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HomeMy WebLinkAboutPermit PL15-0027 - THOMAS BANNISTER - GREEN RIVER BANK REPAIR CHECKLISTSEPA CHECKLIST Parent Project: PL15-0027 ISSUED DNS This File: E15-0007 r City of Tukwila Jim Haggerton, Mayor Department of Community Development Jack Pace, Director DETERMINATION OF NON -SIGNIFICANCE (DNS) File Number: E15-0007 Applied: June 24, 2015 Issue Date: August 17, 2015 Applicant: Thomas Bannister, GeoEngineers Lead Agency: City of Tukwila Description of Proposal: The current proposal is to install a subsurface drainage system and restore an eroded bank on the west bank of the Green River at 14900 Interurban Ave. South. Address: Parcel Number: 14900 Interurban Ave. South, Tukwila, WA 3597000006 This notice is to confirm the decision reached by Tukwila's SEPA Official to issue a Determination of Non - significance (DNS) for the above project based on the environmental checklist and the underlying permit application. 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. Project materials including the application, any staff reports, and other studies related to the permits are available Monday through Friday 8:30 a.m. - 5:00 p.m. for inspection at Tukwila Department of Community Development 6300 Southcenter Blvd., Suite 100, Tukwila, WA 98188. The project planner is Valerie Lonneman, who may be contacted at (206) 433-7140 for further information. This DNS is issued under WAC 197-11-340(2). Comments must be submitted by August 31, 2015. The lead agency will not act on this proposal for 14 days from the date below. a`/Jack Pace, Responsible Official Date City of Tukwila 6300 Southcenter Blvd. Tukwila, WA 98188 (206) 431-3670 The decision is appealable to the Superior Court pursuant to the Judicial Review of Land Use Decisions, Revised Code of Washington (RCW 36.70C). Any appeal shall be linked to a specific governmental action. The State Environmental Policy Act is not intended to create a cause of action unrelated to a specific governmental action. Appeals of environmental determinations shall be commenced within the time period to appeal the governmental action that is subject to environmental review. (RCW 43.21C.075) Cc: Thomas Bannister, GeoEngineers Kurn Schneider, Owner Karen Walter, Muckleshoot Tribe Washington Department of Fish and Wildlife State Department of Ecology, SEPA Division King County Assessor 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206-431-3670 • Fax 206-431-3665 /- \ City of Tukwila Jinz Haggerton, Mayor Department of Community Development Jack Pace, Director FINAL STAFF EVALUATION FOR ENVIRONMENTAL CHECKLIST File No: E15-0007 I. SUMMARY OF PROPOSED ACTION The current proposal is to install a subsurface drainage system and restore an eroded bank on the west bank of the Green River at 14900 Interurban Ave. South (APN#3597000006). II. GENERAL INFORMATION Project Name: Green River Bank Erosion Repair Applicant: Thomas Bannister, GeoEngineers Location: 14900 Interurban Ave. South, Tukwila, WA Zoning: Regional Commercial Mixed Use (RCM) Comprehensive Plan Designation: RCM The following information was considered as part of review of this application. 1. ESA Screening Checklist and SEPA Checklist dated May 18, 2015, revised July 31, 2015. 2. Site Plan, Cross -Section and Drain Details, Details, prepared by GeoEngineers. 3. Revised Analysis and Design Report dated July 30, 2015, prepared by GeoEngineers. NOTE: Technical reports and attachments referenced above may not be attached to all copies of this decision. Copies of exhibits, reports, attachments, or other documents maybe reviewed and/or obtained by contacting Valerie Lonneman, Assistant Planner, 6300 Southcenter Boulevard, Tukwila, Washington, 98188, by phone at 206-433-7140. 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206-431-3670 • Fax: 206-431-3665 III. BACKGROUND/PROPOSAL The proposed project is to install a subsurface drainage system and restore an eroded bank on the west bank of the Green River at 14900 Interurban Ave. South (APN#3597000006). The parcel is generally flat and not leveed. The project will receive Shoreline Substantial Development permit and SEPA (State Environmental Policy Act) determinations. The entire project site is within the 200 foot shoreline jurisdiction of the Green River and the work will be performed entirely within the 100 foot river buffer. Work will not occur water ward of the Ordinary High Water Mark (OHWM) as no evidence of toe erosion nor scour have been found on site. The project design statement sates that the proposed work will mitigate for the ongoing bank sloughing and address potential future drawdown failures, which are believed to be the primary cause of bank sloughing at that location. A detailed description of the riverbank drainage system from the Revised Analysis and Design Report states "the project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and native soil." IV. REVIEW OF THE ENVIRONMENTAL CHECKLIST The following lists the elements contained within the Environmental Checklist submitted for the proposed project. The numbers in the staff evaluation correspond to the numbers in the Environmental Checklist. If staff concurs with the applicant's response, this is so stated. If the response to a particular item in the checklist is found to be inadequate or clarification is needed, there is additional staff comment and evaluation. A. BACKGROUND: 1-4—Concur with checklist. 5—The construction will follow issuance of SEPA determination and after obtaining all required permits from the City of Tukwila or other agencies. 6-10—Concur with checklist. 11—Parcel APN#3597000006 12—The project site lies within the Urban Conservancy Shoreline Environment Designation (no levee) area and is completely contained within the 100' buffer but landward of the OHWM. The project is also within the FEMA 100 year floodway. The site contains areas sloping between 15% and 40% and underlain by permeable soils and engineered fill. VL Page 2 of 5 08/17/2015 W:\Users\Valerie\SEPA\E15-0007 Staff Report B. ENVIRONMENTAL ELEMENTS: 1. Earth: a—h—Concur with checklist. 2. Air: a-c—Concur with checklist. 3. Water: a(1)—(6)—Concur with checklist. b(1) and (2)—Concur with checklist. c(1)—The project shall meet all King County Surface Water Design Manual drainage requirements. All impacts associated to drainage will be mitigated as part of the construction permit. c(2)— Surface water design and construction shall be per the King County Surface Water Design Manual as adopted by the City of Tukwila. All impacts associated with drainage will be mitigated as part of the construction permit. Best Management Practices must be followed to ensure that no construction debris enters river. All impacts related to construction debris will be mitigated as part of the construction permit. d—Concur with checklist. 4. Plants: a—d—Concur with checklist. 5. Animals: a-d—Concur with checklist. 6. Energy and Natural Resources: a-c—Concur with checklist. 7. Environmental Health: a —Concur with checklist. a(1)-(2)—Concur with checklist. b(1)—Concur with checklist. b(2)-(3)—The project shall be subject to the City's noise ordinance and any construction related noise shall be subject the city's noise ordinance. Compliance with applicable local, state and federal noise regulations will mitigate any potential adverse noise impacts, associated with the project. 8. Land and Shoreline Use: a —The area of the proposed work is undeveloped and adjacent to a parking lot, with a portion of the Green River Trail running through it. VL Page 3 of 5 08/17/2015 W:\Users\Valerie\SEPA\E15-0007 Staff Report b-f—Concur with checklist. g—Concur with checklist. The site is in an un-leveed portion of the river. h— Concur with checklist. The project is also within the FEMA 100 year floodway. The site contains areas sloping between 15% and 40% and underlain by permeable soils and engineered fill. i-1—Concur with checklist. 9. Housing: a-c—Concur with checklist. 10. Aesthetics: a-c—Concur with checklist. 11. Light and Glare: a-d—Concur with checklist. 12. Recreation: a —Concur with checklist. b—The project is within an area where Muckleshoot tribal members exercise their treaty fishing rights. Currently there is no access to the river within the project area. However, the project area is located approximately 150 feet north of an existing trail that is used by tribal member to access the river for fishing. This trail will remain open during construction, parking will be available, and access to the river via the trail will be unimpeded. c—Concur with checklist. 13. Historic and Cultural Preservation: a-b—Concur with checklist. c—Applicant will comply with all local, state, and federal laws in the case that archaeological or paleontological artifacts are encountered. 14. Transportation: a-g—Concur with checklist. 15. Public Services: a-b--Concur with checklist. 16. Utilities: a-b—Concur with checklist. IV. PUBLIC COMMENTS Notice was sent to property owners and tenants within 500' of the site and agencies with jurisdiction. No comments were received from the general public regarding the proposed work. VL Page 4 of 5 08/17/2015 W:\Users\Valerie\SEPA\E15-0007 Staff Report • \ f \ Comments were received from the Muckleshoot Indian Tribe, stating that the project site is an area where Muckleshoot tribal members exercise their treaty fishing rights and that the project must therefore ensure that Tribe members will continue to have access to the Green River during construction. Comments also noted that an increase in fishing in that area is a likely outcome of the project work, as the project may create better river access. The Muckleshoot Tribe also requested to be sent the as -built drawings and any monitoring reports generated by the project for their files. These comments were forwarded to the applicant, who replied by stating that the area of proposed work does not currently provide access to the river, but is located 150' north of the trail that is used by tribal members for fishing. They confirmed that the work will not impede access to this area. VI. CONCLUSION The proposal can be found to not have a probable significant adverse impact on the environment and pursuant to WAC 197-11-340, a Determination of Nonsignificance (DNS) is issued for this project. This DNS is based on impacts identified within the environmental checklist, attachments, and the above "Final Staff Evaluation for Application No. E15-0007", and is supported by plans, policies, and regulations formally adopted by city of Tukwila for the exercise of substantive authority under SEPA to approve, condition, or deny proposed actions. Prepared by: Valerie Lonneman, Assistant Planner Date: August 17, 2015 VL Page 5 of 5 08/17/2015 W:\Users\Valerie\SEPA\E15-0007 Staff Report RECEIVE AUG 07. 2015 -I uKWILA PUBLIC \WORKS City of Tukwila Department of Community Development FILE NUMBER L15-0032 E15-0007 Land Use Routing form for Revisions TO: ❑ Building ❑ Fire Dept. Public Works: (please list the name) ['Police Dept nParks/Rec. Dad, ✓2 N�c �1,�c�•� Project: Green River Bank Erosion Repair Address: 14900 Interurban Ave S. Date transmitted: 8/7/2015 Response requested by: 8/21/15 Planner: Valerie Lonneman Date response received: COMMENTS Responses from architect, civil engineer, and landscape architect included in revision. cov,e_ci,-;, .4:fr--1, s i4, 0,,, 0,0 6 & i s -a o 3 2 — P Z. t G , 2k, s I'l,4 s SOY] F (.5 -boo? — P u 6 Li . U A_C l-4,9s /•( D r►, .rrs - ❑ DRC review requested ❑ Plan submittal requested ❑ Plan approved Plan check date: SA g/ i s Comments prepared by:( City of Tukwila REVISION SUBMITTAL Department of Community Development PLANNING DIVISION 6300 Southcenter Boulevard, Suite #100 Tukwila, Washington 98188 Phone: 206-431-3670 H +' a N • AUG062015 Community peVeiopment Revision submittals must be submitted in person at the Permit Center, ACCOMPANIED BY RESPONSE DOCUMENTS AND THIS COMPLETED FORM. Revisions will not be accepted through the mail, email, fax, etc. TUK M RECE Er, AUG O7.2015 WIL. PUBLIC WORKS Date: 8/6/2015 Permit Number: L15-0032 & E15-0007 Project Name: Green River Bank Erosion Repair Project Address: 14900 Interurban Ave S. Project Contact: Thomas Bannister Contact Phone number: (206) 728-2674 City Planner: Valerie Lonneman PLEASE ATTACH A COPY OF ANY LETTER REQUESTING CORRECTIONS / ADDITIONAL INFORMATION ❑ Response to Preliminary Approval ® Response to letter requesting additional information (Please attach a copy of the letter) ❑ Final Short Plat Submittal Summary of revision/response submittal: The applicant is providing a response memorandum to address comments received from the City of Tukwila in Correction Letter #1. The project design report and SEPA checklist have been revised and resubmitted based on the comments from the City. Received at the City of Tukwila Permit(Center by: entered in TRAKiT on C:\Users\breinke\AppData\Local\Microsoft\Windows\lNetCache\Content.Outlook\81R3103M\L15-0032 Revision Submittal Form.doc Revised: March 2014 City of Tukwila . Jim Haggerton, Mayor Department of Community Development Jack Pace, Director July 14, 2015 GeoEngineers, Inc. Attn: Thomas Banister 600 Stewart Street, Suite 1700 Seattle, WA 98101 tbannister@geoengineers.com Subject: Correction Letter #1 Green River Bank Erosion Repair L15-0032, E15-0007 Dear Mr. Banister: The City is in the process of reviewing your applications for Shoreline Substantial Development and SEPA permits to install a subsurface drainage system and restore an eroded bank on the Green River located at 14900 Interurban Ave. South. Please address the following comments and resubmit relevant documents. Departmental comments are listed below along with reviewer contact information: Public Works —Dave McPherson (206) 431-2448: SEPA — E15-0007 The Environmental Checklist should be revised as follows: B. Environmental Elements 5. Animals c. Yes — This area is part of the Pacific Flyway. A primary corridor for migratory bird species. SHORELINE — L15-0032 Ref. GeoEngineers Report dated June 18, 2015 - Pgl, Site Description - The river is tidally influenced at this point at the uppermost point. Revise the document: Yes — work is at approximately river mile 11.4 and the title influence from recent Green River studies extends as far as river mile 12. USGS considers 200th Street in Kent (river mile 17) to be the spatial extent of the tidal influence. Page 5 of GeoEngineers Report 1st paragraph states "To accommodate this slope angle, the existing asphalt trail at the top of the bank may need to be realigned". Will the trail be replaced and will it have the same alignment? W:\Users\Valerie\SEPA\E15-0007 Green River Bank RepairfCorrection Letter #1 Page 1 of 2 6/24/2015 4 Thomas Banister Green River Bank Erosion Repair L15-0032/E15-0007 Building —Allen Johannessen (206) 433-7163: No comments at this time. Fire —Don Tomaso (206) 971-8723: No comments at this time. Planning —Valerie Lonneman (206) 433-7140: SEPA — E15-0007 • Pg3e — Provide answer • Pg4g — Discuss trail in impermeable section • Pg4h — Provide details of erosion control and contingencies • Pg4c — Salmon are endangered and near the sight SHORELINE — L15-0032 • Pg1, Site Description - The river is tidally influenced at the uppermost point. Revise the document to reflect this. • Pg5 — Please provide details of the proposed Tree Protection if it will vary from the code. • Pg5 — Please provide the approximate square footage of the project (to verify for tree count). • Pg6 — Erosion control details should be provided, both for proposed and contingency. When will you determine if contingency is needed? Do you plan to do turbidity testing? • Pg6 — Please provide a maintenance plan/detail from the building owner. How often? Watering? etc. • Pg6 — Watering is needed for first three years from at least July to October, depending on conditions. How will the site be watered? • Pg7 — Given the small size of the site, is it possible to monitor the whole site in lieu of establishing a transect? Photos will be required. Additional comments: • Please provide more information on how the fabric will affect recruitment? How long does it take to break down? Is mulch to be used? • Please provide diagram of planting extent — how far toward OHW will you plant? Consider using willow stakes at base of slope. Please feel free to contact me with any questions at (206) 433-7140. Sincerely, Valerie Lonneman Assistant Planner Page 2 of 2 RECEIVED GEOENGINEERS.g AUG 07 2015 T K Plaza 600 Building, 600 Stewart Street, Suite 1700, Seattle, Washington 98101, Telet9pga2 WIL RK6206.728.2732 Memorandum www.geoengineers.com To: From: CC: Date: GEI File: Subject: Valerie Lonneman, City of Tukwila Assistant Planner Thomas Bannister and Jon Ambrose, GeoEngineers Kurt Schneider, LD Schneider and Associates July 30, 2015 21493-001-01 Response to Correction Letter #1; L15-0032, E15-0007 AUG 0 6 2015 Community Development The purpose of this memorandum is to provide responses to the City of Tukwila's (City) Correction Letter #1, dated July 14, 2015. The City sent Correction Letter #1 to Thomas Bannister requesting additional information regarding LD Schneider's Green River Bank Erosion Repair project located at 14900 Interurban Avenue in Tukwila, Washington. The City's Correction Letter #1 includes comments from Dave McPherson of the Public Works Department and Valerie Lonneman of the Planning Department. Below are our responses to the City's comments: Public Works - Dave McPherson 1. State Environmental Policy Act (SEPA) (E15-0007) - GeoEngineers revised the SEPA Checklist per Dave McPherson's comments. 2. Shoreline (L15-0032) a. GeoEngineers recognizes that the USGS identifies the Green River at the site as tidally influenced and we have revised the design report accordingly. b. The existing asphalt trail has been damaged from slope failure and is currently closed. No changes to the existing trail are proposed as part of this project. Under an existing easement with LD Schneider, the City agreed to maintain the trail within 40 feet of the Ordinary High Water Mark of the Green River. This easement agreement is attached to the GeoEngineers Design Report. Because the existing trail is located at the top of the bank and at the landward limits allowed by the easement, future trail realignment is not likely. Following bank grading, the trail may be reinstalled in a similar alignment and surfaced with gravel or asphalt. Planning - Valerie Lonneman 1. SEPA (E15-0007) c. The project will require the following materials: i. Approximately 160 cubic yards of native material will be excavated, stockpiled and returned to the riverbank following installation of the proposed drainage system. ii. Approximately 160 cubic yards of clean river bank fill, as specified on Sheet 2 of the revised project designs, will be acquired from a local aggregate source. iii. Approximately 96 cubic yards of topsoil for planting medium, as specified on Sheet 2 of the revised project designs, will be acquired from a local supplier. Memorandum to City of Tukwila July 30, 2015 Page 2 iv. Approximately 3 cubic yards of washed and clean drainrock, as specified on Sheet 2 of the project designs, will be acquired from a local aggregate source. v. Approximately 1 cubic yard of quarry spells as specified on Sheet 2 of the project designs, will be acquired from a local aggregate source. d. The existing asphalt trail has been damaged from slope failure and is currently closed. No changes to the existing trail are proposed as part of this project. Under an existing easement with LD Schneider, the City agreed to maintain the trail within 40 feet of the Ordinary High Water Mark of the Green River. This easement agreement is attached to the GeoEngineers Design Report. Because the existing trail is located at the top of the bank and at the landward limits allowed by the easement, future trail realignment is not likely. Following bank grading, the trail may be reinstalled in a similar alignment and surfaced with gravel or asphalt. e. During construction, the contractor will install necessary erosion controls to prevent sediment from entering the flow of the Green River. The project is located landward of ordinary high water mark (OHWM) and no in -water work is proposed. Construction is scheduled to occur in September 2015 and river flow is expected to be very low with little risk of flow entering the work area. The contractor will deploy necessary erosion and sediment controls in the event of rain during construction. If necessary, the contractor will deploy additional contingency erosion controls, such as straw wattle to comply with state water quality standards. We anticipate that a GeoEngineers Certified Erosion and Sediment Control Lead (CESCL) will provide stormwater management guidance to the contractor during construction. Turbidity in the Green River will be visually monitored during construction. If the project results in a visible plume, the contractor will take immediate corrective action by temporarily stopping earthwork activities and installing additional erosion controls. No turbidity testing is proposed because discharge is not anticipated. Upon the completion of site grading, the contractor will immediately install coir erosion control fabric intended to stabilize the site until vegetation is restored to the bank. f. No endangered plant species are known to occur near the site. Endangered Pacific Salmon occur in the Green River as noted on Page 9 of the SEPA checklist. 2. Shoreline (L15-0032) a. GeoEngineers recognizes that the USGS identifies the Green River at the site as tidally influenced and we have revised our report accordingly. b. The seven mature sycamore trees at the site are extremely valuable to the owner and they will be protected during construction. Because of the lack of available space at the site, it is not possible to protect the mature sycamore per City Code. The contractor will install construction fencing along the landward edge of the work area, waterward of the seven existing sycamore tree following guidance from GeoEngineers. If necessary, the contractor will install 4-foot tall plywood boxes around the trunks of the sycamore trees. During site grading, the contractor will take care when operating equipment in the vicinity of the trees. It is anticipated that the GeoEngineers biologist will be on site observing grading activities in the vicinity of the trees. c. The anticipated area to be revegetated is approximately 4,900 square feet. To restore native riparian vegetation in this area, we recommend the following plant schedule: Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Memorandum to City of Tukwila July 30, 2015 Page 3 Estimated Quantity 12 14 12 12 40 40 40 40 40 d. Common Name Black cottonwood Western red cedar Big leaf maple Pacific dogwood Vine maple Oceanspray Snowberry Western serviceberry Red osier dogwood Scientific Name Populus balsamifera Thuja plicata Acer macrophyllum Corpus nutalli Acer circinatum Holodiscus discolor Symphoricarpos albus Amelanchier alnifolia Corpus sericea Size 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 24—inch in height 24—inch in height 24—inch in height 24—inch in height Spacing 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 5 feet o.c. 5 feet o.c 5 feet o.c 5 feet o.c 5 feet o.c As described above, discharge to the river is not anticipated and turbidity measurement is not proposed. Turbidity will be visually monitored during construction and the contractor will postpone earthwork and take corrective action if a visible sediment plume is observed in the river. e. The owner will maintain the site by removing undesirable vegetation from the site during their routine grounds maintenance regimen. The owner will irrigate newly planted trees/shrubs, on an as -needed basis, from July to October. The owner expects that watering may be required on a weekly basis during the summer. Watering will be completed using a hose or installed irrigation system. f. Monitoring the whole site would require visually estimating the areal cover of the whole site. Estimating areal cover of the entire site may result in some subjectivity whereas, measuring the areal cover along a transect is more objective and repeatable. No revisions to the monitoring methods are proposed unless it is a condition of the City's authorization. Photos will be submitted with annual monitoring reports. GeoEngineers specifies a 100-percent biodegradable coir erosion control blanket. It is our experience that this material does not substantially impact volunteering of plants. The expected functional lifespan of this biodegradable material is less than two years. g. h. Native trees and shrubs will be installed in the disturbed areas of the site as illustrated in Sheet 4 of the revised design plans. Plants may be installed down to the OHWM, depending on the actual area disturbed during construction. Willows are not recommended because of the lack of sufficient hydrology for these species. We have revised our project design report, design plans and SEPA Checklist to reflect the revisions discussed in this memo. Those materials are included in this submittal package. Please contact Thomas Bannister at 206-251-1025 if you need additional information or clarification. Disclaimer. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. SEPA Checklist STATE ENVIRONMENTAL POLICY ACT CHECKLIST Please respond to all questions. Use separate sheets as necessary. Applicant Responses: A. BACKGROUND 1. Name of proposed project, if applicable: Green River Bank Erosion Repair 2. Name of Applicant: LD Schneider and Associates 3. Date checklist prepared: May 18, 2015, Revised July 31, 2015 4. Agency requesting checklist: City of Tukwila 5. Proposed timing or schedule (including phasing, if applicable): Construction is scheduled to begin September 1, 2015 6. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No 7. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Analysis and Design Report by GeoEngineers 8. 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 Agency Comments \\deptstore\City Common \ Teri \KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 1 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 9. List any government approvals or permits that will be needed for your proposal. Shoreline Substantial Development permit from the City of Tukwila. Hydraulic Project Approval (HPA) from the Washington Department of Fish and Wildlife. 10. 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. The project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and topsoil. The subsurface drainage system consists of a perforated 4-inch schedule 40 PVC pipe that will capture subsurface water along the 165-foot length of the bank repair. 11. 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, the tax lot number, and section, township, and range. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located on the bank of the Green River immediately Southeast of the building located at 14900 Interurban Avenue South. 12. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? Yes SEPA Checklist Agency Comments \\dcpt. tore\City Camman\Teri\KJRBY - DECEMBER\SEPA Environmental Review Application-Jam2011.docx Page 2 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments B. ENVIRONMENTAL ELEMENTS I. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous, other: The project is located on the bank of the Green River b. What is the steepest slope on the site (approximate percent slope)? The river bank is naturally at an approximate 25-30 percent slope. However, the escarpment from the recent bank slough is nearly vertical and approximately 9 feet high. . 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. Alluvium consisting of very loose to medium dense silty sand to a depth of approximately 35 feet. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Yes, the bank at this location is subject to drawdown failures. e. Describe the purpose, type, and approximate quantities of any tilling or grading proposed. Indicate source of fill. Approximately 420 yd3 of cut and fill: • Approximately 160 yd3 of native material to remain on site. • Approximately 160 yd3 of imported riverbank fill. • Approximately 96 yd3 of imported topsoil. • Approximately 3 yd3 of 1-inch drain rock. • Approximately 1 yd3 of imported outfall protection. \\deptstore\City Cotnmon\Tcri\K1ROY - DECEMBER\SEPA Environmental Review Application-Jan201 l.docx Page 3 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Yes, erosion could result during clearing of the bank. This erosion will be minimized by installing erosion and sediment controls during construction. The site will be permanently stabilized using a robust revegetation plan. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? No new impervious surface is proposed. The trail damaged from slope failure and is closed. Owner may propose trail improvements as part of a future submittal. City agreed to maintain the trail within 40 feet of the OHWM of the Green River. Because the existing trail is located at the top of the bank and at the landward limits allowed by the easement, future trail realignment is not likely. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Temp erosion/sediment controls will be installed prior to site work. Primary water quality protection will be a silt fence installed on the downslope construction limits, near OHWM. Contingency protections include add'l silt fence, silt curtains & straw wattles. Stormwater discharge from the site to be visually monitored. Stormwater discharge is not anticipated during construction because of the typically hot/dry conditions during the expected construction period in Sept. 2015. No work/equipment will occur waterward of OHWM. 2. Air a. What types of emissions to the air would result from the proposal (for example, dust, automobile odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Minor emissions will result from the use of construction equipment and trucking of materials. b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. No. SEPA Checklist Agency Comments \\deptstore\City Common \ Teri \KIRBY - DECEMBER\SEPA Environmental Review Application-Jan20l 1.docx Page 4 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: c. Proposed measures to reduce or control emissions or other impacts to air, if any: None, 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. The Green River is located immediately waterward of the site. The Green River is a Shoreline of the State (Type S). 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. The project will be located wholly within 200 feet of the Ordinary High Water Mark (OHWM) of the Green River. 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. No work will occur waterward of the OHWM. SEPA Checklist Agency Comments \\dept,tore\City Common\TcriUURI3Y - DECEMBER\SEPA Environmental Review Application•lan2011.docx Page 5 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 4. Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities, if known. No. 5. Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. Yes. 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. b. Ground: 1. Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. No. SEPA Checklist Agency Comments \WeptatnrelCity Common \Teri\K1RBY - DECEMBER\SEPA Environmental Review Application-lan2OI t ,docx Page 6 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 2. Describe waste materials that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc). Describe the general size of the system, the number of such systems, the ntunber of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve: None. 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? Will this water flow into other waters? If so, describe. The project consists of installing a subsurface gravity drainage system to transport water away from the riverbank. The drainage system consists of PVC pipe that will capture subsurface water along the 165-foot length of the bank repair. This groundwater will flow to outfalls located at OHWM of the Green River. We anticipate that this flow will be less than 1 gallon per minute under normal conditions. 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: Surface water runoff from the site is not anticipated. Outfall protection will be installed to minimize the potential fro erosion of the bank. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DCCLsMBWR\SBPA Environmental Review Application-Jan2O1 l.docx Page 7 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 4. Plants a. Check or circle types of vegetation found on the site: ✓ Deciduous tree: alder, maple, aspen, other — Evergreen tree: fir, cedar, pine, other ✓ Shrubs Grass Pasture Crop or grain Wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other Water plants: water lily, eelgrass, milfoil, other Other types of vegetation b. What kind and amount of vegetation will be removed or altered? Vegetation that will be removed consists of noxious and invasive Himalayan blackberry and English ivy. c. List threatened or endangered species known to be on or near the site. None. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: Noxious and invasive species will be removed from the project area and the bank will be restored with native trees and shrubs. Agency Comments 1ldepttorre\City Conlon\Teri\KERE3Y - DE CFMI3FR\SFPA Environmental Review Application-Jan20I i_dncx Page 8 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 5. Animals a. Circle any birds or animals which have been observed on or near the site or are known to be on or near the site: Birds: eawD heron, 4n, on bird other: Mammals: Deer, bear, elk, beaver, Wier: Fish: Bass, almo ou herring, shellfish, other: Other: b. List any threatened or endangered species known to be on or near the site. The Green River is habitat for endangered Pacific salmon including Chinook salmon, steelhead trout and bull trout. c. Is the site part of a. migration route? if so, explain. Yes. The green River is a primary migration route for anadromous salmonids. This area is part of the Pacific Flyway, a primary corridor for migratory bird species. d. Proposed measures to preserve or enhance wildlife, if any: The project propsed to substantially enhance riparian habitat by removing invasive plants and installing native trees and shrubs. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. None. \\deptstore\City Common1Teri\KIRBY - DECEMBER\S) PA Environmental Review Applieetion-Ju 01 l.docx Page 9 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 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: None. 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 environmental health hazards, if any: None. SEPA Checklist Agency Comments 1\depistore\City ConfmonVrcri\K.IRI3Y - DECEMI3ER\SEPA Environmental Review Application-]an2011.doex Page 10 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments b, Noise 1. What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? The project will not be affected by existing sources of noise. 2. What types and levels of noise would be created by or associated with the project on a short-term or long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. The project will result in short term elevated levels of noise from construction equipment. However, baseline noise levels are high due to traffic on Interurban Avenue South and an existing capital improvement project adjacent to the site. 3. Proposed measures to reduce or control noise impacts, if any: None. S. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site is currently used as light commercial office space with associated parking areas. b. Has the site been used for agriculture? If so, describe. Yes, Aerial imagery from King County indicates that the site was farmed in the 1930's. 1\deptstora\City Common\TeriUURBY - DECEMBER\SEPA Environmental Review Application-Jan301 l.docx Page 1 1 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: G. Describe any structures on the site. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. d. Will any structures be demolished? If so, what? No. e. What is the current zoning classification of the site? Regional Commercial Mixed -Use (RCM). f. What is the current comprehensive plan designation of the site? Regional Commercial Mixed -Use (RCM). g. If applicable, what is the current shoreline master program designation of the site? Urban Conservancy. SEPA Checklist Agency Comments 11deptstnre\City Cammon\Teri\KIRBY - DECEMBER\SEI'A Environmental Review Appliontion-Jan2011.docx Page 12 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: li, Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. Yes. The site is wholly within the 100-foot wide river buffer. 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: N/A. 1, Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: N/A. SEPA Checklist Agency Comments lldeptxmrc\City Common \Teri KlRBY • DECEAMBER\SEPA Environmental Review Application-inn201 I.docx Page 13 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 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 eliminated? 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? The prosposed trees may obscure the the existingviews of the river. SEPA Checklist Agency Comments \\deptslore\City Common\Teri\KIRBY - D1:CEMtiER\SliPA Environmental Revinv Application-Jan2011.docx Page 14 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: c. Proposed measures to reduce or control aesthetic impacts, if any: The proposed planting plan has been developed to maintain existing view corridors to the extent practical. 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? N/A. 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: N/A. SEPA Checklist Agency Comments \\depI tore\City Common\Teri\KIRRY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 15 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 12. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? The owner maintains an existing asphalt pedestrian trial located at the top of the riverbank.. A primitive trail is located approximately 200 feet south of the site which is used by anglers to access the river. 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: None. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, National, State, or Local preservation registers known to be on or next to the site? If so, generally describe. None known. 1ldtptstoralCity Common\Tcri\KIRBY - DECEMBERISEPA Environmental Review Application-Jan201 I.docx Page 16 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None known. c. Proposed measures to reduce or control impacts, if any: N/A l4, `transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. The site is accessed from Interurban Avenue South via the existing parking area on the south side of the property. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Bus routes are located on Interurban Avenue South. Bus stops are located approximately 500 feet north and south of the site. c. How many parking spaces would the completed project have? How many would the project eliminate? The project proposes no parking and no parking will be eliminated. SEPA Checklist Agency Comments \\deptstore\City Commun\Teri\KIRBY - DECEMBER\SEPA Environntentul Review Application-lan20114ocx Page 17 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 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. No. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. No project will not generate vehicle trips. g. Proposed measures to reduce or control transportation impacts. if any: N/A. 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. SEPA Checklist Agency Comments \\deptstore City Cummon\Teri\KIRBY - DECEMHI R\SEPA Environmental Review Appiication•Jan2011.docx Page 18 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: b. Proposed measures to reduce or control direct impacts on public services, if any. N/A. 16. Utilities a. Circle utilities currently available at the site: r eCtrici '� •� iiiiii'1( ,1railf Yar+ii•7+ system other: septic 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. No utilities are proposed for the project. SEPA Checklist Agency Comments Adeptstorc\City Common\Tcr11K1RBY - DECEMBER\SEPA Environmental Review Application-7un2011.docx Page 19 SEP4 Checklist (NON -PROJECT PROPOSALS (E.G., SUBURBAN PLANS AND ZONING CODE TEXT CHANCES) MUST COMPLETE THE FOLLOWING PAGES). C. SUPPLEMENTAL SHEET FOR NON -PROJECT PROPOSALS (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 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 implemented. Respond briefly and in general terms. Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 1. How would the proposals be likely to increase discharge to water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? Proposed measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants, animals, fish, or marine life? Proposed measures to protect or conserve plants, animals, fish, or marine life are: \\Jeptstore\City Comtnon\Tcri\K1RBY - DECEMI3ER\SEPA Environmental Review Application-Jan2011.docx Page 20 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 3. How would the proposal be likely to deplete energy or natural resources? Proposed measures to protect or conserve energy and natural resources are: 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 habitats, historic or cultural sites, wetlands, floodplains, or prime farmlands? 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, including whether it would allow or encourage land or shoreline uses incompatible with existing plans? Agency Comments \\deptetore\City Common\Teri1KIR$Y - DECEMIER\SEMA Environmental Review Apptication.Jun2011.ducx Page 2 I S.EPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Proposed.measures to avoid or reduce shoreline and land use impacts are: 6. Row would the proposal be likely to increase demands on transportation or public service and utilities? 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. D. SIGNATURE Agency Comments Under the penalty of perjury the above answers under ESA Screening Checklist and State Environmental Policy Act Checklist are true ancomplete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision Signature: Date Submitted: 1\deptstore\City Common \Teri\KIR13Y - DECEMBERISEPA Environmental Review Applicntion•den2011.docx Page 22 ♦J GEOENGINEERS117 Plaza 600 Building 600 Stewart Street, Suite 1700 Seattle, Washington 98101 206.728.2674 July 30, 2015 fnt LD Schneider and Associates Oe o� elf 3200 North Central Avenue, Suite 1470 � Phoenix, Arizona 85012 Attention: Kurt Schneider 4-1 INTRODUCTION Subject: Revised Analysis and Design Report Green River Bank Repair 14900 Interurban Avenue South Tukwila, Washington GeoEngineers File No. 21493-001-01 F ECEUVF AU6 07 2015 TUKvviLA PUBLIC WORKS iJ GeoEngineers, Inc. (GeoEngineers) is pleased to present an analysis of site conditions and a design to repair an eroding bank along the Green River adjacent to the property at 14900 Interurban Avenue South r-1 Permit and to the Washington State Department of Fish and Wildlife (WDFW) for a Hydraulic Project Approval (HPA). We prepared this report to comply with the submittal requirements of Tukwila Municipal Code (TMC) 18.44. in Tukwila, Washington. The location of the site is mapped on Sheet C-1 in Appendix A. The purpose of this report is to support an application to the City of Tukwila (City) for a Shoreline Substantial Development `J GeoEngineers submitted the original version of this report to the City on June 24, 2015. Following receipt of comment from the City, detailed in Correction Letter #1, we revised this report to address the City's comments and to provide further clarification regarding the proposed project. 0-1 GeoEngineers assessed the causes of bank failure and developed multiple design alternatives for consideration by the owner. We also evaluated the permitting considerations of each option. As part of our preliminary work, we completed a site assessment and developed a design to address the mechanisms of bank failure. This report details our methods and findings regarding site conditions, mechanism of failure and presents permit level design drawings to mitigate for bank failure and restore the bank to a functional condition. 7� v l'%uni pm� •, lJ LD Schneider and Associates July 30, 2015 Page 2 SITE DESCRIPTION AND CONDITIONS The 3.6-acre property (Parcel #3597000006) is located on the left (west) bank of the Green River. