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SEPA EPIC-33-88 - SOUTHCENTER GATEWAY ASSOCIATES - RAINIER RIDGE APARTMENTS
RAINIER RIDGE APARTMENTS PROPOSED BUILDING OF APARTMENTS SOUTHCENTER PARKWAY S. 178T" STREET EPIC 33 -88 CITY OF TUKWILA 6200 SOUTHCENTER BOULEVARD, TUKWILA, WASHINGTON 98188 June 10, 1991 PHONE # (206) 433.1800 VIA CERTIFIED MAIL Mr. Dan Kelley, President The Holly Corporation 101 East 26th Street Suite 301 Tacoma, WA 98421 Gary L. VanDusen, Mayor RE: Proposed Rainier Ridge Apartments in Tukwila, Washington Environmental Review (EPIC 33 -88) Board of Architectural Review Application (89 -1 -DR) Building Permit Applications (CN 88 -393 through 88 -398) Dear Mr. Kelley, Pursuant to my letter of February 8, 1991, your building permits for development of the Rainier Ridge property expired at the end of business on May 6, 1991. At this time, all of your building permit, environmental and B.A.R. review files have been closed out. Please immediately contact Vernon Umetsu of my staff at 431 -3684 if you have any questions. L. Rick Beeler, SEP Responsible Official Duane Griffin Building Official cc: City Attorney/ Den se; Mi 11 and •SENDP11: Complete items -1 and 2 when additional services are desired, and complete items 3 anc■ : .1 (- Put your :-. ,ress in the "RETURN TO" Space on the revi. ;ide. Failure to do this will prevent this card from being returned to you. The return receiptfee will pro you the name of the person_delivered_to and the date of delivery For additional fees the following services are available. Consult postmaster for fees 2. 0 Restricted Delivery (Extra charge) anf check boxies) for additional service(s) requested. ' 1. 0 Show to whom delivered, date, and addressee's address. _ -- - -- (Errs charge) - 3. Article Addressed to: Dan Kelley, President The Holly Corporation 101 East 26th Street, Suite 301 Tacoma, WA 98421 4. Article Number P 543 -090 855 Type of service: III Registered II Insured Certified • COD ❑ Express Mail Retum Receipt `_ _ __ _- for Merchandise- _ Always obtain signature of addressee or agent and DATE_DELI VERED. 5. Signature - Addressee X 8. Addressee's Address (ONLY if requested and fee paid) 6. Signature •.j, t •iii. fir_ 4 7 VW, r t, !. 7. Date of Deli _rryry :' PS Form 381 1, Apr. 1989 DOMESTIC RETURN RECEIPT *U.S.G.P.O. 1989 -238 -815 UNITED STATES POSTAL SERVICE OFFICIAL BUSINESS SENDER INSTRUCTIONS Print your name, address and ZIP Code in the space below. • Complete items 1, 2, 3, and 4 on the reverse. • Attach to front of article if space permits, otherwise affix to back of article. • Endorse article "Return Receipt Requested" adjacent to number. RETURN TO u0 PENALTY FOR PRIVATE USE, 8300 Print Send 's name, address, and ZIP Code in the space below. t-'4\b/J ) )\ i\tAir5(A CITY OF TUKWILA 6200 SOUTHCENTER BOULEVARD, TUKWILA, WASHINGTON 98188 VIA PHONE # (206) 433.1800 CERTIFIED MAIL Gary L. VanDusen, Mayor February 8, 1991 Dan Kelley, President The Holly Corporation 101 East 26th. Street Suite 301 Tacoma, WA 98421 RE: EPIC 33 -88: Rainier Ridge Environmental._Impact Statement. Dear Mr. Kelley, The Rainier Ridge apartment project was grandfathered for 108 units with a building permit application just prior to a down zoning of the property. The 180 day period for completing all building permit activities was frozen in place when a determination of significance was issued. Freezing the building permit clock was conditional upon continued progress in completing the environmental impact statement. We have seen no progress on completing the Rainier Ridge environmental impact statement since October 16, 1990. Bill Betlock of your office was advised on October 17, 1990 that this lack of progress would lead to a restart of the 180 day building permit clock. Once the remaining time on the building permit expires, all vesting in the previously allowed housing density will be lost. There are 71 days remaining in the building permit period. This is 180 days, less the 109 days between building permit submittal (12/22/88) and the determination of significance (4/10/89) as discussed in the Planning Department letter of June 12, 1989. NOTICE: You are hereby notified that the 180 day building permit completion period shall. restart unless the following steps are taken: 1. An environmental impact statement consultant is recommended for selection by the City, either from the two groups already proposed by your office and approved by this department, or another group, by February 22nd; and • • 2. The projected cost of draft environmental impact statement preparation pursuant to the final E.I.S. scope of June 8, 1989, is deposited with the City within ten days after you are notified of consultant selection. The projected cost will be negotiated by the City with the selected consultant; in consultation with your representative. The building permit time period will be restarted with no further notice should these conditions not be satisfied. Please do not hesitate to contact Vernon Umetsu of my staff at 431 -3684 if you have any questions. L. Rick Beeler, SEPA Responsible Official CCU Duane Griffin, W Building Official Attachments A. Planning letter of June 12, 1989. B. Threshold Determination of June 8, 1989. ?/.41- At° Acc kAILA er Assu2� V� a2 12/88 Submit SEPA checklist. 1/9/89 Submit BAR app. (108 units by Polk) 1/11/89 SEPA distributed to all departments with 1/19/89 comment deadline. Various meetings with applicant, engineers, and architecture teams. 4/3/89 Applicant submits additional information to supplement checklist, and reviewed; feasibility of 76 unit option by Berry & Berry. Option not pursued. 3/23/89 Soils report submitted. 4/10/89 Determination of Significance; EIS required. Scoping to begin. 4/26/89 Receive Dan's & Moore bid to do City's review of applicant's geo -tech work. 5/1/89 Comment period for EIS scope ends. 3/28/89 Important PW /planning meeting to review additional checklist data needed. 6/8/89 Scoping established. 12/89 Various meetings between Betlack and Umetsu to explain again EIS process. 6/12/89 Meet with Betlack to review scoping. Applicant to look at alternate project design. 7/7/89 Betlack talks with cameron and Fraser regarding soils. 8/17/89 Beeler reaffirms EIS required even if project reduced to 70+ units per Berry & Berry alt. 9/18/89 Holly Corp. agrees to proceed with EIS. 9/27/89 Lawrence's formal response to 6/8/89 EIS scope submitted. Previous period spent in classifications and looking at developing options with staff. 10/3/89 Dan's and Moore surface soil review submitted. 11/4/89 11/13/89 11/13/89 11/13/89 No Date 2/12/90 3/5/90 5/8/90 4/23/90 5/10/90 6/27/90 7/5/90 • • • • Beeler modifies EIS scope in response to Lawrence letter (9/27/89) assuming Berry & Berry (70 units off slope) is now proposed. Rick Lawrence (Holly) requests appeal of EIS scope. Dick Chopin (Holly's att. the proposed action; not Beeler notifies Lawrence appeal period requested letter. clarifies that 108 units is the 70 unit option. that he cannot extend the in the 11/13/89 Lawrence In light of withdrawn Berry & Berry alt. and continued on slope units, the June 8, 1989 EIS scope is to be used. Meeting between Bill Kroeger, Mither, and Umetsu to start Mither as new project architect. Mither to develop new plans. T -MAC (Dick GGE) declines meeting with developer. Fears being compromised. FAX Kroeger EIS scope. Ownership of project passed from Polk to Holly Corp. Mither submits new plans. End of reconstructed project chronology. Umetsu confers with Beeler regarding small triangular piece of site now in Sea -Tac and previously in King County. Only landscaping and very minimal land alteration in place. Beeler determines to work with Sea -Tac in EIS process since actions do not require permit. This issue discussed earlier when piece was King County. Bill K. informs me that Holly will proceed full speed with approved alternatives. V.U. explained consultant "arms length" relationship with developer. 4J�w��a vv./4;c City of Tukwila _ Z MANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 •1908 FAX TRANSMISSION DATE /TIME • /8[ /l p O TO: l(-C- KK114. G672) M(-ow PA-fzi, 623 - 7ooS (Name) (Company Name) (FAX #) FROM: X1V0^r FAX #: 433 -1833 PHONE NO • '433- / 8 S 8 SUBJECT- /244in/, Cn /e/ D G SGT Pe- PAGE(s)• (1(+ Cover Sheet) COMMENTS: HAROLD R. IVERSON PRESIDENT • • SAMMAMISH COMMERCIAL CO.. INC. 11715 S.E. 5TH ST., SUITE 100 BELLEVUE, WASHINGTON 98005 454 -0646 April 23, 1990 Mr. Rick Beeler Planning Director, City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 APR 25 1990 CI TY" Re: Holly Homes Project South 178th Street, West of Southcenter Parkway Dear Mr. Beeler: I have met with Rick Lawrence and Dan Kelly of Holly Homes recently, and Wells McCurdy and I have authorized them to proceed with the project mentioned above, with their architects, Mithun and Associates. They informed me that in connection with that project, there was a need for a document in your file evidencing the termination of the William M. Polk Trust. There is enclosed the recorded termination of that trust, and a quit claim deed, placing the title to the property back in the names of Wells B. McCurdy and Sammamish Commercial Co., Inc. If there is any further documentation needed, or if you have any questions, please contact me. Thank you. Very truly yours, SAMMAMISH COMMERCIAL CO., INC. 144,4( By: Harold R. Iverson, President HRI:mn Encl. cc: Mr. Richard Chapin, 8908081119 TERMINATION OP ME WILLIAM POLK TRUST THIS AGREEMENT is made this rd •• day of August, 1989 between William Polk, Trustee, and also referred to as Successor Trustee, and Wells McCurdy and Harold Iverson, the Trustors and Beneficiaries. IN CONSIDERATION of the mutual covenants and undertakings of the parties hereinafter set forth, it is agreed as follows: 1. The Trust established by the Declaration of Trust dated October 12, 1987, wherein William M. Polk is designated Trustee and Harold R. Iverson and Wells B. McCurdy, Beneficiaries and Trustors, is hereby revoked and terminated. The Declaration of Trust of that date describes as the subject matter of said trust certain real estate situate in the County of King, State of Washington, described in said trust agreement and, in addition, there was subsequently added a parcel, the legal On description of which, together with the legal descriptions r1 of the initial parcels, are attached hereto and incorporated r♦ by this reference. r♦ m 2. This revocation is effective upon execution of this G instrument by all of the designated parties. LD CI3. This agreement is fully binding upon the heirs, LD administrators, executors and assigns of the parties. DATED this 3rd day of August, 1989. William M. Polk, Trustee and - uccessor Truste Be e i iary and T s Beneficiary and r stor 8912010417 'TICO TITLE INSURANCE Filed for Record at Request of AFTER RECORDING MAIL TO: Rasperson & Bittner, P.S. 1700 Pacific Building 720 Third Avenue Seattle, WA 98104 • TIM a►AM M$L V!D MO nBCOIO[A1 USE KING COUNTY NO EXCISE TAX DECO' 1989 E1101209 89/12'01 REC) F RECFEE CRS iSL .RECEIWIrriff'rVAT OEC 1 11 33 AM '89 BY THE DIYI,i3N OF RECORDS & CLEC I IG,NS KING COUNTY #0417 E 11.00 2.00 ** *13.00 55 1pW L 56 ow, Corrective Quit Claim Deed THE GRANTOR William M. Polk, successor trustee as 'to Parcels '1 through t4 4; and William M. Polk, Trustee as to Parcel 5, Ca' O tbrAntaktKCOKSititnedata for good and valuable consideration O oonvcys and quitclaim; to Wells B. McCurdy and Sammamish Commercial Co., Inc., C4 a Washington corporation rq the following described real estate, situated in the County of Ring O co By By State of Washington including any interest therein which grantor may hereafter acquire: The legal description is attached and incorporated by this reference. This deed corrects that certain Quit Claim Deed dated August 3, 1989 recorded under Auditor's file no. 8908081119, August 8, 1989, E 1077505, by correctly designating the grantees. FILED FOR RECORD AT REQUEST OF TRANSAMERICA TITLE INSURANCE COMPANY 320 108th Ave. N.E. P.O. BOX 1493 RPIIevue, WA. 98O Dated this 30th day of November, 1989 STATE OF WASHINGTON COUNTY OF _Alma } On this day personally appeared before me William M. Polk as to me known to be the individual described in and who executed the within an foregoing instrument. and acknowledged that and •••signed the same as free and o ( y ag, s i decd, for the se uses and purposes theus•mention ' ;tat ; ••^ GIVEN under my llpod 1n51 otngafseaai this 3.41 days .l'4+6_4.46.» »Y.7 i9 .^..(.. o st • Notary Public in !Drell a State of,Waahirsgton, reaidingat ..... My appointment e:A.0n By �...�.✓ f Wil am M. Polk, Successor Trustee, as to Parcels 1 through 4; and By William M. Polk, Trustee as to Parcel 5 rte.. STATE OF WASHINGTON COUNTY OF } On this ..._.. day of 19 , before me. the undersigned, a Notary Public in and for the State of Washington, duly commissioned and sworn. personally appeared u and to me knuun to be the President and Secretary, respectively, of the corporation that executed the foregoing instrument. and acknowledged the said in- strument to be the free and voluntary act and deed of said corporation, for the uses and purrwsses therein mentioned, and on oath stated that authorired to executed the said instrument and that the seal affixed is the corporate seal of said corporation. Witness my hand and oiTirial seal hereto affixed the day and year first above written. Notary Public In and for the State ofWashington, residing at ...„»._.._ ................ »...»..». _............ My appointment expires on ......»...»... »» 8912010417 8908081119 8710150262 BEST ( AVAILABLE 1. .ml n a- 11tnlrsloa , teR portion ' Iliac Kip 23 oiorchh.. Songs � s44 at 4V.L wcribedses fool Section 33. Iat the t owner of the Northwest 1/4 of the Nortboset the at .aut tacUL@ 3s: thence bath 01.49'41- vast along the goat )4n1 of the 9bt:Lr..t 1/4 of the Phu-thaw 1/4 of *aid Section 33 a distance of 737.011 feet to the North margin of loath 1711th Street (P.J. Mu l�e la): G thence Norh 63'22'03" Jut along said North 'barite �dita wi .y 240.64 feet: 14 thence North 47•46'03" out along said North margin a11ddistance of 341.00 tut to the Let right -of-w7 ltn. of ?dreary No. 1 p,metiaa S. S. S. So. U to South 17Sih Smooth thanes Nord+ 09'32'33" Lot slang said Nest right -of •1 7 line • • distance of 240.39 fit: dios of 11.199.16 feet, thanes along a eerie to the right. laying a a to the North ltaefof the Northeast feet fortheast 1 4 of the Northwest 1/4 of art distenca thence South $7.43'37' gu Section 33; t . •aid No 1a North 1e • distance of 419.1. 1cn feet to the true point of beg l ° "11: together with that portion of vacated south 178th Street adjoining as disclosed by • King County Ordinance No 8238, which upon vacation attached to said property by operation of law. Situate in the City of Tukwila, County of Ring, State of Washington. Page 1 of 3 PIP" coatiawd - • BEST AVAILABLE . - ••': nnigaffiliga Sachs s•. 534464 set= (a ntia..d); LIMA, n ot pstio0 of the Northeast 1/4 of the Northwest 1/4 of ad Section 33. Township 23 North. gasp 4 loot ao follows, • beginning ac the Northeast ..r..r of .aid 9orthaaat 1/4 of the Northwest 1/4; thence North 87'43'37' Meat along the Nord Liao of said N ortheast 1/4 of the Northwest 1/4 • dlatane..f 481.03 last . co the Wet margin of the Sootscent.r larim.7s thence South 11'59'33" Last along said Vest margin a distance of 1.007.07 1..t; thence continuing South 11'39'33' Tact aim said margin. • distance of 94.03 feet; thence South 76'00'27' Meet • distance of 46.93 feat to on angle pint of the old ali6sr•sst of South 178th Street (f.r...rl7 know as 9. J. bagful Comm Read); • •ttrr.at e ddletance .4 221..299 along et too as old .�30t! Borth .1 and p••rzallel'to the South ii.e of said Northeast 1/4 of the Northwest 1/4 Ming the North.margia of the sew alignment of said South 178th Streets a distance thence ▪ 233.01 foot too* *.ingot along North mmtil�ni�h thence ofg113.24Nfeet. margin n are diatanee .f 1,4994.17 foss. through • central angle of 63'33'34" to a pint of reverse curve: thence along said North margin .0 • cure to the left bowing a radius of 260.74 feet, an arc distance of 20.43 foot. through • central soils of 06'16'32" to the old concertina of Said South 178th 'ergot; these. North 29'42'27' lost along said old centerline • distance of 32.69 lest to en angle point. �2. t said distance 04 04 .; c. Oa North argi. of the s alignment off s South 178th Street to the .trvs pint of Maiaging' t/s used for lamas reference .see of herein lies Northt37.33vhi "h L test • distance of 173.09 feat; a cores to the loft. cD. Waco along said North margin m c oaf 266.74 bats as arre diseases3.f3137.30cfhetsthrough • central angle of 33'34'46'; thence North 60'38'10' Yost alms said North margin • distance of 204.96 feet, themes aloog a acre to the left laving a aa al radius of 508.59 feet. an are distance of 23.32 Lot through r 02'32'29"; North thence 0w lest osi margin distance of 290.feet toth. Vase lima f ad I.rtheo/ of h Northwest 1 /411 af m=s I oot3a • ' • BEST £' AVAILABLE 8912010417 eel 1 Order So. WAN jlSCR11'TIOS. PARCH t leontlaood)s these. north 31.41•11' Lot Ware said Seat Use to the South Use of the r.rth...c 1/4 of the Norchma.t 3/4 of the Northwest 1/4 .f said Section 3S1 thane festally aloes said South Use to iataratt • line which Mars O.tth s2 44'03' Vest !meth. dotou.atics.d Polar 'A's theme South S2•44.13' Seat to said Point 'A'. which pint 1. the vest Southerly corner of • tract of lead conveyed to Americas Notional Invente by dad recorded 0ctober 16. 1370 ..der Ltordin& No. 47041130, thence South 37•33'33' Vest 173.01 feat to the tram }olat of begimlai s Situate in the City of febrile. C.mty d 1Aeg. Scat* of DEC 11989 Filed by TA • BEST AVAILABLE a Order No. 634444 piSCt11110e (eentim ed), TOCCi 3'. Shat portico of the BbTNaa■t 1/4 of t o Portlawac 1/4 at Seccf. 33. Temoship 23 North. bangs 4 Vast 9.11.. &ascribed as follows, begimint at the Northeast owner of said Northeast 1/4 of the Northwest 1/4; thence North 87'43'37" Vest along the North Ilea of said Northeast 1/4 of the Northwest 1/4. • discanae of 411.03 lest to the Teat margin of touthes:nes 9ariway; thence South 11'31033 gut elan{ said Vest margin. a distance of 1007.07 feet to the true pint of ►.Simmiat: thence continuing Vouch 11'3933" t aloes nail ma:gte. a distones of 94.03 feet; o thence South 711'00'27' Vest, a distant* of 68.93 feat to an angle .4 point of the old alignment of South 178th Street (fozaQly knows as p. W County T. J. sia1 Coty goad); thence South 20'03'27" Vast along the old eenterlia& of said street. a distance of 221.29 fast to a line 30 feat North of and parallel to the South lies of said Northeast 1/4 of the Northwest 1/4, being the North margin of the new alignment of said South 178th Strut; thence North 87'30'57" Vest along said North margin, • &stance of 233.08 feet to a point of curve. thence along acid North margin on • curve to the tight lariat's radius of 113.24 feat. en arc distance of 169.17 feet. through a central angle of.85'33'34 ".to a point of reverse nave. thence along said North margin on a cure to the loft. having a radius of 268.74 feet. en arc distance of 29.43 fat. through • central angle of 06'16'32" to the old ceatarlfea of said South 178th Street; thenra North 29'42'27" last along said old centerline. • distance of 32.69 feet to an angle point; of thence North 35'08'13" Meet along said old menterlins. xth w sadi e llich 64.04 feet to the N marglm of the m altssenc South Street; thence North 37'33'53" Vast 173.09 feet to the most Southerly corner of • tract of lend coaveysd to American National Iararsrce by deed recorded October 16. 1970 &dor &cording No. 6704430; thence along the "Southeasterly line of said Toyed tract. North 42'30'27" Vert. a distance of 106.34 feet else` the southe•etars, line of American &timel Insurance's tract to the to tioo of the Southwesterly line of a tract conveyed to Laurel D*velopoeot Co., a Nashingtoo corporation, by deed recorded under &cording 90. 761110 -0056; thence along the Southerly line of said Laurel Development Co. Tract. South 51'23 11" Let. • distance of 57.27 feet= chance South 45'56'13" taut • distance of 62.13 feet; thence South 31'32'16" test a distance of 47.23 feet; thence South 76'31'22" test • distance of 72.20 feet; thence South 87'43'37" Luc • distance of 120.00 feet to the true point of beginning; &icnate in the City of 7Lkvilo,'Cooncy of Kim. Scats of Yuhialton. comcipu*d • t,p pap 4 et l page W . 1 1 S 198 _ •G_ 8912010417 •.... If //OW No. a36664 ptsalntal. is !1 That potties of the N.rth.No�t 1/� e� U 2/4 of Section 33. Township as follows/ i00irmi00 at the Northeast ..rn.r of said Northeast 1/4 of the Northwest 1/61 thence North 17•45•3r Vest alas the North lice of said N to the West /margin .f Seat►csrarrdPaartwa7yto0the t=.. Ott fd of beginning, Of themes South 11'39'33' last along said Vest margin a distance of 61.27 feet, Hthence North 07.63•37" Vest a distance of 229.11 feats thence South 62.30.27" W..t. • distance of 693.7 tests pthence South 32'66.03' Last to the South liar of the 64 North..sc 1/4 of the Northeast 1/4 of the Northae.t 1/6 of t said Section 351 thence Westerly along said South line to the last line of S the Northwest 1/6 of the Northwest 1/6 of said Section 351 thence North 01.69'61' Last along said Last U. to the C Northeast corner of said Northwest 1/61 thence South 07.63'37' East sloes the North lie. of siat Of Qt Northwest 1/4 a distaste of 031.10 fast to the true ?o 6D beginning: .•ffShort flaco10. 5397 recorded wader- Lacotdioi No. / boundaries S2, TWITTER WITH an easement for ingress, ogress and utilities 15 feet in width as reserved in Led recorded vadat 1ecording No. 77010506061. . Situate in the City of Tukvi}a. Count? of Ling. State of Washington. tap 7 et 3 N.pe '.4 fel t•� That atlm�26� S.1 but 1/4 of the Southwest 1/6 of Of Tukwila. Township 23 North. Laej. 4 Last V.6L, in the City l�aacc�L Cowry. Washington. &Ittihad a follow' the Southwest � Beginning atthe . tt owner 2 of ..0 L t sit 1/4 of then. north $7'43•37' West • the Louth lit* of said Southeast to the 1/4 .1 the Southwest 1 4. a distance of 411.03 foot Ord tan. continuing Bels .l Southeaster Parba 1 �GND . distance 6Ld north p•4S•ST Vest .Jean said South line. which La parallel fut. ith and f or feet to a ester a . line 17 .anterlin..f • if -foot railroad easement Northwesterly y e•l instrument recorded adder Locording No. 6643373 and the tram o point of beginning, thence north 16.1'33' Sat along said parallel line 02 fat. nors or less. to the centerline of a 40-loot drainage easement granted to the Lot. of Washington by instrument recorded nectar *.cording No. 62333361 thence North $6.3$'32• Vest along said drainage auewmnt centerline 224 fat, more or leas. to the Vest line of the Southeast 1/4 of the Southwest 1/4 of said Section 26i thence Southw South Vat line to tea' thence Last along the South line of said .wbdivi4I.w to the • true pint of beginning. 20CL21¢L VIIV all rights is those eerca/a 13 -foot easements reserved in d.tuweets recorded under Ling County Seeerding 00e. 77010306aS and 7701030666, all situate in the City of Tukwila. County of Ling. State of •Washington. • CITY OF TUKWILA 6200 SOUTHCENTER BOULEVARD, TUEIVILA, WASHINGTON 98188 December 19, 1989 William B. Betlach The Holly Corporation 101 East 26th Street Suite 301 Tacoma, WA 98421 RE: Rainier Ridge E.I.S. Dear Bill, PHONE # ('206,1 433 -1800 Gary L. VanDusen, Mayor The E.I.S. process outlined in your letter of November 27th is essentially correct. Please note that setting the scope of work (Step 4) has been substantially completed and we are now at the point of working together to specify the design alternatives to be evaluated. The alternative actions to be evaluated in the E.I.S. are generally described below: A. The proposed action -- 108 apartment units with buildings extending over the top of slope. B. A less visually prominent project from all identified view points -- The Berry & Berry alternative is too visually prominent from the east and north to fulfil this role. C. No action. I was unable to respond by the December 8th date since your letter did not arrive until December 13th. Please feel free to contact me if you have any questions. I will be out of the office between December 21st through the 27th. Sincerely, Vernon M. Umetsu 00 0 THE HOLLY CORPORATION 101 East 26th Street - Suite 301 • Tacoma, WA 98421 • (206) 627 -5800 November 27, 1989 Vernon Umetsu City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Subject: Summary of Rainier Ridge EIS- Dear Vernon: This letter is intended to summarize my understanding of our phone conversation of November 21, 1989 with regards to the above referenced subject. The proposed action to be addressed in the DEIS will be a 108 unit site plan. The Proponent does have the opportunity if they desire to submit a new site plan totaling this unit count, and is not restricted to the vested 108 unit site plan. STEPS: 1) Proponent submits design alternatives to be addressed in the DEIS to the City. 2) City comments on alternatives, back to Proponent. 3) Proponent resubmits revised alternatives to City. 4) Once City agrees on alternatives, City sets scope of work for EIS consultant. 5) Proponent reviews draft EIS consultant contract. 6) City negotiates contract with EIS consultant. 7) Contract negotiations concluded. Proponent submits to City, at a minimum, check amounting to cost of DEIS. 8) City issues Notice to Proceed to EIS consultant. 9) EIS consultant submits DEIS to City for review. 10) City comments on draft, back to EIS consultant. 11) EIS consultant submits revised DEIS to both City and Proponent for review. 12) City /Proponent discuss DEIS, comments back to EIS consultant. 13) EIS consultant revises draft, to City for approval /start of 30 day public comment period. 14) Comment period expires, all comments received. 15) EIS consultant prepares FEIS. 16) FEIS published, 10 day appeal period. • • • Vernon Umetsu November 27, 1989 Page 2 Please let us know in writing by December 8, 1989 if the above requires clarification. cc: Bruce McCurdy, Southcenter Gateway Associates Dick Chapin, Ferguson & Burdell . RICHARD U. CHAPIN (206) 646-8409 • • L. Rick Beeler Planning Director City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 LAW OFFICES OF Ferguson 8 Burclell KOLL CENTER BELLEVUE 500 - I08TK AVENUE N.E., #2100 BELLEVUE, WASHINGTON 98004 TELEX: 32 -0382 FAX: (206) 454-5719 (206) 453-1711 November 10, 1989 Re: Final EIS Scope for EPIC -33 -88 Rainier Ridge Apartments Coordinated Permits: 89 -1 -DR, and CN -88- 393 -398 Dear Rick: NOV 13 ises I am in receipt of materials furnished by you to Rick Lawrence under cover letter of November 4, 1989. Attached to your cover letter is a copy of a letter of June 8, 1989 from you to William Polk concerning EIS scoping on this project. On page 1 thereof, under "Alternatives to be Evaluated in the DEIS ", item 1 reads: "The proposed action. (Berry & Berry)" The Berry & Berry proposal is the one for 70 units pulled back off the top of the slope. That is not the proposed action. The proposed action is the submittal for 108 units which start at the top of the slope. I am certain you will recall that sometime subsequent to the submittal for the 108 -unit project, you concluded and advised the Applicant that the proposal would require a DS, and an EIS. In order to avoid the time delay involved in 'the preparation of an EIS, an alternative proposal was made, consisting of 70 units pulled off the top of the slope. Thereafter, as I understand it from my clients, you changed your position and advised the Applicant that the 70 -unit proposal would also require an EIS. Thereafter, the Applicant advised you that as long as an EIS was going to be required in any event, the 70 -unit proposal was withdrawn, and the original 108 -unit proposal would constitute our project. Accordingly, it is requested that the scoping notice be revised to make clear that the proposed action is for 108 units per the site plan originally submitted. One of the alternatives which could be evaluated is the 70 -unit Berry & Berry proposal. SEATTLE • BELLEVUE ANCHORAGE 049A0227 L. Rick Beeler November 10, 1989 Page 2 • • If you have any disagreement with me concerning the foregoing, I would appreciate your immediate response. Otherwise we will await a revised scoping notice. RUC:cb cc: Rick Lawrence Bruce McCurdy Sincerely, ,),.-S. -CL., Richard U. Chapin THE HOLLY CORPORATION 101 East 26th Street - Suite 301 • Tacoma, WA 98421 • (206) 627 -5800 November 9, 1989 L. Rick Beeler, Planning Director Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 4 NOV 31989 ) Subject: Rainier Ridge - Final Scoping Notice for EPIC -33 -88 _,near rrt -r. - Beeler: The purpose of this letter is to request an extension in the appeal period for the above referenced subject. This extension is requested for two primary reasons; 1), the statutory requirement regarding appeal period timeframes is unclear, and 2), Vernon Umetsu, our principle contact at the City for this project, will be out of the office until November 20, 1989. Therefore, in light of the above, we request an extension in the appeal period to November 27, 1989. We feel this date will allow both parties to reasonably discuss elements of the Notice prior to expiration of the Notice appeal period. Should the statutory appeal period extend beyond this date, we would opt for the later date. I can be contacted at the above number should you have any questions. ely, ck Lawre ce ce President cc: Bruce McCurdy, Southcenter Gateway Associates THE-IOLLY CORPORATION 101 East 26th Street - Suite 301 • Tacoma, WA 98421 • (206) 627 -5800 NOV 1 31989 November 9, 1989 L. Rick Beeler, Planning Director Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Subject: Rainier Ridge - Final Scoping Notice for EPIC -33 -88 Dear Mr. Beeler: The purpose of this letter is to request an extension in the appeal period for the above referenced subject. This extension is requested for two primary reasons; 1), the statutory requirement regarding appeal period timeframes is unclear, and 2), Vernon Umetsu, our principle contact at the City for this project, will be out of the office until November 20, 1989. Therefore, in light of the above, we request an extension in the appeal period to November 27, 1989. We feel this date will allow both parties to reasonably discuss elements of the Notice prior to expiration of the Notice appeal period. Should the statutory appeal period extend beyond this date, we would opt for the later date. I can be contacted at the above number should you have any questions. ely, ck Lawre ce ce President : Bruce McCurdy, Southcenter Gateway Associates o City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor November 4, 1989 Rick Lawrence The Holly Corporation 101 East 26th Street Suite 301 Tacoma, Washington 98421 RE: Final E.I.S. Scope for EPIC -33 -88 (Rainier Ridge Apts.). Coordinated Permits: 89 -1 -DR, and CN -88 -393 -- 398. Dear Mr. Lawrence, I reviewed your letter of September 22, 1989, the modified project design by Berry and Berry and consulted with the City departments cited. Based on these consultations, I conclude that an environmental impact statement is required with the scope I established on June 8, 1989 (Attachment A) except for the modifications noted. Your specific comments on Earth, Transportation and Utilities are discussed below: Earth The Fraser /Griffin memo you submitted addresses only specific subject areas. For these areas, it calls for at least the level of analysis specified in the EIS scope to be completed during building permit review. I determine that this information is required now during SEPA review because the project impacts are known and measurable. The Valley View Geotechnical and Utilities analysis has been included as Attachment B to illustrate the depth and breadth of analysis expected. I concur with Public Works that further Dames and Moore review is not required at this time. However, such review may be required at a later date should the information requested in the EIS process show it to be appropriate. Transportation and Utilities The analyses of Transportation and Utilities systems continue to be necessary. The next step is for you to accept or appeal this final EIS scoping determination. Once scoping is completed, the agreed upon consultant can be retained. Authorization to proceed with billable work would be given by the City upon your depositing the necessary funds to pay for consultant work: Please inform me in writing of your project intentions. Vernon Umetsu will be able to begin working with the consultant after November 20th. Sincerel L ' Rick Bee er, SEPA Official ATTACHMENTS cc: Bill Betlach Phil Fraser Ron Cameron fI TT�I c City f Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 June 8, 1989 William Polk William Polk Associates 1201 Western Avenue Suite 410 Seattle, WA 98101 RE: E.I.S. Scoping for EPIC 33 -88. Coordinated Permits: 89 -1 -DR, and CN -88 -393 through 398 (Rainier Ridge Apartments). Dear Mr. Polk, I have reviewed the environmental checklist, comments received during the E.I.S. comment period and considered additional information contained in the building permit application. A limited scope E.I.S. is required which addresses the areas of Earth, Air, Water, Noise, Aesthetics, Transportation, and Utilities. The contents of these sections shall clearly evaluate existing conditions, project impacts, mitigating measures and unavoidable adverse impacts in light of the City's comments below. Additional analyses necessary to resolve several issues shall be completed and incorporated into the D.E.I.S. Please note that you will be required to virtually complete geotechnical and structural engineering as part of SEPA review, to assure that the steep slope and soils can support the construction and structures. ALTERNATIVES TO BE EVALUATED IN THE DEIS 1 . The proposed action. (QC92 R Y Y) 2. 3. Some reduction in the number of buildings. Density may or may not be reduced. Schematic concepts to be submitted for City approval. 4. No Action. A description of Project Alternatives 2 and 3 will be provided to the same level of detail as the proposed action including, but not limited to the .following areas: plan view, elevations, cross - sections, and grade and fill plan. Mr. William Polk June 8, 1989 Page 2 • • ELEMENTS OF THE ENVIRONMENT A. Earth Discussion based on the geotechnical reporter and the following revisions to the SEPA checklist: a. Terrain is generally steep slopes with a bench; not rolling. b. Steepest slope is 1.67:1 (60 %); not 2:1 (50 %). c. Boring B -1 shows compressed organic and silt layers at 38 feet. T#is- A geotechnical study and structural engineering analysis will be required to evaluate site stability under existing and proposed conditions. An acceptable engineering safety factor shall be specified and compared with the alternatives This analysis shall include all down slope areas to the Levitz railroad spur and Southcenter Parkway. The City-wi+F have Dames and Moore evaluate all geotechnical /hydrological studies pursuant to the scope in Attachment A. Their evaluation shall be incorporated into the DEIS tf4 WSDOT evaluation of the project alternatives should be included as applicable. This shall include, but not be limited to impacts and mitigating measures surrounding the storm water line running across WSDOT property and into their system. e. Cross - sections primarily running east to west, will be required to show existing and finished grades, and improvements for all alternatives. All retaining wall and rockeries (max. ht. is 4 ft.) shall be shown. Cross - sections shall show the site at a minimum 30 ft. scale. A second set of smaller scale cross- sections shall show the site, existing and finished grades, and alternative improvements in relation to the remaining down slope area to the Levitz spur and Southcenter Parkway. Mr. William Polk • June 8, 1989 Page 3 • f. The highly erodible soils on site (per Geotech. Rept.) indicates a high erosion potential during and after construction. Additional information on erosion control facilities and implementation schedule must be submitted. At a minimum, this shall include evaluating the need for the following development phasing: i. Acquire easement to construct/maintain /repair the storm water line from the property boundary to WSDOT storm water system and construct storm water line with no detention on site to the maximum extent feasible. Any detention facilities required by WSDOT should be constructed down slope on the flats where failure would not be as catastrophic. If on -site detention is feasible, the engineering design safety factor shall be specified and approved by the Public Works Department. Specific recommendations shall not be limited to actual facility requirements such as double walled detention pipes and a regular . monitoring schedule. ii. Build temporary on site storm water construction and erosion control systems. iii. Complete on -site road system including curbing. iv. Complete all upslope improvements with immediate connection of roof drains to storm water system prior to start of down slope construction. This would minimize exposed erodible soils and runoff. An "as built" certified survey by a City selected surveyor on the eastem road curb and building foundation locations shall be required prior to starting work on eastern units. v. Phased construction of down slope units as possible. Phasing and construction practices to be per geotechnical study and as approved by the City. At a minimum, construction phasing will probably prohibit disturbing areas 20 ft. west of the existing eastern slope edge until-all up slope structures and roads are completed. vi. All drainage facilities shall be sized for the 100 year event from the site to a public storm system. h, Ac.c. FUSCIZ /GR.(FFIN H ex- fo rRnl Re-au 2e�ce+rTS (ArT14 CHri CAI T C.) B. Air Quality sNiPcc. 3e- 3-,4 T(S pleb IN E. Evaluate the long term air quality impacts from freeway originated pollutants, if any. If none, substantiate with a discussion. Mr. William Polk June 8, 1989 Page 4 C. Water • a. Storm water runoff will be increased from its current undeveloped condition and diverted into a WSDOT system. WSDOT approval, the storm water line easement, and maintenance provisions must be documented in the E.I.S. b. Assess impacts of up slope water withdrawals due to french drains on building slab settlement in light of organic soils; and on slope stability. c. This parcel is not included in storm water L.I.D. No. 17, as was incorrectly stated in the checklist. d. All storm water control facilities and phasing shall be specified and approved by the Tukwila Public Works Dept. and WSDOT as applicable. D. Noise Summarize the JGL noise study. It may be reasonable to simply incorporate the text discussion. Mitigation should include all recommendations. Also as a mitigation measure, JGL will be later retained by the City to work with the architect to ensure that interior 45 dba Leq levels are achieved. Design shall be to a 40 dBa Leq level to incorporate a 5 dB engineering safety factor. JGL work shall be funded by the applicant. Consultant Note:Engineering safety factor is 3 -5 dB. A 5 dB factor reflects the City accepting the maximum 45 dB noise standard recommended by the EPA. E. Aesthetics View impacts of the two project alternatives will be displayed in an easily readable form. An 11x17 inch fold out may be required for each impact picture. Impacts will be as shown on the attached map. These are generally views at a 6 ft. height from City Hall; So. 180th St. at Southcenter Parkway; Andover Park West and Strander Blvd.; and at the southem end of 53rd Avenue South. F. Transportation a. So. 178 St. is not available as.a year -round street due to the 21% grades. d. Evaluate the need for specific road improvements to mitigate immediate development impacts, the need for a no protest agreement for the formation of an R.I.D. to provide the project's fair share in resolving cumulative transportation impacts, and pedestrian improvements will be based on the following studies: Mr. William Polk • June 8, 1989 Page 5 • Trip generation and distribution of ADT and PM peak hour traffic, and the following LOS intersection analyses: Southcenter Parkway /So. 180th St.; Military Rd. So. /So. 178th St.; Military Rd. So. /So. 188th St. and 1 -5 ramps/So. 188th St. LOS analysis shall be per the latest ITE capacity manual. ii. Vehicle and pedestrian safety analysis of So. 178th St. between the site and Southcenter Parkway. Pedestrian walking routes, school routes, and school and Metro bus accessibility are specific pedestrian safety items to evaluate. iii. Emergency access impairment for fire, police, and ambulance due to weather, 21 % grades, and difficulty to repair failed utility systems when they block access; needs to be identified. iv. Identify King County and WSDOT requirements for new 1 -5 freeway ramps at its intersection with So. 178th St. v. Identify mitigation and funding for safety and capacity impacts. This would include the vehicle, pedestrian, and emergency access; and not necessarily be limited to previously noted mitigating actions on the submitted SEPA checklist (i.e. a turning lane at the project 'entry). vi. A topographic survey by a licensed surveyor and plan view of the site relative to the proposed development shall be provided at a minimum 50 ft. scale. Spot elevations as shot in the field shall be located. G. Utilities a. Certification of water availability from W.D. No. 75 shall be required. Tukwila fire pressure and flow standards shall be satisfied and documented. b. A gravity sewer system is required. The sewer system capacity to satisfy existing demands is marginal. An engineering analysis of availability at the site and sewer system capacity to satisfy project demand shall be conducted. Horton Dennis (Marty Penhallgram) has recently completed an evaluation of sewer capacity in the area. c. Evaluate the need to provide for the impacts of failed sewer and water systems (i.e. by thrust blocks and double walled pipes, and regular maintenance). d. Identify specific improvements to system capacity to satisfy the immediate needs of the project, and any "no protest" L.I.D. agreements which should be executed to ensure the project pays its fair share of cumulative system improvement needs. Mr. William Polk June 8, 1989 Page 6 • • All analyses shall be directed City of Tukwila staff, with consultants approved by the City. Resumes, project examples and references shall be required of all consultants. Additional City consultation with a selected geotechnical consultant and structural engineer to aid in project review shall be paid for by the applicant. Vernon Umetsu of my staff will be available to answer your questions at 433 -1858. Specific technical questions should be resolved directly with the appropriate departments. Si cer Attachments cc: Bruce McCurdy Ron Cameron Gary Kacinski Bill Betlach Catelin Williams Rick Lawrence File Beeler, Planning ire or ,. • • fI `.rrrw1 rrIM DIES & . OORE I'Al:I1 +IiR'II11' N.:., KET!'I -ACic T'_':Cli_ii.. i 'c- ..Ii si' •\ •� rLL, :�:: JVA5FI, �^ nruy 10, 1989 j The City of Tukwila 6200 Southcenter Boulevard l ukwila, Washington 98188 Attention: Mr. Phil Fraser Revised Proposal Review of Cieotechnical Report and Preliminary Plans Rainier Ridge for The City of Tukwila Gentlemen: RECEIVED wy 1 1 1989 TUKWILA PUBUC WORKS Dames & Moore is pleased to present this revised proposal to review the geotechnical reports by Rittenhouse -Zeman & Associates and to review ,the geotechnical and hydrological aspects of the preliminary plans by Tritec Associates, Inc. We understand the purpose of this review is to determine what information is needed to decide that the proposed development will not have a geotechnical failure affecting safety and economics. The documents provided us for review are: I. "Subsurface Exploration and Geotechnical Engineering Report, Proposed Rainier Ridge Apartments, South 178th Street & Interstatae 5, Tukwila, Washington," for Holly Homes Company, 8222 Washington Boulevard S.W., Tacoma, Washington, by Rittenhouse - Ze,uan & Associates, Inc., Bellevue, Waslhngtou, November, 1988. . Letter report, "Summary of Cieotechnical Design Recommendations, Rainier Ridge Apartments: Eastern Buildings, Tukwila, tVashington," for Holly Homes Company, by Rittenhouse -Zeman & Associates, Inc., 21' December 1988. 3. "Supplemental Subsurface Exploration and Geotechnical Engineering Report, Proposed Rainier Ridge Apartments, South 178th Street and Interstate 5, Tukwila, Washington," for Holly Homes Company, by Rittenhouse -Zeman & Associates, Inc., February 1989. 4. Landscape Masterplan by Thomas Rengstort, ASLA, no date. 5. Letter report, "Description of Foundations and First Floor Framing for Buildings A, B and C," by Robert Fossatti Associates, 3 April 1989. 'r•' r. . •rc.rurrrj. i*IDES & MODRE R,:I.F.~. 1,1 \4ITFnI`ARTNEYti1III' The City of Tukwila May 10, 1989 Page 2 6. Site Plan /Building Elevations, 8 sheets, by, William Polk Associates, no date. 7. Letter, "Rainier Ridge Apartments - SEPA Review," to Mr. L. Rick Beeler, Planning Director, City of Tukwila, from Mr. William B. Betlach, Project Manager, Tritec Associates, Inc., 3 April 1989. 8. Letter, "SR 5, MP 153.15 Vic., CS 1767, Status of Rainier Ridge Apartment Complex:" to Mr. William B. Betlach, Tritec AssOeiat¢s, Inc., from Mr. James L. Lutz, WSDOT, 3 April 1989. 9. "Rainier Ridge Apar tments, Noise Study," tp Trite; Associates Inc., Silverdale, WA, frnm JGL Acoustics, loc., Bellevue, WA, 3 April 1989. 16. Permit Application uocuments, L�ty of l ukwrta. Specificully, our scope includes the following: 1. Review the submitted documents for comtileteness and report on itemized deficiencies. 2. Evaluate the Rittenhouse -Zeman & Associates (RZA) site investigations to determine if the investigations Included enough exploratory borings and excavation pits. 3. Review and evaluate the RZA geotechdical and groundwater analysis and design recommendations and conclusions that relate to: • Site Stability • Foundations " Slopes ▪ Retaining walls Rookeries • Site drainage, permanent run -off control, upstream and downstream run -off effects and /or considerations 4. Evaluate acceptability of construction recommendations. • Temporary construction period run -off control ▪ Construction limitations due to weather Met DALES & MOURN The City of Tukwila May 10, 1989 Page 3 :rsrtt : +rnar�rr.ar.r 5. Evaluate suggested /recommended monitoring programs for construction and for design life of project. 6. Evaluate recommended maintenance agreements, particularly for drainage facilities. Also, uny sugguitcd drainage easements and agreements. 7. Provide a written report and recommendations for approval /disapproval of permit based on the geotechnical and hydrological considerations. No independent analyses of existing data will be'performed and we will not acquire any new (site- specific subsurface data. We will complete our review within three weeks after receiving authorization. We will, in submitting our report, identify areas where additional ;ufvi is necessary to complete the Ireview. We will conduct 6U? 1tiVe §ti f &ti66 in accordance, with our standard Schedule of' Charges and billing rates shown on the enclosed Attachments A through C. For the scope outlined above, we !estimate our fee will be between 56,000 to 57,500. The cost breakdown for our services is as follows: (gym 1 12-4 15 I6 7 Pt t► jeel Management/ Billing, etc. Project Engineer/ rrinclpal Man HAM 12 25 6 8 12 Support Time Hours 5 Ketmburslble & Eauloment 50 100 de 50 10 200 1,100 2,600 500 800 1,800 Estimuted Total DES & MOORS n rq; •rr.:. ,. The City of Tukwila May 10, 1989 Page 4 i,, rte VAR rr:lclt� il, It has been a pleasure preparing this proposal for you and we look forward to working with you on this project. If you have any questions, please call us. Anus very truly, DAMES dt MOORE !Orb ns L. Chabra, P.E. Principal Engineer /Assuciate HI.C:kh c. \kuli \suits \props \tukwita.Ita R -1 -72 M -1 • V1 W �MpAC.T • A AC.Ys'S ... L0GATIoU MAP. C-2 L11 VI EL1.� AND brfcFC-%�oN R-H20 kV AV niimar ..c..+..r R-I -12.0 `R -I-12C4 • 14-1-120 C -P 0 0 R -A AGRICULTURAL ❑ SINGLE F MLY RESCENTIAL R+L1D sN3LE awILY RESIDENTIAL R•I -T2 SNGL.E FAMLY RESCENTIAL R-2 TWO FAMILY RFYFNTIAL nnem Am FOUR FA LY RESCSIi1AL n ❑MU. 'TPLE RESCENCE HIGH DEN9TY PMFESSONAL P-0 AND O Cileeixtioco RETAL -2 RHC iICWAL Rms. C -P PLAM!® ASS CENTER INDUSTRIAL PARK Ei MH LIGHT NDUSTRY El2 M- FEA/Y Nd/STRY • RESTRICTED ZONING 2 M-2 CM ArrAcNMWT g - ■/ GeoEngineers Incorporated (206) 881.7900 P.O. Box 6325 2020 124th Ave. N.E. Bellevue. WA 98008 April 25, 1985 Stepan and Associates, Inc. 930 South 336th Street, Suite A Federal Way, Washington 98003 Attention: Mr. Glen McKinney Gentlemen: Consulting Geotechnical Engineers and Geologists We are pleased to submit two copies of our "Report, Geotechnical and Hydrological Studies, Proposed Valley View Estates, Slade Way and 53rd Avenue South, Tukwila, Washington ". This report was developed in two phases. The scope of services for the first phase was outlined in our proposal dated August 9, 1983, and the Phase 1 report was presented on February 17,.1984. This report replaces and supplements our Phase I report. The Phase II services consist of collecting additional data and expanding some of our previous analyses to respond to comments raised during hearings on the Draft Environmental Impact Statement. These services were performed under a confirming agreement dated July 16, 1984 and were expanded by verbal authorization from Mr. Tom Russell, project manager for Puget Western, on several occasions. We have enjoyed working with you on this project and are looking forward to continuing our relationship during the instrumentation installation and monitoring, and construction phases of the project. Should you have any questions or need additional information, please call. GMD:JKT:da File No. 523 -02 cc: Puget Western (8) Attn: Mr. Tom Russell Yours very truly, ineers, Inc. Ja3..K. Tuttle Er.incipal • T A B L E O F CONTENTS Page No. INTRODUCTION 1 SCOPE 2 REVIEW OF SITE HISTORY 4 SITE CONDITIONS 7 SUBSURFACE CONDITIONS 9 GEOHYDROLOGICAL AND SURFACE WATER CONDITIONS 10 STABILITY 12 INTRODUCTION 12 DEEP - SEATED SLIDING 12 SHALLOW- SEATED SLIDING 14 CONCLUSIONS AND RECOMMENDATIONS 16 GENERAL 16 EVALUATION OF I -5 DRAIN SYSTEM 18 SITE DEVELOPMENT 21 STRUCTURAL FILLS AND PAVING 24 RETAINING STRUCTURES 25 FOUNDATION DESIGN 27 INSTRUMENTATION AND MONITORING 28 USE OF THIS REPORT 31 List of Figures Figure No. SITE PLAN 1 HORIZONTAL DRAIN AND WELL SYSTEM 2 EXISTING ON SITE HORIZONTAL DRAIN LAYOUT .3 CROSS SECTION A -A1 4 SCHEMATIC OF PROPOSED INTERCEPTOR DITCH 5 i GeoEngineers Incorporated APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING FIELD EXPLORATIONS LABORATORY TESTING Appendix A Figures UNIFIED SOIL CLASSIFICATION SYSTEM AND KEY TO SAMPLE DATA LOGS OF EXPLORATION APPENDIX B Page No. A -1 A -1 A -1 Figure No. A -1 A -2 Thu A-19 Page No. INSTRUMENTATION AND MONITORING B -1 PIEZOMETRIC LEVELS B -1 INCLINOMETER DATA B -1 TABLE B -1 B -2 TABLE B -2 B -3 TABLE B -3 B -4 TABLE B -4 B -5 APPENDIX C Page No. SLOPE STABILITY ANALYSES C -1 INTRODUCTION C -1 Methodology C -1 Assumptions C -1 Selection Parameters C -3 Results C -3 Additional Analyses C -3 Dynamic Analysis C -4 SHALLOW SLIDING C -4 . Appendix C Figures Figure No. CROSS SECTION FOR STABILITY ANALYSIS C -1 & C -2 ii GeoEngineers Incorporated REPORT GEOTECHNICAL AND HYDROLOGICAL STUDIES PROPOSED VALLEY VIEW ESTATES SLADE WAY AND 53RD AVENUE SOUTH TUKWILA, WASHINGTON FOR DR. H. M. ALLENBACH INTRODUCTION This report presents the results of our geotechnical'and hydrological studies of the site proposed for construction of Valley View Estates. The report replaces and supplements our report dated February 17, 1984. Revisions to the report include additional water level data obtained since issuance of the initial report. We also address, in expanded detail, specific issues raised during review of the Draft Environmental Impact Statement. The site is located adjacent to the west right - of-way for Interstate Highway No. 5 and is bounded on the south by Slade Way and on the west by Slade Way and 53rd Avenue South, as shown on the Site Plan, Figure 1. The proposed development includes construction of 18 six-unit residential structures together with associated roadways, parking areas and utilities. The units will be stepped into the hillside, requiring varying depths of cut. Some cutting and filling will also be required to construct the roadways and parking areas as well as to establish - reasonable grades around the various buildings. Wood frame construction which will result in relatively light foundation loads is planned. The proposed residential property is located within a very large, prehistoric, landslide zone. Also, a substantial portion of the property was involved in the landslide which occurred in 1960 as the result of excavation of borrow material which was used for fill in the Andover Industrial Park. The stability of this and adjacent properties on the southwest portion of the interchange of the freeway with State Route 405 has been improved by the remedial drainage measures which were installed by the Washington State Department of Transportation (WSDOT) during construction of Interstate Highway No. 5. No evidence of recent deep - seated movement was noted during GeoEngineers Incorporated • • our site examinations. The WSDOT drainage facilities include systems of horizontal drains and vertical wells, a number of which exist immediately east of this property. SCOPE The scope of services for these studies was developed. and executed in two phases. Phase I was developed following a meeting on August 2, 1983 of the various parties involved in assembling information for the Environmental Impact Statement for this project. Phase I reflected our assessment of the extent of study which we considered to be appropriate for this project, based on studies made for the 1960 -61 landslide by members of our staff while employed with Dames & Moore and a review of existing surficial site conditions by our firm in 1982. Our proposal for Phase I was submitted in a letter dated August 9, 1983. We received authorization to proceed in September 1983. The purpose of the Phase I services was twofold: 1) to develop pertinent information on soil and ground water conditions for inclusion in the Environ- mental Impact Statement, and 2) to develop further design criteria, as appropriate, for the geotechnical aspects of the project. The Phase I scope of services includes: 1. Exploring subsurface soil and ground water conditions by drilling a series of test borings from which representative soil samples were obtained and in which piezometers were installed to monitor ground water conditions at appropriate levels. 