Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
SWP272149(3)
+r 00, Z8'E8/ POW o 5 NOS Nol�ivi�3'6'� -s;ndyv��i 91 0 $ 9d $ ya�,a� �� ms J� 6ae � �I 4n o�i°7�29 0/`6f ��' M££-�£-18N _ 00 L£'9£ £I , v ash 04 a -� &OC `yZZ $�` =�o� "A 8 6 ' £0$°ol1G 0�`� r � � 0� 5 L/�fyoL/I�! I l `i��yo \ 9 L yea I oJ •� o�' t- /! ! og I\ d / y' o� g Z 9 � y o �� �Moys y� 9 Y ��� ,1 '�o�d�t1 C 6y 5 / / ! !! 5•ooxn g� o�cyz L�,00Z��,o Xn �' +v�l ,%�,'�� N j� S'S •�� �gt� ! : ! !' �,� '� S . '° ' 1 I�b 6Z :'mow 0 \ 3 s tN-Z ! / ! I {g2� .tom , � �° qq t,•zz '� � Z of Gov �, al p% /1 S :5� . ;61b v tAl Z l 'ON tl 2 / ! ! 61 0-0° z / ,�pct •g�• Lr g'9�`' m Z N01N3� IZ / / / ,/y,l °6/ �{5 � 120% �e o�i y�'7y qO t 6 O w �061Ov ti� Z $Z O Z 4 o£ A 6� m 3 ,y I I Q N ALrz N � L CI 1 91 61OL z PU M m o 51 91 L' �o �cn 6s/� w o v2•z` Z �� a/�I i Uzi `� �� E� 1 qt >nQ'b�� s�ti� p �� 6Z o w .�'4 �� ���' �(I Odd` %° ego s �W61 S�"a ���y — S�z — ''�` �, Lo��ggs �� rg .d•S 'd 9 ,�•eb ���' . }1 � 0 1 0,0 6Sc �5'� o� � e5' ,6y,9°� M o005' � w p'� I ZS'�fO ��s \ ,.� S d - 1' � -6 '� d 6� 1 • o , m YZ o � , OS 3OG/' S /HZ/ ^^ }� •N•S `� yZ�+6�ZI � t7 Z : :jai `� £ � '62 � Zg 42l o•�.�• ,�.5 d P/ 6�,�6/'' �, •2 �� .-y9 '� °c� , �v,�Olr 32/ Z: S�stIWW °g�yl'S R; `''� / %6'z�%,� G 6� ` �� ' , yes ��•tr weyes , .i i s • �, � � a•gl� r � •f°�,OL� 001 • • '•' �N S � ,,'.S o�l,�tik 4 .n 4 i- y ,2.�L` \� o C,7•y01 S 2�'a� �d pil s � °q` .d ��'�Zg d)� �i d,70) ryZ,9LN �d 9 �1N qC4� o oL d , N �,y'L�' a\o yooZ� oEg° o N •p''7.� °N7,Y,� oQ6v� 6 • �,00 ` ,X n N` Washington State District t Department of Transportation 15700 Dayton Avenue North WOP.O. Box 330310 Sid Morrison Seattle,WA 98133-9710 Secretary of Transportation (206)440-4000 June 27, 1994 Scott Woodbury Project Manager City of Renton Surface Water Utility 200 Mill Avenue South Renton, WA 98055 SR-405 MP 1.59 Springbrook Creek/P-1 Channel Dear Mr. Woodbury: This letter will serve as a Construction Permit for the City of Renton to enter upon State right of way to accomplish work for the above noted project. The work performed on SR-405 right of way, Station 148+50 to 144+00, includes a pedestrian path. The City of Renton, by countersigning in the space provided below, acknowledges and agrees to the following stipulations to this Construction Permit. 1. Will utilize appropriate traffic control plans as found in the Manual on Uniform Traffic Control. 2. Will not perform any work from the traffic lanes on SR-405. 3. Will notify Sam Richard (440-4736) as to the time and place of the preconstruction meeting. 4. Agrees to hold the State harmless from any claims on legal actions directly related to work accomplished under this improvement. 5. Agrees to submit to WSDOT, the contractor's dewatering and bypass plans for approval. Scott Woodbury June 27, 1994 Page 2 The effective date of this Construction Permit is the date of countersigning by the City. We are transmitting the original and one (1) copy of this correspondence. Please sign, if satisfactory, and return the original to our office. Sincerely, --I�Oootc�� TERRENCE G. PAANANEN, P.E. Local Programs Engineer JS4 Public rks D' ctor f, Attest if q Ll Dat Attachments TP:SR:kn 0694sr09 CITY OF RENTON I DEVELOPMENT SERVICES DIVISION MASTER APPLICATION OWNER(S) PROJECT INFORMATION (cont) j Note: If there is more than one legal owner,please attach an EXISTING LAND USE(S): II additiona:notarized Master application for each owner. _ Most of the site is designated employment NAME area-office, with the balance classified CITY OF RENTON AND OTHERS. as employment area-industrial . Office-2.4 Property rights for the project acres; Industrial-0.4 acres between I-405 an ADDRESS: will be obtained prior to constructior SW 16th St and within east 1/2 of the SE 1/4 PP affi and NE 1/4 of Sec 24, T23N,R4E. EXISTING ZONING CITY ZIP: Portions of the project are zoned medium industrial (1M) and commercial office (CO) . 1M-1.2 acres between 1-405 and SW 16th St. TELEPHONE NUMBER of I-405 and so of SW 16t St, CONTACT PERSON/APPLICANT N/A NAME Ron Straka City of Renton PROPOSED ZONING Surface WaterUtility i ADDRESS 200 Mill Avenue South N/A CITY ZIP SITE AREA(SO. FT OR ACREAGE) Renton, WA 98055 Project area is approximately 3 1/4 acres. TELEPHONE NUMBER. fi 206 277-5548 PROJECT VALUE r PROJECT INFORMATION Approximately $600,000 I PROJECT OR DEVE:.OPMENT NAME IS THE SITE LOCATED IN AN ENVIRONMENTALLY SENSITIVE AREA') Springbrook Creek/P-1 Channel Improvement Yes. The site or portions of the site have! been classified as within or containing thele , PROPERTY/PROJECT ACDRESS(S)/LOCATION: I TN1' ITE LOC E�tr�,'AN�{�[)IPErR PIR4T81AIRA" wetlan s, ejtc. See legal description. No. I KING COUNTY ASSESSOR S ACCOUNT NUMBER(S) ! 2423049004 2423049126 IS THE SITE LOCATED IN THE SEWER MORATORIUM AREA? 2423049054 2423049022 3340406255 3340405300 No. LEGAL DESCRIPTION OF PROPERTY (Attach separate sheet if needed) j See attached. t TYPE OF APPLICATION & FEES Check all;.applicatI types that apply .City staff will determine fees. SUBDIVISION: _ANNEXATION $ _ REZONE $ _ LOT LINE ADJUSTMENT $ _SPECIAL PERMIT $ _ SHORT PLAT $ TEMPORARY PERMIT $ TENTATIVE PLAT $ —CONDITIONAL USE PERMIT $ 'u00, — X SITE PLAN APPROVAL $ __ — PRELIMINARY PLAT $ SPECIAL PERMIT $ _FINAL PLAT $ GRADE& FILL PERMIT $ (NO. CU. YDS: 15,700 cut) _X VARIANCE 8,100 fill $ PLANNED UNIT DEVELOPMENT: $ (FROM SECTION: 4-9-5.0 ) _WAIVER $ PRELIMINARY _ ROUTINE VEGETATION — MANAGEMENT PERMIT $ — FINAL BINDING SITE PLAN $ SHORELINE REVIEWS: MOBILE HOME PARKS: $ _X SUBSTANTIAL DEVELOPMENT $ (ti(v _TENTATIVE _ CONDITIONAL USE $ PRELIMINARY _VARIANCE $ _ FINAL _ EXEMPTION $ No Charge REVISION X ENVIRONMENTAL REVIEW $ Nc' (This s ctio be completed City staff) City File Number. CF SA R S H P L QIU LLA PP FP TP S5 RVMP QV:!)AAD W PUD S SME PMHP FMHP BSP A TOTAL FEES, $ (q( 0-00 TOTAL POSTAGE PROVIDED: $_ AFFIDAVIT OF O ERSHIP See attached Property Rights Acquisition Plan- property iqht-, will hp ohtainpd prior A-A pGp{�tructl on. ',yt,y,p S y j} declare that I am (plea rtyttWllil` % the owner of the property involved in this application, Mthe authorize representative to act for the property owner (please attar06p fF(8 avth ation), and that the foregoing statements and answers ein contained and the information herewith submitted are in all respects� Wreel-tj6 J*p st of my knowledge and belief. A(��Q ' - :'AE�TFJ!I�TjT ub�Rt f aId sworn to before me,a Notary Public.in and for Z,14 (Name of Owner/Representative) M :theptat4cf Wangtdp residing at y� the ta DA;bF 06nature of Owne 'Representative) �($i snT otary Public) COMPENSATION AGREEMENT Should this application require City staff time in excess of the basic time frame sl�established by City of Renton Ordinance#4322, 1 hereby agree to compensate the City of Renton for any and all extra labor and nonlabor cc accomplish accomplish the review and processing of this land use application. ♦��,,,ORE$ ^_ �% 4%. �SsioNFF F� R, /WAt-d ,J 5�C hsAk 0:��� ATTtk'.-,Qibscribed and sworn to before me,a Nc,-:ry Public.in and for (Print Na e) — V /VQTq/4at 15 a'shington residing at p,''hisG day of t:� 19 Cle (Sig' ature) �' ----- Billing Address t�t� /n j!l faf/j�Nujt S `9 R-U n`,��������y�§` ,l of Notary Public) a ti LEGAL DESCRIPTION OF PROPERTY The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the Metro Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. H:DOCS:93-1 109:SSW:ps SW GRADY WAY TO SW 16TH STREET PEDESTRIAN TRAIL PROPERTY RIGHTS ACQUISITION PLAN The City of Renton is proposing to acquire a minimum 15-foot wide permanent easement along the west bank of Springbrook Creek between SW Grady Way and SW 16th Street. The purpose of the easement is to allow construction of a 12-foot wide asphalt trail for public use across the 1-405 corridor to connect with the public trails to the north of SW Grady Way and to the south of SW 16th Street. The plan for acquiring the needed property rights for the pedestrian trail is shown below. TASK DESCRIPTION ESTIMATED NO. COMPLETION DATE 1 Surveyor Services Contract. The City will execute a contract 1/94 with a surveyor from the City's approved annual consultants contract list. The surveyor will be responsible for preparing the legal descriptions and drawings needed for the property rights conveyance documents. 2 Research and Assessment. Preparation and review of 2/94 appraisal, title report, and hazardous assessment documents will be coordinated by the City Attorney, if required. 3 Conveyance Documents. Concurrently with Task 2 the City 3/94 Attorney will prepare the necessary legal documents for the property rights transfer. 4 Negotiations. The City Attorney will coordinate negotiations 5/94 with the grantors. If, in a reasonable amount of time, agreement cannot be reached upon a reasonable settlement, then negotiations will be halted and condemnation proceedings initiated. 5 Condemnation. The City Attorney will prepare the necessary 10/94 documents, obtain Council approval by ordinance of the condemnation, and carry out condemnation proceedings, if required. H:DOCS:93-1093:S S W:ps r n •. :CITK:OF FtENT.ON DEVELOP MENT.SERVICES:DIVISIO.N CERTIFICATION OF G SU.RROUNOIN PROPERTY{OWNERS.HIP Within 300 feet of:the subjecf'site ***FOR OFFICIAL USE ONLY**` PROJECT NAME: APPLICANT: APPLICATION NO(S): The following is a list of property owners within 300 feet of the subject site. The Development Services Division will notify these individuals of the proposed development. NAME ADDRESS ASSESSOR'S PARCEL NUMBER See attached. F ASSESSOR'S PARCEL NAME ADDRESS NUMBER t Certification Do73o.v , hereby certify that the above list(s) of adjacent property owners an their a resses were taken room the records of the King County Assessor as prescribed by �e(aF. , ES� 4� cif+ d and sworn to before me, aub •: kd for the State of Washington, • • r$s%iHV ,v on.the y6� -4 . ASH + ,n Signed: rYm�` For Office Use Only _ . CERTIFICATION FOR MAILING I; hereby certify thaf ribtice ofe pending aforementioned project` was mailed on ¢�' - to 6k listed adjacent'property owner as prescribed by law. ... . ATTEST: Subscribed and sworn to before:me a ` '�' ,"�.'�'" • ;n, "" "`` biic,-in a i�f forthe State of Washington "'' �Notary..0u residing at " on the day of -'� Signed Y_r`r MAIIAW REV 01/92 2423049004 2423049022 2423049026 'PUGET WESTERN INC BOEING COMPANY METRO ACCOUNTS PAYABLE 9515 NORTH CREEK PKWY#310 PO BOX 3707 M/S 1F-09 SORENTONPR-5432-50706-D50218 ;30THELL WA 98011 SEATTLE WA 98124 821 2ND AVE SEATTLE WA 98104 2423049048 2423049049 2423049050 BOEING COMPANY BOEING COMPANY BOEING COMPANY PO BOX 3707 M/S 1F-09 PO BOX 3707 M/S 1F-09 PO BOX 3707 M/S 1F-09 SEATTLE WA 98124 SEATTLE WA 98124 SEATTLE WA 98124 2423049053 2423049054 2423049056 METRO BROWN L M & MOODY D A LONGACRES JOINT VENTURE 821 SECOND AVE 13975 INTERURBAN AVE S 921 MIDDLE FORK RD EXCHANGE BUILDING SEATTLE WA 98168 ONALASKA WA 98570 SEATTLE WA 98104 2423049061 2423049066 2423049097 GUY CHARLES B CITY OF SEATTLE METRO 3101 SE 5TH 821 2ND AVE EXCHANGE BLDG SEATTLE/METRO RENTON WA 98055 SEATTLE WA 98104 821 2ND AVE SEATTLE WA 98104 2423049098 2423049104 2423049107 CITY OF RENTON PUGET SOUND POWER&LIGHT CO PUGET WESTERN INC 200 MILL AVE S PROPERTY TAX DEPT 19515 NORTH CREEK PRKWY STE RENTON WA 98055 PO BOX 90868 310 BELLEVUE WA 98009 BOTHELL WA 98011 2423049108 2423049110 2423049112 PUGET WESTERN INC PUGET SOUND POWER&LIGHT SEPANEN DAVID C+PATRICIA L 19515 NORTH CREEK PRKWY STE PROPERTY TAXES 16709 SE JONES RD 310 PO BOX 90868 RENTON WA 98058 BOTHELL WA 98011 BELLEVUE WA 98009 2423049124 2423049125 2423049126 MOEN RUTH A MUNICIPALITY OF METRO SEATT MUNICIPALITY OF METRO SEA 9709 3RD AVE N E 821 SECOND AVE M/S 94 821 SECOND AVE M/S 94 SEATTLE WA 98115 SEATTLE WA 98104 SEATTLE WA 98104 3340405300 3340406120 3340406125 GROUP HEALTH COOP/PUGET SND BITNEY DEAN CITY OF RENTON 521 WALL ST W+GROUWS,CHARLE CITY HALL SEATTLE WA 98121 108 FACTORY AVE N,STE 2 200 MILL AVE S RENTON WA 98055 RENTON WA 98055 3340406255 3340406261 3340406625 KING COUNTY MCLEOD SUSAN N CUMMINS NORTHWEST INC 500 KC ADMIN BLDG 41 SPINOSA 811 SW GRADY WAY SEATTLE WA 98104 LAKE OSWEGO OR 97035 RENTON WA 98057 3340407100 9188000125 9188000148 CASEY FAMILY PROGRAM PUGET SOUND POWER& LIGHT FIRST CITY WASHINGTON INC 2033 6TH AVE SUITE 1100 PROPERTY TAXES 700 5TH AVE STE 6000 SEATTLE WA 98121 PO BOX 90868 SEATTLE WA 98104 BELLEVUE WA 98009 1 CITY OF''RENTON" ENVIRONMENTAL CHECKLIST PURPOSE OF CHECKLIST: The State Environmental Policy Act (SEPA), Chapter 43.21 C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An Environmental Impact Statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help the agency decide whether an EIS is required. INSTRUCTIONS FOR APPLICANTS: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or"does not apply". Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. USE OF CHECKLIST FOR NONPROJECT PROPOSALS: Complete this checklist for nonproject proposals, even though questions may be answered "does not apply." IN ADDITION, complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). For nonproject actions (actions involving decisions on policies, plans and programs), the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposal," "proposer," and "affected geographic area," respectively. -1- SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET PROJECT NARRATIVE Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 PROJECT NARRATIVE Project name: Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street Size and location of the project: The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. I- 405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Exhibit C. The project area is approximately 3-1/4 acres. Current use of the project site and adjacent properties: The existing Springbrook Creek channel that flows through the project area is best defined as a medium utility use and with adoption of the Interim Zoning Code has become an existing non- conforming use. This reach is the only outlet for a 22 square mile tributary drainage area and canno be abandoned, but will remain in use. The new channel segment to be constructed with the proposed project, which is adjacent to and includes portions of the existing channel, will create additional medium utility use between the existing channel and the 1-405 Oakesdale Avenue SW underpass. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack site now being developed as the Boeing CSTC facilities, and slightly southeast of the METRO Wastewater Treatment Plant. The property in the project area to the north of 1-405 and west of the project channel is vacant land, as is the property south and east of SW 16th Street. A single family dwelling with horse pasture is to the west of the channel, south of 1-405, and north of SW 16th Street. Nature of the existing shoreline: The reach of Springbrook Creek within the project area is an open channel which drains approximately 22 square miles of pervious and impervious land area from Kent, Tukwila, King County, and Renton. Surface water runoff reaches Springbrook Creek from these areas by overland flow or from a system of culvert and open channel point discharges along its length. Springbrook Creek flows north to join the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. The entire project is within 200 feet of Springbrook Creek. Springbrook Creek, through the project area, is designated a Shoreline of the State by the Department of Ecology, which determined that the mean annual flow of the creek in the area of the project was equal to or greater than 20 cubic feet per second (cfs). The current Shoreline Master Program designation of the project reach is urban (1990 - SMP 5.04.03). The entire project area also lies within the 100-year floodway and 1 floodplain according to Federal Emergency Management Agency Flood Insurance Rate Map 530033C0453D dated September 29, 1989. The FEMA Flood Insurance Study September 29, 1989 regulatory base flood (100-year) water surface elevation in the reach is 16.4 feet NGVD at SW 16th Street. The existing Springbrook Creek channel, including the reach in the project area, has been extensively modified and disturbed by dredging and vegetation management activities performed by adjacent land owners and Drainage District No. 1 . In a June 1, 1989 inventory by SCS, the existing channel was noted to have open water approximately 15 to 20 foot wide with 2 to 3 feet of woody and herbaceous vegetation on each side of the channel. The existing channel under 1- 405, however, has been severely eroded by flood waters and disturbed by subsequent shoreline anchoring efforts by the Department of Transportation under 1-405. The significant channel erosion and sedimentation result in low quality fish habitat. A wetland inventory of the proposed project area was conducted on March 1, 1993. Eight sites were sampled and described. Only the southern 1-405 roadside drainage ditch was identified as a wetland using the m.ethods of the Corps of Engineer's 1987 Wetland Delineation Manual and the 1989 Federal Manual for Identifying and Delineating Jurisdictional Wetlands. Two delineation methods are required because Springbrook Creek through the project area is not only under local jurisdiction, as defined by the 1989 Manual, but is also subject to the jurisdiction of the Federal Clean Water Act, Section 404, administered by the Corps, as defined by 1987 Manual. The wetland (Wetland A) is linear in shape and approximately 0.01 acre in size per 100 lineal feet of ditch. Because of its size, type, location adjacent to 1-405, and history of disturbance the wetland is given a low quality, Category 3 rating according to the City's Wetlands Management Ordinance. Proposed construction dates and phasing: Construction is anticipated to extend from late May to mid-October 1994. A total of 95 working days is anticipated for the project as follows: Mobilization: 10 working days Construction: 80 working days Cleanup: 5 working days Any construction within the existing channel will be allowed to occur during the summer months of the Washington State Department of Fisheries "window" from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. The contractor will prepare a construction mitigation plan, outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. City of Renton approvals or permits needed for the project: Shoreline Substantial Development Permit Conditional Use Permit Fill and Grade Permit Fill and Grade License/Construction Permit Land Clearing and Tree Cutting Permit Variance Site Plan Approval 2 Existing improvements and project description: The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way; the SW Grady Way and 1-405 box culverts, the P-1 Channel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of .this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P- 1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide. The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the 1-405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Fill blocking the SW Grady Way box culvert would also be 3 removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey • some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Because of its limited access requirements and elevated grade access from 1-405 is not possible. SW Oakesdale Avenue drops below surrounding grade as it passes under 1-405 so access from this street is also not possible. Maintenance vehicle use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80 feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of . the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation Division in a planned study of the crossing alternatives. No views will be obstructed as a result of the proposed project, as the improvements are located within the channel area and are at or below adjacent top of bank grades. Purpose, type, and approximate quantities of grading proposed: A low flow channel will be constructed in the main channel, connecting with the low flow cells of the 1-405 and SW Grady Way box culverts. The low flow channel will have a 12-foot bottom width and 3 horizontal to 1 vertical side slopes. The overall top width of the low flow channel will be 27- feet. The main channel, including the low flow channel, averages 65-feet in width. To construct the proposed channel, the existing material necessary to achieve the proposed channel section subgrade will be removed. Subgrade is generally 1 .5-feet below the proposed finish grade, with a portion of the proposed channel directly adjacent to the Oakesdale Avenue SW underpass and underdrain system over excavated to 5-feet below the proposed finish grade to allow placement of a watertight PVC membrane. The underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, must be protected from the short-circuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. To prevent this piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the membrane will be connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This 4 increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. The use of sheet piling driven into the channel bottom to lengthen the flow path was also considered, but was not selected because the piling may reach refusal too soon to provide effective protection. The total amount of excavation is estimated to be 15,700 CY. A total of 3 1/2-feet of fill material will be placed on the membrane to achieve subgrade. To reach finish grade on a portion of the channel, including the low flow channel, a total of 1/2-foot of sandy filter material and 1-foot of clean, loose rip rap will be placed on the subgrade. Other areas of the channel not receiving rip rap that are subject to potential erosive flows will be brought to finish grade with fill material and overlain with an excelsior blanket. This will protect the exposed soil and allow vegetation to become established to further protect against erosion. Excavation is also proposed to allow for placement of concrete wing walls on the west side of the I- 405 and SW Grady Way box culverts and a gabion wall north of the SW 16th Street bridge. The west side of the proposed and existing channel between SW Grady Way and 1-405 will be graded to a stable 2 horizontal to 1 vertical slope and a 1-foot depth of rip rap on 1/2-foot depth of filter material will be placed to protect against future erosive flows. The total estimated quantity of fill for the channel work is 8100 CY, including filter material and rip rap. Construction of the pedestrian trail shown in the plans will require an estimated 500 CY of fill to achieve subgrade. Fill material will be well graded sand to silty sand. The material will be from an approved gravel mining site and will arrive to the site via 1-405, SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. The specific source of the fill material and haul route is unknown at this time, but will be provided as a part of the final construction management plan, and will be submitted for approval to the City Development Services Division. Special plans to be prepared: Erosion control plan. Before any construction activity occurs, a pre-construction meeting with the contractor will be held with the project engineer and the City. Prior to the meeting, the contractor shall provide to the City and Engineer an erosion control plan for review and approval. The plan shall be based on the King County Surface Water Design Manual, as adopted by the City of Renton, proper construction practices, and any measures detailed in the contract plans and specifications. The contractor will also be responsible for addressing any state and federal permit conditions required for the project. All required sedimentation/erosion control facilities must be constructed and in operation prior to clearing and/or other construction to minimize discharge of sediment laden water from the project site. The implementation, maintenance, replacement, and additions to control facilities will be the responsibility of the contractor. As construction progresses and unexpected or seasonal conditions dictate, the contractor shall anticipate that more erosion and sedimentation control facilities will be necessary to insure complete siltation control on the project site. It shall be the obligation and responsibility of the contractor to revise or modify the erosion control facilities to meet any new conditions that may be created by construction activities and to provide additional facilities, over and above minimum requirements, as may be needed to protect adjacent properties and water quality of the receiving drainage system. 5 Construction mitigation plan. Prior to the preconstruction meeting the contractor shall also provide to the City and Engineer a construction mitigation plan outlining the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. Dewatering plan. Ground water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Geotechnical reports for other projects in the project area describe ground water levels at relatively shallow depths. Because of potentially high ground water conditions the contractor for the proposed project will be required to determine if conditions at the time of construction are low enough to allow construction. If not, the contractor will be required to construct well points at strategic locations in the project area to draw down the water table sufficiently. Before any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. The amount of ground water to be withdrawn is a function of the soil conditions, water table elevation, required drawdown, and wellpoint location and depth. Therefore, the number of wellpoints and the amount of groundwater that will be withdrawn cannot be estimated at this time. Springbrook Creek bypass plan. Springbrook Creek will be routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. This is necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. The sequence and timing of the any bypass is to be contractor determined, subject to the review of the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. It is anticipated that construction of the channel north and south of 1-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the weather conditions at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. Special site features: The site or portions of the site have been classified as within or containing the following environmentally sensitive areas: 100-year floodplain, wetlands and streams, surficial aquifer susceptibility, and seismic hazards. Seismic hazards. The City of Renton has mapped the Green River Valley area as a seismic hazard, due to the liquefaction potential of the unconsolidated sands present in the Valley soil profile. Even without the proposed project having been constructed, the adjacent structures are subject to liquefaction induced settlement. However, these structures were designed to accommodate the proposed channel improvement. The construction of the project is therefore not anticipated to impose unanticipated risks to structures in the project area due to seismic ground movement and acceleration. The 1-405 bridges in the vicinity are constructed on piling and other structures are founded on broad footings to reduce the risk of settlement due to liquefaction. 6 Surficia/aquifer susceptibility. Although the project is within an area designated as having surficial aquifer susceptibility, it is outside of the City's aquifer protection zones and is not regulated by the City's aquifer protection ordinance. No significant increase in groundwater recharge is expected because the membrane proposed for installation next to SW Oakesdale Avenue is an effective barrier. H:DOCS:94-006:SSW:ps 7 SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET LAND CLEARING AND TREE CUTTING ORDINANCE VARIANCE JUSTIFICATION Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 Land Clearing and Tree Cutting Ordinance Variance Justification LAND CLEARING AND TREE CUTTING ORDINANCE VARIANCE JUSTIFICATION A. Justify that the applicant suffers undue hardship and the variance is necessary because of special circumstances applicable to subject property, including size, shape, topography, and location or surroundings of the subject property, and the strict application of the Building & Zoning Code is found to deprive subject property owner of rights and privileges enjoyed by other property owners in the vicinity and under identical classification. The proposed project includes work within 25 feet of the ordinary high water mark of a segment of Springbrook Creek from SW 16th Street to SW Grady Way. However, Section 4-9-5.D of the Land Clearing and Tree Cutting Ordinance states, "No tree cutting or land clearing is permitted within twenty five feet (25') of any shoreline area, within twenty five feet (25') of the ordinary high water mark of creeks, in a wetlands area, or on parcels where the predominant slope or individual slope is in excess of forty percent (40%) except enhancement activities." The proposed project does not qualify as an exempt enhancement activity according to the definition in Section 4-9-3 of the Ordinance. Therefore, a variance is requested because portions of the project are within 25 feet of the sensitive areas listed in Section 4-9-5.D. The project suffers undue hardship because strict application of the Ordinance would prohibit any regional flood control project involving work within a creek, wetland, or shoreline needed to mitigate the expected cumulative effects of increased runoff volumes or flows to that sensitive area. These cumulative effects are primarily due to increases in impervious land area through development upstream, which if unmitigated, will increase flooding, erosion, sedimentation, and other related environmental impacts and costs in downstream streams and wetlands. Similarly, the Ordinance would prohibit regrading of a segment of the existing stream bank within the proposed project area that has been eroded to a near vertical slope and is therefore unstable. Strict application of the Ordinance, therefore, inhibits management of the City's stormwater and related environmental resources necessary to promote the public health, safety, and general welfare of the citizens of Renton. B. Justify that the granting of the variance will not be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity and zone in which subject property is situated. Soil erosion could occur in connection with variance approval, since the entire area of the channel and pedestrian trail construction will be cleared of existing vegetation. Shoreline anchoring provided by the riparian trees, shrubs, and grasses will be temporarily lost. Erosion that could occur during rain and/or wind storms during the construction phase of the project will be minimized and is not expected to be materially detrimental with mitigation. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. 1 Land Clearing and Tree Cutting Ordinance Variance Justification The riparian vegetation to be removed under the authority of the variance is not diverse habitat or of significant structure. The trees to be removed are small and, at generally 6" in diameter, are the minimum size regulated under the ordinance. Removal of the trees and other riparian vegetation will be mitigated by providing surface cover protection to disturbed areas immediately upon achieving final grade or as conditions warrant. The project design includes a combination of plantings, rip rap, and erosion control blankets to minimize the erosion potential during and after construction. The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and washpads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. The project does not propose any improvement in the floodway that will increase the risk of flooding upstream of the project area. Instead the project removes restrictions from the floodway and reduces the risk. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of an existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. Due to restricted access requirements and the elevated grade of 1-405, vehicular access to the project site from 1-405 is not possible. Access to any portion of the project area from SW Oakesdale Avenue is also not possible because it drops more than 12 feet below surrounding grade as it passes under 1-405. Access is not possible from SW 16th Street or SW Grady Way to the project area east of the existing channel because of the depth and sensitive nature of the existing channel would restrict crossing opportunities. Because of this limited access to the project area, the proposed channel utilizes land area which is of no commercial use, but can be enhanced to provide a riparian corridor for fish and wildlife habitat. Use of the land within the project area is also limited by its proximity to the existing Springbrook Creek channel and the associated setback provisions of City Codes for any development along that channel. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicle use is expected to be infrequent and so the waste material associated with vehicular use will not be significant. Vegetation removed for the trail construction will be restored as nearly as practicable to original condition as found immediately before commencement of the work. The potential for soil erosion associated with any clearing of vegetation for the trail as authorized by the requested variance will be minimized and mitigated as noted above for the channel portion of the project. 2 Land Clearing and Tree Cutting Ordinance Variance Justification • C. Justify that approval shall not constitute a grant of special privilege inconsistent with the limitation upon uses of other properties in the vicinity and zone in which the subject property is situated. Approval does not constitute a grant of special privilege because others may include a regional flood control improvement use or facility in a project proposal. D. Justify that the approval as determined by the Hearing Examiner is a minimum variance that will accomplish the desired purpose. Granting of the variance provides relief from the provisions of Section 4-9-5.D that would prohibit land clearing and tree cutting associated with the proposed project. Other provisions of the Ordinance still apply. H:DOCS:93-007:SSW:ps 3 SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET ADMINISTRATIVE CONDITIONAL USE REQUEST JUSTIFICATION Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 Administrative Conditional Use Request Justification ADMINISTRATIVE CONDITIONAL USE REQUEST JUSTIFICATION The use of the area effected by the proposed project is best defined as "medium utility" because the channel improvement will serve to convey storm drainage from the sub-area of the City within the Black River Basin. Portions of the project site are zoned Medium Industrial (IM) and Commercial Office (CO). According to the Interim Zoning Code (RMC 4-31), an administrative conditional use is required for a medium utility use in the IM (RMC 4-31-11.2) and CO (RMC 4-31-16) zones. It is recommended that an administrative conditional use be granted for the reasons following. A. Comprehensive Plan: The proposed use shaf/ be compatible with the general purpose, goals, objectives, and standards of the comprehensive plan, the zoning ordinance, and any other plan, program, map, or ordinance of the City of Renton. 1. Comprehensive Plan. The project is consistent with the overall goal of Chapter 8, Environment, of the Interim Land Use Element of the Comprehensive Plan (Renton, 1993), "Continued protection of Renton's natural systems, natural beauty, and environmental quality." The project will provide increased floodwater conveyance through the existing reach that is too narrow for adequate floodwater passage. The existing channel is also too confined and may not be widened without undermining the existing pile supports for the 1-405 bridge, which are not spaced sufficiently far apart to allow the existing channel under the bridge to be enlarged. An additional 4 acre-feet of floodwater sto.rage,will be provided. These benefits add to the level of flood protection provided upstream of the project area. The project is designed for multiple use and benefit with the inclusion of elements such as: 1) fish and wildlife habitat plantings and structures, 2) low flow fish passage channel, 3) regrading and armoring of existing severely eroded stream banks, 4) high flow conveyance and storage within the new and existing channels for increased flood protection, 5) preservation of the existing channel for off-stream fish and wildlife habitat, and 6) inclusion of a pedestrian trail link for recreational opportunities and public access to the shoreline. Because of these multiple uses and benefits, the project is also consistent with many of the objectives and policies of Chapter 8, Environment, of the Interim Land Use Element. Policy EN-4.1: "Manage water resources for multiple uses including recreation, fish and wildlife, flood protection, erosion control, water supply, energy production, and open space"(emphasis supplied). Policy EN-5.2: "Degraded channels and banks should be rehabilitated by public programs and new development" (emphasis supplied). Policy EN-8.1 : "Maintain and enhance natural drainage systems to protect water quality, reduce public costs, and prevent environmental degradation." Policy EN-8.2: "Preserve natural surface water storage sites that help regulate service flows and recharge groundwater" (emphasis supplied). Objective EN-9.0: "Provide a storm and surface water control and drainage system capable of preventing threats to life, property and public safety during a 100 year flooding event." 1 Administrative Conditional Use Request Justification Policy EN-9.4: "Manage the cumulative effects of storm water though a combination of engineering and preservation of natural systems." Objective EN-10.0: "Provide for, and work toward, a regional approach to stormwater management programs." The project is a joint effort of the City of Renton and the U.S.D.A. Soil Conservation Service (SCS). The project is approximately 75% funded by SCS through the Watershed Protection and Flood Protection Act (Public Law 566). Objective EN-14.0: "Protect and enhance wildlife habitat through the City." Policy EN-17.6: "Incorporate design elements which preserve and enhance the natural drainage system into developments in an effort to control erosion and sedimentation." 2. Zoning Ordinance. The project is also compatible with applicable development standards within the IM and CO Zones. a. Landscaping. The wildlife planting proposed with the project covers a 3200 square foot area, in satisfaction of the 2% landscaping requirement in the Development Standards section of the IM zone (RMC 4-31-11 .2.D). b. Sensitive Areas. The project is consistent with the applicable requirements of the Flood Hazards and Landscaping sections of the Zoning Ordinance as follows: 1) Flood Hazards (RMC 4-31-31). "Encroachments...and other development...shall not result in any increase in flood levels during the occurrence of the base flood discharge" (Section G3a). The project will not only meet this requirement, but exceed it, by reducing the flood levels upstream of the project. 2) Landscaping (RMC 4-31-34). "Any development in the Green River Valley shall provide a minimum of two percent (2%) of the total site for landscaping suitable to wildlife habitat" (Section F2). The wildlife planting area proposed for the project meets this 2% requirement. "The faces of cut and fill slopes shall be developed and maintained to control against erosion. This control may consist of effective planting. Where necessary...rip rap or other devices or methods shall be employed..." (Section F4). Before any construction activity occurs, a pre-construction meeting with the contractor will be held with the project engineer and the City. Prior to the meeting, the contractor shall provide to the City and Engineer an erosion control plan for review and approval. The plan shall be based on the King County Surface Water Design Manual, as adopted by the City of Renton, proper construction practices, and any measures detailed in the contract plans and specifications. The contractor will also be responsible for addressing any state and federal permit conditions required for the project. Prior to the preconstruction meeting the contractor shall also provide to the City and Engineer a construction mitigation plan outlining the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul 2 Administrative Conditional Use Request Justification route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. All required sedimentation/erosion control facilities must be constructed and in operation prior to clearing and/or other construction to minimize discharge of sediment laden water from the project site. The implementation, maintenance, replacement, and additions to control facilities will be the responsibility of the contractor, subject to the approval of the City and project engineer. Any construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. As noted above the contractor will prepare a construction mitigation plan outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. A 1-foot deep rock rip rap protective layer will be placed over disturbed areas under and adjacent to the SW 16th street bridge, the low flow channel area, and a portion of the west bank of the channel between 1-405 and SW Grady Way. The rip rap on the west bank area will be loosely placed, covered with topsoil, and seeded. A 0.5-foot deep layer of filter material will be placed under the rip rap to prevent washing of any finer material from the underlying soil. Wire mesh gabions will be placed along a portion of the west bank just north of the SW 16th Street bridge to protect against erosive flows. A layer of filter material will be placed behind the gabions to prevent washing of finer material from the protected bank. Disturbed areas will be seeded immediately following construction. Seeding shall be started as soon as definable segments of the excavated channel are completed as determined by the Engineer. Permanent seed mixtures shall be applied between April 1 to October 15. Winter seeding shall be applied outside the permanent seeding dates as needed, and followed with permanent seeding the next spring as approved by the Engineer. Following permanent seeding, a portion of the area outside the low flow channel that was disturbed during construction will be covered by an excelsior blanket for erosion control and to aid vegetative establishment. As construction progresses and unexpected or seasonal conditions dictate, the contractor shall anticipate that more erosion and sedimentation control facilities will be necessary to insure complete siltation control on the project site. It shall be the obligation and responsibility of the contractor to revise or modify the erosion control facilities to meet any new conditions that may be created by construction activities and to provide additional facilities, over and above minimum requirements, as may be,needed to protect adjacent properties and water quality of the receiving drainage system. 3. Shoreline Master Program. The multiple uses and benefits included with the proposed project noted in Section Al above are also consistent with the following goals and policies of the Shoreline Master Program. 3 Administrative Conditional Use Request Justification "Preference should be given to those uses or activities which enhance the natural amenities of the shorelines and which depend on a shorelines location or provide public access to the shorelines" (Section 4.01 .02.A.2). The project must be constructed at the proposed location because the existing 1-405, SW Grady Way, SW 16th Street, and Oakesdale Avenue SW streets confine Springbrook Creek within the project area to a narrow, defined corridor. An alternative location for the new channel is not available outside of the proposed project area. Also, all downstream improvements and major structures necessary for the proposed project have already been permitted and constructed. The pedestrian trail component of the project provides public access to the shoreline. "Existing natural resources should be conserved" (Section 4.02.02.A). The existing channel under 1-405 will be preserved to provide off-stream fish and wildlife habitat. The channel will also provide 4 acre-feet of additional flood water storage, as well as additional conveyance capacity. The plantings and structural features described in Section Al above also further implement this policy. "The City of Renton should take aggressive action with responsible governmental agencies to assure that the discharges from all drainage basins are considered an integral part of shoreline planning" (Section 4.02.02.C). The proposed project will be constructed with the assistance of SCS and is an essential element of a regional system of storm drainage facilities that convey basin discharges and provide flood control protection to the public. "Increase public accessibility to shorelines, and preserve and improve the natural amenities" (Section 4.04.01). "Pedestrian and bicycle pathways...should be developed" (Section 4.06.02.C). The pedestrian trail will provide public access to the shoreline in the project area. 4. City of Renton Master Trails Plan. "Address 'micro' level trails and fill in gaps in existing trail patterns where appropriate" (Policy 7). The project proposes a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south. This will complete a missing link segment of the Springbrook Valley Trail identified in the Master Trails Plan. B. Community Need. There shall be a community need for the proposed use at the proposed location. In the determination of community need, the Administrator shall consider the following factors among all other relevant information: 1. The proposed location shall not result in either the detrimental over-concentration of a particular use within the City or within the immediate area of the proposed use. The existing Springbrook Creek system is linear in shape and the land area currently subject to its use will not be significantly increased by the project or result in over-concentration of the use. The additional medium utility use to be provided by the proposed project is necessary to provide increased flood control protection to the public. 2. That the proposed location is suited for the proposed use. The existing Springbrook Creek channel that flows through the project area is best defined as a medium utility and with adoption of the Interim Zoning Code has become an existing non- conforming use. This reach is the only outlet for a 22 square mile tributary drainage area and 4 Administrative Conditional Use Request Justification cannot be abandoned, but will remain in use. The new channel segment to be constructed with the proposed project, which is adjacent to and includes portions of the existing channel, will create additional medium utility use between the existing channel and the 1-405 Oakesdale Avenue SW underpass. The new channel utilizes a narrow strip of land area, which by its location (lack of access) and zoning designation (setback requirements) is of no commercial or industrial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. C. Effect on Adjacent Properties: The proposed use at the proposed location shall not result in substantial or undue adverse effects on adjacent property. The proposed project is a regional flood control improvement designed to increase the level of flood control protection currently provided by the existing channel for all property upstream of the project reach. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project utilizes land area, which by its location and zoning designation, is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities consistent with the Shoreline Master Program goals and policies. The project increases the public accessibility to the shoreline, but preserves and improves the existing amenities. Acquisition of a permanent easement from adjacent property owners for the trail is proposed to secure the necessary rights to allow public access. A reasonable settlement with the property owners for the trail easement rights will be made. H:DOCS:94-005:SSW:ps 5 F SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET STORM DRAINAGE REPORT Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 A. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET The TIR worksheet for the project is attached (Attachment 1). B. PROJECT SUMMARY The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. I- 405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Attachment 3. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way, the SW Grady Way and 1-405 box culverts, the P-1 Channel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Attachment 2), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P- 1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. 1 The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide. The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the 1-405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Upland fill blocking the SW Grady Way box culvert would also be removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicles use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80 feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation Division in a planned study of the crossing alternatives. The pedestrian trail will cross the south 1-405 roadside ditch which conveys runoff from a 11.3 acre drainage basin situated west of Springbrook Creek, north of SW 16th Street, and south of SW Grady Way (Attachment 4). A culvert sized to pass the 100-year, 24-hour design storm (see Section H) will be installed to enable the pedestrian trail to cross the ditch. 2 The findings of this drainage report are valid for a 12-foot wide pedestrian trail from SW Grady Way to SW 16th Street regardless of the alignment selected by the Transportation Division, provided it generally follows along the existing channel of Springbrook Creek. C. EXISTING AND PROPOSED DRAINAGE FEATURES The existing and proposed drainage features are described in Section B. D. CORE AND SPECIAL REQUIREMENTS Core Requirement #1. Discharge at the naturallocation. The discharge location will remain unaltered by the project. Core Requirement #2. Off-site Analysis Level 1. The project is adjacent to, and includes portions of, an existing reach of Springbrook Creek that flows north. Springbrook Creek joins the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. No problems associated with high flows/flooding are apparent in immediate area of the existing Springbrook Creek channel and Black River Pump Station forebay improvements downstream of the project area. Within the project area, a portion of the west bank of the existing channel north of I- 405 has been eroded to a near vertical slope and is therefore unstable. This area will be graded to a more stable 2 horizontal to 1 vertical slope and protected with rip rap and vegetation. Studies have shown that Springbrook Creek has poorer water quality than many other urban streams in the area (Metro, 1990; City of Renton, 1993). Sediment deposits downstream of the project area appear to be accumulating. Sediment accumulations reduces available conveyance capacity and may eventually become a problem over time. Core Requirement #3. Runoff Control The 0.03 cfs increase in pre-developed runoff condition for the 100-year, 24-hour design storm due to the project is less than the 0.5 cfs threshold increase for exemption from runoff control requirements. Therefore peak rate runoff control (detention) is not required as part of the project. The increase in runoff volume of 486 cf is insignificant compared to the 4 acre-feet increase in storage that the project will provide. See Attachment 5. Core Requirement #4. Conveyance System. Construction of the proposed project will reduce head loss in the project reach which will result in lowering the base flood water surface profile of the upstream system. The project will also allow higher flows to pass through the project reach to the downstream system and more fully utilize the capacity for which the downstream improvements were designed (R. W. Beck, 1991). 3 Core Requirement #5. Erosion/Sedimentation Control Plan. The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and wash pads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. Special Requirements #1-#12. None of the special requirements apply to this project. E. On-site Detention Design Does not apply because the project is exempt from Core Requirement #3, Peak Rate Runoff Control. F. Biofiltration Design Does not apply because the project does not propose to construction more than 5,000 square feet of new impervious surface subject to normal vehicular use. G. Wet Pond Design Does not apply because the project will construct less than 1 acre of new impervious area. H. Conveyance Velocity Calculations The full flow velocity of the 24" concrete culvert selected for the south 1-405 roadside ditch for the 100-year, 24-hour design storm of 9.40 cfs is 3.0 fps. See Section I for the culvert sizing. I. Conveyance Capacity Calculations The objective of the culvert design is to minimize the head loss through the culvert for the 100- year, 24-hour design storm, which for the tributary basin of 11 .31 acres was calculated to produce a peak rate runoff of 9.40 cfs in the post-project condition (Attachment 5). Because the ditch is deep at the culvert location, a 60' length is required in order for the ends of the culvert to protrude from the fill slopes extending from the grade of the proposed trail. An inlet invert elevation of 6 feet and an outlet invert elevation of 4 feet (NGVD 1929) was assumed based on the profile of the ditch invert. The culvert capacity was based on outlet control with the 100-year tailwater elevation of Springbrook Creek of 13 feet (R. W. Beck, 1992) and the sizing completed utilizing the nomograph included as Attachment 6. A 24" culvert was selected because its ability to conduct the design flow of 9.40 cfs, minimize any headloss, and maintain a 3 fps full flow velocity. See Section H for the full flow velocity check. 4 J. Level One Downstream Analysis See Section D, Core Requirement #2. List of Attachments Attachment 1. Technical Information Report (TIR) Worksheet Attachment 2. Watershed Map Attachment 3. Project Vicinity Map. Attachment 4. South 1-405 Roadside Ditch Tributary Basin Map Attachment 5. Peak Rate Runoff Calculations Attachment 6. Pipe Sizing Nomograph References Metro. 1990. Quality of local lakes and streams, status reports for 1988-1989. (Publication 167, Revision A.) Water Resources Section. Water Pollution Control Department. Seattle, WA. R. W. Beck and Associates. 1991. East Side Green River watershed plan, current condition document. Seattle, WA. Prepared for City of Renton, Renton, WA. 1992. East Side Green River watershed plan, hydraulic analysis report. Seattle, WA. Prepared for City of Renton, Renton, WA. Renton. 1993. Black River Basin water quality management plan. Prepared by R. W. Beck and Associates and Herrera Environmental Consultants in association with Jones & Stokes Associates, Inc. Seattle, WA. H:DOCS:94-004:SSW:ps 5 Attachment 1 Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PROJECTPART 1 OWNER AND PART 2 PROJECT • • PROJECT ENGINEER AND DESCRIPTION Project Owner C I'4 a(" "Y✓Tu A) Project Names P)" Ckt E k/?