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. The parcel is generally flat and the river is not leveed. According to the US Geologic Survey (USGS), the Green River is tidally influenced at this location. Overbank bank flooding is extremely rare, particularly on the left bank of the river. The area of the parcel that is within 200 linear feet of the Ordinary High Water Mark (OHWM) of the Green River is regulated under the City of Tukwila's Shoreline Master Program. The Shoreline designation for the site is Urban Conservancy and the River has a buffer of 100 feet measured from OHWM. The site is also designated as a Fish and Wildlife Habitat Conservation Area per TMC 18.44.090 H. A GeoEngineers biologist made a preliminary site visit on May 13, 2014. In general, the riverbank on the property is vegetated with noxious and invasive Himalayan blackberry. Because of the infestation of Himalayan blackberry and lack of trees, habitat conditions along the riverbank are degraded. GeoEngineers observed evidence of a recent slough of the bank located approximately 100 feet southeast of the commercial building on the property. The recent sloughing resulted in an approximately 10-foot high near vertical escarpment that damaged an existing asphalt trail at the top of the bank. The trail is separated from the parking lot by a landscaping island consisting of grass and a row of seven mature sycamore trees. The biologist also observed water weeping from the bank at the toe of the escarpment. The biologist did not observe environmentally sensitive areas, such as wetlands, during the site reconnaissance. On August 12, 2014, a GeoEngineers geotechnical engineer, river hydrologist, and biologist evaluated slope stability, habitat, and flow conditions at the site. During this site visit, the geotechnical engineer noted that the soil exposed in the riverbank consisted of fine to medium silty sand and silt. This material is typical of alluvium in the Green River valley. Bedrock was observed in the riverbanks upstream (south) of the property. Bedrock is also known to be present (State of Washington Department of Natural Resources [DNR] Geology Maps) on the hillside to the west of the site. DNR maps the local geologic unit as the Puget Group (Tp). The Puget Group consists of sandstone, siltstone, claystone, and coal which is white and very fine grained to gritty. The Tiger Mountain Formation, which consists of light-colored, medium -grained sandstone with siltstone, minor pebble conglomerate, and coal beds, is mapped in isolated outcrops in the river valley. The Renton Formation (Tpr), which is a fine- to coarse -grained sandstone with interbedded siltstone, claystone, and coal, is mapped on the hillside to the west of the site. Alluvial deposits (Qal) are mapped immediately adjacent to the site as comprising the river bed and riverbanks. Alluvium is described as a mix of moderately to poorly sorted granular soils deposited by the river. We completed two subsurface geologic explorations at the top of the recently sloughed area where the trail has become undermined and approximately halfway between this point and the corner of the building. These explorations were performed with a track -mounted drill rig and advanced to a depth of 36.5 feet (at the top of the slough) and 51.5 feet (nearer to the building). Summary logs of our explorations are included as Appendix A. The subsurface conditions at the site is consistent with a glacial channel that was carved into siltstone and sandstone and then partially filled with more recent alluvium from the Green River. We observed the alluvium to consist of very loose to medium dense silty sand to a depth of approximately 35 feet. We GEOENGINEERS� File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 3 lJ observed the silty sand material to overlie a white to light gray sandstone with fine inclusions of coal layers. We interpret this sandstone to be a part of the Tiger Mountain Formation of the Puget Group. The two borings were terminated within the sandstone. We observed groundwater in the borings at a depth of approximately 12-14 feet below ground surface, which is consistent with earlier observations of groundwater seeping out from the toe of the sloughed surface. MECHANISM OF BANK SLOUGHING Based on our observations at the site and experience in the Green River valley, it is our opinion that the bank sloughing is most likely due to a drawdown failure. This type of failure occurs when high groundwater levels and high river levels saturate the riverbank soil and then the river levels drops or "draws down" faster than the water can drain from the riverbank soil. This creates an imbalance of water pressure. The water pressure pushing the bank from within the soil is no longer balanced by the water pressure from the river and the riverbank is pushed into the river. In our experience, this is the most common riverbank failure mechanism on the lower Green River. Toe erosion is also a failure mechanism that is common on the Green River and often found in conjunction with drawdown failures. Toe erosion will weaken a riverbank but the ultimate failure is triggered by drawdown. At this site, the presence of shallow bedrock makes toe erosion less likely to be a significant contribution to the failure of the riverbank. In addition to site observations, bathymetric data of the channel bottom was obtained from King County. Cross sections of the channel bottom in the vicinity of the site do not show the large scour holes typically evident in areas where toe erosion is a major contributor to slope instabilities. We do not believe toe erosion to be a contributing factor in the of bank sloughing at the site. PROJECT DESIGN We developed a permit -level design to mitigate for the bank sloughing and also to address potential future drawdown failures. Permit level design drawings are included as Appendix B. The design objective was to develop a plan appropriate for the site geology and geometry using techniques and materials most likely to r� be approved by regulatory agencies and offer long term protection. During preliminary design, we considered bio-engineered and hard engineering approaches. The identified design options are located landward of the OHWM for permitting efficiency. Additionally, we believe work waterward of OHWM is unnecessary because the mechanism of failure is not a result of toe erosion. As such, the project will avoid LJ impacts to aquatic habitat at the site. Riverbank Drainage The project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and native soil. The subsurface drainage system consists of a perforated 4-inch schedule 40 polyvinyl chloride (PVC) pipe that will capture subsurface water along the 165-foot length of the bank repair. Solid 4-inch PVC finger drains set at approximately 20-foot intervals will convey the water from the perforated pipe to outfalls located GEOENGINEERS File No. 21493-001-01 LJ LD Schneider and Associates July 30, 2015 Page 4 landward of OHWM. Small rock will be installed at the outfalls to protect against erosion. This rock is designed to withstand flows from the pipe and sheer stress of river flows under anticipated conditions. This design will reduce the water pressure upgradient of the riverbank and thereby reduce the potential for future drawdown failures. The project is designed to address the primary cause of bank failure (drawdown) and does not include design elements to protect against toe erosion or scour. We anticipate that a qualified contractor will install the drainage system and restore the bank using a medium-sized track mounted excavator and other support equipment. The project will be completed during WDFW's allowable in water work window, or approximately August 1- August 31. Construction is estimated to take approximately 2 weeks. Because the project is located in the 100-foot buffer of the Green River, TMC 18.44.090 E(4) requires the owner, the specialist of record (GeoEngineers), the contractor and representatives from the City of Tukwila to attend a preconstruction meeting at the site. Per TMC 18.44.090 E(5), GeoEngineers will be retained to monitor construction. We estimate that approximately 420 cubic yards (yd3) of material will be cut and filled to complete the project. Of this 420 cubic yards of material, approximately 160 cubic yards will be native material that will remain on site and will be incorporated back into the riverbank. It will be necessary to import additional material to achieve the design elevations and grades. This material and the estimated quantities are listed below. Anticipated Material Schedule Approximately 420 yd3 of cut and fill: • Approximately 160 yd3 of native material to remain on site. • Approximately 160 yd3 of imported riverbank fill. • Approximately 96 yd3 of imported topsoil. • Approximately 3 yd3 of 1-inch drain rock. • Approximately 1 yd3 of imported outfall protection. Stability Analysis of Design We analyzed the proposed slope repair using the computer program SLOPE/W (GEO-SLOPE International, Ltd., 2012). The SLOPE/W program evaluates the stability of numerous trial shear surfaces using a vertical slice limit -equilibrium method (Morgenstern -Price). This method compares the ratio of forces driving slope movement to the forces resisting slope movement for each trail shear surface, and presents the ratio as the factor of safety. The program then sorts the trail shear surfaces and identifies the surface with the lowest factor of safety, or the "critical" shear surface. We first analyzed the slope in what was likely its configuration just prior to the slough occurring. Our analysis was based on the subsurface data collected in our explorations and on groundwater conditions consistent with a drawdown condition. For this condition we calculate that the factor of safety is less than 1.0. This indicates that the forces driving slope movement exceed the forces resisting slope movement and that the slope would fail. Additionally, the calculated critical shear surface is similar to the observed shear surface of the slough. This result further corroborates our opinion that the bank slough was triggered by drawdown. GEOENGINEERS,..0 File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 5 We then analyzed the slope with the proposed repair in place. In this case we calculate that the factor of safety against a drawdown type failure is 1.3, indicating that the forces available for resisting slope movement exceed the forces driving slope movement by about 30 percent. As a point of reference, the United States Army Corps of Engineers (USACE) recommends a calculated factor of safety greater than about 1.0 or 1.1 against drawdown failures. Site Restoration Following installation of the riverbank drainage, the disturbed areas will be restored and enhanced. The design goal for the project is to reconstruct the bank at an approximate pre -slough slope angle, or 2.5:1 slope. However, the slope angle of the bank reconstruction will be established to fit within the site constraints, including avoiding damage to the large sycamore trees atop the bank, limiting disturbance to the root zone and transitioning into the native banks adjacent to the repair. To accommodate this slope angle, the existing asphalt trail at the top of the bank may need to be realigned. The alignment of the trail will be established following restoration of the bank. However, under an existing easement with the property owner, the City will maintain the trail within 40 feet of OHWM. The easement agreement is included as Appendix D. Due to the anticipated sheer force during high flow events in the river, we anticipate that the reconstructed bank will require additional erosion protection. 0ur design includes a biodegradable erosion control fabric designed to withstand sheer stresses under normal flow conditions. The erosion control fabric will also stabilize the bank slope from raveling during heavy rain events. Because the project will be completed landward of OHWM, we do not anticipate temporary or permanent impacts to the aquatic habitat of the Green River. Temporary impacts will be limited to the blackberry and English ivy infested bank above OHWM. No trees will be removed as part of the project. The seven mature sycamores along the top of bank will be protected during construction per the requirements of the Shoreline Substantial Development permit. Because of the proximity of these mature trees to the work area it is not practical to protect the trees in the manner required by TMC 18.44.080 B (10). GeoEngineers recommends that the contractor establish tree protections at the maximum practical distance from the trunks of the sycamore trees to complete the project. We recommend that the contractor install high visibility construction fencing between the work area on the bank and the sycamore trees that are located approximately 15 to 20 feet landward from the top of the riverbank. If necessary that contractor will install 4-foot high plywood boxes around the trunks to further protect the trees. During site grading, the contractor will take care when operating equipment in the vicinity of the trees. It is anticipated that the GeoEngineers biologist will be on site observing grading activities in the vicinity of the trees. The work area is currently infested with Himalayan blackberry which will be removed during construction. The project design includes aggressive revegetation to reestablish root strength and help stabilize the bank. Native plant species will be densely installed in the areas disturbed by the project. Below is a list of recommended plants to be installed at the site to reestablish root structure and appropriate riparian habitat. The estimated plant quantities are based on a 4,900 square foot disturbance area. Installed plant quantities may vary based on the actual disturbance area. GEOENGINEERS File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 6 Estimated Quantity 12 14 12 12 40 40 40 40 40 Common Name Black cottonwood Western red cedar Big leaf maple Pacific dogwood Vine maple 0ceanspray Snowberry Western serviceberry Red osier dogwood Scientific Name Populus balsamifera Thuja plicata Acer macrophyllum Corpus nutalli Acer circinatum Holodiscus discolor Symphoricarpos albus Amelanchier alnifolia Corpus sericea Size 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 24—inch in height 24—inch in height 24—inch in height 24—inch in height Spacing 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 5 feet o.c. 5 feet o.c 5 feet o.c 5 feet o.c 5 feet o.c We developed this native plant palette based on our experience with riparian restoration and with guidance from WDFW (Cramer, 2012). We increase the density of the installed trees to 10 feet on -center at the request of WDFW (2015). Installed deciduous trees will be 2-inch caliper, conifer will be 6-8 foot height and shrubs will be 24-inch height in compliance with TMC 18.44.080 C(1)(j). Trees will be planted on 10-foot spacing per WDFW's request and shrubs will be planted on 5-foot spacing per TMC 18.,44.080 C(2)(d). To enhance aquatic habitat, the GeoEngineers biologist will provide guidance to the contractor in installing the plants in locations that promote shade and overhanging vegetation near OHWM while maintaining the view corridors of the existing riverfront trail. Large trees will be installed outside the drip line of the existing sycamore trees. The planting plan also accounts for the seasonally fluctuating river levels and variable hydrology up the slope of the riverbank. Because of the typical hot and dry conditions during WDFW's allowable work window, we recommend that the revegetation of the riverbank be delayed until late fall. Planting in late summer will likely result in plant failure and poor revegetation. The erosion control fabric installed on the riverbank will stabilize the bank in the interim between repair of the bank and site revegetation. To avoid and minimize water quality impacts during construction, temporary erosion and sediment controls will be installed prior to site work. A silt fence will be installed on the downslope construction limits, near OHWM, as the primary water quality protection. Contingency water quality protections include additional silt fence, silt curtains and straw wattles. Stormwater discharge from the site will be visually monitored. It is not anticipated that there will be a stormwater discharge during construction because of the typically hot and dry conditions during the expected construction period in September 2015. No work will occur waterward of OHWM and construction equipment will not work in the water. Should a problem arise the contractor will postpone earthwork and take corrective action to comply with state water quality standards. We estimate the cost to construct the bank repair to be approximately $65,000. 0ur Project Value documentation is included as Appendix C. GEOENGINEERS� File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 7 Maintenance and Monitoring We anticipate that the riverbank drainage system will require minimal maintenance. Maintenance will include occasional flushing of the system via backwashing from the outfalls. The frequency of this maintenance will be determined on an as needed basis. The restored vegetation on the bank will be managed by the on -site property management staff. We anticipate that the riverbank will be maintained as a part of their routine maintenance regimen. Maintenance will include physical removal of noxious and invasive species that may be detrimental to the restored riparian habitat along the riverbank. These noxious and invasive species include but are not limited to: • Knotweeds (Polygonum spp.) • Butterfly bush (Buddleja spp.) • Himalayan blackberry (Rubus armeniacus) • English ivy (Hedera helix) • Scotch broom (Cytisus scoparius) Use of chemical herbicides to control these species is considered unnecessary and is not recommended. We recommend that the installed plants be watered during the dry season for a minimum of three years following plant installation. This watering should occur during the late summer (July to October) and the frequency shall be determined based on weather conditions and plant performance. We anticipate that the site will be watered using a hose or a temporary irrigation system. Beneficial volunteer plants, such as other native species, will be encouraged at the site. Installed plants that do not survive will be replaced as required by the authorizations from the City of Tukwila and WDFW. We anticipate that a provision of the permit issued by WDFW will require 80 percent survival of installed plants for three years following construction of the project. The City of Tukwila will likely require monitoring of the site for a period of five years following plant installation. To monitor performance of the restored vegetation and to comply with project permits, a qualified biologist will annually monitor the site for a period of five years following construction of the project. To track vegetation performance at the site through the monitoring period, we recommend that the monitoring biologist establish a transect along the bank. Using the line intercept method, the biologist will inventory the number and species of native plants observed within 1 foot of either side of the transect shortly following installation of the plants. The location, orientation and length of this transect will be determined in the field by the biologist. The endpoints of the transect will be marked in the field. The biologist will return to the site on an annual basis to complete the survival inventory at the location of the transect. The biologist will determine annual survival rates which will be used to gauge compliance with WDFW's permit. Our experience has shown that calculating survival rates is problematic because of the inherent difficulty of identifying individual plants as the site matures. We recommend that the biologist also measure the areal cover of beneficial vegetation along the length of the transect. It is our opinion that measuring the areal cover of native plants is a better indicator of site performance, is more repeatable and results in less variability amongst site investigators during the monitoring period. Native volunteer plants will be included in the plant inventory and areal cover measurements for the remainder of the monitoring period. Monitoring will include photo documentation of the site. GEOENGINEERS File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 8 The biologist will complete monitoring events on an annual basis for five years following plant installation. The findings of each monitoring event will be documented and the owner will submit annual reports to the City of Tukwila and WDFW. NO NET LOSS ANALYSIS AND MITIGATION SEQUENCING Consistent with the City of Tukwila's Shoreline Master Program (SMP), this project will result in no net loss of shoreline ecological function. The project will result in approximately 5,000 square feet of temporary impacts to the shoreline. These impacts are necessary to eliminate the inherent public safety issue posed by the slope failure and to maintain safe, public access to the shoreline on the property. To rectify these unavoidable impacts, the project follows the mitigation sequencing steps identified in TMC 18.44.070 H(3). Because the project is located landward of OHWM, it avoid impacts to the aquatic environment of the Green River. The riparian habitat that will be impacted by the project is heavily degraded and infested with noxious and invasive plants species. The project proposes to restore and enhance the riparian habitat by removing invasive species and installing native trees and shrubs. The owner is committed to maintaining and monitoring the impacted area to ensure the success of the restoration. As a result of these mitigation steps, the project results in no net loss of shoreline ecological function. We estimate that approximately 200 cubic yards of bank material sloughed into the river during a recent drawdown failure. Much of this material has subsequently been eroded and carried downstream by the river. The drawdown failure resulted a 9-foot high vertical escarpment that damaged the existing public access trail. The escarpment poses a safety risk which has resulted in the closure of the trail. To eliminate this safety hazard, the project will add approximately 160 cubic yards of fill material. This fill material is intended to replace a portion of the bank lost as a result of drawdown failure. We consider this amount of fill to be minor and will have no measureable impact to the hydrology, habitat or other shoreline function. REFERENCES Cramer, Michelle L. (managing editor). 2012. Stream Habitat Restoration Guidelines. Co -published by the Washington Departments of Fish and Wildlife, Natural Resources, Transportation and Ecology, Washington State Recreation and Conservation Office, Puget Sound Partnership, and the U.S. Fish and Wildlife Service. Olympia, Washington. • WDFW. 2015. Personal Communication between Larry Fisher (WDFW) and Thomas Bannister r (GeoEngineers) on June 9, 2015. LIMITATIONS We have prepared this revised report for LD Schneider and Associates for failing bank along the Green River adjacent to the property at 14900 Interurban Avenue South in Tukwila, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the fields of geotechnical engineering, hydrology, and restoration design engineering in this area at the time this report was prepared. The conclusions, recommendations and EO NGINEERS File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 9 opinions presented in this report are based on our professional knowledge, judgment and experience. No warranty, express or implied, applies to our services and this report. Any electronic form, facsimile or hard copy of the original document (email, text, table and/or figure), if provided, and any attachments should be considered a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Sincerely, L.1..1.151.J 1. HSSocldie rlyuruiogisl TAB:LIS:JMA:Ieh Attachments: Appendix A. Geologic Boring Logs Appendix B. Permit Level Design Drawings Appendix C. Project Value Documentation Appendix D. Trail Easement Agreement One copy submitted electronically Senior Geotechnical Engineer Disclaimer. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. GEOENGINEERS File No. 21493-001-01 APPENDIX A Geologic Boring Logs LJ SOIL CLASSIFICATION CHART ADDITIONAL MATERIAL SYMBOLS L J ..J LJ r-1 J LJ LJ r7 LJ n J n n L_J n tJ LJ LJ n LJ u n LJ MAJOR DMSIONS SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER COARSE GRAINED SOILS MORE THAN 50% RETAINED ON NO. zoo SIEVE GRAVEL AND GRAVELLY SOILS MORE THAN 50%OF COARSE FRACTIONIP RETAINED ON NO.4 SIEVE CLEAN GRAVELS (UTILE OR NO FINES) OUV C o ° o ) N� Gw WELL -GRADED GRAVELS, GRAVEL -SAND MIXTURES D 0 0 o o c D O O o C GP POORLY -GRADED GRAVELS, GRAVEL - SAND MIXTURES GRAVELS WITH FINES (APPRECIABLE NES))Max+T ° GM SILTY GRAVELS, GRAVEL - SAND -SILT MIXTURES Ap G`. CLAYEY GARAVELS, GRAVEL - Y MIXTURES SAND AND SANDY SOILS MORE THAN 50% OF COARSE FRACTION PASSING NO. 4 SIEVE CLEAN SANDS (LITRE OR NO FINES) ° ^ elm WELL -GRADED GRAVELLY SANDS DS, SP POORLY -GRADED SANDS, GRAVELLY SAND SANDS WITH FINES (APPRECIABLE AMOUNT OF FINES) SM SILTY SANDS, SAND - SILT MIXTURES /•/ SC CLAYEY SANDS, SAND - CLAY MIXTURES FINE GRAINED SOILS MORE THAN 50% PASSING NO.200 SIEVE SILTS AND CLAYS LESSU%50 ML INORGANIC SILTS, ROCK FLOUR, CLAYEY SILTS WITH SLIGHT PLASTICITY CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDYEANCLAYSS, SILTY OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY SILTS CLAYS LIQUID LIMIT GREATER THAN 50 J MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS SILTY SOILS / Cl..l GnACNITMCLAYS OF HIGH P OH ORGANIC CLAYS AND SILTS OF MEDIUM TO HIGH PLASTICITY HIGHLY ORGANIC SOILS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS = — — - - - PT NOTE: Multiple symbols are used to indicate borderline or dual soil classifications LI • W Sampler Symbol Descriptions 2.4-inch I.D. split barrel Standard Penetration Test (SPT) Shelby tube Piston Direct -Push Bulk or grab Continuous Coring Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (or distance noted). See exploration log for hammer weight and drop. A "P" indicates sampler pushed using the weight of the drill rig. SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER AC Asphalt Concrete CC Cement Concrete CR Crushed Rock/ Quarry Spalls TS Topsoil/ Forest Duff/Sod o/oF AL CA CP CS DS HA MC MD OC PM P1 PP PPM SA TX UC VS NS SS MS HS NT Groundwater Contact Measured groundwater level in exploration, well, or piezometer Measured free product in well or piezometer Graphic Loa Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Material Description Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Laboratory / Field Tests Percent fines Atterberg limits Chemical analysis Laboratory compaction test Consolidation test Direct shear Hydrometer analysis Moisture content Moisture content and dry density Organic content Permeability or hydraulic conductivity Plasticity index Pocket penetrometer Parts per million Sieve analysis Triaxial compression Unconfined compression Vane shear Sheen Classification No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen Not Tested NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to be representative of subsurface conditions at other locations or times. KEY TO EXPLORATION LOGS J GEOENGINEERS FIGURE A-1 Start End Total 51 5 Depth (ft) Logged BfAW/SST Checked By LJS Driller Holocene Drilling Inc. Drilling Hollow Stem Auger Method Drilled 4/23/2015 4/23/2015 Surface Elevation (ft) 28 Vertical Datum NAVD88 Hammer Auto Hammer Data 140 (Ibs) / 30 (in) Drop Drilling Diedrich D50 Truck Rig Equipment Easting (X) Northing (Y) System Datum Groundwater Depth to Date Measured Water (ft) Elevation (ft) Notes: See Remarks 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I I I ♦ 'o 's 20 `'s Elevation (feet) 'o o Depth (feet) i i 1 1 i i 1 i 1 i i i i I i i i i I FIELD DATA Graphic Log I Group Classification Moisture Content (%) Fines Content (%) Interval Recovered (in) Blows/foot Collected Sample Sample Name Testing Water Level MATERIAL DESCRIPTION REMARKS J 2 12 3 4 2A ML Brown silt with sand, occasional organic matter (twigs, duff) (soft, moist) 1 1 18 4F 26 ML _ Brown silt with sand (medium stiff, moist) _ (alluvium) 21 56 8 1 3 aA MC / ML Brown silt, trace sand (soft, moist) (alluvium) 48 18 1 18 1 14 118 5 9 10 7 4B S 6 7 8A SM Gray silty sand (very loose, moist) (alluvium) Grades to loose, wet 33 36 Groundwater observed at 14 feet at time of drilling - 20--] ) — 14 3 ae 9 %F ML _ Gray silt, trace sand (medium stiff, moist) (alluvium) 57 98 - 25 --]SP-SM - 30--I _$n — = 351 Note: See 16 12 18 Figure 22 21 25 A-1 for t0 11 12 explanation of symbols. _ Gray fine to coarse sand with silt (medium dense, — wet) (alluvium) Log of Boring B-1 GEOENGINEERS.g Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-2 Sheet 1 of 2 6• 7 u cJ -1 ♦J n U n LJ n lJ U n n r1 4930011GINT12149300101.GPJ DBTemplate/LlbTemplate.GEOENGINEERS8.GDT/GEI8_GEOTECH STANDARD Elevation (feet) - 40� 12 22 Recovered (in) FIELD DATA a E o d 3 0 2 U m U E Z F Water Level MATERIAL DESCRIPTION e � c y C iU REMARKS - as� 18 so 50-1 18 73 13A 13B 14 15 SAND Sandstone: white; visually fresh; fine grained STONE - (Puget Group Tiger Mountain formation) Note: See Figure A-1 for explanation of symbols. Log of Boring B-1 (continued) G EO N G I N E S RS E ri, Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-2 Sheet 2 of 2 Start End Drilled 4/23/2015 4/23/2015 Total 36.5 Depth (ft) Logged BfAW/SST Checked By LJS ®riper Holocene Drilling Inc. Drilling Hollow Stem Auger Method Surface Elevation (ft) 28 Vertical Datum NAVD88 Hammer Data 140 (Ibs) / 30 (in) Drop Drilling Diedrich D50 Truck Rig Equipment Easting (X) Northing (Y) System Datum Groundwater Depth to Date Measured Water (ftl Elevation (ftl Notes: See Remarks ( i i 1 i l 1 i l 1 l l l i Li i 1 s ° s 'o 's �o `'s Elevation (feet) cWi+ o cNi� o <„ o o, o Depth (feet) FIELD DATA Graphic Log Group Classification Fines Content (% ) Interval Recovered (in) o o m Collected Sample Sample Name Testing Water Level MATERIAL15 DESCRIPTION „S NE i U REMARKS 12 3 AC \2 inches asphalt concrete walkway J J62 0 0 4 2 3A SM - Brown silty fine to medium sand (very loose, moist) (alluvium) - 1 12 18 1 18 118 I 12 18 6 4 10 10 12 2 %F 5 6 SA 8A SM Brown Silty fine to medium sand (loose, moist) (alluvium) — - Grades to wet _ Grades to medium dense with trace organic matter (small roots) = = — — 33 33 43 47 Groundwater observed at 12 feet at time of drilling I aa Mc ML _ Light gray silt with trace horizontally oriented organic matter (fine fibrous wood fragments) - (soft, moist) (alluvium) - 60 ill 12 118 23 9 10 SP-SM _ Gray fine to coarse sand with silt (medium dense, _ wet) (alluvium) = 26 10 Driller indicated different drilling J18 37 11 SAND STONE Sandstone: white, visuallyfresh, finegrained — (Puget Group Tiger Mountain formation) — conditions at approximately 34 feet Note: See Figure A-1 for explanation of symbols. Log of Boring B-2 GEOENGINEERS„g Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-3 Sheet 1 of 1 L L C11 CA C L C J ` Li 4 l i L I 21943-001-00 SST:LJS 04-28-2015 ti-V 321f10IA Sl1fS321 SISK1VNV 3A3IS PERCENT PASSING BY WEIGHT 100 90 80 70 60 50 40 30 20 10 0 U.S. STANDARD SIEVE SIZE 3 ' 1.5" 3/4" 3/8" #4 # 10 #20 #40 #60 #100 #200 1000 100 4 � 10 1 GRAIN SIZE IN MILLIMETERS 01 0.01 0.001 BOULDERS COBBLES GRAVEL SAND COARSE FINE COARSE MEDIUM FINE SILT OR CLAY SYMBOL EXPLORATION NUMBER DEPTH (ft) USCS SOIL CLASSIFICATION B-2 B-1 17.5 10 Gray silty sand (SM) Brown silty sand (SM) • APPENDIX B Permit Level Design Drawings 1 1 1 1 3 3 3 j P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETs.owc\TA6::COVER SHEET MODIFIED BY TMICHAUD ON JUN II, 2015 - 8.59 5133rd St 4 S <445 FOSTER Pe r �371h St i t V°Jm P v 6 S 140th 5t5 140th St it Showalter Meddle School rl Foster Nigh School S 144th St 5t S 160th St S 146th 5t 0 5 150th St Soutryn 5 156th St 4 4 5 164th 5t 5 166th St e >+°. s' en. h� �P R aS y 4' S 139th St 00 # Crystal Springs Park N 3 n:' VICINITY MAP Foster Goff links 4 �9i A Nf D 4 S 144th St 4 a 0 D S 147th 5t 4 Y N 4 0th 51 S152nd St sew. LD SCHNIEDER GREEN RIVER BANK REPAIR TUKWILA, WASHINGTON BLACK RIVER 5 143,a 5t JUNCTION 5 144, d Pl e 749th 5 5 130th St S Langston Rd S Langston Rd S 132ntyst s t31n0St S 133rd 5t Black River Quarry PROJECT SITE P4, Ton Oent Park rt S 153rd St 5 • 4, Tukwila Park S Tukwila • Southrenter Mall SCALE: 1"=100 Tukwila Pk 45 D i a i p C F 4 ral\ 4 Baker Blvd 5trander Blvd Treck Dr GRAPHIC SCALE 1000 1000 FEET a a 4'S 5 132nd St 5 132n 5 134th St S 13St11 Sr CD ♦ Black River Riparian Forest and Wetland v s5 SW 16th St SW 27u14. 0 D 5 O SHEET INDEX: VICINITY MAP AND SITE MAP 2 NOTES AND SPECIFICATIONS $ SITE PLAN 4 CROSS —SECTIONS 5 DETAILS SITE MAP SCALE: 1 "=400' GRAPHIC SCALE 400 400 FEET FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk R DESIGNED _ LJS ___ DATE 05/27 15 DRAWN TJM 11 CHECKED JMA FILE NO. 21493-001 —01 j SCALE AS NOTED III REVISED: 00/00/00 �pSEPI/ S,T GEOENGINEERS_..0 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON VICINITY MAP AND SITE MAP SHEET 1 GENERAL NOTES: 1. THESE DESIGNS AND DRAWINGS HAVE BEEN PREPARED FOR THE EXCLUSIVE USE OF LD SCNEIDER, AND THEIR AUTHORIZED AGENTS. NO OTHER PARTY CAN RELY ON THE PRODUCT OF OUR SERVICES UNLESS GEOENGINEERS INC. (GEOENGINEERS) AGREES IN WRITING IN ADVANCE OF SUCH USE. 2. 3. THE DRAWINGS CONTAINED WITHIN SHOULD NOT BE APPLIED FOR ANY PURPOSE OR PROJECT EXCEPT THE ONE SPECIFIED. THESE DESIGNS AND DRAWINGS ARE COPYRIGHTED BY GEOENGINEERS, INC. ANY USE, ALTERATION, DELETION, OR EDITING OF THIS DOCUMENT WITHOUT EXPLICIT WRITTEN PERMISSION FROM GEOENGINEERS IS STRICTLY PROHIBITED. ANY OTHER UNAUTHORIZED USE OF THIS DOCUMENT IS PROHIBITED. 4. THE CONTRACTOR SHALL CONSTRUCT THE PROJECT IN ACCORDANCE WITH THE PLANS STAMPED "APPROVED FOR CONSTRUCTION" THESE PLANS WILL BE PROVIDED TO THE CONTRACTOR BY THE ENGINEER OR PROJECT INSPECTOR PRIOR TO CONSTRUCTION. WORK SHALL NOT BE INITIATED WITHOUT THE PLANS APPROVED FOR CONSTRUCTION. 5. THE DESIGNS DEPICTED HEREIN ARE APPROXIMATE AND ARE INTENDED TO EXPRESS THE OVERALL DESIGN INTENT OF THE PROJECT. THESE DESIGNS MAY NEED TO BE ADJUSTED IN THE FIELD DURING CONSTRUCTION IN ORDER TO MEET THE SPECIFIC SITE CONDITIONS AND INTENDED FUNCTION. THESE RIVER IMPROVEMENTS HAVE BEEN DEVELOPED WITH THE UNDERSTANDING THAT A QUALIFIED GEOENGINEERS ENGINEER AND/OR SCIENTIST BE ON -SITE TO PROVIDE CONSTRUCTION GUIDANCE WHILE THE PROJECT IS CONSTRUCTED. 6. CONDITIONS CAN CHANGE AND THESE DESIGNS ARE BASED ON CONDITIONS THAT EXISTED AT THE TIME THE DESIGN WAS PERFORMED. THE RESULTS OF THESE DESIGNS MAY BE AFFECTED BY THE PASSAGE OF TIME, BY MANMADE EVENTS SUCH AS CONSTRUCTION ON OR ADJACENT TO THE SITE, OR BY NATURAL EVENTS SUCH AS FLOODS, EARTHQUAKES, SLOPE INSTABILITY OR GROUNDWATER FLUCTUATIONS. ALWAYS CONTACT GEOENGINEERS BEFORE APPLYING THESE DESIGNS TO DETERMINE IF THEY REMAIN APPLICABLE. 7. THESE PLANS AND ELECTRONIC DRAWINGS ARE BASED ON WASHINGTON STATE PLANE NORTH COORDINATES US FEET AND A NORTH AMERICAN VERTICAL DATUM OF 1988 US FEET. ELEVATIONS AND NORTHINGS AND EASTINGS WITHIN THIS PLANSET ARE BASED ON THESE DATUMS. CONSTRUCTION NOTES: 1. CONTRACTORS WORKING WITHIN THE PROJECT BOUNDARIES ARE RESPONSIBLE FOR COMPLIANCE WITH ALL APPLICABLE SAFETY LAWS. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL BARRICADES, SAFETY DEVICES AND CONTROL OF TRAFFIC WITHIN AND AROUND THE CONSTRUCTION AREA. 2. MATERIAL AND WORKMANSHIP FURNISHED ON OR FOR THE PROJECT MUST MEET THE MINIMUM REQUIREMENTS OF PROJECT PERMITS, APPROVING AGENCIES, SPECIFICATIONS AS SET FORTH HEREIN, OR WHICHEVER IS MORE RESTRICTIVE. 3. THE CONTRACTOR SHALL INSTALL AND MAINTAIN APPROPRIATE SEDIMENT CONTROL DEVICES THROUGHOUT THE WHOLE PROJECT SITE, INCLUDING THE CONSTRUCTION STAGING AREA AND STOCKPILE AREA THROUGHOUT THE PROJECT'S CONSTRUCTION. TEMPORARY CONSTRUCTION AND PERMANENT EROSION CONTROL MEASURES SHALL BE DESIGNED, CONSTRUCTED AND MAINTAINED IN ACCORDANCE WITH APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS. 4. CONSTRUCTION SHALL OCCUR DURING THE APPROVED WDFW FISH WINDOW FOR THE PROJECT AREA. 5. DISCHARGES ENTERING ACTIVE STREAMS ON -SITE SHALL SATISFY ALL STATE AND FEDERAL STANDARDS AND PROJECT PERMIT REQUIREMENTS FOR CONTAMINANTS AND TURBIDITY. SPECIFICATIONS: A. REFERENCED SPECIFICATIONS ARE FROM THE 2014 VERSION OF THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION. MATERIALS: A. 1. 2. B. 1. RIVERBANK FILL RIVERBANK FILL SHALL CONSIST OF WELL GRADED SAND AND GRAVEL CONFORMING TO EITHER WSDOT STANDARD SPECIFICATION 9-03.10 "AGGREGATE FOR GRAVEL BASE", 9-03.12(2) "GRAVEL BACKFILL FOR WALLS", 9-03.13(1) "GRAVEL BORROW", 9-03.13(2) "SELECT BORROW", OR OTHER MATERIALS AS APPROVED BY THE GEOTECHNICAL ENGINEER. NATIVE ALLUVIUM FROM THE EXISTING RIVERBANK MAY BE INCORPORATED INTO THE RIVERBANK FILL PROVIDED THAT THE ALLUVIUM CONTAINS LESS THAN 30 PERCENT FINES (MATERIAL PASSING THE NO. 200 SIEVE) BY WEIGHT OR AS APPROVED BY THE GEOTECHNICAL ENGINEER. RIVERBANK FILL SHALL BE FREE OF ORGANICS OR OTHER DELETERIOUS MATERIALS. DRAINAGE ROCK DRAINAGE ROCK SHALL MEET WSDOT STANDARD SPECIFICATION 9-03.12(2) "GRAVEL BACKFILL FOR WALLS." C. DRAIN PIPE 1. DRAIN PIPE SHALL CONSIST OF 4-INCH SCHEDULE 40 PVC PIPE. THE PIPE SHALL BE SOLID OR PERFORATED AS INDICATED ON THE PROJECT PLANS. THE PIPE AND CONNECTIONS SHALL MEET AASHTO SPECIFICATION M 278. PIPE CONNECTIONS AND DETAILING SHALL BE IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. 2. PERFORATED DRAIN PIPE INSTALLED PARALLEL TO THE SLOPE AND SHALL CONNECT TO SOLID DRAIN D. 1. PIPES (OUTLET DRAINS) THAT DAYLIGHT TO THE SLOPE FACE. SOLID DRAIN PIPES SHALL BE SPACED NO MORE THAN 20 FEET APART. SOLID DRAIN PIPES SHALL DISCHARGE ON AN EROSION PROTECTION PAD OR EXTEND TO THE BASE OF THE EXISTING SLOPE. EROSION PROTECTION PADS SHALL BE CONSTRUCTED OF MATERIAL CONFORMING TO WSDOT STANDARD SPECIFICATION 9-03.9(2) "PERMEABLE BALLAST'. THE EROSION PROTECTION PADS SHALL BE FIELD FIT BY THE ENGINEER AT THE DISCHARGE LOCATIONS AND SHALL HAVE A MINIMUM THICKNESS OF 6-INCHES, MINIMUM LENGTH (PARALLEL TO SLOPE) OF 2 FEET, AND MINIMUM WIDTH (PERPENDICULAR TO SLOPE) OF 1 FOOT. NON -WOVEN GEO-TEXTILE NON -WOVEN GEO-TEXTILE SHALL MEET WSDOT STANDARD SPECIFICATION 9-33.1 "GEOSYNTHETIC MATERIAL REQUIREMENTS" FOR NON -WOVEN GEO-TEXTILES USED FOR SEPARATION. E. RECYCLED MATERIAL 1. RECYCLED MATERIAL SHALL NOT BE USED IN AGGREGATES OR FILL. F. 1. TOPSOIL TOPSOIL SHALL CONSIST OF A COMMERCIALLY AVAILABLE 3-WAY MIXTURE CONSISTING OF LOAM SOIL, ORGANICS AND COMPOST PASSING )6-INCH SIEVE. G. EROSION CONTROL BLANKET AND STRAW WATTLES 1. EROSION CONTROL BLANKET SHALL COMPLY WITH WSDOT STANDARD SPECIFICATION 9-14.5(2)D "BIODEGRADABLE EROSION CONTROL BLANKET FOR DITCHES. THE EROSION CONTROL BLANKET SHALL BE 100-PERCENT BIODEGRADABLE COIR WITHOUT MESH BACKING. THE EROSION CONTROL BLANKET SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. 2. STRAW WATTLE OR SIMILAR SHALL BE 100% BIODEGRADABLE. STRAW WATTLES SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. EXECUTION: A. SUBGRADE PREPARATION 1. SUBGRADES SHALL BE CLEARED AND GRUBBED. REMOVE BRUSH, SOD, OR OTHER ORGANIC OR DELETERIOUS MATERIALS PRIOR TO THE PLACEMENT OF FILL. SOFT AREAS SHALL BE OVEREXCAVATED AND REPLACED, AS DIRECTED BY GEOTECHNICAL ENGINEER. 2. SUBGRADE SHALL BE APPROVED BY GEOTECHNICAL ENGINEER. SUBGRADE SOILS SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION BEFORE CONSTRUCTION PROCEEDS. SUBGRADE MATERIALS NOT MEETING GEOTECHNICAL ENGINEER'S APPROVAL SHALL BE REMOVED AND REPLACED WITH RIVERBANK FILL AT DIRECTION OF GEOTECHNICAL ENGINEER. 3. OVEREXCAVATED AREAS SHALL BE REPLACED WITH COMPACTED RIVERBANK FILL MATERIAL. B. SLOPE PREPARATION 1. EXISTING SLOPES SHALL BE RE -GRADED AS REQUIRED TO INSTALL SPECIFIED IMPROVEMENT AND TO MAINTAIN A SAFE WORK ZONE. THE CONTRACTOR IS RESPONSIBLE FOR MAINTAINING A SAFE WORK ZONE AND COMPLYING WITH THE PROVISIONS OF TITLE 296 WASHINGTON ADMINISTRATIVE CODE (WAC), PART N, "EXCAVATION, TRENCHING AND SHORING." 2. FILL PLACED ON OR ADJACENT TO SLOPES SHALL BE PLACED ON HORIZONTAL BENCHES CUT INTO THE EXISTING SLOPE. 3. BENCHES SHALL EXTEND A MINIMUM OF 2-FEET HORIZONTALLY INTO THE SLOPE AND MAY BE CUT IN STAGES AS THE FILL PROGRESSES. C. FILL PLACEMENT AND COMPACTION 1. FILL MATERIAL SHALL BE PLACED IN LOOSE LIFTS NOT EXCEEDING 12-INCHES AND COMPACTED USING EQUIPMENT DESIGNED FOR SOIL COMPACTION. 2. FILL SHALL BE UNIFORMLY COMPACTED TO A MINIMUM 90 PERCENT OF MAXIMUM DRY DENSITY (MDD) AS DETERMINED BY ASTM D-1557. D. SITE REVEGETATION 1. TOPSOIL SHALL BE LOOSELY PLACED ABOVE THE RIVERBANK FILL TO A DEPTH OF 12 INCHES. THE FINISH GRADE SHALL BE TAMPED FIRM AND PROTECTED FROM EROSION. 2. THE EROSION CONTROL BLANKET SHALL BE SHINGLED OR PLACED IN A MANNER SUCH THAT RIVER FLOWS AND WIND DO NOT PEEL UP THE FABRIC. THE EROSION CONTROL FABRIC SHALL BE ANCHORED FOLLOWING THE MANUFACTURER'S INSTRUCTION. 3. NATIVE PLANTS, IDENTIFIED IN THE PLANT SCHEDULE, SHALL BE INSTALLED FOLLOWING THE LAYOUT PROVIDED BY THE GEOENGINEERS BIOLOGIST. PLANTS SHALL BE INSTALLED THROUGH THE EROSION CONTROL FABRIC BY CUTTING THE FABRIC TO THE MINIMUM NECESSARY TO INSTALL THE PLANTS. E. SITE MAINTENANCE AND MONITORING 1. THE SITE WILL BE MAINTAINED BY THE OWNER INTO PERPETUITY AND IN COMPLIANCE WITH THE PROJECT PERMITS. 2. THE SITE WILL BE MONITORED FOR A PERIOD OF FIVE YEARS FOLLOWING PLANT INSTALLATION AS SPECIFIED IN THE DESIGN AND ANALYSIS REPORT BY GEOENGINEERS OR AS REQUIRED BY THE PROJECT PERMITS. ANTICIPATED MATERIAL SCHEDULE APPROXIMATELY 420 YD3 OF CUT AND FILL: • -160 YD3 OF NATIVE MATERIAL TO REMAIN ON SITE. • -160 YD3 OF IMPORTED RIVERBANK FILL. • -96 YD3 OF IMPORTED TOPSOIL. • -3 YD3 OF 1-INCH DRAIN ROCK. • -1 YD3 OF IMPORTED OUTFALL PROTECTION. FOR PERMIT REVIEW - NOT FOR CONSTRUCTION Description REVISION PER AGENCY COMMENTS Date By Chk Rev DESIGNED LJS 7-22-15 ,TJM TAB WS 1 DRAWN TJM DATE 05/27/15 FILE NO. 2�493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 GEOENGINEERS 600 Stewart Street, Suite 1700 P: 206-728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON NOTES AND SPECIFICATIONS SHEET 2 fl J J n L n .J n LJ n r� .J LJ • -II LJ ,I U L...J P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETS.DWG\TAB:PLAN VIEW MODIFIED BY TMICHAUD O } \\ OHWM OHWM ASPHALT TRAIL 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER COMMERCIAL BuILOING LEGEND B-14- BORING LOCATIONS. —?S EXISTING CONTOURS PROPOSED BANK LINES OHWM ORDINARY HIGH WATER MARK LIMITS OF WORK SILT FENCE \\ BORING LOGS PROVIDED IN ACCOMPANYING REPORT (GEOENGINEERS 2015) VERTICAL DATUM: NAVD88 OHWM O STONE BENCH OHWM GREEN RIVER OHWM EL=10.0' OHWM OHWM a: 0b_rk- v OHWM OHWM STONE BENCH 24" SYCAMORE 34 SYCAMORE PLAN VIEW SCALE: 1"=10' SCALE FEET OUTLET DRAIN (TYP.) OHWM x BOTTOM OF FILL SLOPE r- SILT FENCE OHWM x O x zOMNM PARK \NG LOT 30" SYCAMORE OHWM OH'NM 0 15 — 2 _ TOP OF EXISTING SLOPE ONWM 24" SYCAMORE 41" SYCAMORE PROTECT TREES PER CITY REQUIREMENTS (TYP.) FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk Rev DESIGNED WS DRAWN TJM DATE 05/27/15 FILE NO. 21493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 00/00/00 GEOENGINEERS_.0 600 Stewart Street, Suite 1700 P: 206-728-2674 Seattle, WA 98101 E: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON SITE PLAN SHEET 3 J P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETS.DWG\TAB:SECTIONS MODIFIED BY 'ammo ON JUL 22, 2015 - 1 5 SCALE 0 5 FEET 30 24" SYCAMORE (PROTECT TREE PER GEOENGINEERS) I---- PARKING LOT 20 — 10 — 1 ------------------- LANDWARD LIMITS OR WORK 1 EXISTING 1 H ASA TRAILPHLT SEE ANCHOR TRENCH DETAIL CUT AS REQUIRED FOR SAFETY AND STABILITY TOP SOIL ,— EXISTING GRADE 25 RIVERBANK FILL NATIVE VEGETATION (TYP.) EROSION CONTROL FABRIC OUTFALL PROTECTION PER MATERIAL NOTE C-2 BASE FLOOD SEE DRAIN DETAIL J OUTLET DRAIN — SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) — 30 ELEVATION —20 SILT FENCE (WATERWARD LIMITS OF WORK) OHWM 0 10 20 30 30 30" SYCAMORE (PROTECT TREE PER GEOENGINEERS) PARKING LOT ----------------- 20 — 10 - 0 SECTION 40 Distance (Feet) 50 60 A HORIZONTAL SCALE: 1"=5' VERTICAL SCALE 1"=5' LANDWARD LIMITS OR WORK 1 SEE ANCHOR TRENCH DETAIL EXISTING ASPHALT TRAIL CUT AS REQUIRED FOR SAFETY AND STABILITY SEE DRAIN DETAIL C-2 NATIVE VEGETATION (TYP.) EXISTING GRADE TOP SOIL 70 80 30 RIVERBANK FILL — EROSION CONTROL FABRIC — BASE FLOOD ELEVATION — • — - — - — - — - — - — - — - — - — - — 20 OUTFALL PROTECTION PER 2.5 MATERIAL NOTE C-2 11 SILT FENCE 2q+{� (WATERWARD LIMITS _ OF WORK) SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) OHWM 10 20 SECTION 30 40 Distance (Feet) 50 B HORIZONTAL SCALE: 1' 5' VERTICAL SCALE 1" 6 C-2 60 70 80 10 0 10 0 85 .15 FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date By Chk Rev REVISION PER AGENCY COMMENTS 7-22-15 TJM TAB LJS DESIGNED LJS DRAWN TJM DATE 05/27/15 FILE NO. 21493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 GEOENGINEER_ 600 Stewart Street, Su'te 1700 P: 206-728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON CROSS -SECTIONS AND DRAIN DETAIL SHEET 4 P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETS.DWG\TAB:DETAILS MODIFIED BY TMICHAUD ON JUL 21, 2015 - 4" SCH40 PERFORATED PVC DRAIN PIPE EL. 15.0' RIVERBANK FILL 12" DRAIN DETAIL NON -WOVEN GEOTEXTILE SOLID SCH40 PVC OUTLET DRAIN 2% NATIVE SOIL NOT TO SCALE A\ JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATTACH FABRIC TO POSTS. T -- ..lJl�t1�11T 6' MAX. LJ POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBLE Recommended Planting Schedule Estimated Common Name Scientific Name Size Spacing Quantity 12 Black cottonwood Populus balsamifera 6 - 8 feet in height 10 feet o.c. 14 Western red cedar Thuja plicata 6 - 8 feet in height 10 feet o.c. 12 Big leaf maple Acer macrophyllum 6 - 8 feet in height 10 feet o.c. 12 Pacific dogwood Corpus nutalli 6 - 8 feet in height 10 feet o.c. 40 Vine maple Acer clrcinatum 6 - 8 feet in height 5 feet o.c. 40 Oceanspray Holodiscus discolor 24-inch in height 5 feet o.c 40 Snowberry Symphoricarpos albus 24-inch in height 5 feet o.c 40 Western serviceberry Amelanchier alnifolia 24-inch in height 5 feet o.c 40 Red osier dogwood Cornus sericea 24-inch in height 5 feet o.c PLANT SCHEDULE 2"x2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC MINIMUM 4"x4" TRENCH BACKFILL TRENCH WITH NATIVE SOIL OR 3/4"-1.5" WASHED GRAVEL 2"z4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT SILT FENCE DETAIL NOT TO SCALE vai EXCESS SOCK MATERIAL, DRAWN IN AND TIED OFF AT STAKE (TYP.) DISTURBED AREA PLAN VIEW 10' (MAX) DISTURBED AREA PROTECTED AREA SECTION (SHOWN AS SLOPE PROTECTION) 10' - 0" ® 30" ANGLE EACH END TO PREVENT FLOW AROUND (TYP.) 2"X2" X 3' WOODEN STAKE COMPOST SOCK SEE NOTE 1 CONTOUR LINE (TYP.) 2"X 2"X 3' WOODEN STAKE, SPACED EVERY 3' O.C. (TYP.) DETAIL NOTES: 1. COMPOST SOCK SHALL BE IN ACCORDANCE WITH STANDARD SPECIFICATION 9.14.4(9). COMPOST SOCK SHALL BE A MINIMUM OF 10" IN DIAMETER OR SIZED TO SUIT CONDITIONS AS SPECIFIED BY THE ENGINEER. 2. ALWAYS INSTALL COMPOST SOCK PERPENDICULAR TO SLOPE AND ALONG CONTOUR LINES. 3. REMOVE SEDIMENT FROM THE UP SLOPE SIDE OF THE COMPOST SOCK WHEN ACCUMULATION HAS REACHED 1/2 OF THE EFFECTIVE HEIGHT OF THE COMPOST SOCK. 4. MAY BE USED IN PLACE OF FILTER FENCE FOR PERIMETER CONTROL. STRAW WATTLE DETAIL NOT TO SCALE EROSION CONTROL FABRIC LOOSEN AND/OR CUT CIRCLING ROOTS IN ROOT BOUND CONTAINERS BEFORE PLANTING BREAK UP SIDES AND BOTTOMS OF PLANTING PIT TO ALLOW FOR ROOT PENETRATION COMPACT SUBGRADE BELOW ROOT BALL TYPICAL PLANTING DETAIL FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date Q REVISION PER AGENCY COMMENTS By Chk 7-22-15 TJM TAB Rev US DESIGNED US DRAWN TJM DATE 05/27/15 FILE NO. 21493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 GEOENGINEERZ 600 Stewart Street, Suite 1700 P: 206-728-2674 Seottle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON DETAILS SHEET 5 APPENDIX C Project Value Documentation • J L J LJ J '1 J J 1 J �J LB Schneider Green River Bank Repair - Project Value Documentation 14900 Interurban Avenue South Tukwila, Washington Description Description of Quantity QTY per foot of repair Unit Unit Cost (Total + 0&P) Total for Foot of Repair Project Total Based on 160 Feet of Repair Excavation and Haul Riverbank Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY _ $17.00 $0.00_ $0.00 Subtotal Subsurface Drainage Fabric Laid in Trench RS Means 1.3 SY $2.42 $3.15 $503.36 Drainage Material RS Means 0.22 CY $34.00 $7.48 $1,196.80 6-in PVC Perforated RS Means 2 LF $14.45 $28.90 $4,624.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0.126 TON $48.00 $6.05 $967.68 Subtotal $42.43 $6,788.48 Foundation Preparation Foundation Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY $17.00 $0.00 $0.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0 TON $48.00 $0.00 $0.00 Subtotal $0.00 $0.00 Fill Placement and Compaction Gravel Borrow Including Haul and Compaction Bid Tab 1075 from B&D Levee Project 5.53 TON $20.00 $110.60 $17,696.00 Geo-Grid Soil Reinforcement RS Means 0 SF $0.81 $0.00 $0.00 Jute Mesh Bid Tab 8025 from B&D Levee Project 0 SY $1.30 $0.00 $0.00 Subtotal $110.60 $17,696.00 Erosion Control, Surface Treatments, and Plantings TESC Tab Schedule VII B&D Levee 1 LF of River $51.28 $51.28 $8,204.80 _Bid Landscaping Bid Tab Schedule VIII B&D Levee 1 LF of River $100.00 $100.00 $16,000.00 Subtotal $151.28 $24,204.80 Mobilization, Contingency, Misc., and Totals Total Unit Costs $262 $41,901 Mobilization Assumed Values 10.0% LS $26 $4,190 Contingency Assumed Values 15.0% LS $39 $6,285 Miscellaneous Costs Assumed Values 10.0% LS $26 $4,190 Sales Tax Washington State 9.5% LS $25 $3,981 Estimated Totals $378 $60,547 APPENDIX D Trail Easement Agreement ' - 4gr •••• (.1.! „ • • ' '';',!;%:"1/01" :••••, • 1 ,.; • • . . • ir • • fl • • • . *.-1 • • " '• EASEMENT • I . . • •.. . • . ... . -".. . .. . . . . . . , . . • . . - • • PropeSed:t-2B49 ' • 14F:#78417SMP- - • , THIS INSTRUMENT maden this day of 044-,14-0111( ,1990. ., • by.Gary A. NiIsen Sr. and L.O. Schneider (the "Grant° sw).'in favor of CITY Or. •: - TUKWILA, a municipal corporation of King County, State pf Washington (the %ranee"). , • . - • WITNESSETH . . Grantees, for and in consideration of the sum of one dollar (1.00) and -other valuable consideration, receipt of which is acknowledged, Grantors grants, :con, • .veys., and -conf-rms to Grantee, its successors and assigns, a perpetual Mil -exclusive easement -for public •aceeis for the purpose of constructing and operating'a recreational trail open to the public, and related construction and improvements, across and upon the property described on the attached "Exhibit A" and further shown on the map attached as "Exhibit B". Grantee shall have the right without prior institution of suit or proceeding at law, at such time as may be deemed appropriate by Grantee. to enter upon said property for the purpose of operating, maintaining, repairing, replacing.or re- • -1 constructing a public. recreational trail and related improvements, without incur- . ring legal obligations or liability therefor; provided, said operating, -Maintain- ing, repairing, replacing, or reconstructing of a.public recreational trail or related improvements shall be accomplished in such a manner that private improve- ments shell not be disturbed or destroyed. and Grantors shall not be excluded from , such -easement property and shall have unlimited right to use said easement property for any lawful purposes not inconiistant with the rights of grantee. In the event they are disturbed or destroyed, they will be replaced in as good a condition. . as,they.were immediately before the property was entered upon by Grantee. This .shall be a covenant running with the land forever and shall be binding on Grantors successors; heirs and assigns. 9-1 ' 71 • By: 1% EXCISE TAX NOT REQUIRED Xing Co flecordz: . . •• . "Da.ec. -,A7 • C) co EXHIi3TT A Thelpede'strian access easement as, described in the easement agreement shall:be;: from the ordinary•h•i•gh water mark to a point 40 feet west of said'ordinary high ' •.water'mark over.'all of the •following parcels, of land: '• LEGAL. DESCRIPTIONS: • That portion of Tract.1, interurban Addition to Seattle, according to the plat.recorded in Volume 10 ornate, page 55, records of King County, Washington, lying southerly of a line which extends northeasterly,•perpen- dicular with the westerly line of said tract, from a point•on said westerly.' line which is 685 feet southeasterly from the northwest corner of. said 'tract; and lying northerly of a line which extends northeasterly, perpen- dicular with the westerly line of said tract, from a point on said westerly line'which is 1555 feet southeasterly from the northwest corner.of said tract;'ALSO that portion of the vacated Puget Sound Electric Railway R/W adjoining'thereto lying southeasterly of S. 149th St. as conveyed by Puget•Sound Power and Light Co. to the City of Tukwila by deed dated October 25, 1965 and filed under Auditor's File No. 6557639; and Lying northwesterly of a line which extends southwesterly, perpendicular with the easterly line of said P.'S. E. R/W, which is also the westerly line of said Tract 1, lnterurban Addition, from a point on said westerly'line which is 1555 feet southeasterly from the northwest corner of said tract. �3�wRFW�i•14�ON7.'itX)- r• 1 r' r • r• 1. • .