurface conditions. 2. Soil classification system is summarized in Figure A -1. Geo �O Engineers KEY TO BORING LOG SYMBOLS FIGURE A -2 O O a TEST DATA Moisture Dry Content Density Blow Group Lab Testa ( %) (pct) Count Samples Symbol BORING B -1 DESCRIPTION Surface Elevation (ft.): 54.6 5 10 15 LL uw - c 20 25 30 35 40 MD 24 95 DS, 38 82 MD MD 26 95 MD, 26 98 GS MD 25 101 MD 27 97 35 20 31 40 39 66 66 ML ML Gray silt with occasional fine sand (hard, moist) Orange and gray sandy silt (hard, moist) ML Light grayish brown sandy silt with a trace of clay (hard, moist) MUSM Brown sandy silt with intcrbeds of silty fine sand (hard /dense, moist) ML ML ML ML Orange and brown sandy silt (hard, moist) Brownish gray sandy silt (hard, wct) Dark brown silt (hard, moist) Orange and brown silt with a trace of fine sand (hard, moist) SP -SM Gray fine sand with silt (very dense, moist) J Notc: See Figure A -2 for explanation of symbols Geo Engineers LOG OF BORING FIGURE A -3 :SDS :HRP:CMS 11/9/94 3944- 002 -R01 DEPTH IN FEET 40 TEST DATA Moisture Dry Content Density Blow Group Lab Tests (%) (pct) Count Samples Symbol BORING B -1 (Continued) DESCRIPTION MD 31 91 45— SM 16 •50— 44 50/5" ML Brown sandy silt (hard, wet ML/SM Gray silt with occasional fine sand and interbedded layers of silty fine sand (hard /dense, wet) SP Gray fine to medium sand (very dense, wet) 40 — 45 Boring completed at 49.0 feet on 11/03/94 Ground water seepage encountered at 28.0 and 40.0 feet during — 50 drilling Piezomcter installed at 49.0 fcet Ground water level measured at 31.1 feet on 11/07/94 55 55 60^ —60 65— —65 70— —70 75 — 80 — Note: See Figure A -2 for explanation of symbols — 75 80 Geo ,O Engineers LOG OF BORING FIGURE A -3 :SDS:HRP:CMS 11/9/94 3944- 002 -R01 TEST DATA Moisture Dry Content Density Blow Group Lab Tests (%) (pep Count Samples Symhol 0 BORING B -2 DESCRIPTION Surface Elevation (R.): 57.6 5— 10 15 25 30 35 40 Note: See Figure A -2 for explanation of symbols Geo Engineers LOG OF BORING FIGURE A -4 SP Gray fine sand with a trace of silt (dense, moist) Dark brown silt with organic matter (very stiff, moist) - Light greenish gray silt with a trace of fine sand and occasional _ ML ML MD 29 94 51 I1 fractures (hard, moist) DS, 34 89 83 1 MD MD 27 96 50/5" ■ : SM Gray silty fine to medium sand (very dense, moist) _ 50/5* ML Gray sandy silt (hard, moist) - 50/4" 11 : • SM /ML interbedded layers of gray silty fine sand and sandy silt (very dense/ hard, moist) DS, - MD 42 77 50/4" OL Dark brown organic silt (hard, moist) Gray silt with clay (hard, moist to wet) ML _ ML Gray sandy silt (hard, moist to wet) MD 24 102 50/4' ■ 50/3' ■ 5— 10 15 25 30 35 40 Note: See Figure A -2 for explanation of symbols Geo Engineers LOG OF BORING FIGURE A -4 :SOS:HRP:CMS 11/9/94 3944- 002 -R01 TEST DATA Moisture Dry Content Density Blow Group Lab Tests ( %) (pcf) Count Samples Skmbol 40 50/3" 45-1 72 50 — 55— BORING B -2 (Continued) DESCRIPTION 40 — 45 Boring completed at 49.0 feet on 1 1/04/94 Ground water seepage encountered at 28.0 and 38.0 feet during — 50 drilling Piczometer installed at 48.0 feet Ground water level measured at 29.6 feet on 11/07/94 ^55 — 60 65— --65 70— —70 75— —75 80— —80, Note: See Figure A -2 for explanation of symbols gm. Geo [,,,Engineers LOG OF BORING FIGURE A -4 . :SDS:HRP:CMS 11/9/94 3944 - 002 -R01 0 TEST DATA Moisture Dry Content Density Blow Group Lab Tests (%) (pct) Count Samples Symbol BORING B -3 DESCRIPTION Surface Elevation (It.): 52.3 10— 15 w w u_ Z x o 20 25 30 35 0 5 10 15 20 25 30 35 40 --40 Note: See Figure A -2 for explanation of symbols Geo Engineers LOG OF BORING FIGURE A -5 1 1 ( OL SP -SM Dark brown organic silt (hard, moist) Gray fine sand with silt (very dense, moist) = DS, MD 24 96 50/5" 1 ML OL Orange and brown sandy silt (hard, moist) Dark brown organic silt (hard, moist) ML Gray silt with clay (hard, moist) MD 33 89 67 A SM Brown and gray silty fine sand (very dense, moist) SM/ML Interbedded gray and brown silty fine sand and sandy silt (very MD 23 97 61 dense /hard, moist) - �,*:---- ML Greenish gray silt with clay (hard, moist) 58 ■ MD 27 97 98/8" ML Gray sandy silt (hard, wet) MD 29 95 99/8* r 81/8" ■ OL Dark brown organic silt (hard, moist) ML Gray sandy silt (hard, moist) 71/7" ■ 10— 15 w w u_ Z x o 20 25 30 35 0 5 10 15 20 25 30 35 40 --40 Note: See Figure A -2 for explanation of symbols Geo Engineers LOG OF BORING FIGURE A -5 :SDS:HRP:CMS 11/9/94 3944. 002 -R01 40 TEST DATA Moisture Dry Content Density Blow Group Lab Tests ( %) (pcf) Count Samples S7mbo1 MD 22 105 45 — 50— 55— -4 65 — 73 32 BORING B -3 (Continued) DESCRIPTION CL Greenish gray sandy clay (hard, moist to wet) SM Brown silty fine sand with occasional medium sand (dense, wet) Boring completed at 49.0 feet on 11/04/94 Ground water seepage encountered at 27.5 and 34.0 feet during drilling Piczometer installed at 49.0 feet Ground water level measured at 23.0 feet on 11/07/94 40 — 45 50 —55 — 60 — 65 70— -70 75— —75 80— —80 Note: Sec Figure A -2 for explanation of symbols Geo ° Engineers LOG OF BORING FIGURE A -5 DS:HRP:CMS 11/9/94 3944 - 002 -RO1 • TEST DATA BORING B -4 Lab Tests 0 5— 10— 15— w w N o. w 0 20— 25 — 30 — 35— Moisture Dry Content Density Blow Group (%) (pcf) Count Samples Symbol SM 29 MD 26 98 69 74 1 DESCRIPTION Surface Elevation (IL): 31.7 0 c ASPHALT GP ML Asphalt concrete pavement 1.5 inches thick Brown fine to coarse gravel with fine to medium sand (medium dense, moist) (fill) Greenish gray silt with clay and a trace of fine sand (medium stiff, moist) ML Gray silt with fine sand (hard, moist) :::M: SP -SM Reddish brown line to medium sand with silt (very dense, moist) Boring completed at 9.0 feet on 11/03/94 No ground water encountered during drilling 5 10 15 20 25 30 35 40— t_ 40 Note: Sec Figure A -2 for explanation of symbols Geo %O Engineers LOG OF BORING FIGURE A -6 :SDS:HRP:CMS 11/9/94 3944- 002 -R01 DEPTH fN FEET TEST DATA Moisture Content Lab Tests ( %) 0— 5— 10— 15— 20 — 25 — 30 — 35— 40 — MD 30 MD 40 Density Blow Group (pct) Count Samples Symbol BORING B -5 DESCRIPTION Surface Elevation (ft.): 30.2 92 11 76 57 64 ■ 1 0 ASPHALT GP -GM ML ML OL ML Note: See Figure A -2 for explanation of symbols Asphalt concrete pavement 2.5 inches thick Brown fine to coarse gravel with silt and fine to medium sand (medium dense, moist) (fill) Brown sandy silt with occasional organic matter (stiff, moist) Gray silt with occasional fine sand (hard, moist) Dark brown organic silt (hard, moist) Gray silt with occasional fine sand (hard, moist) Boring completed at 9.0 feet on 11/03/94 No ground water encountered during drilling Geo '•` Engineers LOG OF BORING FIGURE A -7 :SDS :HRP:CMS 11/9/94 3944 - 002 -A01 TEST DATA Moisture Dry Content Density Blow Group Lab Teets ( %) (pct) Count Samples S mbol 0 5— 10— 25 — 30— 35— 40 — MD 15 122 21 8 9 21 31 BORING B -6 DESCRIPTION Surface Elevation (ft.): 30.9 ASPHALT GP -GM SM GM Asphalt concrete pavement 2 inches thick Brown fine to coarse gravel with silt and fine to coarse sand (medium dense, moist) (fill) Brown silty fine to medium sand (medium dense, moist) (fill) Gray silty fine to coarse gravel with sand (medium dense, moist to wet) (fill ?) SM Brown silty fine to medium sand with gravel (medium dense, wct) Note: See Figure A -2 for explanation of symbols Boring completed at 19.0 feet on 11/04/94 Ground water seepage encountered at 4.5 feet during drilling Geo ,,,, Engineers LOG OF BORING FIGURE A -8 :SDS:HRP:CMS 11/9/94 3944. 002 -R01 TEST DATA Moisture Dry Content Density Blow Group Lab Tests ( %) (pet) Count Samples S� mbol MD 9 131 10— 38 15 52 BORING B -7 DESCRIPTION Surface Elevation (ft.): 33.1 o ASPHALT Asphalt concrete pavement 2 inches thick o GP -GM Brown fine to coarse gravel with silt and sand (medium dense, SM moist) (fill) Brown and gray silty fine to medium sand with gravel (medium dense to dense, moist) Grades with less gravel ML Greenish gray silt with fine sand (hard, moist) SP -SM Light gray fine to medium sand with silt (very dense, moist) —0 —5 Boring completed at 9.0 feet on 11/04/94 No ground water encountered during drilling —10 15— —15 w w w U. x w 20— 25— 30— — 20 — 25 —30 35— —35 40— --40 Note: See Figure A -2 for explanation of symbols Geo !Engineers LOG OF BORING FIGURE A -9 fp 0 5 tip 10 15 (7,0 20 25 12.1) 30 !ro DEPTH 114 FEET 35 40 45 /6y 50 55 9m 60 65 75 BORING A SLRFACL EL I VAT I01. ISO! (ESTIMATCU) N0 LEO N A WITH GRAVEL (FIRM) (GM) MOTTLED BROW AND GRAY SILT 11IR14) (ML) BROWN AND GRAY SILTY LOAM (FIRM) (14 -sM) BROWNISH GRAY FINE TO MEDIUM SAND (COMPACT) (ST) CONTAINS GRAVEL BROW ISH GRAY SANDY LOAM WITH GRAVEL, COBBLES AND BOULDERS (VERY F1RM) ( GLACIAL TILL) (GM) MOTTLED BROWN AND GRAY SILT WITH OCCAS- IONAL GRAVEL (FIRM) (ML) BROMI FINE TO COARSE SAND WITH GRAVEL AND COBBLES (COMPACT (GW) BLUISH GRAY SANDY LOAM WITH GRAVEL (VERY CM,PACT) (GLACIAL TILL) (GM) GRADES BROWN A40 GRAY IN COLOR 9R01N FINE SANDY LOAM WITH LAYERS OF SILT (VERY FIRM) (L-`4) %DTI : PRELI'INARY WATER LE1.EL OBSERVED A-28-6A AT A DEP7h OF 123 FEET BELOW GR0. \D S.al ACE. 75 1b 80 by 85 BLUISH GRAY SILT (VERY FIRM) (PL) • BROWN FINE SANG (V(. Y CONTACT) (ST) 90 . 95 51) 100 DEPTH 1M FEET 105 110 115 '.0 120 125 IA 130 135 10 140 145 GRAY SILTY CLAY (VERY FIRM) (ML) NLUISYi GRAY FINE TO MEDIUM SAND (VERY COMPACT) (SP) GROUNDWATER SELPAGE GRAY SILT WITH LAYERS OF SILTY CLAY (VEP'I FIRM (ML) GRAY SILT WITH LAYERS AND LENSES G FINE SAND (VERY FIRM) (AIL) O 150 BLOWS REQUIRED TO DRIVE SAMPLER ONE FOOT WEIGHT . 200 LBS., STROKE - 24 INCHES ■ INDICATES DEPTH AT WhICH UNDISTURBED SAMPLE WAS EXTRACTED LOG OF BORINGS ZONE OF GROUND WATER SEEPAGE GRAY SILTY LOAM (VERY FIk1) (ML -SM) BORING CASLU 10 A DLPIH Of 13° FELT EDAM MIS IS MOOTS APPLIED EARTH SCIENCES DEPTH BELOW SOIL GROUP GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT TP -1 Appmximate surface elevation: 73.5 feet 0.0 - 0.5 ML Dark brown silt with organic matter and forest duff (medium stiff, moist) 0.5 - 1.2 CL Brown and orange clay with occasional fine sand and fractures (hard, moist) 1.2 - 2.5 SP Brown fine sand with a trace of silt (dense, moist) 2.5 - 4.3 ML Brown and orange silt with occasional fine sand and fractures (hard, moist) 4.3 - 6.5 SM Light brownish gray silty fine sand (dense, moist) 6.5 - 9.0 ML Gray silt with a trace of clay and occasional fine sand (hard, moist) 9.0 - 12.5 ML Brown and orange silt with occasional fine sand and fractures (hard, moist) 12.5 - 14.0 SM /ML Orange and gray silty fine sand and sandy silt (dense /hard, moist) 14.0 - 16.0 ML Brown sandy silt with a trace of clay (hard, moist) 16.0 - 19.0 ML Orange and gray silt with occasional fine sand and fractures (hard, moist) Test pit completed at 19.0 feet on 11/03/94 No ground water seepage observed during time test pit was open Thin wall sample obtained at 4.5 feet Disturbed soil samples obtained at 1.0, 2.0 and 14.5 feet THE DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FOOT, ARE BASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FOOT. Geo pe Engineers LOG OF TEST PIT FIGURE A -11 DEPTH BELOW SOIL GROUP GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT TP -2 Approximate surface elevation: 79.5 feet 0.0 - 0.5 OL Dark brown organic silt and forest duff (soft, moist) 0.5 - 3.5 ML Orange and grayish brown silt with occasional fine sand seams and fractures (hard, moist) 3.5 - 5.0 SM Light grayish brown silty fine sand (dense, moist) 5.0 - 6.5 ML Gray silt with occasional fractures (hard, moist) 6.5 - 9.5 ML Orange and brown silt with clay and fractures (hard, moist) 9.5 - 14.5 ML Gray and brown silt with occasional fine sand seams (hard, moist) 14.5 - 16.0 ML Orange and brown silt with clay (hard, moist) 16.0 - 20.0 SP -SM Light brown fine sand with silt (dense, moist) 20.0 - 20.5 ML Gray silt with occasional fine sand (hard, moist) 20.5 - 22.0 SP Gray fine sand (dense, moist) Test pit completed at 22.0 feet on 11/03/94 No ground water seepage encountered during time test pit was open Thin wall sample obtained at 4.0 feet Disturbed soil samples obtained at 2.5, 17.0 and 21.0 feet THE DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FOOT, ARE BASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FOOT. Geo l,O Engineers LOG OF TEST PIT FIGURE A -12 DEPTH BELOW SOIL GROUP GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT TP -3 Approximate ground surface elevation: 69.5 feet 0.0 - 0.3 ML Dark brown sandy silty with organic matter (soft, moist) 0.0 - 1.0 SM Orange and brown silty fine sand with occasional roots (medium dense, moist) 1.0 - 3.3 SM Orange and brown silty fine sand with occasional gravel and fractures (dense, moist) 3.3 - 5.0 ML Gray silt with a trace of fine sand (hard, moist) 5.0 - 7.0 ML Orange and brown silt with clay and fine sand (hard, moist) 7.0 - 11.0 SM /ML Interbedded layers of brown silty fine sand and gray silt with fine sand (very dense /hard, moist) 11.0 - 11.5 OL Dark brown organic silt (hard, moist) 11.5 - 14.0 ML Greenish brown silt with clay and occasional organic matter and fine sand (hard, moist) 14.0 - 15.5 SM Brown silty fine sand (very dense, moist) 15.5 - 16.0 ML Greenish brown silt with clay (hard, moist) 16.0 - 16.8 SM Gray silty fine sand (very dense, moist) 16.8 - 17.3 OL Dark brown organic silt (hard, moist) Test pit completed at 17.3 feet on 11/04/94 No ground water seepage observed during time test pit was open Thin wall sample obtained at 4.3 feet Disturbed soil sample obtained at 2.7 feet THE DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FOOT, ARE BASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FOOT. Geo O Engineers LOG OF TEST PIT FIGURE A -13 TEST PIT MOISTURE CONTENT DATA Test Pit Number Depth of Sample (feet) Soil Classification Moisture Content ( %) TP -1 1.0 ML 32 TP -1 4.5 SM 8 TP -1 14.5 ML 32 TP -2 2.5 ML 31 TP -2 4.0 SM 4 TP -3 4.3 ML 29 Geo ,,�_, Engineers MOISTURE CONTENT DATA FIGURE A -14. c7 N — eo — I I I 1 ' 1 1HJ13M AB JNISSVd 1■30Fi3d I ' 0 0 0 0 r w 2 z SILT OR CLAY z W 2 w to cc 0 J w 2 w z w N cc 0 U N 0 U SOIL DESCRIPTION Silty fine sand with occasional gravel (SM) Ir SAMPLE DEPTH (FEET) Mc M° r EXPLORATION NUMBER J • , 1,/ Geo Engineers GRADATION CURVES FIGURE A -15 GEI 85 -85 Rev. 05/93 DIRECT SHEAR TEST DATA Yield Strength* (lsf �g NM g$ c4 it; §§ MN §§ c Confining Pressure (Psi) §§ N 4 §§ N d' §§ cf kO §§ (-4',d-- ,d- Dry Density (Pcf) 00 00 N VD Moisture Content ( %) M M •:1- N Sample Description Sample Depth (feet) - - O 00 O 00 0 o� N O M Boring Number ---i N N M *Samples sheared at a strain rate of 0.04 inches /minute. Geo •Engineers DIRECT SHEAR TEST DATA FIGURE A -16 h N N 11 -07 -94 z INITIAL CONDITIONS 3944 - 002 —R01 CO u) N 11 rn 0 L rZ 0 E5' z 10 most critical surfaces, 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 11) Co N 00 M (leeJ) SIXd —Ji 0 - 0 O) 0 Ln m 4- o M X X 0 N N 0 o XSTABL File: SMS -IN3 11 -07 -94 12:57 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** X S T A B L Slope Stability Analysis using the Method of Slices Copyright (C) 1992 a 94 Interactive Software Designs, Inc. Moscow, ID 83843, U.S.A. All Rights Reserved * * * Ver. 5.005 94 a 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * Problem Description : 3944 - 002 -RO1 INITIAL CONDITIONS SEGMENT BOUNDARY COORDINATES 7 SURFACE boundary segments Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 .0 135.0 200.0 135.0 2 200.0 135.0 237.0 160.9 3 237.0 160.9 250.0 170.0 4 250.0 170.0 428.0 240.0 5 428.0 240.0 468.0 245.0 6 468.0 245.0 510.0 275.0 7 510.0 275.0 700.0 300.0 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Unit Moist Sat. No. (pcf) (pcf) 1 115.0 115.0 Soil Unit Below Segment 1 1 1 1 1 1 1 Cohesion Friction Pore Pressure Intercept Angle Parameter Constant (psf) (deg) Ru (psf) 25.0 37.00 .000 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, Water Surface No. 1 *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water No. (ft) (ft) 1 .00 127.00 2 200.00 127.00 , 3 700.00 215.00 A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified. 100 trial surfaces will be generated and analyzed. 10 Surfaces initiate from each of 10 points equally spaced along the ground surface between x = 196.0 ft and x = 205.0 ft Each surface terminates between x = 240.0 ft and x = 280.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = .0 ft * * * * * DEFAULT SEGMENT LENGTH SELECTED BY XSTABL * * * * * 5.0 ft line segments define each trial failure surface. ANGULAR RESTRICTIONS : The first segment of each failure surface will be inclined within the angular range defined by : Lower angular limit := -45.0 degrees Upper angular limit := (slope angle - 5.0) degrees 5 218.23 143.19 6 222.56 145.69 7 226.78 148.36 8 230.89 151.20 9 234.89 154.21 10 238.76 157.38 11 242.50 160.70 12 246.10 164.17 13 249.55 167.78 14 252.32 170.91 * * ** Simplified BISHOP FOS = 1.256 * * ** The following is a summary of the TEN most critical surfaces Problem Description : 3944 - 002 -RO1 INITIAL CONDITIONS FOS Circle Center Radius Initial Terminal Resisting (BISHOP) x -coord y -coord x -coord x -coord Moment (ft) (ft) (ft) (ft) (ft) (ft -lb) 1. 1.256 158.75 251.22 123.32 200.00 252.32 1.928E +06 2. 1.268 175.86 221.77 90.07 200.00 249.06 1.491E +06 3. 1.270 140.49 285.76 161.53 202.00 255.20 2.303E +06 4. 1.280 180.17 216.75 82.86 203.00 247.19 1.095E +06 5. 1.288 103.48 338.58 225.30 200.00 255.22 2.798E +06 6. 1.296 178.71 211.94 79.05 202.00 241.66 8.025E +05 7. 1.297 124.37 315.00 194.05 205.00 255.85 2.239E +06 8. 1.301 137.79 308.15 183.67 201.00 265.38 4.644E +06 9. 1.303 160.38 273.65 142.32 205.00 263.10 3.223E +06 10. 1.306 164.13 231.93 103.05 201.00 241.89 8.854E +05 * * * END OF FILE * * * 11 -07 -94 0) O t F-- Z 3944 - 002 -R01 O - N N O - M (0 c0 o M O r` N 0 _ O _ O 0) O O 0 0 (0 'tna' M N v- (e) SIXd —A 0) (t) 1G. X XSTABL File: SMS -IN4 11 -07 -94 17:13 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * X S T A B L Slope Stability Analysis using the Method of Slices * Copyright (C) 1992 5 94 * Interactive Software Designs, * Moscow, ID 83843, U.S.A. * * * All Rights Reserved * * * * * * * * Ver. 5.005 94 A 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Problem Description : 3944 - 002 -R01 INITIAL SEGMENT BOUNDARY COORDINATES Ah =0.ig 7 SURFACE boundary segments Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 .0 135.0 200.0 135.0 2 200.0 135.0 237.0 160.9 3 237.0 160.9 250.0 170.0 4 250.0 170.0 428.0 240.0 5 428.0 240.0 468.0 245.0 6 468.0 245.0 510.0 275.0 7 510.0 275.0 700.0 300.0 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit No. Unit Weight Moist Sat. (pcf) (pcf) 1 115.0 Cohesion Intercept (psf) Soil Unit Below Segment 1 1 1 1 1 1 1 Friction Pore Pressure Angle Parameter Constant (deg) Ru (psf) 115.0 25.0 37.00 .000 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, Water Surface No. 1 *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water No. (ft) (ft) 1 .00 127.00 2 200.00 127.00 3 700.00 215.00 A horizontal earthquake loading coefficient of .100 has been assigned A vertical earthquake loading coefficient of .000 has been assigned A SINGLE FAILURE SURFACE HAS BEEN SPECIFIED FOR ANALYSIS Trial failure surface is CIRCULAR, with a radius of 123.32 feet Center at x = 158.75 ; y = 251.22 ; Seg. Length = 5.00 feet The CIRCULAR failure surface was estimated by the following 14 coordinate points : Point x -surf y -surf No. (ft) (ft) 1 200.00 135.00 2 204.68 136.77 3 209.28 138.72 4 213.80 140.86 5 218.23 143.19 6 222.56 145.69 7 226.78 148.36 8 230.89 151.20 9 234.89 154.21 10 238.76 157.37 11 242.50 160.69 12 246.10 164.16 13 249.56 167.78 14 252.32 170.91 ******************** * * * * * * ** * * * * * * * * * * * * * * * * * * * * * ** SELECTED METHOD OF ANALYSIS: Simplified Bishop ******************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** ********* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** SUMMARY OF INDIVIDUAL SLICE INFORMATION ********* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Slice x -base y -base height width alpha beta 'weight (ft) (ft) (ft) (ft) (lb) 1 202.34 135.88 .75 4.68 20.70 34.99 405. 2 206.98 137.75 2.14 4.60 23.03 34.99 1132. 3 211.54 139.79 3.28 4.52 25.35 34.99 1706. 4 216.01 142.03 4.18 4.43 27.67 34.99 2130. 5 220.39 144.44 4.84 4.33 30.00 34.99 2409. 6 224.67 147.02 5.25 4.23 32.32 34.99 2549. 7 228.84 149.78 5.41 4.11 34.64 34.99 2558. 8 232.89 152.70 5.32 4.00 36.96 34.99 2444. 9 235.94 155.07 5.09 2.11 39.29 34.99 1235. 10 237.88 156.65 4.86 1.76 39.29 34.99 984. 11 240.63 159.03 4.41 3.74 41.61 34.99 1894. 12 244.30 162.43 3.58 3.60 43.93 34.99 1482. 13 247.83 165.97 2.51 3.46 46.26 34.99 998. 14 249.78 168.03 1.82 .44 48.58 34.99 93. 15 251.16 169.60 .86 2.32 48.58 21.47 230. SLICE INFORMATION ... continued : Slice Sigma c -value phi U -base U -top Q -top Delta (psf) (psf) (lb) (lb) (lb) 1 60.7 25.0 37.00 0. 0. 0. .00 2 180.0 25.0 37.00 0. 0. 0. .00 3 272.1 25.0 37.00 0. 0. 0. .00 4 338.9 25.0 37.00 0. 0. 0. .00 5 381.8 25.0 37.00 0. 0. 0. .00 6 402.4 25.0 37.00 0. 0. 0. .00 7 402.4 25.0 37.00 0. 0. 0. .00 8 383.4 25.0 37.00 0. 0. 0. .00 9 354.4 25.0 37.00 0. 0. 0. .00 10 337.9 25.0 37.00 0. 0. 0. .00 11 294.6 25.0 37.00 0. 0. 0. .00 12 228.2 25.0 37.00 0. 0. 0. .00 13 149.5 25.0 37.00 0. 0. 0. .00 14 99.4 25.0 37.00 0. 0. 0. .00 15 39.2 25.0 37.00 0. 0. 0. .00 For the single specified surface, Simplified BISHOP factor of safety = 1.034 Resisting Moment = 181.57E +04 ft -lb WARNING - This method is valid only if the failure surface approximates a circle n 0 ri 11 -07 -94 U) Z SOLDIER PILE WALL 3944 - 002 —R01 most critical surfaces, MINIMUM BISHOP FOS = 0 O O O 0 to co 00 M N (4a9J) SIXd_) O - M c0 O - Ln 0 O C) O XSTABL File: SMS -IN5 11 -07 -94 17:07 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** X S T A B L Slope Stability Analysis using the Method of Slices Copyright (C) 1992 6 94 Interactive Software Designs, Inc. Moscow, ID 83843, U.S.A. All Rights Reserved * * * * * * * * * * * * * * Ver. 5.005 94 6 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Problem Description : 3944 - 002 -RO1 SOLDIER PILE WALL SEGMENT BOUNDARY COORDINATES 7 SURFACE boundary segments Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 .0 135.0 236.9 135.0 2 236.9 135.0 237.0 160.9 3 237.0 160.9 250.0 170.0 4 250.0 170.0 428.0 240.0 5 428.0 240.0 468.0 245.0 6 468.0 245.0 510.0 275.0 7 510.0 275.0 700.0 300.0 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Unit Moist Sat. No. (pcf) (pcf) 1 115.0 115.0 Soil Unit Below Segment 1 1 1 1 1 1 1 Cohesion Friction Pore Pressure Intercept Angle Parameter Constant (psf) (deg) Ru (psf) 25.0 37.00 .000 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, Water Surface No. 1 *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water No. (ft) (ft) 1 .00 127.00 2 200.00 127.00 3 700.00 215.00 BOUNDARIES THAT LIMIT SURFACE GENERATION HAVE BEEN SPECIFIED UPPER limiting boundary of 2 segments: Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 236.9 120.0 236.9 135.0 2 236.9 135.0 237.0 160.9 A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified. 100 trial surfaces will be generated and analyzed. 10 Surfaces initiate from each of 10 points equally spaced along the ground surface between x = 150.0 ft and x = 200.0 ft Each surface terminates between x = 280.0 ft and x = 350.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = .0 ft * * * * * DEFAULT SEGMENT LENGTH SELECTED BY XSTABL * * * * * 8.0 ft line segments define each trial failure surface. ANGULAR RESTRICTIONS : The first segment of each failure surface will be inclined within the angular range defined by : Lower angular limit := -45.0 degrees Upper angular limit := (slope angle - 5.0) degrees Factors of safety have been calculated by the : SIMPLIFIED BISHOP METHOD * * * * * The following is a summary of the TEN most critical surfaces Problem Description : 3944 - 002 -R01 SOLDIER PILE WALL FOS Circle Center Radius Initial Terminal Resisting (BISHOP) x -coord y -coord x -coord x -coord Moment (ft) (ft) (ft) (ft) (ft) (ft -lb) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 1.801 1.805 1.806 1.810 1.810 1.814 1.818 1.818 1.825 1.825 224.24 228.33 109.66 166.67 330.55 3.867E +07 228.78 205.02 86.63 177.78 314.80 2.627E +07 222.02 242.59 123.63 161.11 339.83 4.723E +07 224.11 205.35 87.42 172.22 310.69 2.528E +07 223.60 189.45 71.17 177.78 294.72 1.654E +07 234.19 230.90 111.26 177.78 342.69 4.448E +07 223.96 244.43 126.20 161.11 344.47 5.160E +07 233.93 206.40 87.51 183.33 320.97 2.852E +07 235.38 232.52 113.26 177.78 345.82 4.726E +07 230.88 226.98 109.09 172.22 337.55 4.292E +07 * * * END OF FILE * * * 11 -07 -94 cD z 3944 - 002 -R01 V) CD 0 W_ CL J 1 1 1 1 1 1 0990 my-A 1 31 13i O a) 4- O tip V) — Q X O N N 0 — co 0 O) O G) O XSTABL File: SMS -IN6 11 -07 -94 17:11 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * X S T A B L * * * * * * * * * * All Rights Reserved * Slope Stability Analysis using the Method of Slices Copyright (C) 1992 $ 94 Interactive Software Designs, Inc. Moscow, ID 83843, U.S.A. * Ver. 5.005 94 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Problem Description : 3944 - 002 -R01 S.P. Wall Ah =0.2g SEGMENT BOUNDARY COORDINATES 7 SURFACE boundary segments Segment x -left y -left No. (ft) (ft) 1 2 3 4 5 6 7 .0 236.9 237.0 250.0 428.0 468.0 510.0 135.0 135.0 160.9 170.0 240.0 245.0 275.0 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Unit Moist Sat. No. (pcf) (pcf) 1 115.0 115.0 x -right y -right Soil Unit (ft) (ft) 236.9 135.0 237.0 160.9 250.0 170.0 428.0 240.0 468.0 245.0 510.0 275.0 700.0 300.0 Below Segment 1 1 1 1 1 1 1 Cohesion Friction Pore Pressure Intercept Angle Parameter Constant (psf) (deg) Ru (psf) 25.0 37.00 .000 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, Water Surface No. 1 *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water SUMMARY OF INDIVIDUAL SLICE INFORMATION ********* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Slice x -base y -base height width alpha beta weight (ft) (ft) (ft) (ft) (lb) 1 170.15 133.03 1.97 6.96 -29.58 .00 1579. 2 177.24 129.34 5.66 7.23 -25.40 .00 4707. 3 181.65 127.31 7.69 1.60 -21.22 .00 1413. 4 185.38 125.86 9.14 5.86 -21.22 .00 6157. 5 192.14 123.55 11.45 7.65 -17.04 .00 10069. 6 197.98 121.92 13.08 4.04 -12.85 .00 6076. 7 201.88 121.03 13.97 3.76 -12.85 .00 6040. 8 207.71 120.00 15.00 7.91 -8.67 .00 13643. 9 215.66 119.08 15.92 7.98 -4.49 .00 14599. 10 223.64 118.75 16.25 8.00 -.31 .00 14953. 11 231.63 119.00 16.00 7.98 3.87 .00 14691. 12 236.26 119.36 15.64 1.27 8.05 .00 2293. 13 236.95 119.45 28.50 .10 8.05 89.78 328. 14 240.27 119.92 43.27 6.55 8.05 34.99 32576. 15 246.77 121.08 46.66 6.45 12.23 34.99 34625. 16 250.68 121.93 48.34 1.37 12.23 21.47 7588. 17 255.20 123.21 48.84 7.67 16.41 21.47 43098. 18 262.78 125.75 49.28 7.49 20.59 21.47 42441. 19 270.16 128.83 49.10 7.26 24.77 21.47 41013. 20 277.29 132.44 48.29 7.00 28.95 21.47 38873. 21 284.14 136.57 46.86 6.70 33.14 21.47 36101. 22 290.60 141.12 44.84 6.22 37.32 21.47 32072. 23 293.78 143.55 43.67 .14 37.32 21.47 720. 24 296.85 146.25 42.17 5.99 41.50 21.47 29059. 25 302.64 151.76 38.94 5.59 45.68 21.47 25028. 26 308.01 157.68 35.13 5.16 49.86 21.47 20835. 27 312.94 163.98 30.77 4.70 54.04 21.47 16625. 28 317.40 170.62 25.89 4.21 58.22 21.47 12542. 29 321.36 177.56 20.50 3.71 62.40 21.47 8737. 30 324.80 184.78 14.64 3.18 66.58 21.47 5352. 31 327.71 192.23 8.33 2.64 70.76 21.47 2526. 32 329.79 198.84 2.54 1.53 74.94 21.47 445. SLICE INFORMATION ... continued : Slice Sigma c -value phi U -base U -top Q -top Delta (psf) (psf) (lb) (lb) (lb) 1 366.0 25.0 37.00 0. 0. 0. .00 2 932.6 25.0 37.00 0. 0. 0. .00 3 1171.0 25.0 37.00 0. 0. 0. .00 4 1296.4 25.0 37.00 446. 0. 0. .00 5 1363.8 25.0 37.00 1721. 0. 0. .00 6 1385.7 25.0 37.00 1313. 0. 0. .00 7 1429.9 25.0 37.00 1471. 0. 0. .00 8 1348.5 25.0 37.00 4047. 0. 0. .00 9 1246.2 25.0 37.00 5168. 0. 0. .00 10 1121.6 25.0 37.00 6011. 0. 0. .00 11 977.2 25.0 37.00 6572. 0. 0. .00 12 871.7 25.0 37.00 1093. 0. 0. .00 13 2230.5 25.0 37.00 86. 0. 0. .00 14 3787.2 25.0 37.00 5669. 0. 0. .00 15 3976.2 25.0 37.00 5654. 0. 0. .00 16 4155.2 25.0 37.00 1183. 0. 0. .00 17 4059.4 25.0 37.00 6539. 0. 0. .00 18 3994.5 25.0 37.00 5957. 0. 0. .00 19 3897.2 25.0 37.00 5093. 0. 0. .00 20 3769.2 25.0 37.00 3951. 0. 0. .00 21 3612.2 25.0 37.00 2539. 0. 0. .00 22 3428.4 25.0 37.00 863. 0. 0. .00 23 3411.6 25.0 37.00 0. 0. 0. .00 24 3132.3 25.0 37.00 0. 0. 0. .00 25 2737.6 25.0 37.00 0. 0. 0. .00 26 2325.0 25.0 37.00 0. 0. 0. .00 27 1902.5 25.0 37.00 0. 0. 0. .00 28 1479.5 25.0 37.00 0. 0. 0. .00 29 1066.8 25.0 37.00 0. 0. 0. .00 30 677.2 25.0 37.00 0. 0. 0. .00 31 326.4 25.0 37.00 0. 0. 0. .00 32 65.9 25.0 37.00 0. 0. 0. .00 For the single specified surface, Simplified BISHOP factor of safety = 1.229 Resisting Moment = 361.26E +05 ft -lb WARNING - This method is valid only if the failure surface approximates a circle 11-07-94 3944 - 002 -R01 WALL WITHOUT EMBEDMENT (D 11 0 0 0 z N V v 4- L. N D U L U .1L�^ O E 0 1 O O O O Lc) co M (199J) SIXV-A O XSTABL File: SMS -IN7 11 -07 -94 17:48 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * X S T A B L * * * * Slope Stability Analysis * * using the * * Method of Slices * * * * Copyright (C) 1992 a 94 * * Interactive Software Designs, Inc. * * Moscow, ID 83843, U.S.A. * * * * All Rights Reserved * * * * Ver. 5.005 94 a 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Problem Description : 3944 - 002 -RO1 WALL WITHOUT EMBEDMENT SEGMENT BOUNDARY COORDINATES 7 SURFACE boundary segments Segment No. 1 2 3 4 5 6 7 x -left y -left (ft) (ft) .0 236.9 237.0 250.0 428.0 468.0 510.0 135.0 135.0 160.9 170.0 240.0 245.0 275.0 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Unit Moist Sat. No. (pcf) (pcf) 1 115.0 115.0 x -right (ft) y -right (ft) 236.9 135.0 237.0 160.9 250.0 170.0 428.0 240.0 468.0 245.0 510.0 275.0 700.0 300.0 Soil Unit Below Segment 1 1 1 1 1 1 1 Cohesion Friction Pore Pressure Intercept Angle Parameter Constant (psf) (deg) Ru (psf) 25.0 37.00 .000 .0 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, Water Surface No. 1 *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water No. (ft) (ft) 1 .00 127.00 2 200.00 127.00 3 700.00 215.00 BOUNDARIES THAT LIMIT SURFACE GENERATION HAVE BEEN SPECIFIED UPPER limiting boundary of 1 segments: Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 236.9 135.0 237.0 160.9 A critical failure surface searching method, using a random technique for generating CIRCULAR surfaces has been specified. 100 trial surfaces will be generated and analyzed. 10 Surfaces initiate from each of 10 points equally spaced along the ground surface between x = 190.0 ft and x = 230.0 ft Each surface terminates between x = 260.0 ft and x = 300.0 ft Unless further limitations were imposed, the minimum elevation at which a surface extends is y = .0 ft * * * * * DEFAULT SEGMENT LENGTH SELECTED BY XSTABL * * * * * 6.0 ft line segments define each trial failure surface. ANGULAR RESTRICTIONS : The first segment of each failure surface will be inclined within the angular range defined by : Lower angular limit := -45.0 degrees Upper angular limit := (slope angle - 5.0) degrees Factors of safety have been calculated by the : * * * * * SIMPLIFIED BISHOP METHOD * * * * * The most critical circular failure surface is specified by 17 coordinate points Point x -surf y -surf No. (ft) (ft) 1 207.78 135.00 2 213.63 133.69 3 219.60 133.02 4 225.60 132.99 5 231.56 133.61 6 237.43 134.86 7 243.13 136.73 8 248.60 139.20 9 253.77 142.25 10 258.58 145.83 11 262.98 149.91 12 266.92 154.43 13 270.36 159.35 14 273.24 164.62 15 275.54 170.16 16 277.24 175.91 17 278.18 181.08 * * ** Simplified BISHOP FOS = 1.256 * * ** The following is a summary of the TEN most critical surfaces Problem Description : 3944 - 002 -RO1 WALL WITHOUT EMBEDMENT FOS Circle Center Radius Initial Terminal Resisting (BISHOP) x -coord y -coord x -coord x -coord Moment (ft) (ft) (ft) (ft) (ft) (ft -lb) 1. 1.256 222.86 188.81 55.88 207.78 278.18 4.565E +06 2. 1.332 223.21 199.24 66.07 207.78 287.61 6.775E +06 3. 1.351 222.89 204.15 70.78 207.78 291.35 7.740E +06 4. 1.358 213.50 209.84 78.45 190.00 287.83 7.977E +06 5. 1.364 229.88 185.95 51.70 221.11 281.34 4.870E +06 6. 1.364 230.16 184.48 50.30 221.11 280.32 4.668E +06 7. 1.370 225.71 190.35 58.18 207.78 283.43 6.045E +06 8. 1.374 214.46 202.86 72.13 190.00 283.85 7.166E +06 9. 1.377 220.77 196.75 65.51 198.89 284.92 6.976E +06 10. 1.384 221.53 208.68 75.90 203.33 294.34 9.014E +06 * * * END OF FILE * * * 11 -07 -94 to N 39 (1) O - N 3 N 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 O O O O �d M N co tV �" (199J) SIX\ -) XSTABL File: SMS -IN8 11 -07 -94 17:50 *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * X S T A B L * * Slope Stability Analysis * using the * Method of Slices * * Copyright (C) 1992 94 * Interactive Software Designs, Inc. * Moscow, ID 83843, U.S.A. * * All Rights Reserved * * Ver. 5.005 94 1237 * *********** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Problem Description : 3944 - 002 -RO1 WALL W/O EMBED Ah =0.2g SEGMENT BOUNDARY COORDINATES 7 SURFACE boundary segments Segment x -left y -left x -right y -right Soil Unit No. (ft) (ft) (ft) (ft) Below Segment 1 .0 135.0 236.9 135.0 1 2 236.9 135.0 237.0 160.9 1 3 237.0 160.9 250.0 170.0 1 4 250.0 170.0 428.0 240.0 1 5 428.0 240.0 468.0 245.0 1 6 468.0 245.0 510.0 275.0 1 7 510.0 275.0 700.0 300.0 1 ISOTROPIC Soil Parameters 1 Soil unit(s) specified Soil Unit Weight Cohesion Friction Pore Pressure Water Unit Moist Sat. Intercept Angle Parameter Constant Surface No. (pcf) (pcf) (psf) (deg) Ru (psf) No. 1 115.0 115.0 25.0 37.00 .000 .0 1 1 Water surface(s) have been specified Unit weight of water = 62.40 (pcf) Water Surface No. 1 specified by 3 coordinate points *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** PHREATIC SURFACE, *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Point x -water y -water No. (ft) (ft) 1 .00 127.00 2 200.00 127.00 3 700.00 215.00 A horizontal earthquake loading coefficient of .200 has been assigned A vertical earthquake loading coefficient of .000 has been assigned BOUNDARIES THAT LIMIT SURFACE GENERATION HAVE BEEN SPECIFIED UPPER limiting boundary of 1 segments: Segment x -left y -left x -right y -right No. (ft) (ft) (ft) (ft) 1 236.9 135.0 237.0 160.9 A SINGLE FAILURE SURFACE HAS BEEN SPECIFIED FOR ANALYSIS Trial failure surface is CIRCULAR, with a radius of 55.88 feet Center at x = 222.86 ; y = 188.81 ; Seg. Length = 6.00 feet The CIRCULAR failure surface was estimated by the following 17 coordinate points : Point x -surf y -surf No. (ft) (ft) 1 207.78 135.00 2 213.64 133.69 3 219.60 133.02 4 225.60 132.99 5 231.57 133.61 6 237.43 134.86 7 243.13 136.73 8 248.60 139.21 9 253.77 142.25 10 258.58 145.84 11 262.98 149.91 12 266.92 154.44 13 270.35 159.36 14 273.24 164.62 15 275.54 170.16 16 277.24 175.92 17 278.17 181.08 ******************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** SELECTED METHOD OF ANALYSIS: Simplified Bishop ******************** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** ********* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** SUMMARY OF INDIVIDUAL SLICE INFORMATION ********* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** Slice x -base y -base height width alpha beta weight (ft) (ft) (ft) (ft) (lb) 1 210.71 134.35 .65 5.86 -12.58 .00 440. 2 216.62 133.36 1.64 5.96 -6.42 .00 1126. 3 222.60 133.01 1.99 6.00 -.27 .00 1374. 4 228.58 133.30 1.70 5.97 5.89 .00 1166. 5 234.23 134.18 .82 5.33 12.04 .00 504. 6 236.95 134.76 13.19 .10 12.04 89.78 152. 7 237.22 134.81 26.24 .43 12.04 34.99 1310. 8 240.28 135.80 27.40 5.70 18.19 34.99 17962. 9 245.87 137.97 29.14 5.47 24.35 34.99 18316. 10 249.30 139.62 29.89 1.40 30.50 34.99 4810. 11 251.89 141.14 29.60 3.77 30.50 21.47 12833. 12 256.18 144.04 28.38 4.81 36.66 21.47 15711. 13 260.78 147.87 26.37 4.40 42.81 21.47 13346. 14 264.95 152.18 23.70 3.94 48.97 21.47 10737. 15 268.64 156.90 20.43 3.43 55.12 21.47 8060. 16 271.80 161.99 16.58 2.88 61.28 21.47 5497. 17 274.39 167.39 12.20 2.30 67.43 21.47 3230. 18 276.39 173.04 7.34 1.70 73.59 21.47 1430. 19 277.70 178.50 2.40 .93 79.74 21.47 257. SLICE INFORMATION ... continued : Slice Sigma c -value phi U -base U -top Q -top Delta (psf) (psf) (lb) (lb) (ib) 1 98.3 25.0 37.00 0. 0. 0. .00 2 210.6 25.0 37.00 0. 0. 0. .00 3 230.0 25.0 37.00 0. 0. 0. .00 4 178.1 25.0 37.00 0. 0. 0. .00 5 76.1 25.0 37.00 0. 0. 0. .00 6 1293.3 25.0 37.00 0. 0. 0. .00 7 2576.9 25.0 37.00 0. 0. 0. .00 8 2494.0 25.0 37.00 0. 0. 0. .00 9 2458.6 25.0 37.00 0. 0. 0. .00 10 2334.1 25.0 37.00 0. 0. 0. .00 11 2311.2 25.0 37.00 0. 0. 0. .00 12 2042.2 25.0 37.00 0. 0. 0. .00 13 1735.7 25.0 37.00 0. 0. 0. .00 14 1412.1 25.0 37.00 0. 0. 0. .00 15 1082.8 25.0 37.00 0. 0. 0. .00 16 760.6 25.0 37.00 0. 0. 0. .00 17 461.4 25.0 37.00 0. 0. 0. .00 18 204.7 25.0 37.00 0. 0. 0. .00 19 24.3 25.0 37.00 0. 0. 0. .00 For the single specified surface, Simplified BISHOP factor of safety = .953 Resisting Moment = 417.31E +04 ft -lb WARNING - This method is valid only if the failure surface approximates a circle CASTELLO LAND CO INC 4730 32ND AVE S. SEATTLE, WA 98118 LEVITZ FURNITURE CORP 212 HIGH ST POTTSTOWN, PA 19464 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 HAROLD R IVERSON 1252 GREEN LANE BURLINGTON, WA 98233 MIKAMI MASAO PO BOX 256 DUBLIN, OH 43017 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S VAUGHN WY STE 204 AURORA, CO 80014 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 LEVITZ FURNITURE CORP 212 HIGH ST POTTSTOWN, PA 19464 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PACIFIC NORTHWEST GROUP A 3131 S. VAUGHN WY STE 204 AURORA, CO 80014 PARKWAY PROPERTIES INC 720 3RD AVE SUITE 1700 SEATTLE, WA 98104 i^— s —"I P.-- Y s "CVs 1 1994 DEVELOPMENT ENVIROBUSINESS, INC. PHASE II - LIMITED SUBSURFACE INVESTIGATION 17501 Southcenter Parkway Tukwila, Washington November 12, 1993 Prepared for. Mr. John Hatfield Vice President Lennar Partners Nations Bank Plaza, Suite 3500 600 Peachtree Street Atlanta, Georgia 30308 TABLE OF CONTENTS LETTER OF TRANSMITTAL 1.0 INTRODUCTION 2.0 SUMMARY OF FINDINGS 3.0 SITE DESCRIPTION 3.1 LOCATION FIGURE 1 SITE LOCUS 3.2 ZONING 3.3 UTILmES 3.4.1 Water 3.4.2 Heat 3.4.3 Sewer 3.4 STORAGE TANKS FIGURE 2 SITE SCHEMATIC 3.5 PREVIOUS INVESTIGATIONS 4.0 REGIONAL DESCRIPTION 4.1 REGIONAL LAND USE 4.2 TOPOGRAPHY 4.3 GEOLOGY 4.4 HYDROLOGY/HYDROGEOLOGY 1 2 3 4 5 8 5.0 SUBSURFACE INVESTIGATION 9 5.1 SOIL SAMPLING AND ANALYSIS 5.1.1 Soil Borings 5.1.2 Soil Characterization 5.1.3 Soil Screening • 5.1.4 Analytical Results: Soil 5.2 MONITORING WELL INSTALLATION 5.2.1 Monitoring Well Locations 5.2.2 Monitoring Well Construction • 5.3 GROUNDWATER SAMPLING AND ANALYSIS 5.3.1 Groundwater Flow 5.3.2 Groundwater Sampling • 5.3.3 Analytical Results: Groundwater FIGURE 3 GROUNDWATER ELEVATIONS 15 6.0 CONCLUSIONS 7.0 LIMITATIONS 16 18 TABLE OF CONTENTS (Conti ATTACHMENT A- LIMITATIONS PHOTOGRAPH ADDENDUM APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX A- ENVIRONMENTAL BASELINE ASSESSMENT, ARTHUR D. LITTLE, INC., APRIL 29, 1993 B -LETTER REPORT, HERRERA ENVIRONMENTAL CONSULTANTS, OCTOBER 29, 1993 C- BORING LOGS D- ANALYTICAL RESULTS E -HNu PHOTOIONIZATION DETECTOR SPECIFICATIONS AND SCREENING PROCEDURES F- MONITORING WELL REQUIREMENTS G- GROUNDWATER FLOW CALCULATIONS H- SAMPLING PROCEDURES ENVIROBUSI•ESS ENVIRONMENTAL CONSULTAW S 701 CONCORD AVENUE CAMBRIDGE, MA 02138 (617) 868 - 4321 FACSIMILE (617) 868 - 3132 Mr. John Hatfield Vice President Lennar Partners NationsBank Plaza, Suite 3500 600 Peachtree Street, N.E. Atlanta, Georgia 30308 R.E. LW Real Estate.Investments, L.P. Dear Mr. Hatfield: November 12, 1993 In accordance with the Proposal for additional work dated October 13, 1993 ENVIROBUSINESS, INC. ( ENVIROBUSINESS) is pleased to submit our Phase 11 - Limited Subsurface Investigation (Investigation) on a property located at 17501 South Center Parkway, Tukwila, Washington (the Site). This Investigation was performed in accordance with the Washington Administrative Code (Chapters 173 -200 and 173 -340). The purpose of the Investigation was to further investigate the findings of the Environmental Baseline Assessment (Assessment) prepared by Arthur D. Little, Inc. (ADL) on April 29, 1993 (see Appendix A) and a visual inspection of the Site interior performed by Herrera Environmental Consultants (Herrera) on October 21, 1993 (see Appendix B). The performed scope of work of the Investigation is based on findings from the Assessment prepared by ADL, the inspection by Herrera and existing conditions at the Site. The conclusions of this Investigation are based on work performed by ENVIROBUSINESS including: field screening of subsurface soils obtained from four soil borings drilled at the Site on October 22 and October 23, 1993 and laboratory analysis of soils and groundwater from the monitoring well installations. Conclusions in this Investigation are based in part on information from the Assessment prepared by ADL and the inspection by Herrera. Respectfully submitted, Kevin R. O'Malley Senior Consultant ENVIROBUSINESS, INC. Project 093 -1765 17501 Southcatter Parkway, Tukwila, WA November 12, 1993 1.0 INTRODUCTION The purpose of this Phase II- Limited Subsurface Investigation (Investigation) was to determine the condition of the groundwater and soils and establish baseline conditions at the Site. The subsurface investigation included the following. • Four soil borings were drilled, with subsequent installation of a groundwater monitoring well in each of these borings (see Appendix C). • Soil samples were field screened with an HNu Photoionization Detector (PID) to detect the presence of Volatile Organic Compounds (VOCs) in soils encountered during the soil borings. • Selected soil samples in which VOCs were detected above 5 parts per million (ppm) above background during the field screening process were submitted to a state certified laboratory, and tested for the presence of VOCs. No screened soil samples exceeded this limit and no samples were submitted for VOC analysis. • One soil sample per boring was submitted to a state certified laboratory for Total Petroleum Hydrocarbon (TPH) analysis by the infrared (IR) method, and for analysis for 13 priority pollutant metals (PPM -13). • Monitoring well headspace was screened for volatile organic compounds using the PID. • Groundwater samples from monitoring wells were submitted for laboratory analyses to detect the presence of VOCs using EPA Method 624, TPH by the IR method and for PPM -13. • Groundwater flow direction and hydraulic head gradient were calculated from groundwater elevations measured in the four wells and a topographic survey referenced to an arbitrary datum. 