2. Evaluating pertinent physical and engineering characteristics of the soils from the results of laboratory tests. 3. Reviewing information available from the Washington State Department of Transportation on the subsurface drainage system which was installed in the site area during construction of Interstate Highway 5. 4. Defining, to the extent possible, past landslide history of the immediate area. 5. Evaluating the overall stability of the project site for present geotechnical and hydrological conditions. GeoEngineers Incorporated • • 6. Evaluating pertinent design criteria for the geotechnical elements of the project, including stability of cut and fill slopes, design criteria for shallow foundations, retaining structure design criteria, earthwork procedures, and site drainage requirements. In addition, our scope of services for Phase I was expanded to include the installation of a slope indicator casing and obtaining an initial set of readings at Boring F. This installation has been made in an area of past sliding, but lies above the area of planned development so that information from subsequent readings will provide a means of monitoring any movements of the hillside in the area between Slade Way and the planned residential development. The Phase II scope of services was developed following public hearings on the Draft EIS. The scope of services was developed with Mr. Tom Russell, project manager for Puget Western, Inc. and was authorized verbally. The purpose of the Phase II services is to gather additional information on the geohydrologic regime in the hillside and to respond to comments on the Draft EIS. The Phase II scope of services includes: 1. Obtaining an additional set of readings of the piezometers and the slope inclinometer. 2. Flushing out several piezometers installed by others adjacent to the site during investigations for the construction of I -5. 3. Obtaining additional information on the Washington State Department of Transportation well system including sounding the depth and recording the water levels in the wells. 4. Reviewing the Phase I assessment of the geohydrologic regime on the hillside with regard to the additional water level data. 5. Conducting additional static stability analyses to evaluate the stability of the hillside relative to pre- and post -drain installation and to develop criteria for identifying the extent to which water levels in the hillside can safely rise before remedial drainage measures would need to be initiated. 6. Conducting dynamic stability analyses to evaluate the hillside stability under earthquake conditions. 3 GeoEngineers Incorporated • • 7. Expanding our Phase I recommendations for monitoring and instrumen- tation of site stability prior to, during, and following construction. REVIEW OF SITE HISTORY The review of the site history included examining files of the Washington State Department of Transportation in Olympia and various soils reports pertaining to the site specifically and to the adjacent slope stabilization measures accomplished during I -5 construction. The soils reports that were reviewed include: - "Report of Stability Investigation, Borrow Area Slide, 54th Avenue South and South 162nd Street; Tukwila, Washington ", by Dames & Moore, December 1, 1960. "Report of Soils Investigation, Earthslide, South 162nd Street Near 53rd Avenue South, Tukwila, Washington ", by Dames & Moore, June 27, 1961. - "Report on Foundation Investigation, Existing Slide Area, Tukwila Interchange, PSH -1 (SR5) ", by Shannon & Wilson, June 12, 1964. "Summary Report, Slope Stability Investigation, Tukwila Interchange (SR5) ", by Shannon & Wilson, April 14, 1966. - "Summary Report, Soil Conditions and Earth Movements, Vicinity of the Tukwila Interchange ", by Shannon & Wilson, June 21, 1968. - "Geotechnical Design Consultation, Proposed Residential Development, Slade Way and 53rd Avenue South, Tukwila, Washington ", by GeoEngi- neers, May 3, 1982. • The listed reports document a large earthslide that occurred at the site in 1960 as material was being excavated from a borrow area immediately downslope of the site. The extent of the slide is well documented in the 1960 and 1961 reports and is shown in Figure 2. The slide covered the southern two - thirds of the site as well as extending another 200 feet upslope from the western boundary of the site. Measurements during October 1960 indicated that the slide area was moving an average of 0.5 feet per day. Movements continued at a diminished rate in 1961. Slope indicator measurements taken in conjunction with the Dames & Moore studies indicated that movements were occurring in a shear zone 25 4 GeoEngineers Incorporated to 4.0 feet below the ground surface through the central portion of the slide. In addition, the shear zone was indicated to consist of clayey soil underlain by a layer of waterbearing sand. The 1960/61 slide movement had resulted from the combined effect of excavation and the substantial artesian pressures existing in the waterbearing sand layer. The remedial measures considered were based on reducing the hydrostatic pressure within the waterbearing sand layer which appeared to immediately underlie the failure surface. Deep wells as well as horizontal drains and drainage trenches were considered. A series of horizontal drains was installed in the summer of 1961, together with some regrading of the borrow pit area. A plan from the Shannon & Wilson 1964 report showing the locations of the horizontal drains is presented in Figure 3. Altogether, 20 6 -inch- diameter slotted pipe drains with lengths from 100 to 150 feet were installed. Eight of the drains were located along the toe of the roadway fill in the southwest corner of the site, while the remainder were located in the south- central portion of the site. The flow from the drains does not appear to be piped and is probably responsible for some of the existing wet areas at the site. The 1966 and 1968 reports are related to the overall stability of the hillside, both to the north and below this site, as it related to con- struction of the I- 5/SR405 interchange and related roadways. At that time there had been considerable landslide activity not only at the project site but north and northwest along the hillside. Ten to twelve landslides of various dimensions were observed in these areas. The 1968 report shows several recent slide scarps at the project site. With one exception, all of these were less than 200 feet long and were . aligned along the contour; however, one was approximately 700 feet long and was aligned approximately at 45 degrees to the contours in the northern third of the site. This scarp appeared to be the northern boundary of a large slide, possibly the 1960 -61 slide. The proposed remedial measures consisted of an extensive subsurface drainage system of vertical wells tied into horizontal drains and cylinder pile wall retaining structures as shown in Figure 2. In addition, an inter- ceptor drain, shown as the D -3 drain on Figures 2 and 3, was installed. 5 GeoEngineers Incorporated • • • These remedial measures were initiated .by the Washington State Department of Transportation and were subsequently monitored and reported on by Shannon & Wilson. The WSDOT drain system consists of a series of 5- foot - diameter wells tied into horizontal drains originating at the retaining wall along Klickitat Drive, as shown in Figure 2. The wells are located just east of the site. In addition to the large diameter wells, a number of small diameter vertical drains were installed in between the large wells as shown in Figure 2. Based on information in the Shannon & Wilson reports, the horizontal drains consist of 1 71/2- inch - diameter unperforated plastic pipe with 10 -foot- long stainless steel well point tips. In addition, it was recommended that every fifth drain have a section of stainless steel screen at mid- length. We have not located any records that verify whether or not this was done. Information, including elevations, grades and lengths of the WSDOT horizontal drain and vertical well system, is presented in Table. 8-4 in Appendix B. Based on inspection of the wells, it appears that the original pumps are still in place in approximately 70 percent of the wells. The pumps and outlet pipes have been removed in the other wells. The condition of the in -place pumps is not known. Inspection of the outlets of the horizontal drain .system revealed 42 outlets through the cylinder pile retaining wall along Klickitat Drive (see Figure 2). The length and orientation of Any drains in these outlets other than those that lead to the wells is unknown. There may be short horizontal drains to drain immediately behind the wall or•replacement drains to the wells. The extra outlets may also be weepholes to drain the zone behind the wall. Approximately half of the 42 drain outlets, primarily to the north, were dry at the time of our most recent visit (April 12, 1985). Flow through the other weepholes varied from a drip to about one gallon per minute.. There was also. significant flow between the wall panels in two places. At one location, the flow between the panels was estimated to be 4 to 6 gallons per minute. The 1968 Shannon & Wilson report also identifies a system of original test drains that were installed by WSDOT just east of the eastern property line and south of the horizontal drain /vertical well, system (see Figure 2). 6 GeoEngineers Incorporated • •• Our examination of the portions of this drain system still in evidence indicates that they are still at least partially functional. These drains consist of 1 -1/2- inch - diameter PVC pipe. The outlets are connected to buried manifolds, three of which discharge into a drainage gully. The fourth manifold was unable to be located. Approximately 60 percent of the drains were located, of which approximately 20 percent appear to be damaged and in need of repair. Local sloughing and erosion has occurred at the drain outlets in several places. Flows from the three manifold outlets ranged from approximately. 0.25 to 3 gallons per minute. The 1966 Shannon & Wilson report summarizes potential failure modes for the landsliding on the hillside and, like the 1960 and 1961 studies by Dames & Moore, concludes that the mode of failure at the project site is due to the presence of a clayey silt underlain by sands with artesian pressures. The report includes classification and average strength values for the important materials in the hillside. These data were used in our. studies. The Shannon & Wilson report concludes that the I -5 project area slopes (including the area in which the drains and wells are installed) are stable for the static conditions then (1968) existing. They also concluded that the soil materials in the slopes "are unlikely to be significantly affected by seismic activity ". Some evidence of near - surface movement, mostly in the form of shallow creep and flow slides, was noted in our examination of the site prior to preparing our consultation report of May 3, 1982. A recent scarp was observed a short distance east of Slade Way. The scarp is about 200 feet long and varies from about 12 to 20 inches in height. The downslope extent of the slide appears to be limited to the upper portion of the property in which no construction is planned. The slide was estimated to have occurred in 1981 or earlier, based on the extent to which vegetation had reestablished itself along the scarp. SITS CONDITIONS A plan of the site is shown in Figure 1. The site covers approximately 7 acres and is non - uniformly shaped, being bounded on the south and west GeoEngineers Incorporated by Slade Way and on the east by the Interstate Highway No. 5 right -of -way. A sanitary sewer runs along contour through the eastern portion of the site. There is also evidence of the D -3 drain, as shown on Figure 2. The site slopes moderately to the east and northeast with isolated areas becoming moderately steep. A large drainage swale transects the southern portion of the site, resulting in the sewer alignment curving to the west around this swale before swinging to the northeast. There are three benches on the site that appear to be manmade. The presence of the benches may be indicative of remedial grading following previous slide activity. The lowest bench appears to have been constructed during the installation of the sanitary sewer line and essentially follows the sewer alignment to a point where the sewer line crosses the property line at the center of the eastern property line. The ground surface downslope from the sewer bench in the southeast corner of the site is moderately steep. A second bench starts at the southern property line slightly upslope from the sewer line bench and is oriented approximately parallel to the sewer line bench for approximately one -third the length of the site at which point it disappears. The third bench is located in the center of the site and may have been constructed during installation of an old surface drain in this area. Vegetation consists of areas of very dense berry vines, some exceeding 10 feet in height, fairly dense alder groves, scattered evergreen trees, particularly on the western portion of the site, and occasional horsetails, which are indicative of wet ground. Most of the alder trees located on the middle to eastern portion of the site appear to be fairly young, indicating that the site was likely stripped of vegetation following the slide in 1960 -61. Wet surface conditions were observed over much of the site during our field explorations in October 1983. Some of these appear as seeps or springs, possibly originating from the horizontal drains installed in 1961 as shown on Figure 3. A corrugated metal pipe stormwater drain is located at the intersection of Slade Way and South 160th Street and is reported to parallel 53rd South for a short distance before turning east and tying into the D -3 drain. 8 GeoEngineers Incorporated • • The drain was leaking several gallons per minute at the time of our explor- ations. Flow from this drain was apparently being collected by the upper portion of the D -3 drain. SUBSURFACE CONDITIONS Subsurface conditions were explored at the site by drilling 8 borings using a truck- mounted, hollow -stem auger drill rig. The borings were drilled during October 13 to October 21, 1983. Because of wet conditions at the site and relatively steep slopes, a dozer was required to assist the drill rig in moving around the site. An engineer from our staff established the boring locations, maintained logs of the explorations, and obtained relatively undisturbed samples for observation and laboratory testing. The boring locations, as subsequently surveyed by Stepan & Associates, Inc., are shown on Figure 1. Details of the field explorations, along with the boring logs edited to reflect laboratory examination and testing, are presented in Appendix A. Piezometers were installed in all borings except Boring F where an inclinometer casing which will permit future moni- toring of slope movements was installed. Both deep and shallow piezometers were installed in Boring J. Details of the piezometer and inclinometer instrumentation are presented in Appendix B. Subsurface conditions at the site were interpreted from borings in the 1960 and 1961 investigations and from the current drilling program. Three major units were identified at the site as follows: UNIT A: Fill and /or slope debris, probably native to the site and consisting of loose to medium dense silty fine to medium sands. Thickness varies between 5 and 10 feet. UNIT B: Gray silt interbedded with fine to medium sand. The gray silt varies in consistency between medium stiff to very stiff, generally becoming stiffer with depth. The silt has some zones which contain a trace to some clay. Slickensides are present throughout the unit as well as randomly oriented contacts between different gradations of materials. The sand layers appear to vary from 1/8 of an inch to one to two feet in thickness and are generally saturated. 9 GeoEngineers Incorporated • • UNIT C: Gray sandy silty gravel and gray gravelly sand with some silt. Consistency varies from dense to very dense and unit is generally saturated. Unit B generally grades into Unit C. and is separated by a layer of gray fine to medium silty sand in some of the borings. The three units vary significantly both in depth and elevation across the site. As shown in a typical cross section in Figure 4, the units tend to follow the existing topography and slope down to the east. The thickness of the gray silt (Unit B) is less toward the south (25 feet in Boring C) and increases to the north (89 feet in Boring K). The dip of the surface of Unit C is to the northeast and may represent an erosional feature that occurred before deposition of Unit B. GEORYDROLOGICAL AND SURFACE WATER CONDITIONS Two separate and independent hydrologic . regimes exist at the site. The upper regime, existing within Units A and B, is influenced by surface water runoff, seepage from upslope, and direct precipitation. Seepage volumes are small due to the relatively low permeability of these soils. Water pressures in this regime are likely to be hydrostatic. In contrast, the lower regime existing within Unit C is influenced primarily by subsurface ground water flow. The source of water is not known; however, it is likely that it is upslope and to the west or southwest of the site. Water pressures in this regime were artesian at the time of the 1960 -61 slide. The permeability of the soil in the lower regime (Unit C) is significantly higher than the soils in the upper regime and seepage volumes would be expected to be cor- respondingly higher. The original water table at the site has been modified on three occasions in the past 25 years. The first modification occurred after the 1960 -61 slide when several on -site horizontal drains were installed in 1961 on the slope (see Figure 3). These were installed to alleviate the artesian pressures in Unit C and arrest the hillside movements. The second modification of the water table at the site occurred in 1966 when the Washington State Department of Transportation installed a 10 GeoEnglneers Incorporated • • series of large- diameter wells (see Figure 2). These wells were then pumped during construction of a cylinder pile wall along Klickitat Drive to the east of the project site. The .third and most recent modification of the ground water regime occurred near the end of construction of the cylinder pile wall when horizontal drains were drilled to intercept the vertical wells and the pumps in the wells were subsequently switched off. Water levels in the two ground water regimes were measured using the piezometers installed in our borings in•October 1983, three of the piezometers •installed by Shannon & Wilson in 1966 which we were able to locate, and the WSDOT vertical wells. Our piezometers are installed in Unit C, the lower ground water regime, with .the exception of the second piezometer in Boring J which was installed in Unit B, the upper ground water regime. The piezometer levels in our borings were originally measured on November 18, 1983 and subsequently measured on three occasions between November 30, 1984 and March 12, 1985. These data are presented in Table B -1 in Appendix B. Several readings of the Shannon & Wilson piezometers and the WSDOT wells were also taken during this period. These data are presented in Tables-B-2 and B -3 in Appendix B. The Shannon & Wilson piezometers were flushed in March 1985. The piezometric data collected from November 1984 to March 1985 indicate relatively stable water levels in the lower ground water regime (Unit C) at the site. Water level depths range from 29 to 77 feet below the ground surface at the site and 26 to 55 feet as measured in the Shannon & Wilson piezometers east of the site. The water level data from the-WSDOT wells is less consistent and it appears that several wells or horizontal drains are plugged. This is discussed further in the section on "Evaluation of. I -5 Drain System ". In the upper ground water regime (Units A and 8), the water levels are expected.to be.variable, ranging from the ground surface to depths of ten or•more feet, depending largely on local topography, seasonal rainfall, and other factors. In Piezometer J, the water depth has been stable over the last six months at a depth of 9 feet. 11 Incorporated �" STABILITY INTRODUCTION The purpose of the stability analyses is to assess the risk of instability of the hillside. The risk of sliding is related to existing conditions and to the effects of changing water levels in the hillside, as well as to earthquake activity. The analytical procedure consists of evaluating the gravitational force driving the soil downslope and the force of the soil (strength) resisting the sliding. The procedure also takes into account the effects that ground water conditions have on the resisting force. In general, the higher the water levels in the slope the lower the soil strength or resisting force. The risk of slide movement is expressed as a factor of safety which is defined as the ratio of the resisting force divided by the driving force. If the resisting force equals the driving force, the factor of safety is 1 and the risk of sliding is very high, whereas if the resisting force is greater than the driving force, the factor of safety is greater than 1 and the risk of sliding decreases as the factor of safety increases. Generally, slopes having a factor of safety greater than 1.5 are considered to have an acceptably low risk of sliding and are considered to be stable. Stability analyses were conducted to analyze both deep - seated and shallow- seated sliding. Details of the analyses including figures showing the failure surfaces analyzed are presented in Appendix C. A brief description and summary of the results of the analyses is presented below. DEEP- SEATED SLIDING The stability of the hillside was evaluated by considering the different topographic and ground water conditions which existed during the 1960 -61 slide and which exist in March 1985. The alignment of the section judged to be most critical of those analyzed is shown on Figure 1. The first set of analyses was conducted by assuming topographic and water level conditions recorded in 1960 and 1961 and back calculating the soil strength parameters required to yield a factor of safety of 1.0. 12 GeoEngineers Incorporated • • The soil strength parameters so determined are in good agreement and fall within the range of values reported by Dames & Moore and Shannon & Wilson and used in their analyses. The key parameter is the friction angle in the failure zone. The actual values used are as follows: Soil Along Failure Zone GeoEngineers, Inc. Shannon & Wilson, Inc. 0 c Soil Above Failure Zone 0 C 15 .0 25 0 14 0 -- Dames & Moore 14 600 - friction angle in degrees. C - cohesion in psf. 220 700 350 0 The parameters determined in our studies were then used to analyze the slope stability for the March 1985 topographic and water level conditions inasmuch as we judge them to be a reasonable median value of the three sets of parameters reported. The results of these analyses indicate that the factor of safety of the hillside for current conditions is in the range of 1.5 to 1.6 for the sections analyzed. The increase in factor of safety is, in our opinion, primarily due to the decrease in water levels caused by the WSDOT drain system, and represents an acceptable factor of safety in relation to the planned project. The impact of building loads on overall slope stability was also evaluated and found to have a negligible influence on the factor of safety. The possibility of a decrease in the factor of safety with a rise in the water level resulting from deterioration of the drainage system was also evaluated. The results of this evaluation (see Appendix C) indicate that the risk of sliding would become very high, i.e. FS - 1.0, if the water table were to rise an average of 20 feet above the March 1985 levels in the lower artesian aquifer. (See. Tables B -1., B -2 and B -3.) The stability of the hillside was also evaluated for earthquake condi- tions. For this condition, the ground shaking during the earthquake increases the driving force. The seismic increment was approximated in the analysis by . an equivalent static force proportional to a nominal horizontal ground acceleration (pseudo static method). For the project area, a horizontal 13. GeoEngineers Incorporated • ground acceleration of 0.15g, where g is the acceleration due to gravity, was assumed. This value is typically used for seismic design in the Seattle area. It should be noted that the factor of safety calculated using the pseudo static method has a different connotation from that for static loading. Specifically, for the soil conditions which underlie the project site, a factor of safety of 1 or less represents a very high risk of sliding only during the ground shaking period. When the shaking ceases, movements should effectively also cease. This correlates with the observations of movements reported by a local resident upslope of the site after the 1965 earthquake. The actual amount of straining or displacement will depend on specific site and earthquake characteristics as well as the soil and ground water conditions. For the earthquake analysis, the shear plane was considered to have an additional strength component equal to 500 pounds per square foot of cohesion. This additional strength component is representative of the undrained soil conditions which would exist during the short -term cyclic loading. A factor of safety of 1.13 was computed using the indicated earthquake loading and undrained strength parameters. This value is considered, in general practice, to provide a level of risk comparable to a factor of safety of 1.5 for static conditions. SHALLOW - SEATED SLIDING Slope stability due to shallow- seated sliding was evaluated using an empirical /infinite slope approach. This approach is based on reviewing existing slopes at the site and then analyzing different water level conditions, assuming a uniform infinitely long slope of similar material. Slope con- figurations at the site vary from about 2H:1V (horizontal to vertical) to 4H:1V. Perched water levels (upper regime in Units A and B) are variable across the site, ranging from the surface in areas below springs or flow from old horizontal drains to 9 feet (Boring J), or deeper. In some areas, evidence of surficial creep, as expressed by bending in tree trunks as they have grown, on the flatter but wetter slopes, indicates a lesser degree of stability than steeper, well- drained slopes on the site. 14 GeoEngineers Incorporated • • The importance of control of water levels on near - surface stability is illustrated using a 3H :1V continuous slope, the soil strength (0 = 250) assigned to the upper soils in the analysis of deep - seated stability and varying the perched water level. The effect of water level conditions on the factor of safety against sliding (ratio of resisting force to driving force) is shown in the following table. Perched Water Level at ground surface 6 feet below ground surface 12 feet below ground surface Factor of Safety 0.7 1.1 1.4 The recommended final slopes for the site are 3H:1V or flatter. It is our conclusion that the stability of the slopes can be maintained at acceptable levels, provided that adequate drainage of the slopes is accomp- lished. The types of drainage facilities to be installed include an interceptor trench along the western property line, surface drains, a gully French drain, parking area French drains, subsurface wall drains and downspout drains. The extent of each of these facilities which should be installed to develop adequate drainage is discussed subsequently. The actual building loads will have a small favorable effect on the shallow slope stability, as the friction angle of the underlying soil is greater than the overall slope angle and the added vertical load will increase the resisting force more than the driving force will be increased (provided the load is applied slowly so that pore pressures are allowed to dissipate which is assumed to be the case for the type of construction and soils considered). There may be some destabilization of slopes during construction if slopes are oversteepened or adequate shoring is not used. measures including temporary backfilling, buttressing or otherwise toe resistance may have to be initiated. Dynamic loading during an earthquake decreases the stability and may result in movement of any marginally stable slopes around the Remedial increasing of slopes perimeter of the project. As described previously, the sliding should be limited to the duration of the earthquake. Resistance to sliding of individual structures requires analysis on a site - specific basis. This analysis should 15 GeoEngineers Incorporated • • be conducted by GeoEngineers, Inc. and the appropriate corrective measures recommended for inclusion in the design during the preparation of the final plans. CONCLUSIONS AND RECOMMENDATIONS GENERAL We conclude that development of the property as planned is feasible providing that maintenance of the WSDOT drain systems to the level required to maintain or improve present performance is accomplished and that the recommended near - surface drainage measures are accomplished as subsequently discussed on pages 22 and 23. Development of the site will be difficult due to the marginal stability and saturation of the .near - surface soils. Close coordination between the earthwork contractor and the engineer will be required to see that our recommendations are diligently followed, as subsequently discussed on page 22. There are two principal mechanisms of slope instability which could affect the property. These include deep- seated sliding in a zone of soil from 30 to 50 feet below the surface and surficial sliding in the upper unit of soil, generally extending to a depth of about 10 to 12 feet below the present ground surface. The potential for movement of the hillside in the deeper zone of soils is largely controlled by the continued satisfactory performance of the vertical well /horizontal drain system which was installed during construction of Interstate Highway S. It is also controlled to a lesser degree by the "Original Test Drains" which were installed south of the vertical well /hori- zontal drain system. From our review of available information, it appears that the overall site stability in the approximately 20 years since these drains have been constructed has been good and that the drainage system continues to be generally effective in preventing deep - seated movements. It is of prime importance, however, that both of the WSDOT drain systems remain fully operational. If the drainage systems should deteriorate so that artesian pressures can again increase beneath the hillside, the risk of deep - seated and extensive earth movements can be expected to significantly increase. 16 GeoEngineers Incorporated • • The second mechanism of shallow - seated movements is largely affected by surface runoff and near - surface infiltration of rainfall and runoff from higher ground. Based on the approximately 200 - foot -long scarp that was observed in 1982 and considered to be indicative of recent movement, it is evident that this potential for surficial movements is still relatively high in the southern portion of the property. We recommend that surface and near - surface drainage on the site be improved by constructing an interceptor ditch along the westerly limits of the property adjacent to Slade Way, together with installation of various drainage facilities in connection with site grading and building construction which are discussed subsequently. The piezometers and slope indicator which have been installed as a part of this investigation form the basic components of an instrumentation program to monitor long -term behavior of the property. We recommend that this instrumentation program be expanded prior to construction. Additional slope inclinometers and piezometers should be installed at locations where they can be protected and remain functional, both during and following construction. A series of hubs should be installed above areas where cuts are planned. The hubs should be initialized (surveyed in) immediately and monitored on a regular basis thereafter. The system of piezometers and the inclinometer currently in place should also be maintained and monitored on a regular basis. Some of the new piezometers may have to be located to replace existing piezometers which may be lost in construction activities. A long -term monitoring program to be accomplished under the direction of (or by) our firm is recommended. We consider such a program essential to detect any changes in effectiveness of the WSDOT and on -site drainage systems so that early remedial action can be taken if needed. The extent of the recommended instrumentation program is described in a subsequent section. Earthwork on this property will be very difficult. We recommend that site grading be undertaken during the late summer -early fall months when the least amount of rainfall can be expected and surface runoff and seepage in the upper soil units should be diminished. Depending upon the overall construction schedule for the project, it may not be possible to accomplish all earthwork and drainage- related activities as well as foundation construction 17 GeoEngineers Incorporated • • in a single dry season. Therefore, we strongly recommend that construction activities be scheduled so that site grading, drainage installation and surface stabilization, if not final paving, are completed in any given area within a single construction season. Construction should also be phased, as described subsequently, to minimize the impact in any one area. No area should be left partially graded or without proper. surface drainage, as this may endanger the near - surface stability of that portion of the site if left through the wet seasons. Several of the planned structures are shown located above the existing sewer (see Figure 1). We understand that the sewer alignment may be changed so that it no longer is located below the structures. However, special foundation preparation procedures, as .described on page 25, will be necessary along the sewer alignment to provide uniform bearing support for the structures. A major drainage way intersects the site in an east -west direction through the center of the site. It is important to maintain provisions for drainage along this gully alignment. Accordingly, we recommend that a French drain be installed along the base of the gully as shown in Figure 1 before any filling is accomplished. EVALUATION OF I -5 DRAIN SYSTEM The operational life of horizontal drains is not well known. Depending on the soil type into which the drain is installed, the installation method and other factors, drains may operate satisfactorily for many years. However, drains are also known to silt up or clog due to corrosion or algae and bacterial growths within the slotted sections of pipe. This can result in major, if not total, loss of operating effectiveness after a few years. There appear to be no data available to. assess periodic changes in performance of the WSDOT drain systems over the last few years. However, there are records of the water levels during the period December 1966 to June 1968 for several piezometers located immediately east of the site. There are also.records of our piezometers from November. 1983 through the present, and recent records of the water levels in three Shannon & Wilson piezometers 18 GeoEngineers Incorporated and in the WSDOT wells (see Tables 8 -1 through B -3). Although the data are seasonal and precipitation varies on an annual basis, we believe that there is a sufficient data base on which to evaluate the effectiveness and degradation of the WSDOT drainage system. The locations of the.piezometers for which data are available during the period December 1966 to June 1968 are shown in Figure 2. The piezometric elevations before and after drain installation during this period as well as the March 1985 readings are tabulated below: PIEZOMETRIC ELEVATIONS (FEET) IN SHANNON & WILSON PIEZOMETERS PRE AND POST 1-5 DRAIN SYSTEM INSTALLATION Pre Drain Post Drain Piezo- Tip Water Water Elevation meter Elevation Elevation Dec. 66 Oct. 67 June 68 March 85 LA 85 155 101 92 90 93 1B 100 115 109 97 100 111 19 52 149 111 111 122 N/L 232 49 72 65 60 77 N/L 1 80 162 103 102 110 139 2 86 153 130 122 123 N/L 3A 90 137 105 99 120 N/L N/L - Not able to be located. The tabulated data indicate that, with the exception of Piezometer 232, the piezometric surface was lowered between 15 and 65 feet approximately 3 years after installation. Since that time (June 1968) to the present, the water levels in the three Shannon & Wilson piezometers which we were able to locate indicate a rise of 3, 11 and 29 feet in Piezometers 1A,. 1B, and 1, respectively. This indicates some degradation in the drain system; however, it may be related in part to the fact that the drains have not yet been cleaned out by WSDOT in 1985 (as of April). A similar comparison may be made of the water levels in Borings DM -1 and DM -3 from the Dames & Moore June 1961 report and Borings D and G in this study just inside the east property line of the site. This comparison is based on water levels at the time of the slide and at the present (March 19 GeoEngineers Incorporated • • 1985) time. Borings DM -1 and DM -3 both indicated artesian conditions shortly after boring completion. Borings D and G indicate water levels approximately 56 and 77 feet below the surface, which represents a substantial reduction in water level in this area. Finally, a comparison may be made between the existing water levels in the vertical wells and the elevations at which the horizontal drains intersect the wells. If the system is operating effectively, the water levels in the wells should be 1 to 2 feet higher (to account for head loss in the horizontal drain) than the intercept elevations. Comparison of the data in Tables B -3 and B -4 in Appendix B indicates that only a few wells, 19 and 22, 23 and 24, are operating effectively. The water levels in the other wells are generally on the order of 20 feet higher, and Wells 1, 2 and 3 up to 70 feet higher than the levels of the horizontal drains at the wells. The excess head in the wells may indicate clogging of the drains (increased head required to obtain flow), or it may simply indicate total clogging of the horizontal drains and reduced flow by alternate paths. In addition, Wells 1, 2 and 3 are not consistent with Wells 4 and 5, and Shannon & Wilson Piezometers 1, IA and 1B. It appears that, with the exception of the four wells noted, all of the horizontal drains and /or vertical wells are blocked to some degree. At this time (April 1985), it appears that the WSDOT drains have not been cleaned out for some time, based on the vegetative growth at the outlets. It is likely that maintenance of the drain system will affect the water levels in the wells and thus influence the conclusions to be drawn from the existing available data. However, in spite of the indicated reduced performance of the WSDOT drain system, the water levels at the site are still significantly below the levels that existed at the time of the slide and the system is, in our opinion, still effective in maintaining the water level in Unit C low enough for adequate (F.S. -1.6) deep- seated stability of the hillside. However, we believe that_the stability of the project site is primarily dependent on the continued effective operation of the WSDOT drain system. It is improbable, in our opinion, that the water levels at the site will rise to critical levels in a short period of time (that is, in days or weeks) but, rather, over a period of months. With monitoring 20 GeoEngineers Incorporated • • at regular intervals, changes in water levels can be detected and appropriate remedial measures may be implemented. The multiple well groups and horizontal drains provide a redundancy to the system. Also, some of the flow appears to have found other paths, possibly along the outsides of some drains, as evidenced by the flow through the panels at the retaining wall. We believe that it is essential that WSDOT expend effort to flush the horizontal drains and restore the effectiveness of the wells. If nothing is done, the drain system will continue to deteriorate, probably accelerating with time; however, if the drains are flushed and the wells cleaned and redeveloped if necessary, the system should continue to be effective for many years. Given the importance of the WSDOT drain systems on the stability of the project site, we recommend that the following repair work and maintenance procedures be implemented by WSDOT as soon as possible. o Clean out and flush the horizontal drains. o Clean out, flush and develop, if necessary, the 24 vertical wells. o Extract the pumps after flushing. (It is likely the pumps are silted in and may not be able to be extracted without flushing.) o Sound the depths of the wells. o Secure the top plates on the wells to prevent extraneous matter from being thrown into the wells. o Repair the "original test drain" system. o Locate and document the manifold outlets for the original test drains. o Monitor the flows from both systems of horizontal drains, as well as the piezometer levels, as discussed in the section on "Monitoring." SITE DEVELOPMENT • The sequence of operations required to develop the site is critical to the successful completion of the project. In view of this condition, we have developed a general sequence for site development with regard to installation of instrumentation, drainage, site clearing and.grading, and construction. Only minor deviations should be permitted from this sequence and then only with the approval of the engineer. 21 GeoEngineers Incorporated • • The recommended site development sequence is as follows: 1. Install additional instrumentation at least two months in advance of construction, and preferably as soon as possible, to establish the preconstruction data base. (See section on Instrumentation and Monitoring for details.) Monitor instrumentation on a regular basis, to be specified at the time of installation, before, during and after construction. 2. Construct interceptor trench along west property line (see later details in this section), install temporary drainage ditches in construction -free upslope areas, and install temporary erosion control measures to pick up concentrated surface water flow, locate and tightline appropriate on -site horizontal drains. 3. Establish access road, accomplish general site clearing, install gully French drain and accomplish general site grading. 4.' Perform individual structure grading on a phased basis. Alternate building areas should be graded and with the number of sites prepared limited to the number for which foundation, wall construction and backfilling can be completed during the dry season. The approximate location of the.interceptor trench is shown on Figure 1. The trench should be approximately 2 feet wide and not less than 7 feet deep. It should preferably extend to the top of the gray silt which varied between 7 and 12_ feet in the three closest borings. The trench should be lined with a monofilament filter fabric such as Mirafi 140N, with not less than 2 feet of overlap of adjacent sections of the fabric. A 6 -inch smooth -wall perforated pipe should be fully bedded in a well - graded sand or clean gravel at the bottom of the trench. The remaining trench backfill should be clean, free - draining sand and gravel. The filter fabric should cover the free - draining fill with a fabric overlap of 12 inches below the surface and be covered with the silty native soil. A detail of the interceptor trench is shown in Figure 5. The approximate location of the gully French drain is shown in Figure 1. The drain should be installed from the downstream end working up the existing gully. The gully should be cleaned out of all organic material and debris for a width of at least 8 feet and a 3- foot -thick blanket of graded sand 22 GeoEngineers Incorporated • • and gravel filter placed in the gully. A smooth -wall, 8- inch - diameter perforated PVC pipe should be placed in a 12- inch -deep trench in the filter material and then covered with an additional 2 feet of the filter material. The top of the filter material should be at least 4 feet wide. The filter material should then be covered with filter fabric, as previously specified for the interceptor drain. Fill may then be placed in level lifts on either side of, and above, the filter material. We recommend that permanent French drains be installed along the upslope sides of all parking areas. These drains should be at least 5 feet below finished grades and should consist of perforated pipe fully bedded in a graded sand filter or in clean gravel which is, in turn, enclosed in a filter fabric envelope. The filter fabric should be installed with overlaps in the same manner as described above for the interceptor trench. The remaining trench backfill should consist of clean, free - draining sand and gravel. A similar drain should be installed in any wet areas to the west of the building unit. Flow from these drains may be combined with flow from footing drains and downspouts for disposal in a storm drain system; however, the design of connecting pipes should be such to prevent backflow into sections of perforated pipe. We anticipate no impact om the WSDOT drain system from the proposed development if surface runoff is collected and routed off-site and surface water infiltration is minimized as recommended above. This conclusion is based on the fact that the WSDOT system services the lower aquifer and the barrier of lower permeability soils afforded by Unit B essentially precludes continuity between the upper and lower ground water regimes at the site. See Section on "GEOHYDROLOGICAL AND SURFACE WATER CONDITIONS" in this report. The ability to use the on -site soils for fill is expected to be limited. We anticipate that the soils in their natural state will be above optimum moisture for adequate compaction. In order to use these soils, drying will be necessary. Also, we recommend that only clean granular soils be used for fill behind retaining structures. While careful segregation of 23 GeoEngineers Incorporated • • the natural soils during excavation may provide some suitable backfill, we anticipate that much of the backfill behind the walls and for any areas of structural fill will have to be imported. Stockpiling should be limited as much as practical on the site to minimize potential impacts on slope stability and erosion. As noted, most of the on -site soil to be excavated will be unsuitable for backfill and should be immediately removed from the site: The earthwork should be sequenced to limit the size of. any stockpiles. If stockpiles are required, they should be placed at the north end of the site. The site and height of the stockpiles should be determined on a specific basis as construction progresses and in coordination with our field representative. We recommend that temporary cut slopes be made no steeper than approxi- mately 1- 1 /2H:1V (horizontal to vertical) and be limited to 15 feet in height. The stability of these cut slopes will be relatively low. Our analyses indicate that the factor of safety under static, drained conditions - will be on the order of 1.2 to 1.3,.assuming some short -term cohesion. Some sloughing or localized sliding should be anticipated, particularly where zones of seepage are encountered. When the,excavations are made for the various buildings, we recommend that the construction be sequenced so that alternate building sites are excavated (for example, Sites 3, 5, 7, 9, etc.); retaining walls built and adequately braced, perimeter drainage installed, and backfill placed before beginning excavation for the intermediate buildings. Permanent-cut or fill elopes should be eetablished.at no steeper than 3H:1V. Slopes should be seeded as soon, as practical. Localized, seeps which are not intercepted by the general drainage facilities may have to be drained and /or excavated and backfilled with gravel or crushed rock to resist erosion damage to elopes. STRUCTURAL FILLS AND PAVING All structural fill should be placed in relatively thin (8 to 10 inches) layers and uniformly compacted. Backfill against retaining walls, particularly those in the structures, should not .be overcompacted. A compaction of 24 GeoEngineers Incorporated 90 to 92 percent of the maximum dry density determined by ASTM D -1557 should be achieved. Fill beneath paved areas or forming slopes should be compacted to 95 percent of maximum density. We understand that access roadways and parking areas will be paved with asphaltic concrete. Prior to placing base course material, we recommend that the exposed subgrade be thoroughly proofrolled. Any soft, loose or wet areas should be excavated and replaced with clean granular fill if the natural soils cannot be satisfactorily recompacted. Based on the existing surficial wet conditions, it should be expected that overexcavation and replacement of on -site soils with imported granular fill will be necessary over much of the roadway and the parking area. Overexcavation of 12 to 18 inches may be necessary for roadways and parking areas to establish a stable subgrade. All fill placed below subgrade level should be compacted to at least 92 percent of maximum dry density (ASTM D- 1557). A pavement section of 4 -1/2 inches of clean pit run subbase, 1 -1/2 inches of crushed rock base and 2 inches of asphaltic concrete should be used. The extent of overexcavation and replacement of backfill along the existing sewer in areas to be occupied by buildings should be verified by examination during construction. As a worst case condition, the following may be necessary. Fill used to replace material excavated from the sewer line trenches should consist of clean granular soil. The existing backfill should be excavated from beneath the full building area and beyond for a distance of 4 feet on both sides to a depth of at least 5 feet below the bottom of the footing or to the top of the pipe, whichever is more shallow. The first foot of backfill over the pipe should be compacted to about 92 percent of maximum dry density and the remainder to 95 percent. RETAINING STRUCTURES Retaining structures will be required for all of the buildings based on present plans. The units will be stepped into the hillside so that each section of retaining wall will be no more than one story high. The setback between walls is expected to be 15 feet or more. In addition, retention of cut slopes and fill embankments will be required along portions of the parking areas and near Unit Nos. 1 and 2. 