•;:y : •-• • - • ff,.,1 „qt. • „ • 14 • . • % - • , . *•!••••,. • • , • , . . • r ' -t-iTAtE OFAASHINGTON) .') st. - • ' COUNTY OF KING - ) •;: ' • • .* .; : • '•••••••,14•4:,-.4,-.••;14.••:;••••••i!•:;•.1.(,••044-to,v,....„4;,.,g, j..„ . . ',. . .-. On this itlk- day Of am..../.."—e....A..A4 / 1 /leg -Ism beforeme personally ,--+cl* -,.• . . appeared _.;i7 A, ,,,..c...,,/,,..„_,___ALIA_ • e•-• ; ' ' • • '• - — and. • • ' e.-- 4- AA ./. . r1 • ,... ... j..4,-,-,7 ,1"......L.p...-- , - . ' to. Me known a be thie• i'l•_,;. -‘_.•-•t-k•—•9 -, - 1. 7, • ., of- 4.-1.--y....A...... 1.2—A._ — A), ..9_,,,..91z.....--y•y0 . . 7 ;:-.5.7 . i t n r A — .,the•individuals that executed the foregoing instrument, nd acknowledged the' said . • >•instrument to be the free and voluntary act and deed of said individuals fp;:the LI • • . _uses and purposes mentioned therein, and on oath stated that they were authorized -1 to execute the'said instrument. L_J ' 71 , fl' r ,;."01,..',13,1* • r ( NOTARY PUBLI in and fgf then.S4te of Wash- ington, res • ng at 194, -2- • • • . . - r • . • r.::(1v! • • .4 V.Arrpit .411.; 4 , " • , 4 .;,1"., % 1 6.! • V. A iA,1 - ',• • , • • •1!.5'440 . . J • . 14, ' • . .• ' • • .., • • ir r ;* ' • • - ; • • • 10 411- ."! • CO CO uJ I-1 . • ••-••• P3 0 0 e 0 re t • ec 0 tu cc, 0 no • ; A • 4 . • ti • • •-• . I I ...Urine • I .zcirleA• • ;•,.. ,••••• • •,t-f• • ' • 0-• •r„e • 4 6,, I r. • • It' LJ Ng: •43,;44,.'s • 4•!.: . • , • . r 1; • ••• • • , • • • . • t • L _J r; fl I fl 6-1 n. .• • ' • . CO fl• —7 I • • . d• • ! - , - - • t :,••••„.;, ' d FILED. for Reord at eguest of ._,,• • ...... .-.:* •." . • • W.•:A.,'';‘ • '-;• . . .0 • .: • • •••-r:C. ':• ;°.• : • • = a 7 . = • n•-• . . • -.. • • ...::1!:.-T.;.-1141`41 ".•;r ' . • , • • • • ,• . • • • ' -•- • ‘. cn. • • • • .• !.t.• • • • t f 11 eity o f .J u11wiea Department Of Community Development AFFIDAVIT OF DISTRIBUTION I, Valerie Lonneman, HEREBY DECLARE THAT: Notice of Application Notice of Decision Notice of Public Hearing Notice of Public Meeting V `, Determination of Non- Significance Mitigated Determination of Non- Significance Determination of Significance & Scoping Notice Short Subdivision Agenda Notice of Application for Shoreline Mgmt Permit Shoreline Mgmt Permit Board of Appeals Agenda Packet Board of Adjustment Agenda Packet Official Notice Notice of Action Other: Was mailed to each of the addresses listed/attached on this 17 day of August, 2015 Project Name: Green River Bank Erosion Repair Project Number: E15-0007 (SEPA) Associated File Number (s): L15-0032 (Shoreline) Mailing requested by: Valerie Lonneman r Mailer's si nature: W:\USERS\VALERIE\AFFIDAVIT OF DISTRIBUTION.DOC laura.murphy@muckleshoot.nsn.us, Muckleshoot Tribe Karen.Walter@muckleshoot.nsn.us, Muckleshoot Tribe mike.middleton@muckleshoot.nsn.us, Muckleshoot Tribe james@duwamishcleanup.org, Duwamish Tribe Kurn Schneider, Owner (9vt ka t�) tannister@geoengineers.ctim, Thomas Bannister, Applicant Larry.Fisher@dfw.wa.gov, Washington Department of Fish and Wildlife sepaunit@ecy.wa.gov, State Department of Ecology, SEPA Division Christie.Most@kingcounty.gov, King County Assessor W:\USERS\VALERIE\AFFIDAVIT OF DISTRIBUTION.DOC CITY OF TUIKWILA Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 AFFIDAVIT OF OWNERSHIP AND HOLD HARMLESS PERMISSION TO ENTER PROPERTY STATE OF WASHINGTON COUNTY OF KING The undersigned being duly sworn and upon oath states as follows: 1. I am the current owner of the property which is the subject of this application. 2. All statements contained in the applications have been prepared by me or my agents and are true and conect to the best of my knowledge. 3. The application is being submitted with my knowledge and consent. 4. Owner grants the City, its employees, agents, epgineers, contractors or other representatives the right to enter upon Owner's real property, located at i'i 11 U RZAN AVE , ''-1 for the purpose of application review, for the limited time necessary to complete that purpose. 5. Owner agrees to hold the City harmless for any loss or damage to persons or property occurring on the private property during the City's entry upon the property, unless the loss or damage is the result of the sole negligence of the City. 6. Non -responsiveness to a City information request for ninety (90) or more days, shall be cause to cancel the application(s) without refund of fees. EXECUTED at 01-a1•1 i X I (city), A Z (state), on Q u,JG , 20 /5— KQRA (Print Nameg) �� 3ZNcO0 Z 1 (;it' V Sf 1 ttOOX 4-z (Address) zze;„ (Phone Number) 2;;;/-•• C:01/ (Signature) (kW icV't to me known to be the individual who executed the foregoing instrument and acknowledged that he/she signed the same as his/her voluntary act and deed for the uses and purposes mentioned therein. SUBSCRIBED AND SWORN TO BEFORE ME ON THIS < DAY OF J U N-e' , 20 I S On this day personally appeared before me LAURA TUCKER Notary Public- State dAdzons MARICOPA COUNTY My Commission Expires March 31, 2010 NOTARY PUBLIC in and for the State of Washington ARf.ZL - residing at M Ri Copy [ nuNt� My Commission expires on MClP-Oh �l 1 2Dt% \\Deptstore\City Common\Tcri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.Docx C='-'.of Tukwila ESA Screening Checklist Part A: Please review and answer each question carefully. Consider all phases of your project including, but not limited to, construction, normal operation, potential emergency operation, and ongoing and scheduled maintenance. Continue to the next question as directed for each No or Yes answer. 1-0 Will the project require any form of grading? Grading is defined as any excavating, filling, clearing, or creation of impervious surface, or any combination thereof, which alters the existing ground surface of the earth (TMC 18.06.370). Please mark the appropriate response. NO - Continue to Question 2-0 YES - Continue to Question 1-1 (Page 3) 2-0 Will the project require any form of clearing? Clearing means the removal or causing to be removed, through either direct or indirect actions, any vegetation from a site (18.06.145). Please mark the appropriate response. NO - Continue to Question 3-0 YES - Continue to Question 2-1 (Page 4) 3-0 Will the project require work, during any time of the project, below the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers or in wetlands? Ordinary high water mark is the mark that is found by examining the bed and banks of a stream and ascertaining where the presence and action of waters are so common and usual as to distinctly mark the soil from that of the abutting upland, in respect to vegetation (see TMC Chapter 18.06, Page 18-15). Please mark the appropriate response. NO - Continue to Question 4-0 YES - Continue to Question 3-1 (Page 5) 4-0 Will the project result in the processing or handling, storage, or treatment of hazardous substances? This does not include the proper use of fuel stored in a vehicle's fuel tank. Hazardous substances are any liquid, solid, gas, or sludge, including any material, substance, product, commodity, or waste, regardless of quantity, that exhibits the characteristics or criteria of hazardous waste as defined by Washington Administrative Code 173-303 (TMC 18.06.385). This includes fuel or other chemicals stored on -site during construction. Please mark the appropriate response. NO - Continue to Question 5-0 YES - Continue to Question 5-0 5-0 Will the project result in the withdrawal, injection, or interception of groundwater? Examples of projects that may affect groundwater include, but are not limited to: construction of a new well, change in water withdrawals from an existing well, projects involving prolonged construction dewatering, projects installing French drains or interceptor trenches, and sewer lines. For the purpose of this analysis, projects that require a geotechnical report pursuant to the requirements of TMC 18.45.060 or would require a geotechnical report if not exempt should answer Yes. Please mark the appropriate response. NO - Continue to Question 6-0 ✓ YES - Continue to Question 6-0 6-0 Will the project involve landscaping or re -occurring outdoor maintenance that includes the regular use o: fertilizers, pesticides, or herbicides? This does not include the one-time use of transplant fertilizers. Landscaping means natural vegetation such as trees, shrubs, groundcover, and other landscape materials arranged in a manner to produce an aesthetic effect appropriate for the use of the land (TMC 18.06.490). For the purpose of this analysis, this includes the establishment of new lawn or grass. Please mark the appropriate response. NO — Checklist Complete YES — Checklist Complete \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 2 (� \ of Tukwila ESA Screening Checklist Part B: Please answer each quesstion below for projects that include gradi: Review each question carefully, considering all phases of your project including, but not limited to construction, normal operation, potential emergency operation, and ongoing and scheduled maintenance. Continue to the next question as directed for each No or Yes answer. 1-1 Will the project involve the modification of a watercourse bank or bank of the Green/Duwamish or Black Rivers between the ordinary high water mark and top of bank? This includes any projects that will require grading on any slope leading to a river or stream, but will not require work below the ordinary high water mark. Work below the ordinary high water mark is covered in Part C. Please mark the appropriate response. NO - Continue to Question 1-2 ✓ YES - Continue to Question 1-2 1-2 Could the construction, operation, or maintenance of the project result in sediment transport off site or increased rates of erosion and/or sedimentation in watercourses, the Green/Duwamish rivers, or the Black River? Most projects that involve grading have the potential to result in increased erosion and/or sedimentation as a result of disturbances to the soil or earth. If your project involves grading and you have not prepared a Temporary Erosion and Sedimentation Control Plan specifically designed to retain 100 percent of the runoff (including during construction) from impervious surface or disturbed soils, answer Yes to this question. If your project is normally exempt under the Tukwila Municipal Code and would not require the preparation of a Temporary Erosion and Sedimentation Control Plan, BUT may still result in erosion or sediment transport off site or beyond the work area, answer Yes to this question. Please mark the appropriate response. NO - Continue to Question 1-3 1 YES - Continue to Question 1-3 1-3 Will the project result in the construction of new impervious surfaces? Impervious surfaces include those hard surfaces which prevent or restrict the entry of water into the soil in the manner that such water entered the soils under natural conditions prior to development; or a hard surface area that causes water to run off the surface in greater quantity or at an increased rate of flow from the flow presented under natural conditions prior to development. Such areas include, but are not limited to, rooftops, asphalt or concrete paving, compacted surfaces, or other surfaces that similarly affect the natural infiltration or runoff patterns existing prior to development (TMC 18.06.445). Please mark the appropriate response. NO - Continue to Question 2-0 (Page 2) YES - Continue to Question 1-4 1-4 Will your project generate stormwater from the creation of impervious surfaces that will not be infiltrated on site? For the purpose of this analysis, infiltration includes the use of a stormwater treatment and management system intended to contain all stormwater on site by allowing it to seep into pervious surface or through other means to be introduced into the ground. If your project involves the construction of impervious surface and does not include the design of a stormwater management system specifically designed to infiltrate stormwater, answer Yes to this question. Please mark the appropriate response. NO - Continue to Question 2-0 (Page 2) YES - Continue to Question 2-0 (Page 2) \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 3 / G' of Tukwila ESA Screening Checklist Part C: Please review each questiod below for projects that include clearing. tteview each question carefully, considering all phases of your project including, but not limited to construction, normal operation, potential emergency operation, and ongoing and scheduled maintenance. Continue to the next question as directed for each No or Yes answer. 2-1 Will the project involve clearing within 200 feet of the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? Please mark the appropriate response. NO - Continue to Question 3-0 (Page 2) ✓ YES - Continue to Question 2-2 2-2 Will the project involve clearing of any trees within 200 feet of the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? A tree is defined by TMC 18.06.845 as any self-supporting woody plant, characterized by one main trunk, with a potential diameter -breast -height of 2 inches or more and potential minimum height of 10 feet. Please mark the appropriate response. ✓ NO - Continue to Question 2-3 YES - Continue to Question 2-3 2-3 Will the project involve clearing of any evergreen trees from within 200 feet of the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? For the purpose of this analysis evergreen means any tree that does not regularly lose all its leaves or needles in the fall. Please mark the appropriate response. ✓ NO - Continue to Question 2-4 YES - Continue to Question 2-4 2-4 Will the project involve clearing within 100 feet of the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? Please mark the appropriate response. NO - Continue to Question 3-0 (Page 2) ✓ YES - Continue to Question 2-5 2-5 Will the project involve clearing within 40 feet of the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? Please mark the appropriate response. NO - Continue to Question 3-0 (Page 2) / YES - Continue to Question 3-0 (Page 2) \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 4 (7' \of Tukwila ESA Screening Checklist Part D: Please review each quesfiwr below for projects that include work b iow the ordinary high water mark of watercourses or the Duwamish/Green or Black Rivers or in wetlands. Review each question carefully, considering all phases of your project including, but not limited to, construction, normal operation, potential emergency operation, and ongoing and scheduled maintenance. Continue to the next question as directed for each No or Yes answer. 3-1 Will the project involve the direct alteration of the channel or bed of a watercourse, the Green/Duwamish rivers, or Black River? For the purpose of this analysis, channel means the area between the ordinary high water mark of both banks of a stream, and bed means the stream bottom substrates, typically within the normal wetted -width of a stream. This includes both temporary and permanent modifications. Please mark the appropriate response. NO - Continue to Question 3-2 YES - Continue to Question 3-2 3-2 Will the project involve any physical alteration to a watercourse or wetland connected to the Green/Duwamish River? For the purpose of this analysis, "connected to the river means" flowing into via a surface connection or culvert, or having other physical characteristics that allow for access by salmonids. This includes impacts to areas such as sloughs, side channels, remnant oxbows, ditches formed from channelized portions of natural watercourses or any area that may provide off channel rearing habitat for juvenile fish from the Duwamish River. This includes both temporary construction alterations and permanent modifications. Watercourses or wetlands draining to the Green/Duwamish River that have a hanging culvert, culvert with a flap gate, diversion, or any entirely man-made or artificial structure that precludes fish access should answer Yes to this question. Please mark the appropriate response. NO - Continue to Question 3-3 YES - Continue to Question 3-3 3-3 Will the project result in the construction of a new structure or hydraulic condition that could be a barrier to salmonid passage within the watercourse or the Green/Duwamish or Black Rivers? For the purpose of this analysis, a barrier means any artificial or human modified structure or hydraulic condition that inhibits the natural upstream or downstream movement of salmonids, including both juveniles and adults. Please mark the appropriate response. NO - Continue to Question 3-4 YES - Continue to Question 3-4 3-4 Will the project involve a temporary or permanent change in the cross -sectional area of a watercourse or the Green/Duwamish or Black Rivers? For the purpose of this analysis, the cross -sectional area is defined as a profile taken from the ordinary high water mark on the right bank to the ordinary high water mark on the left bank. Please mark the appropriate response. NO - Continue to Question 3-5 YES - Continue to Question 3-5 3-5 Will the project require the removal of debris from within the ordinary high water mark of a watercourse or the Green/Duwamish or Black Rivers? For the purpose of this analysis, debris includes, but is not limited to fallen trees, logs, shrubs, rocks, piles, rip -rap, submerged metal, and broken concrete or other building materials. Projects that would require debris removal from a watercourse or the Green/Duwamish or Black Rivers as part of a maintenance activity should answer Yes to this question. Please mark the appropriate response. NO - Continue to Question 3-6 YES - Continue to Question 3-6 \\deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 5 Part D (continued) \ J of Tukwila ESA Screening Checklist 3-6 Will the project result in impacts to watercourses or wetlands that have a surface connection to another watercourse or the Green/Duwamish or Black Rivers but do not contain habitat conditions that support salmonid use? Such areas may include, but not be limited to hillside seeps and wetlands isolated from the watercourse or river that have a surface water connection to the watercourse or river but are not assessable, nor would be assessable to salmonids under natural conditions. Wetlands with a "functions and values" rating for baseflow/groundwater support of 9 and above (or moderate) as described in Cooke (1996) should be included. Please mark the appropriate response. NO - Continue to Question 3-7 YES - Continue to Question 3-7 3-7 Will the project include the construction of artificial waterways or wetlands connected to a watercourse containing salmonids? For the purpose of this analysis, the construction of artificial waterways or wetlands includes wetlands, channels, sloughs, or other habitat feature created to enhance wildlife use, particularly waterfowl use, or may be attractive to wildlife, particularly waterfowl. Please mark the appropriate response. NO - Continue to Question 3-8 YES - Continue to Question 3-8 3-8 Will the project include bank stabilization? For the purpose of this analysis, bank stabilization includes, but is not limited to, rip -rap, rock, log, soil, or vegetated revetments, concrete structures, or similar structures. Please mark the appropriate response. NO - Continue to Question 4-0 (Page 2) YES - Continue to Question 4-0 (Page 2) \\deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 6 / SEPA Checklist STATE ENVIRONMENTAL POLICY ACT CHECKLIST Please respond to all questions. Use separate sheets as necessary. Applicant Responses: A. BACKGROUND 1. Name of proposed project, if applicable: Green River Bank Erosion Repair 2. Name of Applicant: LD Schneider and Associates 3. Date checklist prepared: May 18, 2015 4. Agency requesting checklist: City of Tukwila 5. Proposed timing or schedule (including phasing, if applicable): Construction is schedule to begin August 1, 2015 6. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No 7. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Analysis and Design Report by GeoEngineers 8. 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. Agency Comments \\deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2o11.docx Page 1 SEPA Checklist ,. Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 9. List any government approvals or permits that will be needed for your proposal. Shoreline Substantial Development permit from the City of Tukwila. Hydraulic Project Approval (HPA) from the Washington Department of Fish and Wildlife. 10. 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. The project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and topsoil. The subsurface drainage system consists of a perforated 4-inch schedule 40 PVC pipe that will capture subsurface water along the 165-foot length of the bank repair. 11. 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, the tax lot number, and section, township, and range. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located on the bank of the Green River immediately Southeast of the building located at 14900 Interurban Avenue South. 12. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? Yes \\deptstore\City Common\TeriUQRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 2 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous, other: The project is located on the bank of the Green River b. What is the steepest slope on the site (approximate percent slope)? The river bank is naturally at an approximate 25-30 percent slope. However, the escarpment from the recent bank slough is nearly vertical and approximately 9 feet high. 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. Alluvium consisting of very loose to medium dense silty sand to a depth of approximately 35 feet. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Yes, the bank at this location is subject to drawdown failures. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 3 SEPA Checklist , Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Yes, erosion could result during clearing of the bank. This erosion will be minimized by installing erosion and sediment controls during construction. The site will be permanently stabilized using a robust revegetion plan. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? No new impervios surface is proposed h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Erosion during construction will be minimized by installing erosion and sediment controls. The site will be permanently stabilized using a robust revegetion plan. 2. Air a. What types of emissions to the air would result from the proposal (for example, dust, automobile odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Minor emissions will result from the use of construction equipment and trucking of materials. b. Are there any off -site sources of emissions or odor that may affect your proposal? If so, generally describe. No. \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 4 / f 1 �.' SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments c. Proposed measures to reduce or control emissions or other impacts to air, if any: None. 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. The Green River is located iminediately waterward of the site. The Green River is a Shoreline of the State (Type S). 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. The project will be located wholly within 200 feet of the Ordinary High Water Mark (OHWM) of the Green River. 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. No work will occur waterward of the OHWM. \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 5 i SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 4. Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities, if known. No. 5. Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. Yes. 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. b. Ground: 1. Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. No. Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 6 ' l 1 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 2. Describe waste materials that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following 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: None. 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? Will this water flow into other waters? If so, describe. The project consists of installing a subsurface gravity drainage system to transport water away from the riverbank. The drainage system consists of PVC pipe that will capture subsurface water along the 165-foot length of the bank repair. This groundwater will flow to outfalls located at OHWM of the Green River. We anticipate that this flow will be less than 1 gallon per minute under normal conditions. 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: Surface water runoff from the site is not anticipated. Outfall protection will be installed to minimize the potential fro erosion of the bank. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 7 SEPA Checklist , Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 4. Plants a. Check or circle types of vegetation found on the site: ✓ Deciduous tree: alder, maple, aspen, other — Evergreen tree: fir, cedar, pine, other ✓ Shrubs Grass Pasture Crop or grain Wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other Water plants: water lily, eelgrass, milfoil, other Other types of vegetation b. What kind and amount of vegetation will be removed or altered? Vegetation that will be removed consists of noxious and invasive Himalayan blackberry and English ivy. c. List threatened or endangered species known to be on or near the site. None. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: Noxious and invasive species will be removed from the project area and the bank will be restored with native trees and shrubs. \\deptstore\City Common\Teri \KIRBY - DECEMBER\SEPA Environmental Review Application-Jan0011.docx Page 8 r •. SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 5. Animals a. Circle any birds or animals which have been observed on or near the site or are known to be on or near the site: Birds: e-iawk heron, ag ngbird) other: Mammals: Deer, bear, elk, beaver, other: Fish: Bass, almo ou herring, shellfish, other: Other: b. List any threatened or endangered species known to be on or near the site. The Green River is habitat for endangered Pacific salmon including Chinook salmon, steelhead trout and bull trout. c. Is the site part of a migration route? If so, explain. Yes. The green River is a primary migration route for anadromous salmonids. d. Proposed measures to preserve or enhance wildlife, if any: The project propsed to substantially enhance riparian habitat by removing invasive plants and installing native trees and shrubs. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. None. \\deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 9 SEPA Checklist . • Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 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: None. 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 environmental health hazards, if any: None. \\deptstore\City Common\Teri \KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 10 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: b. Noise 1. What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? The project will not be affected by existing sources of noise. 2. What types and levels of noise would be created by or associated with the project on a short-term or long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. The project will result in short term elevated levels of noise from construction equipment. However, baseline noise levels are high due to traffic on Interurban Avenue South and an existing capital improvement project adjacent to the site. 3. Proposed measures to reduce or control noise impacts, if any: None. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The site is currently used as light commercial office space with associated parking areas. b. Has the site been used for agriculture? If so, describe. Yes, Aerial imagery from King County indicates that the site was farmed in the 1930's. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan201 l.docx Page 11 SEPA Checklist . • Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments c. Describe any structures on the site. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. d. Will any structures be demolished? If so, what? No. e. What is the current zoning classification of the site? Regional Commercial Mixed -Use (RCM). f. What is the current comprehensive plan designation of the site? Regional Commercial Mixed -Use (RCM). g. If applicable, what is the current shoreline master program designation of the site? Urban Conservancy. \\deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 12 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. Yes. The site is wholly within the 100-foot wide river buffer. 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: N/A. 1. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: N/A. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\K1RBY - DECEMBER\SEPA Environmental Review Application-Jan201 I.docx Page 13 SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 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 eliminated? 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? The prosposed trees may obscure the the existing views of the river. \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 14 / f 1 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: c. Proposed measures to reduce or control aesthetic impacts, if any: The proposed planting plan has been developed to maintain existing view corridors to the extent practical. 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? N/A. 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: N/A. SEPA Checklist Agency Comments \\deptstore\City Common \ Teri \KJRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 15 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: 12. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? The owner maintains an existing asphalt pedestrian trial located at the top of the riverbank. A primitive trail is located approximately 200 feet south of the site which is used by anglers to access the river. 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: None. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, National, State, or Local preservation registers known to be on or next to the site? If so, generally describe. None known. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 16 Please respond to all questions. Use separate sheets as necessary. Applicant Responses: b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None known. c. Proposed measures to reduce or control impacts, if any: N/A 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. The site is accessed from Interurban Avenue South via the existing parking area on the south side of the property. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Bus routes are located on Interurban Avenue South. Bus stops are located approximately 500 feet north and south of the site. c. How many parking spaces would the completed project have? How many would the project eliminate? The project proposes no parking and no parking will be eliminated. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 17 SEPA Checklist . Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 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. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. No project will not generate vehicle trips. g. Proposed measures to reduce or control transportation impacts, if any: N/A. 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. \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 18 / \ •\ Please respond to all questions. Use separate sheets as necessary. Applicant Responses: b. Proposed measures to reduce or control direct impacts on public services, if any. N/A. 16. Utilities a. Circle utilities currently available at the site: 4ectnc'tritural g,cigiat; - se serve system other: septic 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. No utilities are proposed for the project. SEPA Checklist Agency Comments \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 19 SEPA Checklist (NON -PROJECT PROPOSALS (E.G., SUBURBAN PLANS AND ZONING CODE TEXT CHANGES) MUST • COMPLETE THE FOLLOWING PAGES). C. SUPPLEMENTAL SHEET FOR NON -PROJECT PROPOSALS (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 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 implemented. Respond briefly and in general terms. Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Agency Comments 1. How would the proposals be likely to increase discharge to water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? Proposed measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants, animals, fish, or marine life? Proposed measures to protect or conserve plants, animals, fish, or marine life are: \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jam2011.docx Page 20 i SEPA Checklist Please respond to all questions. Use separate sheets as necessary. Applicant Responses: Proposed measures to avoid or reduce shoreline and land use impacts are: 6. How would the proposal be likely to increase demands on transportation or public service and utilities? 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. D. SIGNATURE Agency Comments Under the penalty of perjury the above answers under ESA Screening Checklist and State Environmental Policy Act Checklist are true complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decisi Signature: Date Submitted: 20/� \\deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.docx Page 22 CITY OF TUKWILA 71z/ // Department of Community Development SEPA 6300 Southcenter Boulevard, Tukwl,9�: ENVIRONMENTAL Telephone: (206) 431-3670 JUN 242015 REVIEW Community Develo.me APPLICATION FOR STAFF USE ONLY Permits Plus TYPE: P-SEPA Planner: File Number: _ /� V G� 56_?__ Application Complete Date: Project File Number: pt.,/ - (-/ Application Incomplete Date: Other File Numbers: G 1 n6, NAME OF PROJECT/DEVELOPMENT: Green River Bank Repair BRIEF DESCRIPTION OF SCOPE OF WORK: Install a subsurface drainage system and restore an eroded bank on the Green River. LOCATION OF PROJECT/DEVELOPMENT: Give street address or, if vacant, indicate lot(s), block and subdivision, access street, and nearest intersection. 14900 Interurban Avenue South LIST ALL TAX LOT NUMBERS (this information may be found on your tax statement). Parcel #3597000006 0/-7zr.th„ DEVELOPMENT COORDINATOR: The individual who: • has decision making authority on behalf of the owner/applicant in meetings with City staff, • has full responsibility for identifying and satisfying all relevant and sometimes overlapping development standards, and • is the primary contact with the City to whom all notices and reports will be sent. Name: Thomas Bannister- GeoEngineers, Inc. Address: 600 Stewart Street, Suite 1700. Seattle, Washington 98101 Phone: (206) 728-2674 FAX: E-mail: tb fs,er�geoengineers.com Signature: /I'L)i#i 2 Date: 2oic \\Deptstore\City Common \Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.Docx Check items submitted with application Information Requ _ 1. May be waived in unusual cases, upon ?royal of both Public Works and Planning PROJECT DESCRIPTION AND ANALYSIS: 9. Vicinity Map with site location. 10. Provide four (4) copies of any sensitive area studies such as wetland or geotechnical reports if needed per Tukwila's Sensitive Areas Ordinance (TMC 18.45). See the Geotechnical Report Guidelines and Sensitive Area Special Study Guidelines for additional information. 11. Any drawings needed to describe the proposal other than those submitted with the underlying permit. Maximum size 24" x 36". \\Deptstore\City Common\Teri\KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.Docx a 3001-01 DESI 01\00\CAD \21 s 133rd St Sr 3q rh nr 4' 06 FOSTER Sr37th St Y C P e JUN 24 2015 Coma. a1 Development a yryC 5 139th 5t aJ. Y k 5140th St 5 140th 5Cia1,.'� 4 Showalter Middle School es Foster Nigh School 5 144th St St 5 160th St S 146th 5t t a S 150th St eryrer B/Ltf 0 5 1 S61h St S 164th St S 166th St 4 ` f n Crystal Springs • Park ti ya` Sr 6 rhpr °ot, odi ROs Foster Goll links S144th5t 4' S 147th St 1,1 5 150th St 5 152nd 5t d_ 4 s0G 4' LD SCHNIEDER GREEN RIVER BANK REPAIR TUKWILA, WASHINGTON 5 130th 5t S Langston Rd S Langston Rd 5 132nd St S 132nd st 5 133rd St CD P Black River Quarry BLACK RIVER 5143rd St JUNCTION S 143rd PI PROJECT SITE c_ Dent Park '' Fort r49th 5 a W 9 PS rt N S 153rd St f Tukwila Park S Tukwila erglvdf -,; u[hten wy Tukwila Pkwy 3 a o c o z f Southrenter ▪ Mall Baker Blvd as Strander Blvd Frock Dr VICINITY MAP SCALE: 1 "=100' GRAPHIC SCALE 1000 1000 FEET 5 t S 132nd St 13m2n S 134th St S 135th St Black River Ripanan Forest and Wetland 0 t v 1 Tukwila SW 16th St SW 27th sr SHEET INDEX: 1 VICINITY MAP AND SITE MAP 2 NOTES AND SPECIFICATIONS $ SITE PLAN 4 CROSS —SECTIONS 5 DETAILS SCALE: 1 "=400' GRAPHIC SCALE 400 0 400 FEET FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk Rev DESIGNED LJS DRAWN TJM CHECKED JMA DATE 05/27/15 1FILE NO. 21493-001-01 SCALE AS NOTED REVISED. 00/00/00 GEOENGINEERS LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON VICINITY MAP AND SITE MAP SHEET 1 1- 0 z a w z a 1- 3 01\00\CAD\21493001-01 DES GENERAL NOTES: 1. THESE DESIGNS AND DRAWINGS HAVE BEEN PREPARED FOR THE EXCLUSIVE USE OF LD SCNEIDER, AND THEIR AUTHORIZED AGENTS. NO OTHER PARTY CAN RELY ON THE PRODUCT OF OUR SERVICES UNLESS GEOENGINEERS INC. (GEOENGINEERS) AGREES IN WRITING IN ADVANCE OF SUCH USE. 2. THE DRAWINGS CONTAINED WITHIN SHOULD NOT BE APPLIED FOR ANY PURPOSE OR PROJECT EXCEPT THE ONE SPECIFIED. 3. THESE DESIGNS AND DRAWINGS ARE COPYRIGHTED BY GEOENGINEERS, INC. ANY USE, ALTERATION, DELETION, OR EDITING OF THIS DOCUMENT WITHOUT EXPLICIT WRITTEN PERMISSION FROM GEOENGINEERS IS STRICTLY PROHIBITED. ANY OTHER UNAUTHORIZED USE OF THIS DOCUMENT IS PROHIBITED. 4. THE CONTRACTOR SHALL CONSTRUCT THE PROJECT IN ACCORDANCE WITH THE PLANS STAMPED "APPROVED FOR CONSTRUCTION." THESE PLANS WILL BE PROVIDED TO THE CONTRACTOR BY THE ENGINEER OR PROJECT INSPECTOR PRIOR TO CONSTRUCTION. WORK SHALL NOT BE INITIATED WITHOUT THE PLANS APPROVED FOR CONSTRUCTION. 5. THE DESIGNS DEPICTED HEREIN ARE APPROXIMATE AND ARE INTENDED TO EXPRESS THE OVERALL DESIGN INTENT OF THE PROJECT. THESE DESIGNS MAY NEED TO BE ADJUSTED IN THE FIELD DURING CONSTRUCTION IN ORDER TO MEET THE SPECIFIC SITE CONDITIONS AND INTENDED FUNCTION. THESE RIVER IMPROVEMENTS HAVE BEEN DEVELOPED WITH THE UNDERSTANDING THAT A QUALIFIED GEOENGINEERS ENGINEER AND/OR SCIENTIST BE ON -SITE TO PROVIDE CONSTRUCTION GUIDANCE WHILE THE PROJECT IS CONSTRUCTED. 6. CONDITIONS CAN CHANGE AND THESE DESIGNS ARE BASED ON CONDITIONS THAT EXISTED AT THE TIME THE DESIGN WAS PERFORMED. THE RESULTS OF THESE DESIGNS MAY BE AFFECTED BY THE PASSAGE OF TIME, BY MANMADE EVENTS SUCH AS CONSTRUCTION ON OR ADJACENT TO THE SITE, OR BY NATURAL EVENTS SUCH AS FLOODS, EARTHQUAKES, SLOPE INSTABILITY OR GROUNDWATER FLUCTUATIONS. ALWAYS CONTACT GEOENGINEERS BEFORE APPLYING THESE DESIGNS TO DETERMINE IF THEY REMAIN APPLICABLE. 7. THESE PLANS AND ELECTRONIC DRAWINGS ARE BASED ON WASHINGTON STATE PLANE NORTH COORDINATES US FEET AND A NORTH AMERICAN VERTICAL DATUM OF 1988 US FEET. ELEVATIONS AND NORTHINGS AND EASTINGS WITHIN THIS PLANSET ARE BASED ON THESE DATUMS. CONSTRUCTION NOTES: 1. CONTRACTORS WORKING WITHIN THE PROJECT BOUNDARIES ARE RESPONSIBLE FOR COMPLIANCE WITH ALL APPLICABLE SAFETY LAWS. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL BARRICADES, SAFETY DEVICES AND CONTROL OF TRAFFIC WITHIN AND AROUND THE CONSTRUCTION AREA. 2. MATERIAL AND WORKMANSHIP FURNISHED ON OR FOR THE PROJECT MUST MEET THE MINIMUM REQUIREMENTS OF PROJECT PERMITS, APPROVING AGENCIES, SPECIFICATIONS AS SET FORTH HEREIN, OR WHICHEVER IS MORE RESTRICTIVE. 3. THE CONTRACTOR SHALL INSTALL AND MAINTAIN APPROPRIATE SEDIMENT CONTROL DEVICES THROUGHOUT THE WHOLE PROJECT SITE, INCLUDING THE CONSTRUCTION STAGING AREA AND STOCKPILE AREA THROUGHOUT THE PROJECT'S CONSTRUCTION. TEMPORARY CONSTRUCTION AND PERMANENT EROSION CONTROL MEASURES SHALL BE DESIGNED, CONSTRUCTED AND MAINTAINED IN ACCORDANCE WITH APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS. 4. CONSTRUCTION SHALL OCCUR DURING THE APPROVED WDFW FISH WINDOW FOR THE PROJECT AREA. 5. DISCHARGES ENTERING ACTIVE STREAMS ON -SITE SHALL SATISFY ALL STATE AND FEDERAL STANDARDS AND PROJECT PERMIT REQUIREMENTS FOR CONTAMINANTS AND TURBIDITY. SPECIFICATIONS: A. REFERENCED SPECIFICATIONS ARE FROM THE 2014 VERSION OF THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION. MATERIALS: A. RIVERBANK FILL 1. RIVERBANK FILL SHALL CONSIST OF WELL GRADED SAND AND GRAVEL CONFORMING TO EITHER WSDOT STANDARD SPECIFICATION 9-03.10 "AGGREGATE FOR GRAVEL BASE", 9-03.12(2) "GRAVEL BACKFILL FOR WALLS", 9-03.13(1) "GRAVEL BORROW", 9-03.13(2) "SELECT BORROW", OR OTHER MATERIALS AS APPROVED BY THE GEOTECHNICAL ENGINEER. NATIVE ALLUVIUM FROM THE EXISTING RIVERBANK MAY BE INCORPORATED INTO THE RIVERBANK FILL PROVIDED THAT THE ALLUVIUM CONTAINS LESS THAN 30 PERCENT FINES (MATERIAL PASSING THE NO. 200 SIEVE) BY WEIGHT OR AS APPROVED BY THE GEOTECHNICAL ENGINEER. 2. RIVERBANK FILL SHALL BE FREE OF ORGANICS OR OTHER DELETERIOUS MATERIALS. B. DRAINAGE ROCK 1. DRAINAGE ROCK SHALL MEET WSDOT STANDARD SPECIFICATION 9-03.12(2) "GRAVEL BACKFILL FOR WALLS." C. DRAIN PIPE 1. DRAIN PIPE SHALL CONSIST OF 4-INCH SCHEDULE 40 PVC PIPE. THE PIPE SHALL BE SOLID OR PERFORATED AS INDICATED ON THE PROJECT PLANS. THE PIPE AND CONNECTIONS SHALL MEET AASHTO SPECIFICATION M 278. PIPE CONNECTIONS AND DETAILING SHALL BE IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. 2. PERFORATED DRAIN PIPE INSTALLED PARALLEL TO THE SLOPE AND SHALL CONNECT TO SOLID DRAIN D. 1. PIPES (OUTLET DRAINS) THAT DAYLIGHT TO THE SLOPE FACE. SOLID DRAIN PIPES SHALL BE SPACED NO MORE THAN 20 FEET APART. SOLID DRAIN PIPES SHALL DISCHARGE ON AN EROSION PROTECTION PAD OR EXTEND TO THE BASE OF THE EXISTING SLOPE. EROSION PROTECTION PADS SHALL BE CONSTRUCTED OF MATERIAL CONFORMING TO WSDOT STANDARD SPECIFICATION 9-03.9(2) "PERMEABLE BALLAST". THE EROSION PROTECTION PADS SHALL BE FIELD FIT BY THE ENGINEER AT THE DISCHARGE LOCATIONS AND SHALL HAVE A MINIMUM THICKNESS OF 6-INCHES, MINIMUM LENGTH (PARALLEL TO SLOPE) OF 2 FEET, AND MINIMUM WIDTH (PERPENDICULAR TO SLOPE) OF 1 FOOT. NON -WOVEN GEO-TEXTILE NON -WOVEN GEO-TEXTILE SHALL MEET WSDOT STANDARD SPECIFICATION 9-33.1 "GEOSYNTHETIC MATERIAL REQUIREMENTS" FOR NON -WOVEN GEO-TEXTILES USED FOR SEPARATION. E. RECYCLED MATERIAL 1. RECYCLED MATERIAL SHALL NOT BE USED IN AGGREGATES OR FILL. F. TOPSOIL 1. TOPSOIL SHALL CONSIST OF A COMMERCIALLY AVAILABLE 3-WAY MIXTURE CONSISTING OF LOAM SOIL, ORGANICS AND COMPOST PASSING W-INCH SIEVE. G. EROSION CONTROL BLANKET 1.EROSION CONTROL BLANKET SHALL COMPLY WITH WSDOT STANDARD SPECIFICATION 9-14.5(2)D "BIODEGRADABLE EROSION CONTROL BLANKET FOR DITCHES. THE EROSION CONTROL BLANKET SHALL BE 100-PERCENT BIODEGRADABLE INCLUDING THE MESH BACKING. EXECUTION: A. SUBGRADE PREPARATION 1. SUBGRADES SHALL BE CLEARED AND GRUBBED. REMOVE BRUSH, SOD, OR OTHER ORGANIC OR DELETERIOUS MATERIALS PRIOR TO THE PLACEMENT OF FILL. SOFT AREAS SHALL BE OVEREXCAVATED AND REPLACED, AS DIRECTED BY GEOTECHNICAL ENGINEER. 2. SUBGRADE SHALL BE APPROVED BY GEOTECHNICAL ENGINEER. SUBGRADE SOILS SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION BEFORE CONSTRUCTION PROCEEDS. SUBGRADE MATERIALS NOT MEETING GEOTECHNICAL ENGINEER'S APPROVAL SHALL BE REMOVED AND REPLACED WITH RIVERBANK FILL AT DIRECTION OF GEOTECHNICAL ENGINEER. 3. OVEREXCAVATED AREAS SHALL BE REPLACED WITH COMPACTED RIVERBANK FILL MATERIAL. B. SLOPE PREPARATION 1. EXISTING SLOPES SHALL BE RE -GRADED AS REQUIRED TO INSTALL SPECIFIED IMPROVEMENT AND TO MAINTAIN A SAFE WORK ZONE. THE CONTRACTOR IS RESPONSIBLE FOR MAINTAINING A SAFE WORK ZONE AND COMPLYING WITH THE PROVISIONS OF TITLE 296 WASHINGTON ADMINISTRATIVE CODE (WAC), PART N, "EXCAVATION, TRENCHING AND SHORING." 2. FILL PLACED ON OR ADJACENT TO SLOPES SHALL BE PLACED ON HORIZONTAL BENCHES CUT INTO THE EXISTING SLOPE. 3. BENCHES SHALL EXTEND A MINIMUM OF 2-FEET HORIZONTALLY INTO THE SLOPE AND MAY BE CUT IN STAGES AS THE FILL PROGRESSES. C. FILL PLACEMENT AND COMPACTION 1. FILL MATERIAL SHALL BE PLACED IN LOOSE LIFTS NOT EXCEEDING 12-INCHES AND COMPACTED USING EQUIPMENT DESIGNED FOR SOIL COMPACTION. 2. FILL SHALL BE UNIFORMLY COMPACTED TO A MINIMUM 90 PERCENT OF MAXIMUM DRY DENSITY (MDD) AS DETERMINED BY ASTM D-1557. D. SITE REVEGETATION 1. TOPSOIL SHALL BE LOOSELY PLACED ABOVE THE RIVERBANK FILL TO A DEPTH OF 12 INCHES. THE FINISH GRADE SHALL BE TAMPED FIRM AND PROTECTED FROM EROSION. 2. THE EROSION CONTROL BLANKET SHALL BE SHINGLED OR PLACED IN A MANNER SUCH THAT RIVER FLOWS AND WIND DO NOT PEEL UP THE FABRIC. THE EROSION CONTROL FABRIC SHALL BE ANCHORED FOLLOWING THE MANUFACTURER'S INSTRUCTION. 3. NATIVE PLANTS, IDENTIFIED IN THE PLANT SCHEDULE, SHALL BE INSTALLED FOLLOWING THE LAYOUT PROVIDED BY THE GEOENGINEERS BIOLOGIST. PLANTS SHALL BE INSTALLED THROUGH THE EROSION CONTROL FABRIC BY CUTTING THE FABRIC TO THE MINIMUM NECESSARY TO INSTALL THE PLANTS. E. SITE MAINTENANCE AND MONITORING 1. THE SITE WILL BE MAINTAINED BY THE OWNER INTO PERPETUITY AND IN COMPLIANCE WITH THE PROJECT PERMITS. 2. THE SITE WILL BE MONITORED FOR A PERIOD OF FIVE YEARS FOLLOWING PLANT INSTALLATION AS SPECIFIED IN THE DESIGN AND ANALYSIS REPORT BY GEOENGINEERS OR AS REQUIRED BY THE PROJECT PERMITS. ANTICIPATED MATERIAL SCHEDULE APPROXIMATELY 420 YD3 OF CUT AND FILL: • -160 YD3 OF NATIVE MATERIAL TO REMAIN ON SITE. • «160 YD3 OF IMPORTED RIVERBANK FILL. • «96 YD3 OF IMPORTED TOPSOIL. • "'3 YD3 OF 1-INCH DRAIN ROCK. • YD3 OF IMPORTED OUTFALL PROTECTION. FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date Chk Re DESIGNED LJS DRAWN TJM DATE 05/27/15 FILE NO. 21493-001-01 SCALE AS NOTED REVISED: OOJ0DL00 GEOENGINEERS 660 Stewart Steet, SJite 1700 P: 206-728-2674 Seattle, WA 9810' l: 206-728-2132 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON NOTES AND SPECIFICATIONS SHEET 2 CHECKED JMA e/ -0007 G\TAB:PLAN VIEW 01\00\CAD \21495001-01 DES \\` B-i OHWM OHWM ASPHALT TRAIL OHWM 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER \ COMMERCIAL BUILDING OHWM \\ LEGEND BORING LOCATIONS* EXISTING CONTOURS PROPOSED BANK LINES ORDINARY HIGH WATER MARK LIMITS OF WORK SILT FENCE BORING LOGS PROVIDED IN ACCOMPANYING REPORT (GEOENGINEERS 2015) VERTICAL DATUM: NAVD88 OHWM 0 STONE BENCH WM B-1 GREEN RIVER OHWM EL=1 0.0' OHWM OHWM STONE BENCH PLAN VIEW SCALE: 1 "=10' SCALE 10 FEET OUTLET DRAIN (TYP.) BOTTOM OF FILL SLOPE r— SILT FENCE 30" SYCAMORE oHWM 24" SYCAMORE ONWM OHWM TOP OF EXISTING SLOPE 41" SYCAMORE PROTECT TREES PER CITY REQUIREMENTS (TYP) OHW FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote y Chk Rev T DESIGNED LJS —r + + 4- DRAWN TJM CHECKED JMA DATE 05/27/15_. _ -FILE N0. 21493-001-01 SCALE AS NOTED __ REVISED: 00/00/00 GEOENGINEERS BCC Stewart St-eet. Sete '7C2 P: 206 728 2614 Seattle, RA 98'01 F _.^.6-'28-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON SITE PLAN SHEET 3 0 N 1- r g REV a a / 1 4,- \ 24" SYCAMORE (PROTECT TREE PER CITY REQUIREMENT) 30 20 10 �---- PARKING LOT 1 ------------ LANDWARD LIMITS OR WORK 1 EXISTING 1 ASPHALT TRAIL SEE ANCHOR TRENCH DETAIL CUT AS REQUIRED FOR SAFETY AND STABILITY TOP SOIL — EXISTING GRADE 2% RIVERBANK FILL EROSION CONTROL FABRIC SEE DRAIN DETAIL 1 OUTLET DRAIN — SEE ANCHOR TRENCH DETAIL — 30 OUTFALL PROTECTION PER MATERIAL NOTE C-2 — BASE FLOOD ELEVATION SILT FENCE (WATERWARD LIMITS OF WORK) 10 30" SYCAMORE (PROTECT TREE PER CITY REQUIREMENT) 30 — PARKING LOT 20 30 SECTION 40 Distance (Feet) 50 60 A HORIZONTAL SCALE: 1"=5' VERTICAL SCALE: 1"=5' LANDWARD EXISTING ASPHALT TRAIL --------------------------------- 20 — 10 - SEE ANCHOR TRENCH DETAIL LIMITS OR WORK CUT AS REQUIRED FOR SAFETY AND STABILITY SEE DRAIN DETAIL 2.5 1 C-2 EXISTING GRADE TOP SOIL 2% RIVERBANK FILL 70 EROSION CONTROL FABRIC SEE ANCHOR TRENCH DETAIL BASE FLOOD ELEVATION OUTFALL PROTECTION PER MATERIAL NOTE C-2 — 80 85 —30 SILT FENCE (WATERWARD LIMITS OF WORK) OHWM 0 0 20 SCALE SECTION 5 5 FEET 30 40 Distance (Feet) 50 B HORIZONTAL SCALE: 1"=5' VERTICAL SCALE: 1"=5' C-2 60 70 80 0 20 10 0 FOR PERMIT REVIEW - NOT FOR CONSTRUCTION Description Date By Chk Rev DESIGNED LJS DRAWN TJM DATE 05/27/15 FILE NO. 21493-001-01 CHECKED JMA _ _ SCALE AS NOTED REVISED. 