2 • ENVIROBUSINESS, INC. Project 093 -1765 17501 Southcenter Parkway. Tukwila, WA November 12, 1993 2.0 SUMMARY OF FINDINGS Field data and laboratory analysis of groundwater samples collected by ENVIROBUSINESS from the four monitoring wells installed at the Site and soil samples collected from their respective borings, indicated the following: • No evidence of a release of Oil or Hazardous Materials (OHM) was detected or observed at the Site. However metals were detected in both soil and groundwater samples. • Field screening of soil samples did not detect organic vapors in excess of background levels of 0.5 -1.0 parts per million (ppm). No soil samples were sent for VOC analysis. No TPH were detected above detection limits in laboratory analysis of soil samples submitted. • Concentrations of metals in soils were all below soil cleanup levels except for cadmium. Cadmium concentrations exceeded the cleanup levels for soil (cadmium cleanup level based on plant protection) but were below the industrial soil cleanup level (based on protection of groundwater) in all samples submitted. Cadmium was below detection limits in all groundwater samples (see Section 5.1.4 of this Investigation). . • No VOCs or TPH were detected in any of the groundwater samples submitted for. analysis. Copper, Lead, Zinc, Antimony, and Mercury were detected in groundwater samples submitted for analysis. Lead was detected at a concentration of 0.010 milligrams per litre (mg/L) in the groundwater sample obtained from monitoring well EB -1. This concentration exceeds the State of Washington Department of Ecology (DOE) Groundwater Cleanup Level of 0.005 mg/L, but was below the DOE Water Quality Standard for Groundwater of 0.050 mg/L (see Section 5.3.3 of this Investigation). The complete Toxikon report is included .as Appendix D. • Groundwater was calculated to be flowing across towards the northeast to east - northeast on a bearing of 038° to 066° relative to magnetic north. It is likely that the hydraulic head gradient in the area northwest of the building is affected by a dewatering well located in that area. The hydraulic head gradient for the rest of the Site area was ENVIROBUSINESS. INC. Project 093 -1765 17501 Southcaner Parkway, Tukwila, WA November 12, 1993 calculated at 0.0657 (units are dimensionless). This equates to a head drop of one foot every 15.2 feet. • The Site is improved with a nine -story office building and associated parking lots. The Site is located in a commercial area within the City of Tukwila, WA. • Empty 55- gallon drums reported by ADL in April, 1993 were not observed at the Site. A 55- gallon drum containing propylene glycol and water was observed in a chemical storage container located behind the building. Other chemicals included algaecides and descalers and cardboard boxes labeled as containing MEK. No stains were observed. A storage container located adjacent to the Satellite Dish Enclosure contained some electrical supplies. 3.0 4ITE DESCRIPTION 3.1 LOCATION According to the Des Moines, WA Quadrangle, U.S.G.S. Topographic Map, the Site is located at 47 °26'45" north latitude, 122 °15'40" west longitude. The Universal Transverse Mercator (UTM) coordinates are 5,254,762 niN and 555,710 mE. The Site consists of six acres of land, approximately 10% of which is occupied by the Parkway Plaza building. The Parkway Plaza building until recently operated as an office building for Boeing and was used as a project center for classified goverment work. The building is currently vacant. The Site is located at 17501 Southcenter Parkway, Tukwila, WA (see Figure 1, Site Locus, which depicts the Site on a portion of the U.S.G.S: Des Moines, WA Quadrangle 7.5 minute series Topographic Map). Access to the Site is from the west side of Southcenter Parkway between Strander Boulevard and 180th Street. The Site is abutted by an abandoned railroad spur, woodland and Interstate 5 to the west, Winners restaurant to the north, Azteca restaurant and Levitz furniture to the south and Southcenter Parkway to the east. Parkway 4 i rTLE 11TACOMA • IATIONAL AIRPORT GEO SITE LOCATION ll� 2 A portion of the Des Moines, WA U.S.GS. Quadrangle SCALE: 1:24,000 I 1/2 1 Mile 1 Figure 1 Site Locus 17501 Southcentral Parkway Tukwila, WA ENVIROBUSINESS, INC. (617) 868-4321 N t 5 ENVIROBUSINESS, INC. Project 093 -1765 17501 Soothe-enter Parkway, Tukwila, WA November 12, 1993 Plaza shopping mall is located on the . opposite side of Southcenter Parkway. Figure 2, Site schematic is a computer generated plan of the Site and the immediate vicinity. 3.2 ZONING According to ADL the site is zoned as M -1, light industrial, within the Tukwila City Limits and the building is designated as a Type B -2 building (business, office etc.). Seismically the Site is located in a Zone 3 area, designated as stable. The Site is not located in.the 100 -year floodplain. 3.3 UTILITIES • 3.3.1 Water According to the ADL Assessment water is supplied by the City of Tukwila. 3.3.2 Heat According to the Herrera report, space hearing and cooling is via a hydronic heat pump system. Electronic units located on the roof of the building heat or chill water which is then circulated throughout the building. 3.3.3 Sewer According to the ADL Assessment, waste water enters the City of Tukwila sewer system and is treated at the Metro Treatment plant. • 3.4 STORAGE TANKS The ADL Assessment indicated that according to the building plan, a small day tank was located in the generator room on the roof of the building. However, Herrera observed a 140 - gallon day tank in a mechanical room in the basement, located on the western side of the building. Fill and vent pipes for this tank were observed adjacent to the loading dock. 1 1 1 1 1 1 Chemical/ Storage Container/ 1 1 Dumpsterl 1 1 1 1 1 1 1 1 1 1. 1 1 1 1 Railway Line Easement Former Drum Storage Area Dewatering well Parking Lot EB -3 Loading Dock Area Site Building Satellite Dish Enclosure Storage Container 4EB -2 Parking Lot +EB-4 Winners Restaurant Parking Lot Entrance Driveway Parking Lot Azteca Restaurant Legend Well Location • • Fill and Vent Pipe Southcenter Parkway NOT TO SCALE Figure 2 Site Schematic 17501 Southcentral Parkway Tukwila, WA ENVIROBUSINESS, INC. (617) 868 -4321 ENVIROBUSINESS, INC. Project 093 -1765 17501 Soudtcattet Parkway. Tukwila, WA November 12. 1993 3.5 PREVIOUS INVESTIGATIONS An Environmental Baseline Assessment, dated April 29, 1993 was performed by ADL and a follow up Letter Report, dated October 29 was performed by Herrera. Both of these reports are contained in Appendices of this Investigation. Herrera noted that the photograph and medical laboratories referred to by ADL were not at the Site. They also listed hazardous chemicals at the Site, these included propylene glycol, algaecides and other descalers. They also noted a sealed cardboard box with a shipping label identifying its contents as MEK. These chemicals were all stored in the chemical storage container located on the west side of the building. The chemicals were still at the Site on October 22, 1993. The empty 55 -gallon drums reported by ADL were not observed at the Site during this Investigation. 4.0 REGIONAL DESCRIPTION 4.1 REGIONAL LAND USE The Site is located on the western margin of a valley containing the Green River/Duwamish River. According to the ADL report, the valley was formerly farmland until its development in the 1970's for warehouse use. In the 1980's the area was developed as a retail center with the construction of the shopping mall. 4.2 TOPOGRAPHY • The Site is located at the western boundary of the Green/Duwamish River valley at an elevation of approximately 25 feet above mean sea level. The topography of the Site is essentially flat sloping gradually towards the east. A steep hill rises abruptly on the western edge of the Site to an elevation of 482 feet (as indicated by a U.S.G.S. benchmark) located approximately one mile west of the Site. The highest point of elevation in the area is an unnamed hill, located approximately 11/4 mile northwest of the Site, with an elevation of approximately 510 feet above mean sea level (see Figure 1, Site Locus). 8 ENVIROBUSINESS. INC. Project 893 -1765 17501 Southcetter Parkway, Tukwila. WA November 12, 1993 4.3 GEOLOGY According to the U.S.G.S. Geological Map of the Des Moines Quadrangle (GQ -159), dated 1962, the Site is underlain by alluvium. Rock outcrops comprised of laminated clay and siltstone were observed at the base of the hillside abutting the Site to the west. Alluvium underlies the valley floor with Kame terrace deposits composed of Glacio-fluvial sand and gravel forming the hill slope west of the Site. 4.4 HYDROLOGY/HYDROGEOLOGY The Site is located in the Green River / Duwamish River drainage basin, with the Green River located approximately 1/2 mile southeast of the Site. The Green River flows north and its confluence with the Duwamish River is approximately two miles northeast of the Site. The Duwamish River discharges into Puget Sound (an inlet of the Pacific Ocean) approximately ten miles north of the Site. Sensitive receptors in the area include the Green River and its associated tributaries. Groundwater flow direction at the Site is discussed in Section 5.3.1 of this Investigation. 5.0 SUBSURFACE INVESTIGATION 5.1 SOIL SAMPLING AND ANALYSIS 5.1.1 Soil Borings A total of four soil borings (EB -1, EB -2, EB -3 and EB -4) were installed on October 22 and 23, 1993, using hollow stem augers to average depths of approximately five feet below the observed water table. Standard penetration tests (SPT) were performed in the test borings at five foot intervals or as shown on the test boring logs. Soil samples were collected from split -spoon samplers, which were driven approximately one and a half feet into undisturbed soils by a 140 -pound drop hammer in accordance with the standard method ASTM D- 1586 -84. Soil boring logs are presented in Appendix C, Boring Logs. Monitoring wells were installed in all of the borings at the locations shown in Figure 2. 9 ENVIROBUSINESS, INC. Project #93 -1765 17501 Southcenter Parkway. Tukwila, WA November 12, 1993 5.1.2 Soil Characterization Subsurface soils were characterized and their description entered in the boring logs (see Appendix C). EB-1 EB -1, located on the west side of the building in the vicinity of the former hazardous materials storage area, was drilled to a depth of twenty feet. EB -1 was spudded through asphalt and encountered approximately four feet of coarse brown gravelly sand with pebbles and some clay. This was followed to a depth of eight feet by dark grey -brown coarse, poorly sorted sand with clay. From eight to 10'6" moist blue -green medium to coarse sand with much clay was encountered. From 10'6" to 21'6" grey, clay silt was encountered. This unit varied from tight, silty clay to sandy silt and was moist throughout the drilled horizons. Monitoring well EB -1 was installed in this boring and screened from five to 20 feet. 2 EB -2 was spudded through asphalt and was located south of the building near the satellite dish. EB -2 encountered approximately. three feet of dry "fill" of coarse grey poorly sorted sand with clay and gravel/pebbles. This was followed from three to 16'6" of moist to wet, grey, poorly sorted, coarse angular sand with clay and some gravel. Monitoring well EB -2 was installed in this boring and screened from five to 15 feet. EB -3 was located in the parking lot in front of the northeast side of the building. EB -3 was spudded through asphalt and encountered yellow grey, clay silt with some lithic fragments, to a depth of eight feet. This was followed from eight to 21'6" by coarse brown - grey, angular, poorly sorted sand with lithic fragments. Monitoring well E13-3 was installed in this boring and screened from 10 to 20 feet. EB-4 EB -4 was located in the parking lot in front of the southeast side of the building. EB -4 was spudded through asphalt and encountered gravelly fill to a depth of approximately four feet. This was followed from four to six feet by silty sand and from six to 11 feet by grey, silty clay. From 11 to 19'6" feet, medium coarse, angular, poorly sorted sand with clay was 10 ENVIROBUSINESS. INC. Project 993 -1765 17501 Southcauar Parkway, Tukwila. WA November 12. 1993 encountered Monitoring well EB-4 was installed in this boring and screened from 9'6" to 19'6" feet. . 5.1.3 Soil Screening During soil boring activities, split spoon soil samples were collected and screened with an NNu photoionization detector (PID) for the presence of VOCs. (See Appendix E for a complete description of the PID field screening of soils and for PID readings of screened soil samples). Background PID readings of 0.5 -1.0 were detected at the site. The soil samples were screened upon extraction from the split spoon sampler and a second time after ten to fifteen minutes to give any VOCs a chance to volatilize. No screened soils exhibited PID readings in excess of 5 ppm above background and therefore no soil samples were submitted for further analysis. 5.1.4 Analytical Results: Soil Based on the field screening of soils, no samples were submitted for VOC analysis. One sample per boring was sent to a laboratory for TPH analysis by infrared spectroscopy (EPA method 9073). One soil sample per boring was submitted for PPM -13 analysis (EPA method 3005). A complete report of these analyses can be found in Appendix D of this Investigation. Based on the analytical report prepared by Toxikon, TPH was below detection limits in all soil samples. Analytical results of all soil samples are summarized in Table 1. Cadmium exceeds the Method A Cleanup Levels for soil of 2.0 mg/JA but are within the Industrial Soil Levels of 10.0 mg/kg. It must be noted that the Industrial Soil Cleanup Levels are based on protection of groundwater and the Soil Cleanup Levels based on plant protection. The Site is a commercial lot and completely paved except for some landscaped areas adjacent to the building. ENVIROBUSINESS. INC. Project N93 -1765 17501 Southcenter Parkway. Tukwila, WA November 12. 1993 Table 1 • Analytical Results: Soils (Results in mg/kg - parts per million (ppm)) Analyte Detection Limit Soil/Industrial Soil- Method A Cleanup Levels Soil Boring Identification EB -1 EB -2 EB -3 EB-4 TPH 40.0 200.0/200.0 ND ND ND ND Metals • Silver 1.3 ND ND ND ND Cadmium 0.66 2.0/10.0 2.79' 2.11' 2.42' 8.33' Chromium 0.66 100.0/500.0 37.8 33.6 37.1 68.9 Copper 0.66 26.6 18.0 18.2 37.8 Nickel 2.6 39.1 37.9 43.2 70.0 Lead 1.0 250.0/1000.0 5.0 2.75 2.85 4.98 Zinc 0.39 40.0 38.6 40.6 102 Arsenic 1.50 20/200.0 6.30 4.22. 3.75 5.39 Selenium 0.5 3.22 4.41 3.41 2.96 Beryllium 0.26 • ND ND ND 1.10 Antimony 0.5 ND ND ND ND Thallium 0.5 ND ND ND ND Mercury • 0.324 _ (inorg) 1.0/1.0 ND _ ND ND ND Note: ND = Not Detected. Bold indicates concentrations in excess of cleanup levels. `Denotes concentrations in excess of clean up levels based on plant protection, but below cleanup levels based on groundwater protection. 5.2 MONITORING WELL INSTALLATION 5.2.1 Monitoring Well Locations All four soil borings were completed as monitoring wells. Monitoring well EB -1 is located in the parking lot outside the west side of the building and. approximately 35 feet topographically downgradient (northeast) from the former chemical storage area located A behind the building. A water well used to dewater the building foundation, is located 65 feet northeast of EB -1. Monitoring well EB -2 is located south of the building and approximately 40 feet east of the satellite dish enclosure. EB -3 is located in the parking lot in front of the northeast corner of the building. EB -4 is located in the parking lot in front of the southeast corner of the building. 12 ENVIROBUSINESS. INC. Project 493-1765 17501 Southcettter Parkway. Tukwila. WA November 12, 1993 5.2.2 Monitoring Well Construction Permanent monitoring wells were installed in borings EB -1, EB -2, EB -3 and EB -4 in order to obtain groundwater samples for laboratory analysis and to determine groundwater head elevations. The wells penetrated approximately five feet below the saturated zones or the water table where encountered. The wells consist of 10.0 to 15.0 feet of 2.0 inch diameter, 0.10 inch slotted schedule 40 PVC threaded pipe (screen) and 5.0 to 10.0 feet of 2.0 inch diameter, schedule 40 PVC riser pipe. The wells were fully screened across the water table (saturated zones). Silica sand was placed around the slotted screen section of the wellpoint to a level approximately 3.0 foot above the screen to act as a filter pack. A 2.0 foot bentonite clay seal was placed above the sand to act as a seal to prevent surface runoff from entering the well. The well was backfilled with bentonite pellets to a depth of approximately two feet below grade. A two inch expansion plug was put in the riser to seal the well and a non - locking monument well cover box was installed flush to the ground surface to cap the well. The monument well cover was secured with concrete. Monitoring wells were developed prior to sampling using a surge block (a full bailer) to eliminate bridged sand and remove fines, such as clay particles, from the sand filter pack. All monitoring wells were tagged with a State of Washington Department of Ecology "Unique Well" identification plate which was secured around the riser inside the Monument well cover. EB -1 was designated Unique Well# ABB -128, EB -2 was designated Unique Well# ABB -129, EB -3 was designated Unique Well# ABB -130 and EB-4 was designated Unique Well# ABB -131. The State of Washington Department of Ecology monitoring well requirements are included in Appendix E, Monitoring Well Requirements. 5.3 GROUNDWATER SAbIPLING AND ANALYSIS • 5.3.1 Groundwater Flow Monitoring wells EB -1, EB -2, EB -3 and EB-4 were sampled on October 25, 1993. The depth of the groundwater at the Site was determined using an electronic depth gauge. The relative ground surface elevations were established during a Site survey referenced to an arbitrary datum of 100 feet and subsequent groundwater elevations were calculated using this data. The groundwater elevation of EB -1 was determined to be 86.66 feet, EB -2 was determined to be 89.92 feet, EB -3 was determined to be 83.76 feet, and EB -4 was 13 ENVIROBUSINESS, INC. Project *934765 17501 Southceztter Parkway, Tukwila, WA November 12, 1993 determined to be 83.90 feet. Due to its proximity to the dewatering well it is believed that the groundwater elevation measured at EB -1 was artificially low. Groundwater flow calculated from all wells indicated that flow was to the northeast to east - northeast. Depending on which well elevations were used for flow calculations the direction of flow varied from 038° to 066° relative to magnetic north. Head gradient also varied from 0.0177 (units are dimensionless) equating to one foot head drop every 56.5 feet to 0.0657 (one foot head drop every 15.2 feet). Ignoring the elevation in EB -1 due to its proximity to the dewatering well, the headgradient across the eastern part of the Site appears to be 0.0657 on a bearing of 066 °. Groundwater flow calculations are presented in Figure 3, Groundwater Elevations and Appendix G of this Investigation. 5.3.2 Groundwater Sampling Groundwater samples were obtained from the four monitoring wells according to Sampling Procedures outlined in Appendix H. The well headspace was measured using the PID as soon as the well was first uncapped. Monitoring wells were purged a minimum of three well volumes with a dedicated disposable bailer to ensure a representative groundwater sample. All groundwater samples were placed in laboratory prepared containers and stored at approximately 4 °C pending State certified• analyses by Toxikon for TPH using the IR method (EPA Method 418.1), VOCs (EPA Method 624) and priority pollutant metals (EPA method 3005, 200.7 and 245.1 Mercury). TPH samples were preserved with sulphuric acid (H2SO4), VOC samples were preserved with hydrochloric acid (HC1) and metals were filtered and acidified upon receipt by the laboratory. 5.3.3 Analytical Results: Groundwater Based on the analytical report prepared by Toxikon, No VOCs were detected in the four groundwater samples submitted. TPH was below detection limits in all samples submitted for analysis. Laboratory analyses of groundwater samples, well headspace readings from the PID, the State of Washington Department of Ecology Water Quality Standards for Groundwaters (Chapter 173 -200 WAC) and the Groundwater Method A Cleanup Levels (Chapter 173 -340 WAC) are summarized in Table 2. A complete report of these analyses can be found in Appendix D of this Investigation. 14 1 1 Chemical1 Storage Container . 1 1 Dumpsterl 1 Railway Line Easement Former Drum Storage Area Dewatering well EB -1 EL 86.60' Parking Lot EB -3 winners Restaurant Parking Lot 83.76' Loading Dock • Site Building a o�. a'�C44.4ei6C. Entrance Driveway 4to Q Satellite Dish Enclosure Storage Container EB -2 EL 83.92' Parking Lot �EB-4 EL 83.90' Parking Lot Azteca Restaurant Lend 4' Well Location • Fa and Vent Pipe Southcenter Parkway Figure 3 Groundwater Elevation NOT TO SCALE 17501 Southcentral Parkway Tukwila, WA ENVIROBUSINESS, INC. (617) 868 -4321 15 ENVIROBUSINESS, INC. Project #93 -1765 17501 Southcaua Parkway, Tukwila, WA November 12, 1993 Table 2 - Analytical Results: Groundwater Analyte . Concentration • Detection Limit , Groundwater quality criteria /Method A cleanup levels Soil Boring Identification EB-1 (ABB -128) EB-2 (ABB -129) EB -3 (ABB -130) EB-4 (ABB -131) PID -Well ppm 0.1 , 1.0 1.0 1.0 1.0 Ikactspace TPH mg/L (ppm) 1.0 NS /1.0 ND ND ND ND VOCs Metals µg/L (ppb) mg/L (ppm) ND ND ND ND Silver 0.020 0.05/NS ND ND ND ND Cadmium • 0.010 0.01/0.005 ND ND ND ND Chromium 0.010 0.05 /0.050 ND ND ND ND Copper 0.010 1.0/NS ND ND 0.013 0.010 Nickel 0.040 NS/NS ND ND ND ND Lead 0.050 0.05 /0.005 0.010 ND ND ND Zinc 0.0060 5.0/NS ND 0.010 ND 0.025 Arsenic 0.10 0.00005 /0.005 ND ND ND ND Selenium 0.25 0.01/NS ND ND ND ND Beryllium . 0.0040 NS/NS ND ND ND ND Antimony 0.15 NS/NS ND ND ND 0.009 Thallium 0.30 NS/NS ND ND ND ND Mercury 0.0005 0.002/0.002 0.001 ND 0.001 0.001 Note: ND = Not Detected Bold indicates concentrations in excess of cleanup levels. From Table 2 it can be seen that of the analytes detected, lead, detected in EB -1, was above the Method A cleanup level but below the groundwater quality criteria. 6.0 CONCLUSIONS Based on the information assembled for the Phase 1I - Limited Subsurface Investigation, ENVIROBUSINESS discovered no evidence of a release of OHM at the Site. Concentrations of metals in soils were all below soil cleanup levels except for cadmium Cadmium concentrations exceeded the cleanup levels for soil (cadmium cleanup level based on plant protection) but were below the industrial soil cleanup level (based on protection of groundwater) in all samples submitted. Cadmium was below detection limits in all groundwater samples. 16 ENVIROBUSINESS. INC. Project 093 -1765 ' 17501 Southceuter Parkway, Tukwila. WA November 12, 1993 No VOCs or TPH were detected in any of the groundwater samples submitted for analysis. Copper, Lead, Zinc, Antimony, and Mercury were detected in groundwater samples submitted for analysis. Lead was detected at a concentration of 0.010 mg/L in the groundwater sample obtained from monitoring well EB -1. This concentration exceeds the State of Washington Department of Ecology Groundwater Cleanup Level of 0.005 mg/L, but was below the Water Quality Standard for Groundwater of 0.050 mg/L Monitoring well EB -1 was located approximately 65 feet from a dewatering well. It is possible that groundwater elevations in EB -1 are artificially low due to drawdown effects of the dewatering well. Groundwater flow calculated from all wells indicated that flow was to the northeast to east - northeast. Depending on which well elevations were used for flow calculations the direction of flow varied from 038° to 066° relative to magnetic north. Head gradient also varied from 0.0177 (one foot head drop every 56.5 feet) to 0.0657 (one foot head drop every 15.2 feet). Ignoring the elevation in EB -1 due to its proximity to the dewatering well, the headgradient across the eastem part of the Site appears to be 0.0657 on a bearing of 066 °. The contaminants detected at the Site all occur naturally and do not appear to be as a result of current or past releases and/or land use practices at the Site. The Site is in an industrial area (zoned as light industrial) and completely paved except for some landscaped areas. Soil contamination is below the Industrial Soil Cleanup Guidelines and it is likely that metal concentrations are within background ranges. Antimony standards were not listed, however the EPA Phase V maximum contaminant level for public water supplies for antimony is 0.006 mg/L. There are no private drinking water wells at the Site and water is provided by the city of Tukwila. It is unlikely therefore, that groundwater at the Site would be used for drinking in the future. The conclusions of this Investigation are based on the laboratory results of the soil and groundwater samples and site data obtained on October 22, 23 and 25, 1993 and information provided in the ADL and Herrera reports dated April 29, 1992 and October 29, 1993 respectively. 17 ENVIROBUSINESS, INC. Project 193 -1765 17501 Southcenter Parkway, Tukwila. WA November 12, 1993 7.0 LIMITATIONS The observations in this Phase II - Limited Subsurface Investigation are valid on the date of the investigation and are made under the conditions noted in the Investigation, our Proposal for additional work dated October 13, 1993 and our Agreement for Environmental Services, dated October 8, 1993, all of which are integral parts of this Investigation. • This Investigation has been prepared by the staff of ENVIROBUSINESS for Mr. John Hatfield of Lennar Partners in accordance with accepted geotechnical practices using that degree of skill and care exercised for similar projects under similar conditions by competent environmental consultants. No other warranty, express or implied, is made. It has been a pleasure to perform this Investigation. Please feel free to call George Naslas, Lawrence Boise or John Roddy if there are any questions or if we may be of further assistance. Sincerely, ENVIROBUSINESS, INC. George D. Naslas Project Manager ATTACHMENT A LIMITATIONS 1. The observations described in this Report were made under the conditions stated herein. The conclusions presented are based solely upon the services described, and not on scientific tasks or procedures beyond the scope of described services or the time and budgetary constraints imposed by Client. The work described in this Report was carried out in accordance with terms and conditions in our Authorization Letter and Agreement for Environmental Services regarding the Site, which are incorporated herein by references. 2. In preparing this Report, ENVIROBUSINESS, INC. ( ENVIROBUSINESS) has relied on certain information provided by state and other referenced parties, and on information contained in the files of federal, state and/or local agencies available to ENVIROBUSINESS at the time of the assessment. Although there may have been some degree of overlap in the information provided by these various sources, ENVIROBUSINESS did not attempt to independently verify the accuracy or completeness of all information reviewed or received daring the course of these Environmental Services. 3. Observations were made of the Site and of structures on the Site as indicated within the Report. Where access to portions of the Site or to structures on the Site was unavailable or limited, ENVIROBUSINESS renders no opinion as to the presence of oil or hazardous materials (OHM) in that portion of the Site or structure. In addition, ENVIROBUSINESS renders no opinion as to the presence of OHM or the presence of indirect evidence relating to OHM where direct observation of the interior walls, floor, or ceiling of a structure on a Site was obstructed by objects or coverings on or over these surfaces. No representations concerning insulating material is expressed or implied. 4. ENVIROBUSINESS did not perform testing or analyses to determine the presence or concentration of asbestos, radon, or lead at the Site unless specifically stated otherwise in the Report. Similarly, no investigation of dust or air quality was conducted unless specifically stated otherwise in the Report. 5. The purpose of this Ripon is to assess the physical characteristics of the Site with respect to the presence of OHM in the environment. No specific attempt was made to determine the compliance of present or past owners or operators of the Site with federal, state, or local laws or regulations (environmental or otherwise). 6. The conclusions and recommendations contained in this Report are based in part, where noted, upon the data obtained from a limited number of soil or water samples obtained from widely - spaced subsurface explorations. The nature and extent of variations between these explorations may not become evident until further exploration. If variations or other latent conditions then appear evident, it will be necessary to reevaluate the conclusions and recommendations of this Report. 7. Any water level readings made in test pits, borings, and/or observation/monitoring wells were made at the times and under the conditions stated in the Report. However, it must be noted that fluctuations in the level of groundwater may occur due to variations in rainfall and other factors different from those prevailing at the time measurements were made. 8. Except as noted in the Report, no quantitative laboratory testing was performed as part of the assessment. Where such analyses have been conducted by an outside laboratory, ENVIROBUSINESS has relied upon the data provided, and has not conducted an independent evaluation of the reliability of this data 9. The conclusions and recommendations contained in this Report are based in part (where noted) upon various types of chemical data and are contingent upon their validity. This data has been reviewed and interpretations made in the RepB1t. As indicated in the Report, some of this data may be preliminary "screening" level data, and should be confirmed with quantitative analyses if more specific information is necessary. Moreover, it should be noted that variations in the types and concentrations of contaminants and variations in their flow paths may occur due to seasonal water table fluctuations, past disposal practices, the passage of time, and other factors. Should additional chemical data become available in the future, these data should be reviewed, and the conclusions and recommendations presented herein modified accordingly. 10. Chemical analyses may have been performed for specific constituents during the course of these Environmental Services, as described in the Report. However, it should be noted that additional chemical constituents not searched for during the current study may be present in soil and/or groundwater at the Site. 11. Any qualitative or quantitative information regarding the Site, which was not available to ENVIROBUSINESS at the time of this assessment may result in a modification of the representations made herein. 12. It is acknowledged that ENVIROBUSINESS' judgements shall not be based on scientific or technical test or procedures beyond the scope of the Services or beyond the time and budgetary constraints imposed by Client. It is acknowledged further that ENVIROBUSINESS' conclusions shall not rest on pure science but on such considerations as economic feasibility and available alternatives. Client also acknowledges that, because geologic and soil formations are inherently random, variable, and indeterminate in nature, the Services and opinions provided under this Agreement with respect to such Services, are not guaranteed to be a representation of actual conditions on the Site, which are also subject to change with time as a result of natural or man -made processes, including water permeation. In performing the Services, ENVIROBUSINESS shall use that degree of care and skill ordinarily exercised by environmental consultants or engineers performing similar services in the same or similar locality. The standard of care shall be determined solely at the time the Services are rendered and not according to standards utilized at a later date. The Services shall be rendered without any other warranty, expressed or implied, including, without limitation, the warranty of merchantability and the warranty of fitness for a particular purpose. 13. Client and ENVIROBUSINESS agree that to the fullest extent permitted by law, ENVIROBUSINESS shall not be liable to Client for any special, indirect or consequential damages whatsoever, whether caused by ENVIROBUSINESS' negligence, errors, omissions, strict liability, breach of contract, breach of warranty or other cause of causes whatsoever. 14. In connection with its performance under the conditions and terms in Authorization letter or agreement, ENVIROBUSINESS shall use reasonable care to locate underground structures, such as pipes, cables and tanks, in exploration and testing areas at the Site. ENVIROBUSINESS shall not be liable for damage to or interference with underground structures, including geological structures, which have not been brought to ENVIROBUSINESS' attention by Client or the owner of the Site or which are incorrectly located on plans or information furnished to ENVIROBUSINESS by Client, by the owner of the Site of by Dig -Safe. 15. ENVIROBUSINESS shall not be liable for any contractor's or subcontractor's failure to use due care for the maintenance of safety at the Site or failure to comply with the Occupational Health and Safety Act of 1970, any regulations promulgated thereunder, and/or any state, county or municipal law or regulation of similar import. 16. Client acknowledges and agrees that ENVIROBUSINESS is not responsible or liable for the condition of the Site, now existing or hereafter arising or discovered. ENVIROBUSINESS does not, by its execution or performance of the Services, assume any liability or responsibilities with respect to said conditions. Client acknowledges that the use of equipment by ENVIROBUSINESS or its contractors and subcontractors may alter or damage the grade, subgrade, vegetation, buildings, structures, and/or improvements on or about the Site. Client hereby releases, indemnifies and holds ENVIROBUSINESS harmless from and against a any and all liabilities and damages of any nature arising out of the performance of the Services at the Site, except to the extent that such damage is caused by the negligent acts or omissions of ENVIROBUSINESS, its employees or agents. ENVIROBUSINESS agrees that the Services will be provided in accordance with generally accepted engineering practices employed by firms providing similar services under the same circumstances and conditions. ENVIROBUSINESS will endeavor to limit damage to the Site during the performance of services under this Agreement. All Site restoration shall be the responsibility of Client. PHOTOGRAPH ADDENDUM PHOTOGRAPH ADDENDUM Photo #1: • This is a photograph of the Parkway Plaza building looking west. The • photograph is taken from Southcenter Parkway. PHOTOGRAPH ADDENDUM Photo #2: This is a photograph of EB -1 located behind the Site building. Photo #3: This is a photograph of the location of EB -2 looking north. Note the fenced enclosure used to house the satellite dish. PHOTOGRAPH ADDENDUM Photo #4: This is a photograph the satellite dish and its enclosure located south of the building. The container in the foreground contains miscellaneous electrical supplies. Photo #5: This is a photograph of a soil sample from boring EB-1. Note the different clay-silt horizons. PHOTOGRAPH ADDENDUM Photo #6: This is a photograph of EB -3 located in the parking lot northeast of the building. PHOTOGRAPH ADDENDUM Photo #7: This is a photograph of EB -4 located in the parking lot southeast of the building. PHOTOGRAPH ADDENDUM Photo #8: This is a photograph of a soil sample taken from EB -3. Note the clay and the sand horizons. PHOTOGRAPH ADDENDUM Photo #9: This is a photograph of the dumpster located behind the building. Notice the railway easement and the hillside rising steeply behind the Site. Photo #10: This is a photograph of the chemical storage container located behind the building. PHOTOGRAPH ADDENDUM Photo #11: This is a photograph of the 55- gallon drum located in the storage container. Photo #12: This is a photograph of other chemicals located in the storage container. APPENDIX A ENVIRONMENTAL BASELINE ASSESSMENT ARTHUR D. LITTLE, INC. APRIL 29, 1993 Artful. D Little o99 Environmental Baseline Assessment - Parkway Plaza, Tukwila, • Washington Confidential Volume 1 Report and Appendices Report .to EnviroBusiness April. 29, 1993 Arthur D. Little, Inc. Center for Environmental Assurance Acom Pant Cambridge, Massachusetts 02140 . Reference 43655 Table of Contents Confidential I. Introduction A. Scope of Work B. Approach C. Organization of Report D. Facility Access II. Description of Facility A. History B. General Description• C. Infrastructure 1 1 2 2 2 3 3 3 4 III. General Environmental Discussion 5 A. Wastewater Control 5 B. Air Emissions Control 5 C. Non - hazardous and Hazardous Waste Disposal 5 D. Asbestos 5 E. Polychlorinated BiphenyLs 5 F. Tanks 5 G. Soil and Groundwater 5 H. Dcinldng Water 5 I. Spill Control 6 J. Paint 6 K. Radon 6 Appendices Appendix A Site Map Appendix B Permits Appendix C Inventory of Wells Appendix D Agency Contacts Appendix E Inventory of Tanks Appendix F Inventory of Pits and Sumps Appendix G Database Search Sampling Protocols A. Drinking Water B. Paint C. Radon D. Asbestos Ar hhi r D Little I. Introduc,_...n Confidential A. Scope of Work Arthur D. Little, Inc. (ADL) was contracted by EnviroBusiness, Inc. to conduct environmental assessments of twenty-seven (27) facilities. This report prepared on behalf of EnviroBusiness, Inc., reflects the assessment performed at the Parkway Plaza Building, 17501 South Central Parkway, Tukwila, Washington. The actual physical inspection was conducted on April 23, 1993. The material in this report reflects Arthur D: Little's best judgment in light of the information available to it at the time of preparation. The purpose of this work was to identify and assess current environmental conditions at the Parkway Plaza Building that could result in current or future liabilities and to develop a "baseline" report that documents those conditions as of the date of our visit to the site. The scope of work included the following functional environmental areas: • Wastewater Control • Air Emissions Control • Non - hazardous and Hazardous Waste Disposal • Asbestos • Polychlorinated Biphenyls • Tanks • Soil and Groundwater • Drinking Water • Spill Control • Paint • Radon Where possible, single samples were taken of paint and tap water to measure the lead content. Radon detectors were also placed where possible at the facility and areas that appeared to contain friable asbestos were also sampled. The taking of test samples for lead paint, lead in water, radon and asbestos were limited to single locations at each property and the results of such tests can not be construed as indication of conditions on the property as a whole. In the case of the radon samples, the responsibility for securing the canister at the proper time and sending it to the laboratory was left to the facility personnel. The scope of work did not include any sampling and analysis of groundwater, surface water, or soils. In assessing this facility, we followed a revised version of Arthur D. Little's protocol that had been customized to ensure that information called for in our teens of reference with EnviroBusiness, Inc. would be collected. This was done to the extent that the information could be obtained in a reasonable manner within the constraints imposed upon us by the facility, its owners/operators, regulatory agencies, or lack of available information. Our focus was on conditions that could lead to unwanted adverse impacts on the environment related to the functional areas listed above. "Conditions" could include matters of potential non-compliance with applicable laws and regulations, although we were not requested, nor did we perform a compliance audit. Arthur D Little I. Introduce _n Confidential B. Approach This assessment was carried out by Arthur D. Little personnel in accordance with ADL's site assessment protocol and generally accepted environmental assessment practices. At the facility, to the extent they cooperated, we met with the appropriate personnel to gain an understanding of facility history and operations, environmental control systems, any known environmental issues,.and prior uses of the facility and surrounding property. We inspected the facility to observe the operations, equipment, chemical and hazardous material storage, and environmental control systems that were in place. Where we were able within the constraints imposed and based upon the construction date of the facility, we conducted sampling of drinking water, paint, radon, and any sources suspected of being friable asbestos. We also reviewed relevant docurents that were made available to us and looked for landowners in the vicinity who have had operations on their sites that may have hada potential for causing contamination through migration to the facility. We visited relevant local regulatory and governmental agencies to confirm information that we had received or to obtain additional information. We also reviewed documents and maps related to current and prior ownership of the properties in order to help determine historical usage of the property. C. Organization of Report This report contains a general description of the facility followed by information regarding facility environmental conditions. Specific conditions we observed that may resiilt in some current or future environmental liability are reported. The appendices contain detailed information not easily integrated into the body of the report. This tends to be an exception report, but wherever it is important to the information needs of the terms of reference, we have noted the absence of any observed potential liabilities. D. Facility Access Arthur D. Little did not receive permission from the owner/operator of Parkway Plaza to conduct a complete physical site inspection. Because of the nature of the operations at the property, we were able to gain limited access to those parts of the facility open to the public. --- - I1. Description of Facility Confidential A. History The Parkway Plaza Building was designed in 1978 and constructed for occupancy by Boeing. Boeing leased the facility in part to carry out classified assignments for DOD until recently when it relocated most of its work force to Kent, Washington. The building remains a secured area with restricted access. All information was collected through interviews with the Planning and Engineering Department of the City of Tukwila and a . review of available documents. Additional information was gathered from telephone interviews with Boeing environmental personnel. B. General Description The Parkway Plaza Building until recently operated as an office building and project center for classified government work. The structure was designed to accommodate 1810 people and designated as a Type B -2 building. The property is zoned as M -1 within the Tukwila City limits. • The central part of the building is composed of 9 floors, a basement and a penthouse. In addition there are 7 floors of additional office space at either end of the structure. It was equipped with a medical laboratory and an X -ray facility, and contained a cafeteria, film processing and reproduction facilities. A large delivery bay and docking area is located to the rear of the building. The building parking lot contains 1095 spaces, has access to South Central Parkway at the front of the structure, and is contiguous with the lots from the restaurants located to the North and South of the property. The building is situated on the western edge of the 6 acre property and occupies approximately 10% of the site. The property, which is not in the 100 -year floodplain area, is located on the western margin of the river valley occupied by the Green River/Duwamish River. The valley which was formerly farm land was developed in the early 1970s for warehouse use. In the 1980s, the area experienced a second transition and is presently occupied by a large shopping mall and retail area. In some instances the warehouse structures have been converted to retail stores and retain the spur service' offered by Union Pacific Railroad. The property is abutted on the east by Interstate 5, on the west by South Central Parkway, on the south by Winners Restaurant, and on the north by Azteca Restaurant.' An easement on the eastern edge of the property was recently occupied by Union Pacific, which operated a spur line to a Levitz Furniture Factory outlet located to the south of Azteca Restaurant. The tracts were removed last year when rail service to the factory ceased. The cross streets are Strander Boulevard to the north and south 180th Street on the south. Seismically, the site is located in a Zone 3 area and is stable. Recently, Boeing has conducted an environmental survey of the facility, and is presently in the process of restoring the building to its original condition. The Boeing environmental survey was not made available to us. .0.,.43at.0.4126 3 /Irtlur D Little 3 I1. Oescripti,... of Facility C. Infrastructure Confidential 1. Heating and Cooling Systems The cooling system is composed of a tower, located on the roof of the penthouse, pumps and pipe. No cooling water discharges were noted in the plans filed with the City of Tukwila (Permit #1549). 