-% C k A,*6 c Address '00 m i,,; F..��,r�rr ` 1 u7rr Location Ire,f�'-o".4^C-"rl Phone 20G- 2-7-) - 55y7 Township 3 Project Engineer SOIL Range Section Company Project Size 3. S AC Address Phone Upstream Drainage Basin Size ° 2 aO AC PART 3 TYPEOF PERMIT APPLICATIONOTHER Subdivision 0 DOF/G HPA ® Shoreline Management E-1 Short Subdivision © COE 404 Rockery ® Grading 0 DOE Dam Safety Structural Vaufts E:J Commercial FEMA Floodplain Other 0 Other ® COE Wetlands ® HPA COMMUNITYPARTS SITE r DRAINAGE _ Community Drainage Basin /ICAS' PARTS SITE CHARACTERISTICS River ® Floodplain ® Stream 0 Wetlands Criiicai Stream Reach ID Seeps/Springs 0 Depressions/Swales © High Groundwater Table Lake 0 Groundwater Recharge 0 Steep Slopes Other F-1 Lakeside/Erosion Hazard SOILSPART 7 Soil Type Slopes Erosion Potential Erosive Velocities (J(LKAw� f A�9 CebN(�AI�u r'G�� 7- Additional Sheets Attatched 1/90 Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET LIMITATIONSPART 8 DEVELOPMENT REFERENCE LIMITATIOWSITE CONSTRAINT 0 Ch.4-Downstream Analysis 0 0 0 0 a Additional Sheets Attatched -PARM;AESC*V1E0UIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION ® Sedimentation Facilities ® Stabilize Exposed Surface ® Stabilized Construction Entrance � Remove and Restore Temporary ESC Facilities ® Perimeter Runoff Control ® Clean and Remove All Silt and Debris ® Clearing and Grading Restrictions © Ensure Operation of Permanent Facilities © Cover Practices Flag Limits of NGPES ® Construction Sequence Other Q Other 0 Grass Lined Channel 0 Tank 0 Infiltration Method of Analysis 0 Pipe System 0 Vault 0 Depression S;U4! L� Open Channel 0 Energy Dissapator 0 Flow Dispersal Compensation/Mitigation ® 0 Dry Pond Wetland 0 Waiver of Eliminated Site Storage 0 Wet Pond ® Stream Regional Detention Brief Description of System Operation Additional Sheets Attatched Reference Facility Lunation requireRAL ANALYSIS •' C] Drainage Easement ® Access Easement C] Cast in Place Vault 0 Other 0 Native Growth protection Easement 21 Retaining Wall 0 Tract 0 Rockery>4'High 0 Structural on Steep Slope ® Other 71or civil engineer under my supervision have visited the site.Actual conditions as observed were incorporated into this worksheet and thechments. To the best of my knowledge the Information provided 1 tZ L here is accurate. 1/90 RAD01007 ...•..�~ Black River j—Watershed King County Boundary Water Quality �''�� % ,,...., Management Plan • J Study Area -�.•..•- •• Its *: Gee - 1 ••�....-> •�'•) • �`r Panther Lake Qo �'• 05 King ng Count Garrison •.•' Renton Creek L�.r I Renton t Grids .�•� panther Creek We' King County Upper , ----._ Sprang roo. ..-• • Valley rea N 167 Kent � �S rin brook reek i i4 vEastValle Road , i Springbrook _ ' Creek i e to Nill 67 u W1 6 C eek r. • � Ke N Block River ' ee nt 81 , Pump Station Tukhllo L.-J N Kent , Tukwila ' Kent Lagoons 1-5 _^ EAST SIDE GREEN RIVER WATERSHED Nrs SouRct RW BECK ANDAssoaATES A S lD rr N Attachment 3 ' N Pun,P s1 AT/ov RENTON FOP- BAY z `------ B�d=R/- South Renton Subbasin r— Pumping , cagxESp Station � ALFc �M Er Ro� •\, GRADy WA E Basin Boundary a Rolling` •`• sw pan sL Hills Drain i Rolling Hills t o If Subbasin 1 �� P-9 Channel - ,m a � 181 > Panther Creek Wetland Valley Subbasin i Panther Creek Subbasin 167 �F Is-wawa , LEGEND j ------ Stream/Drainage Channel �,'� SPringbrook Springs ------------- Storm Drain Pi P ro � � ' Subbasin d Subbasin Boundary $1 0 1000 2000 3000 SCALE IN FEET SouR cE :HF2RF R 1 .vvl2o�✓�n F.✓TAt Black River Basin Water Quality Management Plan Gsr 1i;u1x• f;111� • �uvA F'- ' t —rs. •. Qi t � �yy r . iM HIM � . Tiff %cam �+.�;��i1lp` ► \ ` `\ ��_� F �♦ •►�� �t_ r �r Attachment 5 Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street PRE-DEVELOPMENT AREA WEIGHTED RUNOFF COEFFICIENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN ................................ .:..:.. . .::.: :.:.:.:V. _:::::::::::.....:.:.:.::::.: :::::::::::::::.:::::::. :::.::::::::g:: .::::::..:::::::::: :::::.:::::::::.::: <;: rt€t :::: ::::>::>:�Grou ii€> :< tttmier' i:.;:; .: :.:: .:..,A........... _ ............................................................. Ur D 98 Pavements, Roofs 5.64 50% 48.9 Ur D 91 Compact Gravel 0.21 2% 1.7 Ur D 90 Landscape,Grass 5.46 48% 43.5 POST-DEVELOPMENT AREA WEIGHTED RUNOFF COEFFICIENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN :::::.:::H fi a t g:::..::.:::::::::::: .::. .::::............::..::::::::: ::::::::::::.:::::::::::::.:::�t[::::�. .::.:::.::::::::::::.::� ::.::::::::: >;::: Ilrer>: ::: :::>:::::::>:::::>:::::: . > tre.Mcirlter:.>; Ur D 98 Pavements, Roofs 5.80 51% 50.3 Ur D 91 Compact Gravel 0.21 2% 1.7 Ur D 90 Landscape,Grass 5.30 47% 42.2 HYDROGRAPH SUMMARY PRE-DEVELOPMENT AND POST-DEVELOPMENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN ... .... ..... . ......... X r: L1#'......................................... .... U: t#31M� `::>:><:>'::>::>::>:: 3.. ::..:. ::..: 4TE1 ::z'. >«::>:<>::>:> >:><: Pre-Development 9.37 133683 Post-Development 9.40 133197 .:. Difference>�I�:: ange :.> 3, .: *Q :::> ....... (ar4. Jo :::>::::>::::>::,: :::::::::::::><><::.: Notes: 1. Soil groups determined from USDA SCS Soil Survey, King County Area, Washington, 1973. 2. Hydrologic groups determined from KCSWM Manual Figure 3.5.2.A. 3. Curve numbers determined from KCSWDM Table 3.5.2B. 4. Land use descriptions from City of Renton aerial photographs and Boeing CSTC drawings. �TikcHN,E,�r - C.oN7i•,,v�0 If 9 D 2�C,{t A PH ourPyi' ion-y2l zy- 1-;/Z 570 - p -o�ubt,o,°nV�bNT HhOkaGPAPP 5-Wr,r,AAJ W W W S.C.S. TYPE-lA RAINFALL DISTRIBUTION =i i ENTER: FREQ(YEAR) , DURATION(HOUR), PRECIP(INCHES) c o o 100,24,3.90 �r ---------------------------------------------------------------------- a a a S.C.S. TYPE-IA DISTRIBUTION ******************** NN Ir ********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. ********* C4 N H all —————————————————————————————————————————————————————————————————————— ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 5.67,90.04,5.64,98,9.5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 11.3 5.7 90.0 5.6 98.0 9.5 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) 9.37 7.83 133197 {DU- y/t/ zy NR. ST0In, FLsi- �v�cay`�ENT Ah0/4 P-APR 5v AA t, S.C.S. TYPE-lA RAINFALL DISTRIBUTION ENTER: FREQ(YEAR), DURATION(HOUR), PRECIP(INCHES) 100,24,3.90 ---------------------------------------------------------------------- ******************** S.C.S. TYPE-lA DISTRIBUTION ******************** ********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. ********* ---------------------------------------------------------------------- ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 5.51,90.04,5.80,98,9.5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 11.3 5.5 90.0 5.8 98.0 9.5 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) 9.40 7.83 133683 _ /rrA c 14 0& S Lu+�IT{Nv��p TI M 6 OF Gehl C4-,-J rPCA i)dYJ A$SvvwE 2.06' SN40'6fi F1. W + I000 YWfjt -,1TfjT J--t.ew CA,A) a- 2,04 /rJTC(I,'17T9,Jr&WA A V!N Sa o. 0'L L,Ir / ✓S. = a. 01 50 - 0. 61 / kc = 1 O, 01- P7#r W W W W maW xxx %A in 0 coo /A(,Cfj L oT-t T���6 L T!rv4-S �r era o.B r o•3 S�GYI^�fi✓ A 7 Z O .'1: hs O_ ! o.S o.ry o. errs �i S 2 (O" oL I 4 �F 56�,�,ti,✓T Y? r _ j cao z ? (�p1CTG.s 2�kJ"oz U" I� SN'�Mf,r✓r L _ �oc) = 1 Z M 1Aj L a kSa fl. iG T! ? i 2 `, isTr����ME.N KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL r FIGURE 4.3.5E HEAD FOR CULVERTS (PIPE W/"n" =0.012), FLOWING FULL WITH OUTLET CONTROL 2000 T— — " MWI =_ —� ho .4 _ ur Slope So—. 1000 a Z SUSMERGEO OUTLET CULVERT FLOWING FULL J .5 NW.N♦Ao—LSo 800 120 For 09t1411 CFO" "Of submsrQsd.camput* N by .6 IMlhods described M theddsipp procedure Soo108 8 500 96 1.0 400 84 / 300 72 / 66 � 6 200 60 FY� b O �Fy W 2 sn / `o cr9 U. IL 54 / z 2 N 0.48 / _ .110 00 ` LU 48— —- te.0 `00 = 3 0 100 z ---' oo 80 10/' 42 QOO 3 w 4 � / O _ 0 3 6 3p0 ao 5 N 60 50 H 3 3 A00 500 6 w 30 40 a 500 it 8 O 2 7 if •' 00 O 30 O T3 10 4 vlo 21 16 20 15 8 6 12 5 4 4.3.5-13 1/90 A. BACKGROUND 1. Name of proposed project, if applicable: Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street 2. Name of applicant: City of Renton Surface Water Utility 3. Address and phone number of applicant and contact person: Ronald J. Straka Staff Contact: City of Renton Surface Water Utility Scott Woodbury, Project Manager 200 Mill Avenue South City of Renton Surface Water Utility Renton, WA 98055 206-277-5547 4. Date checklist prepared: December 1993 5. Agency requesting checklist: City of Renton Planning/Building/Public Works Department 6. Proposed timing or schedule (including phasing, if applicable): Construction is proposed to occur in the summer of 1994. Any work within the channel of Springbrook Creek is proposed to be completed within the Washington State Department of Fisheries June 15-September 15 "fisheries window". 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No. This project is the final phase of a series of flood control improvements constructed north of SW 16th Street under the 1979 East Side Green River Watershed Plan Final Environmental Impact Statement and 1981 Amplification. An updated watershed plan and EIS are being prepared to define the scope and impact of future flood control improvements south of SW 16th Street. See Project Relationship with the Green River Watershed Plan (Exhibit A). 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Final Environmental Impact Statement_ USDA Soil Conservation Service. June 1979. Amplification of Final Environmental Impact Statement. USDA Soil Conversation Service. February 1981. Report of Geotechnical Investigation, Box Culvert, SW Grady Way, GeoEngineers, Inc. October 31, 1984. Geotechnical Engineering Evaluation for P-1 Channel - SR405 Box Culvert. Hong Consulting Engineers. July 17, 1986. Geotechnical Report, Oakesdale Avenue. CH2M Hill. September 1987. Report of Geotechnical Investigation, Proposed Box Culvert, SW 16th Street. GeoEngineers, Inc. May 25, 1988. Biological Assessment. USDA Soil Conservation Service. June 1, 1989. -2- East Side Green River Watershed Hydrologic Analysis. Northwest Hydraulic Consultants, Inc. December 1991. East Side Green River Watershed Plan Hydraulic Analysis Report. R.W. Beck and Associates. March 1992. City of Tukwila Nelson Place/McLeod/Boeing CSTC Storm Drainage Study Technical Report. HCW-L. December 29, 1992. Black River Water Quality Management Plan. R.W. Beck &Associates. May 1993. Wetlands Determination. USDA Soil Conservation Service. June 1, 1993, November 3, 1993, November 29, 1993. Storm Drainage Report. City of Renton. December 1993. Environmental Assessment. USDA Soil Conservation Service. In progress. Sediment Quality Testing. Herrera Environmental Consultants. In progress. SW 16th Street Pedestrian Trail Crossing Alternatives Study. City Transportation Division. Planned. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None known. 10. List any governmental approvals or permits that will be needed for your proposal, if known. Shoreline Substantial Development Permit Conditional Use Permit Fill and Grade Permit Fill and Grade License/Construction Permit Land Clearing and Tree Cutting Permit Variance Site Plan Approval (PedestrianTrail Only) Short Term Water Quality Modification Permit Hydraulic Project Approval Permit WSDOT Right-of-Way Construction Permit Section 404 Nationwide 14 Permit Section 404 Individual Permit Section 401 Water Quality Certification Coastal Zone Management Consistency Determination NEPA Environmental Assessment 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way, the SW Grady Way and 1-405 box culverts, the P-1 Channel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of this proposed project is to complete the construction of P- 1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent -3- to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P-1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide. The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the I- 405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Fill blocking the SW Grady Way box culvert would also be removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-I/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for -4- the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicle use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80 feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation ' Division in a planned study of the crossing alternatives. A glossary of terms is included as Exhibit E. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Exhibit C. B. ENVIRONMENTAL ELEMENTS 1. EARTH a. General description of the site (circle one) flat, rolling, hilly, steep slopes, mountainous, other The project area is generally flat, except for varied slopes of the Springbrook Creek channel, Oakesdale Avenue SW underpass, and 1-405 freeway. b. What is the steepest slope on the site (approximate percent slope?) Some portions of the stream bank slope which is eroding is at 100%, with a short, nearly vertical segment on the left bank (looking downstream) just to the north of 1-405. 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. The U.S.D.A. Soil Conservation Service Soil Survey for the King County Area, Washington, designates the soil in project area as urban land (Ur). The natural -5- soil layers of Urban land soils are defined as having been disturbed and/or covered with fill material. Several geotechnical studies have been performed in the project area for the purpose of determining the construction requirements of the adjacent roadways and their related structures. In these studies, the soil profile was examined using drilled borings and test pits of varying depths (to as much as 80 feet). The findings of the studies were similar and indicative of the area's history as a floodplain for the Green, White, Black, and Cedar Rivers. The soil profile reflected a layering of material likely due to stream bedload, floodplain, and alluvial deposition. Below the surface, several feet of sandy silt and silty sand were encountered in the borings with apparent lenses of clay, gravel, silt, and peat. The soil profile grades downward to more coarse and dense sand with increasing gravel proportions, but also with lenses of finer materials and debris. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. The City of Renton has mapped the Green River Valley area as a seismic hazard, due to the liquefaction potential of the unconsolidated sands present in the Valley soil profile. Even without the proposed project having been constructed, the adjacent structures are subject to liquefaction induced settlement. However, these structures were designed to accommodate the proposed channel improvement. The construction of the project is therefore not anticipated to impose unanticipated risks to structures in the project area due to seismic ground movement and acceleration. The 1-405 bridges in the vicinity are constructed on piling and other structures are founded on broad footings to reduce the risk of settlement due to liquefaction. A portion of the west bank of the existing channel north of 1-405 has been eroded to a near vertical slope and is therefore unstable. This area will be graded to a more stable 2 horizontal to 1 vertical slope and protected with rip rap and vegetation. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. A low flow channel will be constructed in the main channel, connecting with the low flow cells of the 1-405 and SW Grady Way box culverts. The low flow channel will have a 12-foot bottom width and 3 horizontal to 1 vertical side slopes. The overall top width of the low flow channel will be 27-feet. The main channel, including the low flow channel, averages 65-feet in width. To construct the proposed channel, the existing material necessary to achieve the proposed channel section subgrade will be removed. Subgrade is generally 1.5-feet below the proposed finish grade, with a portion of the proposed channel directly adjacent to the Oakesdale Avenue SW underpass and underdrain system overexcavated to 5-feet below the proposed finish grade to allow placement of a watertight PVC membrane. The underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, must be protected from the shortcircuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. To prevent this piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the membrane will be -6- connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. The use of sheet piling driven into the channel bottom to lengthen the flow path was also considered, but was not selected because the piling may reach refusal too soon to provide effective protection. The total amount of excavation is estimated to be 15,700 CY. A total of 3 1/2- feet of fill material will be placed on the membrane to achieve subgrade. To reach finish grade on a portion of the channel, including the low flow channel, a total of 1/2-foot of sandy filter material and 1-foot of clean., loose rip rap will be placed on the subgrade. Other areas of the channel not receiving rip rap that are subject to potential erosive flows will be brought to finish grade with fill material and overlain with an excelsior blanket. This will protect the exposed soil and allow vegetation to become established to further protect against erosion. Excavation is also proposed to allow for placement of concrete wing walls on the west side of the 1-405 and SW Grady Way box culverts and a gabion wall north of the SW 16th Street bridge. The west side of the proposed and existing channel between SW Grady Way, and 1-405 will be graded to a stable 2 horizontal to 1 vertical slope and a 1-foot depth of rip rap on 1/2-foot depth of filter material will be placed to protect against future erosive flows. The total estimated quantity of fill for the channel work is 8100 CY, including filter material and rip rap. Construction of the pedestrian trail shown in the plans will require an estimated 500 CY of fill to achieve subgrade. Fill material will be well graded sand to silty sand. The material will be from an approved gravel mining site and will arrive to the site via 1-405, SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. The specific source of the fill material and haul route is unknown at this time, but will be provided as a part of the final construction management plan, and will be submitted for approval to the City Development Services Division. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. Yes, soil erosion could occur in connection with the proposed project, since the entire area of channel and pedestrian trail construction will be cleared of existing vegetation. Erosion could occur during rain and/or wind storms that occur during the construction phase of the project. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. The project design includes a combination of plantings, rip rap, and erosion control blankets to minimize the erosion potential after construction. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Approximately 7000 SF of asphalt paving is proposed for the pedestrian trail construction (5% of the project area). 7 t h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any. • The contractor selected for the work will be required to submit a source and haul route plan for review of the City and SCS. • The contractor selected for the work will be required to submit disposal site and haul route plan for review of the City and SCS. • Any disturbed areas will be stabilized and restored to existing condition or better. • The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and washpads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. • The contractor will be required to submit shoring calculations for review by SCS and the City. The contractor shall coordinate with METRO and WSDOT as applicable. Shoring measures will be implemented as needed for excavation work near existing structures and the METRO interceptor pipeline which are to be undisturbed. • Incorporate the rip rap, planting, structural wall, and erosion control blanket features recommended by SCS. • Install PVC cutoff membrane in accordance with the recommendations of the report by CH2M Hill. 2. AIR a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Construction of the proposed project would not result in any significant impacts to existing air quality. During construction only minimal dust and construction equipment exhaust emissions are expected and would only be a temporary nuisance in the general area. -8- b. Are there any off-site sources of emission or odor that may affect your proposal? If so, generally describe. No. C. Proposed measures to reduce or control emissions or other impacts to air, if any: The area of exposed soil will be kept to a minimum during construction. Dust control measures will be employed during construction and disturbed soils will be covered with a suitable ground cover or stabilized by hydroseeding to prevent wind erosion. Street cleaning will be performed as needed. 3. WATER a. Surface Water: 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. Yes. The project is adjacent to, and includes portions of, an existing reach of Springbrook Creek that flows north. Springbrook Creek joins the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. The existing Springbrook Creek channel, including the reach in the project area, has been extensively modified and disturbed by dredging and vegetation management activities performed by adjacent land owners and Drainage District No. 1. In a June 1, 1989 inventory by SCS, the existing channel was noted to have open water approximately 15 to 20 foot wide with 2 to 3 feet of woody and herbaceous vegetation on each side of the channel. The existing channel under 1-405, however, has been severely eroded by flood waters and disturbed by subsequent shoreline anchoring efforts. A wetland inventory of the proposed project area was conducted on March 1, 1993. Eight sites were sampled and described. Only the southern 1-405 roadside drainage ditch was identified as a wetland using the methods of the Corps of Engineer's 1987 Wetland Delineation Manual and the 1989 Federal Manual for Identifying and Delineating Jurisdictional Wetlands. Two delineation methods are required because Springbrook Creek through the project area is not only under local jurisdiction, as defined by the 1989 Manual, but is also subject to the juridication of the Federal Clean Water Act, Section 404, administered by the Corps, as defined by 1987 Manual. The wetland (Wetland A) is linear in shape and approximately 0.01 acre in size per 100 lineal feet of ditch. Because of its size, type, location adjacent to 1-405, and history of disturbance the wetland is given a low quality, Category 3 rating according to the City's Wetlands Management Ordinance. -9- 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 entire project is within 200 feet of Springbrook Creek. Springbrook Creek, through the project area, is designated a Shoreline of the State by the Department of Ecology, which determined that the mean annual flow of the creek in the area of the project was equal to or greater than 20 cfs. The scope of work for the proposed channel and pedestrian trail improvements are described in Sections A.11 and B.1.e. According to Sections 4-32-3.C.1 and 4-32-15.A.54 of the City's Wetlands Management Ordinance, Wetland A is not considered a regulated wetland subject to the provisions of the OrdinanceWetland A is not subject to because it is a drainage ditch constructed for the purpose of conveyance of runoff. 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. An estimated 2100 CY of material will be removed from within the area defined by the ordinary high water mark of the existing channel of Springbrook Creek to achieve subgrade elevations for the proposed channel. An estimated 1700 CY of select fill material will be subsequently placed in this same area to raise the elevations from subgrade to finish grade. The source of fill material is not known at this time and is to be contractor supplied from an approved site as noted in Section BA.e. and BA.h. The material dredged from the existing channel will be disposed off-site at a location to be contractor determined, subject to the review of the City and SCS. The amount of fill material to be placed in the 1-405 south roadside ditch wetland for the purpose of establishing the pedestrian trail culvert crossing is estimated to be 40 CY. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. Yes. Springbrook Creek will be routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. This is necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. -10- The sequence and timing of the any bypass is to be contractor determined, subject to the review of the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. It is anticipated that construction of the channel north and south of 1-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the weather conditions at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. The entire project area lies within the 100-year floodplain according to Federal Emergency Management Agency Flood Insurance Rate Map 530033CO453D dated September 29, 1989. The FEMA Flood Insurance Study September 29, 1989 regulatory base flood (100-year) water surface elevation in the reach is 16.4 feet NGVD 1929 at SW 16th Street. 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 Water: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. Yes, ground .water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. The geotechnical reports noted in Section A.8. describe ground water levels at relatively shallow depths. Because of potentially high ground water conditions the contractor for the proposed project will be required to determine if conditions at the time of construction are low enough to allow construction. If not, the contractor will be required to construct well points at strategic locations in the project area to draw down the water table sufficiently. Before any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. The amount of ground water to be withdrawn is a function of the soil conditions, water table elevation, required drawdown, and wellpoint location and depth. Therefore, the number of wellpoints and the amount of groundwater that will be withdrawn cannot be estimated at this time. 2) Describe waste material 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. -11- No waste material will be discharge into the ground as part of this proposal. C. Water Runoff(including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. The reach of Springbrook Creek within the project area is an open channel which drains approximately 22 square miles of pervious and impervious land area from Kent, Tukwila, King County, and Renton. Surface water runoff reaches Springbrook Creek from these areas by overland flow or from a system of culvert and open channel point discharges along its length. Water from Springbrook Creek eventually reaches Puget Sound as described in Section B.3.a.1. The project itself does not propose to increase the surface runoff significantly. The increase in runoff, due to paving of the proposed pedestrian trail, will be only 0.03 cfs for the 100-year, 24-hour design storm event. The pedestrian trail is therefore exempt from providing on- site detention. The amount of flood water storage volume will be increased as a result of the proposed channel excavation of material from within the FEMA floodplain by 4 acre-feet. The project will also increase the flood conveyance capacity of Springbrook Creek and reduce upstream flooding. 2) Could waste material enter ground or surface waters? If so, generally describe. ' Streams can serve as groundwater recharge sources or as groundwater sinks depending upon the underlying soil and the water levels in the stream and groundwater. Dewatering of the project area will be used to keep work areas dry. The groundwater may be rich in dissolved iron, which may be oxidized upon exposure to air and settle out of solution to produce a rust colored plume downstream of any groundwater discharge point. This will temporarily reduce the aesthetic value of the affected area which will return to original condition overtime. No new significant sources of waste from paved areas subject to vehicle traffic will be created. Motorized traffic is not permitted on the proposed pedestrian trail, except as needed for channel or trail maintenance. Because maintenance will be necessary infrequently, the waste material associated with vehicular use will not be significant. Although the project is within an area designated as having surficial aquifer susceptibility, it is not regulated by the City's aquifer protection ordinance. No significant increase in groundwater recharge is expected because the membrane proposed for installation next to SW Oakesdale Avenue is an effective barrier. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any.- Prior to any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. All ground water withdrawals are to be directed, if conditions permit, into the METRO sanitary sewer, temporary -12- settling pond, or other device to minimize the discharge of iron rich water into Springbrook Creek. • The contractor will be required to submit plans outlining the proposed sequence and timing of any surface water bypass for review by the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. The contractor shall provide a backup system for maintaining or supplementing the function of any water bypass should the primary diversion fail or function inadequately. The bypass must be capable of handing mainstream Springbrook Creek flows of a minimum of the 2-year recurrence interval or design storm, a flow of 455 cfs (R.W. Beck, 1991). The contractor is to submit an emergency monitoring and contingency plan for City and SCS review prior to construction within the channel. The plan will outline measures to implement for immediate stabilization of disturbed areas at risk to flow of water, should the bypass system 2-year design capacity be in danger of being exceeded. See Section B.1.h. for other measures. 4. PLANTS a. Check or circle types of vegetation found on the site: _X_ deciduous tree: alder, maple, aspen, other evergreen tree: fir, cedar, pine, other _X shrubs _X grass ' pasture crop or grain _X_ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other water plants: water lily, eel grass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered? The entire area of channel and pedestrian trail construction will be cleared of existing vegetation. C. List threatened or endangered species known to be on or near the site. None known. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: The proposed project contains both wildlife and fish habitat improvements. For fish habitat both banks of the open, low flow channel will be planted with Bankers dwarf willows on 2-foot centers. Two wildlife areas are also to be established. Three hundred shrubs will be planted. The shrub type will be Pacific Serviceberry, Tall Oregon Grape, Rodosier Dogwood, and Common Chokecherry. These two areas will have four rows parallel to the channel with groups of 3 to 5 plants of the same species staggered between the rows. The plants will be planted on 3-foot centers. -13- Following permanent seeding, a portion of the area outside of the low flow channel that was disturbed during construction will be covered by an excelsior blanket for erosion control and to create a moisture layer to aid in vegetative establishment. Permanent seeding consists of proportions of the following: ryegrass, white clover, creeping foxtail, fesque, and trefoil. The contractor will post a maintenance bond in accordance with City requirements as surety that any needed maintenance of installed improvements will be performed. 5. ANIMALS a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: Birdst)ja::w` eron eagle on birds- ther Mammals: deer, bear, elk, ve ther Fish: bass, almo trod herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. None known. C. Is the site part of a migration route? If so, explain. Yes. Salmonids have been recorded migrating upstream at the Black River Pump Station. The fish counter at the pump station had recorded the following numbers for several years for the period from September through January. 1983-1984: 155 1986-1987: 82 1989-1990: 77 1984-1985: 119 1987-1988: 166 1990-1991: 69 1985-1986: 47 1988-1989: 95 1991-1992: 107 The Department of Fisheries has indicated that Springbrook Creek does support runs of coho salmon and other anadromous fish including steelhead, cutthroat trout and dolly varden trout. METRO in a 1990 report stated that the suitability of Springbrook Creek for salmonid spawning is poor and the rearing habitat is degraded. Upper tributary streams, such as Garrison Creek, may provide spawning and rearing habitat and Springbrook Creek provides the needed migration route. The proposed project will help to enhance the rearing habitat quality of Springbrook Creek. The existing channel will also provide off-channel flood storage that could be used as a resting area during time of high flows. d. Proposed measures to preserve or enhance wildlife, if any: • Construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. • Fish habitat components are included in the project design and consist of placing groups of three 24-inch diameter boulders in the low flow channel to create resting areas for migrating fish. Resting areas will also be created by placing boulders and rock rip rap around the boulders and up one of the side slopes of the low flow channel. A section of tree trunk with the root wad -14- exposed will be located in the channel bottom at a 30-degree angle to the cross section of the channel to provide additional resting and hiding area. There will be approximately eight of these in-stream habitat structures. • Plantings along the low flow channel as described in Section B.4.d. will provide shading for migrating fish in the low flow channel. 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. Electricity is anticipated for a pedestrian crossing traffic signal at SW 16th Street. The need for a signal (which would be coordinated with the pedestrian trail) and its preferred location will be determined by the City Transportation Division as noted in Section A.11 as part of Transportation's planned study of the crossing alternatives. 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: Use of high efficiency traffic control luminaries will help keep signal operation energy needs and costs to a minimum. 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. Because the reach of Springbrook Creek within the project area is downstream of potential point and non-point pollution sources, the sediments in the stream bed may contain contaminants. Contaminants are known to be present in the Springbrook Creek system and have been monitored at several locations. One of the monitoring stations for the City's Black River Water Quality Management Plan (BRWQMP) was at SW 16th Street. Contaminant levels in sediments sampled at this station in 1992 were determined to be below Model Toxics Control Act Cleanup Regulation (MTCA) cleanup levels. These levels apply to sediments disposed of on land other than in a permitted landfill. Dredging or other construction disturbance as part of this project could cause contaminated sediments that may be in the project reach to be suspended and carried downstream. Contaminants that may be in the dredge spoils could also be a potential health risk if not disposed of properly. Although sampling at SW 16th Street indicated that special disposal of the sediments would not be required, SCS has contracted with Herrera Consultants to test a surface sample and a sample at one foot depth at a total of four locations within the project area. The field work was complete at the end of September and a report of the results is expected by the end of the year. 1) Describe special emergency services that might be required. -i s- No special emergency services would be required. 2) Proposed measures to reduce or control environmental health hazards, if any: • Assess the Herrera sediment monitoring report once completed to determine if the pollutants are below levels requiring special disposal and/or if additional sediment testing is required. Additional testing may be necessary depending upon the requirements for use of the disposal site agreed upon by the site's owner. • If sediment monitoring results are found to exceed MTCA levels, obtain a permit from King County for disposal of the contaminated sediments at the Cedar Hills landfill permitted by King County. b. Noise 1) What types of noise exist in the area which may affect your project (for example:traffic, equipment, operation, other)? Traffic from 1-405 as well as surrounding arterial streets may be heard from the project site, but will not affect the project. Work will be conducted during the hours of peak noise generation from 1-405 and the surrounding arterial streets, and will not have a significant impact on the primarily commercial land use in the area. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Noise due to construction is expected for approximately four months from 7:00 am to 6:00 pm, five working days per week. If the contractor desires to work holidays, weekends, or other hours, permission shall be requested in writing subject to noise control conditions and requirements. 3) Proposed measures to reduce or control noise impacts, if any: Normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. 8. LAND AND SHORELINE USE a. What is the current use of the site and adjacent properties? The site is currently used as a stream corridor for conveying surface water runoff. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack site now being developed as the Boeing CSTC facilities, and slightly southeast of the METRO Wastewater Treatment Plant. The property to the north of 1-405 and west of the project channel is vacant land. -16- A single family dwelling with horse pasture is to the west of the channel, south of 1-405, and north of SW 16th Street. b. Has the site been used for agriculture? If so, describe. The Renton Green River Valley was historically used for agriculture and the project site and adjacent areas may have be used for such purposes, but not at the present time. C. Describe any structures on the site. Several concrete structures cross and border the project site. These include the 1-405 bridge and box culvert, the SW Grady Way box culvert, the SW 16th Street bridge, and the P-1 retaining walls. d. Will any structures be demolished? If so, what? No. e. What is the current zoning classification of the site? Portions of the site are zoned Medium Industrial (IM) and Commercial Office (CO). f. What is the current comprehensive plan designation of the site? Most of the site is designated Employment Area - Office, with the balance classified as Employment Area - Industrial. g. If applicable, what is the current shoreline master program designation of the site? The current designation of the project site is urban, pursuant to the Shorelines Master Program of the City of Renton (1990 - SMP 5.04.03). h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. The site or portions of the site have been classified as within or containing the following environmentally sensitive areas: 100-year floodplain, wetlands and streams, surficial aquifer susceptibility, and seismic hazards. See Sections 6.1 and B.3 for how the project will impact these areas. 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.- Not applicable. -1 7- I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project utilizes land area, which by its location and zoning designation, is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities consistent with the Shoreline Master Program goals and policies. The project increases the public accessibility to the shoreline, but preserves and improves the existing amenities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. 9. HOUSING a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. None. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. None. C. Proposed measures to reduce or control housing impacts, if any: Not applicable. 10. AESTHETICS a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s)proposed. Proposed concrete and rock gabion wing walls at the tallest height are approximately 10 feet high. b. What views in the immediate vicinity would be altered or obstructed? None, as the structures are located within the channel area below the adjacent surface grades. C. Proposed measures to reduce or control aesthetic impacts, if any: A habitat enhancement and planting plan will be implemented as part of the project to improve the aesthetics of this section of Springbrook Creek. -18- 11. LIGHT AND GLARE a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Not applicable. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not applicable. 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: Not applicable. 12. RECREATION a. What designated and informal recreational opportunities are in the immediate vicinity? Public trails along Springbrook Creek extend north and south of the project. Fort Dent Park, the Green River, and the Interurban trail are to the west and northwest. The Black River Riparian Forest lies to the north. 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. The project provides for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities of the Springbrook Creek shoreline area. 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. The 1979 SCS FEIS indicates the National Register of Historic Places stated there were no archaeological, historical, or unique properties of national significance within the project area. The Washington State Historic Preservation officer indicated four properties of historic significance are in the Green River valley, but not in the vicinity of the proposed project. To satisfy the requirements of Section 106 of the National Historic Preservation Act of 1966 and SCS regulations published in 7 CFR 656 on June 7, 1976, an archaeological reconnaissance of the ESGRW area was contracted in coordination with the National Parks Service with Grays Harbor College archaeologist, Lionel A. Brown. The investigation found that the potential is high -19- for the discovery of archaeological sites within the Green River area, but no previously unknown sites were found during the course of the survey. The report also determined that the ESGRWP project will have no adverse impacts upon the cultural resources within the watershed. This included the reach of the proposed project. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. Not applicable. C. Proposed measures to reduce or control impacts, if any: The contractor will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City of Renton, and the Washington State Historic Preservation Officer to determine the course of action. 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 project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street.. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Because of its limited access requirements and elevated grade access from 1-405 is not possible. SW Oakesdale Avenue drops below surrounding grade as it passes under 1-405 so access from this street is also not possible. The 1-405 interchange is west of the project area at West Valley Highway in the City of Tukwila. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? A public transit stop is located at the SW Oakesdale Avenue intersection with SW Grady Way within the project area. C. How many parking spaces would the completed project have? How many would the project eliminate? Not applicable. 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? Widening of the existing sidewalk and new sidewalk improvements are proposed at the southwest corner of the SW Grady Way and SW Oakesdale Avenue intersection to connect with the proposed pedestrian trail and to provide sufficient waiting area at the existing intersection crosswalk. A marked crosswalk and pedestrian crossing traffic control signal will be constructed at SW 16th Street to connect with the sidewalk and shoreline trail under construction as part of the Boeing CSTC project. These improvement are -20- proposed with either of the two options within the corridor (see Section A.11) under consideration. The pedestrian trail will extend north from the crosswalk location over to the existing channel to continue north following along its west bank. New sidewalk at SW 16th Street will be constructed at the north crossing waiting area only. No additional new sidewalk is proposed on the north side of SW 16th Street to discourage pedestrian use of the north side where there are no existing sidewalks or other marked crossings to travel to in the immediate vicinity. In accordance with the procedure described in Exhibit D, acquisition of a 15-foot permanent easement for the trail link is proposed to secure the necessary rights to allow public use. in accordance with the attachedThe easement will primarily follow the existing channel and minimize the area impact on the adjacent properties. Only the 80 foot segment directly north of SW 16th Street may have a greater land area impact if the crossing will be constructed at the Boeing CSTC driveway. This is because of its increased distance from the channel compared to the option of crossing opposite the shoreline trail south of SW 16th Street. e. Will the project use (or occur in the immediate vicinity oi) 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. Not applicable. g. Proposed measures to reduce or control transportation impacts, if any: The final crossing alternative and mitigation measures to be constructed will be determined by the City Transportation Division in a planned study of the crossing alternatives. For the options considered in this application the following measures are anticipated: • Provide a pedestrian traffic signal and marked crosswalk of SW 16th Street. • Construct signage in advance of the crossing to warn motorists of its location. • Modify the SW 16th Street and SW Oakesdale Avenue intersection to a three way stop to eliminate the free southbound right turn from SW Oakesdale Avenue onto SW 16th Street. 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. Yes. Limited maintenance (litter collection, sweeping) of the pedestrian trail will be required and is anticipated to be infrequent. This does not provide a significant increase in the scope of service already provided by the City Parks and Recreation Division. The maintenance could be performed by a volunteer task force. -21- Llmitied maintenance of the existing and proposed channel will be required and is also anticipated to be infrequent. Maintenance may include debris removal and vegetation management as necessary to ensure the safety of the public. This does not provide a significant increase in the scope of service already provided by the City Maintenance Division. b. Proposed measures to reduce or control direct impacts on public services, if any. None proposed. 16. UTILITIES a. Circle utilities currently available at the sit electricity natural gas water, efuse sese v elephon sanitary sewer'septic syste other Storm drainage. 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. The channel portion of the project is a storm drainage utility project designed to provide improved storm drainage service to the Springbrook Creek system and is described throughout this application. Storm drainage utilities are managed by local, state, and federal agencies. Electricity will be needed for temporary groundwater dewatering and may be needed for stream bypass construction activities. Puget Sound Power & Light provides electric service to the project area. C. SIGNATURE I, the undersigned, state that to the best of my knowledge the above information is true and complete. It is understood that the lead agency may withdraw any declaration of non- significance that it might issue in reliance upon this checklist should there be any willful misrepresentation,or willful lack of full disclosure on my part. Proponent: G=��/i , x, ,� ; ��P~ C .:• c� �'��i�c N ��.i'r-r,a cr. 1t� &TE-ky Uh 1 th Name Printed: c.v/?Li7 'T -,2-1AKA- T -,4c7,Ivi_1.� Z— Date: /2--j Z Z-f -22- Exhibit A PROJECT RELATIONSHIP WITH THE EAST SIDE GREEN RIVER WATERSHED PLAN The East Side Green River Watershed Plan (ESGRWP), also known as the Valley Drainage Study, has a long history dating back to the early 1960's when the local governments of Auburn, Kent, Tukwila, Renton, King County Conservation District, and King County requested federal flood assistance from the Soil Conservation Service (SCS) under the Watershed Protection and Flood Protection Act (Public Law 566). The SCS developed a work plan in 1965 which was approved by the United States Congress. This led to the construction of the Black River Pump Station (BRPS) in 1972. In 1972 the National Environmental Policy Act (NEPA) was enacted and it was determined that an Environmental Impact Statement (EIS) would be required prior to any future project improvements. A draft EIS issued in 1973 raised concerns regarding the environmental impacts posed by the plan. It was not until 1978 that a revised watershed plan was completed which provided for a reduced scope of work to more accurately reflect development trends and to address environmental concerns. A NEPA EIS was then prepared by SCS and approved at the federal level in 1979. Subsequent modifications to the 1978 revised watershed plan were finalized and approved by the local governmental sponsors along with an Environmental Mitigation Program in 1980. A 1981 amplification to the 1979 EIS was then prepared by the SCS to reflect the changes to the 1978 watershed plan. The plan consisted of constructing the P-1 Channel/P-9 Channel in the City of Renton and a series of channels in the City of Kent. The total plan consisted of approximately 11.1 miles of new channels with the P-1 Channel being the main channel with an average top width of 210 feet. In 1982 the local sponsors withdrew from the plan as a result of a disagreement over the equitable cost sharing for the local share of the plan construction cost. Following 1982, the City of Renton assumed lead agency responsibility from King County. With assistance from SCS the City of Renton constructed the BRPS forebay, the P-1 Channel from the forebay to SW Grady Way, and the SW Grady Way box culvert. Efforts to continue construction of the channel improvements identified in the watershed plan from SW Grady Way to SW 43rd Street were halted when City review of the NEPA EIS determined that the document did not adequately evaluate the environmental impacts of the overall plan. However given that SCS support would be withdrawn if the City did not rely on the existing environmental documents, it was agreed, with Ecology approval, that the City proceed to adopt the NEPA EIS as a local SEPA document. The process to formally adopt the NEPA EIS as a local SEPA document began in 1988. The adoption process generated serious concerns and comments from various regulatory agencies, environmental groups, and citizens who questioned the adequacy of the original NEPA EIS. The City then suspended the adoption process and conducted an Adequacy Determination Study for the NEPA EIS. This study identified deficiencies in the NEPA EIS with respect to wetland impacts, impacts to streams, wildlife and fish habitat, and water quality. In addition, the existing hydrologic and hydraulic models were considered out of date due to changes in the drainage system and advances in modeling technology. EAST SIDE GREEN RIVER WATERSHED PLAN Concurrently with environmental review of the NEPA EIS, the 1-405 box culvert, the Oakesdale Avenue SW underpass, and the P-1 retaining wall projects were constructed in conjunction with the state's 1-405 HOV lane project. These projects were constructed without the corresponding channel improvement when concerns about the adequacy of the 1979 NEPA EIS halted efforts to continue construction of the channel improvements identified in the modified 1978 ESGRWP. The City elected to move forward with the construction of the 1-405 culvert and P-1 retaining walls because these structural improvements would have been much more expensive if not done in conjunction with the HOV project. Until the 1979 NEPA EIS was determined to be inadequate, the SW Grady Way to SW 16th Street channel project was considered an integral segment of the system of improvements identified in the modified 1978 ESGRWP. However, the SW Grady Way to SW 16th Street improvement is now proposed to be implemented separately, but concurrently, with the effort to identify and evaluate future flood control alternative projects south of SW 16th Street in an updated ESGRWP and EIS. The proposed channel project is then the final segment of channel improvements located north of SW 16th Street to be constructed in accordance with the modified 1978 ESGRWP and 1979 SCS NEPA EIS, as supplemented through the City SEPA process. Because the project and updated ESGRWP are independent and separate, approval of this project would not imply approval of any element of the updated ESGRWP effort. The proposed project impact evaluation and mitigation is considered independent from the updated ESGRWP because the project would not predetermine or depend on future improvements identified in the updated plan. The existing 1-405, SW Grady Way, SW 16th Street, and Oakesdale Avenue SW streets confine this project's segment of Springbrook creek to a narrow, defined corridor. Also, all downstream improvements and major structures necessary for the proposed project have already been permitted and constructed. The impact evaluation and mitigation for the proposed project are identified in the SEPA checklist. For the updated ESGRWP there are several options for the location of future improvements south of SW 16th Street, as the location for these improvements is not so limited by existing streets and other existing development. Any future proposed alignment must be evaluated for impacts and compared with other alternative alignments through the updated ESGRWP for their effect on environmental resources. The proposed project, however, does not predetermine, depend upon, or foreclose opportunities for a future connection between this project segment and any future ESGRWP improvement, that potential connection being clearly defined by the existing channel location as it passes under the SW 16th Street bridge. The City has made significant progress toward an updated ESGRWP, and is committed to completion of the plan effort. A portion of the work was to be completed though the Black River Water Quality Management Plan (BRWQMP) funded in part by a Centennial Clean Water Fund grant from Ecology. Ecology approval of the final BRWQMP plan has been received. Page 2 EAST SIDE GREEN RIVER WATERSHED PLAN Updated hydrologic and hydraulic models and summary reports, including a preliminary alternatives analysis have been sent to SCS for review. Work is in progress to address SCS comments on the models and to extend the period of simulation to include water years 1989-91, as well as the most recent information on regional storm water detention facilities, which were not included in the recent modeling work. Because of the major storm events in 1990-91, the flow predicted by the recent modeling work could increase up to 20%. The preliminary alternatives analysis will be reevaluated using the increased flows and the reports updated. The flood control alternatives will be finalized and integrated into an updated ESGRWP with other related information for SEPA review. Following environmental review final design can be completed. The first phase of construction of the improvements to be identified in the updated ESGRWP is expected to start in 1996. H:DOCS:94-002:SSW:ps Page 3 RAD01007 ^ f—Watershed Black River King County Boundary Water ouality , Management Plan ..