00/00/00 •'OSEPij wasti `STO /If�1 • 45765 C GEOENGINEERS 600 Stewart St"eet, SJite 17C0 P: 206-728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON CROSS -SECTIONS AND DRAIN DETAIL SHEET C-3 • Lel CAD\21493001-0I DESI 4" SCH40 PERFORATED PVC DRAIN PIPE EL. 15.0' RIVERBANK FILL NON —WOVEN GEOTEXTILE 12" 12" DRAIN DETAIL SOLID SCH40 PVC OUTLET DRAIN 2% NATIVE SOIL NOT TO SCALE Recommended Planting Schedule Estimated Common Name Scientific Name Size Spacing Quantity 5 Black cottonwood Populus balsamifera 6 - 8 feet in height 10 feet o.c. 9 Western red cedar Thuja plicata 6 - 8 feet in height 10 feet o.c. 5 Big leaf maple Acer macrophyllum 6 - 8 feet in height 10 feet o.c. 5 Pacific dogwood Corpus nutalli 6 - 8 feet in height 10 feet o.c. 25 Vine maple Acer circinatum 6 - 8 feet in height 10 feet o.c. 25 Oceanspray Holodiscus discolor 24-inch in height 5 feet o.c 25 Snowberry Symphoricarpos albus 24-inch in height 5 feet o.c 25 Western serviceberry Amelanchieralnifolia 24-inch in height 5 feet o.c 25 Red osier dogwood Cornus sericea 24-inch in height 5 feet o.c JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATTACH FABRIC TO POSTS. 2"x2" BY 14 Go. WIRE OR EQUIVALENT. IF STANDARD STRENGTH FABRIC USED FILTER FABRIC I 1EIi1-III l� 6' MAX. MINIMUM 4%4'. TRENCH BACKFILL TRENCH WITH NATIVE SOIL OR 3/4"-1.5" POST SPACING MAY BE INCREASED WASHED GRAVEL TO 8' IF WIRE BACKING 15 USED NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBLE J O o �o o 0- CO 2"x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT SILT FENCE DETAIL NOT TO SCALE r r r r r r V v 2X ROOT BALL WIDTH EROSION CONTROL FABRIC LOOSEN AND/OR CUT CIRCLING ROOTS IN ROOT BOUND CONTAINERS BEFORE PLANTING BREAK UP SIDES AND BOTTOMS OF PLANTING PIT TO ALLOW FOR ROOT PENETRATION COMPACT SUBGRADE BELOW ROOT BALL PLANT SCHEDULE TYPICAL PLANTING DETAIL FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk Rev DESIGNED LJS DRAWN DATE 05/27/15 _ FILE N0. 21493=001-01 TJM SCALE AS NOTED CHECKED JMA ,REVISED: 00100 00 GEOENGINEER_ 6C0 Stewart Street, c.iite 17320 F: 236 728 -2674 Seat tie, WA 98101 F 236-728-2232 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON DETAILS SHEET 5 SHORELINE SUBSTANTIAL DEV Parent Project: PL15-0027 MONITORING This File: L15-0032 L.I5-0o32_, GEOENGINEERQ Plaza 600 Building 600 Stewart Street, Suite 1700 Seattle, Washington 98101 206.728.2674 January 17, 2017 LD Schneider and Associates 3200 North Central Avenue, Suite 1470 Phoenix, Arizona 85012 Attention: Kurt Schneider Subject: Restored Conditions Report Green River Bank Repair 14900 Interurban Avenue South Tukwila, Washington GeoEngineers File No. 21493-001-01 INTRODUCTION GeoEngineers, Inc. (GeoEngineers) is pleased to present this assessment of restored conditions following a repair of an eroding bank along the Green River at 14900 Interurban Avenue South in Tukwila, Washington (Figure 1). In the summer of 2016, LD Schneider and Associates (owner) installed a subsurface drainage system to relieve hydraulic pressure within the riverbank following high flows in the river. As described in the GeoEngineers (2016) Design Report for the project, the previous bank failures at the property were, most likely, the result of drawdown failures resulting from excessive hydraulic pressures within the bank. The approved design of the drainage system is include in Attachment A. The project was authorized by the City of Tukwila (City) under Public Works permit PW16-0072 and Shoreline Substantial Development Permit L15-0032; and Hydraulic Project Approval (HPA) 2016-4-245+01 issued by the Washington State Department of Fish and Wildlife (WDFW). 0n behalf of the owner, GeoEngineers completed this assessment as required by the permits issued by the City. The purpose of this report is to document the restoration of the habitat within the shoreline and buffer of the river; and to evaluate the implementation of the site restoration plan that was approved by the City and WDFW. SITE DESCRIPTION AND CONDITIONS The owner's 3.6-acre property (Parcel #3597000006) is located on the left (west) bank of the Green River, approximately 2,000 feet upstream of the confluence with the Black River. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. The parcel is generally flat and the river is not leveed. 0verbank bank flooding is extremely rare, particularly on the left bank of the river because the top of right bank is several feet lower than the top of the left bank. The area LD Schneider and Associates Janus; ...7, 2017 Page 2 of the parcel that is within 200 linear feet of the Ordinary High Water Mark (OHWM) of the Green River is regulated under the City of Tukwila's Shoreline Master Program. The Shoreline designation for the site is Urban Conservancy and the River has a buffer of 100 feet measured landward from OHWM. The site is also designated as a Fish and Wildlife Habitat Conservation Area per Tukwila Municipal Code (TMC) 18.44.090 H. Prior to installation of the subsurface drainage system, the riverbank was vegetated with noxious and invasive species including Himalayan blackberry and English Ivy. Because of the infestation of noxious species and lack of trees, habitat conditions along the riverbank were degraded. GeoEngineers observed evidence of a recent slough of the bank located approximately 100 feet southeast of the commercial building on the property. These type of sloughs occur when high groundwater levels and high river levels saturate the riverbank soil and then the river levels drops or "draws down" faster than the water can drain from the riverbank soil. This creates an imbalance of water pressure. The water pressure pushing the bank from within the soil is no longer balanced by the water pressure from the river and the riverbank is pushed into the river. In our experience, this is the most common riverbank failure mechanism on the lower Green River. The recent sloughing resulted in an approximately 10-foot high near vertical escarpment that damaged the existing asphalt trail at the top of the bank. The trail is separated from the parking lot by a landscaping island consisting of grass and a row of seven mature London Plane trees. PROJECT CONSTRUCTION Installation of the subsurface drainage system began on July 18, 2016. Earthwork and site stabilization was completed on approximately August 15, 2016. The GeoEngineers design engineer was briefly on site on July 28 to observe construction and provide guidance to the contractor. Also, the GeoEngineers biologist was briefly on site on July 22, August 8 and 20, 2016. Prior to earthwork, the contractor removed vegetation from the excavation area, predominantly Himalayan blackberry, and installed a silt fence to prevent erosion into the Green River. A 6-foot tall temporary chain link construction fence was erected to protect the seven London plane trees from damage during construction. The contractor began excavating the bank to install a perforated 4-inch schedule 40 polyvinyl chloride (PVC) pipe to capture subsurface water along the length of the bank repair (Attachment A). During excavation of the bank, an existing rockery was discovered under the English ivy at the northern end of the project. Following guidance from GeoEngineers, the owner elected to leave the existing rockery in place and shortened the overall length of the project. Also, the existing vegetation covering the rockery, consisting of English ivy was left in place. As a result, approximately 90 linear feet of perforated PVC pipe was installed. Three solid 4-inch PVC finger drains were installed to convey the water from the perforated pipe to outfalls located landward of OHWM. Small rock was installed at the outfalls to protect against erosion. Following installation of the drainage system, the excavated area was backfilled with stockpiled excavated material and imported pit run. In accordance with the approved design, the contractor installed an approximately 1-foot thick layer of topsoil above the backfill to achieve the finish design elevations. To minimize erosion, the contractor covered the exposed soils at the site with jute fabric and the silt fence was left in place. The contractor was able to limit the disturbed area to approximately 3,000 square feet. As a result, the number of plants needed to revegetate the riverbank, at the specified density, was reduced. Plant species, GEOENGINEERZ File No. 21493-001-01 LD Schneider and Associates Januk_ _,7, 2017 Page 3 size and quantities were revised based on availability at the time of installation. The table below lists the 104 native plants that were installed at the site, based on information provided by the contractor. In an effort to increase survival, replanting of the bank with native plants was delayed until October 10, 2016. Quantity Common Name Scientific Name Size 11 Western red cedar Thuja plicata 15 gallon 8 Big leaf maple Acer macrophyllum 5 gallon 32 Vine maple Acer circinatum 5 gallon 27 Oceanspray Holodiscus discolor 3 gallon 26 Snowberry Symphoricarpos albus 2 gallon SITE MONITORING AND PERFORMANCE STANDARDS Five years of vegetation monitoring is a requirement of the permits issued by the City. Following the owner's 2016 submittal for a Public Works permit for the project, the City issued a Correction Letter dated May 24, 2016. In the Correction Letter, the City required the owner to submit an agreement stating that the owner will complete the following monitoring and maintenance tasks: 1. Establish a semi -permanent monitoring transect at the site that is at least 100 feet long and runs diagonally through the upper and lower portions of the slope along the river. • 2. Establish the following performance standards for the site: a. The restored areas of the site will achieve 100 percent survival of the installed vegetation along the transect during the first year (2017) following installation of the plants. Installed trees will exhibit positive growth during year one. b. At the end of the 5-year monitoring period (2021) there will be at least 50 percent areal cover of woody species as measured along the transect. c. In all five monitoring years (2017-2021), the site will have less than 10 percent areal cover of undesirable vegetation as measured along the transect. Undesirable vegetation is defined as species that are listed on the King County noxious weeds list. 3. Identify photo point locations and photo document conditions of the site through the 5-year monitoring period. 4. Implement corrective action should the site fail to meet the above performance standards. 5. Provide irrigation to the restored area during the first 3 years of the 5-year monitoring period. Because of the close proximity of the site to the water supply of the building, maintenance crews will adequately water the restored areas of the site with a hose on an as -needed basis. No temporary irrigation system will be installed. 6. Install tree protection fencing around the seven mature London plane trees located at the top of the bank near the site. 7. Submit annual monitoring reports to the City and Karen Walter of the Muckleshoot tribe. GEOENGINEERS� Ftle No 21493-001-01 LD Schneider and Associates Jams., .7, 2017 Page 4 A copy of the Maintenance and Monitoring agreement between the owner and the City is included as Attachment B. In addition to the performance standards of the City, WDFW requires that the site exhibit at least 80-percent survival of the native plants along the transect for a period of three years (2017-2019). Baseline (Year 0) Monitoring On October 21, 2016, a GeoEngineers biologist visited the site to document restored conditions and to collect baseline vegetation monitoring data. Because of recent precipitation, the river was flowing above the elevation of OHWM but not into the restored area of the site. According to the US Geological Survey (2016) streamflow gauge at Tukwila, the water surface elevation of the river was 9.5 feet at the time of our site visit. The biologist observed that the contractor had installed the plants in a manner meeting the intent of restoration plan. The contractor avoided planting big leaf maple and cedar trees under the drip line of the mature London plane trees. As a result, most of the large tree species were installed near the river. The contractor also installed a layer of composted mulch throughout the revegetated area. Straw wattles were installed across the fall line of the riverbank to prevent sediment entrainment and erosion. The biologist established a 100-foot transect along the bank to collect baseline vegetation monitoring data. The southern endpoint of the transect is located at a cedar tree near the trail and extends to the north, paralleling the river (Photo 1). The endpoints of the transect were marked with a wooden stake. Using the line intercept method, the biologist inventoried the number and species of native plants observed within 1 foot of either side of the transect. The table below lists the 11 native plants installed along the transect. BASELINE VEGETATION DATA Areal Transect Location Cover (feet) (feet) Plant Species along Transect Common Name Scientific Name 1 4.7 3.7 Western red cedar Thuja plicata 5 8.9 3.9 Pacific ninebark Physocarpus capitatus 17.3 19 1.7 vine maple Acer circinatum 20.8 23 2.2 vine maple Acer circinatum 26.5 28.2 1.7 vine maple Acer circinatum 31.5 33.2 1.7 Pacific Ninebark Physocarpus capitatus 35.8 37 1.2 Pacific Ninebark Physocarpus capitatus 38.4 41.3 2.9 Pacific Ninebark Physocarpus capitatus 52.3 54.7 2.4 Pacific Ninebark Physocarpus capitatus 57.4 59.2 1.8 Pacific Ninebark Physocarpus capitatus 89.5 91.8 2.3 vine maple Acer circinatum Total Cover 25.5 GEOENGINEERS File No 21493-001-01 1 LD Schneider and Associates lanua, j7, 2017 Page 5 Areal cover of installed native plants along the transect was 25.5 percent. Because of the presence of English Ivy, 4.5-percent of the transect at the north end is covered with this noxious vine. It is our understanding that the restored vegetation on the bank will be maintained by the on -site property management staff as a part of their routine maintenance regimen. Maintenance will include physical removal of noxious and invasive species that may be detrimental to the restored riparian habitat along the riverbank. These noxious and invasive species include but are not limited to: ■ Knotweeds (Polygonum spp.) • Butterfly bush (Buddleja spp.) • Himalayan blackberry (Rubus armeniacus) ■ English ivy (Hedera helix) ■ Scotch broom (Cytisus scoparius) Use of chemical herbicides to control these species is considered unnecessary and is not recommended. Photo 1. Restored conditions along the transect, facing north. We recommend that the installed plants be watered during the dry season for a minimum of three years following plant installation. This watering should occur during the late summer (July to October) and the frequency shall be determined based on weather conditions and plant performance. We anticipate that the site will be watered using a hose from the on -site building. Beneficial volunteer plants, such as other native species, will be encouraged at the site. Installed plants that do not survive will be replaced as required by the authorizations from the City and WDFW. CONCLUSION Based on our observations of the site, it appears that the restoration of the riverbank was completed in general accordance with the approved restoration plan. The project has resulted in the removal of Himalayan blackberry infestation within the disturbed area along the riverbank. The contractor installed native plants in the disturbed areas of the project. GeoEngineers collected baseline monitoring data along a 100-foot long transect using the line intercept method. We found that 11 native plants, with an areal cover of approximately 25.5-percent, were installed along the transect. This baseline data will be used to gauge site performance through the 5-year monitoring period (2017-2021) require by the City and the 3-year monitoring period (2017-2019) required by WDFW. REFERENCES GeoEngineers (2016). Revised Final Analysis and Design Report, dated June 10, 2016. GEOENGINEERS1/7 File No. 21493-001-01 LD Schneider and Associates Jam` ,17, 2017 Page 6 LIMITATIONS We have prepared this revised report for LD Schneider and Associates for the property at 14900 Interurban Avenue South in Tukwila, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the fields of geotechnical engineering, hydrology, and habitat restoration in this area at the time this report was prepared. The conclusions, recommendations and opinions presented in this report are based on our professional knowledge, judgment and experience. No warranty, express or implied, applies to our services and this report. Any electronic form, facsimile or hard copy of the original document (email, text, table and/or figure), if provided, and any attachments should be considered a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Sincerely, Geo a = - rs Inc. T omas A Ban Biologist TAB:JOC:Ieh er, PWS Ilaghan, PWS Asso—late Biologist Attachments: Appendix A. Design Sheets Appendix B. Maintenance and Monitoring Agreement between the City of Tukwila and LD Schneider One copy submitted electronically Disclaimer. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. GEOENGINEERS...0 File No. 21493-001-01 APPENDIX B Maintenance and Monitoring Agreement between the City of Tukwila and LD Schneider GEOENGINEERSQ Plaza 600 Building 600 Stewart Street, Suite 1700 Seattle, Washington 98101 206.728.2674 June 10, 2016 City of Tukwila 6300 Southcenter Blvd. Tukwila, Washington 98188 Attention: Valerie Lonneman, Assistant Planner Subject: Maintenance and Monitoring Agreement LD Schneider Green River Bank Repair 14900 Interurban Avenue Tukwila, Washington File No. 21493-001-01 0n behalf of LD Schneider and Associates (owner), GeoEngineers, Inc. (GeoEngineers) submits this Maintenance and Monitoring letter to the City of Tukwila (City). The purpose of this letter is to serve as the five-year Maintenance and Monitoring agreement between the City and the owner. With this letter, the owner agrees to complete five years of maintenance and monitoring of their Green River Bank Repair Project located at 14900 Interurban Avenue South in Tukwila, Washington. The five years of vegetation monitoring is a requirement of the Shoreline permit issued by the City in 2015. Following the owner's submittal for a Public works permit for the project, the City issued a Correction Letter dated May 24, 2016. In the Correction Letter, the City requires the owner to submit this agreement stating that the owner will complete the following vegetation monitoring and maintenance tasks: 1. Establish a semi -permanent monitoring transect at the site that is at least 100 feet long and runs diagonally through the upper and lower portions of the slope along the river. 2. Establish the following performance standards for the site: a. The restored areas of the site will achieve 100 percent survival of the installed vegetation along the transect during the first year (2017) following installation of the plants. Installed trees will exhibit positive growth during year one. b. At the end of the 5-year monitoring period (2021) there will be at least 50 percent areal cover of woody species as measured along the transect. c. In all five monitoring years (2017-2021), the site will have less than 10 percent areal cover of undesirable vegetation as measured along the transect. Undesirable vegetation is defined as species that are listed on the King County noxious weeds list. City of Tukwila June 10, 2016 \ Page 2 3. Identify photo point locations and photo document conditions of the site through the 5-year monitoring period. 4. Implement corrective action should the site fail to meet the above performance standards. 5. Provide irrigation to the restored area during the first 3 years of the 5-year monitoring period. Because of the close proximity of the site to the water supply of the building, maintenance crews will adequately water the restored areas of the site with a hose on an as -needed basis. No temporary irrigation system will be installed. 6. Install tree protection fencing around the seven mature sycamore trees located at the top of the bank near the site. 7. Submit annual monitoring reports to the City and Karen Walter of the Muckleshoot tribe. The owner commits to completing the above tasks as required by the Shoreline permit for the project. We anticipate that the City will issue their Public Works permit shortly following submittal of this letter and other requested documents. The owner plans to install the proposed drainage system in the summer of 2016 during the allowable work window established by the Washington Department of Fish and Wildlife. Following installation of the drainage system, the river bank will be regraded, per the GeoEngineers design and the site will be stabilized to prevent erosion and water quality impacts. To maximize the success and survival of the installed native plants, the owner will install the plants in the fall or winter of 2016. As such, the owner will monitor the site between 2017 (year 1) and 2021 (year 5). Please call if you have any questions or if we can be of further assistance. Sincerely, GeoEn;. neers, Inc. omas A. Ban iologist 1AB:JOC:Ieh ;,ems ter, PWS One copy submitted in -person Associate Biologist File No. 21493-001-01 GEOENGINEERS 6\TAB:COVER SHEET MODIFIED BY TMICHAUD ON JUN 10, 2016 - 1 P:\21\21493001\00\CAD\21493001-01 FI 'O. FOSTER �r9XCT. 5t ''Tg J 5 140th St 140th St ,n S 146th St f 5 'SOth St SWt 51S6th St 40 5t S t6 5 166thSt 'St 139th St 40 ox 1 r4x N>t' 45. °a y �Rds 000.,Wthrt4 LD SCHNIEDER GREEN RIVER BANK REPAIR TUKWILA, WASHINGTON 5 130tf1 St S anyaSt,a Rd SLan 3 133rd St ae bad liner Quarry BLACK RIVER, JUNCTION PROJECT STTE: " N "49th 5 S 153rd St a 1(*000►ark ►ak `,x jj - 'h y "'�" tea, i 1c SerPhnMet7AY (taker Blvd, s ,41 VICINITY MAP SCALE: 1"=100' GRAPHIC SCALE 1000 1000 FEET H¢a'S rs S 132nd StS- 332n S �3+th S< S 135th 5t O SHEET INDEX: 1 2 3 4 5 SITE MAP SCALE. 1"=400' GRAPHIC SCALE 400 0 400 FEET L1-5 -00$ `Z- GEOENGINEERS LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE SOUTH TUKWILA, WASHINGTON VICINITY MAP AND SITE MAP SHEET 1 J P:\21\21493001\00\CAD\21493001-01 FINAL DESIGN SHEETS.DW6\TAB:NOTES AND DETAILS MODIFIED BY TMICHAUD ON JUN 10, 2016 - 14:52 GENERAL NOTES: 1 THESE DESIGNS AND DRAWINGS HAVE BEEN PREPARED FOR THE EXCLUSIVE USE OF LD SCNEIDER, AND THEIR AUTHORIZED AGENTS. NO OTHER PARTY CAN RELY ON THE PRODUCT OF OUR SERVICES UNLESS GEOENGINEERS INC. (GEOENGINEERS) AGREES IN WRITING IN ADVANCE OF SUCH USE. 2. THE DRAWINGS CONTAINED WITHIN SHOULD NOT BE APPLIED FOR ANY PURPOSE OR PROJECT EXCEPT THE ONE SPECIFIED. 3. THESE DESIGNS AND DRAWINGS ARE COPYRIGHTED BY GEOENGINEERS, INC. ANY USE, ALTERATION, DELETION, OR EDITING OF THIS DOCUMENT WITHOUT EXPLICIT WRITTEN PERMISSION FROM GEOENGINEERS IS STRICTLY PROHIBITED. ANY OTHER UNAUTHORIZED USE OF THIS DOCUMENT IS PROHIBITED. 4. THE CONTRACTOR SHALL CONSTRUCT THE PROJECT IN ACCORDANCE WITH THE PLANS STAMPED "APPROVED FOR CONSTRUCTION." THESE PLANS WILL BE PROVIDED TO THE CONTRACTOR BY THE ENGINEER OR PROJECT INSPECTOR PRIOR TO CONSTRUCTION. WORK SHALL NOT BE INITIATED WITHOUT THE PLANS APPROVED FOR CONSTRUCTION. 5. THE DESIGNS DEPICTED HEREIN ARE APPROXIMATE AND ARE INTENDED TO EXPRESS THE OVERALL DESIGN •INTENT OF THE PROJECT. THESE DESIGNS MAY NEED TO BE ADJUSTED IN THE FIELD DURING CONSTRUCTION IN ORDER TO MEET THE SPECIFIC SITE CONDITIONS AND INTENDED FUNCTION. THES, RIVER IMPROVEMENTS HAVE BEEN DEVELOPED WITH THE UNDERSTANDING THAT A QUALIFIED GEOENGINEERS ENGINEER AND/OR SCIENTIST BE ON -SITE TO PROVIDE CONSTRUCTION GUIDANCE WHILE THE PROJECT IS CONSTRUCTED. 6. CONDITIONS CAN CHANGE AND THESE DESIGNS ARE BASED ON CONDITIONS THAT EXISTED AT THE TIME THE DESIGN WAS PERFORMED. THE RESULTS OF THESE DESIGNS MAY BE AFFECTED BY THE PASSAGE OF TIME, BY MANMADE EVENTS SUCH AS CONSTRUCTION ON OR ADJACENT TO THE SITE, OR BY NATURAL EVENTS SUCH AS FLOODS, EARTHQUAKES, SLOPE INSTABILITY OR GROUNDWATER FLUCTUATIONS. ALWAYS CONTACT GEOENGINEERS BEFORE APPLYING THESE DESIGNS TO DETERMINE IF THEY REMAIN APPLICABLE. 7. THESE PLANS AND ELECTRONIC DRAWINGS ARE BASED ON WASHINGTON STATE PLANE NORTH COORDINATES US FEET AND A NORTH AMERICAN VERTICAL DATUM OF 1988 US FEET. ELEVATIONS AND NORTHINGS AND EASTINCS WITHIN THIS PLANSET ARE BASED ON THESE DATUMS. CONSTRUCTION NOTES: 1. CONTRACTORS WORKING WITHIN THE PROJECT BOUNDARIES ARE RESPONSIBLE FOR COMPLIANCE WITH ALL APPLICABLE SAFETY LAWS. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL BARRICADES, SAFETY DEVICES AND CONTROL OF TRAFFIC WITHIN AND AROUND THE CONSTRUCTION AREA. 2. MATERIAL AND WORKMANSHIP FURNISHED ON OR FOR THE PROJECT MUST MEET THE MINIMUM REQUIREMENTS OF PROJECT PERMITS, APPROVING AGENCIES, SPECIFICATIONS AS SET FORTH HEREIN, OR WHICHEVER IS MORE RESTRICTIVE. 3. THE CONTRACTOR SHALL INSTALL AND MAINTAIN APPROPRIATE SEDIMENT CONTROL DEVICES THROUGHOUT THE WHOLE PROJECT SITE, INCLUDING THE CONSTRUCTION STAGING AREA AND STOCKPILE AREA THROUGHOUT THE PROJECT'S CONSTRUCTION. TEMPORARY CONSTRUCTION AND PERMANENT EROSION CONTROL MEASURES SHALL BE DESIGNED, CONSTRUCTED AND MAINTAINED IN ACCORDANCE WITH APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS. 4. CONSTRUCTION SHALL OCCUR DURING THE APPROVED WDFW FISH WINDOW FOR THE PROJECT AREA. 5. DISCHARGES ENTERING ACTIVE STREAMS ON -SITE SHALL SATISFY ALL STATE AND FEDERAL STANDARDS AND PROJECT PERMIT REQUIREMENTS FOR CONTAMINANTS AND TURBIDITY. SPECIFICATIONS: A. REFERENCED SPECIFICATIONS ARE FROM THE 2014 VERSION OF THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION. MATERIALS: A. RIVERBANK FILL 1. RIVERBANK FILL SHALL CONSIST OF WELL GRADED SAND AND GRAVEL CONFORMING TO EITHER WSDOT STANDARD SPECIFICATION 9-03.10 "AGGREGATE FOR GRAVEL BASE", 9-03.12(2) "GRAVEL BACKFILL FOR WALLS", 9-03.13(1) "GRAVEL BORROW", 9-03.13(2) "SELECT BORROW", OR OTHER MATERIALS AS APPROVED BY THE GEOTECHNICAL ENGINEER. NATIVE ALLUVIUM FROM THE EXISTING RIVERBANK MAY BE INCORPORATED INTO THE RIVERBANK FILL PROVIDED THAT THE ALLUVIUM CONTAINS LESS THAN 30 PERCENT FINES (MATERIAL PASSING THE NO. 200 SIEVE) BY WEIGHT OR AS APPROVED BY THE GEOTECHNICAL ENGINEER. 2. RIVERBANK FILL SHALL BE FREE OF ORGANICS OR OTHER DELETERIOUS MATERIALS. B. 1. DRAINAGE ROCK DRAINAGE ROCK SHALL MEET WSDOT STANDARD SPECIFICATION 9-03.12(4) "GRAVEL BACKFILL FOR DRAINS." C. DRAIN PIPE 1. DRAIN PIPE SHALL CONSIST OF 4-INCH SCHEDULE 40 PVC PIPE. THE PIPE SHALL BE SOLID OR PERFORATED AS INDICATED ON THE PROJECT PLANS. THE PIPE AND CONNECTIONS SHALL MEET AASHTO SPECIFICATION M 278. PIPE CONNECTIONS AND DETAILING SHALL BE IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. 2. PERFORATED DRAIN PIPE INSTALLED PARALLEL TO THE SLOPE AND SHALL CONNECT TO SOLID DRAIN D. PIPES (OUTLET DRAINS) THAT DAYLIGHT TO THE SLOPE FACE. SOLID DRAIN PIPES SHALL BE SPACED NO MORE THAN 20 FEET APART. SOLID DRAIN PIPES SHALL DISCHARGE ON AN EROSION PROTECTION PAD OR EXTEND TO THE BASE OF THE EXISTING SLOPE. EROSION PROTECTION PADS SHALL BE CONSTRUCTED OF MATERIAL CONFORMING TO WSDOT STANDARD SPECIFICATION 9-03.9(2) "PERMEABLE BALLAST". THE EROSION PROTECTION PADS SHALL BE FIELD FIT BY THE ENGINEER AT THE DISCHARGE LOCATIONS AND SHALL HAVE A MINIMUM THICKNESS OF 6-INCHES, MINIMUM LENGTH (PARALLEL TO SLOPE) OF 2 FEET, AND MINIMUM WIDTH (PERPENDICULAR TO SLOPE) OF 1 FOOT. NON -WOVEN GEO-TEXTILE NON -WOVEN GEO-TEXTILE SHALL MEET WSDOT STANDARD SPECIFICATION 9-33.1 "GEOSYNTHETIC MATERIAL REQUIREMENTS" FOR NON -WOVEN GEO-TEXTILES USED FOR SEPARATION. E. RECYCLED MATERIAL 1. RECYCLED MATERIAL SHALL NOT BE USED IN AGGREGATES OR FILL. F. TOPSOIL 1. TOPSOIL SHALL CONSIST OF A COMMERCIALLY AVAILABLE 3-WAY MIXTURE CONSISTING OF LOAM SOIL, ORGANICS AND COMPOST PASSING 1-INCH SIEVE. G. EROSION CONTROL BLANKET AND STRAW WATTLES 1. EROSION CONTROL BLANKET SHALL COMPLY WITH WSDOT STANDARD SPECIFICATION 9-14.5(2)D "BIODEGRADABLE EROSION CONTROL BLANKET FOR DITCHES. THE EROSION CONTROL BLANKET SHALL BE 100-PERCENT BIODEGRADABLE COIR WITHOUT MESH BACKING. THE EROSION CONTROL BLANKET SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. 2. STRAW WATTLE OR SIMILAR SHALL BE 100% BIODEGRADABLE. STRAW WATTLES SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. EXECUTION: A. SUBGRADE PREPARATION 1. SUBGRADES SHALL BE CLEARED AND GRUBBED. REMOVE BRUSH, SOD, OR OTHER ORGANIC OR DELETERIOUS MATERIALS PRIOR TO THE PLACEMENT OF FILL. SOFT AREAS SHALL BE OVEREXCAVATED AND REPLACED, AS DIRECTED BY GEOTECHNICAL ENGINEER. 2. SUBGRADE SHALL BE APPROVED BY GEOTECHNICAL ENGINEER. SUBGRADE SOILS SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION BEFORE CONSTRUCTION PROCEEDS. SUBGRADE MATERIALS NOT 'MEETING GEOTECHNICAL ENGINEER'S APPROVAL SHALL BE REMOVED AND REPLACED WITH RIVERBANK FILL AT DIRECTION OF GEOTECHNICAL ENGINEER. 3. OVEREXCAVATED AREAS SHALL BE REPLACED WITH COMPACTED RIVERBANK FILL MATERIAL. B. SLOPE PREPARATION 1. EXISTING SLOPES SHALL BE RE -GRADED AS REQUIRED TO INSTALL SPECIFIED IMPROVEMENT AND TO MAINTAIN A SAFE WORK ZONE. THE CONTRACTOR IS RESPONSIBLE FOR MAINTAINING A SAFE WORK ZONE AND COMPLYING WITH THE PROVISIONS OF TITLE 296 WASHINGTON ADMINISTRATIVE CODE (WAC), PART N, "EXCAVATION, TRENCHING AND SHORING." 2. FILL PLACED ON OR ADJACENT TO SLOPES SHALL BE PLACED ON HORIZONTAL BENCHES CUT INTO THE EXISTING SLOPE. 3. BENCHES SHALL EXTEND A MINIMUM OF 2-FEET HORIZONTALLY INTO THE SLOPE AND MAY BE CUT IN STAGES AS THE FILL PROGRESSES. C. FILL PLACEMENT AND COMPACTION 1. FILL MATERIAL SHALL BE PLACED IN LOOSE LIFTS NOT EXCEEDING 12-INCHES AND COMPACTED USING EQUIPMENT DESIGNED FOR SOIL COMPACTION. 2. FILL SHALL BE UNIFORMLY COMPACTED TO A MINIMUM 90 PERCENT OF MAXIMUM DRY DENSITY (MDD) AS DETERMINED BY ASTM D-1557. D. SITE REVEGETATION 1. TOPSOIL SHALL BE LOOSELY PLACED ABOVE THE RIVERBANK FILL TO A DEPTH OF 12 INCHES. THE FINISH GRADE SHALL BE TAMPED FIRM AND PROTECTED FROM EROSION. 2. THE EROSION CONTROL BLANKET SHALL BE SHINGLED OR PLACED IN A MANNER SUCH THAT RIVER FLOWS AND WIND DO NOT PEEL UP THE FABRIC. THE EROSION CONTROL FABRIC SHALL BE ANCHORED FOLLOWING THE MANUFACTURER'S INSTRUCTION. 3. NATIVE PLANTS, IDENTIFIED IN THE PLANT SCHEDULE, SHALL BE INSTALLED FOLLOWING THE LAYOUT PROVIDED BY THE GEOENGINEERS BIOLOGIST. PLANTS SHALL BE INSTALLED THROUGH THE EROSION CONTROL FABRIC BY CUTTING THE FABRIC TO THE MINIMUM NECESSARY TO INSTALL THE PLANTS. E. SITE MAINTENANCE AND MONITORING 1. THE SITE WILL BE MAINTAINED BY THE OWNER INTO PERPETUITY AND IN COMPLIANCE WITH THE PROJECT PERMITS. 2. THE SITE WILL BE MONITORED FOR A PERIOD OF FIVE YEARS FOLLOWING PLANT INSTALLATION AS SPECIFIED IN THE DESIGN AND ANALYSIS REPORT BY GEOENGINEERS OR AS REQUIRED BY THE PROJECT PERMITS. ANTICIPATED MATERIAL SCHEDULE APPROXIMATELY 420 YD3 OF CUT AND FILL: • -160 YD3 OF NATIVE MATERIAL TO REMAIN ON SITE. • ' 160 YD3 OF IMPORTED RIVERBANK FILL. • -96 YD3 OF IMPORTED TOPSOIL. • -3 YD3 OF 1-INCH DRAIN ROCK. • -1 YD3 OF IMPORTED OUTFALL PROTECTION. L/S oo3Z GEOENGINEERS. LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE SOUTH TUKWILA, WASHINGTON NOTES AND SPECIFICATIONS SHEET 2 0 PA21\21495001\00\CAD\21495001-01 FINAL DESIGN SNEETB.DWD\TAB:PLAN VIEW MODIFIED Br TMICNAW ON JUr 10, 2016 - 14:52 OHWM -------- ASPHALT --- - -- - 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER COMMERCIAL BUILDING LEGEND STONE BENCH GREEN RIVER OHWM EL=10.0' OHWM / STONE BENCH PLAN VIEW SCALE: 1 "=10' SCALE 10 0 10 FEET k ON OUTLET DRAIN (TYP.) BOTTOM OF FILL SLOPE OHWM x DRAIN • PIPE S SILT FENCE k ASPHA\-T TN 1 �� �' 1RA1L =! TOP OF FILL SLOPE B-2 LIMITS OF WORK PARKING LOT ictvks€4 cow — OHWM TOP OF EXISTING SLOPE oHwM PROTECT TREES PER TREE PROTECTION DETAIL (SEE SHEET 5) L - o3z- GEOENGINEERS_..0 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE SOUTH TUKWILA, WASHINGTON SITE PLAN SHEET 3 0 1 CTIONS MODIFIED BY TMICHAUD ON JUN 10, 2016 - I P:\21\21493001\00\CAD\21493001-01 FINAL DESIGN SNEETS.DW 24" SYCAMORE (PROTECT TREE PER GEOENGINEERS) PARKING LOT 30" SYCAMORE (PROTECT TREE PER GEOENGINEERS) PARKING LOT 1.77,- LANDWARD LIMITS OR WORK 1 EXISTING 1 H- ASPHALT TRAIL N SEE ANCHOR TRENCH DETAIL CUT AS REQUIRED FOR SAFETY AND STABILITY TOP SOIL ,- EXISTING GRADE 2% RIVERBANK FILL NATIVE VEGETATION (TYP.) EROSION CONTROL FABRIC SEE DRAIN DETAIL -J OUTLET DRAIN - SECTION SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) A HORIZONTAL SCALE: 1"=5' VERTICAL SCALE: 1' 5' 1177,- LANDWARD 1 1 SEE ANCHOR TRENCH DETAIL LIMITS OR WORK EXISTING ASPHALT TRAIL CUT AS REQUIRED FOR SAFETY AND STABILITY _/)\. SCALE SECTION 5 5 FEET SEE DRAIN DETAIL 3 OUTFALL PROTECTION PER MATERIAL NOTE C-2 BASE FLOOD ELEVATION SILT FENCE (WATERWARD LIMITS OF WORK) OHWM NATIVE VEGETATION (TYP.) EXISTING GRADE TOP SOIL 2% RIVERBANK FILL EROSION CONTROL FABRIC BASE FLOOD ELEVATION OUTFALL PROTECTION PER • 2.5 MATERIAL NOTE C-2 SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) B HORIZONTAL SCALE: 1"=5' VERTICAL SCALE: 1"=5' 3 SILT FENCE (WATERWARD LIMITS OF WORK) OHWM L l5' - Qa3� GEOENGINEERS t LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE SOUTH TUKWILA, WASHINGTON CROSS -SECTIONS AND DRAIN DETAIL SHEET 4 0 IED BY TmICHAUD ON JUN 10, 2016 - 1 D\TAB:DETAILS moo \21\21493001\00\LAD\21495001-01 Fi RIVERBANK FILL DRAINAGE ROCK PER WSDOT STANDARD SPECIFICATION 9-03.12(4) 4" SCH40 PERFORATED PVC DRAIN PIPE DRAIN DETAIL NON —WOVEN GEOTEXTILE SOLID 5CH40 PVC OUTLET DRAIN NCT TC SCALE MIN. — 1' MIN. TAMPED TAMPED SOIL EROSION CONTROL MAT FASTENER FASTENER — 4' MAX. CENTERS ANCHOR TRENCH SCHEDULE NOT TO SCALE Estimated Quantity 1 1 p • SILT FENCE DETAIL N::T TL' SCALE Recommended Planting Schedule Common Name Scientific Name Site Spacing 12 Black cottonwood Popuius balsamo'era 6 - 8 feet in height 10 feet o.c. 14 Western red cedar Thuja plicate 6 - 8 feet in height 10 feet o c 12 Big leaf maple Acer macrophytum 6 - 8 feet m height 10 feet o.c. 12 Pacific dogwood Cornus nutafi 6 - 8 feet in height 10 feet o.c. 40 Vine ma* Acer circinatum 6 - 8 feat in height 5 feet o.c. 40 0ceanspray Hoiodeecus discolor 24—inch in height 5 feet o c 40 Snowberry Sympnoricarpos albus 24—,nch in freight 5 feet o.c 40 Western sereceberry Ameiancheer alnidoa 24—inch in height 5 feet o c 40 Red war dogwood (.t#rlus sericea 24—nch in height 5 feet o.c v7wv r -0, w L W w yr wW, PLANT SCHEDULE TYPICAL PLANTING DETAIL 1 .NF STRAW WATTLE DETAIL NET T... SCALE 4'-0" PLYWOOD FENCE TO ENCLOSE ENTIRE TREE TREE PROTECTION DETAIL L��S -ad3Z GEOENGINEERS.g LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON DETAILS SHEET 5 to O 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER cowENC1AL BUILDING LEGEND 13.1 4- BORING LOCATIONS* — — —25-- — — EXISTING CONTOURS PROPOSED BANK LINES ONVAJ ORDINARY HIGH WATER MARK LIMITS OF WORK % SILT FENCE OHWM GREEN RIVER EL=10.01 STONE BENCH • 24" SYCAMORE \ ' I PARKING LOT ;.►,ate 10A-rims oh5,,,,,ci .46 N BOTTc Al OF FILL SLOPE r SILT FENCE • BORING LOGS PROVIDED IN ACCOMPANYING REPORT (GEOENGINEERS 2015) VERTICAL DATUM: NAVDBB PLAN VIEW SCALE: 1"=10' 10 SCALE e 10 BERT A PROTECT TREES PER TREE PROTECTION DETAIL (SEE SHEET 5) REV Description Date By Chk Rev DESIGNED LJS DRAWN TJM DATE 06/03/16 FILE NO. 21093-001-01 CHECKED JMA SCALE _5 NOTED REVISED: GEOENGINEERQ 600 Steeort Street, Suite 1700 P: 206-728-2674 Seattle. WA 98101 T: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE SOUTH TUKWILA, WASHINGTON SITE PLAN SHEET 3 L/ 5 - cyd-? Z STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office • 3190 160th Ave SE • Bellevue, WA 98008-5452 • 425-649-7000 711 for Washington Re/ay Service • Persons with a speech disability can call 877-833-6341 August 28, 2015 Kurt Schneider 3200 North Central Ave, Suite 1470 Phoenix, AZ 85012 Re: City of Tukwila Permit L15-0032 - Approved 3200 North Central Ave, Suite 1470 - Applicant Shoreline Substantial Development Permit (SDP) # 2015-NW-2957 Dear Mr. Schneider: On August 27, 2015, the Department of Ecology (Ecology) received notice that the City of Tukwila approved your application for an SDP. Your permit is to install a subsurface drainage system and restore an eroded bank within shoreline jurisdiction of Green River. By law, local governments must review all SDPs for compliance with: • The Shoreline Management Act (Chapter 90.58 RCW); • Ecology's SDP approval criteria (Chapter 173-27-150 WAC); and • The City of Tukwila Local Shoreline Master Program. Local governments, after reviewing SDPs for compliance, are required to submit them to Ecology. Your approved SDP has been received by Ecology. What Happens Next? Before you begin activities authorized by this permit, the law requires you wait at least 21 days from August 27, 2015, the "date of filing." This waiting period allows anyone (including you) who disagrees with any aspect of this permit to appeal the decision to the state Shorelines Hearings Board. You must wait for the conclusion of an appeal before you can begin the activities authorized by this permit. We recommend contacting the Shorelines Hearings Board at (360) 664-9160 before beginning permit activities to ensure that no appeal has been filed. Information on appeals is also posted at http://www.eluho.wa.gov/Decision/Search Cases. Select "Shorelines Hearings Board" from the drop down menu labeled "Board" and enter "Search." The most current appeal will appear on top. If want to appeal this decision, you can find appeal instructions (Chapter 461-08 WAC) at the Shorelines Hearings Board website above. They are also posted on the website of the Washington State Legislature at: http://apps.leg.wa.gov/wac. ® Kurt Schneider August 28, 2015 Page 2 of 2 Other federal, state, and local permits may be required in addition to this shoreline permit. If you have any questions about this letter, please contact David Pater at (425) 649-4253. Sincer avid Pater, Shoreline Specialist Shorelands and Environmental Assistance Program cc: Valerie Lonneman, Tukwila Community Development Thomas Bannister, GeoEngineers, Inc. r\ City of Tukwila Department of Community Development August 24, 2015 NOTICE OF DECISION SHORELINE MANAGEMENT ACT OF 1971 PERMIT FOR SHORELINE SUBSTANTIAL DEVELOPMENT TO: Thomas Bannister, GeoEngineers (Applicant) Kurt Schneider, Owner King County Assessor, Accounting Division Washington State Department of Ecology, NW Regional Office Washington State Attorney General Muckleshoot Indian Tribe Duwamish Indian Tribe Jim Haggerton, Mayor Jack Pace, Director This letter serves as a notice of decision and is issued pursuant to TMC 18.104.170 on the following project and permit approval. I. PROJECT INFORMATION Project File Number: L15-0032; PL15-0027 Applicant: Type of Permit: Project Description: Location: Associated Files: Comprehensive Plan Designation/Zoning District: Thomas Bannister, GeoEngineers Shoreline Substantial Development Permit Install a subsurface drainage system and restore an eroded bank on the west bank of the Green River. The parcel is generally flat and not leveed. The entire project site is within the 200 foot shoreline jurisdiction of the Green River and the work will be performed entirely within the 100 foot river buffer. Work will not occur water ward of the Ordinary High Water Mark (OHWM) as no evidence of toe erosion nor scour have been found on site. 14900 Interurban Ave S, Tukwila, WA 98168 E15-0007 — SEPA Tukwila Urban Center —Transit Oriented Development (TUC-TOD) 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206-431-3670 • Fax 206-431-3665 II. DECISION SEPA Determination: SEPA Determination of Non -Significance was issued on August 17, 2015. Decision on Substantive Permit: The City Community Development Director has determined that the application for a Shoreline Substantial Development Permit does comply with applicable City and state code requirements and has approved that application based on the findings and conclusions contained in the staff report. The Decision on this Permit Application is a Type 2 decision pursuant to Tukwila Municipal Code § 1.8.104.010. Other land use applications related to this project may still be pending. This permit is granted pursuant to the Shoreline Management Act of 1971 and nothing in this permit shall excuse the applicant from compliance with any other Federal, State or local statues, ordinances or regulations applicable to this project, but not inconsistent with the Shoreline Management Act (Chapter 90.58 RCW). This permit may be rescinded pursuant to RCW 90.58.140(8) in the event the permittee fails to comply with the project as approved and any conditions thereof. CONSTRUCTION PURSUANT TO THIS PERMIT MAY NOT BEGIN AND IS NOT AUTHORIZED UNTIL TWENTY-ONE (21) DAYS FROM THE DATE OF RECEIPT WITH THE DEPARTMENT OF ECOLOGY AS DEFINED IN RCW 90.58.140(6) AND WAC 173-14-090, OR UNTIL ALL REVIEW PROCEEDINGS INITIATED WITHIN TWENTY-ONE (21) DAYS FROM THE DATE OF SUCH FILING HAVE TERMINATED; EXCEPT AS PROVIDED IN RCW 90.58.140(5)(a)(b)(c). Construction must begin within 2 years from the effective date of the permit and be substantially completed within 5 years of the effective date of the permit. The effective date of a substantial development permit shall be the date of receipt as provided in RCW 90.58.140(6). III. YOUR APPEAL RIGHTS One administrative appeal to the Shorelines Hearings Board of the Decision is permitted. Any person appealing to the Shorelines Hearings Board may raise certain SEPA issues as part of the appeal to the Shorelines Hearings Board. Appellants should consult the rules and procedures of the Shorelines Hearings Board for details. IV. PROCEDURES AND TIME FOR APPEALING The requirements and procedures for appeals to the Shorelines Hearings Board are set forth in RCW 90.58 and WAC 461.08. Pursuant to RCW 90.58.180 the decision by the City of Tukwila to issue this Shoreline Substantial Development Permit may only be appealed to the Shoreline Hearings Board. Appeals must be filed with the Shoreline Hearings Board within 21-days from the filing of this permit with the Department of Ecology as defined in RCW 90.58.140. For more detailed information on appeals, refer to RCW 90.58 and WAC 461.08. V. INSPECTION OF INFORMATION ON THE APPLICATION Project materials including the application, any staff reports, and other studies related to the Shoreline Substantial Development Permit are available for inspection at the Tukwila Department of Community Development, 6300 VL Page 2 of 3 8/24/2015 W:\Users\Valerie\Notice of Decision\L15-0032 Shoreline NOD Southcenter Blvd., Suite 100, Tukwila, Washington 98188 from Monday through Friday between 8:30 a.m. and 5:00 p.m. The project planner is Valerie Lonneman, who may be contacted at 206-433-7140 for further information. Property owners affected by this decision may request a change in valuation for their property tax purposes. Contact the King County Assessor's Office for further information regarding property tax valuation changes. The notice board must be removed at the expiration of the appeal period unless an appeal is filed. bf Jack Pac . erector Departma4 t of Community Development City of Tukwila VL Page 3 of 3 8/24/2015 W:\Users\Valerie\Notice of Decision\L15-0032 Shoreline NOD i , City of Tukwila Jim Haggerton, Mayor Department of Community Development Jack Pace, Director STAFF REPORT SHORELINE SUBSTANTIAL DEVELOPMENT I. SUMMARY OF PROPOSED ACTION The proposed project is to install a subsurface drainage system and restore an eroded bank on the west bank of the Green River at 14900 Interurban Ave. South. II. GENERAL INFORMATION Project Name: Green River Bank Erosion Repair File Numbers: L15-0032; PL15-0027 Associated Permits: E15-0007 SEPA Applicant: Thomas Bannister, GeoEngineers Location: 14900 Interurban Ave. South (APN#3597000006). Zoning: Regional Commercial Mixed Use (RCM) Comprehensive Plan Designation: RCM SEPA Determination: Determination of Non -Significance issued on August 17, 2015. Attachments: A. Complete Plans (Vicinity Map and Site Map 1, Notes and Specifications 2, Site Plan 3, Cross -Sections and Drain Detail 4, Details 5) B. Revised Analysis and Design Report prepared by GeoEngineers on June 18, 2015 C. Pedestrian Access Easement D. August 17, 2015 SEPA Determination of Nonsignificance 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206-431-3670 • Fax: 206-431-3665 L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 III. PROJECT DESCRIPTION The proposed project is to install a subsurface drainage system and restore an eroded bank on the west bank of the Green River at 14900 Interurban Ave. South. A Shoreline Substantial Development permit is required for the proposed project and SEPA (State Environmental Policy Act) determination of non - significance was issued on August 17, 2015. The entire project site is within the 200 foot shoreline jurisdiction of the Green River and the work will be performed entirely within the 100 foot river buffer (see Site Plan in Attachment A). The project design statement sates that the proposed work will mitigate for ongoing bank sloughing and address potential future drawdown failures, which are believed to be the primary cause of bank sloughing at that location. Work will not occur waterward of the Ordinary High Water Mark (OHWM) as no evidence of toe erosion nor scour have been found on site. A more detailed description of the riverbank drainage provided in the Revised Analysis and Design Report (Attachment B) states "the project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and native soil." The following aerial photo illustrates the location of the project parcel, which includes an approximately 57,000 square foot, two-story office building and adjacent parking areas. The parcel is generally flat and not leveed. Figure 1 — Project Site VL Page 2 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR / l 1 L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 IV. TUKWILA SHORELINE MASTER PROGRAM — BACKGROUND The City of Tukwila adopted a new Shoreline Master Program (SMP) on August 15, 2011.which was approved by the Washington State Department of Ecology on October 14, 2011 and became effective October 28, 2011. This project is subject to the new Shoreline Master Program. A. Shoreline Environment Designation The shoreline environment designation for the site is Urban Conservancy; the purpose of the Urban Conservancy Environment is to protect ecological functions where they exist in urban and developed settings, and restore ecological functions where they have been previously degraded, while allowing a variety of compatible uses. The shoreline buffer in the Urban Conservancy environment is 100 feet from the ordinary high water mark, when the river bank is not fortified with a levee. All proposed work will fall within the 100' shoreline buffer. Shoreline restoration projects are a permitted use within the shoreline buffer in the Urban Conservancy Environment. Figure 2 depicts the Shoreline Environmental Designation for this reach of the Duwamish River. .�-+.Ordinary Hipp Water Mark ( -.. ] Aquatic Environment - High Intensity -100' Buller High pm Intensity - Outside Butter — Type 3 Stream (80' Buffer) L!» o UrbanConservancy - Levee -125' Buffer ® Type 3 Stream in Pipe no Urban Conservancy - Levee - Outside Buffet — Type 4 Stream (50' Buffer) Urban Conservancy - No levee -100' Buffer Type 4 Stream In Pipe Urban Conservancy - No Levee - Outside Buffer 17771 Fish and WIl41fe Habitat Areas (100' Buffer) Shoreline Residential - Min. 50' Buffer Potential Wetlands SBorekne Residential - Outside Buffer - Category II Wetland (100' Butter) Tukwila City Limits t Category Ig Wetland (80' Buffer' saltPotental Annexation Area Category IV Wetland (50' Buffer) Figure 2 — Shoreline Environment Designation map Type 2 Stream (100' Buffer) ro Type 2 Stream in Pipe e 1 d00' leafing 0H/q vegan mina locations tiff apprortaate oily. Witenarxs slain re gas napkin no Cenisaneye4. 21 VL Page 3 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR i L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 B. Shoreline Goals and Policies: The following section discusses the Shoreline Master Program (SMP) goals and policies that apply to this project and are excerpted from Chapter 6 of the City's SMP. 6.6 Access and Recreational Use, Comprehensive Plan Goal 5.6 Goal: Increase the amount and diversity of opportunities for public recreation and access to and along the river, including visual and cultural access, access to the water's edge, opportunities for small boat navigation and access, and connections to other neighborhoods, consistent with the shoreline character. • Policy 5.6.3: Incorporate river access requirements to guide the design, location and management of shoreline public access in short plats over 4 lots and all subdivisions as well as multi -family, commercial and industrial development; to identify types of access appropriate and feasible for various site conditions and locations; and to establish strategies, funding sources and priorities for acquisition and enhancement of shoreline public access. • Policy 5.6.5: Where shoreline development provides public access areas, reserve such areas for use by the public through the means most appropriate for the type, scale and impacts of the development, such as dedication, donation or sale of an easement or right-of-way to the City. Staff Response: There is an existing perpetual, non-exclusive easement for public access on the site, which is currently paved as a recreational trail. (See Attachment C). 