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HomeMy WebLinkAboutSEPA E96-0026 - BOEING - DUWAMISH RIVERBANK STABILIZATIONBOEING DUWAMISH RIVERBANK STABILIZATION S. 102ND ST. E96-0026 FOM Inc FACILITIES t7o lcompany Uxumlo Fa S . Corrninnu TO 1 DEPARTMENT OF FISHERIES Tnlaplwnu 2064313665 From Cui Ipany, Lowt w i Fin* °demi I%sposiliun: 1996. 10-09 pc.., Dclr1. l'Annpo lelnphone # 12116PM 14126 P.01/03 syf/.w7s Return U Ca1I la ddcup Alf"4/7€`4e4 *e -'1'°;44:1#141-f'' fi CEIVED 0Cr ' ?AS HYDRAULIC PROJECT APPROVAL R.G.W. 75.2 0.100 R.C.W. 75.20.103 E October_ 3, 1996 _ (applicant should refer to thio dato in ell eorrerspondence) PAGE 1 Or 3 PAGES L� TO LAST NAME FIRST 1p ONTACT PHONE(S) Boeing Defense & Space Group LLJ (206) 544-2975 pi] STREET Ok-KURTC-EbUTE P.O. Box 3707, MS 46-87 ATTN: Terry Bennett Seattle -------- Seattle --" NATE 98124--2207 TR TORY TO r"ATER Elllot B_.L_ li l _ _ DuwamRiver ivar _ idiIiTER SECT IOM _ TOWNSHIP_ _ , ._ _ RANGt (E -W) COUNTY _ - SECTION NESE 04 23N 04E King oCONTROLER 00 RC3544-01 L•r 14 jq YRIA u 09.0001 17 11JTYPE OF PROJECT Bank Protection "" S-) THIS PROJECT MAY SEG1N C 1AND MUST RE COMPLETED WI TIME LIMITATIONS: �immediately ?. December 31,1999Yry THIS APPROVAL, is ISREAVaill-A ,LIZNTHE JS SINAI' ALL TIME&,JJ D TTS PROVISI , S FOLLQ D BY THE PL$NITTEE AND 9PERA1Q&Ft RFORMINC THE WORK. SEED &1 ORTANT LNKRAL I'RQ.Y151ONSS1N REVI:IISE.S11ILDF. iO.VAL 1 1. NOTIFICATION RE UIREMENT: The permittee or contractor shall notify the Area Habitat Biologist listed below, by FAX at .(206) 391-6583 or mall at Washington E 22516 SE 64th Place, Issaquah, Washington 98027, of the project startadate. Notificationdshallysiboe receiv+�ed by the Area Habitat Biologst start of construction activities. The notification shall include the per.Tnittee's name, project location, starting date and the control number for this Hydraulic 2. ADDITIONAL TIMING LIMITATIONS: Work below the ordinary high water line (OHWL) shall be completed by December 37, 1996. Revegetation per Provision 11 shall becompleted no later than December 31, 3996, and shall; be monitored through December. 31, 1999. 3. Work shall be accomplished per plans and specifications entitled, "Duwamish West River Bank Stabilization River dated June 12 1996, and August 7, 1996, and submitted to WDFW, except as modified by this HPA. These plans reflect design criteria per Chapter • 22tT 110' WAC -2s. • ..opy of thoco pl-ans shall lug ava3..a able on site during construction. 4. Be Bank prcr otetioodiokbshal]. be restricted to work necessary to p sEPA: DNS, City of Tukwila REGIONAL HAST AT MANAGER - Philip Schneider (206) 391--4365 PATROL - Frame 024 [P2) • APPLICANT - WILDLIIC - READER - PATROL - HAD. MGR. - WRIA DEPARTMENT OF FIBHERIEB R, �- .3Y�• ��� DIRECTOR -FROM :DC FACILITIES DEPARTMENT OF FISNFRIES • TO 2064313665 HYDRAULIC PROJECT APPROVAL 416.10-08 12:16PM #125 P.02/03 R.C.W. 75.20.100 R.C.W. 75.20.103 ©_.. October 3, 1996 __ ( (eppl..ont chould refer to this date in all correspondence) PAOE3.OF 3 PAGES [fOILAST NAME WICONTACT PHONE(S) Boeing Defense & Space Group (206) 544-2975 I17ILMTEI:puwamist1 River CONTROL NUMBER 00-C3544-01 nYRIA 09.0001 5. Placement of bank protection material waterward of the thecOHthesh�allof be restricted to the minimum amount necessary to prthe bank or for installation of mitigation features approved by WDFW. 6. The toe shall beinstalled to protect the integrity of bank protection material. 7. Bank sloping shall be accomplished in a manner annerrthatmavoids release of overburden material into the water. resulting from the project shall be deposited so it will not re-enter the water. 8. Bank protection material shall be clean, angular rock and shall be installed e1oblashlOoapsefswr gor ohrroundcobesalntbeudaexteriorarmor. 9. Bank protection and filter blanket material shall be placed from the bank. Dumping onto the bank afaceashallan be permittedtonly yeif the toe is established and the m bank face. 10. Fish habitat components, such as logs, stumps, and/or.largge boulders, are required as part of the bank ,prrotectioneprojectltobeitigateled toowithstandc100-years peaks flows. p 11. Alteration or disturbance of the bank and bank vvegetationishal] be limited to that necessary to construct the prof tt calendar days of project completion all disturbed areas shall be protected from erosion using vegetation or other means.' Within one year of project completion the banks, includingriprap areas, shall be revegetated an indicated80inethenplans mainained as necessary for 3 years to ensurep 12. The fish habitat structures shall be of fir, cedar, or other approved coniferous species. 13. Erosion contro]_Dethods shall be used to prevent silt -laden water from entering the stream. These may includde,uaenot t limited to, straw bales, filter fabric, temporary but-are k dams of pea gravel -filled burlap ebags or other material, and/or immediate mulching of expo 14. lveresultinghfromcthisrproject, shall bel deposited above or overburden the limits of flood water in an approved upland disposal site. REV 10/16/88 _.FROM :DC FACILITIES DEPARTMENT Of FISHERIES TO • 2064313565 1996,10-08 • HYDRAULIC PROJECT APPROVAL R.O.W. 75.20.L00 R.C.W. 75,20.103 October 3, 1996 _ (applicant shpuld refer to this date In all correspondence) PAGE'S OF 3 PAGES 10 LAST NAME 18 ONIACT PHONE(S) �� Boeing Defense & Space Group (206) 544-2975 (1fl11ATERnuwamish River 12:16PM #125 P.03/03 D (404941+4650 CONTROL NUMBCR 00-C3544--01 9 WRIA 09.0003 15. Extreme care shall be taken to ensurhtsnoipett petroleum products, hydraulic fluid, fresh cement, sediments, chemicals, ore any otherttoxicrormdeleterious materials are allowed to enter 16. Excavation and the placement of rock and habitat structures shall be done in the dry during low tide. 1'/. This project steal] be acommpliehed in a manner so that thereppwill be no exposed and disturbed areas left unprotected bydriprtp, mulch, weekend,cortholidays�c or matting LOCATION: South 102nd Street upstream from the Boeing Bridge in Tukwila bk REV 10/16/88 RCPL ATTENTION TO ATT HN i3ON O/ Regulatory Branch • DEPARTMENT OF THE ARMY SEATTLE DISTRICT. CORPS OF ENGINEERS P.O. BOX 3755 SEATTLE, WASHINGTON 98124-2255 4 j/7e [ elT C-62 . 10500 I/1/81 1 vl/a- . aen;H-ne) V//1 q(?1 Reference a� �( Dear , -rit 12.rYle ✓l RecoN'' SEP 2,6 1996 ®GooVsreca ESE //1 'We re ent,1y receiyed a copy of the following informatia. from 1 -/Lt -G7 0 _ __ _ concerning _y_our_p 'posed project. Determination of Nonsignificance Shoreline Permit Environmental Checklist Other: Your project may require authorization from the U.S. ArY Corps of Engineers under the following regulations. ( ) Section 10 of the Rivers and Harbors -=t ( ) Section 404 of the Clean Water Act A Section 10 permit is required for const r Ction in or :ver any navigable waters of the United States. A Section 404 perr-`t is requir'- for the discharge of dredge or fill material in waters the Unite. States, including wetlands. The term "discharge of dredged material" rr..- ns the addi ion, including redeposition, of dredged material or excavated soils. These activities can include grading, mechanized landclearing, disc::.=g. channel::ation, and other excavation activities that destroy or degrade ;oa=ers of the ;'nited States, including wetlands. The term "discharge of fi:._ material" moans the addition of any material used for the primary purpose ca creating dry' land or of changing the elevation of water of the United i ates, including wetlands. The placement of piling constitutes a discharge materia when such placement has or would have the effect of a d=s=.arge of fi l material. Wetlands mean those areas that are inunda r= or satura:'ed by surface or ground water at a frequency and duration suff:.=nt to supp` normal circumstances do support, a prevalence rt, and that under vegetation for life in saturated soil conditions. typically adapted Please contactteleph�e (206) 764 permit concerning specific permit requirements. Enc_ ed for your use is our p pamphlet and necessary application materials. Sincer:_:' Robert Chief, Enclosures i.jL/ cc: G/1 -d' 64- 77-1,Ie-cvit./a_, -7Ickkt/ ,lvA `%, i5u sr Martin -cessing AFFIDAVIT , Nl1i` -6A LI Notice of Public Hearing []Notice of Public Meeting O Board of Adjustment Agenda Packet O Board of Appeals Agenda Packet []Planning Commission Agenda Packet fl Short Subdivision Agenda Packet 0 Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit OF DISTRIBUTION hereby declare that: fl Determination of Non- significance D Mitigated Determination of Nonsignificance fl Determination of Significance and Scoping Notice O Notice of Action 0 Official Notice Other []Other was mailed to each of the following addresses PTA 04 el) 61-f on Ct-25 —9(a Name of Project bU J AA(SNI NMt Signature e I V V' 1d2L- U File Number';.%40-002'..149 1 ijUl/&T City of Tukwila • • John W. Rants, Mayor Department of Community Development Steve Lancaster, Director September 24, 1996 NOTICE OF FINAL THRESHOLD DETERMINATION SUBJECT: - LOCATION: File E96-0026 The Duwamish Riverbank at 7 locations in the vicinity of South 102 Street SEPA DETERMINATION: Determination of Non -Significance issued September 6, 1996 This notice is to inform you that the 15 day comment period for the threshold determination expired without substantive comments from the public or agencies with jurisdiction. The City of Tukwila will retain the Determination of Non -Significance issued on September 6, 1996. Project materials including the application, any staff reports, and other studies related to the permits are available for inspection at the Tukwila Department of Community Development; 6300 Southcenter Boulevard; Suite 100; Tukwila, WA; from Monday through Friday, between 8:30 AM and 5:00 PM. The project planner is Nora Gierloff who may be contacted at 431-3670 for further information. Property owners affected by this decision may request a change in valuation for their property tax purposes notwithstanding any program of revaluation. The time period for appeals is 14 days starting from the date of this notice, September 24, 1996. Copies of the procedures for SEPA appeals are available with the Department of Community Development. 6300 Southcenter BoulevarcL Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 City of Tukwila • Department of Community Development :.: 6300 Southcenter Boulevard Tukwila, WA 98188-2599 Terry Bennett BOEING DEFENSE AND SPACE GROUP PO Box 7307 M/S 46-87 Seattle, WA 98124 MUCKLESHOOT INDIAN TRIBE 39015 172nd AVE SE AUBURN, WA 98092 D'JWAMISH INDIAN TRIBE 140 RAINIER AVE S - STE 7 RENTON, WA 98055-2000 WASH FISHERIES/WILDLIFE 16018 MILL CREEK BLVD MILL CREEK, WA 98012 City Of Tukwila Department of Community DlePelopment 6300 Southcenter Boulevard Tukwila, WA 98188-2599 p - I. VLtI LL isoa Tukwila, WA 98188-2599 • DEPARTMENT OF ECOLOGY SEPA REVIEW SECTION PO BOX 47703 OLYMPIA, WA 98504-7703 US CORP OF ENGINEERS 4735 EAST MARGINAL WY S SEATTLE, WA 98124-2255 an of mmlwiuP Ruguc, ;WT.: foao Sou.-rFie�N�e wAl8igg' CITY OF TUKWILA DETERMINATION OF NONSIGNIFICANCE (DNS) DESCRIPTION OF PROPOSAL: RIVERBANK STABILIZATION ALONG TRAIL PROPONENT: THE BOEING COMPANY LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ADDRESS: PARCEL NO: SEC/TWN/RNG: LEAD AGENCY: 10500 WEST MARGINAL PL S 042304-9150 SE/04/23/04 ANY: CITY OF TUKWILA FILE NO: E96-0026 The City has determined that the proposal does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21c.