25 GeoEngineers Incorporated We recommend that lateral pressures on the basement walls be determined using an equivalent fluid density of 35 pounds per cubic foot (pcf) times the height of the wall in feet. This value applies only if clean, lightly compacted granular backfill is used against the walls and if a perforated drain is installed along the base of the wall to prevent the buildup of hydrostatic pressure. This value also applies only where the ground surface behind the wall is level for a distance equal to the height of the wall. If a sloping ground surface exists closer to the wall, this value may have to be increased. Retaining structures along the parking area and elsewhere outside of the buildings could consist of gabion basket walls, reinforced earth structures, or conventional poured concrete walls. We recommend against the use of rockeries except possibly for protection of low (less than 5 feet) cuts into natural soils. Rockeries should not be used to retain fill embankments. Where backfill behind the walls is level, lateral pressures may be determined using an equivalent fluid density of 35 pcf times the height of the wall in feet. Where the surface slopes upward behind the wall, an increased lateral pressure must be used. If a backslope of 3H:1V exists, we recommend that the lateral pressures be determined using an equivalent fluid density of 60 pcf times the height of the wall in feet. We should review design criteria for other backslope configurations. Drainage of the backfill as well as cut slopes behind these retaining structures is critical to their stability. The lateral pressure design criteria given above is based on drained conditions. For solid structures, such as a poured wall, a zone of clean backfill and a perforated drain should be installed. If gabion basket walls are used, we recommend that filter fabric be placed beneath and behind the baskets to prevent the retained soils from washing into the relatively open work gabion rock. A perforated base drain located immediately behind the baskets is also recommended for gabion installations. Resistance to lateral loads on retaining structures may be developed by passive pressures and base friction. We recommend that passive pressures be determined using an equivalent fluid density of 200 pounds per cubic 26 GeoEngineers Incorporated • • foot. Base frictional resistance can be determined using a factor of 0.3 times the vertical downward component of long -term loading. These values incorporate a factor of safety of about 1.3. FOUNDATION DESIGN We recommend that the lowest floor grade of each structure be established at an elevation such that a shallow foundation system will bear directly on natural soils below the topsoil layer. We recommend specifically against supporting structures on a combination of cut and fill. It may be necessary to overexcavate and replace some of the native materials if soft, wet conditions are encountered during construction. This will. probably occur all along the sewer line, as previously discussed. Overexcavation /replacement will be satisfactory providing that any fill which is placed does not extend above the original ground surface elevation. We suggest the use of a foundation 'system consisting of a thickened slab system that will provide more rigidity and resistance to slight differential movements across a structure than that which would be provided by continuous wall footings and a slab -on- grade system. The foundation system should consist of thickened edges around the perimeter of the slab and thickened sections beneath bearing walls within the buildings. The thickened slab system should have continuous reinforcing consisting of reinforcing bar rather than steel mesh. The thickened edge sections should extend at least 18 inches below lowest adjacent finished grade and should have a base width of at least 18 inches. The thickened edge portion of this foundation system may be proportioned using a bearing value of 2,000 pounds per square foot. This value applies to the total of all design loads including wind or seismic, but excluding the weight of the footing and any overlying backfill. Care must be taken in preparing the subgrade for the thickened. slab foundation system to avoid disturbance to the bearing materials. Any seepage which is encountered should be' collected and diverted from the building area. The prepared bearing surfaces should be examined by one of our staff to determine that suitable preparation has been accomplished. It may be necessary to move and replace soft, wet or otherwise disturbed soils and to install localized drainage facilities to handle any seepage within the building area proper. Any soft soil should be replaced with clean granular • 27 GeoEngineers Incorporated • • fill compacted to 95 percent of the maximum dry density. We recommend that the bearing surface be protected from disturbance during reinforcing steel placement and concrete pouring by placing a 4- inch -thick layer of clean sand or sand and gravel compacted to a moderately dense state. Over - compaction should be avoided to prevent pumping if the subgrade soils are wet. We recommend that foundation drains be installed along the outside of the thickened edge sections of the foundation system. These drains, together with the drains for the retaining wall sections of the buildings, should be connected to tight drain lines along the east property lines so.that flow can be conducted off -site for disposal in a means which will not adversely affect the stability either of this site or the hillside to the east. Settlement of the foundation system designed and installed as recommended above is expected to be relatively small, probably on the order of 1/2 to 3/4 of an inch. Some differential settlement may occur across units because of the differences of relief of overburden pressure resulting from the varying depths of excavation to establish lowest floor grade levels. INSTRNTATION AND MONITORING The purpose of the instrumentation program and long -term monitoring at the site is to establish base line data for the performance of the horizontal drain system and, hence, to set up an early warning system if the water levels in the slope start to rise. The instrumentation program which we envision as being appropriate includes piezometers located in areas where they will not be damaged by site grading and construction activities, a network of inclinometers to monitor any hillside movement, survey stakes on slopes which are regraded or which have cuts made at the toe of the slope,. and benchmarks established on building foundations as they are con- structed. We recommend installation of at least 6 additional inclinometers, 4 along the easterly boundary. of the project site and 2 along the upper portion of the site, one to the north and one to the south of Inclinometer F. These inclinometers will be installed to function as piezometers as well. 28 GeoEngineers Incorporated The piezometers and inclinometers should be installed at least two months prior to, and preferably as soon as possible, to start obtaining baseline data. The number of additional piezometers installed may vary, depending on how many of the existing ones can be saved. It appears' probable that 4 or 5 of the existing piezometers will be lost (D, G, H, J, and K). We recommend installation of 6 to 10 shallow piezometers (i.e., to depths of approximately 20 to 25 feet each) to monitor water levels in the upper soil strata and 3 or 4 additional deep piezometers to supplement the piezometeic data developed from the inclinometers. The shallow piezometers will monitor the effectiveness of the westerly interceptor drain and other site drainage facilities. In addition to the long - term instrumentation, slope monitoring stakes should be installed in areas where grading involves cuts into the near - surface soils. These should consist of one or more rows of stakes on.20- to,40 -foot centers from which elevation and alignment records can be maintained to determine whether or not any movements occur in the surficial soils. If any movements are detected, remedial measures will be able to be undertaken promptly. As building foundations are placed, permanent reference points should be established at least on the four corners of each building and the elevations recorded. Future elevation readings of these points will then provide a basis for determining any elevation changes which may occur due to foundation settlements or hillside movements. If hillside movements should occur, they would also be reflected in the inclinometer readings. We recommend that the monitoring program initially require that inclino- meters and piezometers be monitored monthly during construction, bi- monthly between construction seasons and twice a year, in February and August, after completion of the project. More frequent monitoring may be. required, depending on the weather. Slope monitoring stakes should be surveyed on an every- other -day basis while grading activities are underway in the immediate area and monthly during periods of construction until project completion. .It is anticipated that slope stake systems will be lost in final landscaping. 29 GeoEngineers Incorporated Benchmarks on building foundations should be initialized as soon as they are set and read once when each building unit is about 50 percent complete, once upon completion, and annually thereafter. .A detailed action ,plan should be prepared so that it can be promptly implemented in the event of significant changes in water levels or indications of slope movement. The plan should include trigger levels for the inclinometers and piezometers, and specific actions by responsible parties should be established. We recommend that an overall rise. in water level of ten (10) feet in the lower aquifer (Unit C), as measured by the on -site piezometers, be taken as a "trigger" level for remedial action. Other trigger levels related to the WSDOT drain systems should be established once they have been cleaned out and are working properly. Trigger levels for the inclinometers should be based on an increase in displacement of more than 0.2 inches per year. The action plan should consist of the following: 1: Notifying our firm immediately. 2. Analysis of the data by our firm to establish.the probable cause of the changed conditions at the site. 3. Developing recommendations by our firm for obtaining additional information if necessary and to implement the necessary remedial measures. These recommendations may include: o Obtaining additional information such as surveying the settlement hubs at the site. o Increasing the monitoring frequency. o Maintenance or restoration of the on -site drainage or WSDOT drain systems. o Installation of new horizontal drains on or off site (WSDOT right -of -way). o Pumping the vertical wells in the WSDOT system. o Implementing localized slope stabilization measures. It should be kept in mind that modifications to the number, locations, and, possibly, types of instrumentation as well as modification in the .frequency of monitoring may be appropriate as project construction progresses. 30 OeoEngineers Incorporated • • For this reason, it is imperative that GeoEngineers have a continuing parti- cipation on the project to coordinate installation of the instrumentation, to recommend changed locations or additional points, to monitor the instrumen- tation, and to interpret the data and advise on the performance of the hillside and recommend what, if any, remedial measures may be appropriate. USE OF THIS REPORT We have prepared this report for use by Dr. H.M. Allenbach and members of the design team. This report should be provided to prospective contractors for their bidding or estimating purposes. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. As noted previously, we have used data developed by our firm as well as by others at widely spaced locations. If there are changes in the loads, grades, location, configuration or type of construction planned from that which we have been provided, the conclusions and recommendations presented may not be applicable. If design changes are made, we request that we be given the opportunity to review our conclusions and recommendations and to provide a written modification or verification. When the design has been completed, we recommend that the appropriate construction drawings and specifications be reviewed by our firm to see that our recommendations have been interpreted and implemented as intended. The earthwork and site preparation activities are of critical importance to the success of this project. GeoEngineers, Inc. must be involved in the construction monitoring and field to see that our recommendations are properly interpreted and implemented. If we are not involved in the con- struction phase of the project, we disclaim any liability for the manner in which the construction is accomplished or the results thereafter. 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 specifi- cally described in our report for consideration in design. There are probable variations in subsurface conditions between the explorations and also with time. A contingency for unanticipated conditions should be included in the budget and schedule. The construction monitoring, 31 GeoEngineers Incorporated testing and consultation by our firm will provide the opportunity 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 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 warranty, express or implied, should be understood The conclusions and recommendations in in their entirety. If there are any questions concerning this can provide additional services, please call. this report should be applied report or if we • ; GMD:JKT:da File No. 523 -02 April 25, 1985 .Respectfully submitted, GeoEngineers, or ..n M. Denby Se. Engineer J . Tuttle incipal 32 GeoEnglneers Incorporated PROPOSED INTERCEPTOR TRENCH PROPOSED FRENCH DRAIN PARKING KIILkl NCL: UKAWIN�, LNIIIILU "VALI LY VILW LSTAILS" I 12" DIAMETER DUCTILE IRON SEWER LINE NOTE: PROPOSED INTERCEPTOR TRENCH TO BE LOCATED'IN THE FIELD. TRENCH TO BE ALIGNED ALONG CONTOUR AND DRAIN FROM NORTH TO SOUTH. PROPOSED FRENCH DRAIN TO BE LOCATED IN FIELD IN EXISTING DRAINAGE GULLY. • 0 EXPLANATION: BORING LOCATION AND LETTER DESIGNATION OM-1 ® UAMCS E MOOR1. INVLSIIGATION 1461 0 80 SCALt IN ILL! FlLUKE 1 1 FIGURE 3 trrtb'1..R D Reference: Drawing entitled "Plan of Slide Area with Reconnaissance Data and Proposed Drainage" by Shannon 6 Wilson, dated June, :964. • Legend: Marsh Areas with Surface Seepage OO Seepage Zones Horizontal Drains Installed by Others 0.4 gpa Fiuw Measured May 12, 1964 Subdrains to he Installed Under Existing Contract ® .Slope_ Indicator Installed by Shannon S Wilson, Inc. In June, 1964 0 Drill Hole Made by Shannon 6 Wilson in May —June, :964 Q Observation Well Installed by the State ® Slope Indicator Installed by the State e Boring Made by Dames 6 Moore, Aprt1111/ 1961 0 50 100 150 L 1 1 1 Scale In Feet GeoEngineers Inc. f*ISTIN(, (IN SITI- rI6URL 4 A 240 200- 120-, PROPERTY LINE . ESTIMATED PERCHED WATER TABLE z 0 0 W z r wl al 0 a 0 z z a m'0 O WATER TABLE IN UNIT C UNIT C UNIT A GRAY SILTY SAND AND SANDY SILT (COLLUVIUM AND SLOPE DEBRIS) UNIT B GRAY'SILT WITH INTERBEDDED WET SILTY SAND TO SAND LAYERS; SLICKENSIDES TOWARDS BASE OF UNIT. UNIT C GRAY SAND AND GRAVEL INTERBEDDED WITH SILT LAYERS; WET. 1 A -240 - 200 -160 - 120 -au ELEVATION IN FEET HOk1ZUNTAL 5CALL: 1" - 40' I.A I UM: (. 1 1 Y ul 1 uI.W 11 %1 GeoEngineers Inc. . 1 in.. • • ►.�Z"7 -OL HK1'' WJ `I•L85 FIGURE 5 WELL GRADED SAND OR CLEAN GRAVEL BACKFILL NON -WOVEN FILTER FABRIC MINIMUM WIDTH =2' 6" PERFORATED PIPE MINIMUM DEPTH =7' GeoEngineers Inc. SCHEMATIC OF PROPOSED INTERCEPTOR DITCH A P P E N D I X A FIRT,D EXPLORATIONS AND LABORATORY TESTING FIELD EXPLORATIONS Subsurface soil and ground water conditions at the site were explored by drilling 8 borings at the locations shown on the Site Plan, Figure 1. The borings were generally terminated in the waterbearing sand and gravel layer. Total lineal footage was 572 feet. The borings were drilled using a truck - mounted, 4 -inch inside diameter, hollow -stem auger drill rig. Observation wells consisting of 1/2 -inch PVC pipe with a slotted tip were installed in all borings, except Boring F, after drilling was completed. A double installation was used in Boring J where a well tip was installed at the bottom of the hole and at the contact with the silt at 20 feet depth. A slope inclinometer casing was installed in boring F in order to permit measurement of any future movements in the slope. A geotechnical engineer from our staff was present during the explora- tions. Our representative assisted in locating the borings, obtained repre- sentative soil samples, examined and classified the soils encountered, observed ground water conditions and maintained a detailed log of each exploration. The soils were classified in accordance with the Unified Soil Classification System which is described on Figure A -1. The logs of the explorations are presented on Figures A -2 through A -17. Relatively undisturbed soil samples were obtained from the borings using a heavy -duty sampler with 2 -1/2 -inch brass liner rings. The sampler was driven using a 250 -pound hammer falling a distance of 30 inches. The driving resistance for one foot of penetration is noted on the logs adjacent to the sample notations. All samples were sealed in containers to limit moisture loss, labeled and taken to our laboratory for further examination and testing. LABORATORY TESTING • Selected samples were tested to determine the field moisture and density and strength characteristics. The moisture- density data are presented on the logs of the explorations next to the appropriate sample notations on Figures A -2 through A -18. A- 1 GeoEngineers Incorporated -BORING LOG AND SAMPLE DAT EY DRIVEN SAMPLES BLOWS REQUIRED TO DRIVE SAMPLER ONE FOOT OR INDICATED PENETRATION USING POUND HAMMER MOISTURE FALLING INCHES CONTENT 28 "P" INDICATES SAMPLER PUSHED WITH WEIGHT OF HAMMER 11.2% 111 • INDICATES LOCATION OF UNDISTURBED SAMPLE DRY DENSITY ® INDICATES LOCATION OF DISTURBED SAMPLE IN PCF ❑ INDICATES LOCATION OF SAMPLING ATTEMPT WITH NO RECOVERY FIGURE A -1 OTHER TYPES OF SAMPLES INDICATES LOCATION OF THIN WALL, PITCHER, OR OTHER TYPES OF SAMPLES (SEE TEXT) GRAPHIC LOG LETTER SYMBOL SOIL TYPE DISTINCT CONTACT BETWEEN SOIL STRATA GRADUAL CHANGE BETWEEN SOIL STRATA BOTTOM OF BORING UNIFIED SOIL .CLASSIFICATION SYSTEM MAJOR DIVISIONS COARSE GRAINED SOILS MW THAN MML OF MRTERIM. IS Liars TITAN ND. 1100 SIDE SIR GRAVEL AND GRAVELLY SOILS NOR TON SO% OF COARSE TUN IKTAIN FQ a K1. 4 SIDE CLEAN GRAVELS (LITTLE OR ND rINEsT LETTER SYMBOL GW DESCRIPTIONS RELL- GRADED GRA8LS. CRAWL-SAND sonnies. LITTLE on ND FINES GP nookr-Gnnoto GRAILS. CRAWL - Sap NIXRAES. LITTLE DR ND FINES GRAVELS WITH FINES (APPRECIAILE NOMT Or FINES( GM SILTY GRAILS. GRAIL -SRO -SILT N IXTUES GC CLAYEY GRAVELS, GRVEI -SARD -SILT N ATURES SAND AND SANDY SOILS HORS M NI SOIL Of COARSE AMC- Tim MUM 'O. • SLIM CLEAN SANDS mint/ CO NO FINES) SW (ELL GRACED SANDS. GRAELLY SANDS. LITTLE CO ND FINES SP POORLY-WOW SANDS. GAWLLY SANDS. LITRE 011 ND FINES SANDS WITH FINES (APPREC:AILE mow OF FINES( SM SILTY SANDS. SAM-SILT NIXTIlES SC CLAYEY SANDS. SND{tiAY NIXTUES FINE GRAINED SOILS moll Mom SOIL Of MATERIAL IS SMALLER TOM ND. 100 SIM SIR SILTS AND CLAYS LIQUID LIMIT LESS THAN 50 SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50 ML INORGANIC SILTS. AND WRY FINE SANDS. ROCK nap, SILTY Om CLAYEY FINE SNOS OR CLAYEY SILTS NITH SLIGHT PLASTICITY CL IN:MANIC CLAYS OF LON To NEOIw PLASTICITY. GRAWLLY CLAYS. SNOT CLAYS. SILTY CLAYS. LENT CLAYS OL ORGANIC SILTS AND oR ANIC SILTY CLAYS' Of LOW PLASTICITY MH INWARNIC SILTS. NICACEMS OR DIATO- NACEO S FINE SND aA SILTY SOILS CH INdIG/NIC CLAYS OF NIGH PLASTICITY FAT CLAYS OH Omfr1 TIC CLAYS OF NEOIUN TO NIGH PLASTICITY. ORGANIC SILTS HIGHLY ORGANIC SOILS PT PEAT, MJNJS. SHM SOILS RIM HIGH DRGWIC CONTENTS 'QIF. DUAL SYMBOLS INDICATE 41.1( SOIL CLASSIFICATICN GeoEngineers Inc. 'UNIFIED SOIL CLASSIFICATION SYSTEM AND KEY TO SAMPLE DATA 0 BORING C ELEVATION: 237.1 FEET FIGURE A -2 • DATUM: CITY OF TUKWILA GRAPHIC TEST DATA LOG DESCRIPTION Sir1 BROWN SILTY SAND WITH GRAVEL (STIFF, MOIST) 5 3.8% 99.1 II 5 31.9% 91.5 j X10-+ z rr x. a 31.2% 91.7 29 15 20 30- 3 5 40 -- 28.3% 94.2311 32 24.5% 100.91 53 24.6% 100.5 II 54 6.9% 98.31 53 6" 9.6% 122.8 11 ML ML SP CRAY SANDY SILT WITH RUST STAINS (STIFF, MOIST: GRAY SILT WITH WET FINE SANDY SILT INTERBEDDED (STIFF, MOIST) SLICKENSIDES SLICKENS IDES FINE SANDY SILT LENSES SLICKENSIDES GRAY FINE TO MEDIUM SAND (MEDIUM DENSE TO TO DENSE, MOI S.T) HIT GRAVEL AT 38 FEET FOR 2 FEET, THEN SANDY, THEN BACK INTO GRAVEL GeoEngineers Inc. *SEE KEY FOR EXPLANATION OF SYMBOLS LOG OF EXPLORATION 0 BORING L ELEVATION: 207.5 FEET *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -10 5-' E• 10- z 20' 25-" 30' 35 40— 18 9.8% 122.511 6 35.4$ 84.91 6 3.4% 89.11 8 26.1% 98.011 22 30.7% 92.211 34 29.9% 93.41 51 21.4% 97.011 43 27.6% 96.411 SM ML r BROWN GRAVELLY SILTY SAND (MEDIUM DENSE, MOIST) GRAY SILT WITH REDDISH BROWN STAINS AND FINE SAND INTERBEDDED (SOFT, MOIST) GRADES TO MEDIUM STIFF FRACTURES GRADES TO STIFF 1/8 INCH SAND LENS AT 28i FEET GRADES TO VERY STIFF, DAMP SLICKENSIDE AT 37i FEET *SEE KEY FOR EXPLANATION OF SYMBOLS GeoEngineers Inc. LOG. OF EXPLORATION 40 *GRAPHIC *TEST DATA LOG BORING L (CONTINUED) _DESCRIPTION FIGURE A -1l 45- w t 50 - z rr a w a 55-1 60 65- 73 22.3% 104.4U 86 25.8% 98.411 32 23.5% 104.411 52 6" 13.5% 125.98 ML SM ML SP GM GRAY INTERBEDDED SILT AND FINE SAND (VERY STIFF MOIST) FRACTURES AND SLICKENSIDES GRAY FINE SAND (LOOSE TO MEDIUM DENSE, WET) GRAY SANDY GRAVEL WITH A TRACE TO SOME SILT HEAVE AT 61i FEET BORING COMPLETED AT 63 FEET ON 10/14/83 GROUND WATER LEVEL ESTIMATED AT 49 FEET DURING DRILLING PIEZOMETER INSTALLED AT A DEPTH OF 63 FEET ON 10/14/83 *SEE KEY. FOR EXPLANIATION OF SY148o1.`; GeoEngineers Inc. LOG OF EXPLORATION DEPTH IN FEET 0 BORING H ELEVATION: 229.5 FEET *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -12 5- 10- 15� 2 0- 25- 30- 35- 40-* 6 21 30.5% 90.811 24 30.2% 92.41 22 28.6% 95.211 30.9% 92.2. 24 25.6% 100.411 29 26.2% 99.711 21 28.8% 95.411 SP SP ML BROWN SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE, MOIST) (FILL) TAN TO BROWN FINE SAND WITH RUST STAINS (LOOSE, MOIST) GRAY SILT. WITH SAND LENSES (STIFF, MOIST) WITH A TRACE OF CLAY GeoEngineers Inc. 1 *SEE KEY FOR EXPLANATION OF SYMBOLS LOG OF EXPLORATION DEPTH IN FEET 40 *GRAPHIC *TEST DATA LOG BORING H (CONTINUED) DESCRIPTION FIGURE A -13 45- 50-' 55- 60� 65' 25. 33.1% .90.111 34 29.9% 93.511 46 28.0% 95.911 66 28.2% 96.111 22.6% 102.83 WITH SAND INTERBEDDED, SLICKENSIDES, AND VERTICAL SAND /SILT CONTACT IN SAMPLE GRAY SILT INTERBEDDED WITH SAND VERTICALLY GRAVEL OBSERVED BY DRILLER GRAY SILT INTERBEDDED WITH SAND LENSE AT 70 DEGREE DIP GRAVEL IN BARREL ABOVE SAMPLE BORING COMPLETED AT 62i FEET ON 10/13/82 GROUND WATER OBSERVED AT 55 FEET DURING DRILLING PIEZOMETER INSTALLED AT 62i FEET *SEE KEY FOR EXPLANATION OF SYNROLS GeoEngineers Inc. LOG OF EXPLORATION FIGURE A -14 0 5 BORING J ELEVATION: *GRAPHIC *TEST DATA LOG 195.4 FEET DESCRIPTION 20 - 25- 30-1 3 5 - 40" 50 6' 23.5% 87.01 7 30.2% 90.41 5 28.2% 95.811 32.2% 17 • 18 1.6% 91.011 18 1.8% 88.011 24 2.4% 90.011 22 32.3% 90.011 SM ML BROWN GRAVELLY SILTY SAND WITH WOOD FRAGMENTS (MEDIUM DENSE, MOIST) GRAY SILT INTERBEDDED WITH SAND LENSES (SOFT, MOIST) GRADES TO STIFF WITH SLICKENSIDES AND FRACTURING FRACTURES SLICKENSIDES OCCASIONAL BROWN STAINS SLICKENSIDES *SEE KEY FOR EXPLANATION OF SYMBOI.s GeoEngineers Inc. LOG OF EXPLORATION 40 *GRAPHIC *TEST DATA LOG BORING J (CONTINUED) DESCRIPTION FIGURE A -1 45 - H w 50- z a w 60- 65 70 -� 80— 25 30.9% 92.611 23 32.0% 90.11 29 33.7% 89.011 2 28.7% 93.71 96 3.6% 100.911 47 5.9% 89.811 106 8.3% 106.111 59 6" 8.7% 110.211 ML ML GP WITH SLICKENSIDES AND BROWN STAINS LARGE SLICKENSIDE GRADES TO VERY STIFF FEW SLICKENSIDES WET SAND LENSES AND RUST STAINS GRAY SILT WITH SOME GRAVEL, SLICKENSIDES, RUST STAINS, AND SAND LENSES (VERY STIFF, DAMP) HIT GRAVEL BETWEEN 77 TO 80 FEET *SEE KEY FOR EXPLANATION OF SY!4ROLS GeoEngineers Inc. 1 LOG OF EXPLORATION RAH:GMf'DA 80 85 w z *GRAPHIC *TEST DATA LOG LILLE SP BORING J ,(CONT INUE.D) DESCRIPTION FIGURE A -16 GRAY FINE TO MEDIUM SAND (MEDIUM DENSE, WET) HEAVE AT 82i FEET BORING COMPLETED AT 84 FEET ON 10/15/83 GROUND WATER LEVEL ESTIMATED AT 49i DURING DRILLING PIEZOMETER INSTALLED AT A DEPTH OF 82i FEET AND 20 FEET *SEE KEY FOR EXPLANATION OF SYMROI,S GeoEngineers Inc. LOG OF EXPLORATION BORING K ELEVATION: 175.0 FEET *GRAPHIC *TEST DATA LOG . FIGURE A -17 DESCRIPTION w 10 z H 15� 20 - 25 30.- 35- 40* 13 21.7% 99.611 9. 26.3% 97.011 8 34.1% 87.71 10 28.3% 97.011 5 35.5% 87.311 20 29.8% 92.41 20 26.4% 93.51 36 6.1% 98.211 SM ML BROWN GRAVELLY SILTY SAND WITH RED AND DARK BROWN STAINS (LOOSE TO MEDIUM DENSE, MOIST) GRAY SILT WITH SAND LENSES AND RUST STAINS (STIFF, MOIST) MOTTLED APPEARANCE GRADES TO SOFT AND WET SLICKENSIDES GRADES TO STIFF AND MOIST TO WET SLICKENSIDES AND BROWN STAINS SLICKENSIDES AND BLOCKY FRACTURES *SEE KEY FOR EXPLANATION OF SYI'413O1.S GeoEngineers Inc. LOC OF EXPLORATION 40 BORING K (CONTINUED) *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -18 45— E• w 50 z a ca 55- 60— 65 70— 75— 80 32 27.7% 95.911 54 27.9% 96.71 31 27.1% 96.411 58 30.1% 93.011 82 25.3% 98.411 76 27.0% 98.011 50 4" 24.5% 101.311 65 20.2% 110.0$ ML ML MANY SLICKENSIDES .VERTICAL COLOR CONTACT IN SILT SLICKENSIDES DISTORTIONS IN SAND LENSE SLICKENSIDES GRADES TO VERY STIFF MANY SLICKENSIDES SLICKENSIDE TRACE OF SOME VERY FINE SANDY WET VERY FINE SANDY SILT LENSES GRAY FINE SANDY SILT (STIFF, WET) -.7P--BROWN SILTY SANDY GRAVEL (DENSE, WET) *SEE KEY FOR EXPLANATION OF SYNROLS GeoEngineers Inc. 1 LOG OF EXPLORATION RAN'rMD:nn 80 BORING K (CONTINUED) *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -19 85- 70 6" 23.0% 104.0.11 50 4" 25.9% 98.811 GP ML GRAY FINE SANDY SILT (STIFF, WET) BORING COMPLETED AT 88 FEET 9 INCHES ON 10/17/83 GROUND WATER LEVELS MEASURED AT 14 FEET AND 79.5 FEET DURING DRILLING PIEZOMETER INSTALLED IN GRAVEL LAYER AT 88 FEET • *SEE KEY FOR EXPLANATION OF SYMROLS GeoEngineers Inc. LOG OF EXPLORATION APPENDIX B INSTRUMENTATION AND MONITORING PIEZOMETBIC LEVELS A series of water level. measurements was made in the piezometers installed by GeoEngineers, Inc.; in Piezometers 1A, 1B, and .1 installed by Shannon & Wilson in 1966; and in the Group 1 vertical wells installed by the Washington State Department. of Transportation (WSDOT) during construction of the I -5 /I -405 interchange in the mid- 1960s. The water levels measured in the piezometers and wells since November 1983 are presented in Tables B -1 through B -3. The elevation datum used is the Valvue Sewer District datum. INCLINOMETER. DATA The inclinometer in Boring P was initialized on November 1, 1983. Subsequent sets of readings were taken on November 18, 1983 and March 12, 1985. The readings indicate no discernible movements at this time. The data are available for review or copying from our files. B - 1 GeoEngineers Incorporated TABLE 8 -1 PIEZONETRIC LEVELS - GEOENGINEERS, INC. BORINGS Ground Elevation of Water Table (Feet) Surface Elev. Boring (feet) 11/18/83 11/30/84 3/4/85 3/12/85 C 237.1 196.6 196 197 D 178.8, 172.7(1). 172(1)(2) 123 123 G 179.2 163.3(1) 103 102 H 229.5 189.1 184.5 183.5 J(top) 195.4 184.1 184.5 185.5 185.5 J(bottom) 195.4 167.8(1) 114.5 166.5(1) 114.5 K 175.0 129.5 - (3) L 207.5 177.6 177.5 178 NOTES: (1) High water levels possibly due to surface water infiltration. (2) Reading obtained on 12/12/84. (3) Piezometer K plugged at 7 foot depth. B - 2 GeoEngineers Incorporated TABLE 8 -2 PIEZCNETRIC LEVELS - SHANNON & WILSON PIEZONETEBS Casing Elevation of Water Table Elev. (Feet) Piezometer (feet) 3/4/85 3/12/85 IA 148.5 93.5 93.5 1B 151.5 111.5 111.5 1(1) 165.0 146.5(1) 139 (1) NOTE: (1) Piezometer 1 consists of a slope indicator casing and is obstructed at Elevation 130. • TABLE B -3 PIEZOMETRIC LEVELS - GROUP 1 WSDOT WELLS Casing Elevation of Water Table (feet) Elev. Well No. (feet) 11/30/84 3/4/85 3/12/85 1 161.4 143.5 - 144 144 2 162.6 148.5 147 147 3 162.8 152.0 152.5 152.5 4 .166.2 101 101 5 166.5 103.5 104.5 104.5 6. 166.4 (1) - - 7 163.2 140 140 8 162.1 124 124 9 162.6 109.5 109.5 10 157.5 107.5 107.5 107.5 11 156.8 108 108 108 12 157.3 108.5 108.5 107.5 13 155.0 104 104 14 153.8 111 112 112 15 152.8 113 113 16 147.4 116.5 115.5 17 146.6 116.5 116.5 18 145.4 117.5 116.5 19 . 136.5 94.5 94.5 20 135.1 118 118 21a - (2) 21b 133.1 117 117 116 22 131.0 dry at 86' dry at 86' dry at 86' 23 131.3 96.5 97.5 24 130.3 97 96.5 NOTES: (1) Well No. 6 plugged at 9 foot depth. (2) Well No. 21a plugged at 10 foot depth. • TABLE B-4 GROUP 1 WSDOT VERTICAL WELL /HORIZONTAL DRAIN SYSTEM Well Horizontal Drain Parameters Ground GEI WSDOT Surface Pump Elevation Outlet Well Well No. Elevation Elevation at Well Elevation Grade Length No. Series No. Feet Feet Feet Feet. X Feet 1 I 1 159.6 60.1 80.9 80.5 2 213.0 2 2 160.1 61.0 82.6 80.5 1 222.6 3 3 160.5 56.0 . 81.6 80.5 2 223.1 4 II 1 164.6 54.5 82.1 81.7 2 233.6 5 2 164.3 51.8 82.8 82.8 2 223.4 6 3 164.1 51.6 86.9 82.6 2 223.6 7 III 1 162.3 53.4 83.4 83.3 2 223.7 8 2 161.5 51.3 88.0 83.9 2 212.8 9 3 161.0 52.7 86.5 84.4. 1 213.7 10 Iv 1 156.7 50.6 .84.5 84.9 0 204.9 11 2 155.4 53.0 87.3 85.0 1 203.3 12 3. 156.5 51.4 90.1 86.2 2 214.8 13 V 1 153.3 50.2 87.8 87.4 1 183.8 14 2 152.4 54.2 89.7 88.0 1 184.3 15 3 151.2 N/S 90.1 88.4 1 184.7 16 VI 1 145.7 42.5. 90.6 89.8 2 152.8 e17 2 144.7 N/S _ 92.0 90.6 1 153.2 18 3 143.8 62.8 92.4 91.0 1 . 152.9 19 VII 1 133.5 N/S 93.7 93.0 . 1 134.8 20 2 132.9 N/S 95.8 94.5 1 135.1 21 3 132.2 N/S 94.6 94.6. 0 126.6 22 VIII 1 128.2 N/S 97.1 97.1 0 95.0 23 2 128.9 N/S 97.5 97.5 0 84.8 24 3 128.6 N/S 97.9 97.9 0 85.5 N/S Not shown on WSDOT documents. APPENDIX C SLOPE STABILITY ANALYSIS INTRODUCTION A description of the slope stability analyses for the deep- seated sliding failure mode and the results are presented in this appendix. Methodology: Deep- seated block -type eliding was analyzed with the aid of the computer program STABL, which allows analyses of shear surfaces of general shapes, including sliding blocks. The program is based on Carter.'s Method. Critical failure surfaces are generated using pseudo random techni- ques. The input parameters include slope topography, piezometric levels in the lower sand aquifer, soil strengths, earthquake acceleration coefficients and building loads on the slope.. The initial phase of our analyses included back- calculating soil strengths from conditions existing during eliding in 1961. The back - calculated soil strengths were obtained by changing the input values to achieve a computed factor of safety of about 1.0. These strengths, along with water level and topographic information were used to compute a new factor of safety for conditions existing in March 1985.. The effects of water level rise, earthquake loading, and building loads on the factor of safety were then evaluated. Assumptions: Several assumptions were necessary in.evaluating deep - seated block sliding stability. Topography representative of conditions existing in 1961 (soon after the major slide of 1960) and those existing at present (1985). were evaluated. Topographic conditions assumed in 1961 were based on Plate 3 of the Dames & Moore report dated June 27, 1961. Topographic conditions existing at present (1985) are based on topographic information provided by Stepan & Associates, Inc. for the section of the slope located between the uphill. and downhill property lines. Topography below the downhill property line and above the uphill property line was .estimated from Figure 1 in the Shannon b Wilson report dated June 21, 1968. The sections judged most critical of those used in our analyses are shown on Figures C -1 and C -2 for the 1961 and 1985 topographies, respectively. C - 1 GeoEngineers Incorporated • • . The location of the section depicted on Figure C -1 and C -2 is shown on Figure 1. The location of the section used in the 1961 Dames & Moore report differs from that used in our analyses and is located to the southeast of the section we have used. The section shown on Figure C -2 is drawn through the center of a large swale, while the borings drilled both for our studies and by Dames & Moore are located on the flanks of this swale. The differences in topographic conditions shown in 1961 and 1985 indicates that a significant amount of material is absent from the lower portion of the slide area, particularly below the downhill property line. The difference could be attributable to material removal as well as to the different sections used by Dames b Moore and GeoEngineers. Soil conditions depicted in all of the borings used to develop our cross sections vary significantly. This is especially true of Borings DM-1 and D, DM -3 and G, and DM -4 and C. Variations across the swale are also apparent when comparing the logs for Borings DM -1 and DM -3 with D and G, respectively. The presence and variable elevations of sand lenses throughout the thick fine - grained layer (Unit B) probably account for the major part of this variability. They also have a significant influence on the location of the failure surface. The location of failure zones identified from slope indicator measurements in the Dames & Moore borings and zones of slickensided material encountered in Borings C, D, G, L and F were used to estimate the probable location of the slide plane in our analyses. See Figure 1. For both topographic conditions (1961 and 1985), the soil conditions were simplified to a three -layer system. The uppermost layer includes the surficial silty sand and thick fine - grained soil units (Units A and B shown in Figure 1). The second layer (underlying the thick fine - grained soil unit) was assumed as a thin (5- foot - thick) zone of weak material through which the slide plane passes. Material underlying this weak layer was assigned a higher strength and represents dense glacially compacted soils through which the slide plane probably does not pass. The extent of the weak zone was estimated from our borings and the Dames & Moore borings. C-2 GeoEngineers Incorporated • • Water levels for the 1961 analysis had to be estimated.as artesian conditions existed at the.time the borings were drilled by Dames 6 Moore in 1961. Based on the observations by Dames & Moore personnel of the rate of flow from the borings, the piezometric surface was assumed at 5 feet above the existing ground surface. Water level information from our borings and Shannon & Wilson Piezometers 1, lA and 1B were used to establish the piezometric surface existing in 1985. The sliding block failure surface was modeled using five constraint areas positioned. along the lower boundary of the assumed-weak zone. The downhill exit point for the slide was based on. the exit point indicated in the. 1961 Dames & Moore report. This exit point may have been observed at that time because this portion of the site was cleared as a result of borrow operations. The failure surfaces are shown in Figures C -1 and C -2 for 1961 and 1985, respectively. Selection of Parameters: The analyses using 1961 conditions were performed by varying soil strengths of the upper two soil layers until a factor of safety of approximately 1.0•was obtained. The friction angles for this condition were computed at 25. degrees for the upper material and 15 degrees for the weak zone material. These friction angles are considered to-be residual values and the cohesion intercepts were accordingly assumed to be zero. The analyses indicate a zone of'critical failure surfaces having nearly equal factors of safety near the uphill property line. See Figure C -1. Results: Tie failure surface and piezometric conditions evaluated for existing conditions are shown in Figure C -2. The analyses indicate a factor of safety of. 1.5 to 1.6 for the section assumed in the analysis. .Our analyses of the stability of sections located outside•of the awale yield factors of safety approximately the same for existing piezometric conditions. Additional Analyses: We then evaluated the effects of an increase in the water level. Factors of safety of 1.3 and 1.0 were obtained when the piezometric levels were raised 10- and 20 -feet, respectively, above existing levels. GeoEngineers Incorporated • • We also evaluated the effect of the building loads on deep- seated -stability by assuming an average areal building load of 200 pounds per square foot extending over the building footprints at two locations on the slope. The factor of safety obtained for this loading condition was nearly identical with that obtained without building loads. Dynamic Analysis: Dynamic stability was evaluated by subjecting the . slope to a horizontal acceleration coefficient of 0.15 with the piezometric surface at current levels. We assigned a cohesion value of 500 psf and a friction angle of 15 degrees to the weak zone to represent undrained soil strength. This is considered to be conservative and to be more appropriate for earthquake loading. A factor of safety of 1.13 was obtained for these conditions. While the factor of safety indicated for dynamic loading conditions is relatively low, this value is considered, in general practice, to provide a level of risk comparable to a factor of safety of 1.5 for static conditions. Strains and, therefore, slope movement developed during earthquake loading will probably be limited. This is normally observed in cohesive soils during earthquake loading and is indicated by the reported localized zones of cracking in the uphill portion of the slide area during the 1965 Seattle earthquake. c GeoEngineers Incorporated FIGURE C -1 340— 320-- 200^ 260 TOO- z 0 I60 120— 00 411—. 0.100) (0,02) (0,64) 016,116) (245,162) PROPERT0 LINE 1961 Topography ESTIMATED P1EZONETRIC LEVEL (166,171) 20NE OF GENERATED CRITICAL FAILURE SURFACES PROPERTY LINE I ISLADE NAY I(000.275)-100 ()06,251) (120 252) 1 125 PCF SOIL p C c 0 .--240 0 = 26:10,220) —520 (121,11) (166,111) SL1D1NG *LOLL IAINUM1 SUMNALI (526,166) (110,209) 200 —160 4 (100,204) SOIL O 0 = 120 PCF C = 0 • = IS' SOIL U 0 = 110 PCf C = 0 • = 15' —120 00 —40 1 T 1 1 I 1 r r I I l 1 I 60 10 110 160 200 260 200 .120 560 400 440 400 520 DISTANCE IN FEET Nulls: 1) SICIION LINE IS SECTION A -A' SIWNN IN E11.URL 1. 2) 10POCRAPNY BASED ON PERIL $ IN DANES t NUORf REPORT DAIIO 6/21/61. AND CORRESPONDS 10 CONDIIIONS 11151- ' 1NO. *11(0 SLID! Of 1960-61. 1) rA1111 1(0(15 1SI(NAIED fRON 000IN2S DRILLED 111 DAN S t 110001 IN 1961. 1 r 1 1 1 1 1 r 560 600 640 600 120 760 000 040 600 GeoEngineers Inc. CROSS SECTION FOR STANI L I 1 Y APPENDIX B UTILITIES REPORT FIGURE C -Z 160,— 320— 280— 740 — 200 1985 Topography PROPERTY LINE ZONE OF GENERATED I SLAVE WAY I CRITICAL FAILURE 1 SURFACES .207)' (706,751) — 1600 (100,275) ESTIMATED PIEZOMETRIC SURFACE PROPERTY LINE (457,177 (542.200 i 160 120— 00 (102,141) (0,100) (242,115) (0.69) 40 - 0 (0.64) (120,01) (164,111) 51101141. 000(4 IAILUYE SYRFACL 1 I - 1 1 1 1 1 40 80 120 160 • 200 240 200 N01(S: I) SEC110N LINE IS SECTION A -A' SHOWN IN FIGURE 1. 7) IOPOGRAPHI BELOW 00NNN166 PROPERTY 1114E AND ABOVE uPnill PROPERTY LINE BASED ON FIGURE '1 IN SHANNON 1 WILSON REPORI DATED 6/71/60. I) TOPOGRAPHY BETWEEN PROPERIY LINES BASED ON PRE - LIMINARY IOPOGRAPMIC MAP PROVIDED BY S1(PAN 6 ASSOCIAIES, INC., DATED MARCI, 1905. 4) WAI(R 1(V(LS BASED ON MEASUREMENTS MADI IN PICZUMIICRS 1451ALII0 00 6(DEN6INIERS AND SMANNUN 6 WILSON, AND IN 6RUUP 1 VIRIICAI DRAINAGE WCILS INSTALLED B1 W5UU1. (026,171) (026,166) SOIL (J ! = 120 PCF C =0 • = Ir SOIL OI 6 = 130 PCF C = 0 • = 15 (000,204 —120 — 200 240 (000,22/) 0180,204) 200 z — 160 0 --170 —BO —40 stu 1 1 1 1 I T 160 400 440 410 520 560 DISIANCE IN FEE] 1 r 1 640 600 600 1 1 1 1 720 160 000 040 080 0 GeoEngineers Inc. CkUSL 5111111( 1 O S1AIi1111T ANAL 1.15 • • / —ti' / EXISTING STORM 4\11[ I EXISTING STORM SYSTEM & EASEMENT j••o a rs. _ _ - r---�` �1- --------- •., =_� ` \ ea• CONTROL MH J ` / / c)c"° °\� VALLEY � ALLEY VIEW ESTATES /.\\ SITE SITE UTILITY PLAN S 1—S%'\ FIGURE 18 EXISTING SEWER & EASEMEN'r LEGEND g 'PROPOSED STORM LINE vvvkmOROPOSED WATER LINE ■U• ■PROPOSED SANITARY SEWER 11?. VALLEY VIEW ESTATES UTILITY REPORT Prepared By: STEPAN & ASSOCIATES, INC. 930 SOUTH 336TH STREET FEDERAL WAY, WASHINGTON 98003 5 -1 -85 STORMWATER RUNOFF /ABSORPTION EXISTING CONDITIONS The site slopes generally from west to east with a drainage swale bisect- ing the southern portion of the site. Slopes vary from 3% to 50 %. Site vege- tation consists of alder, a few maple and dense blackberry vines. As stated in the surface water portion of the geotechnical report pre- pared by Geo Engineers, permeability is relatively low in Units A and B (ref. Figure 4 in the geotechnical report) and significantly higher in Unit C. The Washington State Department of Transportation has installed a series of large diameter wells and horizontal drains just east of the site to modify and control the water table (Ref. Figure 1 in the geotechnical report). This sys- tem was installed during the construction of Interstate 5. This will be referred to as the WSDOT system in the remainder of this report. Impacts: Existing surface runoff and absorption characteristics would be altered by aspects of the proposed development: the installation of drainage systems, removal of vegetation during site preparation, fill and grading, and introduction of impervious surfaces on the site in the form of roads, parking areas, and structures. Off -site features such as the City of Seattle water line should not be effected by the proposed development. Absorption would be reduced, and the volume of runoff would be increased as described below. Mitigating Measures: The proposed stormwater facilities as shown on the attached Site Utility Plan and sub - surface facilities as described in the geotechnical report prepared by GeoEngineers would mitigate the impacts of site development on runoff and absorption characteristics. The engineering drawings for the storm water system will be prepared in accordance with City of Tukwila requirements and are subject to City review and approval. SURFACE WATER MOVEMENT AND QUANTITY Existing Conditions: The site drainage basin is bounded by Slade Way and the extension of 158th Street on the north. The basin area is 7.2 acres and is divided into 2 sub basins the south being 4.4 acres and the north 2.8 acres. Drainage from the site flows directly to the Green River through a series of pipes and open channels which are described below. Surface runoff from the southern portion of the site (4.4 acres)'sheet flows to a rip -rap lined ditch which bisects the south side of the site. This ditch flows to a receiving structure on the south side of Klickitat Drive. A 24 -inch pipe runs from the receiving structure to.a manhole where the pipe size increases to 30" under Klickitat Drive. This 30 -inch line then runs para- llel to Klickitat and connects to a 48" line which runs parallel to the north- bound lane of Interstate 5. The 48 -inch line then crosses under Interstate 5 and discharges in a lined open channel which is on the west and north side of Southcenter Parkway. The channel flows through a short section of 78 -inch pipe and a section of 108 -inch pipe and then discharges in the Green River. • . • Surface runoff from the north portion of the site (2.8 acres) sheet flows to a lined ditch along the east side of the site. The ditch flows to a receiv- ing structure near the northeast corner of the site. An 18 -inch pipe runs from the structure to a manhole where the pipe size increases to 24 ". This line runs under Interstate 5 and ties into the same 48 -inch line which was described in the preceding paragraph. The flows follow . the same route to the Green River as described for the southern portion of the site. The WSDOT system of vertical wells are connected to horizontal drains which also flow to the systems described above. Off -site flow from approximately 12 acres of mostly single - family resi- dences west of Slade Way and south of South 160th Street enters the site south of the intersection to South 160th Street and 53rd Avenue South. Part of this system parallel to 53rd Road South runs above ground, and is leaking (observa- tion 10/17/83), causing some ponding in the immediate area. The system also consists of 12 -inch and 18 -inch underground pipe and runs generally in a north - south direction. This pipe connects to the same 24 -inch line described in the paragraph above. From here the runoff travels the same path to the Green River as that previously described. Impacts: Construction of the proposed development would not alter existing drainage basin boundaries. Site development would eliminate existing natural surface flow and infiltration characteristics and introduce an addi- tional buried conduit system. The new drainage collection system would con -. tain and direct surface water at higher velocities and in different directions across the site, as shown on the Site Utility Plan; however, stormwater would continue to exit the property at the same points along the southern an eastern boundary. Changes in potential peak flow of storm runoff due to building construc- tion and paving will be controlled by the drainage retention and runoff con- trol system. Surface water would be collected in a subsurface conduit system as shown on the site utility plan, which would direct stormwater drainage at higher velocities and in slightly different directions across the site. The new storm sytem would also collect existing on -site horizontal drains (ref. Figure 3 - GeoEngineers Report and footing and retaining wall drains. The proposed drainage system includes storm drainage retention pipes and control structures which would control and store storm water to limit the runoff rate to a predevelopment rate. Therefore, surface water would exit the site at approximately the same rate as it does under existing conditions. The installation of a storm drain system would provide positive benefits because it would collect and channel surface water, some of which is currently flowing in ill - defined channels, and direct it to a controlled system outflow. The storm drain system and the system of foundation wall drains will also increase the factor of safety against sliding in the upper layers of soil (Ref. page 15 geotechnical report) and provide less impact on the WSDOT System (Ref. page 23). The 7.2 acre drainage basin is divided into 2 sub basins the south being 4.4 acres and the north 2.8 acres. Based on a storm of 10 year recurrence interval, the south basin would require approximately 1,500 cu. ft. of storage capacity, and the north basin would require approximately 1,000 cu. ft. of storage. The size of the controlled outlet from the site would be runoff at a rate that would not exceed existing conditions. -2- • • Since runoff from the site flows directly to the Green River as detailed in the preceding paragraphs, an alternate to this would be to provide no deten- tion for the site. This is a normal practice on sites which flow directly to a large body of water or river. - There would be several benefits from this. The principal benefit would be elimination of a possible source of water leakage from the detention struc- ture. It would also eliminate some of the excavation and disturbance of the hillside on -site. As shown on the attached storm calculation sheet the introduction of impervious surfaces would increase the peak surface runoff from a total of 1.36 cubic feet per second (CFS) to approximately 3.34 CFS during 10 -year storm conditions. This is an increase of 1.98 CFS at the peak. Surface run- off would increase a total of 1.67 CFS to 4.13 CFS during a 25 -year storm. This is an increase of 2.46 CFS at the peak runoff. This is a relatively small increase given the size and capacity of the downstream storm system which is capable of handling 20 CFS or greater. Mitigating Measures: A stormwater system designed in accordance with City of Tukwila requirements and requirements and recommendations detailed in the geotechnical report prepared by Geo Engineers is proposed to be installed. The City of Tukwila must approve stormwater drainage plans prior to issuance of the building permit. The site development sequence and facilities as recommended in the geotechnical report prepared by GeoEngineers would be included on the detailed site grading plan. A temporary storm management system and the erosion control measures as described in the geotechnical report will be employed during construction. Where possible, natural vegetation for silt control will be maintained. Temporary siltation ponds shall be constructed by placing straw bales across swales. All temporary and erosion control measures will be maintained in a satisfactory condition until such time as cleaning and /or construction is completed and permanent drainage facilities are operational. The temporary siltation ponds should not effect the groundwater table. The proponent would have maintenance responsibility for the drainage control facilities during construction, and it is proposed that the owner assumes maintenance responsibility for these on -site facilities after comple- tion of the development. Cleaning, flushing and regular maintenance of the WSDOT drain systems described in the geotechnical report is essential. A portion of the existing storm system would be abandoned (See Appendix - Letter from Department of Transportation) and replaced by a new storm line to handle off -site runoff as shown on the site utility plan. The existing storm line that is above ground and leaking would be repaired. Surface Water Quality Existing Conditions: There is no known water quality data for surface runoff from the site. -3- • • Impacts: The introduction of impervious surfaces over a portion of the proposed development would reduce the area of exposed soils. Therefore, reduced quantities of sediment, nutrients, and organic material contained in the soil would be . expected to leave the site in surface runoff. However, in place of these would be contaminants more typical of residential developments: petroleum residues, traces of heavy metals, and sediments washed from roads and driveways. The increased quantity of impervious surfaces would increase the volume of stormwater runoff from the site. Catch basins and oil /water separators proposed within the on -site drainage collection system would func- tion to separate sediments and petroleum residues from stormwater to a certain extent. On -site drainage detention and the outlet control structure would further allow for separation of these pollutants from storm water before release from the site. Use of pesticides, herbicides, and fertilizers (if any) on yards and on landscaping in common areas may occasionally contribute slight quantities of contaminants to stormwater that would not be removed by the proposed pollution separation devices. Also, the partial coverage of soils with asphalt paving and structures may result in slight elevation of temperature of runoff from these surfaces. Perhaps the greatest significant potential for adverse impact on surface water quality would be during temporary construction periods. Clearing and grading would expose soils on the site to potential erosion by rainfall. Mitigating Measures: The proponent would have maintenance responsibility for the on -site drainage control facilities. Cleaning, flushing and regular maintenace of the existng WSDOT systems as described in the geotechnical report is essential. Catch basins and oil /water separators should be cleaned frequently and properly maintained to assure maximum attainable pollution separation. SANITARY SEWER SYSTEM Existing Condition: The site would be served by. Val Vue Sewer District. There is an existing 12 -inch cast iron sewage main which runs through the site as shown on the utility site plan. The line connects to Metro at the Hat Highlands connection. Sewage from the site would be treated at the Renton Sewage Treatment Plant and would be transmitted to the plant via the freeway interceptor, Val Vue outfall and Tukwila interceptor. The proposed project is within Metro's Renton treatment plant service area. Metro has prepared a facilities plan for the Renton system with a grant from DOE and EPA, in part because the Renton treatment plant has reached its "design" capacity and continued development is occurring within the service area. A final plan for the Renton service area was adopted by the Metro Council in November, 1981 and contains a recommended program for upgrading the Renton system so that water quality and health will continue to be protectect- ed. The plan was amended on April 5, 1984 to revise the alignment for the effluent transfer system pipeline. These improvements will be on line in early. 