6.7 Transportation within the Shoreline Jurisdiction, Comprehensive Plan Goal 5.7 Goal: Safe corridors and amenities for pedestrians, cyclists and users of public transportation, allowing more citizens to access and enjoy the river. • Policy 5.7.2: Ensure the transportation uses within the shoreline jurisdiction and within those corridors identified as river cross -connections provide safe, convenient and attractive pedestrian, bicycle and boater access and facilities for public transportation. • Policy 5.7.3: Minimize transportation impacts to the natural environment (such as air, noise, odor or water pollution) and enhance the natural environment wherever possible through planting trees and other habitat features. Staff Response: The proposed restoration work will stabilize the river embankment, enhancing the stability of the public trail that provides riverside views„ The project will enhance the natural environment through mitigation plantings, which will minimize the transportation impacts to the adjacent riparian environment. VL Page 4 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR f f \ L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 6.9 Natural Environment and Habitat Use, Comprehensive Plan Goal 5.9 Goal: Restored, enhanced, and protected natural environment resources along the river, including trees, wildlife habitat and features with value for long-term public, scientific, and educational uses. • Policy 5.9.1: Ensure that shoreline development results in no net loss of shoreline ecological function, minimizes impacts on wildlife and that significant vegetation, sandbars, wetlands, watercourses, and other critical areas identified as important for habitat are maintained through the proper location, design, construction, and management of all shoreline uses and activities. • Policy 5.9.2: Ensure that shoreline development and activities protect riverbank vegetation and, where feasible, restore degraded riverbanks in accordance with the vegetation management provisions of the Shoreline Master Program, in order to minimize and compensate for impacts to fish and wildlife habitat. Staff Response: The proposed work will improve the shoreline ecological function by stabilizing the river bank and thereby reducing potential erosion and sediment release into the river which can impact water quality. Work will remove invasive species and densely revegetate the area with native shrubs and trees, which will ultimately provide additional shade and organic input into the system. All work will be in conformance with the regulations of the Shoreline Master Program and result in no net loss of shoreline ecological functions. 6.10 Water Quality, Surface Water and Flood Control Use, Comprehensive Plan Goal 5.10 Goal: Improved water quality and quantity control programs affecting the Green/Duwamish River that improve the river's water quality, provide habitat for fish. • Policy 5.10.1: Design, locate, and manage shoreline development including streets, flood control projects, surface water drainage and sewer systems, clearing and grading activities, and landscaping in a manner which minimizes opportunities for pollutants to enter the river, provides erosion control and otherwise protects water quality. Staff Response: The proposed work involves the installation of a subsurface drainage system to transport water away from the failure plane. The proposed work will reduce the potential for further erosion, which adversely affects water quality. Best management practices for sediment and erosion control will be applied in order to mitigate for any temporary impacts on water quality during earth - moving activities. 6.11 Public Health, Safety and Welfare, Comprehensive Plan Goal 5.11 Goal: Shoreline uses that do not endanger public health, safety and welfare, or the capacity of the river to provide long-term benefits and resources to the community. VL Page 5 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 • Policy 5.11.1: Design, locate, and manage shoreline uses, such as capital improvement projects and private development, in a manner that does not endanger public health, safety and welfare, and enhances the capacity of the river to provide long-term flood protection, habitat and other benefits and resources to the community and the environment. Staff Response: The project is within an area where Muckleshoot tribal members exercise their treaty fishing rights. Currently there is no access to the river within the project site. However, the project site is located approximately 150 feet north of an existing trail that is used by tribal member to access the river for fishing. This trail will remain open during construction, parking will be available, and access to the river via the trail will be unimpeded. It is anticipated that the restoration work may create better access conditions and as a result more tribal members may set nets and fish in this area once the project is complete. 6.12 Shoreline Use Preferences, New Comprehensive Plan Goal 5.12 Goal: Tukwila, in developing and implementing its shoreline master program for shorelines of statewide significance, including the Green/Duwamish River, shall give preference to uses in the following order of preference which: 1. Recognize and protect the statewide interest over local interest; 2. Preserve the natural character of the shoreline; 3. Result in long term over short term benefit; 4. Protect the resources and ecology of the shorelines; 5. Increase public access to publicly owned areas of the shorelines; 6. Increase recreational opportunities for the public in the shoreline; 7. Provide for any other element as defined in RCW 90.58.100 deemed appropriate or necessary. Staff Response: The proposed work will provide many of the benefits listed, including long term environmental, social, aesthetic, and safety benefits. V. SHORELINE REGULATIONS TMC 18.44.130 B. 3. Shoreline Administration states that a substantial development permit shall be granted only when the development proposed is consistent with the shoreline master program (SMP). The relevant SMP policies were discussed above. Below is a discussion of the relevant shoreline master program regulations that are incorporated into the zoning code that apply to this permit application. 1. TMC 18.44.050 Permitted Uses TMC 18.44.050 identifies permitted uses in the Urban Conservancy environment. The proposed project is a permitted use under TMC 18.44.050 B.1.a.: "Shoreline restoration projects". VL Page 6 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR \ L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 2. TMC 18.44.070 Development Standards TMC 18.44.070 C. establishes development standards for the Urban Conservancy Environment. These include setbacks, site configuration, height restrictions, and lighting standards. As this project does not involve the construction of structures, setbacks, site configuration, and height restrictions do not apply. TMC 18.44.070.D Surface Water and Water Quality TMC 18.44.070 D. provides development standards for surface water and water quality related to shoreline development. The proposed project will not generate any increase in surface runoff. The project involves the installation of a subsurface drainage system to transport water away from the failure plane, which can be expected to improve water quality by decreasing the likelihood of erosion, thereby improving water quality at the site. Projects are required to be designed so as to cause no net loss to shoreline ecological functions. No net loss has been addressed above under the discussion of the consistency of this project with shoreline goals and policies. 18.44.070.E Flood Hazard Reduction TMC 18.44.070 E. sets standards for structural flood hazard reduction structures. Not applicable. TMC 18.44.070. F Shoreline Stabilization TMC 18.44.070 F. provides regulations for work intended to minimize or prevent failure of riverbanks resulting from waves, tidal fluctuations, or river currents. The Revised Analysis and Design Report (Attachment B) supports the use of bioengineering techniques to protect the site from additional sloughing. The project will avoid all direct impacts to the ecological processes of the shoreline. Any indirect impacts due to the earth moving and invasive plant removal in the shoreline buffer will be mitigated through appropriate sediment and erosion control BMPs. TMC18.44.070.G Archaeological, Cultural, and Historical Resources TMC 18.44.070 G. states regulations regarding coordination with affected tribes and procedures for the discovery of archaeological resources. Applicant will comply with all local, state, and federal laws in the event that archaeological or paleontological artifacts are encountered. Notice of Application was sent to the Muckleshoot and Duwamish Tribes. VL Page 7 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 TMC 19.44.070.H Environmental Impact Mitiigation TMC 19.44.070 H. addresses the mitigation of unavoidable impacts on the shoreline to ensure the "no net loss" standard is met. The project will result in approximately 5,000 square feet of temporary impacts to the shoreline. These impacts are necessary to eliminate the inherent public safety issue posed by the slope failure and to maintain safe, public access to the shoreline on the property. To rectify these unavoidable impacts, the project follows the mitigation sequencing steps identified in TMC 18.44.070 H(3). By following this protocoll the project will result in no net loss of shoreline ecological function. TMC 19.44.070.I Off Street Parking and Loading Requirements Not applicable. TMC 19.44.070.J Land Altering Activities TMC 18.44.070.J, Development Standards (Section 9.11 of the SMP) addresses clearing, grading and landfill activities in the shoreline jurisdiction. The SMP requires all land altering activities in the shoreline jurisdiction to be in conjunction with an underlying land development permit, except for shoreline restoration projects. In addition, all activities shall meet the following standards: 1. Land altering shall be permitted only where it meets the following criteria: a. The work is the minimum necessary to accomplish an allowed shoreline use; Response: Fill will be placed to approximate the pre -slough slope angle, or 2.5:1 slope. No work will occur waterward of the OHWM so as to minimize impacts to the aquatic habitat at the site. b. Impacts to the natural environment are minimized and mitigated; Response: The slope angle of the bank reconstruction will be established to fit within the site constraints, including avoiding damage to the large sycamore trees atop the bank, limiting disturbance to the root zone and transitioning into the native banks adjacent to the repair. Tree protections will be established at the maximum practical distance from the trunks of the seven mature sycamore trees along the top of the bank. The site is currently infested with Himalayan blackberry, which will be removed and revegetated with native species to help stabilize the bank. c. Water quality, river flows and/or fish habitat are not adversely affected; Response: Temporary erosion and sediment controls will be installed prior to site work. A silt fence will be installed on the downslope construction limits, near the OHWM, as the primary water quality protection. Contingency water quality protections VL Page 8 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15.0032 SR L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 include additional silt fence, silt curtains, and straw wattles. Additional erosion protection will be provided due to the potential for high flow events in the river by including a biodegradable erosion control fabric, which will provide additional stabilization to the bank during heavy rain events. d. Public access and river navigation are not diminished; Response: There is an existing perpetual, non-exclusive easement for public access on the site, which is currently paved as a recreational trail. The escarpment damaged this portion of the trail, which is now closed due to safety concerns. To accommodate the proposed slope re -grading angle of 2.5:1 the trail may have to be realigned following bank restoration. e. The project complies with all federal and state requirements and the project has been coordinated with the U.S. Army Corps of Engineers; Response: The project has been designed to comply with all federal and state requirements. f. The project complies with the vegetation protection criteria of the Vegetation Protection and Landscaping Section; Response: The proposed project is compliant with the regulations for vegetation protection and landscaping. See `Vegetation Protection and Landscaping' section, below. g. Documentation is provided to demonstrate that the fill comes from a clean source. Response: The Revised Analysis and Design Report (Attachment B) states that approximately 160 cubic yards of clean riverbank fill will be imported to supplement the approximate 160 cubic yards of native material that will be incorporated back into the riverbank. It should be noted that the discussion on fill during development of the City's SMP was focused on fill placed waterward of the ordinary high water mark, which this project does not propose. 2. Clearing, grading and landfill activities, where allowed, shall include erosion control mechanisms, and any reasonable restriction on equipment, methods or timing necessary to minimize the introduction of suspended solids or leaching of contaminants into the river, or the disturbance of wildlife or fish habitats in accordance with the standards in the Grading Chapter, TMC 16.54. Response: Best Management Practices, such as silt fence, silt curtains, and straw wattles, will be installed before any earthmoving activities take place and will be maintained throughout construction in order to prevent sediment from entering the Green River. TMC 19.44.070.K Marinas, Boat Yards, Dry Docks, Boat Launches, Piers, Docks, and Over -water Structures VL Page 9 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 Not applicable. TMC 19.44.070.L Signs in the Shoreline Jurisdiction Not applicable. 3. TMC 18.44.080 Vegetation Protection and Landscaping TMC 18.44.080 provides requirements for landscaping in both the buffer and non -buffer areas of the shoreline environment. Invasive vegetation shall be removed as part of site preparation and maintenance will include physical removal of noxious and invasive species that may be detrimental to the restored riparian habitat along the riverbank. Seven large Sycamore trees along the top slope of the bank shall be retained and protected during construction. The contractor shall establish tree protections at the maximum practical distance from the trunks of the Sycamore trees and a GeoEngineers biologist will be on site to observe grading activities in the vicinity of the trees. The applicant has provided a landscaping schedule for the project area, which is comprised entirely of native plants. Plant size and spacing is in accordance with the regulations for the shoreline jurisdiction. The landscaping plan also complies with the provisions for areas in the river buffer, as the entire site is within the buffer. Plants will be installed in such a way to promote shade and overhanging vegetation near the OHWM. The landscaping plan accounts for seasonal fluctuation in river levels and variable hydrology up the riverbank slope. GeoEngineers has recommended that landscaping be watered during the dry season for a minimum of three years following installation either by hose or with a temporary irrigation system. Per TMC 18.44.080.C.1.1. and m. applicant shall ensure the following requirements are met: 1) Site preparation and planting of vegetation shall be in accordance with best management practices for ensuring the vegetation's long-term health and survival. 2) Native vegetation in the shoreline installed in accordance with the preceding standards shall be maintained by the property owner to promote healthy growth and prevent establishment of invasive species. Invasive plants (such as blackberry, ivy, knotweed, bindweed) shall be removed on a regular basis, according to the approved maintenance plan. To ensure these standards are met, applicant shall submit a five year maintenance and monitoring plan prior to construction. The maintenance plan shall cover the following areas: a) Establishment of a permanent transect that is at least 100ft long that covers both the upper and lower ranges of the slope (runs diagonally). Photo points of the site shall be included in annual reports. b) Success standards for the mitigation site shall include a 100% survival rate after the first year, and positive growth of tree cover with at least 50% woody plant cover by year 5. The site shall also be monitored to ensure less than 10% weed cover in all years. If monitoring should suggest plantings are not meeting standards, appropriate contingency measures will be implemented such as replanting and/or weed control. VL Page 10 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR r. �\ L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 c) Provision of irrigation for the first three growing seasons during the dry months (June — October) as needed. d) Annual monitoring reports to be submitted to the city by December 31 of each year for the five years following installation. 4. 18.44.100 Public Access TMC 18.44.100 addresses public access requirement for the SMP. Public access is required when a development or use would create additional demand for public access through the addition of square footage to an existing building or the intensification in land use through the conversion of a warehouse to a retail or office use. This development standard does not apply to this project. There is an existing public trail which has been closed in this area due to safety concerns after a portion of the trail was undercut by the sloughing bank.(Attachment C). 5. TMC 18.44.110 Shoreline Design Guidelines This section of the TMC does not apply as no structures are being constructed. VI. COMMENTS Notice was sent to property owners and tenants within 500' of the site and agencies with jurisdiction. No comments were received from the general public regarding the proposed work. Comments were received from the Muckleshoot Indian Tribe, stating that the project site is an area where Muckleshoot tribal members exercise their treaty fishing rights and that therefore the contractor must ensure that Tribe members will continue to have access to the Green River during construction. Comments also noted that an increase in fishing in that area is a likely outcome of the project work, as the project may create better river access. The Muckleshoot Tribe also requested to be sent the as -built drawings and any monitoring reports generated by the project for their files. These comments were forwarded to the applicant, who replied by stating that the area of proposed work does not currently provide access to the river, but is located 150' north of the trail that is used by tribal members for fishing. They confirmed that the work will not impede access to this area. As -built plans shall be provided to the tribe upon project completion. VII. SEPA A SEPA Determination of Nonsignificance was issued on August 17, 2015. A copy of the SEPA determination letter is provided as Attachment D. VL Page 11 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 CONCLUSIONS 1. The proposed project is located on the west bank of the Green River at 14900 Interurban Ave. South. The entire project site is within the 200 foot shoreline jurisdiction of the Green River. 2. The shoreline environment designation for the project area is Urban Conservancy, with a buffer width of 100 feet. The work will be performed entirely within the river buffer. 3. Shoreline restoration is a use permitted by the Urban Conservancy shoreline environment designation. 4. The proposed project is to install a subsurface drainage system and restore an eroded bank, which geotechnical analysis shows to be sloughing due to a drawdown failure. 5. The proposed project is consistent with the Access and Recreational Use, Natural Environment and Habitat Use, Water Quality, Surface Water and Flood Control Use, Public Health, Safety and Welfare, and Shoreline Use Preferences goals and policies of the SMP. 6. The project has analyzed the no net loss provisions of the SMP and will avoid all direct impacts to the ecological processes of the shoreline. Any indirect impacts due to the earth moving and invasive plant removal in the shoreline buffer will be mitigated to cause no net loss through sediment and erosion control BMPs. 7. There are currently seven mature Sycamore trees along the top of the bank. The root systems that support these trees will be protected during construction to the maximum extent practicable due to the proximity of the trees to the project site. In the event of damage/death to the existing trees, contingency mitigation measures will be applied. 8. In the application materials, the applicant has stated the mitigation plantings will be monitored annually by a qualified biologist for the first 5 years. Success standards for the mitigation site will include a 100% survival rate after the first year and an 80% survival rate annually thereafter for 5 years. 9. TMC 18.44.080.C.1.1 requires the use of Best Management Practices for soil preparation, planting, and site maintenance to ensure the vegetation's long-term health and survival. In order to demonstrate these requirements will be met, the applicant shall submit a 5-year maintenance and monitoring plan, which shall be approved by the City's Urban Environmentalist. 10. The proposed project is consistent with the applicable development standards of the SMP: a) Surface Water and Water Quality: the project will follow the 2009 King County Surface Water Design Manual. b) Shoreline Stabilization: Bioengineering techniques are recommended to protect the site from additional sloughing. The project will avoid all direct impacts to the ecological processes of the shoreline. Any indirect impacts due to the earth moving and invasive plant removal in the shoreline buffer will be mitigated through appropriate sediment and erosion control BMPs. c) Archaeological, Cultural, and Historical Resources: Applicant will comply with all local, state, and federal laws in the event that archaeological or paleontological artifacts are encountered. d) Environmental Impact Mitigation: The project will result in approximately 5,000 square feet of temporary impacts to the shoreline. To rectify these unavoidable impacts, the project will follow the mitigation sequencing steps identified in TMC 18.44.070 H(3). e) Land Altering Activities: The work is the minimum needed to accomplish an allowed shoreline use; the impacts have been minimized and mitigated; water quality, river flows and VL Page 12 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR l L15-0032-Green River Bank Erosion Repair Shoreline Substantial Development August 24, 2015 fish habitat shall not be adversely affected; public access and river navigation are not affected; the project has been designed to comply with all state and federal requirements; the fill complies with the vegetation protection criteria of the SMP; the fill source has not been determined; and best management practices will be utilized during the earth moving work. 11. Comments were received from the Muckleshoot Indian Tribe and have been addressed. As - built plans shall be sent to the tribe upon completion of the project. 12. A SEPA Determination of Nonsignificance was issued on August 17, 2015. VIII. RECOMMENDATION Approve the shoreline substantial development permit with the following conditions: 1. Prior to construction, submit a five year maintenance and monitoring plan covering the following areas: a) Establishment of a permanent transect that is at least 100ft long that covers both the upper and lower ranges of the slope (runs diagonally). Photo points of the site shall be included in annual reports. b) Success standards for the mitigation site shall include a 100% survival rate after the first year, and positive growth of tree cover with at least 50% woody plant cover by year 5. The site shall also be monitored to ensure less than 10% weed cover in all years. If monitoring should suggest plantings are not meeting standards, appropriate contingency measures will be implemented such as replanting and/or weed control. c) Provision of irrigation for the first three growing seasons during the dry months (June — October) as needed. d) Annual monitoring reports to be submitted to the city by December 31 of each year for the five years following installation. VL Page 13 of 13 08/24/2015 W:\Users\Valerie\Shoreline\L15-0032 SR at* al J uP'.ui&a , Department Of Community Development AFFIDAVIT OF DISTRIBUTION I, Valerie Lonneman, HEREBY DECLARE THAT: Notice of Application X Notice of Decision Notice of Public Hearing Notice of Public Meeting Determination of Non- Significance Mitigated Determination of Non - Significance Determination of Significance & Scoping Notice Short Subdivision Agenda Notice of Application for Shoreline Mgmt Permit Shoreline Mgmt Permit Board of Appeals Agenda Packet Board of Adjustment Agenda Packet Official Notice Notice of Action Was mailed to each of the addresses listed/attached on this 24 day of August, 2015 Project Name: Green River Bank Erosion Repair Project Number: L15-0032 (Shoreline) Associated File Number (s): E15-0007 (SEPA) Mailing requested by: Valerie Lonneman Mailer's signature: /� W:\USERS\VALERIE\AFFIDAVIT OF DISTRIBUTION.DOC laura.murphy@muckleshoot.nsn.us, Muckleshoot Tribe Karen.Walter@rnuckleshoot.nsn.us, Muckleshoot Tribe mike.middleton@muckleshoot.nsn.us, Muckleshoot Tribe james@duwamishcleanup.org, Duwamish Tribe Christie.Most@kingcounty.gov, King County Assessor's Office Larry.Fisher@diw.wa.gov, WA Dept. of Fish and Wildlife tbannister@geoengineers.com, Thomas Bannister, Applicant W:\USERS\VALERIE\AFFIDAVIT OF DISTRIBUTION.DOC GEOENGINEERS _,0 Letter of Transmittal Plaza 600 Building, 600 Stewart Street, Suite 1700, Seattle, Washington 98101, Telephone: 206.728.2674, Fax 206.728.2732 www.geoengineers.com To: Valerie Lonneman City of Tukwila Department of Community Development 6300 Southcenter Boulevard Tukwila, Washington 98188 Regarding: Green River Bank Erosion Repair We are sending: ® Attached Date: August 6, 2015 File: 21493-001-01 ❑ Under Separate Cover Copies Date Description 2 7/14/15 Correction Letter # 1 2 8/6/15 Revision Submittal Form 2 7/30/15 Memorandum in response to Correction Letter #1 2 7/30/15 SEPA Application 2 7/30/15 Revised Analysis and Design Report These are transmitted as checked below: ❑ For Your Use As Requested ❑ Returned 0 For Review and Comment ❑ Other (see remarks) We are sending via: 0 US Mail ❑ Overnight ® Courier Remarks: Copy To: ram+ AUG 062015 cornrnutty Development Signed: T omas Bann' -r tbannister@geoengineers.co DISCLAIMER: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. d any attachments are only a copy of the City () Tukwila REVISION SUBMITTAL Department of Community Development PLANNING DIVISION 6300 Southcenter Boulevard, Suite #100 Tukwila, Washington 98188 Phone: 206-431-3670 AUG 062615 CoTmunity Dev6opment Revision submittals must be submitted in person at the Permit Center, ACCOMPANIED BY RESPONSE DOCUMENTS AND THIS COMPLETED FORM. Revisions will not be accepted through the mail, email, fax, etc. Date: 8/6/2015 Permit Number: L15-0032 & E15-0007 Project Name: Green River Bank Erosion Repair Project Address: 14900 Interurban Ave S. Project Contact: Thomas Bannister Contact Phone number: (206) 728-2674 City Planner: Valerie Lonneman PLEASE ATTACH A COPY OF ANY LETTER REQUESTING CORRECTIONS / ADDITIONAL INFORMATION Response to Preliminary Approval Response to letter requesting additional information (Please attach a copy of the letter) Final Short Plat Submittal Summary of revision/response submittal: The applicant is providing a response memorandum to address comments received from the City of Tukwila in Correction Letter #1. The project design report and SEPA checklist have been revised and resubmitted based on the comments from the City. Received at the City of Tukwila Permit Center by: ❑ Entered in TRAKiT on C:\Users\breinke\AppData\Local\Microsoft\Windows\NetCache\Content.Outlook\81R3103M\L15-0032 Revision Submittal Form.doc Revised: March 2014 r1 GEOENGINEERS_ 0 Memorandum Plaza 600 Building, 600 Stewart Street, Suite 1700, Seattle, Washington 98101, Telephone: 206.728.2674, Fax: 206.728.2732 www.geoengineers.com To: Valerie Lonneman, City of Tukwila Assistant Planner �," \' ry,: From: Thomas Bannister and Jon Ambrose, GeoEngineers u " " CC: Kurt Schneider, LD Schneider and Associates Nt6 d Date: July 30, 2015 Commun1ent peveiop GEI File: 21493-001-01 Subject: Response to Correction Letter #1; L15-0032, E15-0007 The purpose of this memorandum is to provide responses to the City of Tukwila's (City) Correction Letter #1, dated July 14, 2015. The City sent Correction Letter #1 to Thomas Bannister requesting additional information regarding LD Schneider's Green River Bank Erosion Repair project located at 14900 Interurban Avenue in Tukwila, Washington. The City's Correction Letter #1 includes comments from Dave McPherson of the Public Works Department and Valerie Lonneman of the Planning Department. Below are our responses to the City's comments: Public Works - Dave McPherson 1. State Environmental Policy Act (SEPA) (E15-0007) - GeoEngineers revised the SEPA Checklist per Dave McPherson's comments. 2. Shoreline (L15-0032) a. GeoEngineers recognizes that the USGS identifies the Green River at the site as tidally influenced and we have revised the design report accordingly. b. The existing asphalt trail has been damaged from slope failure and is currently closed. No changes to the existing trail are proposed as part of this project. Under an existing easement with LD Schneider, the City agreed to maintain the trail within 40 feet of the Ordinary High Water Mark of the Green River. This easement agreement is attached to the GeoEngineers Design Report. Because the existing trail is located at the top of the bank and at the landward limits allowed by the easement, future trail realignment is not likely. Following bank grading, the trail may be reinstalled in a similar alignment and surfaced with gravel or asphalt. Planning - Valerie Lonneman 1. SEPA (E15-0007) c. The project will require the following materials: i. Approximately 160 cubic yards of native material will be excavated, stockpiled and returned to the riverbank following installation of the proposed drainage system. ii. Approximately 160 cubic yards of clean river bank fill, as specified on Sheet 2 of the revised project designs, will be acquired from a local aggregate source. iii. Approximately 96 cubic yards of topsoil for planting medium, as specified on Sheet 2 of the revised project designs, will be acquired from a local supplier. Memorandum to City of TuL ,a July 30, 2015 Page 2 iv. Approximately 3 cubic yards of washed and clean drainrock, as specified on Sheet 2 of the project designs, will be acquired from a local aggregate source. v. Approximately 1 cubic yard of quarry spalls as specified on Sheet 2 of the project designs, will be acquired from a local aggregate source. d. The existing asphalt trail has been damaged from slope failure and is currently closed. No changes to the existing trail are proposed as part of this project. Under an existing easement with LD Schneider, the City agreed to maintain the trail within 40 feet of the Ordinary High Water Mark of the Green River. This easement agreement is attached to the GeoEngineers Design Report. Because the existing trail is located at the top of the bank and at the landward limits allowed by the easement, future trail realignment is not likely. Following bank grading, the trail may be reinstalled in a similar alignment and surfaced with gravel or asphalt. e. During construction, the contractor will install necessary erosion controls to prevent sediment from entering the flow of the Green River. The project is located landward of ordinary high water mark (OHWM) and no in -water work is proposed. Construction is scheduled to occur in September 2015 and river flow is expected to be very low with little risk of flow entering the work area. The contractor will deploy necessary erosion and sediment controls in the event of rain during construction. If necessary, the contractor will deploy additional contingency erosion controls, such as straw wattle to comply with state water quality standards. We anticipate that a GeoEngineers Certified Erosion and Sediment Control Lead (CESCL) will provide stormwater management guidance to the contractor during construction. Turbidity in the Green River will be visually monitored during construction. If the project results in a visible plume, the contractor will take immediate corrective action by temporarily stopping earthwork activities and installing additional erosion controls. No turbidity testing is proposed because discharge is not anticipated. Upon the completion of site grading, the contractor will immediately install coir erosion control fabric intended to stabilize the site until vegetation is restored to the bank. f. No endangered plant species are known to occur near the site. Endangered Pacific Salmon occur in the Green River as noted on Page 9 of the SEPA checklist. 2. Shoreline (L15-0032) a. GeoEngineers recognizes that the USGS identifies the Green River at the site as tidally influenced and we have revised our report accordingly. b. The seven mature sycamore trees at the site are extremely valuable to the owner and they will be protected during construction. Because of the lack of available space at the site, it is not possible to protect the mature sycamore per City Code. The contractor will install construction fencing along the landward edge of the work area, waterward of the seven existing sycamore tree following guidance from GeoEngineers. If necessary, the contractor will install 4-foot tall plywood boxes around the trunks of the sycamore trees. During site grading, the contractor will take care when operating equipment in the vicinity of the trees. It is anticipated that the GeoEngineers biologist will be on site observing grading activities in the vicinity of the trees. c. The anticipated area to be revegetated is approximately 4,900 square feet. To restore native riparian vegetation in this area, we recommend the following plant schedule: Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. /1 Memorandum to City of TulkN.-a July 30, 2015 Page 3 Estimated Quantity 12 14 12 12 40 40 40 40 40 d. Common Name Black cottonwood Western red cedar Big leaf maple Pacific dogwood Vine maple Oceanspray Snowberry Western serviceberry Red osier dogwood Scientific Name Size Spacing Populus balsamifera Thuja plicata Acer macrophyllum Corpus nutalli Acer circinatum Holodiscus discolor Symphoricarpos albus Amelanchier alnifolia Corpus sericea 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 24—inch in height 24—inch in height 24—inch in height 24—inch in height 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 5 feet o.c. 5 feet o.c 5 feet o.c 5 feet o.c 5 feet o.c As described above, discharge to the river is not anticipated and turbidity measurement is not proposed. Turbidity will be visually monitored during construction and the contractor will postpone earthwork and take corrective action if a visible sediment plume is observed in the river. e. The owner will maintain the site by removing undesirable vegetation from the site during their routine grounds maintenance regimen. The owner will irrigate newly planted trees/shrubs, on an as -needed basis, from July to October. The owner expects that watering may be required on a weekly basis during the summer. Watering will be completed using a hose or installed irrigation system. f. Monitoring the whole site would require visually estimating the areal cover of the whole site. Estimating areal cover of the entire site may result in some subjectivity whereas, measuring the areal cover along a transect is more objective and repeatable. No revisions to the monitoring methods are proposed unless it is a condition of the City's authorization. Photos will be submitted with annual monitoring reports. GeoEngineers specifies a 100-percent biodegradable coir erosion control blanket. It is our experience that this material does not substantially impact volunteering of plants. The expected functional lifespan of this biodegradable material is less than two years. g. h. Native trees and shrubs will be installed in the disturbed areas of the site as illustrated in Sheet 4 of the revised design plans. Plants may be installed down to the OHWM, depending on the actual area disturbed during construction. Willows are not recommended because of the lack of sufficient hydrology for these species. We have revised our project design report, design plans and SEPA Checklist to reflect the revisions discussed in this memo. Those materials are included in this submittal package. Please contact Thomas Bannister at 206-251-1025 if you need additional information or clarification. Disclaimer. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. GEOENGINEERS Plaza 600 Building 600 Stewart Street, Suite 1700 Seattle, Washington 98101 206.728.2674 July 30, 2015 LD Schneider and Associates 3200 North Central Avenue, Suite 1470 Phoenix, Arizona 85012 Attention: Kurt Schneider Subject: Revised Analysis and Design Report Green River Bank Repair 14900 Interurban Avenue South Tukwila, Washington GeoEngineers File No. 21493-001-01 INTRODUCTION GeoEngineers, Inc. (GeoEngineers) is pleased to present an analysis of site conditions and a design to repair an eroding bank along the Green River adjacent to the property at 14900 Interurban Avenue South in Tukwila, Washington. The location of the site is mapped on Sheet C-1 in Appendix A. The purpose of this report is to support an application to the City of Tukwila (City) for a Shoreline Substantial Development Permit and to the Washington State Department of Fish and Wildlife (WDFW) for a Hydraulic Project Approval (HPA). We prepared this report to comply with the submittal requirements of Tukwila Municipal Code (TMC) 18.44. GeoEngineers submitted the original version of this report to the City on June 24, 2015. Following receipt of comment from the City, detailed in Correction Letter #1, we revised this report to address the City's comments and to provide further clarification regarding the proposed project. GeoEngineers assessed the causes of bank failure and developed multiple design alternatives for consideration by the owner. We also evaluated the permitting considerations of each option. As part of our preliminary work, we completed a site assessment and developed a design to address the mechanisms of bank failure. This report details our methods and findings regarding site conditions, mechanism of failure and presents permit level design drawings to mitigate for bank failure and restore the bank to a functional condition. LD Schneider and Associates July 30; 2615 Page 2 SITE DESCRIPTION AND CONDITIONS The 3.6-acre property (Parcel #3597000006) is located on the left (west) bank of the Green River. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. The parcel is generally flat and the river is not leveed. According to the US Geologic Survey (USGS), the Green River is tidally influenced at this location. Overbank bank flooding is extremely rare, particularly on the left bank of the river. The area of the parcel that is within 200 linear feet of the Ordinary High Water Mark (OHWM) of the Green River is regulated under the City of Tukwila's Shoreline Master Program. The Shoreline designation for the site is Urban Conservancy and the River has a buffer of 100 feet measured from OHWM. The site is also designated as a Fish and Wildlife Habitat Conservation Area per TMC 18.44.090 H. A GeoEngineers biologist made a preliminary site visit on May 13, 2014. In general, the riverbank on the property is vegetated with noxious and invasive Himalayan blackberry. Because of the infestation of Himalayan blackberry and lack of trees, habitat conditions along the riverbank are degraded. GeoEngineers observed evidence of a recent slough of the bank located approximately 100 feet southeast of the commercial building on the property. The recent sloughing resulted in an approximately 10-foot high near vertical escarpment that damaged an existing asphalt trail at the top of the bank. The trail is separated from the parking lot by a landscaping island consisting of grass and a row of seven mature sycamore trees. The biologist also observed water weeping from the bank at the toe of the escarpment. The biologist did not observe environmentally sensitive areas, such as wetlands, during the site reconnaissance. On August 12, 2014, a GeoEngineers geotechnical engineer, river hydrologist, and biologist evaluated slope stability, habitat, and flow conditions at the site. During this site visit, the geotechnical engineer noted that the soil exposed in the riverbank consisted of fine to medium silty sand and silt. This material is typical of alluvium in the Green River valley. Bedrock was observed in the riverbanks upstream (south) of the property. Bedrock is also known to be present (State of Washington Department of Natural Resources [DNR] Geology Maps) on the hillside to the west of the site. DNR maps the local geologic unit as the Puget Group (Tp). The Puget Group consists of sandstone, siltstone, claystone, and coal which is white and very fine grained to gritty. The Tiger Mountain Formation, which consists of light-colored, medium -grained sandstone with siltstone, minor pebble conglomerate, and coal beds, is mapped in isolated outcrops in the river valley. The Renton Formation (Tpr), which is a fine- to coarse -grained sandstone with interbedded siltstone, claystone, and coal, is mapped on the hillside to the west of the site. Alluvial deposits (Qal) are mapped immediately adjacent to the site as comprising the river bed and riverbanks. Alluvium is described as a mix of moderately to poorly sorted granular soils deposited by the river. We completed two subsurface geologic explorations at the top of the recently sloughed area where the trail has become undermined and approximately halfway between this point and the corner of the building. These explorations were performed with a track -mounted drill rig and advanced to a depth of 36.5 feet (at the top of the slough) and 51.5 feet (nearer to the building). Summary logs of our explorations are included as Appendix A. The subsurface conditions at the site is consistent with a glacial channel that was carved into siltstone and sandstone and then partially filled with more recent alluvium from the Green River. We observed the alluvium to consist of very loose to medium dense silty sand to a depth of approximately 35 feet. We r• r• GEOENGINEERS...0 File No. 21493-001-01 0 LD Schneider and Associates July 30, 2015 Page 3 observed the silty sand material to overlie a white to light gray sandstone with fine inclusions of coal layers. We interpret this sandstone to be a part of the Tiger Mountain Formation of the Puget Group. The two borings were terminated within the sandstone. We observed groundwater in the borings at a depth of approximately 12-14 feet below ground surface, which is consistent with earlier observations of groundwater seeping out from the toe of the sloughed surface. MECHANISM OF BANK SLOUGHING Based on our observations at the site and experience in the Green River valley, it is our opinion that the bank sloughing is most likely due to a drawdown failure. This type of failure occurs when high groundwater levels and high river levels saturate the riverbank soil and then the river levels drops or "draws down" faster than the water can drain from the riverbank soil. This creates an imbalance of water pressure. The water pressure pushing the bank from within the soil is no longer balanced by the water pressure from the river and the riverbank is pushed into the river. In our experience, this is the most common riverbank failure mechanism on the lower Green River. Toe erosion is also a failure mechanism that is common on the Green River and often found in conjunction with drawdown failures. Toe erosion will weaken a riverbank but the ultimate failure is triggered by drawdown. At this site, the presence of shallow bedrock makes toe erosion less likely to be a significant contribution to the failure of the riverbank. In addition to site observations, bathymetric data of the channel bottom was obtained from King County. Cross sections of the channel bottom in the vicinity of the site do not show the large scour holes typically evident in areas where toe erosion is a major contributor to slope instabilities. We do not believe toe erosion to be a contributing factor in the of bank sloughing at the site. PROJECT DESIGN We developed a permit -level design to mitigate for the bank sloughing and also to address potential future drawdown failures. Permit level design drawings are included as Appendix B. The design objective was to develop a plan appropriate for the site geology and geometry using techniques and materials most likely to be approved by regulatory agencies and offer long term protection. During preliminary design, we considered bio-engineered and hard engineering approaches. The identified design options are located landward of the OHWM for permitting efficiency. Additionally, we believe work waterward of OHWM is unnecessary because the mechanism of failure is not a result of toe erosion. As such, the project will avoid impacts to aquatic habitat at the site. Riverbank Drainage The project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and native soil. The subsurface drainage system consists of a perforated 4-inch schedule 40 polyvinyl chloride (PVC) pipe that will capture subsurface water along the 165-foot length of the bank repair. Solid 4-inch PVC finger drains set at approximately 20-foot intervals will convey the water from the perforated pipe to outfalls located GEOENGINEERS,...0 File No. 21493-001-01 LD Schneider and Associates July 30 2-015 Page 4 landward of OHWM. Small rock will be installed at the outfalls to protect against erosion. This rock is designed to withstand flows from the pipe and sheer stress of river flows under anticipated conditions. This design will reduce the water pressure upgradient of the riverbank and thereby reduce the potential for future drawdown failures. The project is designed to address the primary cause of bank failure (drawdown) and does not include design elements to protect against toe erosion or scour. We anticipate that a qualified contractor will install the drainage system and restore the bank using a medium-sized track mounted excavator and other support equipment. The project will be completed during WDFW's allowable in water work window, or approximately August 1- August 31. Construction is estimated to take approximately 2 weeks. Because the project is located in the 100-foot buffer of the Green River, TMC 18.44.090 E(4) requires the owner, the specialist of record (GeoEngineers), the contractor and representatives from the City of Tukwila to attend a preconstruction meeting at the site. Per TMC 18.44.090 E(5), GeoEngineers will be retained to monitor construction. We estimate that approximately 420 cubic yards (yd3) of material will be cut and filled to complete the project. 