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. * * * * * * * * * * * * * * * * * * * * * * * * * * *'* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * This DNS is issued under 197-11-340(2). comments must be submitted by _ SCCI Q't. 234-15% . The lead agency will not act on this proposal for 15 days from the date below. �-�-� S Prt'M8t-✓Z 6 L 19 q 6 Steve Lancaster, Responsible Official City of Tukwila, (206) 431-3680 6300 Southcenter Boulevard Tukwila, WA 98188 Date Copies of the procedures for SEPA appeals are available with the Department of Community Development. AFFIDAVIT I, 9/alik PAc1 ulU-Ei\‘ LI Notice of Public Hearing O Notice of Public Meeting O Board of Adjustment Agenda Packet fl Board of Appeals Agenda Packet flPlanning Commission Agenda Packet 0 Short Subdivision Agenda Packet O Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit OF DISTRIBUTION hereby declare that: Determination of Non- significance 0 Mitigated Determination of Nonsignificance Determination of Significance and Scoping Notice Notice of Action Official Notice Other Other was mailed to each of the following addresses on cl (see-- MAF A crA c -k S►� FT> Name of Project 1 k- Signature File Number °I(40- 0026ABILI City of Tukwila Department of Community Development 6300 Southcenter Boulevard Tukwila, WA 98188-2599 Tukwila, WA 98188-2599 Terry Bennett BOEING DEFENSE AND SPACE GROUP: PO Box 7307 M/S 46-87 Seattle, WA 98124 MUCKLESHOOT INDIAN TRIBE 39015 172ND AVE SE AUBURN, WA 98092 DUWAMISH INDIAN TRIBE 140 RAINIER AVE S - STE 7 RENTON, WA 98055-2000 WASHINGTON STATE DEPARTMENT OF WILDLIFE & FISHERIES 16018 Mill Creek Blvd. Mill Creek, WA 98012 %, • `•t. City of Tukwila Department of Community Development .'••• . 6300 Southcenter Boulevard 19oB ; : = Tukwila, WA 98188-2599 US ARMY CORP OF ENGINEERS 4735 East Marginal Way South Seattle, WA .98124-2255. CITY OF TUKWILA 6200 SOUTHCENTER BLVD. TUKWILA, WA 98188-2599 (206) 433-1800 TO: DEPARTMENT OF ECOLOGY SEPA REVIEW SECTION PO BOX 47703 OLYMPIA, WA 98504-7703 F vo A- F,- - F } uLt50c vA)012. Y _6 3(70 SoLM- ?EI2 ( Lub , WA,i 1. • AFFIDAVIT I,6\/J.Am -- O Notice of Public Hearing fl Notice of Public Meeting O Board of Packet O Board of Packet Adjustment Agenda Appeals Agenda L Planning Commission Agenda Packet f Short Subdivision Agenda Packet O Notice of Application for Shoreline Management Permit LIShoreline Management Permit • OF DISTRIBUTION hereby declare that: VDetermination of Non- significance fl Mitigated Determination of Nonsignificance • O Determination of Significance and Scoping Notice Notice of Action Official Notice Other Other was mug=la to each of the following addresses "T1 AA 5 on "►-L - 11P Name of Pro j ectbUL11AN\ XSt4 NER B,AIIK, S ignature flfluDJ1& B LIZailoK5 File Number EL ' 002-(P CHECKLIST: ENIRONMENTAL REVIEW/SHORELIN ERMIT MAILINGS (U.S. ARMY CORPS OF ENGINEER/ () FEDERAL HIGHWAY ADMINISTRATION () DEPT OF FISH & WILDLIFE () OFFICE OF ARCHAEOLOGY () TRANSPORTATION DEPARTMENT O DEPT NATURAL RESOURCES () OFFICE OF THE GOVERNOR () DEPT OF COMMUNITY DEVELOPME VI.DEPT OF FISHERIES & WILDUFE7 () KC. PLANNING & COMMUNITY DEV. () BOUNDARY REVIEW BOARD () FIRE DISTRICT #11 () FIRE DISTRICT #2 () S CENTRAL SCHOOL DISTRICT () TUKWILA UBRARIES () RENTON UBRARY () KENT UBRARY () CITY OF SEATTLE LIBRARY ()USWEST () SEATTLE CITY UGHT () WASHINGTON NATURAL GAS () HIGHUNE WATER DISTRICT () SEATTLE WATER DEPARTMENT ( ) TCI CABLEVISION () OLYMPIC PIPEUNE () KENT PLANNING DEPT () KWILA CITY DEPA ENTS: PUBUC WORKS ( ) FIRE POUCE ( ) FINANCE () PLANNING ( ) BUILDING () PARKS & REC. ( ) MAYOR () PUGET SOUND REGIONAL COUNCIL () P.S. AIR POLLUTION CONTROL AGENCY () SW K C CHAMBER OF COMMERCE MUCKLESHOOT INDIAN TRIB DUWAMISH INDIAN TRIB�/ () DAILY JOURNAL OF COMMERCE () VALLEY DAILY NEWS 7/12/95 C:WP51 DATA\CHKLIST FEDERAL AGENCIES () U.S. ENVIRONMENTAL PROTECTION AGENCY () U.S. DEPT OF H.U.D. WASHINGTON STATE AGENCIES () DEPT OF SOCIAL & HEALTH SERV. () DEPT OF ECOLOGY, SHORELANDS Q4DEPT OF ECOLOGY, SEPA DIVISION () OFFICE OF ATTORNEY GENERAL * SEND CHECKUST WITH DETERMINATIONS * SEND SITE MAPS WITH DECISION KING COUNTY AGENCIES () KC. DEPT OF PARKS () HEALTH DEPT () PORT OF SEATTLE () BUILDING & LAND DEV. DIV -SEPA INFO CENTER SCHOOLS/UBRARIES ()HIGHUNE SCHOOL DISTRICT () K C PUBUC UBRARY () SEATTLE MUNI REF UBRARY () SEATTLE SCHOOL DISTRICT () RENTON SCHOOL DISTRICT UTILITIES () PUGET SOUND POWER & LIGHT () VAL-VUE SEWER DISTRICT () WATER DISTRICT #20 () WATER DISTRICT #125 () CITY OF RENTON PUBUC WORKS () RAINIER VISTA () SKYWAY CITY AGENCIES () RENTON PLANNING DEPT () CITY OF SEA -TAC () CITY OF BURIEN ( ) TUKWILA PLANNING COMMISSION MEMBERS ( ) TUKWILA CITY COUNCIL MEMBERS OTHER LOCAL AGENCIES () METRO ENVIRONMENTAL PLANNING DIV. OFFICE/INDUSTRIAL 5,000 GSF OR MORE RESIDENTIAL 50 UNITS OR MORE RETAIL 30,000 GSF OR MORE MEDIA () HIGHUNE TIMES () SEATTLE TIMES • • PUBLIC NOTICE MAILINGS FOR PERMITS SEPA MAILINGS Mail to: (comment period starts on date of mailing) Dept. of Ecology Environmental Review Section Applicant Other agencies as necessary (checked off on attached list) Include these documents: SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS) SEPA Checklist (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Affidavit of Dlstribution (notice was mailed & sent to newspaper). SHORELINE MAILINGS Notice of Application: Notice of application for a substantial development Permit must be mailed to owners and to property owners within 300 feet of subject property, prepare an affidavit of publication, and publish two consecutive weeks with deadline for comments due 30 days after last newspaper publication date. Shoreline Permit: Mail to: (within 8 days of decision; 30 -day appeal period begins date'received by DOE) Department of Ecology Shorelands Section State Attorney General Applicant Indian Tribes Other agencies as necessary (checked off on attached list). Include these documents: Shoreline Substantial Development Permit (3 -part form from Sierra) Findings (staff report, if applicable) Shoreline Application Form (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Site plan, with mean high water mark & improvements Cross-sections of site w/structures & shoreline Grading plan Vicinity map SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS) SEPA Checklist (filled out by applicant) Any background studies related to impacts on shoreline Notice of Application Affidavit of Distribution (notice was mailed & sent to newspaper) Affidavit of Publication (notice was published in newspaper). Memorandum TO: Jack Pace 61 FROM: Nora Gierloff RE: SEPA - Duwamish West Riverbank Stabilization DATE: September 4, 1996 Project File No. E96-0026 Project Description: The Boeing Company has applied for permits to stabilize the west riverbank of the Duwamish River at seven locations along a 2,300 foot stretch. Six areas are south of S. 102 Street and one is approximately 400 feet north of S. 102 Street. The seven areas total approximately 350 feet. The western edge of all of the areas is bordered by a cinder surfaced walking trail which is to remain in use. Agencies With Jurisdiction: Washington State Department of Fisheries U.S. Corps of Engineers Comments to SEPA Checklist: The Muckleshoot Indian Tribe Fisheries Department has concerns that the proposed woody debris might interfere with tribal fishing rights. The Tribal Environmental Division will address such concerns through the Corps of Engineers regulatory review process. Summary of Primary Impacts: 1. Earth - Soil will be disturbed during the process of placing quarry spalls, rip rap, and vegetated geogrid. The intent of this action is to prevent additional slumping at the seven sites and so control future erosion of the bank. 2. Air - There will be exhaust emissions from construction equipment during the project. Dust control measures in compliance with the Puget Sound Air Pollution Control Authority will be used as needed. The project will have no air emissions when complete.' 3. Water - The natural flow of stormwater into the River will not be impeded by this project. No wastewater will be discharged into the River as a result of this project. 4. Plants - Grass, water plants, blackberries, willow, and scotch broom will be removed from the slumping areas. Disturbed areas will be replanted with willows and grass in vegetated geogrid. • • 5. Animals - The Duwamish is a migration route for salmon. Woody debris will be installed in the riverbank to enhance fish habitat. The reconstructed banks will be curved rather than straight to allow for eddies. 6. Energy and Natural Resources - The project will require energy for construction equipment and for vehicles coming to the site. 7. Environmental Health - No environmental health hazards are anticipated. Construction equipment operation will need to comply with Tukwila's noise ordinance. 8. Land and Shoreline Use - The proposed project will help preserve the existing use of the site as a walking trail. 9. Housing - The proposal will not result in a change to the housing supply. 10. Aesthetics - The project is not subject to BAR requirements. 11. Light and Glare - The proposal will not generate light or glare. 12. Recreation - The proposal will preserve the existing walking trail where it is near the seven slumping areas. 13. Historical and Cultural Preservation - The site is not known to have any historical or cultural significance. 14. Transportation - Moving one section of the trail farther away from the bank would result in a loss of four parking spaces. 15. Public Services - The project will not increase demand on public services. 16. Utilities - The project will not affect utility use. Recommended Threshold Determination: Determination of non -significance. MUCKLESHOOT INDIAN TRIBE FISHERIES DEPARTMENT 3 September 1996 Ms Nora Gierloff Department of Community Development City of Tukwila Suite #100 - 6300 Southcenter Boulevard Tukwila, Washington RE: NOTICE OF APPLICATION FOR BOEING TO STABILIZE TIDE DUWAMLSH RIVERBANK AT SEVEN LOCATIONS IN THE VICINITY OF SOUTH 102ND STREET Dear Ms Gierloff: The Environmental Division of the Muckleshoot Indian Tribe has reviewed the proposal to stabilize seven locations along the Duwamish River. The use of large woody debris and vegetation should help to reduce impacts to the natural environment. However, members of the Muckleshoot Indian Tribe fish for salmon in the vicinity of the proposed bank stabilization. The potential exists for the proposed bank stabilization to interfere with the exercise of Treaty fishing rights. The Tribal Environmental Division will address such concerns through the Corps of Engineers regulatory review process. By copy of this letter, the Tribal Environmental Division requests to be notified by the Corps of Engineers upon an application by Boeing for a Corps permit. -- - If you-have.a.ny_ouestions_concerning this letter, please feel free to phone me at (206) 931-0652 extension 119. cc: Corps of Engineers / Regulatory Branch WDFW inc re Roderick Malcom Habitat Biologist RECEIVED SEP 0,5 1996 COMMUNITYFn pp39015 172nd Avenue S.E. • Auburn, Washington 98092 • (206) 931-0652 • FAX (206) V075�'PMENT AFFIDAVIT• OF DISTRIBUTION I, 91L \I A MMu hereby declare that: O Notice of Public Hearing O Determination of Non- significance O Notice of Public Meeting fl Mitigated Determination of Nonsignificance L Board of Adjustment Agenda E Determination of Significance Packet and Scoping Notice O Board of Appeals Agenda Packet flPlanning Commission Agenda Packet 0 Short Subdivision Agenda Packet Notice of Action Official Notice NI Other 'hT IC- OF AFPLICA11OI fl Notice of Application for Li Other Shoreline Management Permit JShoreline Management Permit was mailed to each of the following addresses on (5cf. ki-vAcab 61 -t -k) Name of Project6KiAt4\ S14 VW BAr'* Signature File Number rte- io ' �fA-61 u ZI�T1o�I 23-96 �... qA(610EQ,_ 1 llepai