� ••' Study Area , . ��•' Panther Lake 05 King Count Garrison ,•.•'•' (" Renton Creek Renton • ORBS-+ -._. (' • •1 e Panther Creek `"� t1.pp� •1 King County r ,�•j"' J Valley rea N 167 Kent ' n b k S ri brook reek East Valley Road i 3 Springbrook Creek : e to N111 167 ! �_ _ 7u W I a creek r•�� Block River ` •ee ,`P Kent N f 81 181 ... Pump Station rukwilo " Kent N , Tukwila �\ V) / Kent -•-•� '��" / Lagoons - r—'L.� c !f RoposED ' / R der \ I-5 \�\ EAST SIDE GREEN RIVER WATERSHED NrS SOURcE: RW BECK MO ASSOCIAM x Cr x i) Exhibit C N PUMP SrATl0Al RE TON FORE BAY G pP South Renton Subbasin r— Pumping OA,-ESD/-\L6: �- Station -' rm t r R o) GR Any �..A E Basin ' Boundary Rolling \'\� SW 161h St. Hills Drain m l m l a Rolling Hills Subbasin z: �l P-9 Channel ,m .m 'g 181 > Panther Creek Wetland Valley Subbasin i sw am si �I sw 43ro sc •� Panther Creek Subbasin m� 167 ,F S.isznas<. ' LEGEND ---- Stream/Drainage Channel N-� Springbrook Springs b ` -- Storm Drain Pipe ¢ ' i --------- Subbasin � t F Subbasin Boundary F 0 1000 2000 3000 SCALE IN FEET 5'0uP E -H£/Z,QL_AA [-n�Vl/Lon/rr�f,ira� Black River Basin Water Quality Management Plan • Exhibit D SW GRADY WAY TO SW 16TH STREET PEDESTRIAN TRAIL PROPERTY RIGHTS ACQUISITION PLAN The City of Renton is proposing to acquire a minimum 15-foot wide permanent easement along the west bank of Springbrook Creek between SW Grady Way and SW 16th Street. The purpose of the easement is to allow construction of a 12-foot wide asphalt trail for public use across the 1-405 corridor to connect with the public trails to the north of SW Grady Way and to the south of SW 16th Street. The plan for acquiring the needed property rights for the pedestrian trail is shown below. TASK DESCRIPTION ESTIMATED NO. COMPLETION DATE 1 Surveyor Services Contract. The City will execute a contract 1/94 with a surveyor from the City's approved annual consultants contract list. The surveyor will be responsible for preparing the legal descriptions and drawings needed for the property rights conveyance documents. 2 Research and Assessment. Preparation and review of 2/94 appraisal, title report, and hazardous assessment documents will be coordinated by the City Attorney, if required. 3 Conveyance Documents. Concurrently with Task 2 the City 3/94 Attorney will prepare the necessary legal documents for the property rights transfer. 4 Negotiations. The City Attorney will coordinate negotiations 5/94 with the grantors. If, in a reasonable amount of time, agreement cannot be reached upon a reasonable settlement, then negotiations will be halted and condemnation proceedings initiated. 5 Condemnation. The City Attorney will prepare the necessary 10/94 documents, obtain Council approval by ordinance of the condemnation, and carry out condemnation proceedings, if required. H:DOCS:93-1093:SSW:ps Exhibit E GLOSSARY OF TERMS Acre-foot - The volume of water, 43,560 cubic feet, that will cover an area of one acre to a depth of one foot Aquifer - A geological unit of porous and permeable rock or soil capable of. yielding usable amounts of water Base flood - The 100-year flood, or that flood having a one percent chance of being equaled or exceeded in any given year Base flow - The water that flows in a stream in the absence of rainfall-supplied runoff water (the source of base flow may be lakes, snowmelt, or discharge of ground water into the stream) Best management practices (BMPs) - Structural or nonstructural controls used to treat urban stormwater runoff Contaminant - Any hazardous substance that does not occur naturally or is found at concentrations greater than natural background levels Design storm - A rainfall event of specified size and frequency (for example, a storm that occurs only once every 10 years) that is used to calculate runoff volume and peak discharge rate Flood, base - The 100-year flood, or that flood having a one percent chance of being equaled or exceeded in any given year Flood fringe - That portion of the floodplain not including the floodway that is generally associated with slow-moving or standing water Floodplain - The total area of the floodway plus the flood fringe subject to inundation by the base flood Floodway - The channel of a stream and any adjacent floodplain areas that, according to the applicable flood hazard regulation, are reasonably required to convey the base flood flow and must be kept free of encroachment so that the base flood can be carried without substantial increase in flood height Gabion - A wire basket or cage filled with rock used as a protective facing layer or structure to prevent soil erosion or embankment sloughing Ground water - Water stored beneath the surface of the earth, filling pores in soil, sand, or gravel; ground water is supplied by the seepage of rainwater, snowmelt, and other surface water into the soil (ground water discharges into lowland streams to maintain their base flow) r Habitat - The physical and chemical environment that provides all of the basic requirements for life and enables an organism to successfully complete its life cycle (the habitat includes food, shelter, and other elements such as oxygen and temperature) Headwater stream - A stream forming the source of another larger stream Hydrology - The science dealing with the properties, movement, and effects of water on the earth's surface, in the soil and rocks below, and in the atmosphere Impervious area - Impermeable surfaces, such as pavement or rooftops, that prevent the infiltration of water into the soil Nonpoint Source Pollution - Pollution that enters a water body from diffuse origins on the watershed Point Source Pollution - Pollution that enters a water body from pipe or channel conveyance Refusal - The point in the driving of a piling at which the effort needed to drive the piling deeper becomes prohibitive Rip Rap - A facing layer or protective mound of rock placed to prevent erosion or sloughing of a soil due to the flow of surface and stormwater runoff Riparian zone - A relatively narrow strip of land that borders a stream or river Salmonids - Salmon and trout species of fish Sediment - Minerals and organic material suspended in or settling to the bottom of surface water bodies (certain contaminants tend to collect on and adhere to sediment particles) Sheet flow - Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel Storm flow - The portion of flow that reaches the stream shortly after a storm event Surface water - Lakes, rivers, ponds, streams, inland waters, saltwaters, and all other watercourses Surficial Aquifer Susceptability - A index used to rank the potential for contaminants to infiltrate through the soil into an aquifer near the ground surface Suspended solids - Particles, both mineral (clay and sand) and organic (algae and small pieces of decomposed plant and animal matter) that are suspended in water and transported in stream flow Tightlining - The piping of urban runoff to protect easily eroded stream channels from the effects of high flow peaks Turbidity - A measure of water clarity based on cloudiness caused by the suspension of minute particles, usually algae, silt, or clay Water quality criteria - Specific levels of water quality that are expected to render a body of water suitable for its designated use; the criteria are based on specific pollutant properties and levels that would make the water harmful if used for drinking, swimming, farming, fish production, or industrial processes Watershed - The land area, defined by topographic divides, that drains into a stream Wetland - A habitat where the influence of surface water or ground water has resulted in development of plant or animal communities adapted to aquatic or intermittently wet conditions; wetlands include tidal flats, shallow subtidal areas, swamps, marshes, wet meadows, bogs, and similar areas Wing Wall - A retaining wall adjoining and extending from a bridge abutment, box culvert exterior wall, or similar structure that is used to retain the soil embankment associated with that structure Source: Renton, City of. May 1993. Black River Water Quality Management Plan. Prepared by R. W. Beck & Associates and Herrera Environmental Consultants. Seattle, WA H:DOCS:94-003:SSW:ps STArg o f o � y m 0 1889� STATE OF WASHINGTON DEPARTMENT OF ECOLOGY P.O. Box 47600 • Olympia, Washington 98504-7600 • (206)407-6000 • TDD Only(Hearing Impaired)(206)407-6006 May 24, 1994 Mr. Ron Straka MAY 3 11994 Renton Surface Water Utility R sTQN 200 Mill Avenue S Renton, WA 98055 E,ngin� rlr�g uopt. Dear Mr. Straka: Re: City of Renton Permit #LUA-94-001. . . Renton Surface Water Utility - Applicant Shoreline Substantial Development Permit #1994-15577 The subject Shoreline Management Substantial Development permit has been filed with this office by the City of Renton on May 6, 1994. If this permit is not appealed to the Shorelines Hearings Board on or before June 6, 1994, authorized construction may begin. Other federal, state, and local laws regulating such construction shall be complied with. Unless an appeal is filed, this letter constitutes final notification of action on this permit. Sincerely, K-Y Su Permit Coordinator Shorelands and Coastal Zone Management Program KYS:pz RECSDP.WP cc: Laureen Nicolay, City of Renton SC-Tt 10,100a tow ,. CITY OF RENTON "LL ' Planning/Building/Public Works Department e Earl Clymer, Mayor May 5, 1994 MAY 5 1994 Shoreline Permit Coordinator CITY OF RENTON Shorelands & Coastal Zone Management Program Engineering Dept. Department of Ecology P. O. Box 47690 Olympia, WA 98504-8711 SUBJECT: Shoreline Management Substantial Development Permit 1-405 Box Culvert/P-1 Channel Improvement(Springbrook Creek) File No. LUA-94-001, SA, ECF, SP, V, SM, CU Dear Permit Coordinator: Enclosed is the Shoreline Substantial Development Permit for the above-referenced project. The permit was issued by the City of Renton on May 4, 1994. We are filing this action with the Department of Ecology and the Attorney General per WAC 173-14- 090. Please review this permit and attachments, and call me at (206) 277-6168 if you have any questions or need additional information. Sincerely, i' Lenora Blauman, f roject Manager Development Se ,Ices Division Enclosures: Attachment A: Copy of Original Application Attachment B: Affidavit of Public Notice/Publication Attachment C: Site Plans Attachment D: SEPA Compliance Attachment E: Copy of Final Order CC: D.O.E., NW District Office Attorney General's Office City of Renton, Development Services Division City of Renton,Transportation Systems City of Renton, Utility Systems Applicant SHLTR.DOC 200 Mill Avenue South - Renton, Washington 98055 THIS PAPER CONTAINS 5011.RECYCLED MATERIAL,10%POST CONSUMER CITY OF RENTON SHORELINE MANAGEMENT ACT OF 1971 PERMIT FOR SHORELINE MANAGEMENT SHORELINE SUBSTANTIAL DEVELOPMENT PERMIT APPLICATION NO.: LUA-94-001, SA, ECF, SP, V, SM, CU DATE RECEIVED: January 5, 1994 DATE OF PUBLICATION: January 7, 1994 and January 14, 1994 DATE APPROVED: May 4, 1994 DATE DENIED: N/A TYPE OF ACTION(S): [X] Substantial Development Permit [ ] Conditional Use Permit [ ] Variance Permit Pursuant to Chapter 90.58 RCW, the City of Renton has granted a permit: This action was taken on the following application: APPLICANT: City of Renton Surface Water Utility DEVELOPMENT DESCRIPTION: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. Native vegetative cover will be provided on the shoreline, adjacent to the culvert to support/enhance the native environment. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. LEGAL DESCRIPTION: The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. SEC-TWNP-R: Section 24, Township 23 North, Range 4 East WITHIN SHORELINES OF: Springbrook Creek SHSUBDEV.DOC City of Renton P/B/PW Department Shoreline Substantial Development Permit 1-405 BOX CULVER TIP-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page 2 of 2 SHORELINE OF STATEWIDE SIGNIFICANCE (YES/NO): No ENVIRONMENT DESIGNATION: Urban APPLICABLE MASTER PROGRAM: Renton's Shoreline Master Program The following section/page of the Master Program is applicable to the development: Section 3.01, 3.03 Page 13 Section 4.01.02.A.2 Page 14 Section 4.02.02.A, 4.02.02.0 Page 15 Section 7.16.03 Page 36 - 37 Section 7.18.01 Page 38 Section 7.18.03.D Page 39 Development of this project shall be undertaken pursuant to the following terms and conditions: The applicant shall comply with the conditions established by the City of Renton Environmental Review Committee in the Declaration of Non-Significance issued on February 2, 1994. The applicant shall comply with the conditions established by the City of Renton Hearing Examiner in the Report and Decision issued on April 19, 1994. This permit is granted pursuant to the Shoreline Management Action of 1971 and pursuant to the following: 1. The issuance of a license under the Shoreline Management Act of 1971 shall not release the applicant from compliance with federal, state, and other permit requirements. 2. This permit may be rescinded pursuant to Section 14(7) of the Shoreline Management Act of 1971 in the event the permittee fails to comply with any condition hereof. 3. A construction permit shall not be issued until thirty (30) days after approval by the City of Renton Development Services Division or until any review proceedings initiated within this thirty (30) day review period have been completed. �e 4 f 9y Planning t blic Works Administrator Date H:DOCS:94-441:SS W:ps CC: D.O.E., NW District Office Attorney General's Office City of Renton, Development Services Division City of Renton,Transportation Systems City of Renton, Utility Systems Applicant SHSUBDEV.DOC City of Renton P/B/PW Department Shoreline Substantial Development Permit 1-405 BOX CULVER TIP-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEKI LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page2 of 6 Attachment A: Copy of Original Application SHLTR.DOC CITY OF RENTON DEVELOPMENT SERVICES DIVISION MASTER APPLICATION i OWNER(S) PROJECT INFORMATION (cont) I Note It there rs more than one legal owner,please attach an EXISTING LAND USE(S): additions;notarized Master application for each owner. Most of the site is designated employment NAME area-office, with the balance classified CITY OF RENTON AND OTHERS. as employment area-industrial . Office-2.4 Property rights for the project acres; Industrial-0.4 acres between I-405 an ADDRESS will be obtained prior to construc io SW 16th St and within east 1/2 of the SE 1/4 SPP affidavit of ownership helow- and NE 1/4 of Sec 24, T23N,R4E. EXISTING ZONING CITY ZIP Portions of the project are zoned medium industrial (1M) and commercial office (CO) . 1M-1.2 acres between I-405 and SW 16th St. TELEPHONE NU:✓BER U�gIth of I-405 and so of SW 16ti St I CONTACT PERSON/APPLICANT N/A NAME Ron Straka I City of Renton PROPOSED ZONING Surface derUtility ADDRESS 200 Mill Avenue South N/A i i CITY ZIP SITE AREA($O. Fr OR ACREAGE) Renton, WA 98055 Project area is approximately 3 1/4 acres. TELEPHONE NUMBER: 206 277-5548 PROJECT VALUE i PROJECT INFORMATION Approximately $600,000 DROJECT OR DEVELOPMENT NAME. IS THE SITE LOCATED IN AN ENVIRONMENTALLY SENSITIVE AREA Springbrook Creek/P-1 Channel Improvement Yes. The site or portions of the site have, been classified as within or containing the e PROPERTY/PROJECT ACDRESS(S)/LOCATION: At\r )IPER PR �TIC� WWI Wetldo S, See legal description. ejtc_ No KING COUNTY ASSESSORS ACCOUNT NUMBER(S) 2423049004 2423049126 IS THE SITE LOCATED IN THE SEWER MORATORIUM AREA? I 12423049054 2423049022 i 3340406255 3340405300 No. i r LEGAL DESCRIPTION OF PROPERTY (Attach separate sheet if needed) j See attached. LEGAL DESCRIPTION OF PROPERTY The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the Metro Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. H:DOCS:93-1 109:SSW:ps CITY OF,RENTON DEVELOPMENT SERVICES:DIVISION FCERITIFICATION OFSURROUNDING .PROPERTYOWNERSHIP within 30o feet:of thesbbject site ***FOR OFFICIAL USE ONLY— PROJECT NAME: APPLICANT: APPLICATION NO(S): The following is a list of property owners within 300 feet of the subject site. The Development Services Division will notify these individuals of the proposed development. NAME ADDRESS ASSESSOR'S PARCEL NUMBER See attached. SW GRADY WAY TO SW 16TH STREET PEDESTRIAN TRAIL PROPERTY RIGHTS ACQUISITION PLAN The City of Renton is proposing to acquire a minimum 15-foot wide permanent easement along the west bank of Springbrook Creek between SW Grady Way and SW 16th Street. The purpose of the easement is to allow construction of a 12-foot wide asphalt trail for public use across the 1-405 corridor to connect with the public trails to the north of SW Grady Way and to the south of SW 16th Street. The plan for acquiring the needed property rights for the pedestrian trail is shown below. TASK DESCRIPTION ESTIMATED NO. COMPLETION DATE 1 Surveyor Services Contract. The City will execute a contract 1/94 with a surveyor from the City's approved annual consultants contract list. The surveyor will be responsible for preparing the legal descriptions and drawings needed -for the property rights conveyance documents. 2 Research and Assessment. Preparation and review of 2/94 appraisal, title report, and hazardous assessment documents will be coordinated by the City Attorney, if required. 3 Conveyance Documents. Concurrently with Task 2 the City 3/94 Attorney will prepare the necessary legal documents for the property rights transfer. 4 Negotiations. The City Attorney will coordinate negotiations 5/94 with the grantors. If, in a reasonable amount of time, agreement cannot be reached upon a reasonable settlement, then negotiations will be halted and condemnation proceedings initiated. 5 Condemnation. The City Attorney will prepare the necessary 10/94 documents, obtain Council approval by ordinance of the condemnation, and- carry out condemnation proceedings, if required. H:DOCS:93-1093:SS W:ps 2423049004 2423049022 2423049026 PUGET WESTERN INC BOEING COMPANY METRO ACCOUNTS PAYABLE !9515 NORTH CREEK PKWY #310 PO BOX 3707 M/S 1F-09 SORENTONPR-5432-50706-D50218 130THELL WA 98011 SEATTLE WA 98124 821 2ND AVE SEATTLE WA 98104 2423049048 2423049049 2423049050 BOEING COMPANY BOEING COMPANY BOEING COMPANY PO BOX 3707 M/S 1F-09 PO BOX 3707 M/S 1F-09 PO BOX 3707 M/S 1F-09 SEATTLE WA 98124 SEATTLE WA 98124 SEATTLE WA 98124 2423049053 2423049054 2423049056 METRO BROWN L M & MOODY D A LONGACRES JOINT VENTURE 821 SECOND AVE 13975 INTERURBAN AVE S 921 MIDDLE FORK RD EXCHANGE BUILDING SEATTLE WA 98168 ONALASKA WA 98570 SEATTLE WA 98104 2423049061 2423049066 2423049097 GUY CHARLES B CITY OF SEATTLE METRO 3101 SE 5TH 821 2ND AVE EXCHANGE BLDG SEATTLE/METRO RENTON WA 98055 SEATTLE WA 98104 821 2ND AVE SEATTLE WA 98104 2423049098 2423049104 2423049107 CITY OF RENTON PUGET SOUND POWER&LIGHT CO PUGET WESTERN INC 200 MILL AVE S PROPERTY TAX DEPT 19515 NORTH CREEK PRKWY STE RENTON WA 98055 PO BOX 90868 310 BELLEVUE WA 98009 BOTHELL WA 98011 2423049108 2423049110 2423049112 PUGET WESTERN INC PUGET SOUND POWER & LIGHT SEPANEN DAVID C+PATRICIA L 19515 NORTH CREEK PRKWY STE PROPERTY TAXES 16709 SE JONES RD 310 PO BOX 90868 RENTON WA 98058 BOTHELL WA 98011 BELLEVUE WA 98009 2423049124 2423049125 2423049126 MOEN RUTH A MUNICIPALITY OF METRO SEATT MUNICIPALITY OF METRO SEA 9709 3RD AVE N E 821 SECOND AVE M/S 94 821 SECOND AVE M/S 94 SEATTLE WA 98115 SEATTLE WA 98104 SEATTLE WA 98104 3340405300 3340406120 3340406125 GROUP HEALTH COOP/PUGET SND BITNEY DEAN CITY OF RENTON 521 WALL ST W+GROUWS,CHARLE CITY HALL SEATTLE WA 98121 108 FACTORY AVE N,STE 2 200 MILL AVE S RENTON WA 98055 RENTON WA 98055 3340406255 3340406261 3340406625 KING COUNTY MCLEOD SUSAN N CUMMINS NORTHWEST INC 500 KC ADMIN BLDG 41 SPINOSA 811 SW GRADY WAY SEATTLE WA 98104 LAKE OSWEGO OR 97035 RENTON WA 98057 3340407100 9188000125 9188000148 CASEY FAMILY PROGRAM PUGET SOUND POWER& LIGHT FIRST CITY WASHINGTON INC 2033 6TH AVE SUITE 1100 PROPERTY TAXES 700 5TH AVE STE 6000 SEATTLE WA 98121 PO BOX 90868 SEATTLE WA 98104 BELLEVUE WA 98009 ASSESSOR'S PARCEL NAME ADDRESS NUMBER Certification hereby certify that the above list(s) of adjacent property owners and t eir addresses were taken from the records of the King County Assessor as prescribed by �.• aES� '�. .�• s • %1 2d and sworn to before me, a •' Qiy Pub •` Sid for the State of Washington, rs�dirfl� ,v on the yyi mqaY oL�r :I f U r •ASHEN ••', Signed: *****For Office Use Only***'t**' CERTIFICATION FOR MAILING hereby certify that noticOof�'ih'e.pending aforerrienUoned project' was mailed on } = ` `to eati`�jisted adjaceni'property owner as prescribed by law. ATTEST: -Su,bscrib'ed and sworn to before me a Notaoublic,'iti a -for the State of Washington residing at " on the .. day of . .• .` :> is Sign ed '`h ,l CITY OF RENTON ENVIRONMENTAL CHECKLIST PURPOSE OF CHECKLIST: The State Environmental Policy Act (SEPA), Chapter 43.21C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An Environmental Impact Statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help the agency decide whether an EIS is required. INSTRUCTIONS FOR APPLICANTS: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or"does not apply". Complete answers to the questions now may avoid unnecessary delays later_ Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you ran. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. USE OF CHECKLIST FOR NONPROJECT PROPOSALS: Complete this checklist for nonproject proposals, even though questions may be answered "does not apply_" IN ADDITION, complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). For nonproject actions (actions involving decisions on policies, plans and programs), the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposal," "proposer," and "affected geographic area," respectively. A. BACKGROUND 1. Name of proposed project, if applicable: Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street 2. Name of applicant.- City of Renton Surface Water Utility 3. Address and phone number of applicant and contact person: Ronald J. Straka Staff Contact: City of Renton Surface Water Utility Scott Woodbury, Project Manager 200 Mill Avenue South City of Renton Surface Water Utility Renton, WA 98055 206-277-5547 4. Date checklist prepared., December 1993 5. Agency requesting checklist: City of Renton Planning/Building/Public Works Department 6. Proposed timing or schedule (including phasing, if applicable): Construction is proposed to occur in the summer of 1994. Any work within the channel of Springbrook Creek is proposed to be completed within the Washington State Department of Fisheries June 15-September 15 "fisheries window". 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? if yes, explain. No. This project is the final phase of a series of flood control improvements constructed north of SW 16th Street under the 1979 East Side Green River Watershed Plan Final Environmental Impact Statement and 1981 Amplification. An updated watershed plan and EIS are being prepared to define the scope and impact of future flood control improvements south of SW 16th Street. See Project Relationship with the Green River Watershed Plan (Exhibit A). 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Final Environmental Impact Statement. USDA Soil Conservation Service. June 1979. Amplification of Final Environmental Impact Statement. USDA Soil Conversation Service. February 1981_ Report of Geotechnical Investigation, Box Culvert, SW Grady Way. GeoEngineers, Inc. October 31, 1984. Geotechnical Engineering Evaluation for P-1 Channel - SR405 Box Culvert. Hong Consulting Engineers. July 17, 1986. Geotechnical Report, Oakesdale Avenue. CH2M Hill. September 1987. Report of Geotechnical Investigation, Proposed Box Culvert, SW 16th Street. GeoEngineers, Inc. May 25, 1988. Biological Assessment. USDA Soil Conservation Service. June 1, 1989. -2- East Side Green River Watershed Hydrologic Analysis. Northwest Hydraulic Consultants, Inc. December 1991. East Side Green River Watershed Plan Hydraulic Analysis Report. R.W. Beck and Associates. March 1992. City of Tukwila Nelson Place/McLeod/Boeing CSTC Storm Drainage Study Technical Report. HCW-L. December 29, 1992. Black River Water Quality Management Plan. R.W. Beck &Associates. May 1993. Wetlands Determination. USDA Soil Conservation Service. June 1, 1993, November 3, 1993, November 29, 1993. Storm Drainage Report. City of Renton. December 1993. Environmental Assessment. USDA Soil Conservation Service. In progress. Sediment Quality Testing. Herrera Environmental Consultants. In progress. SW 16th Street Pedestrian Trail Crossing Alternatives Study. City Transportation Division. Planned. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None known. 10. List any governmental approvals or permits that will be needed for your proposal, if known. Shoreline Substantial Development Permit Conditional Use Permit Fill and Grade Permit Fill and Grade License/Construction Permit Land Clearing and Tree Cutting Permit Variance Site Plan Approval (PedestrianTrail Only) Short Term Water Quality Modification Permit Hydraulic Project Approval Permit WSDOT Right-of-Way Construction Permit Section 404 Nationwide 14 Permit Section 404 Individual Permit Section 401 Water Quality Certification Coastal Zone Management Consistency Determination NEPA Environmental Assessment 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way, the SW Grady Way and 1-405 box culverts, the P-1 Chan nel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of this proposed project is to complete the construction of P- 1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent -3- to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P-1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide_ The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the I- 405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Fill blocking the SW Grady Way box culvert would also be removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for -4- the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicle use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80.feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation Division in a planned study of the crossing alternatives. A glossary of terms is included as Exhibit E. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Exhibit C. B. ENVIRONMENTAL ELEMENTS 1. EARTH a. General description of the site (circle one) flat, rolling, hilly, steep slopes, mountainous, other The project area is generally flat, except for varied slopes of the Springbrook Creek channel, Oakesdale Avenue SW underpass, and 1-405 freeway. b. What is the steepest slope on the site (approximate percent slope?) Some portions of the stream bank slope which is eroding is at 100%, with a short, nearly vertical segment on the left bank (looking downstream) just to the north of 1-405_ 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. The U.S.D.A. Soil Conservation Service Soil Survey for the King County Area, Washington, designates the soil in project area as urban land (Ur). The natural -5- soil layers of Urban land soils are defined as having been disturbed and/or covered with fill material. Several geotechnical studies have been performed in the project area for the purpose of determining the construction requirements of the adjacent roadways and their related structures. In these studies, the soil profile was examined using drilled borings and test pits of varying,depths (to as much as 80 feet). The findings of the studies were similar and indicative of the area's history as a floodplain for the Green, White, Black, and Cedar Rivers. The soil profile reflected a layering of material likely due to stream bedload, floodplain, and alluvial deposition. Below the surface, several feet of sandy silt and silty sand were encountered in the borings with apparent lenses of clay, gravel, silt, and peat. The soil profile grades downward to more coarse and dense sand with increasing gravel proportions, but also with lenses of finer materials and debris. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. The City of Renton has mapped the Green River Valley area as a seismic hazard, due to the liquefaction potential of the unconsolidated sands present in the Valley soil profile. Even without the proposed project having been constructed, the adjacent structures are subject to liquefaction induced settlement. However, these structures were designed to accommodate the proposed channel improvement. The construction of the project is therefore not anticipated to impose unanticipated risks to structures in the project area due to seismic ground movement and acceleration. The 1-405 bridges in the vicinity are constructed on piling and other structures are founded on broad footings to reduce the risk of settlement due to liquefaction. A portion of the west bank of the existing channel north of 1-405 has been eroded to a near vertical slope and is therefore unstable. This area will be graded to a more stable 2 horizontal to 1 vertical slope and protected with rip rap and vegetation. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. A low flow channel will be constructed in the main channel, connecting with the low flow cells of the 1-405 and SW Grady Way box culverts. The low flow channel will have a 12-foot bottom width and 3 horizontal to 1 vertical side slopes. The overall top width of the low flow channel will be 27-feet. The main channel, including the low flow channel, averages 65-feet in width. To construct the proposed channel, the existing material necessary to achieve the proposed channel section subgrade will be removed. Subgrade is generally 1.5-feet below the proposed finish grade, with a portion of the proposed channel directly adjacent to the Oakesdale Avenue SW underpass and underdrain . system overexcavated to 5-feet below the proposed finish grade to allow placement of a watertight PVC membrane. The underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, must be protected from the shortcircuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. To prevent this piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the membrane will be -6- connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. The use of sheet piling driven into the channel bottom to lengthen the flow path was also considered, but was not selected because the piling may reach refusal too soon to provide effective protection. The total amount of excavation is estimated to be 15,700 CY. A total of 3 1/2- feet of fill material will be placed on the membrane to achieve subgrade. To reach finish grade on a portion of the channel, including the low flow channel, a total of 1/2-foot of sandy filter material and 1-foot of clean., loose rip rap will be placed on the subgrade. Other areas of the channel not receiving rip rap that are subject to potential erosive flows will be brought to finish grade with fill material and overlain with an excelsior blanket. This will protect the exposed soil and allow vegetation to become established to further protect against erosion. Excavation is also proposed to allow for placement of concrete wing walls on the west side of the 1-405 and SW Grady Way box culverts and a gabion wall north of the SW 16th Street bridge. The west side of the proposed and existing channel between SW Grady Way and 1-405 will be graded to a stable 2 horizontal to 1 vertical slope and a 1-foot depth of rip rap on 1/2-foot depth of filter material will be placed to protect against future erosive flows. The total estimated quantity of fill for the channel work is 8100 CY, including filter material and rip rap. Construction of the pedestrian trail shown in the plans will require an estimated 500 CY of fill to achieve subgrade. Fill material will be well graded sand to silty sand. The material will be from an approved gravel mining site and will arrive to the site via 1-405, SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. The specific source of the fill material and haul route is unknown at this time, but will be provided as a part of the final construction management plan, and will be submitted for approval to the City Development Services Division. f. Could erosion occur as a result of clearing, construction, or use? if so, generally describe. Yes, soil erosion could occur in connection with the proposed project, since the entire area of channel and pedestrian trail construction will be cleared of existing vegetation. Erosion could occur during rain and/or wind storms that occur during the construction phase of the project. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. The project design includes a combination of plantings, rip rap, and erosion control blankets to minimize the erosion potential after construction. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Approximately 7000 SF of asphalt paving is proposed for the pedestrian trail construction (5% of the project area). h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any.- The contractor selected for the work will be required to submit a source and haul route plan for review of the City and SCS. • The contractor selected for the work will be required to submit disposal site and haul route plan for review of the City and SCS. Any disturbed areas will be stabilized and restored to existing condition or better. The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and washpads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. • The contractor will be required to submit shoring calculations for review by SCS and the City. The contractor shall coordinate with METRO and WSDOT as applicable. Shoring measures will be implemented as needed for excavation work near existing structures and the METRO interceptor pipeline which are to be undisturbed. • Incorporate the rip rap, planting, structural wall, and erosion control blanket features recommended by SCS. • Install PVC cutoff membrane in accordance with the recommendations of the report by CH21VI Hill. 2. AIR a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known_ Construction of the proposed project would not result in any significant impacts to existing air quality. During construction only minimal dust and construction equipment exhaust emissions are expected and would only be a temporary nuisance in the general area. -8- b. Are there any off-site sources of emission or odor that may affect your proposal? If so, generally describe. No. C. Proposed measures to reduce or control emissions or other impacts to air, if any: The area of exposed soil will be kept to a minimum during construction. Dust control measures will be employed during construction and disturbed soils will be covered with a suitable ground cover or stabilized by hydroseeding to prevent wind erosion. Street cleaning will be performed as needed. 3. WATER a. Surface Water: 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. Yes. The project is adjacent to, and includes portions of, an existing reach of Springbrook Creek that flows north. Springbrook Creek joins the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. The existing Springbrook Creek channel, including the reach in the project area, has been extensively modified and disturbed by dredging and vegetation management activities performed by adjacent land owners and Drainage District No. 1. In a June 1, 1989 inventory by SCS, the existing channel was noted to have open water approximately 15 to 20 foot wide with 2 to 3 feet of woody and herbaceous vegetation on each side of the channel. The existing channel under 1-405, however, has been severely eroded by flood waters and disturbed by subsequent shoreline anchoring efforts. A wetland inventory of the proposed project area was conducted on March 1, 1993. Eight sites were sampled and described. Only the southern 1-405 roadside drainage ditch was identified as a wetland using the methods of the Corps of Engineer's 1987 Wetland Delineation Manual and the 1989 Federal Manual for Identifying and Delineating Jurisdictional Wetlands. Two delineation methods are required because Springbrook Creek through the project area is not only under local jurisdiction, as defined by the 1989 Manual, but is also subject to the juddication of the Federal Clean Water Act, Section 404, administered by the Corps, as defined by 1987 Manual. The wetland (Wetland A) is linear in shape and approximately 0.01 acre in size per 100 lineal feet of ditch. Because of its size, type, location adjacent to 1-405, and history of disturbance the wetland is given a low quality, Category 3 rating according to the City's Wetlands Management Ordinance. -9- 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 entire project is within 200 feet of Springbrook Creek, Springbrook Creek, through the project area, is designated a Shoreline of the State by the Department of Ecology, which determined that the mean annual flow of the creek in the area of the project was equal to or greater than 20 cfs. The scope of work for the proposed channel and pedestrian trail improvements are described in Sections A.11 and B.1.e. According to Sections 4-32-3.C.1 and 4-32-15.A.54 of the City's Wetlands Management Ordinance, Wetland A is not considered a regulated wetland subject to the provisions of the OrdinanceWetland A is not subject to because it is a drainage ditch constructed for the purpose of conveyance of runoff. 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. An estimated 2100 CY of material will be removed from within the area defined by the ordinary high water mark of the existing channel of Springbrook Creek to achieve subgrade elevations for the proposed channel. An estimated 1700 CY of select fill material will be subsequently placed in this same area to raise the elevations from subgrade to finish grade. The source of fill material is not known at this time and is to be contractor supplied from an approved site as noted in Section BA.e. and 13.1.11. The material dredged from the existing channel will be disposed off-site at a location to be contractor determined, subject to the review of the City and SCS. The amount of fill material to be placed in the 1-405 south roadside ditch wetland for the purpose of establishing the pedestrian trail culvert crossing is estimated to be 40 CY. 4) ill the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. Yes. Springbrook Creek will be routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. This is necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. The sequence and timing of the any bypass is to be contractor determined, subject to the review of the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. It is anticipated that construction of the channel north and south of 1-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the weather conditions at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. The entire project area lies within the 100-year floodplain according to Federal Emergency Management Agency Flood Insurance Rate Map 530033CO453D dated September 29, 1989. The FEMA Flood Insurance Study September 29, 1989 regulatory base flood (100-year) water surface elevation in the reach is 16.4 feet NGVD 1929 at SW 16th Street. 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 Water. 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. Yes, ground water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. The geotechnical reports noted in Section A.8. describe ground water levels at relatively shallow depths. Because of potentially high ground water conditions the contractor for the proposed project will be required to determine if conditions at the time of construction are low enough to allow construction. If not, the contractor will be required to construct well points at strategic locations in the project area to draw down the water table sufficiently. Before any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. The amount of ground water to be withdrawn is a function of the soil conditions, water table elevation, required drawdown, and wellpoint location and depth. Therefore, the number of wellpoints and the amount of groundwater that will be withdrawn cannot be estimated at this time. 2) Describe waste material 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. No waste material will be discharge into the ground as part of this proposal. C. Water Runoff(including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. The reach of Springbrook Creek within the project area is an open channel which drains approximately 22 square miles of pervious and impervious land area from Kent, Tukwila, King County, and Renton. Surface water runoff reaches Springbrook Creek from these areas by overland flow or from a system of culvert and open channel point discharges along its length. Water from Springbrook Creek eventually reaches Puget Sound as described in Section B.3.a.1. The project itself does not propose to increase the surface runoff significantly. The increase in runoff, due to paving of the proposed pedestrian trail, will be only 0.03 cfs for the 100-year, 24-hour design storm event. The pedestrian trail is therefore exempt from providing on- site detention. The amount of flood water storage volume will be increased as a result of the proposed channel excavation of material from within the FEMA floodplain by 4 acre-feet. The project will also increase the flood conveyance capacity of Springbrook Creek and reduce upstream flooding. 2) Could waste material enter ground or surface waters? If so, generally describe. Streams can serve as groundwater recharge sources or as groundwater sinks depending upon the underlying soil and the water levels in the stream and groundwater. Dewatering of the project area will be used to keep work areas dry. The groundwater may be rich in dissolved iron, which may be oxidized upon exposure to air and settle out of solution to produce a rust colored plume downstream of any groundwater discharge point. This will temporarily reduce the aesthetic value of the affected area which will return to original condition over time_ No new significant sources of waste from paved areas subject to vehicle traffic will be created. Motorized traffic is not permitted on the proposed pedestrian trail, except as needed for channel or trail maintenance. Because maintenance will be necessary infrequently, the waste material associated with vehicular use will not be significant. Although the project is within an area designated as having surficial aquifer susceptibility, it is not regulated by the City's aquifer protection ordinance. No significant increase in groundwater recharge is expected because the membrane proposed for installation next to SW Oakesdale Avenue is an effective barrier. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any. Prior to any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. All ground water withdrawals are to be directed, if conditions permit, into the METRO sanitary sewer, temporary -12- settling pond, or other device to minimize the discharge of iron rich water into Springbrook Creek. • The contractor will be required to submit plans outlining the proposed sequence and timing of any surface water bypass for review by the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. The contractor shall provide a backup system for maintaining or supplementing the function of any water bypass should the primary diversion fail or function inadequately. The bypass must be capable of handing mainstream Springbrook Creek flows of a minimum of the 2-year recurrence interval or design storm, a flow of 455 cfs (R.W. Beck, 1991). The contractor is to submit an emergency monitoring and contingency plan for City and SCS review prior to construction within the channel. The plan will outline measures to implement for immediate stabilization of disturbed areas at risk to flow of water, should the bypass system 2-year design capacity be in danger of being exceeded. • See Section B.1.h. for other measures. 4. PLANTS a. Check or circle types of vegetation found on the site: X deciduous tree: alder, maple, aspen, other evergreen tree: fir, cedar, pine, other _X_ shrubs g rass pasture crop or grain _X_ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other water plants: water lily, eel grass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered? The entire area of channel and pedestrian trail construction will be cleared of existing vegetation. C. List threatened or endangered species known to be on or near the site. None known. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: The proposed project contains both wildlife and fish habitat improvements. For fish habitat both banks of the open, low flow channel will be planted with Bankers dwarf willows on 2-foot centers. Two wildlife areas are also to be established. Three hundred shrubs will be planted. The shrub type will be Pacific Serviceberry, Tall Oregon Grape, Rodosier Dogwood, and Common Chokecherry. These two areas will have four rows parallel to the channel with groups of 3 to 5 plants of the same species staggered between the rows. The plants will be planted on 3-foot centers. -13- Following permanent seeding, a portion of the area outside of the low flow channel that was disturbed during construction will be covered by an excelsior blanket for erosion control and to create a moisture layer to aid in vegetative establishment. Permanent seeding consists of proportions of the following: ryegrass, white clover, creeping foxtail, fesque, and trefoil. The contractor will post a maintenance bond in accordance with City requirements as surety that any needed maintenance of installed improvements will be performed. 5. ANIMALS a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: Bird aw' eron eagle on bird�sther Mammals: deer, bear, elk, ve ther Fish: bass, almorl trou herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. None known. C. Is the site part of a migration route? If so, explain. Yes. Salmonids have been recorded migrating upstream at the Black River Pump Station. The fish counter at the pump station had recorded the following numbers for several years for the period from September through January. 1983-1984: 155 1986-1987: 82 1989-1990: 77 1984-1985: 119 1987-1988: 166 1990-1991: 69 1985-1986: 47 1988-1989: 95 1991-1992: 107 The Department of Fisheries has indicated that Springbrook Creek does support runs of coho salmon and other anadromous fish including steelhead, cutthroat trout and dolly varden trout. METRO in a 1990 report stated that the suitability of Springbrook Creek for salmonid spawning is poor and the rearing habitat is degraded. Upper tributary streams, such as Garrison Creek, may provide spawning and rearing habitat and Springbrook Creek provides the needed migration route. The proposed project will help to enhance the rearing habitat quality of Springbrook Creek. The existing channel will also provide off-channel flood storage that could be used as a resting area during time of high flows. d. Proposed measures to preserve or enhance wildlife, if any: • Construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. • Fish habitat components are included in the project design and consist of placing groups of three 24-inch diameter boulders in the low flow channel to create resting areas for migrating fish. Resting areas will also be created by placing boulders and rock rip rap around the boulders and up one of the side slopes of the low flow channel. A section of tree trunk with the root wad -14- exposed will be located in the channel bottom at a 30-degree angle to the cross section of the channel to provide additional resting and hiding area. There will be approximately eight of these in-stream habitat structures. • Plantings along the low flow channel as described in Section BA.d. will provide shading for migrating fish in the low flow channel. 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. Electricity is anticipated for a pedestrian crossing traffic signal at SW 16th Street. The need for a signal (which would be coordinated with the pedestrian trail) and its preferred location will be determined by the City Transportation Division as noted in Section A.11 as part of Transportation's planned study of the crossing alternatives. 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: Use of high efficiency traffic control luminaries will help keep signal operation energy needs and costs to a minimum. 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. Because the reach of Springbrook Creek within the project area is downstream of potential point and non-point pollution sources, the sediments in the stream bed may contain contaminants. Contaminants are known to be present in the Springbrook Creek system and have been monitored at several locations. One of the monitoring stations for the City's Black River Water Quality Management Plan (BRWQMP) was at SW 16th Street. Contaminant levels in sediments sampled at this station in 1992 were determined to be below Model Toxics Control Act Cleanup Regulation (MTCA) cleanup levels. These levels apply to sediments disposed of on land other than in a permitted landfill. Dredging or other construction disturbance as part of this project could cause contaminated sediments that may be in the project reach to be suspended and carried downstream. Contaminants that may be in the dredge spoils could also be a potential health risk if not disposed of properly. Although sampling at SW 16th Street indicated that special disposal of the sediments would not be required, SCS has contracted with Herrera Consultants to test a surface sample and a sample at one foot depth at a total of four locations within the project area. The field work was complete at the end of September and a report of the results is expected by the end of the year. 1) Describe special emergency services that might be required. -15- No special emergency services would be required. 2) Proposed measures to reduce or control environmental health hazards, if any: • Assess the Herrera sediment monitoring report once completed to determine if the pollutants are below levels requiring special disposal and/or if additional sediment testing is required. Additional testing may be necessary depending upon the requirements for use of the disposal site agreed upon by the site's owner. • If sediment monitoring results are found to exceed MTCA levels, obtain a permit from King County for disposal of the contaminated sediments at the Cedar Hills landfill permitted by King County. b. Noise 1) What types of noise exist in the area which may affect your project (for example:traffic, equipment, operation, other)? Traffic from 1-405 as well as surrounding arterial streets may be heard from the project site, but will not affect the project. Work will be conducted during the hours of peak noise generation from 1-405 and the surrounding arterial streets, and will not have a significant impact on the primarily commercial land use in the area. 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. Noise due to construction is expected for approximately four months from 7:00 am to 6:00 pm, five working days per week. If the contractor desires to work holidays, weekends, or other hours, permission shall be requested in writing subject to noise control conditions and requirements. 3) Proposed measures to reduce or control noise impacts, if any: Normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. 8. LAND AND SHORELINE USE a. What is the current use of the site and adjacent properties? The site is currently used as a stream corridor for conveying surface water runoff. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack site now being developed as the Boeing CSTC facilities, and slightly southeast of the METRO Wastewater Treatment Plant. The property to the north of 1-405 and west of the project channel is vacant land. -16- A single family dwelling with horse pasture is to the west of the channel, south of 1-405, and north of SW 16th Street. b. Has the site been used for agriculture? If so, describe. The Renton Green River Valley was historically used for agriculture and the project site and adjacent areas may have be used for such purposes, but not at the present time. C. Describe any structures on the site. Several concrete structures cross and border the project site. These include the 1-405 bridge and box culvert, the SW Grady Way box culvert, the SW 16th Street bridge, and the P-1 retaining walls. d. Will any structures be demolished? If so, what? No. e. What is the current zoning classification of the site? Portions of the site are zoned Medium Industrial (IM) and Commercial Office (CO). f. What is the current comprehensive plan designation of the site? Most of the site is designated Employment Area - Office, with the balance classified as Employment Area - Industrial. g. If applicable, what is the current shoreline master program designation of the site? The current designation of the project site is urban, pursuant to the Shorelines Master Program of the City of Renton (1990- SMP 5.04.03). h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. The site or portions of the site have been classified as within or containing the following environmentally sensitive areas: 100-year floodplain, wetlands and streams, surficial aquifer susceptibility, and seismic hazards. See Sections B.1 and B.3 for how the project will impact these areas. 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.- Not applicable. -17- I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project utilizes land area, which by its location and zoning designation, is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities consistent with the Shoreline Master Program goals and policies. The project increases the public accessibility to the shoreline, but preserves and improves the existing amenities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. 9. HOUSING a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. None. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. None. C. Proposed measures to reduce or control housing impacts, if any: Not applicable. 10. AESTHETICS a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s)proposed. Proposed concrete and rock gabion wing walls at the tallest height are approximately 10 feet high. b. What views in the immediate vicinity would be altered or obstructed? None, as the structures are located within the channel area below the adjacent surface grades. C. Proposed measures to reduce or control aesthetic impacts, if any: A habitat enhancement and planting plan will be implemented as part of the project to improve the aesthetics of this section of Springbrook Creek. 