1987. Im act: The on -site sewage collection system would be designed by the proponent s engineer and would be installed as shown on the site utility plan. Six- and eight -inch lines would collect sewage throughout the project and con- nect into the existing Val Vue sewer line as shown. A field survey of this area has recently been completed which indicates the existing sanitary sewer would be relocated so that it will not be under the proposed buildings. This is indicated on the site utilty plan. As per the attached letter from Val Vue Sewer District the relocation construction of this line can occur without any disruption of service in the existing line. The development will result,in increased sewage flows. As stated above, the Renton Treatment Plant is currently treating more than design capacity but temporary measures are being taken which will accommodate flows. The plant will be upgraded by early 1987 if present plans are implemented. Mitigating Measures: If water use was reduced by residents implementing water - saving measures in their homes, the volume of sewage that would be discharged from the project area would also be reduced. SOLID WASTE Existing Conditions: The business and residences in the surrounding vicinity are currently served by Sea -Tac Disposal. Dumpsters and compactors can be rented. from them. The solid waste is taken to the King County Transfer Station. Impacts: The proposed development will increase demand for solid waste collection which can adequately be provided by Sea -Tac Disposal. Mitigating Measures: None WATER SYSTEM Existing Conditions: The project is located in Water District No. 75 service area and would be served from the District's supply and distribution system (ref. letters to and from Water District No. 75, attached). The District is supplied from the large Cedar River Pipeline which runs adjacent to the site. The District anticipates that this source will be able to meet long -range demands for water in this area. (Conversation with Duane Huskey on 3/26/85). The District has a 6 -inch main that extends to the intersection of South 160th Street and 53rd Avenue South. There is also an 8 -inch main that extends east on South 166th Street and terminates approximately 200 feet west of the intersection with 54th Avenue South. Static pressure in this area is 125 psi. Im acts: The District's water distribution would be extended from the 6 -inch man in South 160th Street with a new 8" main on Slade Way. This would be as called for in the District's Comprehensive Plan. Connections from this main would supply the proposed development with water. Fire hydrants will be spaced as required to provide adequate fire protection. The water system would be designed by the proponent's engineer. This existing system could. supply adequate fire and potable water flow to the proposed development. (Conversation with Duane Huskey on 3/25/85). The system within the development would be maintained by the owners. The system within the Slade Way right -of -way would be maintained by Water District No. 75. Installation of the water system to serve the proposed development could have short -term impacts on vehicular travel on Slade Way where trenching is required within the right -of -way or across the road. During actual connec- tion of the project system to the District system, water service in the area could be interrupted for brief periods of time. Implementation of the proposal would result in a long-term commitment of the District water supply to serve the proposed development; however, as stated above,. the District does not expect to experience difficulty in meeting long -range demands in the area. The .proposed on -site system would comply with City of Tukwila fire flow and hydrant- spacing requirements, as well as with the requirements of the Washington State Department of Social and Health Services. The on -site system would comply with Water District No. 75 installation requirements including those to prevent a cross - connection between water and sewer. According to Washington Survey and Rating Bureau criteria, approximately 2100 gpm (see appendix for calculations) is the required fire flow for multi - family develop- ments of this type. The proposed system would meet the minimum criteria. Projected domestic water usage for the site should not exceed 0.04 mgd on a peak day (see appendix for calculations). Mitigating Measures: Installation of water- saving fixtures and devices such as flow restrictors in new dwelling units (at the discretion of the builder) could reduce water consumption, but the feasibility and necessity of this is doubtful. .� -� EXISTING STORM SYSTEM & EASEMENT 1 /. / EXISTING STORM / /-1 INTERCEPTOR TRENCH �-- L_--- - - - - - - 33" RO#W 3 11 MIMI =NM MOM FRE_SpRAI pcAL) CONTROL MH 00 DETENTIi PIPE EXISTING SEWER & EASEMEN?' VALLEY VIEW ESTATES SITE UTILITY PLAN • LEGEND •�' •'PROPOSED FRENCH DRAIN Ammammr PROPOSED INTERCEPTOR TRENCH EMI •PROPOSED STORM LINE vvv∎N PROPOSED WATER LINE APPENDIX VALLEY VIEW ESTATES Preliminary Storm Drainage Analysis Storm Drainage Criteria The storm drainage system for the proposed project as previously described shall be based upon the following criteria. These criteria and method of analysis are quoted from the "Requirements and Guidelines for Storm Drainage Control in King County ", Division of Hydraulics, King County, May 1979 and that document should be referenced for additional information. 1. Runoff Rate Q = CIA where 0 = Rate of flow in cubic feet /second C = Runoff co- efficient based on relative imperviousness of the area i = Rainfall intensity in inches /hour for Seattle area A = Area of runoff in acres 2. Calculation of drainage pipes, ditches and other facilities will be completed, based on requirements with design of the final facilities. Southn Basin Area in basin = 4.4 acres Travel length = 500 feet Velocity (slope average 25%) = 1.3 FPS (bare ground) Travel Time = 10 + 500 = 16.4 minutes 1.3(60) = 1.25 inch /min. i 25 = 1.55 inch/min. 1QSeattle) existing Existing 10 -year peak rate = Q existing = CiA = (.15)(1.25)(4.4) = 0.83 cfs Existing 25 -year peak rate = Q existing = 0.15 (1.55)(4.4) = 1.02 cfs CFuture 2.1 ac (0.90) + 5.0 ac (.15) = 0.37 .1 Future 10 -year peak = (.37)(1.25)(4.4) = 2.04 cfs Future 25 -year peak = (.37)(1.55)(4.0) = 2.52 cfs 00 = 0existing. Area (. future) • • T = -25 + 1763 = 34 minutes 0.5T Vs = 2P20(34 - 40(0.51) 3 2. + 0.83 = 0.51 4.4(0.37) = 931 ft.3/Acre 1 "c" future) VT = 931 (4.4)(.37) = 1516 ft.3 detention volume North Basin Area in basin - 2.8 acres Travel length = 500 feet Velocity = 1.3 fps Travel Time = 10 + 500 = 16.4 minutes 1.3(60) 110 = 1.25 inch/min, i25 = 1.55 "c " existing = .15 Existing 25 -year peak = 0.15 (1.55)(2.8) .= 0.65 cfs Existing 10 -year peak rate= 0existing = CiA = (0.15)(1.25)(2.8) = 0.53 cfs Cfuture = 2.1(0.9) + 5(1.5) = 0.37 7.1 Future 10 -year peak = .37 (1.25)(2.8) = 1.30 cfs Future 25 -year peak = .37 (1.55)(2.8) = 1.61 cfs 00 = °existing = .53 = 0.51 Area ( "c" future) 2.8(.37) T = -25 + 1762 = 34 minutes 0..5T = 2820(34) - 40(0.51)34 = 931 ft.3 /Acre ( "c " existing) . 25 + 34 VT = 431(2.8).37 = 965 ft.3 detention volume Fire Flow Requirements F= 18 (A)0.5 *. C= 1.5 Wood Frame Construction A= 5,248 Square Feet F= 18 (1.5(5248)0'5 1,956 ypn use 2,000 9Pn Less 25% (low hazard occupancy) -500 ,500 Plus Exposures (20% + 20%) =40% = 1+ +600 2,100 gpn Projected Water Usage Multi Family -.90 gal /unit -day Peaking Factor = 18 + p P- poulation in thousands 4 + p P = 18 + 0.216 = 4.14 4'+ 0.216 Flow = 90 gal/unity-day x 108 units x 4.14 = 0.04 million gallons per day 1,000,000 gal /mg * Guide for determination of required fire flow; Insurance Service Office Sanitary Sewer Flow Multi - Family 90 gal /unit -day Infiltration Inflow =.1,100 gal /ac -day; 7.2 acres Peaking factor = 18 + P = 4.14 Flow = 90x108x4.14 + 1,100 x7.2 = 0.05 million gallons per day 1,000,000 7 STEPAN & ASSOCIATES, Inc. Mr. Richard Johnson Design Engineer Dept. of Transportation State of Washington 9611 S.E. 36th Street Mercer Island, WA 98040 Reference: Valley View Estates E.I.S. Dear Richard: April 16, 1985 After discussions with the soils consultant, GeoEngineers, we would like to request on behalf of Puget Western, Inc. the following 1) The horizontal drains be flushed and cleaned. Also do the horizontal drains consist of 10' of stainless steel screen and the remainder tight - line to the vertical wells? The horizontal drainage and /or vertical wells appear to be plugged since the water level in the wells is at a higher level than where the horizontal drains intersect the vertical wells. 2) The vertical wells be flushed and cleaned. Also bolt in place and lock the covered plates on the wells. 3) What is the status and condition of the pumps that are currently in the wells. What is the status of the condition and location of those that have been removed from the wells? 4) A repair and flushing of the original test drains shown on the attached sketch. Also any documents as to where these drains connect to. If you have any questions, please contact Jack Tuttle or Gordon Denby at 881 -7900 or myself at 682 -4771. Very truly yours, STEP N S AS�CIATES, INC. Glenn McKinney, P.E. Vice President GM /gc cc: Joel Niggard, Attorney Tom Russell, Puget Western Jack Tuttle, GeoEngineers • 930 South 336th Street, Suite A • Federal N.ay, Washington 980M11 • !Aroma 9:7.71150. Seattle 68t.4771 • 4- 44.4 - 4 %4. r 1 H,uR E 2 .L • • • • o Project Sit. '. • 0 Approximate Extent of Slide 4- 20-6 1 100 200 300 Scale In Feet Reference: Drawing entitled "PLan of Completed Remedial Meaaurea" by Shannon b Wilson dated March 31, 1966. Legend: Horizontal Drains (existing). •••••-••-••• -•• Original Test Drains Recommended Drain (Grade: 1 -32) mmommmCylinder Pile Wall wwwwdoweExisting or Proposed Right of Way ♦ Additional Vertical Drains (6-9 in. dia.) • Large Diameter (5') Deep Well 4:1 Final Excavated Slope (horizontal:vertical) • Piezometer Installed During 1966 Investigation lUk∎ l l l' 1 . Eft k N( `f k KIN(. r e. STEPAN &ASSOCIATES, Inc. April 17, 1985 Mr. Duane Huskey, P.E. Water District No. 75 P.O. Box 68100 Riverton Heights Station Seattle, WA 98168 Reference: .Valley View Estates Water Service Dear Dwain: As per your letter of April 10, 1985, an 8 -inch main, not a 6 -inch main would be installed in Slade Way. Also attached for your review is a rough draft of the water portion of the Valley View E.I.S. Please call me if you have any questions or comments. Very truly yours, STEPAN & ASSOCIATES, INC. Glenn McKinney, P.E. Vice President • GM /gc Attachment. • 440 South 3 ibth Street. luirr• A • F,.dprel ,i4, W,ishin);tun 481$44 • I,,rnmd 027 7/45(1, S,.,,rtl,. 4041 .r • 2 or 5� INGINI(RING STEPAN & ASSOCIATES, Inc. Mr. Duane Huskey, P.E. Water District No. 75 P.O. Box 68100 Riverton Heights Station Seattle, WA 98168. Reference: Water Service Slade Way for Proposed Valley View Project March 25, 1985 Dear Duane: As per our discussion, a new 6" main from your existing 6 ", line in South 160th Street to your existing 8" main in South 166th Street would provide adequate fire (2100 gpm) and domestic flow. Water District No. 75 would pay for the portion of the new main in 54th Avenue. If you have any questions, please contact me. Very truly yours, Glenn McKinney, P.E. Vice President GM /gc cc: T. Russell J. Haggard • 930 South 336th Street, Suite A • Frdpral Wav, Washington 98003 • lecoma. 927 -7850, Seattle. M2.4771 • DAN N TaL7.- IELL GEORGE _ c. _.: M5ER� .�.,.: JERRY P. HARRIS. Commissioner • litia/er 2,jipici 7/. April 10, 1985 /rt9 t. ounfy r. . SEATTLE. WASHINGTON 98168 Stepan & Associates, Inc. 930 South 336th Street Suite A Federal Way, Washington 98003 Attention: Mr. Glenn McKinney, P.E. Vice President Dear Glenn: KEN HALL KENT HAYDEN DUANE HUSKEY CLIFF BARTLETT There seems to be some misunderstanding of the information, either the way I told it to you or the way you heard it, on the new main for the Valley View project on Slade Way. The calculations that we performed showed that by extending a new 8" line from our existing 6" line on South 160th Street, the 2,100 gpm domestic fire flow could be met. The portion of the main along 54th Avenue South is not scheduled for construction at this time but would be connected to the main installed for this project. Please call me if you have any questions. Sincerely, .Duane Huskey, P.E. DH:tmw cc: Ken Hall, Manager, WD #75 TO wA2 DIST NO. 75 LFLETT.3 cw TuRienTITIMI, 19883 28th Ave. South Seattle. Washington 98188 Bus: 824-0375 SA/ ct ,4s.5 c. L f,4 --E� r't) ✓.4 y N ' . f -mac; 0.3 WE ARE SENDING YOU Attached C Under separate cover via ❑ Shop drawings ❑ Copy of letter C Prints C Change order DATE - [JOE NO. ION ac i4! /itc k, A . Ai c ? •5. eJi.7wTz,AiE Le(..3.—.o. ./ s (6 441, -1 ✓.Ec.: tS-4i, ❑ Plans ❑ Samples (Er ✓.c -.,v. —y "f—s0 the following items: ❑ Specifications COPIES DATE NO. DESCRIPTION THESE ARE TRANSMITTED as checked below: ❑ For approval ❑ Approved as submitted 131-"Fror your use 0 Approved as noted EKAs requested ❑ Returned for corrections 0 Return _ ❑ For review and comment ❑ Tracings ❑ Signature ❑ Legal description ❑ Quotation ❑ Payment ❑ Approved bills ❑ FOR BIOS DUE 19 0 PRINTS RETURNED AFTER LOAN TO US REMARKS ❑ Resubmit copies for approval O Submit copies for distribution corrected prints COPY TO SIGNED: 3- • £ �� t•tI o ~I - -LP! ° • 0229! • 1S Hl b9/ i ;, � • * ffr DAN N C= ,. ^'.:'E._. P- ec, -je•-. GEORC-c _ JERRY P. r.ARRIS, Comm ssw- t. "afFr i.sfri,f January 11, 1985 KEN HALL KENT HAYDEN DUANE HUSKEY CLIFF BARTLETT • It r? nu n ft SEATTLE. WASHINGTON 98168 Stepan & Associates 930 South 336th Street Federal Way, Washington 98003 JAN 141 Attention: Mr. Glenn McKinney Re: Water District No. 75 Comp Plan 1981 -1985 Dear Mr. McKinney: Please find enclosed a copy of Page 102 of Water District No. 75's current Comprehensive Plan. We show extending 3,800 lineal feet of 8" ductile iron main along Slade Way. This would loop our .facilities at 51st Avenue South and South 166th Street. Our existing 6" C.I. along South 160th Street could possibly be used depending on fire flow requirements for this development. Hopefully, this information is what you required. Please call me should you have any questions. Sincerely, -17244- Duane Huskey,'P.E. DH:tmw Enclosure cc: Ken Hall, Manager, WD #75 .+ TIMETARI.E OF IMPROVEMENTS A. The order of listing below is a tentative priority listing subject to change, based on a continuing evaluation of needs. B. The costs shown are estimated at 1981 prices. For each subsequent year prior to construction, an estimated lOX must be added to this coat due to inflation. It is thus recommended that an annual in- crease of 102 be made to the Replacement and Renewal Fend, in order to keep pace with increased construction costs. TABLE. 23 Replacements and Renewals - Immediate (1981 -1985) $380,000 /Year EST. 1981 ALONG FROM TO LENGTH SIZE COST *S. 166th St. 32nd Ave. S. 34th Ave. S. 1100' 8" . $ 24,200 S. 170th St. 40th Ave. S. 49th Ave. S. 2,700' 8" 59,400 *S. 170th St. 49th Ave. S. 51st Ave. S. 630'. 8" 15,100 S. 170th St. 51st Ave. S. 53rd Ave. S. 500' 8" 11,000 *S. 175th St. 33rd Ave. S. 34th Ave. S. 320' 8" 7,040 *S. 192nd St. Des Moines Way 16th Ave. S. 1,050' 8" 23,100 S. 208th St. Pac. Hwy. S. Military Rd. S. 2,300' 8" 50,600 *S. 236th St. 10th Ave. S. 13th P1. S. 730' 12 ". .24,090 Slade Way Slat Ave. S. 54th Ave. S. 3,800' 8" 83,600 6th Ave. S. Cul -de -Sac S. 200th St. 300' 12" 9,900 *33rd Ave. S. S. 170th St. S. 175th St. 1,740' 8" 38,280 42nd Ave. S. S. 160th St. S. 164th St. 1,300' 8" 28,600 *42nd Ave. S. S. 272nd St. S. 276th St. 1,315' 8" 28,930 42nd Ave. S. S. 276th St. S. 280th St. 1,300' 8" 28,600 *46th Ave. S. Star Lake Rd. S. 280th St. 1,290' 8" 28,380 *53rd Ave. S. S. 168th St. S. 170th St. 660' 6" 10,840 Military Rd. S. S. 224th St. Kent -Des Moines Rd. 2,700' 8" 59,400. *Bow Lake Tank Area Fressure Zone Modification 60,000 Subtotal $591,060 *1981 Projects 0 N JERRY P. HARRIS. President GEORGE EL. MBERG. Secretary DAN,CALC1AELL. Commissioner Water 21i/ric/ 71o. 75, Jan Counif 'eleorone 824 0375 January 4, 1985 KEN E HALL MARION HARTER P 0. Bo. 68100. Riverton Heignts Station Office 19863 22th Avenue So SEATTLE. WASHINGTON 98188 Mr. Brad Collins, Planning Director City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, Washington 98188 R. W. Thorpe & Associates 815 .Seattle Tower Third & University Seattle, Washington 98101 Re: Draft EIS, Valley View Estates 1984 Gentlemen: Highline water district intertie Water district 75 intertie Water district #75 intertie Water District No. 75 finds it highly impractical in view of the newly - passed Water System Coordination Act for the City of Tukwila to extend a dead end main into our corporate boundary to .serve property where the District has existing facilities. Our Comprehensive Plan contemplates looping our existing system from Slade Way along 54th Avenue South to connect to an existing line on S. 166th Street. We are not anxious to continue the flushing programs necessary for the existing dead end mains. Another dead end main installed using City of Tukwila facilities will only contribute to an existing bad situation. The District feels it may also be appropriate to discuss with Tukwila an intertie at the PRV facility on 53rd Avenue South. We do not desire this potential customer to withdraw from our corporate boundary, nor are we interested in a service area agreement to allow Tukwila to serve a customer we are better equipped to serve. • City of Tukwila Planning Department and R. W. Thorpe & Associates Page 2 January 4, 1985 We would be more than happy to discuss this project with the City of Tukwila Planning Department or the developer at their convenience. Please call Duane Huskey or myself should you have any questions. Sincerely, en Hall Administrative Manager KH:tmw cc: Dr. Herman Allenbach .Puget Western, Inc. .Paula Russell, Boundary Review Board COMMISSIONERS E w SVTTE.s SET'TT LIME U C.AEL J WEST AA.vUF SEWER OISTRICT 14816 MILITARY ROAD SOUTH P.O. BOX 68063 SEATTLE WASHINGTON 98168 TELEPHONE: 242.3236 • January 23, 1985 Brad Collins, Planning Director City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, Wa. 98188 MANAGER: JAN 2 81985 T J YATEL Cw COMMENT ON VALLEY VIEW ESTATES DRAFT EIS SUBJECT: Sanitary Sewers The comments made herein are in reference to the 12" sanitary sewer line owned and operated by the Val Vue Sewer District that traverses the proposed Valley View Estate site. The District and its consulting engin- eering firm, Yoshida, Inc., has reviewed the Draft EIS and the easement for the District's sewer line and has concluded that to case the sewer in those areas where buildings are to be built over the sewer may not be the best method or the most cost effective. Attached is a copy of the site utility plan (Figure 16) on page 130. The District's recommended method is to relocate a portion of the existing 12" sewer line. This is indicated in orange on the revised site utility plan. The relocation will eliminate the potential violation of the City's policy that prohibits placement of buildings on top of sewer lines. It will also eliminate the potential of a possible sewerage spill that could occur during the encasement of the sewer line. The relocation construction of the sewer line can occur without any disruption of service in the existing line. Should any further information or elaboration be required on this matter, please contact this office. Sincerely, VAL VUE SEWER DISTRICT i / T./MATELICH Manager TJM /gbs Enc. MEMORANDUM TO: DUANE GRIFFIN, BUILDING OFFICIAL FROM: PHIL FRASER, SENIOR ENGINEER 4' DATE: 7/26/89 RECEIVED JUL 2 8 1989 TRITEC ASSOCIATES INC. SUBJECT: PUBLIC WORKS REVIEW OF RAINIER RIDGE SOILS REPORT THE PUBLIC WORKS DEPARTMENT HAS REVIEWED THE 7/19/89 LETTER OF JOHN E. ZIPPER, P.E. OF RITTENHOUSE -ZEMAN & ASSOCIATES, INC. REGARDING THE PROPOSED RAINIER RIDGE APARTMENTS AT S. 178TH STREET. IN TERMS OF CONSTRUCTION OF UTILITIES AND TEMPORARY EROSION CONTROL ASPECTS THE FOLLOWING COMMENTS ARE PROVIDED: 1. THE SOILS REPORT SHALL SPECIFY MEASURES THAT WILL BE TAKEN FOR CONTROL OF ALL CONDITIONS OF SURFACE WATER AND UNDER- GROUND WATER ON SITE FOR TWO CONDITIONS: A) DURING CONSTRUCTION, AND B) AFTER CONSTRUCTION (PERMANENT FACILITIES, MAINTENANCE AND MONITORING PROGRAMS). 2. THE SOILS REPORT SHALL SPECIFY (THROUGH OUT YEAR) WHEN CONSTRUCTION WILL BE ALLOWED. (OR RESTRICTED) DURING THE YEAR. AND ALSO PROVIDE A RECOMMENDED PHASING OF CONSTRUCTION TO PROVIDE MAXIMUM CONTROL OF SURFACE WATER. PUBLIC WORKS RECOMMENDS THAT TO MINIMIZE THE, POTENTIAL OF SOIL EROSION DURING CONSTRUCTION: A. ALL TEMPORARY EROSION CONTROL FACILITIES BE IN PLACE AS FIRST ORDER OF CONSTRUCTION PHASE ACTIVITIES B. THAT EITHER ALL UTILITIES AND ROADWAYS BE CONSTRUCTED IN THE MONTH OF AUGUST, OR, THE TEMPORARY AND PERMANENT STORM DRAIN SYSTEM AND THE PARKING LOT PAVEMENT BE INSTALLED ALONG WITH "A" ABOVE AS FIRST PHASE OF THIS DEVELOPMENT CONSTRUCTION. WATER, SEWER AND OTHER UTILITIES CAN CUT INTO THE ASPHALT AND PATCH THE PAVEMENT SUBSEQUENTLY (PERMANENT PAVING WILL BE REQUIRED AFTER MAJOR CONSTRUCTION HAS COMPLETED ON SITE TO RESTORE DAMAGED PAVEMENT FROM CONSTRUCTION). DUE TO THE STEEP DOWNHILL SLOPE JUST EAST OF THE PROPOSED CONSTRUCTION AND DEVELOPMENTS AT THE TOE OF THIS STEEP BANK, ANY POTENTIAL EROSION TO THE HILLSIDE MUST BE ADDRESSED IN THE FINAL SOILS REPORT AND BUILDING AND SITE PLAN SUBMITTALS. PAGE 2 3. THE FINDINGS BY RZA AND DAMES AND MOORE ARE CONSISTENT. WE THEREFORE DO NOT RECOMMEND A FURTHER REVIEW OF THEIR WORK BY AN INDEPENDENT CONSULTANT FOR THE SITE.' PUBLIC WORKS PROVIDES THE ABOVE RECOMMENDATIONS AND TURNS THIS INFORMATION OVER TO THE BUILDING OFFICIAL, REQUESTING THAT YOUR OFFICE ADDRESS ANY CONCERNS YOU MAY HAVE REGARDING THE BUILDING FOUNDATIONS RELATIVE TO THE FINDINGS OF THE SOILS REPORT. ENCLOSURES (3) XC. ROSS EARNST RON CAMERON RAINIER RIDGE DEVELOPMENT FILE 40 BORING C .(CONTINUED) GRAPHIC TEST DATA LOG DESCRIPTION F LGURE A-3 45 - E1 w rL50� z a a 55-1 60- 65' 70" 75 61 4.3% 116.111 93 34.90 82.711 50 4" 26.0% 99.011 50 5" 26.6% 98.711 5.0 5 " 16.1% 119.211 89 6" 4.0 159.8 II 7.1% 60 6" ML GRAY GRAVELLY SANDY SILT TO SILTY SAND WITH SM WET FINE TO MEDIUM SAND LENSES (STIFF TO DENSE, MOIST) SM ML SM ML GM GRAY FINE TO MEDIUM SAND WITH SOME SILT, ORGANIC FRAGMENTS AND MICA.(DENSE, MOIST TO WET) SHOE CONTAINED WOOD GRAY FINE SANDY SILT (STIFF, MOIST TO WET) GRAY GRAVELLY SILT WITH FINE TO MEDIUM SAND LENSES AND OCCASIONAL ORGANIC FRAGMENTS (STIFF TO VERY STIFF, ;•101ST) . GRAVEL AT 64 FEET BORING COMPLETED AT 73i FEET ON 10/20/83 PIEZOMETER INSTALLED AT 733 FEET ON 10/20/83 GROUNDWATER LEVEL AT 64 FEET DURING DRILLING *SEE KEY FOR EXPLANATION OF SYMBOLS GeoEngineers Inc. LOG OF EXPLORATION w w 10 z a 15 20 25 30 35 BORING D ELEVATION: 178.8 FEET *GRAPHIC *TEST DATA LOG 9 26.6% 91.111 19 23.5% 100.911 32 18.8% 110.611 32 19.7% 110.911 50 1 GRAY SANDY GRAVEL (DENSE, WET) El 5" 9.6% 14 30.9% 88.811 36 29.6% 93.111 DESCRIPTION BROWN AND GRAY SILT WITH ORGANIC FRAGMENTS AND ROOTS (STIFF, MOIST TO WET) (FILL ?) FIGURE A -4 GRAY SILT WITH SOME RUST STAINS (STIFF, MOIST) LAMINATIONS DIPPING AT 20 °, OCCASIONAL CALCIUM CARBONATE CONCRETION GRAY SILT WITH POCKETS OF GRAY FINE SAND (STIFF, MOIST) OCCASIONAL GRAVEL WITH FINE SANDY SILT LENSES SLICKENSIDES 50 2" 6.4% 142.4® 40 *SEE KEY FOR EXPLANATION OF Sr4ROLS QAH:fMn:D.^ 40 BORING D (CONTINUED) *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -5 45 — w 50 - z F a ca 55 60 - 78 6" 7.3% 139.2 50 11.5% 50 4" 10.6% 130.8 100 19.7% GP GP GM GM GRAY SANDY GRAVEL WITH SOME SILT (DENSE, WET) GRAY SILTY SANDY GRAVEL (DENSE, WET) 7 FEET OF HEAVE AT 57i FEET BORING COMPLETED. AT 58i FEET ON 10/19/83 PIEZOMETER INSTALLED AT 581 FEET ON 10/19/83 *SEE KEY FOR EXPLANATION OF SYMROT.S GeoEngineers Inc. LOG OF EXPLORATION RAH'(MD:DA DEPTH IN FEET 0 5 BORING F ELEVATION: 237.0 FEET *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -6 10= 15- 20- 25- 30- 35- 40- 5 43.5% 70.911 7 35.0% 86.211 6 27.4% 96.111 14 27.0% 97.911 12 30.3% 93.811 • 35 30.6% 92.21 51 30.1% 92.511 65 24.3% 101.911 SM SM ML ML ML ML BROWN- BLACK -GRAY SILTY SAND WITH ORGANICS .(MEDIUM DENSE, MOIST TO WET) (FILL). GRAY SAND WITH MICA (MEDIUM DENSE, MOIST TO WET) GRAY FINE SANDY SILT (SOFT, WET) GRAY SILT WITH A TRACE OF CLAY WITH SLICKENSIDES AND SOME WET FINE SANDY SILT LAYERS. (MEDIUM STIFF, MOIST) GRAY SILT AND FINE SANDY SILT LENSES AND SLICKENSIDES (STIFF, DAMP) SLICKENSIDES GRAY FINE SANDY SILT WITH SLICKENSIDES (STIFF, DAMP) *SEE KEY FOR EXPLANATION OF SYMROLS GeoEngineers Inc. LOG OF EXPLORATION 0 • z -, 40 BORING F (CONTINUED) *GRAPHIC *TEST DATA LOG DESCRIPTION FIGURE A -7 45- a A 55-m 60- 65— 76 26.5% 97.311 34 20.6% 109.511 50 5 13.5% 122.611 ML ML SP 50 2" GM 9.1% 117.611 ML GM 50 11 SOME FINE SANDY SILT LENSES GRAY SILT INTERBEDDED WITH FINE TO MEDIUM SAND (STIFF TO DENSE, MOIST TO WET) INCREASING GRAVEL CONTENT WITH DEPTH GRAY SANDY SILTY GRAVEL TO SANDY GRAVELLY SILT (DENSE TO-VERY DENSE, MOIST TO' WET) GRAY SANDY SILTY GRAVEL (VERY DENSE, MOIST TO WET) BORING COMPLETED AT 63 FEET 1 INCH ON 10/21/83 GROUND WATER LEVELS MEASURED AT 10.5 AND 53 FEET DURING DRILLING INCLINOMETER CASING INSTALLED AT DEPTH OF 63 FEET 1 INCH ON 10/21/83 *SEE KEY FOR EXPLANATION OF SYMBOLS GeoEngineers Inc. LO(; OF EXPLORATION PAH:GMf DA 0 5 w 10- z a 15� 20- 25-' 30- 35- 40— BORING G ELEVATION: 179.2 FEET FIGURE A -8 *GRAPHIC *TEST DATA LOG DESCRIPTION SM BROWN GRAVELLY SILTY SAND WITH SOME COBBLES (MEDIUM DENSE TO DENSE, MOIST) BROWN AND GRAY RED - STAINED GRAVELLY SILTY SAND (MEDIUM DENSE, MOIST) 20 11.2% 105.011 20 25.9% 98.711 15 32.0% 90.311 25.7% 99.8 1 8 35.0% 86.511 18 32.3% 90.811 31 28.7% 92.71 57 27.7% 95.911 SM ML GRAY SILT WITH .FINE SANDY SILT LENSES (STIFF, MOIST) FINE SANDY SILT LENSES (MOIST TO WET) SLICKENSIDES DIPPING AT 45° FINE SAND LENSES GRADES TO VERY STIFF AND DAMP SLICKENSIDES SLICKENSIDES WITH FINE SANDY SILT LENSES *SEE KEY FOR EXPLANATION OF SY *+ROT.S GeoEngineers Inc. LOG OF EXPLORATION 40 BORING G (CONTINUED) *GRAPHIC *TEST DATA LOG 50- z F a 55 60 65 70 - 15 - 80— 32 25.1% 99.811 42 25.2% 100.311 21 24.8% 101.111 63 6" 24.0% 101.211 86 6" 12.4% 125.3 50 1" 13.7% 121.91g 70 6" 26.3% 99.411 50 25.3% 96.5 ML ML SP SM GM SP .DESCRIPTION HIT GRAVEL AT 45 FEET FIGURE A -9 -GRAY SILT WITH FINE SANDY SILT AND FINE TO MEDIUM SAND LENSES (STIFF,.MOIST) SLICKENSIDE GRAY' FINE TO MEDIUM SAND WITH GRAY SILT INTERBEDDED (MEDIUM DENSE, WET) INCREASING GRAVEL CONTENT GRAY SILTY SANDY GRAVEL (.DENSE, MOIST TO WET) 2 FEET HEAVE AT 67.5 FEET GRAY FINE TO MEDIUM SAND WITH SOME GRAVEL AND OCCASIONAL GRAY SILT LAYER (DENSE, WET) BORING COMPLETED AT 78i FEET ON 10/18/83 GROUND WATER LEVEL AT 49i FEET DURING DRILLING PIEZOMETER INSTALLED AT 78' FEET *SEE KEY FOR EXPLANATION OF SY>wgOLS GeoEngineers Inc. 1 LOG OF EXPLORATION 141 111 RZA • • Letter of Transmittal RITTENHOUSE-ZEMAN & ASSOCIATES, INC. Geotechnical Consultants 1400 140th Avenue N.E. Bellevue, Washington 98005 To: /(/2 P414mi;y 62oo _SCA IACe14--- I 1 A / a-p.--641e0--t` a/vee. 96/88 4H74 ' Verzt 004 e-{ IA } OCT - 3 1989 Date: By: )I1ka Job No.: Project: Re: 2a4ijec-- fe _b /6/00fe 7e&r -- We are sending you: VAttached 0 Under separate cover Cof ) o /tio.). 2 5, 5'7 0 For your information & use ifF)As requested 0 For review & comment ,O As noted 0 Copy to: I 6r,ed/r7c& If enclosures are not as noted please notify us at once. ;�tt' CG ' ti7 11 . C7 NILLIHI'I I ULK 2k H5SUL oft ES e • cso CON1u11AN ?L IN ThL LNVI'QNM• ..NI ANq 111■110tr toAIN P.2 /3 ..... •. .....•r..t:•...... • 1 •t.t• .$.,•. 4 WO to. • 1/AMLOVVL • 11JPTC SOO.NQATMGATC Vitetmuit CENTCA /• IS6 N C SO(' • STACEY • SCITTlC,WASNINa70N 9445 • IaoeY Sl3'o564 • CAe1,C: c,AMEMOMr / / Twat: 6•0••44• ?G: • I November 29, 1976 McCann Development Corp. 9S0 Andover Park East • Suite 10 P.O. Box 88314 - Tukwila Branch Seattle, Washington 98188 Attention: Bruce E. McCann Gentlemen: We have inspected the hillside area to the west of Southcenter Parkway and north of South 178th Street on November 29, 1976. The slopes in this area were formed by Borrow Pit excavation made in 1966. Since that time, vegetation in the form of grass, blackberry vines and alder trees have cover the slopes. Our inspection indicates no evidence of major slope instability. There is a small sloughing of the toe of the slope along the rail spur which serves the Levitz Furniture building. However, this . is the only indication of movement at this time. Inspection of the trees.on the slope show some.superficial creep which occurred at the time the vegetation was taking root. The attitude of the•trees indi- cates stability of the hillside over the past several years. We understand that you propose to develop the properties that exist on two relatively level areas, one a short distance upslope and to the southwest of the planned RB Furniture Store and the other on the bench at the crest of the slope west of the Levitt Furniture building and immediately east of the 1 -5 right -of -way. Construction on the lower slope would comprise commercial buildings, one or two stories in height. The structures on the upper bench would be apartments. It is our opinion that both sites will satisfactorily support the proposed construction without adverse affect on the stability of the hillside. For the most part, we anticipate that the loads imposed by these structures will be less than the overburden pressures of the soils which have been previously excavated to form the existing leve], areas. r. • rage Two November 29,1976 1 In summary, our inspection of the hillside arras indicates that it has performed as expected on the basis of our investigation i made on this property in 1965. Very truly yours, U AND MOORE J KT /mm Four (4) copies submitted icAgL, //7271&--- k K. Tuttle ,. rtner 00 0 THE NOLLY CORPORATION 101 East 26th Street - Suite 301 • Tacoma, WA 98421 • (206) 627 -5800 September 22, 1989 L. Rick Beeler, Planning Director Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Subject: Rainier Ridge Apartments - EIS Scope Response EPIC 33 -86 Dear Rick: SEP 27 1989 This letter is intended to serve as our formal response to your E.I.S. Scoping Notice on our apartment project dated June 8, 1989. For clarity, our response format mirror's that of the Notice. ALTERNATIVES TO BE EVALUATED IN THE DEIS We agree. ELEMENTS OF THE ENVIRONMENT A. Earth We believe this section has been replaced by the Fraser - Griffin letter dated July 26, 1989, attached. B. Air Quality We agree. C. Water We agree. D. Noise We agree. E. Aesthetics We agree. F. Transportation Public Works has been provided all traffic analyses for this property. We feel this information can either be incorporated into the EIS, or the scope be reduced based on this information. G. Utilities We disagree. The City needs to respond to the Betlach - Earnst letter dated July 28, 1989, attached. I can be contacted at the above number if you have any questions. rely, k La enc cc: Bruce McCurdy, Southcenter Gateway Associates attachments Citf Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 • DATE /TIME• FAX TRANSMISSION SEPTEMBER 21, 1989 TO: (Name) BILL BETLOCK (HOLLY HOMES) (Company Name) 272 -5591 (FAX #) FROM: VERNON UMETSU - CITY OF TUKWILA FAX #: 433 -1833 DEPARTMENT OF COMMUNITY DEVELOPMENT PHONE NO: 433 -1858 SUBJECT: EIS SCOPE - RAINIER RIDGE APARTMENTS PAGE(s)• 11 (+ Cover Sheet) COMMENTS: 00 0 THE tiOLI.Y CORPORATION 101 East 26th Street - Suite 301 • Tacoma, WA 98421 • (206) 627 -5800 September 18, 1989 L. Rick Beeler, Planning Director Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Subject: Rainier Ridge - E.I.S. Decision SEP 191989 CITY The purpose of this letter is to formally notify you that we have reached a decision to proceed with the Environmental Impact Statement process for our Rainier Ridge Apartment project. To expedite this process we recommend R.W. Thorpe and Associates, Inc. be retained as the E . I . S . Consultant. To initiate finalization of the consultant selection process, we have requested R.W. Thorpe and Associates, Inc. to prepare and submit a Statement of Qualifications to you. I will contact your staff to work out the details on this project. Since ely, / Wi i- B. Betlach Project Manager cc: Rick Lawrence, The Holly Corporation Bruce McCurdy, Southcenter Gateway Associates Riley Evans, TRITEC Associates, Inc. Jon Potter, R.W. Thorpe and Associates, Inc. City Tukwila • 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor August 17, 1989 Bill Betlach Tritech Associates, Inc. P.O. Box 1914 Tacoma, WA 98401 RE: Rainier Ridge SEPA Threshold Determination (EPIC- 33 -88) Dear Mr. Betlach, I have reviewed the project modifications, additional soils data and Public Works Department comments in reconsidering my Determination of Significance (April 10, 1989). I find that there continue to be possible significant environmental impacts and hereby reaffirm the requirement for an environmental impact statement. Draft environmental impact statement contents would continue to be as outlined in the City's letter of June 8, 1989. Upon confirmation that you will continue, the City will negotiate a total D.E.I.S. cost and prepare a consultant contract. Consultant work will be authorized upon receipt of your check for this total cost. F.E.I.S. costs will be established after comments have been received. My rough estimate to complete SEPA is five to seven months, exclusive of any appeals. Please inform Vernon Umetsu of your project development intentions by September 6th. Alternatively, my decision may be appealed to the Tukwila City Council within 10 days of this letter pursuant to TMC 21.04.280. Sincere vt.. Rick - , SEPA Responsible Official 70 ,:t eds1 1.7c, re4 7P0 July 28, 1989 Kim Hart Tukwila Finance Dept. Dear Kim, Please refund the Holly Corporation their total escrow amount of $500.00 deposited on March 23, 1989 (Rec. No. 8488). TRITEC • ASSOCIATES INC. P.O. BOX 930 SILVERDALE, WA 98383 (206) 692 -6400 P.O. BOX 1914 TACOMA, WA 98401 (206) 572 -6400 July 28, 1989 Ross Earnst, P.E., Director City of Tukwila Department of Public Works 6300 Southcenter Boulevard Tukwila, WA 98188 Subject: Rainier Ridge - Sewer Availability Dear Ross: The purpose of this letter is to confirm sewer availability for the above referenced project. The subject property is generally located within the northeast quadrant of the intersection of I -5 and S. 178th Street (see site vicinity map, attached). The previous owners of the site, Sammamish Commercial Co., (William Polk, Trustee) constructed the sewer system along Southcenter Parkway in the mid 1960's as a portion of the improvements required for construction of the Southcenter Industrial Park project. The subject property represents a portion of the approximate 160 acres included in the Southcenter Industrial Park project. Anticipated flows from the property were included in the calculations utilized in pipe sizing. Following construction, responsibility for operation and maintenance of this line was transferred by deed to the City of Tukwila. Additionally, in anticipation of future development, an easement for extension of the system was reserved from the WSDOT energy dissipation device, across the Levitz furniture parking lot, to Southcenter Boulevard. As we understand, the above has been confirmed in discussions between you and Harold Iverson. Mr. Iverson is president and founder of the Sammamish Commercial Co. We have discussed this with Phil Fraser of your department. We have mutually agreed that this letter will serve as the formal mechanism to bring this issue to resolution. Page 2 Ross Earnst July 28, 1989 Based on this information, we respectively request the City sign and return this document to our Tacoma office. I can be contacted at (206) 572 -6400 should you have any questions, or require additional information. Sin rely, Wi 1 i. B. Betlach P oject Manager The City of Tukwila concurs that sewer availability to the subject property is hereby approved. City of Tukwila Date attachment cc: Phil Fraser, City of Tukwila Rick Lawrence, The Holly Corporation Bruce McCurdy, Southcenter Gateway Associates Barbara Headley, The Holly Corporation MEMORANDUM TO: DUANE GRIFFIN, BUILDING OFFICIAL FROM: PHIL FRASER, SENIOR ENGINEER DATE: 7/26/89 SUBJECT: PUBLIC WORKS REVIEW OF RAINIER RIDGE SOILS REPORT THE PUBLIC WORKS DEPARTMENT HAS REVIEWED THE 7/19/89 LETTER OF JOHN E. ZIPPER, P.E. OF RITTENHOUSE -ZEMAN & ASSOCIATES, INC. REGARDING THE PROPOSED RAINIER RIDGE APARTMENTS AT S. 178TH STREET. IN TERMS OF CONSTRUCTION OF UTILITIES AND TEMPORARY EROSION CONTROL ASPECTS THE FOLLOWING COMMENTS ARE PROVIDED: 1. THE SOILS REPORT SHALL SPECIFY MEASURES THAT WILL BE TAKEN FOR CONTROL OF ALL CONDITIONS OF SURFACE WATER AND UNDER- GROUND WATER ON SITE FOR TWO CONDITIONS: A) DURING CONSTRUCTION, AND B) AFTER CONSTRUCTION (PERMANENT FACILITIES, MAINTENANCE AND MONITORING PROGRAMS). 2. THE SOILS REPORT SHALL SPECIFY (THROUGH OUT YEAR) WHEN CONSTRUCTION WILL BE ALLOWED (OR RESTRICTED) DURING THE YEAR. AND ALSO PROVIDE A RECOMMENDED PHASING OF CONSTRUCTION TO PROVIDE MAXIMUM CONTROL OF SURFACE WATER. PUBLIC WORKS RECOMMENDS THAT TO MINIMIZE THE POTENTIAL OF SOIL EROSION DURING CONSTRUCTION: A. ALL TEMPORARY EROSION CONTROL FACILITIES BE IN PLACE AS FIRST ORDER OF CONSTRUCTION PHASE ACTIVITIES B. THAT EITHER ALL UTILITIES AND ROADWAYS BE CONSTRUCTED IN THE MONTH OF AUGUST, OR, THE TEMPORARY AND PERMANENT STORM DRAIN SYSTEM AND THE PARKING LOT PAVEMENT BE INSTALLED ALONG WITH "A" ABOVE AS FIRST PHASE OF THIS DEVELOPMENT CONSTRUCTION. WATER, SEWER AND OTHER UTILITIES CAN CUT INTO THE ASPHALT AND PATCH THE PAVEMENT SUBSEQUENTLY (PERMANENT PAVING WILL BE REQUIRED AFTER MAJOR CONSTRUCTION HAS COMPLETED ON SITE TO RESTORE DAMAGED PAVEMENT FROM CONSTRUCTION). DUE TO THE STEEP DOWNHILL SLOPE JUST EAST OF THE PROPOSED CONSTRUCTION AND DEVELOPMENTS AT THE TOE OF THIS STEEP BANK, ANY POTENTIAL EROSION TO THE HILLSIDE MUST BE ADDRESSED IN THE FINAL SOILS REPORT AND BUILDING AND SITE PLAN SUBMITTALS. • • PAGE 3. THE FINDINGS BY RZA AND DAMES AND MOORE ARE CONSISTENT. WE THEREFORE DO NOT RECOMMEND A FURTHER REVIEW OF THEIR WORK BY AN INDEPENDENT CONSULTANT FOR THE SITE. PUBLIC WORKS PROVIDES THE ABOVE RECOMMENDATIONS AND TURNS THIS INFORMATION OVER TO THE BUILDING OFFICIAL, REQUESTING THAT YOUR OFFICE ADDRESS ANY CONCERNS YOU MAY HAVE REGARDING THE BUILDING FOUNDATIONS RELATIVE TO THE FINDINGS OF THE SOILS REPORT. ENCLOSURES (3) XC. ROSS EARNST RON CAMERON RAINIER RIDGE DEVELOPMENT FILE tRITEC • ASSOCIATES INC. P.O. BOX 930 P.O. BOX 1914 SILVERDALE, WA 98383 TACOMA, WA 98401 (206) 692 -6400 (206) 572 -6400 • July 19, 1989 Phil Fraser, Senior Engineer City of Tukwila Department of Public Works 6300 Southcenter Boulevard Tukwila, WA 98188 Subject: Rainier Ridge - Soils Review Dear Phil: As discussed with you, the purpose of this letter is to formally request the City initiate the necessary actions to perform an in -house review of the geotechnical report prepared by Rittenhouse - Zieman & Associates, Inc. (RZA) March 23, 1989. This information was previously submitted to the City April 3, 1989 as a portion of the SEPA review. Our goal is to rescind a previously issued Determination of Significance on the same property, dated April 10, 1989. This determination was issued on a commercial multi - family project consisting of 108 units. We have significantly revised the project, proposing a 70 unit project wlrich'will be setback from the top of slope approximately 15 feet. This revised site plan was presented to Vernon Umetsu, Planning, in a meeting held at the City on June 26, 1989. As the scope of the project has changed significantly, our belief is it is no longer necessary to have a third party review conducted by a geotechnical engineer under contract to the City. This project has been reduced to a standard multi - family commercial project situated on standard soils capable o supporting the project, therefore requiring standard City review processes. To substantiate this conclusion, we have requested RZA to prepare additional information which is intended to address elements of the EIS scoping notice issued for the 108 unit project June 8, 1989, with our revised 70 unit project. This information is enclosed for your review. Additionally, please find enclosed a copy of the revised 70 unit site plan for the project. Thank you in advance for you timely response. 1 can be contacted in our Tacoma office at 572 -6400 should you have any questions. Si erely, Wil a B. Betlach Project Manager enclosures cc: Ross Earnst, Public Works Director Vernon Umetsu, Planning Rick Lawrence, The Holly Corporation Bruce McCurdy, Southcenter Gateway Associates R177 TRNROU EMAN AssocutTES, INC. CcoiJchmlcal nvironmental Consultants 14001 40th Avenue N.B. r Belle(ue, Washington 980054594 (206);746 -8020 /FAX (206) 746 -6364 19 July 1989 The Molly Corporation P.Q. Box 999511 Tacoma, Washington 98499 Attention: Mr. Jerry Flensburg Subject: ■esponse to Tukwila Planning Department otter of 6/8/89 - Jainier Ridge Apartments Tukwila, Washington Gentlemen: • W -5873 As requested, his letter presents additional geotechnical information for the referenced project. This I tter responds to comments in the City of Tukwila Planning Department letter regardin EIS scoping dated June 8, 1989. The information In this letter is based upon subsurfe1e explorations completed at the site for our fwo previous studies, es well as a conceptu I development plan dated 26 June 1989 by Berry & Berry Associates, Item C of the r ferenced letter indicated that compressed organic material encountered in Boring B -1 a 38 -feet depth is perceived to indicate a potential problem. The geologic profile of borin B -1 indicates that the compressed organics are overlain by at least 33- feet of very de se, glacially consolidated soils. Due to the compressive effects of the thick glacial is mass which deposited and subsequently consolidated the soils, the compressed organics encountered in the boring consist of a brittle, dark brown, remnant of a stick or log, which has been compressed to roughly 1 /8 -inch thickness. These types of compr ssed organics are in glacially deposited soils as encountered at this site. Similar materie s were present below the foundation of the 42 -story First Interstate Center and the nine story Virginia Mason Medical Center north campus addition. The presence of th se materials within and below glacially consolidated soils will have no effect on sett ement performance of the structures or foundations. Since the The Holly Cor oration. 10 July 1999 W -5873 Page 2 concenptual development plan indicates that buildings would be located above the existing slope, with a minimum 15 -foot setback, it is our recommendation that typical spread tooting be utilized to support the structures. Compact, glacially consolidated soils are Ares nt at relatively shallow depths throughout the area of the proposed development, s indicated in our previous reports. Additional borings are therefore not required, In ou opinion, for foundation and building design. The boring log Indicate groundwater conditions observed during the drilling. The date of groundwater( observation Is Indicated on every exploration log. As described in the previous repots, groundwater present on the site Is perched within granular materials, typically above a layer or lnterbed of lower permeability. Since the perched groundwater conditions do of represent an aquifer of significant size or quantity, there would be little effect on the d velopment. The site's proximity to steep slopes provides a natural outlet for such perch groundwater zones, thereby preventing buildup of groundwater to high elevations. Th1 observed stability of the hillside since its original excavation indicates that the groundwater has little effect on slope stability. Perched groundwater is typically encountered w thin geological deposits such as those on this site, and if encountered within the area of proposed construction Is anticipated to be of limited quantity and extent. The Tukwila Pie nning Department letter refers to a "conclusion of no unstable soils in the immediate vicl9ity ". The report did not make that conclusion, but did indicate that we observed no eYII' idence of deep seated slope instability. This Is consistent with a prior inspection of the property by Dames & Moore in 1976. A copy of a letter written by Dames & Moorf , dated November 29, 1976, is attached, describing their observations of the site at that time. Both our report and the prior Dames & Moore inspection did observe some vidence of minor surficial soil movement near the toe of slope. With the structures set b ck at least 15 -feet from the existing top of slope, and with all foundations bearing on and sturbed, dense glacially consolidated soils, minor surficial soil movement on the toe or fahe of the slope would not affect the performance of building foundations. The proposed evelopment would not have an effect on the surfieiel soil movements, or on deep seats slope stability. The loads imposed by the structures will be insignificant compared to the weight of soils present within the slope, or the weight of the glacial ice mass, and would not present a driving force for potential Instabilities. It would appear The Holly Oor oratlp P 19 July 1989 that professlc major, deep An analysis o this proposed • W -5873 Page 3 nal opinions by two geotechnical consultants indicating no evidence of eared slope Instability would be sufficient to address the city's concerns. all downslope areas to South Center Parkway would not be Applicable to development. The Planning Department letter mentions "highly erodible soils onsite" several times, and indicates that he geotechnical report formed the basis for this classification. Our firm did not classify thF site soils within the proposed development area as "highly erodible ". We did, however,, provide erosion protection recommendations in the report which are prudent and Lommon for development adjacent to slopes of this magnitude. The greatest risk f erosion would have occurred with disturbance and exposure of silty sands underly ng the glacial till on the slope. The conceptual development plan requires no disturbanc of soils below the break In slope. Temporary erosion control facilities during eonstr fction are typically subject to County and City review and oversight and In our opinion, such measures would be relatively straightforward on this site. With the Structures set [ack at least 15 -feet from the existing top of slope, all temporary surface water can be livened during Construction, and permanent surface water runoff can be tight lined away from the slope to an appropriate storm drain. In summary, i# is our opinion that geotechnical information requested In the Tukwila Planning Department letter of June 8 1989 has already been addressed in our previous geotechnical rrports for the project. We feel that some of the comments do not apply to the presently proposed development which places all buildings at least 15 -feet back from the existing to of slope. We find that the letter refers to several Interpretations of Information in t e referenced geotechnical reports which we do not agree with. We also find that comp rlson of this property to unstable slopes (Le. Valley View Apartments and Sylvan Glen A artments) Is not valid due to the nature of the very dense, glacially consolidated s ils present on this site. The slope was excavated during the 1960's, and has subsequently been evaluated by our firm and Dames & Moore, who both found no evidence of ma or slope instability. It Is therefore our opinion that additional peizometric information, or slope stability analyses down to South Center Parkway, are not warranted. • The Holly Cor ration • W-5873 19 July 1989 Page 4 We appreciate his opportunity of continued service to you on this project. Please feel free to call if yo have any questions or need additional Information. Respectfully su mated, RITTENHOUSE•ZEMAN & ASSOCIATES, INC. of,e.ea tt) 1,.• John E. Zipper,'P.E. Associate O ,AN 2#3 PO Attachment: Dames 8I Moore letter dated 29 November 1978 cc: Tritec AssocIat:s Inc. /Mr. Bill Eetlach ri.Y w ^`S. f 11n.' ^S;J% 727 g ►, •1: 1 .al.R����,C!� t.tt:t.+• -•' 1.1;..71 */ ,!`F, •, :''tif.... 'uCIT %kf..'t, wfip. ,,. IS1yH !.•1i % 'l• df• ■ ' 0:Irr, )aialap on Corp. 07,o A s er P* 't tint - gtr i t:.w i.G r.o, p:7,1 eS314 - Tukwila Brareh Brace B. t!aCesnr. Centlonta: w5s-)3-I,. Wt! hsy :Tspeo c the ht1i iida errs to the w�1 t. vf, 4ouutzcootcr P ri-N ':r tend Rp Lh of ,?ath 178th Street co ?IC`-'eTt' I. t°.', )S7�. iY 5:0r.r.'i in thit 1 area ware fo?m,ed by ko, ro Pit t4::ciiVA13tsa: �r;.z�-;• In, 1f6f 5:r, :s Viet time vegetlt. In ti'' 0:11 0 gr,at2s, D,l.►Y: •y :: :: vine• And eldet tte'es h v1 rover til? ,c)c ts. cur tnupec t i rn indic.at t5 ba a vi dc&nele of ma) 0r s 1opa ins r.:; . T : v . beet )s a 1*1.et1 slo i bLna of the tce et the $ loa!et uluit ' '.Ii' i a l ipvv which :;7.i' eg the Lsv tz FurDiture bai diAg. Howeee1'_ t.;7:, is the only in ration of nuvertint et this rig,. 