2. Potable Water Potable water is distributed by the City of Tukwila, which is supplied by the City of Seattle. 3. Sanitary Water Sanitary waste water enters the City of Tukwila POTW and is treated at the Metro Treatment plant 4. Fire Water The entire facility is equipped with fire sprinklers. 5. Tanks • The facility has no underground or above ground storage tanks with the exception of a small day tank located in the generator mom on the roof of the building. The building plant did not indicate the exact size of the tank. 6. Electrical Equipment The facility is supplied with electrical power from buried utilities and a large step -down transformer located at the rear of the building. Puget Sound Electric owns the transformer equipment. 7. Chemicals Used The facility used propylene glycol, propane and "dangerous" chemicals as evident by the waste streams located to the rear of the building. Depot stores of hazardous chemical were maintained in a small storage shed located near the solid waste dumpster. In addidon, a 20 -foot storage container of unknown contents was also located at the rear of the building near the loading area. Arthur D1 Little I11. General bsivironmental Discussion A. Wastewater Control Confidential 1. Sanitary Wastewater Sanitary sewage was generated from laboratories and various hand washing operations. According to the plans for the structure, sinks from the medical laboratory, and kitchen also emptied into the sanitary waste water system. No reclamation equipment or holding tanks were used. Sanitary sewage is discharged to the City of Tukwila Public Works sanitary sewer system where it is transported to the Metro sewage treatment facility before discharge into Puget Sound. 2. Stormwater Storm water at the facility consists of road, roof and parking lot runoff which empties into the stonmwater drainage system. Runoff from the Interstate 5 is collected in to 2 culverts and transported down the hill toward the western edge of the property where it enters into the stormwater drain system. Storm water eventually flows into the Duwamish River. 8. Air Emissions Control The facility did not generate significant levels of air pollutants. According to the plans it does not have any air pollution control devices. The laboratory•has exhaust vents as does the generator. C. Non - hazardous and Hazardous Waste Disposal There are at least 3 major types of observable solid waste streams generated by Boeing. These include sanitary trash, wood pallets, and empty chemical drums. There are probably more, but without access to either the facilities or maintenance personnel, further confirmation is not possible. Debris from the building is collected in a 40 -yard dumpster and emptied by Seatac Disposal twice weekly into a transfer facility where it is deposited into the Cedar Hill Landfill. It is unknown whether any sorting took place to separate recyclable paper products from the waste or whether spent batteries or metals were likewise separated. The building places wood pallets in piles at the rear of the building. Approximately, 50 wood pallets were observed during the tirne of the visit. Twenty empty 55 -gallon drums were also observed stacked between the dumpster and the chemical storage shed. The contents are unknown, but it is possible that the building's cooling system might have been recharged recently. D. Asbestos Since the building was completed in 1978, there is no friable asbestos present. However, Boeing was aware that asbestos was a component of the floor tiles. Arthur 11 Little III. General L..gironmental Discussion Confidential E. Polychlorinated Bfphenyfs Since the building was completed within the last 15 years, no polychlorinated biphenyls were used in the transformer equipment. The building plans contained no transformers, and the building was serviced with underground utilities and a step -down transformer located at the back of the building. F. Tanks No fuel storage tanks are present, with the exception of a small day tank located in the generator room according to the plans for the building. G. Soil and Groundwater No remedial action has been taken on the property or in the immediate area. Prior to its development the area was in pasture. Development of the area into warehouses brought a railroad spur past the property, which has recently been removed. The roadbed is still in place on the easement. Please refer to the ERIIS Report in Appendix G for available information on underground storage tanks within a mile radius. H. Drinking Water The facility receives its drinking water from the City of Tukwila. The city distributes water supplied to it by the City of Seattle, as Tukwila does not treat the water itself. Because we were denied access to the site, no samples were taken. I. SpIII Control The facility contained no quantities of oils, solvents, paints or soaps indoors. There were no floor drains noted in the plans for several of the rooms in the basement or receiving areas. There was no containment area with the possible exception of the dangerous chemicals shed on the rear of the building. J. Paint The building was constructed in the late 1970s. As such, it is possible that the structure has lead- containing paint. Because we were denied access to the site, no paint samples were taken. K. Radon Because we were denied access to the building, no radon samples were taken. Artlur D Little Appendix A Site Map Confidential Shoppi Across Azt.ca • Restaurant g Mall arkway AeM(red 104119 yinoS Parking Lot Satellite Dish rel • 0 ■ • A Parking Lot cnn 0 • o INFRINW • — Winners Restaurant • ■ 9 • 0 • PREPARED FOR: EnviroBusiness DATE: Apr111993 SCALE: Not to scale DWG. NO.: amm.43655.dwg.4/93 TITLE South Central Parlcway Tukwila, WA Facility — Layout Arthur D Little Appendix e Permits The property maintains no known environmental permits. Confidential Appendix C Inventory of Wells There are no known drinking water wells on the property. Confidential Appendix G' Agency Contacts I. A. Name Jack Pace Senior Planner 11. A. Name Robin Tisclunark Associate Engineer 111. A. Name Steven Ryan Environmental Assessment B. Summary of. Findings Confidential Agency, Address & Phone Department of Community Development City of Tukwila 6300 South Center Boulevard Tukwila, Washington 98188 206 -431 -3686 Agency, Address & Phone Public Work Engineering City of Tukwila 6300 South Center Boulevard Tukwila, Washington 98188 208 - 433 -0179 Agency, Address & Phone Boeing Corporation Parkway Plaza Building Tukwila, Washington. 206 - 773 -3076 We had a brief conversation with Steven Ryan.. Mr. Ryan failed to return our call and failed to provide us a copy of the Boeing environmental survey. IV. A. Name Tom Sargent Arthur D Little Agency, Address & Phone Seatac Disposal Commercial Accounts 206 - 872 -7220 Appendix E' Inventory of Tanks There are no known underground storage tanks on the property. Confidential Appendix F Inventory of Pits and Sumps There were no pits and sumps indicated on the building plan. Confidential Appendix G Database Search Confidential A search of the following databases found no violations for this site: • Comprehensive Environmental Response, Compensation and Liability Act Information System • Civil and Judicial Actions • Federal Superfund Potentially Responsible Parties/Superfund Enforcement Tracking System • Facility Index System • National Priority List • National Priority List Site Descriptions • Records of Decisions • Resource Conservation and Recovery Information System/Hazardous Waste Data Management System • Toxic Chemical Release Inventory ENVIRONMENTAL RISK INFORMATION & IMAGING SERVICES RADIUS REPORT REPORT NUMBER: 21845 STATE: WA LATITUDE: 47.477163 LONGITUDE: - 122.268450 ZIP CODES SEARCHED: 98168 98188 98178 98055 RADIUS DATABASE (MILES1 el9oerty property -1/16 1/16 -1/2 112-1 �, ZJP CODE CITY/COUNTY NPL 1.000 NO 0 0 0 0 0 CERCLIS 1.000 NO 0 0 0 8 0 TRI 1.000 NO 0 0 0 6 0 RCRIS TS 1.000 NO 0 0 0 1 0 RCRIS_LG 1.000 NO 0 • 0 • 2 12 0 RCRIS_SG 1.000 NO 0 2 9 16 0 DOCKET 1.000 NO 0 0 0 1 0 ERNS 1.000 NO 0 0 0 0 1 FINDS 1.000 NO 0 8 29 114 0 NUCLEAR NR NR NR NR NR 0 0 OPENDUMP NR NR NR NR NR 0 2 LUST 1.000 NO 0 0 1. 31 13 AMC 1.000 NO 0 0 3 10 0 RADIUS REPORTED SITES NOT•RADIUS REPORTED 0 STATE DATA IN PAPER FORMAT: UST, SWF 10 44 0 199 16 • Selection of PROPERTY records requires an accurate street address in the ERIIS job order. ZIP CODE and CITY /COUNTY sites are not radius reportable due to insufficient and /or inaccurate addresses reported by federal /state agency. These sites are reported within the study site zip code(s) and /or city /county and may be within the study site radius. These sites require further investigation to accurately assess proximity to the study site. A blank radius count indicates that the database was not searched by this radius per client instructions. NR in a radius or zip code count indicates that the database cannot be reported by this search criteria due to insufficient and /or inaccurate addresses reported by a federal /state agency. TOTAL ES 0 8 6 1 14 27 1 1 151 0 2 45 13 State data in paper format is sorted using the most specific secondary search criteria available (zip code, city, or county!. Arthur D Little 269 N W CC 0 0 33 2< I3 33 m 1, 0 0 00 0 YS 0 cote r H Sampling Protocols Confidential A. Drinking Water 1. This kit is designed to determine the lead content of the water after it has been standing in the pipes for at least six hours as well as the effect that allowing the water to run has on the lead content. 2. For the most meaningful results, collect the samples the first thing in the morning. The water should have been standing for at least six hours. 3. Label the bottles 0, 2, and 5 so that accurate interpretation can be made. 4. Remove the aerator from the faucet. Place the bottle labeled "0" under the cold water faucet, turn the water on gently and fill the container. 5. Allow the water to run for 2 minutes and fill the bottle labeled "2 ". This represents the "2 minute" sample. 6. Allow the water to run for 3 more minutes and fill the bottle labeled "5" this represents the "5 minute" sample. 7. Return the samples to the lab as soon as possible. B. Paint Reliability of results depend on proper sample collection. These procedures are taken from HUD guidelines and are based on standard methods for the collection of paint samples. Some materials that may be useful are: • Heat gun, two putty knives (narrow and wide blade), plastic zip lock bags or any small freezer strength storage bag, labels or tape, permanent marker, sharp thin -edge knife, mailing containers. Samples taken for analysis should be about 2 square inches or larger and.should contain all layers of paint down to the substrate. Inclusion of excessive amounts of substrate may affect the results. Record the location where the sample was taken on the reverse side of this form and on the sample collection bag. Be sure to attach a label identifying the sample. Do not under any circumstances place a business card, piece of scrap paper or material other than the paint sample inside the bag. .in.43u.ra..raa3 Arthur D Little Sampling Protocols. Confidential Three methods for sample collection are described: • Cut or punch 1. Place clear, pressure sensitive tape over an area slightly larger than the sample to be collected. Carefully measure and mark a 2" x 2" or larger area. 2. Cut down through all layers of paint with a punch, template, or sharp knife. 3. Remove the paint an thin layer of substrate beneath it using a sharp chisel having the same dimensions as a side of the measured area. • Cutting Using a sharp knife or scalpel, score a measured area of paint to a size at least 2" x 2 ". Attempt to lift the paint by sliding a thin blade along the score and underneath the paint Remove a section down to the wood or plaster making sure all layers are intact Avoid including wood, paper or plaster in the sample if results are to be reported in weight %. • Heat - Does not work well on plaster, works moderately well on concrete and exceptionally well on steel and wood. 1. Direct hot air from a heat gun about 4" to 6" from the surface while pressing the edge of a knife into the paint. Use gentle heat - do not overheat or cause smoking. 2. Altemately heat for a few seconds then cool for a few seconds while continuing to press the knife into the paint. 3. Use the knife to lift off the paint. Scrape the surface with the scraper to remove any residual paint. C. Radon 1. Identify the area where you will place the canister(s) on a map of the facility. Try to limit the placement to two canisters per facility. These should be placed in a basement level room, or if no basement exists on the ground floor. 2. Write "Date of Capping" and "Time of Capping" on the labels we have supplied to you separately. Leave areas for the facility employees to fill in this . information when they cap the canisters 48 hours later. These labels must be placed at the upper portion of the canister, on the same level with the bar code label. If the label is any lower on the canister, it will interrupt the measurement of radiation from the canister during analysis. Then immediately uncap and place the canister and the small green sign on a table top or some other area which is several feet above the floor. Artful'. D Little Sampling Protocols Confidential 3. Fill out a separate data sheet for each facility you visit, indicating the bar code numbers and the date and time of placement of the canisters used at each site, as well as the information indicated in the top box of the fora, and fax this form to the analysis laboratory. Accurate information on date and time of placement and recapping is critical to obtain valid results. 4. Instruct the employee to tightly recap the canister 48 hours later, writing the exact time and date of recapping on the label in the spaces you have left for them. Emphasize that it is important to record the exact time that the canister was recapped. The employees should then send the canisters using the Federal Express materials you have left with them for next morning delivery. D. Asbestos Sampling of material suspected to contain friable asbestos: 1. Record the location where the sample is taken on a site map and on the sample collection bag. Be sure to attach a label identifying the sample. • 2. Carefully cut a 2" by 2" section of the suspect material with a sharp knife or scalpel, down through all layers of the insulation. 3. Detach the sample from the substrate, and place in a zip lock bag. 4. Return the sample to the laboratory for analysis. Artful. 11 Little Attachment 3 Storage containers with unknown contents Chemical storage trash dumpster and barrels in rear of building Prepared For: Enviro/Business Date: April 1993 Reference Number: 43655 JTitle: Parkway Plaza Building Tukwila, Washington Arthir D Little Attachment 3 Front view of Parkway Plaza building Loading dock in rear of building Prepared For: Date: April 1993 Enviro/Business Reference Number: 43655 Title: Parkway Plaza Building Tukwila, Washington Arthir D Little LETTER REPORT HERRERA ENVIRONMENTAL CONSULTANTS, INC. OCTOBER 29, 1993 NOV 01 '93 04 :20PM SEATTLE WA HERRERA ENVIRONMENTAL CONSULTANTS October 29, 1993 John Roddy Enviro Business, Inc. 701 Concord Avenue Cambridge, MA 02138 Re: Parkway Plaza building inspection Dear Mr. Roddy: On October 21, 1993 Rob Harrison of Herrera Environmental Consultants conducted a walk- through building inspection of the Parkway Plaza building, 17501 South Central Parkway, Tukwila, Washington. The main objective of the inspection was to determine if any asbestos - containing materials or.other hazardous materials are present in the building. The building was used by the Boeing Company for office space, but currently is unoccupied. Mr. Harrison was accompanied during the inspection by Loren Laskow, representing property management. Mr. Laskow has managed the building for the. past 6 years. The building consists of three wings.. The middle wing is 9 stories high and both outside wings are 7 stories. Construction is monolithic concrete slab and beam with concrete columns. Permanent interior walls are finished with gypsum board. Mr. Laskow stated that approximately 90 percent of the walls are temporary movable partitions. The 'majority of the building consists of open landscape office space, with permanent- partitioned offices around the perimeter. The basement floor houses a cafeteria and both men's and women's locker and shower rooms. A mechanical room that houses an emergency generator and the fire sprinkler pump system also is located in the basement. The emergency generator is fed by an approximately 140 - gallon - /day tank,. which is suspended in the mechanical room above the generator. No underground storage tanks were found. Most of the suspended ceiling tiles have been removed. Approximately 30 percent of the building is unlighted. Space heating and cooling is accomplished by a hydronic heat pump system. 1414 oexter Electrical rooftop units heat or chill water that is circulated through the Avenue North building in polyvinyl chloride (PVC) piping. The piping intercepts randomly Suite 200 spaced heat exchangers where forced air is blown over coils to heat or cool Seattle the spaces. Only fiberglass insulation was found. Washington 98109 The only suspect asbestos- containing materials identified were several types of vinyl sheet flooring, floor and cove mastic, gypsum board (drywall), and :O6) 2814604 joint compound. Most of these materials are in good condition. However, FAX 281.7651 there are limited areas where damage and wear have occurred. Some of the 009T -041 NOV 01 '93 04:21PM SEATTLE WA John Roddy October 29, 1993 Page 2 P.7,7 computer rooms have had the vinyl floor tiles removed and the mastic is exposed. The environmental • baseline assessment report prepared by A.D. Little, Inc. mentioned a photo laboratory and a medical laboratory.' Mr. Laskow knew nothing of these laboratories, nor was any evidence of them found during the inspection. • The only hazardous chemicals used on the site appear to have been propylene glycol, algicides, and other descalers. These materials were used in the cooling and heating system. A partly filled drum of propylene glycol and containers 'of algicides were found in the hazardous chemical storage container behind the building. The container was clean inside and there. were no unusual odors or evidence of spills. Appropriate manifest documentation (Resource, Conservation and Recovery Act [RCRA] generator manifests) appeared to be in order. There was a small sealed cardboard box with a shipping label identifying MEK as the contents. It is not certain if MEK refers to methyl ethyl ketone or some other product. The box was about 5 inches square. It is not known what the MEK was used for. Mr. Harrison met with George Naslas at the property on October 22 and discussed site conditions briefly. No other observations were made. If you have any questions, please call me. I hope that you will look to us again in the future to assist in site assessment or design needs. Sincerely, He rera Environmental Consultants, Inc. ' 'Peter Jowise, Director Hazardous Waste Services PJ:rtb 009T-041 • APPENDIX C BORING LOGS SOIL SAMPLING SERVICE, INC. IATE 10 -- ? - 3 LOG OF BORING NO E Ri ^.LIENT 6Uiro v&fru S5 OCATION 5- 17 1/4 L) 0 1/4 CITY To k ( 4_1,4 . STATE )RILLING METHOD L. / r/ 7 J . IIG # 2 1 TRlUCK # WELL ID # es. Z ` 1 START CARD # CI CI Z k./ Q CLIENT JOB # 4 3 17 t S S S JOB # 14i - "KC '•. SEC. 0 4 TOWNSHIP ? ' N RANGE (-) N .6)4 SL, COUNTY K l 1-1 DATUM /WATER ELEVATION OTHER c-�■c:l.n e ✓ DATE INSTALLED TIME & CHARGE DISTRIBUTION TOTAL TIME DRILUNG ICREWED STANDBY I NON-CREWED STANDBY MOVING INSTALLATION WATER I CLEAN +PATCH REORI L 4.430(14 514,1? 15 I-1 14,t r /rr's44 AHD Dru444<' ITRAVEL DRILLER �e Y /� HELPER Rir k eit J HELPER DRILLER'S SIGNATURE The BY JIZ \It Lnj3e HOURS Y.prewa Moro R. intg PVC BLANK TOTAL FOOTAGE SCALE 1'. FEET PAGE I OF 3 1 -- 'X S 1 E srh o PVC SCREEN /...4112.s-/1.0.0 2 .1(1 O MONUMENTTYPE 6- - /n - ?n s i1AtL� 1 1 - •I..e_ r •v a e MOBDEMOB ISAMPLE METHOD DRIVE SAMPLES ATTEMPTS EZ c'i 7 "117'"e.L ANNULUS MATERIAL OSTERBURG (..,o6 7Ob -730 • '730 -$30 1.3o- COMMENTS n A -aa� StiA. RdCheme J AT lo:3( b itisillisk SI r (4,. ti r 1« S•■••4«1.)t.# 1 /Ob -,13n c 1134 -1 tt1 ' t� o-, c_ ' i7�r w►�� s 11US''Ihlo .,cenyrvrti I 29" AS BUILT FORMATION DESCRIPTION (4V /iStS O'- sa- Gt 13-2•1 *5.1. 5,7,`t Gldt.417, .. SOIL SAMPLING SERVICE, INC. DATE /0`22-u3 LOG OF BORING NO 1'G' -1,3.. WELL ID # Pr Z g - Plc? START CARD # CO ZU 0 CLIENT . hU lI 13 OS 1 ICI €5 S CLIENT JOB # 4 3 I 1 S� S S S JOB It LOCATION i E 1/4 IV 1/4 SEC. C) LI TOWNSHIP z 9 'N RANGE Cl e4 'r CITY 1 C1 lui 1 At. , STATE L✓./9 COUNTY t-,.,7 DRILLING METHOD / IYJ1 DATUM WATER ELEVATION )41'.."0-1 2' v." r- DATE INSTALLED RIG # 7 5 TRUCK* 73' OTHER TIME & CHARGE DISTRIBUTION TOTAL TIME / DRILLER (fiver 1 t,r HOURS 2 • Z TOTAL FOOTAGE DRIWNG • f.A' HELPER Rt CIA hr CA . Z 1..,z5" CREWED STANDBY HELPER SCALE t -. FEET NON-CREWED STANDBY MOVING DRI ER'S SIGNATURE % _ '� INSTN. ATION 1 The a Wean , ate• �, BY PAGE Z OF WATER CLEAN ♦PATCH t a C� R•o► ««..r,�. • REDflLL PVC BLANK =A I - e 'X s- i 5 c h y t ANNULUS MATERIAL. AS BUILT - FORMATION DESCRIPTION Maw D,t..14 • ?S°.• PVC SCREEN / - Z ",00 n /6 Sr h'l U / � ~ ,..114O -3 3 - ��• he .Ot ! e s i ! CC ilk - sc...-Lid - - MONUMENT TYPE Jl,J�i ,..),.....„0 Z" 5 'it iv /� ;.�N,r, , /u s 5 j e �e,�.e. 1.� TRAVEL - 1 s 2" r c MOB-0EMO0 - - . M - - - - - " C: r'_ O ' z " `_ z s.�c 1 SAMPLE METHOD - ATTEMPTS / _ 1-- S v, I D r r 4 t- 4 DRIVE SAMPLES 3 OSTERBURG COMMENTS . i /G S� ��o� ABj�- IZ9 � Is .. e ' 'r 15 _..-_ r t'23n -r 30 � ��= ! o 1S %3 "j30 -.zoo ,- I.•c...4 44F. .- !-, _r 1F20 -L15+ WI _frieze tirUi.s.t . • SOIL SAMPLING SERVICE, INC. )ATE /D -7? -93 LOG OF BORING NO. E G —$ 3 WELL ID # k CZ • 13 D START CARD # ClQ .Q G CLIENT 4vir?) R U E k2 ; CLIENT JOB* 4 31.76 S.S.S. JOB* w • 110 LOCATION 5 G 1/4 PJ G_ 1/4 SEC. q TOWNSHIP Z 9 NJ RANGE L1 Pr CITY 77, PC41 1 �i STATE LA,/ A SA COUNTY k I t, C, DRILLING METHOD Li " h 5/q DATUM WATER ELEVATION RIG # 2 1 TRUCK # -J OTHER S 4061-444t V DATE INSTALLED TIME & CHARGE DISTRIBUTION ORIWNG CREWED STANDBY NON.CREWED STANDBY MOVING INSTALLATION WATER CLEAN *PATCH REDRLL TOTAL TIME 1 DRILLER+, may' HELPER e1e l&. cJ HELPER BY ER'S SIGNATURE *Orman wIthmf PVC BLANK HOURS 3.1 Imposts aCant Rpn..n*dv. L r lo ft. Sep y 0 SCALE r. FEET PAGE v OF 3 r7l�Kh r �ta of 2 " TE C ANNULUS. MATERIAL. AS BUILT P/HC. o ? /4( 1 `gas /° /0 Se-re_en TRAVEL MOB DEMOB SAMPLE METHOD DRIVE SAMPLES OSTERBURG I- z" L. Z SJ2 k �- ck /f - ,11C ATTEMPTS 1 — Sn t t c COMMENTS Z rS -31 S • I I 1 +0 2 I ,S t4 CI 1- 130 ci s�•.•. t S a- 31c Lii n S4 d! -+0 1o' •I-11C-- &ILIS r- e. (�1 L-14 5.- S d b laliftliftre.ar S rt r-u c k_ Soo -5" ^,0 2LOhn 'C0 FORMATION DESCRIPTION I ever eIc,...� c4-2 h srl t- - S=.J.S` Goss. �t Sul- GI • rctetralt$voliev 0 - NY.•t.v..- SOIL SAMPLING SERVICE, INC. )ATE 3 y 3 LOG OF BORING NO. li ` M CLIENT norm tc uSlrL2Ss _OCATION b 1/4 1/4. CITY II L) P U J I ri STATE DRILLING METHOD " RIG it Z `L TRUCK # 3 WELL ID #_..LQ� g_ 1 3i START CARD # () /)Zq CLIENT JOB # 4 /') S.S.S. JOB # W - 3 3c Z_ SEC. L! TOWNSHIP Z (I k) RANGE U h L4.2A S COUNTY et t7 DATUM WATER ELEVATION OTHER ,- 4-• L°' DATE INSTALLED TIME & CHARGE DISTRIBUTION TOTAL TIME DRIWNG ,7s CREWED STANDBY NON•CREWED STANDBY IACNING INSTALLATION WATER I,S .2S CLEAN. PATCH DRILLER �'OO rli� oj•e + t HELPER r v��Yry L•OpCZ HELPER DRILL S SIGNATURE The eon wee BY pie HOURS Represefealre TOTAL FOOTAGE SCALE I "a FEET PAGE ; OF REDRILL T l(. f Moo n-pltric,, 40,4uv -t' Ti xi:, PVC BLANK / -Z' x' - Set 1 U U PVC SCREEN ANNULUS MATERIAL MONUMENT TYPE 7 f _ Pe, iH tea Z -cl c I►os TRAVEL 1 - 2 '( E? Sew MOO DEMOB SAMPLE METHOD ATTEMPTS - 7 7r rj-C. S a � ( D r c-wt 1 - c ch, c 1-t DRIVE SAMPLES OSTERBURG '4— S/oZ c SarS (,a Lis— '? 1C COMMENTS 1lt Lt..J' 7„ct ( T ►rsp.P (1l 10 1 •Y � ' c — 7t/S'' JP/Out - as"- is 30 Dv 1,11 t`X -- 4 30 -/vvo 1�� Io ! +.0 1q.S Joao - /oso c. L'.44 -Peg* £ r (13v /bbS Seco,-•e r.x 4 /D L - 1 /OD riayt ►7ru.4.� IQt2 [) b • AS BLILT FORMATION DESCRIPTION tank APPENDIX D ANALYTICAL RESULTS Page 1 Received: 10/26/93 TOXIKON REPORT €NVIRO BUSINESS INC. TO 701 CONCORD STREET CAMBRIDGE. MA 02138 (617)868 -4321 FAX:3132 ATTEN GEORGE NASLAS CLIENT ENVIRO BUS3 SAMPLES 1¢ COMPANY ENVIRO BUSINESS INC. FACILITY 701 CONCORD STREET CAMBRIDGE. MA 02138 WORK ID LWR- PARTNERS- TUKUILA TAKEN 10/22/93. 12/23/93.& 10/25/93 TRANS TYPE WATER AND SOIL P.O. 0 INV. N 006463 CORP. REPORT York Order t 93- 10-386 11/10/93 17:34:23 York Not Couplet* PREPARED TOXIKON CORPORATION BY 225 WILDWOOD AVE WOBURN. MA 01801 ATTEN PAUL LEZBERG PHONE (617)933 -6903 • CERTIF D BY. CONTACT KAR MA CERT N MA064: TRACE METALS, SULFATE.CYANIDE.RES. FREE CHLORINE, Ca. TOTAL ALK.. TDS. pH. THMs, VOC, PEST..NUTRIENTS. DEMAND. 08G. PHENOLICS. PCBs CT DHS NPH -0563. NY 010778 FL HRS E87143. NJ DEP ,59538. NR286, ,SC 88002. NH 204091 -C. VERIFIED BY: 't1 MASS DEP - CERT 0MA064 Previously Reported on 10/29/93. SAMPLE IDENTIFICATION 01 E8 -1 Oj EB -2 03 EB -3 04 18 -4 05 E8 -4 06 E8 -4 07 E8 -2 08 E8 -2 OS EB -1 10 E8 -1 11 EB -3 1a EB -3 13 EB-1 14 EB -2 15 EB -3 16 E8 -4 TEST CODES and NAMES used on this vorkorder 624 PURGEABLE ORGANICS VOA MEX HG METALS. EXT. FOR MERCURY MEX TW METALS. TOTAL EXT.. WATER pP13 METALS.13 PRI.POLL. TPH IR TPH BY IR Page 2 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample York Order N 93- 10-386 SAMPLE ID Eli-1 SAMPLE Si 001 FRACTIONS: A Date & Time Collected 10/25/93 12:30:00 Category RATER TPH IR ND mg /L DL =1.0 SAMPLE ID ED-2 SAMPLE M 02 FRACTIONS: A TPH IR ND mg /L DL=1.0 Date & Time Collected 10/25/93 11:30:00 Category RATER SAMPLE ID E8-3 SAMPLE M 03 FRACTIONS: A TPH IR NO mg /L DL =1.0 Date & Time Collected 10/25/93 13:00 :00 Category WATER SAMPLE ID E5-4 SAMPLE M Oi FRACTIONS: A TPH IR ND mg /L DL =1.0 Date & Time Collected 10/25/93 10:30:00 Category WATER Page 3 Received: 10/26/93 SAMPLE ID E8-4 TOXIIODN CORP. REPORT Results by Sample York Order N 93- 10-386 FRACTION 214. TEST CODE PP13 NAME RETALS.13 PRI.POLL. Date & Time Collected 10/25/93 10:30 :00 Category WATER 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver ND 0.020 Cadmium ND 0.010 Chromium ND 0.010 Copper 0.010 0.010 Nickel ND 0.040 Lead ND. 0.005 Zinc 0.025 0.0060 Arsenic ND 0.005 Selenium ND 0.005 Beryllium ND 0.0040 Antimony 0.009 0.005 Thallium ND 0.005 Mercury 0.001 0.0005 Notes and Definitions for this Report: EXTRACTED 10/26/93 DATE RUN 10/27/93 ANALYST SN INSTRUMENT ICP DIL. FACTOR 1 UNITS ma /4 ND = Not detected at detection limit Page 4 Received: 10/26/93 SAMPLE ID E5-4 TOXIIODN CORP. REPORT Results by Sample York Order • 93- 10-356 FRACTION OA TEST CODE 624 NAME PURGEABLE ORGANICS VOA Date & Time Collected 10/25/93 10:30:00 Category PATER PURGEABLE QRGANICS VOA RESULT LIMIT Chloromethane Bromomethane Vinyl Chloride Chloroethane Methylene Chloride Acetone Carbon Disulfide 1,1- Dichloroethene 1,1- Dichloroethene Trans -1,2- Dichloroethene Chloroform 1,2- Dichloroethene 2- Butanone 1,1,1 - Trichloroethane Carbon Tetrachloride Vinyl Acetate Bromodichloromethane 1,2- 01chloropropane trans -1,3- Dichloropropene ND 2.0 NO 2.0 NO _ 0 ND 2.0 ND 10 ND 50 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 10 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 Trichloroethene Dibromochloromethane 1,1,2 - Trichloroethane Benzene cis -1,3- Dichloropropene 2- Chloroethylvinylether Bromoform 2- Hexanone 4- Methyl -2- pentanone Tetrachloroethene 1,1,2,2- Tetrachtoroethane Toluene Chlorobenzene Ethyl Benzene Styrene Total Xylenes Trichloroftuoromethene 1,2- Dichlorobenzene 1,3- Dichlorobenzene 1,4- Dichlorobenzene Notes and Definitions for this Report: DATE RUN 10/27/93, ANALYST DPV INSTRUMENT HP -1 DIL. FACTOR 1.0 UNITS = ug /L ND = not detected at detection limit RESULT LIMIT ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 NO 4.0 ND 4.0 ND 2.0, ND 2.0 NO 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 NO 2.0, ND 2.0 ND 2.0, ND 2.0 Page 5 Received: 10/26/93 SAMPLE ID E8-2 TOXIIOON CORP. REPORT Results by Sample York Order N 93- 10-386 FRACTION 07A TEST CODE PP13 NAME METALS -13 PRI.POLL. Date 8 Time Collected 10/25/93 11:30:00 Category PATER 13 PRIORITY POLLUTANT METALS • RESULT LIMIT Silver ND 0.020 Cadmium ND 0.010 Chromium ND 0.010 Copper ND 0.010 Nickel ND 0.040 Lead ND 0.005 Zinc 0.010 0.0060 Arsenic ND 0.005 Selenium ND 0.005 Beryllium ND 0.0040 Antimony ND 0.005 Thallium ND 0.005 Mercury ND 0.0005 • Notes and Definitions for this Report: EXTRACTED 10/26/93, DATE RUN 10/27/93 ANALYST SN INSTRUMENT ICP DIL. FACTOR 1 UNITS mo /I, ND = Not detected at detection limit Page 6 Received: 10/26/93 SAMPLE ID EB-2 TOXIKON CORP. REPORT Results by Sample York Order 8 93- 10-386 FRACTION gm TEST CODE 624 NAME PURGEABLE ORGANICS VOA Date & Time Collected 10/25/93 11:30:00 Category YATE PURGEABLE ORGANICS VOA RESULT Chtoromethane Eromomethane Vinyl Chloride Chloroethane Methylene Chloride Acetone Carbon Disulfide 1,1- Dichloroethene 1,1- Dichtoroethane Trans- 1,2- Dichloroethene Chloroform 1,2- 01chloroethane 2- Butanone 1,1,1 - Trichloroethene Carbon Tetrachloride Vinyl Acetate Bromodichloromethane 1,2- Dichtoropropane trans -1,3- Dichloropropene LIMIT NO 2.0 ND 2.0 NO 10 ND 2.0 NO 10 NO 50 NO 2.0 ND 2.0 NO 2.0 ND 2.0 NO 2.0 ND 2.0 ND 10 ND 2.0 ND 2.0 ND 2.0 ND 2.0 NO 2.0 ND 2.0 Trichloroethene 0i bromochloromethane 1,1,2- Trichloroethane Benzene cis -1,3- Dichloropropene 2- Chloroethylvinytether Bromoform 2- Hexanone 4- Methyl- 2- pentanone Tetrachloroethene 1,1,2,2- Tetraehloroethane Toluene Chlarobenzene Ethyl Benzene Styrene Total Xylenes Trichlorofluoromethane 1,2- 0ichlorobenzene 1,3- Dichlorobenzene 1,4- Dichlorobenzene Notes and Definitions for this Report: DATE RUN 10/27/93 ANALYST DPV INSTRUMENT HP -1 DIL. FACTOR 1.0 UNITS = ug /L ND = not detected at detection limit RESULT LIMIT ND 2.0 ND 2.0 N0 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 4.0 ND 4.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND '2.0 Page 7 Received: 10/26/93 SAMPLE ID EB-1 TOXIKON CORP. REPORT Results by Sample York Order 0 93- 10-386 FRACTION 09A TEST CODE PP13 NAME NETALS.13 PRI.POLL. Date 6 Time Collected 10/25/93 12:30:00 Category WATER 13 PRIORITY POLLUTANT METALS RESULT •LIMIT Silver ND 0.020 Cadmium ND 0.010 Chromium _ND 0.010 Copper ND 0.010 Nickel ND 0.040 Lead 0.010 0.005 Zinc NO 0.0060 Arsenic ND 0.005 Selenium NO 0.005 Beryllium NO 0.0040 Antimony ND 0.005 Thallium NO 0.005 Mercury 0.001 0.0005, Notes and Definitions for this Report: EXTRACTED 10/26/93, DATE RUN 10/27/93 ANALYST SN INSTRUMENT ICP DIL. FACTOR 1, UNITS mo /l, ND = Not detected at detection limit • Page 8 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample SAMPLE ID EB-1 Work Order X 93-10 -386 FRACTION 10A TEST CODE 624 NAME PURGEABLE ORGANICS VOA Date i Time Collected 10/25/93 12:30:00 Category WATER PURGEABLE ORGANICS VOA RESULT Chloromethane Bromomethane Vinyl Chloride Chloroethane Methylene Chloride Acetone Carbon Disulfide 1,1- Dichloroethene 1,1- Dichloroethane Trans- 1,2- Dichloroethene Chloroform 1,2- Dichloroethane 2- Butanone 1,1,1- Trichloroethane Carbon Tetrachloride Vinyl Acetate Bromodichloromethane 1,2- Dichloropropene trans -1,3- Dichloropropene LIMIT ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND RESULT LIMIT 2.0 Trichloroethene ND 2.0 z.0 Dibromochloromethane ND - 2.0 10 1,1,2 - Trichloroethane ND - 2.0 2.0 Benzene NO 2.0 10 cis -1,3- Dichloropropene ND - 2.0 50 2- Chloroethylvinylether ND 2.0 2.0 Bromofora ND 2.0 2.0 2- Hexanone ND 4.0 2.0 4- Methyl -2- pentanone ND' 4.0 2.0 Tetrachloroethene ND 2.0 2.0 1,1,2,2- Tetrachloroethane ND 2.0 2.0 Toluene ND 2.0 10 Chlorobenzene ND 2.0 2.0 Ethyl Benzene ND 2.0 2.0 Styrene ND 2.0 2.0 Total Xylenes ND 2.0 2.0. Trichlorofluoromethane ND 2.0 2.0 1,2- Dichlorobenzene NO 2.0 2.0 1,3- Dichlorobenzene ND 2.0 1,4- Dichlorobenzene . ND •2.0 Notes and Definitions for this Report: DATE RUN 10/27/93 ANALYST DPV. INSTRUMENT HP -1 DIL. FACTOR 1.0 UNITS = ug /L ND = not detected at detection limit Page 9 Received: 10/26/93 SAMPLE ID E8-3 TOXIKON CORP. REPORT Results by Sample Work'Order 0 93- 10-386 FRACTION 1j TEST CODE PP13 NAME METALS,13 PRI,POLL. Date & Time Collected 10/25/93 13:00 :00 Category WATER 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver ND 0.020 Cadmium ND 0.010 Chromium ND 0.010 Copper 0.013 0.010 Nickel ND 0.040 Lead ND 0.005 Zinc ' ND 0.0060 Arsenic ND 0.005 Selenium ND 0.005 Beryllium ND 0.0040 Antimony ND 0.005 Thallium ND 0.005 Mercury 0.001 0.0005 Notes and Definitions for this Report: EXTRACTED 10/26/93, DATE RUN 10/27/93 ANALYST SN INSTRUMENT 1CP DIL. FACTOR 1 UNITS ma /L, ND = Not detected at detection limit Page 10 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample SAMPLE 10 EB-3 York Order N 93- 10-386 FRACTION 14 TEST CODE 624 NAME PURGEABLE ORGANICS VOA Date & Time Collected 10/25/93 13 :00:00 Category WATER PURGEASLE ORGANICS VOA RESULT LIMIT Chloromethane Bromomethane Vinyl Chloride Chloroethane Methylene Chloride Acetone Carbon Disulfide 1,1- Dichloroethene 1,1= Dichloroethane Trans -1,2- Dichloroethene Chloroform 1,2- Dichloroethane 2- Butanone 1,1,1- Trichloroethane Carbon Tetrachloride Vinyl Acetate Bromodichloromethane 1,2- Dichloropropane trans- 1,3- Dichloropropene ND 2.0 Trichloroethene ND 2.0 Dibromochloroaethane NO 10 1,1,2-Trichloroethane ND 2.0 Benzene ND 10 cis- 1,3- Dichloropropene ND 50 2- Chloroethylvinylether ND 2.0 Bromofora ND 2.0 2-Hexanone NO 2.0 4- Methyl -2- pentanone ND 2.0 Tetrachloroethene ND 2.0 1,1,2,2- Tetrachloroethane ND 2.0 Toluene ND 10 Chlorobenzene ND 2.0 .Ethyl Benzene ND 2.0 Styrene ND 2.0 Total Xylenes ND 2.0 Trichlorofluoromethane ND 2.0 1,2- Dichlorobenzene ND 2.0 1,3- Dichlorobenzene 1,4- Dichlorobenzene Notes and Definitions for this Report: DATE RUN 10/27/93 ANALYST DPV INSTRUMENT HP -1 OIL. FACTOR 1.0 UNITS = ug /L ND = not detected at detection limit RESULT LIMIT ND 2.0 ND 2.0 ND 2.0 ND 2.0. ND 2.0 ND 2.0 ND 2.0 ND 4.0 ND 4.0 ND 2.0 ND 2.0, ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 ND 2.0 NO 2.0 ND 2.0 s Page 11 TOXIIOON CORP. REPORT Received: 10/26/93 Results by Sample York Order 8 93- 10-386 SAMPLE ID ES-1 SAMPLE M 13 FRACTIONS: A Date & Time Collected 10/22/93 11:00 :00 Category SOIL TPH IR ND mg /Kg 0L =40 • Page 12 Received: 10/26/93 SAMPLE ID EB-1 TOXIKON CORP. REPORT Results by Sample York Order N 93- 10-386 FRACTION 131 TEST CODE PP13 NAME METALS.13 PRI.POLL. Data i Time Collected 10/22/93 11:00 :00 Category SOI 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver ND 1.3 Cadmium 2.79 0.66 • Chromium 37.8 0.66 Copper 26.6 0.66 Nickel 39.1 2.6 Lead 5.00 1.00 Zinc 40.0 0.39 Arsenic 6.30 1.50 Selenium 3.22 0.500 Beryllium ND 0.26 Antimony ND 0.500 Thallium ND 0.500 Mercury ND 0.324 Notes and Definitions for this Report: EXTRACTED 10/28/93 DATE RUN 10/28/93 ANALYST BK0 INSTRUMENT ICP DIL. FACTOR 1 UNITS mo /Kq ND = Not detected at detection limit . Pape 13 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample York Order N 93- 10-386 SAMPLE ID EB-2 SAMPLE N L FRACTIONS: A Date i Time Collected 10/22/93 14:00 :00 Category SOI TPH IR ND mg /Kg DL =40 Page 14 Received: 10/26/93 SAMPLE ID EB-2 TOXIKON CORP. REPORT Results by Sample York Order N 93- 10-386 FRACTION 14A TEST CODE PP13 NAME METALS.13 PRI.POLL. Date & Time Collected 10/22/93 14:00:00 Category SOI 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver ND 1.3 Cadmium 2.11 0.66 Chromium 33.6 0.66 Copper 18.0 0.66 Nickel 37.9 2.6 Lead 2.75 0.500 Zinc Arsenic Selenium Beryllium Antimony Thallium Mercury 38.6 0.39 4.22 1.50 4.41 0.500 ND 0.26 ND 0.500 ND 0.500 ND 0.324 Notes and Definitions for this Report: EXTRACTED 10/28/93 DATE RUN 10/28/93 ANALYST BKO INSTRUMENT ICP DIL. FACTOR 1 UNITS me /KQ ND = Not detected at detection limit Page 15 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample York Order / 93- 10-386 SAMPLE ID EB-3 SAMPLE N 11 FRACTIONS: A Date & Time Collected 10/22/93 16 :00 :00 Category SOI TPN IR ND mg /Kg DL =40 Page 16 TOXIKON CORP. REPORT Received: 10/26/93 Results by Sample York Order / 93- 10-386 SAMPLE ID EB-3 FRACTION 15A TEST CODE PP13 NAME METALS.13 PRI.POLL. Date 6 Time Collected 10/22/93 16:00:00 Category SOIL 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver ND 1.3 Cadmium 2.42 0.66 Chromium 37.1 0.66 Copper 18.2 0.66 Nickel 43.2 2.6 Lead 2.85 0.500 Zinc 40.6 0.39 Arsenic 3.75 1.50 Selenium 3.41 0.500 Beryllium ND 0.26 Antimony ND 0.500 Thallium ND 0.500 Mercury ND 0.324 Notes and Definitions for this Report: EXTRACTED 10/28/93, DATE RUN 10/28/93 ANALYST BKO INSTRUMENT ICP DIL. FACTOR 1 UNITS mo /Kq NO = Not detected at detection limit s Page 17 TOXIKON CORP. REPORT Received: 10/26/93 Results by Semple York Order • 93- 10-306 SAMPLE ID ER-4 TPH IR ND mg /Kg DL =40 SAMPLE N 16 FRACTIONS: A Date $ Time Collected 10/23/93 10:00:00 Category SO • Pape 18 Received: 10/26/93 SAMPLE ID E9-4 TOXIKON CORP. REPORT Work Order N 93- 10-386 Results by Sample FRACTION 16A TEST CODE PP13 NAME METALS.13 PRI.POLL. Date & Time Collected 10/23/93 10:00:00 Category SOIL 13 PRIORITY POLLUTANT METALS RESULT LIMIT Silver NO 1.3 Cadmium 8.33 0.66 Chromium 68.9 0.66 Copper 37.8 0.66 Nickel 70.0 2.6 Lead 4.98 1.00 Zinc 102 0.39 Arsenic 5.39 1.00 Selenium 2.96 0.500 Beryllium 1.10 0.26 Antimony ND 0.500 Thallium ND 0.500 Mercury ND 0.324 Notes and Definitions for this Report: EXTRACTED 10/28/93, DATE RUN 10/28/93 ANALYST BKO INSTRUMENT ICP DIL. FACTOR 1 UNITS ma /Kq ND = Not detected at detection limit Page 19 TOXIKON'CORP. REPORT Received: 10/26/93 Test Methodology TEST CODE 624 , NAME PURGFARJF ORGANICS VOA EPA METHOD: 624 Reference: Methods for Organic Chemical Analysis of Municipal and Industrial Wastewater. Appendix A. 40CFR Part 136. Federal Register Vol. 49, No. 209, 1984. TEST CODE MEX HG NAME METALS, EXT. FOR MERCURY York Order R 93- 10-386 REFERENCE: EPA METHOD 245.1 Mercury. Methods for Chemical Analysis of Water and Wastes. EPA 600/4 -79 -020. TEST CODE MEX TV NAME METALS, TOTAL EXT.. WATER REFERENCE: EPA METHOD 3005. Acid Digestion of Waters for Total Recoverable or Dissolved Metals for Analysis by Flame Atomic Absorption Spectroscopy or Inductively Coupled Plasma Spectroscopy. Test Methods for Evaluating Physical /Chemical Methods. SW 846, 3rd Edition. Wastewater digestion 40CFR Part 136 Appendix C- Preparation for Inductively Coupled Plasma - Atomic Emission Spectrometric Method for Trace Element Analysis'of Water and Wastes Method 200.7. Protection of Environment, 1991. TEST CODE TPH IR NAME TPH BY IR EPA METHOD: 418.1 for water sample. Reference: Methods for Chemical Analysis of Water and Wastes. EPA 600/4-79-020 (Revised, March 1983). EPA /EMSL, Cincinnati, OH. EPA METHOD: 9073 for soil sample. Reference: Test Methods for Evaluating Solid Waste: Physical /Chemical Methods. EPA SW-846 (Third Edition) 1986. Office of Solid Waste, USEPA. APPENDIX E HNu PHOTOIONIZATION DETECTOR SPECIFICATIONS AND SCREENING PROCEDURES HNu Photoionization Detector Field screening for the presence of volatile organic compounds (VOCs) was carried out using a photoionization detector (PID) equipped with an eleven and seven- tenths (11.7) eV bulb. The PID draws the gases of interest into an ionization chamber where the sample is exposed to ultraviolet light. The light is of sufficient energy to ionize many trace gas species such as VOCs, but not the major components of air. Ionization renders the trace gases detectable .to electrodes located in. the ionization chamber. Their concentration is displayed on the instrument meter in parts per million (ppm). Before field screening the PID was calibrated using a certified iso -C4HS (iso-butylene) standard provided by Hazco. PID Field Screening Techniques The following methods were employed while screening soils for the presence of volatile organic compounds (VOCs) with the PID: Headspace Screening Technique Several 200 milliliter samples were collected at regular intervals and placed into a 250 milliliter glass jar, which was then covered with foil before capping. The sample was shaken for a period of thirty (30) seconds and placed in a warm area for approximately ten (10) minutes in order to facilitate the volatilization of any VOCs trapped in the sample. Each cap was then removed and the end of the PID probe intake was poked through the foil and the air in the jar above the sample (the headspace) was analyzed for the presence of VOCs. Ambient Air Screening Technique The PID probe intake was held approximately 2 -3 inches above soil driven up to the ground's surface by the rotation of a borehole drill and the air above the soil was sampled. Soil -Gas Survey Technique VOCs in groundwater and/or subsurface soils can be detected by analyzing_the uses in the surrounding soil matrix since many VOCs will volatilize from the contamination source and move by molecular diffusion from source areas towards regions of lower concentration in surrounding soils. Well Headspace Technique VOCs degassing from groundwater or migrating through soil pore spaces, build up in the well headspace. This is the area above the water surface enclosed within the well bore. Immediately upon removal of the expansion plug capping the monitoring well, the PID intake probe was placed down the well. After approximately thirty seconds, the maximum reading recorded by the PID was recorded Soil- Screening PID readings from soil screening ranged from 0.8 to 1.0E ppm. These are within background levels. APPENDIX F MONITORING WELL REQUIREMENTS • YOUR WELL I.D. NUMBER X Y Z 1 2 3 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Mail Stop PV-11 • Olympia, Washington 98504 -8711 • (206) 4594000 Dear Well Owner. The State of Washington has started a Well Identification Program to protect Washington's ground water. This Program will help protect your well, your health, and your property values. Building a record of good well and water quality protection is money in the bank. Your well has been assigned a well identification number. It is printed on the metal tag which is attached to your well. This unique well number should remain affixed to your well forever and should be written on all information about your well and referenced in all inquiries about your well. Your well identification number will assist you in tracking water quality and water quantity changes in your well. It also establishes a link between well construction and public health records. In addition to using your well identification number, we recommend the following protection practices for your well to preserve. the quality of your drinking water: ✓ Test your well for bacteria annually and for nitrates every three years (especially if you have an infant under six months of age). Additionally, you may want to test for chloride (an indicator of seawater intrusion) if your well is located near the coast. Be sure to write your well identification number on each lab slip. ✓ Keep your well tightly capped with a sanitary seal to keep surface contaminants and small animals or insects out. Maintain screening on any vents or openings on top of your well casing. ✓ Keep the area around your well clean. DON'T: Q1 Remove the well identification tag. �d Store hazardous materials such as paint, oil, gasoline, anti - freeze, garden chemicals, rat poison, and trash near your well or in your well house. 