11. LIGHT AND GLARE a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Not applicable. b. Could light or glare from the finished project be a safety hazard or interfere with views? Not applicable. 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: Not applicable. 12. RECREATION a. What designated and informal recreational opportunities are in the immediate vicinity? Public trails along Springbrook Creek extend north and south of the project. Fort Dent Park, the Green River, and the Interurban trail are to the west and northwest. The Black River Riparian Forest lies to the north. 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: The project provides for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities of the Springbrook Creek shoreline area. 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. The 1979 SCS FEIS indicates the National Register of Historic Places stated there were no archaeological, historical, or unique properties of national significance within the project area. The Washington State Historic Preservation officer indicated four properties of historic significance are in the Green River valley, but not in the vicinity of the proposed project. To satisfy the requirements of Section 106 of the National Historic Preservation Act of 1966 and SCS regulations published in 7 CFR 656 on June 7, 1976, an archaeological reconnaissance of the ESGRW area was contracted in coordination with the National Parks Service with Grays Harbor College archaeologist, Lionel A. Brown. The investigation found that the potential is high -19- for the discovery of archaeological sites within the Green River area, but no previously unknown sites were found during the course of the survey. The report also determined that the ESGRWP project will have no adverse impacts upon the cultural resources within the watershed. This included the reach of the proposed project. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. Not applicable. C. Proposed measures to reduce or control impacts, if any: The contractor will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City of Renton, and the Washington State Historic Preservation Officer to determine the course of action. 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 project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Because of its limited access requirements and elevated grade access from 1-405 is not possible. SW Oakesdale Avenue drops below surrounding grade as it passes under 1-405 so access from this street is also not possible. The 1-405 interchange is west of the project area at West Valley Highway in the City of Tukwila. b_ Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? A public transit stop is located at the SW Oakesdale Avenue intersection with SW Grady Way within the project area. C. How many parking spaces would the completed project have? How many would the project eliminate? Not applicable. 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? Widening of the existing sidewalk and new sidewalk improvements are proposed at the southwest comer of the SW Grady Way and SW Oakesdale Avenue intersection to connect with the proposed pedestrian trail and to provide sufficient waiting area at the existing intersection crosswalk. A marked crosswalk and pedestrian crossing traffic control signal will be constructed at SW 16th Street to connect with the sidewalk and shoreline trail under construction as part of the Boeing CSTC project. These improvement are -20- proposed with either of the two options within the corridor (see Section A.11) under consideration. The pedestrian trail will extend north from the crosswalk location over to the existing channel to continue north following along its west bank. New sidewalk at SW 16th Street will be constructed at the north crossing waiting area only. No additional new sidewalk is proposed on the north side of SW 16th Street to discourage pedestrian use of the north side where there are no existing sidewalks or other marked crossings to travel to in the immediate vicinity. In accordance with the procedure described in Exhibit D, acquisition of a 15-foot permanent easement for the trail link is proposed to secure the necessary rights to allow public use. in accordance with the attachedThe easement will primarily follow the existing channel and minimize the area impact on the adjacent properties. Only the 80 foot segment directly north of SW 16th Street may have a greater land area impact if the crossing will be constructed at the Boeing CSTC driveway. This is because of its increased distance from the channel compared to the option of crossing opposite the shoreline trail south of SW 16th Street. e. Will the project use (or occur in the immediate vicinity ot) 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. Not applicable. g. Proposed measures to reduce or control transportation impacts, if any: The final crossing alternative and mitigation measures to be constructed will be determined by the City Transportation Division in a planned study of the crossing alternatives. For the options considered in this application the following measures are anticipated: • Provide a pedestrian traffic signal and marked crosswalk of SW 16th Street. • Construct signage in advance of the crossing to warn motorists of its location. • Modify the SW 16th Street and SW Oakesdale Avenue intersection to a three way stop to eliminate the free southbound right turn from SW Oakesdale Avenue onto SW 16th Street. 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. Yes. Limited maintenance (litter collection, sweeping) of the pedestrian trail will be required and is anticipated to be infrequent. This does not provide a significant increase in the scope of service already provided by the City Parks and Recreation Division. The maintenance could be performed by a volunteer task force. -21- Llmitied maintenance of the existing and proposed channel will be required and is also anticipated to be infrequent. Maintenance may include debris removal and vegetation management as necessary to ensure the safety of the public. This does not provide a significant increase in the scope of service already provided by the City Maintenance Division. b. Proposed measures to reduce or control direct impacts on public services, if any. None proposed. 16. UTILITIES a. Circle utilitie Currently available at the sit electric' natural a� water, efuse serve_ elephon anitaty sewer septic system other. Storm drainage. 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. The channel portion of the project is a storm drainage utility project designed to provide improved storm drainage service to the Springbrook Creek system and is described throughout this application. Storm drainage utilities are managed by local, state, and federal agencies. Electricity will be needed for temporary groundwater dewatering and may be needed for stream bypass construction activities. Puget Sound Power & Light provides electric service to the project area. C. SIGNATURE I, the undersigned, state that to the best of my knowledge the above information is true and complete. It is understood that the lead agency may withdraw any declaration of non- significance that it might issue in reliance upon this checklist should there be any willful misrepresentation;or willful lack of full-disclosure on my part. Proponent: r Y ,c .�, Cart c;= R-ErlTUN Name Printed: � v�L/7 Date: 1171 Z L-15 -22- Exhibit A PROJECT RELATIONSHIP WITH THE EAST SIDE GREEN RIVER WATERSHED PLAN The East Side Green River Watershed Plan (ESGRWP), also known as the Valley Drainage Study, has a long history dating back to the early 1960's when the local governments of Auburn, Kent, Tukwila, Renton, King County Conservation District, and King County requested federal flood assistance from the Soil Conservation Service (SCS) under the Watershed Protection and Flood Protection Act (Public Law 566). The SCS developed a work plan in 1965 which was approved by the United States Congress. This led to the construction of the Black River Pump Station (BRPS) in 1972. In 1972 the National Environmental Policy Act (NEPA) was enacted and it was determined that an Environmental Impact Statement (EIS) would be required prior to any future project improvements. A draft EIS issued in 1973 raised concerns regarding the environmental impacts posed by the plan. It was not until 1978 that a revised watershed plan was completed which provided for a reduced scope of work to more accurately reflect development trends and to address environmental concerns. A NEPA EIS was then prepared by SCS and approved at the federal level in 1979. Subsequent modifications to the 1978 revised watershed plan were finalized and approved by the local governmental sponsors along with an Environmental Mitigation Program in 1980. A 1981 amplification to the 1979 EIS was then prepared by the SCS to reflect the changes to the 1978 watershed plan. The plan consisted of constructing the P-1 Channel/P-9 Channel in the City of Renton and a series of channels in the City of Kent. The total plan consisted of approximately 11.1 miles of new channels with the P-1 Channel being the main channel with an average top width of 210 feet. In 1982 the local sponsors withdrew from the plan as a result of a disagreement over the equitable cost sharing for the local share of the plan construction cost. Following 1982, the City of Renton assumed lead agency responsibility.from King County. With assistance from SCS the City of Renton constructed the BRPS forebay, the P-1 Channel from the forebay to SW Grady Way, and the SW Grady Way box culvert. Efforts to continue construction of the channel improvements identified in the watershed plan from SW Grady Way to SW 43rd Street were halted when City review of the NEPA EIS determined that the document did not adequately evaluate the environmental impacts of the overall plan. However given that SCS support would be withdrawn if the City did not rely on the existing environmental documents, it was agreed, with Ecology approval, that the City proceed to adopt the NEPA EIS as a local SEPA document. The process to formally adopt the NEPA EIS as a local SEPA document began in 1988. The adoption process generated serious concerns and comments from various regulatory agencies, environmental groups, and citizens who questioned the adequacy of the original NEPA EIS. The City then suspended the adoption process and conducted an Adequacy Determination Study for the NEPA EIS. This study identified deficiencies in the NEPA EIS with respect to wetland impacts, impacts to streams, wildlife and fish habitat, and water quality. In addition, the existing hydrologic and hydraulic models were considered out of date due to changes in the drainage system and advances in modeling technology. EAST SIDE GREEN RIVER WATERSHED PLAN Concurrently with environmental review of the NEPA EIS, the 1-405 box culvert, the Oakesdale Avenue SW underpass, and the P-1 retaining wall projects were constructed in conjunction with the state's 1-405 HOV lane project. These projects were constructed without the corresponding channel improvement when concerns about the adequacy of the 1979 NEPA EIS halted efforts to continue construction of the channel improvements identified in the modified 1978 ESGRWP. The City elected to move forward with the construction of the 1-405 culvert and P-1 retaining walls because these structural improvements would have been much more expensive if not done in conjunction with the HOV project. Until the 1979 NEPA EIS was determined to be inadequate, the SW Grady Way to SW 16th Street channel project was considered an integral segment of the system of improvements identified in the modified 1978 ESGRWP. However, the SW Grady Way to SW 16th Street improvement is now proposed to be implemented separately, but concurrently, with the effort to identify and evaluate future flood control alternative projects south of SW 16th Street in an updated ESGRWP and EIS. The proposed channel project is then the final segment of channel improvements located north of SW 16th Street to be constructed in accordance with the modified 1978 ESGRWP and 1979 SCS NEPA EIS, as supplemented through the City SEPA process. Because the project and updated ESGRWP are independent and separate, approval of this project would not imply approval of any element of the updated ESGRWP effort. The proposed project impact evaluation and mitigation is considered independent from the updated ESGRWP because the project would not predetermine or depend on future improvements identified in the updated plan. The existing 1-405, SW Grady Way, SW 16th Street, and Oakesdale Avenue SW streets confine this project's segment of Springbrook creek to a narrow, defined corridor. Also, all downstream improvements and major structures necessary for the proposed project have already been permitted and constructed. The impact evaluation and mitigation for the proposed project are identified in the SEPA checklist. For the updated ESGRWP there are several options for the location of future improvements south of SW 16th Street, as the location for these improvements is not so limited by existing streets and other existing development. Any future proposed alignment must be evaluated for impacts and compared with other alternative alignments through the updated ESGRWP for their effect on environmental resources. The proposed project, however, does not predetermine, depend upon, or foreclose opportunities for a future connection between this project segment and any future ESGRWP improvement, that potential connection being clearly defined by the existing channel location as it passes under the SW 16th Street bridge. The City has made significant progress toward an updated ESGRWP, and is committed to completion of the plan effort. A portion of the work was to be completed though the Black River Water Quality Management Plan (BRWQMP) funded in part by a Centennial Clean Water Fund grant from Ecology. Ecology approval of the final BRWQMP plan has been received. Page 2 EAST SIDE GREEN RIVER WATERSHED PLAN Updated hydrologic and hydraulic models and summary reports, including a preliminary alternatives analysis have been sent to SCS for review. Work is in progress to address SCS comments on the models and to extend the period of simulation to include water years 1989-91, as well as the most recent information on regional storm water detention facilities, which were not included in the recent modeling work. Because of the major storm events in 1990-91, the flow predicted by the recent modeling work could increase up to 20%. The preliminary alternatives analysis will be reevaluated using the increased flows and the reports updated. The flood control alternatives will be finalized and integrated into an updated ESGRWP with other related information for SEPA review. Following environmental review final design can be completed. The first phase of construction of the improvements to be identified in the updated ESGRWP is expected to start in 1996. H:DOCS:94-002:SSW:ps Page 3 RAD01007 Watershed Black River King County -•�_Boundary Water ouality Management Plan • J Study Area j•' ........... Panther Lake 05 Kin Count Garrison i '�• S Renton Renton Creek I� Creek ' We Oft 0 Panther King County ,• i'—� Upper -- .� pang roo .. Volley reo N g� Kent S rin brook reek � aEastValle Road ; 1 3 Springbrook t Creek Ill .-------- ., !, ep to H1i11 67 Black River ee Kent ........ Pump Station rukh,pa 81 B1 -------- '� N � Kent ��•_._._.� Tukwila h / Kent Lagoons I-5 EAST SIDE CREEN RNEP WATERSHED NrS SouRcE: RW BECK k =r Q' r: !O Exhibit C N pump S>.4TIoN RENTON FORF SAY 1 as u South Renton Subbasin !-- Pumping 1 I OA--F5DI-LE Station rM l:T Ro} \ GRADy wA Basin Boundary Rolling \ sw Im St Hills Drain m Rolling Hills Subbasin ltJjl g �l P-9 Channel Pik �U Gee ,8 161 F '>_ Panther Creek Wetland Valley Subbasin i sw].h8C ell Sw431dSt Panther Creek Subbasin e / 167 8 ' r - S.1 sa,a S ••LEGEND ` \ � brookrin ------ Stream/Drainage Channel Sp g l; Springs ---- -- Storm Drain Pipe Subbasin 1 Subbasin Boundary 0 1000 2000 3000 SCALE IN FEET \) SovRCE HERY-kRA iN✓l/loNmF✓r� Black River Basin Water Quality Management Plan Exhibit D SW GRADY WAY TO SW 16TH STREET PEDESTRIAN TRAIL PROPERTY RIGHTS ACQUISITION PLAN The City of Renton is proposing to acquire a minimum 15-foot wide permanent easement along the west bank of Springbrook Creek between SW Grady Way and SW 16th Street. The purpose of the easement is to allow construction of a 12-foot wide asphalt trail for public use across the 1-405 corridor to connect with the public trails to the north of SW Grady Way and to the south of SW 16th Street. The plan for acquiring the needed property rights for the pedestrian trail is shown below. TASK DESCRIPTION ESTIMATED NO. COMPLETION DATE 1 Surveyor Services Contract. The City will execute a contract 1/94 with a surveyor from the City's approved annual consultants contract list. The surveyor will be responsible for preparing the legal descriptions and drawings needed for the property rights conveyance documents. 2 Research and Assessment. Preparation and review of 2/94 appraisal, title report, and hazardous assessment documents will be coordinated by the City Attorney, if required. 3 Conveyance Documents. Concurrently with Task 2 the City 3/94 Attorney will prepare the necessary legal documents for the property rights transfer. 4 Negotiations. The City Attorney will coordinate negotiations 5/94 with the grantors. If, in a reasonable amount of time, agreement cannot be reached upon a reasonable settlement, then negotiations will be halted and condemnation proceedings initiated. 5 Condemnation. The City Attorney will prepare the necessary 10/94 documents, obtain Council approval by ordinance of the condemnation, and carry out condemnation proceedings, if required. H:DOCS:93-1093:SS W:ps Exhibit E GLOSSARY OF TERMS Acre-foot - The volume of water, 43,560 cubic feet, that will cover an area of one acre to a depth of one foot Aquifer - A geological unit of porous and permeable rock or soil capable of. yielding usable amounts of water Base flood - The 100-year flood, or that flood having a one percent chance of being equaled or exceeded in any given year Base flow - The water that flows in a stream in the absence of rainfall-supplied runoff water (the source of base flow may be lakes, snowmelt, or discharge of ground water into the stream) Best management practices (BMPs) - Structural or nonstructural controls used to treat urban stormwater runoff Contaminant - Any hazardous substance that does not occur naturally or is found at concentrations greater than natural background levels Design storm - A rainfall event of specified size and frequency (for example, a storm that occurs only once every 10 years) that is used to calculate runoff volume and peak discharge rate Flood, base - The 100-year flood, or that flood having a one percent chance of being equaled or exceeded in any given year Flood fringe - That portion of the floodplain not including the floodway that is generally associated with slow-moving or standing water Floodplain - The total area of the floodway plus the flood fringe subject to inundation by the base flood Floodway - The channel of a stream and any adjacent floodplain areas that, according to the applicable flood hazard regulation, are reasonably required to convey the base flood flow and must be kept free of encroachment so that the base flood can be carried without substantial increase in flood height Gabion - A wire basket or cage filled with rock used as a.protective facing layer or structure to prevent soil erosion or embankment sloughing Ground water - Water stored beneath the surface of the earth, filling pores in soil, sand, or gravel; ground water is supplied by the seepage of rainwater, snowmelt, and other surface water into the soil (ground water discharges into lowland streams to maintain their base flow) Habitat - The physical and chemical environment that provides all of the basic requirements for life and enables an organism to successfully complete its life cycle (the habitat includes food, shelter, and other elements such as oxygen and temperature) Headwater stream - A stream forming the source of another larger stream Hydrology - The science dealing with the properties, movement, and effects of water on the earth's surface, in the soil and rocks below, and in the atmosphere Impervious area - Impermeable surfaces, such as pavement or rooftops, that prevent the infiltration of water into the soil Nonpoint Source Pollution - Pollution that enters a water body from diffuse origins on the watershed Point Source Pollution - Pollution that enters a water body from pipe or channel conveyance Refusal - The point in the driving of a piling at which the effort needed to drive the piling deeper becomes prohibitive Rip Rap - A facing layer or protective mound of rock placed to prevent erosion or sloughing of a soil due to the flow of surface and stormwater runoff Riparian zone - A relatively narrow strip of land that borders a stream or river Salmonids - Salmon and trout species of fish Sediment - Minerals and organic material suspended in or. settling to the bottom of surface water bodies (certain contaminants tend to collect on and adhere to sediment particles) Sheet flow - Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel Storm flow - The portion of flow that reaches the stream shortly after a storm event Surface water - Lakes, rivers, ponds, streams, inland waters, saltwaters, and all other watercourses Surficial Aquifer Susceptability - A index used to rank the potential for contaminants to infiltrate through the soil into an aquifer near the ground surface Suspended solids - Particles, both mineral (clay and sand) and organic (algae and small pieces of decomposed plant and animal matter) that are suspended in water and transported in stream flow Tightlining - The piping of urban runoff to protect easily eroded stream channels from the effects of high flow peaks Turbidity - A measure of water clarity based on cloudiness caused by the suspension of minute particles, usually algae, silt, or clay Water quality criteria - Specific levels of water quality that are expected to render a body of water suitable for its designated use; the criteria are based on specific pollutant properties and levels that would make the water harmful if used for drinking, swimming, farming, fish production, or industrial processes Watershed - The land area, defined by topographic divides, that drains into a stream Wetland - A habitat where the influence of surface water or ground water has resulted in development of plant or animal communities adapted to aquatic or intermittently wet conditions; wetlands include tidal flats, shallow subtidal areas, swamps, marshes, wet meadows, bogs, and similar areas Wing Wall - A retaining wall adjoining and extending from a bridge abutment, box culvert exterior wall, or similar structure that is used to retain the soil embankment associated with that structure Source: Renton, City of. May 1993. Black River Water Quality Management Plan. Prepared by R. W. Beck & Associates and Herrera Environmental Consultants. Seattle, WA H:DOCS:94-003:SSW:ps SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET LAND CLEARING AND TREE CUTTING ORDINANCE VARIANCE JUSTIFICATION Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 Land Clearing and Tree Cutting Ordinance Variance Justification LAND CLEARING AND TREE CUTTING ORDINANCE VARIANCE JUSTIFICATION A. Justify that the applicant suffers undue hardship and the variance is necessary because of special circumstances applicable to subject property, including size, shape, topography, and location or surroundings of the subject property; and the strict application of the Building & Zoning Code is found to deprive subject property owner of rights and privileges enjoyed by other property owners in the vicinity and under identical classification. The proposed project includes work within 25 feet of the ordinary high water mark of a segment of Springbrook Creek from SW 16th Street to SW Grady Way. However, Section 4-9-5.D of the Land Clearing and Tree Cutting Ordinance states, "No tree cutting or land clearing is permitted within twenty five feet (25') of any shoreline area, within twenty five feet (25') of the ordinary high water mark of creeks, in a wetlands area, or on parcels where the predominant slope or individual slope is in excess of forty percent (40%) except enhancement activities." The proposed project does not qualify as an exempt enhancement activity according to the definition in Section 4-9-3 of the Ordinance. Therefore, a variance is requested because portions of the project are within 25 feet of the sensitive areas listed in Section 4-9-5.D. . , The project suffers undue hardship because strict application of the Ordinance would prohibit any regional flood control project involving work within a creek, wetland, or shoreline needed to mitigate the expected cumulative effects of increased runoff volumes or flows to that sensitive area. These cumulative effects are primarily due to increases in impervious land area through development upstream, which if unmitigated, will .increase flooding, erosion, sedimentation, and other related environmental impacts and costs in downstream streams and wetlands. Similarly, the Ordinance would prohibit regrading of a segment of the existing stream bank within the proposed project area that has been eroded to a near vertical slope and is therefore unstable. Strict application of the Ordinance, therefore, inhibits management of the City's stormwater and related environmental resources necessary to promote the public health, safety, and general welfare of the citizens of Renton. B. Justify that the granting of the variance will not be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity and zone in which subject property is situa ted. Soil erosion could occur in connection with variance approval, since the entire area of the channel and pedestrian trail construction will be cleared of existing vegetation. Shoreline anchoring provided by the riparian trees, shrubs, and grasses will be temporarily lost. Erosion that could occur during rain and/or wind storms during the construction phase of the project will be minimized and is not expected to be materially detrimental with mitigation. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. 1 Land Clearing and Tree Cutting Ordinance Variance Justification The riparian vegetation to be removed under the authority of the variance is not diverse habitat or of significant structure. The trees to be removed are small and, at generally 6" in diameter, are the minimum size regulated under the ordinance. Removal of the trees and other riparian vegetation will be mitigated by providing surface cover protection to disturbed areas immediately upon achieving final grade or as conditions warrant. The project design includes a combination of plantings, rip rap, and erosion control blankets to minimize the erosion potential during and after construction. The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and washpads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. The project does not propose any improvement in the floodway that will increase the risk of flooding upstream of the project area. Instead the project removes restrictions from the floodway and reduces the risk. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of an existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. Due to restricted access requirements and the elevated grade of 1-405, vehicular access to the project site from 1-405 is not possible. Access to any portion of the project area from SW Oakesdale Avenue is also not possible because it drops more than 12 feet below surrounding grade as it passes under 1-405. Access is not possible from SW 16th Street or SW Grady Way to the project area east of the existing channel because of the depth and sensitive nature of the existing channel would restrict crossing opportunities. Because of this limited access to the project area, the proposed channel utilizes land area which is of no commercial use, but can be enhanced to provide a riparian corridor for fish and wildlife habitat. Use of the land within the project area is also limited by its proximity to the existing Springbrook Creek channel and the associated setback provisions of City Codes for any development along that channel. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicle use is expected to be infrequent and so the waste material.associated with vehicular use will not be significant. Vegetation removed for the trail construction will be restored as nearly as practicable to original condition as found immediately before commencement of the work. The potential for soil erosion associated with any clearing of vegetation for the trail as authorized by the requested variance will be minimized and mitigated as noted above for the channel portion of the project. 2 Land Clearing and Tree Cutting Ordinance Variance Justification C. Justify that approval shall not constitute a grant of special privilege inconsistent with the limitation upon uses of other properties in the vicinity and zone in which the subject property is situated. Approval does not constitute a grant of special privilege because others may include a regional flood control improvement use or facility in a project proposal. D. Justify that the approval as determined by the Hearing Examiner is a minimum variance that will accomplish the desired purpose. Granting of the variance provides relief from the provisions of Section 4-9-5.D that would prohibit land clearing and tree cutting associated with the proposed project. Other provisions of the Ordinance still apply. H:DOCS:93-007:SSW:ps 3 SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET PROJECT NARRATIVE Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 PROJECT NARRATIVE Project name: Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street Size and location of the project: The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. I- 405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Exhibit C. The project area is approximately 3-1/4 acres. Current use of the project site and adjacent properties: The existing Springbrook Creek channel that flows through the project area is best defined as a medium utility use and with adoption of the Interim Zoning Code has become an existing non- conforming use. This reach is the only outlet for a 22 square mile tributary.drainage area and cannot be abandoned, but will remain in use. The new channel segment to be constructed with the proposed project, which is adjacent to and includes portions of the existing channel, will create additional medium utility use between the existing channel and the 1-405 Oakesdale Avenue SW underpass. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. 1-405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack site now being developed as the Boeing CSTC facilities, and slightly southeast of the METRO Wastewater Treatment Plant. The property in the project area to the north of 1-405 and west of the project channel is vacant land, as is the property south and east of SW 16th Street. A single family dwelling with horse pasture is to the west of the channel, south of 1-405, and north of SW 16th Street. Nature of the existing shoreline: The reach of Springbrook Creek within the project area is an open channel which drains approximately 22 square miles of pervious and impervious land area from Kent, Tukwila, King County, and Renton. Surface water runoff reaches Springbrook Creek from these areas by overland flow or from a system of culvert and open channel point discharges along its length. Springbrook Creek flows north to join the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. The entire project is within 200 feet of Springbrook Creek. Springbrook Creek, through the project area, is designated a Shoreline of the State by the Department of Ecology, which determined that the mean annual flow of the creek in the area of the project was equal to or greater than 20 cubic feet per second (cfs). The current Shoreline Master Program designation of the project reach is urban (1990 - SMP 5.04.03). The entire project area also lies within the 100-year floodway and 1 floodplain according to Federal Emergency Management Agency Flood. Insurance Rate Map 530033CO453D dated September 29, 1989. The FEMA Flood Insurance Study September 29, 1989 regulatory base flood (100-year) water surface elevation in the reach is 16.4 feet NGVD at SW 16th Street. The existing Springbrook Creek channel, including the reach in the project area, has been extensively modified and disturbed by dredging and vegetation management activities performed by adjacent land owners and Drainage District No. 1 . In a June 1, 1989 inventory by SCS, the existing channel was noted to have open water approximately 15 to 20 foot wide with 2 to 3 feet .of woody and herbaceous vegetation on each side of the channel. The existing channel under I- 405, however, has been severely eroded by flood waters and disturbed by subsequent shoreline anchoring efforts by the Department of Transportation under 1-405. The significant channel erosion and sedimentation result in low quality fish habitat. A wetland inventory of the proposed project area was conducted on March 1, 1993. Eight sites were sampled and described. Only the southern 1-405 roadside drainage ditch was identified as a wetland using the methods of the Corps of Engineer's 1987 Wetland Delineation Manual and the 1989 Federal Manual for Identifying and Delineating Jurisdictional Wetlands. Two delineation methods are required because Springbrook Creek through the project area is not only under local jurisdiction, as defined by the 1989 Manual, but is also subject to the jurisdiction of the Federal Clean Water Act, Section 404, administered by the Corps, as defined by 1987 Manual. The wetland (Wetland A) is linear in shape and approximately 0.01 acre in size per 100 lineal feet of ditch. Because of its size, type, location adjacent to 1-405, and history of disturbance the wetland is given a low quality, Category 3 rating according to the City's Wetlands Management Ordinance. Proposed construction dates and phasing: Construction is anticipated to extend from late May to mid-October 1994. A total of 95 working days is anticipated for the project as follows: Mobilization: 10 working days Construction: 80 working days Cleanup: 5 working days Any construction within the existing channel will be allowed to occur during the summer months of the Washington State Department of Fisheries "window" from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. The contractor will prepare a construction mitigation plan, outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. City of Renton approvals or permits needed for the project: Shoreline Substantial Development Permit Conditional Use Permit Fill and Grade Permit Fill and Grade License/Construction Permit Land Clearing and Tree Cutting Permit Variance Site Plan Approval 2 Existing improvements and project description: The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of 'the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way, the SW Grady Way and 1-405 box culverts, the P-1 Channel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of .this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P- 1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide. The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the 1-405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Fill blocking the SW Grady Way box culvert would also be 3 removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Because of its limited access requirements and elevated grade access from 1-405 is not possible. SW Oakesdale Avenue drops below surrounding grade as it passes under 1-405 so access from this street is also not possible. Maintenance vehicle use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80 feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation Division in a planned study of the crossing alternatives. No views will be obstructed as a result of the proposed project, as the improvements are located within the channel area and are at or below adjacent top of bank grades. Purpose, type, and approximate quantities of grading proposed: A low flow channel will be constructed in the main channel, connecting with the low flow cells of the 1-405 and SW Grady Way box culverts. The low flow channel will have a 12-foot bottom width and 3 horizontal to 1 vertical side slopes. The overall top width of the low flow channel will be 27- feet. The main channel, including the low flow channel, averages 65-feet in width. To construct the proposed channel, the existing material necessary to achieve the proposed channel section subgrade will be removed. Subgrade is generally 1 .5-feet below the proposed finish grade, with a portion of the proposed channel directly adjacent to the Oakesdale Avenue SW underpass and underdrain system over excavated to 5-feet below the proposed finish grade to allow placement of' a watertight PVC membrane. The underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, must be protected from the short-circuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. To prevent this piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the membrane will be connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This 4 increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. The use of sheet piling driven into the channel bottom to lengthen the flow path was also considered, but was not selected because the piling may reach refusal too soon to provide effective protection. The total amount of excavation is estimated to be 15,700 CY. A total of 3 1/2-feet of fill material will be placed on the membrane to achieve subgrade. To reach finish grade on a portion of the channel, including the low flow channel, a total of 1/2-foot of sandy filter material and 1-foot of clean, loose rip rap will be placed on the subgrade. Other areas of the channel not receiving rip rap that are subject to potential erosive flows will be brought to finish grade with fill material and overlain with an excelsior blanket. This will protect the exposed soil and allow vegetation to become established to further protect against erosion. Excavation is also proposed to allow for placement of concrete wing walls on the west side of the I- 405 and SW Grady Way box culverts and a gabion wall north of the SW 16th Street bridge. The west side of the proposed and existing channel between SW Grady Way and 1-405 will be graded to a stable 2 horizontal to 1 vertical slope and a 1-foot depth of rip rap on 1/2-foot depth of filter material will be placed to protect against future erosive flows. The total estimated quantity of fill for the channel work is 8100 CY, including filter material and rip rap. Construction of the pedestrian trail shown in the plans will require an estimated 500 CY of fill to achieve subgrade. Fill material will be well graded sand to silty sand. The material will be from an approved gravel mining site and will arrive to the site via 1-405, SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. The specific source of the fill material and haul route is unknown at this time, but will be provided as a part of the final construction management plan, and will be submitted for approval to the City Development Services Division. Special plans to be prepared: Erosion control plan. Before any construction activity occurs, a pre-construction meeting with the contractor will be held with the project engineer and the City. Prior to the meeting, the contractor shall provide to the City and Engineer an erosion control plan for review and approval. The plan shall be based on the King County Surface Water Design Manual, as adopted by the City of Renton, proper construction practices, and any measures detailed in the contract plans and specifications. The contractor will also be responsible for addressing any state and federal permit conditions required for the project. All required sedimentation/erosion control facilities must be constructed and in operation prior to clearing and/or other construction to minimize discharge of sediment laden water from the project site. The implementation, maintenance, replacement, and additions to control facilities will be the responsibility of the contractor. As construction progresses and unexpected or seasonal conditions dictate, the contractor shall anticipate that more erosion and sedimentation control facilities will be necessary to insure complete siltation control on the project site. It shall be the obligation and responsibility of the contractor to revise or modify the erosion control facilities to meet any new conditions that may be created by construction activities and to provide additional facilities, over and above minimum requirements, as may be needed to protect adjacent properties and water quality of the receiving drainage system. 5 Construction mitigation plan. Prior to the preconstruction meeting the contractor shall also provide to the City and Engineer a construction mitigation plan outlining the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. Dewatering plan. Ground water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Geotechnical reports for other projects in the project area describe ground water levels at relatively shallow depths. Because of potentially high ground water conditions the contractor for the proposed project will be required to determine if conditions at the time of construction are low enough to allow construction. If not, the contractor will be required to construct well points at strategic locations in the project area to draw down the water table sufficiently. Before any dewatering the contractor will be required to submit a dewatering plan for City and SCS review. The amount of ground water to be withdrawn is a function of the soil conditions, water table elevation, required drawdown, and wellpoint location and depth. Therefore, the number of wellpoints and the amount of groundwater that will be withdrawn cannot be estimated at this time. Springbrook Creek bypass plan. Springbrook Creek will be routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. This is necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. The sequence and timing of the any bypass is to be contractor determined, subject to the review of the City and SCS. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. It is anticipated that construction of the channel north and south of 1-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the weather conditions at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. Special site features: The site or portions of the site have been classified as within or containing the following environmentally sensitive areas: 100-year floods lain, wetlands and streams, surficial aquifer susceptibility, and seismic hazards. Seismic hazards. The City of Renton has mapped the Green River Valley area as a seismic hazard, due to the liquefaction potential of the unconsolidated sands present in the Valley soil profile. Even without the proposed project having been constructed, the adjacent structures are subject to liquefaction induced settlement. However, these structures were designed to accommodate the proposed channel improvement. The construction of the project is therefore not anticipated to impose unanticipated risks to structures in the project area due to seismic ground movement and acceleration. The 1-405 bridges in the vicinity are constructed on piling and other structures are founded on broad footings to reduce the risk of settlement due to liquefaction. 6 Surficia/aquifer susceptibility. Although the project is within an area designated as having surficial aquifer susceptibility, it is outside of the City's aquifer protection zones and is not regulated by the City's aquifer protection ordinance. No significant increase in groundwater recharge is expected because the membrane proposed for installation next to SW Oakesdale Avenue is an effective barrier. H:DOCS:94-006:SS W:ps 7 SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET ADMINISTRATIVE CONDITIONAL USE REQUEST JUSTIFICATION Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 Administrative Conditional Use Request Justification ADMINISTRATIVE CONDITIONAL USE REQUEST JUSTIFICATION The use of the area effected by the proposed project is best defined as "medium utility" because the channel improvement will serve to convey storm drainage from the sub-area of the City within the Black River Basin. Portions of the project site are zoned Medium Industrial (IM) and Commercial Office (CO). According to the Interim Zoning Code (RMC 4-31), an administrative conditional use is required for a medium utility use in the IM (RMC 4-31-1 1.2) and CO (RMC 4-31-16) zones. It is recommended that an administrative conditional use be granted for the reasons following. A. Comprehensive Plan: The proposed use shall be compatible with the general purpose, goals, objectives, and standards of the comprehensive plan, the zoning ordinance, and any other plan, program, map, or ordinance of the City of Renton. 1. Comprehensive Plan. The project is consistent with the overall goal of Chapter 8, Environment, of the Interim Land Use Element of the Comprehensive Plan (Renton, 1993), "Continued protection of Renton's natural systems, natural beauty, and environmental quality. The project will provide increased floodwater conveyance through the existing reach that is too narrow for adequate floodwater passage. The existing channel is also too confined and may not be widened without undermining the existing pile supports for the 1-405 bridge, which are not spaced sufficiently far apart to allow the existing channel under the bridge to be enlarged. An additional 4 acre-feet of floodwater storage,will be provided. These benefits add to the level of flood protection provided upstream of the project area. The project is designed for multiple use and benefit with the inclusion of elements such as: 1) fish and wildlife habitat plantings and structures, 2) low flow fish passage channel, 3) regrading and armoring of existing severely eroded stream banks, 4) high flow conveyance and storage within the new and existing channels for increased flood protection, 5) preservation of the existing channel for off-stream fish and wildlife habitat, and 6) inclusion of a pedestrian trail link for recreational opportunities and public access to the shoreline. Because of these multiple uses and benefits, the project is also consistent with many of the objectives and policies of Chapter 8, Environment, of the Interim Land Use Element. Policy EN-4.1: "Manage water resources for multiple uses including recreation, fish and wildlife, flood protection, erosion control, water supply, energy production, and open space"(emphasis supplied). Policy EN-5.2: "Degraded channels and banks should be rehabilitated by public programs and new development" (emphasis supplied). Policy EN-8.1: "Maintain and enhance natural drainage systems to protect water quality, reduce public costs, and prevent environmental degradation." Policy EN-8.2: "Preserve natural surface water storage sites that help regulate service flows and recharge groundwater" (emphasis supplied). Objective EN-9.0: Provide a storm and surface water control and drainage system capable of preventing threats to life, property and public safety during a 100 year flooding event." 1 Administrative Conditional Use Request Justification Policy EN-9.4: "Manage the cumulative effects of storm water though a combination of engineering and preservation of natural systems." Objective EN-10.0: "Provide for, and work toward, a regional approach to stormwater management programs." The project is a joint effort of the City of Renton and the U.S.D.A. Soil Conservation Service (SCS). The project is approximately 75% funded by SCS through the Watershed Protection and Flood Protection Act (Public Law 566). Objective EN-14.0: "Protect and enhance wildlife habitat through the City." Policy EN-17.6: "Incorporate design elements which preserve and enhance the natural drainage system into developments in an effort to control erosion and sedimentation." 2. Zoning Ordinance. The project is also compatible with applicable development standards within the IM and CO Zones. a. Landscaping. The wildlife planting proposed with the project covers a 3200 square foot area, in satisfaction of the 2% landscaping requirement in the Development Standards section of the IM zone (RMC 4-31-1 1.2.D). b. Sensitive Areas. The project is consistent with the applicable requirements of the Flood Hazards and Landscaping sections of the Zoning Ordinance as follows: 11 Flood Hazards (RMC 4-31-31). "Encroachments...and other development...shall not result in any increase in flood levels during the occurrence of the base flood discharge" (Section G3a). The project will not only meet this requirement, but exceed it, by reducing the flood levels upstream of the project. 2) Landscaping (RMC 4-31-34). "Any development in the Green River Valley shall provide a minimum of two percent (2%) of the total site for landscaping suitable to wildlife habitat" (Section F2). The wildlife planting area proposed for the project meets this 2% requirement. "The faces of cut and fill slopes shall be developed and maintained to control against erosion. This control may consist of effective planting. Where necessary...rip .rap or other devices or methods shall be employed..." (Section F4). Before any construction activity occurs, a pre-construction meeting with the contractor will be held with the project engineer and the City. Prior to the meeting, the contractor shall provide to the City and Engineer an erosion control plan for review and approval. The plan shall be based on the King County Surface Water Design Manual, as adopted by the City of Renton, proper construction practices, and any measures detailed in the contract plans and specifications. The contractor will also be responsible for addressing any state and federal permit conditions required for the project. Prior to the preconstruction meeting the contractor shall also provide to the City and Engineer a construction mitigation plan outlining the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul 2 Administrative Conditional Use Request Justification route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. All required sedimentation/erosion control facilities must be constructed and in operation prior to clearing and/or other construction to minimize discharge of sediment laden water from the project site. The implementation, maintenance, replacement, and additions to control facilities will be the responsibility of the contractor, subject to the approval of the City and project engineer. Any construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. As noted above the contractor will prepare a construction mitigation plan outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. A 1-foot deep rock rip rap protective layer will be placed over disturbed areas under and adjacent to the SW 16th street bridge, the low flow channel area, and a portion of the west bank of the channel between 1-405 and SW Grady Way. The rip rap on the west bank area will be loosely placed, covered with topsoil, and seeded. A 0.5-foot deep layer of filter material will be placed under the rip rap to prevent washing of any finer material from the underlying soil. Wire mesh gabions will be placed along a portion of the west bank just north of the SW 16th Street bridge to protect against erosive flows. A layer of filter material will be placed behind the gabions to prevent washing of finer material from the protected bank. Disturbed areas will be seeded immediately following construction. Seeding shall be started as soon as definable segments of the excavated channel are completed as determined by the Engineer. Permanent seed mixtures shall be applied between April 1 to October 15. Winter seeding shall be applied outside the permanent seeding dates as needed, and followed with permanent seeding the next spring as approved by the Engineer. Following permanent seeding, a portion of the area outside the low flow channel that was disturbed during construction will be covered by an excelsior blanket for erosion control and to aid vegetative establishment. As construction progresses and unexpected or seasonal conditions dictate, the contractor shall anticipate that more erosion and sedimentation control facilities will be necessary to insure complete siltation control on the project site. It shall be the obligation and responsibility of the contractor to revise or, modify the erosion control facilities to meet any new conditions that may be created by construction activities and to provide additional facilities, over and above minimum requirements, as may be needed to protect adjacent properties and water quality of the receiving drainage system. 3. Shoreline Master Program. The multiple uses and benefits included with the proposed project noted in Section Al above are also consistent with the following goals and policies of the Shoreline Master Program. 3 Administrative Conditional Use Request Justification "Preference should be given to those uses or activities which enhance the natural amenities of the shorelines and which depend on a shorelines location or provide public access to the shorelines" (Section 4.01 .02.A.2). The project must be constructed at the proposed location because the existing 1-405, SW Grady Way, SW 16th Street, and Oakesdale Avenue SW streets confine Springbrook Creek within the project area to a narrow, defined corridor. An alternative location for the new channel is not available outside of the proposed project area. Also, all downstream improvements and major structures necessary for the proposed project have already been permitted and constructed. The pedestrian trail component of the project provides public access to the shoreline. "Existing natural resources should be conserved" (Section 4.02.02.A). The existing channel under 1-405 will be preserved to provide off-stream fish and wildlife habitat. The channel will also provide 4 acre-feet of additional flood water storage, as well as additional conveyance capacity. The plantings and structural features described in Section Al above also further implement this policy. "The City of Renton should take aggressive action with responsible governmental agencies to assure that the discharges from all drainage basins are considered an integral part of shoreline planning" (Section 4.02.02.C). The proposed project will be constructed with the assistance of SCS and is an essential element of a regional system of storm drainage facilities that convey basin discharges and provide flood control protection to the public. "Increase public accessibility to shorelines, and preserve and improve the natural amenities" (Section 4.04.01). "Pedestrian and bicycle pathways...should be developed" (Section 4.06.02.C). The pedestrian trail will provide public access to the shoreline in the project area. 4. City of Renton Master Trails Plan. "Address 'micro' level trails and fill in gaps in existing trail patterns where appropriate" (Policy 7). The project proposes a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south. This will complete a missing link segment of the Springbrook Valley Trail identified in the Master Trails Plan. B. Community Need. There shall be a community need for the proposed use at the proposed location. In the determination of community need, the Administrator shaf/consider the following factors among all other relevant information: 1. The proposed location shall not result in either the detrimental over-concentration of a particular use within the City or within the immediate area of the proposed use. The existing Springbrook Creek system is linear in shape and the land area currently subject to its use will not be significantly increased by the project or result in over-concentration of the use. The additional medium utility use to be provided by the proposed project is necessary to provide increased flood control protection to the public. 