'rl$pe; :..:,r trees on the s o n ehow s,imc s'.spert i cx e l oToep which otc1441 •r ' time the vegttlitivn wet tskint rocs. Inc attit,,i:3a si tiw tttl Sttbllir.' o.f the h11istde oycr t;te yset S�tv�`:'iai y;s�., . 'e'T unt erttead het you propwA to develop th-s propert,'t tsi.'..; .?:::...t o:: t+f" re]at!v ly level artas, "re 2 short di t't9nc:: U[. iupt 2,.1 :. . the sturhueat f the plar.r.ed Rat f:Urnitere Sure arld the otht ;: r.r; t::..:, hanCl It the a gift Of the ti •! we8t of the Levitt i ".frnItLir :1.!, ..31 z :Lill ? h ..,,:ate;' e44t of t!',s Y.5 right- of =wa >'. Cor!itraLtiil t.,i m. . " 1::;p ^_ wee icy a ^.AInTi2ve ::_ aniercia1 bu.i1dings, one Of yWO :- .:f'1i, '..I. Th strrrudture4 on the 1.11,sr bench woul,3 to a er.w.e.s•t... -.,.rr opth om th.>st both sitst 0.i1 saticfatreti;y s1 ,j r :rs . >:. . toner- t!etitalt Without p►Sv,,r:.e n[fwtt ar the atb:;'_iS ti . .. - •e .i 119 i,i• . For the moat part., ' ^Y g�.ci,7iprt t that r,?�,e i.d:�.:�;5t .;:c,-.... 'Jv Ltetit V-C1 :SC 11741 VW. hR *m." th3. :' thq' eva A,41, 4.ri pit,cp •a : ;:t, sons w'..it h ha a burn p.e'w16ual.1 e!at"- a:•#tai to foray the kY.711 .. 1.6Vdi .1.666. t 3 ry, `IrA Wfor rtr:1 thls J ;11;;.1. (4', toni • • r Joliqtxicr tot Ihe 1.r.c;sm 1.na; Z;o ■eti 4t exptivtii vhz ci ear 1 Ircloorty 1L 196S. Vorryy ti.w)y ....*i..,...-.... intrt.7.;.5, ANI) ,t ( 7,.... h..4...,-1...- c.", . —...,,,...:.,., • F'' ° Ce:ttrtnct. • City eT Tukwila PUBLIC WORKS DEPARTMENT 6300 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -0179 Ross A. Earns, P.E. Director M E M O R A N D U M TO: Phil Fraser /Vernon Umetsu FROM: Ron Ca1n rb! , City Engineer DATE: July 7, t989 SUBJECT: Rainier Ridge Soils Phil Betlach of Tritec called about soils. He explained the conference call o:a: Holly Corporation, himself and Vernon. Per DRC explanation, ther *::..'z a new site plan and their questions is how to get soils and ti: is approval for DNS. The steps are: 1. Tritec will have their soils engineer, RZA review revisited site plan relative to soils and submit comments to Vernon. 2. We will (Phil, Vernon, myself) review that and establish the scope for Dames and Moore review of soils - stability, erosion control, surface water, etc. 3. Dames and Moore does their review and provides recommendation for approval, mitigations, controls. 4. We review, establish requirements to be given to Rainier Ridge /Tritec. 5. Provide that information to Rainier Ridge. These are the steps/we talked about at DRC and with Phil Betlach. xc: Rainier Ridip Development File D12 RAINIER.RDG „City tAkTukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor June 12, 1989 Bill Betlach Tritech Associates, Inc. P.O. Box 1914 Tacoma, WA 98401 RE: Rainier Ridge Project Meeting of June 12, 1989 Dear Bill: This letter is to review and expand on our meeting this morning. I have grouped the subjects into six general areas. 1. Simultaneous Permit Application The City of Tukwila allows the simultaneous submission and evaluation of the required environmental checklist (SEPA), the Board of Architectural Review (BAR) design review application, and the building permit application. The normal permit application process is a sequential application for SEPA and design review; followed by a building permit application to construct the approved project. Simultaneous permit application is at the applicant's option and full risk; in the knowledge that changes due to a set of criteria for one permit may require: changes to the project as a whole, revisions, extra costs, and lost time. No exemption from the provisions of any Code requirement or standard is implied or justified as a result of simultaneous application submittal. 2. Building permit status and time frame The Uniform Building Code (UBC) specifies a 180 day period within which to complete all work necessary to issue a building permit. Only a single extension of 180 days is allowed to this period, at the sole discretion of the Building Official should he determine that there is good and sufficient reason to grant it. The Planning Director has determined that the six to nine months required for completion of an environmental impact statement (EIS) and resolving any appeals should be outside the scope of the UBC plan check time frame. Therefore, the 180 day clock is suspended at the point where a determination of significance is issued and while you are actively pursuing completing SEPA requirements. Bill Betlach June 12, 1989 Page 2 The time between building permit application (12- 22 -88) and issuance of the Determination of Significance (4- 10 -89) when alternative project designs were produced, additional information was submitted and City staff evaluated the project is considered to be part of the normal plan review process. It shall be counted against the 180 plan check time. 3. Environmental Impact Statement Time Frame In general, the Director has determined that a reasonable SEPA process for Rainier Ridge should not exceed six months from the completion of EIS scoping. The Director, at his sole discretion, shall determine when the applicant is not actively pursuing the completion of SEPA requirements. The following project schedule represents a maximum time to complete SEPA: 06/26/89 Applicant submits project alternative(s). Applicant establishes a minimum $1,500 escrow fund to pay for consultant modification of EIS scope if necessary. 07/15/89 Contract with EIS consultant signed. All required escrow funds deposited with City by applicant. Consultant has completed EIS scoping on a time and materials contract. 09/01/89 Preliminary DEIS submitted for City and Applicant review. 10/02/89 DEIS completed. 11/15/89 DEIS public comment period completed. 12/15/89 Preliminary FEIS submitted for City and Applicant review. 01/02/90 FEIS completed. 01/15/90 FEIS appeal period completed. Remainder of 180 UBC plan check period resumes. Project is scheduled for the BAR. 4. BAR Design Review Time Frame Please note that the UBC plan check period is not suspended during BAR review unless the BAR decision is appealed to the City Council. The time frame for BAR review is considered Bill Betlach June 12, 1989 Page 3 to be reasonably included within the building permit review process. 5. Application. Action a. It is my understanding that the development team will be reviewing the proposed project in light of the information produced during EIS scoping and will propose a modified project design by June 26, 1989. The City's SEPA review should be suspended until this modified design is presented. b. An escrow fund of at least $1,500 shall be established immediately upon submittal of the project modifications for the purpose of revising the EIS scope should an EIS continue to be necessary and revision to the scope seem appropriate. 6. City EIS Review Procedure a. Any new EIS scoping changes resulting from project modifications shall be completed by a City consultant who is funded by the applicant per items 3 and 6b. Applicant billing shall be on a time and materials basis. b. The Director or his designee may determine a lack of determined effort by the applicant to complete SEPA should the promised project modifications not be submitted by June 26th. This would result in starting the UBC plan check review period. Please contact me at 433 -1858 if you have any questions regarding the above matters. Sincer y, ernon M. u, Associate Planner L. Rick Beeler, Director Department of Community Development City of Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 June 8, 1989 William Polk William Polk Associates 1201 Western Avenue Suite 410 Seattle, WA 98101 RE:. E.I.S. Scoping for EPIC 33 -88. Coordinated Permits: 89 -1 -DR, and CN -88 -393 through 398 (Rainier Ridge Apartments). Dear Mr. Polk, I have reviewed the environmental checklist, comments received during the E.I.S. comment period and considered additional information contained in the building permit application. A limited scope E.I.S. is required which addresses the areas of Earth, Air, Water, Noise, Aesthetics, Transportation, and Utilities. The contents of these sections shall clearly evaluate existing conditions, project impacts, mitigating measures and unavoidable adverse impacts in light of the City's comments below. Additional analyses necessary to resolve several issues shall be completed and incorporated into the D.E.I.S. Please note that you will be required to virtually complete geotechnical and structural engineering as part of SEPA review, to assure that the steep slope and soils can support the construction and structures. ALTERNATIVES TO BE EVALUATED IN THE DEIS 1. The proposed action. 2. All units pulled off of the eastern steep slope as presented earlier to the City. 3. Some reduction in the number of buildings. Density may or may not be reduced. Schematic concepts to be submitted for City approval. 4. No Action. A description of Project Alternatives 2 and 3 will be provided to the same level of detail as the proposed action including, but not limited to the following areas: plan view, elevations, cross - sections, and grade and fill plan. Mr. William Polk June 8, 1989 Page 2 ELEMENTS OF THE ENVIRONMENT A. Earth Discussion based on the geotechnical report, Dames and Moore revisions, and the following revisions to the SEPA checklist: a. Terrain is generally steep slopes with a bench; not rolling. b. Steepest slope is 1.67:1 (60 %); not 2:1 (50 %). c. Boring B -1 shows compressed organic and silt layers at 38 feet. This indicates variable soil conditions and the potential need for additional borings to determine depth to compact soils. The need for additional borings at each pile and structural support facility location shall be evaluated. Insufficient data is provided in boring Togs. Additional data required includes providing piezometric information for groundwater and sampling date. d. No data has been submitted to substantiate a conclusion of no unstable soils in the immediate vicinity. Such a conclusion is inconsistent with the geotechnical finding of highly erodible soils on site, and City experiences with unstable slopes on similar, nearby sites (i.e. Valley View Apartments, and Sylvan Glen Apartments). A geotechnical study and structural engineering analysis will be required to evaluate site stability under existing and proposed conditions. An acceptable engineering safety factor shall be specified and compared with the alternatives This analysis shall include all down slope areas to the Levitz railroad spur and Southcenter Parkway. The City will have Dames and Moore evaluate all geotechnical /hydrological studies pursuant to the scope in Attachment A. Their evaluation shall be incorporated into the DEIS WSDOT evaluation of the project alternatives should be included as applicable. This shall include, but not be limited to impacts and mitigating measures surrounding the storm water line running across WSDOT property and into their system. e. Cross - sections primarily running east to west, will be required to show existing and finished grades, and improvements for all alternatives. All retaining wall and rockeries (max. ht. is 4 ft.) shall be shown. Cross - sections shall show the site at a minimum 30 ft. scale. A second set of smaller scale cross - sections shall show the site, existing and finished grades, and alternative improvements in relation to the remaining down slope area to the Levitz spur and Southcenter Parkway. Mr. William Polk June 8, 1989 Page 3 f. The highly erodible soils on site (per Geotech. Rept.) indicates a high erosion potential during and after construction. Additional information on erosion control facilities and implementation schedule must be submitted. At a minimum, this shall include evaluating the need for the following development phasing: i. Acquire easement to construct/maintain /repair the storm water line from the property boundary to WSDOT storm water system and construct storm water line with no detention on site to the maximum extent feasible. Any detention facilities required by WSDOT should be constructed down slope on the flats where failure would not be as catastrophic. If on -site detention is feasible, the engineering design safety factor shall be specified and approved by the Public Works Department. Specific recommendations shall not be limited to actual facility requirements such as double walled detention pipes and a regular monitoring schedule. ii. Build temporary on site storm water construction and erosion control systems. g. iii. Complete on -site road system including curbing. iv. Complete all upslope improvements with immediate connection of roof drains to storm water system prior to start of down slope construction. This would minimize exposed erodible soils and runoff. An "as built" certified survey by a City selected surveyor on the eastern road curb and building foundation locations shall be required prior to starting work on eastern units. v. Phased construction of down slope units as possible. Phasing and construction practices to be per geotechnical study and as approved by the City. At a minimum, construction phasing will probably prohibit disturbing areas 20 ft. west of the existing eastern slope edge until all up slope structures and roads are completed. vi. All drainage facilities shall be sized for the 100 year event from the site to a public storm system. B. Air Quality Evaluate the long term air quality impacts from freeway originated pollutants, if any. If none, substantiate with a discussion. Mr. William Polk June 8, 1989 Page 4 C. Water • • a. Storm water runoff will be increased from its current undeveloped condition and diverted into a WSDOT system. WSDOT approval, the storm water line easement, and maintenance provisions must be documented in the E.I.S. b. Assess impacts of up slope water withdrawals due to french drains on building slab settlement in light of organic soils; and on slope stability. c. This parcel is not included in storm water L.I.D. No. 17, as was incorrectly stated in the checklist. d. All storm water control facilities and phasing shall be specified and approved by the Tukwila Public Works Dept. and WSDOT as applicable. D. Noise Summarize the JGL noise study. It may be reasonable to simply incorporate the text discussion. Mitigation should include all recommendations. Also as a mitigation measure, JGL will be later retained by the City to work with the architect to ensure that interior 45 dba Leq levels are achieved. Design shall be to a 40 dBa Leq level to incorporate a 5 dB engineering safety factor. JGL work shall be funded by the applicant. Consultant Note:Engineering safety factor is 3 -5 dB. A 5 dB factor reflects the City accepting the maximum 45 dB noise standard recommended by the EPA. E. Aesthetics View impacts of the two project alternatives will be displayed in an easily readable form. An 11x17 inch fold out may be required for each impact picture. Impacts will be as shown on the attached map. These are generally views at a 6 ft. height from City Hall; So. 180th St. at Southcenter Parkway; Andover Park West and Strander Blvd.; and at the southern end of 53rd Avenue South. F. Transportation a. So. 178 St. is not available as a year -round street due to the 21% grades. d. Evaluate the need for specific road improvements to mitigate immediate development impacts, the need for a no protest agreement for the formation of an R.I.D. to provide the project's fair share in resolving cumulative transportation impacts, and pedestrian improvements will be based on the following studies: Mr. William Polk June 8, 1989 Page 5 • i. Trip generation and distribution of ADT and PM peak hour traffic, and the following LOS intersection analyses: Southcenter Parkway /So. 180th St.; Military Rd. So. /So. 178th St.; Military Rd. So. /So. 188th St. and 1 -5 ramps /So. 188th St. LOS analysis shall be per the latest ITE capacity manual. ii. Vehicle and pedestrian safety analysis of So. 178th St. between the site and Southcenter Parkway. Pedestrian walking routes, school routes, and school and Metro bus accessibility are specific pedestrian safety items to evaluate. iii. Emergency access impairment for fire, police, and ambulance due to weather, 21 % grades, and difficulty to repair failed utility systems when they block access; needs to be identified. iv. Identify King County and WSDOT requirements for new 1 -5 freeway ramps at its intersection with So. 178th St. v. Identify mitigation and funding for safety and capacity impacts. This would include the vehicle, pedestrian, and emergency access; and not necessarily be limited to previously noted mitigating actions on the submitted SEPA checklist (i.e. a turning lane at the project entry). vi. A topographic survey by a licensed surveyor and plan view of the site relative to the proposed development shall be provided at a minimum 50 ft. scale. Spot elevations as shot in the field shall be located. G. Utilities a. Certification of water availability from W.D. No. 75 shall be required. Tukwila fire pressure and flow standards shall be satisfied and documented. b. A gravity sewer system is required. The sewer system capacity to satisfy existing demands is marginal. An engineering analysis of availability at the site and sewer system capacity to satisfy project demand shall be conducted. Horton Dennis (Marty Penhallgram) has recently completed an evaluation of sewer capacity in the area. c. Evaluate the need to provide for the impacts of failed sewer and water systems (i.e. by thrust blocks and double walled pipes, and regular maintenance). d. Identify specific improvements to system capacity to satisfy the immediate needs of the project, and any "no protest" L.I.D. agreements which should be executed to ensure the project pays its fair share of cumulative system improvement needs. Mr. William Polk June 8, 1989 Page 6 • • All analyses shall be directed City of Tukwila staff, with consultants approved by the City. Resumes, project examples and references shall be required of all consultants. Additional City consultation with a selected geotechnical consultant and structural engineer to aid in project review shall be paid for by the applicant. Vernon Umetsu of my staff will be available to answer your questions at 433 -1858. Specific technical questions should be resolved directly with the appropriate departments. Attachments cc: Bruce McCurdy Ron Cameron Gary Kacinski Bill Betlach Catelin Williams Rick Lawrence File Si cer —�` - -`. Beeler, Planning 'rector AT /f C HM EKT A DAM S &. MOORE A rl:•.,rr:n u)r,Ai. • i.rMrren rAtrrNi:rts1111' '500 MARKET PLACE. HI -IS ' AE k.N l •SEATTLE. 'WASHINGTON 7.; (ril.•J /Ir .1/4.1 May 10, 1989 ' The City of Tukwila 6200 Southcenter Boulevard '1 ukwila, Washington 98188 Attention: Mr. Phil Fraser Revised Proposal Review of Geotechnical;Report and Preliminary Plans Rainier Ridge for The City of Tukwila { Gentlemen: RECEEVED Mel 1 1 1989 TUKWILA PUBLIC WORKS Dames & Moore is pleased to present this revisecl proposal to review the geotechnical reports by Rittenhouse -Zeman & Associates and to review the geotechnical and hydrological aspects of the preliminary plans by Tritec Associates, Inc. W/ understand the purpose of this review is to determine what information is needed to decide that the proposed development will not have a geotechnical failure affecting safety and economics. The documents provided us for review are: 1. "Subsurface Exploration and Geotechnical Engineering Report, Proposed Rainier Ridge Apartments, South 178th Street & Interstate 5, Tukwila, Washington," for Holly Homes Company, 8222 Washington Boulevard S.W., Tacoma, Washington, by Rittenhouse - Zcinun & Associates, Inc., Bellevue, Washington, November, 1988. 4. Letter report, "Summary of Oeotechnical Design Recommendations, Rainier Ridge Apartments: Eastern Buildings, Tukwila, lashington," for Holly Homes Company, by Rittenhouse -Zeman & Associates, Inc., 21 December 1988. 3. "Supplemental Subsurface Exploration and Geotechnical Engineering Report, Proposed Rainier Ridge Apartments, South 178th Street and Interstate 5, Tukwila, Washington," for Holly Homes Company, by Rittenhouse -Zeman & Associates, Inc., February 1989. 4. Luudsuape Masterplan by Thomas Rengstorf, ASLA, no date. 5. Letter report, "Description of Foundations and First Floor Framing for Buildings A, B and C," by Robert Fossatti Associates, 3 April 1989. ;,rri(..r.r x. •rc;.n\' rii. • • DAMES& MOORE A PR%11,17. K)Nn1.1.t:1A1irl PARrNI:P.S1 The City of Tukwila May 10, 1989 Page 2 6. Site Plan /Building Elevations, 8 sheets, by William Polk Associates, no date. 7. Letter, "Rainier Ridge Apartments - SEPA Review," to Mr. L. Rick Beeler, Planning Director, City of Tukwila, from Mr. William B. Betlach, Project Manager, Tritec Associates, Inc., 3 April 1989. 8. Letter, "SR 5, MP 153.15 Vic., CS 1767, Status of Rainier Ridge Apartment Complex," to Mr. William B. Betlach, Tritec Associates, Inc., from Mr. James L. Lutz, WSDOT, 3 April 1989. 9. "Rainier Ridge Apai tuieiils, Noise Study," tip Trite; Associates Inc., Silverdale, WA, from JGL Acoustics, Inc., Bellevue, WA, 3 April 1989. 18. !Fcrmit Application uocuments, Lay 01 t tikwala. Speeifieully, our scope includes the following: 1. Review the submitted documents for comr}leteness and report on itemized deficiencies. 2. Evaluate the Rittenhouse -Zeman & Assoc ?ates (RZA) site investigations to determine if the investigations included enough explOratory borings and excavation pits. 3. Review and evaluate the RZA geotechdical and groundwater analysis and design recommendations and conclusions that relate to: o Site Stability o Foundations " Slopes o Retaining walls " Rockeries o Site drainage, permanent run -off control, upstream and downstream run -off effects and /or considerations 4. Evaluate acceptability of construction recQrttuiendations. o Temporary construction period run -off' control o Construction limitations due to weather MkDAMES g 1tl OORE Al. L.ur.irihr.., PAR rT- irr.si�ii The City Of Tukwila May 10, 1989 Page 3 5. Evaluate suggested /recommended monitoring programs for construction and for design life of project. 6. Evaluate recommended maintenance agreements, particularly for drainage facilities. Ala), uny suggested drainage casements and agreements. 7. Provide a written report and recommendations for approval /disapproval of permit based on the geotechnical and hydrological considerations. No independent analyses of existing data will be performed and we will not acquire any new site- specific subsurface data. We will complete our review within three weeks after receiving authorization. We will, in submitting our report, identify areas where 2ldd;libna1 Ai. of million is necessary iv complete the review. We will eblidUCt aUP illVegtigalib1S in accordance, with our standard Schedule or Charges and billing rates shown on the enclosed Attachments A through C. For the scope outlined above, we estimate our fee will be between $6,000 to $7,500. The cost breakdown for our services is as follows: Project Engineer/ Principal Support Keimbursible & Item Man Hours Time Hours Equipment Total 1 12 50 1,100 2 -4 25 5 100 2,600 5 6 -- 500 6 8 2 50 800 7 12 10 200 1,800 Pi 0.4401 Management/ Billing, etc, 5 3 JIM Estimated Total '1�(1Q DA The City of Tukwila May 10, 1989 Page 4 S6,1. MOORE A TR `Fr -;};I :A'PJ LimITEDPARTNERSHIV It has been a pleasure preparing this proposal for you and we look forward to working with you on this project. If you have any questions, please call us, YUuni vuiy truly, DIAMES.& MOORE !-I rb ns L. Chabra, P.E, Pt'incipal Engineer /Assuuiate Ht.C•:kh I cAkuh \suits \prup9 \tukwlla.lra air . :v�:;i \ ' °.�; i I'II;= ',%',..,-2.':.-. M \ilk n r i ^(o X''' R -A \ VIE ) IM PACT �.o A0141-Ys1S �.� M P ew\ ZONi:NG s 0 Q"";' vices T AND 'Dr2�cT�on< 14ATM ST R-I -120 R -A \ R -1 -72 R -1 -120 P0: C-2! RMi R -I -120 C -2 P-0° R-4\ w.�E, (I • 0 P-I -72 R3 TUKWILA .raacMlKw M-1 AY 407 4 R -I -12.0 `P- I- 120".1 R -1-120 C -P R -I -120 R -1 -7.2 R -1 -120 R -A AGRICULTURAL R -I -120 SINGLE FAMILY RESIDENTIAL R-1 -96 SINGLE FAMLY RESIDENTIAL R -1 -72 SNGLE FAMLY RESIDENTIAL R -2 TWO FAMILY RESIDENTIAL rer R-3 THREE AND FOUR FAMLY RESDENTIAL R-4 LOW APARTMENTS RMH MULTIPLE MULTIPLE RESDENCE HIGH DENSITY C-M NECK PA, P-0 PROFESSIONAL AND OFFICE C -I NEIGHBORHOOD PETAL C-2 REGIONAL RETAIL F-1 PLANNED BUSNESS CENTER C -M INDUSTRIAL PARK M -I I LIGHT INDUSTRY M -2 FEW( INDUSTRY * RESTRICTED ZONING -1-120 TRAM. (Al R-A R -A M -2 C -M ::I7'1ETRO • Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104 -1598 May 1, 1989 Rick Beeler, Planning Director City of Tukwila 6200 Southcenter Blvd. Tukwila, Washington 98188 Determination of Significance File Name: Southcenter Gateway Associates Dear Mr. Beeler: NTT N �! �� -� L'!��' 1\11 AY 2 1989 The Draft EIS on this proposed apartment development should provide information regarding planned wastewater disposal system(s), projected peak and average wastewater flows, and impacts to downstream wastewater facilities. Metro staff advises that a Transportation Management Plan (TMP) be for this proposed development and evaluated in the Draft EIS. The TMP should include the following component: Public transportation information display; - Annual information dissemination; - Free 1 -month bus pass (or vanpool fare) to new tenants upon request; - Appointment of a transportation coordinator; - Secure bicycle storage; and Monitoring of travel behavior. The developer should coordinate the TMP with Carol Thompson, Metro Market Development Planner, at 684 -1610. Sincerely, Gregory M. Bush, Manager Environmental Planning Division GMB:jmg4624 Law Offices HANSON, BAKER, LUDLOW AND DRUMHELLER, P.S. John M. Baker II Betty L. Drumheller Janet Gray John E. Hanson John T. Ludlow Paul D. Rytting Jerry A. Stimmel Linda M. Youngs William E. Zwink (1980) Mr. Rick Beeler CITY OF TUKWILA PLANNING DEPARTMENT 6200 Southcenter Blvd. Tukwila, Washington 98188 May 1, 1989 300 Surrey Building 10777 Main Street Bellevue, Washington 98004 (206) 454 -3374 FAX (206) 454' -0087 Re: Comments on Scope of EIS, File No. EPIC 33 -88 Proponent: Southcenter Gateway Associates Dear Mr. Beeler: MAY 2 1989 M We represent Ray Flink, a property owner to the south of the Southcenter Gateway Associates proposed apartment project. Mr. Flink currently has his property before the City of Tukwila for a re -zone for apartment uses. The City of Tukwila has expressed concerns regarding the safety and grade of South 178th Street. We request that the environmental impact statement for the Southcenter Gateway Associates project include analysis of the potential for realignment of South 178th Street through the McCurdy property. We believe the roadway could be placed on a bench through unbuildable area, which would result a substantially reduced grade to South 178th Street. Participation in improvements to South 178th Street was a condition of the McCurdy re -zone approval Ordinance No. 1124, enacted August 6, 1979. Such an analysis is necessary to mitigate the increased traffic which the project will place on South 178th Street. If you have any questions, please feel free to contact me. Very truly yours, BAKER, HELLER DLOW AND • BLD /lr cc: Ray Flink 4660 -08Y Betty . Drumheller CHRISTINE O. GREGOIRE Director STATE OF WASHINGTON DEPARTMENT OF ECOLOGY i 777, Mail Stop PV -11 • Olympia, Washington 98504 -8711 • (206) 45 %000 April 27, 1989 MAY 11989 Mr. Rick Beeler City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Dear Mr. Beeler: Thank you for the opportunity to comment during the scoping process for the Rainier Ridge Apartments proposed by Southcenter Gateway Associates. Construction activities, particularly those on steep slopes, have a direct potential to cause increased turbidity in sur- face waters. Potential impacts and possible mitigation mea- sures should be discussed in the draft environmental impact statement. A restoration bond may be needed to ensure the implementation of a temporary erosion and sedimentation control plan. This plan should be submitted along with the permanent storm drainage plans for engineering review. If you have any questions, please call Ms. Rachel Friedman - Thomas of the Northwest Regional Office at (206) 867 -7128. BJR: cc: Rachel Friedman - Thomas Sincerely, Barbara J. Ritchie Environmental Review Section 3 RITTENHOUSE•YIAN & ASSOCIATES, INC. Geotechnical & Environmental Consultants 1400 140th Avenue N.E. Bellevue, Washington 98005 -4594 (206) 746- 8020 /FAX (206) 746 -6364 23 March 1989 W- 5873 -1 Tritec Associates P.O. Box 1914 Tacoma, Washington 98401 Attention: Mr. Bill Betlach Subject: Geotechnical Report Submittal Proposed Rainier Ridge Apartments S 178th Street and Interstate -5 Tukwila, Washington Gentlemen: We are pleased to present herein all geotechnical reports prepared by our firm through 23 March 1989 for the referenced project. This submittal includes: Subsurface Exploration and Geotechnical Engineering Report dated 15 November 1988; Summary of Geotechnical Design Recommendations, Eastern Buildings, dated 21 December 1988; Supplemental Subsurface Exploration and Geotechnical Engineering Report, dated 20 March 1989; and Addendum to Geotechnical Report, dated 22 March 1989. We appreciate this opportunity to be of service to you. Our firm is available to provide additional consultation regarding specific design details if necessary, and to provide construction observation services. Please feel free to call if you have any questions or need additional information. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. tihn E. Zipper, P.'E. Associate • • 20 March 1989 W- 5873 -1 Holly Homes Company P.O. Box 99953 Tacoma, Washington 98499 Attention: Mr. Jerry Flansburg Subject: Supplemental Subsurface Exploration and Geotechnical Engineering Report Proposed Rainier Ridge Apartments South 178th Street and Interstate 5 Tukwila, Washington Gentlemen: We are pleased to present herein a copy of the above referenced report. This report represents the results of our supplemental subsurface exploration and geotechnical engineering study relative to the foundation and construction considerations for the eastern portion of the proposed project. Authorization to proceed with this study was granted verbally by Ms Cynthia Lohman of William Polk Associates, 13 December 1988. This study has been completed in general accordance with our proposal dated 13 December 1988. A summary of geotechnical recommendations for the project was sent on 21 December 1988. This report supplements our geotechnical report for the remainder of the project dated 15 November 1988. We appreciate this opportunity to be of service to you and would be pleased to discuss the contents of this report or other aspects of the project with you at your convenience. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. Henry W. Brenniman, Engineering Geologist cc: Cynthia Lohman /William Polk Associates Bill Betlack • Supplemental Subsurface Exploration and Geotechnical Engineering Report Proposed Rainier Ridge Apartments South 178th Street and Interstate 5 Tukwila, Washington Prepared For Holly Homes Company P.O. Box 99953 Tacoma, Washington 98499 Prepared By Rittenhouse -Zeman & Associates, Inc. 1400 - 140th Avenue N.E. Bellevue, Washington 98005 February 1989 W- 5873 -1 1.0 SUMMARY TABLE OF CONTENTS W- 5783 -1 2.0 PROJECT DESCRIPTION Page 1 2 3.0 SITE CONDITIONS 3 3.1 Surface Conditions 3 3.2 Subsurface Conditions 4 4.0 CONCLUSIONS AND RECOMMENDATIONS 4 4.1 Site Preparation 5 4.2 Structural Fill 6 4.3 Foundation Recommendations 6 4.4 Slab -On -Grade •g 4.5 Wall Backf i l l g 4.6 Cut - And -Fill Slopes 10 4.7 Slope Stability 11 4.8 Drainage Considerations 12 5.0 CLOSURE 12 Figure 1 - Site and Exploration Plan Appendix A - Subsurface Exploration Procedures and Logs SUPPLEMENTAL SUBSURFACE EXPLORATION AND GEOTECHNICAL ENGINEERING REPORT PROPOSED RAINIER RIDGE APARTMENTS SOUTH 178TH STREET AND INTERSTATE 5 TUKWILA, WASHINGTON 1.0 SUMMARY The proposed project on the eastern portion of the site below the break -in -slope is considered feasible based on the subsurface conditions encountered on the site. A brief summary of the project geotechnical considerations is presented below. • A total of five borings were advanced with hollow -stem augers across the eastern portion of the parcel. The borings were accomplished to depths of up to 45 feet below the existing ground surface. The borings above the break -in -slope encountered up to 5 -1/2 feet of loose to medium dense, gravelly, silty sands overlying very dense, gravelly, silty sands, hard silts and silty fine sands. The borings below the break -in -slope encountered dense to very dense, gravelly, silty sands and silty fine sands with discontinuous layers of hard silt. • We observed no evidence of deep- seated slope instability during our site visit. The soils comprising the slope consist of very dense, glacially overridden soils. Due to their high strength, these soils are capable of supporting the structures with a high factor of safety relative to slope stability. In our opinion, there is minimal risk of slope instability affecting foundations on -site, provided proper design and construction procedures as described in this report are followed. ▪ Ground water was encountered in four of the five borings and ground water seepage was observed in sands below the glacial till soils. Excavations on -site should be expected to encounter ground water seepage. It will be necessary to slope excavations back, blanket seepage areas with quarry spalls or rip -rap, and drain seepage away from the foundation and downhill slope areas where encountered. Areas of excessive seepage may require well -point dewatering. • We recommend the use of augercast pile foundations for support of buildings on the site slopes. We recommend a minimum auger pile depth of 15 feet below pile cap and that the top of pile be offset horizontally at least 5 feet from the adjacent face of slope. For a 12 -inch diameter augercast pile, a design vertical compressive capacity of 20 tons is recommended. Lateral pile capacities are limited by the proximity of the site slope. A range of capacities is given in the body of the report. Holly Homes Company/Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 2 O The proposed retaining wall west of the proposed buildings can be supported on a shallow continuous foundation bearing on undisturbed very dense soils. We recommend a horizontal offset from the adjacent slope face of 15 feet. An allowable soil bearing pressure of 6000 pounds per square foot is recommended with this configuration. A foundation base friction coefficient of 0.5 and a passive pressure equivalent fluid weight of 350 pounds per cubic foot can be used for design. O Due to the site slopes and proposed building configuration, it will be necessary to provide erosion protection in areas downslope of foundations and any areas exhibiting ground water seepage. In order to minimize risk from erosion and surface soil creep, we recommend that no fill be placed on existing site slopes, use of jute or excelsior matting in areas to be planted and diversion of all surface water through tight -lines from site slopes. This summary is presented for introductory purposes only and should be used in conjunction with the full text of this report. The project description, site conditions and detailed geotechnical design recommendations are presented in the text of this report. Exploration procedures and logs are presented in Appendix A. 2.0 PROJECT DESCRIPTION The proposed project encompasses an area of approximately 6.6 acres, located at the northeast corner of South 178th Street overpass on Interstate 5 in Tukwila, Washington. We understand according to the revised plans provided to us, that the property will- be developed for five multi -unit, three -story wood - framed apartment buildings with daylight- basements, adjacent clubhouse and swimming pool. Three of the apartment buildings are being proposed below the break -in- slope. Proposed building and access road locations as well as the approximate locations of the explorations accomplished for this study are shown on the Site and Exploration Plan, Figure 1. This report supplements our geotechnical report for the western portion of the parcel, dated 15 November 1988. The purpose of this supplemental evaluation is to establish general surface and subsurface conditions for the three proposed apartment buildings on the eastern side of the parcel below the break -in- slope. The scope of work consisted of field explorations, visual assessment of site • Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 3 conditions, geotechnical engineering analyses and report preparation. In the event that any changes in the nature, design, or location of the structures is planned, the conclusions and recommendations contained in this report should be reviewed and modified if necessary to reflect the changes. This report has been prepared for the exclusive use of Holly Homes Company and their agents, for specific application to this project in accordance with generally accepted geotechnical engineering practices. 3.0 SITE CONDITIONS The site conditions were evaluated on 16, 19 and 20 December 1988. The surface and subsurface conditions are described below, while the exploration procedures and interpreted logs of explorations are presented in Appendix A. The proposed site development and approximate locations of explorations are indicated on the Site and Exploration Plan, Figure 1. 3.1 Surface Conditions As noted in our initial Subsurface Exploration and Geotechnical Engineering Report dated November 1988, the site is comprised of two areas, the western, gently sloping, upper plateau and the eastern steep slope. These two areas are bisected by a break -in -slope trending southeast to northwest. Ground surface elevations in the area of our investigation range from 235 feet at the break -in -slope to' an approximate elevation of 175 feet at the eastern edge of the parcel. The ground surface slopes down at approximately a 2H:1V (Horizontal:Vertical) slope towards Southcenter Parkway. Vegetation on the steep slope was relatively undisturbed and consisted of maple, alder and fir trees with an understory of blackberry, ferns, salal, and brush. There is a large area of standing water at the toe of slope in the southeast central portion of the site. There appears to be a slight depression in this area where run -off from rainfall and spring seepage along the slope is collecting. Areas of seepage were observed below the glacial till soils approximately 50 feet north of boring B -4 and east of boring B -5. In our opinion, the spring seepage could be occurring from water perched on hard silt interbeds in the advance sands where contacts are exposed at the surface. • • Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 4 3.2 Subsurface Conditions In general, our exploration showed variation in stratification near the surface, however, at depth, all explorations encountered dense to very dense glacially overconsolidated, silty fine sands with the exception of boring B -2 which penetrated this strata and bottomed in a very dense glacial till soil. The glacial till and all soils stratigraphically below, have been overridden in the geologic past by the glacial ice mass, compressing the soil with the weight of thousands of feet of glacial ice. As a result, the soils exhibit both high strength and low compressibility characteristics. The borings at the top of slope (B -1 and B -2) encountered a surficial loose to medium dense, wet, gravelly silty sand to a depth of 4 to 5 feet. Below this surficial weathered deposit, and from the ground surface in borings B -3, B -4, and B-5, all soils encountered consist of dense to very dense, glacially consolidated soils. A minor amount of compressed organic material was encountered in boring B-1 at 38 feet depth. Due to the glaciation, this material does not represent a significant variation of soil strength or compressibility. Ground water levels varied across the site. Boring B -3 showed a perched water table in the dense, silty fine sand occurring at 8 feet in depth above a hard silt interbed. Boring B-1 encountered groundwater at 32 feet in depth. This also appears to be,perched on a hard silt interbed which occurs at 38 feet in depth. Borings B -2 and B -5 encountered ground water in the very dense, silty sand at levels of 17 and 11 feet, respectively. Boring B -4 did not penetrate any perched water or ground water. During our visual observation of the hill slope, we observed water seeping out of the hillside north of boring B -4 and east of boring B -5. It should be noted that subsurface seepage volumes and ground water may fluctuate due to variations in site utilization, season, rainfall and other factors. 4.0 CONCLUSIONS AND RECOMMENDATIONS Development plans call for the construction of three, three -story plus daylight - basement, wood - frame, multi - family apartment buildings below the break -in -slope • • Holly Homes Company /Rainier Ridge Apartments W- 5873 -1 20 March 1989 Page 5 for this site. In our opinion, the development as proposed is feasible from a geotechnical standpoint. Based on the soil conditions encountered in the borings, we recommend the use of pile foundations for support of structures on the slopes. 4.1 Site Preparation The conceptual design drawings provided Rittenhouse -Zeman & Associates, Inc. (RZA) are preliminary in nature. Consequently, we have provided general site preparation recommendations considering the subsurface conditions encountered in our explorations and our understanding of the proposed development. Initial site preparation will involve clearing and stripping of construction areas. Areas of the proposed buildings, floor slab, sidewalks and areas to receive "structural fill ", should be stripped of all brush, vegetation, topsoil and other deleterious materials. Areas of deeper organics if any, encountered in the areas to be developed, should be removed and backfilled with "structural fill ". Disturbance of the soils and vegetation on the steep slopes to the east of the proposed buildings should be minimized during construction. The suitability of the native soils for floor slab and wall foundation support should be evaluated prior to "structural fill" placement. Where soils exposed by strippi� possess a minimum density of at least 90 percent of the modified Proctor maximum dry density, (as determined by the ASTM:D 1557 test procedure) no further site preparation would be required. Should portions of the site soils not meet or exceed the above minimum standard, we recommend those foundation and slab subgrade areas be prerolled and compacted with a roller or other suitable heavy equipment to a firm and non - yielding condition in order to achieve the minimum compaction level. The near - surface site soils are silty and consequently, highly moisture - sensitive. The silty soils are highly prone to disturbance when in a wet site condition. To reduce site disturbance, the contractor should minimize traffic above prepared subgrade areas and direct site surface and ground water away from the work areas. A network of drainage ditches and sumps may be necessary to collect and discharge Holly Homes Company/Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 6 groundwater seepage from excavations. Areas of excessive seepage may require wellpoints to adequately dewater excavations. In very wet conditions, the use of a working surface of quarry spalls or sand and gravel may be required to protect the subgrade, especially from vehicular traffic. 4.2 Structural Fill All fill placed in the building areas as well as under floor slabs, sidewalks and for the backfill of walls, utility trenches and footing, should be placed in accordance with the recommendations for "structural fill" outlined in our initial Subsurface Exploration and Geotechnical Engineering Report prepared for the proposed development, dated 15 November 1988. 4.3 Foundation Recommendations Support of the proposed buildings is considered feasible based on the subsurface conditions encountered on the site. We recommend the use of pile foundations for support of structures on the site slopes. It appears that cast -in -place concrete augercast piles are a suitable pile type based on the soil conditions encountered in the borings. A possible alternative would be a cast -in -place concrete pile, cast in an open drilled holed. An augercast pile is formed by drilling to a pre- determined depth with a hollow -stem auger. Cement grout is then pumped down the stem of the auger under high pressure as the auger is withdrawn. The final result is a cast -in -place concrete pile. Reinforcing can be installed in the unset concrete column to provide lateral and tension capabilities, if required. We recommend that depth of the augercast piles be a minimum of 15 feet below the pile cap and that the top of pile be offset horizontally at least 5 feet from the adjacent face of slope. A vertical compressive capacity of 20 tons is recommended for 12 -inch diameter augercast piles bearing in the very dense glacially overconsolidated soils. Foundation settlements are anticipated to be less than about 1/2 inch. We recommend a minimum spacing for all piles of three -pile diameters center -to- center. Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 7 Lateral pile capacities are limited by the proximity of the site slopes. Lateral pile capacities will depend on the top of pile offset from the slope face, the direction of loading, and the spacing of piles in groups. Table I below presents recommended lateral pile capacities for design. This table presents the capacity of the soil /pile interaction. Suitable reinforcing for the pile section (i.e., moment cage) will be required to fully develop these soil capacities. TABLE I W- 5873 -1 • LATERAL PILE CAPACITIES 12 -inch diameter Augercast Ultimate Loading Condition Lateral Resistance (pounds) Single Pile: Per Pile: E -W loading 5,000 5-ft. offset to slope face E -W loading 7,500 10 -ft. offset to slope face E -W loading 15 -ft. offset to slope face 10,000 N -S loading 12,000 Two -Pile Group: E -W loading 3 -ft. spacing 5 -ft. offset to slope face E -W loading 8-ft. spacing 5 -ft. offset to slope face N -S loading 3 -ft. spacing N -S loading 8 -ft. spacing Three -Plus Pile Group: 3-ft. spacing Per Group: 6,500 10,000 18,000 24,000 Per Group: Two -pile group values, plus one -half of single pile resistance 8 -ft. spacing Sum of single pile resistance • 1 Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 8 The proposed retaining wall along the west side of the buildings can be supported on a shallow continuous foundation bearing on undisturbed very dense soils. We recommend the eastern edge of the footing have a horizontal offset of at least 15 feet from the adjacent slope face. An allowable soil bearing pressure of 6000 pounds per square foot can be used for the design with this configuration. If distrubed or soft materials are left within the footing area prior to concrete placement, future settlements may be greatly increased. For that reason, the condition of the footing subgrade should be evaluated by a representative of RZA ,Inc. prior to concrete placement to confirm the condition of the bearing soils are consistent with those assumed during design. Obstructions to drilling may be present at random depths and locations in the fill -soils on the site. It may be necessary to revise pile locations and associated pile cap designs during construction, if obstructions are encountered. We recommend that the construction budget include a contingency for such redesigsn, as well as for pile installation costs associated with extra drilling. Based on the borings advanced for this study, the recommended depths of Augercast piles at specific boring locations have been estimated. However, the elevation and nature of the bearing layer between explorations is not known and can only be interpolated. For this reason, we strongly recommend that the installation of all piles be observed by Rittenhouse -Zeman & Associates, Inc. Our representative would observe the contractor's operation, collect and interpret installation data and determine the required pile penetration depth. It may be necessary to confirm the nature of the bearing material by withdrawing the auger at selected pile locations to examine the materials retained on the auger cutting teetch. In order to provide an evaluation of Augercast pile installation, as a minimum, we recommended the contractor be required to provide a pressure gauge in the grout line between the pump and the auger, and a means of determining the quantity of grout used per pile, such as a calibrated stroke - counter on the grout pump. Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 9 4.4 Slab -On -Grade The slab -on -grade floor subgrade should be prepared in accordance with previous site preparation recommendations. Slab -on -grade floors should be founded on prerolled native ground or structural fill placed and compacted as per our recommendations outlined previously. We recommend that the floor slab be underlain by a minimum of 6 -inch thickness of clean sandy gravel, crushed rock, or pea gravel to serve as capillary break and working surface. Impervious moisture barrier should also be placed beneath the slab. To protect the membrane from punctures associated with reinforcement placement, the Portland Cement Association recommends at least 2 inches of sand between the vapor barrier and concrete slab. Ground water was encountered in four of the five borings and groundwater seepage was observed near areas of the proposed buildings. It may be necessary to provide subsurface drains below floor slabs or in crawl spaces, for buildings which are located below existing grades. We recommend that the final recommendation regarding locations and depths of subfloor drains be made by RZA during construction, on a building- specific basis. The final recommendations would be based on the ground water conditions encountered at each building site. 4.5 Wall Backfill Retaining walls constructed that allow some deflection during backfill placement may be designed to resist a lateral force equivalent to a fluid weighing 30 pounds per cubic foot (pcf) for a level ground surface. Walls that are structurally restrained from lateral movement at the top may be designed with an equivalent fluid unit weight of 50 pcf. A minimum width of 2 feet of clean, granular backfill should extend from the base of the wall up to the ground surface which can communicate freely with the wall footing drain. This drainage layer is intended to preclude the buildup of hydrostatic forces. Clean, granular backfill should contain less than 5 percent passing a No. 200 sieve, by weight, based on the portion of the soil passing a No. 4 sieve. A value for the allowable passive earth pressure of 350 pounds per cubic foot may be assumed for each foot of penetration below the ground surface, neglecting the • • Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 10 first foot. Passive resistance should be neglected within 10 feet of slopes, in the downslope direction. An allowable wall base friction value of 0.50 is recommended. These are allowable values, and include a factor of safety of at least 1.5. All backfill placed behind walls should be placed as per our structural fill recommendations of this report. The previous recommended earth pressures presented as equivalent fluid unit weights are based on the assumption of uniform level granular backfill and no buildup of hydrostatic pressure behind the wall. To minimize lateral earth pressures and prevent the buildup of hydrostatic pressures, the wall backfill should consist of free - draining granular material with drainage provisions as discussed subsequently in this report. We recommend that silty on- site soils not be used as backfill directly against walls. Surcharges due to sloping ground, adjacent footings, vehicles, construction equipment, and other loads, must be added to these values. We recommend a 75 percent increase in the above wall pressures for a 2H:1V backslope. The above equivalent fluid unit weight assumes the backfill is compacted to approximately 90 percent of the modified Proctor laboratory maximum dry density (ASTM:D 1557). Additional compaction adjacent to the wall will increase the lateral pressures, while a lesser degree of compaction may permit excessive post- construction settlement. It should be noted that limitations placed on compaction may allow some minor settlement of the wall backfill with time. Typically, this is not a problem, except for settlement- sensitive surfaces or structures which are founded in the backfill, or where utilities penetrate backfilled walls. 