0 Let farm animals pasture around your well, particularly if the well is in a low spot where water can collect. If you have any questions about testing your well, please contact your local Health Department. If you have questions about the Well Identification Program, call Maryrose Livingston at the Department of Ecology Water Resources Program at (206) 493 -9226. We all have a stake in clean ground water - with your help we can protect our : •und water for your use and for future generations. Si Adelsman, Program Manager ment of Ecology Water Resources Program molgiois 0 APPENDIX G GROUNDWATER FLOW CALCULATIONS Groundwater Flow Calculations 1. Purpose To determine the direction of groundwater flow and hydraulic head gradient. 2. Procedures 1) The depth to groundwater was determined following the procedures outlined in Appendix G. 2) The well casings were surveyed in and referenced to an arbitrary datum of 100 feet. Survey Information Location Angle High Med. Low EB -1 2240 5.06 4.49 3.93 EB -3 128° 7.00 6.38 5.76 Ref. Pt. 171° 1.99 1.74 1.48 EB -3 backsight 313° 5.54 5.00 4.46 EB-4 183° 6.22 5.74 5.26 EB -2 186° 7.49 6.17 4.82 nig: Sightings to EB -2, EB-4 and the backsight to EB -3 were from the second transit position. 3) From this information well casing and groundwater surface elevations were calculated Well Groundwater Well Casing surface Elevations Elevations EB -1 97.25 86.66 EB -2 94.19 89.92 EB -3 95.36 83.76 EB-4 94.62 83.90 Note: Referenced to a 100' datum 4) Groundwater flow was calculated following the procedure outlined in Groundwater and Wells, pp 80-82. Groundwater was calculated in the area of wells EB -2, EB -3 and EB-4, to be flowing to the east- northeast on a bearing of 0.660 referenced to magnetic north. The hydraulic head gradient was calculated at 0.0657, equivalent to a one foot head drop per 15.2 feet. 3. References: Johnson Filtration Systems, "Groundwater and Wells" pp. 80-82. APPENDIX H SAMPLING PROCEDURES Sample Collection - Monitoring Wells 1. Purpose: To obtain liquid samples for analysis to determine general quality of the groundwater at the sampling location or as part of a program to define a contaminant plume. 2. Equipment and Materials • Appropriate sample containers • Designated disposable bailers • Sampling cable • 100 -foot electronic measuring tape with weighted end • Rags or paper towels • Cooler and ice Additional equipment and materials included the field screening equipment (OVM Photoionization Detector). 3. Procedures A. Prior to sample collection, three times the volume of standing water in the well was removed using the following method 1) Measured depth to groundwater to the nearest 0.01 -foot from the top of the riser pipe using the 100 -foot electric water level indicator. 2) Measured total well depth to the nearest 0.1 foot from the top of the riser pipe using the 100 -foot electric water level indicator. Wells Bottom WW Depth Column # Bailers purged EB -1 18.88' 10.59' 8.29' 7.5 (& 3 galls.) , EB -2 15.47' 4.27' 11.20' 20 (& 3 galls.) EB -3 19.34' 11.60' 8.74' . 20 EB -4 19.62' 10.72' 8.90' 20 (& 10 galls.) 3) Calculated the volume of standing water in the well using the above measurements and the inside diameter of the well. 4) Using the disposable bailer of known volume, three times the volume of water calculated in (3) was bailed from the well. 5) Allowed sufficient time for well to recharge before initiating sampling. B. Using a designated disposable bailer, a sample was withdrawn from the well. C. The sample was transferred from the bailer directly into the sample container by pouring the liquid down the side of the container with minimum turbulence. This procedure is critical to minimize loss of volatile materials from the sample through aeration. D. Sample containers were capped and sealed, labeled, preserved, and stored in accordance with appropriate protocols. 4. Records and Documentation All data and sampling information was recorded in a separate fieldbook and information was transposed into this Investigation. 5. Special Notes Separate disposable bailers were used for each well sampled to preclude cross - contamination. Separate bailer cables were also employed. 6. Applicable References and Standards Dunlap, N.J.; McNabb, J.F.; Scalf, M.R.; and Crosby, R.L., "Sampling for Organic Chemicals and Microorganisms in the Subsurface," EPA - 600/2- 77 -16, August 1977. STORM DRAINAGE REPORT PARK PLACE REDEVELOPMENT TUKWILA, WASHINGTON BRH PROJECT No. 94187.02 BUSH, ROED & HITCHINGS 2009 MINOR AVENUE EAST SEATTLE, WA 98102 PHONE:(206) 323 -4144 CONTACT: JOHN E. ANDERSON, P.E. March 13, 1995 RECEIVED MAR 2 21995 COMIVIUNI FY DEVELOPMENT OJY r` tt u sera , .) :.i:.. TUK.I.Aii LA PUBLIC VIPORKS CITYECVED OFT TUKWILA MAR 1 5 1995 PERMIT CENTER Park Place is a 15.54 acre site as delineated on the architect's site plan. The project is located along Southcenter Boulevard in Tukwila, Washington. Located on the site is a 9 story office building which was occupied by Boeing. The tenant has moved out of the facility and the owner is looking to find a more viable use for the property. This proposal would demolish the existing building and construct approximately 3.5 acres of retail space on the property. There are several existing utility lines and easements across the site. We have used an ALTA survey and topographic information prepared by Chadwick Surveying and Engineering, available WSDOT and City as -built records and BRH pot hole information to establish utility locations. A new section has been added to this report to discuss the existing utilities in more detail. This section has been added in response to the City of Tukwila letter dated October 31, 1994. The existing site is generally flat. A steep slope rises on the west side of the property to Interstate 5. The slope is covered with trees and thick underbrush. A railroad easement was located along the toe of slope. The railroad easement has been vacated. The 9 story building is located approximately midway between the railroad easement and Southcenter Boulevard. The existing building has a footprint of approximately 24,981 square feet., The remainder of the site is covered by asphalt parking and landscaping. Detailed surface area coverage calculations have been prepared and are shown on page 4 of this report. Two other buildings share the existing parking and access points to Southcenter Boulevard. Each of the buildings are located on segregated parcels and have not been included in the area count for the Park Place project. These structures are to be remain after the completion of the shopping center. Some grading of the parking area between the two building may be necessary for the construction of the new retail building. Final design will also require coordination of utility connections for the sewer and water main relocation. This subject will be discussed in more detail in the new section of the report. Redevelopment of this site will include the construction of two retail buildings. A 26,760 square foot building in the southwest corner and a 136,619 square foot building along the western boundary of the slope. The 136,619 square foot building will cover the area occupied by the existing 9 story office building. Some of the existing utility lines serving the site will have to be routed around the new buildings. This includes extending a water main loop around the west side of the new buildings, relocation of an existing 48 inch storm pipe and routing the existing sanitary sewer main around the east side of the buildings. The new buildings have been located so that the existing 66 and 54 inch storm drainage pipes from the southern off -site areas do not have to be relocated. Storm Drainage Report March 13, 1995 Page 2 Existing parking areas will be retained to the greatest possible extent. Some additional parking will be gained along the west side of the 136,619 square foot building with the relinquishment of the railroad easement. The new building has been located further west than the existing 9 story building. This will require construction of a retaining wall along the western margin of the site plan. Construction documents for the retaining wall have been submitted to the City for review. A soldier pile wall with a shotcrete facing will be constructed. The advantage of using this type of retaining structure is that it can be constructed with minimal disturbance to the areas above the top of wall. We have located all relocated utilities to the east side of the building. There was a great deal of concern about the influence of trenching the deeper utilities along the face of wall. Moving the utilities to the east side of the building will increase the construction cost, but it relieved the concerns pertaining to the wall design. Therefore, the only utilities located in the drive lane at the base of wall will be power, gas, water and storm drainage pipe. Trench depths for these utilities will not extend into the passive pressure zone of the wall. There is a public storm drainage system servicing the site from Southcenter Boulevard. Storm water will be collected in catch basins and conveyed using underground pipe. Much of the existing storm system in the vicinity of the existing building will be abandoned. The site has been graded so that finished grade elevations around the new buildings are higher than the existing grade. Therefore the storm water will sheet flow to the existing catch basins located in the eastern parking areas. Loading docks on the western side of the buildings are the only locations where a new storm collection system will have to be installed. The proposed site plan reduces the net parking area by approximately 1.5 acres. Since the area subject to vehicular traffic will be reduced, there should be a corresponding improvement in storm water quality discharged to the downstream system. Oil /water separator vaults with coalescing chambers and high flow bypasses will also be installed to improve water quality prior to discharge to the downstream system. The site is served by public sewer. Redevelopment of the site to a retail center will significantly reduce the sanitary sewer discharge. The 9 story office building contained approximately 214,600 square feet of floor space and supported a population of approximately 2,230 people. The proposed 162,889 square feet of retail space will reduce the sewer discharge by approximately 31,650 gpd based on the D.O.E. Table No. 2 for new system design. Therefore redevelopment of this site to a retail facility will benefit the existing sewer system. Storm Drainage Report March 13, 1995 Page 3 SURFACE AREA COVERAGE Existing site: 676,948 SF (15.54 AC) IMPERVIOUS ROOF AREA = 24,981 SF (0.57 AC). IMPERVIOUS A.C. AREA = 383,677 SF (8.81 AC) IMPERVIOUS RAIL AREA = 26,136 SF (0.6. AC) PERVIOUS LANDSCAPE = 83,666 SF. (1.92 AC) PERVIOUS WEST SLOPE = 158,488 SF (3.64 AC) Redeveloped site: 676,948 SF (15.54 AC) IMPERVIOUS ROOF AREA = 162,900 SF (3.74 AC) IMPERVIOUS A.C. AREA = 320,957 SF (7.37 AC) IMPERVIOUS RAIL AREA = 0 AC (0.0 AC) PERVIOUS LANDSCAPE = 52,826 SF (1.21 AC) PERVIOUS WEST SLOPE = 140,265 SF (3.22 AC) Storm Drainage Report March 13, 1995 Page 4 ADDITIONAL UTILITY INFORMATION Storm Drainage System: There are two major drainage courses draining beneath the Interstate 5 and conveyed through the site. The most northerly course discharges from a 48 inch culvert approximately 70 feet west of the northwest property corner. At the discharge point, a concrete energy dissipator with "V" notched weirs on the bottom side has been installed. Storm water flows east from the discharge in a 15 foot wide grass lined ditch to a 48 inch concrete culvert located approximately 20 feet east of the northwest property corner. The grass lined ditch area has been classified as a Class 4 stream. All work related to the Parkway Place project will occur outside the stream area. There is a concrete box inlet with a heavy steel trash rack at the 48 inch intake. From this point the storm water is conveyed in the 48 inch culvert approximately 145 feet to a 45 degree bend in the line. The bend directs the flow in a southeasterly direction toward a manhole located within the drive lane of the Parkway Place parking lot. An 11 foot wide concrete spillway has been constructed above the 48 inch culvert between the intake and 45 degree bend. The spillway directs the overflow to two 30 inch CMP culvert inlets located at the edge of parking, approximately 60 feet north of the northwest property line. The overflow lines convey the storm water easterly to Southcenter Boulevard and then northward in the street system. Therefore, once the inlet capacity of the 48 inch culvert is exceeded, the flow is routed to a separate storm system. Storm water flow in the 48 inch culvert is turned southward at the most northern manhole. John Howard, with the City of Tukwila, opened the manhole structure for my observation. The manhole has a round lid at the asphalt paving surface which covers a locking lid on the pipe. It is my understanding that the locking lid is required because the 48 inch pipe flows under pressure during heavier rainfall events or when the river is at a higher elevation. At the time of my observation, there was approximately 6 inches of water flowing in the pipe. Stones with a diameter of approximately one foot were also observed at the bottom of the pipe. From the manhole the 48 inch pipe conveys the storm water approximately 850 feet south. The pipe is deflected 21 degrees to the west approximately 570 feet south of the manhole. Approximately 180 feet south of the bend, the pipe is deflected 64 degrees to the east. The 48 inch pipe then extends 90 feet where it connects to a 66 inch culvert. Connection to the 66 inch pipe Storm Drainage Report March 13, 1995 Page 5 is accomplished using a wye. The 66 inch culvert then conveys the storm water easterly to Southcenter Boulevard. The second off -site drainage course discharges from an arched culvert on the east side I -5 located near the southwest property corner. The discharge flows into a fenced pool area. The pool flows into a 54 inch culvert which conveys the storm water easterly. The culvert is located just south of the southwest property line. There is an asphalt maintenance road above the culvert between the Parkway Place parking lot and the pool area. The 54 inch pipe is connected to the 66 inch culvert which also conveys the storm water from the 48 inch pipe discussed above. It does not appear that any manholes exist along the 54 inch pipe between the pool and 66 inch pipe. 48" Storm Relocation: The existing 48 inch storm pipe will have to be abandoned because the new buildings will be located over the line. The new line will be located to the east side of the new building.. We have worked closely with Associated Sand & Gravel throughout the design process on detailing the new storm system. This a unique system because of the head pressures exerted by the storm water. We have designed the manhole at the connection point and new 48 inch storm pipe to resist a force of 150 psi. Preliminary details of the connection manhole were sent to WSDOT for review. We have received WSDOT approval on the details submitted. The new pipe will be installed with a greater slope than provided by the existing system. This will increase the gravity flow capacity of the 48 inch pipe. The new line will be constructed so that access points do not exceed 400 feet. Construction documents for the existing pipe were obtained from WSDOT. Details and specifications used in the original pipe construction have been reproduced for this project. These details and specifications have been given to Associated Sand & Gravel. Telephone conversations I have had with their pipe designers indicates that the materials can be manufactured. Relocation of the 48 inch pipe will not alter the basin characteristics. The new line will remain a conveyance system for off -site flows only. No catch basin for on -site drainage will be connected to the new line. Therefore drainage from the site will not enter the pipe during or after construction. The abandoned section of 48 inch pipe will be capped at the ends. GeoEngineers has prepared recommendations on how to deal with the sections under the building slab and foundation. The abandoned Storm Drainage Report March 13, 1995 Page 6 section can remain under the building and does not require additional treatment. The pipe does not have to be filled with CDF or be crushed and backfilled. Where the pipe crosses the north and south exterior walls, the footing will be designed as a grade beam. Interior column footings which are located near the pipe will have piles extending below the invert elevation of the pipe. Therefore, the abandoned sections of pipe will not be subjected to increased building loads. Sanitary Sewer System: The sanitary sewer main enters the site from the south near the southeast property corner. In the southern driveway, the sewer main is turned west and extends approximately 675 feet to a manhole located west of the asphalt parking lot. The sewer then angles northward to the loading dock area on the west side of the existing 9 story building. The manhole for the building connection is approximately 17 feet deep. There is an electronic flap gate on the building service line to prevent sewer from flowing into the building line. From this manhole the sewer main continues northward approximately 640 feet to a manhole located in the northwest corner of the site. This manhole also collects flows from areas north of the Parkway Place site. From the manhole in the northwest corner of the site, the flow is turned eastward toward Southcenter Boulevard. The sewer main crosses beneath Southcenter Boulevard and then turns northward. It appears the primary reason the sewer was extended to the west side of the Parkway site was to provide a future connection point for property to the west. Since the main was extended the longest possible route, it became relatively deep along the western side of the project. The existing 9 story building required a deep building sewer service to the basement and therefore the additional depth was justifiable. The new site plan locates a building over the existing sewer main. Therefore the sewer will have to be relocated. In December of 1994, we had Santana Excavating pot hole the 66 inch storm pipe to verify the sewer crossing proposed on the BAR drawings. Elevations of the 66 inch storm pipe and 12 inch do not allow a crossing to be made where we originally proposed. Therefore the sewer design has been revised to use the existing crossing at the western end of the site. We are proposing to saddle the existing sewer main after it crosses the 66 inch storm pipe. A new sewer line will then be constructed back to the east and then north to the existing main. This route has been selected because the deep trench along the base of the retaining wall created design problems. The longer run has resulted in flatter pipe slopes. The pipe slope exceeds the Storm Drainage Report March 13, 1995 Page 7 minimum slope requirements of DOE. There is not sufficient elevation to have a 0.1 foot drop across the manholes. The 0.2% slope will be maintained across the manholes. The existing sewer main will have to remain in operation during construction of the new main. This can be accomplished by setting a new manhole structure on the existing main at the lower connection point. The existing pipe will extend through the new structure and continue to convey the flow. From the manhole, new sewer pipe will be installed southward to the existing main. A new manhole will be set over the existing main at the higher connection point. Again the existing pipe will extend through the new manhole conveying the flow to the existing downstream pipes. The new sewer run will be tested and approved prior to routing the flows into them. Once approved, the existing pipe within the manhole will be removed and the manhole bottoms channeled to direct the flow into the new sewer pipe. Existing sewer pipes under the floor slab will be capped and abandoned. The existing pipes are approximately 17 feet deep. According to GeoEngineers, the pipes do not have to be removed. Therefore only the existing manhole structures within the building area will have to be removed. Water Service: A dead end 10 inch water main currently serves the Park Place site. The dead end line also appears to be the only service for the adjacent properties on the north and south side of Parkway Place. The water main enters the site from Southcenter Boulevard, just north of the center driveway. The water main has a pressure of approximately 150 psi, and therefore fire flow is not in question. The water main will be looped across the site. This is necessary to adequately provide the fire hydrant spacing. The existing dead end water main will have to be connected to another main so that the loop has two sources. This will allow sections of the main to be isolated for maintenance without shutting down the water supply for the entire system. A second feed is also required by the fire marshal. Since the BAR approval, we have been corresponding with Levitz Furniture and American National Insurance Company about extending a 10 inch public water main across their site. Levitz Furniture is leasing the site from American National Insurance. There is a 10 inch water main on the south boundary of the Levitz site. American National Insurance is the property owner, so approval to complete Storm Drainage Report March 13, 1995 Page 8 the work and granting of easements will require their authorization. A water main loop would benefit both Levitz and Parkway Place sites. Levitz is willing to allow the work and therefore it appears likely that American National Insurance Company will allow the water main loop to extend across their property. Temporary Erosion Control and Grading: One of the first tasks will be the demolition of the existing building. It is my understanding that the building will be demolished using a crane and wrecking ball. This process will require a relatively small area for stock piling the material and moving the construction equipment around the existing structure. During this phase, most of the existing asphalt paving will be retained. An area will be dedicated for stock piling the material. The area will be enclosed with filter fabric fence to prevent silt laden storm water run -off from entering the existing storm system. Since the material will consist of crushed brick, glass and concrete, siltation should not be a significant problem. After the building demolition is completed, construction of the retaining wall will commence. Material excavated for the wall construction will be placed on the building pads. Existing asphalt concrete paving below the building pads will remain. The contractor will break the existing paving so that water cannot accumulate at the interface. The top 12 inches of building pad will be capped with the crushed building material. Since the excavated material will be compacted immediately after placement and the existing asphalt concrete paving will remain, there should not be a significant amount of sediment generated. A wetland exists in the southwest corner, just outside the parking lot area. The wetland has been delineated by a wetland specialist and located by a field survey crew. Since the existing parking lot drains from west to east, storm water run -off control should not be a problem during construction. The new site plan has been designed so that new paving will not extend beyond the existing pavement in the vicinity of the wetland. A filter fabric fence should be installed prior to starting demolition so that the wetland can be clearly identified. The filter fabric fence will also prevent silt laden storm water from entering the wetland during construction. There is an existing ditch along the western edge of paving which conveys the hillside drainage to the north and south. The section which drains to the south flows into the wetland. Construction of the retaining wall and building pads will destroy the existing ditch. An interceptor swale will be constructed at the top of wall Storm Drainage Report March 13, 1995 Page 9 to convey the hillside drainage north and south. The interceptor swale will prevent storm water from flowing over the top of wall during construction and after the wall is completed. The section of swale draining southward will be tied back into the wetland, preserving the existing wetland hydrology. Filter fabric fence will be installed along the eastern limit of clearing. An interceptor swale will be constructed along the western side of filter fence. The swale will convey storm water run -off from the disturbed areas to sediment traps. This system should provide adequate protection for the downstream system. Crushed material from the existing building will be used to cap the building pads and graded parking areas. The crushed material will provide a surface which is resistant to erosion. Other Best Management Practices will also be implemented to reduce the impacts to off -site areas. These include wetting the demolition materials being crushed and graded areas to reduce dust, installing filter fabric material in catch basin grates, sweeping parking lot and road surfaces, delineating limits of clearing on the plans and installation of a rock construction entrance. Site grade will be established to produce a balanced earthwork volume. This will help reduce truck traffic outside the project area during construction. The existing asphalt paving will not be removed from the existing parking lot. Existing paving will be broken and fill placed directly on the surface. The top 3 inches of fill will be treated with cement. This will produce a surface which is very resistant to erosion. These measures represent the minimum requirements which will be shown on the construction documents. Final Drainage System: The off -site drainage tightline system will retain the same function as the existing site. Relocation of the 48 inch pipe will not change the flow characteristics of the system. If the northern 48 inch pipe system inlet capacity is exceeded, then the storm water will follow the existing overflow route. The new building has been located so that the north face does not extend into the existing overflow route. If there is a failure of the overflow route, storm water will flow overland to the Southcenter Boulevard system. The building will not be flooded if this occurs. Buildings have also been located outside the overflow route for the southern 54 inch pipe system. If the inlet capacity of the 54 inch pipe is exceeded, or there is a failure, storm water will flow overland to the wetland area. This is the same route followed under the existing site plan. The building will not be flooded if this situation occurs. Storm Drainage Report March 13, 1995 Page 10 A swale will be constructed along the top of retaining wall at the western slope. From the retaining wall high point, the swale will convey storm water north and south along the top. At the point where the retaining wall is no longer required, the swales will be connected into the existing ditches. Therefore the existing drainage courses will be preserved. This is critical for the southern drainage course since it supplies water to the wetland. Drainage from the new parking lot will be collected by the existing catch basins. Underground pipe from the new catch basins at the loading docks will convey the storm water to the existing storm drainage system. The existing storm drainage system discharges untreated storm water directly into the Southcenter Boulevard system. Since this is no longer an acceptable practice, oil /water separation vaults with a coalescing chamber will be installed at the existing discharge points. This method of water quality improvement is widely accepted for existing storm system retrofit in urban areas. The water quality vaults will be sized for a 6 month -24 hour storm event according to D.O.E. Storm Water Design Standards. Storm water flows greater than the 6 month -24 hour event will be routed around the vault in a bypass system. This assures the oils and sediment trapped within the vault are not flushed to the downstream system. There are existing storm drainage pipes located below the new floor slab. According to GeoEngineers, the pipes can be abandoned in place if there is at least 3 feet of cover. Abandoned pipes will be capped at the ends. Some sections of storm pipe may have to be removed where they cross structural walls. These locations will be identified on the structural plans. Catch basin structure located within the building footprint will be removed. JEA /cd KING COUNTY. WASHINGTON. SURFACE WATER DESIGN MANUAL FIGURE 3.S.1C 2 -YEAR 24 -HOUR ISOPLUVIALS 0• Witt ,Ji ft-14r 2 -YEAR 24 -HOUR PRECIPITATION 3.4 '1"i' ISOPLUVIALS OF 2 -YEAR 24 -HOUR TOTAL PRECIPITATION IN INCHES 0 1 2 3 4 3 6 7 6 MAIM 1+300,000 3.5.1 -8 L 1/90 .1 ....::•• IZ-4, -,,—...-:: ...-:..(1zo --• .4 .74 sz) . *? O4 .4 _.- ...,. 0) ,Iz, .. ,‘ ..-. • 1 '114 rii? i. 4,* ■ —4 % I-I'ST 000•00e tT G 9 re Z TO S3HONI NI NOlitfild1031:1d AVQ-L 1:IV3A-001. AO S1VIArl1dOSI tre -- N011V1Id1338c1 Ava-L EIV3A-001- s ;42 - — it=o-of 1VflNVNO1S3G 113.LVM 3DVASIIS NO.LONIHSVM A11%11103 DN1N N M AU AL KING COUNTY, WASHINGTON. SURFACE W ATER DESIGN FIGURE 3.5.11 100-YEAR 7-DAY 1SOPLUV1ALS _ 8.2 - 9.68'4 9.08.8 9 ir r 100-YEAR 7-DAY PRECIPITATION 3.4 ISOPLUVIALS OF 10YEAR 7-DAY TOTAL PRECIPITATION IN INCHES 0 1 2 3 4 5 6 1: 300,000 7 6 Mll•% 15. 14.0 13.c 3.5.1-14 C L ' 1••• ••• N 1/90 3/ 8/95 Bush, Roed & Hitchings, Inc. page 1 Parkway Place John E. Anderson, P.E. storm disk /94187 BASIN ID: B2 SCS METHODOLOGY TOTAL AREA RAINFALL TYPE PRECIPITATION TIME INTERVAL • TIME OF CONC ABSTRACTION COEFF: BASIN NAME: SOUTH 2.23 Acres USER1 1.33 inches 10.00 min 11.83 min 0.20 PEAK RATE: 0.57 cfs VOL: BASIN ID: B3 SCS METHODOLOGY TOTAL AREA • RAINFALL TYPE PRECIPITATION • TIME INTERVAL • TIME OF CONC • ABSTRACTION COEFF: 0.17 NAME: BASIN 1.92 Acres USER1 1.33 inches 10.00 min 11.83 min 0.20 PEAK RATE: 0.50 cfs VOL: BASIN ID: B4 SCS METHODOLOGY TOTAL AREA • RAINFALL TYPE PRECIPITATION TIME INTERVAL • TIME OF CONC ABSTRACTION COEFF: NAME: SUMMARY BASIN BASEFLOWS: 0.00 PERVIOUS AREA AREA..: 0.23 CN • 77.00 IMPERVIOUS AREA AREA..: 2.00 CN • 98.00 Ac -ft TIME: 460 BETWEEN BLDGS 0.15 BASEFLOWS: 0.00 PERVIOUS AREA AREA..: 0.19 CN • 77.00 IMPERVIOUS AREA AREA..: 1.73 CN • 98.00 Ac -ft TIME: 460 cfs Acres Acres min cfs Acres Acres min BASIN SOUTH OF WINNERS 1.75 Acres USER1 1.33 inches 10.00 min 9.17 min 0.20 PEAK RATE: 0.51 cfs VOL: BASEFLOWS: 0.00 cfs PERVIOUS AREA AREA..: 0.17 Acres CN • 77.00 IMPERVIOUS AREA AREA..: 1.58 Acres CN • 98.00 0.14 Ac -ft TIME: 460 min 3/ 8/95 Bush, Roed & Hitchings, Inc. page 2 Parkway Place John E. Anderson, P.E. storm disk /94187 BASIN ID: B5 SCS METHODOLOGY TOTAL AREA • RAINFALL TYPE • PRECIPITATION • TIME INTERVAL • TIME OF CONC • ABSTRACTION COEFF: BASIN SUMMARY NAME: NORTH BASIN 1.10 Acres USER1 1.33 inches 10.00 min 9.30 min 0.20 PEAK RATE: 0.32 cfs VOL: BASIN ID: F SCS METHODOLOGY TOTAL AREA • RAINFALL TYPE • PRECIPITATION • TIME INTERVAL • TIME OF CONC • ABSTRACTION COEFF: 0.08 BASEFLOWS: 0.00 cfs PERVIOUS AREA AREA..: 0.11 Acres CN • 77.00 IMPERVIOUS AREA AREA..: 0.99 Acres CN • 98.00 Ac -ft TIME: 460 min NAME: NORTH BASIN 1.10 Acres USER1 1.33 inches 10.00 min 9.30 min 0.20 PEAK RATE: 0.32 cfs VOL: BASIN ID: bl SBUH METHODOLOGY TOTAL AREA • RAINFALL TYPE • PRECIPITATION • TIME INTERVAL • TIME OF CONC ABSTRACTION COEFF: 0.08 NAME: wall 3.04 Acres USER1 3.90 inches 10.00 min 15.00 min 0.20 PEAK RATE: 0.88 cfs VOL: 0 BASEFLOWS: 0.00 cfs PERVIOUS AREA AREA..: 0.11 Acres CN • 77.00 IMPERVIOUS AREA AREA..: 0.99 Acres CN • 98.00 Ac -ft TIME: 460 min swale for 100 year BASEFLOWS: 0.00 cfs PERVIOUS AREA AREA..: 2.50 Acres CN • 77.00 IMPERVIOUS AREA AREA..: 0.00 Acres CN • 98.00 36 Ac -ft TIME: 480 min BUSH, ROED & HITCHINGS, INC. 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CIVIL ENGINEERS & LAND SURVEYORS 2009 Minor Avenue East Seattle, WA 98102 (206) 323-4144 (206) 323-7135 ' Fax .00.. B R H SHEET NO CALCULATED BY -116?11 CHECKED BY DATE SCALE OF DATE NEW: ?FE t.t.nu. 13g .5 /-b-77 rb A4,4-re4-1 77 /r/tA42 te,C1,4•147 IFEre....ilicEr) • Ti (_.4-ae:5.-r i550451^.1 /4612--5 Q A /211 /00,eio ApEottrru: A-REA5 Aeoz-E 7746 . . ...._ or- rzx tVozrill L) /W/ Gu c.c., as' 7-14147* "Tb ,Slz,"5D sc>t,_.) i(i0277#4 5/L'� e9 7.71 PRopp.Tzry, 77.07 7. LeE5 Afe..77- A/74-ve-- t/c- 77/er .01/11.(1A7-074 VA-14-7 F:66141 gccrf t7Rdso... rog 7-44 5cror-44 f4411.4, 7; czwvecy.a-r) Ib. -MF. is<igr LAf. ifir 1 7 . r-gerieg. TA .ezz ti-Ra4 Aior /h444-- 7. it,g bveuive-D /J 774e-- okikm7sZ, MAxv pie' Mn ivokril or 77k /O7/ 14/84- Nor te35 Ciat4087'), 77,16 mi/p1.4a-Ivr VeZ , 7/WI tAIE Aleit/65' 4107- Fizavroe-D ,4&) wt-1)1.--r i5'g 77-/S P°^ftri 764 Wen.79; ,Peryd.Ers7V-1/40,4 61.1r4 0141 k i 11CO MON A 3.51 Cftsrfm■ 1 slop.. (rtyr.t.12- 0..005 Sid. slop.. (721)■ 1. Welt Argon- 037 n 0.015 Wmt L'airimmtmr■ 1.82 scre.ftom width (ft)- Flow delEpth (rtj— 1 0.20 Cmloulftteld Flow (cros)-- 0-91.51. Flow Nrubloolty (A.1241)'" 2-4462 C. wag' tc4x4Y iwc.V.-04.rt-1-- *14 — \OD M..O'1 = 0 4ASe 44"4 DZCCvgAV \ "B k) 4 — s\4.4A.LE t3s. e-or-laza-ce fl= o.0%s ti■ = ,50470 ,•.111.>e 130-voiv\ 114. (...c>r,sc.iReTS. \/...mkt..e ,e)r.Jvs‘-( Ti-ie 100 \ra-niz C5Err1 <JA-r ),4-01F AT A Z744 ozcl c see CA LC Al3f-WES) t7sPot-IP-ele AT3:)\ie 03/08/95 RAINFALL PILE: STORM SEWER SUMMARY REPORT Parkway off -site syates FILE: 9487.STM 100 YEAR DESIGN STORK PAGE 1 OF 1 I - 0.000/ ( Tc + 0.000) ^ 0.000 LINE ID FLOW RATE INFO PIPE INPO 1 HYDRAULIC INFO LINE,' DESCRIPTION IINC ARIRUNOFFCIINLTIHEIINLT IIINC CIAI INPUTQ IUNIF0RMISIzE /IINVERT 'PIPE I NVAL IHGLSLOPEIHYD GRD 1 VEL I DOWNLINE/ 1TOT ARIWEIGHTDI Tc 1TOTL 11T0T CIA' TOTAL() 1FLOWCAPITYPE 1UP /DOWN 'LEW 11NVSLOP1 JLC 1UP /DOWN 1UP /DOWN 1 I (ac) I C 1 (sin) 1(in /11)1 (cfa) 1 (cfs) 1 (cts) 1(1n) I (ft) 1(ft) I(tt /it)I (!t /ft)l (ft) 1 (Pt /s) I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I OUTFALL 1 0.01 0.001 0.001 0.001 0.001 0.001 I 6601 16.501 10001 0.0131 0.0221 42.041 21.55 1 DNLN - 0 1 0.01 -man' 1.221 0.001 0.001 512.001 150.21 6601 14.501 1 0.0021 0.00 I 19.901 21.64 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1 2 1 66/48 JOINT 1 0.01 0.001 0.001 0.001 0.001 0.001 I 4801 22.511 9101 0.0131 0.0211 61.491 16.71 1 DHLN ■ 1 1 0.01 -maul 0.311 0.001 0.001 210.001 116.71 4801 16.501 1 0.0071 0.00 1 42.041 16.71 1 48DEND /HILL I DNLN - 2 1 4 1 66/54 JOINT 1 1 5 1 54 TO SILL 1 1 6 I 1 DNLN 1 DNLN 4 54 ON HILL. DNLN - 5 0.01 0.001 0.001 0.001 0.001 210.001 1 4801 69.001 3101 0.0131 0.0371 72.881 16.85 0.01 -mini 0.001 0.001 0.001 210.001 559.51 4801 22.511 1 0.1521 0.00 1 61.491 16.71 1 0.01 0.001 0.001 0.001 0.001 0.001 1 6601 16.581 401 0.0131 0.0081 42.371 12.71 0.01 -man! 0.341 0.001 0.001 302.001 150.21 6601 16.501 1 0.0021 0.00 1 42.041 12.71 1 1 1 1 1 1 1 1 1 1. 1 1 1 0.01 0.001 0.001 0.001 0.001 0.001 1 5401 16.581 1101 0.0131 0.0241 44.961 18.99 0.01 -man' 0.251 0.001 0.001 302.001 8.81 5401 16.581 1 0.0001 0.00 1 42.371 18.99 1 1 1 1 1 1 1 1 1 1 1 1 1 0.01 0.001 0.001 0.001 0.001 302.001 I 5401 69.001 2801 0.0131 0.1021 73.411 19.09 0.01 -nan' 0.001 0.001 0.001 302.001 858.51 5401 16.581 1 0.1911 0.00 I 44.961 18.99 r ��G 2.tr�fj(41Z (N t-X (5T1t- 0 GaG , 1 rj4‘ 4 " -1 F‘ N 1/2 LA c\ sQ.v L. 1-0 Gut✓v -�, G2o�sl tila 54' comb e S F = 302 GV S s r s -row l e4r 1,1,/42 = 61.4t71- 22, sr= .38,6/8 Fr -7 z-r 8 or Neu F�,� r48 sD PRe55ufZE = 39,Qf3 r -rte 2. ?)6g r psci ' /50 psi 5ood 661/4e1). = 42, 04'-- /Cogs' fY g s' = e 5 , 5 f Fr PQv-veE = .S.54Fr 2,30844 59 ps/ < 150psi 66H/4 gIt6,.,NE6,--rto►.l i i i ft - CAST (Zpu{5 MN C / W� AST Tor s%c s'oN Car.3c. 13e:T'.JE Wet 4T7W &:5.)-t-- tt.l P(. -PC.0 'o-Ctovo / ,• ¢8" Foe Acc.64`2 GAy� (N ‘se tA \' w P,ot -t 17 ou3r4 1.--t 1„,10.1) t0 NP've CL-ty a- 5 VtT r out oe ulttw 46'->r-7 Bye /N My 1'b EXTEW IN7b CAS - /ev -PLACE f3A5C SbC.-11o� 7/4 8 " ,j, I e(r7 `1 d'a or Gb" egeAug MI-4 mu L e,,em 440)40 17(.,Fo1 Vrgv,-) 98'(dEw9 City of Tukwila John W. Rants, Mayor April 10, 1995 Department of Community Development Steve Lancaster, Director Mr. Roy Bennion Park Place Associates 800 Fifth Avenue Suite 3700 Seattle, Washington 98104 Re: Parkway Place Dear Mr. Bennion: In enforcing the SEPA conditions attached to this project with respect to noise and nuisances, the following decision has been made. We will enforce a 70 dB(A) limit on noise associated with demolition and construction for this project. This is the maximum noise level permitted under state and local codes for noise levels from an industrial property to an industrial property, and as such is the maximum permitted noise level under ordinary circumstances. If we receive complaints in the department on noise levels associated with demolition or construction, we will ask that the contractor on the project hire a qualified professional to measure noise levels at the appropriate property line of the complaining property. If the noise levels exceed the 70 dB(A) limit, we will consider mitigation at that time. I would suggest that you take the following steps to minimize any demolition /construction delays in the event a complaint is received: 1. Make arrangements with a qualified environmental noise specialist to be 'on call' so that should a complaint be recieved, quick response can occur. It would be helpful if you could inform us of your arrangements and provide information on the individual's qualifications. 