0f this 420 cubic yards of material, approximately 160 cubic yards will be native material that will remain on site and will be incorporated back into the riverbank. It will be necessary to import additional material to achieve the design elevations and grades. This material and the estimated quantities are listed below. Anticipated Material Schedule Approximately 420 yd3 of cut and fill: • Approximately 160 yd3 of native material to remain on site. • Approximately 160 yd3 of imported riverbank fill. • Approximately 96 yd3 of imported topsoil. • Approximately 3 yd3 of 1-inch drain rock. • Approximately 1 yd3 of imported outfall protection. Stability Analysis of Design We analyzed the proposed slope repair using the computer program SLOPE/W (GEO-SLOPE International, Ltd., 2012). The SLOPE/W program evaluates the stability of numerous trial shear surfaces using a vertical slice limit -equilibrium method (Morgenstern -Price). This method compares the ratio of forces driving slope movement to the forces resisting slope movement for each trail shear surface, and presents the ratio as the factor of safety. The program then sorts the trail shear surfaces and identifies the surface with the lowest factor of safety, or the "critical" shear surface. We first analyzed the slope in what was likely its configuration just prior to the slough occurring. Our analysis was based on the subsurface data collected in our explorations and on groundwater conditions consistent with a drawdown condition. For this condition we calculate that the factor of safety is Tess than 1.0. This indicates that the forces driving slope movement exceed the forces resisting slope movement and that the slope would fail. Additionally, the calculated critical shear surface is similar to the observed shear surface of the slough. This result further corroborates our opinion that the bank slough was triggered by drawdown. r ' GEOENGINEERS File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 5 We then analyzed the slope with the proposed repair in place. In this case we calculate that the factor of safety against a drawdown type failure is 1.3, indicating that the forces available for resisting slope movement exceed the forces driving slope movement by about 30 percent. As a point of reference, the United States Army Corps of Engineers (USACE) recommends a calculated factor of safety greater than about 1.0 or 1.1 against drawdown failures. Site Restoration Following installation of the riverbank drainage, the disturbed areas will be restored and enhanced. The design goal for the project is to reconstruct the bank at an approximate pre -slough slope angle, or 2.5:1 slope. However, the slope angle of the bank reconstruction will be established to fit within the site constraints, including avoiding damage to the large sycamore trees atop the bank, limiting disturbance to the root zone and transitioning into the native banks adjacent to the repair. To accommodate this slope angle, the existing asphalt trail at the top of the bank may need to be realigned. The alignment of the trail will be established following restoration of the bank. However, under an existing easement with the property owner, the City will maintain the trail within 40 feet of OHWM. The easement agreement is included as Appendix D. Due to the anticipated sheer force during high flow events in the river, we anticipate that the reconstructed bank will require additional erosion protection. 0ur design includes a biodegradable erosion control fabric designed to withstand sheer stresses under normal flow conditions. The erosion control fabric will also stabilize the bank slope from raveling during heavy rain events. Because the project will be completed landward of OHWM, we do not anticipate temporary or permanent impacts to the aquatic habitat of the Green River. Temporary impacts will be limited to the blackberry and English ivy infested bank above OHWM. No trees will be removed as part of the project. The seven mature sycamores along the top of bank will be protected during construction per the requirements of the Shoreline Substantial Development permit. Because of the proximity of these mature trees to the work area it is not practical to protect the trees in the manner required by TMC 18.44.080 B (10). GeoEngineers recommends that the contractor establish tree protections at the maximum practical distance from the trunks of the sycamore trees to complete the project. We recommend that the contractor install high visibility construction fencing between the work area on the bank and the sycamore trees that are located approximately 15 to 20 feet landward from the top of the riverbank. If necessary that contractor will install 4-foot high plywood boxes around the trunks to further protect the trees. During site grading, the contractor will take care when operating equipment in the vicinity of the trees. It is anticipated that the GeoEngineers biologist will be on site observing grading activities in the vicinity of the trees. The work area is currently infested with Himalayan blackberry which will be removed during construction. The project design includes aggressive revegetation to reestablish root strength and help stabilize the bank. Native plant species will be densely installed in the areas disturbed by the project. Below is a list of recommended plants to be installed at the site to reestablish root structure and appropriate riparian habitat. The estimated plant quantities are based on a 4,900 square foot disturbance area. Installed plant quantities may vary based on the actual disturbance area. GEOENGINEERS2/2 File No. 21493-001-01 ��/ • LD Schneider and Associates July 30; 2015 Page 6 Estimated Quantity 12 14 12 12 40 40 40 40 40 Common Name Black cottonwood Western red cedar Big leaf maple Pacific dogwood Vine maple Oceanspray Snowberry Western serviceberry Red osier dogwood Scientific Name Populus balsamifera Thuja plicata Acer macrophyllum Corpus nutalli Acer circinatum Holodiscus discolor Symphoricarpos albus Amelanchier alnifolia Corpus sericea Size 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 24—inch in height 24—inch in height 24—inch in height 24—inch in height Spacing 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 5 feet o.c. 5 feet o.c 5 feet o.c 5 feet o.c 5 feet o.c We developed this native plant palette based on our experience with riparian restoration and with guidance from WDFW (Cramer, 2012). We increase the density of the installed trees to 10 feet on -center at the request of WDFW (2015). Installed deciduous trees will be 2-inch caliper, conifer will be 6-8 foot height and shrubs will be 24-inch height in compliance with TMC 18.44.080 C(1)(j). Trees will be planted on 10-foot spacing per WDFW's request and shrubs will be planted on 5-foot spacing per TMC 18.44.080 C(2)(d). To enhance aquatic habitat, the GeoEngineers biologist will provide guidance to the contractor in installing the plants in locations that promote shade and overhanging vegetation near OHWM while maintaining the view corridors of the existing riverfront trail. Large trees will be installed outside the drip line of the existing sycamore trees. The planting plan also accounts for the seasonally fluctuating river levels and variable hydrology up the slope of the riverbank. Because of the typical hot and dry conditions during WDFW's allowable work window, we recommend that the revegetation of the riverbank be delayed until late fall. Planting in late summer will likely result in plant failure and poor revegetation. The erosion control fabric installed on the riverbank will stabilize the bank in the interim between repair of the bank and site revegetation. To avoid and minimize water quality impacts during construction, temporary erosion and sediment controls will be installed prior to site work. A silt fence will be installed on the downslope construction limits, near OHWM, as the primary water quality protection. Contingency water quality protections include additional silt fence, silt curtains and straw wattles. Stormwater discharge from the site will be visually monitored. It is not anticipated that there will be a stormwater discharge during construction because of the typically hot and dry conditions during the expected construction period in September 2015. No work will occur waterward of OHWM and construction equipment will not work in the water. Should a problem arise the contractor will postpone earthwork and take corrective action to comply with state water quality standards. We estimate the cost to construct the bank repair to be approximately $65,000. 0ur Project Value documentation is included as Appendix C. GEOENGINEERS� File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 7 Maintenance and Monitoring We anticipate that the riverbank drainage system will require minimal maintenance. Maintenance will include occasional flushing of the system via backwashing from the outfalls. The frequency of this maintenance will be determined on an as needed basis. The restored vegetation on the bank will be managed by the on -site property management staff. We anticipate that the riverbank will be maintained as a part of their routine maintenance regimen. Maintenance will include physical removal of noxious and invasive species that may be detrimental to the restored riparian habitat along the riverbank. These noxious and invasive species include but are not limited to: • Knotweeds (Polygonum spp.) • Butterfly bush (Buddleja spp.) • Himalayan blackberry (Rubus armeniacus) • English ivy (Hedera helix) • Scotch broom (Cytisus scoparius) Use of chemical herbicides to control these species is considered unnecessary and is not recommended. We recommend that the installed plants be watered during the dry season for a minimum of three years following plant installation. This watering should occur during the late summer (July to October) and the frequency shall be determined based on weather conditions and plant performance. We anticipate that the site will be watered using a hose or a temporary irrigation system. Beneficial volunteer plants, such as other native species, will be encouraged at the site. Installed plants that do not survive will be replaced as required by the authorizations from the City of Tukwila and WDFW. We anticipate that a provision of the permit issued by WDFW will require 80 percent survival of installed plants for three years following construction of the project. The City of Tukwila will likely require monitoring of the site for a period of five years following plant installation. To monitor performance of the restored vegetation and to comply with project permits, a qualified biologist will annually monitor the site for a period of five years following construction of the project. To track vegetation performance at the site through the monitoring period, we recommend that the monitoring biologist establish a transect along the bank. Using the line intercept method, the biologist will inventory the number and species of native plants observed within 1 foot of either side of the transect shortly following installation of the plants. The location, orientation and length of this transect will be determined in the field by the biologist. The endpoints of the transect will be marked in the field. The biologist will return to the site on an annual basis to complete the survival inventory at the location of the transect. The biologist will determine annual survival rates which will be used to gauge compliance with WDFW's permit. Our experience has shown that calculating survival rates is problematic because of the inherent difficulty of identifying individual plants as the site matures. We recommend that the biologist also measure the areal cover of beneficial vegetation along the length of the transect. It is our opinion that measuring the areal cover of native plants is a better indicator of site performance, is more repeatable and results in less variability amongst site investigators during the monitoring period. Native volunteer plants will be included in the plant inventory and areal cover measurements for the remainder of the monitoring period. Monitoring will include photo documentation of the site. GEOENGINEERS...111w-^ File No. 21493-001-01 ! LD Schneider and Associates July 42015 Page 8 The biologist will complete monitoring events on an annual basis for five years following plant installation. The findings of each monitoring event will be documented and the owner will submit annual reports to the City of Tukwila and WDFW. NO NET LOSS ANALYSIS AND MITIGATION SEQUENCING Consistent with the City of Tukwila's Shoreline Master Program (SMP), this project will result in no net loss of shoreline ecological function. The project will result in approximately 5,000 square feet of temporary impacts to the shoreline. These impacts are necessary to eliminate the inherent public safety issue posed by the slope failure and to maintain safe, public access to the shoreline on the property. To rectify these unavoidable impacts, the project follows the mitigation sequencing steps identified in TMC 18.44.070 H(3). Because the project is located landward of OHWM, it avoid impacts to the aquatic environment of the Green River. The riparian habitat that will be impacted by the project is heavily degraded and infested with noxious and invasive plants species. The project proposes to restore and enhance the riparian habitat by removing invasive species and installing native trees and shrubs. The owner is committed to maintaining and monitoring the impacted area to ensure the success of the restoration. As a result of these mitigation steps, the project results in no net loss of shoreline ecological function. We estimate that approximately 200 cubic yards of bank material sloughed into the river during a recent drawdown failure. Much of this material has subsequently been eroded and carried downstream by the river. The drawdown failure resulted a 9-foot high vertical escarpment that damaged the existing public access trail. The escarpment poses a safety risk which has resulted in the closure of the trail. To eliminate this safety hazard, the project will add approximately 160 cubic yards of fill material. This fill material is intended to replace a portion of the bank lost as a result of drawdown failure. We consider this amount of fill to be minor and will have no measureable impact to the hydrology, habitat or other shoreline function. REFERENCES Cramer, Michelle L. (managing editor). 2012. Stream Habitat Restoration Guidelines. Co -published by the Washington Departments of Fish and Wildlife, Natural Resources, Transportation and Ecology, Washington State Recreation and Conservation Office, Puget Sound Partnership, and the U.S. Fish and Wildlife Service. Olympia, Washington. WDFW. 2015. Personal Communication between Larry Fisher (WDFW) and Thomas Bannister (GeoEngineers) on June 9, 2015. LIMITATIONS We have prepared this revised report for LD Schneider and Associates for failing bank along the Green River adjacent to the property at 14900 Interurban Avenue South in Tukwila, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the fields of geotechnical engineering, hydrology, and restoration design engineering in this area at the time this report was prepared. The conclusions, recommendations and GEOENGINEER_ File No. 21493-001-01 LD Schneider and Associates July 30, 2015 Page 9 opinions presented in this report are based on our professional knowledge, judgment and experience. No warranty, express or implied, applies to our services and this report. Any electronic form, facsimile or hard copy of the original document (email, text, table and/or figure), if provided, and any attachments should be considered a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Sincerely, Senior Geotechnical Engineer Associate nyurologisi TAB:US:JMA:leh Attachments: Appendix A. Geologic Boring Logs Appendix B. Permit Level Design Drawings Appendix C. Project Value Documentation Appendix D. Trail Easement Agreement One copy submitted electronically Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. GEOENGINEERQ File No. 21493-001-01 0 APPENDIX A Geologic Boring Logs SOIL CLASSIFICATION CHART ADDITIONAL MATERIAL SYMBOLS f1 r-) LJ n ;n fl LJ f I fl t_J tJ n n U n iJ n n v fl MAJOR DIVISIONS SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER COARSE GRAINED SOILS MORE THAN 50% RETAINED ON NO. 200 SIEVE GRAVEL AND GRAVELLY SOILS MORE THAN 50%OF COARSE FRACTION RETAINED ON NO. 4 SIEVE CLEAN GRAVELS (LITRE OR NO FINES) 0 v u c 0 Cy, o ) nC Gw WAD ELL-GRED GRAVELS, GRAVEL -SAND MIXTURES D Q 0 0 0 C 0 0 0 c GP POORLY -GRADED GRAVELS, GRAVEL - SAND MIXTURES GRAVELS WITH FINES (APPRECIABLELSAMOUNT OF GM SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES lir AO GC CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES SAND AND SANDY SOILS MORE THAN 50%OF COARSEFRAC10N PASSING NO. 4 SIEVE CLEAN SANDS (LITRE aft ND FINES) 0 0 0 0 0 0 0 0 0 0 ° SW WELL -GRADED SANDS, GRAVELLY S SP POORLY-G GRARLRADEDSAND SANDS, VELLY SANDS WITH FINES (APPRECIABLE AMOUNT OF FlNEA) $M SILTYSANDS, SAND - SILT MIXTURES SC CLAYEY SANDS, SAND -CLAY MIXTURES FINE GRAINED SOILS MORE THAN 50% PASSING NO. 200 SIEVE SILTS AND CLAYS LIQUID LIMIT LESS THAN 50 ML INORGANIC SILTS, ROCK FLOUR, CLAYEY SILTS WITH SLIGHT PLASTICITY CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL SILTY PLASTICITY SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50 1 1 MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS SILTY SOILS , / ` CH INORGANIC CLAYS OF HIGH PLASTICIN LA/w�-- lu OH ORGANIC TOLAYGSH D SSIICYOF HIGHLY ORGANIC SOILS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS pT NOTE: Multiple symbols are used to indicate borderline or dual soil classifications LI • 11 Sampler Symbol Descriptions 2.4-inch I.D. split barrel Standard Penetration Test (SPT) Shelby tube Piston Direct -Push Bulk or grab Continuous Coring Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (or distance noted). See exploration log for hammer weight and drop. A "P" indicates sampler pushed using the weight of the drill rig. SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER AC Asphalt Concrete CC Cement Concrete CR Crushed Rock/ Quarry Spells TS Topsoil/ Forest Duff/Sod ohm AL CA CP CS DS HA MC MD OC PM PI PP PPM SA TX UC VS NS SS MS HS NT Groundwater Contact Measured groundwater level in exploration, well, or piezometer Measured free product in well or piezometer Graphic Log Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Material Description Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Laboratory / Field Tests Percent fines Atterberg limits Chemical analysis Laboratory compaction test Consolidation test Direct shear Hydrometer analysis Moisture content Moisture content and dry density Organic content Permeability or hydraulic conductivity Plasticity index Pocket penetrometer Parts per million Sieve analysis Triaxial compression Unconfined compression Vane shear Sheen Classification No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen Not Tested NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to be representative of subsurface conditions at other locations or times. KEY TO EXPLORATION LOGS r, GEOENGINEERS FIGURE A-1 Start End Drilled 4/23/2015 4/23/2015 i Total --51.5 Depth (ft) Logged BAW/SST Checked By LJS Driller Holocene Drillil�>Inc. Drilling Hollow Stem Auger Method 0 8 0 0 0 0 8 3 8 0 Surface Elevation (ft) 28 Vertical Datum NAVD88 Hammer Data Auto Hammer 140 (Ibs) / 30 (in) Drop Drilling Equipment Diedrich D50 Truck Rig Easting (X) Northing (Y) System Datum Notes: Groundwater Depth to Date Measured Water (81 See Remarks Elevation (fit I I I I I 1 1 I I I I 1 1 I f I I 1 'o 's c)0 2s Elevation (feet) - o cn o Depth (feet) FIELD DATA Graphic Log Group Classification MATERIAL DESCRIPTION Moisture Content (%) Fines Content (%) REMARKS Interval Recovered (in) 8 0) 3 0 m Collected Sample Sample Name Testing Water Level 2 3 ML Brown silt with sand, occasional organic matter J - (twigs, duff) (soft, moist) 12 4 28 ML _ Brown silt with sand (medium stiff, moist) (alluvium) 118 4 F 21 56 8 3 4A ML Brown silt, trace sand (soft, moist) (alluvium) 48 MC 4B SM Gray silty sand (very loose, moist) (alluvium) 18 5 SA 33 36 Grades to loose, wet J 18 9 6- - Groundwater observed at 14 feet at time of drilling 114 10 7 ill 18 7 8A 8B = ML Gray silt, trace sand (medium stiff, moist) _ (alluvium) = 20—J h - 14 3 �F 57 98 - 25 —J 22 10 — SP-SM _ Gray fine to coarse sand with silt (medium dense, — 16 - wet) (alluvium) - - - 30--] 21 11 12 —•`' - - 35---] 18 25 12 - - Note: See Figure A-1 for explanation of symbols. Log of Boring B-1 G EO E N G I N E E R5 Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-2 Sheet 1 of 2 r• f f• f• r' r• r• t-, ✓ FIELD DATA n lJ n U n n Ll n f1 n u rl fl u 0 0 z N S U W 0 O w O w O 0 c? aJ m 0 0 n 0 0 tJ E F n E iJ � m O n LJ n U 1 � K n U r1 N ♦J Elevation (feet) w r a. 5) 0 - 40� 12 c To N • 5) C � 4). 0 Q7 Collected Sample d E z C E w Water Level 0 V d 0 c 0 U t3. N z 0 @ 0 MATERIAL DESCRIPTION REMARKS - 451 18 '1- 9 501 18 22 50 73 13A 138 14 15 STONE - SAND Sandstone: white; visually fresh; fine grained (Puget Group Tiger Mountain formation) Note: See Figure A-1 for explanation of symbols. Log of Boring B-1 (continued) G EO E N G I N E E R S Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-2 Sheet 2 of 2 Start End Total 66.5 Depth (ft) Logged BFAW/SST Checked By LJS Driller Holocene Drillitt9-4nc. Drilling Hollow Stem Auger Method Drilled 4/23/2015 4/23/2015 Surface Elevation (ft) 28 Vertical Datum NAVD88 Hammer Data 140 (Ibs) / 30 (in) Drop Drilling Diedrich D50 Truck Rig Equipment Easting (X) Northing (Y) System Datum Groundwater Depth to Date Measured Water (ftl Elevation (ftl Notes: See Remarks 0 z yi 0 H 0 m' 0 1- c0� N z z 0 m m E 0 0 0 8 z 8 0 0 U 0 a y 3 e. 6 i i 1 i i i i 1 i i i i 1 1 i i i 1 i i ♦ 'o s Q0 2s Elevation (feet) o 8 'o cn o Depth (feet) I I 1 I I I i i i I I I I I 1 I i i 1 1 I FIELD DATA Graphic Log Group Classification Moisture Content (%) Fines Content (%) Interval Recovered (in) 2 N 3 0 m Collected Sample Sample Name Testing Water Level MATERIAL DESCRIPTION REMARKS 12 3 AC T2 inches asphalt concrete walkway II 1 0 6 4 2 2 SM - Brown silty fine to medium sand (very loose, moist) (alluvium) - 12 118 1 18 1 18 12 18 6 4 10 10 12 2 3B 4 %F 5 6 SA 8A SM Brown silty fine to medium sand (loose, moist) - (alluvium) - Grades to wet _ Grades to medium dense with trace organic - matter (small roots) — = = — 33 33 43 47 Groundwater observed at 12 feet at time of drilling - - h - 22 ML Light gray silt with trace horizontally oriented organic matter (fine fibrous wood fragments) - (soft, moist) (alluvium) - 60 _ _ 25— O - = 30--] y - 1 12 18 23 9 F 10 SP-SM _ Gray fine to coarse sand with silt (medium dense, _ wet) (alluvium) — — - 26 10 Driller indicated different drilling conditions at = 35 18 37 11 SAND STONE Sandstone: white, visuallyfresh, finegrained — (Puget Group Tiger Mountain formation) — approximately 34 feet Note: See Figure A-1 for explanation of symbols. Log of Boring B-2 G EO E N G I N E E R S Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-3 Sheet 1 of 1 r� r1 f • r • t. • t C C C C C C C J C C. 3 C? C _CC i C? C :3 L J 21943-001-00 SST:LJS 04-28-2015 p-v 321f10IJ S11f1S3d SISA1VNV 3A3IS PERCENT PASSING BY WEIGHT 100 90 80 70 60 50 40 30 20 10 0 U.S. STANDARD SIEVE SIZE 3" 1.5" 3/4" 3/8" #4 #10 #20 #40 #60 #100 #200 1000 100 0 10 4 1 GRAIN SIZE IN MILLIMETERS 01 0.01 0.001 BOULDERS COBBLES GRAVEL SAND COARSE FINE COARSE MEDIUM FINE SILT OR CLAY SYMBOL EXPLORATION NUMBER DEPTH (ft) USCS SOIL CLASSIFICATION B-2 B-1 17.5 10 Gray silty sand (SM) Brown silty sand (SM) • r APPENDIX B Permit Level Design Drawings 01\00\CAD \214930 5133rd 5t 'orh A ¢ FOSTER P �37th St 5 140th St 5 140th St st Showalter Middle School Foster Nigh School S 144th 5t St S 146th St 4' 5 150th St rvd 5 160th St 5 156th St S 164th 5t 5 166th St 4' S 139th St ♦ Crystal Springs Part tower calf Swiss a PS S 144th St 5 147th St S 150th St S 152nd St Rds 5 143rd pl LD SCHNIEDER GREEN RIVER BANK REPAIR TUKWILA, WASHINGTON BLACK RIVER 4 5'43rdSt JUNCTION 5 130th St 4 a5 5 Langston Rd 5 Langston Rd 4 S 132ndsr S 732nd sr v. S 132nd Se5132n 5 133rd SC s 134rh se 5 135th 5r Black River Quarry PROJECT SITE C_ 3 Stort CentPark 5 m �r49th S 5 9L P3 S 153rd St rn Tukwila Park 1 Tukwila Via, a uchcen` T"kI5 /4 Pkwy tuk vwiia Pk 3 D c Southcent▪ er Mall 4 Baker Blvd VICINITY MAP SCALE: 1 "=100' • Stranger Blvd Treck Dr GRAPHIC SCALE 1000 1000 FEET CD • Black Meer Riparun forest and Wetland 8 r •7 5 n m J C < R 7',r: Tukwila !aa A = 3 '4 m�v SW 16th 5t SW 27th sr O SHEET INDEX: 1 VICINITY MAP AND SITE MAP 2 NOTES AND SPECIFICATIONS $ SITE PLAN 4 CROSS —SECTIONS 5 DETAILS GRAPHIC SCALE 400 0 400 FEET FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk Rev DESIGNED LJS DRAWN DATE 051,27115. FILE N0. 21493-001-01 TJM CHECKED JMA SCALE AS NOTED .REVISED. 00/00100 GEOENGINEER. LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON VICINITY MAP AND SITE MAP SHEET 1 Q 1- 0 z a 0 z 1- 0 O GENERAL NOTES: 1. THESE DESIGNS AND DRAWINGS HAVE BEEN PREPARED FOR THE EXCLUSIVE USE OF LD SCNEIDER, AND THEIR AUTHORIZED AGENTS. NO OTHER PARTY CAN RELY ON THE PRODUCT OF OUR SERVICES UNLESS GEOENGINEERS INC. (GEOENGINEERS) AGREES IN WRITING IN ADVANCE OF SUCH USE. 2. THE DRAWINGS CONTAINED WITHIN SHOULD NOT BE APPLIED FOR ANY PURPOSE OR PROJECT EXCEPT THE ONE SPECIFIED. 3. THESE DESIGNS AND DRAWINGS ARE COPYRIGHTED BY GEOENGINEERS, INC. ANY USE, ALTERATION, DELETION, OR EDITING OF THIS DOCUMENT WITHOUT EXPLICIT WRITTEN PERMISSION FROM GEOENGINEERS IS STRICTLY PROHIBITED. ANY OTHER UNAUTHORIZED USE OF THIS DOCUMENT IS PROHIBITED. 4. THE CONTRACTOR SHALL CONSTRUCT THE PROJECT IN ACCORDANCE WITH THE PLANS STAMPED "APPROVED FOR CONSTRUCTION." THESE PLANS WILL BE PROVIDED TO THE CONTRACTOR BY THE ENGINEER OR PROJECT INSPECTOR PRIOR TO CONSTRUCTION. WORK SHALL NOT BE INITIATED WITHOUT THE PLANS APPROVED FOR CONSTRUCTION. 5. THE DESIGNS DEPICTED HEREIN ARE APPROXIMATE AND ARE INTENDED TO EXPRESS THE OVERALL DESIGN INTENT OF THE PROJECT. THESE DESIGNS MAY NEED TO BE ADJUSTED IN THE FIELD DURING CONSTRUCTION IN ORDER TO MEET THE SPECIFIC SITE CONDITIONS AND INTENDED FUNCTION. THESE RIVER IMPROVEMENTS HAVE BEEN DEVELOPED WITH THE UNDERSTANDING THAT A QUALIFIED GEOENGINEERS ENGINEER AND/OR SCIENTIST BE ON -SITE TO PROVIDE CONSTRUCTION GUIDANCE WHILE THE PROJECT IS CONSTRUCTED. 6. CONDITIONS CAN CHANGE AND THESE DESIGNS ARE BASED ON CONDITIONS THAT EXISTED AT THE TIME THE DESIGN WAS PERFORMED. THE RESULTS OF THESE DESIGNS MAY BE AFFECTED BY THE PASSAGE OF TIME, BY MANMADE EVENTS SUCH AS CONSTRUCTION ON OR ADJACENT TO THE SITE, OR BY NATURAL EVENTS SUCH AS FLOODS, EARTHQUAKES, SLOPE INSTABILITY OR GROUNDWATER FLUCTUATIONS. ALWAYS CONTACT GEOENGINEERS BEFORE APPLYING THESE DESIGNS TO DETERMINE IF THEY REMAIN APPLICABLE. 7. THESE PLANS AND ELECTRONIC DRAWINGS ARE BASED ON WASHINGTON STATE PLANE NORTH COORDINATES US FEET AND A NORTH AMERICAN VERTICAL DATUM OF 1988 US FEET. ELEVATIONS AND NORTHINGS AND EASTINGS WITHIN THIS PLANSET ARE BASED ON THESE DATUMS. CONSTRUCTION NOTES: 1. CONTRACTORS WORKING WITHIN THE PROJECT BOUNDARIES ARE RESPONSIBLE FOR COMPLIANCE WITH ALL APPLICABLE SAFETY LAWS. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL BARRICADES, SAFETY DEVICES AND CONTROL OF TRAFFIC WITHIN AND AROUND THE CONSTRUCTION AREA. 2. MATERIAL AND WORKMANSHIP FURNISHED ON OR FOR THE PROJECT MUST MEET THE MINIMUM REQUIREMENTS OF PROJECT PERMITS, APPROVING AGENCIES, SPECIFICATIONS AS SET FORTH HEREIN, OR WHICHEVER IS MORE RESTRICTIVE. 3. THE CONTRACTOR SHALL INSTALL AND MAINTAIN APPROPRIATE SEDIMENT CONTROL DEVICES THROUGHOUT THE WHOLE PROJECT SITE, INCLUDING THE CONSTRUCTION STAGING AREA AND STOCKPILE AREA THROUGHOUT THE PROJECT'S CONSTRUCTION. TEMPORARY CONSTRUCTION AND PERMANENT EROSION CONTROL MEASURES SHALL BE DESIGNED, CONSTRUCTED AND MAINTAINED IN ACCORDANCE WITH APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS. 4. CONSTRUCTION SHALL OCCUR DURING THE APPROVED WDFW FISH WINDOW FOR THE PROJECT AREA. 5. DISCHARGES ENTERING ACTIVE STREAMS ON -SITE SHALL SATISFY ALL STATE AND FEDERAL STANDARDS AND PROJECT PERMIT REQUIREMENTS FOR CONTAMINANTS AND TURBIDITY. SPECIFICATIONS: A. REFERENCED SPECIFICATIONS ARE FROM THE 2014 VERSION OF THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION. MATERIALS: A. RIVERBANK FILL 1. RIVERBANK FILL SHALL CONSIST OF WELL GRADED SAND AND GRAVEL CONFORMING TO EITHER WSDOT STANDARD SPECIFICATION 9-03.10 "AGGREGATE FOR GRAVEL BASE", 9-03.12(2) "GRAVEL BACKFILL FOR WALLS", 9-03.13(1) "GRAVEL BORROW", 9-03.13(2) "SELECT BORROW", OR OTHER MATERIALS AS APPROVED BY THE GEOTECHNICAL ENGINEER. NATIVE ALLUVIUM FROM THE EXISTING RIVERBANK MAY BE INCORPORATED INTO THE RIVERBANK FILL PROVIDED THAT THE ALLUVIUM CONTAINS LESS THAN 30 PERCENT FINES (MATERIAL PASSING THE NO. 200 SIEVE) BY WEIGHT OR AS APPROVED BY THE GEOTECHNICAL ENGINEER. 2. RIVERBANK FILL SHALL BE FREE OF ORGANICS OR OTHER DELETERIOUS MATERIALS. B. DRAINAGE ROCK 1. DRAINAGE ROCK SHALL MEET WSDOT STANDARD SPECIFICATION 9-03.12(2) "GRAVEL BACKFILL FOR WALLS." C. DRAIN PIPE 1. DRAIN PIPE SHALL CONSIST OF 4-INCH SCHEDULE 40 PVC PIPE. THE PIPE SHALL BE SOLID OR PERFORATED AS INDICATED ON THE PROJECT PLANS. THE PIPE AND CONNECTIONS SHALL MEET AASHTO SPECIFICATION M 278. PIPE CONNECTIONS AND DETAILING SHALL BE IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. 2. PERFORATED DRAIN PIPE INSTALLED PARALLEL TO THE SLOPE AND SHALL CONNECT TO SOLID DRAIN D. 1. PIPES (OUTLET DRAINS) THAT DAYLIGHT TO THE SLOPE FACE. SOLID DRAIN PIPES SHALL BE SPACED NO MORE THAN 20 FEET APART. SOLID DRAIN PIPES SHALL DISCHARGE ON AN EROSION PROTECTION PAD OR EXTEND TO THE BASE OF THE EXISTING SLOPE. EROSION PROTECTION PADS SHALL BE CONSTRUCTED OF MATERIAL CONFORMING TO WSDOT STANDARD SPECIFICATION 9-03.9(2) "PERMEABLE BALLAST". THE EROSION PROTECTION PADS SHALL BE FIELD FIT BY THE ENGINEER AT THE DISCHARGE LOCATIONS AND SHALL HAVE A MINIMUM THICKNESS OF 6-INCHES, MINIMUM LENGTH (PARALLEL TO SLOPE) OF 2 FEET, AND MINIMUM WIDTH (PERPENDICULAR TO SLOPE) OF 1 FOOT. NON -WOVEN GEO-TEXTILE NON -WOVEN GEO-TEXTILE SHALL MEET WSDOT STANDARD SPECIFICATION 9-33.1 "GEOSYNTHETIC MATERIAL REQUIREMENTS" FOR NON -WOVEN GEO-TEXTILES USED FOR SEPARATION. E. RECYCLED MATERIAL 1. RECYCLED MATERIAL SHALL NOT BE USED IN AGGREGATES OR FILL. F. TOPSOIL 1. TOPSOIL SHALL CONSIST OF A COMMERCIALLY AVAILABLE 3-WAY MIXTURE CONSISTING OF LOAM SOIL, ORGANICS AND COMPOST PASSING '-INCH SIEVE. G. EROSION CONTROL BLANKET AND STRAW WATTLES 1. EROSION CONTROL BLANKET SHALL COMPLY WITH WSDOT STANDARD SPECIFICATION 9-14.5(2)D "BIODEGRADABLE EROSION CONTROL BLANKET FOR DITCHES. THE EROSION CONTROL BLANKET SHALL BE 100-PERCENT BIODEGRADABLE COIR WITHOUT MESH BACKING. THE EROSION CONTROL BLANKET SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. 2. STRAW WATTLE OR SIMILAR SHALL BE 100% BIODEGRADABLE. STRAW WATTLES SHALL BE APPROVED BY GEOENGINEERS PRIOR TO INSTALLATION. EXECUTION: A. SUBGRADE PREPARATION 1. SUBGRADES SHALL BE CLEARED AND GRUBBED. REMOVE BRUSH, SOD, OR OTHER ORGANIC OR DELETERIOUS MATERIALS PRIOR TO THE PLACEMENT OF FILL. SOFT AREAS SHALL BE OVEREXCAVATED AND REPLACED, AS DIRECTED BY GEOTECHNICAL ENGINEER. 2. SUBGRADE SHALL BE APPROVED BY GEOTECHNICAL ENGINEER. SUBGRADE SOILS SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION BEFORE CONSTRUCTION PROCEEDS. SUBGRADE MATERIALS NOT MEETING GEOTECHNICAL ENGINEER'S APPROVAL SHALL BE REMOVED AND REPLACED WITH RIVERBANK FILL AT DIRECTION OF GEOTECHNICAL ENGINEER. 3. OVEREXCAVATED AREAS SHALL BE REPLACED WITH COMPACTED RIVERBANK FILL MATERIAL. B. SLOPE PREPARATION 1. EXISTING SLOPES SHALL BE RE -GRADED AS REQUIRED TO INSTALL SPECIFIED IMPROVEMENT AND TO MAINTAIN A SAFE WORK ZONE. THE CONTRACTOR IS RESPONSIBLE FOR MAINTAINING A SAFE WORK ZONE AND COMPLYING WITH THE PROVISIONS OF TITLE 296 WASHINGTON ADMINISTRATIVE CODE (WAC), PART N, "EXCAVATION, TRENCHING AND SHORING." 2. FILL PLACED ON OR ADJACENT TO SLOPES SHALL BE PLACED ON HORIZONTAL BENCHES CUT INTO THE EXISTING SLOPE. 3. BENCHES SHALL EXTEND A MINIMUM OF 2-FEET HORIZONTALLY INTO THE SLOPE AND MAY BE CUT IN STAGES AS THE FILL PROGRESSES. C. FILL PLACEMENT AND COMPACTION 1. FILL MATERIAL SHALL BE PLACED IN LOOSE LIFTS NOT EXCEEDING 12-INCHES AND COMPACTED USING EQUIPMENT DESIGNED FOR SOIL COMPACTION. 2. FILL SHALL BE UNIFORMLY COMPACTED TO A MINIMUM 90 PERCENT OF MAXIMUM DRY DENSITY (MDD) AS DETERMINED BY ASTM D-1557. D. SITE REVEGETATION 1. TOPSOIL SHALL BE LOOSELY PLACED ABOVE THE RIVERBANK FILL TO A DEPTH OF 12 INCHES. THE FINISH GRADE SHALL BE TAMPED FIRM AND PROTECTED FROM EROSION. 2. THE EROSION CONTROL BLANKET SHALL BE SHINGLED OR PLACED IN A MANNER SUCH THAT RIVER FLOWS AND WIND DO NOT PEEL UP THE FABRIC. THE EROSION CONTROL FABRIC SHALL BE ANCHORED FOLLOWING THE MANUFACTURER'S INSTRUCTION. 3. NATIVE PLANTS, IDENTIFIED IN THE PLANT SCHEDULE, SHALL BE INSTALLED FOLLOWING THE LAYOUT PROVIDED BY THE GEOENGINEERS BIOLOGIST. PLANTS SHALL BE INSTALLED THROUGH THE EROSION CONTROL FABRIC BY CUTTING THE FABRIC TO THE MINIMUM NECESSARY TO INSTALL THE PLANTS. E. SITE MAINTENANCE AND MONITORING 1. THE SITE WILL BE MAINTAINED BY THE OWNER INTO PERPETUITY AND IN COMPLIANCE WITH THE PROJECT PERMITS. 2. THE SITE WILL BE MONITORED FOR A PERIOD OF FIVE YEARS FOLLOWING PLANT INSTALLATION AS SPECIFIED IN THE DESIGN AND ANALYSIS REPORT BY GEOENGINEERS OR AS REQUIRED BY THE PROJECT PERMITS. ANTICIPATED MATERIAL SCHEDULE APPROXIMATELY 420 YD3 OF CUT AND FILL: • ,-160 YD3 OF NATIVE MATERIAL TO REMAIN ON SITE. • -160 YD3 OF IMPORTED RIVERBANK FILL. • YD3 OF IMPORTED TOPSOIL. • -3 YD3 OF 1-INCH DRAIN ROCK. • --1 YD3 OF IMPORTED OUTFALL PROTECTION. FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date ' By Chk Rev REVISION PER AGENCY COMMENTS 7-22-15 TJM TAB LJS DESIGNED LJS DRAWN TJM DATE 05/27/15 FILE N0. 21493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 GEOENGINEERS.g 600 Stewart Street, Suite 1700 P: 206-728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON NOTES AND SPECIFICATIONS SHEET 2 OHWM OHWM ASPHALT TRAIL 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER COMMERCIAL BUILDING LEGEND B-1 -4- BORING LOCATIONS' 4S - - - — EXISTING CONTOURS PROPOSED BANK LINES OHM ORDINARY HIGH WATER MARK LIMITS OF WORK SILT FENCE . BORING LOGS PROVIDED IN ACCOMPANYING REPORT (GEOENGINEERS 2015) VERTICAL DATUM: NAVD88 STONE BENCH OHWM GREEN RIVER OH WM EL=10.0' OHWM OHWM OHWM STONE BENCH 34" SYCAMORE PLAN VIEW SCALE: 1 "=10' 24" SYCAMORE SCALE 10 0 10 FEET i--5— OUTLET DRAIN (TYP.) OHWM BOTTOM OF FILL SLOPE r— SILT FENCE OHWM DRAIN PIPE p ARK1NG LOT / OHWM - OHWM OtOg' OHWM ZC- - / J l/ —1 ASPHALT TRAIL SYCfMORE i 24" SYCAMORE TOP OF EXISTING SLOPE 41" SYCAMORE PROTECT TREES PER CITY REQUIREMENTS (TYP.) OMA FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date By Chk Rev 01\00\CAD\21493 DESIGNED LJS DRAWN TJM CHECKED JMA DATE 05/27/15 SCALE AS NOTED FILE NO. 21493-001-01 REVISED: 00/00/00 GEOENGINEERS 600 Stewart Street. Suite 1700 P: 206-728-2674 Seattle, WA 98101 F. 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON SITE PLAN SHEET 3 :SECTIONS MODIFIED BY TMICHAUD ON JUL 22, 2015 - I P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETS.DWG T SCALE 5 5 FEET 24" SYCAMORE (PROTECT TREE PER GEOENGINEERS) I-- PARKING LOT 30 — 20- 10 — 0 1� LANDWARD LIMITS OR WORK 1 EXISTING 1 — ASPHALT TRAIL SEE ANCHOR TRENCH DETAIL -11 CUT AS REQUIRED FOR SAFETY AND STABILITY 2% SEE DRAIN DETAIL OUTLET DRAIN — SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) TOP SOIL ,— EXISTING GRADE RIVERBANK FILL NATIVE VEGETATION (TYP.) EROSION CONTROL FABRIC 2.5 OUTFALL PROTECTION PER MATERIAL NOTE C-2 BASE FLOOD ELEVATION SILT FENCE (WATERWARD LIMITS OF WORK) OHWM — 30 —20 10 30" SYCAMORE (PROTECT TREE PER GEOENGINEERS) 30 20 — 10 - 0 PARKING LOT 20 30 SECTION 40 Distance (Feet) 50 60 A HORIZONTAL SCALE 1"=5' VERTICAL SCALE: SEE ANCHOR TRENCH DETAIL CUT AS REQUIRED FOR SAFETY AND STABILITY SEE DRAIN DETAIL LANDWARD LIMITS OR WORK EXISTING ASPHALT TRAIL C-2 NATIVE VEGETATION (TYP.) EXISTING GRADE TOP SOIL 70 80 — 30 RIVERBANK FILL — EROSION CONTROL FABRIC — BASE FLOOD ELEVATION OUTFALL PROTECTION PER 2.5 MATERIAL NOTE C-2 — 1 SEE ANCHOR TRENCH DETAIL 40' TRAIL EASEMENT (APPROXIMATE) SILT FENCE (WATERWARD LIMITS _ OF WORK) OHWM 0 10 20 SECTION 30 40 Distance (Feet) 50 B HORIZONTAL SCALE: 1,5' VERTICAL SCALE: 1'=5' C-2 60 70 80 10 0 10 0 85 FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dole By Chk Rev REVISION PER AGENCY COMMENTS 7-22-15 TJM TAB WS DESIGNED LJS DRAWN TJM DATE 05/27/15 FILE NO. 21493-901-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 GEOENGINEERS 600 Stewort Street, Suite 1700 P: 206--728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON CROSS -SECTIONS AND DRAIN DETAIL SHEET 4 P:\21\21493001\00\CAD\21493001-01 DESIGN SHEETS.DWG\TAB:DETAILS MODIFIED BY TMICHAUD ON JUL 21, 2015 - 13:09 4" SCH40 PERFORATED PVC DRAIN PIPE EL. 15.0' RIVERBANK FILL 12" DRAIN DETAIL NON -WOVEN GEOTEXTILE SOLID SCH40 PVC OUTLET DRAIN 2% NATIVE SOIL NOT TO SCALE JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATTACH FABRIC TO POSTS. ill IIIJL_;7;;I rllTll_Ili�ll AIII>TIIl-\ 6' MAX. \ MINIMUM 4"x4" TRENCH / BACKFILL TRENCH WITH NATIVE SOIL OR 3/4"-1.5" POST SPACING MAY BE INCREASED WASHED GRAVEL TO 8' IF WIRE BACKING IS USED 2"x2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBLE Recommended Planting Schedule Estimated Quantity Common Name Scientific Name Size Spacing 12 Black cottonwood Populus balsamifera 6 - 8 feet in height 10 feet o.c. 14 Western red cedar Thuja plicate 6 - 8 feet in height 10 feet o.c. 12 Big leaf maple Acer macrophyllum 6 - 8 feet in height 10 feet o.c. 12 Pacific dogwood Cornus nutalli 6 - 8 feet in height 10 feet o.c. 40 Vine maple Acer circinatum 6 - 8 feet in height 5 feet o.c. 40 Oceanspray Holodiscus discolor 24-inch in height 5 feet o.c 40 Snowberry Symphoricarpos albus 24-inch in height 5 feet o.c 40 Western serviceberry Amelanchier alnifolia 24-inch in height 5 feet o.c 40 Red osier dogwood Cornus sericea 24-inch in height 5 feet o.c PLANT SCHEDULE 2"x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT SILT FENCE DETAIL EXCESS SOCK MATERIAL, DRAWN IN AND TIED OFF AT STAKE (TYP.) DISTURBED AREA 10' (MAX) DISTURBED AREA SECTION PLAN VIEW 10' - 0" ® 30" ANGLE EACH END TO PREVENT FLOW AROUND (TYP.) 2"X2" X 3' WOODEN STAKE COMPOST SOCK - SEE NOTE 1 CONTOUR LINE (TYP.) 2'X 2'X 3' WOODEN STAKE, SPACED EVERY 3' 0.C. (TYP.) DETAIL NOTES: 1. COMPOST SOCK SHALL BE IN ACCORDANCE WITH STANDARD SPECIFICATION 9.14.4(9). COMPOST SOCK SHALL BE A MINIMUM OF 10" IN DIAMETER OR SIZED TO SUIT CONDITIONS AS SPECIFIED BY THE ENGINEER. 2. ALWAYS INSTALL COMPOST SOCK PERPENDICULAR TO SLOPE AND ALONG PROTECTED CONTOUR LINES. AREA (SHOWN AS SLOPE PROTECTION) 3. REMOVE SEDIMENT FROM THE UP SLOPE SIDE OF THE COMPOST SOCK WHEN ACCUMULATION HAS REACHED 1/2 OF THE EFFECTIVE HEIGHT OF THE COMPOST SOCK. 4. MAY BE USED IN PLACE OF FILTER FENCE FOR PERIMETER CONTROL. STRAW WATTLE DETAIL NOT TO SCALE NOT TO SCALE EROSION CONTROL FABRIC LOOSEN AND/OR CUT CIRCLING ROOTS IN ROOT BOUND CONTAINERS BEFORE PLANTING BREAK UP SIDES AND BOTTOMS OF PLANTING PIT TO ALLOW FOR ROOT PENETRATION COMPACT SUBGRADE BELOW ROOT BALL TYPICAL PLANTING DETAIL FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date By Chk Rev Q REVISION PER AGENCY COMMENTS 7-22-15 TJM TAB LJS DESIGNED LJS DRAWN TJM DATE 05/27/15 (FILE NO. 21493-001-01 CHECKED JMA SCALE AS NOTED REVISED: 07/22/15 �s SpSEPy Sw `Y' of WASy. �0 i � ro rP Pr oljt`'s GEOENGINEERQ 600 Stewart Street, Suite 1700 P: 206-728-2674 Seattle, WA 98101 F: 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON DETAILS SHEET 5 APPENDIX C Project Value Documentation l LB Schneider Green River Bank Repair - Project Value Documentation 14900 Interurban Avenue South Tukwila, Washington Description Description of Quantity QTY per foot of repair Unit Unit Cost (Total + 0&P) Total for Foot of Repair Project Total Based on 160 Feet of Repair Excavation and Haul Riverbank Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY $17.00 $0.00 $0.00 Subtotal Subsurface Drainage Fabric Laid in Trench RS Means 1.3 SY $2.42 $3.15 $503.36 Drainage Material RS Means 0.22 CY $34.00 $7.48 $1,196.80 6-in PVC Perforated RS Means 2 LF $14.45 $28.90 $4,624.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0.126 TON $48.00 $6.05 $967.68 Subtotal $42.43 $6,788.48 Foundation Preparation Foundation Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY $17.00 $0.00 $0.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0 TON $48.00 $0.00 $0.00 Subtotal $0.00 $0.00 Fill Placement and Compaction Gravel Borrow Including Haul and Compaction Bid Tab 1075 from B&D Levee Project 5.53 TON $20.00 $110.60 $17,696.00 Geo-Grid Soil Reinforcement RS Means 0 SF $0.81 $0.00 $0.00 Jute Mesh Bid Tab 8025 from B&D Levee Project 0 SY $1.30 $0.00 $0.00 Subtotal $110.60 $17,696.00 Erosion Control, Surface Treatments, and Plantings TESC Bid Tab Schedule VII B&D Levee 1 LF of River $51.28 $51.28 $8,204.80 Landscaping Bid Tab Schedule VIII B&D Levee 1 LF of River $100.00 $100.00 $16,000.00 Subtotal $151.28 $24,204.80 Mobilization, Contingency, Misc., and Totals Total Unit Costs $262 $41,901 Mobilization Assumed Values 10.0% LS $26 $4,190 Contingency Assumed Values 15.0% LS $39 $6,285 Miscellaneous Costs Assumed Values 10.0% LS $26 $4,190 Sales Tax Washington State 9.5% LS $25 $3,981 Estimated Totals $378 $60,547 0 APPENDIX D Trail Easement Agreement • r ..• !• . 7 • • 1.•-' EASEMENT 4 , •• • PropoSed16-20-79 • 14F:#70417SMO- na THIS INSTRUMENT made this day of 044)(4,414ye- , ,19111°. ., • hy.Gary A. Nilsen Sr,. and L.O. Schneidei. (the "Granto s").-in favor of CITY OF'• • • TUKWILA, a muniCipal corporation of King County, State .of Wishing* (the %mane"). - WITNESSETH • • . , . .GrantOrs, for and in consideration of the sum of one dollar (1.00) and -other 171: valuable consideration, receipt of which is acknowledged, Grantors grants,. -con, rl Neys', and-conf-rms to Grantee, its successors and assigns, a perpetual non-exclusive -, easement -for public.acteis for the purpose of constructing and operating'a recreational l_J. CD trail open to the public,. and related construction and improvements, across and upon the property described on the attached "Exhibit A" and further shown on the map attached as "Exhibit II". -00 Grantee shall have the right without prior institution of suit or proceeding at law, at such time as may be deemed appropriate by Grantee, to enter upon said property for the purpose of operatingmaintaining, repairing, replacing.or re- fl • constructing a public. recreational trail and related improvements, without incur- ring legal obligations or liability therefor: provided, said operating. Maintain- ing, repairing, replacing, or reconstructing of a.public recreational trail or related improvements shall be accomplished in such a manner that private improve- r- ments shall not be disturbed or destroyed. and Grantors shall not be excluded from . such easement property and shall have unlimited right to use said easement property for any lawful purposes not inconiistant with the rights of grantee. In the event they are disturbed or destroyed, they will be replaced in as good a condition. . as they.were immediately before the property was entered upon by Grantee. This -shall be a covenant running with the land forever and shall be binding on GrantorsSuccessors; heirs and assigns. n n fl By: i% EXOSE 'FAX NO1 REQUIRED • Hing Co ftecord.o Division 81. Depiny. I N1.1-hskti,ste:IR'efl.4111 s • . • . • • • ..••• c ,• s' ..;••• :•••••!.• r• • f EXHIBIT A Tfie•pedestrian access easement as, described in the easement agreement shall:be., from the ordinary•high water mark to a point 40 feet west of said -ordinary high water mark over. 'all of the' following parcels, of land: • •LEGAL.DESCRIPTIONS: • That portion of Tract,1, Interurban Addition to -Seattle, according to the' plat.recorded in Volume 10 of'Plats, page 55, records of King County, - Washington, lying southerly of a line which extends northeasterly,,perpen- dicular with the westerly line of said tract, from a point•on said westerly,' line which is 685 feet southeasterly from the northwest corner of said 'tract; and lying northerly of a line which extends northeasterly, perpen- dicular with the westerly line of said tract, from a point on said westerly line'which•is 1555 feet southeasterly from the northwest corner.of said tract;'ALSO that,portion of the vacated Puget Sound Electric Railway R/W adjoining'thereto lying southeasterly of S. 149th St. as conveyed by Puget Sound Power and Light Co. to the City of Tukwila by deed dated October 25,4965 and filed under Auditor's File No. 6557639; and lying northwesterly of a line which extends southwesterly, perpendicular with the easterly line of said P. S. E. R/W, which is also the westerly line of said Tract 1, Interurban Addition, from a point on said westerly 'line ,hick is 1555 feet southeasterly -from the northwest corner of said tract. ;1; ip•7yq� ?y��Y"4 1.: :t1 '}:k=-i%}•�?�t4.#�} .':STATE OF:;WASHINGTON) ss. COUNTY OF. KING ) On this % day Of ��- k'.1 / l�-•� ; before.•me .personally :appeared ;- 4. J-� and. '.._�� �t. . :"•to the known t"6 be � -ter. Q•=��..a � the- . • • of• • .mac �^� w� .s�."9�� - Ai,' .,the•individuals that executed the foregoing instrument, nd acknowledged the`said instrument to be the free and voluntary act and deed of said individuals for -the .uses and purposes mentioned therein, and on oath stated that they were authorized to execute the'said instrument. s�lc NOTARY PUBLI in and fgr`'the to of Wash- ington, res d'ng at /: ,...1 -2- ea'; 4 1� 4uS3zM-4 ri•-i itll • :1r4• .71 ., .,' • Lr 1 T /,`ae► r 7JtYfI' tp' r • i 1 1 r ; • y;41. • V• O V „tr.? • 1J n • 1/40 3x? 5S r� { . PA1 • E1LED tor. !Word at rteqtiest ,ot `U \. City of Tukwila Jim Haggerton, Mayor Department of Community Development Jack Pace, Director July 14, 2015 GeoEngineers, Inc. Attn: Thomas Banister 600 Stewart Street, Suite 1700 Seattle, WA 98101 tban nister @ geoengineers.com Subject: Correction Letter #1 Green River Bank Erosion Repair L15-0032, E15-0007 Dear Mr. Banister: The City is in the process of reviewing your applications for Shoreline Substantial Development and SEPA permits to install a subsurface drainage system and restore an eroded bank on the Green River located at 14900 Interurban Ave. South. Please address the following comments and resubmit relevant documents. Departmental comments are listed below along with reviewer contact information: Public Works —Dave McPherson (206) 431-2448: SEPA — E15-0007 The Environmental Checklist should be revised as follows: B. Environmental Elements 5. Animals c. Yes — This area is part of the Pacific Flyway. A primary corridor for migratory bird species. SHORELINE — L15-0032 Ref. GeoEngineers Report dated June 18, 2015 - Pgl, Site Description - The river is tidally influenced at this point at the uppermost point. Revise the document: Yes — work is at approximately river mile 11.4 and the title influence from recent Green River studies extends as far as river mile 12. USGS considers 200th Street in Kent (river mile 17) to be the spatial extent of the tidal influence. Page 5 of GeoEngineers Report 1st paragraph states "To accommodate this slope angle, the existing asphalt trail at the top of the bank may need to be realigned". Will the trail be replaced and will it have the same alignment? W:\Users\Valerie\SEPA\E15-0007 Green River Bank Repair\Correction Letter #1 Page 1 of 2 6/24/2015 Thomas Banister Green River Bank Erosion Repair L15-0032/E15-0007 Building —Allen Johannessen (206) 433-7163: No comments at this time,. Fire —Don Tomaso (206) 971-8723: No comments at this time. Planning —Valerie Lonneman (206) 433-7140: SEPA — E15-0007 • Pg3e — Provide answer • Pg4g — Discuss trail in impermeable section • Pg4h — Provide details of erosion control and contingencies • Pg4c — Salmon are endangered and near the sight SHORELINE — L15-0032 • Pg1, Site Description - The river is tidally influenced at the uppermost point. Revise the document to reflect this. • Pg5 — Please provide details of the proposed Tree Protection if it will vary from the code. • Pg5 — Please provide the approximate square footage of the project (to verify for tree count). • Pg6 — Erosion control details should be provided, both for proposed and contingency. When will you determine if contingency is needed? Do you plan to do turbidity testing? • Pg6 — Please provide a maintenance plan/detail from the building owner. How often? Watering? etc. • Pg6 — Watering is needed for first three years from at least July to October, depending on conditions. How will the site be watered? • Pg7 — Given the small size of the site, is it possible to monitor the whole site in lieu of establishing a transect? Photos will be required. Additional comments: • Please provide more information on how the fabric will affect recruitment? How long does it take to break down? Is mulch to be used? • Please provide diagram of planting extent — how far toward OHW will you plant? Consider using willow stakes at base of slope. Please feel free to contact me with any questions at (206) 433-7140. Sincerely, 7/l%y Valerie Lonneman Assistant Planner Page 2 of 2 City of Tukwila Jim Haggerton, Mayor Department of Community Development Jack Pace, Director July 16, 2015 Thomas Bannister GEO Engineers 600 Stewart Street, Ste# 1700 Seattle WA 98101 RE: Notice of Application — Green River Bank Repair File# PL15-0027, L15-0032 & E15-0007 Shoreline and SEPA Subsurface Drainage System Dear Mr. Bannister: r There is a fee due on your permit application in the amount of $399.00 to cover fees associated with mailing the attached public notice - Notice of Application, Shoreline and SEPA The number of required notices sent for your application was 399 which included property owners and tenants within 500 feet of your project site as well as interested parties and agencies with jurisdiction. The cost is based on the land use fee schedule adopted by Resolution Number 1845 covering Public Notice mailings required for your application. This fee covers the attached notice only. Additional fees may be assessed for future mailings or other review tasks per the fee schedule. This amount needs to be paid before the city can continue processing your permit application. The payment may be paid by cash, check or credit card. The city will accept credit card payments by phone. If paying by check please send the check made out to: City of Tukwila Attn: Teri 6300 Southcenter Blvd, Ste 100 Tukwila, WA 98188 If you have any questions, please feel free to contact me at Teri.Svedahl@TukwilaWA.gov Sincerely, Teri Svedahl Administrative Support Technician Cc; Valerie Lonneman, City Planner MD Invoicing Public Mailings.doc Page 1 of 1 07/15/2015 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone 206-431-3670 • Fax: 206-431-3665 1 f� /0400 TO: City of Tukwila Department of Community Development RECEIVF !JUL 02 2015 TUKW�- PUBLIC WORK' File Number E15-0007 (SEPA) L,15-0032 (Shoreline) LAND USE PERMIT ROUTING FORM Building ❑i Planning -Public Works Fire Dept. ❑! Police Dept. C Parks/Rec Project: Green River Bank Erosion Repair Address: 14900 Interurban Ave S., Tukwila, Washington Date transmitted: July 1, 2015 Response requested by: July 15, 2015 Staff coordinator: Valerie Lonneman Date response received: REVIEWERS: Please specify how the attached plans conflict with your ADOPTED development regulations, including citations. Be specific in describing the types of changes you want made to the plans. When referencing codes, please identify the actual requirement and plan change needed. The Planning Division review does not supplant each department's ability to administer its own regulations and permits. However, project consistency at the Planning review stage is important to minimize significant later design changes. More than minimal design changes require further Planning Commission review, even if alteration is required to satisfy a City requirement. This further review is typically a minimum 60-day process. Requirements based on SEPA (e.g., not required by an adopted development regulation) MUST identify the impact being mitigated, the policy basis for requiring mitigation, and the method used to calculate the mitigation required. Calculations of project impacts and the mitigation required (e.g., water capacity, road level of service analyses, or turning analyses) may be required of the applicant. COMMENTS (Attach additional comment sheets and/or support materials as needed.) This application is for SEPA and Shoreline Substantial Development review. Eis--oeoi c`t se -PA �L,ec.