4.6 Cut - And -Fill Slopes We recommend that permanent cut and fill slopes on the property be designed with a maximum slope of 2H:1V. The surface of fill slopes should be compacted to the same 90 percent density as the body of the fill. This may be accomplished by overbuilding the embankment and cutting back to its compacted core. The cut -away material should, however, be removed from the fill slope. Alternatively, the • • Holly Homes Company /Rainier Ridge Apartments 20 March 1989 W- 5873 -1 Page 11 surface of the fill slope may be compacted as it is built. Fill placed on existing slopes steeper than 5H:1V should be keyed and benched into the existing firm, stable soils. All slopes should be protected from runoff by berms, wales, and if necessary, an impervious cover. We recommend hydro- seeding exposed cut or fill slopes to reduce the potential for erosion. If erosion occurs on any slope, the use of a layer of quarry spalls or sandy gravel may be required across the surface of the slope to mitigate additional erosion. Due to the site slopes and proposed building configuration, it will be necessary to provide erosion protection in areas downslope of the foundations, and in areas exhibiting ground water seepage. Areas which will be planted should be faced with jute or excelsior matting and planted with appropriate deep- rooted, self - propagating, vegetative cover. Areas exhibiting ground water seepage, and areas extending at least 30 feet downslope of foundations, should be surfaced with at least a 1 foot -thick layer of quarry spalls. Maintenance of the erosion protection will be required throughout the life of the structure. 4.7 Slope Stability We observed no evidence of deep- seated slope instability during our field exploration program. We did, however, observe some evidence of minor surficial soil movement near the toe of slope. This surficial soil movement consisted of a minor slump located in the southeast - central area of the site east of the south proposed building. Based on the findings of our explorations, which encountered very dense, glacially consolidated soils at depth, the overall stability of the site slopes appears to have a high factor of safety. We anticipate that minor surficial soil movement in the future could be limited to surficial sloughing or slope creep affecting small amounts of soil from the steeper slope faces. Provided the recommendations contained in this report are incorporated into the development, the risk of slope instability affecting the foundations of structures on this site is minimal, in our opinion. Holly Homes Company /Rainier Ridge Apartments W- 5873 -1 20 March 1989 Page 12 Disturbance of soils and vegetation on the steep slopes to the east of the proposed buildings should be minimized during construction. Any disturbance or modifications to the surrounding slope should be reviewed by the project geotechnical engineer. No stripped material or any other soil should be pushed over the steep slopes. Any loosened material spilled over the slopes would be increasingly susceptible to progressive failure. No water should be discharged onto the slope face. 4.8 Drainage Considerations The surficial soils are susceptible to erosion, and the site soils are silty and highly susceptible to disturbance when wet. Prior to construction, the site surface or ground water should be routed away from the construction and building areas as much as possible. It is recommended that the buildings be provided with a perimeter footing drain system to collect available water. Footing drains should consist of at least a 4 -inch diameter perforated pipe with an envelope of pea gravel or washed rock. A tight -line drain network should be led away from the building via gravity to a storm sewer or other suitable discharge. Site grades should be planned to provide a positive gradient away from the building. Roof and surface runoff should not be permitted to discharge into the footing drain system. Instead, a separate tight -line drain network should be installed to direct rainfall away from the completed building and site slopes. 5.0 CLOSURE The conclusions and recommendations presented in this report are based on the explorations accomplished for this study. The number, location and depth of the borings were completed within the site constraints so as to yield the information to formulate our recommendations. The proposed development appears to be feasible with adequate care addressed to site stripping, drainage and slope configuration. The integrity of the foundation depends on proper site preparation and construction procedures. We would be available to provide geotechnical engineering services during earthwork and foundation construction phases of the project. If variations in the subsurface conditions are observed at that time, we would be available to provide additional geotechnical recommendations to minimize delays as the project develops. Holly Homes Company /Rainier Ridge Apartments W- 5873 -1 20 March 1989 Page 13 It has been a pleasure to provide you with this information. If you have any questions, please do not hesitate to call at your convenience. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. ti) e/f,e4vywyna-- Henry W. Brenniman, Engineering Geologist John E. Zipper, .E., Associate PROPOSED PARKING (TYPICAL) PROPOSED APARTMENT BUILDING (TYPICAL) EXPLANATION B- B -5 INDICATES BORING NUMBER AND ® APPROXIMATE LOCATION DRAWING BASED ON FAX BY WILLIAM POLK ASSOCIATES 21 DEC 1988. 0 60 120 APPROXIMATE SCALE IN FEET RAINIER RIDGE APARTMENTS TUKWILA, WASHINGTON SITE & EXPLORATION PLAN FIGURE 1 W.O. W- 5873 -1 BY JZ DATE DEC 1988 SCALE NOTED RZA RITTENHOUSE -ZEMAN & ASSOCIATES, INC. Geotechnical & Hydrogeological Consultants ;for � 1400 140th Avenue N. E. Bellevue, Washington 9500 • • APPENDIX A SUBSURFACE EXPLORATION PROCEDURES AND LOGS APPENDIX A W- 5873 -1 Field Exploration The field exploration program conducted for this study consisted of advancing a series of five borings. The approximate boring locations are illustrated on the Site and Exploration Plan, Figure 1. The boring locations were obtained in the field by taping from existing site features. Elevations were interpolated from contours on a topographic lan. Locations and elevations should be considered accurate only to the degree implied by the method used. Hollow Stem Auger Borings The borings were drilled on 16, 18 and 19 December 1988 by a local exploration drilling company under subcontract to our firm. The two borings above the break - in -slope consisted of advancing a 4 -inch inside diameter, hollow -stem auger with a truck- mounted drill rig. The three borings below the break -in -slope were advanced with a hand - portable 2 -1/2 -inch inside diameter, hollow -stem power auger. The borings were accomplished to depths of up to 43 feet below existing ground surface. During the drilling process, samples were obtained at generally 5 foot depth intervals. The borings were continuously observed and logged by an engineering geologist from our firm. Disturbed samples were obtained by using the Standard Penetration Test Procedure as described in ASTM:D 1586. This test and sampling method consists of driving a standard 2 -inch outside diameter split barrel sampler a distance of 18- inches into the soil with a 140 pound hammer free falling a distance of 30 inches. The number of blows for each 6 inch interval is recorded. The number of blows required to drive the sampler the final 12 inches is considered the Standard Penetration Resistance ("N ") or blow count. The blow count is presented graphically on the boring logs in this appendix. If a total of 50 blows is recorded within one 6 inch Continued • • Appendix A (continuation) Page 2, W- 5873 -1 interval, the blow count is recorded as 50 blows for the number of inches of penetration. The resistance, or "N" value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils. The soil samples obtained from the split - barrel sampler were classified in the field and representative portions placed in water -tight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing. Samples are generally saved for a period of 30 days unless special arrangements are made. The boring logs presented in this appendix are based on the drilling action, inspection of the samples secured, laboratory results and field logs. The various types of soils are indicated as well as the depths where the soils or characteristics of the soils changed. It should be noted that these changes may have been gradual, and if the changes occurred between sample intervals, they were interpreted. The ground water conditions observed during the exploration program are indicated on the boring logs. These subsurface water conditions were evaluated by observing the moisture condition of the samples, or the free water on the sampling rounds. The ground water level is indicated on the boring logs were appropriate by the water symbol. RITTENHOUISE- ZE11�IA , ASSOC., INC. " �! Gentccln►icnl / ll�rlrogco icnl Consultants SOIL DESCRIPTION Ground Surface Elevation Aooroximatel Feet BORING NUMB PROJECT NAME B -1 (1 of 2) W.O. W- 5873 -1 Rainier Ridge w w 1- a. w z J a 2 N zzft 0 O a v STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 3 _ Loose, to medium dense, wet, mottled gray, gravelly, silty SAND _0 _ .., c� O au 5 S. IL_ -5 _ -10 I Very dense, moist to wet, gray, gravelly, silty SAND - - illiog = _ I - 56 15 II — — Hard, moist to wet, gray, clayey SILT with some fine sand and gravel - : _ -20 -25 I I -5-6/3" 5D/ — " Very dense, wet, gray, silty fine SAND " - _ _ �-35 Compressed organics at 3S feet in SILT - interbeds 1 1111 50i"— -30 40 fATD 92 — — — — S 2' OD SPLIT SPOON SAMPLE • 3' OD SHELBY SAMPLE O 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED GROUND WATER r' u ..c.AL DATE WATER LEVEL S? AT TIME OF DRILLING AI° '`SSERVATION [ y�WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC 1 • -- LICL'ID LIMIT �--- NATURAL '.PATER CONTENT PLASTIC LIMIT Ai ilk RITTENIIOUSE -ZEM & ASSOC., INC. BORING NUM a -1 (2 of 2) W.0. w- 527: -1 1a! Geotechnical / ll�rlrn;cn �icn! Consultants PROJECT NA7Rainier Ridge SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Very dense, wet, gray, silty fine SAI10 Total depth 43 feet 16 December 1988 w w u. p_ w 40 — 45 _ 50 LAB TESTS SAMPLING z O c STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 0 10 20 30 40 50 50/3" SAMPLING GROUND WATER i LABORATORY TESTS 1 00 SPLIT SPOON SAMPLE , .. SEAL • % WATER CONTENT Ir 3' 00 SHELBY SAMPLE I DATE N 2.5' 10 RING SAMPLE WATER LEVEL C' NP NON PLASTIC _ B SULK SAMPLE AT TIME OF DRILLING Al': - OBSERVATION •_ •LICUID LIMIT WELL TIF * S NATURAL WATER SAMPLE MPLE NOT RECOVERED / CONTENT PLASTIC �LI ?.11T "— R. RITTENHOUSE -ZEN & ASSOC., INC. Gcntechnicn! / I!ydro eological Consultants SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Loose to medium dense, wet, brown, gravelly, silty SAND Very dense, wet, tan, silty sandy GRAVEL with cobbles -5 -10 Very dense, wet, gray, silty fine SAND -15 BORING NU• B -2 PROJECT NAME Rainier Ridge 0 w 0 ►- a CC 3 Q. ATD Very dense, moist, tan, gravelly, silty SAND -20 -25 -30 -35 Total depth 33 feet 16 December 19SS SAMPLING = 2' OD SPLIT SFCCN SAMPLE IC 3' 00 SHELBY SAMPLE 19 a5' ID RING SAMPLE 8 13ULI< SAMPLE * SAMPLE NOT RECOVERED 40 GROUND WATER ` SEAL w.o. W_5873 -1 STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 10 20 30 40 50 DATE WATER LEVEL ,7_ AT TIME OF DRILLING A , OBSERVATION WELL TIP LABORATORY TESTS • WATER CONTENT NP NON PLASTIC '------- � -- LICUID LIt.IIT 1_ NATURAL WATER CONTENT PLASTIC LIMIT RITTENHOUSE -ZEM & ASSOC., INC. Ceotecluricnl / Ily drogeciTii,gicnl Consultants BORING NUM PROJECT NAME SOIL DESCRIPTION Ground Surface Elevation Approximately Feet _ Dense, moist to wet, brown, silty fine SAND Hard, wet, brown sandy SILT interbed at 8 feet Very dense, moist, gray, silty fine SAND Total depth 23 feet - 19 December 1988 SAMPLING _ 2 00 SPLIT SPOON SAMPLE y 3. OD SHELBY SAMPLE 2510 RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOv'ER=__ 1- w w u. 1- a w 0 -5 10 -15 —20 —25 —30 —35 40 LAB TESTS SAMPLING I I L r ATD 21 W.O. W- 5873_1 Rainier Ridge STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 inch drop) 0 10 20 30 40 50 85/11" 50/ 50/6" GROUND WATER LT._, SEAL LABORATORY TESTS • % WATER CONTENT DATE NP NON PLASTIC WATER LEVEL 7 AT TIME OF DRILLING "i' OBSERVATION j ♦-4'— LIQUID LIMIT L WELL TIP / '--- NATURAL WATER C:NTENT L PLASTIC LIMIT RZ4: RITTENIIOCISE -ZEM• & ASSOC., INC. , Geoteclnricnl / Ilrrlro,t;eolo,iicnl Consultants SOIL DESCRIPTION Ground Surface Elevation Approximately Feet _ Very dense, moist, gray, gravelly, silty SAND -5 Very dense, moist to wet, gray, silty fine SAND — Total depth 13'4 feet - 20 December 1988 SAMPLING 2 2. OD SPLIT SPOON SAMPLE I[ 3' OD SHELBY SAMPLE �.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED -10 t -15 -20 -25 -30 -35 I I BORING NUM 6'4 W.O. N- 5873 -1 PROJECT NAME Rainier Ridge 0 m w O Q 40 GROUND WATER L:.J SEAL STANDARD PENETRATION RESISTANCE ♦ BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 0 10 20 30 40 50 72 50/6" -- 50/5" 1 DATE 1VATER LEVEL 7 AT TIME OF DRILLING Af°L OBSERVATION L, WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC ��• --+� -- LIQUID LIMIT NATURAL WATER CONTENT PLASTIC LIMIT 1II.LJW Foe RITTENHOUSE -ZEM & ASSOC., INC. Gcoteclruical / !l�rlroge . i�ic�il Consultants SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Very dense, moist, tan, silty, sandy GRAVEL with cobbles Very dense, moist, gray sand interbedded with hard clayey SILT and silty SAND Total depth 171/2 feet 20 December 1988 SAMPLING 2 2 OD SPLIT SPOON SAMPLE 13' OD SHELBY SAMPLE F) 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED F- w w U. ✓ a w 0 0 -10 -15 -20 -25 -30 -35 40 LAB TESTS C7 z -J a. y BORING NU 6 -5 PROJECT NAME Rainier Ridge O • Q • w O a � 3 i 2 ATD w.o. W- 5873 -1 STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 lb. hammer, 30 Inch drop) 10 20 30 40 50 GROUND WATER cti SEAL DATE WATER LEVEL CV AT TIME OF DRILLING AM j OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC ��- - +`-- LIQUID LIMIT �--- NATURAL WATER CONTENT PLASTIC LIMIT A •RZA • #:•#.• RITTENHOUSE- ' 11AN & ASSOCIATES, INC. Geotechnical & gePonmental Consultants 1400 140th Avenue N.E. Bellevue, Washington 98005 -4594 (206) 746- 8020 /FAX (206) 746 -6364 • 22 March 1989 W- 5873 -1 The Holly Corporation P.O. Box 99953 Tacoma, Washington 98499 Attention: Mr. Jerry Flansburg Subject: Addendum to Supplemental Geotechnical Report Proposed Rainier Ridge Apartments Tukwila, Washington Gentlemen: This letter presents an addendum to the Supplemental Subsurface Exploration and Geotechnical Engineering Report for the Rainier Ridge Apartments, which was dated 20 March 1989. This addendum was requested by Jerry Rinker of the Holly Corporation. We understand that current foundation design concepts for the structures include either individual pile foundations, or pile supported grade beams supporting each row of columns. In our opinion, either system is capable of providing adequate foundation support for the structures. The grade beams should be located, and pile supports for the grade beams should be designed, consistent with the recommendations in the referenced geotechnical report dated 20 March 1989. In the event that higher individual pile capacities than those given in the referenced report are necessary, it may be necessary to utilize larger diameter Augercast piles, deeper Augercast piles, or cast -in -place concrete drilled shafts. Augercast piles, with a minimum length of 15 feet, and diameters of 14 and 16 inches may be designed for allowable vertical compressive capacities of 25 and 30 tons, respectively. Due to the dense nature of the site soils, Augercast drilling equipment may not be able to penetrate to deeper pile embedment in order to allow higher individual pile capacities. If high individual pile capacities are required, it may be necessary to consider cast -in -place • The Holly Corporation • 22 March 1989 W- 5873 -1 Page 2 concrete drilled shafts. These would be cast in an open or temporarily cased hole, augered to design depth with a solid flight auger. A 2 -foot diameter drilled shaft, 20 feet in length, can be designed for an allowable compressive capacity of 60 tons. The use of drilled shafts would require that the base of all holes be thoroughly cleaned of loose soil by an appropriate cleaning bucket prior to placing concrete. We trust the information in this letter has adequately summarized this additional information. Please feel free to call if you have any questions or .need additional information. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. John E. Zipper, P.E. Associate JZ:ns1 FtA RUSE -ZEMASSOCIATES, INC VI/A% Geotechnical &•dAN & rogeological Consultants . 1400 140th Avenue N.E. aidillitami Bellevue, Washington 98005 -4594 (206) 746- 8020 /FAX (206) 746 -6364 • 21 December 1988 W- 5873 -1 Holly Homes Company P.O. Box 99953 Tacoma, Washington 98499 Attention: Mr. Jerry Flansburg Subject: Summary of Geotechnical Design Recommendations Rainier Ridge Apartments: Eastern Buildings Tukwila, Washington Gentlemen: This letter summarizes geotechnical design recommendations for the three eastern buildings at the referenced project site. This letter supplements our geotechnical report for the remainder of the project W -5873 dated 15 November 1988. The additional field explorations and engineering analyses which were accomplished to develop these supplemental design recommendations were authorized on 13 December 1988, as described in our confirmation letter on that date. A Subsurface Exploration and Geotechnical Report for the three eastern buildings will be submitted when complete. Five borings were accomplished on the site, at the locations indicated on Figure 1, the Site and Exploration Plan. The borings were accomplished to depths of up to 43 feet below existing ground surface. Three of the borings were located on the slope, slightly Holly Homes Company • • W- 5873 -1 21 December 1988 Page 2 downhill of the proposed eastern edge of the apartment buildings. The borings encountered interlayered deposits consisting of very dense, silty, gravelly sand, very dense, silty, fine sand, and occasional thin, hard clayey silt interbeds. Groundwater was encountered at variable depths, generally perched above the fine grained interbeds within the sand deposit. Groundwater seepage is present at various locations on the hillside, both within the building areas and downhill of the building areas. In Tight of the interlayered stratigraphy groundwater seepage quantities, depths, and locations should be expected to be highly variable at the site, and would likely vary seasonally with changes in precipitation as well as a result of changes in site utilization. Support of the proposed easternmost buildings is considered feasible based on the subsurface conditions encountered on the site. A brief summary of the project geotechnical considerations is presented below: o We recommend the use of pile foundations for support of structures on the site slopes. Based on the soil conditions encountered in the borings, it appears that cast in place concrete auger cast piles are a suitable pile type. We recommend a minimum auger cast pile depth of 15 feet below the pile cap. We recommend that the top of pile be offset horizontally at least 5 feet from the adjacent face of slope. We recommend a design vertical compressive capacity of 20 tons for 12 inch diameter auger cast piles of the recommended depth and slope offset. Higher pile capacities can be achieved if necessary with increased pile diameters. o Lateral pile capacities are limited by the proximity of the site slopes. Lateral pile capacities will depend upon the top of pile offset from the slope face, the direction of loading, and the spacing of piles in groups. Table 1 below presents recommended lateral pile capacities for design. This table presents the capacity Holly Homes Company 21 December 1988 W- 5873 -1 Page 3 of the soil /pile interaction. Suitable reinforcing for the pile section (i.e. moment cage) would be required to fully develop these soil capacities. TABLE 1: Lateral Pile Capacities 12 -inch diameter Augercast Loading Condition Single Pile: E -W loading 5 - ft, offset to slope face E -W loading 10 -ft. offset to slope face E -W loading 15 -ft. offset to slope face N -S loading Two -Pile Group: E -W loading 3 -ft. spacing 5 -ft. offset to slope face E -W loading 8 -ft. spacing 5 -ft. offset to slope face N -S loading 3 -ft. spacing N -S loading 8 -ft. spacing Three -Plus Pile Group: 3 -ft. spacing 8 -ft spacing Ultimate Lateral Resistance (pounds) Per Pile: 5,000 7,500 10,000 12,000 Per Group: 6,500 10,000 18,000 24,000 Per Group: Two -pile group values, plus one - half of single pile resistance Sum of single pile resistance o The proposed retaining wall along the west sides of the buildings can be supported on a shallow continuous foundation bearing on undisturbed very dense soils. We recommend that the eastern edge of the footing have a Holly Homes Company. 21 December 1988 W- 5873 -1 Page 4 horizontal offset of at least 15 feet from the adjacent slope face. With this configuration, an allowable soil bearing pressure of 6,000 pounds per square foot can be used for design. A foundation base friction coefficient of 0.5, and a passive pressure equivalent fluid weight of 350 pounds per cubic foot can be used for design. These are allowable values, and include a factor of safety of at least 1.5. Active earth pressures acting on the retaining walls can be estimated as 30 pounds per cubic foot for a level ground surface. Proper drainage should be provided behind the wall, as described in our 15 November 1988 report. A surcharge should be applied to the active earth pressures to properly model inclined backfill slopes, traffic and parking loads, as well as other surcharges, located within a distance behind the wall equal to the wall height. o Excavations on the site should be expected to encounter groundwater seepage. It will be necessary to slope excavations back, blanket seepage areas with quarry spalls or rip -rap, and drain seepage away from the foundation and downhill slope areas, where encountered. Areas of excessive seepage may require well point dewatering in order to allow excavation. o Due to the site slopes and proposed building configuration, it will be necessary to provide erosion protection in areas downslope of the foundations, and in any areas exhibiting groundwater seepage. Areas which will be planted should be faced with jute or excelsior matting, and planted with appropriate deep rooted, self propagating vegetative cover. Areas exhibiting groundwater seepage, and areas extending at least 30 feet downslope of foundations, should be surfaced with at least a one foot thick layer of quarry spalls. Maintenance of erosion protection will be required throughout the life of the structure. Holly Homes Compare 21 December 1988 • W- 5873 -1 Page 5 o There appears to be minimal risk of deep seated slope instability affecting foundations on the site, provided proper design and construction procedures are followed. There is a risk of erosion and near surface soil creep. In order to minimize this risk, we recommend that no fill be placed on the existing site slopes, and that all surface water be diverted through tight lines away from the site slopes. Appropriate erosion control as discussed above is also recommended. This summary is presented for introductory purposes only and should be used in conjunction with the full text of the geotechnical report for this project, which will follow when completed. This summary should also be used in conjunction with our previous geotechnical engineering report for the upslope buildings dated 15 November 1988. This summary has been prepared for the exclusive use of Holly Homes Company, William Polk Associates, and the project designers for specific application to this project in accordance with generally accepted geotechnical engineering practices, and for use only in conjunction with the full text of the referenced geotechnical reports. Due to the preliminary nature of conceptual design drawings utilized by our firm for preparation of this report, we recommend that RZA be provided with completed design drawings when available. The design concepts and project description utilized for preparation of this summary were obtained by discussions with the project designers. In the event of any changes in the nature, design, or location of the structures, the conclusions and recommendations contained in this summary should be reviewed and modified, if necessary, to reflect the changes. Holly IHomes Compan 21 December 1988 • W- 5873 -1 Page 6 We appreciate the opportunity to provide these services. If you have any questions regarding this summary or need additional information, please do not hesitate to call. Respectfully submitted, Rittenhouse -Zeman & Associates, Inc. John E. Zipper, P.E. Associate OAS t ;104 ASy ;N.. ,p 22611 • I 49,11- $ :' 44: ultINAL Enclosures: Figure 1 - Site and Exploration Plan Boring Logs B -1 through B -5 cc: William Polk Associates, Attn: Cynthia Lohman Fossatti Associates, Attn: Lanny Flynn • RITTENHO USE -ZEMA N II .. Ceotecluricnl / Ilyilrogeohl SOIL DESCRIPTION Ground Surface Elevation Approximately ASSOC., INC. II Consultants BORING NUMBER 1 (1 of 2) W O W- 5873 -1 PROJECT NAME ainier Ridge Feet w w 2 1- a. w C.7 z J a. 0, Z • x 0 • H O et a STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) ti0 ` vv yV Loose, to medium dense, wet, mottled gray, gravelly, silty SAND -5 I IATD I S Very dense, moist to wet, gray, gravelly, silty SAND -10 _ --15 51 y 56 50/0" / Hard, moist to wet, gray, clayey SILT with some fine sand and gravel -20 -25 50/5 ".. i - -. Very dense, wet, gray, silty fine SAND -30 -35 Compressed organics at 38 feet in SILT _ interbeds - 40 50/5" 92 . _- 50/5" = 2' OD SPLIT SPOON SAMPLE I[ 3' OD SHELBY SAMPLE { 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED GROUND WATER SEAL DATE WATER LEVEL AT TIME OF DRILLING AID OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC ' • f— LIOUID LIMIT NATURAL WATER CONTENT PLASTIC LIMIT rie:Illelidit RITTENHOUSE-ZEMAN & ASSOC., INC. Gcntcchrticnl / llyt1rngenilcnl Consultants SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Very dense, wet, gray, silty fine SAND Total depth 43 feet 16 December 1988 B -1 (2 of 2) W- 5873 -1 BORING NUMBER, W O PROJECT NAlvtbainier Ridge w w 2 t— a w 40 LAB TESTS z w cc O cc a STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 10 20 30 40 50 _ 50 50/3" SAMPLING = 2' OD SPLIT SPOON SAMPLE Jr 3' OD SHELBY SAMPLE 2.5 ID RING SAMPLE 8 BULK SAMPLE * SAMPLE NOT RECOVERED GROUND WATER SEAL DATE WATER LEVEL AT TIME OF DRILLING AID OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC �% • —ate LIQUID LIMIT NATURAL WATER CONTENT PLASTIC LIMIT RITfENHOUSE -ZEMA SSOC., INC. Ccotcclrrficnl / /lyrlrogeolo, .cnl Consultants BORING NUMBEI PROJECT NAME SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Loose to medium dense, wet, brown, gravelly, silty SAND Very dense, wet, tan, silty sandy GRAVEL with cobbles F- w w co N Z la t=- 1- a o- m M w ., a o J rn 0 -10 Very dense, wet, gray, silty fine SAND Very dense, moist, tan, gravelly, silty SAND -15 -20 -25 -30 -35 . Total depth 38 feet 16 December 1988 SAMPLING = 2. OD SPLIT SPOON SAMPLE Jr 3' OD SHELBY SAMPLE I9 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED 40 GROUND WATER Z • w O Q o ATD -2 Rainier Ridge VV,O, W- 5873 -1 STANDARD PENETRATION RESISTANCE A. BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 10 20 30 40 50 82/11' 50/ 55 66 83 50/2" 50/6" SEAL DATE WATER LEVEL AT TIME OF DRILLING AED OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC —41,-- -4 •— LIQUID LIMIT 1 '---- NATURAL WATER CONTENT PLASTIC LIA1IT teeiti RI7TENHOCISE -ZEMAN �' ASSOC., INC. %6"! Gcnteclrr►icn/ / Ilyrlro,+yeolc�nl Consultants BORING NUMBE PROJECT NAME SOIL DESCRIPTION Ground Surface Elevation Approximately Feet _ Dense, moist to wet, brown, silty fine SAND Hard, wet, brown sandy SILT interbed at 8 feet F= w w 1- 0. w 0 0 -5 Very dense, moist, gray, silty fine SAPID Total depth 23 feet 19 December 1988 10 -15 -20 -25 -30 -35 ,40 LAB TESTS SAMPLING zzz • CC • - O Q o 3 W- 5873 -1 ainier Ridge STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 inch drop) 0 10 20 30 40 50 I I ✓ ATD 85/111" 50/5" 50/6" SAMPLING = 2' 00 SPLIT SPOON SAMPLE • 3' OD SHELBY SAMPLE F) 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED GROUND WATER m SEAL DATE WATER LEVEL 7 AT TIME OF DRILLING ATOo OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC 11,- -•-- LIQUID LIMIT L NATURAL WATER CONTENT PLASTIC LIMIT :77 a, RITTENIIOUSE -ZEMAN ' ASSOC., INC. Genteclrnicnl / 1/yrlrot;eoln l Consultants SOIL DESCRIPTION Ground Surface Elevation Approximately Feet Very dense, moist, gray, gravelly, silty SAND 1- w w F- a w 4-0 Very dense, moist to wet, gray, silty fine SAND Total depth 13' feet 20 December 1988 SAMPLING — I 2 00 SPLIT SPOON SAMPLE II 3' OD SHELBY SAMPLE 0 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED -10 -15 -20 -25 -30 -35 LAB TESTS CD z J a i BORING NUMBER 4 PROJECT NAME ainier Ridge z o: 0 O Q � 3 40 GROUND WATER VV.O. W- 5873 -1 STANDARD PENETRATION RESISTANCE A. BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 10 20 30 40 50 72 50/6" .... 50/5" SEAL DATE WATER LEVEL AT TIME OF DRILLING AID OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC —ate-- LIQUID LIMIT �--- NATURAL WATER CONTENT PLASTIC LIMIT RITTENIIOUSE -ZEMAN & ASSOC., INC. ,, "i�••; Grntec/rrtrcrrf / Ilyrfrn,gcn.cn/ Cnnsrr /tr1►rts u. w w I- a Ground Sur /ace Elevation Approximately Feet -0 SOIL DESCRIPTION Very dense, moist, tan, silty, sandy GRAVEL with cobbles A Very dense, moist, gray sand interbedded with hard clayey SILT and silty SAND Total depth 17'£ feet 20 December 1988 SAMPLING -- 2 2' OD SPLIT SPOON SAMPLE jr 3' OD SHELBY SAMPLE S 2.5' ID RING SAMPLE B BULK SAMPLE * SAMPLE NOT RECOVERED -5 -10 -15 -20 -25 -30 -35 LAB TESTS BORING NUMB B -5 PROJECT NA Rainier Ridge w 0. N- 5873 -1 z a rn Z° CC 7 w 0 1- a v 3 I I 40 GROUND WATER a ATD SEAL STANDARD PENETRATION RESISTANCE A BLOWS PER FOOT (140 Ib. hammer, 30 Inch drop) 0 10 20 30 40 50 DATE WATER LEVEL AT TIME OF DRILLING ATD� OBSERVATION WELL TIP LABORATORY TESTS • % WATER CONTENT NP NON PLASTIC — • -1•-- LIOUID LIMIT 1 bc-- NATURAL WATER CONTENT PLASTIC LIMIT • SUBSURFACE EXPLORATION AND GEOTECHNICAL ENGINEERING REPORT RAINIER RIDGE APARTMENTS Tukwila, Washington Prepared For Holly Homes Company W -5873 November, 1988 15 November 1988 W -5873 Holly Homes Company 8222 Washington Boulevard S.W. Tacoma, Washington 98499 Attention: Mr. Jerry Flansburg Subject: Subsurface Exploration and Geotechnical Engineering Report Proposed Rainier Ridge Apartments South 178th Street & Interstate 5 Tukwila, Washington Gentlemen: We are pleased to present herein a copy of the above referenced report.. This report presents the results of our subsurface exploration and geotechnical engineering study relative to the foundation and construction considerations for the proposed project. Authorization to proceed with this study was granted by Mr. Jerry Flansburg with Holly Homes Company, 17 October 1988. This study has been completed in general accordance with our proposal dated 17 October 1988. We appreciate the opportunity to be of service to you and would be pleased to discuss the contents of this report or other aspects of the project with you at your convenience. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. it) 6001.11., Henry W. Brenniman, Engineering Geologist Subsurface Exploration and Geotechnical Engineering Report Proposed Rainier Ridge Apartments South 178th Street & Interstate 5 Tukwila, Washington Prepared For Holly Homes Company 8222 Washington Boulevard S.W. Tacoma, Washington 98499 Prepared By Rittenhouse -Zeman & Associates, Inc. 1400 - 140th Avenue N.E. Bellevue, Washington 98005 November 1988 W -5873 1.0 SUMMARY • • TABLE OF CONTENTS W -5873 Page 1 2.0 PROJECT DESCRIPTION 2 3.0 SITE CONDITIONS 3.1 Surface Conditions 3.2 Subsurface Conditions 3 3 3 4.0 CONCLUSIONS AND RECOMMENDATIONS 5 4.1 Site Preparation 5 4.2 Structural Fill 7 4.3 Shallow Foundations 8 4.4 Slab -On -Grade 10 4.5 Wall Backfill 10 4.6 Cut and Fill Slopes 11 4.7 Surface and Ground Water Consideration 12 4.8 Recommendations for Future Study 13 5.0 CLOSURE 13 Figure 1 - Site and Exploration Plan Appendix A - Subsurface Exploration Procedures and Logs • • SUBSURFACE EXPLORATION AND GEOTECHNICAL ENGINEERING REPORT RAINIER RIDGE APARTMENTS SOUTH 178TH STREET & INTERSTATE 5 TUKWILA, WASHINGTON 1.0 SUMMARY The proposed project is considered feasible based on the subsurface conditions encountered on the site. A brief summary of the project geotechnical considerations is presented below: o A total of nine backhoe test pits were excavated across approximately the west -half of the parcel. No explorations were conducted below the break in slope. Test pits on the south - central portion of the parcel disclosed subsurface conditions consisting of topsoil over loose to medium dense, silty sand underlain by a medium stiff to very stiff, sandy silt. These strata overlie a dense, gravelly sand to sandy gravel. Test pits for the remainder of the parcel disclosed subsurface conditions consisting of topsoil over loose to medium dense, gravelly, silty sand, all underlain by dense glacial till at depth. A thin wedge of uncontrolled fill was encountered at the east edge of the existing parking area. G We observed no evidence of major slope instability during our site visit. We did observe some topographic evidence of previous minor surfici -al instability below the break -in -slope on the east side of the site due to the erosion of sands. The slope did not appear to have been altered by previous grading, with the exception of tree cutting and vegetative debris pushed downslope. At the time that our scope of work was developed for this project, no structures were reportedly planned below the break in slope. Additional subsurface explorations are recommended for building structures below the break -in -slope to determine depth to footings, setback for footings and bearing pressures. O Ground water seepage was observed in three of the test pits during our explorations. The seepage was below 7 feet in depth. Perched ground water may develop above the glacial till soils during wetter portions of the year. Also, ground water seepage was observed in the sands occurring below the break -in- slope, which should be controlled to minimize erosion. O Shallow spread footings are considered feasible for the western three buildings. We recommend utilizing a maximum allowable soil bearing pressure of 2500 psf for buildings founded on structural fill, stiff to very stiff Holly Homes Company /Rain er Ridge Apartments 15 November 1988 W -5873 Page 2 sandy silt or the medium dense to very dense native till soils. If desired, higher bearing pressures are available for footings bearing directly on dense to very dense native till soils. This summary is presented for introductory purposes only and should be used in conjunction with the full text of this report. The project description, site conditions and detailed geotechnical design recommendations are presented in the text of this report. Exploration procedures and logs are presented in Appendix A. 2.0 PROJECT DESCRIPTION The proposed project encompasses an area of approximately 6.6 acres, located at the northeast corner of the South 178th Street overpass on Interstate 5 in Tukwila, Washington. We understand, according to the plans provided to us, that the property will be developed for seven multi -unit, three -story wood - framed apartment buildings with daylight- basements, adjacent clubhouse and swimming pool. The parcel is roughly trapezoidal in shape, extending approximately 580 feet along South 178th Street on the south side. The eastern and western property lines extend approximately 760 feet and 450 feet, respectively. The northern property boundary extends approximately 420 feet east to west. The parcel will be serviced by an entrance drive off South 178th Street. Proposed building and access road locations as well as the approximate locations of the explorations accomplished for this study are shown on the Site and - Exploration Plan, Figure 1. The purpose of this evaluation is to establish general surface and subsurface conditions at the site from which foundation design and site improvement recommendations could be formulated. The scope of work consisted of field explorations, visual assessment of site conditions, geotechnical engineering analyses and report preparation. The scope of field exploration was limited to the area west of the break in slope identified on Figure 1, based on information provided to us at the time our scope of work was proposed. In the event that any changes in nature, design, or location of the structures is planned, the conclusions and recommendations contained in this report should be reviewed and modified if Holly Homes Company /Rainier Ridge Apartments • W -5873 15 November 1988 Page 3 necessary to reflect the changes. This report has been prepared for the exclusive use of Holly Homes Company and their agents, for specific application to this project in accordance with generally accepted geotechnical engineering practices. 3.0 SITE CONDITIONS The site conditions were evaluated on 19 October 1988. The surface and subsurface conditions are described below, while the exploration procedures and interpretive logs of the explorations are presented in Appendix A. 3.1 Surface Conditions The site is comprised of two areas, the western, gently sloping, upper plateau and the eastern steep slope. These two areas are bisected by a break -in -slope trending southeast to northwest. Topographic relief across the upper, western portion of the property ranged from elevation 270 feet to 235 feet. Below the break -in- slope, the eastern portion of the property slopes down at approximately a 2H:1V slope towards Southcenter Parkway. The upper, western portion of the site had been stripped at the time of our exploration of most of the brush and trees. An access road leading to a demolished building foundation remained in the stripped area. The access road continued beyond the north end of the property to a concrete slab and parking area off the site. The vegetation on the eastern, steep slope was relatively undisturbed and consisted of maple, apple, alder and fir trees with an understory of blackberry, ferns, salal and brush. No standing surface water was observed on -site at the time of our investigation. Some water seepage was observed from the hillside below the break -in -slope in the center of the site. Water appeared to be coming from a fine - grained sand which lies below the glacial till. 3.2 Subsurface Conditions Due to the limited access to the site and preliminary project description, our explorations were confined to the western portion of the property located above • • Holly Homes Company /Rainier Ridge Apartments W -5873 15 November 1988 Page 4 the break -in- slope. Only a visual observation was made of soils on the slope. In general, with the exception of the south - central region of the site, where test pits TP -1 and TP -9 were excavated, subsurface conditions appeared to be relatively uniform. At depth, all explorations encountered dense, glacially overconsolidated, gravelly sands to sandy gravels with some silt or dense to very dense glacial till soils. In the south - central region of the site, soils in test pits TP -1 and TP -9 consisted of 1/2 to 1 foot of topsoil, overlying 1/2 foot of loose to medium dense, moist to wet, silty, fine sands. Underlying these soils were 3 to 5 feet of medium stiff to very stiff, wet, orange and gray, sandy silts to a depth of 4 to 6 feet. These soils were found to overlie the dense, moist to wet, tan, gravelly sands to sandy gravels with some silt. On the remainder of the upper portion of the parcel, test pits TP -2 through TP -8 encountered 1/2 to 1 -1/2 feet of topsoil overlying 1 to 3 feet of a medium dense, moist to wet, tan, gravelly silty sand (weathered till). These soils overlie a dense to very dense, moist, grayish -tan, gravelly silty sand (glacial till) to the bottom of our explorations with the exception of test pit TP -3. At 4.5 feet in test pit TP -3, our exploration extended through the glacial till and penetrated into dense, moist to wet, tan, gravelly sand to sandy gravel with some silt. Test pit TP -2 encountered 2 feet of medium dense, wet, brown, silty, gravelly sand (fill) over the native soil. The glacial till and all soils stratigraphically below, have been overridden in a geologic past by the glacial ice mass, compressing the soil with the weight of thousands of feet of glacial ice. As a result, the soils exhibit both high strength and low compressibility characteristics. Below the break -in -slope we observed silty sands underlying the glacial till at depth, but were unable to locate the contact of the strata. These fine - grained soils should be considered highly susceptible to erosion due to ground water seepage and surface water runoff. Additional explorations will be necessary below the break -in -slope in order to determine the subsurface conditions on the slope and to provide recommendations for depths to foundation subgrades, set back from the slope face and bearing pressures. • • Holly Homes Company /Rainier Ridge Apartments 15 November 1988 W -5873 Page 5 Subsurface seepage was observed in test pits TP -1, TP -2 and TP -3 at depths of 11, 7, and 8 feet, respectively. It should be noted that our explorations were performed at the end of the dry season and more extensive seepage may occcur during winter and spring. Typically, subsurface seepage percolates down and becomes perched upon and above the grayish -tan, dense to very dense glacial till. It should be noted that subsurface seepage volumes and ground water conditions may fluctuate due to variations in site utilization, season, rainfall and other factors. Also, during our visual observation of the hill slope below the break -in- slope, we observed water seeping out of the hillside near the center of the site and it will have to be controlled prior to construction on the slope. 4.0 CONCLUSIONS AND RECOMMENDATIONS Development plans call for the construction of seven two -story or three - story, plus daylight- basement, wood - frame, multi - family buildings, along with office /recreation center and outdoor swimming pool. The development would also include ancillary parking, drives and landscaping. In our opinion, the development as proposed is feasible from a geotechnical standpoint. The subsurface conditions as encountered in the explorations are considered suitable for spread footings, continuous wall footings and slab -on -grade floor support. Proper site preparation and drainage of the site, both temporary and long -term, will be necessary to minimize cost and provide proper adequate long -term performance of the facilities. Subsurface soils are generally in a dense condition, .and the risk of deep- seated instability of the slope is considered minimal in its present condition. Additional explorations will be required for development of the steep slope area. 4.1 Site Preparation Prior to site development, the contractor should implement a temporary erosion control plan. Such an erosion - control plan should divert runoff away from the surrounding steep slopes and areas to be exposed during grading, and should prevent sediment from being transported off the site. Areas which will be graded for roads, driveways, buildings and sidewalks, should be cleared and stripped of vegetation, surficial topsoil and fills, and dense root accumulations. Vegetation Holly Homes Company /Racer Ridge Apartments 15 November 1988 • W -5873 Page 6 can be removed from the site and wasted or stockpiled for landscaping purposes. No stripped material or other soil material should be pushed over the surrounding steep slopes. Any material spilled over these slopes would be susceptible to initiating slope erosion. The topsoil and other organic soils stockpiled as a result of clearing, would not be suitable as structural fill. Based on our explorations, we estimate stripping depths to remove organic -rich surface soils may range from about 1/2 to 1 -1/2 feet, although greater depths of excavation may be necessary locally, especially for removal of large trees, stumps, or existing structures. Approximately 2 feet of uncontrolled fill underlies the east side of the existing parking lot, as noted in test pit TP -2. All uncontrolled fill should be removed prior to placement of structural fill. Any old footings remaining from the demolished structure should also be removed from the subgrade prior to placement of structural fill. After stripping, the resulting exposed subgrade soils will contain a high percentage of fines. Thus, it will be highly susceptible to disturbance when damp or wet. For this reason, earthwork should be scheduled for the dry, summer months all possible. If stripping is done while the ground is wet, the volume of topsoil, soft wet soils, or disturbed soils to be removed, can be greatly increased. The contractor should employ construction procedures and equipment such that disturbance can be minimized, thus controlling the quantity of material to be excavated. Those areas which are excavated to design or subgrade elevations or areas to receive "structural fill ", should be prerolled as necessary to at least 90 percent density, using ASTM :D 1557 as a standard. If the subgrade is more than a few percent above its optimum moisture content, adequate compaction will be difficult or impossible to achieve. It may be necessary to scarify the upper layer, allow it to dry, then recompact. If localized areas of soft subgrade, pumping ground or organic -rich soils are encountered during stripping, these areas should be overexcavated and backfilled with structural fill as recommended below. • PROPOSED PARKING (TYPICAL) B -1 B -5 PROPOSED APARTMENT BUILDING (TYPICAL) EXPLANATION B- B-5 INDICATES BORING NUMBER AND ® APPROXIMATE LOCATION DRAWING BASED ON FAX BY WILLIAM POLK ASSOCIATES 21 DEC 1988. 0 60 120 APPROXIMATE SCALE IN FEET RAINIER RIDGE APARTMENTS TUKWILA, WASHINGTON SITE & EXPLORATION PLAN FIGURE W.O. W- 5873 -1 BY JZ DATE DEC 10118 SCALE _NOTED RITTENHOUSE -ZEMAN & ASSOCIATES. INC. RZA 11.7 vie Geotechnical & Hydrogeological Consultants 1400140th Avenue N. E. 1101 k Bellevue. Nuhington 98005 Holly Homes Company /Rainier Ridge Apartments W -5873 15 November 1988 Page 7 If wetter portions of the site are encountered, and wet subgrade soils cannot be dried to a suitable moisture content, it may not be feasible to compact the subgrade by prerolling. In this case, at the descretion of the geotechnical engineer, the subgrade should be cleaned of soft soils to a firm native soil and a layer of clean sand and gravel, quarry spalls or crushed rock should be placed prior to applying compaction. 4.2 Structural Fill All fill placed in building areas as well as under parking lots, drives and sidewalks, and for the backfill of utility trenches, should be placed in accordance with recommendations outlined herein for "structural fill" and any City of Tukwila or King County compaction requirements where applicable, for roadway and sewer construction which may supercede these recommendations. Prior to placement of structural fill, all surfaces to receive fill should be prepared as previously recommended. Structural fill should be placed in lifts not exceeding 8 inches in loose thickness. Individual lifts should be compacted such that a density of at least 90 percent of the modified Proctor maximum dry density (ASTM: 1557) is achieved. We recommend that a representative of our firm be present during placement of structural fill to observe the work and perform a representative number of in- -place density tests. In this way, the adequacy of the work may be evaluated as grading progresses. The suitability of soils for structural fill use depends primarily on the gradation and moisture content of the soil when it is placed. Any soil to be used as structural fill should be free of organics and other deleterious material. As the amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. Soil containing more than 5 percent fines by weight cannot be compacted to a firm, non - yielding condition when moisture content is more than a few percent above optimum. • • Holly Homes Company /Rainier Ridge Apartments W -5873 15 November 1988 Page 8 The existing topsoil at the site is not considered suitable for structural fill use, but could be stockpiled for later use in landscaped areas. We anticipate the remaining surficial site soils that would be available for fill as a result of site grading, could consist primarily of gravelly silty sand and sandy silt with gravelly sand and sandy gravel being present at depth at the south - central end of the site. The majority of the near - surface on -site soils contain more than 5 percent fines and would be considered moisture - sensitive. These siltier on -site soils would not be suitable for use as structural fill during wet weather. Any silty soil would only be suitable for use during extended periods of dry weather, within dry portions of the site. If rain were to occur while the silty soils are exposed, or during placement of this material, or any other soils with over 5 percent fines, the exposed material should be allowed to dry prior to additional filling. It may be necessary to scarify the upper layer, allow it to dry, and then recompact prior to additional filling. It may also be necessary to overexcavate and remove wet soils if it is not practical to dry and recompact them. If the silty soils cannot be used for structural fill due to their moisture content or weather conditions, it may be expedient to import a "clean" granular material for structural fill use. Clean, imported soils should contain no more than 5 percent (by weight) material passing through the U.S. No. 200 sieve, when measured on the minus No. 4 sieve fraction. Cleaner soils of this type may be successfully placed and compacted under a wider variety of weather conditions. In all cases, soil used for structural fill should have a maximum particle size on the order of 6 inches and be free of organics and other deleterious materials. 