t/PICPLL vj idcv lUpitteitt 6300 Southcenter ' levard Tukwila, WA 981: .99 Nkttui3&Lac luKWna, VVH YoRSO-LJYY DEPARTMENT OF ECOLOGY SEPA REVIEW SECTION PO BOX 47703 OLYMPIA, WA 98504-7703 US ARMY CORP OF ENGINEERS 4735 East Marginal Way South Seattle, WA 98124-2255 MUCKLESHOOT INDIAN TRIBE 39015 172ND AVE SE AUBURN, WA 98092 DUWAMISH INDIAN TRIBE • 140 RAINIER AVE S - STE 7 RENTON, WA 98055-2000 AFFIDAVIT I, SNI LVIA McMu LLE O Notice of Public Hearing fl Notice of Public Meeting ElBoard of Adjustment Agenda Packet L Board of Appeals Agenda Packet Planning Commission Agenda Packet 0 Short Subdivision Agenda Packet OF DISTRIBUTION hereby declare that: fl Notice of Application for Shoreline Management Permit LJShoreline Management Permit fJDetermination of Non- significance Mitigated Determination of Nonsignificance Determination of Significance and Scoping Notice ❑ Notice of Action O Official Notice Vothert\IOnc.O .A ftcA I QIJ Other was.lai1ed to each of the following addresses FAXab TIMES on 2.22---9U Name of Project1\I1MNLS1-Rhleg-1 \ signature - File Number 1�cil- DD2t0 5rAalL12l� CITY OF TUKWILA NOTICE OF APPLICATION PROJECT INFORMATION The Boeing Company has filed applications for stabilization of the Duwamish Riverbank at seven locations in the vicinity of South 102 Street. Permits applied for include: Flood Control Zone Hauling Land Altering Shoreline Permit Exemption Other known required permits include: Corps of Engineers Section 10/404 Hydraulics Project Approval An environmental checklist has been submitted with the studies identified above. FILES AVAILABLE FOR PUBLIC REVIEW The project files are available at the City of Tukwila. To view the files, you may request them at the counter at the Department of`Community Development (DCD), located at 6300 Southcenter Boulevard #100. Project Files include: E96-0026 - Environmental Checklist L96-0041 - Shoreline Permit Exemption P96-0059,- Utility Permits OPPORTUNITY FOR PUBLIC COMMENT Your written comments on the project are requested. They must be delivered to DCD at the address above or postmarked no later than 5:00 P.M., September 4 1996. APPEALS You may request a copy of any decision, information on hearings, and your appeal rights by calling DCD at 431-3670. The City of Tukwila permits applied for are Type 1 decisions appealable only to, Superior Court. For further information on this proposal, contact Nora Gierloff at 431-3670 or visit our offices at 6300 Southcenter Boulevard, Suite #100, Monday through Friday, 8:30 a.m. to 5:00 p.m. Application Filed: July 25, 1996 Notice of Completeness Issued: August 6, 1996 Notice of Application Issued: August 21, 1996 III CHECKLIST: EN RONMENTAL REVIEW/SHORELINEERM:IT MAILINGS ( U.S. ARMY CORPS OF ENGINEER (r �) FEDERAL HIGHWAY ADMINISTRATION () DEPT OF FISH & WILDLIFE () OFFICE OF ARCHAEOLOGY ( ) TRANSPORTATION DEPARTMENT () DEPT NATURAL RESOURCES () OFFICE OF THE GOVERNOR () DEPT OF COMMUNITY DEVELOPMENT () DEPT OF FISHERIES & WILDUFE () KC. PLANNING & COMMUNITY DEV. () BOUNDARY REVIEW BOARD () FIRE DISTRICT #11 () FIRE DISTRICT #2 () S CENTRAL SCHOOL DISTRICT ( ) TUKWILA LIBRARIES () RENTON UBRARY () KENT LIBRARY () CITY OF SEATTLE UBRARY () U S WEST () SEATTLE CITY UGHT () WASHINGTON NATURAL GAS () HIGHUNE WATER DISTRICT () SEATTLE WATER DEPARTMENT ( ) TCI CABLEVISION () OLYMPIC PIPEUNE () KENT PLANNING DEPT ( ) TUKWILA CRY DEPARTMENTS: O PUBLIC WORKS ( ) FIRE () POUCE ( ) FINANCE () PLANNING ( ) BUILDING ( ) PARKS & REC. ( ) MAYOR () PUGET SOUND REGIONAL COUNCIL () P.S. AIR POLLUTION CONTROL AGENCY () SW K C CHAMBER OF COMMER MUCKLESHOOT INDIAN TRIB (( &DUWAMISH INDIAN TRIB () DAILY JOURNAL OF COMMERCE () VALLEY DAILY NEWS 7/12/95 C:WP51DATA\CHKUST FEDERAL AGENCIES () U.S. ENVIRONMENTAL PROTECTION AGENCY () U.S. DEPT OF H.U.D. WASHINGTON STATE AGENCIES () DEPT OF SOCIAL & HEALTH SERV. () DEPT OF ECOLOGY, SHORELANDS DN/ ('; DEPT OF ECOLOGY, SEPA DIVISION\"/ () OFFICE OF ATTORNEY GENERAL * SEND CHECKUST WITH DETERMINATIONS * SEND SITE MAPS WITH DECISION KING COUNTY AGENCIES () KC. DEPT OF PARKS () HEALTH DEPT () PORT OF SEATTLE () BUILDING & LAND DEV. DIV SEPA INFO CENTER SCHOOLS/LIBRARIES () HIGHLINE SCHOOL DISTRICT () K C PUBUC UBRARY () SEATTLE MUNI REF UBRARY () SEATTLE SCHOOL DISTRICT () RENTON SCHOOL DISTRICT UTILITIES () PUGET SOUND POWER & UGHT () VAL-VUE SEWER DISTRICT () WATER DISTRICT #20 () WATER DISTRICT #125 () CITY OF RENTON PUBUC WORKS () RAINIER VISTA () SKYWAY CITY AGENCIES () RENTON PLANNING DEPT () CRY OF SEA -TAC () CITY OF BURIEN () TUKWILA PLANNING COMMISSION MEMBERS () TUKWILA CITY COUNCIL MEMBERS OTHER LOCAL AGENCIES () METRO ENVIRONMENTAL PLANNING DIV. OFFICE/INDUSTRIAL 5,000 GSF OR MORE RESIDENTIAL 50 UNITS OR MORE RETAIL 30,000 GSF OR MORE MEDIA () HIGHUNE TIMES PQ SEATTLE TIME S✓ • • PUBLIC NOTICE MAILINGS FOR PERMITS SEPA MAILINGS Mail to: (comment period starts on date of mailing) Dept. of Ecology Environmental Review Section Applicant Other agencies as necessary (checked off on attached list) Include these documents: SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS) SEPA Checklist (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Affidavit of Dlstribution (notice was mailed & sent to newspaper). SHORELINE MAILINGS Notice of Application: Notice of application for a substantial development Permit must be mailed to owners and to property owners within 300 feet of subject property, prepare an affidavit of publication, and publish two consecutive weeks with deadline for comments due 30 days after last newspaper publication date. Shoreline Permit: Mail to: (within 8 days of decision; 30 -day appeal period begins date received by DOE) Department of Ecology Shorelands Section State Attorney General Applicant Indian Tribes Other agencies as necessary (checked off on attached list). Include these documents: • Shoreline Substantial Development Permit (3 -part form from Sierra) Findings (staff report, if applicable) Shoreline Application Form (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Site plan, with mean high water mark & improvements Cross-sections of site w/structures & shoreline Grading plan Vicinity map SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS) SEPA Checklist (filled out by applicant) Any background studies related to impacts on shoreline Notice of Application Affidavit of Distribution (notice was mailed & sent to newspaper) Affidavit of Publication (notice was published in newspaper). CITY OF TUKWILA DEPARTMENT OF COMMUNITY DEVELOPMENT 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 AFFIDAVIT OF INSTALLATION AND POSTING OF PUBLIC INFORMATION SIGN(S) State of Washington County of King City of Tukwila I (Print Name) understand that Section 18.104.110 of the Tukwila Municipal Code re ires me to post the property no later than fourteen (14) days following the issuance of the Notice of Completeness. I certify that on z the Public Notice Board(s) in accordance with Section 18.104.1 and other applicable uidelines were posted on the property located at /0_5 -DO Gly so as to be clearly seen from each right -of -way providing primary vehicular access to the property for application file numberf 9 �v - 00 5 4 1`• SUBSORIBED AND SWORN to before me thisday of Affiant (Applicant Signature) ,19� (tiW NOTAttV PUBLIC in and for the State of Washington residing at My commission exp t es on 6-7/ RECE VFD AUG 2 3 1996 COMMUNITY DEVELOPMENT CITY OF TUKWILA NOTICE OF APPLICATION PROJECT INFORMATION The Boeing Company has filed applications for stabilization of the Duwamish Riverbank at seven locations in the vicinity of South 102 Street. Permits applied for include: Flood Control Zone Hauling Land Altering Shoreline Permit Exemption Other known required permits include: Corps of Engineers Section 10/404 Hydraulics Project Approval An environmental checklist has been submitted with the studies identified above. FILES AVAILABLE FOR PUBLIC REVIEW The project files are available at the City of Tukwila. To view the files, you may request them at the counter at the Department of Community Development (DCD), located at 6300 Southcenter Boulevard #100. Project Files include: E96-0026 - Environmental Checklist L96-0041 - Shoreline Permit Exemption P96-0059 - Utility Permits OPPORTUNITY FOR PUBLIC COMMENT Your written comments on the project are requested. They must be delivered to DCD at the address above or postmarked no later than 5:00 P.M., September 4 1996. APPEALS You may request a copy of any decision, information on hearings, and your appeal rights by calling DCD at 431-3670. The City of Tukwila permits applied for are Type 1 decisions appealable only to Superior Court. For further information on this proposal, contact Nora Gierloff at 431-3670 or visit our offices at 6300 Southcenter Boulevard, Suite #100, Monday through Friday, 8:30 a.m. to 5:00 p.m. Application Filed: July 25, 1996 Notice of Completeness Issued: August 6, 1996 Notice of Application Issued: August 21, 1996 August 6, 1996 • City of Tukwila John W Rants, Mayor Department of Community Development Steve Lancaster, Director NOTICE OF COMPLETE APPLICATION Terry Bennett Boeing Defense and Space Group P.O. Box 3707 M/S 46-87 Seattle, WA 98124 RE: Duwamish Riverbank Stabilization E9,6=.0026 Dear Mr. Bennett: Your environmental checklist for stabilization of the Duwamish west riverbank has been found to be complete on August 6th for the purposes of meeting state mandated time requirements. The next step is for you to install the notice board on the site within 14 days of the date of this letter. You received information on now to install the sign with your application packet. If you need another set of those instructions, you may obtain them at the Department of Community Development (DCD). When you have installed the sign let me know so that I can give you a laminated copy of the Notice of Application to post on the board. After installing the sign with the laminated notice, you need to return the signed Affidavit of Posting to the our office. The 14 day public comment period will start once the Notice of Application is posted. This determination of complete application does not preclude the ability of the City to require that you submit additional plans or information, if in our estimation such information is necessary to ensure the project meets the substantive requirements of the City or to complete the review process. This notice of complete application applies only to the permits identified above. It is your responsibility to apply for and obtain all necessary permits issued by other agencies. There may be permits from other agencies required which we have not identified. If you have any questions feel free to call me at 433-7141. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 Notice of Complete Application Page 2 Sincerely, Nora Gierloff Assistant Planner cc: Joanna Spencer, Department of Public Works Mike Alderson, Fire Department Boeing Defense & Space Group P.O. Box 3999 Seattle, WA 98124-2499 July 30,1996 To: Washington Department of Fish and Wildlife 16018 Mill Creek Blvd. Mill Creek Wa. 98012-1296 Philip E. Schneider WO R.41 Mr. Schneider; I thank you for meeting me at the site to review the river bank stabilization job that Boeing Defense and Space is in the process of permitting thru The City of Tukwila. As we were walking the areas to be reconstructed you mentioned that the drawings did not show enough "Woody Debris" in each construction area. You said that the normal requirement in this area would be an average of a debris tree every 20 foot and that the root ball should point upstream at 30 degrees from the bank. You also stated we could bunch woody debris together in these areas if it would be easier to attach the debris to the river bark.. This letter is to inform you this will be taken care of during the construction and we will not resubmit revised drawings to you or the city. Please attach this to the drawings as a revision to the permit. Thank You for your time in this matter. Sincerely; Terry Bennett Boeing Defense and Space Group Box 3707 M/S 46-87 Seattle, wa. 98124 206-544-2975 RECEIVED JUL 311996 LI TUKWILC OP.KA'�\. PUBE RECEIVED CITY OF TUKWILA JUL 3 1 1996 '6‘ ' PERMIT CENTER CITY OF UKWILA Departmernf Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 RECEIVED CIN OF TUKWILA JUL 251996 PERMIT CENTER ENVIRONMENTAL REVIEW (SEPA) APPLICATION SUBMITTAL REQUIREMENTS. To submit for SEPA review, provide the items listed above to the Planning Division at 6300 Southcenter Boulevard, Room 100. ❑ 8 copies of the completed and signed environmental checklist. You may use the City's pre-printed form or you may re -type the questions on your computer. If you choose to re -type the form into your computer, be sure to do so accurately. Mistakes or omissions will increase the review time. 141 )3 sets of the full size plans needed to clearly describe the proposed action. 4 ci-e---Va One PMT set of plans reduced to 8.5" x 11". 9/ Four copies of supporting studies. g One copy of the checklist application. 6/4- One set of mailing labels for all properti s 500' from the subject property. (See address label worksheet.) 41/ i 7' $325 filing fee. COMPLETING THE CHECKLIST The checklist contains several pages of questions which. you are asked to answer. It covers a comprehensive set of topics. As a result, several of the questions may not apply to your project. If a particular question does not apply, simply write N/A undemeath. HOWEVER, be aware that many questions apply despite appearing not to. Care needs to be taken in reading and answering the questions to ensure the appropriate response is provided. It is important that accurate and clear information be provided. You may not know all of the answers. Answer each question to the best of your ability. If we find an answer to be insufficient, the City may contact you to ask for more information. Sometimes, after reviewing the checklist, the City will ask you provide additional studies or information. Commonly requested information includes traffic analysis, site topography, soils studies and tree surveys. UI I Y yr I UIt VVILA Departme f Community Development th�nter Boulevard, Tukwila,WA 988 6300 Sou Telephone: (206) 431-3670 SEPA APPLICATION CHECKLIST FOR STAFF USE.ONLY Planner:: Receipt'Number:> File Number: Cross-reference files: L .Applicant notified:of incomplete application: • Applicant.notified:o complete appl cation: Notice'of application issued A. NAME OF PROJECT/DEVELOPMENT: B. LOCATION OF PROJECT/DEVELOPMENT: (address and accessors parcel number(s)) 4/0.„2 /As Ad NW Q, -t of SE Qic. Quarter. Section: �i Township: -43 G Range: D y (This information may be found on your tax statement) C. PROJECT DESCRIPTION: D. APPLICANT: J U L 2 5 1996 PERMIT CENTER . RMA,:.. City of Tla Central Permit System - Engineering Division 6300 Southcenter Blvd, Suite #100, Tukwila, WA 98188 APIA n # Phone: (206) 433-0179 RE�GEIVEu TY of TUtCWILA UTILITY PERMIT APPLICATIO J L 2 5 1996 ni .i Site Address: 10500 West Marginal Place (Building 9-150) • Name of Project: Duwamish West Riverbank Stabilization PEWIT -CENTER Property Owner: Boeing Defense & Space Group (Terry Bennett) Street Address: P.O. Box 3707, M/S 46-87 Phone No.: 544-2975 City/State/Zip: Seattle, WA 98124-22 Engineer: Boeing Defense & Space Group Street Address: P.O. Box 3707, M/S 46-87 (Terry Bennett) Phone No.: 544-2975 Contractor. City/State/Zip: Seattle, WA 98124-220 Phone No.: Street Address: City/State/Zip: King Cty Assessor Acct #: /,‘4230t/-- 9/50 Contractor's License #: O Channelization/Striping/Signing isREQUESTED f ❑ Curb Cut/Access/Sidewalk ' 0 Fire Loop/Hydr. (main to vault) - No.: _ EJ Flood Zone Control g] Hauling 0 Land Altering cubic yards ❑ Landscape Irrigation O Moving an Oversized Load Est start/end times - Date: ZDE/Nc �l a?yi`9 v Exp. Date: / - / —q 7 O Sewer Main Exten- sa), 0 Private 0 Public orm Drainage Sizes: o Street Use ❑ Water Main Extension ❑Private 0 Public O Water Meter/ Exempt: -No.: Sizes - Deduct ❑ Water Only ❑ O Water Meter/ Permanent - No.: Sizes* : Cllater Meter/ Temporary: - No.: Sizes: Estimated quantity: O Sanitary Side Sewer - No.: Schedule: O Other: 0 Water Name: N/A Street Address: Name: N/A x Street Address: 0 Sewer 0 Metro 0 Standby Phone No.: City/State/Zip: Phone No.: City/State/Zip: IESCRIPTIO 1JECT, O Single -Family Residential ❑ Multiple -Family Dwelling No. of Units: O Commercial/Industrial ❑ Hotel ❑ Motel ❑ Office ❑ Retail ❑ Duplex 0 Apartments O Triplex 0 Condominiums ❑ Warehouse ❑ Manufacturing Other: ❑ Church O School/College/University ❑ Hospital ® Other: Riverbank Stabilizati, 1.) Ij=QRMkV 0 New Building Square Footage; King County Assessor's valuation of existing structures: $ N/A Valuation of work to be done: $ 191, 000 ❑ Remodel/ Addition Square footage of original building space: N/A Square footage of additional building space: N/A { HEREBY CERFIFY TfIT J NAVE READ 'ifft! Applicant/Authorized • ►nt Signature: Flint Name: Terry RPnnPtt E,JGA'TIONAN� I NbW THE .SAME TO: BE TRUE 4i Contact Person (print name): Terry Bennett Address: Date: Phone: 544-2975 Date Application Accepted: Phone: 544-2975 Date Application Expires: • Cont. No. Epic File No. r9(10 " G0210 Fee $ 325 Receipt No. ENVIRONMENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: River Bank Stabilization 2. Name of applicant: The Boeing Company 3. Address and phone number of applicant and contact person: Terry Bennett P.O. Box 3707, Seattle, WA 98124-2207 544-2975 4. Date checklist prepared: June 5, 19816 5. Agency requesting Checklist: City of Tukwila 6. Proposed timing or schedule (including phasing, if applicable): Award rnnstrnrtinn rnntrarr hPfnrp Angncr 1, 1996 Begin work in water Angnct 1, 1996 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. Na 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. None 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 -2- RECEIVED CITY OF TUKWILA J U L 2 5 1996 PERMIT CENTER 1 10. List any government approvals or permits that will be needed for your proposal. Hydraulics Corps of Engineers Section 10 or 404 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. Section E requires a complete description of the objectives and alternatives of your proposal and should not be summarized here. Stabilize the west riverbank of the Duwamish River at seven locations along an approximate 2,300 lineal foot length. Six areas are south 9_ lD9nd Sr_ and one is approximately 400 lineal feet north of S 102nd. The seven areas total approximately 350 lineal feet. The westerly edge of all areas is bordered by a rinder snrfarPd walking trail which is to remain in use. At area 6 itis proposed to move the trail west to maintain the original 8 foot minimum from traiLto top of hank_ 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. North and south of S 102nd St. bridge across the Duwamish River along_the_west bank of the river at marked locations. 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? Yes -3- • TO BE COMPLETED BY APPLICANT Evaluation for Agency Use Only B. ENVIRONMENTAL ELEMENTS 1. Earth a. General descriptio-te (circle one): Flat, rolling, hilly, steep slopes, mountainous, other b. What is the steepest slope on the site (approximate percent slope)? 40 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. Sand,. muck d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Yes, riverbank slumping at areas 5 and 6 e. Describe the purpose, type, and approximate quanti- ties of any filling or grading proposed. Indicate source of fill. Rip -rap for armor and toe rock - 520 CY 6" minus quarry spalls for fill - 453 CY. 1-1/2" gravel under lowest layer of cutting/soil - 27 CY. Soil backfill material - 230 CY, Rip -rap and quarry spalls from local quarries. Soil from local suppliers. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. No g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? N/A -4- • • h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Stabilize bank with quarry spalls covered with rip -rap. 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. Dust, equipment exhaust 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: 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. Duwamish river 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. yes 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. None 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. Yes, entire site 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. No -6- Evaluation for Agency Use Only • Evaluation for b. Ground: 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 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. Storm water on banks will flow into river. -7- • • 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: 4. Plants Check or circle types of site: deciduous tree: alder, evergreen tree: fir, ce shrubs grass pasture crop or grain wet soil plants cattail, skunk cabbage, other water plants: water lily, other types of vegetation vegetation found on the aspen, of ar, pine, other buttercup, bullrush, eelgrass, milfoil, other What kind and amount of vegetation will be removed or altered? Grass, water plants, blackberries, scotchbloom c. List threatened or endangered species known -to be on or near the site. None -8- Evaluation for Agency Use Only 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: Willow cutting, grass 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, ducks, geese mammals: deer, bear, elk, beaver, rabbits, mink fish: bass, salmon, trout, herring, shellfish, other: salmon b. List any threatened or endangered species known to be on or near the site. No, would be fish only c. Is the site part of a migration route? If so, explain. Yes, migratory salmon — d. Proposed measures to preserve or enhance wildlife, if any: -9- 6. Energy and Natural Resources 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. NIA a. • Evaluation for Agency Use Only 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: N/A 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. No 1) Describe special emergency services that might be required. None 2) Proposed measures to reduce or control environ- mental health hazards, if any: -10- • • b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? None Evaluation for Agency Use Only 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. Traffic, construction activity, equipment operation 3) Proposed measures to reduce or control noise impacts, if any: 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? Employee activity center, parking, walking trail b. Has the site been used for agriculture? If so, describe. No c. Describe any structures on the site. Activity Center - adjacent to site west of areas 1 and 2 -11- • d. Will any structures be demolished? If so, what? No e. What is the current zoning classification of the site? mTc/n f. What is the current comprehensive plan designation of the site? MC/II/Shoreline g. If applicable, what is the current shoreline master program designation of the site? Urban h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. Yes, state shoreline i. Approximately how many people would reside or work in the completed project? None j. Approximately how many people would the completed project displace? None k. Proposed measures to avoid or reduce displacement impacts, if any: 1. Proposed measures to ensure the proposal is com- patible with existing and projected land uses and plans, if any: -12- Evaluation for Agency Use Only • • 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? N/A b. Approximately how many units, if any, would be eli- minated? Indicate whether high, middle, or low- income housing. N/A c. Proposed measures to reduce or control housing impacts, if any: N/A 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? N/A b. What views in the immediate vicinity would be altered or obstructed? None c. Proposed measures to reduce or control aesthetic . impacts, if any: -13- • • Evaluation for Agency Use Only 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? None b. Could light or glare from the finished project be a safety hazard or interfere with views? Nn c. What existing off-site sources of light or glare may affect your proposal? None d. Proposed measures to reduce or control light and glare impacts, if any: None 12. Recreation a. What designed and informal recreational oppor- tunities are in the immediate vicinity? Walking trail.. 