�liSQ- (see_ f}rr ccL6_b. tlScrG CV04k Vt6ti) =a1-1�rF Jt. Plan check date: Comments i Update date: �/i c/i S prepared by: b w ` CITY OF TUKWILA PUBLIC WORKS DEPARTMENT REVIEW COMMENTS www.tukwila(@tukwilawa.gov Development Guidelines and Design and Construction Standards TO: PLANNING DIVISION — Valerie Lonneman, Assistant Planner /0I47/V1 FROM: PUBLIC WORKS DEPT. — David McPherson, Development Engineer (206) 431-2448 David. McPherson(a�TukwilaWA.gov DATE: July 10, 2015 SUBJECT: Green River Bank Erosion Repair at 14900 Interurban Ave. South TL no. 359700-0006 SEPA and Shoreline review comments SEPA — E15-0007 Public Works has the following SEPA review comments. The Environmental Checklist should be revised as follows: B. Environmental Elements 5. Animals c. Yes — This area is part of the Pacific Flyway. A primary corridor for migratory bird species. SHORELINE — L15-0032 Public Works has no Shoreline review comments. Page 1 of 1 f \ 0400 TO: City of Tukwila Department of Community Development File Number E15-0007 (SEPA) L15-0032 (Shoreline) LAND USE PERMIT ROUTING FORM Building Planning ❑I Public Works Fire Dept. Police Dept. Parks/Rec Project: Green River Bank Erosion Repair Address: 14900 Interurban Ave S., Tukwila, Washington Date transmitted: July 1, 2015 Response requested by: July 15, 2015 Staff coordinator: Valerie Lonneman Date response received: REVIEWERS: Please specify how the attached plans conflict with your ADOPTED development regulations, including citations. Be specific in describing the types of changes you want made to the plans. When referencing codes, please identify the actual requirement and plan change needed. The Planning Division review does not supplant each department's ability to administer its own regulations and permits. However, project consistency at the Planning review stage is important to minimize significant later design changes. More than minimal design changes require further Planning Commission review, even if alteration is required to satisfy a City requirement. This further review is typically a minimum 60-day process. Requirements based on SEPA (e.g., not required by an adopted development regulation) MUST identify the impact being mitigated, the policy basis for requiring mitigation, and the method used to calculate the mitigation required. Calculations of project impacts and the mitigation required (e.g., water capacity, road level of service analyses, or turning analyses) may be required of the applicant. COMMENTS (Attach additional comment sheets and/or support materials as needed.) This application is for SEPA and Shoreline Substantial Development review. Seer Ct-- C 15 -cc 7 6-1-Iz c c ke_cid-, s Plan check date: 7-/-5 comments prepared by: Update date: N at* of J aftwiea Department Of Community Development AFFIDAVIT OF DISTRIBUTION I, _Teri Svedahl , HEREBY DECLARE THAT: x Notice of Application Notice of Decision Notice of Public Hearing Notice of Public Meeting Determination of Non- Significance Mitigated Determination of Non - Significance Determination of Significance & Scoping Notice Short Subdivision Agenda Notice of Application for Shoreline Mgmt Permit Shoreline Mgmt Permit Board of Appeals Agenda Packet Board of Adjustment Agenda Packet Official Notice Notice of Action Other: Was mailed to each of the addresses listed/attached on this _ 16th day of _July 2015 Project Name: Green River Bank Repair Project Number: PL15-0027 Associated File Number (s): L15-0032, E15-0007 Mailing requested by: Valerie nneman Mailer's signature: 7)�viA.,,,,/C `-._ __ W:\USERS\TERI\TEMPLATES-FORMS\AFFIDAVIT OF DISTRIBUTION.DOC f `\ L. ! City of Tukwila Notice Of Application Green River Bank Repair Project Description: Install a subsurface drainage system and restore an eroded bank on the Green River at 14900 Inter- urban Ave. South. The project will receive Shoreline Substantial Development and SEPA (State Environmental Policy Act) deter- minations. File #'s: L15-0032, E15-0007 Property Owner: Kurt Schneider Applicant: Thomas Bannister, GeoEngineers, Inc. Project Planner: Valerie Lonneman 206-433-7140 or Valerie.Lonneman@TukwilaWA.gov Comments and Appeals: Your written comments on the pro- ject are requested and can be sent to Department of Community Development, 6300 Southcenter Blvd., Suite 100, Tukwila, WA 98188 or via email to Valerie.Lonneman@TukwilaWA.gov. Comments on SEPA must be received before or on July 30 by 5:00 pm; comments on the Shoreline review must be re- ceived before or on August 17 by 5:00 pm. To request a copy of any decision or information on your appeal rights, please call 206-433-7140. City of Tukwila Notice Of Application Green River Bank Repair to t5. 5,749th St , ) S 15 st,5t� Project Description: Install a subsurface drainage system and restore an eroded bank on the Green River at 14900 Inter- urban Ave. South. The project will receive Shoreline Substantial Development and SEPA (State Environmental Policy Act) deter- minations. File #'s: L15-0032, E15-0007 Property Owner: Kurt Schneider Applicant: Thomas Bannister, GeoEngineers, Inc. Project Planner: Valerie Lonneman 206-433-7140 or Valerie.Lonneman@TukwilaWA.gov Comments and Appeals: Your written comments on the pro- ject are requested and can be sent to Department of Community Development, 6300 Southcenter Blvd., Suite 100, Tukwila, WA 98188 or via email to Valerie.Lonneman@TukwilaWA.gov. Comments on SEPA must be received before or on July 30 by 5:00 pm; comments on the Shoreline review must be re- ceived before or on August 17 by 5:00 pm. To request a copy of any decision or information on your appeal rights, please call 206-433-7140. AGENCY US ARMY CORP OF ENGINEERS OFFICE OF ARCHAEOLOGY WSDOT NW REGION DEPT OF NATURAL RESOURCES WA FISHERIES & WILDLIFE DEPT OF ECOLOGY WA DEPT OF ECOLOGY WA STATE ATTORNEY GENERAL KC PARKS & RECREATION KC ASSESSOR'S OFFICE KC DEV & ENVIRON SERVICES KC METRO TRANSIT/SEPA OFFICIAL KC DEPARTMENT OF NAT'L RESOURCES FOSTER LIBRARY WESTFIELD MALL LIBRARY SEATTLE PUBLIC SCHOOLS SEATTLE CITY LIGHT SEATTLE PLANNING & DEVELOPMENT SEATTLE PUBLIC UTILITIES WASTE MANAGEMENT CITY OF SEATTLE MUCKLESHOOT Cultural Resources Program MUCKLESHOOT Fisheries Program MUCKLESHOOT Wildlife Program DUWAMISH INDIAN TRIBE PUGET SOUND CLEAN AIR AGENCY SOUND TRANSIT/SEPA OFFICIAL DUWAMISH RIVER CLEAN UP COALITION WA ENVIRONMENTAL COUNCIL PEOPLE FOR PUGET SOUND DEPT DEVELOPMENT SERVICES NW REGIONAL OFFICE SEPA REVIEW ECOLOGY DEPARTMENT ACCOUNTING DIVISION SEPA INFO CENTER ENVIRONMENTAL PLANNING SEPA Review / Joe Wolf ENVIRONMENT & SAFETY DIV WATER DEPARTMENT JALAINE MADURA, SEPA SEPA CONTROL PLANNING & DEVEL Laura Murphy Karen Walter Mike Middleton SEPA REVIEW UNION STATION ADDRESS 4735 E MARGINAL WY S PO BOX 48343 PO BOX 330310, MS 240 PO 47015 16018 MILL CREEK BLVD 3190 160th AVE SE PO BOX 47703 PO BOX 40117 201 S JACKSON ST., STE 700 S00 4th AVE, RM# 709A 35030 SE Douglas Street, Ste 210 201 S JACKSON ST., MS KSC-TR-0431 201S JACKSON ST., STE 600 4060 S 144th STREET 1386 SOUTHCENTER MALL PO BOX 34165 MS 22-332 PO BOX 34023 PO BOX 34019 PO BOX 34018 8111-1st AVE S PO BOX 34019 39015 172nd AVE SE 39015 172nd AVE SE 39015 172nd AVE SE 4705 W MARGINAL WAY SW 1904 3rd AVENUE, STE 105 401 S JACKSON STREET 210 S Hudson Street, Ste 332 1402 THIRD AVE, STE# 1400 1402 - 3rd Ave, Ste 1400 CITY ST ZIP SEATTLE WA 98124 OLYMPIA WA 98504 SEATTLE WA 98133 OLYMPIA WA 98504 MILL CREEK WA 98012 BELLEVUE WA 98008 OLYMPIA WA 98504 LACEY WA 98504 SEATTLE WA 98104 SEATTLE WA 98104 SNOQUALMIE WA 98065 SEATTLE WA 98104 SEATTLE WA 98104 TUKWILA WA 98168 TUKWILA WA 98188 SEATTLE WA 98124 SEATTLE WA 98124 SEATTLE WA 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COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER ADDRESS 100 ANDOVER PARK W # 150 10607 DES MOINES MEMORIAL DR 10955 SE 169TH PL 1125 E 60TH ST 11310 148TH AVE SE 11627 SE 192ND ST 119 S 60TH 11903 SE 71ST PL 1214 TAYLOR AVE N # 301 12811 12TH AVE S 12909 13TH PL NE 12918 1ST AVE SW # B 1299 UNION RD # C109 1333 32ND PL NE 13404 173RD ST E 13729 SE 256TH PL 1425 SANFORD DR 14675 INTERURBAN AVE S # 303 14800 INTERURBAN AVE S 14800 STARFIRE WAY 14805 INTERURBAN AVE S 14851 INTERURBAN AVE S 14891 INTERURBAN AVE S 14893 INTERURBAN AVE S 14895 INTERURBAN AVE S 14900 INTERURBAN AVE S 14901 INTERURBAN AVE S 14903 INTERURBAN AVE S 14925 INTERURBAN AVE S 14928 18TH SW 14973 INTERURBAN AVE S 15100 65TH AVE S 15130 65TH AVE S 1525 4TH AVE STE 400 15410 SE 272ND ST # 39 1546 65TH AVE S # 503 15510 6TH AVE SW # 1 1607 DES MOINES MEMORIAL DR 16215 9TH AVE SW 16360 SIMONDS RD NE 1800 9TH AVE # 11TH FL AMAZON M 18107 NORMANDY TER SW 1824 MAPLE LN # K59 19752 40TH AVE S 20221 90TH PL S 20410 33RD AVE NE 21250 SE 42ND PL CITY ST TUKWILA WA SEATTLE WA RENTON WA TACOMA WA RENTON WA KENT WA TACOMA WA NEWCASTLE WA SEATTLE WA BURIEN WA LAKE STEVENS WA BURIEN WA KIHEI HI AUBURN WA PUYALLUP WA KENT WA FORT COLLINS CO TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA TUKWILA WA BURIEN WA TUKWILA WA TUKWILA WA TUKWILA WA SEATTLE WA KENT WA TUKWILA WA BURIEN WA SEATTLE WA BURIEN WA KENMORE WA -RM SEATTLE WA NORMANDY PARK WA KENT WA SEATAC WA KENT WA SEATTLE WA ISSAQUAH WA ZIP 98188 98168 98055 98404 98168 98031 98404 98056 98109 98168 98258 98146 96753 98002 98374 98042 80526 98168 98188 98188 98188 98188 98188 98188 98188 98188 98188 98188 98188 98166 98188 98188 98188 98101 98042 98188 98166 98168 98166 98028 98101 98166 98030 98188 98031 98155 98029 r 1 COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER COMMUNITY MEMBER 2131 LOWER PEOH POINT RD 21403 96TH AVE S 22302 97TH AVE W 23628 SE 127TH CT 23987 58TH CT S # D2 24115 118TH PL SE 2430 169TH PL SE 2450 38TH ST 2702 CEDAR AVE S 2717 76TH AVE SE # 103 27758 214TH AVE SE 30028 45TH AVE S 3046 ALKI AVE SW # 103 3325 59TH AVE SW 33638 38TH AVE S 3794 EMILIA DR 4368 CLAIREMONT MESA BLVD # 60 4509 160TH PL SE 4556 12TH AVE S 4720 MILL POND DR SE # 507 4801 FREDERICA ST 486 SUMMIT AVE 5008 S ROSE ST 5703 S LEO ST 5732 S RYAN ST 6230 S 149TH PL 625 ILWACO AVE NE 6250 S 151ST ST 644 SHREWSBURY COMMONS AVE # 6750 FRANCIS LOOP SE 705 E DECATUR ST 7320 E GREENLAKE DR N # 202 7517 GREENWOOD AVE N 7914 S 120TH ST 8017 141ST AVE SE 8616 42ND AVE S 8624 RENTON AVE S 900 SW 16TH ST STE 200 901 POWELL AVE SW STE 101 931 14TH ST STE 103 950 N 72ND ST # 100 9748 57TH AVE S PO BOX 1463 PO BOX 16597 PO BOX 251006 PO BOX 3095 PO BOX 88665 CLE ELUM WA KENT WA EDMONDS WA KENT WA KENT WA KENT WA BELLEVUE WA BELLINGHAM WA RENTON WA MERCER ISLAND WA MAPLE VALLEY WA AUBURN WA SEATTLE WA SEATTLE WA FEDERAL, WAY WA PORT ORANGE FL SAN DIEGO CA BELLEVUE WA SEATTLE WA AUBURN WA OWENSOBORO KY MAPLEWOOD NJ SEATTLE WA SEATTLE WA SEATTLE WA TUKWILA WA RENTON WA TUKWILA WA 192 SHREWSBURY PA AUBURN WA TULSA OK SEATTLE WA SEATTLE WA SEATTLE WA NEWCASTLE WA SEATTLE WA SEATTLE WA RENTON WA RENTON WA DENVER CO SEATTLE WA SEATTLE WA RENTON WA SEATTLE WA GLENDALE CA RENTON WA TUKWILA WA 98922 98031 98020 98031 98032 98030 98008 98229 98055 98040 98038 98001 98116 98116 98001 32127 92117 98006 98108 98092 42301 7040 98118 98178 98178 98168 98059 98188 17361 98092 74011 98115 98103 98178 98059 98118 98118 98057 98057 80202 98103 98118 98057 98116 91225 98056 98138 NAME ADDRESS CITY ST ZIP TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 1 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 10 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 12 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 13 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 14 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 15 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 16 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 17 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 18 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 2 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 3 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 4 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 5 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 6 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 7 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 8 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14893 INTERURBAN AVE Apt 9 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 37 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 38 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 39 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 40 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 41 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 42 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 43 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 44 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 45 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 46 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 47 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 48 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 49 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 50 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 51 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 52 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 53 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14895 INTERURBAN AVE Apt 54 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 55 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 56 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 57 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 58 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 60 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 61 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 62 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 63 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 64 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 65 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 66 TUKWILA WA 98168 / 1 f TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 67 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 68 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 69 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 70 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 71 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14897 INTERURBAN AVE Apt 72 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 73 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 74 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 75 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 76 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 77 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 78 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 79 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 80 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 81 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 82 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 83 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 84 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 85 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 86 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 87 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 88 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 89 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14899 INTERURBAN AVE Apt 90 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 100 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 101 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 102 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 103 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 104 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 105 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 106 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 107 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 108 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 91 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 92 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 93 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 94 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 95 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 96 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 97 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 98 TUKWILA WA 98168 TUKWILA COMMUNITY MEMBER 14901 INTERURBAN AVE Apt 99 TUKWILA WA 98168 / NAME ADD STREET unit # CITY ST ZIP TUKWILA COMMUNITY MEMBER 15138 65TH AVE S # 101 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15138 65TH AVE S # 102 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15138 65TH AVE S # 103 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15138 65TH AVE S # 104 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15138 65TH AVE S # 105 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 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WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 903 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 904 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 905 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 906 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 907 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 908 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 909 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 910 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 911 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15154 65TH AVE S # 912 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1001 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1002 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1003 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1004 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1005 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1006 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1007 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1008 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1009 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1010 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1011 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1012 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1013 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1014 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1015 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1016 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1017 TUKWILA WA 98188 TUKWILA COMMUNITY MEMBER 15156 65TH AVE S # 1018 TUKWILA WA 98188 1 / 1 Teri Svedahl From: Teri Svedahl Sent: Thursday, July 16, 2015 7:35 AM To: 'sepaunit@ecy.wa.gov' Cc: Valerie Lonneman Subject: Green River Bank Repair, Tukwila Attachments: PL15-0027 Half Sheet Notice.pub Attached is Notice of Application for a Tukwila project to restore an eroded bank on the Green River. Please contact Valerie Lonneman with any questions. Valerie.Lonneman@TukwilaWA.Rov Teri Svedahl !Administrative Support Technician City of Tukwila I Planning Department 6300 Southcenter Boulevard - Ste 100 I Tukwila WA 98188 Teri.Svedahl n@Tukwila WA.gov The City of opportunity, the community of choice. Please be advised: This email is subject to public disclosure CO'51) lc los oP�e ''` O° June 18, 2015 LD Schneider and Associates 3200 North Central Avenue, Suite 1470 Phoenix, Arizona 85012 Attention: Kurt Schneider Subject: Analysis and Design Report Green River Bank Repair 14900 Interurban Avenue South Tukwila, Washington GeoEngineers File No. 21493-001-01 INTRODUCTION GEOENGINEER S....0 Plaza 600 Building 600 Stewart Street, Suite 1700 Seattle, Washington 98101 206.728.2674 GeoEngineers, Inc. (GeoEngineers) is pleased to present an analysis of site conditions and a design to repair an eroding bank along the Green River adjacent to the property at 14900 Interurban Avenue South in Tukwila, Washington. The location of the site is mapped on Sheet C-1 in Appendix A. The purpose of this report is to support an application to the City of Tukwila for a Shoreline Substantial Development Permit and to the Washington State Department of Fish and Wildlife (WDFW) for a Hydraulic Project Approval (HPA). We prepared this report to comply with the submittal requirements of Tukwila Municipal Code (TMC) 18.44. GeoEngineers assessed the causes of bank failure and developed multiple design alternatives for consideration by the owner. We also evaluated the permitting considerations of each option. As part of our preliminary work, we completed a site assessment and developed a design to address the mechanisms of bank failure. This report details our methods and findings regarding site conditions, mechanism of failure and presents permit level design drawings to mitigate for bank failure and restore the bank to a functional condition. SITE DESCRIPTION AND CONDITIONS The 3.6-acre property (Parcel #3597000006) is located on the left (west) bank of the Green River. An approximately 57,000 square -foot, 2-story office building and parking areas are located on the parcel. The parcel is generally flat and the river is not leveed. The Green River is not tidally influenced at this location and overbank bank flooding is extremely rare, particularly on the left bank of the river. The area of the parcel that is within 200 linear feet of the Ordinary High Water Mark (OHWM) of the Green River is regulated under the City of Tukwila's Shoreline Master Program. The Shoreline designation for the site is Urban Conservancy and the River has a buffer of 100 feet measured from 01-IWM. The site is also designated as a Fish and Wildlife Habitat Conservation Area per TMC 18.44.090 H. LD Schneider and Associates June , 2015 Page 2 A GeoEngineers biologist made a preliminary site visit on May 13, 2014. In general, the riverbank on the property is vegetated with noxious and invasive Himalayan blackberry. Because of the infestation of Himalayan blackberry and lack of trees, habitat conditions along the riverbank are degraded. GeoEngineers observed evidence of a recent slough of the bank located approximately 100 feet southeast of the commercial building on the property. The recent sloughing resulted in an approximately 10-foot high near vertical escarpment that damaged an existing asphalt trail at the top of the bank. The trail is separated from the parking lot by a landscaping island consisting of grass and a row of seven mature sycamore trees. The biologist also observed water weeping from the bank at the toe of the escarpment. The biologist did not observe environmentally sensitive areas, such as wetlands, during the site reconnaissance. 0n August 12, 2014, a GeoEngineers geotechnical engineer, river hydrologist, and biologist evaluated slope stability, habitat, and flow conditions at the site. During this site visit, the geotechnical engineer noted that the soil exposed in the riverbank consisted of fine to medium silty sand and silt. This material is typical of alluvium in the Green River valley. Bedrock was observed in the riverbanks upstream (south) of the property. Bedrock is also known to be present (State of Washington Department of Natural Resources [DNR] Geology Maps) on the hillside t.o the west of the site. DNR maps the local geologic unit as the Puget Group (Tp). The Puget Group consists of sandstone, siltstone, claystone, and coal which is white and very fine grained to gritty. The Tiger Mountain Formation, which consists of light-colored, medium -grained sandstone with siltstone, minor pebble conglomerate, and coal beds, is mapped in isolated outcrops in the river valley. The Renton Formation (Tpr), which is a fine- to coarse -grained sandstone with interbedded siltstone, claystone, and coal, is mapped on the hillside to the west of the site. Alluvial deposits (Qal) are mapped immediately adjacent to the site as comprising the river bed and riverbanks. Alluvium is described as a mix of moderately to poorly sorted granular soils deposited by the river. We completed two subsurface geologic explorations at the top of the recently sloughed area where the trail has become undermined and approximately halfway between this point and the corner of the building. These explorations were performed with a track -mounted drill rig and advanced to a depth of 36.5 feet (at the top of the slough) and 51.5 feet (nearer to the building). Summary logs of our explorations are included as Appendix A. The subsurface conditions at the site is consistent with a glacial channel that was carved into siltstone and sandstone and then partially filled with more recent allluvium from the Green River. We observed the alluvium to consist of very loose to medium dense silty sand to a depth of approximately 35 feet. We observed the silty sand material to overlie a white to light gray sandstone with fine inclusions of coal layers. We interpret this sandstone to be a part of the Tiger Mountain Formation of the Puget Group. The two borings were terminated within the sandstone. We observed groundwater in the borings at a depth of approximately 12-14 feet below ground surface, which is consistent with earlier observations of groundwater seeping out from the toe of the sloughed surface. GEOENGINEERS. File No. 21493-001-01 f\ LD Schneider and Associates June 1, 2015 Page 3 MECHANISM OF BANK SLOUGHING Based on our observations at the site and experience in the Green River valley, it is our opinion that the bank sloughing is most likely due to a drawdown failure. This type of failure occurs when high groundwater levels and high river levels saturate the riverbank soil and then the river levels drops or "draws down" faster than the water can drain from the riverbank soil. This creates an imbalance of water pressure. The water pressure pushing the bank from within the soil is no longer balanced by the water pressure from the river and the riverbank is pushed into the river. In our experience, this is the most common riverbank failure mechanism on the lower Green River. Toe erosion is also a failure mechanism that is common on the Green River and often found in conjunction with drawdown failures. Toe erosion will weaken a riverbank but the ultimate failure is triggered by drawdown. At this site, the presence of shallow bedrock makes toe erosion less likely to be a significant contribution to the failure of the riverbank. In addition to site observations, bathymetric data of the channel bottom was obtained from King County. Cross sections of the channel bottom in the vicinity of the site do not show the large scour holes typically evident in areas where toe erosion is a major contributor to slope instabilities. We do not believe toe erosion to be a contributing factor in the of bank sloughing at the site. PROJECT DESIGN We developed a permit -level design to mitigate for the bank sloughing and also to address potential future drawdown failures. Permit level design drawings are included as Attachment B. The design objective was to develop a plan appropriate for the site geology and geometry using techniques and materials most likely to be approved by regulatory agencies and offer long term protection. During preliminary design, we considered bio-engineered and hard engineering approaches. The identified design options are located landward of the OHWM for permitting efficiency. Additionally, we believe work waterward of OHWM is unnecessary because the mechanism of failure is not a result of toe erosion. As such, the project will avoid impacts to aquatic habitat at the site. Riverbank Drainage The project consists of installing a subsurface gravity drainage system to transport water away from the failure plane and rebuilding the riverbank using a combination of structural fill and native soil. The subsurface drainage system consists of a perforated 4-inch schedule 40 polyvinyl chloride (PVC) pipe that will capture subsurface water along the 165-foot length of the bank repair. Solid 4-inch PVC finger drains set at approximately 20-foot intervals will convey the water from the perforated pipe to outfalls located landward of OHWM. Small rock will be installed at the outfalls to protect against erosion. This rock is designed to withstand flows from the pipe and sheer stress of river flows under anticipated conditions. This design will reduce the water pressure upgradient of the riverbank and thereby reduce the potential for future drawdown failures. The project is designed to address the primary cause of bank failure (drawdown) and does not include design elements to protect against toe erosion or scour. We anticipate that a qualified contractor will install the drainage system and restore the bank using a medium-sized track mounted excavator and other support equipment. The project will be completed during WDFW's allowable in water work window, or approximately August 1- August 31. Construction is estimated GEOENGINEERS. File No. 21493-001-01 LD Schneider and Associates June 2015 Page 4 to take approximately 2 weeks. Because the project is located in the 100-foot buffer of the Green River, TMC 18.44.090 E(4) requires the owner, the specialist of record (GeoEngineers), the contractor and representatives from the City of Tukwila to attend a preconstruction meeting at the site. Per TMC 18.44.090 E(5), GeoEngineers will be retained to monitor construction. We estimate that approximately 420 cubic yards (yd3) of material will be cut and filled to complete the project. Of this 420 cubic yards of material, approximately 160 cubic yards will be native material that will remain on site and will be incorporated back into the riverbank. It will be necessary to import additional material to achieve the design elevations and grades. This material and the estimated quantities are listed below. Anticipated Material Schedule Approximately 420 yd3 of cut and fill: • Approximately 160 yd3 of native material to remain on site. ■ Approximately 160 yd3 of imported riverbank fill. ■ Approximately 96 yd3 of imported topsoil. • Approximately 3 yd3 of 1-inch drain rock. • Approximately 1 yd3 of imported outfall protection. Stability Analysis of Design We analyzed the proposed slope repair using the computer program SLOPE/W (GEO-SLOPE International, Ltd., 2012). The SLOPE/W program evaluates the stability of numerous trial shear surfaces using a vertical slice limit -equilibrium method (Morgenstern -Price). This method compares the ratio of forces driving slope movement to the forces resisting slope movement for each trail shear surface, and presents the ratio as the factor of safety. The program then sorts the trail shear surfaces and identifies the surface with the lowest factor of safety, or the "critical" shear surface. We first analyzed the slope in what was likely its configuration just prior to the slough occurring. Our analysis was based on the subsurface data collected in our explorations and on groundwater conditions consistent with a drawdown condition. For this condition we calculate that the factor of safety is less than 1.0. This indicates that the forces driving slope movement exceed the forces resisting slope movement and that the slope would fail. Additionally, the calculated critical shear surface is similar to the observed shear surface of the slough. This result further corroborates our opinion that the bank slough was triggered by drawdown. We then analyzed the slope with the proposed repair in place. In this case we calculate that the factor of safety against a drawdown type failure is 1.3, indicating that the forces available for resisting slope movement exceed the forces driving slope movement by about 30 percent. As a point of reference, the United States Army Corps of Engineers (USACE) recommends a calculated factor of safety greater than about 1.0 or 1.1 against drawdown failures. GEOENGINEERS File No. 21493-001-01 \ LD Schneider and Associates June 18 2015 Page 5 Site Restoration Following installation of the riverbank drainage, the disturbed areas will be restored and enhanced. The design goal for the project is to reconstruct the bank at an approximate pre -slough slope angle, or 2.5:1 slope. However, the slope angle of the bank reconstruction will be established to fit within the site constraints, including avoiding damage to the large sycamore trees atop the bank, limiting disturbance to the root zone and transitioning into the native banks adjacent to the repair. To accommodate this slope angle, the existing asphalt trail at the top of the bank may need to be realigned. The alignment of the trail will be established following restoration of the bank. Due to the anticipated sheer force during high flow events in the river, we anticipate that the reconstructed bank will require additional erosion protection. 0ur design includes a biodegradable erosion control fabric designed to withstand sheer stresses under normal flow conditions. The erosion control fabric will also stabilize the bank slope from raveling during heavy rain events. Because the project will be completed landward of OHWM, we do not anticipate temporary or permanent impacts to the aquatic habitat of the Green River. Temporary impacts will be limited to the blackberry and English ivy infested bank above OHWM. No trees will be removed as part of the project. The seven mature sycamores along the top of bank will be protected during construction per the requirements of the Shoreline Substantial Development permit. Because of the proximity of these mature trees to the work area it is not practical to protect the trees in the manner required by TMC 18.44.080 B (10). GeoEngineers recommends that the contractor establish tree protections at the maximum practical distance from the trunks of the sycamore trees to complete the project. The work area is currently infested with Himalayan blackberry which will be removed during construction. The project design includes aggressive revegetation to reestablish root strength and help stabilize the bank. Native plant species will be densely installed in the areas disturbed by the project. Below is a list of recommended plants to be installed at the site to reestablish root structure and appropriate riparian habitat. Estimated Quantity 5 9 5 5 25 25 25 25 25 Common Name Black cottonwood Western red cedar Big leaf maple Pacific dogwood Vine maple 0ceanspray Snowberry Western serviceberry Red osier dogwood Scientific Name Populus balsamifera Thuja plicata Acer macrophyllum Corpus nutalli Acer circinatum Holodiscus discolor Symphoricarpos albus Amelanchier alnifolia Corpus sericea Size Spacing 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 6 - 8 feet in height 24—inch in height 24—inch in height 24—inch in height 24—inch in height 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 10 feet o.c. 5 feet o.c 5 feet o.c 5 feet o.c 5 feet o.c File No. 21493-001-01 GEOENGINEERSI17 LD Schneider and Associates June .. ,2015 Page 6 We developed this native plant palette based on our experience with riparian restoration and with guidance from WDFW (Cramer, 2012). We increase the density of the installed trees to 10 feet on -center at the request of WDFW (2015). Installed deciduous trees will be 2-inch caliper, conifer will be 6-8 foot height and shrubs will be 24-inch height in compliance with TMC 18.44.080 C(1)(j). Trees will be planted on 10-foot spacing per WDFW's request and shrubs will be planted on 5-foot spacing per TMC 18.44.080 C(2)(d). To enhance aquatic habitat, the GeoEngineers biologist will provide guidance to the contractor in installing the plants in locations that promote shade and overhanging vegetation near OHWM while maintaining the view corridors of the existing riverfront trail. Large trees will be installed outside the drip line of the existing sycamore trees. The planting plan also accounts for the seasonally fluctuating river levels and variable hydrology up the slope of the riverbank. Because of the typical hot and dry conditions during WDFW's allowable work window, we recommend that the revegetation of the riverbank be delayed until late fall. Planting in late summer will likely result in plant failure and poor revegetation. The erosion control fabric installed on the riverbank will stabilize the bank in the interim between repair of the bank and site revegetation. To avoid and minimize water quality impacts during construction, temporary erosion and sediment controls will be installed prior to site work. A silt fence will be installed on the downslope construction limits, near OHWM, as the primary water quality protection. Contingency water quality protections include additional silt fence, silt curtains and straw wattles. We estimate the cost to construct the bank repair to be approximately $65,000. 0ur Project Value documentation is included as Appendix C. Maintenance and Monitoring We anticipate that the riverbank drainage system will require minimal maintenance. Maintenance will include occasional flushing of the system via backwashing from the outfalls. The frequency of this maintenance will be determined on an as needed basis. The restored vegetation on the bank will be managed by the on -site property management staff. We anticipate that the riverbank will be maintained as a part of their routine maintenance regimen. Maintenance will include physical removal of noxious and invasive species that may be detrimental to the restored riparian habitat along the riverbank. These noxious and invasive species include but are not limited to: • Knotweeds (Polygonum spp.) • Butterfly bush (Buddleja spp.) • Himalayan blackberry (Rubus armeniacus) • English ivy (Hedera helix) • Scotch broom (Cytisus scoparius) Use of chemical herbicides to control these species is considered unnecessary and is not recommended. We recommend that the installed plants be watered during the dry season for a minimum of three years following plant installation. This watering should occur during the late summer and the frequency shall be determined based on weather conditions and plant performance. GEOENGINEERZ File No. 21493-001-01 LD Schneider and Associates l � June 18, 2015 Page 7 Beneficial volunteer plants, such as other native species, will be encouraged at the site. Installed plants that do not survive will be replaced as required by the authorizations from the City of Tukwila and WDFW. We anticipate that a provision of the permit issued by WDFW will require 80 percent survival of installed plants for three years following construction of the project. The City of Tukwila will likely require monitoring of the site for a period of five years following plant installation. To monitor performance of the restored vegetation and to comply with project permits, a qualified biologist will annually monitor the site for a period of five years following construction of the project. To track vegetation performance at the site through the monitoring period, we recommend that the monitoring biologist establish a transect along the bank. Using the line intercept method, the biologist will inventory the number and species of native plants observed within 1 foot of either side of the transect shortly following installation of the plants. The location, orientation and length of this transect will be determined in the field by the biologist. The endpoints of the transect will be marked in the field. The biologist will return to the site on an annual basis to complete the survival inventory at the location of the transect. The biologist will determine annual survival rates which will be used to gauge compliance with WDFW's permit. Our experience has shown that calculating survival rates is problematic because of the inherent difficulty of identifying individual plants as the site matures. We recommend that the biologist also measure the areal cover of beneficial vegetation along the length of the transect. It is our opinion that measuring the areal cover of native plants is a better indicator of site performance, is more repeatable and results in less variability amongst site investigators during the monitoring period. Native volunteer plants will be included in the plant inventory and areal cover measurements for the remainder of the monitoring period. The biologist will complete monitoring events on an annual basis for five years following plant installation. The findings of each monitoring event will be documented and the owner will submit annual reports to the City of Tukwila and WDFW. NO NET LOSS ANALYSIS AND MITIGATION SEQUENCING Consistent with the City of Tukwila's Shoreline Master Program (SMP), this project will result in no net loss of shoreline ecological function. The project will result in approximately 5,000 square feet of temporary impacts to the shoreline. These impacts are necessary to eliminate the inherent public safety issue posed by the slope failure and to maintain safe, public access to the shoreline on the property. To rectify these unavoidable impacts, the project follows the mitigation sequencing steps identified in TMC 18.44.070 H(3). Because the project is located landward of OHWM, it avoid impacts to the aquatic environment of the Green River. The riparian habitat that will be impacted by the project is heavily degraded and infested with noxious and invasive plants species. The project proposes to restore and enhance the riparian habitat by removing invasive species and installing native trees and shrubs. The owner is committed to maintaining and monitoring the impacted area to ensure the success of the restoration. As a result of these mitigation steps, the project results in no net loss of shoreline ecological function. We estimate that approximately 200 cubic yards of bank material sloughed into the river during a recent drawdown failure. Much of this material has subsequently been eroded and carried downstream by the river. The drawdown failure resulted a 9-foot high vertical escarpment that damaged the existing public access trail. The escarpment poses a safety risk which has resulted in the closure of the trail. To eliminate this safety hazard, the project will add approximately 160 cubic yards of fill material. This fill material is intended to replace a portion of the bank lost as a result of drawdown failure. We consider this amount of fill to be minor and will have no measureable impact to the hydrology, habitat or other shoreline function. EGEOENGINEERS.....0 File No. 21493-001-01 LD Schneider and Associates June �. , 2015 Page 8 REFERENCES Cramer, Michelle L. (managing editor). 2012. Stream Habitat Restoration Guidelines. Co -published by the Washington Departments of Fish and Wildlife, Natural Resources, Transportation and Ecology, Washington State Recreation and Conservation Office, Puget Sound Partnership, and the U.S. Fish and Wildlife Service. Olympia, Washington. WDFW. 2015. Personal Communication between Larry Fisher (WDFW) and Thomas Bannister (GeoEngineers) on June 9, 2015. LIMITATIONS We have prepared this report for LD Schneider and Associates for failing bank along the Green River adjacent to the property at 14900 Interurban Avenue South in Tukwila, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the fields of geotechnical engineering, hydrology, and restoration design engineering in this area at the time this report was prepared. The conclusions, recommendations and opinions presented in this report are based on our professional knowledge, judgment and experience. No warranty, express or implied, applies to our services and this report. Any electronic form, facsimile or hard copy of the original document (email, text, table and/or figure), if provided, and any attachments should be considered a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Sincerely, GeoEngineers, Inc. Thomas A Bannister Lyle J. Stone, PE, GE Biologist Senior Geotechnical Engineer Jonathan M. Ambrose Associate Hydrologist TAB:US:JMA:Ieh Attachments: Appendix A. Geologic Boring Logs Appendix B. Permit Level Design Drawings Appendix C. Project Value Documentation One copy submitted electronically Disclaimer. Any electronic form, facsimile or hard copy of the original document (email, text, table, and/orfigure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and wal serve as the official document of record. GEOENGINEERS_ File No. 21493-001-01 APPENDIX A Geologic Boring Logs SOIL CLASSIFICATION CHART Al JITIONAL MATERIAL SYMBOLS MAJOR DIVISIONSSYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER COARSE GRAINED SOILS MORE THAN 50% RETAINED ON NO. 200 SIEVE GRAVEL AND GRAVELLY SOILS MORE THAN 50%OF COARSE FRACTION RETAINED ON NO.4 SIEVE CLEAN GRAVELS (LITHE OR NO FINES) OU U C 0 o o ) (",� GW WELL -GRADED GRAVELS, GRAVEL -SAND MIXTURES o 0 0 0 0 c D 0 o GP POORLY -GRADED GRAVELS, GRAVEL - SAND MIXTURES GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINES) GM SILTY GRAVELS, GRAVEL -SAND SILT MIXTURES 111/ o z GC CLAYEY CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES SAND AND SANDY SOILS MORE THAN 50% OF COARSE FRACTION PASSING NO. 4 SIEVE CLEAN SANDS (LITRE OR NO FINES) ° sw GRAVELLLY SANDS DS, SP POORLY -GRADED SANDS, GRAVELLY SAND SANDS WITH FINES (PRECIABANT FINES)MIXTURES SM SILTY SANDS, SAND - SILT MIXTURES SC CLAYEY SANDS, SAND -OF FINE GRAINED SOILS MORE THAN 50% PASSING NO. 200 SIEVE SILTSMEDIUM AND CLAYS LIOUID LIMICL LESS THAN 50 f ML INORGANIC SILTS, ROCK FLOUR, CLAYEY SILTS WITH SLIGHT PLASTICITY INORGANICCLAYSOFLOWTO PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY SILTS AND CLAYS LN]UID LIMIT GREATER THAN50 ) J MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS SILTY SOILS / CH INORGANIC CLAYS OF HIGH PLASTICITY I I ~/\ OH ORGANIC CLAYS AND SILTS OF MEDIUM TO HIGH PLASTICITY HIGHLY ORGANIC SOILS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS = = = PT NOTE: Multiple symbols are used to indicate borderline or dual soil classifications LI ■ 11 x Sampler Symbol Descriptions 2.4-inch I.D. split barrel Standard Penetration Test (SPT) Shelby tube Piston Direct -Push Bulk or grab Continuous Coring Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (or distance noted). See exploration log for hammer weight and drop. A "P" indicates sampler pushed using the weight of the drill rig. SYMBOLS TYPICAL DESCRIPTIONS GRAPH LETTER AC Asphalt Concrete CC Cement Concrete CR Crushed Rock/ Quarry Spalls TS Topsoil/ Forest Duff/Sod °/oF AL CA CP CS DS HA MC MD OC PM PI PP PPM SA TX UC VS NS SS MS HS NT Groundwater Contact Measured groundwater level in exploration, well, or piezometer Measured free product in well or piezometer Graphic Log Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Material Description Contact Distinct contact between soil strata or geologic units Approximate location of soil strata change within a geologic soil unit Laboratory / Field Tests Percent fines Atterberg limits Chemical analysis Laboratory compaction test Consolidation test Direct shear Hydrometer analysis Moisture content Moisture content and dry density Organic content Permeability or hydraulic conductivity Plasticity index Pocket penetrometer Parts per million Sieve analysis Triaxial compression Unconfined compression Vane shear Sheen Classification No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen Not Tested NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to be representative of subsurface conditions at other locations or times. i KEY TO EXPLORATION LOGS GEOENGINEERS!