4.3 Shallow Foundations Conventional shallow spread and continuous footings may be utilized for the support of the proposed structures, provided any existing topsoil, loose soils, or other materials containing organics are removed from within the foundation areas. Footings may be constructed on either undisturbed, stiff to very stiff, sandy silt, dense, gravelly sand, medium dense to dense weathered till or 90 percent minimum density structural fill placed above suitable native soil deposits. Suitable • • Holly Homes Company /Rainier Ridge Apartments W -5873 15 November 1988 Page 9 bearing soils were encountered at depths of 1 to 2 feet in our test pits. We recommend the foundation be designed for a maximum allowable soil bearing pressure of 2500 pounds per square foot (psf). If higher bearing pressures are required, footings may be founded in the dense to very dense native glacial till soils and additional recommendations can be provided. This allowable bearing pressure may be increased by up to one -third to accommodate seismic or other transient loads. All footings should be founded in the prescribed bearing strata, and should have a minimum width of 18 inches. The base of the exterior footings should extend at least 18 inches below the lowest adjacent ground level or the top of the floor slab, whichever is lower. Interior footings should extend 12 inches or more below the surrounding grade or slab surface. All footings must penetrate into the prescribed bearing stratum and foundations should not be set in or above any loose or disturbed soils, topsoil, non - structural fill or any uncontrolled fill. As some of the site soils are silty, site work in the presence of water or during wet weather may disturb the bearing strata. The contractor should avoid disturbance of these soils and limit traffic across the building pads or foundation areas during wet weather. To minimize disturbance associated with foundation formwork and reinforcement bar placement, the use of a "mud mat" or quarry spall blanket may be required. We estimate foundation settlements may be on the order of 1 inch or less with differential settlement equal to one -half of that total. If loose or soft materials are left within the foundation areas prior to concrete placement, future settlements may be increased. For that reason, the condition of the footing subgrade should be closely monitored prior to concrete placement to confirm that the conditions of the bearing soils are consistent with those assumed during design. If loose or soft soils are left within the foundation areas prior to concrete placement, settlements may be increased. Therefore, we recommend that all footing subgrade soils be observed by the project geotechnical engineer prior to concrete and reinforcement bar placement. Holly Homes Company /Rainier Ridge Apartments 15 November 1988 • W -5873 Page 10 4.4 Slab -On -Grade The, slab -on -grade floor subgrade should be prepared in accordance with previous Site Preparation recommendations. Slab -on -grade floors should be founded on prerolled native ground or structural fill placed and compacted as per our recommendations outlined previously. We recommend that the floor slab be underlain with a minimum of 6 -inch thickness of clean sandy gravel, crushed rock, or pea gravel to serve as a capillary break and working surface. An impervious moisture barrier should also be placed beneath the slab. To protect the membrane from punctures associated with reinforcement placement, the Portland Cement Association recommends at least 2 inches of sand between the vapor barrier and the concrete slab. Ground water seepage was encountered in test pits on the site. It may be necessary to provide subsurface drains below floor slabs or in crawlspaces, for buildings which are located below existing grades. We recommend that the final recommendation regarding locations and depths of subfloor drains be made by RZA, Inc. during construction, on a building- specific basis. These final recommendations would be based on the ground water conditions encountered at each buildings site. 4.5 Wall Backfill Retaining walls constructed that allow some deflection during backfill placement may be designed to resist a lateral force equivalent to a fluid weighing 35 pounds per cubic foot (pcf). Walls that are structurally restrained from lateral movement at the top may be designed with an equivalent fluid unit weight of 50 pcf. A minimum width of 2 feet of clean granular backfill should extend from the base of the wall up to the ground surface which can communicate freely with the wall footing drain. This drainage layer is intended to preclude the buildup of hydrostatic forces. The value for the allowable passive earth pressure of 250 pounds per cubic foot may be assumed for each foot of penetration below the ground surface, neglecting the first foot. An allowable wall base friction value of 0.40 is recommended. We recommend that we be retained to review the design values if they are to be applied to walls greater than 12 feet in height. Holly Homes Company /Rai /l'rer Ridge Apartments 15 November 1988 • W -5873 Page 11 All backfill placed behind walls should be placed as per our structural fill recommendations of this report. The previously recommended earth pressures presented as equivalent fluid unit weights are based on an assumption of uniform level granular backfill and no buildup of hydrostatic pressure behind the wall. To minimize lateral earth pressures and prevent the buildup of hydrostatic pressures, the wall backfill should consist of free - draining granular material with drainage provisions as discussed subsequently in this report. We recommend that the silty on -site soils not be used as backfill directly against walls. Surcharges due to sloping ground, adjacent footings, vehicles, construction equipment, etc., must be added to these values. The above equivalent fluid unit weight assumes the backfill is compacted to approximately 90 percent of the modified Proctor laboratory maximum dry density (ASTM:D 1557). Additional compaction adjacent to the wall will increase the lateral pressures, while a lesser degree of compaction may permit excessive post - contruction settlement. It should be noted that limitations placed on compaction may allow some minor settlement on the wall backfill with time. Typically, this is not a problem, except for settlement - sensitive surfaces or structures which are founded in the backfill. 4.6 Cut and Fill Slopes We recommend that permanent cut slopes on the western portion of the property above the ground water table be designed with a maximum slope of 2H:1V (Horizontal:Vertical). Permanent fill slopes may also be constructed with an inclination of 2H :1V. The surface of the embankment should be compacted to the same 90 percent density as the body of the fill. This may be accomplished by overbuilding the embankment and cutting back to its compacted core. Cut -away material should, however, be removed from the fill slope. Alternatively, the surface of the fill slope may be compacted as it is built. Fill placed on slopes steeper than 5H:1V should be keyed and benched to the existing firm, stable soils. All slopes should be protected from runoff by berms, swales, and if necessary, an impervious cover. We recommend hydro- seeding exposed cut or fill slopes to reduce Holly Homes Company/Rainier Ridge Apartments W -5873 15 November 1988 Page 12 the potential for erosion. If erosion occurs on any slope, the use of a layer of quarry spalls or sandy gravel may be required across the surface of the slope to mitigate additional erosion. 4.7 Surface and Ground Water Consideration Surface and groundwater management should provide storm water detention facilities of sufficient capacity to essentially duplicate pre - development runoff rates across the site. In addition to providing detention facilities to handle storm runoff, the designated drainage pathways may need to be provided with protection against increased flow velocity and associated erosion. Gullying of soils can be prevented by terracing the channel bottom, or installing a series of controll structures such as weirs, along the drainage path. Soils along the drainage path can be protected further by lining the surface of the channel with non - erodable material, such as large rock. The actual increased runoff due to the site development and requirment structures for erosion control should be determined by a qualified civil engineer. In our opinion, the use of dry wells for storm water infiltration would not be appropriate at this site due to the silty and dense natures of the underlying soils, and the proximity to the steep slopes. Dispersal or retention of storm water along existing drainage pathways on -site may be appropriate. The site soils are silty and highly susceptible to disturbance when wet. Prior to construction any site surface or ground water should be routed away from the construction and the building areas to minimize disturbance. Due to the possibility of developing a perched ground water condition, we recommend that the buildings be provided with a perimeter footing drain system to collect available water. Footing drains should consist of a perforated pipe fully enveloped by at least 6 inches of pea gravel or washed rock. The drains should discharge into a tight - line drain network away from the buildings via gravity to a suitable discharge point. Site grades should be planned to direct surface water away from the buildings and slopes and to avoid ponding. Roof and surface runoff should not be discharged in the footing drain system; instead, a separate tight -line drain network should be installed or splash blocks should be used to direct storm water away from the completed buildings. • • Holly Homes Company /Rainier Ridge Apartments 15 November 1988 W -5873 Page 13 4.8 Recommendations for Future Study The scope of work for this study was limited to the portion of the property upslope of the break in slope designated on Figure 1. In order to provide geotechnical engineering recommendations for building foundations below the break -in- slope, we recommend that additional explorations be conducted. This would involve digging several test pits with a backhoe or using a portable drill rig to explore this portion of the site in order to develop additional recommendations regarding depth to footings, slope setback of footings, and bearing pressures. Backhoe pits would require dozer work to provide an access road to the necessary locations on the slope. 5.0 CLOSURE The conclusions and recommendations presented in this report are based on the explorations accomplished for this study. The number, location and depth of the explorations were completed within the site and scope of constraint so as to yield the information necessary to formulate our recommendations. The integrity of the foundations depend on proper site preparation and construction procedure. If variations in the subsurface conditions are observed during construction, we would be able to provide additional geotechnical services during the project development. The proposed development appears to be feasible with adequate care addressed to site stripping, drainage and slope configuration. We appreciate this opportunity to be of service. If you should have any questions, please do not hesitate to call. Respectfully submitted, RITTENHOUSE -ZEMAN & ASSOCIATES, INC. / 64.24,t/KG7ria.— Henry W. Brenniman, Engineering Geologist John E. Zipper, P.E., Associate EXPLORATION TP, 9 INDICATES TEST PIT NUMBER AND 0 — APPROXIMATE LOCATION PROPOSED CLUB HOUSE & POOL EXISTING ACCESS TP -1 `TP - EXISTING PARKING TP -8 INTERSTATE 5 PROPOSED PARK /N G (T YP/CAL) TP -3 BREAK IN SLOPE EXISTING 16' H.P. GAS LINE 7 PROPERTY LINE BAS ED ON DRAWING BY WILLIAM POLK ASSOCIATES, UNDATED. 0 60 120 APPROXIMATE SCALE IN FEET TP -7® TP -4a PROPOSED (TYPICAL) APARTMENT BUILDING zl> TP -6 RAINIER RIDGE APARTMENTS TUKWILA, WASHINGTON SITE & EXPLORATION PLAN FIGURE 1 W.O. BY DATE SCALE W -5873 HWB NOV 1988 NOTED RITTENHOUSE -ZEMAN & .ASSOCIATES, INC. ' Geotechnical & Hydrogeological Consultants 1400 140th . -venue :V. E. Bellevue. tlitshingtrnt 9S()05 RZA 70:044411: • • APPENDIX A SUBSURFACE EXPLORATION PROCEDURES AND LOGS • • APPENDIX A W -5873 Field Exploration The field exploration program conducted for this study consisted of excavating nine test pits. The approximate exploration locations are illustrated on the Site and Exploration Plan, Figure 1. The exploration locations were obtained in . the field by taping from site features shown on a plan provided by Holly Homes Company. The locations of the explorations should be considered as accurate as the degree implied by the method used. Test Pit Excavations Nine test pits were excavated on 19 October 1988 with a rubber -tired backhoe by a local excavating contractor. Each test pit was continuously logged and observed by one of our experienced engineering geologist. In -situ strength and quality attributes of materials encountered in the test pits were estimated by our field observer based on experience with similar soils and on the difficulty incurred during excavation. Disturbed, but representative, samples of the soils in the test pits were retrieved, classified in the field, and transported in plastic containers to our laboratory for further evaluation and classification. The test pit logs are presented in this appendix and are based on the inspection of the samples secured and the field logs. • TEST PIT LOGS Depth (feet) Soil Classification 0.0 - 0.5 0.5 - 1.0 1.0 - 4.0 4.0 - 6.0 6.0 - 6.5 6.5 - 8.0 8.0 - 11.5 0.0 - 0.5 0.5 - 2.0 2.0 - 2.5 2.5 - 4.0 4.0 - 8.0 Test Pit TP -1 W-5873 TOPSOIL, loose, wet, brown, gravelly, silty SAND with organics and substantial roots Loose to medium dense, wet, light tan, silty, fine SAND with moderate roots Medium stiff grading to stiff, wet, mottled orange -tan, clayey SILT with some fine sand Dense, moist, tan, silty, gravelly SAND with cobbles Very dense, moist, mottled orange -tan, silty, gravelly SAND Dense, moist, yellow -tan, silty, gravelly, medium to coarse SAND Dense, moist grading to wet, tan, gravelly SAND to sandy GRAVEL with cobbles and some silt Sight seepage at 11 feet Slight caving at 10 -1/2 feet Test Pit TP -2 TOPSOIL, loose to medium dense, wet, brown, gravelly, silty SAND with organics Medium dense, wet, brown, silty, gravelly SAND with organics (Fill) Medium dense, wet, bluish -gray, silty, gravelly SAND Dense, moist, tan, silty, gravelly SAND Dense, moist, gray to wet, tannish -gray, silty, gravelly SAND (Glacial Till) Slight seepage at 7 feet Test Pit Logs Page 2 Depth (feet) 0.0 - 0.5 0.5 - 1.0 1.0 - 3.0 3.0 - 4.5 4.5 - 6.5 6.5 - 9.0 4.0 - 8.0 • • W -5873 Soil Classification Test Pit TP -3 TOPSOIL, loose, wet, gravelly, silty SAND with organics with substantial roots Loose to medium dense, wet, orange, gravelly, silty SAND with substantial roots Medium dense, wet, mottled orange -tan, gravelly, silty, fine to medium SAND with cobbles (Weathered Till) Dense, moist to wet, tan, silty, gravelly SAND with cobbles (Glacial Till) Dense, moist to wet, yellow -tan, silty, gravelly SAND with cobbles Dense, wet, tan, silty, gravelly SAND to sandy GRAVEL with cobbles Slight seepage at 8 feet Slight caving at 8 feet Test Pit TP -4 TOPSOIL, loose, wet, black, gravelly, silty SAND with substantial roots Medium dense, wet (top 6 inches), damp to moist (remainder), mottled orange -tan, silty, gravelly SAND with scattered roots (Weathered Till) Dense, damp to moist, tan, silty, gravelly SAND (Glacial Till) Test Pit Logs Page 3 W -5873 Depth (feet) Soil Classification Test Pit TP -5 0.0 - 1.5 TOPSOIL, loose, wet, brown, gravelly, silty SAND with substantial roots 1.5 - 4.0 Medium dense, damp to moist, tan, silty, gravelly SAND (Weathered Till) 4.0 - 6.0 Dense to very dense, moist, grayish tan, gravelly, silty SAND (Glacial Till) 0.0 - 1.0 1.0 - 3.0 3.0 - 6.5 0.0 - 1.0 1.0 - 2.5 2.5 - 5.5 5.5 - 7.5 Test Pit TP -6 TOPSOIL, loose, wet, brown, gravelly, silty SAND with some organics Medium dense, damp to moist, light tan, gravelly, silty SAND with scattered to moderate roots (Weathered Till) Dense, moist, grayish -tan, gravelly, silty SAND (Glacial Till) Test Pit TP -7 TOPSOIL, loose, wet, brown, gravelly, silty SAND with organics and moderate roots Medium dense, moist, tan, gravelly, silty SAND with scattered roots (Weathered Till) Dense, moist, grayish tan, gravelly, silty SAND (Glacial Till) Dense, moist to wet, tan, silty, gravelly, fine to medium SAND with cobbles (Glacial Till) Test pit was excavated on slight slope to the south • • Test Pit Logs Page 4 W -5873 Depth (feet) Soil Classification 0.0 - 1.0 1.0 - 2.0 2.0 - 7.0 0.0 - 1.0 1.0 -1.5 1.5 - 4.0 4.0 - 6.0 6.0 - 10.5 Test Pit TP -8 TOPSOIL, loose, wet, brown, gravelly, silty SAND with organics and scattered roots Medium dense, damp to moist, tan, gravelly, silty SAND with scattered roots (Weathered Till) Dense, moist, grayish tank, gravelly, silty SAND (Glacial Till) Test pit excavated on hillside sloping to the east Test Pit TP -9 TOPSOIL, loose, wet, brown, gravelly, silty SAND with organics and roots Medium dense, wet, tan, silty, fine SAND with trace of gravel and scattered roots Stiff grading to very stiff, moist, mottled orange -tan, fine, sandy SILT to silty, fine SAND, with trace of gravel Very stiff, moist, gray, fine sandy SILT Very dense, moist, orange -tan, silty, gravelly SAND to sandy GRAVEL with cobbles Test pit was excavated on hillside sloping to the east City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 OZ06) 433 -1800 Gary L. VanDusen, Mayor TO: FROM: DATE: SUBJECT: MEMORANDUM Pet. 4� I 'M4trn P (Pikilif°07745) Daame CkliffLrl Pig 00 Pictg541c-Re._ Fd1d1bl'7 s 1 tots ed i31 iI R,11 TJ is hd€ 4 T41 k1' 14;144 I JCtd Aiterf Tie LOY,AAO yterhAttagbii f/1;c f /'i /-)t I Ids )s our 5-kYie..S• t 014_Aff le.h vuorg. (10 /T2.MEMO) i of • • ila City PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433-1849 CHECKLIST PLANNING DEPARTMENT (Land Use) FOR STAFF USE ONLY Pre -app File # PRE- APP - 027 -88 Project Name: Rainier Ridge Meeting Date 11 -10 -88 Time 2:30 pm Site Address: NW Corner Southcenter Parkway Zoning P- O /R -1 -12 S 178th St LAND USE INFORMATION _ Compliance with the Zoning Code (Title 18). 0 2. Obtain the following permits /approvals: (applications attached) Q 3. — Boundary Line Adjustment — Building Site Improvement Plan Comprehensive Plan Amendment Conditional Use Permit j - Design Review Design Review - Interurban ,/Environmental (SEPA) Planned Mixed Use Development Proposed use complies with zoning? Planned Residential Rezone Shoreline Management Shoreline Management Short Subdivision Subdivision Unclassified Use Variance, for Q 4. Structure meets setback requirements? 1.4(^/(^4(/....A Development Permit Permit Rev. °Yes No Yes _ No Q 5. Proposal meetings minimum parking space standards? �es — No Q 6. Roof -Top mechanical equipment screened? T f64o2"` Yes No KING/ Sofa— — Q 7. Site plan complies with landscape requirements. Yes No /VLF °°ve- Q 8. Goss('Ce Dome AMavb. peaEf/$ /Yin(G P2.oPosgt. uSE-- Q 9. $7'4 - w /cc- ,e &, G6-o Emus #e'D a7 [C c="AtlY3 Q 10. /Vo pRoajt gr ■I6EI) Fop_ 20 / SCr/ACK F,eoa1 EroGe- of Q 11. Sc oPe" Perk Ge ore-c, Q 12. f4 -tell Co viki f 71) Srd�� Q 13. ACC- vH PS rC2S 7-o Fe" Fo C Y Sc,2eLruED Q 14. LAKDSGA -e /t(G 0PAQU MArg /4C S Q 15. 13LDG (G k -- g677 n- /sc taG Niccs/ "z)� - Q 16. -FIZA-rtS(Y/o,-! 7o SANG C,( (Y A-ta S S,Gn,,F, Q 17. C A, /7t ` F /A/6/2-6/7454D Ve27: 110R-(-F , Nl a b 61 CO 7 ?o,/ • 7-0 Q 18. /3teAK OP C-.)4(-c, FA-Gel T/e..c A 4--°'G P &R,1-1 re' Q 19. /Vet' Dutm Ps7-672S 4, /N - / of Pia° p f72 (Y L /rtg (Su( -. D Q 20. 0q O / S sTV D i i? AS 1)412--r- a r s cP4 , .{-r us T 09,1 5771A D4bs 4-geAS j (SP, oc r-s7 ,erc, Aiz.e 2 S Checklist prepared by (staff): ti` Date l( /k" (7-ut.A.Y Sc 2evh/ FE7'/Ce" d- C. A-o ckp /Nc, v • a w " kits, City of Tukwila 1908 PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila. Washington 98188 (206) 433 -1849 PRE- APPLICATION CHECKLIST BUILDING DIVISION (construction) FOR STAFF USE ONLY Pre -app File # PRE- APP - 027 -88 ti _project=_Name4Rainier Ridge Meeting Date 11 -10 -88 Time 2 :30 pm Site Address: NW Corner Southcenter Parkway/ S 178th St Occupancy Group R -1 CONSTRUCTION INFORMATION 0( 1. Comply with the provisions of the Uniform Building Code, 1985 Edition (as `"" amended). 2. Comply with Washington State Barrier Free. Code, 1987 Edition. 3. Comply with Uniform Mechnical Code, 1985 Edition. 4. Comply with State Energy Code. Provide energy calculations stamped by a III��"` Washington State Licensed architect or engineer. 5. Provide licensed Washington Architect stamp on construction drawings. 6. Provide a soils report, stamped by a Washington State licensed engineer. g 7. Submit structural calculations stamped by a Washington State licensed struc- tural engineer. 8. Obtain building permit. ‘i5R( 9. Obtain mechanical permit. Roof top mounted equipment requires structural calculations stamped by a licensed engineer. C1 10. Obtain grading /fill permit. ▪ 11. Obtain separate permit for rack storage. Rack storage must be designed for ,seismic zone 3. A licensed structural engineers stamp will be required for rack storage 8' and over. [[ 12. Obtain a sign permit (TMC Title 19). cEl 13. SppciAl ins inspgstorseZ1 be required *en- 0.15 5i4104V i e c. , 3)(7 Ulfikr444 <Par 14. Notify Building Official of testing lab hired by architect or owner (not by contractor). 15. Obtain approvals and permits from outside agencies (see attached misc. and outside agencies checklist). • Electrical permit and inspections through Washington State Department of Labor and Industries, 872 -6012. • Plumbing permit and inspections through King County Health Department, 587 -2732. [� 16. King County Health Department must approve and stamp plans for restaurants and food service facilities prior to submittal to Tukwila Building Division. 0 17. Provide plan submittal per requirements on attached plan submittal handout. 5 18. /UkuJ /id& n1/ 1c'1a14cQ / ►i1 rir `'1. Pretr� bud/ 6 , pl 19. -7-47, 0YOY W 5- _4v ,ie� Jf /bar/fie/ [CC( Q 20. - • (4ze.42- is 110 Checklist prepared by (staff): Date //-/O-?F F City of Tukwila FIRE DEPARTMENT 444 Andover Park East Tukwila. Washington 98188-7661 (206) 575-4404 PRE— APPLICATION CHECKLIST FIRE DEPARTMENT (inspections) FOR STAFF USE ONLY Pre -app File # PRE - APP - 027 -88 Project Name: Rainier Ridge Meeting Date 11 -10 -88 Time 2:30 pm Site Address: NW Corner Southcenter Parkwa S 178th St Occupancy Group R -1 INSPECTIONS REQUIRED BY•FIRE DEPARTMENT Q 1. Underground fire line from vault to riser a. Thurst block and rodding b. Type of pipe c. Depth of cover d. Flush e. Hydrostatic test f. Fire Dept. approved plans g. Materials and test certi- ficate -2. OverFi'eda- Spv9?Ikler piping a. Hydrostatic_ test b. Trip test c. Alarm.system monitoring _. - d. Fire Dept... approved plans e. Sprinkler head.locattion and spacing. - - Q 3. Underground tank a. Location b. Distance between tanks c. Di stance to property line d..: _D,phofYe e. Vent piping, .. swing joints, fill piping-, discharge piping f. Anchoring g. Hydrostatic test h. Separate Fire Dept. approved plans 5. Fire alarm a. Acceptance test b. Fire Dept. approved plans [r 6. Hood and duct inspections a. Installation b. Trip test Checklist prepared by (staff): [� 7. Spray Booth a. Location b. Fire protection c. Ventilation d. Permit [� 8. Flammable liquid room a. Location b. Fire protection c. Permit Q 9- Rack storage a. Permit b. Mechanical smoke removal c. Rack sprinklers d.- -Aisle width - [.%f 10. Fire doors and fire dampers -. as Installation b. Drop testing [ 11. Fire final a. Fire Dept. access Fi9S LEES b. Bldg. egress and occupancy load c. Hydrants d. Bldg. address e. Fire protection systems (1) Halon systems (2) Standpipes (3) Hose Stations (4) Fire Doors (5) Fire Dampers (6) Fire Extinguishers 12. Other a. b. c. d. e. f. 9. Date // - io -/� City of TuKwila FIRE DEPARTMENT 444 Andover Park East Tukwila. Washington 98188 -7681 (206) 575-4404 • PRE — APPLICATION CHECKLIST FIRE DEPARTMENT (construction) FOR STAFF USE ONLY Pre -app File # PRE- APP - 027 -88 Meeting Date 11 -10 -88 Occupancy Group R -1 Time 2:30 pm Project Name: Rainier Ridge Site Address: NW Corner Southcenter Parkway/ S 178th St CONTRUCTION INFORMATION [f 1. The City of Tukwila has adopted the 1985 Uniform Fire Code. This and other nationally recognized standards will be used during construction and operation of this project. (TMC 16.16.120) [` 2. Fire hydrants will be required. (City Ord. #729) 121 3. Required fire hydrants shall be approved for location by the Fire Department, approved for purity by the Water Department, and fully in service prior to start of construction. A fire hydrant must be no further than 150 feet from a struc- ture; and no portion of a structure to be over 300 feet from fire hydrant. (UFC 10.301 and City Ord. #729) [g 4. Automatic fire sprinklers are required for this project. Sprinkler systems to comply with N.F.P.A. #13. Sprinkler plans shall be submitted to Washington State Surveying and Rating Bureau, Factory Mutual or Industrial Risk Insurers for appro- val prior to being submitted to Tukwila Fire Marshal for approval. Submit three (3) sets of sprinkler drawings. This includes one for our file, one for company file, and one for the job site. (City Ord. #1141) /6yosr..RCs, ) [J1 5. Maximum grade is 15% for all projects. 021 6. Hose stations are required. (City Ord. #1141) [A 7. A fire alarm system is required for this project. (City Ord. #1327) Plans shall be submitted to the Tukwila Fire Marshal for approval, prior to commencing any alarm system work. Submit three (3) sets of complete drawings. This includes one for our file, one for company file, and one for the job site. [ 8. Special installations of fixed extinguisher systems, fire alarm systems, dust collectors, fuel storage, etc. require separate plans and permits. Plans to be submitted- to the Fire Marshal prior to start of installation. (UFC 10.301) Ri 9. Portable fire extinguishers will be required in finished buildings per N.F.P.A. #10. (Minimum rating 2A, 10 BC) Q 10. Buildings utilizing storage of high cal smoke removal per [A 11. During construction, an all- weather the building. (UFC 10.301) piled combustible stock will require mechani- Section 81 of the 1985 UFC. access will be required to within 150 feet of [� 12. No building will be occupied, by people or merchandise, prior to approval and inspection by Fire and Building Departments. 13. Adequate addressing is required. Number size will be determined by setback of building from roadway. Four inch numbers are minimum. Numbers will be in color which contrasts to background. (UFC 10.208) RI 14. Designated fire lanes may be required for fire and emergency access. This requirement may be established at the time of occupancy and /or after the facility is in operation. (UFC 10.207 as amended) [I 15. Special Fire Department permits are required for such things as: storage of compressed gas, cryogens, dry cleaning plans, repair garages, places of assembly, storage of hazardous materials, flammable or combustible liquids or solids, LPG, welding and cutting operations, spray painting, etc. (UFC 4.101) Q 16. Miscellaneous requirements 1) 609- ,nklet syskr. -e be. moa lore.e 4y Cf1'T. s /** W/uot02 6/L. e./A4A/ 541704 ..2) Ouaarrt_ 0461"t ii't-�ow 1r 5,,i# 4t 5/4Z*rs tnd reia',YR Aose sfreAms- , /dia4/+5 in flit e•alyttg .iv,i/ f //w ai sis llw.4.x. 3 510,),' h 4z o,n, 5-5 / w6 lull / tic. a✓ /au•ec2 Li) F, Lc- R- /.R,r► S y s "es.? 464- ,noe•k.E0 6y .c G t, , T4k, .- 4WMrsAt °C t(4 Cip..4a l si Leal e . OLadJ Checklist prepared by (staff): Date / /- /D -/00 • .• City of llikwila 6200 Southcenter Boulevard Tukwila. Washington 98188 Public Works Department 433 -1850 PRE - APPLICATION CHECKLIST PUBLIC WORKS (utilities) FOR STAFF USE ONLY Pre -app File # PRE- APP - 027 -88 Project Name: Rainier Ridge Meeting Date 11 -10 -88 Time 2:30 pm Site Address: NW Corner Southcenter Parkwa 5 1 /8th St CONSTRUCTION INFORMATION pl_1. Obtain the following permits: I Channelization /Striping /Signin �_ Curb Cut /Access /Sidewalk Excavation (public) kFire Loop /Hydrant (main to vault) Flood Zone Control Hauling (2,000 Bond, Cert. Ins.) - Landscape Irrigation Moving an Oversized Load 1,- - Sanitary Side Sewer 'd Sewer Main Extension (private) f-- Sewer Main Extension (public) Storm Drainage Water Main Extension (private) - Water Main Extension (public) Water Meter (exempt) - Water Meter (permanent) Water Meter (temporary) Other Q 2. Water and sewer assements may apply and will be determined during the utility plan review process. TAIL 3. Provide sidewalks per Ordinance #1158, #1217 and #1233, orb obtain waiver. 4. Provide traffic analysis for: /71 Q 5. Provide developers agreement for: R. 6. Provide Hydrological- Geotechnical analysis. 0 7. Review traffic study prepared by Q 8. Provide plan submittal per requirements on attached plan 'submittal handout. 0 9. LI /7r Q 10. Q 11. Q 12. Q 13. 14. Q 15. Q 16. Q 17. Q 18. Q 19. 20. Checklist prepared by (staff).: Date City of 4116ila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila. Washington 98188 (206) 433 -1849 • PRE- APPLICATION MEETING ATTENDANCE RECORD Pre -app File # PRE- APP - 027 -88 FOR STAFF USE ONLY Project Name: Rainier Ridge Meeting Date 11 -10 -88 Time 2:30 p.rn. Site Address: NW corner of Southcenter Py and S 178th St Checklist mailed to contact person (date): 11 -15 -88 Initials: BLD STAFF PRESENT ❑X Building (433 -1851) © Fire (575 -4404) [Planning (433 -1849) ®Public Works (433 -1850) ❑Parks & Rec. (433 -1847) Police (433 -1806) []Other ❑Other ( ) CHECKLIST NAMES /TITLES PROVIDED Duane Griffin, Bldg. Offi,Ci,al_; Becky Davis, Permits Nick Olivas, Fire Marshal El Vernon Umetsu, Associate Planner Ross Earnst, Public Works Director El Tom Kilberg, Crime Prevention El APPLICANT /REPRESENTATIVES PRESENT Contact Person: Name Bruce McCurdy Company /Title Southcenter Gateway Associates Inc. Address 1201 Western Ave. #410, Seattle, WA Zip 98101 Phone 622 -8443 Others Present: Name William Company /Title s 1008 Western Ave. #501, Seattle, WA Company /Title William Polk & Associates Address Zip 98104 Phone 622 -8443 Name Address Zip Phone Name Company /Title Address Zip Phone Name Company /Title Address Zip Phone Name Company /Title Address Zip Phone • a itac-(Weeatz9 ---foaJcicuic. pea< • ---112/Q V1(4 ov Untth-L t4-' Ass Eci4d4.4.t Tom / 17,/it OJvOA 2.p1at/t 77tZ 42 -ee. c/.4144Lz42.6 - 'C U4 W2 (1.1-bad, % .5-o_--e-e _45_ _ _ _ C a5a1., Al 0.24 aeD te.0,5 icfAxi,ct: - 6ba 6(./.<2.&e t 3a."11-€ ey. -e_me5 /Q53 Goy_ ypo6e.vb, - V- aze►iti Cece.w - wa,tG o)/ pa9 j_ G/ott()2il9,D — u/c�v (42 — _ jam rize,o. - �ti C°e2 - 0 L /aA o 66(/f lJ_.i G te,a, '8' Cod -L o% .��Cvzi v�L - rr7or7,/ -�9 - 2O. 6977/:-/C7)1,0.±' ed .a -/04 /CtL -d `11G A / ovv . n,ee. Iv a - 601)c1 _ Coy & - aovYJ w ac.cu 0-y+! Co-x,/e.%L'S ( ,u,(2 Crn- ,t2rG /'6x. Cao ca i-nuaLb2' CLm,.‘ %zr`v 4-eedif pazi----ra„oin,ntet,etee,. ,6y ergy ' v t'd a,& �4 �^ _ f.1 1r/ 170 e � J - _•_ -_. .- � /- Mize' g-e O x , _ cti� — rim. cz,`,e-- City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor MEMORANDUM TO: DRC FROM: Becky Davis DATE: November 7, 1988 SUBJECT: PRE- APP - 027 -88: Rainier Ridge Attached is the pre - application package for this project which is on the DRC agenda this week. As you may recall, an office building was proposed for this site back in 1985. The pre -app checklist and my notes are attached for your reference. Please do not give out my notes to anyone but staff. CITY OFTUK. A ioL ,/t -6r 1---a-1-04)0 Central Permit System PREAPPL1CAT1ON ADVISORY FORM NAME of INQUIRING PARTY W i UJ Can IGLU. a S5OCJIz e5 F R O P T V S I T E C R L O C A T I C N 5 /7 Q J t I _5 cun�er- Nieu,elg- THIS FORM HAS BEEN DEV1SED.TO HELP YOU BECOME FAMILIAR WITH THE CITY'S REQUIREMENTS AS THEY PERTAIN TO DEVELOPMENT OF YOUR PROJECT. A CHECK MARK IN THE BOX OPPOSITE ANY OF THE FOLLOWING ITEMS INDICATES THAT THE ITEM MAY BE REQUIRED IN ORDER TO PROCEED WITH THE PROJECT YOU DESCRIBE. - SECTION 1 -- LAND USE. OFILE SUBDIVISION /SHORT PLAT /BSIP /BLA (TMC TITLE 17) 0 CHANGE OF ZONING CLASSIFICATION OR COMP. PLAN DESIGNATION (TMC 18.80; 18.84) OBTAIN CONDITIONAL OR UNCLASSIFIED USE PERMIT (TMC 18.84; 18.88) COMPLY WITH LANDSCAPE SETBACK. HEIGHT, LOT SIZE, DENSITY AND PARKING REOUIREM T E ZONE (TMC 18.50 18.52 AND 18.56) e9.41:1 16p wV V 5'��� C voiatlij . 0 OBTAIN SHORELINE MANAGEMENT SUBSTANTIAL DEVELOPMENT PERMIT AND COMPLY WITH SHORELINE MASTER PLAN POLICIES (TMc 18.44) OBTAIN VARIANCE (TMC 18.72.020) -___I COMPLY WITH POLICIES OF THE COMPREHENSIVE LAND USE POLICY PLAN tN 5'('' SIAPGSa OBTAIN B.A.R OR INTERURBAN SPECIAL REVIEW DIWTRICT APPROVAL (TMC 18.60) i - FILE SEPA CHECKLIST AND FEE (ORDINANCE 1211 )-obS GQ,f" 01‘ j 'WPM. N�(S r' FILE APPROPRIATE APPLICATION FORMS AND FILING FEES (TMC 18.88) SECTION 2 -- INFRASTRUCTURE,. -a i .-_, PROVIDE EASEMENTS OR DEDICATION OF RIGHTS■OP ■WAY A. 58081588 "'r' .I( V1'54 fl FILE APPROPRIATE APPLICATVO1Ik:.PORMS"AND FEES $AUL& - 4.1?-181S PROVIDE SIDEWALKS PER ORDINANCE 1158, 1217 AND 1235 on OBTAIN WAIVER ROVIDE CURB, GUTTER, PAVEMENT, DRIVEWAY APRON AM REQUIRED: PROVIDE �yUU1 h TY C NTS AS REQUIRED: l WATER' Nam Bxvuisa EON WATER METER 6. DRA 1 NAGE OVILRg iNR olIA S ER MA I IN . EONS 1 oR SIDE SEWER 0 QIR�1NL 12AW I ON / srR 1 P I NQ / S 1014 1 NG 1N Pu■LIC R1 ^GNT.oP -WAY ..14041 VN � 91Ett4: CS M P' S • REP% 1 R UT 1 I. ITY COMPONENTS. AB RUGU I RED Cpl `4 . NOW 5. 1-krA c tu8 i s . ouu 4 cxo rnAs. iIt- r tT,Cf. NYV °NSW — �w► 244411 I t / i cQi COMPLY WITH meow*, WORM BU1LO1NO COOS 11182 EDITION (AS AMENDED TMC TITLE 16) PROVIDE ACCESS R)01 E12U4iMmieT POR, ACCOMODAT I ON OF HANDICAPPED PERSONS COMPLY WITH STATE ENERGY CODE{ OBTAIN PERMIT FOR HOUSE MOVING OBTAIN HAULING PERMIT OBTAIN DEMOLITION PERMIT OBTAIN SIGN PERMIT (TMC TITLE 18) 0 PLANNING COMMISSION ACTION REQUIRED 35.1 FAD) LIS rrL NIN ` V 4:143121154°) • F I LE APPROPR I ATE APPL I CATION PORES AND FEES MONICA 4 t S C vae►wt frASc)6 • $ kak ky.t ndcyu w QN P S CI trai YA ZZ al-Stre pnteilnles fitt - Illinc, Oae ►rr NIS13 c r- 04 04103 SIM QaCS (Nat. dt= MILMiOST iS . RsereAKAK C, 1?Al... PION 4 -- MISCELLANEOUS AND OUTSIDE AGENCIES OBTAIN STATE FLOOD CONTROL ZONE PERMIT (KING COUNTY SURFACE WATER MANAGEMENT) OBTAIN FLOOD CERTIFICATE, PEMA (ORDINANCE 1220, 1225) OBTAIN STATE ELECTRICAL PERMIT AND INSPECTIONS (DEPARTMENT OF LABOR AND INDUSTRIES) OBTAIN PLUMBING PERMIT AND INSPECTIONS (SEATTLE KING COUNTY HEALTH DEPARTMENT) , ry )c& OBTAIN CITY OF TUKWILA BUSINESS LICENSE (TMC T1TLE 5) u,� 1 CONTACTpTUUKKWIIL/A1PIME DEPARTMENT FOR APPLICABLE REQUIREMENTS !TM0^I A4V Ov vi ti? 1111P7 'Iklt —tc- a'UI. i• C:. i r. f .► .1.! a :• 0Mil'�Ti��'` FOREGOING ADVISORY CHECKLIST WAS PREPARED ON THE BASIS OF REGULATIONS IN EFFECT ON THIS DATE AND IS BASED ON THE INFORMATION WHICH YOU PROVIDED DURING THIS INTERVIEW. CHANGES IN THE CONCEPT OR SCALE OF YOUR PROJECT, AS WELL AS CHANGES IN THE VARIOUS REGULA- TIONS OR JURISDICTION OF OUTSIDE AGENCIES MAY AFFECT THE APPLICABILITY OF ANY OF THE FORE- GOING ITEMS. CHECK WITH CI _ TAFF TO OBTAIN THE LATEST INFORMATION ON APPLICABILITY OF SPECIFIC REQUIREMENTS �_P'. -E IN DOUBT AT ANY TIME AS TO YOUR PERMIT OBLIGATIONS. STAFF INTERVIEWER DATE I 6-86 6 STAFF I NTERV 1 EWER DATE 11 -4 -85 1 - • -1 INJO ,BIB. 0424 talcia&zietzseio sa s . • 7.1S 7s Dr CM”-t-rattoni p4eroa.6.44 • ciconge -ftve5u/Inalor pob-iliibo 0.14cAitt66 4p 470c1,44, ta,thc4ja-6 021, Plant-tint ptoct5. ti 1 ciAaiwiticklm7uc,,cat4ilaii5 #v ino.4444‘ _ too 1_ $1?)it' oulptectuf -yam, um -wiptu 4.1nataii, wattin_ciaLit5r. .40M- vittu lautA441..la1ut4 o 0.otricOom.ft 1t'I 6 124001Alt1i' . tap_ Jru IJt lelta._124011L1. vitw 105.5_ - adda,4,4) 04-4 Li/t/ cprojak ..14.1,411/110nrrIOW avita..) iscava./16 -Congraqg., - _ ADZJ46 loa,t14, ectiotalexd- aucvd Liav_ dhfruzp_mtitk -xotractiaiatv _ da,u775_1,dater mnont-114 Cloacred_fiitut _ cthininaritxu 1On taicth_ a. Ltalan_als ate41,160_41ot l.1/147) Cen*fiegs.fatt tn.) - A A Ott _Pan& bithC(.14q c-010LO4A4tii. 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Cand!'t'071 5_- er014' obierna. • • ! a Q i / /-Co 77.5- Pi : 147.a, etiz4, rLe l ) wit/Jae/14 !_ L_o FYQexu._ - 8ru - ock _, Gab CioAm.tazi, , .Pi'clG . feainatheiti [fir t56OGij yQ4,012cc t<c.i. 04.1 - _ . - am k..L.G14..44402,a ALA, t,tm_a i ,51otatd tubtokod l2i,w 94Lualg.t. /Stet dJ,i4 't - ok tope) 15' tomolJeapin auJl,►'. _ ►'cam?_l.' Compact .psi ex) Per Zone Cods _ ,5tcri'ts err 35 ' - y 51 fld, b019 . healuitioat__)is' 4410.t 5,‘e.6 OA, zone Code - act lvia ClOt4&4C11JC.. • eEScit,T 44/7y ion•, x.11 5eacis gto a m i wor rack ck raiNA L..7 g/`i,404.,c4/ . POL•K 4)H1L �l L L.4uern ?eter5ov• urHCel ler- C ?AT6 wAY AtEETiN6 • ///4/65--- gt 7 6c4r4c.4,0p, City o r ruu ,Q abikubz --FLeiNkr/46..N9r. Lo I t i PoLk /S C, The awitt?!e Cm's , veto r,_ 1ni t A4■A 111-iL ASSOC. c, r o f 7r4r -0,44 ; a /� c£ .. 4 -14 Tau) 'r 4_ Od, It et _4 t + - T? S -.- - /-R--" - _ _' -- mire* C P Ar• I Z (2-2(68 CA. scf�°A 1/778? ` frk c. (26 /90s, 1/(x/88 S : _' ! % -! i/17/8-e. +/-Z /8? " i 272i/dr. 5‘ze_ 0 4-407s? / Sc o fent G To pe-c„i K 4 7W8? 11‘, S -3 6-7-c l (l 8? �4 -fie e�G o,e- 3/28/€4r - -�� "lc/'P -e �.�. 678* sc_c_"_4_:; of- /2�8? v //a/tsc?? 7/74 e . -K&1 -7/z7/82 gii7(6? �(S &/S - CA1/23 ts- „e (cir/z7 / ?) L - - - (7ce, c7 4L 4 i az-ert,_, • Scmi<'-e- It 4/0 p_,;,e ate- ) cee".(;#4.42,. (06 �� .�- �:.� ,, - «7(178 ? 6) IFB? ,. ors S -- ;:ot_ c-4. _ 2Jt 2.ko _ AeL:44._= y1F-cee - r'-e; - , M Au-e-Or&7- /5770 7" -A4A-c Cam- GGam) 4AJ- F7k /C,�.e-pA, s ‘6_7/ _ 77s- • .A v PG-e‘ • cx,71 s-g-704) S---f- 1068 64,.v6c, '1-71078 ?; 4 te_c_ AL-R,:z-ca 2-72,2-7c58 145_ /4/_(__(,,, • • • • /nL OcJ Ct _ o - "DeVo"rV c-c, Gar- t.1"- 1_rreS) M-C- -- O 2 fit-, /cr i- - - -- - 4,yro -4A,j -�- - tc.,x0-c„e0e. 27/3, .4te 0 c_S.e /69 c . = (Sac/cc-779/8.Y kts-r b Li(- -f _ _A -Lc-- - -PI CK -uP Fore_ ?osr VPFiGC). 6/7' t is mw • 1.5 P /o/z6(_M_ /<;7444 aZOI ` = /80 ceos- v cu.2J 1047(?0 Cet,e)acte 4?,:et" r CE Y2_a la 63 v - RAINIER RIDGE SOUTHCENTER GATEWAY ASSOCIATES CONSTRUCT LUXURY APARTMENT UNITS 5. 178T" & I -5 EPIC 33 -88 City of Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 FAX TRANSMISSION DATE /TIME• MONDAY -- APRIL 10, 1989 10:15 AM TO: LEGAL NOTICE DEPT VALLEY DAILY NEWS (Name) (Company Name) (FAX #) FROM: JOANNE JOHNSON - PLANNING DEPT FAX #: 433 -1833 PHONE NO. 433 -1849 SUBJECT: DETERMINATION OF SIGNIFICANCE AND REQUEST FOR COMMENTS ON SCOPE OF EIS PAGE(s): 1 (+ Cover Sheet) PLEASE PUBLISH. IN VALLEY DAILY NEWS ON WEDNESDAY, APRIL 12, 1989. WAC 197 -11 -970 DETERMINATION OF SIGNIFICANCE AND REQUEST FOR,COMMENTS ON,SCOPE OF EIS Description of Proposal CONSTRUCT 108 APARTMENT ON A 3.9 SITE. UNITS WILL BE CONSTRUCTED ON 60% SLOPES. Proponent SOUTHCENTER GATEWAY ASSOCIATES Location of Proposal, including street address, if any NORTHEAST CORNER OF THE 178TH STREET OVERCROSSING OF I -5 IN THE NW ;; SEC 35; TWN 23; RANGE 4 Lead Agency: City of Tukwila File No. EPIC -33 -88 EIS Required. The lead agency has determined this proposal is likely to have a significant adverse impact on the environment. An environmental impact statement (EIS) is required under RCW 43.21C.030(2)(c) and will be prepared. An environmental checklist or other materials indicating likely environmental impacts can be reviewed at our offices. The lead agency has identified the following areas for discussion.in the EIS: EARTH, WATER, TRANSPORTATION. Scoping. Agencies, affected tribes, and members of the public are invited to comment on the scope of the EIS. You may comment on alternatives, mitigation measures, pro- bable significant adverse impacts, and licenses or other approvals that may be required. The method and deadline for giving us your comments is: ALL COMMENTS SHALL BE IN WRITING TO THE TUKWILA PLANNING DEPARTMENT AND RECEIVED OR POST- MARKED BY MAY 1, 1989. Responsible Official Rick Beeler Position /Title Planning Director Address _ 6200 Southcenter Boulevard Tukwil Phone 433 -1845 Date %� v O Signature / _ •���_ You ma appeal this determination to the City Clerk at City Hall, 6200 Southcenter Boulevard, Tukwila, WA 98188 no later than 10 days from the above date by written appeal stating the basis of 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 Planning Department. TO: Cit Y %f Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 ENVIRONMENTAL REVIEW SECTION CENTRAL OPEKAIIONS PROIbKAM DEPARTMENT OF ECOLOGY CAMPUS MAIL 51UP PV -11 OLYMPIA, WA 98504 -8711 FROM: CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT DATE: 4 -10 -89 PROJ /PERMIT NO: EPIC -33 -88 SUBJECT: DS AND REQUEST FOR SCOPE OF EIS FOR: SOUTHCENTER GATEWAY ASSOC RAINIER RIDGE WE ARE SENDING YOU THE FOLLOWING: Q Attached Q Under separate cover COPIES DESCRIPTION THESE ARE TRANSMITTED /RETURNED: 1 DETERMIIVAT•ION OF SIGNIFICANCE & REQUEST Q For your approval FOR COMMENTS ON SCOPE OF EIS Q For review and comment 1 LETTER - RZA DATED MARCH 23, 1989( For your use and information INCLUDING GEOTECH REPORT - RAINIER RIDGE AP,N�TS Li For corrections /revisions 1 ENVIRONMENTAL CHECKLIST 0 As requested 1 LETTER - TRITEC ASSOCIATES DATED 4/3/89 0 Other: INCLUDING ADDITIONAL DESIGN AND STRUCTURAL INFO. COMMENTS: IF YOU DESIRE FURTHER INFORMATION OR HAVE ANY QUESTIONS, PLEASE CALL 433 -1949. JOANNVJOHNSON PLEASE: [l Resubmit for approval [I Return corrected prints (23 /P4.LTRANS) (LR 12/29/87) AFF•I DAV I T OF D I STR•BUT ION I, Wendy Bull hereby declare that: Q Notice of Public Hearing L=I Notice of Public Meeting Ej Board of Adjustment Agenda Packet Q Board of Appeals Agenda Packet Planning Commission Agenda Packet El Short Subdivision Agenda Packet Q Determination of Nonsignificance El Mitigated Determination of Non - significance El Determination of Significance and Scoping Notice • Notice of Action Q Official Notice Q Notice of Application for E] Other Shoreline Management Permit Q Shoreline Management Permit E] Other was mailed to each of the following addresses on April 10, 1989 SEE ATTACHED: (Rauyit.244()) Name of Project Southcenter Gateway Associates (/( S S i gnatulle File Number EPIC -33 -88 Carol J. Lawrence 52 Puget Dr. Steilacoom, WA' 98388 Carol ,Lawrence 52 Puge 'Dr. Steilaco m, WA 98388 • • Carol • Law -ence Carol . Lawrence 52 Puge i . 52 Puge r. Steilaco• WA 98388 Steila , WA 98388 D. L. Gex otti 52 Pug Dr. Steilco , WA 98388 D. L. Genotti 52 Puget Dr. Steilacoom, WA 98388 Mario A. Segale Mario . iegale Mario •. Segale 18010 Southcenter Pkwy. 18010 uthcenter Pkwy. 18010 thcenter Pkwy. Seattle, WA 93188 Seatt e, A 98188 Seatt e, A 98188 Mario gale 18010'S thcenter Pkwy. Seattl , 1411k 98188 William M. Starr 17815 54th P1. S. Seattle, WA 98188 Willi . Starr 17815 th Pl. S. Seatt e, WA 98188 D. L. e otti 52 Pug Dr. Steil co , WA 98388 William M. -Starr 17815 54 P1. S. Seattlef 98188 D. L. G otti 52 Pug Dr. Steil c m, WA 98388 Willis M /Starr 17815 5 Pl. S. Seatt , W 98188 David Parrot David P rot Davi P of 5425 S. 173th St. j 5425 S 178th St. 5425 S 178th St. Seattle, WA 98188 i Seat e, WA 98188 Seat e, WA 98188 David a of 5425 S. 178th St. Seatt , WA 98188 Schneider Homes Inc. 6510 Southcenter Blvd. Suite 1 Seattle, WA 98188 Schneide Ho .•s Inc. Schnei 6510 South -nter Blvd. 6510 So Suite 1 Suite Seattle, A 98188 Seatt Schniede Hopres Inc. 6510 Sou t enter Blvd. Suite 1 Seattle,/ WA '98188 es Inc. center Blvd. 98188 Carol J. Lawrence 52 Puget Dr. Steilacoom, WA 98388 Carol Lawrence 52 Puge Dr. Steilaco m, WA 98388 Mario A. Segale 18010 Southcenter Pkwy. Seattle, WA 93188 Mario gale 18010'S thcenter Pkwy. Seattl , Wik 98188 William M. Starr 17815 54th Pl. S. Seattle, WA 98188 Willi 17815 Seatt Starr th P1. S. WA 98188 David Parrot 5425 S. 173th St. Seattle, WA 98188 David a of 5425 S. 178th St. Seatt WA 98188 Schneider Homes Inc. 6510 Southcenter Blvd. Suite 1 Seattle, WA 98188 Carol . . 52 Puge Steilaco Lawrence WA 98388 D. L. Ge •tti 52 Puge Dr. Steil aco.• , WA 98388 Mario 18010 Seatt egale uthcenter Pkwy. A 98188 D. L. e otti 52 Pug Dr. Steil co , WA 98388 William M. Starr 17815 54 P1. S. Seattle 98188 David P rot 5425 S 178th St. Seat e, WA 98188 Schneide Ho s Inc. 6510 South -nter Blvd. Suite 1 Seattle, A 98188 Schniede • Ho es Inc. 6510 Sou t •enter Blvd. Suite 1 Seattle, WA 98188 Carol 52 Puge Steila L. w'rence r. , WA 98388 D. L. Genotti 52 Puget Dr. Steilacoom, WA 98388 Mario 18010 Seatt ' Segale thcenter Pkwy. A 98188 D. L. G otti 52 Pug Dr. Steil c m, WA 9.8388 Willia M Starr 17815 P1. S. Seatt '-, W 98188 Davi 5425 Seat of 178th St. WA 98188 Schnei 6510 So Suite S Matt es Inc. center Blvd. 98188 Appendix D SEPA CHECKLIST (TRANSPORTATION) BACKGROUND: This additional SEPA checklist information was prepared by Gibson Traffic Consultants (GTC) as a supplement to the original traffic analysis /report for the subject site (Southcenter Gateway Office Building; by Centrac Associates, July 1986) and a follow -up technical memorandum to King County (July 31, 1987 to Chuck Shields; by GTC). Note: Proposed mitigation improvements at off -site intersections (King County jurisdiction) are preliminary recommendations only; specific improvements the developer's mitigation responsibilities need to coordinated with King County. 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. Site access for vehicular traffic would be provided exclusively via South 178th Street. The main entrance would be located approximately 3000 feet east of the 1-5 overcrossing structure. An emergency vehicle entrance would be located approximately 800 feet from the I -5 structure. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No bus routes are presently provided on S. 178th Street, due to the very steep profile grade (21 %) just east of the Southcenter Pkwy. intersection. Metro Transit has three (3) bus routes which serve the Tukwila CID -- Routes 150, 155 and 340 along Southcenter Pkwy. and S. 180th Street, which provide hourly service connecting Auburn /Kent, Renton and the Eastside with Southcenter. The closest transit stop is on Southcenter Pkwy., approximately 900 feet east of the project site. c. How many parking °paces would the completed project have? How many would the project eliminate? The proposed 108 -unit apartment development would provide two (2) parking stalls per unit, or a total of 216 parking spaces. No existing on -site parking spaces would be eliminated by the proposal. Note: At present, on- street parking is not permitted on S. 178th Street. and 'SN00 0ldddal NOSSI9 BLOT 68. £0 add l 'Z d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). In order to provide safe ingress and egress by site vehicles, S. 178th Street would be widened on the north side to provide a third lane for left -turn maneuvers (see Figure 3 of Centrac's July 1986 traffic report for Southcenter Gateway Office project). The left -turn channelization would provide a safe refuge area for inbound /outbound left vehicles at the main entrance, as well as mitigate the sight visibility problem to the west for exiting motorists (400 feet measured to horizontal curve on 1-5 overpass vs. 620 feet desirable per AASHTO standards for 35 mph design speed). e. Will the project use (or occur in the immediate vicinity of) water, rail or air transportation? If so, generally describe. The Green River is the closest navigable body of water. The nearest railroad lines are east of Interurban Avenue adjacent to Longacres racetrack, except for railroad spur lines to commercial /industrial facilities in the Tukwila CID. Sea -Tac International Airport is located approximately two (2) miles west of the project site. The subject project will not use any water, rail or air transportation. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Rainier Ridge Apartments would generate an estimated 660 daily and 55 PM peak -hour vehicular trips on an average weekday (per ITE Trip Generation manual, Section 220, Sept. 1987 edition). The prior proposal for the subject site (80,000 SF office building) would have generated 1,420 daily and 225 peak -hour trips. The present multi - family residential development would generate only 46 96 and 24 9b of daily and PM peak trips, respectively. Thus, the proposed project would have significantly less traffic impacts than the prior site development proposal. The peak hours for site traffic would occur between 6:30 -8:30 in the morning and 4 :00 -6:00 in the evening. e6rad pepuevx3 4 'L • • g. Proposed measures to reduce or control transportation impacts, if any: o When S. 178th Street is closed due to hazardous driving conditions (snow, ice, etc.) on the steep 21 % grade east of the project site, all site traffic would enter /exit from the west via S. 176th Street and Military Road S. o Provide a new concrete sidewalk (8') on the north side of S. 178th Street along site frontage, to provide safe travel far pedestrian /foot traffic and transit patrons destined for bus stops on Southcenter Pkwy. o S. 188th Street ® Military Road: Provide an additional southbound approach lane to accommodate the heavy left -turn movement and improve the PM peak LOS to an acceptable level. Note: The developer should pay his "fair share" of construction costs, based on the percentage of site traffic entering this intersection during the critical PM peak hour. o S. 176th Street ® Military Road: Separate eastbound and westbound signal phaaes at this location for safety reasons.. Note: The developer should pay his "fair share" of construction costs, based on the percentage of site traffic entering this intersection during the critical PM peak hour. o S. 178th /180th Street Q SC Pkwy. /57th Avenue: Reconstruct and restripe of the eastbound approach to provide two (2) left -turn lanes and a thru /right lane to improve the peak -hour operations and LOS. Note: The developer should pay his "fair share" of construction costs, based an the percentage of site traffic entering this intersection during the critical PM peak hour. e6ed pepue4xa R 0 R T FOSSATTI A S S O C I A T E S (2 NSULTING ENGINI2 E RS April 3, 1989 A PROFESSIONAL 2411) FIRST INTERSTATE CENTER TELEPHONE: SERVICES 999 THIRD AVENUE (206)621 -1803 CORPORATION SEATTLE. WASHINGTON 98104 SUBJECT: Proposed Rainier Ridge Apartments South 178th and Interstate 5 Tukwila, WA DESCRIPTION OF FOUNDATIONS AND FIRST FLOOR FRAMING FOR BUILDINGS A, B AND C This report is intended as a structural narrative describing the structural . aspects of the foundations and first floor framing for buildings. A, B and .0 of the above referenced Rainier Ridge apartment project. These three buildings occur on the east side of the project site and extend over the hillside embankment such that special columns, piling and bracing are required to achieve structural stability and to insure that the entire structure is supported on sound subsurface soils which will eliminate the . possibility of future building movement due to the sloughing and consolidation of unstable soils. Foundation design has been based strictly on the recommendations contained in the Geotechnical Report Submittal prepared by Rittenhouse /Zeman and.. Associates, Inc., geotechnical and environmental consultants which is dated. March 23, 1989 and includes previous recommendations, reports and addendum. dated December 21, 1988, March 20, 1989 and March 22, 1989. As recommended in the geotechnical report, concrete augercast piling have . been provided at key locations under the building, as it projects out over the hillside. These augercast concrete piling terminate at the ground.. surface in a cast in place concrete pile cap. The pile caps atop the augercast piling then serve as a footing for steel columns which are bolted . to the pile caps and extend up to the first floor level of the structure.. These steel columns in turn support a grid of glu -lam beams which carry sawn timber joists at the first floor level plus the entire superstructure of the building above. Pile and column locations are as indicated on the attached typical foundation and first floor framing plan. Also indicated on the enclosed plan (and building section) are the foundations at the west end of Buildings A, B and C which consist of normal grade walls and concrete strip footings which are carried to and founded on competent, stable bearing soils. First floor structure at the west end of the buildings between the concrete grade walls can be either normal concrete slab on grade construction (placed on compacted backfill) or sawn timber joists over a vented crawl space depending on existing grade conditions at the various buildings and construction economies. • • Lateral force resistance .