2. Identify alternative measures that can be taken or attempted to reduce noise levels in the event it is determined that the standard referenced in this letter is exceeded. Sincerely, Steve Lancaster, Director Department of Community Development 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431 -3665 .... � .. .... . cc Blayne Leingang R.W. Rhine Duane Griffin, City of Tukwila Ron Cameron, City of Tukwila Facsimile Cover Sheet To: Diana Painter Company: City of Tukwila Phone: 431 -3661 Fax: 431 -3665 From: Michael Woodland Phone: 467 -4806 Fax: 621 -8782 Date: 23 February 1995 Pages (including this cover page): 14 Comments: RECEIVED FEB 2 4 1995 COMMUNITY DEVELOPMENT Diana, Included here is a draft of the complete SEPA report. I am also putting a copy in the mail along with some material from PSAPCA. Look the report over and tell me if it addresses the elements and code requirements in the level of detail you wanted. Is there any thing else that should be included? In addition, I have several questions relating to the notes you made concerning elements. I've included a copy of your notes here as well. The questions are as follows: • I didn't write anything for the element on aesthetics on retaining wall detailing. There wasn't much definition of this by the time the report was issued. There still isn't as far as I know. Am I missing something? • There is nothing on noise for the element on Environmental Health. Except for not restating allowable dB(A), I thought the Checklist covered it sufficiently. Do you have some elaboration? • There is nothing in the element on transportation regarding "No intersection impact analysis" or "Provide ped access ". I have no documentation on these issues. Can you fill me in? • The element on utilities does not cover "shoring up the wall while utilities are relocated" because I'm not sure of the reference. Is this the bracing ]FAXED • • across to the new building mentioned in the 21 Dec report from Geo Engineering? If so it follows the date of the SEPA report and is covered in the 17 Jan addendum. Is that sufficient? • The element on utilities also does not cover interference with the WSDOT storm line. I have no documentation on this issue. • The code requirements section included a note regarding "Utilities etc. ". What would you like here? Required utilities permits /approvals include Sanitary Side Sewer, Storm Drainage, and Water. Is there a summary of thes " that would be useful? Michael Earth Air for2, E. pa_ ;Kcaw:T Mention excavation of hillside Discuss erosion control (says will do it during dry months, in January?) Discuss impacts of crushing operation, demolition Surface water No surface water impacts. See below. Ground water Ground water on the site flows generally to the northwest. This would indicate that demolition and construction activities would have minimal impact to the classified watercourse in the northeast corner of the site. According to the SEPA Checklist, the closest construction activity to this watercourse is 70'. Vegetation Mention trees removed from landscaping, trees removed from hillside, tree replacement plan and vegetated wetland buffer Noise Mention noise during grading, construction, demolition, crushing Environmental health Mention asbestos in referenced in report Aesthetics Mention detailing of wall Transportation Problems with trip generation analysis No intersection impact analysis Transit stop /shelter to be retained Provide ped access Utilities Mention need for shoring up wall while utilities relocated. Mention coordination between storm sewer relocation and interference with WSDOT storm drainage line. mention new easements per conditions 8 2/20/95 5 :13 PM CITY OF TUKWILA MITIGATED DETERMINATION OF NON - SIGNIFICANCE PROJECT: Parkway Place DATE: December 1, 1994 PROPOSAL: To demolish a 9 -story office building and construction 150,000 sq. ft. of retail space LOCATION: 17501 Southcenter Parkway APPLICANT: Howard Turner, Architect, Turner & Associates Michael Sandorffy, Developer, Park Place Partners FILE NUMBER: L94 -0085 SEPA THRESHOLD DETERMINATION: Mitigated Determination of Non - significance Issued December 1, 1994 ENVIRONMENTAL REVIEW RECORD The environmental review of this proposal consisted o an analysis based on the following documents included in the environmental record: A. SEPA Checklist, revised, dated November 10, 1994 B. Report from Arthur D. Little, "Environmental Baseline Assessment," April 29, 1993 C. Letter from Peter Jowise, Herrera Environmental Consultants, "Parkway Plaza Building Inspection," October 29, 1993 D. Report from Envirobusiness, Inc., "Phase II Limited Subsurface Investigation," November 12, 1993 E. Letter from Mark Jacobs, TP &E, "Parkway Place Boeing Site Trip Generation Study," September 15, 1994 F. Letter from Blayne Leingag, R.W. Rhine, "Parkway Plaza Building; Demolition," September 23, 1994 Page 1 G. Letter from Michael Sandorffy, Parkway Place Partners, "Canopy Removal," October 31, 1994 H. Report from Talasaea Consultant, "Parkway Place Retail Center Sensitive Areas Ordinance Report," November 1994 I. Letter from Blayne Leingang, R.W. Rhine, "Parkway Place," November 7, 1994 J. Letter from Mark Jacobs, TP &E, "Parkway Place Boeing Site Midday Trip Generation," November 9, 1994 K. Letter from Shawn Parson, LandPlan, "Parkway Place," November 10, 1994 L. Report from GeoEngineers, "Report, Geotechnical Engineering Services, Proposed Parkway Place," November 10, 1994 M. Report from Bush, Roed & Hitchings, "Preliminary Report for BAR Review,: November 10, 1994 N. Letter from Michael Sandorffy, Parkway Place Partners, "Canopy Removal," November 10, 1994 O. Plans and Drawings by Howard Turner & Associates, November 10, 1994 P. Letter from Ron Cameron, City of Tukwila Public Works, "Parkway Place," November 18, 1994 Q. Letter from Paul Grant, Shannon & Wilson, "Geotechnical Review, Proposed Parkway Place Retail Center," November 28, 1994 R. Letter from Doug Johnson, Metro, "Transit Issues and the Parkway Place Retail Center," November 28, 1994 S. Letter from Gary Schulz, City of Tukwila Department of Community Development, "Parkway Place Retail Center Preliminary Environmental Review," November, 28, 1994 T. Conversation between Dale Morimoto, Environmental Program Manager, WSDOT, and Diana Painter, November 29, 1994 U. Conversation between Bob Kimmerling, Materials Laboratory, WSDOT, and Diana Painter, December 1, 1994 DESCRIPTION OF'I'HE PROPOSAL Proposal: The applicant proposes demolishing a 216,000 square feet of office space and construction approximately 150,000 square feet of retail space. Existing site: A nine -story concrete slab and beam, brick -clad office building currently exists on the site. It is sited in the center of the 15 acre site, surrounded by parking and flanked on the northeast and southeast corners (originally part of this parcel) by two restaurants. A cooperative parking arrangement exists between the restaurants and the owner of this property. The west half of the site consists of a wooded hillside with two drainage ways, draining from west to east, and into the existing storm sewer system. Surrounding land use: Retail businesses and restaurants exist north of the site; a warehouse /retail outlet is located on the southern boundary; to the east is Southcenter Parkway, which provides access to the site, with retail businesses across the street; and to the west is the right -of -way to Interstate 5. Page 2 Project description: Demolition of the existing office building involves salvaging the brick and steel, and recycling other building materials by crushing them and using them for fill in what is now the basement of the existing office building. The next phase of the project involves excavating and constructing a 5' to 36' retaining wall at what is now the toe of the existing slope, on the west edge of an abandoned railroad bed. Soil from this excavation will also be used for fill on -site. The next phase involves re- location of utilities where applicable. The most significant re- location will be a 48" pressurized storm sewer line, which is located under the footprint of the proposed building. Two one -story concrete tilt -up structures will be constructed on the site, ranging in height from 26' to 48'. One approximately 32,000 square foot retail store will be located on the southern portion of the site. The larger structure, approximately 125,000 square feet, will house three retail outlets. The structures will be site from 220' to 375' west of the Southcenter Parkway, but will be oriented toward the Parkway. Some of the existing parking area and mature landscaping will be retained. Other portions of the parking lot will be re- striped, and new landscaping added. Oil water coalescing plates will be installed in the storm system for all parking areas. New landscaping will be added, and some re- forestation of the hillside will be undertaken. Access: Existing access to the site will be retained. The primary entry will be at the center of the eastern boundary, where there is a traffic signal. Secondary entries are located at the northeast and southeast corners of the site, and will also be retained. These will serve as truck and fire access for the new project, as well as access to the existing restaurants. An existing bus stop and bus shelter in the northeast corner of the site will remain. Sensitive areas: Classified sensitive areas on the site include Class 3 slopes from the railroad bed to the western boundary of the site; a Class II wetland at the south end of the property; and a Type 2 Watercourse near the north boundary of the property. A portion of the slope will be excavated in conjunction with this project and retained with a soldier pile retaining wall. Erosion controls and revegetation will be required in conjunction with construction. The wetland will be protected with a 25' vegetated buffer. The watercourse will not be affected by this project. Page 3 PRINCIPAL CHECKLIST ITEMS 1. EARTH Excavation of Hillside- In response to question B. le the SEPA Checklist notes that "8- 10,000 cubic yards of soil will be removed from the hillside and placed as fill". This excavation is part of work intended to increase the level area on the site and could actually involve as much as 14,000 cubic yards of cut from the hillside. Retaining Wall- A retaining structure would be constructed to stabilize the exposed surface of the excavation. As originally proposed, the structure would be a tied -back soldier pile wall approximately 700 feet long and varying in height between 5 and 36 feet depending on topography. A 48" storm sewer, currently located at the toe of the slope and running north - south, will be relocated so that its centerline is approximately 10 feet east of the new wall. In a report dated 10 November 1994 (document "L "), the applicant's engineer recommended that the wall be constructed as follows: The soldier piles should be embedded a minimum of 15 feet below the planned base of excavation. Passive resistance available on the piles extending below the level of excavation was determined using an equivalent fluid density of 300 pounds per cubic foot applied to a width equal to 2.5 times the diameter of the piles or the spacing between the piles, whichever is less. As the excavation progresses downward, timber lagging would be installed between the soldier piles to limit spalling and loosening of soil in back of the wall and to provide a smooth surface against which to place drainage material. The permanent facing for the wall (such as cast -in- place, precast, or sprayed concrete) would then be installed against the drainage material. (This Mitigated DNS requires, among other conditions, that concrete facing be installed over the wood lagging.) Erosion Control- In response to question B.lh the SEPA Checklist notes that "Earthwork activities should be done during periods of dry or intermittently wet weather ". Given that the project is constrained by a very tight schedule that anticipates construction beginning in early spring it appears unlikely that earthwork activities could be accomplished during other than wet weather. Accordingly, careful adherence to effective measures for the control of erosion is very important. A set of measures are detailed by a report from Bush, Roed, & Hitchings, November 10, 1994 (document "M"). They include erecting a filter fabric fence around the existing structure as well as the delineated wetland areas during demolition, constructing an interceptor swale along the top of the retaining wall so that drainage is carried north and south, installing a filter fabric fence and interceptor swale along the eastern limit of clearing so that run -off is carried to sediment traps, wetting demolition materials before crushing, installing filter fabric material in catch basin grates, sweeping paved surfaces, delineating limits of clearing on the plans, and installation of a rock construction entrance. 2. AIR Demolition- The demolition of the existing office building carries the potential of significant dust emissions to the air. The proposal includes salvaging as much of the building as possible, demolishing Page 4 the shell, and crushing the remaining material small enough to be used as fill on -site. The process is expected to begin during the winter months and last approximately 60 days. Off -site hauling will include disposal of wood, carpet, sheet rock, ceilings, and structural steel. Hauling should generate approximately 100 two way trips and result in no more than 12 loads per day. Concrete will be crushed on -site by machinery that includes built in water misting. No indication is given of the volumes of water used for misting nor how the waste water will be processed. The reply to question B.2c outlines a variety of measures for the control of emissions to the air including spraying of dust suppressants, truck preparation and cleaning, and misting with water. However, the wording is not clear as to which, if any measures will be followed. 3. WATER Surface and Ground water- Surface and ground water on the site flows generally to the northeast. This indicates that demolition and construction activities should have minimal impact to the classified watercourse in the northwest corner of the site or the type II wetland at the southwest corner. According to question B.3a(2), of the SEPA Checklist, the closest construction activity to the watercourse is 70' down hill and to the southeast. 4. PLANTS Tree Removal and Replacement Plan- Western portions of the site are designated by the City's Sensitive Area Inventory as a Sensitive Area -Class 3 slope. Consequently, the City's Interim Tree Ordinance applies to any removal of trees carried out in preparation for excavation of the site's western hillside. The applicant submitted a tree replacement proposal based on Tree Ordinance Section 7.9 Exceptions. The Exception uses tree canopy cover guidelines for the project's overall tree retention and replacement. The proposal is detailed in documents "G ", "H", "K ", and "N". In exchange for 25,752 square feet of tree canopy removed at the toe of the slope, the project will include a tree replacement area of approximately 12,500 square feet containing 103 1' -2' saplings consisting of a mixture of 2/3 Douglas fir and 1/3 big -leaf maple. The area is located along the western boundary of the site. This is deemed an appropriate exchange because, while the adjacent hillside is an older, "climax- type" growth of mixed Douglas fir and big -leaf maple; the vegetation on -site is younger, "pioneer- type" growth composed mostly of big -leaf maple, red alder, and some black cottonwood. The action removes lower value vegetation and replaces it with more desirable plantings. In addition to tree removal on the western portions of the site, a large number of mature ornamental trees will be removed from planting areas in the existing parking area. This will occur because of one or more of three reasons: the poor condition of some of the trees, the location of new buildings, and revisions to parking aisles required by current parking codes. None of the trees lost from the parking area are subject to the City's Interim Tree Ordinance and are not subject to replacement. Page 5 Wetland Buffer- The Type II wetland identified by item 3. Water is insulated from the project by a 25 foot vegetated buffer. The buffer area will be planted with a mixture of Washington or Polack hawthorn and willow. Trees planted in this area are not part of the project's Tree Replacement Plan. 7. ENVIRONMENTAL HEALTH Asbestos- A background report (Document "C ") on the existing office building prepared by Herrera Environmental Consultants (signed by Peter Jowise and dated 29 October, 1993) states that asbestos - containing materials in the building may include "...several types of vinyl sheet flooring, floor and cove mastic, gypsum board (drywall), and joint compound." If these materials are not completely removed from the building there is a possibility that asbestos may become airborne during the process of demolition and the grading of the rubble. PASAPCA regulations require asbestos removal by a certified asbestos abatement contractor. 14. TRANSPORTATION Trip Generation Analysis - In response to question B.14f the SEPA Checklist notes that "No new trips per day or during the AM, Noon, or PM peaks are expected". This means that the proposed 167,000 square feet of retail space will generate less traffic to the surrounding urban area than the 2,227 employees of the now unused office building. This conclusion follows from the assumption that most driveway trips result from "pass -by" or "diverted linked" trips. These are trips that come from existing traffic, that is drivers already in the area for other shopping reasons. The applicant asserts that PM peak trips are more significant for retail uses than Noon trips. Assumptions for trip generation for the project are based on the Institute of Transportation Engineers (ITE) Trip Generation, Fifth Edition, 1991. The calculations were verified by Ron Cameron (City of Tukwila, Dept. of Public Works) and noted in a memo dated 18 November, 1994. Pedestrian Circulation - In response to question B.14b the SEPA Checklist notes that no buses stop in front of the property. There is, in fact, a bus stop and shelter on Southcenter Parkway located at the southeast corner of the property. The SEPA Conditions require retention of the stop and shelter. 16. UTILITIES Storm Sewer Relocation- According to a memo by Ron Cameron (City of Tukwila, Dept. of Public Works) dated 18 November, 1994 the relocation of the 48 inch storm sewer must take into account several issues. Among them, he notes that the line is pressurized and so must be concrete, approval must be sought if the existing line is reused and a surface water drainage plan maintaining continuous flow is required. Easements- According to a memo by Ron Cameron (City of Tukwila, Dept. of Public Works) dated 18 November 1994, storm, sewer, and water lines must be provided with new easements where they Page 6 are public and these must be recorded. This also applies to relocated lines. Where easements are not needed they should be abandoned. MITIGATED CONDITIONS OF APPROVAL Issuance of a Mitigated Determination of Non - significance for this project is appropriate, as no probable significant adverse impacts on the environment can be foreseen as a result of this project. The following mitigation measures are required as a part of this project: 1. New easements must be provided and recorded for storm, water and sewer lines that are for public or mutual use. New easements must be provided for all utilities that are relocated in conjunction with this project. New easements must include abandonment of existing easements where applicable. 2. The peer review consultant retained by the City, Shannon & Wilson, reviewed the geotechnical report for the project. Specific recommendations by Shannon & Wilson with respect to wall design for hillside stability will be followed in conjunction with applicable permits. This includes, but is not limited to, the use of a tied -back soldier pile wall, three -foot minimum freeboard, and concrete facing over wood lagging on the wall (verbal recommendation from Paul Grant, 11- 29 -94). 3. The conditions established by the City Urban Environmentalist, Gary Schulz, and documented in his letter of November 28, 1994, will be followed with respect to implementation of the City tree regulations (TMC 18.54) and Sensitive Areas Ordinance (TMC 18.45) in conjunction with applicable permits. 4. Storm water drainage will be accommodated per recommendation of the City Department of Public Works. 5. The transit stop and shelter adjacent to the project must be retained. 6. The ability to comply with City noise and nuisance ordinances (TMC 8.22 and 8.28) must be demonstrated for planned grading, demolition, crushing and construction activities. 7. The ability to comply with City ordinances governing asbestos removal must demonstrated for planned asbestos removal. 8. It must be demonstrated that construction of the new 48" storm sewer will not undermine the stability of the retaining wall in conjunction with applicable permits. Page 7 CODE REQUIREMENTS The following code requirements apply to this project, and are included here as background information only. For complete restrictions and requirements refer to applicable codes and ordinances. Tree Clearing Ordinance (City of Tukwila Ordinance 1715) A permit is required for tree clearing only within Sensitive Areas or Sensitive Area Buffers. The Tree Clearing permit application must include a site plan identifying the location, size and species of all trees, with a diameter of 4" or more. Also required is a landscape plan showing the location, size and species of proposed replacement trees. The plan must be reviewed by a professional and must identify mitigation measures and a time schedule for the work. (The DCD Director may stipulate additional requirements or may waive or modify the existing requirements.) An application fee is required to cover costs of permit processing. The DCD Director may require insurance coverage if the work might present a hazard to people or property. The Director may also require some means of financial security if the possibility exists of unauthorized clearing in association with the work. Permit approval depends on several criteria. The design should retain as many trees as possible; protect retained trees against damage during work; minimize impacts to the surrounding environment; and where trees are being relocated, utilize best management practices. A final criterion relates to the ratio of trees removed to trees replaced. For each tree removed of 4" to 8" in diameter, one replacement tree should be planted; for each tree removed of 8" to 12" in diameter, two replacement trees should be planted; for each tree removed of 12" to 18" in diameter, four replacement trees should be planted; for each tree removed of 18" to 24" in diameter, six replacement trees should be planted; for each tree removed of 24" or more in diameter, eight replacement trees should be planted. Replacement trees shall be a minimum of 2 -1/2" caliper if deciduous or 6' -8' in height if evergreen and shall not exceed a density of 70 per acre. If these requirements cause undue hardship an application may be made for an exception in the calculation of retention and replacement of trees. Where sites have dense stands of trees the DCD Director may allow the "canopy cover" approach to calculations. In this case canopy cover of each new tree shall be calculated at 314 square feet. Sensitive Areas Overlay Zone (TMC 18.45) A number of environmental conditions including presence of wetlands, watercourses, or potential geologic instability may cause an area to be categorized as a Sensitive Area. Wetlands and watercourses are rated Type 1, Type 2, or Type 3 according to sensitivity. These Areas and ratings are shown on the City of Tukwila, Sensitive Areas Maps, 1990. If a site or portion of a site is zoned as a sensitive area certain restrictions apply. These include very limited allowable uses and a requirement for Sensitive Area Buffers. Buffer widths for wetlands are 100' for Type 1, 50' for Type 2, and 25' for Type 3. Buffer widths for watercourses are 75' for Type 1, 35' for Type 2, and 15' for Type 3. Buffers for Areas of Potential Geologic Instability are determined on a case -by -case basis. In addition, Page 8 a setback of 15' is required for all commercial developments. Buffers and setbacks may be decreased or increased by the DCD Director. When an application is made for a building permit or land use review, the location of any sensitive areas and buffers must be indicated on the site plan. Several procedures apply to the process if a sensitive area is identified. These include: a requirement for a Sensitive Areas study, denial of development if potential costs and dangers cannot be minimized or mitigated, a pre - development conference, site monitoring by a specialist, and identification of the boundary between a sensitive area and its buffer by fencing, a sign, or both. Land- Altering Ordinance (TMC 16.54) To control erosion and sedimentation the City of Tukwila requires a permit for any land- altering activity. This permit applies to activities that that may cause sedimentation or result in a change in a site's natural cover or topography. An application for a land- altering permit may include the following: • A site map and land - altering plan that includes existing and proposed topography, existing and proposed drainage facilities and protective devices, location of proposed excavations and fills, and the work schedule. • An interim erosion and sediment control plan that addresses surface run -off and measures to retain sediment and control erosion. • An final erosion and sediment control plan that addresses surface run -off and measures to retain sediment and oil as well as control erosion. • A maintenance schedule for permanent erosion control facilities that is binding on all subsequent owners of the property. • A work schedule detailing when land- alterations will occur and construction cost estimates for use in determining amounts for required securities. • A soils engineering report that addresses soil qualities and conclusions and recommendations regarding procedures and design. • An Environmental Checklist and completed environmental review. • A performance bond and • Supplemental materials as deemed necessary by the Public Works Director. The Public Works Director may waive any or all of these. A fee to cover the cost of plan review is charged for a land- altering permit. The permit is issued within 40 days of submission of an application provided that the application is consistent with the ordinance. The Public Works Director must be notified within the 48 hour period prior to beginning a land- altering activity and the Director must be notified of completion of any control measures within 48 hours of their completion. Other standard permit requirements include: • Obtain permission in writing from the Public Works Director prior to modifying the control plan. • Maintain all drainage systems and control measures. • Repair any siltation or erosion damages resulting from the work. • Inspect the construction control measures once a week and make any needed repairs immediately. • Keep a copy of the control plan on -site. • Protect adjacent property and sensitive areas from damage during grading operations. Page 9 The proposed work shall be undertaken in accordance with certain mandatory standards including the following: • A permit is required for any land - altering activity. • All work must be done according to an approved land- altering plan. • A control zone that restricts all siltation and other adverse impacts must be established between a land - altering activity and any Sensitive Area Buffer • Any land- altering activity involving a surface area of more than 6,000 square feet must employ sedimentation and erosion control devices that meet the design standards of the King County, Surface Water Design Manual, King County Public Works Department, Surface Water Management Division, January, 1990. • Required vegetative groundcover shall be planted within 30 days following the completion of construction. Noise Ordinance (TMC 8.22) The City has an established policy to minimize the exposure of citizens to the dangers of excessive noise. It is also the express intent of the City Council to control the level of noise in a manner that promotes commerce; the use, value, and enjoyment of property; sleep and repose; and the quality of the environment. It is unlawful to permit a sound of more than 60 dB(A) to intrude upon a commercially zoned piece of property from another commercially zoned property. Variances may be granted following consideration of the relative interests of the applicant, neighboring property owners, and the general public. Puget Sound Air Pollution Control Agency (PSAPCA Regulations I & II) PSAPCA is the primary agency enforcing federal, state, and local air pollution standards, laws, and regulations in King , Kitsap, Pierce, and Snohomish counties. PSAPCA's major concerns include carbon monoxide, particulate matter, low- altitude ozone, and air toxics. The demolition of buildings comes under the jurisdiction of PSAPCA as a result of possible dust and asbestos emissions. Regulation I, article 9 of PSAPCA makes it unlawful to allow the uncontrolled emissions of dust. Regulation III, article 4 of PSAPCA makes it unlawful to demolish a building unless all asbestos - containing materials have been removed. Before a building can be demolished an "Application to Perform a Demolition" and a $25 fee must be submitted to PSAPCA. If no asbestos is present, the application must also include a survey conducted by an AHERA certified building inspector that verifies the building as asbestos free. If asbestos is present then an "Application to Perform an Asbestos Project" must first be filed by an asbestos contractor. Abatement should then be conducted and followed by submission of an "Application to Perform a Demolition ". Page 10 ADDENDUM: Retaining Wall (17 January, 1995) Subsequent to the issuance of the Environmental Checklist there has been some difference of opinion between the applicant and the City regarding the design of the retaining wall at the rear of the site. In a report dated 21 December 1994, the applicant's engineer made several supplementary recommendations. Among these, the engineer asserts that treated timber lagging would provide a satisfactory permanent facing for the wall; that even without concrete facing a 50 -year life warranty could be provided. The engineer also reduces the assumption for equivalent fluid pressure from 300 pounds per cubic foot to 250 pounds per cubic foot. In addressing concerns about the proximity of the storm sewer the engineer suggests that, during construction, no more than 20 feet of the trench should be open at one time. Additionally, open portions of the trench should be supported by a braced support system and any future excavation should be accompanied by bracing extending from the base of the exposed portion of the soldier piles across the trench and bearing against the future building. In replying to these supplementary recommendations the peer review consultant working for the City of Tukwila, Shannon & Wilson, Inc., took issue with two important points. A report dated 5 January 1995 suggests that the construction process for the 48" storm sewer will significantly compromise the passive resistance available for the wall. Shannon & Wilson, Inc. instead suggest that the design assume that the lateral support the wall is provided not at the parking level but by the base of the excavation for the sewer line. This would require an additional row of tie - backs. Furthermore, the report disagrees that treated wood lagging is an adequate facing material. Shannon & Wilson, Inc. stress the importance of using shotcrete or preformed concrete panels as facing material for the wall. In a memo dated 10 January, 1995, Ron Cameron (City of Tukwila, Dept. of Public Works) confirmed the opinions of the City's peer review consultant regarding assumptions for passive resistance and facing materials. He also noted that WSDOT standards require concrete. A second memo, dated 12 January, 1995, by Gary Shulz (City of Tukwila, Dept. of Community Development) also concurs with the recommendations of the peer review consultant. In addition, he recapitulates Checklist condition number 8 which cautions against compromises to retaining wall stability caused by relocation of the sewer line and he points out that there may be liability issues for the city if the storm sewer is installed using special techniques. The applicant was officially informed of the City's support of these opinions in a letter dated 24 January, 1995 by Jack Pace, acting chair, Development Review Committee, City of Tukwila. During a meeting on the 27th of January, 1995 between City staff and the applicant's engineer, some reconciliation was established between the different positions. Shotcrete reinforced with wire mesh and sprayed directly on the excavated hillside is being considered by the applicant for the retaining wall. The City is not requiring wood lagging as part of the wall design. In addition, the applicant is examining the possibility of relocating the storm sewer line to the east side of the new building. If this is not possible then passive resistance for the wall will be assumed to begin at the level of the trench bottom and an additional row of tie -backs will be added. Page 11 MITIGATED CONDITIONS OF APPROVAL Issuance of a Mitigated Determination of Non - significance for this, project,is appropriate, as no probable significant adverse impacts on the environment can be foreseen as a result of this project. The following mitigation measures are required. as a part of this project: 1. New easements must be provided and recorded for storm, water and sewer lines that are for public or mutual use. New easements must be provided for all utilities that are relocated in conjunction with this project. New easements must include abandonment of existing easements where applicable. 2. The peer review consultant retained by the City, Shannon & Wilson, reviewed the geotechnical report for the project. Specific recommendations by Shannon & Wilson with respect to wall design for hillside stability will be followed in conjunction with applicable permits. This includes, but is not limited to, the use of a tied -back soldier pile wall, three -foot minimum freeboard, and concrete facing over wood lagging on the wall (verbal recommendation from Paul Grant, 11- 29- 94)..... . 3. The conditions established by the City Urban Environmentalist, Gary Schulz, and documented in his letter of November 28, 1994, will be followed with respect to implementation of the City tree regulations (TMC 18.54) and Sensitive Areas Ordinance (TMC 18.45) in conjunction with applicable permits. 4. Storm water drainage will be 'accommodated per recommendation of the City Department of Public Works. 5. The transit stop and shelter adjacent to the project must be retained. 6. The ability to comply with City noise and nuisance ordinances (TMC 8.22 and 8.28) must be demonstrated for planned grading, demolition, crushing and construction activities. 7. The ability to comply .with. City ordinances governing .. asbestos removal must demonstrated for planned asbestos removal. 8. It must be demonstrated that construction of the new 48" storm sewer will not undermine the stability of the retaining wall in, conjunction with applicable permits. 5 s/94 10:04 k'A1 206 8 6050 12/01'94 19:58 IOW Wasfilntiton St.b. Osis rtmont of Transportation f Prom: GEOENGINEERS 2SDOT MATERIALS LR T. M. Allen/R. E. Kimmerling Field Operations Service Support Center Materials Laboratory Oeoteclunical Branch, 47365 THONe 586 -7659 3CAN 321 -7659 rwx 586 -4611 sCAN FAx 321 -4611 To; Bert Pschundcr GeoEngineers RE: Parkway Place Project Geotcchnical Engineer Report Review Comments 002 Memorandum December 1, 1994 M requested, we have reviewed the geotechnical report r the subject project as it relates to the proposed retaining wall to be constructed on the w st side of the site, below the nott)ibound lanes of Interstate 5 in Tukwila, Washington. The selection of a tied -back soldier pile wall as the prefc icd wall type appears. appropriate. We request the opportunity to review and o4nument on the plans and specilleations for the wall. We have no further commen4 at this time. If you have questions or require further information, pleai4e contact Robert Kinuucrling at 586 -7659 (SCAN 321 - 7659). TIvIA:rek REK �J 003 i i1 �ii • i • • Landscape Architecture November 10, 1994 Diana Painter, AICP Associate Planner City of Tukwila Dept. of Community Development 6300 Southcenter Boulevard, Suite #100 Tukwila, WA 98109 RE: Parkway Place Dear Ms. Painter: NOV 1 199 DEVELOP ivk• r In response to your letter dated October 31, 1994, to Mr. Howard Turner as per the subject site, I have assembled responses to various issues as related to the site's environmental and landscape architectural concerns.. LandPlan P.S. in concert with TALASAEA, Resource and Environmental planners, have addressed the site's sensitive areas and vegetative matters. Specifically, the following items are enclosed for your overall review: 1. Sensitive areas study report (conducted and assembled by TALASAEA) 2. Tree inventory and removal plan 3. Landscape /tree replacement plan In addition, a professional review and recommendation is submitted herein per city of Tukwila's Interim Tree Ordinance. 1. General observations of the site's existing ornamental plant materials is that such material is fair to poor in overall quality within the parking lot planters. Quality of plant material improves around the existing building and perimeters. Existing vegetation adjacent Southcenter Parkway is to be retained as well as a majority of the planters south of the existing driveway access. 6 0 0 Main Street Suite D, Edmonds, Washington 9 8 0 2 0 (206) 776-4932 (Fax) 774 -7803 Page 2 - Letter to Diana Painter of City of Tukwila RE: Parkway Place 2. Protection measures would be undertaken to provide protection during construction. Such measures would include fencing around a tree's "drip- line" and minimum cut/fill within a tree's root zone area. 3. The site's western four -acre area entitled Parcel "B" would have 25,752 square feet (s.f.) of existing vegetation disturbed. Such vegetation consists primarily of "pioneer" type species in plant succession ecological terminology. Because of the short lived nature of such species, 30 -40 years, a lower value is attributed. The removal of such vegetation is proposed to have the replacement trees as per "tree canopy" replacement ratio -- one tree per 314 square foot of removed vegetation, equaling 82 trees. Use of the "canopy" methodology was selected due to the dense nature of tree growth and steeply sloped portions of the "sensitive- slope" area. Specific on -site locations have been chosen for tree enhancement: "Climax type" species with a higher value are to be planted within a plateau area near the site southwest corner. Tree species include Big -leaf maple and Douglas fir species. Wetland buffer -type trees, hawthorns and willow trees, 29 or more scheduled to supplement a wetland buffer adjacent the site's wetland. An exception to the City's tree ordinance is requested. Justification to this request can be substantialed by the following: 1. Eleven of the site's 15 acres are in a developed state and provide a minimum aesthetic value. 2. The proposed removal of an additional 25,752 s.f along the site's west slope area has . minimum impact due to the nature of the vegetative material; e.g., alder and black cottonwood. 3. Total tree removal plant quantities remain consistent with the "canopy" criteria count of 82 separate trees. Size has been reduced within the native rectangular area within the southwest corner to better insure plant survival and rapid growth. Adjacent the site's wetlands area larger caliper size has been suggested, 3/4 -11/4" cal., to provide a more visible impact. 4. Existing plant material within planters are to be replaced with healthy "similar" species, 2- 2'/x" cal. This will provide great enhancement of the area which has current questionable tree viability. 5. The granting of the exception/standard reduction will not be detrimental to the public welfare or injurious to other property in the vicinity. Page 3 - Letter to Diana Painter of City of Tukwila RE: Parkway Place If you should have any questions or request additional information, please don't hesitate to call. Thank you. T. Shawn Parsons PrincipalRegistered Landscape Architect #307 cc: Roy Bennion, Parkplace Partner Howard Turner, Turner & Associates John Anderson, Bush, Roed, & Hitchings Bill Shiels, Talasaea Consultants City of Tukwila John W. Rants, Mayor Department of Community Development Rick Beeler, Director MEMORANDUM TO: Diana Painter, DCD Associate Planner FROM: Gary Schulz, DCD Urban Environmentalist DATE: November 28, 1994 RE: Parkway _Place Retail Center #L94 -0084 - Preliminary Environmental Review. I have reviewed the project site studies and planned proposals for this project. Also, I have visited much of the undeveloped portion of the site to provide recommendations for the SEPA file and BAR review. My comments focus on project compliance with the Sensitive Areas Ordinance (SAO, #1599) and the Interim Tree Ordinance ( #1715). This review includes 1) Sensitive areas study report, 2) Tree inventory & removal plan, 3) Landscape /tree replacement plan, 4) Geotechnical report, and 5) SEPA checklist. The following recommendations have been discussed with the Department of Community Development Director. SENSITIVE AREAS ORDINANCE/WETLAND ENHANCEMENT I. TMC Chapter 18.45.040 contains a provision to allow wetland buffer reduction when enhancement is appropriate and approved by the DCD Director. Because the on -site wetland buffer area has been altered and lacks significant native vegetation, the proposed reduction in . buffer width is appropriate. However, the applicant must apply the SAO requirements for wetland alterations separately from other site development modifications that require tree replacement by the Tree Ordinance. The buffer enhancement plan is considered conceptual and will be reviewed under the guidelines of the SAO. Tree replacement for loss on other areas of the site cannot be transferred to the wetland buffer zone. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 Parkway Place Memo November 28, 1994 Page 2 II. Site reconnaissance found additional wetland area extending off -site but just north of the delineated wetland on the site. Although the additional wetland area is off -site, the 50 -foot buffer zone is on the project site. A field measurement indicated that the buffer zone could extend about 20 feet onto the project site. Since the on -site buffer is part of an old railroad bed, it could be considered for buffer reduction with enhancement. M. Wetland boundary and buffer need to be identified on all site maps. A 15 -foot building setback line should be shown to extend from the outer edge of the proposed wetland buffer area (TMC 18.45.040). W. Following the standards of the SAO, the buffer enhancement plan will use native plants to incorporate diversity and function.' TMC 18.45.040 (c)(3)(A)(ii) states The plan must include a variety of native vegetation that improves the functional attributes of the buffer and provides additional protection for the wetland or watercourse functions and values. The proposed enhancement only includes two species, willow and hawthorn. v-TREE ORDINANC c 1 I. The applicant has submitted a tree replacement proposal based on Tree Ordinance Section 7.9 Exceptions. The Exception uses tree canopy cover guidelines for the project's overall tree retention and replacement. This replacement guideline is particularly appropriate because the area of trees to be removed is comprised of dense stands of trees. The dense composition of young trees would be costly to identify and map as "significant trees" on an individual basis. As discussed above, the tree canopy cover approach cannot utilize the wetland buffer area for replacement. However, it appears that most of the existing forested slope could be enhanced with native conifer tree species to add an evergreen component, and possibly provide long term slope stability. Two- to four -year old seedlings may be appropriate for forest enhancement plantings. The area where tree removal is to occur has at least four tree species. Sheet L1 Landscape/Tree Replacement Plan shows planting of only one species (bigleaf maple) in the Tree Replacement Area. The tree replacement plan should also incorporate more species diversity. Parkway Place Memo November 28, 1994 Page 3 II. As requested by Park Place Partners (Letter 10/31/94), tree removal was permitted on the site to accommodate the required geotechnical investigation. The written request was approved based on minimal tree disturbance including an 8 -foot wide cleared trail. The impacts appear to be greater than described and the area that was cleared for a trail ranges from 14 - 19 feet in width. In response to the City's concerns, a tree inventory for the permitted clearing was submitted by Park Place Partners (Letter 11/2/94). A total of fifty trees were inventoried and mapped as potential tree loss from the slope area. Tree removal and replacement for this disturbed area will be subject to the standards of the Tree Ordinance but not allowed the use of Section 7.9 Exceptions. Specifically, the disturbed area for geotechnical investigation will follow the tree replacement guidelines of Section 7.8 C. Detailed landscaping plans with specifications, planting notes, and performance measures ect. will be necessary for both wetland buffer enhancement and tree replacement. SEPA CONDITIONS I. If feasible, consider saving and relocating the higher quality trees from the existing landscape plantings. II. This is a new project with a large amount of impervious surface. Stormwater management plans should include detention and biofiltration using grass -lined swales and /or a water quality pond. If the entire site is to be re- developed, the standards of the King County Surface Water Design Manual should apply. cc: Rick Beeler, DCD Director • PARK PLACE PARTNERS 800 FIFTH AVENUE SUITE 3700 SEATTLE, WASHINGTON 98104 208/624 -1444 10 November 1994 Ms. Diana Painter, AICP Associate Planner City of Tukwila Dept. Of Community Development 6300 Southcenter Blvd.. Suite 100 Tukwila, Washington 98109 RE: Parkway Place Dear Ms. Painter: " 7-. ". V/V E 211 91994 DEVELOPMENT As we have discussed and in response to your October 31 letter to Mr. Howard Turner, strict compliance with City of Tukwila Ordinance 1715 creates undue hardship on the applicant with respect to project feasibility. Consequently, we are requesting by this letter combined with the request contained in the letter to you from Landplan P.S. dated November 10, 1994, that an exception under Ordinance 1715, Section 7.9 be granted, specifically under the Canopy cover provision 7.9(D)(1). We believe we comply with the exception requirements in Section 7.9(B), as outlined below. 1) The owners have signed letters of intent from tenants representing 155,000 square feet of building area. Howard Turner has designed the project to accommodate the tenants and the parking required by the code. Because the sensitive slope area to be removed contains a high tree count, too high to individually measure and plot each tree, we need to apply canopy cover conditions. If tree replacement were called for at the ratio of one tree per 314 SF (138 trees per acre) at a maximum of 70 trees per acre, we would have to add +51,400 SFof area for tree planting to replace the 25,752 SF of canopy lost from the steep slope. The resulting loss of building and parking area would jeopardize project feasibility. 2) The 25,752 SF of sensitive slope canopy to be removed is largely behind the proposed buildings and at a height lower than the proposed building. This will be mostly screened D: \W IN WORDIPARKPLAWREE.DOG 1 1/394 from public view. The site will remain over 20% canopy as a percent of total site required in 7.9 (D) (1). Even though not required by the ordinance, we have proposed extensive replanting on the site. Parking islands will be planted to code. An "island" area of 16,850 SF which buffers the wetlands area on the site's southwest corner will be landscaped and an unplanted and/or underplanted hillside bench of over 13,000 SF will be planted into maples and Douglas fir. The new (non parking lot) areas to be planted exceed the sensitive slope area canopy to be removed. We are excited by this plan because it enhances the wetlands buffer and considerably upgrades the visible trees along Tukwila's west bench. As reported in the Talasaea report dated 11/10/94, the old growth hillside was at one time predominantly maple and fir. The understory of existing stand of alder /cottonwood supports small maple. The proposed planting helps the existing natural process speed up, producing a healthy stand of "climax type" new trees for future generations to observe on the hillside. I believe this plan complies with all of the criteria listed in Section 5.2 of the Ordinance. 