2. That the proposed location is suited for the proposed use. The existing Springbrook Creek channel that flows through the project area is best defined as a medium utility and with adoption of the Interim Zoning Code has become an existing non- conforming use. This reach is the only outlet for a 22 square mile tributary drainage area and 4 Administrative Conditional Use Request Justification cannot be abandoned, but will remain in use. The new channel segment to be constructed with the proposed project, which is adjacent to and includes portions of the existing channel, will create additional medium utility use between the existing channel and the 1-405 Oakesdale Avenue SW underpass. The new channel utilizes a narrow strip of land area, which by its location (lack of access) and zoning designation (setback requirements) is of no commercial or industrial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. C. Effect on Adjacent Properties: The proposed use at the proposed location shall not result in substantial or undue adverse effects on adjacent property. The proposed project is a regional flood control improvement designed to increase the level of flood control protection currently provided by the existing channel for all property upstream of the project reach. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed. The project utilizes land area, which by its location and zoning designation, is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the 1-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south which will provide increased recreational and educational opportunities consistent with the Shoreline Master Program goals and policies. The project increases the public accessibility to the shoreline, but preserves and improves the existing amenities. Acquisition of a permanent easement from adjacent property owners for the trail is proposed to secure the necessary rights to allow public access. A reasonable settlement with the property owners for the trail easement rights will be made. H:DOCS:94-005:SSW:ps 5 SPRINGBROOK CREEK/P-1 CHANNEL IMPROVEMENT PROJECT SW GRADY WAY TO SW 16TH STREET STORM DRAINAGE REPORT Planning/Building/Public Works Department Gregg Zimmerman, Administrator Prepared by: Surface Water Utility Division Scott Woodbury, Project Manager December 1993 A. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET The TIR worksheet for the project is attached (Attachment 1). B. PROJECT SUMMARY The project is linear in shape and is adjacent to, and includes portions of, a reach of Springbrook Creek that flows to the north. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Oakesdale Avenue SW underpass on the east. I- 405 runs east-west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack and slightly southeast of the METRO Wastewater Treatment Plant. The entire project is in the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M., in King County, Washington. See Attachment 3. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). Improvements which have been completed during this period include the Black River pump station forebay, P-1 Channel improvements from the forebay to SW Grady Way, the SW Grady Way and 1-405 box culverts, the P-1 Channel/Oakesdale retaining wall, and the SW 16th Street bridge. The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way (Sta 680+26.37) to SW 16th Street (Sta 670+76). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Attachment 2), directs flows north under the SW 16th Street bridge toward the 1-405 . box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. The channel improvement between Grady Way and SW 16th Street was not completed at the same time as the 1-405 box culvert because the channel improvement project was proposed to be implemented as part of another project, the overall P-1 Channel improvements identified in the modified SCS 1978 East Side Green River Watershed Plan (ESGRWP), rather than as a corollary project to the 1-405 box culvert. A review by the City of the.adequacy of the 1979 NEPA EIS to address the environmental impacts of implementing the modified 1978 ESGRWP identified that further study was needed before the P- 1 channel construction south of SW 16th Street could be done. This delayed construction of the Grady Way to SW 16th Street channel improvement .project. The City elected to construct 1-405 box culvert with the 1-405 HOV lane widening and the Oakesdale underpass projects, because it was determined uneconomical to construct the culvert at a later time. The proposed channel improvement project would remove the fill blocking the culvert and bring the 1-405 box culvert into service as originally intended by allowing flows to pass through it. Continuing downstream from under the 1-405 bridge, the flow is redirected to the northeast to pass through the SW Grady Way box culvert and on toward the Black River Pump Station forebay. Only three of the five cells of the SW Grady Way culvert are currently open because of the existing narrow inlet channel blocking the outer two cells. The project proposes to widen the inlet channel to fully utilize the full capacity of the existing Grady Way box culvert for flood control. 1 The channel reach between 1-405 and SW Grady Way is a source of downstream sedimentation due to erosion along the west bank of the reach. The project area provides minimal habitat for wildlife because the surrounding streets confine Springbrook Creek to a narrow, defined corridor disconnected from other habitat in the area. Shoreline anchoring work by the Department of Transportation under 1-405, significant channel erosion and sedimentation result in low quality fish habitat. The narrow existing channel_also affords little in-stream or off-stream shelter to migrating fish which the proposed project will provide. The proposed channel construction would begin immediately upstream of the SW 16th Street bridge and extend north along Oakesdale Avenue SW through the 1-405 box culvert to SW Grady Way. Fill blocking the 1-405 box culvert would be removed and Springbrook Creek flows directed through the 1-405 box culvert. Low flows and most of the high flows would pass through the new channel. A low flow channel to maintain fish passage is included in the design which would connect to one of the five bays of the 1-405 and SW Grady Way box culverts which have a lower bottom elevation than the other bays for fish passage. Upland fill blocking the SW Grady Way box culvert would also be removed. The existing stream channel adjacent to and under 1-405 would be preserved to convey some flows in larger storm events, provide needed flood storage, and create off-stream habitat for fish and wildlife use. The proposed project would provide many benefits including increased flow conveyance capacity and flood storage as well as alleviation of the existing erosion problem. The project completes the channel improvements for which the existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16th Street bridge capital improvements were designed and constructed. The project utilizes land area, which by its location and zoning designation is of no commercial use, but will be enhanced to provide a riparian corridor for fish and wildlife habitat. These improvements would also be beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the I-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will provide increased recreational opportunities. Acquisition of a permanent easement for the trail is proposed to secure the necessary rights to allow public access. Curb cuts at SW 16th Street and SW Grady Way will also allow access for maintenance vehicles on an as needed basis. Maintenance vehicles use is expected to be infrequent. The trail alignment from the south side of SW Grady Way to about 80 feet north of SW 16th Street follows along the top of the west bank of the existing Springbrook Creek channel. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor. The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered in this application are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City Transportation Division in a planned study of the crossing alternatives. The pedestrian trail will cross the south 1-405 roadside ditch which conveys runoff from a 11.3 acre drainage basin situated west of Springbrook Creek, north of SW 16th Street, and south of SW Grady Way (Attachment 4). A culvert sized to pass the 100-year, 24-hour design storm (see Section H) will be installed to enable the pedestrian trail to cross the ditch. 2 The findings of this drainage report are valid for a 12-foot wide pedestrian trail from SW Grady Way to SW 16th Street regardless of the alignment selected by the Transportation Division, provided it generally follows along the existing channel of Springbrook Creek. C. EXISTING AND PROPOSED DRAINAGE FEATURES The existing and proposed drainage features are described in Section B. D. CORE AND SPECIAL REQUIREMENTS Core Requirement #1. Discharge at the natural location. The discharge location will remain unaltered by the project. Core Requirement #2. Off-site Analysis Level 1. The project is adjacent to, and includes portions of, an existing reach of Springbrook Creek that flows north. Springbrook Creek joins the Black River in the Black River Pump Station forebay which is then pumped into the Green River. The Duwamish River, formed by the confluence of the Black and Green Rivers, flows northerly into the Elliott Bay of the Puget Sound. No problems associated with high flows/flooding are apparent in immediate area of the existing Springbrook Creek channel and Black River Pump Station forebay improvements downstream of the project area. Within the project area, a portion of the west bank of the existing channel north of 1- 405 has been eroded to a near vertical slope and is therefore unstable. This area will be graded to a more stable 2 horizontal to 1 vertical slope and protected with rip rap and vegetation. Studies have shown that Springbrook Creek has poorer water quality than many other urban streams in the area (Metro, 1990; City of Renton, 1993). Sediment deposits downstream of the project area appear to be accumulating. Sediment accumulations reduces available conveyance capacity and may eventually become a problem over time. Core Requirement #3. Runoff Control. The 0.03 cfs increase in pre-developed runoff condition for the 100-year, 24-hour design storm due to the project is less than the 0.5 cfs threshold increase for exemption from runoff control requirements. Therefore peak rate runoff control (detention) is not required as part of the project. The increase in runoff volume of 486 cf is insignificant compared to the 4 acre-feet increase in storage that the project will provide. See Attachment 5. Core Requirement #4. Conveyance System. Construction of the proposed project will reduce head loss in the project reach which will result in lowering the base flood water surface profile of the upstream system. The project will also allow higher flows to pass through the project reach to the downstream system and more fully utilize the capacity for which the downstream improvements were designed (R. W. Beck, 1991). 3 Core Requirement #5. Erosion/Sedimentation Control Plan. The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel will be kept to a minimum. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed soils should be applied during construction. Stabilized construction entrances and wash pads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. Special Requirements #1-#12. None of the special requirements apply to this project. E. On-site Detention Design Does not apply because the project is exempt from Core Requirement #3, Peak Rate Runoff Control. F. Biofiltration Design Does not apply because the project does not propose to construction more than 5,000 square feet of new impervious surface subject to normal vehicular use. G. Wet Pond Design Does not apply because the project will construct less than 1 acre of new impervious area. H. Conveyance Velocity Calculations The full flow velocity of the 24" concrete culvert selected for the south 1-405 roadside ditch for the 100-year, 24-hour design storm of 9.40 cfs is 3.0 fps. See Section I for the culvert sizing. I. Conveyance Capacity Calculations The objective of the culvert design is to minimize the head loss through the culvert for the 100- year, 24-hour design storm, which for the tributary basin of 11.31 acres was calculated to produce a peak rate runoff of 9.40 cfs in the post-project condition (Attachment 5). Because the ditch is deep at the culvert location, a 60' length is required in order for the ends of the culvert to protrude from the fill slopes extending from the grade of the proposed trail. An inlet invert elevation of 6 feet and an outlet invert elevation of 4 feet (NGVD 1929) was assumed based on the profile of the ditch invert. The culvert capacity was based on outlet control with the 100-year tailwater elevation of Springbrook Creek of 13 feet (R. W. Beck, 1992) and the sizing completed utilizing the nomograph included as Attachment 6. A 24" culvert was selected because its ability to conduct the design flow of 9.40 cfs, minimize any headloss, and maintain a 3 fps full flow velocity. See Section H for the full flow velocity check. 4 J. Level One Downstream Analysis See Section D, Core Requirement #2. List of Attachments Attachment 1. Technical Information Report (TIR) Worksheet Attachment 2. Watershed Map Attachment 3. Project Vicinity Map. Attachment 4. South 1-405 Roadside Ditch Tributary Basin Map Attachment 5. Peak Rate Runoff Calculations Attachment 6. Pipe Sizing Nomograph References Metro. 1990. Quality of local lakes and streams, status reports for 1988-1989. (Publication 167, Revision A.) Water Resources Section. Water Pollution Control Department. Seattle, WA. R. W. Beck and Associates. 1991. East Side Green River watershed plan, current condition document. Seattle, WA. Prepared for City of Renton, Renton, WA. 1992. East Side Green River watershed plan, hydraulic analysis report. Seattle, WA. Prepared for City of Renton, Renton, WA. Renton. 1993. Black River Basin water quality management plan. Prepared by R. W. Beck and Associates and Herrera Environmental Consultants in association with Jones & Stokes Associates, Inc. Seattle, WA. H:D0CS:94-004:SSW:ps 5 Attachment 1 Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PART I PROJECT OWNER AND PART 2 PROJECT LOCAMON PROJECT ENGINEER . . DESCRIPTION Project Owner C 1 4 Project NameS WR ,6("Jt Address Location 0vA^f Vr- Phone 2D(- " 2 55`1] Township 3 Project Engineer R Section Company Project Size S• -2 s AC Address Phone (," ` " 53 ZS Upstream Drainage Basin Size 0�o AC PART3 TYPE-OF PERMIT . oTHERPERmrrs ED Subdivision [::J DOF/G HPA ® Shoreline Management Short Subdivision Q COE 404 ( Rockery ® Grading [:1 DOE Dam Safety Structural Vaults Commercial 0 FEMA Floodplain Other Other ® COE Wetlands ® HPA PARr5 SITE COMMUNITY AND DRAINAGE Community Drainage Basin PARTS SlITIE CHARACTERISTICS 0 River ® Floodpiain ® Stream [3�< Wetlands L—J Cmcal Stream iieach L--J Seeps/Springs ' ED Depressions/Svales © High Groundwater Table Lake Groundwater Recharge Steep Slopes Other Lakeside/Erosion Hazard PART7 SOILS Soil Type Slopes Erosion Potential Erosive Velocities y2KAa LA"o ,=LrNr Sal(,H 7- Additional Sheets Attatched 1/90 RAD01007 '. ,,,,�-Watershed Black River King County ,.. t Boundary Water OuaRy Management Plan .•' • J Study Area •. ........_,,, •�' .............................ecw Panther Lake Qa r % 05 Kin Count Garrison i •' Renton Creek ,S�•• Renton reek We•ortds �-- Ponther C _ King County ' !� Upp e r ---.`; Sprang roo •'�� Volley rea N• 87 Kent �S rin brook ree T' '• nv` East Volley Road ; i 1 i Springbrook ' Creek t e to M}p 67 u W 1 6 ek r' Block River Ce Kent Ln Pump Stotion, rukh,;I 81 a Kent Tukwila " __ �•`�, N / Kent / Logoons EAST SIDE CREEN RNEP WATERSHED Nrs SouRcL: R_ AND AssoaA]M m .�..�� 0 3 N Attachment 3 N PUMP SrATlonl RE TON FOR F 8/w��J t South Renton Subbasin 00k r Pumping J caESDAIE Station �MErrzo) \ 6n'RADy wA Basin Boundary Rolling _ sW,w,SL Hits Drain Rolling Hills .� Subbasin J t P-9 CAanwf 181 I Panther Wetland Valley Subbasin i SW 341,si 1, - sw.w SL Panther Creek Subbasin m / 167 g LEGEND rin ------ Stream/DrainageS brook Channel ,�'� p g ;... g Springs Storm Drain Pipe ¢ Subbasln '° l Subbasin Boundary 0 1000 2000 JoOo •` SCALE IN FEET SOURCE :HEkZj�RA L.�vi��n,f•�r�� Black River Basin Water Ouality Management Plan - i i: 1 �'� r:����;�rr_r�: r_�� ��.tjis.•'.'�.i_�eS.:�R?iF!'�lei• S'euei' • .�_ r Attachment 5 Springbrook Creek/P-1 Channel Improvement Project SW Grady Way to SW 16th Street PRE-DEVELOPMENT AREA WEIGHTED RUNOFF COEFFICIENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN Lan d. ................ .................................. N. x"..". X: I ....... .......... um ..U, A. 00 laer Ur D 98 Pavements,Roofs 5.64 50% 48.9 Ur D 91 Compact Gravel 0.21 2% 1.7 Ur D 90 Landscape,Grass 5.46 48% 43.5 ......... ...... '0 ...... 94— ...1 .0 ... . .......... POST-DEVELOPMENT AREA WEIGHTED RUNOFF COEFFICIENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN i ht d ............... .... . .. Xbii 16 ...... Ur D 98 Pavements,Roofs 5.80 51% 50.3 Ur D 91 Compact Gravel 0.21 2% 1.7 Ur D 90 Landscape,Grass 5.30 47% 42.2 .. ..... . . .. ....................6........ .:............................. . ... .. ... .. ... q ........... HYDROGRAPH SUMMARY PRE-DEVELOPMENT AND POST-DEVELOPMENT SOUTH 1-405 ROADSIDE DITCH TRIBUTARY BASIN . ..... . ...... .................... ....... ...... ........ ......- . ......... ...... ... ..... ..... ................... -e U0,61.tatim yo .......24-11 "P. k*o*,-tfl "', - ...... 4 " A� . ........ . .. ................I............................... - . ........... _._0W'. ... ...... ...................... ............... .. ..... ............ .... ..... ........ ................... .......... ...................... .......................... ...... ........ ............. ...... ................ ... ........... .. ....................... 4 ft ....... ...... . . .. ......... ....... ... ......... ............ .. ........................... ... ................. ..... . .......... Pre-Development 9.37 133683 Post-Development 9.40 133197 Dtf#er— _.. ........... ange+ ::.�.,-",�;:��::�.-+,"�.':�::::::::: ... ....... nce0x h ....... Notes: 1. Soil groups determined from USDA SCS Soil Survey, King County Area, Washington, 1973. 2. Hydrologic groups determined from KCSWM Manual Figure 3.5.2.A. 3. Curve numbers determined from KCSWDM Table 3.5.2B. 4. Land use descriptions from City of Renton aerial photographs and Boeing CSTC drawings. i lt7D2oC,PA uuTPyi 06vb�ofr A.�/f HhOko(�f�PP Svc&, /oo-y2/ -zy- iT� ST�(�- P� - fj W W W S.C.S. TYPE-IA RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR), PRECIP(INCHES) N g g 100,24,3.90 _r ---------------------------------------------------------------------- v ae **** S.C.S. TYPE-IA DISTRIBUTION ******************** r r r ********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. ********* rrn o ---------------------------------------------------------------------- �4 ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 5.67,90.04,5.64,98,9.5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 11 .3 5.7 90.0 5.6 98.0 9.5 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) 9.37 7.83 133197 y/c� -2-*r H 2 S-To(L►,, Flisr- Uj���ME�T 49g 01r-o P-A?R Su M A/ yS.C.S. TYPE-lA RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 100,24,3.90 ---------------------------------------------------------------------- ******************** S.C.S. TYPE-IA DISTRIBUTION ******************** ********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. ********* ---------------------------------------------------------------------- ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 5.51,90.04,5.80,98,9.5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 11 .3 5.5 90.0 5.8 98.0 9.5 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) 9.40 7.83 133683 • �urJ�{N v6�d _ 7m 6 OF Ge0 Ct-oO MA i)OYJ A slur 2-06• 5HAi-r FWw + 1600 ' � „T r C�,,�J zov� ,,,,�Mr•�rr�rf(�ws+ S�Gv►nF,nl' A ZOO / <1 S fP ALr PAVIN(, Sr%FI f F�aw) Sa .r 0. OZ L7/fr / hS 0. 61� So - p. oZ Fr/Fl- / kc = vl Eh(L-r-J k Nf, sw�l,E W W W W W W =z N t1f N coo CGII.G(�L�TE T(:�✓E L -�I _r Dery 0.8 o.s v Z o .7`- ` L) = o_ '1z o,ot �2v� , "-2 .-7 M,,j ee A n to O. S o.7 2 0. O y er C4� l O /Z - `o /-�TT/� Gt1MEuT(c KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL FIGURE 4.3.5E HEAD FOR CULVERTS (PIPE W/"n" =0.012), FLOWING FULL WITH OUTLET CONTROL 2000 —� H HWI I —} ko d a Z W Slope Sd_. 100 O = SUBMERGED OUTLET CULVERT FLOWING FULL 5 Hw•H. F b—LSo 800 120 For d ttel crow not wb1 lged,—pate H p, 6 wlsl Pods described w the ddsipn procedure Boo 108 .8 500 96 r. 1.0 400 84 i 300 -72 66 E by ! F- 200 60 IL p �y W - 2 54 / Z N 0-40 ___ •110 w 48— ��o p0 f� x 3 O 100 z ---� pp w o f a 2 o 3 lip" Lu= 4 3 6 Apo apo 5 v 60 v N W 3 3 pp oo 6 50 6 W 40 0 27 Q Spp f 8 30yo a 30 4 O 10 s 20 21 16 20 10 1 5 e 6 12 5 4 4.3.5-13 1/'90 N S METRO TREATMENT PLANT 0 O \ I S S ® J r IM � IM - - - - -1 I I I L ftF1 I .b I �OC Project Construction Boundaries DD #1 R/W J IM IM F - -1 rI _ IP I I I I I IM IM IM IM IM IM L _ _ J � _ S Y SW 16 th City of Renton - - - - -LJ ® I BOEING CUSTOMER I I I SERVICE TRAINING [CO-1I I L _ CENTER � I I I I LEGEND: L — — J Z❑NING 7 L I ®COMMERCIAL OFFICE CITY OF RENTON L _ J IM INDUSTRIAL - MEDIUM 30RPAxt%CZNT of MMIx Xc WORJC8 ® ©PUBLIC USE NEIGHBORHOOD MAP P-1 CHANNEL IMPROVEMENTS STA 670+76 TO 680+26.37 1 oAm 12/93 FLE NAM auwu UDD olp� sane L'=200' ps"DO= Gri+lO aWIF t�Cr� •� .oes BR/OGE \ MEMO GROUP rREA RIENr PLANT 4 LUFIE DAM \ A.IV'I!/a. / w.900' r.n.u• I I PUGfr. �• Y WfS7ERN. \ ` LT11t3'I�.CA[M rll..no.'I / err CU Kwr I / - 0.0 /i •.:.' :. ......:::..... Ilavr rre .....v ,3iir � ` aOKrwC7tFll sar aA r ArgrsnwvriG'r47 / worK k1y rnw rl'•oavA.ovrrrA umnwror r i ., / a I •�,rd` p /��/ :+:A►muw mrarw Au.-ry Ar Am-o •� �. .swoKvrvi• r I 0.D /7 �/ .. kENI .,�.• r morrs�r.ux.m.r Alavr Iwr �. as 8WING I • 1 i... nw y w.wpr my ur UU' (L CNGACRES) S7rR r /� �:1 • •'.r. no.wwaA .owaw \ F/©1 .........0: :::: . !s wrw ranA cY�eu,p'lpL(I ^ ACCM COOP" / O Q aerERLWD IY fin ::i:. ............. ndr or arc arKl0'Y(N7 MQICr i'Eiii'r'::7 iii:i.:i:iEi iij:•::. Y 1 O BOE/NG V.CF i N u<....a: ., / 1 /r 1 ---� -� —- ` y O VI tesnve ArrAwwc ru Po.rw Kx[ cvr, RENT �.'(� s.e a+mar OF rw r I 1^ \ rc O^ D.D. /7, \"')i3i�"T _• _ I w cros Of 1 M nw "J -I I" saww /' 1 c N L^4 11 ( I Q aA.^o¢.Ir Q bl I '' I inr CROUP.... 1 rxrsnvc avr[wr 1 I I l6Gd•DP' HEAL rH Y !»'A4 I I rovsO.uCrlav row I.0 �- •a � I "I 1 I - - vrs�WaW o M � SA.a4!A'O/r Of IAr�� I I � LGf/!K.DO.4C7R0 MNS?7iMNLY LAC Q I w IJM Slwr[r 1 I awm•tm/ now a+ e Ati Q V NK�Ir Or K1Y I I I1Q/ I C PorR Par SW IIM 5 y, Ara,or r r awme uW tow now o wrx ra- - cosnw avo I I•cvl w aw rc..ar lmr caysrn ct.ororuwr I w"+ww y PLAN Q ACWM $MANrtrra[RM .r. A[wnrrA^"WU L3GR J 38389 ` 1 O IAVWarAwwOW ..,1.1 Li m LO lfl n iD t pit xi$e t S.W. 16 7H S_T. ................ -- ----�--- — t>�s_ .. ......... � � � � `lam :::�-''•. r L � ` b —- S.R. 405 + 0 76 VIA On!t u-N GR lixg0ii pigig Am I TTip �. P/ g ERR � N GRADING PLAN °°�"`" °�•�' R P-1 CHANNEL STA. 570*76 TO 680t26 J7 Izay �• urr sor o•mv,r,•n memo CROUP 1REA7MENT PLANT Nfs ERN / ,a. ,ooannr . Icwsnwcww yy MA-0•A• — ra.�tr,uwrs 1 Yf►p4}pA , o.a.. 0'1 a a I r Mawr of 3 cm'nw s mt tyry'1pf-'If iar as icwr / Ir s row rww / / I,_ / rs 1 „�yf • Cal •r .� oawr saa.w sr uw soarr,1 O.O. (I o ' IE�Ttw •. :: ro,r �our .ear wr • I I / •/' • arww w.rraw Q � ■ B a U BQE/NC +� � � � �nw Y.war av u• (ccw cEr cAc�Es) u ,1,, r. nw oY.au ,awa ur 1 f r 9TER 4: /' 5 � ^ r44!� •:::i:::� /r r .+ r ALADW^ IV oor a rorr •�— r/ Esp>� / f. b 'rsp>!av PW or c=a wzaft wr Pwa[cr .:.......... ,k ' / ��,'/ �j, '�/ I •' \ b U vi OF BOEING. ro.rwPar N .� _i ,. i ;ram I•. !/� I \� Q casnvc Afr P 6 oarrw 1 _ I O.O. /7 _ _ 1 P OF 1 Kw , 1 � aar ir. l' I 1 I lSFd6D l[un»Awr a ro.•snwcnnv usfwNr CROUP rars,wo[wKaar 1 I V NO r j/{ (nrK'uJ 1 Au,gas ro er arYorro tcwunn+cnov+oar,wf v yll ur�ss,wrra orYrwws 1 ui `VRmrr GSCKY/a "1 lrj I AYCa'Cwlr{!�[ W —_ rxsnw so•A"o wslr Kmcf rw[ (r W I _ 1` A 1 S[ICM s/9Tr I I ro.or AwL naor nnowwan ow o I I ✓.aaal7(Y wr I —.-- Sw rllYsnarrr�.,� 1 A,wr a rr m'K,f rwr to•now Qw/ A 1 — (Pf11M'OJAWMr.1IfJI Ya r[la YAM' ------ PO(f LWS-XlkW aVVVM1 raW Y.I&Y4M PLAN ACWP jln%4WSC)tU ntM --- KI K/Mrw WL aYr a ESAP—J 38368 " 0 USAwKrA~MA ..r1.1 RFSTORAT/ON METHODS AND DETAILS •,g" �--�w,.,,,, r •r—am®-�.-' '-`"_ aa-;.s,.e`ms:�R::^�' m.:—Y..p+..=w.."«•�, 0.7 aM' „...- 0•rM. iI'll �00pOOOOOOO 0 0- _ wr 0000 .00000 0b O 0 0 0M--- aeow owmow..1. \ '. etie...... �. #71-DLIFE HABITAT PLANT/NC DETAIL 3 L'" M R_ESTOWATION SCHEDULE , p �"S'.'.v% `Qf .IYEV16S�li�1AT/Ai'TAL1iffiv $'IDfP6LRA/rAr ..: r^ is '�YSiYS.L.Y.54LYIL^CPf.00i �;i�'"..�:._'L.�.• I - •.o":+�.s.rod�eylr.w'o• e.'7 w '"" ''.'"' =. S. SdC7X1N B-B(fYP) (L QVG.a CREST ESpPLp PA :-A MP) It.I rS-19C,OF .A( MP RAP DETAILS .�� e ACCCSS CCWRAX P. - wmw, Bran / b IRAMSPCNI)1(V aNSXlV .. ..........1.:::: c neA<er cnc ana awry�murr // // � Q b Uo G CROSS SECTION O$ Q 2 c e m i PLAN LEG 7 sAA.z.s n.Aw � PLANTING DETAIL / ® �us1A SLOT DITCH DETAIL PLAN EXCELSIOR BLANKET DETAILS IYILLOIY PLANT/NG DETAIL ESGq_s A.[Af r.Y • M 38391 'r1'1 City of Renton P/B/PW Department Shoreline Substantial Development Permit 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page3 of 6 Attachment 8: Affidavit of Public Notice/Publication SHLTR.DOC AFFIDAVIT OF PUBLICATION Karen Tucker states that he/she is the Legal Clerk of the being first duly sworn on oath VALLEY DAILY NEWS 600 S. Washington Kent, WA. 98032 NOTFI�ATION =r a daily newspaper published six (6) times week. Said newspaper is a legal FOR SfiOREL'INE S118STANTIAL newspaper of general circulation and is now and has been for more than six ; DEVELOPMENT PERMIT r months prior to the date of publication referred to, printed and published in the Renton neon Su As hereby given that::The City of f Surface-Water,l1t111ty,has;filed an: English language continually as a daily newspaper in Kent, King County, Wash- !application for a substantial deveiopment ington. The Valley Daily News has been approved as a legal newspaper by order permit for the construction or development., of the Superior Court of the State of Washington for King County. , of T.t Wpongbfbbld 86WP.ftChehrf6lI The notice in the exact form attached, was published in the Valle Dail News ')� �� — SW,Grady Way to p Y Y SW 16th Street. The project is linear in, (and not in supplement form) which was regularly distributed to the subscribers shape and is adjacent to,and includes por during the below Stated period. The annexed notice, a f&tions,of,•a reach of Springbrook.Creek that.. Notice of A t i c at i�� -`flovJs•do the'north.;The projea,,is.generally' P P n f o r S h r e l i n e Sub— bounded by SW 16th Street on:the south, h;a'a SW Grady Way on the nortd',the.1-405' stant i'al Development Permit Oakesdale Avenue SW undeipass.on,the� east:,,The proposed channel will be con-; structed by removing the fill adjacent to the; 1-7-94 Qt 1-14-94 existing channel wWdfi-,blocks the existing: was published on 1-405 box culvert;'and bringithibox culvert.' Into service as originally intended by allow- The full amount of the fee charged for said foregoing publication is the sum of ingch flows to pass through it. The existing channel would be preserved to'convey 99. 70 some flows in larger storm events, provide $ needed flood storage,and create off-stream habitat for fish and wildlife use.The project will also provide for a trail link across the 1.405 corridor along the west bank of the Legal Clerk, Valley Daily News existing channel..The project Is located within Sections(s) 24 of Township 23 N. 1'�t In Range 4E,W.M.;in the City of Renton,King.: January 94 County, Washington. Said development is Subscribed and sworn before me this day of 19 _proposed to be within Springbrook•Creek, and/or Its associated wetlands. Any person desiring to express his views or to be notified of the action taken on this application should notify the City of Renton Development Services Division, Renton Notary Public or the State of Washington Municipal Building,200 Mill Avenue S.Ren- ton, Washington 98055 in writing of his residing at Auburn interest within thirty (30) days of the last King County, Washington publications of this notice.Publication dates of this notice are 1f7/94 and 1/14194. Published fn%Vafley.l*News Janu. VDN#1164 aevieed 7/92 ary 7 and 14, 1994..9809�'„ ' City of Renton PI&PW Department Shoreline Substantial Development Permit I-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page4 of 6 Attachment C: Site Plan SHLTR.DOC 1 � pAILROAD rob .v kac SPRiuLaRoo� -- �' �- 16 ` --- B — \°-- - Goi Bourse Sw �, ■ y , 1= TNH 130 Sewage I _ _ 7 -yoS —r• it .. M„16 1 I== © ,I R'0cf ' I PR0jEc1' a 4OCA1-10/J !Track Reservoir e. .l r• 2 1 •� i ■� Z o r CO 25 •30 SOURCE: USGS, 1973. RENTON, WA OUADRANGE MAP +.nrcr ecr.ro.• 0 1"=2000' 2000 a n raw rF ti ( IN FEET ) wo Sc%L c pO . PURPOSE: INCREASE FLOOD CONVEYANCE o PROJECT TITLE: I-405 BOX CULVERT IN: CITY OF RENTON c AND STORAGE. REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING— AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: VICINITY MAP COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: SSW/MDD APPLICATION BY: CITY OF RENTON o i SCALE: AS NOTED SHEET: 1 Of 16 DATE: 3-15-94 i C SW GRAD Y WA Y BOX CUL VER T error / L ECEND. PROPER T Y L IIVES / — - ROAD CL NT£-RL IIVL OAKESOALE AVE SW RETAINING WALL /-405 BOX CULVERT I-405 BRIDGE BRIDGE ABUTMENT 1 s R — AND SUPPORT PILING WETLAND - - 0 Kf -SDALE A VE SW \ RETAINING WALL APPROX/MA TE TOP \ \ OF BANK APPROX. TOP OF BANW I SINGLE FAMIL Y RESIDENCE ' SW 16TH ST APPROX. ORD/NARY \ \ BRIDGE HIGH WA TER MARK 1 1 1 (APPROX.. A VE. ; DEPTH 2-4 FTC Sw 16 1H sr DIRECTION OF FLOW _ - - —RMlNUYa`W't ' RETAINING WALL FOR SPRINGBROOK CREEK © 1t— 0 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING— AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING N DATUM: 1929 NGVD SHEET TITLE: EXISTING CONDITIONS PLAN COUNTY OF: KING STATE Of: WASHINGiON ADJACENT PROPERTY OWNERS: i. KING COUNTY DRAINAGE DIST. NO. t DRAWN BY: MDD APPLICATION BY: CITY OF RENTON 2. PUGET WESTERN. INC. SHEET: 2 OF 16 3. CITY OF RENTON o 1'=120' 120 DATE: 3-15-94 4. GROUP HEALTH COOPERTIVE 5. BOEING COMPANY i TRANSPORTATION6. WASHINGTON DEPT. OF 7. MUNICIPALITY OF METROPOLITAN SETTLE SEATTLE IN FEET ) c lD 0 m m I f \, 0 1 -1 20' 120 ' �` Y• / IN FEET WETLAND A LTCA TED WITHIN /-405 ROADS/DE F i `� _• _ —DRAINAGE DITCH DITCH, IS H 1 __ •� --- — — ASSUMED NOT T4 BF"WA 7ERS OF THE UNITED ., STATES'; PER 40 CFR J28.3(A). THEREFORE CU j� �`:• -,—--�� — <�'— FILL FOR PEDESTR/AN TRAIL CUL IiERT CROSSING — /S NOT RE - — —"GU L A IED.LEGEND: AREA OF HIGH IMPACT WITHIN EX/S77NC ORDINARY 1 HIGH WA 7ER MARK DUE f TO CUT/FILL FOR PROPOSED CHANNEL. ` E AREA OF LOW IMPACT WITHIN ORDINARY HIGH WA TER MARK DUE -- i- TO TEMPORARY DEWA TERING/ INC/DENTAL DIS7Z/RBANCE --------- NECESSARY TO ACCOMPLISH a PROPOSED CHANNEL CMSTRUCRON� PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) 0 I-405 CROSSING DATUM: 1929 NGVD COUNTY OF: KING SHEET TITLE: AREAS WITHIN ORDINARY o ADJACENT PROPERTY- OWNERS: HIGH WATER MARK IM- STATE OF: WASHINGTON SEE SHEET 2 OF 16 PACTED BY CONSTRUCTION. APPLICATION BY: CITY OF RENTON o DRAWN BY: MpD SHEET: 3 OF 16 DATE: 3-15-94 SCALE: AS NOTED s i ' W V 0 m 0 rn `L 40" CONC. WING WALL 1\ - l201 4NDENEO CHANNEL 0 1' -1 20• 120 \ _ ( IN FEET ) 50" /-405 BOX CUL INERT OUTLET CHANNEL _1 \ 90" STREAM CEM7FRUNE ff3W FLOW CHANNEL BANK IMPROVEMENT \ CENTERL/NE-HIGH FLOW CHANNEL 20' CONC. WINGWALL - - 40" CONC. WINGWALL ` i APPROX.. TRAIL - - ALIGNMENT --- _;_. 715"'{-405 BOX CUL INERT INLET CHANNEL EXIS771VG CHANNEL TO REMAIN LEGEND: \ LLLLTI NEW CUT/�ZL SLOPE ` PEDESTRIAN TRAIL e. BO' GABION WALL >_ 1D WI NED A N IRAA A Q/ .......................................: AL/QVAI9V7 IU S. `: `:'E ...'E[[d AEWRA691110 BY a)Y TRANSPO?TA77CW LVNS7QV I ' �. ,�' �• ..:: . .. ::::::::::::::::::::::::::::::::::::::::::::::. S/770Al-CHANNEL PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: N COUNTY OF: KING SHEET TITLE: PROPOSED CHANNEL AND STATE OF: WASHINGTON o ADJACENTT PROPERTY Y OWNERS: PEDESTRIAN TRAIL PLAN APPLICATION BY: CITY OF RENTON SEE SHEET 2 OF 16 0 z SHEET: 4 OF 16 DRAWN BY: MDD DATE: 3-15-94 SCALE: AS NOTED • 2 of , J Y. - :< - 0 1-=120' 120 a - - ( 1N FEET ) ._ .. _ .. Y .x '\ l 1 1 ♦` 1� 1 1- ♦1 �1,I � t 1 ............. 1 m PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON z AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING N DATUM: 1929 NGVD SHEET TITLE: PROPOSED CHANNEL CROSS COUNTY OF: KING ADJACENT PROPERTY OWNERS: SECTION REFERENCE PLAN STATE OF: WASHINGTON APPLICATION BY: CITY OF RENTON o SEE SHEET 2 OF 16 SHEET: 5 OF 16 DRAWN BY: MDD DATE: 3-15-94 SCALE: AS NOTED x W C (U m O m ? 0 1 =1 20' 120 - 1 ( IN FEET ) , _ ...� LEGEND. P VC MEMBRANE .1 i , 1 -- ........ ... . ----------- a ......... v, : o PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON b AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: PVC MEMBRANE PLAN COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 APPLICATION BY: CITY OF RENTON o i DRAWN BY: MDD SHEET: 6 OF 16 DATE: 3-15-94 SCALE: AS NOTED i \\\ - _ --- - 0 1••=120' 120 - , ( W FEET ) LEGEND.- FISH HABITAT COMPONENT BANKERS DWARF WILLOWS 1 ® WILDLIFE HABITAT PLANTING •ti, 1 NOTE. SEE SHEETS 13-15 - - - - - q FOR HAB/TA T DETAILS •� 3 O PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON i AND STORAGE, REPAIR UNDERCUT STREAM PI CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: FISH AND WILDLIFE HABITAT COUNTY OF: KING o ADJACENT PROPERTY OWNERS: MITIGATION PLAN STATE OF: WASHINGTON APPLICATION BY: CITY OF RENTON o SEE SHEET 2 OF 16 D SHEET: 7 OF 16 DRAWN 8Y: MOD DATE: 3-15-94 W SCALE: AS NOTED C w _ 1 .. .4 0 1 —1 20' 120 HE Its FEETmp ) T -- , 4. r �... 7: '- LEGEND: ; AREAS COHERED BY RIP RAP AREAS COHERED BY EXCELSIOR BLANkET 4 I (SEE C176 FOR DETAILS) I 1 1 i NOTE$: — _ 1. ALL DISTURBED AREAS, EXCEPT THE LOW FLOW ... CHANNEL AND WITHIN THE DRIP LINE OF BRIDGES, .... WILL BE COVERED WITH TOPSOIL AND SEEDED — WITH GRASS MIXTURE. 2. SEE SHEETS 4 AND 10-12 FOR CHANNEL SECTION LOCATION AND DETAILS. - I I,• o PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON o AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: STABILIZATION PLAN COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON APPLICATION BY: CITY OF RENTON SEE SHEET 2 OF 16 o SHEET: 8 OF 16 DRAWN BY: MOD DATE: 3-15-94 i SCALE: AS NOTED ? C co O 0) 31 21 APF ROX GWIXMO SURFACE - ---� --- - -_(� ,J It41 '--- ------------------- Io -i,IAX E Ev d 0(rpi fXISJING RfTA/NNG WAL( —cAmsioR BLANKET J I I J ROPY � RI'PRAP rAim-oR BLANKET iTR PW A&WBRANS I nL _s -J _�5 _Jo _.S -a -1J -Jo -IJ -M -IJ 1 -ro -J o J Io IJ }O n A m .O .J Jo w SECT/ON A ............. ______, I`APPROX CROUNO SURFAC£ 1 IJ ___________________ ' I / _ I EXCEL SFOR BLANKET EXISTING RCrA1AfNG WALL J I DO NOT LX57URB J ROCK ,wTrvAb 0- nL/ER C PIG�A4_A _J -J SBCT/ON n EA7SIINC AlANNCLE rJ CAB/QVS I �;, I APPROX Q?CUAD SLWACE IJ --------------- x EXCQS/GW BCAhKET 6mW EWSIING 90" to [XC£LSIAP BCANKEJ EX/SANG RETAN/NG WALLJ W7RO WAS7E J -S WACE NE o - -- PYL' /r fK I VV -J -J -A -/J �0 - -Jo -tl -.O -3! -m -15 �W -is _w -J }' J to IJ Af/ lJ x JJ .o o Jo JJ I I SBC970/V a LEGEND: o ® CUT/FILL M THIN AREA OF ~ ORDINARY HIGH WATER MARK (OHWM). 0 4 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE. REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK. MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: CHANNEL SECTIONS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON r SEE SHEET 2 OF 16 DRAWN BY: MOD APPLICATION BY: CITY OF RENTON 3 SCALE: 1"=20' HORIZONTAL SHEET: 11 .OF 16 1-=20' VERTICAL DATE: 3-15-94 x . . W C ]V - -----------• ------- APPROX LROC/NO SURFACE _ ,! ------------------- NCW Or� Q j EX/S RNC RETAIN/NG WALL RETAINING \ 1 WALL ROCK b' ! R/PRAP j r-'a 9 CR BLANKCT o ° T7L TER f)L J£R •. -J -X1 -Q! �O -17 -JO �.7 -�° -A -A -n -ao -IS � -,O -1 0 7 ,° ,! JO 11 A 1) �O �1 S° � PYL MLxQ9RANC SECTION p 20- ------------ __________ UGNT LOOS£R/PRAP ,7 ;I ? APPROX C.R SURFACE - - 10 MAX EZEV. B.O TYP ?k i •.\ �/S,07A� ROC EX/S71NG RETAAV/NG WALL 1 A� �I J RIPRAP ° ``••-'' fXL2ZSIOR BLAN4 o KET FY IER -s -J -m -A -Is -70 -,s 1 -I° -s Q s ro Is p n 70 1s M �J Jo SS PrV MEMBRANC SEL770,V 7n p I 1 s �I ------------- ----- Is ;I 21 APPROX CRCL/NO SURFACE ro ,o �' I1 ________ fAV/.9L L74AGi� .'lnNG REMAVING WALL 9-f� 7 ROCX RIPRAP _---------------'--.----- EXLLZSICR BLANKET p ° nL 7ER _s I -s -ems -n -w -Is j -ro �s P s Io rs rJ n Jn u �o a Jo ss PYL MEx/BRANE SECflojv a LEGEND: ® CUT/FILL WITHIN AREA OF ORDINARY HIGH WATER MARK (OH WM). 0 a h PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK. MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING h DATUM: 1929 NGVD SHEET TITLE: CHANNEL SECTIONS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE Of: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: MDD APPLICATION BY: CITY OF RENTC o z SCALE: 1"=20' HORIZONTAL SHEET: 12 OF 16 1"=20' VERTICAL DATE: 3-15-94 x -COSIWC I-MS Bqr Cm Wwr JrMANG SW OVAOr WA Bl1(0A.Cwr\ XJ / AfWPpC OJY7rA[M OVOC.0 SEOW'AQr IS 15 P-1 OVA-AU I01`7W /O !O LO/flow OVAMQ 601`71w 5 / PK&ORMAAt 5 0 - - 0 w..a........�-...axwxwmw 675.00 676 tQ7 677r00 6 00 679r00 PROFILE Lf CHANNEL �I+.c 20 tw I!A/sr 99DLiC evswi.•!-o5 scw OA KNr 20 15 -.---.-. - I5 r0 I ` 10 A"IM r 5 rI077[w --- 0 ---_NLar'1LOC aidpea R2RG+I------------ 0 -5 -5 67D�Q7 67r+00 67204,V 67J+00 674400 675f00 675+50 PROFILE L CHANNEL LEGEND: ® CUr1l7U WHIN AREA OF ORDINARY HIGH WATER MARK a h I O 2 Q4 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE. REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK. MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: PROPOSED CHANNEL COUNTY OF: KING ADJACENT PROPERTY OWNERS: PROFILE STATE OF: WASHINGTON 12 SEE SHEET 2 OF 16 DRAWN BY: MOD APPLICATION BY: CITY OF RENTON SCALE: 1"=100' HORIZONTAL SHEET: 9 OF 16 1"=25' VERTICAL DATE: 3-15-94 x • W ' C A (v A fX/SnNG WNCWAU-1 I ?I !a APW X CROUVD SURFACE-1 I I ro 41 3 I EXLSANC RETAN/NC WALL N/,57v CRAOE ° IX IFR o _S -1 21 O S 10 /S A 11 A m 10 �S b JS TO [1 A SECTION a7smc sW Lens sr eaoat'/� A ------------ p APPROX CROVAV SURFACE fJNl57I 07ADE b' 1 ° nCIFR ° I _S -S -SS -JO -!1 -0 -D -10 -11 -A -IS -10 -S. 0 1 /O 11 A 11 SD A IO U JO 1.1 A] L A SECrroN CUSM0 RErAMAC WAU nsMC WNCWALL 2 APPROX CROWO SURFACI'' 's /o y I� 3 F)y/S7/G74AOC ly O I S Icy �f S ROCK RYPRAP O O I -J -3 -SS -J0 41 -q -3J -.D -?J -A -IS -10 -J O J 10 11 A SJ SECTION LEGEND: ® CUT/FILL WITHIN AREA OF ORDINARY HIGH WATER MARK Z (OHWM). -11 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM Pi CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: N COUNTY OF: KING SHEET TITLE: CHANNEL SECTIONS STATE OF: WASHINGTON ADJACENTT PROPERTY Y OWNERS: DRAWN BY: MDD APPLICATION BY: CITY OF RENTON SEE SHEET 2 OF 16 0 i SCALE: 1'=20' HORIZONTAL SHEET: 10 OF 16 1"=20' VERTICAL DATE: 3-15-94 u i ' 4 C B A f[Ow_FCOw�A,vN£[ ra�f�9+ a[snvc 80219CRS ' (see Belo/B J S 'LVA. 9/ / , 7Avc BoQDCRs 07[ow f[ow J � � o ;i o' ,/7 y OWC RC E O RIPRAP 4(V atf AJ 0 PLAN rI D N rs PLAN RIS FISH HABITAT COMPONENT FISH HABITAT COMPONENT "A" "B„ 1 z.'&4 fz9/ J 24'A'A fz9/ R£S7AVC 80Y2DCRS REyrAv BoxofRs Cow fzow (—dW d B) �[OW fzow ROCF RiPRAP cnvner7r Boor SO" 700' [oc w7H Roor wAD MAT XAIW Or/r 7/7'GA[v Wr ROPE SECTION SECTION Mrs R rS A O h O U3 3 C PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: HABITAT DETAILS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: MOD APPLICATION BY: CITY OF RENTON o SCALE: AS NOTED SHEET: 13 OF 16 DATE: 3-15-94 W 2 W C /5 REBAR IMBEDDED 6' INTO COWO4ETE 4V Q. J 14"DIA. f7SH RESANC BOUtD'RS LOw�Ow- CHANNEL DETAIL A IV.TS 7A LROCYCRIPRAP 4V 47RU-K 4" . f7SH RESANC BOULDER PLAN ME ROOT WAD N.T.S 18 REHARNOT£.•Foster Ash restingFISH HABITA T COMPONENT rwith e reborthrough the tree a . ESANC BGY/LOER ..�.. boulder Use an epoxy system to anchor the rebor to the PLAN stone. ROOT WAD 1!'OIA. A7-W RESANC BOULDER J 14"-PIA. MH RESANC BOULDCRS IF LOW fLOw RO1OCX R/PRAP I TREE TRUNK �n o CUT ROOTS NEXT TO L7IANNEZ BOTTOM EL EVA T/ON SECTION DETAIL B ., N.TS p N.T.S 0 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE. REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING— AT: SPRINGBROOK CREEK (RM 0.5 TO BANK. MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: HABITAT DETAILS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: MDD APPLICATION BY: CITY OF RENTON SCALE: NOT TO SCALE SHEET: 14 OF 16 DATE: 3-15-94 • i c E Ab I wM o.er.M.w•«. 4000 00 O O 0 0 0—fA(t ne[svv w.-r E., ..�....,..P.h. o oo,o a a a 0 0 0 0 O®6—mrmw•ca;�w 0006 a a 0 0 0 O O—�'•^'onRra'ov°r 0®®®0 a a a a—PAOf1C Y PMo3C7dPr P.bh,ropp�N Mw�,Nw o �ouM(L�llR/ ti R7LDLIFE IMRITAT PLANTING DETAIL IQ / 00000000006 000000 ��� o0000 /c OY Y �.olom RYSL'1[ —ome (ASC MW/G f WSt AW Y.W.MrJ ti J o0000000 00o 0000000000 My l J'c PLANTING DETAIL 0MLOK PLANTING DETAIL K IS K LS PLANTING LIST SDVVIPW NAY£ cow ory NAK 92F 92F 21b SK O MW 9-2 OWAM KL� a rw<J R 73 AM3A'A>"ROW PAO.W SFRP BC l clwrxot J't a 73 1lMQNA ACpAFTY Ma clmztw mole R.a 73 cc-vs SRio-17A Afvm"VL .ow GL'MfAwlx 3 2 73 An—iS■abvAwA cfw=, [usav owigowwr q 0 1 '1 UU� 3 Q Yi PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF. RENTON AND STORAGE, REPAIR UNDERCUT STREAM Pi CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) 0 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: HABITAT DETAILS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: MDD APPLICATION BY: CITY OF RENTON o i SCALE: AS NOTED SHEET: 15 OF 16 DATE: 3-15-94 W x SEE SCOT CVTCH DETA/L CNANNEZ BOTriM/ CROSS SUCTION USE A CUMMON ROW CV-STABLES AV ADAVIVINC BL KErSCHANNEL BOrlDV ~ I LC OVADC--- 1 SrwLE , r� BUTT BLANKEI EDCc'S rolb-Z"WER SUCTION A NOT N T.S.Place 16 b/mkct m s/npes pcvprndic✓%r to the d:-ccte or flow. Pace blanket a donne/bottom party/W to the drxtion o/Aoi.. PLAN f EXLLZ9PP BLANKET re CIAFl � I SECTION SLOT DITCH DETAIL N Ts. 16 EXCELSIOR BLANKET DETAILS C N. Ts 16 o, cl b O U� 3 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE. REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING— AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: HABITAT DETAILS COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON SEE SHEET 2 OF 16 DRAWN BY: MDD APPLICATION BY: CITY OF RENTON SCALE: AS NOTED SHEET: 16 OF 16 DATE: 3-15-94 3 2 W City of Renton P/B/PW Department Shoreline Substantial Development Permit 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page5 of 6 Attachment D: SEPA Compliance SHLTR.DOC CITY OF RENTON MEMORANDUM Date: March 15, 1994 To: Ron Straka, Surface Water Utility From: Lenora BlaumanU� Subject: 1405 Culvert/P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU This memo is to inform you that the environmental review comment and appeal periods have ended for the Determination of Non-Significance - Mitigated for the above-referenced project. Since no appeals were filed, this decision is final. The date of Tuesday, April 5, 1994, at 9:00 a.m., has been set for a public hearing to review the land use permit application. The hearing, before Mr. Fred Kaufman, Renton Hearing Examiner, will be held in the Municipal Court Building, adjacent to City Hall, Renton, Washington. The applicant, in this case the City, is required to be represented at the public hearing. Scott Woodbury and you should attend. A copy of the Preliminary Report to the Hearing Examiner will be made available to you one week before the hearing. Please contact Georgia Shives, ext. 5582, or Sandi Seeger, ext. 5581, regarding picking up or receiving the staff report. If you have any questions I can answer, please call me at ext. 6181. Thanks. HEXMEMO.DOC DETERMINATION OF NON-SIGNIFICANCE-MITIGATED MITIGATION MEASURES APPLICATION NO(S): LUA-94-001,ECF,SP,SA,V,SM,CU APPLICANT: City of Renton, Surface Water Utility PROJECT NAME: 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) DESCRIPTION OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. LOCATION OF PROPOSAL: Springbrook Creek/SW Grady to SW 16th St. MITIGATION MEASURES: The Environmental Review Committee issued a Determination of Non- Significance - Mitigated with the following Mitigation Measures: 1. To address construction impacts of the proposed project on the natural and built environment, the applicant shall submit a construction mitigation plan for approval of the City and SCS. 2. To minimize the potential impact of temporarily routing Springbrook Creek to bypass the work area and implementing dewatering operations while construction is in progress within the existing stream channel, the applicant shall submit a bypass plan and dewatering plan for approval. 3. To address construction impacts of the proposed project on the natural and built environment, the time and extent of disturbance within the channel shall be kept to a minimum. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design, such as seeding, plantings, rip rap, and erosion control blankets. 4. To minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to the period between June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. 5. In order to determine if pollutants that may be in sediments to be removed during the project are below levels requiring special disposal and/or if additional sediment testing is required, the applicant shall submit a sediment monitoring report to the City and SCS for review. 6. To minimize potential impact to cultural resources that may be present in the project area, the individuals involved with construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City, and the Washington State Historic Preservation Officer to determine the course of action. Advisory Notes to Applicant: The following notes are supplemental information provided in conjunction with the environmental determination. Because these notes are provided as information only,they are not subject to the appeal process for environmental determinations. 1. In accordance with standard contract requirements, normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. The construction mitigation plan should include advance notification and other provisions as needed to minimize the impact of construction on the occupants of the existing house adjacent to and west of the project area. 2. To minimize the potential for impact to existing structures, the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. 