(wind and earthquake forces) in the north /south direction is provided by steel cross bracing between the steel columns at the eastern most line of columns and piles plus the concrete grade walls and footings at the west end of the buildings. Superstructure shear walls deliver the lateral loads to the first floor level at which point the first floor diaphragm and glu -lam grid system distributes these loads to the braced columns on the east side and the concrete foundations on the west side. Ultimate foundation resistance to north /south lateral loads is provided on the east side by the lateral load capacity of the augercast piles and pile caps and on the west side by the friction forces developed between the concrete foundations and the supporting soils. Lateral loadings in the east /west direction are delivered to the first floor level by superstructure shear walls and thence to the concrete grade walls and soils supported foundations at the west side of the buildings through the connection of glu -lam beams and diaphragm to the concrete. The entire east /west lateral force is resisted by the friction forces developed between the concrete structure and the supporting soil. Providing 100% east /west lateral resistance as described above eliminates the need for augercast piling to resist loads in an east /west direction which is the weakest direction for pile resistance, especially if the load is applied from west to east. RJF /j WirWashington State Department of Transportation District 1 15325 S.E. 30th Place Bellevue, Washington 98007 April 3, 1989 Mr. William B. Betlach Tritec Associates, Inc. P.O. Box 1914 Tacoma, WA 98401 Duane Berentson Secretary of Transportation SR 5 MP 153.15 Vic. CS 1767 Status of Rainier Ridge Apartment Complex Dear Mr. Betlach: This letter is in response to your request for our comments on the subject development located in the northeast quadrant of the SR 5 /South 178th Street undercrossing. We received your letter and site plans on March 21, 1989. Your proposal involves a substantial amount of grading work within the limited access control zone of SR 5, and installing a closed drainage system from your site to an existing WSDOT facility. Your proposal has been sent out for review time, with all comments due back on April time, we should be able to provide you comments and recommendations regarding your and comment at this 18, 1989. At that with some specific proposal. A meeting has been tentatively scheduled for Thursday, April 6, 1989 at the WSDOT District 1 Headquarters in Bellevue. Should you have any questions, please feel free to contact Donald Hurter (562 -4274) or Phil Riggins (562 -4298) of my Developer section. PR:cmi 71 /PRWBB Sincerely, J i, S L. LUTZ, P: U lities /Developer Engineer TRITEC • ASSOCIATES INC. P.O. BOX 930 P.O. BOX 1914 SILVERDALE, WA 98383 TACOMA, WA 98401 (206) 692 -6400 (206) 572 -6400 • APR ° 3 1989 April 3, 1989 L. Rick Beeler, Planning Director City of Tukwila 6200 South Center Boulevard Tukwila, WA 98002 SUBJECT: RAINIER RIDGE ArARTMENTS - SEPA REVIEW Dear Mr. Beeler: The enclosed information incorporates additional design and structural information neccessary for the City to continue SETA review of the above referenced project. The package is bases on a draft SEPA checklist response from the City dated January 17, 1989, as well as communication to date with the City. This information is intended to provide your department with more complete, correct data with which to issue a formal determination under the SEPA process. Additionally at this time we request that this project be placed on the April 27 Planning Commission Agenda for consideration by the Board of Architectural Review. We appreciate the cooperation the City has shown on working through this project and coming up with a viable, buildable solution. We look forward to • continuing work with you and your department on this project. Please give me a call at the above number should you have any questions or require additional information. Sincerely, Wil a B. Betiach Pr • ject Manager Enclosures Appendix A: Appendix 8: Appendix C: Appendix D: Appendix E: Appendix F: Site Plan /Building Elevations Structural Drawings Landscape Plan /Typical Crossections Traffic Study Noise Study Water Availability Certificate his certificate provides the 'Department of Health and Building & Land Development with information necessary to evaluate development proposals. Please return BUILDING : • ND DEVELOPMENT 450 Ad nistration Building Seat , Washington 98104 2. .•344.7900 CERTIFICATE OF WATER AVAILABILITY Do not write in this box number name Ef/Building Permit ❑ Short Subdivision ❑ Preliminary Plat or PUD ❑ Rezone or other APPLICANT'S NAME Aj N I el e (, ?'' : PROPOSED USE !rt 11 Lfi pr'A-M al LOCATION 4o S I % C3 1 - 4-6- C S (Attach map & legal description if necessary) # # # # # # # # # # # # # # # WATER PURVEYOR INFORMATION 1. a. ❑ Water will be provided by service connection only to an existing water main feet from the site. size OR b. Er Water service will require an improvement to the water system,of: ❑ ) feet of water /main to reach the site; and /or (2) the construction of a distribution system on the site; and /or ❑ (3) other (describe) 2. a. ❑ The water system is in conformance with a County approved water comprehensive plan. OR b. U✓ The water. system improvement will require a water comprehensive plan amendment. 3. a. rites The proposed project is within the corporate limits of the district, or has been ET /The Boundary Review Board approval for extension of service outside the district or city, or is within the County approved service area of a private water purveyor. OR . b. ❑ Annexation or BRB approval will be necessary to provide service. 4. a. (Water ism will be available at the rate of flow and duration indicated below at LJ no less than 20 psi measured at the nearest fire hydrant 11>C7 feet from the building/ eperby (or as marked on the attached map): Rate of Flow Duration ❑ less than 500 gpm (approx. gpm) ❑ less than 1 hour ❑ 500 to 999 gpm ❑`1 hour to 2 hours ❑ 1000 gpm or more FOR ,�J 2 hours or more ❑ ,flow test of gpm ❑ other Q' calculation of. 2500 gpm (Commercial Building Permits require flow OR test or calculation) b. ❑ Water system is not capable of providing fire flow. COMMENTS /CONDITIONS 12l yrrtl4'i` iN 111/T7 l 6 C,V p3C f"AGILr17 C459V t 1.1.1 O /n( aet 4;:e4&44/6" (4z4,7etal pcnr4b ;A644,461". I hereby certify that the above water purveyor information is true. This certification shall be valid for one year from date of signature. KING COUNTY WATER DISTRICT #15 c '77R Agency Name Supervisor of Engineering & Admin. Title Jay E. Gibson Signatory Name 4alt.14 oat - Signature 3fz' /(1 Date 4 ▪ 1908 City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 • (206) 433 -1800 Gary 1. VanDusen, Mayor MEMORANDUM TO: Phil Fraser & Vernon Umetsu FROM: Ron Cameron, City Engineer,` DATE: March 28, 1989 SUBJECT: Geotechnical Scope for Rainier Ridge This memorandum contains elements of our March 27 discussion on a scope of work to evaluate the Rainier Ridge steep slope development. Other developments as well as Rainier Ridge were discussed in setting down the work elements. The purpose is to provide a scope of work that enables the City to make its development approval decision. The work will provide the professional engineering soils expertise of the steep hillside. It is similar to other previous development reviews such as the 1985 example. SCOPE Work Items PRODUCTS - evaluate the RZA geotechnical analysis - soils analysis - test pits and borings - research and relativity of other study findings - loading capability - site stability with proposed development - temporary construction period run -off control - permanent run -off control - affects of site plan on soils and run -off - upstream and downstream run -off - rockery and retaining wall design - construction period and continous monitoring programs. - site investigation evaluation - were there enough test borings for assuring non - failure of the development, other similar investigations - confidence level of non - geotechnical failure - construction "windows" (limitations) for weather - what monitoring programs are suggested /recommended - what maintenance (drainage facilities particularly) agreement is recommended Phil Fraser & Vernon Umetsu MEMORANDUM March 28, 1989 Page 2 - what drainage easements and agreements are suggested - is the geotechnical information sufficient to approve the development; if not, what else is needed - affects /considerations of upstream and downstream run -off These items are listed as decision factors for the site approval. We put it together as a generic scope and will need to have the consultant selectively evaluate that: G.re._;,4 would result in disapproval or mitfgations�or the development at are beyond our professional expertise and affect the development approval decision "What information is needed to decide that the development will not have a geotechnical failure affecting safet economics is the guiding philosophy. RC /kjr File: ASSOCIATES 'INC P.O. BOX 930 P.O. BOX 1914 SILVERDALE, WA 98383 TACOMA, WA 98401 (206) 692 -6400 (206) 572 -6400 • March 23, 1989 Vernon Umetsu City of Tukwila Planning Department 6200 S. Center Boulevard Tukwila, WA 98188 RE: Rainier Ridge - Soils Report Dear Vernon: Please find attached the complete, final soils report from Rittenhouse -Zeman & Associates on the above , referenced project. As previously discussed, we ,Z (i,-ys calOOTKALLIKA � respectively request at this time that review this data for completeness and accuracy. I have c1C,<.1)/C) enclosed the required $500.00 check to be placed in an escrow account for this purpose. If you have any questions please call me at the above number. Since ely, Wit : a B. Betlach Project Manager Attachment 39 4cc : o o o 3 86 90g Rrc- H= : 8488 C7,'2i(80 cc: Bruce McCurdy, Malibu Development Corporation Rick Lawrence, Holly Corporation • 4p04N LAMOIVUola. • January 6, 1989 Project RAINIER RIDGE APARTMENTS Subject: Design Review Application Checklist ITEM G - LOCATION AND SIZE OF PROPOSED UM= LINES AND A DESCRIP'ITON OF BY WHOM AND HOW WATER AND SEWER IS AVAILABLE. Location and size of proposed uthity lines are as shown on the plans included with the application for the above project. Description of by whom and how water and sewer is available: Water: Water District # 75, P.O. Box 68100, King County, Washington 98168 - Contact Duane Husky at (206) 824 -0375. Sewer: City of ZVk wila, Department of Public Works, 6200 Southcenter Boulevard, 'Rik wila, Washington 98188; (206) 433 -1853 rainBAR ENGINEERS • SURVEYORS • PLANNERS P.O. BOX 906•SILVERDALE, WASHINGTON 98383.692 -6400 3472 N.W. LOWELL "OLD SILVERDALE" OF UNIT BED / SQUARE SUB - BLDG UNITS TYPE BATH FEET TOTAL TOTAL A 2 (2) 1A 1/1 726 1,452 4 (3) 2A 2/2 936 3,744 5,196 1st 5,196 2nd 5.196 3rd OCCUPANCY LOAD = 48 BLDG TOTAL 15,588 SF B 2 (2) 1A 1/1 726 1,452 4 (3) 2A 2/2 936 3,744 2 (3) 2B 2/2 1,027 2,054 7,250 1st 7,250 2nd 7.250 3rd OCCUPANCY LOAD = 66 BLDG TOTAL 21,750 C 3 (2) 1A 1/1 726 2,178 2 (3) 2A 2/2 936 1,872 1 (3) 2B 2/2 1,027 1,027 5,077 1st 5,077 2nd 5.077 3rd BLDG TOTAL 15,231 OCCUPANCY LOAD = 45 D 3 (2) 1B 1/1 577 1,731 1 (2) 1C 1/1 722 722 4 (3) 2A 2/2 936 3,744 6,197 1st 6,197 2nd 6,197 3rd BLDG TOTAL 18,591 OCCUPANCY LOAD = 60 4 (2) 1B 1/1 577 2,308 4 (3) 2A 2/2 936 3,744 6,052 1st 6,052 2nd 6,052 3rd BLDG TOTAL 18,156 OCCUPANCY LOAD = 6A. REC. BLDG OCCUPANCY LOAD = 33 DOTAL SQUARE FEET BLDG TOTAL 1.911 91,227 SF December 27, 1988 Rick Beeler, Planning Director City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 430M p�go�Op4 Subject: Noise Study - Rainier Ridge Project The purpose of this letter is to clarify the scope of work required by the City for the above referenced project as outlined in the Pre- Application (File: PRE- APP--027 -88) meeting minutes dated November 10, 1988, and as discussed with Vernon Umetsu. Additionally, this study is intended to aMst in fulfilling requirements of the previously submitted Environmental Checklist. GOAL OF STUDY: To provide a noise study that will determine the suitability of the project for residential development according to federal, state and local standards, and which meets City of Tukwila requirements. SCOPE OF WORK: Measure level and hourly time dependence of traffic noise at the site. The monitoring will occur at the proposed location of the recreational facility, as well as various other strategic locations at the site in order to accurately understand noise levels throughout the site. Methodology will include setting up computerized noise monitoring system at site which would operate continuously for 24 hours during period of typical traffic flow. Additional short term (30 minutes) readings will occur with hand held meter at three or four other locations on the property to determine if there is a significant spatial dependence to the ambient noise level. Data collected will be analyzed and, if appropriate, certain mitigation requirements will be recommended. Lastly, as requested by the City, post construction monitoring will be performed at appropriate locations to determine actual affects of noise levels from adjacent roadways on the project. ENGINEERS • SURVEYORS • PLANNERS P.O. BOX 906 •SILVERDALE, WASHINGTON 98383.692 -6400 3472 N.W. LOWELL "OLD SILVERDALE" • PRODUCTS •ck Beeler December 27, 1988 Page 2 A report summarizing the methodology, findings, and recommended mitigation, if appropriate, will be submitted to the City for review. The report will include graphics which support the narrative such as computerized plots depicting noise contour information, and a site plan depicting monitoring locations and pertinent topographic features. If appropriate, sketches will included which show recom mended designs to achieve proper mitigation requirements I have attached a copy of the site plan for the project. The scope of the project is as proposed in the pre - application submittal The total number of units proposed is 108. The total height of the buildings varies, but can be determined by adding 30' (proposed top of building height) to the finish floor elevations as shown on the attached site plan. I respectively request that you review the above proposed scope of work at your earliest convenience. I can be contacted at the above number should you have any questions. I am looking forward to working with you on this project. B. Betlach oject Manager attachment cc: Jerry Flansburg, Holly Homes Cynthia Lohman, Polk Associates Vernon Umetsu, City of Tukwila ENVIRONMENTAL CHECKLIST A. BACKGROUND Conti' Epic File No. 33-88 Fee $100.00 Receipt No. 700(./ 1. Name of proposed project, if applicable: Rainier Ridge 2. Name of applicant: Southcenter Gateway Associates / Bruce McCurdy 3. Address and phone number of applicant and contact person: 1201 Western Ave., Suite 410, Seattle, WA 981011 0206) 622 -8443; Bill Polk, Principal. 4. Date checklist prepared: December 8th, 1988 5. Agency requesting Checklist: City of Tukwila 6. Proposed timing or schedule (including phasing, if applicable): Submission to Board of Architectural Review - December Agenda; Application for building permit - December; break ground upon issuance of building permit; foundation excavation and construction March /April (weather permitting); framing to commence - April /May; full completion - December, 1989. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. no 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. traffic studies Gnil stjirli:s hazardous wast investigation visual impact study noise abatement studies 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. no r.� • • 10. List any government approvals or permits that will be needed for your proposal. Architectural Approval (B.A.R.) _ Fire & Life Safety Building Permit & Associated Restrictions 11. Give brief, complete description of your proposal, including the proposed use and the size of the project and site. There are several questions later in thi . checklist that ask you to describe certain aspects of your proposal. You do no . 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. Our proposal is to build 108 high quality, luxury apartment units upon a 4 -1/2 acre site within a 7 acre parcel, utilizing the remaining property for nature trails oise abatement, and land - scaping. The project will include social amenities such as a social and meeting center. as well as recreational facilities including pool. spa, and workout areas. 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 applica- tions related to this checklist. See attached legal description, site map, and vird nity map 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? NO -3- C MIA? abolkf4c- e*4Ttisa + x146.19 Ih1rA4 L. G -2 Fesek47 aber6.1 —1 as ate- iiL�LzdL • 12 -A 14; why A� TC MA? • PARCEL 1: That portion of the Northwest 1/4 of the Northwest 1/4 of Section 35, Township 23 North, Range 4 East M.M., described •• follows: Beginning •t the Northeast corner of the Northwest 1/4 of the Northwest 1/4 of said Section 351 Thence South 01 49'41' West along the East line of the Northwest 1/4 of the Northwest 1/4 of said Section 35 • distance of 757.08 feet to the North margin of South 178th Street (P.J. Nusiol County Road): Thence North 65'22'03' West along said North Bergin a distance of 240.64 fest: Thence North 47'46'03' West •long said Worth margin • distance of 341.00 feet to t6p..Qast right -of -way line of Primary State Highway Mo. 1 (Junction S..S. N. No. SA to South 178th Street): Thence North 09' 32'33' East along said East right-lot-way line • distance of 240.39 feet: .?' 'Thence along • curve to the right, ,having • radius of 11,199.16 feet, an arc dfstence of 209.74 feet through • central angle of 01 04'23' to the North lino of the Northwest 1/4 of the Northwest 1/4 of said Section 3S: • Thence South 87'45.57. East along said North lino a distance of 419.14 feet to the trus.point of beginning: Situate in the City of Tukwila, County of Ring, State of Washington. ADDITION OF PARCEL WITH EASEMENT; That portion of the Northwest 1:4 of the Northwest 1/4 of Section 3S, Township 23 North, Range 4 east, Y.M., King County, Washington, described as follows: Beginning at the Northeast corner of said subdivision: Thence North 87' 45.57• West along the North line of said subdivision a distance of 419.14 feet to the East right of way line of the I -5 Freeway: Thence Southerly along said right of way line on a curve to the left having a radius of 11,199.26 feet, an arc distance of 209.74 feet, through is central angle of 01'04'23' to a point 260 feet East of Highway Station PC Lw 2,481 +29.2: • Thence continuing along said right of way line South 09'32'.73' West a distance of 240.39 feet to the True Point of Beginning: Thence continuing South 09'32'33" West a distance of 82.10 feeI4O a line 30 feet North of and parallel with the centerline of'!'he' South 178th Street Relocated Centerline, per State Highway Plan, sheet 42 of 133. State Highways Nos. 1 and 1 -L, South 184th Street to South 144th Street: Thence South 63'00.00' East along said parallel line a distance of 262 1B8 feet: Thence North 47 46'03' West a distance of 297.97 feet to the True Point of Beginning: EXCEPT any portion thereof lying within SO feet (measured perpendicular to) of the centerline of relocated South 178th Street as located and constructed by Washington State Department of Transportation. Contains an area of 6',050 Sq. Ft., or 0.139 Acres, N /L. • MA? Tt7 I �( MAP WEST VALLIY ?R.° J �� s -rE Southcenter TO SEATTLE TACOMA PARCEL 1: That portion of the Northwest 1/4 of the Northwest 1/4 of Section 35, Township 23 North, Range 4 East M.M., described as follows: Beginning st the Northeast corner of the Northwest 1/4 of the Northwest 1/4 of said Section 35: Thence South 01 49'41' West along the East line of the Northwest 1/4 of the Northwest 1/4 of said Section 35 • distance of 757.08 feet to the North margin of South 178th Street (P.J. Nusi•1 County Road); Thence North 65'22'03' west along said North margin • distance of 240.64 feet; Thence North 47'46'03' Nest along said North margin a distance of 341.00 feet to the..aastright -of -way line of Primary State Highway No..1 (Junction S.-S.. H. No. SA to South 178th Street); ThenceNorth 09' 32'33' East along said East right.. -jof -way line a distance of 240.39 feet; ?• 'Thence along a curve to the right, .having a .radius of 11,199.16 feet, an arc distance of 209.74 feet through • central angle of 01 04'23' to the North line of the Northwest 1/4 of the Northwest 1/4 of said Section 35: Thence South 87.45.57" East along said North line a distance of 419.14 feet to the true..point of beginning; Situate in the City of Tukwila, County of King, State of Washington. ADDITION OF PARCEL WITH EASEMENT; That portion of the Northwest 1/4 cf the Northwest 1/4 of Section 35, Township 23 North, Range 4 east, W.M., King County, Washingtcn, described as follows: Beginning at the Northeast corner of said subdivision; Thence North 87' 45'57" West along the North line of said subdivision a distance of 419.14 feet to the East right of way line of the I -5 Freeway; Thence Southerly along said right of way line on a curve to the left having a radius of 11,199.26 feet, an arc distance of 209.74 feet, through a central angle of 01'04'23" to a point 260 feet East of Highway Station PC Lw 2,481 +29.2; Thence continuing along said right of way line South 09'32'.33" West a distance of 240.39 feet to the True Point of Beginning; Thence continuing South 09'32'33" West a distance of 82.10 fee o a line 30 feet North of and parallel with the centerline of,lfte- South 178th Street Relocated Centerline, per State Highway Plan, sheet 42 of 133, State Highways Nos. 1 and 1 -L, South 184th Street to South 144th Street: Thence South 63'00.00" East along said parallel line a distance of 262188 feet: Thence North 47 46.03" West a distance of 297.97 feet to the True Point of Beginning; EXCEPT any portion thereof lying within 50 feet (measured perpendicular to) of the centerline of relocated South 178th Street as located and constructed by Washington State Department of Transportation. Contains an area of 6,050 Sq. Ft., or 0.139 Acres, M /L. Tb BE COMPLETED BY APPLICANT Evaluation for • • Agency Use Only B. ENVIRONMENTAL ELEMENTS 1. Earth - description of the site (circle one): Flat, hilly, steep slopes, mountainous, other Parcel has sloping terrain b. What is the steepest slope on the site (approximate percent slope)? 2 to 1 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. Soil tests have ascertained building site is comprised of glacial till - compressed sand and gravel, with excellent compaction capabilities_ d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Nn e. Describe the purpose, type, and approximate quanti- ties of any filling or grading proposed. Indicate source of fill. Minimum construction grading for driveways and walks, and select backfill for individual foundations. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Cnnstrurtion will necessitate clearing of only undargrnwth, weeds and hrush, and erosion will he very Glight; cgroindwater will he controlled and di rPr'i- d during use causing virtually no erosion. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? The total site is 7 acres of which approximately 4 -1/2 acres comprise the building site. Therefore,. only 65% of the parcel is included within the building site, of which 80% may be impervious, attributing to an actual covered surface of 51 %. -4- • • Evaluation for Agency Use Only h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: All cut and fill surfaces will be hydroseeded for soil stability and landscaping on slopes will incorporate soil stability measures. 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. Standard vehicular traffic during construction causing some dust which would be minimized by water application whenever a problem. 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: N/A 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, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. • •Evaluation for Agency Use Only 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. No 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. N/A 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quan- tities, if known. No 5) Does the proposal lie within a 100 -year floodplain? If so, note location on the site plan. No 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. Nn • b. Ground: . Evaluation for Agency Use Only 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quan- tities, if known. No groundwater will be withdrawn; nor . discharges to groundwater. except land - irri coati on. 2) Describe waste materials that will be discharged into the ground from septic tanks or other sour- ces, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. N/A c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so,. describe. This parcel is included in an existing lid that created a storm sewer system lust north of this property, flowing down to Southcenter Park- way and connecting with the Tukwila system. Site engineering will include drainage__ considerations and collection pointer, with storm sewer system deliypring water _ existing system. Evaluation for • Agency Use Only 2) Could waste - materials enter ground or surface waters? If so, generally describe. No d. Proposed measures to reduce or' control surface, ground, and runoff water impacts, if any: Site will hp PnginPPrP1 to gather SnrfaCe watpr,_,nd c9irPr,t runnff to r-nl 1 ectnr pni nts fors ±a m SPwPr. (SPQ l_C_ 1 _ ) 4. Plants a. Check or circle types of vegetation found on the site: x deciduous tree: alder, maple, aspen, other x evergreen tree: fir, cedar, pine, other x shrubs x grass pasture _ crop or grain wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other _ water plants: water lily, eelgrass, milfoil, other _ other types of vegetation b. What kind and amount of vegetation will be removed or altered? Vegetation removed will larg?ly be weeds,•arass, and brush, _later replaced with landscaping where go ssible.__ProjPc i- is designed with greellahalt_aumzinding building site c. List threatened or endangered species known to be on or near the site. None • •Evaluation for Agency Use Only d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: The landscape plan will include plants indigenous to the Northwest and the proposed nature trail /greenbelt which preserves the native vegetation, comprises approximately 35% of the parcel. 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: hawk, heron, eagle, songbirds other: mammals: deer, bear, elk, beaver, other: raccoons, squirrels fish: bass, salmon, trout, herring, shellfish, other: b. List any threatened or endangered species known to be on or near the site. c. Is the site part of a migration route? If so, explain. d. Proposed measures to preserve or enhance wildlife, if any: The greenbelt will allow any wild- life now on the property to continue their visitation or habitation. • •Evaluation for Agency Use Only 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solor) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Residential heating needs will be met_ with either gas or Pl _c ri _i ty, or a combin,ation of the twos_ That det- _rmi naj-ion will be made to construction. 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: The apartments will be con- structed as energy conservation units, utilizing double pane glass. insulated above all requirements, and featuring airtight construction. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. N/A 1) Describe special emergency services that might be required. Standard fire and health requirements. 2) Proposed measures to reduce or control environ- mental health hazards, if any: N/A • b. Noise 0 Evaluation for Agency Use Only 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? The two major sources of noise in the area are traffic on Interstate 5 and noise generated by traffic on 178th. 2) What types and levels of noise would be created by or associated with the project on a short - term or a long -term basis (for example: traf- fic, construction, operation, other)? Indicate what hours noise would come from the site. Short -term noise would be the standard construction sounds of hammer, saw, and machinery regulated by construction hours of 7a.m.- 5p.m.. Long -term would be residential vehicular traffic. 3) Proposed measures to reduce or control noise impacts, if any: Extra insulation within the units control interior noise and the greenbelt surrounding t$e_ project serves as both baffle and muffler. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site . e ently vacant- and largely —aurrounded hy vacant land. Several singleiamily residences are separated hy 178th. b. Has the site been used for agriculture? If so, describe. c. Describe any structures on the site. Nine • •Evaluation for Agency Use Only d. Will any structures be demolished? If so, what? Nn e. What is the current zoning classification of the site? PO — Professional Office f. What is the current comprehensive plan designation of the site? N/A If applicable, what is the current shoreline master program designation of the site? N/A g. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. No i. Approximately how many people would reside or work in the completed project? 250 residents • Approximately how many people would the completed project displace? None k. Proposed measures to avoid or reduce displacement impacts, if any: N/A 1. Proposed measures to ensure the proposal is com- patible with existing and projected land uses and plans, if any: Initial study was done to provide compliance with current zoning and compatibility with Tukwila's Comprehensive Plan. Luxury apartments were chosen over professional office because of softer neighborhood impact and greater emphasis on visual integration with site. • • Evaluation for Agency Use Only 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low - income housing? Proposed project consists of 108 units designed for the upper- middle_and high income brackets. b. Approximately how many units, if any, would be eli- minated? Indicate whether high, middle, or low - income housing. None c. Proposed measures to reduce or control _housing impacts, if any: The maior impacts of this_ project are posit ve by providing more units to professional peg• -. without eliminating existing units of an kind. Aesthe. ic' and raffir imparfs are discussed separately in following sections. 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? Proposed buildings are a maximum 45 feet in height. Exterior of buildings will be_ cedar si.ding� b. What views in the immediate vicinity would be altered or obstructed? The only possible obstr ac- tion would be a partial impact upon a single family residence located on be other side of Interstate -5. c. Proposed measures to reduce or control aesthetic impacts, if any: Landscaping and greenhel t as previously described, • 11. Light and Glare • Evaluation for Agency Use Only a. What type of light or glare will the proposal produce? What time of day would it mainly occur? ThP project would include low -glare site and building lights, turned on from dusk to dawn. b. Could light or glare from the finished project be a safety hazard or interfere with views? No c. What existing off -site sources of light or glare may affect your proposal? acne d. Proposed measures to reduce or control light and glare impacts, if any: Choice of low glare outdoor fixtures. 12. Recreation a. What designed and informal recreational oppor- tunities are in the immediate vicinity? Nothing exists in the immediate area. b. Would the proposed project displace any existing . recreational uses? If so, describe. No c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: Recreational opportunities will be created within the project by a nature trail and physical facilities, i.e., recreation building, pool, etc. -14- • 13. Historic and Cultural Preservation . Evaluation for Agency Use Only a. Are there any places or objects listed on, or pro- posed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. Nothing of known historical or cultural significance on this property or in imme- diate area. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. N/A c. Proposed measures to reduce or control impacts, if any: N/A 14. Transportation a. Identify public streets and highways serving the site, and describe proposed accss to the existing street system. Show on site plans, if any. South 178th b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Access to public transit would be 300 yards away at Southcenter Parkway. c. How many parking spaces would the completed project have? How many would the project eliminate? 220 • •Evaluation for Agency Use Only d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). The budget for this , roject includes the cost of widening 178th for the addition of a renter turn, arcelerai -ion lane. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. 400 trips a day with peak volumes between 6:30a.m. and 8:30 a.m. and 4:30 p.m. and 6:30 p.m. g. Proposed measures to reduce or control transpor- tation impacts, if any: The provision of a center turn lane will alleviate the primary impact: that of traffic entering and exiting 178th. 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. Th would be that of fire protection., hopefully never needed. Projects o£ this nature typi -. cally a tractprofessiorlals with few children and a low crime rate. b. Proposed measures to reduce or control direct impacts on public services, if any. prevention of fire is a_prime concern and fire codes, flame retardant materials, sprinkler systems, and designated fire stations will all be incorporated. • 16. Utilities • Evaluation for Agency Use Only a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other. All the above excepting a septic system, for which there is no need. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Electricity - Puget Power - Hookup only Water & Sewer - City of Tukwila - Hookup only Natural Gas - WA Natural Gas - Hookup only 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 made it decision Signature: Date Submitted: I2-lz2788 PLEASE CONTINUE TO THE NEXT PAGE. 'TO BE COMPLETED BY APPLIC• • Evaluation for Agency Use Only E. SUPPLEMENTAL SHEET FOR ALL PROJECT AND NON PROJECT PROPOSALS The objectives and the alternative means of reaching the objectives for a proposal will be helpful in reviewing the aforegoing items of the Environmental Checklist. This information provides a general overall perspective of the proposed action in the context of the environmental infor- mation provided and the submitted plans, documents, suppor- tive information, studies, etc. 1. What are the objective(s) of the proposal? _ To create an aesthetically pleasing, profitable utilization of this_property, which has long been held by developers of some of the earliest Southcenter area properties, while having a relatively low impact on community services, the environment, and adjacent property owners. 2. What are the alternative means of accomplishing these objectives? The only viable alternative is to build a much higher office building for the _government or largP corpnratinn, where one can ng fnntage to make the prnjer.t prof i tahl P for f i nanr-i ng to hp nhtai necl _ 3. Please compare the alternative means and indicate the preferred course of action: The proposed 108 unit apartment complex is Southcenter Gateway Associates' first choice because of aesthetic masons: secondly. the builder. Holly Corp.. is a quality conscious. retablearoup known for first rate projects. and also that the proposed project will provide more landscaping and much less continuous paving over the 4 -1/2 project. • • Evaluation for Agency Use Only 4. Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? Both the proposed project and the alternative are compatible with both the Tukwila Comprehensive Land Use Policy Plan and current zoning for the property. Proposed measures to avoid or reduce the conflict(s) are: N/A -23- 1 Sou -nosTE I � ' EL gq h I 03 1111.111AK r"" ozos.•• MICIITLIO117331 IrISV •noxenoz OTIMI 111151570 71/111:CMS. nte-r. 1,211,11irVIM 774 NIMATTLI I.,14,11Ms rttl, .1. +.0 is 11,10J1.11 •■•,,n1 SILVIDOSSV ,110d IAIVITIIM (2) "TeJlcIA-L '711VM 5 4,1,1f$V ,741 L / NW I /4, NW I /4, SECTION 35, TOWNSHIP 23 NORTH, RANGE 4 EAST, W.M. APPROVED /— 5 1Yl SLOPES [COSI..ro ScS+.cNr.rlw COO. 0.47E0 1. asst tat ,on and detentson ponds are to ER constructed Or plan p straw Oates shales. t rr [anat.,' tin,' such tore tnat the peraanent drachaqe ISSIIII1VS ere operetta:sal. a. Once drouno SIP °;pots n Pe constructed prior to any Std.Ynta<tantContdoll r;l.r� eroscon 7. Add, zonal started stras toles or other may Or reducred at various orner looalcons for emratedcuo.ol ouf1 ° con,trompn. Locate sc•aw Oates Palma or ootenttal Etc, !FIEFS 5^,1 see, cle redh,reent: SIII 5^les• prle•e t anrtc as NnJISSI [d 715 Or arson Coen al, tart ape Ills. or tl+al . as.—.her eanularturer. /j S ` . - �L - T /107 — — 257.0' ;//4( SILTS dL LT FENCE .420 BALE CIEOCS ASR C INTO oi_ , -_ TItt�N _ _ _ i ‘[.5,y S /LT FENCE NO SCALC ,Ell OMOOTMLIN SOWSS OW, am LieLNIlLJ E�ROOm�TTO / • _ � Y . . S ntur oEOO a L z ant Tt TK CONTOUR INTERVAL . 5' • • SCALE. f 40' TUKWILA, WASHINGTON RAINIER RIDGE • JOB NO. 708 SHEET C -2 OF 13 PLANT LIST - Trees 4,YANI74"... I-LAME Ast}113oL. 4,570-1.4 al sat.- rir,44740, A44 6 1,1-A1144o04-17 1-11,1441,Y 1-PPL-6 41 0 - 441...INTUVI v1142. N144..E. 5.1Rcal 41.• 0 i, 0 c-5/7..uVIR1Y1-1,-11,1 4Apq-{..4.1 1,5f,A41,, -Met F1.-.1.04-54a cEA6APPI-E. 1341'4.4 I. t4.4.4.1 1400.+ 1 • 115 11 FML.-1,1, "-- '47'-' 13/4.440. P'1757744 f,..4aa4.1,4 ,-441.1. b I 6 0-114,1Y.1PI114 517410044 44, 0- 2.4 - 1.o ... ST-1740. -APP244 .0.• -0.2'145 if. 4.410,4'1140- 7.$ 13 „ 0 ,141,11.0-4.,o,1400-11. L.0-,.1.1-1 011 1' ,..g.,..04-47 e-fPR0-47 LSI El +3 0 Pl741.44 1-114.41A, eI• 10' 4 f...,-0- 0045 5 1 5 0,-,V.-I-1 rit-If.. 01HLIS 411.,•..-ne......, 4) F5a.4.71,1-maa rart-tt-45511 a ; 5 14,, 1AA-161..As Fla- a 1 e. a.- 07' 4'06/-111,4-1 6 10 t4L+141. 0 10 .4001 I '0/4.4.0i• 6 441. 51 5 0 7071,00- YI10-i6e-T SIOH 1-1.61.1- ..f5e1 Hof 414040.0 --? _,..--411t40461, PISI041-66c, ,...-' --- 0410.5 AS 94.61....01.119 2 Int .erstat e5 PLANT LIST - Groundcover 60114719.07- cm-11-m-1 SizE 407441-10 1-1Y5P-IpW2 1441.11.1tt RE-764.14 P0,440.£ ,44716' F.644.....1.0o WHITS- 41647-HP1.- 1-1-014.9-1‘..14 9.70.0077157-4 ,-,..40,14.1.1.74- t • 1.1-.1.1.11 LA,,64-1PF-4,1- S'114S0. 7-07-000- 1.l_ 7-00-1149414.£ 4oe HYoP... 44E0 49,10-7') BLDG. '13" PLANT LIST - Shrubs 111,11441,04- HatAE WI" (..Mt.4./4-1 FLAME 41a- • _ • • 1-otx.o'sefio • 470A4974 &PAY, .... -- - • • : 7-1004"-44 079084 • 4*' - P7-EAST1.44 10701,0 14 ; 56115.741,4 12414. .A-1510Puorur6A. 961, versemy 51 • • 04.A.L-4.44414. 9440-9A : ROO 51.451-Lm-11A 04' 141140760 94M-1-1.S 40 ' H-cla9044460. 1.40-0APK0.41. • F.0-4-4-1 14.(XA14o04. 61- 1, %14.0 GRONA/A ) 7440O4942 14074.0" 01 1-1'6'="`Hr 1;r::,5Z14'.1 5.51. 2,11 5901. 5 1- -7-4- SI o.c-- 5111 M411o,410. Ax.iPO4,.11.11-1 011-451047 GaR.PC 4 ' .,-, 101 11.(9X-A,......A1-1RX14-11e..5 4' e 0.• 41 1,15f,45 1F070-50 PL02.16' , FLAME of 1146 F.r..E..-r 5 '..,..• *a - , 919445 M,71004045 ( ) 4770740 01470- VA ...• 'b-tr141 LN 1 LM .a 304 • 41 FI.945 LAO- 101-ro Lovieft...1. arro 1.-LrY149.4-1 L0.t040- 4 '0 .-- 5, i PR-L11,4-11, 1.-7441-704'IK1- FiDenumoi- l412.0-. '34,7.1t72,-,744145 V19.04-14L+1.1 497412411 p#wn VI5.4744,41."1 avEREST RH0451 . 14-51. FosE. 14141114E-? (MIX. MAY) '4.44947-4.144-1.5 14141-10 (1-1.1116., • APEA..) 5..1. T.., /4 0.7-17-0-9-' (9114- M41,-H) .111 APEiL) Z1'4. .I. 0 10'- 121 515 ▪ ie. Iv-1W el 5 ▪ 21. 41 6 • c. 151 i6" 0)7. I '01410P0SE0-1' ARP-PS P-S . TV.rall°0" c••■ 1:'..3"317 3. 14 Est RAINIER RIDGE a PLANTING PLAN GUAM:PALL NW 1/4, NW 1/4, SECTION 35, TOWNSHIP 23 NORTH, RANCE 4 EAST, W.M. ca 04 /WE / 'ZVCE ,, RIM ELEV. ••• 24 7.77 -- La - 244.-i7 15r9701-24.65 .1i. , - 1-r.0----.2"-,_W_ 7,7 -. 7---T---' - ---- --- ,- / C/ -_ .. _ _ .•X ii43-6--- . 2E/;0 / ----- - 2 ' ' . -SA /2■9#90 „' 7- / - - .Ss r- - (/ .7/ -?yi , , '`. t, ' /7— 44} (-_.- ...<2. "). / ". ---- - - --- - -- • ,, -_ --- ---- - "-------- " ..- 1 ..- --‘,__ 1-5 C8 033 TYPE I RIMLLEt 240.09 237.09 CB 1132 nWE 57484.80 ‘,0 lam 61.66 - 237.67 _ - 229.67 _-;1„...7.4,-,----...„—____- --- siarA427I 7',38.118 ,..1'--_-:__-- • •.1i13.11/75.' ' - --- 7-- -.. - -- riLi L-E.2-1 .2,23:- ,,..77:,: 'Ill ,111.:111117,;.fl' ‘1.1111/111'.!.1 ,I :1 :1'1 ):\ii../ .;1')L.i.I.,1/:(-,h .1:1P'; #C i, Type 2 T ;.,:.-fv :4:W \\.'•"'''P ' iv' 1` • •1' q///re 1 -V:....• , -r- 7 4R.L t F5 -. I: .52 1. . - .- 9- C9 AI P (il.,,11l, \1,/.1' 1\ 'c A. .;, k,\• \/01.' 7/Ii,./.F03 (.,,`,,... A __I7A-.R I . DEEN0 NI SEE 0E79111 Al7C — ); l, 0 T, ' ,■) fl„, .: '_ • _ - 1r;' 1 1 i,t/fI '1 - .29'I . i1,1i 2f ;/ ,:; 4,, L,..---F7-'15- CMP.-l1 Ii I .. ---_,- 4RE' __.__7j_____-i•_.,:.--,E'7V.7_ -:iI-..L---7-_-- -- __--_-_-- ,,y ,../Y b1..Pilp1:.'..ii!.. ::d 1 11 li'ii'iii i . i.lI- 1, I,:. , . . 2.ai=- ,, dmil :: = , V /11i ;. l ;;;,l,l„ i lil l ( s5::___ . . /.::,i if ,„771 / 1042RT --_so,„7 . ri ,.xr, .. .. ir._ _-_=----•..---v • -• 1?//,;;;1-‘14;1,'11•• 1 1,1 --E-0 ---.::--:---7 7=--..._,---,1,---'----- --:---- /./ aornaiinvearby4,,zr , 'T. 7i • ____ ,i 60' .ST74R.811ATE PPE ..........1; .., ....T.--1..-_-- .• .-: .z.:. ---- -7-:%,,.....; -, ,^"---. VP I .... :- -_ .... f--_ - . , -_-,----_----; ..:: --,---.,--- - : ----,-;'-'...-- ...„...;.....,__.---___:__;_---- - ____.--___.---„-:- __-----___---•--_,_ ------;•.„.---- .- _,--;-_,, :"."---...-.:""--2-'---7_-_-----..,--='-- --:-- '-,•-• .----_-__- -=:-- -;-----_,- ---;--_, - - .-, - - - - -, - - ___ __-___ ,---- -------- ---- - APPROVED ,STA-64-91.99 -/-- WA7E74 4'AL4f5- _ 4' • w STA 0.0000 , FIRE HYDRANT - WATER vALIE • 1,* • - - .11 , , . = • ;a.' , • /i* sir F.00I- AND \,„ STRAW Ire- / erfiCA S eEW - / I I WI • — _ - - ------ 1/ l/>14P I J 11-92 07 _ W W - • -r-ST* 170 LF 12- CAA 176-Wk 15C1LF- *VW - —. :AllrELAW.- 4_229.63 226.63 __STA,Sw8207 DATED 60" STIL PLATE PPE LE. • 772 BOST. WSOCIT EAERGY DASSPATOR 1 -- ---- t CONTOUR INTERVAL = 2' SCALE ••• 40' TUKWILA, WASHINGTON RAINIER RIDGE ROAD AND STORM PLAN JOB NO. 708 SHEET C - 3 OF /3 Az n. OVERPASS -\ 1� e GUARDRAIL 4 ' /... _ sS . WATER vAL L4L ' . +�6' _ ^B Lr 62-PV▪ C �r WATER VAR vr RRE HYDRANT / o �` / Jl♦ / F 4a g --70 LF 6''PVC 02X- t-=-224 z,v J- / mai �� FENCE - \ -/ / 1 NW I /4, NW 1/4, SECTION 35, TOWNSHIP 23 NORTH, RANGE 4 EAST, W.M. r . CO. 744.50 a' `61 / -5 ALA 14.3 -- i R /M�lEV= 23fi00 _ - -CE. IN -222L LErW = 221.77__STAr4.80 33� Aelf r • tic.0 /AI rE 228.65 U 52 LF 6' FVG mte 49 LF 6" PVC O24r29i 01235E j � -. • : LF 8' PVC O7.5X - NIERI 01LF- 44 =&fM - �__ STA 2.0 22'RT. „ ; 016.6T 52 LF-6N -PVC � /- — 4 LF PVC 3 , T r ▪ - m+aO6. f ii 198 LF 9 P`FC� I rl, -LF 6" PVC 02X u1- _ ieE� RIM - ELEV =7 I.E. IN I.E. OUT STA. 4.76 2O'RT. APPROVED DATED LLr, !VII'. SANITARY SEND CONSTNVUUSr NOTES I•I ALL INTER!ALS AND NDWNANSOP OWL( DE IN ACCORDANCE NfrS TNO \VIII REWOENENTS 'I rTE LATEST' E057555 5TH• A.P.r.A. LTD 5.50.0. r. T I .I•, •� I\' \ • St.M.ID SPECEfC DIE CI D O.E. ILA COAT liE CS! SEWER R PLAN I� I '� rwrC5P.L ('S7 5 !1 CI, OF T SrSEWER C.SENSTSEr5END EVEL AND N 1 1 rc cnr 5 rLxNlu aan roar a cSarNrrrw AND DEVELOPMENT M.N. 4'AI `I`,� %!V IIII 1. . 505511cr585555 Norm, 7e EroSNEEREA. T� EvEN! OF T 'I DISCO.55 5 505L5 s rofNG 2(51,0 PATER w DISCREPANCIES FRON RIM ELEV . 2.24Q� ll FLANS IN GEODES. LOCATIONS ANC 550 ExYsrrxc 55'Drr5 C0 rH- I.E. IAL = 21,L L7LS II, CONTRACTOR L VERIFY La.1roROAND ELEV. rrSV e` c5.c<rr56 N+rw TEA OU7 =; 211, k� I' a cALL S"roANfra. SANER NArr8 SMALL BE AIR TESTED APO T. 111 8 h 5b 1 1T ' fN P flEO SID S N NS NULL .." � ..". TESTED 5e 2 KR ro 1,IT LL Be �aE AFTER THE NE , EN RAC.FILLED ANT COMPACTED. ON RACT. AL,LWOW. ALL MATERIALS REWIRED ND Aro 2 LF 6 r FV� j�l��l�! \\ • TESTING 5wL 5 6P 05 55 06555557 5f5, O? / ) I�� /,,D MNCElNOlICE ORA RErrFoa flsr vEEnrwsfx�Nw 5 z, rows C.O. - 11.1 /,!/'.. WIRED Crew ID OBTAIN ALL - I:E.=214 00 ;j' q: /� 5E E555407 PER01'S LASCNENTSIL550RroLEaa ,571.5c r �TN'"'YETSOS.REClw _ ! SFwE T E Ixsr fa 5' 5 5ER c5w6crr / Lf EK • raso :�/ll / Crrr a'rS.IL�SP.Wrrtxr .. NDLrC NO.5 5NALL BE NOTIFIED - W . 2C5 5 1111 1, l// 7ro TEENS NRISR r5 .65 5 50 565 SHALT 5 505 LF 0Ur 2J180 iI /, 1111 PROPERTY OOrrER .nv IN ITS OPERA, ERE I. AACIP 5- rrE I I' 5 R5' 755ISW FLN O15 S+ Aro OFTSIrz IIA�� I ACCEPTED E 5A 755 , YE OF IL Sr5'EO TO CE CITY 5' r1ALNfL. IS _. w_. /�1 /I/ I ACCEPTED A.II• rN 2I r. 25.+crL .x ACCORDANCE NrrN INC DEVEL S`ER5 — IS/ONS T I I. B. .x. DEPART.N rO DE. C . . AN IBE REY . AND. ED ANDS ,R IKEC TI. IN OTltftlES ExS:nfERINO OIVI5f5r PRIM�IPO O 9.a Ir SIOlfS. IN !rt FILI D. NEE 5 9rE5 AEgi0vE0 ,ANC 55 D.rtDf SIl�NKKVER CIMTNC!lwvlSE IN UN TAW P0. CIE Or Of LOCATED LESS rm 00ILOf7GS5Al AtL 5NCS . t55 90' MOW 30 w AT LOO FEET n...srlp -. - -EXISTING RH RLN ELf v.. 2967 E.W. ff. OUT .I . S0 9E NE. CONTOUR INTERVAL = 2' SCALE 1' - 40' 2 U TUKWILA, WASHINGTON RAIN /ER RIDGE • SEWER PLAN Z 1m ❑A irsi Erg Wo °F� o S Wo2m F. a W �N JOB NO. 708 SHEET C -6 OF 13 OVERPASS GUARDRAIL 6-X6-X8" -r 4771 VALVES / COORDINATE DE -IN WITH WATER DISTRICT NO. 75 6-X6-X8- -r WITH VALVES COORDINATE 77E -IN IN IFI WATER DISTRICT NO. 75 WATER VALVE'S EO 1 FENCE NW 1/4, NW 7/4, SECTION 35, TOWNSHIP 23 NORTH, RANGE 4 EAST, W.M. APPROIEP /-5 Ai II I/46 BEND k2• Lf/ F C% PV P , ' 'V/ 5, A/ ? V/ / D.I. IANDARD HYDRANT ASSEMBLY VALVE FIRE N M `� WATER HYDRANT JOTEA SEVEN CO SDECTION .ores 6 TIE w! 662(6 u0 EMOS W COST9o1fON SHALL M.O. PIN 63 ST004O5 W 4126 COLN, LATER OISIRICT 675 COKNI EDITION Aw. STANDARDS. .PP. SNU. 11 •u0 Ix CONANCTION NM NNE cur E OPP . HOLIC BOWS NA. COSIRLCTION ALO WKLONENT STIM4OS. P. ERIALS FOR ICI NATO AWNS ARE AS Sow ON P. 0.AL6. PIPE Sow SULL E ABW C -SW. CLASS 450 .10 SOIL CDCOW 70 lNE IECUIREAENIS LISTED ABOVE. p ALL DUCTILE IRON PIPE Sow SOIL BE CLASS SO CENENI LINED PIPE NO SHALL 5. 262 TO IRE 9022LNIS LISTED ABM.. 5. LOG TOR NINE 9441 BE INSTALLED ALONG TIE fMfE IENSM W ALL NEB MANS AV Sm. E COMMIE° ELECTRICALLr TO A 11041 ON GON VAL VE .IO ST19W1. l0 OE Sur.. AT EAO1 FIE MAUI . 50.1DE5 Shut E NNW PM APPRO. COPECIO6. ARC 60fi4OR TIE SuIL BE IA GLEE OR LEER COWER. 6. L FIE NRYMNTS SLALL BE ONr WA. N2pwIS EE1IK N. C -502 .IO E P/IIN NPR 54 STOW CMCCIORS ON NE nw PORI, 7. TNE NUM. RAMO W CWVAIOE EON B• PVC IS 490 FEET, FOR B• PK NE IONIAN RAO. IS ISO FEET. B. ALL WE POPES A' NO LOSER Suu E ANN C -509 RESILIENT SCAT VALVES. B. maw BLOW Sut E INSTALLED .7. NO. NO AS DON ON Pt OR/S7 YM DETAILS CONTAINED IN TEE 0.06. 10. ALL VALrES 9ULL E FLANZED TO !IE TEE OR DOSS. CWT... SPNL NOTIF. DISTRICT • NININn OF :1 ,qRS fN ADrANCE W ALL EOESTS FOR SlulNS fESIINS OR INSPECTION. 11. DE.OPER/CDNTRACTOR IS ESTr61BLE FAR CONTROL REWIRED AI Rif TINE O ST.RIM. 1S. CON/RAC/OR SULI FOOI44 4EV ONANIACS FOR APPWAL NIEE REWIRED Or NNE DETAIL SPECIFICATIONS NO FOR VARIATION FRON NE APPRO. DESIGN. 14. ALL LIve 9ULL BE OIRECIL r SPERVISED Br AN ANN., D EPRESENT.IK OF NATER Ors RICINO. 75. 15. PIPE SNITn MOTILE IRON OVAL COAPESSI. TAPPING SEEK w. I -16 NIIn , ArO V.S. PIPE NU LATE PAL. No. 6660 ON RONAC •SST• STAINLESS S • uyTEEL TAMP. S K EfYE AREWIRED FOR LIVE TAPS TO OuC11LE .M [AST IRO/ PIPE. NEL_ER NEONANICAI JOINT War,. S:EFK NO N -615 B!M CLASS 115 OI -F• OR N,wC 16. CONTRACTOR IS RESPONSIBLE FON vERIFTIN: ALL EAISI:NS PIPE IM1ES u0 SITES 17. G221 6*1S CMCCIIOK 401 TAPS. N.lM lNE PIE Shut. wYE • SAL /2 FOOT 4144.4 COYER. 7 DE.PLCPER TO PAT FOR STATE. CI, NO COLN, INSECT,. NO PEWIT FEES. �9. COOOIINAIE of. LOCATIONS NUN NA. DISTRICT NO. 75 SPENINIEACENT, FIE NIDRANIS AIO BARS TOE OPERATIONAL PRIOR 10 CONENCENENT OF BUILD,. r°a6rlurla. DATED SCALE %4_ 40• TUKWAA, WASHINGTON RAINIER RIDGE WATER PLAN JOB NO. 708 SHEET C -9 OF 13 \ 1 ?; t V n1e`+J V .7oa ta 1107000 .111,e1e Inzu,sagosta room • ell= town ..r.narrs NOM 11.1(1 •Mr111 SIIVIDOSSV ?TIOd INN/MIA/1 -.« oN1 rfincl J. - Mp11A.T2 1C•.ta I.lnulaninw1 _ �111IIn4iuuln. /11 '� III 11111111111110 M 111 £ -� =rte I��Ililllll1111111� I III IIIIIIIIIIIIIII� VI.. AgJi111IU11i. Y-- -1I 1 •'Ii1.1111IIIIN= tiJ O ■•mw • 'v_1..., - Q 19"1 IT i. 11111;i111; lip 11.a I1 it ii ••l.0 f • M O (, 11.,. ,nn _I • 2X10e_ LCD3 /4 )c, 2,4 I , C�,G 3, 41. o0 to Uto A 0 ) • 1 11 ® 11 I�I 1 1 0 2.xloeI(,�c N ?e Io w r� W • E 16% OW 4L1434). 67L 6, 3/4 %; /4_ I - -1 pw TYPICAL FIRST FLOOR AND FOUNDATION PLAN NOTE 1 /8 "= 1-0,. TYPICAL FOR DOUBLE UNIT 2A AT BUILDINGS A, B AND C. OTHER UNIT ARRANGEMENTS SIMILAR. UNIT 2A IS THE WORST CASE SITUATION. 1VOO1 311d 0 Z n c 0 m 0 -1 EL. ? 7'�a EL. 248' SECOND 239. _ T / / ✓�_._..._ typical section for buildings a,b, and c P rC GL!J= -2F/"2 i°LFrN 11 I1IItlIlllll;Illl i' Illllill {•III111111 1111111111I(Pai 1111 1!Ill;u1111111 ■1 IN E1IIIII111111111111IIII 11111!1111111i111111111 EAST ELEVATION BLDG "A" r-- 11 '111 IIl 111111111111111'.I lkl !EI!'llll!IltllillllllllE!ll! 11 IIIIIIIIIIIIIIIIIiIII'.I 1® 11111111111111111111111 Ai. 111■ MIMI 1111II!111!II11lII1 lll dim mint il1! 1 ME RE 161111111 1iIIIIIIiI lllllllFII31;111lIIIIIL't !i111111111111111111111 11111 I1111111!Iiilllli i I IIII111111I1111l1i6 'IIIIIIIIIIII = dit!illlllli 111111111111111111111 '11 1111111 I111111111111II1 •, IIIIIIIIIIIIIIIEIIIIII IIIIIIlllUlI IIltllli l_ 7 I1111131111111111.111111 11 IIllIIIIIIIillllitlil .IhItlIItI!IIIIIIIilllil EAST ELEVATION BLDG `B" ■■ ■ 1111111111111111111111 ■ ■■ 111111111111111111111 ■ 111►11111I II I►1►I II I I I I ■■ 11111111111111111111111 IN ■ 1111111111111111111111 ■ ■■ 111111111111111111111 ' ■■ 11111111111111111111111 ■■ 111111111111111111111N EAST ELEVATION BLDG "C" Al - ■■ ■■1■ ■1■■ 1IIIIIIIIIIIIIIIIIIIII IIIlIIllIIIIJIIIIIII1I IIIIIIIIIIIIIIIII.1 1 11111111111111111111111 II1•IIIIU 1111111111111111111111 11 111111111111111111111 u•u•um1• ■■ ■■ IIIIIIIIIIIIIIIIIIIIIII- IIIIIIIIIIIIIIIIIIIIII EN EN. 111111111111111111111111 II 1UIl1111►►luumi 111111111111111111111 RAINER RIDGE APARTMENTS 111111IIIII•II•11 1 111111111111111 SHEET 3.1 SCALE 1 " =20' NORTH ELEVATION BLDG "D" Wra 1111111'1111F NORTH ELEVATION BLDG "E" 11111111IIII" NORTH ELEVATION BLDG "A" 11 NORTH ELEVATION BLDG "C' Jl� NORTH ELEVATION BLDG "B" SIMILAR • • RAINER RIDGE APARTMENTS SHEET 3.2 SCALE 1 " =20' WEST ELEVATION BLDG "A" WEST ELEVATION BLDG "B" RAINER RIDGE APARTMENTS SHEET 33 SCALE L" =20' WEST ELEVATION BLDG "E" WEST ELEVATION BLDG "C' SHEET 3.4 SCALE r=20' 44 44 pplo,,,,711 EAST ELEVATION BLDG "A" il Imimmum ME 1111111111111111111111 1111111111111E11 El 111111111111 I 111111111111 .1-1 111111111111 -- 111111111111 1 ME 1111111111111111111111 11 1111111111111111111111 11111 IIIIIIIIohIIIjIIIIIIt NM II 111111111111111111111 111111111111 111111111111 RAINER RIDGE APARTMENTS ummommo EAST ELEVATION BLDG "13" /NI ■-`41 ME 11111111111111111111111 EN Iminthinimm 1111 111111111111111111111111 111111111111111111M 111 Ell mlimillimilmilii iliiimmimmilill SHEET 3.5 SCALE r= 20' SOUTH ELEVATION BLDG "E" SOUTH ELEVATION BLDG "A" 1 11111111111 II SOUTH ELEVATION BLDG "D" SOUTH ELEVATION BLDG "B" SOUTH ELEVATION BLDG "C" • RAINER RIDGE APARTMENTS SHEET 3.6 SCALE 1 " =20' li 1------ 111 1— 1 ---, 1111111111111 1111111111111 i aittsmssir _ i , 1111111111111---1111111111111 IIfflhIIIIIIIIllIllll IIIIIIIIIII�IflhIIIItII uui 111111111111111111111111 111111111111111111111 •iui ii 111111111111111111111111 11111111111111111111111 EAST ELEVATION BLDG "D" II Ell 1111111111111111111111 U1• 1111111111111111111111 RAINER RIDGE APARTMENTS WEST ELEVATION BLDG "D" SHEET 3.7 SCALE 1"=20' G •arlMlw - PM .. DtAVX 9i_' MOD �i7E - P;_AN RAINIER RIDGE LANDSCAPE MASTERPLAN Scale 1': 30' -0" �� \7�:Jl: Landscape Architecture / Site Planning / Urban Design • �1,r , Suite 4!2.911 Wes!ern Avenue Seci1110 WA98109 682-7562 .