/� FIGURE A-1 f � / Start End Total ""-'51.5 Depth (ft) Logged BAW/SST Checked By LJS Driller Holocene Drilliny'Inc. Drilling Hollow Stem Auger Method Drilled 4/23/2015 4/23/2015 Surface Elevation (ft) 28 Vertical Datum NAVD88 Hammer Auto Hammer Data 140 (Ibs) / 30 (in) Drop Drilling Diedrich D50 Truck Rig Equipment Easting (X) Northing (Y) System Datum Groundwater Depth to Date Measured Water (ft) Elevation (ft) Notes: See Remarks II 20 ds Elevation (feet) o Depth (feet) l rI FIELD DATA Graphic Log Croup lass Classification Moisture Content (%) Interval Recovered (in) o 3 p m Collected Sample Sample Name Testing Water Level MATERIAL DESCRIPTION L- y.2 s0 u.0 REMARKS J 2 12 3 4 2A ML Brown silt with sand, occasional organic matter - (twigs, duff) (soft, moist) J 118 4 2B %F ML _ Brown silt with sand (medium stiff, moist) - (alluvium) 21 56 8 3 aA MC / ML Brown silt, trace sand (soft, moist) (alluvium) 48 - 10--] -,:0 15 - _NC) 18 I 18 14 1 18 5 9 10 7 48 SA 6 BA SM Gray silty sand (very loose, moist) (alluvium) Grades to loose, wet — _ - - 33 36 Groundwater observed at 14 feet at time of drilling - - 20114 h - 3 BB 2 ML _ Gray silt, trace sand (medium stiff, moist) _ (alluvium) 57 98 25 -J - 301 - —y - 351 Note: See 16 12 18 Figure 22 21 25 A-1 for 10 11 12 explanation of symbols. / SP-SM _ Gray fine to coarse sand with silt (medium dense, — wet) (alluvium) _ Log of Boring B-1 G EO E N G I N E E RSA,/, Project: Project Location: Project Number: Green River Bank Design and Permitting Tukwila, Washington 21493-001-01 Figure A-2 Sheet 1 of 2 :GEOENGINEERS8.GDT/GEIB GEOTECH STANDARD 1- E Seattle: Dete:6/17/15 Path:W:\SEATTLE\PROJECTS \21\214 Elevation (feet) 0 40� 12 Z 1 c Recovered (in) FIELD DATA 8 N m Collected Sample 5) E z Water Level MATERIAL DESCRIPTION C 2 c CI u. 0 REMARKS 45 A 18 50, 18 22 50 73 13A 13B 14 15 SAND STONE - Sandstone: white; visually fresh; fine grained (Puget Group Tiger Mountain formation) Note: See Figure A-1 for explanation of symbols. Log of Boring B-1 (continued) GEOENGINEERS Project: Green River Bank Design and Permitting Project Location: Tukwila, Washington Project Number: 21493-001-01 Figure A-2 Sheet 2 of 2 / Start End 4/23/2015 Total � 36.5 Depth (ft) Logged BAW/SST Checked By LJS �' Driller Holocene DrillilfiLj Inc. Drilling g Method Hollow Stem Auger Drilled 4/23/2015 Surface Elevation (ft) Vertical Datum 28 NAVD88 Hammer Data 140 (Ibs) / 30 (in) Drop Drilling Diedrich D50 Truck Rig Equipment Easting (X) Northing (Y) System Datum Groundwater Depth to Date Measured Water (ft) Elevation (ft) Notes: • See Remarks o 1 1 i 1 1 i 1 1 1 i I i i 1 1 1 1 1 1 i 1 1 1 1 i I 1 i 1 i 1 Is Is'o vs ?0 s Elevation (feet) Ul o N o cn o o o Depth (feet) FIELD DATA Graphic Log Group Classification Moisture Content (%) Interval Recovered (in) 2 O Fai. Collected Sample Sample Name Testing Water Level MATERIAL DESCRIPTION s c U REMARKS 12 3 1 "m, AC \2 inches asphalt concrete walkway J 1 6 12 2 6 2 3A SM - Brown silty fine to medium sand (very loose, moist) (alluvium) 1 1 18 1 18 1 18 11 12 18 4 10 10 12 2 38 o %F 5 6 SA 6A SM Brown silty fine to medium sand (loose, moist) - (alluvium) - Grades to wet - _ Grades to medium dense with trace organic - matter (small roots) _ - _ — 33 33 43 47 Groundwater observed at 12 feet at time of drilling I Da Mc ML ML _ Light gray silt with trace horizontally oriented organic matter (fine fibrous wood fragments) - (soft, moist) (alluvium) - 60 12 1 18 23 9 9 10 SP-SM _ Gray fine to coarse sand with silt (medium dense, _ wet) (alluvium) - _ — — 26 10 118 37 11 SAND STONE Sandstone: white, visually fresh, fine grained — (Puget Group Tiger Mountain formation) Driller indicated different drilling conditions at approximately 34 feet Note: See Figure A-1 for explanation of symbols. Log of Boring B-2 GEOENGINEERS,G Project: Green River Bank Design and Permitting Project Location: Tukwila, Washington Project Number: 21493-001-01 Figure A-3 Sheet 1 of 1 21943-001-00 SST:LJS 04-28-2015 t-V 3ZIf10IA Sl1fS321 SISAWNV 3AGIS PERCENT PASSING BY WEIGHT 100 90 80 70 60 50 40 30 20 10 0 U.S. STANDARD SIEVE SIZE 3" 1.5" 3/4" 3/8" #4 #10 #20 #40 #60 #100 #200 1000 100 0 10 0 1 GRAIN SIZE IN MILLIMETERS 01 0.01 0.001 BOULDERS COBBLES GRAVEL SAND COARSE FINE COARSE MEDIUM FINE SILT OR CLAY SYMBOL EXPLORATION NUMBER DEPTH (ft) USCS SOIL CLASSIFICATION 0 B-2 B-1 17.5 10 Gray silty sand (SM) Brown silty sand (SM) ■ APPENDIX B Permit Level Design Drawings 0 OD TAB:COVER S 01\00\CAD \214930 hi 5133rd 5t Qa Jr 3Q rh FOSTER r 4 J r37Sh St t Camp 0 5 140th Sty 140th St U Showalter Middle School foster Nigh School S 144th St 5t 5 160th St S 146th St f. 0 5 150th St Sou S 156th St 5 164th 5t 5 166th St 116 La 5 139th St 0 0 • Crystal Springs Park '1 yb D S 144th St S 150th St 3D o� rh.or o°C' 5P Ro'S Foster Gott Links 5 147th 5t L 4 � M 5 152nd St rL, LD SCHNIEDER GREEN RIVER BANK REPAIR TUKWILA, WASHINGTON BLACK RIVER 5143rd Sr JUNCTION S 143rd PI 5 130th St S Langston Rd S Langston Rd 5 132nd St 5j32nd St S 133rd 5t 81ark River Quarry PROJECT SITE ion Dent Park 149th S x • r '"S S 153rd St Tukwila Park UICWIla wy Tukwil e. e c Southrenter Mall D VICINITY MAP SCALE: 1 "=100' 65 O p ze Baker Blvd Strander Blvd Treck Dr GRAPHIC SCALE 1000 0 1000 FEET 5 < p n is S 132nd St S 132n 5 134th St 5 135th St Blwk River Riparun Forest and Wetland 0 r n Tukwt5 v- SW 16th St SW 27th,r 0 D 0 SHEET INDEX: 1 VICINITY MAP AND SITE MAP 2 NOTES AND SPECIFICATIONS 3 SITE PLAN 4 CROSS —SECTIONS 5 DETAILS SITE MAP SCALE: 1 "=400' GRAPHIC SCALE 400 0 400 FEET FOR PERMIT REVIEW - NOT FOR CONSTRUCTION RE Description Date By Chk Rev DESIGNED LJS DRAWN TJM DATE 05/27/15 I FILE NO. 21493-001-01 SCALE AS NOTED IREVISED. 00/00/00 CHECKED JMA__._. Pus�° GEOENGINEERS 45765 ST0,t,1 L E. LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON VICINITY MAP AND SITE MAP SHEET 1 ES AND DETAILS MODIFIED BY "MICHAUD ON JUN II, 2015 - 9:04 GENERAL NOTES: 1. THESE DESIGNS AND DRAWINGS HAVE BEEN PREPARED FOR THE EXCLUSIVE USE OF LD SCNEIDER, AND THEIR AUTHORIZED AGENTS. NO OTHER PARTY CAN RELY ON THE PRODUCT OF OUR SERVICES UNLESS GEOENGINEERS INC. (GEOENGINEERS) AGREES IN WRITING IN ADVANCE OF SUCH USE. 2. THE DRAWINGS CONTAINED WITHIN SHOULD NOT BE APPLIED FOR ANY PURPOSE OR PROJECT EXCEPT THE ONE SPECIFIED. 3. THESE DESIGNS AND DRAWINGS ARE COPYRIGHTED BY GEOENGINEERS, INC. ANY USE, ALTERATION, DELETION, OR EDITING OF THIS DOCUMENT WITHOUT EXPLICIT WRITTEN PERMISSION FROM GEOENGINEERS IS STRICTLY PROHIBITED. ANY OTHER UNAUTHORIZED USE OF THIS DOCUMENT IS PROHIBITED. 4. THE CONTRACTOR SHALL CONSTRUCT THE PROJECT IN ACCORDANCE WITH THE PLANS STAMPED "APPROVED FOR CONSTRUCTION." THESE PLANS WILL BE PROVIDED TO THE CONTRACTOR BY THE ENGINEER OR PROJECT INSPECTOR PRIOR TO CONSTRUCTION. WORK SHALL NOT BE INITIATED WITHOUT THE PLANS APPROVED FOR CONSTRUCTION. 5. THE DESIGNS DEPICTED HEREIN ARE APPROXIMATE AND ARE INTENDED TO EXPRESS THE OVERALL DESIGN INTENT OF THE PROJECT. THESE DESIGNS MAY NEED TO BE ADJUSTED IN THE FIELD DURING CONSTRUCTION IN ORDER TO MEET THE SPECIFIC SITE CONDITIONS AND INTENDED FUNCTION. THESE RIVER IMPROVEMENTS HAVE BEEN DEVELOPED WITH THE UNDERSTANDING THAT A QUALIFIED GEOENGINEERS ENGINEER AND/OR SCIENTIST BE ON -SITE TO PROVIDE CONSTRUCTION GUIDANCE WHILE THE PROJECT IS CONSTRUCTED. 6. CONDITIONS CAN CHANGE AND THESE DESIGNS ARE BASED ON CONDITIONS THAT EXISTED AT THE TIME THE DESIGN WAS PERFORMED. THE RESULTS OF THESE DESIGNS MAY BE AFFECTED BY THE PASSAGE OF TIME, BY MANMADE EVENTS SUCH AS CONSTRUCTION ON OR ADJACENT TO THE SITE, OR BY NATURAL EVENTS SUCH AS FLOODS, EARTHQUAKES, SLOPE INSTABILITY OR GROUNDWATER FLUCTUATIONS. ALWAYS CONTACT GEOENGINEERS BEFORE APPLYING THESE DESIGNS TO DETERMINE IF THEY REMAIN APPLICABLE. 7. THESE PLANS AND ELECTRONIC DRAWINGS ARE BASED ON WASHINGTON STATE PLANE NORTH COORDINATES US FEET AND A NORTH AMERICAN VERTICAL DATUM OF 1988 US FEET. ELEVATIONS AND NORTHINGS AND EASTINGS WITHIN THIS PLANSET ARE BASED ON THESE DATUMS. CONSTRUCTION NOTES: 1. CONTRACTORS WORKING WITHIN THE PROJECT BOUNDARIES ARE RESPONSIBLE FOR COMPLIANCE WITH ALL APPLICABLE SAFELY LAWS. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL BARRICADES, SAFETY DEVICES AND CONTROL OF TRAFFIC WITHIN AND AROUND THE CONSTRUCTION AREA. 2. MATERIAL AND WORKMANSHIP FURNISHED ON OR FOR THE PROJECT MUST MEET THE MINIMUM REQUIREMENTS OF PROJECT PERMITS, APPROVING AGENCIES, SPECIFICATIONS AS SET FORTH HEREIN, OR WHICHEVER IS MORE RESTRICTIVE. 3. THE CONTRACTOR SHALL INSTAI I. AND MAINTAIN APPROPRIATE SEDIMENT CONTROL DEVICES THROUGHOUT THE WHOLE PROJECT SITE, INCLUDING THE CONSTRUCTION STAGING AREA AND STOCKPILE AREA THROUGHOUT THE PROJECT'S CONSTRUCTION. TEMPORARY CONSTRUCTION AND PERMANENT EROSION CONTROL MEASURES SHALL BE DESIGNED, CONSTRUCTED AND MAINTAINED IN ACCORDANCE WITH APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS. 4. CONSTRUCTION SHALL OCCUR DURING THE APPROVED WDFW FISH WINDOW FOR THE PROJECT AREA. 5. DISCHARGES ENTERING ACTIVE STREAMS ON -SITE SHALL SATISFY ALL STATE AND FEDERAL STANDARDS AND PROJECT PERMIT REQUIREMENTS FOR CONTAMINANTS AND TURBIDITY. SPECIFICATIONS: A. REFERENCED SPECIFICATIONS ARE FROM THE 2014 VERSION OF THE WSDOT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION. MATERIALS: A. RIVERBANK FILL 1. RIVERBANK FILL SHALL CONSIST OF WELL GRADED SAND AND GRAVEL CONFORMING TO EITHER WSDOT STANDARD SPECIFICATION 9-03.10 "AGGREGATE FOR GRAVEL BASE", 9-03.12(2) "GRAVEL BACKFILL FOR WALLS", 9-03.13(1) "GRAVEL BORROW", 9-03.13(2) "SELECT BORROW", OR OTHER MATERIALS AS APPROVED BY THE GEOTECHNICAL ENGINEER. NATIVE ALLUVIUM FROM THE EXISTING RIVERBANK MAY BE INCORPORATED INTO THE RIVERBANK FILL PROVIDED THAT THE ALLUVIUM CONTAINS LESS THAN 30 PERCENT FINES (MATERIAL PASSING THE NO. 200 SIEVE) BY WEIGHT OR AS APPROVED BY THE GEOTECHNICAL ENGINEER. 2. RIVERBANK FILL SHALL BE FREE OF ORGANICS OR OTHER DELETERIOUS MATERIALS. B. DRAINAGE ROCK 1. DRAINAGE ROCK SHALL MEET WSDOT STANDARD SPECIFICATION 9-03.12(2) "GRAVEL BACKFILL FOR WALLS." C. DRAIN PIPE 1. DRAIN PIPE SHALL CONSIST OF 4-INCH SCHEDULE 40 PVC PIPE. THE PIPE SHALL BE SOLID OR PERFORATED AS INDICATED ON THE PROJECT PLANS. THE PIPE AND CONNECTIONS SHALL MEET AASHTO SPECIFICATION M 278. PIPE CONNECTIONS AND DETAILING SHALL BE IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. 2. PERFORATED DRAIN PIPE INSTALLED PARALLEL TO THE SLOPE AND SHALL CONNECT TO SOLID DRAIN D. 1. PIPES (OUTLET DRAINS) THAT DAYLIGHT TO THE SLOPE FACE. SOLID DRAIN PIPES SHALL BE SPACED NO MORE THAN 20 FEET APART. SOLID DRAIN PIPES SHALL DISCHARGE ON AN EROSION PROTECTION PAD OR EXTEND TO THE BASE OF THE EXISTING SLOPE. EROSION PROTECTION PADS SHALL BE CONSTRUCTED OF MATERIAL CONFORMING TO WSDOT STANDARD SPECIFICATION 9-03.9(2) "PERMEABLE BALLAST'. THE EROSION PROTECTION PADS SHALL BE FIELD FIT BY THE ENGINEER AT THE DISCHARGE LOCATIONS AND SHALL HAVE A MINIMUM THICKNESS OF 6-INCHES, MINIMUM LENGTH (PARALLEL TO SLOPE) OF 2 FEET, AND MINIMUM WIDTH (PERPENDICULAR TO SLOPE) OF 1 FOOT. NON -WOVEN GEO-TEXTILE NON -WOVEN GEO-TEXTILE SHALL MEET WSDOT STANDARD SPECIFICATION 9-33.1 "GEOSYNTHETIC MATERIAL REQUIREMENTS" FOR NON -WOVEN GEO-TEXTILES USED FOR SEPARATION. E. RECYCLED MATERIAL 1. RECYCLED MATERIAL SHALL NOT BE USED IN AGGREGATES OR FILL. F. 1. TOPSOIL TOPSOIL SHALL CONSIST OF A COMMERCIALLY AVAILABLE 3-WAY MIXTURE CONSISTING OF LOAM SOIL, ORGANICS AND COMPOST PASSING 34-INCH SIEVE. G. EROSION CONTROL BLANKET 1.EROSION CONTROL BLANKET SHALL COMPLY WITH WSDOT STANDARD SPECIFICATION 9-14.5(2)D "BIODEGRADABLE EROSION CONTROL BLANKET FOR DITCHES. THE EROSION CONTROL BLANKET SHALL BE 100-PERCENT BIODEGRADABLE INCLUDING THE MESH BACKING. EXECUTION: A. SUBGRADE PREPARATION 1. SUBGRADES SHALL BE CLEARED AND GRUBBED. REMOVE BRUSH, SOD, OR OTHER ORGANIC OR DELETERIOUS MATERIALS PRIOR TO THE PLACEMENT OF FILL. SOFT AREAS SHALL BE OVEREXCAVATED AND REPLACED, AS DIRECTED BY GEOTECHNICAL ENGINEER. 2. SUBGRADE SHALL BE APPROVED BY GEOTECHNICAL ENGINEER. SUBGRADE SOILS SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION BEFORE CONSTRUCTION PROCEEDS. SUBGRADE MATERIALS NOT MEETING GEOTECHNICAL ENGINEER'S APPROVAL SHALL BE REMOVED AND REPLACED WITH RIVERBANK FILL AT DIRECTION OF GEOTECHNICAL ENGINEER. 3. OVEREXCAVATED AREAS SHALL BE REPLACED WITH COMPACTED RIVERBANK FILL MATERIAL. B. SLOPE PREPARATION 1. EXISTING SLOPES SHALL BE RE -GRADED AS REQUIRED TO INSTALL SPECIFIED IMPROVEMENT AND TO MAINTAIN A SAFE WORK ZONE. THE CONTRACTOR IS RESPONSIBLE FOR MAINTAINING A SAFE WORK ZONE AND COMPLYING WITH THE PROVISIONS OF TITLE 296 WASHINGTON ADMINISTRATIVE CODE (WAC), PART N, "EXCAVATION, TRENCHING AND SHORING." 2. FILL PLACED ON OR ADJACENT TO SLOPES SHALL BE PLACED ON HORIZONTAL BENCHES CUT INTO THE EXISTING SLOPE. 3. BENCHES SHALL EXTEND A MINIMUM OF 2-FEET HORIZONTALLY INTO THE SLOPE AND MAY BE CUT IN STAGES AS THE FILL PROGRESSES. C. FILL PLACEMENT AND COMPACTION 1. FILL MATERIAL SHALL BE PLACED IN LOOSE LIFTS NOT EXCEEDING 12-INCHES AND COMPACTED USING EQUIPMENT DESIGNED FOR SOIL COMPACTION. 2. FILL SHALL BE UNIFORMLY COMPACTED TO A MINIMUM 90 PERCENT OF MAXIMUM DRY DENSITY (MDD) AS DETERMINED BY ASTM D-1557. D. SITE REVEGETATION 1. TOPSOIL SHALL BE LOOSELY PLACED ABOVE THE RIVERBANK FILL TO A DEPTH OF 12 INCHES. THE FINISH GRADE SHALL BE TAMPED FIRM AND PROTECTED FROM EROSION. 2. THE EROSION CONTROL BLANKET SHALL BE SHINGLED OR PLACED IN A MANNER SUCH THAT RIVER FLOWS AND WIND DO NOT PEEL UP THE FABRIC. THE EROSION CONTROL FABRIC SHALL BE ANCHORED FOLLOWING THE MANUFACTURER'S INSTRUCTION. 3. NATIVE PLANTS, IDENTIFIED IN THE PLANT SCHEDULE, SHALL BE INSTALLED FOLLOWING THE LAYOUT PROVIDED BY THE GEOENGINEERS BIOLOGIST. PLANTS SHALL BE INSTALLED THROUGH THE EROSION CONTROL FABRIC BY CUTTING THE FABRIC TO THE MINIMUM NECESSARY TO INSTALL THE PLANTS. E. SITE MAINTENANCE AND MONITORING 1. THE SITE WILL BE MAINTAINED BY THE OWNER INTO PERPETUITY AND IN COMPLIANCE WITH THE PROJECT PERMITS. 2. THE SITE WILL BE MONITORED FOR A PERIOD OF FIVE YEARS FOLLOWING PLANT INSTALLATION AS SPECIFIED IN THE DESIGN AND ANALYSIS REPORT BY GEOENGINEERS OR AS REQUIRED BY THE PROJECT PERMITS. ANTICIPATED MATERIAL SCHEDULE APPROXIMATELY 420 YD3 OF CUT AND FILL: • -160 YD3 OF NATIVE MATERIAL TO REMAIN ON SITE. • -160 YD3 OF IMPORTED RIVERBANK FILL. • YD3 OF IMPORTED TOPSOIL. • '-3 YD3 OF 1-INCH DRAIN ROCK. • -1 YD3 OF IMPORTED OUTFALL PROTECTION. FOR PERMIT REVIEW - NOT FOR CONSTRUCTION Description Dote By Chk Rev DESIGNED LJS DRAWN TJM CHECKED JMA DATE 05127/15 FILE NO. 21493-001-01 SCALE AS NOTED REVISED: 00100(00 • '. 0SE P/y vW4S To'. A GEOENGINEERS 503 Stewart Street, SJite 1100 F. 2"6-728-2674 Seattle, WA 98101 F: 206 728- ,32 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON NOTES AND SPECIFICATIONS SHEET 2 / OHWM °HWM ASPHALT TRAIL 100' WIDE TYPOS RIVER BUFFER & URBAN CONSERVANCY BUFFER \\\ &1- \\ COMMERCIAL BUILDING OHWM LEGEND BORING LOCATIONS" EXISTING CONTOURS PROPOSED BANK LINES ORDINARY HIGH WATER MARK LIMITS OF WORK SILT FENCE \\\ BORING LOGS PROVIDED IN ACCOMPANYING REPORT (GEOENGINEERS 2015) VERTICAL DATUM. NAVD88 STONE BENCH OHWM B-1 GREEN RIVER OH WM EL=10.0' OHWM OHWM CC v~i OHWM STONE BENCH 34" SYCAMORE PLAN VIEW SCALE: 1 "=10' 24" SYCAMORE SCALE 10 0 10 FEET OUTLET DRAIN (TYP.) OHWM LIMITS OF WORK 24" SYCAMORE BOTTOM OF FILL SLOPE r SILT FENCE OHWM 30" SYCAMORE ARK\N� LOT �� OHWM X � 30" SYCAMORE OHWM 0 24" SYCAMORE ti� OHWM con, TOP OF EXISTING SLOPE 41" SYCAMORE PROTECT TREES PER CITY REQUIREMENTS (TYP-) 0149 FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Dote By Chk Rev 4- DESIGNED _LLS _ DATE OS z7115 DRAWN TJM SCALE AS NOTED CHECKED JMA FILE NO. 21493-001-01 REVISED: 00100100 ',OSF.PH avY. -�F Vlly 1. t1�. q'c wS/O.VAL F.l, GEOENGINEERS 6C0 Stewart Street, SJite 1700 F: 236-728-2674 Seattle, 'NA 28101 F. 21:6-728-7'NA 28101 11 216- %28-T3? LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON SITE PLAN SHEET 3 i \ 24" SYCAMORE (PROTECT TREE PER CITY REQUIREMENT) 30 20 — 10 PARKING LOT Iz— LANDWARD LIMITS OR WORK 1 EXISTING ASPHALT TRAIL - - ------------- TOP SOIL EXISTING GRADE RIVERBANK FILL EROSION CONTROL FABRIC N SEE ANCHOR TRENCH DETAIL CUT AS REQUIRED FOR SAFETY AND STABILITY 2% SEE DRAIN DETAIL --' OUTLET DRAIN — SEE ANCHOR TRENCH DETAIL OUTFALL PROTECTION PER MATERIAL NOTE C-2 - 30 BASE FLOOD ELEVATION SILT FENCE (WATERWARD LIMITS OF WORK) OHWM 20 10 0 1 1 1 1 1 1 1 1 0 0 10 20 30" SYCAMORE (PROTECT TREE PER CITY REQUIREMENT) 30 — 20 — 10 — PARKING LOT SECTION 30 40 Distance (Feet) 50 60 A HORIZONTAL SCALE 1"=5' VERTICAL SCALE: 1 "=5' LANDWARD EXISTING ASPHALT TRAIL SEE ANCHOR TRENCH DETAIL LIMITS OR WORK CUT AS REQUIRED FOR SAFETY AND STABILITY SEE DRAIN DETAIL 2.5 -11 C-2 EXISTING GRADE TOP SOIL 2% 70 80 85 RIVERBANK FILL - EROSION CONTROL FABRIC - BASE FLOOD ELEVATION • — — • — • — - — • — — - 20 SEE ANCHOR TRENCH DETAIL 30 OUTFALL PROTECTION PER MATERIAL NOTE C-2 SILT FENCE (WATERWARD LIMITS _ OF WORK) OHWM 0 20 SCALE SECTION 0 5 FEET 30 40 Distance (Feet) 50 B HORIZONTAL SCALE: 1"=5' VERTICAL SCALE: 1"=5' C-2 60 70 10 0 80 FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description t Date i By Chk Rev __4 DESIGNED LJS DRAWN __TJM CHECKED JMA _ DATE 00127115 _ FILE NO. 21493-001-01 SCALE _AS -NOTED_ _ REVISED. 00/00100 .Sp3Py of wa;\Aos \4 45765 0, ,� 70NAL GEOENGINEER_ 6�J Stewart Street. SJite 1777 206-728-2674 Seattle. WA 9810' L,6-'29-T73i LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON CROSS -SECTIONS AND DRAIN DETAIL SHEET C-3 N AUD ON JUN II, 2015 - 9:0B P:\21\21493001\00\CAD\21493001-01 DESIGN SHE 4" SCH40 PERFORATED PVC DRAIN PIPE EL. 15.0' RIVERBANK FILL 12" DRAIN DETAIL NON —WOVEN GEOTEXTILE SOLID SCH40 PVC OUTLET DRAIN 2% NATIVE SOIL NOT TO SCALE Recommended Planting Schedule Estimated Common Name Scientific Name Size Spacing Quantity 5 Black cottonwood Populus balsamifera 6 - 8 feet in height 10 feet o.c. 9 Western red cedar Thuja plicata 6 - 8 feet in height 10 feet o.c. 5 Big leaf maple Acer macrophyllum 6 - 8 feet in height 10 feet o.c. 5 Pacific dogwood Corpus nutalli 6 - 8 feet in height 10 feet o.c. 25 Vine maple Acer circinatum 6 - 8 feet in height 10 feet o.c. 25 Oceanspray Holodiscus discolor 24-inch in height 5 feet o.c 25 Snowberry Symphoricarpos albus 24-inch in height 5 feet o.c 25 Western serviceberry Amelanchier alnifolia 24-inch in height 5 feet o.c 25 Red osier dogwood Corpus sericea 24-inch in height 5 feet o.c JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATTACH FABRIC TO POSTS. II b~ 41,111 I I 7II'7II IIIE�I/ 6' MAX. MINIMUM 4"x4" TRENCH % 2"x2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBLE BACKFILL TRENCH WITH NATIVE SOIL OR 3/4"-1.5" WASHED GRAVEL \ 2"x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT SILT FENCE DETAIL NOT TO SCALE v Xer W 2X ROOT BALL WIDTH EROSION CONTROL FABRIC LOOSEN AND/OR CUT CIRCLING ROOTS IN ROOT BOUND CONTAINERS BEFORE PLANTING BREAK UP SIDES AND BOTTOMS OF PLANTING PIT TO ALLOW FOR ROOT PENETRATION COMPACT SUBGRADE BELOW ROOT BALL PLANT SCHEDULE TYPICAL PLANTING DETAIL FOR PERMIT REVIEW - NOT FOR CONSTRUCTION REV Description Date By Chk Rev DESIGNED LJS _ I DRAWN TJM _ CHECKED JMA DATE 05/27/15 FILE N0. 21493=001-01 SCALE AS NOTEDREVISED. 00 OQ/00 GEOENGINEER_ 600 Stewart Street. Suite 1700 n: 2C5-728-2674 Seat0e, WA 9810' 206-728-2732 LD SCHNIEDER- GREEN RIVER BANK REPAIR 14900 INTERURBAN AVENUE TUKWILA, WASHINGTON DETAILS SHEET 5 APPENDIX C Project Value Documentation LB Schneider Green River Bank Repair - Project Value Documentation 14900 Interurban Avenue South Tukwila, Washington Description Description of Quantity QTY per foot of repair Unit Unit Cost (Total + O&P) Total for Foot of Repair Project Total Based on 160 Feet of Repair Excavation and Haul Riverbank Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY $17.00 $0.00 $0.00 Subtotal Subsurface Drainage Fabric Laid in Trench RS Means 1.3 SY $2.42 $3.15 $503.36 Drainage Material RS Means 0.22 CY $34.00 $7.48 $1,196.80 6-in PVC Perforated RS Means 2 LF $14.45 $28.90 $4,624.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0.126 TON $48.00 $6.05 $967.68 Subtotal $42.43 $6,788.48 Foundation Preparation Foundation Excavation Including Haul & Disposal Bid Tab 1060 From B&D Levee Project 0 CY $17.00 $0.00 $0.00 Rock for Erosion & Scour Protection (Class A) Bid Tab 1326 B&D Levee 0 TON $48.00 $0.00 $0.00 Subtotal $0.00 $0.00 Fill Placement and Compaction Gravel Borrow Including Haul and Compaction Bid Tab 1075 from B&D Levee Project 5.53 TON $20.00 $110.60 $17,696.00 Geo-Grid Soil Reinforcement RS Means 0 SF $0.81 $0.00 $0.00 Jute Mesh Bid Tab 8025 from B&D Levee Project 0 SY $1.30 $0.00 $0.00 Subtotal $110.60 $17,696.00 Erosion Control, Surface Treatments, and Plantings TESC Bid Tab Schedule VII B&D Levee 1 LF of River $51.28 $51.28 $8,204.80 Landscaping Bid Tab Schedule VIII B&D Levee 1 LF of River $100.00 $100.00 $16,000.00 Subtotal $151.28 $24,204.80 Mobilization, Contingency, Misc., and Totals Total Unit Costs $262 $41,901 Mobilization Assumed Values 10.0% LS $26 $4,190 Contingency Assumed Values 15.0% LS $39 $6,285 Miscellaneous Costs Assumed Values 10.0% LS $26 $4,190 Sales Tax Washington State 9.5% LS $25 $3,981 Estimated Totals $378 $60,547 1 1 f Chi OF TUKWILA Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 SHORELINE SUBSTANTIAL DEVELOPMENT PERMIT INFORMATION State Shoreline requirements are implemented through the Shoreline Overlay District in the Tukwila Zoning Code (Tukwila Municipal Code (TMC) 18.44). Tukwila's shoreline regulations were updated in October, 2011 when the Department of Ecology approved the City's new Shoreline Master Program (SMP). REQUIREMENTS: All development over $6,416 land within 200 ft. of the Duwamish/Green River and associated wetlands require a "Shoreline Substantial Development Permit" except the following: • Owner -occupied construction of a single family house that does not exceed 35 feet in height and/or dock construction when the dock construction costs are less than $2,500 in salt water and $10,000 in fresh water; • Normal maintenance and repair; • Habitat improvements which are part of a watershed plan; • Hazardous waste remediation when approved by the State; • Emergency construction needed to protect property from imminent danger. While a project may be exempt from the need to obtain a Shoreline Substantial Development Permit, the project must still be consistent with the requirements of Tukwila's SMP. The Director may impose conditions on the approval of exempt developments and/or uses as necessary to assure compliance of the project with the Shoreline Management Act and the City's SMP. PROCEDURES: Your application must contain all of the items listed on the attached "Complete Application Checklist" including Project Value Documentation. You may request a waiver from items on the checklist that are not applicable to your project. Please discuss this waiver request with City planning staff prior to submitting the application. Within 28 days of receiving your application, City staff will determine if it is complete based on the attached checklist. If the application is not complete, City staff will contact you about what additional information is needed. If you do not submit the requested materials within 90 days from the City's request for additional information, the City may cancel your application. A shoreline permit decision is made administratively by the Director of the Department of Community Development after the expiration of the public notice period. The City's decision is sent to the Department of Ecology for its review. There is a 21 day appeal period on Shoreline Substantial Development Permits and no construction may occur during that time, although building permits may be reviewed. EXPIRATION: Construction must begin within two years of permit approval and be completed within five years. ' Starting in 2007, the dollar threshold trigger for substantial development is adjusted every 5 years, to reflect increases in the Consumer Price Index. CPL Page 1 of 10 07/17/2014 10:16 AM W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP Permit COMPLE APPLICATION ECKLIST The materials listed below must be submitted with your application unless specifically waived in writing by the Public Works Department and the Department of Community Development. Please contact each Department if you feel that certain items are not applicable to your project and should be waived. Application review will not begin until it is determined to be complete. ADDITIONAL MATERIALS MAY BE REQUIRED. The initial application materials, once deemed complete, allow project review to begin and vest the applicant's rights. However, the City may require additional information as needed to establish consistency with development standards. City staff are available to answer questions about application materials at 206-431-3670 (Department of Community Development) and 206-433-0179 (Department of Public Works). Check items submitted with application Information Required. May be waived in unusual cases, upon approval of both Public Works and Planning. APPLICATION MATERIALS: 11 1. Application Checklist (1 copy) indicating items submitted with application. 1 2. Completed Application Form (page 7) and notarized Hold Harmless Agreement (page 9) (5 copies). 3. Application Fee: See Land Use Fee Schedule for Standard App fee. "11 4. Project value Documentation. See GeoEngineers Report Appendix C 5. Public Notice Materials and fee. See item A (page 4) for details. �/ 6. Project Description/Analysis (5 copies) and other environmental reports (2copies). See item B (page 4) for details. 7. Drawings (5 copies) Additional copies may be required upon determination that the application is complete: a). Site Plan See item C (page 4) for details. b). Site Cross Sections along the shoreline . See item D (page 5) for details. c). Landscape Plans. See item E (page 5) for details. d). Civil Plans. See item F (page 5) for details. e). Other plans to help explain the project such as elevations, lighting plan, signage etc. See item G (page 6) for details. 8. One set of all plans reduced to 8 1/2" by 11" or 11" by 17". 9. An electronic copy of all project application materials. 10. Other land use applications, as applicable: SEPA Environmental Checklist, Design Review Application (see TMC 18.44.110 for review criteria), Special Permission, Director, for buffer reduction requests. A. PUBLIC NOTICE MATERIALS: 1. Payment of notice board fee (see Land Use Fee schedule) to Fast Signs Tukwila or Provide a 4' x 4' public notice board on site within 14 days of the Department determining that a complete application has been received (see Public Notice Sign Specifications Handout). 2. Pay the fee as established by the Land Use Fee Schedule for generating mailing labels; Or provide CPL Page 2 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP Permit 07/17/2014 10:16 AM / \ l \ Check items submitted with application Information Required. May be waived in unusual cases, upon approval of both Public Works and Planning. an excel spreadsheet of mailing labels for all property owners and tenants (residents and businesses) within 500 feet of the subject property. Each unit in multiple family buildings e.g. apartments, condos, trailer parks --must be included. Once your project is assigned to a planner, you will be required to provide an electronic copy of the mailing label spreadsheet in the following format: Name, Street Address, City St Zip, with each of these fields as an individual column: Name Street Address City, St, Zip Mr. Smith 1234 Park Ave S Tukwila WA 98188 PLEASE NOTE: Regardless of whether you pay the City to generate the mailing labels or you provide them, there is an additional fee for postage and material as listed under Public Notice Mailing Fee on the Land Use Fee Schedule. You will receive a separate bill for this fee and payment is due prior to issuance of the decision. 3. If providing your own labels, include King County Assessor's map(s) which highlights each property within 500 feet of the project, and are included on the mailing list. B. PROJECT DESCRIPTION/ANALYSIS AND OTHER ENVIRONMENTAL REPORTS: 1. Vicinity Map with site location - does not have to be to scale. 2. Provide: a) a written discussion of project consistency with the Review Guidelines(see page 11), or a reference on plan sheets illustrating compliance with the Review Guidelines; and b) a response to the No Net Loss Checklist (see pages 13-14). Check with a planner if you are unsure what criteria apply to your project. 3. Provide two copies of sensitive area studies if needed per TMC 18.44.090 D (Environmentally Sensitive Areas within the shoreline jurisdiction section of the SMP). 4. Provide an analysis of river bank stability if alteration of the riverbank is proposed. See TMC 18.06.696 for the definition of a riverbank analysis and report. 5. Provide two copies of any other studies prepared for the project (Biological Assessment etc.). C. SHORELINE SITE PLAN: 1. The site plan must include a graphic scale, north arrow and project name. Maximum size 24" x 36". 2. Identify existing top of bank, landward and riverward toe of levee (or toe of bank if no levee), ordinary high water mark and base flood elevation (i.e., the 100 year flood). 3. For work riverward of the OHWM: Distance work extends into the river and distance to Federal projects and navigation channels. 4. Identify the location of the shoreline buffer (measured from the Ordinary High Water Mark) applicable to the shoreline environment in which the project is located: • Shoreline Residential Buffer - show where the top of the river bank would be at a 2.5:1 slope from OHWM and add twenty feet. If there is not enough room on the parcel for this buffer, the minimum buffer width is 50 ft.; • Urban Conservancy Buffer —100 ft. non -levee area; 125 ft. in leveed area; • High Intensity Buffer -100 ft. • The Aquatic Environment includes the area waterward of the OHWM and does not have an identified buffer. CPL Page 3 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP Permit 07/17/2014 10:16 AM Check items submitted with application Information l,_ quired. May be waived in unusual cases, upon approval of both Public Works and Planning. 5. Show any levee/riverbank maintenance easements. 6. Construction limit lines and areas of Bearing/grading/filling. See TMC 18.44.070 J for land altering regulations. Removal of any significant trees or native vegetation in the shoreline jurisdiction requires a Shoreline Tree Removal and Vegetation Clearing Permit. 7. Show public access and/or trails per TMC 18.44.100. 8. Show building footprint, parking lots, driveways, loading and service areas. See TMC 18.44.070 I for parking regulations. 9. Identify any sensitive areas and their buffers, as applicable. D. CROSS -SECTIONS FOR SHORELINE PROJECTS SHORELINE CROSS SECTIONS at maximum 75' intervals along the shoreline showing: 1. Existing and proposed elevations and improvements; 2. Limits of the applicable shoreline buffer and 200 foot shoreline jurisdiction, as measured from the OHWM; 3. The top of bank elevation, landward catch point toe of levee, riverbank toe, ordinary high water mark and base flood elevation (i.e., the 100 year flood as determined by the Federal Emergency Management Administration - FEMA), and levee/ riverbank maintenance easement and the location of the top of bank at a 2.5:1 slope. E. LANDSCAPE PLAN: 1. Landscape planting plan by a Washington State licensed landscape architect or an approved biologist. Plans must include the type, quantity, spacing and location of all plantings, soil preparation and amendment, irrigation, weed management, mulching and maintenance plan. Invasive vegetation must be removed and native vegetation planted. Maximum size 24" x 36". See TMC 18.44.080 for requirements. 2. Show all existing trees over 4" in caliper, indicating those to be retained, those to be removed and any tree protection measures required. Any trees removed over 4" in caliper are subject to the replacement requirements of TMC 18.44.080 B.4. 3. Provide notes on landscaping sheets that address consistency of landscaping with requirements of TMC 18.44. F. CIVIL PLANS: 1. One set of all civil plans and analyses shall be stamped, signed and dated by a licensed professional engineer. Include a graphic scale and north arrow. Maximum size 24" x 36". 2. Vertical datum NAVD 1988 and horizontal datum NAD 83/91. Conversion calculations to NGVD 1929, if in a flood zone or flood -prone area. See www.tukwilawa.gov/pubwks/bulletins/cablist.html , Bulletin A7 and related documents for further information. 3. Existing (dashed) and proposed (solid) topography at 2' intervals. 4. Construction limit lines, areas of clearing/grading/filling including volume and type of expected cut and fill. 5. Existing and proposed utility easements and improvements. 6. If additional impervious surface is proposed, provide a storm drainage design at least 90% complete, which meets the King County Surface Water Design Manual (KCSWDM). For guidance on preparation of the Technical Information Report contact the Public Works Dept. or go to: www.tukwilawa.gov/pubwks/pwpermit.html#SURFWATER. CPL Page 4 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Pemvts\4-11-12 SSDP Pennit 07/17/2014 10:16 AM Check items submitted with application Information Required. May be waived in unusual cases, upon approval of both Public Works and Planning. See also TMC 18.44.070 D for additional surface water regulations. 7. Show the 100 yr. flood plain boundary and elevation as shown on FEMA maps which are available at the Tukwila Public Works Department counter. 8. Show all site improvements including footprints of all existing and proposed buildings, paved areas and any shoreline stabilization structures proposed in the shoreline. See TMC 18.44.070 E. 9. Show fences, rockeries and retaining walls. 10. Show docks and other overwater structures. See TMC 18.44.070 K. G. OTHER PLANS: 1. If new construction is proposed, provide dimensioned and scalable building elevations with keyed colors and materials. Show mechanical equipment and/or any proposed screening. 2. If site lighting changes are proposed, provide a luminaire plan induding location and type of street and site lighting. Include proposed fixture cut sheets, site light levels (foot-candles), and what measures will be used to shield adjacent properties and the river from glare. 3. All existing and proposed signage with sign designs and locations. See TMC 18.44.070 L. 4. Any other drawings or materials needed to explain your proposal. CPL Page 5 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP Permit 07/17/2014 10:16 AM / °'‘'ZZ4) 7Z) CITY OF TUKWILA SHORELINE Department of Community Development SUBSTANTIAL 6300 Southcenter Boulevard, Tukwila, lYA „�-• 1 Telephone: (206) 431-3670 $ t “i L4i ED DEVELOPMENT SUN 242015 PERMIT APPLICATION FOR STAFF USE ONLY Permits Plus Type: P-SHORE Planner: File Number: L% 0 '--- s Application Complete (Date: ) Project File Number: pL/G ---r/__ Application Incomplete (Date: ) Other File Numbers: f l/ n.-- NAME OF PROJECT/DEVELOPMENT: Green River Bank Erosion Repair BRIEF DESCRIPTION OF PROJECT: Install a subsurface drainage system and restore an eroded bank on the Green River. LOCATION OF PROJECT/DEVELOPMENT: Give street address or, if vacant, indicate lot(s), block and subdivision, access street, and nearest intersection. 14900 Interurban Avenue South LIST ALL TAX LOT NUMBERS (this information may be found on your tax statement or NWMaps. net). Parcel #3597000006 PROJECT VALUE (PLEASE ATTACH DOCUMENTATION): Approximately $65,000 DEVELOPMENT COORDINATOR : The individual who: • has decision making authority on behalf of the owner/applicant in meetings with City staff, • has full responsibility for identifying and satisfying all relevant and sometimes overlapping development standards, and • is the primary contact with the City, to whom all notices and reports will be sent. Name: Thomas Bannister- GeoEngineers, Inc. Address: 600 Stewart Street, Suite 1700. Seattle, Washington 98101 Phone: (206) 728-2674 E-mail: tbter@geoengin-ers.com Signature: FAX: '73 Date: btkie.._ CPL Page 6 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP 07/17/2014 10:16 AM l \ CITY OF TUIKWILA Department of Community Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 AFFIDAVIT OF OWNERSHIP AND HOLD HARMLESS PERMISSION TO ENTER PROPERTY STATE OF WASHINGTON COUNTY OF KING The undersigned being duly sworn and upon oath states as follows: 1. I am the current owner of the property which is the subject of this application. 2. All statements contained in the applications have been prepared by me or my agents and are true and correct to the best of my knowledge. 3. The application is being submitted with my knowledge and consent. 4. Owner grants the City, its emplo ees, agents,�eigineers, contractors or other representatives the right to enter upon Owner's real I ` property, located at i Ct J U ZAP L AVE, �,t- .'OT H for the purpose of application review, for the limited time necessary to complete that purpose. 5. Owner agrees to hold the City harmless for any loss or damage to persons or property occurring on the private property during the City's entry upon the property, unless the loss or damage is the result of the sole negligence of the City. 6. Non -responsiveness to a City information request for ninety (90) or more days, shall be cause to cancel the application(s) without refund of fees. EXECUTED at Tt-i012.14 (x (city), A-Z (state), on J U.JG 5 , 20 /.5 (Print Namg) 320 tJO tb ex -An q..vP-. STE 11tx0,4z (Address) (Phone Number) ony (Signature) On this day personally appeared before me ,\\AR'A Inc ' ' (k' to me known to be the individual who executed the foregoing instrument and acknowledged that he/she signed the satne as his/her voluntary act and deed for the uses and purposes mentioned therein. SUBSCRIBED AND SWORN TO BEFORE ME ON THIS 1 DAY OF V U N- , 20 LAURA TUCKER Notary Pubilo • State °Arizona MARICOPA COUNTY My Commission Expires March 31, 2018 NOTARY PUBLIC in and for the of Washitigtei 14RtZ6++s residing at M G R(COpC J N'tvi My Commission expires on MC( .Cb 311 21)(' \\Deptstore\City Common\Ten1KIRBY - DECEMBER\SEPA Environmental Review Application-Jan2011.Docx / CITY OF TUKWILA Department of Comnruniry Development 6300 Southcenter Boulevard, Tukwila, WA 98188 Telephone: (206) 431-3670 AFFIDAVIT OF OWNERSHIP AND HOLD PERMISSION TO ENTER PROPERTY STATE OF WASHINGTON ss COUNTY OF KING The undersigned being duly swo and upon oath states as follows: 1. I am the current owner of the`.roperty which is the subject of this .a plication. 2. All statements contained in th:\applications have been prepared me or my agents and are true and correct to the best of my knowledge. 3. The application is being submitte with my knowledge and cosent. 4. Owner grants the City, its employe. , agents, engineers, con sactors or other representatives the right to enter upon Owner's real property, located at for the purpose of application revie for the limited t. - necessary to complete that purpose. 5. Owner agrees to hold the City harmless or any loss or amage to persons or property occurring on the private property during the City's entry upon the property, ess the I . s or damage is the result of the sole negligence of the City. 6. Non -responsiveness to a City information re Q uest for ety (90) or more days, shall be cause to cancel the application(s) without refund of fees. SS EXECUTED at (Print Name) (Address) (city), `, (state), on 20 (Phone Number) (Signature) On this day personally app ared before a to me known to be the individual who executed the foregoi g instrument d acknowledged that he/she si i ed the same as his/her voluntary act and deed for the uses and purposes m ntioned thereEn. SUBSCRIBED AND SWORN TO BEFORE ME ON THIS DAY OF NOT PUBLIC in and for the State of Washington residinaf at My CcJmmission expires on ,20 CPL Page 7 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP 07/17/2014 10:16 AM / REVIEW GUIDELINES Applicable City of Tukwila Shoreline Policies: Please provide a narrative discussion on how your project is consistent with or implements the applicable Shoreline Master Program goals and policies. A list of these goals and policies can be found in Chapter 6 of the Shoreline Master Program, see Attachment A to Ordinance 2344: http://www.tukwilawa.gov/dcd/shoreline.html . They are also available at the Tukwila Department of Community Development. Please discuss with a planner the goals and policies that should be addressed. Applicable City of Tukwila TMC 18.44, Shoreline Overlay District Criteria: City staff will review your project against the relevant criteria below. Please make sure you have addressed the appropriate requirements from TMC 18.44, Shoreline Overlay District in your project. Applicable to Project? Review Criteria and TMC References PERMITTED USES: The project will be reviewed to ensure the proposed use is consistent with TMC 18.44.030 - Shoreline Use Matrix, the uses permitted in the relevant shoreline environment and the underlying zoning: Shoreline Residential See TMC 18.44.040 Urban Conservancy See TMC 18.44.050 High Intensity See TMC 18.44.060 Aquatic See TMC 18.44.065 DEVELOPMENT STANDARDS: the project will be reviewed against the following development standards. Check with a planner if you have questions on whether a particular development standard applies to your project. Provide a written response to the development standards or cite a project drawing that responds to the relevant standard. General Shoreline Residential Environment Development Standards, TMC 18.44.070 B. High Intensity, Urban Conservancy and Aquatic Environment Development Standards, TMC 18.44.070 C. • General Standards • Setbacks and site configuration • Height Restrictions • Lighting VEGETATION AND LANDSCAPING TMC 18.44.080 The project will be reviewed for consistency with the SMP's vegetation and landscaping requirements. PUBLIC ACCESS TMC 18.44.100 The project will be reviewed for consistency with the public access requirements of the SMP. CPL Page 8 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP 07/17/2014 10:16 AM NO NET LOSS CHECKLIST What is No Net Loss? The Washington State Shoreline Management Act (SMA) requires protection of the natural resources and ecological functions of the shoreline environment. Ecological functions are processes that characterize the river and its shoreline and form habitats for water- and land -based wildlife and vegetation. Ecological processes depend on the geology, soil type, topography, climate, and other physical characteristics in the region. In the Green/Duwamish River watershed, key ecological processes include: • river flows, tidal fluctuations and saltwater influences; • creation, transport and deposition of sediment (for example scouring of soils, and erosion and formation of mud -flats or beaches); • transport of nutrients (from decomposition of plants and other organic materials); • provision of woody debris from fallen limbs and trees along the banks or in the water (the trunks and branches help form pools for fish); and • water quality (such as vegetation that can help to filter out pollutants that are washed into the river from parking lots and vegetation that can help reduce temperatures in the river, important for fish, especially salmon). These physical and biological processes comprise the ecological functions of the shoreline. The state guidelines that implement the SMA, adopted in 2003, establish the standard of "no net loss" of shoreline ecological functions for land uses and development within the shoreline jurisdiction. The No Net Loss standard is designed to stop the introduction of new negative impacts to shoreline ecological functions resulting from new development. Tukwila's Shoreline Master Program (SMP) defines no net loss as a: "...standard intended to ensure that shoreline development or uses, whether permitted or exempt, are located and designed to avoid loss or degradation of shoreline ecological functions that are necessary to sustain shoreline natural resources." In other words, the existing conditions of the shoreline ecological functions should not deteriorate due to new permitted development or new land use. A loss of ecological function can occur when a physical condition such as vegetation along the shoreline is removed or when habitat is altered through the construction of a dock or pier or other structures over this habitat. In order to maintain shoreline ecological functions, negative impacts must be mitigated to restore an equivalent amount of ecological function. The approach to mitigation must follow the mitigation sequencing steps adopted in the SMP (see next page). It should be noted that the SMA and the City's SMP also require improvement of shoreline functions, and therefore, some re -vegetation of the shoreline will be required in proportion to the scale of the project, regardless of whether there is a net loss to ecological functions. CPL Page 9 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP 07/17/2014 10:16 AM f\ On a separate sheet of paper, please respond to the following questions to evaluate your project's impacts and assist in analyzing whether there will be a net loss to shoreline ecological functions requiring mitigation: 1. Describe the existing condition of the shoreline area and riverbank. For example, what plants and how much vegetation currently exist within the 200 foot shoreline jurisdiction; what is the condition of the shoreline (how steep are the banks, is there any erosion or slope failure, what are the soils like); is there "hard armoring" on the riverbank (for example, concrete or wooden bulkheads, metal sheet piling, rip -rap [rocks or concrete/asphalt blocks]), is there paving or are there any structures within the 200 ft. shoreline jurisdiction; are there any docks, piers, decks or other structures near or over the water; are there any above -ground or below ground utilities; etc.? 2. How will your project change the existing condition of the shoreline described above? 3. Please respond to the questions in the following chart - A No Net Loss analysis (prepared by a qualified biologist) must be prepared if the response to any of the questions in the chart below is "yes": WILL THE PROJECT: NO YES a. Alter/remove vegetation in the shoreline jurisdiction? V b. Alter the river bank (i.e. re -slope bank, add armoring etc.)? J c. Add fill in the shoreline jurisdiction? J d. Discharge new stormwater to the river? V e. Store or use hazardous materials in the shoreline jurisdiction? V £ Construct an in- or over -water structure? V g. Increase impervious surface in the shoreline jurisdiction? V 4. The way to achieve no net loss of ecological function is to mitigate the loss through one or a combination of the mitigation sequencing steps identified below. If preparing a No Net Loss analysis, please discuss how your project addresses the following mitigation sequencing steps (TMC 18.44.070 H.3.): a. Avoiding the impact altogether by not taking a certain action or parts of an action; b. Minimizing impacts by limiting the degree or magnitude of the action and its implementation by using appropriate technology or by taking affirmative steps to avoid or reduce impacts; c. Rectifying the impact by repairing, rehabilitating, or restoring the affected environment; d. Reducing or eliminating the impact over time by preservation and maintenance operations; e. Compensating for the impact by replacing, enhancing, or providing substitute resources or environments; and f. Monitoring the impact and the compensation projects and taking appropriate corrective measures. CPL Page 10 of 10 W:\\Long Range Projects\Shoreline\New Shoreline Permits\4-11-12 SSDP 07/17/2014 10:16 AM