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: -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. No b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None c. Proposed measures to reduce or control impacts, if any: 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. S 102nd St., East Marginal Way South, West Marginal Way South b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No, 600 ft. c. How many parking spaces would the completed project have? How many would the project eliminate? None, four -15- • • 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). No e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. Nn f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. None g. Proposed measures to reduce or control transpor- tation impacts, if any: 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. No b. Proposed measures to reduce or control direct impacts on public services, if any. -16- Evaluation for Agency Use Only • Evaluation for Agency Use Only 16. Utilities a. Circl utilities currently available at the site: electricity natural gas, water refuse service, telephone, sanitary sewer, septic system, other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water, City of Tukwila Water Dept. C. Signature The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Submitted: PLEASE CONTINUE TO THE NEXT PAGE. • • , TO BE COMPLETED BY APPLICANT Evaluation for Agency Use Only D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (do not use this sheet for project actions) Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not imple- mented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to .water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? N/A Proposed. measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants, ani- mals, fish, or marine life? Large woody debris will be placed on the bank at 3 locations below the ordinary high water mark. Proposed measures to protect or conserve plants, ani- mals, fish, or marine life are: Install woody debris on bank below ordinary high water mark. -18- • • Evaluation for Agency Use Only 3. How would the proposal be likely to deplete energy or natural resources? N/A Proposed measures to protect or conserve energy and natural resourses are: N/A 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? N/A Proposed measures to protect such resources or to avoid or reduce impacts are: 5. How would the proposal be likely to affect land and shoreline use, inclduing whether it would allow or encourage land or shoreline uses incompatible with existing plans? Allow continued use of portions of the existing walking trail and service road. -19- s Evaluation for Agency Use Only Proposed measures to avoid or reduce shoreline and land use impacts area: How does the proposal conform to the Tukwila Shoreline Master Plan? Maintenance of riverbank 6. How would the proposal be likely to increase demands on transportation or public services and utilities? No change Proposed measures to reduce or respond to such demand(s) are: 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the environment. No Conflict -20- • • Evaluation for Agency Use Only . Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? No Proposed measures to avoid or reduce the conflict(s) are: -21- T0' BE COMPLETED BY APPL ICT • 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 stabilize eroding riverbank and preserve walking trail and service road. 2. What are the alternative means of accomplishing these objectives? NnnP 3. Please compare the alternative means and indicate the preferred course of action: -22- Evaluation for Agency Use Only • • 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? No Proposed measures to avoid or reduce the conflict(s) are: -23- •Q n •- ,b,, -o q pain ti .e M S e ° o 0 E.Y.- /-* >. b• Ei 44 ze. t Report Geotechnical Engineering Services West Duwamish Riverbank Stabilization Project JUL.2 5.19 6 ' • Geo Engineers Boeing Military Airplane Company P.O. Box 3707, M/S 46-87 Seattle, Washington 98124 Attention: Mr. Glenn McKinney • Geotechnical, Geoenvironmental and • Geologic Services Report Geotechnical Engineering Services West Duwamish Riverbank Stabilization Project Tukwila, Washington File No. 0120-174-R05 INTRODUCTION This report presents the results of our geotechnical engineering services for the West Duwamish Riverbank Stabilization Project in Tukwila, Washington. The project includes approximately 3,300 linear feet of the west riverbank adjacent to property occupied by the Boeing Company. The site and surrounding features are shown on the Vicinity Map, Figure 1. A detailed plan of the site is shown on the Site Plan, Figure 2. The scope of our services was presented to you in our Project Approach dated August 13, 1993. The services were authorized by your Work Order Request for Job No. 737380, executed August 30, 1993. Our services were performed in general accordance with the Services Agreement between our two firms dated October 10, 1984. We also presented revised scopes of services on October 18, 1993 and on December 6, 1993. We completed portions of the additional services included in the revised scopes; other services described in the revised scopes were not completed, at your request. Our understanding of the project is based on information and plans that you provided, and on our experience. The information includes the following reports: • Report of River Bank Stabilization Study, Phase I, Employees Activity Center Site, Boeing Development Center, Seattle, Washington, dated November 10, 1986, by Dames & Moore. • Report of Phase II River Bank Stabilization Study, Boeing Development Center, Seattle, GeoEngineers. Inc. Washington, dated November 24, 1986, by Dames & Moore. 8410 154th Avenue N.E. Redmond. WA 98052 Telephone (206) 861-6000 Fax (206) 861-66050 SITE CONDITIONS GENERAL The project is located within an alluvial valley approximately six miles south of the Duwamish River discharge into Elliott Bay. The ground surface in the project area and vicinity is generally level, at approximately Elevation 10 feet MSL (Mean Sea Level datum). The level ground extends about 1,000 feet west of the site and a greater distance to the east. The Duwamish River forms an oxbow bend, concave to the west, thought the project area. The west riverbank is not developed in this area except where two bridges cross over the river. The upland area west of the river is developed with a large asphalt concrete paved parking lot in the center and north end of the project area, and a recreation center structure near the south end of the project area. The area immediately adjacent to the riverbank is landscaped. A sand and fine gravel surfaced foot path roughly parallels the top of the west riverbank. The path is very close to the top of the bank in some areas of the project and is separated by more than 20 feet from the bank in other areas. The path is approximately 8 feet wide and is bordered by grass on both sides. We completed an on -land site reconnaissance in September, 1993 and an on -water reconnaissance in November, 1993. No subsurface explorations using power equipment were Boeing Military Aire Company April 15, 1994 Page 3 • completed for this project; however, we did perform shallow hand explorations during our reconnaissance to classify the riverbank materials. Our observations are presented in the following sections of this report. RIVER CHARACTERISTICS The Duwamish River ranges from about 200 feet wide at the south end of the project, to about 400 feet wide at the north end. The water level in the river is affected both by,the river flow from upstream and by tidal influences. We understand that the river flow can range from about 200 cfs (cubic feet per second) to 12,000 cfs. During low flow conditions, the river level will be affected mostly by tidal fluctuation, and during high flow conditions, the river level will be controlled mostly by the flood water from upstream and less by the tidal effects. We understand that the average current velocity of the river is about 5 fps (feet per second) in the project area. The maximum high water level of the river in the project area is reported to be about Elevation 7 feet MSL. The minimum low water elevation is reported to be about Elevation -8 feet MSL. For reference purposes, Elevation 0 feet MSL corresponds to Elevation 6.6 feet MLLW (Mean Lower Low Water datum). MLLW is the datum used for reporting water surface levels on tide charts. SUBSURFACE CONDITIONS Soils Our site reconnaissance and shallow explorations indicate that the riverbank soils range from fine sand with negligible silt to very silty fine sand and sandy silt. Sandy soils are predominant in the upper portion of the riverbank and silty soils are predominant in the lower portion. The consistency of the soil ranges from loose to medium dense or medium stiff. The soils are interlayered in generally discontinuous layers, as is typical of alluvial deposition. The upper several inches of soil typically contains roots and other organic material. The soils exposed on the more moderately inclined river bottom, downslope from the steeper bank, consist of unconsolidated or moderately consolidated fine grained sediments. The sediments are very soft to soft. Essentially no live vegetation is present on the river bottom except for isolated trees that encroach into the river from the upper portion of the riverbank. Isolated large organic debris, consisting mostly of tree stumps and logs, is present on the river bottom. Ground Water We observed evidence of ground water seepage from the riverbank during low water conditions. The evidence consists of localized erosion channels. extending back into the riverbank and areas of dense vegetation. We also observed seepage occurring at isolated locations. _ _G.e.o E n_g i.n e e r s Cate tV..