3. The mitigation measures included in this determination were proposed by the applicant in the project application documents. It is the responsibility of the applicant to ensure that all mitigation is implemt rated as proposed, and that any additional information requiring review is submitted and approved prior to constrL -tion. mitmeas - 1 - 02/03/94 City of Renton P/BIPW Department Shoreline Substantial Development Permit 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001, SA, ECF, SP, V, SM, CU MAY 4, 1994 Page6 of 6 Attachment E: Copy of Final Order SHLTR.DOC % - ' CITY OF RENTON "LL Hearing Examiner Earl Clymer, Mayor Fred J. Kaufman May 5, 1994 Ms. Lenora Blauman Project Manager City of Renton 200 Mill Avenue South Renton WA 98055 Re: I-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT (SPRINGBROOK CREEK), FILE NO. 94-001, SA/ECF/SPN/SM/CU Dear Ms. Blauman: The Examiner's decision was published on Tuesday, April 19, 1994. The decision was not appealed within the 14-day period established by ordinance. Therefore, this matter is considered final and is being transmitted to the City Clerk as of this date for filing. Please feel free to contact this office if further assistance or information is required. Sincerely, Fred J. Kaufman Hearing Examiner FJK/dlf cc: City Clerk Building Division Development Services Division Leslie Betlach Jim Douma Bill Hutsinpiller John Neller Lori Pitzer Scott Woodbury I405.doc 200 Mill Avenue South - Renton, Washington 98055 - (206)235-2593 �`0 ) CITY OF RENTON "LL Hearing Examiner Earl Clymer, Mayor Fred I Kaufman May 5, 1994 Ms. Lenora Blauman Project Manager City of Renton 200 Mill Avenue South Renton WA 98055 Re: I-405 Box CULVERT/P-I CHANNEL IMPROVEMENT (SPRINGBROOK CREEK), FILE No. 94-001, SA/ECF/SPN/SM/CU Dear Ms. Blauman: The Examiner's decision was published on Tuesday, April 19, 1994. The decision was not appealed within the 14-day period established by ordinance. Therefore, this matter is considered final and is being transmitted to the City Clerk as of this date for filing. Please feel free to contact this office if further assistance or information is required. Sincerely, Fred J. Kaufman Hearing Examiner FJK/dlf cc: City Clerk Building Division Development Services Division Leslie Betlach Jim Douma Bill Hutsinpiller John Neller Lori Pitzer Scott Woodbury 1405.doc 200 Mill Avenue South - Renton, Washington 98055 - (206)235-2593 k� April 19, 1994 OFFICE OF THE HEARING EXAMINER CITY OF RENTON CITY OF RENTON PPCRIVED REPORT AND DECISION APR z 0 1994 APPLICANT: City of Renton 0UJLui1VU LIVISOON Planning/Building/Public Works Surface Water Utilities Section I-405 Box Culvert/P-I Channel Improvement (Springbrook Creek) File No.: LUA-94-001, SA/ECF/SP/V/SM/CU LOCATION: Springbrook Creek/SW Grady Way to SW 16th Street SUMMARY OF REQUEST: To complete construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. SUMMARY OF ACTION: Development Services Recommendation: Approve with conditions. DEVELOPMENT SERVICES REPORT: The Development Services Report was received by the Examiner on March 31, 1994. PUBLIC HEARING: After reviewing the Development Services Report, examining available information on file with the application, and field checking the property and surrounding area, the Examiner conducted a public hearing on the subject as follows: MINUTES The following is a summary of the hearing held April 5, 1994. The following is not verbatim transcript. The official record is recorded on tape. The hearing opened Tuesday, April 5, 1994, at 9:03 a.m., in the courtroom of the Municipal Court. Parties wishing to testify were affirmed by the Examiner. The following exhibits were entered into the record: Exhibit No. 1: Yellow File containing application, proof of posting, publication and other documentation pertinent to this request. Exhibit No. 2: Site Plan. Exhibit No. 3: Rehabilitation Landscape Plan. Exhibit No. 4: Grading plan. Exhibit No. 5: Site plan for the Oaksdale Underpass Trail Alignment. City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 2 Substituting for the project manager, Lenora Blauman, SCOTT WOODBURY, City of Renton Public Works, 200 Mill Avenue S, Renton WA 98055, presented the project staff report. Mr. Woodbury stated that the project will complete the construction of the P-1 Channel improvements, from SW Grady Way to SW 16th Street. It is the final segment of a series of flood control improvements to the Springbrook/P-I Channel, made from 1984 to 1990, with the assistance of the US Department of Agriculture Soil Conservation Service. Presently, the Springbrook Creek stream channel directs drainage flow, from a 22 square mile watershed, north under the SW 16th bridge toward the I-405 box culvert. This project is proposed for funding and construction in the 1995 transportation improvement program. The functioning of the channel will be improved by this project and it will provide benefits such as improved flood conveyance and storage, fish and wildlife habitat enhancement, water quality improvement, alleviation of erosion control problems, and public access. The Black River Pump Station forebay and the Black River Riparian Forest are north of the site. Industrial, office, and commercial uses are to the east. The Boeing Customer Service Training Center(CSTC)and Renton-Kent Green River Valley industrial and commercial lands lie to the south. To the west is the Metro Sewage Treatment Plant. There is limited access to the site from SW 16th Street and Grady Way. The project area is 3 1/4 acres. The box culvert is presently blocked by fill, which forces water flow west around the box culvert and underneath the adjacent I-405 bridge. Construction of a new inlet channel will direct water flow into the box culvert. The existing channel will also be widened to a point just south of the SW 16th bridge. This will involve constructing an outlet channel to the I-405 box culvert and widening the channel between I-405 and SW Grady Way culvert. The associated excavation will provide approximately 4 acre feet of flood water storage thereby reducing the risk of upstream flooding. The project was identified as needed by a 1978 watershed plan and this need was confirmed in a recent analysis by the Cities of Renton and Tukwila. Existing flood conveyance control structures are located at the site and viable alternative uses are limited by site characteristics (flood levels, steep slopes, riparian habitat, and limited access and development restrictions under the shoreline master program and zoning ordinance.) Construction of the project will require that Springbrook Creek be temporarily rerouted in order to bypass the project area during construction. Rerouting Springbrook will temporarily prevent passage of fish through the channel. During the construction process, the entire channel area will be cleared of existing vegetative cover. Birds and wildlife, on or near the site, may be temporarily displaced by the project. To address these impacts, the extent and time of the construction disturbance within the channel will be kept to a minimum. The project design includes a plan for stabilization of the site during, and immediately following, construction. After construction, permanent plantings, trees, and ground cover seeding will be introduced to reestablish the removed vegetative cover. Fish habitat enhancement components include placement of root wads and boulder groups in the low flow channel that will create resting areas for migrating fish. The pedestrian trail component of the project includes two alignments. The trail link would provide pedestrian and bicycle access through an area where there is no current access and would connect to existing and proposed trails. The trail alignment consists of a 14 foot wide pedestrian path (12' paved with P gravel shoulders) from SW Grady Way to approximately 80' short of SW 16th Street. The remainder of the pedestrian trail falls within a corridor. How the trail will be completed within this corridor includes several options for crossing SW 16th Street. One option is a pedestrian trail crossing opposite the new Boeing Customer Service Training Center (CSTC)driveway. The second option is directly opposite the CSTC pedestrian trail. The original west bank alignment proposal was not completed because of the potential high cost of acquiring the property rights in order City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SPN/SM/CU April 19, 1994 Page 3 to establish a pedestrian trail link. Also, the connection to SW l6th Street could not be made until concerns with the crossing location were resolved through further study. Eventually, it was decided to consider other trail alignments for crossing the corridor. Two trail alignments are proposed. The alignment to be constructed first is the underpass alignment along Oaksdale Avenue. The City is negotiating for the necessary property rights on the west bank option. The City requests that both alignments be permitted. If the project is permitted,the City will be able to proceed directly into construction. Mr. Woodbury noted that if an agreement is not reached regarding the terms of the west bank acquisition, then the west bank project may be abandoned. The applicant seeks a variance to remove vegetation since construction activity improvements will take place within 25 feet of the Springbrook Creek high water mark. Also, more than 500 cubic yards of soil will be removed. The proposed construction is classified as a medium utility, which requires an administrative conditional use. The project is consistent with the Comprehensive Plan. The project is permitted as a conditional use in the Medium Industrial (IM)and Commercial Office(CO)Zones. The IM zone requires portions of the site, not covered with structures or their appurtenances, to be maintained as permeable areas and improved with native, drought resistant vegetative cover. Referring to the widening of the channel, the Examiner asked about water flows and asked if widening the channel would dewater the south aspects of the creek. Mr. Woodbury stated that this was reviewed by the Soil Conservation Service and explained that this proposed project includes a larger, wider flood conveyance channel and a low flow channel. Presently, the box culverts at I-405 and Grady Way both have a low flow cell to which the proposed channel will connect. Dewatering issues were investigated using watershed models to determine whether, at times of low flow, upstream areas would be affected. It was determined that there would be no impact. The reduction in flooding levels would be primarily during high flow periods. The proposed channel is not much lower than the existing channel so existing ground water levels will not be significantly affected by the project. During construction, the entire area will be dewatered for a short period of time. Due to the difficulty of anticipating site conditions, the dewatering and bypass plans will be determined later. At that time, the contractor will be required to submit its dewatering and bypass plans to the City. To minimize impacts, construction will take place during the low flow period of the summer months; and in accordance with permit conditions that will be established by the Washington State Department of Fish and Wildlife. Usually, the fisheries'window is between June 15 to September 15. However, if the City is required to obtain a Section 404 Individual Permit from the Corp. of Engineers, they may not be able to start construction until some time into the summer construction window. On the possibility of a delay in the construction start time, the City is coordinating with the Department of Fisheries for a possible extension into October of the construction window. A site plan approval is sought for the pedestrian trail component of this project. The pedestrian trail area will be cleared before construction and will be restored, as nearly as practicable, to the same condition found before construction. The soil erosion potential, due to clearing of the vegetation, will be minimized through implementation of an erosion control plan and a construction mitigation plan. The contractor will be required to submit its erosion control and construction mitigation plans to the City. The proposed pedestrian trail will not present any visual obstructions to adjacent areas. The trail location and landscaping improvements are designed = to be consistent with other segments of the Springbrook Trail system. Access to the trails will be from the surrounding developments, and will be facilitated by linkages to existing trail segments. The orientation of the trail will allow trail users, and users of nearby properties, to enjoy the natural characteristics of the site., The open construction of the trail will allow users to enjoy sunlight, air, and prevailing winds. There will be no interference with light or air circulation to the neighboring properties. The excavation required for the pedestrian trail alignments will be kept to the minimum necessary to install the facilities. The trail surfaces will be paved City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SPN/SM/CU April 19, 1994 Page 4 with asphalt. Trail street connections will be paved with concrete to ensure a safe and level corridor for pedestrians. The proposed west bank alignment is to be a maximum 12 feet paved in width, with 1 foot gravel shoulders. The alternate proposed underpass alignment is would be 7 feet in width. Private vehicles will not be permitted to use the trail. The only vehicles allowed will be City maintenance and emergency vehicles. The proposed trail is considered by staff to be a public improvement and will serve to improve or increase area wide property values. During construction of the channel, erosion control measures (such as silt fences, straw mulch for temporary protection of exposed soils, stabilized construction entrances and wash pads)will be utilized. A special permit is required by the Mining, Excavation and Grading Ordinance to allow excavation and grade/fill activities to prepare the site. Approximately 15,000 cubic yards of soils are to be removed, of which 2,100 cubic yards would be removed from within the area of the ordinary high water mark of Springbrook Creek. Approximately 8,100 cubic yards of new fill would be introduced, of which 1,700 cubic yards would be introduced into the area within the ordinary high water mark of Springbrook Creek. The fill is proposed in order to establish desired grades and a suitable base. Necessary truck trips are estimated at 1,000. The contractor will be required to submit a construction mitigation plan. Sediment testing has been conducted on the site and there is no evidence suggesting that any type of special disposal will be required of the excavated soils. Mr. Woodbury stated that staff recommends approval of the Conditional Use Permit for construction of the improvements to the P-1/Springbrook Creek Channel; a Site Plan Approval for the Springbrook Creek pedestrian trail; a Variance from the Land Clearing and Tree Cutting Ordinance; and a Special Permit for site preparation, with the conditions as outlined in the staffs report. The Examiner asked for comment from Community Services, Parks Department of the various proposed alignments. LESLIE BETLACH, Resource Coordinator, Community Services, City of Renton 200 Mill Avenue S, Renton WA 98055, stated that the proposed underpass alignment is consistent with the adopted Comprehensive Parks and Trails Plan. Eventually, it will tie into the proposed trail alignment when Oakesdale Avenue is extended from SW 16th, southward. The underpass alignment will be primarily a transportation type alignment for bicyclists. Parks is pursing negotiations with Puget Western for the westbank alignment. The Parks Department envisions a more pedestrian oriented corridor system that will tie into the Boeing system. Eventually, they would like to see a pedestrian trail system along the P-1 Channel, and more of a transportation bicycle system along Oakesdale Avenue. Until negotiations are completed with Puget Western,the underpass alignment is a good alternative. Parks has acknowledged that the alignment under Oakesdale will probably be a dismount zone since it is 7 feet in width. The dismount zone is not an optimum option but it is the best that can be accomplished at this time. The Examiner called for further testimony regarding this project. There was no one else wishing to speak, and there were no further comments from staff. The hearing closed at 10:00 a.m. FINDINGS. CONCLUSIONS & DECISION Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. The applicant, City of Renton Department of Planning, Building and Public Works, filed a request for approval of a series of permits to realign Springbrook Creek, complete a series of flood control J City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 5 improvements in the vicinity of Springbrook Creek(between SW Grady Way and SW l6th Street)and the passage under I-405. 2. The applicant has applied for a Conditional Use Permit to install a "medium utility," a storm water channel in the Medium Industrial and Commercial Office Zone. Review was delegated to the Hearing Examiner by the Site Plan Review Committee so that all public hearings and review would be coordinated. The applicant also applied for a Special Permit to Fill and Grade portions of the site since both excavation and importation of fill materials are required. A Variance is necessary, per the Land Clearing and Tree Cutting Ordinance, since vegetation will be removed from the new alignment. Finally, Site Plan review is required for the development of a pedestrian trail. 3. The yellow file containing the staff report, the State Environmental Policy Act(SEPA) documentation and other pertinent materials was entered into the record as Exhibit No. 1. 4. The City relied upon the Environmental Impact Statement(prepared under Federal auspices)as well as amendments and supplements and additional studies it conducted, in a complex series of reviews and adoptions. 5. The subject proposal was reviewed by all departments with an interest in the matter. 6. The subject site is located just west of Oakesdale Avenue SW and between SW 16th Street and SW Grady Way. The site is located near the western margin of the City; south of the Metro Treatment Plant and includes the area where I-405 passes over Springbrook Creek. 7. The proposal will improve the existing channel and open an approximately 500 foot channel slightly to the east of the current Springbrook alignment. The new segment would channel the creek into a box culvert located under 1-405. The box culvert was constructed in accordance with Conditional Use Permit CU-088-88 issued in May, 1988. The City will stabilize the old banks, import fill materials. It will also construct a pedestrian, and possibly a bicycle path, along the west bank of the old creek alignment that will provide passage under I-405. 8. Channel improvements will provide an additional 4 (four) acre-feet of floodwater storage. This would be accomplished by additional excavation and creation of side by side, parallel channels. During storm events, additional water would be conveyed in the additional channel. 9. This system is part of the original planned complex that drains an approximately 22 square mile area. The system terminates about a mile upstream, at the Black River Pump Station. This pump station pumps water from this system into the Duwamish River system. The system also includes the forebay to the pump station that was excavated in order to provide additional storm water storage capacity. Plan changes, for areas south of the subject proposal, continue to be studied. Staff reports that the completion of the subject proposal will not dictate any particular outcome for components south of the subject site. While this may be true, the same arguments that are made in support of this portion of the channel will probably be used to justify further widening-- as this project will move the constriction in the "pipe" further downstream. 10. In order to perform the proposed work, including bank stabilization, opening the new channel,- landscaping and trail construction, the applicant will have to divert the existing creek and water flow. Obviously, this will interrupt wildlife and fish patterns as well as habitat. Staff indicates that disruptions will be kept to a minimum and the work will be accomplished in approximately 55 days. 1 City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 6 11. The Fisheries Department has reviewed the project and has specified a construction window to minimize interference with migrating salmon species and other anadromous fish. This limitation is applicable to the old channel and would run from June 15 to September 15. The Department of Fish and Wildlife might extend the window, depending on circumstances. The construction start date may be affected by achieving the necessary permits from the Army Corps of'Engineers, weather, and unforeseen site constraints. 12. The applicant proposes a trail to be located along the west bank of the existing creek. This trail would provide passage underneath I-405. Originally, a trail was supposed to be provided along one of the box culvert channels, in lieu of the sidewalk along Oakesdale Avenue SW. The current arrangement prevents pedestrians from walking from the Valley, south of I-405, to the north side of 1-405 --without a long detour to Lind Avenue SW. 13. Trail alignment is designed to be approximately 80 feet from SW 16th Street. The City is not certain where the trail will cross SW 16th and has therefore left that link undefined. It could match (as closely as possible) a driveway on the south side of 16th Street; or, match a trail being constructed by The Boeing Company. 14. There are concerns about acquisition of property for the proposed trail. The City has devised an alternate route that would actually share the roadway under the Oakesdale underpass. The City may provide both routes. 15. Construction will take place in and along the existing stream corridor as well as in the new alignment just east of the existing creek. The removal of vegetation within 25 feet of the ordinary high water mark of a crce!c is prohibited by the Land Clearing and Tree Cutting Ordinance(Section 4-9-5(D)). Therefore, the applicant has applied for a variance to allow the removal of vegetation in this area. 16. The subject site is zoned Medium Industrial (IM) in the area between I-405 and SW 16th Street (approximately 1.2 acres). The areas north of I-405 and south of SW 16th Street is zoned Commercial Office (CO). Both areas total 2.0 acres. 17. Many bicyclists employ a cleat engaging pedal and corresponding cleated shoe. The cleat is located at the ball of the shoe and engages the pedal. The cleated shoe makes walking very difficult and dangerous, thereby rendering dismount and walk zones an impediment to safe and efficient cycling. Finally, the creation of a two-way bicycle path on one side of an active roadway is an accident waiting to happen -- particularly a path that accommodates bicyclists and pedestrians. 18. The applicant will excavate approximately 15,700 cubic yards of soils from the site, including approximately 2,100 cubic yards from an area within the ordinary high water mark. The applicant will import approximately 8,100 cubic yards of materials for use in various areas of the 3.25 acre project site. Approximately 1,700 cubic yards will be placed below the ordinary high water mark and approximately 500 cubic yards to support the trail. 19. As noted above, limitations imposed by the Fisheries Department will limit the construction operations to approximately 55 days. The amount of materials that will be moved in this time period will require approximately 1,000 truck trips. Since this is a City sponsored project the applicant will be coordinating the routes in order to minimize interference with rush hour traffic. In addition, the proximity to the I-405 roadway realignment will require coordination with the state. 20. The applicant will be providing erosion controls to all of its fill and grade operations in order to avoid siltation of the creek and channels. Measures will include rip rap, blankets, hydroseeding, and landscape i City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SPN/SM/CU April 19, 1994 Page 7 restoration as the project progresses. The applicant will adjust its operations to be consistent with weather conditions to avoid storm exacerbated erosion. 21. The creek may be dewatered to provide a reasonably dry working environment. These plans have been coordinated with Metro, which might receive the displaced water. Plans have also been coordinated with the Fisheries Department regarding fish passage and preservation. The applicant proposes working in two phases in order to reduce the overall distance that the stream bed will need be dewatered. 22. The applicant will monitor dredge spoils for contaminants. Previous sampling has shown levels to be within the range that will permit the normal disposal of the spoils. The applicant will monitor materials as they are removed from the site and materials will be appropriately disposed of depending upon their properties. CONCLUSIONS: Conditional Use Permit 1. The applicant for a Conditional Use Permit must demonstrate that the use is in the public interest, will not impair the health, safety or welfare of the general public and is in compliance with the criteria found in Section 4-31-36 (C)which provides in part that: a. The proposal generally conforms with the Comprehensive Plan; b. There is a general community need for the proposed use at the proposed location; C. There will be no undue impacts on adjacent property; d. The proposed use is compatible in scale with the adjacent residential uses, if any; e. Parking, unless otherwise permitted, will not occur in the required yards; f. Traffic and pedestrian circulation will be safe and adequate for the proposed project; g. Noise, light and glare will not cause an adverse affect on neighboring property; h. Landscaping shall be sufficient to buffer the use from rights-of-way and neighboring property where appropriate; and i. Adequate public services are available to serve the proposal. The requested conditional use appears justified and will be approved. 2. The Comprehensive Plan has a wide variety of policies and goals that touch on this project. The plan even has somewhat contrary goals and policies, where it calls for preservation of natural resources while also calling for flood control. The subject proposal attempts to balance conflicting goals by incorporating bank stabilization and erosion control measures as well as replanting native landscaping materials; while opening the new box culvert channel that will expedite the movement of flood waters out of tlhe area and therefore protect life and property from potentially dangerous storm water events. 3. In addition, the project and the necessary construction have been designed to minimize disruption to the natural systems of the stream and corridor. It is clearly impossible to open a new channel, and stablize the existing channel, without disrupting some aspects of the ecosystem. With that in mind, the project City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 8 will be timed to avoid interferring with fish migration. Landscaping will be installed as quickly as possible. The site will be returned to useable habitat as quickly as possible. Springbrook Creek has been altered substantially over the years and vegetation removal and natural loss has opened the stream to the warming effects of the sun. The applicant will be adding vegetation to counter such problems. Stream temperatures will be stabilized by the introduction of shade trees along the banks of the creek. 4. The proposed project will also alter the legal status of the stream complex from legally non-conforming to conforming with the approval of this proposed Conditional Use Permit. The proposal is considered a medium utility improvement and with a conditional use permit may be allowed in both the IM and CO zones. The proposal is also consistent with the Flood Hazards and Landscaping section of the Zoning Code. Bank stabilization and revegetation are recommended to reduce flood hazards and erosion that diminish the storage capacity of receiving bodies. 5. The proposal has been an element of regional flood control for many years. This demonstrates a community need for such a proposal. Even with changes in analysis, this proposal is necessary to accommodate the existing flood control structures. In addition, the proposal will accommodate a section of trail that is an important link in the City's trail system. This project will attempt to link the Valley with the north side of 1-405 by one of two trail proposals. 6. The nature of the proposed use severely limits its location and what can be constructed. Realistically, the proposal can only be constructed in this location. The box culvert is already in place and the stream and bridges constrain any flexibility in corridor improvements. 7. The proposal should not have any adverse impact on adjacent properties. Most of the project will be built at or below grade and this will limit any impact on view or the passage of light and air to surrounding properties. The proposal should result in less potential flood damage to surrounding properties. The introduction of the trail might bring more pedestrians to the area but given the nature of the location, the intersection of Oakesdale and SW 16th, I-405 and Grady, the additional pedestrian passage should hardly be noticed. 8. Again, the nature of the project is such that it will be mostly accommodated below grade thereby keeping the scale of the proposal in line with any surrounding development. 9. The City is working on plans to assure that all pedestrian and bicycle traffic will be channelled appropriately along the corridor, or under Oakesdale Avenue. The City will be required to consult with local bicycle advocacy groups to assure that proposed routes and designs will work for both recreational bicycle riders and bicycle commuters. An appropriate design under the Oakesdale underpass will need to accommodate the needs of cyclists. If this is not done the system will not be used by cyclists, resulting in cyclists utilizing the narrow road. This would thwart the City's efforts to accommodate vehicles and bicyclists. The expectation that commuting bicyclists should be required to dismount while commuting is unreasonable. Bicycle commuting is a reasonable method of commuting and has the right to be afforded full respect and roadway privileges. A practical approach may be to fully sign the underpass approach, and underpass, alerting drivers to be aware that bicyclists use the underpass and to exercise caution. 10. There should be no adverse light or glare impacts as a result of the proposal. After construction there should not be any appreciable noise generated by an aspect of the proposal. 11. With the exception of the introduction of dwarf willows to shade the stream bank, planting will be drought resistant native plants. The willow has proven to be a beneficial shade tree along the lower reaches of the creek to enhance temperature control. Y City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 9 Site Plan Approval 12. The criteria for site plan review more or less parallels those for a conditional use permit. The public trail is the aspect of this proposal that is subject to Site Plan review. As noted above, normally Site Plan review of a project of this nature would be administrative. Staff has determined that since two components of the proposal were subject to public hearing(the Special Permit for the excavation, fill and grade; and a variance from the Tree Cutting Ordinance within the stream corridor)that Site Plan review should also be reviewed at public hearing. 13. As indicated above the general proposal appears to comply with the Comprehensive Plan. The same can be said for the specific trail component. The City's Trails Master Plan calls for a pedestrian and bicycle link from the areas of the City north of the Valley, north of I-405 to the Valley and trails already developed and being developed along Springbrook Creek south of I-405. In addition, these links will connect to regional trails south of the City. 14. The proposed trail meets the public access goals of the City's Shoreline Master Program (to be reviewed separately). 15. While the City has not completed acquisition of the entire proposed alignment, if it does, it will not adversely affect area-wide property values, nor should it result in neighborhood deterioration or blight. While sections of this link will be under various roadways, including I-405, there should still be adequate air and light. 16. As with the Conditional Use Permit, there should be negligible impacts on surrounding properties and uses. There should not be any adverse effects on property values from the development of the trail. 17. There should not be any adverse impacts on the site itself from development of the trail. While the trail will be paved, it will meander through a landscaped area immediately adjacent to the channel. 18. Issues of pedestrian safety were addressed in the above discussion as was the issue of bicycle traffic. If the two modes of travel can be provided separate corridors, both segments of the public would be better served. The trail should be able to accommodate both populations if that becomes necessary. Again, the City will be required to coordinate its efforts with a bicycle advocacy group to assure that it makes appropriate decisions concerning accommodating bicycles on either route. 19. In summary, the proposed Site Plan appears appropriate for the proposed purpose and for this particular location. Special Permit for Fill and Grade 20. The proposed excavation, fill, and grade appears to serve public use and necessity. The proposed action will require excavation and importation of materials. The applicant will excavate approximately 15,700 cubic yards of soils from the site, including approximately 2,100 cubic yards from an area within the ordinary high water mark. The applicant will import approximately 8,100 cubic yards of materials for use in various areas of the 3.25 acre project site. Approximately 1,700 cubic yards will be placed below the ordinary high water mark and approximately 500 cubic yards to support the trail. 21. The combined excavation and importation is intended to stabilize the channel, realign and open the second channel of the creek, fill an exempt wetland, and provide a suitable foundation for the proposed trail and landscape materials. r City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 10 22. The applicant will be limited to an approximately 55 day window imposed by the Department of Fisheries. This 55 day window also limits the operation's impact on habitat, traffic, noise, dust, and other aspects of earth moving. 23. The project will be providing erosion controls to avoid siltation of the creek and channels. As indicated, landscaping will be provided as part of the overall project and not particularly in regard to the grading and filling operation. Variance 24. Variances may be granted when the property generally satisfies all the conditions described in part below: a. The applicant suffers undue hardship caused by special circumstances such as: the size, shape, topography, or location where code enforcement would deprive the owner of rights and privileges enjoyed by others similarly situated; b. The granting of the variance would not materially harm either the public welfare or other property in the vicinity; C. The approval will not constitute a special privilege inconsistent with the limitations on other property in the vicinity; and d. The variance is the minimum variance necessary to allow reasonable development of the subject site. The applicant's property appears ripe for the variance requested. 25. It is quite clear that the subject site is unique as is the work proposed. The site is actually a stream corridor and its associated uplands. There is obviously no way to connect portions of the original channel to the new box culvert's channel and to stabilize the existing channel without working within 25 feet of the stream corridor. Any work within this corridor will necessitate disturbing vegetation. Therefore, the topographical constraints and location of the project require a variance to permit the work. 26. While the work will result in the removal of vegetation and temporary loss of habitat, the project is intended to safeguard the stream corridor by stabilizing the creek banks, prevent erosion, and sluffing. The applicant's plans call for the reintroduction of mostly native vegetation as soon as practical to restore the habitat and to achieve a stable environment. Also the work will reduce flooding resulting in a net gain for the general public welfare. 27. The site is unique and therefore it is unlikely to result in the grant of a special privilege or set an undue precedent. 28. The variance appears to be the minimum necessary to permit the proposed rechannelization and bank stabilization. 29. In conclusion, the work will result in at least a temporary change to the existing conditions regarding water quality, water quantity, habitat, and vegetation. This has been anticipated. The ultimate result though should be improved flood protection, enhanced stream corridor environment and an area for public assess to the shoreline. The array of permits required appear justified and should be approved. v City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SP/V/SM/CU April 19, 1994 Page 11 DECISION: The Conditional Use Permit, Site Plan, Special Permit for Fill and Grade, and Variance are approved subject to the following conditions: 1. The applicant shall comply with the conditions imposed by the ERC. 2. The applicant shall submit and be bound by a Construction Mitigation Plan that shall be approved by the Department of Fisheries and Wildlife of the State of Washington. 3. Any modifications of the Plan shall be subject to review and approval of both City and appropriate State agencies and divisions. 4. The Pedestrian and Bicycle trails shall be completed no later than 1 year after the channel improvements have been completed. 5. The City shall actively consult with local Puget Sound Bicycle Advocacy groups for any "bicycle" path and or passage either on the "West Bank" trail or in the Oakesdale alignment. The City shall avoid creating any hazardous dismount zone when creating the bicycle component of the trail link. The City shall put caution signs on approach roads to the Oakesdale underpass which warn drivers that bicyclists may be using the underpass roadway. ORDERED THIS 19th day of April, 1994. FRED J. KAUF HEARING EXANYqER TRANSMITTED THIS 19th day of April, 1994 to the parties of record: Scott Woodbury City of Renton 200 Mill Avenue South Renton WA 98055 Lenora Blauman City of Renton 200 Mill Avenue South Renton WA 98055 Leslie Betlach Community Services, City of Renton 200 Mill Avenue South Renton WA 98055 v City of Renton, Planning/Building/Public Works Surface Water Utilities Section File: LUA-94-001, SA/ECF/SPN/SM/CU April 19, 1994 Page 12 Bill Hutsinpiller Community Services, City of Renton 200 Mill Avenue South Renton WA 98055 Jim Douma Group Health Cooperative 521 Wall Street Seattle WA 98121 Lori Pitzer Boeing Commercial Airplane Group P.O. Box 3707, MS 6W-90 Seattle WA 98124-2207 John Neller 1300 S. Eagleridge, #1069 Renton WA 98055 TRANSMITTED THIS 19th day of April, 1994 to the following: Mayor Earl Clymer Councilman Richard M. Stredicke Members, Renton Planning Commission Gregg Zimmerman, PlanBldg/PW Administrator Art Larson, Fire Marshal Jim Hanson, Development Services Manager Lawrence J. Warren, City Attorney Mike Katterman, Interim Technical Services Manager Transportation Systems Division James Chandler, Building Official Utilities System Division Jay Covington, Mayor's Executive Assistant Valley Daily News Pursuant to Title IV, Chapter 8, Section 15 of the City's Code, request for reconsideration must be filed in writing on or before 5:00 p.m., May 3, 1994. Any aggrieved person feeling that the decision of the Examiner is ambiguous or based on erroneous procedure, errors of law or fact, error in judgment, or the discovery of new evidence which could not be reasonably available at the prior hearing may make a written request for a review by the Examiner within fourteen (14)days from the date of the Examiner's decision . This request shall set forth the specific ambiguities or errors discovered by such appellant, and the Examiner may, after review of the record, take further action as he deems proper. An appeal to the City Council is governed by Title IV, Chapter 8, Section 16, which requires that such appeal be filed with the City Clerk, accompanying a filing fee of$75.00 and meeting other specified requirements. Copies of this ordinance are available for inspection or purchase in the Finance Department, first floor of City Hall. If the Examiner's Recommendation or Decision contains the requirement for Restrictive Covenants,the executed Covenants will be required prior to approval by City Council or final processing of the file. You may contact this office for information on formatting covenants. ti City of Renton, Planning/Building/Public Works Surface Water Utilities Section • File: LUA-94-001, SA/ECF/SPN/SM/CU April 19, 1994 Page 13 The Appearance of Fairness Doctrine provides that no ex parte (private one-on-one)communications may occur concerning pending land use decisions. This means that parties to a land use decision may not communicate in private with any decision-maker concerning the proposal. Decision-makers in the land use process include both the Hearing Examiner and members of the City Council. All communications concerning the proposal must be made in public. This public communication permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence. Any violation of this doctrine would result in the invalidation of the request by the Court. The Doctrine applies not only to the initial public hearing but to all Requests for Reconsideration as well as Appeals to the City Council. r P-1 _ METRO TREATMENT PLANT rJ IM L � 1 I � I i i Project Construction Boundaries 405 DD #1 R/W IM IM _ IM I I I I r ---II I I I I M IM IM IM I I L I I I I IM I I LJ LJ I — - - J 'sL- - -� Y i SW 16th City of Renton — ZJ 0 BOEING CUSTOMER I I I SERVICE TRAINING ® I I L — CENTER — — — — -J I i I I I I ® I I i I L - - � LEGEND: ZONING ®COMMERCIAL OFFICE CITY OF RENTON L — J M71NDUSTRIAL - MEDIUM DEPARTUMNT or rvsL.1c woxxs l� P-1 PUBLIC USE NEIGHBORHOOD MAP P-1 CHANNEL IMPROVEMENTS STA 670+76 TO 680+26.37 DES O M DAT16 12/09 Ili HAMS O RDKD toA►1 l'=200' iae m� Mo Kyyp� tY AMR DATt AMQOVI& �T' r T•T-- L i r w.,G-W-cxA,sa, Jvrid INn tlw.bY.MNOY i1YSn7 - I ' �•m• o ..w,o =v 1 „r.r.IN as I 1 I f�Iw A.MYM✓r ,vr"—a,.sw a.,..a ar.s" n Man �q K d17OW .OriYrW.oU Jo ✓ 00 / Aw ,�. 3 - 9 q I .'... c. '' Ip * ; 1 , .,✓ �05 a,rrwa r 1 i "p I s.mrzai►r V .' 1yi sue, M •. bps ,/� M Y...�..�'.'Olrw..Y . ,• � O I :a• ✓ �►l ' �. AM ..ew l .w fr..ov M'i1N rya.r...w raow XI a..rN wrw.m itrr wuo.r.s� /' � - � � .�'� I '� ' ' / ..o�sr�.nuw,w.L,n w✓w IrJ.N Ip/ . i n unw 00 kl ..�urrus.Vv u / iaom ` % NC(3(S3M Arm,-r /19/kl I .9v iv \ / w.i....-o vivo-MU3 ,NV 7d l NIM✓J&I ` oy bo OAU7M \ -M(�Ok1H l`'�— su.r .ourw.sKu CITY OF RENTON HEARING EXAMINER PUBLIC HEARING AP RI L 5 1994 ::>::: ::.....:>.....:; AGENDA :.;:.::.::.....:......:....;:.;:... COMMENCING AT 9:00 AM :;:. :;:>::::>::::>::>::::;::><:::.:.:<:::::::::>::::;: ........... .. .:.:::::.::.::.::::. BUILDING, ADJACENT'..... ..................- ...................... .......... ........ ............ RT BGI"t' C HALE,. >' ....................... ::.;:. % MUNICIPAL COURT U G ........::>::>:::....::::>::.........:. ............ The application(s) listed are in order of application number only and not nece e>fr[ tI B Qr'der<trt;wftrehi they will be heard. Items will be c:atled for hearing at the discretion of the Hearrtl EX2t11111Bt PROJECT NAME: New Safeway at NE 4th and Union Ave PROJECT NUMBER: LUA-93-148,SA,ECF,BSP DESCRIPTION: Site Plan Approval for development of up to 76,300 gsf of commercial space on an 8.07 acre site abutting the east side of the existing Safeway store. Three development phases are proposed: Phase I is a new grocery store of up to 62,500 gsf, and all site improvements including development of up to 475 parking spaces; Phase II is up to 6,000 gsf of retail shops to be located between the existing grocery store and Phase I construction; Phase Ill is a free standing commerical structure of up to 7,800 gsf, to be located adjacent to NE 4th. The existing grocery store will be redeveloped for non-grocery retail uses in the future and is not part of this application. GENERAL LOCATION: Approximately 400 feet east of NE 4th and Union Intersection PROJECT NAME: 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) PROJECT NUMBER: LUA-94-001,ECF,SP,SA,V,SM,CU PROJECT DESCRIPTION: The purpose of this proposed project is to complete the construction of P- 1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. GENERAL LOCATION: Springbrook Creek/SW Grady to SW 16th St. HEXAGNDA.DOC City of Renton PUBLIC Department of Planning/Building/Public Works HEARING PRELIMINARYREPORT TO THE HEARING EXAMINER A. SUMMARYAND PURPOSE OF REQUEST Public Hearing Date April 5, 1994 Project Name I405 Box Culvert/P-1 Channel Improvement(Springbrook Creek) Applicant City of Renton-Planning/Building/Public Works(Surface Water Utilities Section) File Number LUA-094-001,SA, ECF, Project Manager L. Blauman SP,V,SM,CU (Planning)S. Woodbury(Public Works) Project Description The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of Elie United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the I-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1405 box culvert forces the flow around the box culvert to the west and underneath the 1405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. Native vegetative cover will be provided on the shoreline, adjacent to the culvert to support/enhance the native environment. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. Project Location Springbrook Creek/SW Grady Way to SW 16th Street B. GENERAL INFORMATION.• I. Owners of Record City of Renton Arlene Haight, Property Management 200 Mill Avenue South Renton, WA 98055 King County Drainage District No. 1 Jack E. Nelson, Attorney 601 West Gowe Kent, WA 98032 Phone: 206-854-7200 WA State Dept. of Transportation (WSDOT) Robert A.Josephson, P.E. Manager of Planning& Local Coordination 15700 Dayton Avenue North, MS 122 P.O. Box 330310 Seattle, WA 98133-9710 Phone: 206440-4000 Group Health Cooperative Jim Douma, Property Management 521 Wall Street Seattle, WA 98121 Phone: 206448-4699 Bridge Group Don Moody, Western Pacific Properties 1400 112th Avenue SE, STE 100 Bellevue, WA 98004 Phone: 451-4811 Puget Western Don Moody, Western Pacific Properties 1400 112th Avenue SE, STE 100 Bellevue, WA 98004 Phone: 4514811 Boeing Company Andrew Clapham, Project Engineer P.O. Box 3707, MS 6W-90 Seattle, WA 98124-2207 Phone: 206-393-7072 Municipality of Metropolitan Seattle (METRO) Lynn Wilcox 821Second Avenue Seattle, WA 98104 Phone: 206-684-1284 2 �y 2. Zoning Designation Medium Industrial(IM)-1.2 acres between I405 and SW 16th Street Commercial Office(CO)-2.0 acres north of 1405 and south of SW 16th Street 3. Comprehensive Plan Employment Area, Industrial-0.4 acres between I405 and SW 1601 Land Use Designation Street and within east 1/2 of the SE 1/4 and NE 1/4 of Section 24, Township 23 North, Range 4 East, W.M. Employment Area, Office-2.8 acres 4. Existing Site Use The site is currently used as a stream corridor for conveying surface water runoff. The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1- 405 Oakesdale Avenue SW underpass on the east. 1405 runs east- west through the project area approximately 400 feet north of SW 16th Street. The project area is slightly north and east of the former Longacres racetrack site (including that portion now being; developed as the Boeing CSTC facilities), and slightly southeast of the METRO Wastewater Treatment Plant. The property to the north of 1-405 and west of the project channel is vacant land. A single family dwelling with horse pasture is to the west of the channel, south of 1-405, and north of SW 16th Street. S. Neighborhood Characteristics North Springbrook Creek flows north from the project area approximately 0.5-mile to its confluence with the Black River Pump Station (BRPS)forebay. The BRPS forebay is situated where the former Black River channel and Earlington Golf Course had previously existed. The BRPS forebay serves as a temporary storage pond for flows from Springbrook Creek and local tributaries, prior to the flows being pumped into the Black River discharge channel. The Black River then flows into the Green River to form the Duwamish River which flows into Elliot Bay of Puget Sound. To the north of the BRPS is the Black River Riparian Forest and the predominantly residential areas of Renton and Skyway. Sunset Boulevard(SR 900)is located approximately 1-mile north of the project site. East Industrial, office, and commercial uses predominate the valley area east of the project site. South The Boeing Customer Service Training Center(CSTC) and Renton- Kent Green River valley industrial and commercial land lie to the south of the project site. Large undeveloped areas predominate the area immediately south of the project. West The Metro Sewage Treatment Plant is immediately west and the Renton-Tukwila municipal boundary lies approximately 1/4-mile west of the project site. 3 r 6. Access The project area is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the I-405 Oakesdale Avenue SW underpass on the east. Limited access can be achieved via SW 16th Street and SW Grady Way. I405 runs east-west through the project area approximately 400 feet north of SW 16th Street. Because of its limited access requirements and elevated grade access from I-405 is not possible_ SW Oakesdale Avenue drops below surrounding grade as it passes under I-405 so access from this street is also not possible. 7. Site Area Site area: 3.25 acres C. HISTORICAL/BACKGROUND: Action Land Use File No. Ordinance No. Date Annexation NA 1745 4114/5 9 Annexation (Amend Ord. 1745) NA 1764 5/15/5 9 Annexation (Amend Ord. 1764) NA 1928 12/19/ 61 Rezone (T/G to L1;BI) R72-708 2767 3/14/' 3 Rezone(GSI to BI) R-79387 3360 10/10/ 79 Box Culvert CU/SM 88-088 NA 5/201 8 SW 16th Street Bridge SP/SM 88-033 NA 12/9/8 8 Rezone (B1;MP, OP to CO,IM) NA 4404 7/11/9 3 D. PUBLIC SERVICES: 1. Utilities Water Existing 12" distribution mains are located in SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. No new permanent water services arc required to serve the proposed development. Sufficient water for construction needs are available in the existing mains. A metered, temporary fire hydrant supply connection will be established for use during construction. 4 , Sewer Gravity sewer lines of various size are located in SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. The Metro 90" interceptor is located immediately west of the existing Springbrook Creek channel. Although no-new permanent sewer service is proposed for operation of the box culvert, temporary service from the Metro sewer may be established during construction. Groundwater withdrawn during dewatering operations may be discharged to the Metro sewer to reduce the potential for release of iron rich water into Springbrook Creek downstream of the project site. Surface Water/Storm Water The proposed project will increase the capacity of the existing Springbrook Creek channel through the project area. As needed during construction, flows in the existing channel will be temporarily bypassed around the construction site to maintain work areas in a sufficiently dry condition to accommodate construction activities. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. Existing underground gravity drainage lines of various size are located in SW Grady Way, Oakesdale Avenue SW, and SW 16th Street. Drainage into the existing Oakesdale Avenue SW underpass collection system must be pumped into Springbrook Creek because of the low elevation of the underpass. Approximately 60-feet of new 24" culvert is anticipated for the proposed pedestrian trail crossing associated with the trail alignment proposed along the west bank of Springbrook Creek. No other new permanent underground storm utility service is proposed. 2. Fire Protection Fire Protection is provided to the site per City of Renton Ordinance 3. Transit Metro Lines#163, #240, #280, #340, #912, and #966 provide access to the project site, thereby facilitating pedestrian access to the proposed Springbrook Trail facility. 4. Schools Not applicable 5 S. Recreation Existing public recreation facilities include the Springbrook Creek Trail, in place at various locations to the south of the site and to the north of the site(with additional trail segments planned under the Master Trails Plan, generally, and with a specific segment proposed in conjunction with the subject application). Similarly, bicycle lanes exist, or are planned, under the Master Trails Plan immediately in the vicinity of the project site. Green River Trail access and Fort Dent Park are located approximately.5 mile northwest of the site. The Cedar River Trail is located approximately .75 miles northeast of the site. Cedar River/Liberty Park is located approximately two miles northeast of the site. E. APPLICABLE SECTIONS OF THE ZONING CODE.• 1. Section 4-31-11.2 Medium Industrial Zone 2. Section 4-31-16 Commercial Office Zone 3. Section 4-31-36 Conditional Use Ordinance 4. Section 4-31-19 Variance Ordinance 5. Section 4-31-33 Site Plan Review Ordinance 6. Section 4-9 Land Clearing and Tree Cutting Ordinance 7. Section 4-22 Surface and Storm Water Management Ordinance 8. Section 4-31-34 Landscaping Ordinance 9. Section 4-31-31 Flood Hazards Ordinance 10. Section 4-10 Mining, Excavation and Grading Ordinance 11. Section 4-31-27 Zoning Ordinance (Special Permits) E APPLICABLE SECTIONS OF THE COMPREHENSIVE PLAN OR OTHER OFFICIAL CITY DOCUMENT- 1. City of Renton Comprehensive Plan(Land Use Element)- Chapter 5 -Employment Areas-Section II, Section III; Chapter 7-Open Space and Parks-Section II; Chapter 8-Environment -Sections I - IX; Chapter 9-Community Design-Section Vl, Section VII; Chapter 13-Utilities 2. City of Renton Comprehensive Plan (Interim Transportation Plan) 6 3. City of Renton Master Trails Plan 4. City of Renton Shorelines Master Program G. DEPARTMENTANALYSIS: 1. BACKGROUND: History: The East Side Green River Watershed Plan (ESGRWP), also known as the Valley Drainage Study, has a long history dating back to the early 1960's when the local governments of Auburn, Kent, Tukwila, Renton, King County Conservation District, and King County requested federal flood assistance from the Soil Conservation Service (SCS) under the Watershed Protection and Flood Protection Act (Public Law 566). The SCS developed a work plan in 1965 which was approved by the United States Congress. This led to the construction of the Black River Pump Station (BRPS) in 1972. In 1972 the National Environmental Policy Act (NEPA) was enacted and it was determined that :tn Environmental Impact Statement(EIS)would be required prior to any future project improvements. A draft EIS issued in 1973 raised concerns regarding the environmental impacts posed by the plan. It was not until 1978 that a revised watershed plan was completed which provided for a reduced scope of work to more accurately reflect development trends and to address environmental concerns. A NEPA EIS was then prepared by SCS and approved at the federal level in 19 7 9. Subsequent modifications to the 1978 revised watershed plan were finalized and approved by the local governmental sponsors along with an Environmental Mitigation Program in 1980. A 1981 amplification to the 1979 EIS was then prepared by the SCS to reflect the changes to the 1978 watershed plan. The plan consisted of constructing the P-1 Channel/P-9 Channel in the City of' Renton and a series of channels in the City of Kent. The total plan consisted of approximately 1 1.1 miles of new channels with the P-1 Channel being the main channel with an average top width of- 210 feet. In 1982 the local sponsors withdrew from the plan as a result of a disagreement over the equitable cost sharing for the local share of the plan construction cost. Following 1982, the City of Renton assumed lead agency responsibility from King County. With assistance from SCS the City of Renton constructed the BRPS forebay, the P-1 Channel from the forebay to SW Grady Way, and the S\1' Grady Way box culvert. Efforts to continue construction of the channel improvements identified in the watershed plan from SW Grady Way to SW 43rd Street were halted when City review of tl1c NEPA EIS determined that the document did not adequately evaluate the environmental impacts of the overall plan. However given that SCS support would be withdrawn if the City did not rely on the existing environmental documents, it was agreed, with Ecology approval, that the City proceed to adopt the NEPA EIS as a local. State Environmental Policy Act(SEPA) document. The process to formally adopt the NEPA EIS as a local SEPA document began in 1988. The adoption process generated serious concerns and comments from various regulatory agencies, environmental groups, and citizens who questioned the adequacy of the original NEPA EIS. The City Elicit suspended the adoption process and conducted an Adequacy Determination Study for the NFP.\ EIS. This study identified deficiencies in the NEPA EIS with respect to wetland impacts, impacts to streams, wildlife and fish habitat, and water quality. In addition, the existing hydrologic and hydraulic models were considered out of date due to changes in the drainage system and advances in modeling technology. Concurrently with environmental review of the NEPA EIS, the 1-405 box culvert, the Oakesdalc Avenue SW underpass, and the P-1 retaining wall projects were constructed in conjunction with tic state's I-405 HOV lane project. These projects were constructed without the corresponding channel improvement when concerns about the adequacy of the 1979 NEPA EIS halted efforts to continue construction of the channel improvements identified in the modified 1978 ESGRWP. The City elected to move forward with the construction of the I-405 culvert and P-1 retaining walls because these structural improvements would have been much more expensive if not done in conjunction with the HOV project. Until the 1979 NEPA EIS was determined to be inadequate as a local SEPA document, the SW Grady Way to SW 16th Street channel project was considered an integral segment of the system of improvements identified in the modified 1978 ESGRWP. However, the SW Grady Way to SW 16th Street improvement is now proposed to be implemented separately, but concurrently, with the effort to identify and evaluate future flood control alternative projects south of SW 16th Street in :in updated ESGRWP and EIS. The proposed channel project is then the final segment of channel improvements located north of SW 16th Street to be constructed in accordance with the modified 1978 ESGRWP and 1979 SCS NEPA EIS, as supplemented through the City SEPA process. Because the project and updated ESGRWP are independent and separate, approval of this project would not imply approval of any element of the updated ESGRWP effort. The proposed project impact evaluation and mitigation is considered independent from the updated ESGRWP because the project would not predetermine or depend on future improvements identified in the updated plan. The existing 1405, SW Grady Way, SW 16th Street, and Oakesclalc Avenue SW streets confine this project's segment of Springbrook creek to a narrow, defined corridor. Also, all downstream improvements and major structures necessary-for the proposed project have already been permitted and constructed. The impact evaluation and mitigation for the proposed project are identified in the SEPA checklist. For the updated ESGRWP there are several options for the location of future improvements south of SW 16th Street, as the location for these improvements is not so limited by existing streets and other existing development. Any future proposed alignment must be evaluated for impacts and compared with other alternative alignments through the updated ESGRWP for their effect on environmental resources. The proposed project, however, does not predetermine, depend upon. or foreclose opportunities for a future connection between this project segment and any future ESGRWP improvement, that potential connection being clearly defined by the existing channel location as it passes under the SW 16th Street bridge. The City has made significant progress toward an updated ESGRWP, and is committed to completion of the plan effort. A portion of the work was to be completed though the Black River- Water Quality Management Plan (BRWQMP) funded in part by a Centennial Clean Water Fund grant from Ecology. Ecology approval of the final BRWQMP plan has been received. Updated hydrologic and hydraulic models and summary reports, including a preliminary alternatives analysis have been sent to SCS for review. Work is in progress to address SCS comments on the models and to extend the period of simulation to include water years 1989-91, as well as the most recent information on regional storm water detention facilities, which were not included in the recent modeling work. Because of the major storm events in 1990-91, the flow predicted by the recent modeling work could increase up to 20%. The preliminary alternatives analysis will I)c reevaluated using the increased flows and the reports updated. The flood control alternatives will be finalized and integrated into an updated ESGRWP with other related information for SI:I'A review. Following the completion of land use review, final design of the project can be completc(l. The first phase of construction of the improvements to be identified in the updated ESGRWI) is expected to start in 1997. Current Project Proposal: Channel Improvements: The purpose of the proposed channel improvement project is to coml)lctc the construction the P-1 Channel improvements from SW Grady Way to SW 16th Street. Tile existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the I-405 box culvert However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the I-405 box culvert forces the flow around the box culvert to 8 the west and underneath the IA05 bridge adjacent to the box culvert. The existing channel is also too confined and may not be widened without undermining the existing pile supports for the I-405 bridge, which are not spaced sufficiently far apart to allow the existing channel under the bridge to be enlarged. Construction of the proposed improvements is planned now to improve the functioning of the channel. With the completion of the proposed project, the channel will provide increased floodwater conveyance through the existing Springbrook Creek flood control reach that is now too narrow for adequate floodwater passage. Native vegetation will be provided on the shoreline, adjacent to the culvert to support/enhance the native environment. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. Excavation associated with the project will provide an additional 4 acre-feet of floodwater storage. The risk of upstream flooding will be reduced by providing increased flow conveyance capacity and flood storage. The project improvements would also be beneficial to water quality by reducing; channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project site was selected based upon the following factors: 1) the proposed project improvement is needed as identified by the 1978 watershed plan and confirmed in recent analysis for the Cities of Renton and Tukwila; 2) the existing flood conveyance/control strttctttres :irc located at this site; 3) viable alternative uses for this site are limited by site characteristics (flood levels, steep slopes, and riparian habitat), by limited access, and by development restrictions established under the City's Shorelines Master Program and the Zoning Ordinance. Site evaluation included attention to the existing environment, identification of likely impacts to that environment, and formulation of measures to address anticipated environmental impacts. For example, the site is located in an area which includes floodplains and floodways; the subject parcels are identified as being within a floodway and/or within the floodplain. There is a small wetland on the project site, which is exempt from the Wetlands Management Ordinance, by virtue of size (.01 acre) and quality(Category III). The Department of Fisheries has indicated that Springbrook Creek supports runs of coho salmon and other anadromous fish including steelhead and cutthroat trout. Salmonids have been recorded migrating upstream at the Black River Pump Station. Project construction within the existing channel will require Springbrook Creek to be temporarily routed to bypass the work area while construction is in progress. This will temporarily prevent passage of fish through the channel within the project area. Also, during the construction process. the entire area of channel and pedestrian trail construction will be cleared of existing vegetation, resulting in temporary loss of the vegetative cover. Any birds, mammals, and other wildlife that have been observed on or near the site or are known to be on or near the site may be temporarily displaced by construction of the project. To address construction impacts of the proposed project on the natural and built environment, tltc time and extent of disturbance within the channel shall be kept to a minimum. The project dcsig n includes a plan for stabilization of the site during construction (e.g. seeding, rip rap, erosion cowrol blankets). Following construction, permanent plantings (trees, ground cover, seeding) will be introduced to reestablish vegetative cover removed by construction. Fish habitat enhancement components are included in the project design and consist of placing root wad and boulders groups in the low flow channel to create resting areas for migrating fish; plantings along the low Ilow channel will provide shading for migrating fish. Pedestrian Trail: The original application includes a pedestrian trail as a corollary development to, and in conjunction with, the development of the channel improvements. The purpose of the trail is to cross the IA05 corridor to provide a connective link along the Springbrook Creek Trail system (pedestrian and bicycle) to the north and south, which will provide increased public recreational opportunities. 9 The trail alignment proposed in the project application follows along the top of the west bank of the existing Springbrook Creek channel from the south side of SW Grady Way to about 80 feet north of SW 16th Street. The alignment of the remaining portion of the trail to SW 16th Street and the crossing may occur along one of two route options within a proposed corridor., The corridor extends from the west end of the SW 16th Street bridge to the first new Boeing CSTC driveway west of the bridge, and from the.terminus of the proposed trail about 80 feet north of SW 16th Street to the southern edge of the SW 16th Street right-of-way. The two options considered are: 1) a crossing opposite the Boeing CSTC shoreline trail; or 2) a crossing at the first Boeing CSTC driveway intersection west of the SW 16th Street bridge. The crossing alternative to be constructed will be selected by the City in a planned study of the crossing alternatives. The property rights for the portion of this alignment not on City property were proposed to be acquired in the form of.] permanent easement. However, because of the potentially high cost of acquiring the property rights necessary to establish a trail link across I-405 on the west bank of Springbrook Creek, and because connection of the trail to SW 16th Street could not be made until concerns with the location of the SW 16th Street crossing were resolved through further study, it was decided to reconsider other trail alignments for crossing the I405 corridor. The recommended alternative to the west bank trail provides for a 7-foot wide pedestrian/hicycle facility to be constructed along the west side of the Oakesdale Avenue SW underpass. This proposed alignment includes a reduction in the width of all the existing five traffic lanes of' Oakesdale Avenue SW through the 1405 underpass and may require the area to be posted as a bicycle dismount zone. This alignment was selected to be included in the City's pending six-year Transportation Improvement Program for implementation. Negotiations for the property rights needed for the west bank alternative are continuing. However. if agreement cannot be reached on the terms of the acquisition or if an acceptable crossing location of SW 16th Street cannot be identified, then the west bank alignment may be abandoned. Both alignments are considered in this report and each are proposed to be consistent with the City's Master Trails Plan, with the Shoreline Master Program, and with other City regulations as applicable. NOTE: Throughout the following sections of this report the two alignments are referenced as Elie "west bank alignment" and the "underpass alignment." Variance: The proposed project includes construction activity/improvements within 25 feet of the ordinary high water mark of a segment of Springbrook Creek from SW 16th Street to SW Grade Way. The Land Clearing and Tree Cutting Ordinance (Section 4-9-5.13) prohibits activity within this 25 foot corridor- The applicant is seeking a Variance to permit removal of vegetation, filling/grading and replacement of vegetation, as necessary to support the proposed channel improvements and a pedestrian trail (public access) in accord with the policies and regulations of' the Shorelines Master Program. Special Permit: The City's Mining, Excavation and Grading Ordinance (4-10) and the.Loning Ordinance (4-31-27) require a Special Permit for the mining, excavation and/or grading of more than 500 cubic yards of soil. The proposed development includes the excavation of approximately 15,700 cubic yards of soil and the introduction of approximately 8,100 cubic yards of soil. Permit Requirements: For the proposed box culvert project (including restoration of the vegetam,c cover and development of a trail) to be constructed, the applicant will need to obtain a Conditional Use Permit, a Site Plan Approval, a Special Permit, a Shorelines Substantial Development Permit, and a Variance. The Conditional Use Permit is required for the channel improvements, based upon 01C definition of the proposed project as a "medium" utility. A Site Plan Approval is required for the proposed trail system. The Special Permit is required for site preparation for the channel improvement and the trail. A Shorelines Substantial Development Permit (SSDP) and a Variance (from the Land Clearing and Tree Cutting Ordinance) are necessary to allow the channel improvements and the trail(west bank alignment only)along the shoreline of Springbrook Creek. 10 NOTE: The Hearing Examiner will review the Conditional Use Permit, the Site Plan Approval, the Special Permit, and the Variance application. Background information concerning the shorelines permit request will be presented to provide context; the Administrator of the Planning/Building/Public Works Department will act upon the SSDP in accordance with the provisions of the State Shoreline Management Act (RCW 90.58) following the decision by the Hearing Examiner on the Conditional Use Permit, the Site Plan Approval, the Special Permit and the Variance application. 2. SEPA REVIEW: The Environmental Review Committee (ERC) issued a Determination of Non- Significance on February 2, 1994. Comments were received during the SEPA comment period; the documents were installed in the record, and the content of the comments has been incorporated, as applicable, into the proposed project. No appeals were filed during the SEPA appeal period. 3. DEPARTMENTAL COMMENTS: Various City departments have reviewed and commented on the proposal. Comments have been generally favorable to the proposed project These comments have been installed in the project record and incorporated into the proposed project, as applicable. Staff comments are also attached to this report. 4. CONDITIONAL USE PERMIT: A Conditional Use Permit is required under Section 4-31-11.2 (Medium Industrial Zone) and the Commercial Office Zone (4-31-16) which describe a "medium" utility as an Administrative Conditional Use. The Interim Zoning Ordinance (4-31-2) defines :t "medium utility" as a "moderate scale facility) serving a sub-area of the city, including power lines, water transmission lines, sewer collectors and pump stations...". The proposed development is considered to be a medium utility, as the planned channel improvement will serve to convey storm drainage from the sub-area of the City within the Black River Basin. An administrative conditional use permit is typically reviewed by the Site Plan Review Committee. however, as the Hearing Examiner is required to review the Special Permit;and the Variance, and is conducting a hearing for Site Plan Approval for the pedestrian trail, a determination was made by staff to request that the Hearing Examiner review the Conditional Use permit as well. Section 4-31-36 lists 11 criteria that the Hearing Examiner is asked to consider, along with all other relevant information, in making a decision on a Conditional Use application. These include the following: A. Comprehensive Plan: The proposed use shall be compatible with the general purpose, goals, objectives and standard of the.Comprehensive Plan, the "Zoning Ordinance and any other plan, program, map or ordinance of the City of Renton. 1. Comprehensive Plan Based upon the purpose and design of the project, consistency is achieved with the overall goal of Chapter 8, Environment, of the Interim Land Use Element of the Comprehensive Plan (Renton, 1993), which calls for "continue(I protection of Renton's natural systems, natural beauty, and environmental quality." Chapter 8 (Sections II-VIII)also establishes policies designed to ensure that development is sensitive to and enhances the natural environment. In compliance with those policies, the project is designed for multiple use and benefit with the inclusion of elements such as: 1) fish and wildlife habitat plantings and structures, 2) low flow fish passage channel, 3) regrading and armoring of existing severely eroded stream banks, 4) high flow conveyance and stora('c within the new and existing channels for increased flood protection, 5) preservation of the existing channel for off-stream fish and wildlife habitat, and 6) inclusion of a pedestrian trail link for recreational opportunities and public access to the shoreline. Specifically, the project is consistent with the applicable objectives and policies of Chapter 8, as follows: Policy EN4.1: "Manage water resources for multiple uses including recreation, fish alld wildlife, flood protection, erosion control, water supply, energy production, and opeii space"(emphasis supplied). tt Policy EN-5.2: "Degraded channels and banks should be rehabilitated by public programs and new development"(emphasis supplied). Policy EN-8.1: "Maintain and enhance natural drainage systems to protect water quality, reduce public costs, and prevent environmental degradation." Policy EN-8.2: "Preserve natural surface water storage sites that help regulate service flows and recharge groundwater"(emphasis supplied). Objective EN-9.0: "Provide a storm and surface water control and drainage system capablc of preventing threats to life, property and public safety during a 100 year flooding event." Policy EN-9.4: "Manage the cumulative effects of storm water though a combination of' engineering and preservation of natural systems." Objective EN-10.0: "Provide for, and work toward, a regional approach to stormwatcr management programs." The project is a joint effort of the City of Renton and the U.S.D_A. Soil Conservation Service (SCS). The project is approximately 75% funded by SCS through the Watershed Protection and Flood Protection Act(Public Law 566). Objective EN-14.0: "Protect and enhance wildlife habitat through the City." Policy EN-17.6: "Incorporate design elements which preserve and enhance the natural drainage system into developments in an effort to control erosion and sedimentation." Similarly, the project is consistent with applicable sections of Chapter 5 (Employment Areas), Chapter 7 (Open Space and Parks), Chapter 9 (Community Design) and Chapter 13 (Utilities). 2. Zoning Ordinance: The project is permitted as a Conditional Use in the underlying Medium Industrial (IM) and Commercial Office (CO) Zones. The planned channel improvements are also compatible with applicable development standards within the IM and CO zones. For example, the existing channel improvements, which were authorized as a principal use when initially developed, have become an existing non-conforming use with adoption of the Interim Zoning Code. Under this Interim Zoning Code, the proposed medium utility improvement is a Conditional Use. The granting of the Conditional Use permit at this time would replace the "non-conforming use" designation and would result in a conforming use status for the project, facilitating maintenance and upgrading as needed in the future. For example, the IM zone (Section 4-31-11.2 D.5) calls for those portions of sites not covered with structures, or their appurtenances, to be maintained as permeable areas and improved with native, drought resistant vegetative cover (grasses, shrubs) and with replacement/addition of native trees in numbers and at locations similar to the existing vegetative cover. The proposed development includes a combination of planting and seeding to reestablish vegetative cover removed by construction immediately upon completion of construction upon affected segments. A compatible, but non-native plant. the Bankers dwarf willow (salix cotteti), which has been approved by the Department of' Fisheries for use in this area for similar projects, is proposed to be planted along the proposed low flow channel. The dwarf willow was selected because it does not develop into a large tree that would present an obstruction to the flood conveyance capacity of the channel, but will temporarily lay over during times of high flow. The dwarf willow also provides shade and visual screening for the low flow channel, reducing the potential for solar exposure and providing shelter for migrating fish. 12 The wildlife planting proposed with the project covers a 3200 square foot area, in satisfaction of the 2% landscaping requirement (for wildlife habitat) required for development in the Green River Valley in the Development Standards section of the lull zone (RMC 4-31-11.2.D). In accordance with City requirements, a maintenance bond will be posted as surety that any needed maintenance of installed improvements will be performed. This planting plan achieves compliance with the development standards for the IM and CO zones. Similarly, the project, as proposed, is consistent with the standards for sensitive areas established in the IM and CO zones (Section 4-31-16 D.9), including, but not limited to Section 4-31-31 (Flood Hazards), based upon the fact that the purpose of the project is to achieve flood control, and Section 4-31-34 (Landscaping), based upon the revegetation plan. (Also see "Sensitive Areas Ordinance" below) Other development standards for these zones are applicable to other types of land use developments and do not apply to this project. 3. Sensitive Areas Ordinance: The project is consistent with the applicable requirements of the Flood Hazards and Landscaping sections of the Zoning Ordinance as follows: a) Flood Hazards (RMC 4-31-31, Section G.3.a) states that "encroachments...and other development...shall not result in any increase in flood levels during the occurrence of the base flood discharge." The project, as proposed, will exceed this requirement, by reducing the flood levels upstream of the project. Similarly, the proposed project will address, through the construction and restoration plans (including rip rap structures and revegetation), the ordinance requirement (Section F4) calling for "the faces of cut and fill slopes (to) be developed and maintained to control against erosion. This control may consist of' effective planting. Where necessary...rip rap or other devices or methods shall be employed...". b) Landscaping (RMC 4-31-34). "Any development in the Green River Valley shall provide a minimum of two percent (2%) of the total site for landscaping suitable to wildlife habitat" (Section F2). The wildlife planting area proposed for the project meets this 2% requirement. 4. Shoreline Master Program. The proposed development requires a Substantial Shorelines Development Permit, by virtue of the fact that the project site incorporates portions of Springbrook Creek and its associated floodway/floodplain areas. The multiple uses planned for and improvements included with the proposed project (described in Section G.1 above) are consistent with the goals and policies of the Shoreline Master Program, as described below: "Preference should be given to those uses or activities which enhance the natural amenities of the shorelines and which depend on a shorelines location or provide public access to the shorelines" (Section 4.01.02.A.2). The project depends upon the proposed shoreline location because the existing channel improvements are located here and because 111c surrounding streets (I-405, SW Grady Way, SW 16th Street, and Oakesdale Avenue Sw) confine Springbrook Creek within the project area to a narrow, defined corridor. Ali alternative location for the new channel is not available outside of the proposed project area. Also, all downstream improvements and major structures necessary for the proposed project have already been permitted and constructed. The pedestrian trail component of the project provides public access to the shoreline. 13 "Existing natural resources should be conserved" (Section 4.02.02.A). The existing channel under I-405 will be preserved to provide off-stream fish and wildlife habitat. The channel will also provide four (4) acre-feet of additional flood water storage, as well as additional conveyance capacity. The plantings and structural features described in Section G.A.1. and G.A.2. above also serve to implement this policy. "The City of Renton should take aggressive action with responsible governmental agencies to assure that the discharges from all drainage basins are considered an integral part of shoreline planning" (Section 4.02.02.C). Regulations pursuant to Stream Alteration (Section 7.16.03) permit such alteration where the project is demonstrated: (a) to be necessary; (b) to employ timing and methods which will have minimal adverse effects on aquatic life; (c) to minimize pollution during and after construction; and (d) to maintain low flow to allow the escapement of fish." The proposed project is an essential element of a regional system of storm drainage facilities that convey basin discharges and provide flood control protection to the public. The project will be constructed with the support and assistance of SCS. The time and extent of disturbance within the channel shall be kept to.a minimum. For example, to minimize the impact of temporarily preventing passage of fish through [Ile channel, construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. Because of uncertainties regarding weather and on-site conditions, extension of the fisheries window up to October 15 may be necessary to complete construction. Any extension request will be coordinated with the City and the Department of Fisheries. The project design includes a plan for stabilization of the site during construction (e.g. seeding, rip rap, erosion control blankets). Following construction, permanent plantings (trees, ground cover, seeding) will be introduced to reestablish vegetative cover removed by construction. Fish habitat enhancement components are included in the project design and consist of placing root wad and boulders groups in the low flow channel to create resting areas for migrating fish; plantings along the low flow channel will provide shading for migrating fish. Approximately 55 working days are estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. Section 7.18 (Utilities) of the SMP calls for the maintenance/restoration of native vegetation in conjunction with utility construction (Section 7.18.01). As noted in the preceding section, following construction, the site will be restored/enhanced with native vegetation, except for the planting of dwarf willows along the low flow channel. Section 7.18.03.D. calls for pedestrian public access to publicly owned shorelines. The proposed public access trail addresses this specification. NOTE: Information concerning the relationship of the project to the Shorelines 'Master Program is provided solely for the purpose of addressing criterion GA.A. Review of [lie discrete application for a SSDP will be addressed by the Administrator of dic Planning/Building/Public Works Department in accordance with the provisions of the State Shoreline Management Act (RCW 90.58). 5. City of Renton Master Trails Plan. The project proposes a trail link across the I- 405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, thus providing a planned segment of the Springbrook Valley Trail identified in the Master Trails Plan. This plan is consistent with Policy 7 of the Master Trails Plan, which calls for development to "address 'micro' level trails and fill in gaps in existing trail patterns where appropriate". 14 B. Community Need: There shall be a community need for the proposed use at the proposed location. In the determination of community need, the Hearing Examiner shall consider the following factors, among all other relevant information: (1) The proposed location shall not result in either the detrimental overconcentration of a particular use within the City or within the immediate area of the proposed use. The additional medium utility use proposed to be provided in the Green liver Valley is necessary to provide increased flood control protection at this location, to address public health, safety and welfare. The proposed storm water management system is planned to serve as :in improvement of an existing management system at the project site. The project is limited to a 3.25 acre site and to an area in which improvements already exist, for • the purpose of limiting an,overconcentration of such utility systems within the Green River Valley. (2) That the proposed location is suited for the proposed use. The proposed channel improvements are considered to be appropriate for the planned location, as these improvements are intended to upgrade an existing Springbrook Creek channel that flows through the project site. This channel reach is the only outlet for a 22 square mile tributary drainage area and, thus, cannot he abandoned. The new channel segment to be constructed with the proposed project, which is adjacent to and includes portions of the existing channel, will create an additional (expanded) medium utility between the existing channel and the I405 Oakesdalc Avenue SW underpass. The new channel utilizes a narrow strip of land area, which by its location(lack of access), development standards for the underlying IM and CO zoning (e.g. use limitations, setback requirements), and Shorelines Master Program regulations, is not appropriate for commercial or industrial use. With the proposed development, the site will be enhanced to provide a riparian corridor for fish and wildlife habitat. C. Effect on Adjacent Properties: The proposed use at the proposed location shall not result in substantial or undue adverse effects on adjacent property. The proposed project is a regional flood control improvement designed to increase the level of flood control protection currently provided by the existing channel for all property upstream of the project reach. The proposed project would provide many benctits including increased flow conveyance capacity and flood storage as well as alleviation of :ui existing erosion problem. The project completes the channel improvements for which [lie existing 1-405 and SW Grady Way box culverts, P-1/Oakesdale retaining wall, and SW 16111 Street bridge capital improvements were designed. The project utilizes land area, which by its location and zoning designation, provides no opportunities for land development, but will be enhanced to provide a riparian corridor for fish and wildlife habitat, and will, as well, provide an improved viewscape for passers-by. These improvements would also he beneficial to water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. The project will also provide for a trail link across the I-405 corridor to connect the existing and proposed pedestrian and bicycle trails to the north and south, which will result in increased recreational and educational opportunities consistent with the Shoreline Master 15 Program goals and policies. The project increases the public accessibility to the shoreline, but preserves and improves the existing amenities(e.g. riparian habitat). (1) Lot Coverage: ...Lot coverage ... shall conform to the requirements of zone in which the proposed use is to be located. This criteria is not applicable to any of the proposed project channel improvements. (2) Yards: Yards shall conform to the requirements of the zone in which the proposed use is to be located. This criteria is not applicable to any of the proposed project channel improvements. (3) Height: Building and structure heights shall conform to the requirements of the zone in which the proposed use is to be located. ...heights should be related to surrounding used in order to allow optimal sunlight and ventilation, and minimal obstruction of views from adjacent structures. Optimal sunlight and ventilation would be permitted and views in the vicinity of the ' project would not be altered or obstructed, as the proposed channel improvements are located within the channel area below surrounding grades. D. Compatibility: The proposed use shall be compatible with the residential scale and character of the neighborhood. (Ord 3599, 1-11-82) The proposed development site is located in an area zoned for commercial, office and/or industrial uses (CO, IM). Existing development in the vicinity is predominantly commercial, office, industrial and/or public use facilities (e.g. sewer treatment facilities). There are a small number of residences in the area of the site; these are typically non-conforming uses. The proposed development is considered to be compatible with the underlying land uses. For example, the existing Springbrook Creek system is linear in shape and the land area currently subject to its use will not be significantly increased by the project. The additional medium utility use will create no structures above ground level to interfere with views. Restoration of vegetation, enhancement of riparian habitat, and provision of a pedestrian trail is considered to be an amenity for near-by residents, for employees of offices, industrial plants, and commercial developments, and for passers-by. In addition, benefits to local residential and non-residential developments will result from the increased flood control protection occurring with the proposed channel improvements. E. Parking: Parking under the building structure should be encouraged. Lot coverage may be increased to as much as seventy-five percent (75%) of the lot coverage requirement of the zone, in which the proposed use is located, if all parking is provided underground or within the structure. (Ord.3903, 4-22-85) This criteria is not applicable as the project does not proposes to provide any parking facilities. F. Traffic: Traffic and circulation patterns of vehicles and pedestrians relating to the proposed use and surrounding area shall be reviewed for potential effects on, and to ensure safe movement in the surrounding area. This criteria is not applicable to operation of the proposed medium utility, as use of the Site for the proposed channel improvement will not generate additional traffic. 16 Note: Traffic and circulation patterns associated with site preparation are reviewed under the Special Permit evaluation (G.7). Traffic and circulation patterns associated with the proposed pedestrian trail plan arc reviewed in the Site Plan Approval evaluation (G.5). G. Noise, Glare: Potential noise, light and glare impacts shall be evaluated based on the location of the proposed use on the lot and the location of on-site parking areas,outdoor recreational areas and refuse storage areas. Operation of the channel, as proposed, will occur within the channel area below surrounding grades and will not create noise or glare impacts. Note: Noise and glare impacts associated with site preparation are reviewed under the Special Permit evaluation (G.7). Noise associated with construction and operation of the proposed pedestrian trail plan are reviewed in the Site Plan Approval evaluation (G.5); no glare impacts are anticipated from the trail, as there will be no lighting fixtures installed on the trail. H. Landscaping: Landscaping shall be provided in all areas not occupied by building or paving. The Hearing Examiner may require additional landscaping to buffer adjacent properties from potentially adverse effects of the proposed use. The proposed development includes a combination of planting and seeding over the 3.25 acre project site, including wildlife planting proposed with the project which covers a 3200 square foot area, in satisfaction of the 2% landscaping requirement (for wildlife habitat) required for development in the Green River Valley The purpose of this plan is to sustain permeable shoreline areas and the stream bed will) improved native, drought resistant vegetative cover (grasses, shrubs) and with replacement/addition of native trees (with the exception of the non-native dwarf willow proposed for along the low flow channel and used successfully downstream of the project area) in numbers and at locations similar to the existing vegetative cover. (Also see Sections G.1 and GA.A.2). I. Accessory Uses: Accessory uses to conditional uses such as day schools, auditoriums used for social and sport activities, health centers, convents, preschool facilities, convalescent homes and others of a similar nature shall be considered to be separate uses and shall be subject to the provisions of the use district in which they are located. This criteria is not applicable as no accessory uses are proposed. J. Conversion: No existing building or structure shall be converted to a conditirn,al use unless such building or structure complies, or is brought into compliance, with the provisions of this Chapter. This criteria is not applicable as no conversion is proposed. K. Public Improvements: The proposed use and location shall be adequately served by and not impose an undue burden on any public improvements, facilities, utilities, and services. Approval of a conditional use permit may be conditional upon the provision and/or guarantee by the applicant of necessary public improvements, facilities, utilities, and/or services. A portion of the proposed channel is directly adjacent to the Oakesdale Avenue SW underpass and underdrain system. The capacity of the underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, niay he 17 ry overburdened by the short circuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. In order to prevent piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the channel membrane will be connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. With the above described underdrain improvement plan, the additional medium utility use to be provided by the proposed channel improvements will not impose undue burden on any existing public improvements, but will provide increased flood control protection to the public. No additional public improvements, facilities, utilities, and/or services are required to permit the proposed channel improvements to function effectively. Because of the proximity of excavation to the Municipality of Metropolitan Seattle (METRO) sewer interceptor pipeline and Washington State Department of Transportation_(WSDOT) I- 405 structural improvements the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. 5. SITE PLAN APPROVAL The Site Plan Review Ordinance (4-31-33) and the ordinances which address the underlying zoning (IM and CO) call for site plan approval for the development of' the public access trail (secondary use) planned as a corollary development to the channel improvements. A public hearing is typically not required for site plan review of a secondary use in the IM and CO zones that would otherwise be exempt from the site plan review requirements. However, as the Hearing Examiner is required to review the Special Permit and the Variance, a determination was made by staff to request that the Hearing Examiner review the site plan as well. As discussed in Section G.1, the report discusses two trail alignments designed to provide a link across the I-405 corridor to connect into the existing and proposed Springbrook Creek Trail (pedestrian and bicycle) to the north and south and provide increased public recreational opportunities. These alignments are the "west bank alignment", located along the west,bank of the existing Springbrook Creek, and the "underpass alignment", located along the west side of Oakesdale Avenue SW through the 1-405 underpass. Under Section 4-31-33, "(t)he Hearing Examiner and City staff shall review and act upon site plans based upon comprehensive planning considerations and the following criteria: A. Conformance with the Comprehensive Plan, its elements and policies; Based upon the proposal for purpose, design, and location of the public access trail, this public amenity is considered to be consistent with the Interim Comprehensive Plan Land Use Element (Chapter 7-Section 2). For example, the trail plan is consistent with: Objective OS-6.0 "Develop and maintain a comprehensive trails system which provides non- motorized access throughout the City, maximizes public access to open space areas, and provides increased recreational opportunities for the public." Policy OS-6.1 "The trail system should serve local and regional users and be linked to the regional trail system." Policy OS-6.2 Trails should provide for the needs of a diverse population of users including groups such as adults, children, seniors, workers, the handicapped and other people ... including: pedestrians, bicyclists, joggers/runners...". Policy OS-6.3 "The trail system should be recognized and maintained by the City..." 18 Policy OS-6.6 "Within the City, linkages should be provided among...employment areas, Centers and recreation areas." In addition the trail plan is consistent with the policies established in the Comprehensive Parks Plan and the Master Trails Plan(see Section GA.A.5). B. Conformance with existing land use regulations; The location, design and landscaping of the pedestrian trail alignments are established so that compliance is achieved with the applicable ordinances, including the Zoning Ordinance (Section 4-31-11.2 [IM], Section 4-31-16 [CO]); the Landscaping Ordinance (4-31- 34), and the Shorelines Master Program(Sections 4-6 and 7.17). For example, Section 4-31-11.2 (IM) permits trails as a secondary use, subject to site plan approval and subject to consistency with the Comprehensive Parks Plan and Trails Master Plan. Staff note that trails in the IM zone are intended to be developed in conjunction with a permitted use and operated primarily for employees of the industrial zone. The proposed trail segment is not constructed in conjunction with a traditional, principally permitted industrial use, but is intended to provide a public trail linkage which facilitates trail enjoyment by employees of nearby industrial uses, such as Rabanco and the METRO Sewage Treatment Plant. Section 4-31-16(CO)also permits trails as a secondary use, subject to site plan approval and subject to consistency with the Comprehensive Parks Plan and Trails Master Plan. This use is permitted based upon community need. The proposed trail is intended to provide a public trail linkage which facilitates trail enjoyment by members of the local community throughout the Valley. In addition, the trail would serve local industrial center employees and employees of nearby commercial office developments, such as Boeing CSTC, and the Washington Technical Center. Similarly, the planned trail alignments, which will provide public access to the shoreline in the project area, is consistent with Shorelines Master Program (SMP) policies and regulations. For example, Policy 4.01.02 A.2 call for public access to the shorelines. Section 4.04.01 calls for an "(i)ncrease public accessibility to shorelines, and preserve and improve the natural amenities." Section 4.06.02.0 states that "(p)edestrian and bicycle pathways...should be developed." Section 7.12 of the SMP permits trail uses within the shoreline when the following standards are met: "Provisions for maintenance operation and emergency gecess have been provided." Access to the west bank alignment is to be provided via SW 16th Street and SW Grady Way for maintenance and emergencies. Access from Oakesdale Avenue SW is available for the underpass alignment as well. The City will maintain the trail. The trail "link(s)water access points along the shoreline or link(s) water access points along the shoreline with upland(s)." Both alignments for the proposed trail will link with existing shorelines trail segments and will connect to upland areas via the SW 16th/SW Grady Way/Oakesdale connections. The trail is "designed to avoid conflict with private property rights and to create the minimum objectionable impact on adjacent property owners...insure(s) the rights and privacy of the adjoining property owners.." The trail is planned to be located on property owned by the City of Renton. The trail is to be designed and sited to be consistent with trail segments adjacent to other private properties. Location and design is intended to 19 minimize visual and use obstruction to nearby residential and commercial properties and public uses. The trail is "designed with a surface material which will carry...user loads and will have a minimum impact on the environment." The trail will be constructed of asphalt, in keeping with other trail segments, on west side of Springbrook Creek. Segments located under the Oakesdale Avenue overpass will be concrete. Native vegetation plantings planned for the trail corridor address basic landscaping requirements for type, quantity, size and location of plantings, as established in the Landscaping Ordinance. In addition, the trail planting plans are consistent with the requirements for an additional two percent of landscaping for wildlife habitat, required by the Landscaping Ordinance, for development in the Green.River Valley. Also see Section G.4.2-5, G.S.0 and G.S.D. C. Mitigation of impacts to surrounding properties and uses; The project will also provide for a trail link across the I-405 corridor to provide a connective segment along the Springbrook Creek Trail (pedestrian and bicycle) to the north and south, which will provide increased public recreational opportunities. The underpass alignment, planned to be located on the west side of Oakesdale Avenue SW, requires a reduction in the width of all five of the existing lanes through the 1-405 underpass. However, the City already has the property rights needed for its construction. The west bank trail alignment, planned to follow along the top of the west bank of the existing Springbrook Creek channel, requires acquisition of a permanent easement over the portion of the alignment not already on City property and presents a greater impact to adjacent property owners than the underpass alignment. Vegetation removed for trail construction will be restored as nearly as practicable to original condition as found immediately before commencement of the work. The potential for soil erosion associated with any clearing of vegetation for both the west bank and the underpass alignments, as authorized by the requested variance (west bank alignment only) will be minimized and mitigated as noted above for the channel portion of the project. In evaluating the potential impacts of the proposed trail to surrounding properties, staff' addressed the following pertinent criteria: 1. Mitigation of undesirable impacts of proposed structures and site layouts that could impair the use or enjoyment or potential use of surrounding uses and structures and of the community. The proposed open asphalt or concrete, landscaped trail for the west hank alignment and underpass alignment are planned to be coordinated in terms of design and location with surrounding land uses. There will be no visual obstructions. Light and air circulation will be maintained to the site and nearby properties. The trails are intended to serve as a public amenity; no use conflicts are anticipated to occur. 2. Provision of a desirable transition and linkage to trail systems in the surrounding area by the arrangement of landscaping (natural characteristics) and/or other buffering techniques, in order to prevent conflicts and to promote coordinated and planned benefit from, and access to, such elements. Trail location and landscaping improvements are designed to be consistent Nvith other segments of the Springbrook Creek Trail system. Access to the trail for risers 20 from surrounding developments and for community members will be facilitated by linkages to existing trail segments (e.g. the portion of the trail abutting Boeing CSTC)and to the public right-of-way(SW 16th Street/SW Grady Way). 3. Public benefit and desirability of maintaining visual accessibility to attractive natural features. The trail alignments, as proposed along the shoreline of Springbrook Creek, are designed to be as visually accessible to the Creek as site conditions permit. Similarly, the vegetation plan is designed to allow views of the Creek to be maintained to surrounding upland and shoreline private and public properties, and to passers-by traveling along Oakesdale Avenue, SW 16th Street, SW Grady Way, and I-405. D. Mitigation of impacts of the proposed site plan to the site; The pedestrian trail, as described generally in Section G.1 and more specifically in Section G.S.C. above, is considered in evaluating the impacts of the project to the development site, as based upon the following pertinent criteria: 1. Development placement and spacing to provide for privacy and noise reduction; orientation to views and vistas and to site amenities, to sunlight and prevailing winds, and to pedestrian ... needs; and 2. Consideration of placement and scale of proposed structures in relation to the openness and natural characteristics of a site, and 3. Consideration of building form and placement and landscaping to enhance year-round, conditions of sun and shade both on-site and on adjacent properties. The pedestrian trail (with the west bank alignment or the underpass alignment) is designed and located to be sufficiently separated from nearby land uses and rights- of-way to permit appropriate separation to facilitate a sense of privacy/defensible space and to create noise attenuation for both trail users and occupants of adjacent properties. The proximity/orientation of the trail (with either alignment) to vegetated corridors and to Springbrook Creek allows trail users and users of nearby properties to enjoy, the natural characteristics of the site, attractive views and relatively open vistas. Observation of wildlife habitat (fish, waterfowl, small mammals) should be facilitated by the restoration/enhancement of the underlying habitat. The open construction of the trail with either the west bank or the underpass alignment enables users to enjoy sunlight, air, and prevailing winds. There will be no interference with light and air circulation to neighboring properties. 4. Preservation of the desirable natural landscape through retention of existing vegetation and limited soil removal, insofar as the natural characteristics will enhance the proposed development; and 5. Use of existing topography to reduce undue cutting, filling and retaining walls in order to prevent erosion and unnecessary storm water runoff, and to preserve stable natural slopes and desirable natural vegetation. Soil excavation, filling and grading will be required to prepare to install the paved trail, with either the west bank alignment or the underpass alignment (also scc 21 Special Permit-Section G.7.A). This activity will be restricted to the minimum level necessary to provide adequate support for this facility. Native vegetation will be restored/enhanced adjacent to the trail alignments, upon completion of trail construction, pursuant to the Landscaping Ordinance (4-31-34) and the Shorelines Master Program. The vegetation base will be enhanced to provide the additional two percent of plantings required to support the wildlife habitat(Section 4-31-34). 6. Limitation of paved or impervious surfaces, where feasible, to reduce runoff and increase natural infiltration; Trail surfaces (with the west bank alignment or the underpass alignment) will be paved with asphalt (with street connections being paved with concrete) in order to ensure a level and safe travel corridor for pedestrians. The relatively narrow paved area (maximum 14 feet in width) is the minimum necessary to protect public safety and to facilitate upkeep/maintenance. The limited paved area is designed to minimize changes in storm water run-off patterns and volumes, and, therefore, will not result in significant increases in runoff or decreases to natural infiltration, consistent with the requirements of Section 4-22. 7. Design and protection of planting areas so that they are not susceptible to damage from vehicles or pedestrian movements; Landscaping plans (vegetation species and location of plantings) are designed to allow maximum visibility from the trail, with either of the proposed alignments and plantings are located to minimize interference with use of the trail, with either alignment, thus limiting opportunities for conflicts with pedestrian movements. Private vehicles will not be permitted to use the trail, with either alignment. Tile only vehicles which may access the trail are City maintenance vehicles or emergency vehicles. Vehicular use is expected to be infrequent. E. Conservation of area-wide property values; The proposed trail (with either alignment) as a part of the City's Springbrook Creek Trail system, is considered to be a public improvement, and, as such, should serve to maintain (or, perhaps, to increase)area wide property values. F. Safety and efficiency of vehicle and pedestrian circulation; Staff reviewed impacts related to vehicle and pedestrian circulation related to both construction and operation impacts from the trail, with either alignment. Hauling of materials during construction could have impacts on traffic in the project vicinity. Construction impacts are addressed in Section G.7.13 below. Operations impacts are reviewed herein. In evaluating the consistency of the operation of the proposed trail (under the west bank or underpass alignments) with this criterion, staff addressed the following sub-criteria: 1. Provision for safe and attractive pedestrian connections between the trail, public sidewalks and adjacent properties; and 2. Promotion of the safety and efficiency of the internal circulation system, including the location, design and dimensions of pedestrian access points, walkways, bikeways, and emergency access ways; 22 For both the west bank and the underpass alignments, widening of the existing sidewalk and new sidewalk improvements are proposed at the southwest corner of the SW Grady Way and SW Oakesdale Avenue intersection to connect with the proposed pedestrian trail and to provide sufficient waiting area at the existing intersection crosswalk. For the west bank alignment, no additional new sidewalk is proposed on the north side of SW 16th Street to discourage pedestrian use of the north side where there are no existing sidewalks or other marked crossings to travel to in the immediate vicinity. Mitigation for the west bank alignment is expected to include a marked crosswalk and pedestrian crossing traffic control signal constructed at SW 16th Street to connect with the sidewalk and shoreline trail under construction as part of the Boeing CSTC project. The final SW 16th Street crossing alternative and mitigation measures to be constructed will be determined by the City in a planned study of the crossing alternatives. For the options considered in the proposed project documents the following measures were anticipated by the applicant: 1) provide a pedestrian traffic signal and marked crosswalk of SW 16th Street, 2) construct signage in advance of the crossing to warn motorists of its location, and 3) modify the SW 16th Street and SW Oakesdale Avenue intersection to a three way stop to eliminate the free southbound right turn from SW Oakesdale Avenue onto SW 16th Street. For the west bank alignment, acquisition of a 15-foot permanent easement for the trail link is proposed to secure the necessary rights to allow public use. The easement will primarily follow the existing channel and minimize the area impact on the adjacent properties. Only the 80 foot segment directly north of SW loth Street may have a greater land area impact if the crossing will be constructed at tllc Boeing CSTC driveway. This is because of its increased distance from the channel compared to the option of crossing opposite the shoreline trail south of SW l6th Street. For the underpass alignment, the needed property rights are owned by the Cite. The underpass trail provides for a 7-foot wide pedestrian/bicycle facility to he constructed along the west side of the Oakesdale Avenue SW underpass. This proposed alignment includes a reduction in the width of all the existing five traffic lanes of Oakesdale Avenue SW through the I-405 underpass and may require the area to be posted as a bicycle dismount zone. The alignment would utilize the existing crosswalk and signal at SW Grady Way. A marked crosswalk would he provided at SW 16th Street. G. Provision of adequate light and air, The proposed development is an open space trail. The vegetative cover planned in the vicinity of the trails has been designed to ensure that the trail, with either the west bank or underpass alignment receives adequate natural light and air. No artificial illumination is planned for the trail, with either alignment. H. Mitigation of noise, odors and other harmful or unhealthy conditions; Staff reviewed impacts related to noise, odors and other harmful or unhealthy conditions related to both construction and operation impacts from the trail alignments. Construction activities could create noise, odor, dust, debris, light and glare impacts in dic project vicinity. Construction impacts are addressed in Section G.7.D. below. The trail is restricted to daytime use and use by pedestrians only. No noise, odor or other impacts are anticipated in conjunction with customary use of the trails. Noise Conu-ol 23 Regulations restrict use of equipment (such as radios); the City will enforce the Noise Control Regulations if violations occur. I. Availability of public services and facilities to accommodate the proposed use; The proposed trail, with either the west bank or the underpass alignment, will not impose undue burden on any existing public improvements. No additional public improvements, facilities, utilities, and/or services are required to permit the proposed channel improvements to function effectively. J. Prevention of neighborhood deterioration and blight. The proposed trail, with either the west bank or the underpass alignment, would be a part of the City's Springbrook Creek Trail system, and, as such, is considered to be a public improvement, and, as such, should not result in neighborhood deterioration and blight. 