3) Public welfare is not impacted by the plan. Rather than a detriment, the plan enhances the visible hillside and brings the "flat" part of the site into code compliance. A long term benefit is provided. Strictly speaking, the site, when redeveloped, will contain approximately 27.4% canopy cover, considerably above the 20% criteria applied to canopy method criteria in section 7.9 (D) (1.). Technically, if exception is granted, no new planting would be required. We propose our plan to go beyond the required, but in a way our consultants believe will serve the site and surrounding areas best for the long term future. Therefore, we request the exception. Please contact me with any comments or questions. Sincerely PARK PLACE PARTNERS Bennion D \WINWORDPAAKPWC\7REE.DOC /11/3!94 PARK PLACE PARTNERS 800 FIFTH AVENUE SUITE 3700 SEATTLE, WASHINGTON 98104 206/624 -1444 31 October 1994 Ms. Diana Painter Associate Planner, City of Tukwila 6300 Southcenter Blvd. Tukwila, Washington 98188 RE: Parkway Place - Design Review # L94 -0084 17501 Southcenter Parkway Canopy Removal Dear Ms. Painter: NOV 1 sl 1994 DEVELOPivu_i . At the BAR hearing of last Friday, the 28th, City of Tukwila required various engineering and geo- technical investigations on the hillside to the west of the current office building. Accomplishing the soils tests will involve placement and movement of drilling equipment on the hillside. Removal of minor portions of the tree canopy will be necessary to place and move the drilling equipment. Please consider this letter a request for interim Exception under Section VII of the Tree Clearing Ordinance, Item 7.9. Parkway Place Partners will formally apply for a tree clearing permit once site redevelopment has been approved by City of Tukwila. All vegetation on the hillside in question was entirely removed within the last thirty years. The hillside naturally revegetated with various deciduous tree species including maple, cottonwood and alder. The stem count per acre is higher than current forest practices for managed native stands - higher than one stem per square foot in many areas. The applicant, Parkway Place Partners, has filed a plan for redevelopment of the site. Once project approval is received from City of Tukwila a very minor portion of the hillside will be removed. All removal of any vegetation will be in strict compliance with Ordinance 1715. Therefore, any vegetative removal in conjunction with geo- technical testing should be subject to the canopy removal permit we will apply for in conjunction with the redevelopment project. The following discussion addresses the three criteria for Exception under Section 7.9 of the Ordinance: 1. Strict compliance with the provisions of the ordinance will jeopardize project feasibility and reasonable use of the property. The testing required by the city and SEPA involves three drilling sites on the hillside. Pursuant to the timeline mandated by City of Tukwila, our work must be accomplished and results submitted to the city not later than November 10. Allowing one day for site testing and 5 business days for analysis and reporting, indicates our need for canopy removal approval not later than Thursday, November 3. BACITY.DOCJ11 /1/94 2. Removal, replacement and mitigative measures proposed arm consistent with Section 5.2 of the Ordinance. Most important is the fact that only a very minor portion of the canopy will be removed as a result of testing. The site crews will be directed by our representatives on site to remove as few stems as possible and to minimize the impact of machinery on vegetation. Visual impacts will not occur as the area in question is not visible to any residential area and is screened from traffic and other public exposure by the adjacent nine story office building. Increases in run-off and erosion will not likely occur, given the density of hillside vegetation and the proposed location of test sites. The drilling equipment will travel along a relatively flat topographic bench, changing course only to avoid tree removal, where necessary. The pathway created will be about 8 feet wide and 500 feet long. The canopy/trees subject to removal under the testing program will be classified and the location referenced on a site topographic map. Tree root systems will not be disturbed as the machinery will not excavate other than drilling sites. If allowed to revegetate, the portion of canopy removed would "in -fill" within a very short period of time and be unnoticeable after the spring `95 growing season. 3. Granting of the exception will not be injurious or detrimental to the public welfare. The testing will be beneficial to the public welfare because: 1) The testing will support the city mandate for responsible development 2) Testing will remove a very narrow strip of canopy, amounting to a "thinning" of the canopy. This is a desirable forest practice. 3) The trees removed will be in the area of proposed canopy removal once the retail project commences. The canopy removal will be mitigated on site per the requirements of Ordinance 1715. If you have any question or comments, please call. Coordinating the equipment and crews will require additional lead time; we will appreciate a timely response to our request for exemption. We Iook forward to working together with the City of Tukwila on this project. Sincerely, PARK PLACE PARTNERS e ACZTV.00ai I /V94 NOV 1 91994 t.: r DEVELOPMENT PRELIMINARY REPORT FOR BAR REVIEW PARKWAY PLACE REDEVELOPMENT TUKWILA, WASHINGTON BUSH, ROED & HITCHINGS 2009 MINOR AVENUE EAST SEATTLE, WA 98102 PHONE:(206) 323 -4144 CONTACT: JOHN E. ANDERSON, P.E. November 10, 1994 111io1g4 EXPIRES 12/1/0..., ...I Parkway Place is a 15.54 acre site as delineated on the architect's site plan. The project is located along Southcenter Boulevard in Tukwila, Washington. Located on the site is a 9 story office building which was occupied by Boeing. The tenant has moved out of the facility and the owner is looking to find a more viable use for the property. This proposal would demolish the existing building and construct approximately 3.5 acres of retail space on the property. There are several existing utility lines and easements across the site. We have used an ALTA survey and topographic information prepared by Chadwick Surveying and Engineering to determine how the utility lines would be routed through the site under the new layout. A new section has been added to this report to discuss the exiting utilities in more detail. This section has been added in response to the City of Tukwila letter dated October 31, 1994. The existing site is generally flat. A steep slope rises on the west side of the property to Interstate 5. The slope is covered with trees and thick underbrush. A railroad easement is located along the toe of slope. It is my understanding that the railroad easement vacation process is nearly completed. The 9 story building is located approximately midway between the railroad easement and Southcenter Boulevard. The existing building has a footprint of approximately 24,981 square feet. The remainder of the site is covered by asphalt parking and landscaping. Detailed surface area coverage calculation have been prepared and are shown on page 4 of this report. Two other building share the existing parking and access points to Southcenter Boulevard. Each of the buildings are located on segregated parcels and have not been included in the area count for the Parkway Place project. These structures are to be remain after the completion of the shopping center. Some grading of the parking area between the two building may be necessary for the construction of the new retail building. Final design will also require coordination of utility connections for the sewer and water main relocation. This subject will be discussed in more detail in the new section of the report. Redevelopment of this site will include the construction of two retail buildings. A 32,370 square foot building in the southwest corner and a 133,143 square foot building along the western boundary of the slope. The 133,143 square foot building will cover the area occupied by the existing 9 story office building. Some of the existing utility lines serving the site will have to be routed around the new buildings. This includes extending a water main loop around the west side of the new buildings, relocation of an existing 48 inch storm pipe and routing the existing sanitary sewer main around the east side of the buildings. The new buildings have been located so that the existing 66 and 54 inch storm drainage pipes from the southern off -site areas do not have to be relocated. Existing parking areas will the retained to the greatest possible extent. Some additional parking will be gained along the west side of the 133,143 square foot building with the relinquishment of the railroad easement. The new building has been located further west than the existing 9 story building. This will require construction of a retaining wall along the western margin of the site plan. Discussions with the owner have included using a solder pile wall or a soil nailed wall. The advantage of using this type of retaining structure is that it can be constructed with minimal disturbance to the areas above the top of wall. There is a public storm drainage system servicing the site from Southcenter Boulevard. Storm water will be collected in catch basins and conveyed using underground pipe. Much of the existing storm system in the vicinity of the existing building will be abandon. The site has been graded so that finished grade elevations around the new buildings are higher than the existing grade. Therefore the storm water will sheet flow to the existing catch basins located in the eastern parking areas. Loading docks on the western side of the buildings are the only locations where a new storm collection system will have to be installed. The proposed site plan reduces the net parking area by approximately 1.5 acres. Since the area subject to vehicular traffic will be reduce, there should be a corresponding improvement in storm water quality discharged to the downstream system. Oil /water separator vaults with coalescing chambers and high flow bypasses will also be installed to improve water quality prior to discharge to the downstream system. The site is served by public sewer. Redevelopment of the site to a retail center will significantly reduce the sanitary sewer discharge. The 9 story office building contained approximately 214,600 square feet of floor space and supported a population of approximately 2,230 people. The proposed 165,513 square feet of retail space will reduce the sewer discharge by approximately 31,650 gpd based on the D.O.E. Table No. 2 for new system design. Therefore redevelopment of this site to a retail facility will benefit the existing sewer system. SURFACE AREA COVERAGE Existing site: 676,948 SF IMPERVIOUS ROOF AREA IMPERVIOUS A.C. AREA IMPERVIOUS RAIL AREA PERVIOUS LANDSCAPE PERVIOUS WEST SLOPE (15.54 AC) Redeveloped site: 676,948 SF IMPERVIOUS ROOF AREA IMPERVIOUS A.C. AREA IMPERVIOUS RAIL AREA PERVIOUS LANDSCAPE PERVIOUS WEST SLOPE = 24,981 SF (0.57 AC) • 383,677 SF (8.81 AC) = 26,136 SF (0.6 AC) = 88,807 SF (2.04 AC) • 153,347 SF (3.52 AC) (15.54 AC) • 165,513 SF 318,344 SF = O AC = 57,967 SF • 135,124 SF (3.80 AC) (7.31 AC) (0.0 AC) (1.33 AC) (3.10 AC) 3 1' ADDITIONAL UTILITY INFORMATION Storm Drainage System: There are two major drainage courses draining beneath the Interstate 5 and conveyed through the site. The most northerly course discharges from a 48 inch culvert approximately 70 feet west of the northwest property corner. At the discharge point, a concrete energy dissipator with "V" notched weirs on the bottom side has been installed. Storm water flows east from the discharge in a 15 foot wide grass lined ditch to a 48 inch concrete culvert located approximately 20 feet east of the northwest property corner. The grass lined ditch area has been classified as a Class 4 steam. All work related to the Parkway Place project will occur outside the stream area. There is a concrete box inlet with a heavy steel trash rack at the 48 inch intake. From this point the storm water is conveyed in the 48 inch culvert approximately 145 feet to a 45 degree bend in the line. The bend directs the flow in a southeasterly direction toward a manhole located within the drive lane of the Parkway Place parking lot. An 11 foot wide concrete spillway has been constructed above the 48 inch culvert between the intake and 45 degree bend. The spillway directs the overflow to 2 -30 inch CMP culvert inlets located at the edge of parking, approximately 60 feet north of the northwest property line. The overflow lines convey the storm water easterly to Southcenter Boulevard and then northward in the street system. Therefore, once the inlet capacity of the 48 inch culvert is exceeded, the flow is routed to a separate storm system. Storm water flow in the 48 inch culvert is turned southward at the most northern manhole. John Howard, with the City of Tukwila, opened the manhole structure for my observation. The manhole has a round lid at the asphalt paving surface which covers•a locking lid on the pipe. It is my understanding that the locking lid is required because the 48 inch pipe flows under pressure during heavier rainfall events or when the river is at a higher elevation. At the time of my observation, there was approximately 6 inches of water flowing in the pipe. Stones with a diameter of approximately one foot were also observed at the bottom of the pipe. From the manhole the 48 inch pipe conveys the storm water approximately 850 south. The pipe is deflected 21 degrees to the west approximately 570 feet south of the manhole. Approximately 180 feet south of the bend, the pipe is deflected 64 degrees to the east. The 48 inch pipe then extends 90 feet where it connects to a 66 inch culvert. Connection to the 66 inch pipe is accomplished using a wye. The 66 inch culvert then conveys the storm water easterly to Southcenter Boulevard. The second off -site drainage course discharges from an arched culvert on the east side I -5 located near the southwest property corner. The discharge flows into a fenced pool area. The pool flows into a 54 inch culvert which conveys the storm water easterly. The culvert is located just south of the southwest property line. There is an asphalt maintenance road above the culvert between the Parkway Place parking lot and the pool area. The 54 inch pipe is connected to the 66 inch culvert which also conveys the storm water from the 48 inch pipe discussed above. It does not appear that any manholes exist along the 54 inch pipe between the pool and 66 inch pipe. 48" Storm Relocation: The existing 48 inch storm pipe will have to be abandon because the new buildings will be located over the line. The new line will be located approximately 30 west of the existing location. The only other gravity line on the west side of the project is a 12 inch sanitary sewer main. The sewer main will be relocated to the east side of the new building, and therefore will not present a problem. Since the new storm line will be located further west, the connection at the north end will be made at a higher elevation. The new pipe can therefore be installed with a greater slope than provided by the existing. This will increase the gravity flow capacity of the 48 inch pipe. The new line will be constructed so that access points do not exceed 400 feet. Details of the access point will have to be worked out with the city. It is anticipated that a bolt down lid, similar to the existing, will be provided. Relocation of the 48 inch pipe will not alter the basin characteristics. The new line will remain a conveyance system for off -site flows only. No catch basin for on -site drainage will be connected to the new line. Therefore drainage from the site will not enter the pipe during or after construction. The abandon section of 48 inch pipe will either be filled with control density backfill or dug up and crushed. Economics will determine which method of abandonment will used. This issue will be reviewed more closely during the preparation of construction documents. Sanitary Sewer System: The sanitary sewer main enters the site from the south near the southeast property corner. In the southern driveway, the sewer main is turned west and extends approximately 675 feet to a manhole located west of the asphalt parking lot. The sewer then angles northward to the loading dock area on the west side of the existing 9 story building. The manhole for the building connection is approximately 17 feet deep. There is an electronic flap gate on the building service line to prevent sewer from flowing into the building line. From this manhole the sewer main continues northward approximately 640 feet to a manhole located in the northwest corner of the site. This manhole also collects flows from areas north of the Parkway Place site. From the manhole in the northwest corner of the site, the flow is turned eastward toward Southcenter Boulevard. The sewer main crosses beneath Southcenter Boulevard and then turns northward. It appears the primary reason the sewer was extended to the west side of the Parkway site was to provide a future connection point for property to the west. Since the main was extended the longest possible route, it became relatively deep along the western side of the project. The existing 9 story building required a deep building sewer service to the basement and therefore the additional depth was justifiable. The new site plan locates a building over the existing sewer main. Therefore the sewer will have to be relocated. A deep sewer is not required since the new building will be slab on grade. This allows a greater flexibility in determining a new location for the sewer main. Finished grades on the east side of the site are 3 to 4 feet lower than on the west side. Locating the sewer main on the east side of the new building would take advantage of the lower finished grades. A sewer main located on the east side of the building would extend a shorter distance than the existing line. The shorter distance between existing flow line grades means the new section will have a greater slope than the existing pipe. Finished grade elevations will be significantly higher for any developments west of the Parkway Place project. Therefore a deep sewer connection depth is not required for the future areas. A new sewer stub can be extended to the west property line at a shallower depth. It appears the logical location for the new sewer main is on the east side of the new buildings. The existing sewer main will have to remain in operation during construction of the new main. This can be accomplished by setting a new manhole structure on the existing main at the lower connection point. The existing pipe will extend through the new to 1 structure and continue to convey the flow. From the manhole, new sewer pipe will be installed southward to the existing main. A new manhole will be set over the existing main at the higher connection point. Again the existing pipe will extend through the new manhole conveying the flow to the existing downstream pipes. The new sewer run will be tested and approved prior to routing the flows into them. Once approved, the existing pipe within the manhole will be removed and the manhole bottoms channeled to direct the flow into the new sewer pipe. Water Service: A dead end 10 inch water main currently serves the Parkway Place site. The dead end line also appears to be the only service for the adjacent properties on the north and south side of Parkway Place. The water main enters the site from Southcenter Boulevard, just north of the center driveway. The water main has a pressure of approximately 150 psi, and therefore fire flow is not in question. The water main will be looped around the new buildings. This is necessary to adequately provide the fire hydrant spacing. The existing dead end water main will have to be connected to another main so that the loop has two sources. This will allow sections of the main to be isolated for maintenance without shutting down the water supply for the entire system. A second feed will also be required by the fire marshal. The new connection could be made to the main in Southcenter Boulevard. It is my understanding that a water main has been extended to the west side of Southcenter Boulevard south of the Parkway Place project. This also maybe a location for a second connection. Viability of this connection will depend on the distance south and the willingness of the adjacent property owners to allow a water main extension across their property. The location of the second connection will be determined during the preparation of the construction documents. The connection to the Southcenter Boulevard main would require boring. Therefore we would like to pursue the connection to the main on the west side of the street first. Temporary Erosion Control and Grading: One of the first tasks will be the demolition of the existing building. It is my understanding that the building will be demolished using a crane and wrecking ball. This process will 8 require a relatively small area for stock piling the material and moving the construction equipment around the existing structure. During this phase, most of the existing asphalt paving will be retained. An area will dedicated for stock piling the material. The area will be enclosed with filter fabric fence to prevent silt laden storm water run -off from entering the existing storm system. Since the material will consist of crushed brick and concrete, siltation should not be a significant problem. A wetland exists in the southwest corner, just outside the parking lot area. The wetland has been delineated by a wetland specialist and located by a field survey crew. Since the existing parking lot drains from west to east, storm water run -off control should not be a problem during construction. The new site plan has been design so that new paving will not extend beyond the existing pavement in the vicinity of the wetland. A filter fabric fence should be installed prior to starting demolition so that the wetland can be clearly identified. The filter fabric fence will also prevent silt laden storm water from entering the wetland during construction. The next phase will be intensive grading for the preparation of building pads and construction of the retaining wall along the western side of the project. The retaining wall will be constructed from the top -down. Therefore the slope above the wall will not have to be cut back for construction. This will help minimize the disturbance to the slope above the wall. Material excavated from the slope during the retaining wall construction will be placed directly on the building pads and compacted in lifts. There is an existing ditch along the western edge of paving which conveys the hillside drainage to the north and south. The section which drains to the south flows into the wetland. Construction of the retaining wall and building pads will destroy the existing ditch. An interceptor swale will be constructed at the top of wall to convey the hillside drainage north and south. The interceptor swale will prevent storm water from flowing over the top of wall during construction and after the wall is completed. The section of swale draining southward will be tied back into the wetland, preserving the existing wetland hydrology. Filter fabric fence will be installed along the eastern limit of clearing. An interceptor swale will be constructed along the western side of filter fence. The swale will convey storm water run -off from the disturbed areas to sediment traps. This system should provide adequate protection for the downstream system. Crushed material from the existing building will be used to cap the building pads and graded parking areas. The crushed material will provide a surface which is resistant to erosion. 1 Other Best Management Practices will also be implemented to reduce the impacts to off -site areas. These include wetting the demolition materials being crushed and graded areas to reduce dust, installing filter fabric material in catch basin grates, sweeping parking lot and road surfaces, delineating limits of clearing on the plans and installation of a rock construction entrance. Site grade will be established to produce a balanced earthwork volume. This will help reduce truck traffic outside the project area during construction. These measures represent the minimum requirements which will be shown on the construction documents. Final Drainage System: The off -site drainage tightline system will retain the same function as the existing site. Relocation of the 48 inch pipe will not change the flow characteristics of the system. If the northern 48 inch pipe system inlet capacity is exceeded, then the storm water will follow the existing overflow route. The new building has been located so that the north face does not extend into the existing overflow route. If there is a failure of the overflow route, storm water will flow overland to the Southcenter Boulevard system. The building will not be flooded if this occurs. Buildings have also been located outside the overflow route for the southern 54 inch pipe system. If the inlet capacity of the 54 inch pipe is exceeded, or there is a failure, storm water will flow overland to the wetland area. This is the same route followed under the existing site plan. The building will not be flooded if this situation occurs. A swale will be constructed along the top of retaining wall at the western slope. From the retaining wall high point, the swale will convey storm water north and south along the top. At the point where the retaining wall is no longer required, the swales will be connected into the existing ditches. Therefore the existing drainage courses will be preserved. This is critical for the southern drainage course since it supplies water to the wetland. Drainage from the new parking lot will be collected by the existing catch basins. Underground pipe from the new catch basins at the loading docks will convey the storm water to the existing storm drainage system. The existing storm drainage system discharges untreated storm water directly into the Southcenter Boulevard system. Since this is no longer an acceptable practice, oil /water separation vaults with a coalescing chamber will be installed at the existing discharge points. This method of water quality improvement is widely accepted for existing storm system retrofit in urban areas. The water quality vaults will be sized for a 6 month -24 hour storm event according to Standards. Storm water flows greater event will be routed around the vault assures the oils and sediment trapped flushed to the downstream system. D.O.E. Storm Water Design than the 6 month -24 hour in a bypass system. This within the vault are not City of Tukwila John W. Rants, Mayor Department of Community Development Rick Beeler, Director MEMORANDUM TO: Diana Painter, DCD Associate Planner FROM: Gary Schulz, DCD Urban Environmentalist DATE: November 28, 1994 RE: Parkway Place Retail Center #L94 -0084 - Preliminary Environmental Review. I have reviewed the project site studies and planned proposals for this project. Also, I have visited much of the undeveloped portion of the site to provide recommendations for the SEPA file and BAR review. My comments focus on project compliance with the Sensitive Areas Ordinance (SAO, #1599) and the Interim Tree Ordinance ( #1715). This review includes 1) Sensitive areas study report, 2) Tree inventory & removal plan, 3) Landscape /tree replacement plan, 4) Geotechnical report, and 5) SEPA checklist. The following recommendations have been discussed with the Department of Community Development Director. SENSITIVE AREAS ORDINANCE/WETLAND ENHANCEMENT I. TMC Chapter 18.45.040 contains a provision to allow wetland buffer reduction when enhancement is appropriate and approved by the DCD Director. Because the on -site wetland buffer area has been altered and lacks significant native vegetation, the proposed reduction in buffer width is appropriate. However, the applicant must apply the SAO requirements for wetland alterations separately from other site development modifications that require tree replacement by the Tree Ordinance. The buffer enhancement plan is considered conceptual and will be reviewed under the guidelines of the SAO. Tree replacement for loss on other areas of the site cannot be transferred to the wetland buffer zone. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 Parkway Place Memo November 28, 1994 Page 2 U. Site reconnaissance found additional wetland area extending off -site but just north of the delineated wetland on the site. Although the additional wetland area is off -site, the 50 -foot buffer zone is on the project site. A field measurement indicated that the buffer zone could extend about 20 feet onto the project site. Since the on -site buffer is part of an old railroad bed, it could be considered for buffer reduction with enhancement. III. Wetland boundary and buffer need to be identified on all site maps. A 15 -foot building setback line should be shown to extend from the outer edge of the proposed wetland buffer area (TMC 18.45.040). IV. Following the standards of the SAO, the buffer enhancement plan will use native plants to incorporate diversity and function. TMC 18.45.040 (c)(3)(A)(ii) states The plan must include a variety of native vegetation that improves the functional attributes of the buffer and provides additional protection for the wetland or watercourse functions and values. The proposed enhancement only includes two species, willow and hawthorn. TREE ORDINANCE/PERMIT I. The applicant has submitted a tree replacement proposal based on Tree Ordinance Section 7.9 Exceptions. The Exception uses tree canopy cover guidelines for the project's overall tree retention and replacement. This replacement guideline is particularly appropriate because the area of trees to be removed is comprised of dense stands of trees. The dense composition of young trees would be costly to identify and map as "significant trees" on an individual basis. As discussed above, the tree canopy cover approach cannot utilize the wetland buffer area for replacement. However, it appears that most of the existing forested slope could be enhanced with native conifer tree species to add an evergreen component, and possibly provide long term slope stability. Two- to four -year old seedlings may be appropriate for forest enhancement plantings. The area where tree removal is to occur has at least four tree species. Sheet L1 Landscape/Tree Replacement Plan shows planting of only one species (bigleaf maple) in the Tree Replacement Area. The tree replacement plan should also incorporate more species diversity. Parkway Place Memo November 28, 1994 Page 3 II. As requested by Park Place Partners (Letter 10/31/94), tree removal was permitted on the site to accommodate the required geotechnical investigation. The written request was approved based on minimal tree disturbance including an 8 -foot wide cleared trail. The impacts appear to be greater than described and the area that was cleared for a trail ranges from 14 - 19 feet in width. In response to the City's concerns, a tree inventory for the permitted clearing was submitted by Park Place Partners (Letter 11/2/94). A total of fifty trees were inventoried and mapped as potential tree loss from the slope area. Tree removal and replacement for this disturbed area will be subject to the standards of the Tree Ordinance but not allowed the use of Section 7.9 Exceptions. Specifically, the disturbed area for geotechnical investigation will follow the tree replacement guidelines of Section 7.8 C. Detailed landscaping plans with specifications, planting notes, and performance measures ect. will be necessary for both wetland buffer enhancement and tree replacement. SEPA CONDITIONS I. If feasible, consider saving and relocating the higher quality trees from the existing landscape plantings. II. This is a new project with a large amount of impervious surface. Stormwater management plans should include detention and biofiltration using grass -lined swales and /or a water quality pond. If the entire site is to be re- developed, the standards of the King County Surface Water Design Manual should apply. cc: Rick Beeler, DCD Director m flJ SHANNON &WILSO CONSULTANTS January 5, 1995 City of. Tukwila Public Works Department 6300 Southcenter Boulevard Tukwila, Washington 98188 Attu: Mr. Ron Cameron, City Engineer RE: GEOTECBNICAL REVIEW, PROPOSED PARKWAY PLACE RETAIL CENTER Sr, Al TLE HANFORD . FAIRBANKS AND10RAra SAINT LC)UIS BOSTON 1494 This letter supplements our correspondence of November 28, 1994, and responds to geotechnical design recommendations contained in a December 21, 1994, memorandum from GeoEngineers addressed to Mr. Roy Bennion, regarding the design and construction of the soldier pile wall at the Parkway Place Retail Center in Tukwila. Many of the items discussed in the memorandum by GeoEngineers provide a satisfactory response to issues mentioned in our correspondence of November 28. Specifically, GeoEngineers has recommended a revised freeboard height of 3 feet to allow for greater accumulation of debris at the top of the wall. Similarly, GcoEngineers has revised the pressure diagram at the top of the wall to avoid discontinuities in the pressure distribution. Although not discussed in the December 21 memorandum, we understand that the wall design will also include a fence to meet requirements established by the city of Tukwila. However, there are still several issues which require resolution through either revising the design recommendations or providing clarification in the plans and specifications. These outstanding issues are briefly described below. WALL D $IGN Apparent Earth Pressures The GeoEngineers report of November 10, 1994, recommended a maximum earth pressure value of 60 H for the wall design where H represents the height of the wall (in feet) and the 400 NORTH 34TH STREET, SUITE 100 P,O. BOX300303 SEATTLE, WASHINGTON A8103 206.632.8020 FAX 206.633.6777 W- 6871 -01 City of Tukwila Attn: Mr. Ron Cameron ranuary 5, 1995 Page 2 SHANNON bWILSON, INC. pressure is expressed in units of pounds per square foot (psf). Shannon & Wilson's review letter of November 28, 1994, indicated that this was a conservative pressure for the wall design. GeoEngineers' memo of December 21, 1994, revised this maximum pressure to a value of 45 (11 +3), without providing any justification for the reduction in the wall pressure from the original value. of 60 Fi. Subsequently; we Learned from GeoEngineers that their original design pressure was based upon another project and had not been specifically tailored for this site. Upon further consideration they had decided to revise this earth pressure to be more in keeping with the actual conditions at the Parkway Place • Development. In our opinion, the revised pressure of 45 (13+3) is reasonable and consistent with the soil properties estimated for the hillside. Active_Earth Press: _um GeoEngineers' report of December 10, 1994, recommended active earth pressures corresponding to an equivalent fluid weight of 23 pcf to act on the portion of the soldier pile wall embedded below the base of the excavation. Shannon & Wilson's review letter of November 28, indicated that this equivalent fluid pressure was not consistent with other parameters provided for the wail design and should be reviewed. GeoEngineers' memo of December 21, 1994, clarified this issue by revising the active earth pressure to an equivalent fluid weight of 34 pcf and indicated that this pressure was derived considering that the groundwater table may be close to the ground surface at the base of the wall. • Under this assumption, we concur that the active earth pressures on the embedded portions of the soldier piles are reasonable for design. Resistance GeoEngineers' position for the design of passive resistance acting on the embedded portion of the soldier pile is that the passive resistance should commence at the base of the excavation and be computed corresponding to an equivalent fluid weight of 250 pcf which would act on an area equal to two and a half times the diameter of the soldier piles. Although a 48- inch - diameter storm sewer line will be constructed within 10 feet of the face of the wall, GeoEngineers contended in their correspondence of December 21, 1994, that construction of the sewer line in short segments and using a trench box would be adequate to provide this passive resistance to the permanent tieback wall. W-6871-01 City of Tukwila Attn: Mr. Ron Cameron January 5, 1995 Page 3 SHANNON EIWILSON. INC. The passive resistance issue is one of the major areas of disagreement that we have with GeoEngineers in the philosophy of the wall design. The basis of our disagreement is that we feel that the sewer line cannot be constructed to provide passive support to' the wall corresponding to the design assumptions. The basis for our position includes the following. First, while trench box construction is a common procedure used to install sewer lines, trench boxes are typically designed to resist active earth pressure and not the passive eartli pressures which axe assumed for design of the shoring wall. It is anticipated that any analysis of a trench box for passive earth pressures would indicate that the trench box is overstressed and would not support the applied load. Secondly, construction with a trench box typically involves partially back filling around the sewer pipe and then pulling the trench box to a new position while the remainder of the pipe is backfilled. This leaves a portion of the pipe unsupported while the remaining of the backfiill is placed. Under this condition, there is no passive resistance above the point where the backfill is stopped. Hence, this leads to discrepancy between the actual conditions and the design assumptions. The third factor is that even if a trench box could be completely baekfilled prior to pulling the trench box, there will exist a void space between the backdill and the adjacent soil as the trench box is advanced. This would ultimately result in some relaxation and lateral movement, hence violating the design assumption for the shoring wall. Therefore, in our opinion, the most appropriate design of the shoring wall is to assume that the lateral support to the wall is provided not by the base of the excavation at the parking lot level but by the base of the excavation for the sewer line. This effectively shifts the base of the excavation as much as 8 to 10 feet below the base of the parking lot. This would essentially require an additional row of tiebacks at about the level of the parking lot to provide adequate support for the wall to construct the storm sewer line. In our opinion, this is the most reasonable and appropriate design procedure that should be used for the wall design. Without accounting for this loss of lateral support for the excavation of the sewer 1 :ne, it is anticipated that the base of the shoring wall may become overstressed and displaced laterally towards the storm sewer line excavation. GeoEngineers' report of November 10, 1994, did not provide definitive recommendation for a permanent facing for the tieback wall. Although the report alluded to a possibility that concrete facing may be used on the wall, the report did not specifically recommend the use W- 6871 -01 City of Tukwila Attn: Mr. Ron Cameron January 5, 1995 Pagc4 SHANNON fsWILSON, INC. of a concrete facing material. GeoEngineers' memo of December 21, 1994, provided a position that treated timber lagging would be the permanent facing for the planned retaining wall, and that this facing would have a 50 -year warranted life. Furthermore, their memo of December 21, 1994, dismissed the use of shotcrete lagging on the basis that it may crack under tieback stressing and that it would be difficult to install drainage behind a shotcrete wall. The design recommendation for the lagging is another major area in which we disagree upon the design philosophy of the wall. While the buildings at the site may have a relatively short life span, as is evidenced by the life of the current structure, it is our opinion that the wall may be a permanent fixture at the site with a life of 50 years or longer. Under these conditions, we consider it imperative that it have a more permanent facing than treated timber lagging. In our opinion, shotcrete or preformed concrete panels are appropriate wall • facing material and should be used instead of treated timber lagging. Our concern for treated timber lagging is that there are no examples of permanent tieback walls with treated timber lagging that have performed satisfactorily for a span of 50 years. Whereas, there are numerous examples of 50 -year old concrete retaining walls that have provided satisfactory service. Although the issue of cracking of the concrete during stressing and potential deterioration of the reinforcing mesh was discussed by GeoEngineers, it is our opinion that if this is perceived to be a design issue that epoxy - coated reinforcing material may be used in the wall construction. Finally, numerous soil nail walls using shotcrete facing have been constructed using prefabricated drainage material behind the walla Hence, constructability is not a major issue to rule out the concrete Facing. for the wall design. In summary, we feel that use of the treated timber lagging is. an inappropriate design solution for a. long -term wall at this location and that a permanent wall facing using shotcrete or precast concrete panels is more appropriate considering the importance of the project. Miscellaneous Det is With the exception of the passive resistance at the base of the wall and the wall facing material, we believe that most of the major design issues for the wall have been addressed by GeoEngineers. However, there are still a number of details that will need to be reviewed on the design drawings and specifications to confirm the adequacy of the wall design. One of the details is drainage provisions behind the face of the wall. Specifically, while the GeoEngineers' memo of December 21, 1994, suggested full face coverage with a drainage W- 6871 -01 City of Tukwila Atm: Mr. Ron Cameron January 5, 1995 Page 5 SHANNON &WILSON. INC. material such as Miradiain 6000, it is not clear whether this refers to full face coverage over the entire length of the wall . or if it refers to full face coverage in zones of observed seepage. Such drainage details are quite important with the use of a permanent concrete wa11 facing. Therefore, these details would need to be worked out in the review of the design drawings. Similarly, we would need to review the design drawings to confirm the adequacy of the drainage at the base of the wail and confirm connection details with storm drain lines in the area. Please call if there are any questions on this letter. Sincerely, SHANNON & WILSON, INC. W. Paul Gant, P.E. Vice President WPG:EAS /dgw Enclosure: Important Information About Your Geotechnical Engineering Report cc: Robert Kimmcrling - WSDOT W6871- 01.1X21W6671- 1kd/dgd W- 6871 -01 AIM SHANNON & WILSON, INCConsultants Geotechnical and Environmental • w- 6871 -01 Attachment to Report Dated: January 5, 1995 To: City of Tukwila . Attn: Mr. Ron Cameron Page 1 of 2 Important Information About Your Geotechnical Engineering /. • Subsurface Waste Management (Remediation) Report GEOTECI3NYCAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS. Consalting geotechnical engineers prepare reports to meet the specific needs of Specific individuals A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant preps your report expressly for you and expressly for purposes you indicated. No one other than you should apply this report • for its intended purpose without feat conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without fast conferring with the geotecbnical engineer /geoscientist. AN ENGINEERING REPORT IS BASED ON PROJECT - SPECIFIC FACTORS A geotechnical engineering /subsurface waste management (remediation) report is based on a subsurface exploration plan designed to consider a unique set of project- specific factors. Dependix g on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope - of-service limitations imposed by the client To help avoid costly problems, have the consulting engineers) /scientist(s) evaluate how any factors which change subsequent to the date of the report, may affect the recommendations. Unless your consulting geotechnical/ civil engineer and/or scientist indicates otherwise, your report should not be used: 1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if refrigerated warehouse will be built instead of an uazafrigerated one or chemicals are discovered on or new the site); 2) when the son, elevation, or configuration of the proposed project is altered; 3) when the location or orientation of the proposed project is modified; 4) when there is a change of ownership; or 5) for application to an adjacent site. Geotechnical /civil engineers and/or scientists cannot accept responsibility for problems which may occur if they are not cotrsutted after factors which were considered in the development of the report have changed. SUBSURFACE CONDMONS CAN CHANGE. Subsurface conditions may be affected as a result of natural changes or human influence Because a geotechnicaVwaste management engineering report is based on conditions which existed at the time of subsurface exploration, construction decisions should not be based on an engineering report whose adequacy may have been affected by tuna Ask the geotecltnicallvtaste management consultant to advise if additional tests are desirable before construction strata. For ex ample, groundwater conditions coramonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods. earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/nastc management report: The geotechnicallcivil engineer and/or scientist should be kept apprised of any such events, and should be consulted to determine if additional tarn are necessary. MOST GEOTECRNICAL RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS. Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be fir more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your consultant can work together to help minimire their impact. Retaining your consultant to observe subsurface construction operations can be particu- larly beneficial in this respect. A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your geotechnical engineer's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Because actual Geo`j Engineers MEMORANDUM TO: FROM: DATE: Roy Bennion, Paul Grant/Shannon & Wilson and Kirk Lovelace/DEM Bert Pschunder, Jack Tuule December 21, 1994 FILE: 3944- 002 -R01 SUBJECT: Revised Soldier Pile Wall Design Parameters, Parkway Place Redmond This memorandum summarizes our recommendations for revised design parameters for the soldier pile and tieback wall to be constructed on the west side of the three - building complex for the proposed Parkway Place retail development in Tukwila, Washington. These recommendations are intended to supplement the recommendations given in our report of geotechnical engineering. services dated November 10, 1994, and have been discussed with Mr. Paul Grant of Shannon & Wilson, Inc. and Mr. Kirk Lovelace of DBM,, lnc. Our memorandum is intended in part to address comments provided. by Mr. Grant in a letter to the city of Tukwila dated November 28, 1994. The comments relate to a review of our November 10, 1994 report. FREEBOARD We originally recommended a freeboard of 2 feet between the top of the wall and the ground surface behind the wall to provide protection against soil and vegetative debris which might ravel down the slope. We agree that increasing the freeboard to at least 3 feet will provide better protection from ravelling debris and also more safety for individuals walking behind the wall. We understand frorn Mr. Lovelace that the incremental cost of providing 3 feet vs. 2 feet of freeboard is minor. The 3 feet of freeboard also reduces liability exposure for the owner resulting from injury or damage to _ people and vehicles below the wall if the debris were to overtop the wall. ACTIVE PRESSURES FOR WALL DESIGN For cantilever wall sections or where only one row of tiebacks is used, we recommend using a triangular soil pressure distribution based on an equivalent fluid pressure of 70 pcf (pounds per cubic foot). For sections of the wall where two or more rows of tiebacks will be used, we recommend that the lateral soil loads on the wall be determined using a triangular soil pressure distribution varying from 0 to (45) (H +3) down to a depth of 0.2H, where H is the distance from the ground surface behind the top of the wall to the base of the excavation. Below a depth of 0.2H and extending to the base of the excavation, a. uniform lateral soil pressure of (45) (H +3) should be used. These soil pressure values take into account the presence of accumulated debris at the top of the wall. MEMORANDUM to: December 21, 1994 Page 2 Roy Bennion, Paul Grant/Shannon & Wilson and Kirk Lovelace/DBM Lateral soil loads acting on the embedded portion of the soldier piles should be computed on the basis of a uniform pressure distribution of (34) (H +3) plus an equivalent fluid pressure of 34D, where D is the depth of the soldier pile embedment below the base of the excavation. These active pressure components should be applied to a width equal to the diameter of the soldier pile hole. These pressures are based on a simplified distribution which represents an average of two extreme ground water conditions: (1) ground water level at the base of the excavation, and (2) ground water level below the tip of the soldier piles. In actuality, the ground water level will likely be at about 8 feet below the planned depth of cut, or at about mid - height of the embedded portion of the soldier piles, assuming an embedment of 15 feet. LAGGING Properly treated and installed timber lagging will, in our opinion, provide a satisfactory • permanent facing for the planned retaining wall. With current treatment procedures we are advised that a 50 -year life warranty is provided. Careful field treatment of fresh cut faces in the lagging will be needed to maintain the warranted life of the lagging. ' Otherwise, the relative ease of installation and the better drainage provided through the lagging has distinct advantages over other, types of lagging such as shotcrete. Any system of lagging must be installed as the excavation proceeds downward. In 'the case of shotcrete, the installation procedure snakes it difficult to install and maintain a continuous drainage blanket between the soil and the concrete. In addition, tieback stressing is likely to result in cracking of the shotcrete which could have an adverse effect on the life span of the lagging if the mesh reinforcing becomes exposed to moisture infiltration through stressing - induced cracks. Therefore, with the assurances of longevity warranted by the lagging supplier, we recommend the use of timber lagging for the retaining wall. Lagging pressures should be taken as one -half of the active soil pressures provided above. PASSIVE RESISTANCE Passive resistance available on soldier piles extending below the level of excavation can be determined using an equivalent fluid pressure of 250 pounds per cubic foot applied to a width of 2.5 times the soldier pile hole diameter or the pile spacing, whichever is less. This equivalent fluid pressure also represents the average of the two ground water conditions described above, and includes a factor of safety of 1.5. We understand that the existing 48- inch- diameter storm sewer which crosses the three- building complex site will be relocated to an alignment with the centerline about 10 feet from the face of the wall. Construction of the new storm sewer would remove a significant amount of passive resistance available for the soldier piles if the entire trench (planned to be about 8 to 10 feet deep) is open at one time. We recommend that the sewer be constructed in segments such. that no more than 20 feet of trench is open at any one time. We recommend that bedding and bath -fill for the full trench section around and over the sewer pipe consist of clean sand and gravel compacted to at least 95 percent of MEMORANDUM to December 21, 1994 Page 3 Roy Bennion, Paul Grant/Shannon & Wilson and Kirk Lovelace /DBM t. `; • the maximum dry density determined in accordance with ASTM D -1557. The fill will likely need to be placed in thin (less than 6 inches loose thickness) lifts and lightweight, hand - operated equipment used to achieve proper compaction around the pipe. The open portion of trench should be fully supported with a trench box or other braced support system so that sufficient transfer of soil loads can take place across the trench.. Excavaxion for any future repairs of the storm sewer should also be limited to 20 -foot segments of trench. Bracing extending from the base of the exposed portion of the soldier piles across the trench and bearing against the future building could be used to help maintain the integrity of the soldier pile wall during such repairs. The capability of the building to withstand such lateral bracing loads should be checked by a structural engineer and could require some modification of the foundation design to accommodate such loading. WALL DRAINAGE Seepage from the face of the soil mass retained by the wall should be controlled by placing sheets of pre - fabricated composite drains such as Miradrain 6000 or equal over the entire exposed soil face as the wall is constructed. The sheets should be overlapped as necessary to provide a continuous flow path to the base of the wall. A drab consisting of a 6 -inch rigid wall PVC pipe should be placed at the base of the wall to collect water from the prefabricated drains The PVC pipes should extend to suitable disposal points. • o • Other, design parameters for tied -back soldier pile walls provided in our November 10, 1994 remain applicable. We trust that this information will be satisfactory for final design of the wall. PROJECT: DATE: PROPOSAL: LOCATION: APPLICANT: FILE NUMBER: CITY OF TUKWILA MITIGATED DETERMINATION OF NON - SIGNIFICANCE Parkway Place December 1, 1994 To demolish a 9 -story office building and construction 150,000 sq. ft. of retail space 17501 Southcenter Parkway Howard Turner, Architect, Turner & Associates Michael Sandorffy, Developer, Park Place Partners L94 -0085 SEPA THRESHOLD DETERMINATION: Mitigated Determination of Non - significance Issued December 1, 1994 ENVIRONMENTAL REVIEW RECORD The environmental review of this proposal consisted o an analysis based on the following documents included in the environmental record: A. SEPA Checklist, revised, dated November 10, 1994 B. Report from Arthur D. Little, "Environmental Baseline Assessment," April 29, 1993 C. Letter from Peter Jowise, Herrera Environmental Consultants, "Parkway Plaza Building Inspection," October 29, 1993 D. Report from Envirobusiness, Inc., "Phase II Limited Subsurface Investigation," November 12, 1993 E. Letter from Mark Jacobs, TP &E, "Parkway Place Boeing Site Trip Generation Study," September 15, 1994 F. Letter from Blayne Leingag, R.W. Rhine, "Parkway Plaza Building; Demolition," September 23, 1994 1 G. Letter from Michael Sandorffy, Parkway Place Partners, "Canopy Removal," October 31, 1994 H. Report from Talasaea Consultant, "Parkway Place Retail Center Sensitive Areas Ordinance Report," November 1994 I. Letter from Blayne Leingang, R.W. Rhine, "Parkway Place," November 7, 1994 J. Letter from Mark Jacobs, TP &E, "Parkway Place Boeing Site Midday Trip Generation," November 9, 1994 K. Letter from Shawn Parson, LandPlan, "Parkway Place," November 10, 1994 L. Report from GeoEngineers, "Report, Geotechnical Engineering Services, Proposed Parkway Place," November 10, 1994 M. Report from Bush, Roed & Hitchings, "Preliminary Report for BAR Review,: November 10, 1994 N. Letter from Michael Sandorffy, Parkway Place Partners, "Canopy Removal," November 10, 1994 O. Plans and Drawings by Howard Turner & Associates, November 10, 1994 P. Letter from Ron Cameron, City of Tukwila Public Works, "Parkway Place," November 18, 1994 Q. Letter from Paul Grant, Shannon & Wilson, "Geotechnical Review, Proposed Parkway Place Retail Center," November 28, 1994 R. Letter from Doug Johnson, Metro, "Transit Issues and the Parkway Place Retail Center," November 28, 1994 S. Letter from Gary Schulz, City of Tukwila Department of Community Development, "Parkway Place Retail Center Preliminary Environmental Review," November, 28, 1994 T. Conversation between Dale Morimoto, Environmental Program Manager, WSDOT, and Diana Painter, November 29, 1994 U. Conversation between Bob Kimmerling, Materials Laboratory, WSDOT, and Diana Painter, December 1, 1994 DESCRIPTION OF THE PROPOSAL Proposal: The applicant proposes demolishing a 216,000 square feet of office space and construction approximately 150,000 square feet of retail space. Existing site: A nine -story concrete slab and beam, brick -clad office building currently exists on the site. It is sited in the center of the 15 acre site, surrounded by parking and flanked on the northeast and southeast corners (originally part of this parcel) by two restaurants. A cooperative parking arrangement exists between the restaurants and the owner of this property. The west half of the site consists of a wooded hillside with two drainage ways, draining from west to east, and into the existing storm sewer system. Surrounding land use: Retail businesses and restaurants exist north of the site; a warehouse /retail outlet is located on the southern boundary; to the east is Southcenter 2 Parkway, which provides access to the site, with retail businesses across the street; and to the west is the right -of -way to Interstate 5. Project description: Demolition of the existing office building involves salvaging the brick and steel, and recycling other building materials by crushing them and using them for fill in what is now the basement of the existing office building. The next phase of the project involves excavating and constructing a 5' to 36' retaining wall at what is now the toe of the existing slope, on the west edge of an abandoned railroad bed. Soil from this excavation will also be used for fill on -site. The next phase involves re- location of utilities where applicable. The most significant re- location will be a 48" pressurized storm sewer line, which is located under the footprint of the proposed building. Two one -story concrete tilt -up structures will be constructed on the site, ranging in height from 26' to 48'. One approximately 32,000 square foot retail store will be located on the southern portion of the site. The larger structure, approximately 125,000 square feet, will house three retail outlets. The structures will be site from 220' to 375' west of the Southcenter Parkway, but will be oriented toward the Parkway. Some of the existing parking area and mature landscaping will be retained. Other portions of the parking lot will be re- striped, and new landscaping added. Oil water coalescing plates will be installed in the storm system for all parking areas. New landscaping will be added, and some re- forestation of the hillside will be undertaken. Access: Existing access to the site will be retained. The primary entry will be at the center of the eastern boundary, where there is a traffic signal. Secondary entries are located at the northeast and southeast corners of the site, and will also be retained. These will serve as truck and fire access for the new project, as well as access to the existing restaurants. An existing bus stop and bus shelter in the northeast corner of the site will remain. Sensitive areas: Classified sensitive areas on the site include Class 3 slopes from the railroad bed to the western boundary of the site; a Class II wetland at the south end of the property; and a Type 2 Watercourse near the north boundary of the property. A portion of the slope will be excavated in conjunction with this project and retained with a soldier pile retaining wall. Erosion controls and revegetation will be required in conjunction with construction. The wetland will be protected with a 25' vegetated buffer. The watercourse will not be affected by this project. PRINCIPAL CHECKLIST ITEMS Earth Mention excavation of hillside Discuss erosion control (says will do it during dry months, in January?) Air Discuss impacts of crushing operation, demolition 3 Surface water No surface water impacts. See below. Ground water Ground water on the site flows generally to the northwest. This would indicate that demolition and construction activities would have minimal impact to the classified watercourse in the northeast corner of the site. According to the SEPA Checklist, the closest construction activity to this watercourse is 70'. Vegetation Mention trees removed from landscaping, trees removed from hillside, tree replacement plan and vegetated wetland buffer Noise Mention noise during grading, construction, demolition, crushing Environmental health Mention asbestos in referenced in report Aesthetics Mention detailing of wall Transportation Problems with trip generation analysis No intersection impact analysis Transit stop /shelter to be retained Provide ped access Utilities Mention need for shoring up wall while utilities relocated. Mention coordination between storm sewer relocation and interference with WSDOT storm drainage line. MITIGATED CONDITIONS OF APPROVAL Issuance of a Mitigated Determination of Non - significance for this project is appropriate, as no probable significant adverse impacts on the environment can be foreseen as a result of this project. The following mitigation measures are required as a part of this project: 1. CODE REQUIREMENTS The following code requirements apply to this project, and are included here for information only. o Puget Sound Air Quality permit. o Mitigation measures during construction, including . . . . will be reviewed in conjunction with individual permits - and established. o Tree permit - 4 o LAO, SAO o Noise ordinance o Utilities, etc. .:: ! 01/05/85 11:08 FAX 206 633 6777 SHANNON & WILSON =Ali SHANNON F�WILSON, INC. Ianuary: 5, 19951 City of ZLkwila Public Works Department 6300 Southcenter Boulevard 'llikvvila, Washington 98188 Attn: Mr. Ron Cameron, City Engineer RE: CEOTECHNICAL REVIEW, PROPOSED PARKWAY PLACE RETAIL CENTER : S' xtt�1G.". L: rt14RR :3n3,1L- 1i`SiuAtRi.'Y.4t4'C'; S.:Y1dAf.YtalWi'tttt•:vn 002 Sr.AT fLE HANFORD FAIRBANKS ANCHORAGE SAINT LOUIS BOSTON 1464 This letter supplements our correspondence of November 28, 1994, and responds to geotechnical design recommendations contained in a December 21, 1994, memorandum from GeoEngineers addressed to Mr. Roy Bennion, regarding the design and construction of the soldier pile wall at the Parkway Place Retail Center in 'ltikwila. Many of the items discussed in the memorandum by GeoEngineeis provide a satisfactory response to issues mentioned in our correspondence of November 28. Specifically, GeoEngineers has recommended a revised freeboard height of 3 feet to allow for greater accumulation of debris at the top of the wall. Similarly, GeoEngineers has revised the pressure diagram at the top of the wall to avoid discontinuities in the pressure distribution. Although not discussed in the December 21 memorandum, we understand that the wall design will also include a fence to meet requirements established by the city of Tukwila. However, there are still several issues which require resolution through either revising the design recommendations or providing clarification in the plans and specifications. These outstanding issues are briefly described below. WAr,L DESIGN apparent Earth Pressut The GeoEngineers report of November 10, 1994, recommended a maximum earth pressure value of 60 H for the wall design where H represents the height of the wall (in feet) and the 40U NORTH 34TH STREET•SUITE 100 P.O. BOX 300303 SEATTLE. WASHINGTON A8103 206.632.8020 FAX 206'633.6777 W-6871-01 01/05/95 11:08 FAX 206 633 6777 City of Tukwila Attn: Mr. Ron Cameron January 5, 1995 Page 2 SHANNON & WILSON SHANNON %,AILSON, INC. pressure is =pressed in units of pounds per square foot (psf). Shannon & Wilson's review letter of November 28, 1994, indicated that this was a conservative pressure for the wall design. GeoEngineers' memo of December 21, 1994, revised this maximum pressure to a value of 45 (H +3), without providing any justification for the reduction in the wall pressure from the original value of 60 H. Subsequently, we learned from GeoEngineers that their original design pressure was based upon another project and had not been specifically tailored for this site. Upon further consideration they had decided to revise this earth pressure to be more in keeping with the actual conditions at the Parkway Place Development. In our opinion, the revised pressure of 45 (H +3) is reasonable and consistent with the soil properties estimated for the hillside. Active Earth Pressure GeoEngineers' report of December 10, 1994, recommended active earth pressures corresponding to an equivalent fluid weight of 23 pcf to act on the portion of the soldier pile wall embedded below the base of the excavation. Shannon & Wilson's review letter of November 28, indicated that this equivalent fluid pressure was not consistent with other parameters provided for the wall design and should be reviewed. GeoEngineers' memo of December 21, 1994, clarified this issue by revising the active earth pressure to an equivalent fluid weight of 34 pcf and indicated that this pressure was derived considering that the groundwater table may be close to the ground surface at the base of the wall. Under this assumption, we concur that the active earth pressures on the embedded portions of the soldier piles are reasonable for design. Passive Resistance GeoEngineers' position for the design of passive resistance acting on the embedded portion of the soldier pile is that the passive resistance should commence at the base of the excavation and be computed corresponding to an equivalent fluid weight of 250 pcf which would act on an area equal to two and a half times the diameter of the soldier piles. Although a 48 -inch- diameter storm sewer line will be constructed within 10 feet of the face of the wall, GeoEngineers contended in their correspondence of December 21, 1994, that construction of the sewer line in short segments and using a trench box would be adequate to provide this passive resistance to the permanent tieback wall. W-6871-01 x6003 01/05/95 11:09 FAX 206 633 6777 City of Tukwila Attn: Mr. Ron Cameron January 5, 1995 Page 3 SHANNON & WILSON f1 004 SHANNON WILSON. INC. The passive resistance issue is one of the major areas of disagreement that we have with GeoEngineers in the philosophy of the wall design. The basis of our disagreement is that we feel that the sewer line cannot be constructed to provide passive support to the wall corresponding to the design assumptions. The basis for our position includes the following. First, while trench box construction is a common procedure used to install sewer lines, trench boxes are typically designed to resist active earth pressure and not the passive earth pressures which are assumed for design of the shoring wall. It is anticipated that any analysis of a trench box for passive earth pressures would indicate that the trench box is overstressed and would not support the applied load. Secondly, construction with a trench box typically involves partially backfilling around the sewer pipe and then pulling the trench box to a new position while the remainder of the pipe is backfilled. This leaves a portion of . the pipe unsupported while the remaining of the backfill is placed. Under this condition, there is no passive resistance, above the point where the backfill is stopped: Hence, this leads to discrepancy between the actual conditions and the design assumptions. The third. factor is that even if a trench box could be completely baclffilled prior to pulling the trench box, there will exist a void space between the bacll and the adjacent soil as the trench box is advanced. This would ultimately result in some relaxation and lateral movement, hence violating the design - assumption for the shoring wall: Therefore, in our opinion, the most appropriate design of the shoring wall is to assume that the lateral support to the wall is provided not by the base of the excavation at the parking lot level but by the base of the excavation for the sewer line. This effectively shifts the base of the excavation as much as 8 to 10 feet below the base of the parking lot. This would essentially require an additional row of tiebacks at about the level of the parking lot to provide adequate support forwall to construct the storm sewer line. In our opinion, this is the most reasonable and appropriate design procedure that should be used for the wall design. Without accounting for this loss of lateral support for the excavation of the sewer ?:ne, it is anticipated that the base of the shoring wall may become overstressed and displaced laterally towards the storm sewer line excavation. GeoEngineers' report of November 10, 1994, did not provide definitive recommendation for a permanent facing for the tieback wall. Although the report alluded to a possibility that concrete facing may be used on the wall, the report did not specifically recommend the use W- 6871 -01 01/05/95 11:09 FAX 206 633 6777 City of Tukwila Attn: Mr. Ron Cameron January 5, 1995 Page 4 SHANNON & WILSON C. SHANNON WILSON. INC. of a concrete facing material. GeoEngineers' memo of December 21, 1994, provided a position that treated Limber lagging would be the permanent facing for the planned retaining wall, and that this facing would have a 50 -year warranted life. Furthermore, their memo of December 21, 1994, dismissed the use of shotcrete lagging on the basis that it may crack under tieback stressing and that it would be difficult to install drainage behind a shotcrete wall. The design recommendation for the lagging is another major area in which we disagree upon the design philosophy of the wall. While the buildings at the site may have a relatively short life span, as is evidenced by the life of the current structure, it is our opinion that the wall may be a permanent fixture at the site with a life of 50 years or longer. Under these conditions, we consider it imperative that it have a more permanent facing than treated timber lagging. In our opinion, shotcrete or preformed concrete panels are appropriate wall facing material and should be used instead of treated timber lagging. Our concern for treated timber lagging is that there are no examples of permanent tieback walls with treated timber lagging that have performed satisfactorily for a span of 50 years. Whereas, there are numerous examples of 50 -year old concrete retaining walls that have provided satisfactory service. Although the issue of cracking of the concrete during stressing and potential deterioration of the reinforcing mesh was discussed by GeoEngineers, it is our opinion that if this is perceived to be a design issue that epoxy - coated reinforcing material may be used in the wall construction. Finally, numerous soil nail walls using shotcrete facing have been constructed using prefabricated drainage material behind the wall. Hence, constructability is not a major issue to rule out the concrete facing. for the wall design. In summary, we feel that use of the treated timber lagging is. an inappropriate design solution for a long -term wall at this location and that a permanent wall facing using shotcrete or precast concrete.panels is more appropriate considering the importance of the project. Miscellaneous Details With the exception of the passive resistance at the base of the wall and the wall facing material, we believe that most of the major design issues for the wall have been addressed by GeoEngineers. However, there are still a number of details that will need to be reviewed on the design drawings and specifications to confirm the adequacy of the wall design. One of the details is drainage provisions behind the face of the wall. Specifically, while the GeoEngineers' memo of December 21, 1994, suggested full face coverage with a drainage W- 6871 -01 Ib 005 ... _ ................ .......... .. ..... _._..... .. _...... ... .... „.. A.,. ��..,......, w...,: ak.... c; e „rinn,Wav,.. >.�n «zrm:;r.ec. ... ,, ., SHANNON &WILSON, INC. material such as Miradrain 6000, it is not clear whether this refers to full face coverage over the entire length of the wall or if it refers to full face coverage in zones of observed seepage. Such drainage details are quite important with the use of a permanent concrete wall facing. Therefore, these details would need to be worked out in the review of the design drawings. Similarly, we would need to review the design drawings to confirm the adequacy of the drainage at the base of the wall and confirm connection details with storm drain lines in the area. Please call if there are any questions on this letter. Sincerely, SHANNON & WILSON, INC W. Paul Grant, RE. Vice President WPG:EAS /dgw Enclosure: Important Information About Your Geotechnical Engineering Report cc: Robert Kimnierling - WSDOT W6871 -0I .L'r2/W6871- Ikd/dgw 01/05/95 11:10 FAX 206 633 6777 AIM S WItSOIt, I. Geotechnicst HANNON and &n Environmental INC. SHANNON & WILSON W- 687,1 -01 Abutment toLort pad: January 5, 1995 'g,: City of Tukwila . Attn: Mr. Ron Cameron Important Information About Your Geotecbnical Engineering/. Subsurface Waste Management (Remediation) Report GEOTECEIrl1CAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS. X007 Page 1 of 2 Consulting geotechnical engineers prepare reports to meet the specific needs of /pacific individuals A report prepared for civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant prepared your report etpreasly for you and expressly for purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the geoteclmicat engineerrgeoscientiat. AN ENGINEERING REPORT IS BASED ON PROJECT-SPECII<ZC FACTORS A geotechnical engineering /subsurface waste management (mediation) report is based on a subsurface exploration plan designed to consider a unique set of project- specific factors. Depending on the project, these may include: the genes) nature of the structure and property involved; its sins and configuration; its historical use and practice; the location of the structure on the silo and ib orientation; other improvements such u access roads, parking lots, and underground utilities; and the additional risk created by scope - of- service limiaations imposed by the client. To help avoid wetly problems, have the eonsultirg engineer(s)/scientist(s) evaluate bow any factors which change aubsequent to the date of the report, may affect the recommendations Unless your consulting geotechnical/ civil engineer and/or scientist indicates otherwise, your report should not be used: 1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the sit); 2) when the sins, elevation. or configuration of the Proposed project is altered: 3) when the location or orientation of the proposed project is modified; 4) when there is a change of ewvnenrhip; or 5) for application to an adjacent site. Geotchnical/civil engineers and/or scientist; cannot accept responsibility for problems which may occur if they are not consulted after factors which sere considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be effected as a result of natural changes or human influence. Because a geotechnical/waste management engineering report is based an conditions which existed at the time of subsurface exploration, construction decisions should not be based on an engineering report whose adequacy may have been affected by tines Ask the geoteclrnieal /vtaste management consultmt to advise if additional tests are desirable before construction starts. For example; groundwnitter conditions commonly vary seasonally. Construction operations at or adjacent to the sits and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnicaUwteste management report: The geotechnicaUcivil engineer and/or scientist should be kept apprised of any such events, and should be consulted to determine if additional tests are necessary. MOST GEOTEcRNICAL RECOMMENDATIONS ARE PROFESSIONAL JUDGMENT'S. Site exploration and testing identifies actual surface and subsurface conditions only at those points when samples are taken. The data were extrapolated by your consultant who then applied judgment to render an opinion about overall subsurface condition& The actual interface between materials nwry be far more gradual or abrupt than your report indicate. Actual conditions in area not sampled may differ from those predicted in your report. While nothing can be done to prevent. such situations, you and your consoling can work together to help mioirnhe their impact. Retaining your consultant m observe subsurface construction operations can be particu- larly beneficial in this respect. A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your geotechnical engineer's report are preliminuy becauae they must be based on the assumption that conditions revealed through selecthe exploratory sampling are indicative of actual conditions throughout a site. Because actual 01/05/25 11:11 FAX 206 633 6777 SHANNON & WILSON Geo -"Engineers MEMORANDUM cioos Redmond TO: Roy Bennion, Paul Grant/Shannon & Wilson and Kirk LovelaceJDBM FROM: Bert Pschunder, Jack Tuttle DATE: December 21, 1994 FILE: 3944-002 -RO1 SUBJECT: Revised Soldier Pile Wall Design Parameters, Parkway Place This memorandum summarizes our recommendations for revised design parameters for the soldier pile and tieback wall to be constructed on the west side of the three- building complex for the proposed Parkway Place retail development in Tukwila, Washington. These recommendations are intended to supplement the recommendations given in our report of geotechnical engineering services dated November 10. 1994, and have been discussed with Mr. Paul Grant of Shannon & Wilson, Inc. and Mr. Kirk Lovelace of DBM, inc. Our memoranduul is intended in part to address comments provided. by Mr. Grant in a letter to the city of Tukwila dated November 28, 1994. The comments relate to a review of our November 10, 1994 report. FREEBOARD We originally recommended a freeboard of 2 feet between the top of the wall and the ground surface behind the wall to provide protection against soil and vegetative debris which might ravel down the slope. We agree that increasing the freeboard to at least 3 feet will provide better protection from ravelling debris and also more safety for individuals walking behind the wall. We understand from Mr. Lovelace that the incremental cost of providing 3 feet vs. 2 feet of freeboard is minor. The 3 feet of freeboard also reduces liability exposure for the owner resulting from injury or damage to people and vehicles below the wall if the debris were to overtop the wall. ACTIVE PRESSURES FOR WALL DESIGN For cantilever wall sections or where only one row of tiebacks is used, we recommend using a triangular soil pressure distribution based on an equivalent fluid pressure of 70 pcf (pounds per cubic foot). For sections of the wall where two or more rows of tiebacks will be used, we recommend that the lateral soil loads on the wall be determined using a triangular soil pressure distribution varying t/ from 0 to (45) (H +3) down to a depth of 0.211, where H is the distance from the ground surface behind the top of the wall to the base of the excavation. Below a depth of 0.2H and extending to the base of the excavation, a uniform lateral soil pressure of (45) (H +3) should be used. These soil pressure values take into account the presence of accumulated debris at the top of the wall. 01/05/96 11:12 FAX 206 633 6777 MEMORANDUM to: December 21, 1994 Page 2 SHANNON & WILSON Roy Bennion, Paul Grant/Shannon & Wilson and Kirk Lovelace/DBM -Q 0 09 . . Lateral soil loads acting on the embedded portion of the soldier piles should be computed on the basis of a uniform pressure distribution of (34) (H +3) plus an equivalent fluid pressure of 34D, where D is the depth of the soldier pile embedment below the base of the excavation. These active pressure components should be applied to a width equal to the diameter of the soldier pile hole. These pressures are based on a simplified distribution which represents an average of two extreme ground water conditions: (1) ground water level at the base of the excavation, and (2) ground water level below the tip of the soldier piles. In actuality, the ground water level will likely be at about 8 feet below the planned depth of cut, or at about mid - height of the embedded portion of the soldier piles, assuming an embedment of 15 feet. LAGGING Properly treated and installed timber lagging will, in our opinion, provide a satisfactory permanent facing for the planned retaining wall. With current treatment procedures we are advised that a 50 -year life warranty is provided. Careful field treatment of fresh cut faces in the lagging will be needed to maintain the warranted life of the lagging. Otherwise, the relative ease of installation and the better drainage provided through the lagging has distinct advantages over other types of lagging such as shotcrete. Any system of lagging must be installed as the excavation proceeds downward. In'the case of shotcrete, the installation procedure makes it difficult to install and maintain a continuous drainage blanket between the soil and the concrete. In addition, tieback stressing is likely to result in cracking of the shotcrete which could have an adverse effect on the life span of the lagging if the mesh reinforcing becomes exposed to moisture infiltration through stressing - induced cracks. Therefore, with the assurances of longevity warranted by the lagging supplier, we recommend the use of timber lagging for the retaining wail. Lagging pressures should be taken as one -half of the active soil pressures provided above. PASSIVE RESISTANCE Passive resistance available on soldier piles extending below the level of excavation can be determined using an equivalent fluid pressure of 250 pounds per cubic foot applied to a width of 2.5 times the soldier pile hole diameter or the pile spacing, whichever is less. This equivalent fluid pressure also represents the average of the two ground water conditions described above, and includes a factor of safety of 1.5. We understand that the existing 48- inciu- diameter storm sewer which crosses the three- building complex site will be relocated to an alignment with the centerline about 10 feet from the face of the wall. Construction of the new storm sewer would remove a significant amount of passive resistance available for the soldier piles if the entire trench (planned to be about 8 to 10 feet deep) is open at one time. We recommend that the sewer be constructed in segments such that no more than 20 feet of trench is open at any one time. We recommend that bedding and backfill for the full trench section around and over the sewer pipe consist of clean sand and gravel compacted to at least 95 percent of 01/05/95 • 11:12 FAX. 206 633 6777 MEMORANDUM to: December 21, 1994 Page 3 SHANNON & WILSON �.w,Ij 010 Roy Bennion, Paul Grant/Shannon & Wilson and Kirk Lovelace/DBM the maximum dry density determined in accordance with ASTM D -1557. The fill will likely need to be placed in thin (less than 6 inches loose thickness) lifts and lightweight, hand - operated equipment used to achieve proper compaction around the pipe. The open portion of trench should be fully supported with a trench box or other braced support system so that sufficient transfer of soil loads can take place across the trench. Excavation for any future repairs of the storm sewer should also be limited to 20 -foot segments of trench. Bracing extending from the base of the exposed portion of the soldier piles across the trench and bearing against the future building could be used to help maintain the integrity of the soldier pile wall during such repairs. The capability of the building to withstand such lateral bracing loads should be checked by a structural engineer and could require some modification of the foundation design to accommodate such loading. WALL DRAINAGE Seepage from the face of the soil mass retained by the wall should be controlled by placing sheets of pre - fabricated composite drains such as Miradrain 6000 or equal over the entire exposed soil face as the wall is constructed. The sheets should be overlapped as necessary to provide a continuous flow path to the base of the wall. A drain consisting of a 6 -inch rigid wall PVC pipe should be placed at the base of the wall to collect water from the prefabricated drains The PVC pipes should extend to suitable disposal points. .o. Other, design parameters for tied -back soldier pile walls provided in our November 10, 1994 remain applicable. We trust that this information will be satisfactory for final design of the wall. i2 /01 /04 15:57 FAX 206 633 6777 SHANNON & WILSON agall SHANNON WILSON, INC. � � ' GEOTECHNICAL AND ENVIRONMENTAL CONSULTANTS November <28, 1994 City of Tukwila Public Works Depaitment 6300 Southcenter Boulevard Zlrkwila, Washington 98188 Attn: Mr. Ron Cameron, City Engineer 1 1001 SEATTLE HANFORD FAIRBANKS ANCHORAGE SAINT LOUIS BOSTON 144 RE: GEOTECHNICAL REVIEW, PROPOSED PARKWAY PLACE RETAIL CENTER This letter provides comments based upon our review of the November 10, 1994, geotechnical report by GeoEngineers for the proposed Parkway Place retail center. The proposed development includes constructing a 30- to 35-foot-high soldier pile and tieback wall at the toe of a steep hillside. The purpose of this wall is to allow excavation of the soils at the toe of the hillside for the project development. Our review was conducted at your request because this hillside slope falls within the City of Thkwila's Class 3 landslide potential hazard area. The purpose of our review was to comment on the stability of the hillside and the design parameters for the soldier pile and tieback wall in context with requirements of the City's Sensitive Area Ordinance. Our review does not address aspects of the City's Sensitive Area Ordinance pertaining to wetlands, streams, or forested areas. Detailed comments on our review of the proposed project are provided below. However, we generally concur that the soldier pile and tieback wall may be constructed without decreasing the stability of the hillside. Furthermore, we agree that there is no evidence of prior major instability of the existing hillside slope in the vicinity of the project. The comments provided below address the details of the wall design and items that would need to be addressed in the project plans and specifications for the wall construction. HILLSIDE STABILI'T'Y The hillside adjacent to the project falls within the City of 'Tukwila's Class 3 potential landslide hazard area. This designation corresponds to slopes generally between 15 and 40 400 NORTH 34TH STREET. SUITE 100 P.O. BOX 300303 SEATTLE, WASHINGTON 98103 206632.8020 FAX 2080 E33 4 87 7 7 W- 6871 -01 12/01/94 15:57 FAX 208 633 6777 SHANNON & WILSON City of Tukwila Attn: Mr. Ron Cameron November 28, 1994 Page 2 SHANNON &WILSON. INC. percent, and some greater than 40 percent, that are underlain by impermeable soils. We understand that the existing hillside slope was graded to its present configuration of a slope of 1 3 /4(H):1(V) in the mid- 1960s. The geotechnical report for the project and existing geologic maps do not indicate any instability in the portion of the hillside that will be affected byrthe project development. GeoEngineers analyzed the stability of the slope on the assumption that the existing slope configuration has a static factor -of- safety (FS) of 1.25. This assumption was based upon earlier extensive stability analyses of the hillside that were conducted by Dames & Moore in the mid- 1960s. With this assumed FS for the existing conditions, GeoEngineers then derived soil properties including a friction angle of 37 degrees and a cohesion value of 25 pounds per square foot (psf) that would be consistent with this 1.25 stability FS. GeoEngineers then evaluated the stability of the completed soldier pile and tieback retaining system: They determined a static FS of 1.8 and a dynamic FS of 1.2 corresponding to a seismic coefficient of 0.20g. In our opinion, the stability analyses that were conducted provide a reasonable and conservative evaluation of the stability of the hillside slope. The soil parameters selected for analyses are conservative with respect to the results of the laboratory tests conducted by GeoEngineers on soil specimens retrieved from the site. In our opinion, the soil parameters are also conservative considering Shannon & Wilson's experience in testing strength properties of•glacial sediments. Therefore, it is concluded that the computed FS are reasonable and conservative for the project and that construction of the retaining wall would not decrease the stability of the existing hillside slope. However, a number of elements regarding the design and construction of the wall will need to be addressed, as discussed below. WALL DESIGN In general, it is our opinion that a soldier pile and tieback wall may provide adequate restraint to the toe of the hillside for the proposed project. However, a number of details need to be further developed and reflected on the plans and specifications for the wall W- 6871 -01 j002 1.2/01/94 15:58 FAX 206 633 6777 • City of Tukwila Attn: Mr. Roa Cameron November 28, 1994 Page 3 SHANNON & WILSON fm 003 SHANNON iWILSON, INC construction. Comments on the design parameters and our expectations for details that need to be reflected on the plans and specifications are indicated below. Freeboard The geotechnical report for the project recommends that the soldier pile wall be constructed with a minimum freeboard of 2 feet. This freeboard reflects the distance between the top of the wall and the ground surface of' the retained soil below the top of the wall. In our opinion, a 3 -foot minimum freeboard would provide better protection from debris as well as for personal safety of any individuals walking behind the wall. Fence Since the access to the top of the wall would appear to be unconstrained, it is suggested that a chain link fence be ccnstructed at the top of the wall as a safety measure. 