• nInn nnc Boeing Military Airie Company April 15, 1994 Page 4 • The seepage appears to occur below a level about 3 to 4 feet below the top of the riverbank. The rate of seepage is generally slow. RIVERBANK CONDITIONS General The west Duwamish riverbank in the project area ranges from about 8 to 12 feet high above the more moderately inclined river bottom at the toe of the bank. The top of the riverbank is approximately level with the ground adjacent to the bank, or is raised above the adjacent ground by only a small amount. Thus, the riverbank does not form a flood protection levee for the adjacent area. The riverbank slope inclination generally ranges from about 2H:1V (horizontal to vertical) to 1H:1V over most of the project, but becomes nearly vertical locally. The steeper portions of the bank are locations where the bank has eroded and sloughed off. Both recent and older erosion features were observed. The river bottom is more moderately inclined. In the vicinity of the toe of the riverbank, the river bottom is typically inclined at 4H:IV to nearly level. A break in the river bottom slope, roughly corresponding to the low flow channel, is present at some locations. Where this break in slope is present, the river bottom in the low flow channel is inclined more steeply than the adjacent segment of river bottom. Isolated slumps were observed in the river bottom sediments. These slumps typically occurred near the break in slope. The slumps are generally small, with head scarps on the order of about 10 feet wide. The vegetation along the riverbank consists of grass, heavy brush, blackberry brambles, isolated trees and isolated clusters of cat tail reeds. The brush and berry brambles are typically very heavy. The vegetation overhangs the riverbank along much of the project. Where the riverbank has experienced recent erosion and sloughing, the vegetation is often sparse or absent. Portions of the riverbank have been protected with riprap and concrete rubble. The riprap is placed in a systematic manner in some areas and in a more random manner in other areas. The concrete rubble is mostly randomly placed. Metal and other debris was also observed at some locations on the riverbank. A riverbank repair consisting of riprap and geotextile retained soil fill is present at one location along the bank (Station 12+00 to 12+50). Detailed observations of the riverbank conditions are presented in the following section of this report. Current Stability Conditions To provide a basis of reference for identifying the various features and conditions of the riverbank, we established project stationing along the riverbank. The stationing is shown on the Site Plan, Figure 2. c e_� Elk -No 0120-174-R05 Boeing Military Aire a Company April 15, 1994 Page 5 • Portions of the riverbank are moderately inclined, well vegetated and appear to be currently relatively stable. No specific comments are included in this report for those areas that appear to be currently relatively stable, in our opinion. Our observations are presented below for areas of existing or potential instability and/or where other noteworthy features were observed. Station 2+00 to 2+75 and Station 3+50 to 4+10: The riverbanks in these segments are very steep; however, the vegetation is well established and the banks are heavily overgrown. These riverbanks appear to be currently relatively stable. Station 4+10 to 5+40: This is a 130 -foot -wide arcuate area of erosion that has apparently been an active erosion area for several years. The eroding bank is near vertical and is regressing to the west, toward the trail. The trail is currently separated from the bank by about 20 feet. The bank is poorly vegetatedin this area. Station 5+40 to 6+00: This section of the riverbank has been stabilized with riprap, apparently in 1986. The riprapped bank appears to be currently relatively stable. Station 6+00 to 6+30: This 30 -foot -long segment is a small, steep arcuate erosion feature immediately downstream from the root ball of a tree that is established on the riverbank. The trail is currently separated from the bank by more than 20 feet. The bank is moderately vegetated in this area. A repair has apparently been attempted here, as evidenced by geotextile material that is draped over the upper portion of the bank; however, the repair has not been effective. Station 8+60 to 8+90 and Station 9+30 to 9+65: These segments, totalling 65 feet long, are areas with steep arcuate erosion features. The trail is currently separated from the bank by more than 20 feet in the first segment and by about 8 feet in the second segment. The bank is poorly to moderately vegetated in these areas. Station 5+75 to 9+30: Except as noted above, the riverbanks in this segment are very steep; however, the vegetation is well established and the banks are heavily overgrown. These riverbanks appear to be currently relatively stable. Station 12+00 to 12+50: This is an area where the bank has been repaired. The repair consists of riprap on the lower portion of the bank and reinforced soil fill on the upper portion of the bank. The reinforced soil consists of geotextile and geogrid wrapped layers of fill. The n E n o_i._n . pr. r.� • • • . Boeing Military Airplane Company April 15, 1994 Page 6 wrapped layers have branches (live stakes) protruding from between the wraps. We understand that this repair was completed about one year ago. The reinforced soil is slumping severely in the center of the repair. Station 17+60 to 18+10: This segment of the riverbank is moderately inclined and well vegetated; however, the trail is very close to the top of the bank (5 feet or less) along much of the segment. The trail is about 8 feet wide and separated from the paved parking lot to the west by a 3 -foot -wide strip of grass. Station 20+40 to 21+50: The riverbank in this segment is very steep; however, the vegetation is well established at the top of the bank. This riverbank appears to be currently relatively stable. Station 25+45 to 25+60: This 15 -foot -long segment has a 4 -foot -high near vertical slope at the top of a more moderately sloping bank. The bank is poorly to moderately vegetated in this area. The trail is about 8 feet from the near vertical bank. • Boeing Military Airplane Company April 15, 1994 - Page 7 Station 27+50 to 30+60: The riverbank in this segment is very steep; however, the vegetation is well established at the top of the bank. This riverbank appears to be currently relatively stable. Station 31+00 to 32+90: The riverbank along this segment is near vertical and ranges from 8 to 9 feet high. The bank is moderately to well vegetated. In our opinion, the riverbank appears to be currently relatively stable. The trail is about 6 to 9 feet from the top of the bank. The river bottom is nearly level and very broad at the toe of this riverbank segment. We observed evidence of instability in the river bottom in this area. CONCLUSIONS AND RECOMMENDATIONS GENERAL On the basis of our evaluation, we recommend that certain segments of the west Duwamish riverbank be stabilized. In other areas of the project, we recommend that the trail be relocated away from the riverbank. Other segments of the riverbank should be monitored and may, or may not, require future mitigation. Our recommendations are based on our evaluation of the current conditions of the riverbank, a comparison of the current riverbank conditions with the conditions reported in the riverbank evaluation completed in 1986, and our understanding of the riverbank erosion process. These considerations are discussed further in the following sections of the report. RIVERBANK EROSION PROCESS In our opinion, riverbank erosion at this site mostly results from seepage of water out of the sandy soils of the banks, and to lesser extent, results from scour by the water flowing laterally across the face of the bank and from wave action. Because of tidal fluctuations, the water level in the river cycles through two daily highs and lows that result in twice -a -day inflow and outflow of ground water in the riverbank. The exfiltration of water from the riverbank is essentially a rapid drawdown condition. The repeated cycles of rapid drawdown progressively erode soil from the bank, and the continued loss of soil progressively weakens the bank. The effects are cumulative, and when sufficiently weakened, a portion of the bank fails. The occurrence of a bank failure event is generally followed by a period of relative stability, until the progressive loss of soil again induces a failure. In our opinion, individual failures are generally localized, and typically involve a thickness of the riverbank measuring in the 1- to 2 -foot -thick range. The intervening period of relative stability between failure events may be in the range of 5 to 20 years. Individual bank erosion features are locally Larger, and locally smaller. The extent and thickness of a failure are probably the result of local variations in the subsurface conditions, and possibly the result of upslope sources of ground water that exacerbate the tidal drawdown condition. Boeing Military Airpliat Company April 15, 1994 Page 8 Because individual failure events occur somewhat randomly and are separated by many years, it is understandable that observations made at different times will result in different classifications of the bank stability conditions. This is the case, to some degree, with the conclusions developed during the riverbank stability evaluation completed in 1986 and the conclusions developed during the current study. For this reason, some areas recommended for repair in 1986 are not now being recommended for stabilization. Conversely, the current study has identified other areas where stabilization is now being recommended, where it was not previously recommended. RIVERBANK STABILIZATION PRIORITIES Segments Recommended for Stabilization We recommend that the riverbank in areas of presently active erosion 'be repaired, especially where the erosion threatens to undercut the bank. We recommend that the riverbank be repaired in the following segments of the project: • Station 4+10 to 5+40 (130 feet) • Station 6+00 to 6+30 (30 feet) • Station 8+60 to 8+90 (30 feet) • Station 9+30 to 9+65 (35 feet) • Station 25+45 to 25+60 (15 feet) The recommended repair scheme is discussed in the Stabilization Recommendation section of this report. We also recommend that the existing repair between Station 12+00 and 12+50 be improved. We recommend that additional riprap be placed over the existing repair to help reduce future erosion of the bank soils and slumping of the existing repair. Because the trail is close to the top of the bank in this area, it may also be desirable to relocate the trail away from the bank. The total lineal footage of the segments where riverbank stabilization is recommended measures 290 feet. Segments Where Trail Should Be Relocated The existing trail is located very close to the top of the riverbank in several areas of the project. Our evaluation of the riverbanks in these areas suggests that the banks are not presently eroding excessively and do not presently warrant repairs, except for the improvement of the existing repair at Station 12+00 to 12+50 . However, the natural riverbank erosion process could result in future erosion and sloughing that could encroach on the trail in these areas, in our opinion. Therefore, we recommend that the trail be relocated 'away from the riverbank to provide a buffer area between the trail and the top of the riverbank. n7 --.E • Boeing Military Airline Company April 15, 1994 Page 9 • We recommend that the trail be relocated away from the riverbank in the following areas. • Station 12+00 to 12+50 (50 feet) • Station 16+30 to 17+30 (100 feet) • Station 17+60 to 18+10 (50 feet) The segment from Station 16+30 to 17+30 was identified in the riverbank stability evaluation completed in 1986 as an area requiring stabilization. However, in our opinion, the riverbank is presently relatively stable in this area and therefore does not require repair. The total lineal footage of the segments where the trail should be relocated is 200 feet. Segments That Should Be Monitored Certain riverbank areas are presently relatively steep and/or were identified in the riverbank stability evaluation completed in 1986 as requiring repairs. In our opinion, these areas appear to be performing moderately well at the present time and do not warrant repair. However, the natural riverbank erosion process could result in future erosion and sloughing that could require repairs in these areas. We recommend that these areas of the riverbank be monitored. If erosion and sloughing occurs in the future, the necessity for repairs should be re-evaluated at that time. We recommend that the following areas of the riverbank be monitored. • Station 2+00 to 2+75 (75 feet) • Station 3+50 to 4+10 (60 feet) • Station 5+75 to 9+30, except where repairs are recommended (295 feet) • Station 13+55 to 14+00 (45 feet) • Station 15+25 to 16+30 (105 feet) • Station 17+30 to 17+60 (30 feet) • Station 20+40 to 21+50 (110 feet) • Station 27+50 to 30+60 (310 feet) • Station 31+00 to 32+90 (190 feet) The total lineal footage of these segments is 1220 feet. STABILIZATION RECOMMENDATION General We considered several alternative riverbank stabilization schemes, including flattening the riverbank slopes, constructing riprap slope revetments, and shoreline bulkheads. We reviewed the alternatives with you, and we mutually agree that riprap:slope revetments are the preferred stabilization alternative. On this basis, we developed the recommended riverbank repair scheme G e o E n e i n e e r c --- C:Y. hT. nWelt • Boeing Military Airplane Company April 15, 1994 Page 10 shown on the Stabilization Detail, Figure 3. This repair scheme is similar to a riverbank stabilization project recently completed on the east bank of the Duwamish River, upstream of the current project. The repair scheme combines riprap erosion protection in the lower portion of the riverbank, and terraced, vegetated slopes in the upper portion of the riverbank. The riprap is extended up to Elevation 7 feet MSL, approximately the high water level of the river. Long-term stabilization of the upper portion of the bank will be accomplished through the development of a network of deep roots from vegetation specifically selected for this purpose. The upper terraces will also allow for safe pedestrian access to the riverbank. We recommend that the riverbank repair be constructed without cutting into the existing bank materials except at the ends of each repair segment where the repair is tapered into the adjacent bank. The repairs should be constructed as fill above the existing riverbank materials. At the ends of each repair segment, we recommend that the transition of the repair into the native bank be made as smooth as possible to help minimize any erosion of the native bank due to water turbulence. As mentioned previously, a break in slope is present in the river bottom at some locations, roughly corresponding to the low flow channel. Isolated slumps are present in the river bottom near this break in slope. It is important that adequate separation be maintained between the toe of the rock fill shown in Figure 3 and the break in slope. Our review of the river bottom cross sections developed by Dames & Moore indicates that adequate separation will be achieved at most locations. However, there might be some locations where field modifications in the stabilization detail shown in Figure 3 will be necessary to provide this separation. Clearing and Site Preparation Prior to constructing the repairs, all trees, brush and berry brambles should be removed together with their main root balls. During the site preparation, any existing riprap or concrete rubble in the repair areas can be separated and stockpiled for reuse in the final repair. Any metal or other debris encountered in the repair areas should be removed from the site. Voids left by clearing and stripping should be backfilled with 11h -inch -minus gravel, as specified below. Subgrade preparation should consist of smoothing the cleared subgrade for placement of the geotextile fabric and subsequent rock and soil material. The surface should not have protruding roots or branches that could tear the fabric. Geotextile Filter Fabric We recommend that the coarse gravel and rock material in the upper portion of the repair be separated from the relatively fine grained riverbank material with a non -woven geotextile filter fabric, such as Mirafi 140N, or similar material. The purpose of the filter fabric is to help Boeing Military Arne Company `.-) April 15, 1994 Page 11 prevent erosion of the riverbank material into the coarse gravel and rock. The filter fabric should be placed over the upper, steep riverbank slope. The filter fabric should not be placed on the flatter river bottom except where water seepage is visible. Rock Material We recommend that the riprap consist of toe rock in the 2- to 3 -foot -diameter size range and armor rock in the 1- to 2 -foot -diameter size range. The facing rock for the upper slope terraces should be 2 -foot -diameter rock. The rock should be highly durable and it should not be fractured, laminated, porous or otherwise physically weakened such that it's durability could be affected. The bedding rock should consist of 6 -inch -minus quarry spalls. As shown on Figure 3, the bedding rock should be separated from the soil in the upper vegetated terraces by a 4 -inch -thick layer of 11/2 -inch -minus gravel. This gravel should be well graded, similar to a pavement base course material. Rock Placement All bedding rock and riprap should be placed in a controlled manner by power equipment. The lowest course of riprap (toe rock) should be pushed into the river bottom sediments with the weight of the power equipment. The subsequent riprap (armor rock) and bedding rock should be placed and built-up concurrently. The face of the riprap slope should be inclined at 1 M H:1 V. The riprap should be placed in such a manner that all large rocks shall be in essential contact with each other. Smaller rock should not be wedged into the riprap to achieve contact between individual large rocks. Voids between individual rocks should not be large enough to allow the bedding rock to be washed out through the hole. Any such voids should be chinked with smaller rock from 'behind or below to plug the hole. Local surface irregularities of the riprap shall not vary from the planned slope by more than one foot measured at right angles to the slope face. The armor rock should be underlain by a minimum thickness of 6 inches of bedding rock. The bedding rock need not be mechanically compacted; however, it should be smoothed during placement to in -fill any voids, especially around the riprap. As shown on the Stabilization Detail, Figure 3, the armor rock should extend up to Elevation 7 feet MSL. The bedding rock should extend to within 4 inches of Elevation 7 feet MSL. The upper 4 inches of material behind the armor rock should consist of 11/2 -inch -minus gravel. This gravel need not be mechanically compacted; however, it should be smoothed during placement. The bedding rock and riprap will be placed on very soft to soft fine-grained soils. There is some possibility that slope movements could be induced in these soils if the rock is placed over a short period of time. Depending on local soil conditions and on the thickness of rock to be Ge o Enn 17e r c Boeing Military Arne Company April 15, 1994 Page 12 • placed, it may be advisable to stage rock placement, that is to place the rock in lifts with adequate time between each lift to allow the underlying soils to gain strength. The need for staged rock placement can best be determined during construction, in our opinion. Vegetated Slope The riverbank repair above Elevation 7 feet MSL should consist of vegetated terraces. The terraces should be about 18 inches thick. Each terrace should be faced with a single course of 2 -foot -diameter riprap (facing rock) to help form and retain the terrace. The soil in the vegetated terrace layers should consist of topsoil. The 18 -inch -thick layer should be constructed in three lifts; 7 -inch -thick lower and upper lifts of topsoil, and a 4 -inch - thick center lift of sapling cutting "Live Stakes" mixed with topsoil. The live stake sapling cuttings should have a maximum diameter of 3 inches and may be up to 6 feet long. The cuttings should be extended out from the topsoil, between and above the facing rocks. Each 18 -inch -thick terrace layer should be underlain be a geotextile fabric that extends from the riverbank out to the face of the rock forming the terrace. Additionally, the facing rock should be backed by geotextile fabric to help retain the topsoil between the facing rocks. We understand that King County recommends using a geotextile fabric consisting of coir material for this application. Coir fabric consists of woven coconut fiber that is biodegradable. We agree that coir material is suitable for this application provided that the live stakes are properly installed and take root prior to degradation of the fabric. We recommend that a landscaping professional be consulted regarding the type of live stake saplings to be used, and placement methods, as well as regarding suitable soil amendments for the topsoil. We also recommend that the landscaping professional be made aware of the damage to the existing trees along the riverbank that is apparently caused by beavers. TRAIL RELOCATION We recommend that the trail be relocated away from the top of the riverbank wherever the trail is within about 2 feet of the existing top of bank. This is intended to move the trail out of the zone of potential failure that may occur even in areas where the riverbanks are currently considered to be relatively stable, in our opinion. MONITORING PROGRAM We recommend that the riverbank monitoring program consist of periodic close inspections of the areas of riverbank repair and the additional areas identified for monitoring in this report. We understand that Boeing personnel currently perform such a monitoring program. The monitoring should attempt to locate any areas of new erosion or progressive failure. Conditions e o E n g i n e e r s ra �i min », nnc Boeing Military Ai lane Company April 15, 1994 Page 13 to monitor for include any cracking of the ground surface near to the riverbanks, changes in the inclination of the trees lining the riverbanks, changes in vegetation density, or loss of ground on the riverbanks. LIMITATIONS We have prepared this report for use by Boeing Military Airplane Company, and other members of the project team involved in the West Duwamish Riverbank Stabilization project. The conclusions and recommendations in this report should be applied in their entirety. The data and report should be provided to prospective contractors for bidding or estimating purposes; but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. If there are any changes in the grades, locations, configurations or types of construction planned, the conclusions and recommendations presented in this report might not be fully applicable. If such changes are made, we should be given the opportunity to review our conclusions and recommendations and to provide written modification or verification, as appropriate. When the design is finalized, we recommend that we be given the opportunity to review those portions of the specifications and drawings that relate to geotechnical considerations to see that our recommendations have been interpreted and implemented as intended. Some contingency for unanticipated conditions should be included in the project budget and schedule. We recommend that sufficient monitoring, testing and consultation be provided by our firm during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether construction activities comply with the contract plans and specifications. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in this area at the time the report was prepared. No warranty or other conditions, express or implied, should be understood. G r n F n 4 O ► Boeing Military Airp'Iane Company April 15, 1994 Page 14 We appreciate the opportunity to provide geotechnical services on this interesting project. If there are any questions concerning this report or if we can provide additional services, please call. I EXPIRES APRIL 3, 1995 TAT:JBT:cme Document ID: 0120174.R Attachments Three copies submitted Yours very truly, GeoEngineers, Inc. cc: Mr. Gary Schulz (2 copies) City of Tukwila Department of Community Development 6300 Southcenter Boulevard Tukwila, WA 98188 Mr. Andy Levesque (1 copy) King County Dept. of Public Works SWM Division 700 - 5th Ave., Ste 2200 Seattle, WA 98104 Gen F_n i n r e r c Thomas A. Tobin, P.E. Geotechnical Engineer S James B. Thompson, P.E. Principal r:,. .I.. nlfn . nnC NYON MO ST !ald4ols" .;:rtR PK ELP4GROvE !SeuTHE4m : I ?21 I \(e ryni ,nny. BOEING IELD KENYON BOEING PGD suuiviN L FS coiamli I100� ST S DIRECTOR CLOVERMLE 5 TRENTON S 9310 ST sird sr 5 ioisf I Ca S MORO SY COOPER s oCTOR 116TH/ ST 4 - 124Th Scale in Feet Reproduced with permission granted by THOMAS BROS. MAPS. This map is copyrighted by THOMAS BROS. MAPS. It is unlawful to copy or reproduce all or any part thereof. whether for personal use or resale. without permission. FIGURE 1 ,eijl/ (;eo, Engineers T�. (1,41 -__ A4p4_. • SITE PLAN FIGURE 2 .wn No 01:`!1- 174-R0'. _ Rev Tale 01!03!94 ELEVATION (FEET) 15 - Trail E -tet• -- Vegetated Terraces (See Note 1 and Detail) 2 -Foot Diameter Facing Rock Above El = 7.0 Feet (See Detail) El 7.0 Feet - Upper Limit of Armor Rock 10- -10 - Coir Geotextile Fabric (See Note 2) 4 -Inch Layer of 1 1/2 -Inch Minus Gravel Geotextile Filter Fabric Existing Riverbank 18" 1 3/4 1- to 2 -Foot Diameter Armor Rock Below El = 7.0 Feet 2- to 3 -Foot Diameter Toe Rock 6 -Inch Minus Quarry Spalls (Minimum 6 -Inch Thickness Below Armor Rock) Livestake Saplings Vegetated Terraces L-18" �I DETAIL NO SCALE 2 -Foot Diameter Facing Rock Coir Geotextile Fabric (See Note 2) HORIZONTAL SCALE: 1' _ 5. Notes: 1. Vegetated terraces consist of 18 -inch -thick soil layers with live stake' sapling cuttings. Each terrace is faced with 2 -foot diameter facing rock. Overall inclination of the terraces is approximately 2H:1V. 2. Coir Geotextile Fabric below each vegetated terrace layer extending from the riverbank to the front of the facing rock. Additional Coir Geotextile Fabric behind the facing rock. -15 10 -5 0 -5 -10 ELEVATION (FEET) Geoo Engineers STABILIZATION DETAIL FIGURE 3 .Park l\ '\\1 \ - ' 1 \ 1. I, ' .:V ill . ��. :.lit Tanks.._ ' • Z'\ `, moi ■ s py '' 7...z. \\s‘ BM '' \ . (• � "\ If\ s A l�-\ LAT 4-7 3 0 36 �_� \� s,LON 122° f;'t132" ` �j�' SITE- .s.IO2nd\ 1 n Parking Area To .II • J olf Club 1 1 7 Southern 'Hi igts (DES MOINES) d 1578 IV NE SCALE 1:24000 0 553 \122°17'30" 1-1-7° 1.7° 30' l.6 Ml. TO INTERSTATE 5 1 MILE T - 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET VICINI MAP SCALE 1"=24000 5 • • TACOMA 25 M1:‘ oLiECEIVED CITY OF TUKWILA JUL 251996 PERMIT CENTER uNrER.nw• 55r PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUF PAGE: 1 OF 17 DATE: 06.14.96 • FACE 9171 N • \1 S 102ND ST. N88'51'51"W [AGE80Fi1 p, I r \ 23+02.79 BASEUNE 1 I --7--0F171PK NAIL WITH I I FAGE CONTROL FLASHER L\ J: \ t 1 1 13+37.71 BASELINE \ / 1 I PK NAIL WITH CONTROL FLASHER L _ _ I \ �� 1 / \ I 9+07.99 BASEUNE lEAGE 6 OF 1J HUB & TACK SCALE: NO SCALE 5+79.63 BASEUNE I REBAR WITH RED LAS E 5 OF 1 J CONTROL CAP ____ 'GE 4 OF 171 2+00.00 BASELINE PK NAIL WITH CONTROL FLASHER r 0+00 BASEUNE HUB & TACK II PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP QATE -06 14:96= 1+52 2+62.5 82.5' 12.8 REMOVE 14" WILLOW 12.6 16"LOW 12" GATED 12" STEWIPE ' I.E. = 4.87 P ATH C 13.4 5 0 c c 0 c 2+00 BASELIN PK NAIL WITH CONTROL FLASH 12.4 c 5 13.1 12" 13.6 WILLOW 13.1 12" WILLOW LIMIT OF GRADING >}rte 135 13.5 5.10 OHW 4.24 MHW FOR VEGETATED GEOGRID CONSTRUCTION DETAILS, SEE SHEET LS500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 PLAN - AREA 1 SCALE: 1" =20' 14.3 CONTOUR INTERVAL = 1 DATUM: USGS MSL ,42 mem �///l���AM y/AW�VAW •ice :�_�_.�i/�, ��.A. ,, IXAWA fro rwarrAwanr amirdommuswilk 1//t///`iA I lllIMIN/LAS/� ♦i ♦. If 11110 ��if* OR�. 11111I11hIW 1CKSS.♦4 �11UIU//!//-/1 '4111/111 _____ � 4 A :Ii1111G1�►/_/E i1\\MISWIII \\44�>QW!r IMAIMII1IW 4% . -..--.Axii‘,;,,,,,t7.4%.04.,,o II/ �SII 1 'a • L✓ 14.4 raso II� 10514 —8.0 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON AP PL BY: BOEING DEFENSE & SPACE GROUF PAGE: 3-0F--17-- . -.- - -- DATE: 06:-14:96_ • 5+79.63 BASELINE REBAR WITH RED CONTROL CAP 3+53.25 X 12.9 TOP OF BANK 13.1 (`fln N cl`i C80 C5003.1 3+31.5 13.2 C80 c51t4 x 13.4 97 24" COTTONWOOD 5.10 OHW 4.24 MHW PLA\ AREA 2 12.7 SCALE: 1" =20' CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRIO CONSTRUCTION SEE SHEET LS500 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUF -PAGE: -_4 OFA_ -17- _ -DATE: 06.1-4.96 _ 9+07.99 BASELINE SET HUB'& TACK 13. 13.3 • GENERAL NOTE: 1. 100 YR FLOOD = EL+8.3 + —9.9 X 12" WILLOW —8.4 5.10 OHW —4.8 x 4.24 MHW 0 ASPH 13.7 co —8.3 TOP OF BANK TOP OF BANK 13.3 X 12.5 5+79.63 BASELINE REBAR WITH RED CONTROL CAP 13.1X x —10.0 2+00.00 BASELINE PK NAIL WITH ---CONTROL-FLASHER C8 Q '0 PATH 11.1 MHHW TOP OF BANK 12" WILLOW 13.2 13.1 PJaN — AREA 3 SCALE: 1 ' =20' CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRID CONSTRUCTION DETAIL, SEE SHEET L5500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: -- 5 OF 17- DATE:- -06.1-4:96 4.24 MHW 5.10 OHW TOP OF BANK NEW TOP OF BANK X -8.7 9+71.60 tk• 10.5 10.4 9+07.99 BASELINE HUB & TACK P _A\ SCALE: 1" =20' AKA 4 TOP OF BANK 75' 5+79.63 BASELINE REBAR WITH RED CONTROL CAP CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRID CONSTRUCTION DETAIL SEE SHEET LS500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 -4.6 X PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNT( OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP GE:::_16 _OF - 17 • CONCRETE PIPE WITH CAP I.E.=1.19 X -5.3 -8.8 x X X -8.6 x -5.6 " ' TOP OF BANK—\ 3.8'`'I�1'�•%�•���� IP- fit1;42ZINIZA.MVALOAN7 , �', �1 ��a:�a��.l:��`AP', !�H ezoq='' 4 9.8 "OtaviverI-1447"e" A AII ' �A+2,�� ��Ak.....,. fir NEW' TOP OF BANK TOP OF BANK 9.9 4.24 MHW 5.10 OHW TOP OF BANK 10+82.60 Ci 12" WI LLO W 13+37.71 BASELINE PK NAIL WTH CONTROL FLASHER 10+67.60 10+36.60 9+07.99 BASELINE HUB & TACK P _AN AREA 5 SCALE: 1'1=20' CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRID CONSTRUCTION DETAIL SEE SHEET LS500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 FOR PATH REL0CA11ON DETAILS SEE SHEET LS80 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUF - PAGE 7= OF --1 --- =DATE - TOP OF BANK 23+02.79 BASELINE PK NAIL WITH 11. CONTROL FLASHER 10. 1.4 -3.0 1.1 X -3.2 - 3.8 -2.8 X -3.9 X 2_ MSL 1.0 4.24 MHW -5.10 OHW 12.0 TOP OF BANK 13+67.20 1.2 13+37.71 BASELINE PK NAIL WITH CONTROL FLASHER 10.9 9+07.99 BASELINE HUB & TACK PLAN - AREA 6 SCALE: 1" =20' CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRID CONSTRUCTION DETAIL SEE SHEET LS500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 FOR PATH RELOCATION DETAILS SEE SHEET LS80 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE:._ _8 OF _17_. _ _ _.___ DATE:_ 06._14.96._ 23+02.79 BASELINE PK NAIL WITH CONTROL FLASHER • -8.9 6" DECIDUOUS TOP OF BANK 10.6 4.2 7.8 9.9 -9.8 X -7.9 X X -12.0 x -11.8 X -11.7 0 -7.1 �2 4.7 7�-5.10 OHW 0.0 4.24 MHW •3 11.5 ARMOR ROCKS 11.0 1.5 16" WILLOW 22+77.10 C' 799' 22+66.60 22+57.30 X -11.E x -12.0 -11.0 13+37.71 BASELINE PK NAIL WITH CONTROL FLASHER PJaN - AREA 7 SCALE: 1" =20' CONTOUR INTERVAL = 1 DATUM: USGS MSL FOR VEGETATED GEOGRID CONSTRUCTION DETAIL SEE SHEET LS500 FOR SEEDED AREAS DETAILS SEE SHEET LS500 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 9. OF 1.7. DATE: 06.14.96_ - -------------- ------ _ UPSTREAM - SEE SECTION A DOWNSTREAM - SEE SECTION B -1Z EL +8.3 wil- _ V APPROX HIGH_WATER LEVEL 2'-b�MIN,_T'^ SZ 0 -HW = EL +5.10 14 13 12 11 10 9 8 7 6 R EAN SEA LIVE EXISTING BOTTO V MLLW SECTION - AREA 1 SCALE: 1"=4' HORIZ 1"=4' VERT APPROXIMATE LIMITS _ _ OF EXCAVATION 1 V 1 CSO 9500 2 1 0 -1 - 2 - 3 - 4 -5 - 6 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 10 OF 17 DATE: 06.14.96 --------------------------------- UPSTREAM - SEE SEC11ON F DOWNSTREAM - SEE SECTION G ---------- EXISTING BANK -------------------------------------- 100.xR-FLO D------- = EL +8.3 V APPROX HIGH WATER LEVEL OHW=EL+5.10 _QUAR Y _ SPALLS PROPOSED BANK _APPROXIMATE LIMITS _ _ _ _ _ _ OF EXCAVATION SECTIO \ -AREA 2 SCALE: 1"=4' HORIZ C80 C500 1" =4' VERT _ .� MEAN SEA LEVEL _ V MLLW __ __ __ 14 13 '12 11 10 9 8 7 6 3 2 1 0 - 1 - 2 -3 -4 - 5 06 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 11 OF 17 DATE: 06.14.96 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 -1 -2 3 -4 -5 6 --�� --------------------------------- --__-----_-_- ----UPSTREAM - SEE SECTION A DOWNSTREAM - SEE SECTION B --------------100 YR_ELOOD------- y = EL +8.3 V APPROX HIGH WATER LEVEL SZ OHW = EL +5.10 --- EXISTING BANK PI -0OTE _14A -N -R ------------ S7 MEAN SEA LEVEL TYP APPROXIMATE LIMITS OF EXCAVATION M SECTION - AREA 3 SCALE: 1" =4' HORIZ 1" =4' VERT 1 v 1 C81 C501 6 VMLLW • PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 12 OF 17 DATE: 06.14.96 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 - 1 - 2 -3 - 4 - 5 6 4 2'-0" MIN TYP Q 100 YR FLOOD=EL +8.3 UPSTREAM - SEE SECTION A sz APPROX HIGH WATER LEVEL DOWNSTREAM - SEE SECTION 8 ---_-----_- Q-OHW=EL+5.10_ 47.7 PROPOSED BANK ARMOR N - - - - -ROC- APPROXIMATE LIMITS OF EXCAVATION O'-6" MIN TYP - SECTION -AEA 4 SCALE: 1"=4' V 1 C82 C502 TYP- ----------.- PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 13 OF 17 DATE: 06.14.96 rte``` -• - DOWNSTREAM - SEE SECTION F APPROX HIGH WATER LEVEL _ 4"GRAVEL MIN EXISTING BANK QUARRY ---------SPALLS - --- EXIST 18 DIA CONC PIPE) EXTEND CAP --TO-DAYLIGHT-AT- - SAME SLOPE -APPROXIMATE LIMITS- ------OF-EXCAVATION-----Y-- - MILLW--------PALLS SECTION - AREA 5 SCALE: 1" =4' (C C82 C502 14 13 X12 11 10 9 8 7 6 3 2 1 0 - 1 - 2 -3 - 4 - 5 6 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 14 OF 17 DATE: 06.14.96 - - -- 14 13 ,12 11 UPSTREAM — SEE SECTION A 10 DOWNSTREAM — SEE SECTION B Q 100 YR FLOOD=EL +8.3 9 8 ____________-__--_-__-__-__-__S APPROX HIGH WATER LEVEL ___ PROPOSED BANK 7 QUARRY -—SPALtS ---------------- EXISTING BANK Q OHW=EL +5.10 6 5 3 - 2 — iut APPROXIMATE LIMITS 1 -'--__ _--_ .Q MEAN SEA LEVEL_—__—_ 0 -------------------------------------------------- --~= ------ —2 ---= = �-- -3 ------------- -4 -5 = MILLW -6 SECTIO\ - AREA 6 SCALE: 1" =4' HORIZ 1" =4' VERT C83 C503 PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE Sc SPACE GROUP PAGE: 15 OF 17 DATE: 06.14.96 � II EXISTING BANK 7 6 OHW=EL +5_10 - - _ _ • 3 2 1 p MEAN SEA LEVEL____r -------- -1 -2 ----- -3 - ����------- -4 -- - =•_ --- -5 v MILLw --- - ----------=---------- SECTION - AREA 7 SCALE: 17=4' HORIZ 1"=4' VERT C8310503 6 9, PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 16 OF 17 DATE: 06.14.96 EXISTING/ RELOCATED CINDER JOGGING TRAIL VARIES SEE PLAN RESTORE LAWN AND REPAIR/ADJUST IRRIGATION IN THIS AREA (TYPICAL). INSTALL TOPSOIL PER TOP OF SLOPE=TOP OF VEGETATED GEOGRID .5 LSf00 LS00 LIVE CUTTINGS/BRUSH LAYERING (TYP.) SEE COIR GEOTEXTILE FABRIC BRUSH LAYERING J�1-5500 PLANTING DETAIL • RIP -RAP SLOPE PROTECTION, SEE SHEETS C80-83 & C500-503 ORDINARY HIGH WATER MARK NATIVE RIVERBANK SOILS SOIL BACKFILL MATERIAL TOP OF RIP-RAP=TOE OF VEGETATED GEOGRID (ELEV.=7.0) r-tk VEGETATED GEOGRID TYPICAL SECTION ��� NOT PD SCALE z4CDEf1.DWC 7-- RIVERBED PROPOSAL: RIVERBANK STABILIZATION AT 7 LOCATIONS IN: DUWAMISH RIVER AT: TUKWILA, WA COUNTY OF: KING STATE: WASHINGTON APPL BY: BOEING DEFENSE & SPACE GROUP PAGE: 17 OF 17 DATE: 06.14.96