70 Pouncs Per Cubic Foot fl Equivalent Fluid We ght The design report recommends using an equivalent fluid weight of 70 pcf for the design of the top 10 feet of the wall. We concur with this recommendation as restricted to the cantilever section of the wall or the section of the wall which may only have one row of tiebacks. Where wall sections may have two or more rows of tiebacks, use of the 70 pcf equivalent fluid weight would lead to a discontinuity with the rectangular wall pressure of 60H. This discontinuity may be avoided by using a truncated pressure distribution for wall segments having two or more rows of tiebacks where the full wall pressure (60H) is achieved at a distance of 0.2H below the top of the wall. It is recommended that GeoEngineers review this condition and revise their recommendations as appropriate. 60H Wall Pressure The 60H uniform pressure distribution on thc tieback section of the shoring wall, in our opinion, is a reasonable and conservative pressure distribution for the wall design. W-6871-01 12/01/94 15:58 FAX 206 633 6777 SHANNON & WILSON ` . City of Tukwila Attn: Mr. Ron Cameron November 28, 1994 Page 4 SHANNON F,WILSON, INC However, it is suggested that GeoEngineers consider that the H factor for determining the pressure include not_only the heig fiheeut But arsL,, . 23 pd' Equivalent Fluid Weight The geotechnical report contains a recommendation for an active earth pressure corresponding to an equivalent fluid weight of 23 pcf to act on the soldier piles below the base of the excavation. In our opinion, this value of equivalent fluid pressure is inconsistent with the 70•pcf recommended for the top section of the wall. In our opinion, the equivalent fiuid weight of 23 pcf is unconservative and this value should be revised to be an equivalent fluid weight that is consistent with the design of the cantilever section of the shoring wall. %ageng The geotechnical report recommends use of wood lagging to retain the soil at the face of the excavation. While not necessary for the geotechnical report, the plans and specifications for the wall will need to indicate the size of the wood lagging and details for filling voids behind the lagging. Also, since this will be a permanent retaining wall, it is strongly suggested that the wood lagging be pressure - treated and that sawcut ends of the lagging be treated with wood preservative. In our opinion, cast-in-place concrete lagging would provide more positive support for the wall compared to wood lagging since wood lagging may be subject to deterioration over a long period of time. Therefore, it is suggested that the design also consider cast-in-place lagging (shotcrete) as a potential substitute for wood lagging. Wall Facing Pressure The geotechnical report does not contain any recommendations for lateral earth pressures acting upon the lagging or the permanent wall facing material. These parameters will need to be addressed in the plans and specifications for the retaining wall. W-6871-01 12/01/94 15:59 FAX 206 633 6777 SHANNON & WILSON Q005 City of Tukwila Attn: Mr. Ron Cameron November 28, 1994 Page 5 Passive istance SHANNON &WILSON, INC. While we generally concur with the passive pressure recommendations provided at the toe of the soldier pile and tieback wall, these pressures may be severely affected by the construction of the new 48- inch - diameter storm sewer which may be constructed at a distance of about 10 feet from the face of the wall. In our opinion, the pressures provided in the geotechnical report did not reflect the potential construction conditions of this storm sewer. It is suggested that these pressures be reduced to account for the storm sewer construction or that the passive resistance be neglected over the anticipated depth of the storm sewer construction. Neglecting the passive pressures over this portion would represent a conservative design approach and would allow for removal or repair of the storm sewer at some point in the future without seriously jeopardizing the stability of the adjacent wall. Double - Corrosion Protection, The geotechnical report recommends double- corrosion protection for all tiebacks within the retaining wall. The design documents will need to reflect appropriate details, for protecting the heads of these anchors from corrosion. SAGE The geotechnical report does not contain details for controlling seepage at the face of the wall. The plans and specifications for the wall construction will need to address the type of drainage material to be installed at the face of the wall, the width cf the material, spacing of the material, the location of any drains at the toe of the wall, and the connection of these drains to any nearby storm sewers. W-6871-01 12/01/94 15:59 FAX 206 633 6777 SHANNON & WILSON City of Tukwila Attn: Mr. Ron Cameron November 28, 1994 Page 6 WALL FACING Zoos SHANNON 6WILSON. INC The geotechnica1 report alludes to the possibility that a concrete facing may be used at the face of the wall. We concur that a concrete facing is an appropriate long -term solution for the construction of the wall and that the final configuration of the wall include a permanent concrete facing. .Considering that various options are available for the architectural finish of the concrete facing, the City of Tukwila should review the details for this wall facing to assure that they are consistent with the intent of the Sensitive Area Ordinance and any other design /aesthetics requirements of the City. CONSTRUCTION MONITORING The geotechnical report recommends that GeoEngineers be involved in construction monitoring of the soldier pile and tieback wall. We concur that this service will be required to confirm the safety and adequacy of the design parameters recommended for the wall. Additionally, it is recommended that Shannon & Wilson review design memos and periodically review the construction of the wall on behalf of the City. COVENANTS It is suggested that the City place a covenant upon the property indicating that the permanent tieback wall on the property is an integral factor in maintaining the stability of the adjacent hillside. The safety of the hill Side will be dependent upon proper maintenance of the wall, which would include maintaining drainage behind the wall and the integrity of the drains that may be installed at the toe of the 'wall. Any deterioration (cracking or movement) of the wall would need to be addressed by future owners. Also, the maintenance of the waJ1 would require the periodic inspection of the top of the wall to confirm that there is no accumulation of debris at the top of the wall that may jeopardize the stability of the wall or may potentially overtop the wall. W- 6871 -01 12/01/94 16:00 FAX 206 633 6777 City of Tukwila Attn: Mr. Ron Cameron November 28, 1994 Page? SHANNON & WILSON Please call if there are any questions on this letter. Sincerely, SHANNON & WILSON, INC. GA ' ∎: W. Paul Giant, P.E. Vice President WPG :EAS/lkd SHANNON ,WILSON. INC. �uas 1? 4� Enclosure: Important Information About Your Geotechnical Engineering Report W6E71 -01.LTii1W6171 -ikd/1 qh 007 12/01/94 16:00 FAX 206 633 6777 41111111 MINN Geotechnical SHANNON & WILSON, INC. Geotechnical and Environmental Consultants SHANNON & WILSON W- 6871 -01 Attachment to Report paned: November 28, 1994 Q 008 gags 1 of 2 7b: City of Tukwila Attn: Mr. Ron Cameron Important Information About Your Geotechnical Engineering/ Subsurface Waste Management (Remediation) Report GEOTEcR IICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS. Consulting geotechnical engineer:; prepare reports to meet the specific needs of specific individuals A report prepared for a civil engineer racy not be adequate for a construction contractor or even another civil engineer. ITnless indicaed otherwise, your consultant preps your report expressly for you and expressly for purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the geotechnical engineer/geoscientist. AN ENGINEERING REPORT IS BASED ON PROJECT - SPECIFIC FACTORS. A geotechnical engineering /subsurface waste management (remediation) report is based on a subsurface exploration plan designed to consider a unique set of project - specific factors. Depending on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as asses roads, parking lots, and underground utilities; and the additional risk created by scope - of- service limitations imposed by the client. To help avoid costly problems, have the consulting engineer(s)/scientist(s) evaluate how any factors which change subsequent to the date of the report, may affect the recommendations 'Unless your consulting geotechnical/ civil engineer and /or scientist indicates otherwise, your report should not be used: 1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an uarehigerated one, or chemicals are discovered on or near the site); 2) when the sire, elevation, or configuration of the proposed project is altered; 3) when the Location or orientation of the proposed project is modified; 4) when there is a change of ownership; or 5) for application to an adjacent site. Geotechnical/civil engineers and/or scientists cannot accept responsibility for problems which may occur if they are not consulted after factors which were considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be affected as a result of natural changes or human influence. Because a geotechnical/waste management engineering report is based on conditions which existed at the tinge of subsurface exploration, construction decisions should not be based on an engineering report whose adequacy may have been affected by time. Ask the geotechnical/waste management consultant to advise if additional tests ars desirable before construction starts For example, groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/esite management report. The zootechnical/civil engineer and/or scientist should be kept apprised of any such events, and should be consulted to determine if additional teats am necessary. MOST GEOTECSNICAL RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS. Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant who then applied judgment to reader an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates,. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situation; you and your consultant can walk together to help minimize their impact. Retaining your cansultant to observe subsurface construction operations can be particu- larly beneficial in this respect. A REPORT'S CONCLUSIONS ARE PRELI VNARY The conclusions contained in your geotechnical engineer's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicahe of actual conditions throughout a site. Because actual RE '^ IVED JAN 1 11999 QQIVUV►u►v► ► Y DEVELOPMENT & storm line Geo Engineers have proposed a wood wall and passive resistance that has been reviewed by Paul Grant of Shannon and Wilson. It is recommended to require a concrete wall: 1. as recommended by Shannon and Wilson 2. this wall is permanent, has the freeway above, there is no foreseeable additional development to change the wall so changes or maintenance that would eventually required of a wood wall should be avoided, 3. any work would /could affect the public 48 inch drain; the construction of the building has extraordinary requirements to work around this drain and all efforts must be made to avoid any future disturbances of the line, 4. WSDOT review and comments are expected to recommend requirement of a concrete wall which is their standard, 5. any wall maintenance will affect or preclude truck access to the building. Therefore, the wall needs to be concrete as recommended by Shannon and Wilson instead of the treated timber lagging. The wall design needs to provide for the passive resistance explained on page 3 and 4 of the Shannon and Wilson report. WSDOT review and comment should be obtained from Robert Kimmerling. City of Tukwila. Department of Community Development To: Ron Cameron From: Diana Painter Subject: Trip Generation Studies - Parkway Place Date: MEMO November 30, 1994.. John W. Rants, Mayor • Rick Beeler, Director I have asked for clarification on the two trip generation studies for Parkway Place on several occasions, and.1iave responses from you indicating that the studies are adequate. On further review of there-studies, I am not convinced that they adequately reflect forecasted conditions for this project. ' Therefore, I am questioning your memo of November 18, 1994 that states that the TP &E traffic studies identify that the redevelopment generates less peak traffic [than the existing office building]. The SEPA determination for this project must be made .at noon on December 1, 1994 if the project is to go ahead. At this point in time I am not satisfied that the traffic impacts of this project have been adequately assessed. Please get back to me or-Rick the morning of the 1st if you disagree with this decision. I question the following assumptions and results of the TP &E study; 1. The September 150.994 letter from TP &E states that, 'because of pass -by traffic and. diverted link trips for retail uses along Southcenter Boulevard, the actual new trips associated with the proposed Parkway Place project will be relatively small' (p. 3). According to Dave Enger, however, only 40% of trips in a retail area such as this can be attributed to pass -by traffic. Based on this rule- of-thumb, I am not satisfied that 'all the traffic is already there.' 2. The September 15th letter from TP &E states that, "Our field observations showed substantial inter - connectivity between the development along Southcenter Parkway. The intersite connections reduce the need to use Southcenter Parkway when traveling between retail sites" (p. 2). As you know, Southcenter. Parkway is the only street in this vicinity. And there is no physical 'interconnectivity' between sites on the saine side of the street as this project. Formal 'landscaping, grade changes .and other physical barriers prevent traveling. from site to site by car west of Southcenter Parkway. Let me know if I am mis- interpreting this assumption, but I don't believe 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 4313665 it accurately reflects site conditions. 3: The same letter suggests that approach channelization improvements in the main driveway to the site may help with traffic movement. As you can tell from the drawings for the project, no improvements are planned, and none were indicated as necessary in your memo of November 18th. I would like to be certain that your intention is to NOT require any improvements to the driveway before finalizing the SEPA conditions for this project. The conclusions of the September 15th trip generation study indicated that fewer trips are generated by the retail project than the office project. Average Weekday trips, a.m. trips and p.m. trips were forecasted. I requested that the consultant do another analysis that compared noon•hour trips between the two uses, since you have always said that noon is our peak hour in the Southcenter area. In a letter dated November 9th, the consultant distributed the forecasted daily trips for the shopping center across the day, using percentages supplied by . the fi'E Trip Generation manual. [Incidently, the two distributions shown were for shopping centers under 100,000 sq. ft. in size, and over 300,000 sq. ft. in size. This project is 150,000 sq. ft.]. Averaging the percentage entering and the percentage existing for various hours in the day, the consultant supplied figures that showed that the 12 -1 noon hour peak and the 5 -6 p.m. peak were the highest, and were about the same on a national level. I would like to know how this compares with your knowledge of the Southcenter area. I am not convinced that this distribution is appropriate here. I can understand that we would want to substantiate our decisions on peak hour figures for the area. But the consultant goes on to say that "we believe that a sizeable number of the office employees choose to eat out or run noon time errands, thus generating significant traffic volumes." This does not sound well- documented, and conflicts with the previous statements that the sites are connected so there's no need to use the street, and that the traffic is already in the area. It also contradicts actual conditions. This is the primary restaurant strip in the-Southcenter area and at least five shopping malls are within walking distance of the office building. The study does not compare peak hour trips for retail and office uses based on local knowledge (peak hours in the Southcenter area) or peak hour trips for retail and offices uses based on national averages, since no data was available for the distribution of office traffic throughout the day. I am therefore not comfortable in stating that this project will have less traffic impact than the office building on Southcenter Boulevard. In addition, I have never received the requested memo from you verifying that an intersection impact analysis is not necessary for this project. With respect to your memo of November 18th, I have the following questions: 1. Your memo states that the traffic island in the southbound curb lane at the signalize access is to be evaluated for removal. Would this be a City project? Does this �....,�: ,',; project have any connection to impacts from this retail mall? I am not clear about your request that the signalized driveway detection loop be verified and turned over to the City with an easement. Is this an intended SEPA condition? In an e-mail message on November 1st, you indicated that "new access /turning movement trip" may need to be analyzed for this project. Was this ever requested? Was it, done? Please get back, to me on this as soon as possible. 46 4641411FTRF Municipality of Metropolitan Seattle Exchange Building • 821 Second Avenue November 28, 1994 • Seattle, Washington 98104 -1598. Diana Painter Associate Planner Tukwila Dept. of Community Development 6300 Southcenter Boulevard, Suite 1100 Tukwila, Washington 98188 North America's Best ifib101itt011.7af9941151131447.7:4911MMIZORMISTAWSWWWKSZED RE: Transit Issues and the Parkway Place Retail Center Dear Diana: Thanks for sending me the site plan of the proposed Parkway Place Retail Center, for review and comment. As you mentioned in your letter, there currently is a Metro bus zone /pullout with a passenger waiting shelter, located on Southcenter Parkway adjacent to the project, south of the signalized intersection. From the site plan, it appears as if the portion of the property adjacent to Southcenter Parkway, including the bus zone and shelter will remain unaltered by the redevelopment. Metro would prefer to continue using this bus zone. Prior to 1988, Metro utilized the Parkway Plaza parking lot and the signalized intersection as a bus turn - around for transit service that started /ended in this vicinity. There were only about eight daily bus trips that did this at that time. These buses would operate through the lot in a clockwise direction, entering from Southcenter Parkway by the Azteca restaurant and exiting at the signalized intersection. Although Metro has no current plans to resume turn -back bus trips here, it would be desirable to maintain this option for potential future use. Thanks again for the opportunity to provide these comments. If you have any questions, please call me at 684 -1597 Sincerely, otY e Doug Johnson Senior Transit Planner DJ cc: Roy Bennion Howard Turner RECE iv:; • NOV 3 0 1994 DEVELOPMEk Transit Department • (206) 684 -2100 • Mobility for the region PARKING ANALYSIS REQUIRED 155,115 SF @ 4.5/1000 = 698 STALLS PROVIDED STANDARDS = 484 COMPACTS = 202 (29%) HANDICAPS = 16 = 702 STALLS TOTAL • ..O-K----'11aL .L sozsec �Lt"'Ll „111:7"."71.7._ rt�'lrl1J IIl'Ili CI if if!}� r;l „cr• rrWit—rrl1�'liiI !illi1 /1RTFTAPJNC WALL ELEVATION VAC -.Td i / / ---� �. -� I, I I (,I bkdl I I I I— .I : ry, •nL _ _ I J i • r10.6PY/ WCYCLNC. ELEVATL T T t 4 4 4 4 I— VICINITY MAP STREET MAP 1 --I-- I—='';rL si•�_L_ - k====t------L—J--1 I I I 1 ._ 1 i.' 1 -'•-r I I I I I `., 1 I \--+--r _ r--I—•-- I G 1 1 I I _ -- I--tl--i- J —t"=— • r 1 .K ,E Bt.1 I/ Fi 01 NOTES TOIL - C-2 RCEa.•L KIM A NEW RETAIL 29,998 8 NEW RETAIL 40,045 /' W RETAIL 42,045 D ---PEW RETAIL 43,027 TOTAL NEW 155,115 • • • E EXISTING AZTECA RESTAURANT F EXISTING WINNERS RESTAURANT G EXISTING LEVITZ FURNITURE H EXISTING HERITAGE FUNITURE • • • —J •o.LECALVCEimSCIIiIPTCEAf•L rif:12�1G4DY • n/ii}��4.•al lKv111 •ii N•; AE Ag0511Nfl. f�T•-YM 14030.1 0501111 104 halm 1.. 1111*0l.,,r5..o a�>. .7ID:m ssn w,. u -o [.rulriiii,Km .4.3 .Pi.w, 4•o-. •i p0 o. 14 -Y-111 n14 11w1•11ly>f,•• MI d1 DS. i, ,AIN •i, rc0011114.nw..1•1 MO w M.LP'O, I•W NM! 10,11.1“.01. 441114111/01/ /11011.0.,04,Y 041 M,a PARKWAY PLACE RETAIL CENTER 17501 SOUTHCENTER PARKWAY TUKWILA, WA. • PARKWAY PLACE TURNER AND ASSOCIATES •40 leo ASCI•ItCTS SITE PLAN PARKWAY RAC. TUN.0 r:Iro• REVISIONS SHEET Al ATTACHMENT B m 1 t • OAST ELEVATION I oo. yea Ar Q M I t Wim t I TM I I 1 t 22 scALSVr ELEVATION o .•r I I I I I 1 I II 1 I 1_ 1 A.1 • la !I - \ _ ka �� OSOUTH-FdEVATON yr I I I ft arm Or OrJORTH ELEVATION rAcve-i-a. It; : iii 1:11t1{t lIVITtlttl Oft A%aD EAST ELEVA.,TItI of \ I • \ IDE_ _ _ _ MI/ / / / Jot (;\ENLMOED SCEINALK PAIN MOTES ®:181;1 ° i 'Own •m ►. O° d °e ORIN WOE P • OWED CCPCia S • SYNTACTIC IMAM MU AIM SYSTEM EP CI • Ar 6 W(coat XTE PARKWAY PLACE TURNER AND ASSOCIATES seas u.+c wM+o-r wl0li[CIS r•ap�sro. ELEVATIONS PIJMWAY PLACE. TU(WLA ray WO. rat REVISIONS SHEET A2 ATTACHMENT C .mow.-w+wrw ^^�' "1.t"N S�"'.[""iii V2flZ ••."' -"a+✓ { a4.t�•aawvs� IT VATgN n.... 1' ®WS,LUVATIO 4 SOUTH .EIEVAQ w ma 4a I i I /,TEVATIDNU . k &&ARCED EAST ELEvATCIN rn q I EE EnLARGEO SD WALK PA NICE NOTES e .ESKA .9.[ • . PAWED WOVE S .SWAM EMMA .91.40. STStis Ct . DASH 904 COd[E[ o . [NV= 960411 me PARKWAY PLACE TUSNER AND ASSOCIATES AROSTICTS . Z',.cMfor ELEVATIONS PARK -WAY PLACE. TIIEWLA RIV WOKS SHEET A2S ATTACHMENT D ?i> I 1 tri:, O O I I I f.- P ---- , OEE �lEVATCN 1 � -f4 1 OW ST ELEVATION S Vr rd W w G � I % O ONORTH ELEVATION w. r -td OSOUTH ELEVATION ._, yr-rV u .4.1 h EN_AROED EAST ELEVATION - BLILERJO A 5 yT-Id v u 1i tji!jii1illIItiIlit:Ra ;.1: i•':ii 1: "r ' :i L QEAROD EAST ELEVATION - B LEXJO q&D NOTES OfY aWW 60a oCTT ton N Cd NV C) i1 ralfii' 0Ia a oin4 a -a Qe1141 -E 8Dmtt oarrrt0 som IN .1300.6•1 WO( P AI.t1O WotIE S . `Smn(ta 01001 MI Ata SYSt1Y O .90.4 00. MOVE C2 . 09503 AW(Gtt 12C PARKWAY PLACE TURNER AND ASSOCIATES un1...P.ror 440//105 atrsw .r pq len MA ELEVATIONS Psalm AY RAX. TU(M(A • OAT REVISIONS 312125r/in SHEET A3 ATTACHMENT E TEAST ELEVATION V./WALL .me O.w OWEST ELEVATION LV:lr.fd v:w 4 I QPTH EV ATD''.,.. T OSSOUTH JLiEVATCN... QE£M RO EAST ELEVATION - BLDNO A ;_11111 14,01! till ill:i! u!linuni,!hi '7\ EN ARCED EAST ELEVATE - SULIOCG B & 6 w vl.Id NOTES Qa URI L OT ru . ammo Wm( P .PANaOmart 5 . zER AMATO SYSWW n . Erualnom moa 0 . On= AQ1rCATE OW. PARKWAY PLACE TURNER AND ASSOCIATES a▪ .m. ww. NMTECTS +...m N ULITO 0011110.11110 ELEVATIONS PARKWAY PLAQ. TUCALA '0 t o. REVISIONS 'SmWK-w SNEET A3S ATTACHMENT F OWALL SECTION ® ENTRY CC BELONG C W. Vf..4 LEPER PANEL (OWER PPJEL FROVCE (2) 00 SF FACES EA01 SCE `W-SIO3 SWIM FACE: UPPER PANEL LOWER PAEL NORTH FACE: LEPER PANEL LOWER PMEL NORTH 9OT SOUTH FACE: 11PER PAEL LOWER PAEL NORTH FACE: WEER PML LOWER PATEL TENANT C TENANT 0 TENANT A TENANT 0 TENANT B TENANT A TENANT 0 TENANT C OVi.1S ?ClIG SCR PROVOS (2) 97NS. T ORETANJO WALL SECTION Y�L VfA4 b.w 1' twat it •t... QcAau V2,1t. IQOETAL - PLAN OCOLU FOETAL - ELEVATION I 0 OSECTs.1.Vf+ONe w A TA+Av�•b•' atva S M OSECTION a...oon 1... ..A m.a. y..... W.Vfl4 I t U 9 • OSECTIONiC 1ao•m ooa, } wL Vfld b.wr NOTES PARKWAY PLACE TURNER AND ASSOCIATES u▪ mc.+.•a. MORTICES SITE PLAN PAf&NAY Ft AQ, TIKMN* ▪ vwMgt REVISIONS SHEET A4 ATTACHMENT G -1 I 1 1 I 1 1 I 4.-....--1.--/1/1 r 1 1 L 1 �- L-4I 1 I 1 1 I 1 1 1 1 1 ./ ( I 1 � .. . I . 1 1 t . 1 1 I I e / . E 1 I 1 OWALL SECTION ® ENTRY CC BELONG C W. Vf..4 LEPER PANEL (OWER PPJEL FROVCE (2) 00 SF FACES EA01 SCE `W-SIO3 SWIM FACE: UPPER PANEL LOWER PAEL NORTH FACE: LEPER PANEL LOWER PMEL NORTH 9OT SOUTH FACE: 11PER PAEL LOWER PAEL NORTH FACE: WEER PML LOWER PATEL TENANT C TENANT 0 TENANT A TENANT 0 TENANT B TENANT A TENANT 0 TENANT C OVi.1S ?ClIG SCR PROVOS (2) 97NS. T ORETANJO WALL SECTION Y�L VfA4 b.w 1' twat it •t... QcAau V2,1t. IQOETAL - PLAN OCOLU FOETAL - ELEVATION I 0 OSECTs.1.Vf+ONe w A TA+Av�•b•' atva S M OSECTION a...oon 1... ..A m.a. y..... W.Vfl4 I t U 9 • OSECTIONiC 1ao•m ooa, } wL Vfld b.wr NOTES PARKWAY PLACE TURNER AND ASSOCIATES u▪ mc.+.•a. MORTICES SITE PLAN PAf&NAY Ft AQ, TIKMN* ▪ vwMgt REVISIONS SHEET A4 ATTACHMENT G EXISTING SLOPED HILLSIDE ESS & EGRESS TL 141074DAIsCtiAVSOC 101.1111 RAZ a, PARKWAY ,PLACE. IUfMLA nb m ti SIGNALIZED INTERSECTION OSITF AN � rws PL -a STATE SLOPE & DRAINAGE EASMENTS ATTACHMENT J AREA CALCULATIONS 1. Existing Site Ar.. 070.948 4.1. low SOO... sap. M.. 153147 01. 'foal Non S.n.lo Sap. Landscape M.. _IL= ..1. TOTAL OXr5T111S CANOPY -139%N teed 1101 242.154..1. 0. Prepare! Action M.. 1. 5. A.nn..d ,loan 5.n.Uw Sap. Mw Mu 10 0. P.na.ed ban Non-S.wni.. Slop. Area 2024,. ANNA 70 BE 02110220 25.752 .1. _51405..1. 79.157 4.1. TWA Provided Canopy p,oposed 4n01c.ping 115.512 5 T. . •aa,r.0 u.6.4.d ..9.0000) -127.4% 011.Y11S11 : � ' iiyVYae� /eRBb' .e.�04.. Innen .'`' �'d �.6R�i�/t/Iv�4'�!/Gt4O 6h�Y.,r./� .../.v .widv,.. EYEING *NATION NTN MOPE AREA 10001morn n • NY PLAN/NG @ RETAINING MALL w.DI ...r NOTES w9.e.1111 RAR SOMME 0 0 c LAI IVPLAN.PS, lvadowagae.Archlanta= rand.a.0110 .aur 10•4 IOdOT{ 0 ..... o �._... .now. sass. 4.• . a. KAN, - 1il �ra i tires. y11.. ., .41• PARKWAY PLACE 1201[9 AND ASSOCIATES Nr. tom, 20.461 I.. pc) lata -n.. SI(E PLAN PARKWAY PLACE. RPM* REVISIONS 110 wllllf,llv.A.NYAM of f TREE Pf1Ul4G GIME SHEET ware P alio e�a.m..Trau L-1 . 2 ATTACHMENT K ilnr:at ¢ t TOrI Sart CANOPY rRA•rawT V. • d Z� LANDPLAN P.S. nt my A$I.4 �M PARKWAY PLACE TURNER AND ASSOCIATES AMONIEen tuna Ra.RMIllemrR rare CANS.. AREA -rYrr as. SITE PLAN REVISIONS stint' annum TNRtrIAN/ —wan rrr.EriAN- 417,/ JURYFYa a•77Cf /LO/N /7f. ATTACHMENT L 444) 4 000 City of Tukwila' John W. Rants, Mayor Department of Community Development Rick Beeler, Director ‘, ''‘ULe `'11A 04 (AA-0-VD .s November 16, 1994 Mr. Ralph Nichols ) Environmental And- Special 15700 Dayton Avenue North MS 138 Seattle, Washington 98133 -9710 Services Engineer Re Parkway Place Dear M1 . , Nichols: • C h ur , r►� �^--t� -! N U Enclosed is a set of plans, SEPA checklist, and accompanying reports and studies for the above project. This project is located east of I -5, just north of S. 178th Street in Tukwila. .It involves demolishing the nine story Boeing office building, and constructing 150, 0„00 sq. ft. of retail space. The applicant is proposing to cut into the hillside and construct a retaining wall of about 45' in height to accomplish this. We are forwarding this information to you prior to making a SEPA determination on the project because of your potential involvement.' There is a WSDOT drainage easement on the site that runs from east to west across the southern part of the site. • We would appreciate any preliminary comments you may have on the : ' project, and would be glad to meet with you to discuss it if this would be helpful. Mr. Bert Pschunder of GeoEngineers,.a sub - consultant to the applicant, has met with Bob Kinuaerling of your • Materials Laboratory in Tumwater to discuss his specific concerns,.. and Phil Ambrosino and Lynn Moses regarding the boring logs for I- 5. We would like- to make an environmental determination on this • project on November 30, 1994, if possible. If we can be of assistance to you in conducting this preliminary review, please do not hesitate to calla Sincer y Rick Beeler, Director Department of Community'Deve],opment ,1 cc Ron Cameron, City Engineer Roy Bennion, Parkway Place Partners Howard Turner, Turner § Associates 6300 Southcenter Boulevard, Suite #100 • Tukwila. Washfnpton 08113R • (206) 411 -.1670 • Far: (20J 1-3665 Attachments: 0. Project plar}s,, received 11- 10 -1994Y ( B. Revised SERA Checklist, received 11 -10 -1994 C. Report - Geotechnical Engineering Services, received 11 -10 -94 D. Report - Bush, Roed & Hitchings, received 11 -10 -94 'E. Report - EnviroBusiness, Inc., "Phase II Limited 'Subsurface Investigation'," received 11 -10 -94 0. Report Arthur. D. Little, ! "Environmental Baseline Assessment," received 11 -10 -94 (attached to above) F. Report- Talasaea Consultants, "Sensitive Areas Study Report," received 11 -10 -94 G. Letter, Michael Sandorffy, Parkway Place Partners, "Canopy Removal," received 11 -10 -94 H. Letter, Landplan P.S., regarding canopy removal, received 11 10 -94 .I.• Letter, R.W. Rhine, Inc., regarding demolition, recieved 11- 10-94 J. Letter, Michael Sandorffy, regarding tree removal, recieved -.. .11-3-94 . PARKWAY PLACE RETAIL CENTER SENSITIVE AREAS STUDY REPORT ADDENDUM TO REPORT AS PREPARED BY: TALASAEA CONSULTANTS WOODINVILLE, WA ADDENDUM PREPARED BY: LANDPLAN, P.S. EDMONDS, WA 98020 9.3 Mitigation for Tree Removal Impacts LandPlan, P.S. has developed a Tree Replacement Plan in order to replace the trees lost to clearing (25,752 s.f). Under this plan two areas (approx. 23,000 s.f.) on the site have been identified for possible tree replacement. One a rectangular area along the site's western boundary (Figure 5) is proposed to receive 53 1' -2' saplings consisting of a mixture of 2/3 Douglas fir (Pseudotsuga menziesil) and 1/3 big -leaf maple (Acer macrophyllum). Additional tree replacement has been determined to be required in lieu of displaced trees resulting from the "geo- technical" soil boring operation. Specifically an additional 50 1' -2' saplings consisting of a mixture of 2/3 Douglas fir (Pseudotsuga menziesil) and 1/3 big -leaf maple (Acer macrophyllum) trees within the rectangular area along the site's western boundary as described above. The second area is in the southernmost portion of the site, within the buffer of Wetland A, and would contain 29 saplings. Proposed planting in this triangular area consists of a mixture of Washington or Polack hawthorn (Crataegus ...). 11 -29 -1994 O4 :50PM FROM SEP —TAC TO 3557504 F'.02 gOareiNaira clSoaraeo " CO " icy . • .•.SPMCRFI.CATIONS : - '.... 1. Die-formed steel housing finished with white polyester powder baked enamel. j • : • 2..:Adjustable rounting.brackets with integra} nailer tabs. 3. Horizontally mounted medium blase porcelain socket with nickel - plated screw shell, ' 44.• ; ;piltuseanodized elurj inuiii reftecter:: •'5:" Galvanized steel junction box with bottom-hinged access covers and spring latches'. Three combination _ 1/2' - 3/4' and one 1/2' knokouts; are provided which allow for straight thru condylit runs. Capacity: 8 (4 in - 4 out)•No..12 AW..G conduct3brs, rated for 75° C. PrewfredHPFcore'and;coil Lttast{ .. �.-.• . �• ±':sue ::yY10te:Dolyeste.r powder bak a ly .;" • , ..,•:.... . elf :aliantnO` and. •'constan • tension:: sup o springs... :.} ::_ , P -.'' Ok sre.? CA7.N0. ,_^,1411 _ _...i, :::. • . • • • spic>fp.Votttpi `!20227•.•, Semi -Mush Symmetric Square Lens Downli ht 1 HIGH INTENSITY DISICHARGE i 70W,100W Metal Halide 50W-100W Mercury Vapor SOW -100W High PressuF* Sodium ORDERING INFORMATION 5. Catalog ,._ • Number'' -, ..- �Sadiesijfiaiirp`iyipe • ..LAH 7QM 11 SFL' ^,f... aid -.. :L'Aff Till RW, .,::t4telat}}i e,;::,'�Aq; S,F eta! gilds.`' ;- :1�AA,fC/lt''r: �'.•�,....... • X100 •�.11R11�'• M • It.50H Atlir• °SFL ` 'Meceiht Vapgi r }T4Sf46PL4t? O1DX': . LAH:.1511 11RW: SFL :.:,.:MetduryW o'r, ,N43AV- 75/PX? ': LAK'1001ii 11RWiSFU:••' Merctiryllapof' .63SA9;11107bk • • :LOC 50S:1.1RW SFL ' .HPS'.1.- . ' 1150/WMED,• .., - ': LAN 70S• 1.1RW SFL ... :" HPS ' , trU1a IMEq.... LAN. IQ05':f 1RW.; SFL " : :. fin '. + . •• a-t11O01D/t+eor. . + Voltage I 20 or 277 must be specitted. Ex: LAH 70M• 11RW SFL.120 - ADOITIONAL ORDERING SNFONMATION . : OQ'p�tiiJone •:;Orryde�r�a�s�sul9>GtoA_ato0 number.++,�_-:_;. , .::. ' ' :.. • , .._, • &A - t,..,^A011'i:.•TM <47:1 41tl.:nr•411!'I J:^•:X9a"_. :1 ir•,r •b',,•w.l«`• ;r ORS Quartz Restdk'e•Syistn�(uses O:CS� quuizirip ••. - by others; roll ium =10OWy EC Emergency Circuit (D.C, base;socketwith leads for connection to emergency po+'ersource; maximum • 100W) • SSC Provides compatibility with Lithonia Retie Connector System 820: The 820 System pan hehtstalled leas this option with connectors provided by others. Accessories • Order as separate catalog number. Cat, tip; Description • 8824 . • 24'•stool bar hangers (2) for)'; bill moaii�riq: " " " ' :: NOTES• LSMC Setot4?- barmountinp`ctlps'j -•' For more details see Submittal Sheet ACC -1. 10 -1 /8'. 11.1/4' • • . 23' • 1. Fixtures ue lt.1.1572 listed foT Wu-inane/1 circuit wiring, recessed and damp location. 2, See back of this sheet toe atecUical operating data. UPPER PANEL LOWER PANEL PROVIDE (2) 100 SF FACES EACH SIDE SOUTH SIGN: SOUTH FACE: UPPER PANEL LOWER PANEL NORTH FACE: UPPER PANEL LOWER PANEL NORTH SIGN: SOUTH FACE: UPPER PANEL LOWER PANEL NORTH FACE: UPPER PANEL LOWER PANEL TENANT C TENANT D TENANT A TENANT B TENANT B TENANT A TENANT D TENANT C WNW 1 FREESTANDING SIGN PROVIDE (2) SIGNS. SCALE: 1/8"=1•-0" REF: 1 -Al DATE: 12/1/94 SCALE 1/8" = 1'-0" FILE: PW\POLESIGN s1 TURNER AND ASSOCIATES 18420 24th PLACE N.E. SEATTLE, WA. 98155 ARCHITECTS TELE: (206) 365 7431 FAX: (206) 365 7504 PARKWAY PLACE 17501 SOUTHCENTER PARKWAY TUKWILA, WASHINGTON sKet/ 'itonWldhit To 'dG mE'tEMt*460 QI') --°- -- o.c.. RETAINING WALL SECTION SCALE I /2 " —P —O" REF: 1—Al i i i i ��i 1 1i ri li HMI MINN 1i MEM BMINIM MIME MEN 1i♦ /MINI a�1 1111■11 MEM li•1•1 MINIM Iii 11th ii MINIM MINIM �o11i 1111111 i•M si iii■ mom mom loom mom, Immo MINN 1ri• tam OEM MINIM ii Iii ti•n ti• 11■1111 11� ltd !t• 1� !ti !tM 11• 1i 1i 1i INN INN ti Int 1� In In Ir In It 1! In In 1r In 1■ a 1— csi co j, 2- 8.-4- I 3 3 3 } O i ti la 1n O I N cJ 4 I t i•t 1 SECTION C (SECTION ROOF RIDGE) SCALE: 1/2 " =1' -0" REF: 1—Al COVERED WALKWAY RETLRNS 50' TYP. AROUND CCR ERS BEYOND NO COVERED WALKWAY ,.LIST PLASTERS W DRYVfT ■J1 to. DEWALK ( PLANTER OSEO1O\ B (WALKWAY ® NOTH & SOUTH ELEVATION) SCALE: 1/2 " =1' -0" REF: 1-Al v • COVERED WALKWAY TILT —UP PANELS BETWWEN ENTRIES UNINSULATED SPACE - BEARING i PLUS 1/2 C JOINT PS 2' -6' x —ti SQUARE COLUMN TYPICAL 1S LOCATONS Ls% cV iV iV J b INTERCR HEATED SPACE 1 SECTION A (WALKWAY EAST ELEVATION) SCALE: 1 /2 " =l' —O" REF: 1 —Al 9411082152 ORIGINAL RELEASE AND QUITCLAIM 381 -95 RFC:F:1\1.--T) NOV 1 01994 y DEVELOPMENT Ad J�This Release and Quitclaim is made this 3 -- day of ems, wL,, 1994, between UNION PACIFIC RAILROAD COMPANY, a Utah corporation ( "Grantor "), and THE PERSON OR PERSONS AND /OR CORPORATION OR CORPORATIONS TRACING HIS, HER, ITS OR THEIR TITLE FROM JACK A. BENAROYA COMPANY, A WASHINGTON CORPORATION AS IT RELATES TO THE EASEMENT RECITED BELOW ( "Grantee "). WHEREAS, by instrument dated July 16, 1976, the Jack A. Benaroya Company granted a perpetual easement to the Chicago, Milwaukee, St. Paul and Pacific Railroad Company, a Wisconsin corporation and the Oregon - Washington Railroad and Navigation Company, an Oregon corporation, and its lessee, Union Pacific Railroad Company, a Utah corporation for the construction, maintenance and operation of a lead track upon, over and across certain property in King County, Washington; WHEREAS, the Grantor named herein is the successor in interest to the easement rights received by the Chicago, Milwaukee, St. Paul and Pacific Railroad Company; WHEREAS the Oregon- Washington Railroad and Navigation Company was merged into the Oregon Short Line Railroad Company on December 29, 1987, and on December 30, 1987, the Oregon Short Line Railroad Company was merged into Union Pacific Railroad Company; WHEREAS, the Grantee named herein desires that the Grantor named herein release, relinquish and quitclaim its easement rights in and to the property described in Exhibit A, hereto attached and hereby made a part hereof; and WHEREAS, the Grantor is willing to release, relinquish and quitclaim its rights in and to the property described in Exhibit A, hereto attached. NOW, THEREFORE, the Grantor named herein in consideration of One Dollar ($1.00) and other good and valuable consideration, the receipt whereof is hereby acknowledged, does hereby REMISE, RELEASE, RELINQUISH and QUITCLAIM to the Grantee named herein, their successors and assigns, forever, all of the Grantor's right, title, interest, estate, claim and demand, in and to the property described in Exhibit A, hereto attached, which the Grantor has by reason of said easement dated July 16, 1976, as referenced above. EXCISE TAX NOT REQUIRED Kin o.Rtecord Divi on PutY 941108 -21M2 03:08:00 PR KING COUNTY RECORDS IN WITNESS WHEREOF, the Grantor named herein has duly executed this instrument as of the date first herein written. Attest: Assis a � Secretary (Seal) 9411082152 UNION PACIFIC RAILROAD COMPANY, By Assistant Vice President ACKNOWLEDGEMENT STATE OF NEBRASKA ) ss. COUNTY OF DOUGLAS ) The foregoing instrument was acknowledged on this 3'__ day of /vove,,ja, , 19, before me, a Notary Public duly commissioned, qualified and acting, within and for the said County and State, by R. h. a 4.,,/ r c,t and , to me personally known, who stated that they were the /6s4 11,c. /4, es' eleip 0L- and Assistant R. C. INGRAM tg Secretary, respectively, of Union Pacific Railroad Company, a Utah VI corporation, and were duly authorized in their respective Q capacities to execute the foregoing instrument for and in the name • and behalf of said corporation, and further stated and acknowledged O that they had so signed, executed and delivered said foregoing instrument for the consideration, uses and purposes therein mentioned and set forth. Notary Public My commission expires: L: \GEN \481- 95RQ.147O UNION PACIFIC RAILROAD COMPANY Tukwila, King County, Washington M.P.171.41 - Seattle Subdivision EXHIBIT "A" 0 To Vol Release . hou An irregular strip or parcel of land situate in the SEhSW1/4 of Section 26, .y 0 Township 23 North, Range 4 East of the Willamette Meridian within the City of 914 Tukwila, King County, Washington as heretofore acquired by Chicago, Milwaukee, `4» 94 St. Paul and Pacific Railroad Company (predecessor to Union Pacific Railroad TP Company), Oregon - Washington Railroad and Navigation Company (predecessor to ., Union Pacific Railroad Company) and Union Pacific Railroad Company from Jack A. Benaroya by Easement dated July 16, 1976, recorded in Volume 1177, Page 54 of the records of said King County, Washington. An irregular strip or parcel of land situate in the NE'NW1/4 of Section 35, Township 23 North, Range 4 East of the Willamette Meridian within the City of Tukwila, King County, Washington as heretofore acquired by Chicago, Milwaukee, St. Paul and Pacific Railroad Company (predecessor to Union Pacific Railroad Company), Oregon - Washington Railroad and Navigation Company (predecessor to Union Pacific Railroad Company) and Union Pacific Railroad Company from Stanley N. Kasperson A. by Easement dated April 22, 1970, recorded as Document No. 6643574 in records of said King County, Washington. Office of Contracts and Real Estate Omaha, Nebraska September 6, 1994 Revised November 1, 1994 Written by: DDB TUKWILA.WA 381 -95 . ... ... ',.,.... Questions: Applicant SEPA Checklist • Sensitive Areas issues (including tree preservation ordinance) • Demolition impacts should be addressed separately • Address spillway at north end of site • Address "State Slope and Drainage Easement" (S. end of site) • Address "Easement for Ingress and Egress" (N - S on site) • Questions regarding Traffic and Geotechnical should be addressed specifically and not referred to attachments Traffic Report • AM and PM Peak hour figures for project are not applicable since peak traffic in the area occurs at noon • Is the reduction of AWT because of "Pass -by and diverted linked trips" an industry standard (i.e. from ITE Trip Generation. 1991.) or the opinion of TPE? Geotechnical Report • Alluvial deposits proposed to be removed and replaced: how much? where will it go? • What are the ramifications of building over the "compressible alluvial soils "? • Sentence, page 3, top is garbled. Utilities Report • Impervious surface area increases rather than decreases - addition is incorrect (note also that total site area is increased by approximately 52,000 square feet) Design Review Application • (See notes requiring clarification) Site Plan • Topographic plan (finished grades, 2' contours, and grades for slopes over 15 %) • Compact parking stall location • Where are handicap stalls for building `B" Pagel ~ l 1:54' P1VI 10/27/94 . Landscape • Note that landscape area is reduced from 51K sq.ft. to 47.9K sq.ft., a change of 3.1K sq.ft. • What are measures for the protection of existing trees during construction • Are Large oaks nearest the entrance of existing building to be saved? Architecture • Building Dimensions • Building set backs • Lighting specification • Roof top mechanical equipment location and size • Business sign size and placement • Building colors (samples ?) • Building materials • Plan of entry • Section through entry doors • Section through secondary portal • Section through arcade Page2 11:54 PM 10/27/94