6. VARIANCE APPLICATION: The proposed channel improvement plans (and ancillary trail plan for the west bank alignment only) include the removal of existing vegetation, the excavation, filling and grading of portions of the site, and the replanting (replacement/enhancement) of vegetation (trees, shrubs, ground cover) within 25 feet of the ordinary high water mark of a segment of Springbrook Creek from SW 16th Street to SW Grady Way. Under the City's Land Clearing and Tree Cutting Ordinance (Section 4-9-5.13), "No tree cutting or land clearing is permitted within ... twenty five feet (25')of the ordinary high water mark of creeks..." The proposed project does not qualify as an exempt enhancement activity according to the definition in Section 4-9-3 of the Ordinance. Therefore, a variance is requested to allow removal/restoration of vegetation in those portions of the project site that are within 25 feet of the sensitive areas listed in Section 4-9-5.D. The Variance Ordinance (Section 4-31-19F) lists four criteria that the Hearing Examiner is asked to consider, along with all other relevant information, in making a decision on the Variance application. A. That the applicant suffers undue hardship and the variance is necessary because of special circumstances applicable to subject property, including size, shape, topography, location or surroundings of the subject property and the strict application of the zoning code is found to deprive subject property owner of rights and privileges enjoyed by other property owners in the vicinity and under identical zone classifications; The applicant is constrained by a series of special circumstances applicable to the proposed use(improvements to an existing storm water management/flood control system) and to the affected subject property(which is linear and confined)' Strict application of the Ordinance would prohibit any work adjacent to/within a creek, wetland, or shoreline in support of regional or local flood control facilities required to mitigate the expected cumulative effects of increased runoff volumes or flows to that sensitive area. These facilities are necessary to address cumulative effects resulting from existing or permitted upstream land use development (and resulting increases in impervious land area) within the City and in neighboring communities. Development-related impacts, if unmitigated, will increase flooding, erosion, sedimentation, and other related environmental impacts and costs in downstream streams and wetlands. Similarly, the Ordinance would prohibit regrading of a segment of the existing stream bank. within the proposed project area, that has been eroded to a near vertical slope and is unstable. 24 Strict application of the Ordinance, therefore, inhibits management of the City's stormwater and related environmental resources necessary to promote the public health, safety, and general welfare of the citizens of Renton. B. That the granting of the variance will not be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity and zone in which the subject property is located; The completed channel improvements, if constructed as proposed under the Variance application, will not be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity and zone in which the subject property is located, based upon the project development plan (including design, siting and construction plans) and mitigation measures as described herein (Section G.1; GA, G.5 and G.7) and in the Environmental Review Committee Report/Mitigation Measures Document (dated 2/2/94). Construction activities occurring adjacent to Springbrook Creek, could result in transient deleterious impacts, but these impacts are not either anticipated to be materially detrimental, based upon the project development plan (including design, siting and construction plans) and mitigation measures as described herein (Section G.1; G.4., G.5 .111d G.7) and in the Environmental Review Committee Report/Mitigation Measures Document (dated 2/2/94). For example, soil erosion could occur in conjunction with vegetation removal and site preparation (excavation, filling, grading) within the Springbrook Creek channel, as the entire area of the channel and pedestrian trail construction will be cleared of existing; vegetation. Shoreline anchoring provided by the riparian trees, shrubs, and grasses will be temporarily lost. To minimize this potential for soil erosion, the disturbed area within the existing channel will be kept to a minimum. Site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. Erosion that could occur during rain and/or wind storms during the construction phase of the project will be minimized as, in general, earthwork activities would be done during a period of dry weather(June-September/October). The contractor will be required to submit an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. The construction contractor will be required to control erosion from the proposed project site by employing erosion control measures in accordance with City of Renton standards and other acceptable best management practices (BMP's). Erosion and sedimentation controls, such as straw bale barriers, silt fences, and straw mulch for temporary protection of exposed, soils should be applied during; construction. Stabilized construction entrances and washpads should be installed at the beginning of construction and maintained for the duration of the project. All measures shall be installed and maintained in accordance with local, state, and federal requirements. Also, the removal of riparian vegetation within 25 feet of the Creek, under the requested Variance, will result in a temporary loss of habitat. However, the existing vegetation is neither diverse nor of significant structure; the habitat which is supported by this vegetation is limited. The trees to be removed are small and, at generally 6" in diameter, arc the minimum size regulated under the Ordinance. Removal of the trees and other riparian vegetation will be mitigated by providing surface cover protection to disturbed areas immediately upon achieving final grade or, in advance, as conditions (e.g. weather patterns) warrant. The project is designed, when complete, to include a combination of plantings and rip rap, to minimize the erosion potential after construction. 25 S With the proposed Variance, the project does not include the introduction of any improvement in the floodway that will increase the risk of flooding upstream of the project area. Instead the project removes restrictions from the floodway and reduces the risk of upstream flooding by.providing increased flow conveyance capacity and flood storage as well as alleviation of an existing erosion problem. The project, with the proposed Variance, rather than resulting in material detriment, would provide public benefit. For example, from the proposed project would result in improved water quality by reducing channel erosion, maximizing biofiltration, and reducing exposure to solar induced temperature increases. With the proposed variance, construction activities would be confined to areas, both within and outside of the 25 foot setback corridor, which cannot be developed, due to a variety of constraints. Site characteristics (flood levels, steep slope, and riparian habitat) constrain developable areas. Use of the land within the project area is also limited by its proximity to the existing Springbrook Creek channel and the associated setback provisions of City Codes for any development along that channel. Use options are also restricted by limited access. For example, due to disparate elevations of 1405 (elevated grade) and Oakesdale Avenuc (below grade), access to the site is not available from either of those roadways. Access is not possible from SW 16th Street or SW Grady Way to the project area east of the existing.; channel because the depth and sensitive nature of the existing channel would restrict crossing opportunities. Because of this limited access to the project area, the proposed channel utilizes land area which is of no commercial use, but can be enhanced to provide a riparian corridor for fish and wildlife habitat. The project, with the proposed Variance, will also provide for a trail link across the I-405 corridor to provide a connective segment along the Springbrook Creek Trail (pedestrian and bicycle) to the north and south, which will provide increased public recreational opportunities. C. That the approval shall not constitute a grant of special privilege inconsistent .vith the limitations upon uses of other properties in the vicinity and zone in which 111c subject property is located situated; To date, public and private development projects requiring relief from the strict interpretation of the Land Clearing and Tree Cutting Ordinance have been eligible for exemption from Ordinance provisions. As a result of this situation, there is no opportunity to rely upon precedent to support the proposed variance. Staff consider, however, that the proposed Variance is necessary and prudent to provide for the improvements required to the existing flood control channel to achieve regional flood control, and, therefore, to benefit the public interest in general, and to provide improved development opportunities for private properties throughout the Green River Valley. Staff consider that the Variance, as proposed, for the purpose of improving an existing public facility, does not offer a grant of special privilege but rather enables a necessary public benefit. Further, the Variance Ordinance offers a future opportunity for applicants to seek similar variances for development of projects to achieve a public or private benefit. D. That the approval as determined by the Examiner is a minimum variance that will accomplish the desired purpose. Granting of the variance provides relief from the provisions of Section 4-9-5.D that .vould prohibit land clearing and tree cutting associated with the proposed channel improvements. Other provisions of the Ordinance will remain in full force and effect. a. 26 Granting of the variance also provides relief from the provisions of Section 4-9-5.1) that would prohibit land clearing and tree cutting associated with the proposed west bank trail alignment. The alignment primarily follows the existing channel to minimize the area impact on adjacent property. Maintenance vehicle use is expected to be infrequent and so the waste material associated with vehicular use will not be significant. Vegetation removed for the trail construction will be restored as nearly as practicable to original condition as found immediately before commencement of the work. The potential for soil erosion associated with any clearing of vegetation for the trail as authorized by the requested variance will be minimized and mitigated as noted above for the channel portion of the project. Other provisions of the Ordinance will remain in full force and effect. 7. SPECIAL PERMIT: The applicant is seeking a Special Permit (Mining, Excavation and Grading Ordinance - 4-10) to allow excavation and grade/fill activities in order to prepare the site for the above-described development. Under Section 4-31-27 of the Zoning Ordinance and the Mining, Excavation and Grading Ordinance 4-10-3(B)(2), a series of basic criteria is established to be used by the Hearing Examiner to determine whether _the proposed excavating and filling operations are compatible with existing/planned future land uses. (In addition to achieving compatibility with these below-listed criteria, the applicant will be required to comply with all provisions of the underlying Mining, Excavation and Grading Ordinance and with conditions established by the Environmental Review Committee). The criteria are: A. Size and Location of the Activity Approximately 15,700 cubic yards of soils are planned to be excavated on the 3.25 acres project site, of which approximately 2100 cubic yards would be removed from the area within the ordinary high water mark of Springbrook Creek. New fill is proposed to be introduced, in the amount of 8,100 cubic yards, of which 1700 cubic yards are to be introduced into the area within the ordinan, high water mark of Springbrook Creek. An additional 500 cubic yards of fill will be needed to support each of the proposed trail alignments. The purpose of the fill/grade activities is both stabilization of upland areas and filling of a small Category III wetland (which is exempt by virtue of size and quality from the Wetlands Management Ordinance), in order to provide a suitable base for the planned channel improvements, for the restoration of plantings to the project site, and for the pedestrian trail alignments. Any construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Depending upon the timing for issuance of the Corps of Engineers Section 404 individual permit and uncertainties regarding weather and on-site conditions, it may be necessary to request that the Department of Fish and Wildlife extend the constnuction winclow beyond September 15, 1994, as conditions permit. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. The project contractor will prepare a construction mitigation plan outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. 13. Traffic Volumes and Patterns In conjunction with proposed disposal and fill activities, an estimated 1000 truck trips (averaging 40 trips per day) to/from the site are anticipated to occur over a period of approximately 10 weeks, assuming use of truck/trailers capable of hauling approximately 17 cubic yards of material. Transportation impacts (e.g., traffic volumes, haul routes, noise, dust and debris) related to these site preparation activities will be addressed in the required construction mitigation plan, which 27 includes the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. Because of the proximity of excavation to the Washington State Department of Transportation (WSDOT) I-405 structural improvements the applicant and construction contractor shall coordinate with WSDOT as applicable. C. Screening, Landscaping, Fencing and Setbacks Based on the location of the proposed preparation activities, adjacent to Springbrook Creek, wetlands and to working rights-of--way, and the scope of the fill plan, screening is necessary during preparation activities(Section 4-10-11). D. Unsightliness, Noise and Dirt The proposed site preparation activities may result in an unsightly environment, and will create dust and dirt, noise and glare. Soil Erosion: Soil erosion could occur in connection with the construction of the proposed project, since the entire area of channel and pedestrian trail construction will be temporarily cleared of existing vegetation. Erosion could occur during rain and/or wind storms that occur during the construction phase of the project. As required by City regulations, the applicant will submit prior to construction an erosion control Flan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. The project design includes a combination of plantings, seeding, rip ral), and erosion control blankets to minimize the erosion potential after construction. The plan shall be based on the King County Surface Water Design Manual, as adopted by the City of Renton. The contractor will also be responsible for addressing any state and federal permit conditions required for the project. All required sedimentation/erosion control facilities must be constricted and in operation prior to clearing and/or other construction to minimize discharge of sediment laden water from the project site. The time and extent of disturbance within the.channel shall be kept to a minimum to minimize erosion impacts and to minimize temporary displacement to wildlife. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design. In general earthwork activities should be done during period of dry weather. Any construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance local, state, and federal permit conditions. Depending upon the timing for issuance of the Corps of Engineers Section 404 individual permit and uncertainties regarding weather and on-site conditions, it may be necessary to request that the Department of Fish and Wildlife extend the construction winclow beyond September 15, 1994, as conditions permit. Approximately 55 working days is estimated to be needed from the start of excavation to establishment of final grade and permanent stabilization. As noted above the contractor will prepare a construction mitigation plan outlining in detail the construction schedule and phasing for review and approval of the City and project engineer. The time and extent of disturbance within the channel shall be kept to a minimum. Disturbed areas will be seeded immediately following construction. Seeding shall be started as soon as definable segments of the excavated channel are completed as determined by the Engineer. 28 Permanent seed mixtures shall be applied between April 1 to October 15. Winter seeding shall be applied outside the permanent seeding dates as needed, and followed with permanent seeding the next spring as approved by the Engineer. Following permanent seeding, a portion of the area outside the low flow channel that was disturbed during construction will be,covered by an excelsior blanket for erosion control and to aid vegetative establishment. As construction progresses and unexpected or seasonal conditions dictate, the contractor shall anticipate that more erosion and sedimentation control facilities will be necessary to insure complete siltation control on the project site. It shall be the obligation and responsibility of the contractor to revise or modify the erosion control facilities to meet any new conditions that may he . 'created by construction activities and to provide additional facilities, over and above minimum requirements, as may be needed to protect adjacent properties and water quality of the receiving drainage system. It is possible that project excavation activities may unearth cultural resources, although mach of the project area has been significantly disturbed by past construction for the adjacent local streets and I- 405 freeway. The individuals involved in construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City of Renton, and the Washington State Historic Preservation Officer to determine the course of action. The herein identified impacts are considered by staff to have been addressed, in part, in the applicant's proposed construction management plan and in conditions established by the Environmental Review Committee for management of fill/grade activities. Because of the proximity of excavation to the Municipality of Metropolitan Seattle (METRO) sewer interceptor pipeline the applicant and construction contractor shall coordinate with METRO as applicable. Noise and Glare: Noise and glare impacts could occur in conjunction with operation of equipment during construction of the channel improvements and the pedestrian trail. In accordance xvidi contract requirements, normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and niaY be subject to the City Noise Control Regulations and other conditions. The required construction mitigation plan, which includes the construction schedule and phasing, the hours of operation, the haul route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. The construction mitigation plan will include provisions for advance notification of the construction schedule to owners of near-by properties and other provisions as needed to minimize the impact of construction on the occupants of the existing house adjacent to and west of the project area. Also, compliance with Mining, Excavation and Grading Ordinance requirements for screening and planting the site during and following preparation activities should serve to maintain [lie appearance of the site and should control public health/welfare impacts. E. Surface Water The site is located in the Black River Drainage Basin (in an area which is in a floodplain/floodwaN' and where the water table is within a few feet of the surface). Because work areas must be sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel, Springbrook Creek will be temporarily routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. 29 ti Ground water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. The groundwater may be rich in dissolved iron, which may be oxidized upon exposure to air and settle out of solution to produce a rust colored plume downstream of any groundwater discharge point. This will temporarily reduce the aesthetic value of the affected area which will return to original condition over time. Conceptual fill/grade plans submitted by the applicant, mitigation measures established by ERC,,and Code requirements (e.g. Mining, Excavation and Grading Ordinance, Surface and Storm Water Management Ordinance) serve to ensure that site preparation activities do not negatively impact the Drainage Basin (including, but not limited to Springbrook Creek, surrounding floodplains and upland areas). Under the required Construction Mitigation Plan, the applicant will submit a bypass plan outlining the proposed sequence and timing of any surface water bypass. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. The disturbed area within the existing channel and other areas of the project will be kept to a minimum. For example, to minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance with permit conditions to he established by the Washington State Department of Fisheries. Depending upon the timing for issuance of the Corps of Engineers Section 404 individual permit and uncertainties regarding weather and on-site conditions, it may be necessary to request that the Department of Fish and Wildlife extend the construction window beyond September 15, 1994, as conditions permit. It is anticipated that construction of the channel north and south of I-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the hydrometerological conditions, such as precipitation levels, at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. The bypass plan shall include a backup system for maintaining or supplementing the function of:in%, water bypass should the primary diversion fail or function inadequately. The bypass must be capable of handing mainstream Springbrook Creek flows of a minimum of the 2-year recurrence interval or design storm, a flow of 455 efs (R.W. Beck, 1991). The plan is also to include an emergency monitoring and contingency plan for work within the channel. The plan will outline measures to implement for immediate stabilization of disturbed areas at risk to flow of water, should the bypass system 2-year design capacity be in danger of being exceeded. Under the required Construction Mitigation Plan, the applicant will submit a dewatering plan outlining the proposed dewatering extent, sequence, and timing. All ground water withdrawals arc to be directed, if conditions permit, into the METRO sanitary sewer, temporary settling pond, or other device to minimize the discharge of iron rich water into Springbrook Creek. F. The Length of Time the Application of an Existing Operation has to Comply with Non-Safety Provisions of this Ordinance. Not applicable. G. Reuse of the Site This site is not intended for development. if. Protection of the Public Trust Dredging or other construction disturbance as part of this project could cause contaminated sediments that may be already existing in the project reach to be suspended and carried downstream. Contaminants that may be in the dredge spoils could also be a potential health risk it not disposed of properly. Although previous sampling at SW 16th Street indicated that contaminants in the sediment at that location were below Model Toxics Control Act (MTCA) 30 cleanup regulation levels and special disposal of the sediments would not be required, further assessment of the site is being conducted. Herrera Consultants was contracted to test a surface sample and a sample at one foot depth at a total of four locations within the project area. The field work was completed at the end of September, 1993, and a report of the results was received in February, 1994. The findings of the report indicate that no additional pollutants are found to exceed MTCA levels. Additional testing may be necessary depending upon the requirements for use of the dredge material disposal site agreed upon by the disposal site's owner. The disposal site will be identified in the construction mitigation plan. If monitoring reports indicate that sediments arc found to exceed MTCA levels, the applicant will dispose of the sediments in accordance with MTCA regulations. The subject proposal, as supplemented by the mitigating measures established by the Environmental Review Committee, is not anticipated to result in a burden on public services. Similarly, the above-described mitigation measures/conditions for site preparation and subsequent construction (or hydroseeding) should ensure that the permitted site preparation activities do not harm the persons or property, and, therefore, would not be detrimental to the,public interest. !-L RECOMMENDATIONS.- Staff recommend that the Hearing Examiner approve the development (File 001-94) proposed by the City of Renton Storm Water Utilities Division, including a: (1) Conditional Use Permit for construction of the improvements to the P-1/Springbrook Creek Channel; (2) Site Plan Approval for the Springbrook Creek pedestrian trail; (3)Variance from the Land Clearing and Tree Cutting Ordinance; and (4) Special Permit for site preparation, with the following conditions: 1. The applicant shall comply with the conditions established by the Environmental Review Committee in the Determination of Non-Significance issued on February 2,1994. 2. The applicant shall provide a Construction Mitigation Plan, to the satisfaction of the Planning/Building/Public Works Department, prior to receiving construction/development permits for the proposed development. 3. The applicant shall develop the proposed channel improvements in the manner, and in accord witli the plan established in the application materials of January 1994. In the event that there is a substantial change required to the project description or to the construction plan, the applicant shall notify the Development Services Division. Amendments to the project plan must be approved by the City. 4. A representative identified by applicant shall provide a specific trail plan and construction schedule in accord with the City's Master Trails Plan and the pending City's Transportation Improvements Program (1995-2000), to the satisfaction of the Planning/Building/Public Works Department, prior to the issuance of construction/building permits for the proposed trail improvement. 31 vV t'CCIV 1 VI4 DETERMINATION OF NON-SIGNIFICANCE (MITIGATED) APPLICATION NO(S): LUA-94-001,ECF,SP,SA,V,SM,CU APPLICANT: City of Renton, Surface Water Utility PROJECT NAME: 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) DESCRIPTION OF PROPOSAL: The purpose of this proposed project 'is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22.square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. LOCATION OF PROPOSAL: Springbrook Creek/SW Grady to SW 16th St. LEAD AGENCY: City of Renton Department of Planning/Building/Public Works Development Planning Section The City of Renton Environmental Review Committee has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21 C.030(2)(c). Conditions were imposed as mitigation measures by the Environmental Review Committee under their authority of Section 4-6-6 Renton Municipal Code. These conditions are necessary to mitigate environmental impacts identified during the environmental review process. The 15 day comment period for this project will end on February 22, 1994. Following the end of the comment period, the City will finalize its Determination unless comments received require a reevaluation. Following the finalization of the Determination, there is a required 14 day appeal period of which you will be notified. Appeal procedures and the mitigation measures imposed by the City of Renton's Environmental Review Committee are available at the Development Services Division, Third Floor, Municipal Building, Renton, Washington 98055. Phone: 235-2550. You should be prepared to make specific factual objections. PUBLICATION DATE: February 7, 1994 DATE OF DECISION: February 2, 1994 SIGNATURES: Gre g Zimme'fman, interim Administrator DATE Department of Planning/Building/Public Works Sam Chastain, Administrator DATE Community Service Department Lee Wheeler, Fire Chief DATE Renton Fire Department ONSMSIG.DOC LJL- I L.I\IVI11\P, -FIN VI 11 1 MITIGATION MEASURES APPLICATION NO(S): LUA-94-001,ECF,SP,SA,V,SM,CU APPLICANT: City of Renton, Surface Water Utility PROJECT NAME: 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) DESCRIPTION OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil.Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. LOCATION OF PROPOSAL: Springbrook Creek/SW Grady to SW 16th St. MITIGATION MEASURES: The Environmental Review Committee issued a Determination of Non- Significance - Mitigated with the following Mitigation Measures: 1. To address construction impacts of the proposed project on the natural and built environment, the applicant shall submit a construction mitigation plan for approval of the City and SCS. 2. To minimize the potential impact of temporarily routing Springbrook Creek to bypass the work area and implementing dewatering operations while construction is in progress within the existing stream channel, the applicant shall submit a bypass plan and dewatering plan for approval. 3. To address construction impacts of the proposed project on the natural and built environment, the time and extent of disturbance within the channel shall be kept to a minimum. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design, such as seeding, plantings, rip rap, and erosion control blankets. 4. To minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to the period between June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. 5. In order to determine if pollutants that may be in sediments to be removed during the project are below levels requiring special disposal and/or if additional sediment testing is required, the applicant shall submit a sediment monitoring report to the City and SCS for review. 6. To minimize potential impact to cultural resources that may be present in the project area, the individuals involved with construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City, and the Washington State Historic Preservation Officer to determine the course of action. Advisory Notes to Applicant: The following notes are supplemental information provided in conjunction with the environmental determination. Because these notes are provided as information only, they are not subject to the appeal process for environmental determinations. 1. In accordance with standard contract requirements, normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. The construction mitigation plan should include advance notification and other provisions as needed to minimize the impact of construction on the occupants of the existing house adjacent to and west of the project area. 2. To minimize the potential for impact to existing structures, the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. 3. The mitigation measures included in this determination were proposed by the applicant in the project application documents. It is the responsibility of the applicant to ensure that all mitigation is implemented as proposed, and that any additional information requiring review is submitted and approved prior to construction. mitmeas - 1 - 02/03/94 City of R,,rton Department of Planning/Building/Public ..'orks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT: a u-}-t`� COMMENTS DUE: .JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM,CU DATE CIRCULATED: ON APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 JM J 7 Springbrook Creek 199 LOCATION: Springbrook Creek/SW Grady to SW 16th St. Rl IIL1.,_. vtyty SITE AREA: 3.25 acres ` BUILDING AREA(gross): SUMMARY OF PROPOSAL The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major Information Impacts Impacts Necessary Impacts Impacts Necessary Earth Housing Air Aesthetics water Light/Glare Plants Recreation LandrShoreline Use Utilities Animals Transportation Environmental Health Public Services Energyl HistorWCultural Natural Resources Preservation /UG C0A1B. POLICY-RELATED COMMENTS !n. 11\4 CITE qF A9 NTON C. CODE-RELATED COMMENTS We have reviewed this applica0on with particular attention to those areas In which we have expertise and have identified areas of probable impact or areas where additional Information is needed to property assess this proposal. Signature of Director or Authorized Representative Da� OEVAPO COC City of k.,lton Department of Planning/Building/Public ..orks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT: p ,� - COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM.CU DATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, B1auni`itQ%LN3U= d 1N?NIdCI?n�r. PROJECT TITLE: 1-405 CulverUP-1 Channel Improvement WORK ORDER NO: 79728 Springbrook Creek t r.,re LOCATION: Springbrook Creek/SW Grady to SW 16th St. it SITE AREA: 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major Information Impacts Impacts Necessary Impacts impacts Necessary Earth housing Ali Aesthetics Water UghtlGlare Plants Recreation LandIshom ine Use Utilities Animals Transportation Environmental Health Public Services Energy/ HistonclCultural Natural Resources Preservation B. POLICY-RELATED COMMENTS C. CODE-RELATED COMMENTS We have reviewed this application with particular attention to those areas in which we have expertise and have identified areas of probable impact or areas where additional information is needed to property assess this proposal. Siena ure of 0"ector Authored Representative Date City of r._,iton Department of Planning/Building/Public, .Jorks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENTChs Volt COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM,CU DATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 CITY OF RENfON S rin brook Creek LOCATION: S rin brook Creek/SW Grady to SW 16th St. SITE AREA: 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the construction of 1RUtlbbli►9LkrW[qK � from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvementsole Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element or the Probable Probable More Element of the Probable Probable More Environment Minor Major information Environment Minor Major Information Impacts impacts Necessary Impacts impacts Necessary Earth Housing Air Aesthetics water Light/Glare Plants Recreation Lardshoreline use utilities Animals Transportation Environmental Health Public Services Energyr Histoncicuiturai Natural Resources Preservat/on GSV E�C'°MEN, C/T yCF;jFN7-0NN'NG B. POLICY-RELATED COMMENTS C. CODE-RELATED COMMENTS We have reviewed this appGcadon iytth particular attention to those areas in which we have expertise and have iden0ed areas of probable impact or areas wnere addrUo nfo do i;n to propeq assess this proposal. Signs r of Director or Authorized Representative Date 0--VAfP DOC Re iC193 City of R,.,ton Department of Planning/Building/Public .vorks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT: —t? l� � COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA V,SM,CU DATE CIRCULATED: q 1t t= APPLICANT: Cityof Renton Surface Water Utilities PROJECT MANAGER: WooA9 ''St'U►rlarlAt EPT u PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 _ S rin brook Creek LOCATION: S rin brook Creek/SW Grady to SW 16th St. SITE AREA: 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile ,watershed (Exhibit B). directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major Information Impacts impacts Necessary Impacts Impacts Necessary Earn Housing Air Aesthetics WaterLight/Glare Plants Recreation LandShomilne Use utilities Animals Transportation Environmental Health Public Services Energy/ HislondCultural Natural Resources Preservation B. POLICY-RELATED COMMENTS , ; y C. CODE-RELATED COMMENTS � T / lea I/I/C/,/I �ntcr ��1�� C7 C GefSS c� a,l ,y We have reviewed this application with particular attention to those areas to which we have expertise and have identified areas of probable impact or areas where additional formation is need properly assess this proposal. l Signature of rector or Authorized Repre ntathve Date / R~ CEvAPP COC ' City of Fi.,iton Department of Planning/Building/Public .✓orks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET aC REVIEWING DEPARTMENT: W ViNkAe% COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM,CU DATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 Springbrook Creek LOCATION: Springbrook Creek/SW Grady to SW 16th St. SITE AREA: 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major information Impacts Impacts Necessary impacts Impacts Necessary Earth Housing _Zr- Aesthetics Water Light/Glare Plants Recreation LandrShcrellne use utilities Animals Transportation Environmental Health Public Services Energy/ HistoriclCultural Natural Resources Preservation B. POLICY-RELATED COMMENTS JAN 7 i9�4 :ITY�;r nEivTGN C. CODE-RELATED COMMENTS We have reviewed this application with particular attention to those areas in which we have expertise and have identified areas of probable impact or areas wnere additional in/orrnation is needed to property assess this proposal. Signature of Director or Authorized Representative Dat ;:EVaPPOOC City of Rei iton Department of Planning/Building/Public �vorks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT- � �Z"Cl,,^ COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM,CU DATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culveft/P-1 Channel Improvement WORK ORDER NO: 79728 CITY OF RENTON Springbrook Creek RECEIVED LOCATION: Springbrook Creek/SW Grady to SW 16th St. JM 0 7 1994 SITE AREA 3.25 acres I BUILDING AREA(gross): B r„ E)I rva SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1405 box culvert forces the flow around the culvert to the west and underneath the 1405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major Information Impacts Impacts Necessary Impacts Impacts Necessary Earth Housi Air Aesthetics water LightlGlars Plants Recreation LantYShoreline Use Utilities Animals Transportation Environmental Health Public Services Energy/ Historwcuttural Natural Resources Preservation ivo ,aypv��r cv.vF-��cT B. POLICY-RELATED COMMENTS JAI`I DEVELOF'',,ENT L ANNiIYG CITY OF RENTON C. CODE-RELATED COMMENTS we have reviewed this application with particular attention to those areas In which we have expertise and have identiiled areas of probable impact or areas weere additional information is needed to property assess this proposal. Signature of Director or Authorized Representative D e Rev tONJ ZEVAPo CCC City of k_ .on Department of Planning/Building/Public )rks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT: WWkC_y1_ COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA V,SM,CU DATE CIRCULATED: APPLICANT: Ci of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 S rin brook Creek CITY OF l�EAIfON HEXCEIVED LOCATION: S rin brook Creek/SW Grady to SW 16th St. SITE AREA 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the constructiolfj ag gents from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of o e en s to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit 8). directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Ma/or Information Impacts Impacts Necessary Impacts Impacts Necessary Earth Housing Air Aesthetics Water Light/Glare Plants Recreation Lar4lshorehne Use Utilities Animals Transportation Environmental Health Public Services Energyf Historic/Cultural Natural Resources Preservation 1A1 l,C 1410 I)t4A l. ic -i/i zc'E� Cs� T1�%� o FFi - A c c CG�l.�t'c=z is ,ccv/cI, y c B. POLICY-RELATED COMMENTS 0IT`/i-IF REN'ON C. CODE-RELATED COMMENTS We have reviewed this application with particular attention to those areas in which we have expertise and have identified areas of probable impact or areas wnere addroonal information is needed to property assess this proposal. �. ,A,I CV I/I t, /ut Signature of Director or Authorized Representative Date OEVADA DOC Rw 1M3 City of 1.-.)ton Department of Planning/Building/Public. .forks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET REVIEWING DEPARTMENT: kz�uelp N`oz _RaMk1A6OMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA V,SM,CU ATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury, Blauman PROJECT TITLE: 1-405 Culvert/P-1 Channel Improvement WORK ORDER NO: 79728 S rin brook Creek LOCATION: Springbrook Creek/SW Grady to SW 16th St. SITE AREA 3.25 acres I BUILDING AREA(gross): SUMMARY OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert. Constalction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be estabHto the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS 91 Element of the Probable Probable More Element of the Probable t WOF jA&UIN Environment Minor Major Information Environment Minor �1 RE 4rrffmado n Impacts impacts Necessary Impacts Impacts Necassary Eanh housing Au Aesthetics Water Light/Glare Pl a nts Recreation Land/Shcreline Use utilities Animals Trans nation Environmental Health Public Services Energy/ HistohdCultural Natural Resources Preservation �6 �ti//•j �r's�aa�w/�!l r'/rc/rGQfv F/ov /'aGct G���':.�, �ti� o-f�r ,.7a.>�Lrs� is o�G.�-� �✓y a�Q�pG� O /k�ir-i�� p�tiv .i2ry (��fi r,!/4iGi'td�'r rdGlit!a.�K II�G�Cs, B. POLICY-RELATED COMMENTS C. CODE-RELATED COMMENTS we have reviewed this appficadon with particular attention to those areas in which we have expertise and have identified areas of probable impact or areas where additionallnformadon is needed to propehy assess this proposal. Signature of Director or A razed Representative Date -CVAPP OCC Rev. t0/93 L City of Renton Department of Planning/Budding/Public v.orks ENVIRONMENTAL & DEVELOPMENT APPLICATION REVIEW SHEET. REVIEWING DEPARTMENT: F-w6 COMMENTS DUE: JANUARY 21, 1994 APPLICATION NO: LUA-94-001,ECF,SP,SA,V,SM,CU DATE CIRCULATED: APPLICANT: City of Renton Surface Water Utilities PROJECT MANAGER: Woodbury. Blaum PROJECT TITLE: I-405 CUlvert/P-1 Channel Improvement WORK ORDER NO: 79728 Springbrook CreekJAINL1954 LOCATION: Springbrook Creek/SW Grady to SW 16th St. SITE AREA 3.25 acres BUILDING AREA(gross): DEVELOPMENT PLANNING SUMMARY OF PROPOSAL The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service(SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed (Exhibit B), directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the culvert to the west and underneath the 1-405 bridge adjacent to the culvert Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. A. ENVIRONMENTAL IMPACT(e.g. Non-Code) COMMENTS Element of the Probable Probable More Element of the Probable Probable More Environment Minor Major Information Environment Minor Major Information Impacts Impacts Necessary Impacts Impacts Necessary Earth Housing Air Aesthetics WaterLight/Glare Plants Recreation LandrShoreline Use Utilities Animals Transportation Environmental Health Public Services Energy f HistonclCultural Natural Resources Preservation B. POLICY-RELATED COMMENTS C. CODE-RELATED COMMENTS We have reviewed this application with particular attention to those areas in which we have expertise and have identified areas of probable impact of areas where additional inforrpatio rs needed to openly assess this proposal. r � l 4i91grtature of Director or Aut iz Representative Date A- OC.'C Rev 1G93 t 1-405 Culvert/P-1 Channel Improvement Springbrook Creek (LUA-94-001,ECF,SP,SA,V,SM,CU) O. Dennison for Long Range January 17, 1994 1. Land use designation: Employment Area - Industrial and Employment Area - Office. 2. Comprehensive Plan policies: The proposal is generally consistent with the adopted policies of the Land Use Element, including those addressing specific land use designations, utilities and the environment. 3. Adjacent land uses: The only unanswered questions concern the existing house. Is it abandoned? If so, is it appropriate to leave its disposition outside the scope of the project? If not, have measures been designed to mitigate construction impacts to the occupants? 4. Critical areas: The proposal has satisfactorily addressed the relevant critical areas (wetlands and streams, seismic hazard area and 100 year floodplain). Conclusions: We support granting the Conditional Use and Variance requested in the proposal. F40A r8 1994, p '0 RFN o�y ING N Q _ P-1 METRO TREATMENT PLANT P-IEm �►.1� � GAP I S� IM - - - I J 0 I L 405 Project Construction Boundaries DD #1 R/W IM IM F - 7 r � I_ M I I I i � � I I I I IM 0 IM IM IM I I L I I I I IM _ _ I I L- —JLJ F -1 I I ' L - - -J � s SW 16th n � ' City of Renton Z ® r -J B❑EING CUSTOMER I I SERVICE TRAINING ® I I L — CENTER L. _ _ J LEGEND Z❑NING ®COMMERCIAL OFFICE CITY OF RENTON L — J FJM7 INDUSTRIAL - MEDIUM DRPA.RTMZZ-rr OF pvsX�Ic WORKS ® P-I PUBLIC USE NEIGHBORHOOD MAP P-1 CHANNEL IMPROVEMENTS STA 670+76 TO 680+26.37 Mamma OAT& 12/93 nt WAM DRA* MDO DKDiaa tour 1'=200' ras soon MD MvwoN Er ArM, DATE AIMpvM rQri ro1•sAWIT rs BR/OCE \ 41F£7RO RO' 1 MEA/A W PLAN r Q aA41E'OAM \ 1 o-If'W n / t-lu s' / RES FERN \ \ yy a Ar. iEYo•/>i 7 7 ' cpvs+Arcnar rrn.ao�• / '� AOIR wrs Art/l•M - + /Or OA w" /�S/IMv/llCn3r MA A4Lf arf.1[O.Ai��.ra Af grup / � f S[r SIRr1 D.O. /1 r.i or AV/10 cr'MI Aron Bae�Nc rAz (La\cAov£sJ vmI 1 ■, mare Erwaur ' If ::::::::.:..:ii!ii :::••!ik!�'!iiiiii:j:a' � .�!� y• 1�V 1 / 'AL' ?flr�ii;!I i :;!!i;jilii.iii!fi!il!11•::! ./ .�' / s \ o ::is ...:......a..0....:•.: ::::::. A[s RIYSAIA•(�1K'/IIr AlA( :'f!iif;i!i:o::::f:::::�• :: \�, � 1 ^ S K o ::::::: ........... ......... ...... h a r a7v ::: ^:•::�• ;:1' � �� REST /' \ b MR �A�r dlOor :!• �iiiiii'i '• iE`jiiEiiiE: jt O^ �� \ y1 ry !k i iiii Fi.": iiii:E i!iiiie.. •�' 1 / E � 'r'0i!^:.'.r.:a::.iii.ffff°i ii••:•r.::::::::: t' , ,��'�' \ 1 aA°.arcarilaxwrPAnlrcr i!E!f!!:..liif::::i::�l!:•Ei'�!!liii':.'.i!:!!!EE 'r '� 1 b b V .......... ;iii _ O d lf::: BC>fWY+ � rE`IEE .....iAii�'� lit � � :n.r Arrrwe Awr POW*Par }I RIEN �� '' sA .ar Aron or err 1 1 A tI "ra 6ROUP rax.rwr MEAL 1N b [Arsn.1c arrr.wr 1 I I IdG®ID Cr I e'oar.l.cncw Aor rrr rAOOrr p r^�1••��� 1 I n°+ S _ L1rS/l1t/O'ACArO tuJT R1MQ/K W A.ktl,SOII�wI 1 I ✓,iw,a wl� I I 1 — anrmr Low.. O�AAIfI SE A I — e — riM snr[r,�.i I Arorry Awr I I I ______ awla l..c/w nor M wl L"TIv Ord1'4rA .W.14AII Patr mrsm(cam— PLAN nm IAo•wlrw rAAw q I A[l Al/AMC-a ESCJP-J 39 r o n.nnc ACrA—V W ..1.1 i �8e 1 1 •�! 1 1 �RLa� Q LLJ 14. 1 r: ::::::::::::::.:::::::::::::::......:.:tee:?: .................................. S.W. 16 TN ST. _...� .::: Z� ................................................... . .... 8$ a �: ; 1 ; ....... 2 a 1 7 '-�_ '- 3 � t ' y i 5..R. 405 a -- L 1 m •\ 8 WIN! MiUlp ��Al i_ ERR N GRADING PLAN i P-I CHANNEL SrA. 670+76 rO 680+26..J7 urr mr wur r.o � � 1 4 es rwwcqu °"- U.S DEPARTIAUM OF AGRICULTURE SCIL CONSERVATION SERVICE co C JA oil, ...3ii 1 _ ---T Siiei l _- ............ SO, ars A @q _ � 1 TREE CUMWG/LAND CLEARING PLAN P-1 CHANNEL STA. 670*75 TO 680t26.J7 .r �"''•'" °°g" .w yar "� li arr AM amr�10 L mwn rawt 'w'a rw_ U.S. DEPARTMENT OF AGRICULTURE SOM CONSERVATION SERVICE i Mlk owl at � p� 'a','i , a i s i a _ .....,, ii#f #� f t a ! ! i# i # t ieNil �� t, a UN Milli t # WI 0 0V tR AF y g•00 \ \ C •QO \ \ •O••O •OO n •OHO i 00 lilt ag o � ApY WA Y� O a �-T a a REHAB/UTA770N/L4NDSCAPE PLAN n LLM —o" # P-1 CHANNEL STA. 670•r 76 IO 680+16.-J7 4 +'s mwry U.S. DEPAMMENT OF AGRICULTURE SOII. CONSERVATION SERVICE SW GRAD Y WA Y BOX CUL VE R T PROPER T Y L/NES ROAD CCNTERL/NE / /_7 \ OAKESDALE AVE SW RETAIN/NG WALL O � 1 \ 1-405 BOX CULVERT /-405 BRIDGE BRIDGE ABUTMENT AND SUPPORT PIL/NG WETLAND A -- _ OAKESDALE AVE SW \ \ \ RETAINING WALL APPROXIMA TE TOP APPROX. TOP OF BAN\ , Qj \ \ OF BANK � o SINGLE FAMIL Y RESIDENCE APPROX. ORDINARY \ SW 16 TH S T HIGH WATER MARK l \ \, BRIDGE (APPROX.. AVE DEPTH 2-4 FTC �� I 5 w 16 n+5T DIREC7701V OF FLOW —REIdld!/11r`-ice FOR SPRINGBROOK RETAINING WALL :a CREEK 0 PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING- AT: SPRINGBROOK CREEK (RM 0.5 TO H BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: EXISTING CONDITIONS PLAN COUNTY OF: KING ADJACENT PROPERTY OWNERS: STATE OF: WASHINGTON 1. KING COUNTY DRAINAGE DIST. NO. 1 DRAWN BY: MOD APPLICATION BY: CITY OF RENTON o 2. PUGET WESTERN, INC. ? 3. CITY OF RENTON SHEET: / OFZ 4. GROUP HEALTH COOPERTIVE 0 1"-120 120 DATE: 3-15-94 5_ BOEING COMPANY 6. WASHINGTON DEPT. OF TRANSPORTATION 2 7. MUNICIPALITY OF METROPOLITAN SEATTL ( IN FEET ) tD 0 rn m WING WALL _ �� j20L LNDENED CHANNEL o t"-1 20' 120 - ( IN FEET ) 1Vr 50" /-405 BOX CUL IiERT OUTLET CHANNEL 90" STREAM _ CEALZERLWE -OW FLOW CHANNEL BANK IMPROVEMENT CENTERVNE-HIGH FLOW CHANNEL 20' CONC. WINGWALL .1 — 1- ' 40' CONC. WINGWALL \ APPROX TRAIL ALIGNMENT — l`1-405 BOX CUL VtRT INLET CHANNEL EXIS77NG CHANNEL TO REMAIN LEGEND. DZZC NEW CUT/F?LL SLOPE PEDESTRIAN TRAIL .wi5 rr 9A,* 80' GAB/ON WALL u 11N9 YAS 3 Al 16N MEN W WIDENED CHANNEL NEW PEDESDB "'syCFCYE :............ A/L ACCESS GYJPR70Q'e _ :::::::::: I . ALIOVA45VT MEl2iiidiE:fEEi5E3F..... 7RAN91WrA77aV GVW-TCW .. ANS/POW-GNANNEL ti PURPOSE: INCREASE FLOOD CONVEYANCE PROJECT TITLE: 1-405 BOX CULVERT IN: CITY OF RENTON AND STORAGE, REPAIR UNDERCUT STREAM P1 CHANNEL IMPROVEMENT (SPRING— AT: SPRINGBROOK CREEK (RM 0.5 TO BANK, MINIMIZE EROSION POTENTIAL. BROOK CREEK) 0.7) ® 1-405 CROSSING DATUM: 1929 NGVD SHEET TITLE: PROPOSED CHANNEL AND COUNTY OF: KING ADJACENT PROPERTY OWNERS: PEDESTRIAN TRAIL PLAN STATE OF: WASHINGTON SEE SHEET f OF Z APPLICATION BY: CITY OF RENTON o SHEET] 2-OF L DRAWN BY: MD0 DATE: 3-15-94 :s SCALE: AS NOTED • 2 ' W c CITY OF RENTON MEMORANDUM Date: March 15, 1994 To: Ron Straka, Surface Water Utility From: Lenora Blauman ':;e Subject: 1-405 Culvert/P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU This memo is to inform you that the environmental review comment and appeal periods have ended for the Determination of Non-Significance - Mitigated for the above-referenced project. Since no appeals were filed, this decision is final. The date of Tuesday, April 5, 1994, at 9:00 a.m., has been set for a public hearing to review the land use permit application. The hearing, before Mr. Fred Kaufman, Renton Hearing Examiner, will be held in the Municipal Court Building, adjacent to City Hall, Renton, Washington. The applicant, in this case the City, is required to be represented at the public hearing. Scott Woodbury and you should attend. A copy of the Preliminary Report to the Hearing Examiner will be made available to you one week before the hearing. Please contact Georgia Shives, ext. 5582, or Sandi Seeger, ext. 5581, regarding picking up or receiving the staff report. If you have any questions I can answer, please call me at ext. 6181. Thanks. HO(MEMO.DOC CITY OF RENTON MEMORANDUM Date: February 24, 1994 To: Ron Straka, Surface Water Utility From: Lenora Blauman Subject: 1-405 Box Culvert/ P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU The comment period for this project has ended. The required 14 day appeal period will end at 5:00 p.m. on March 14, 1994. Appeal procedures and the mitigation measures imposed by the City of Renton's Environmental Review Committee are available at the Development Services Division, Third Floor. If you have any questions or desire clarification of the above, please call me at extension 6168. Thanks for your hard work! CC: Scott Woodbury dnsmmm CITY OF RENTON MEMORANDUM Date: February 3, 1994 To: Ron Straka, Surface Water Utility From: Lenora Blauman �/�� Subject: 1-405 Box Culvert/ P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU On behalf of the Environmental Review Committee, I would like to inform you that they have completed their review of your project. The Committee, on February 2, 1994, decided that the above-referenced project will be issued a Determination of Non-Significance-Mitigated. See enclosed Mitigation Measures document. The City of Renton Environmental Review Committee has determined that it 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). Conditions were imposed as mitigation measures by the Environmental Review Committee under their authority of Section 4-6-6 Renton Municipal Code. These conditions are necessary to mitigate environmental impacts identified during the environmental review process. The 15 day comment period for this project will end on February 22, 1994. Following the end of the comment period, the City will finalize its Determination unless comments received require a reevaluation. Following the finalization of the Determination, there is a required 14 day appeal period of which you will be notified. Appeal procedures and the mitigation measures imposed by the City of Renton's Environmental Review Committee are available at the Development Services Division, Third Floor. You should be prepared to make specific factual objections. If you have any questions or desire clarification of the above, please call me at extension 6168. Thanks for your hard work! CC: Scott Woodbury dnsmmm DETERMINATION OF NON-SIGNIFICANCE-MITIGATED MITIGATION MEASURES APPLICATION NO(S): LUA-94-001,ECF,SP,SA,V,SM,CU APPLICANT: City of Renton, Surface Water Utility PROJECT NAME: 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) DESCRIPTION OF PROPOSAL: The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. LOCATION OF PROPOSAL: Springbrook Creek/SW Grady to SW 16th St. MITIGATION MEASURES: The Environmental Review Committee issued a Determination of Non- Significance - Mitigated with the following Mitigation Measures: 1. To address construction impacts of the proposed project on the natural and built environment, the applicant shall submit a construction mitigation plan for approval of the City and SCS. 2. To minimize the potential impact of temporarily routing Springbrook Creek to bypass the work area and implementing dewatering operations while construction is in progress within the existing stream channel, the applicant shall submit a bypass plan and dewatering plan for approval. 3. To address construction impacts of the proposed project on the natural and built environment, the time and extent of disturbance within the channel shall be kept to a minimum. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design, such as seeding, plantings, rip rap, and erosion control blankets. 4. To minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to the period between June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. 5. In order to determine if pollutants that may be in sediments to be removed during the project are below levels requiring special disposal and/or if additional sediment testing is required, the applicant shall submit a sediment monitoring report to the City and SCS for review. 6. To minimize potential impact to cultural resources that may be present in the project area, the individuals involved with construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City, and the Washington State Historic Preservation Officer to determine the course of action. Advisory Notes to Applicant: The following notes are supplemental information provided in conjunction with the environmental determination. Because these notes are provided as information only,they are not subject to the appeal process for environmental determinations. 1. In accordance with standard contract requirements, normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. The construction mitigation plan should include advance notification and other provisions as needed to minimize the impact of construction on the occupants of the existing house adjacent to and west of the project area. 2. To minimize the potential for impact to existing structures, the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. 3. The mitigation measures included in this determination were proposed by the applicant in the project application documents. It is the responsibility of the applicant to ensure that all mitigation is implemented as proposed, and that any additional information requiring review is submitted and approved prior to construction. mitmeas - 1 - 02/03/94 CITY OF RENTON Planning/Building/Public Works Department Earl Clymer, Mayor February 3, 1994 Mr. Jim Douma Group Health Cooperative 521 Wall Street Seattle, WA 98121 SUBJECT: 1-405 Culvert/ P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU Dear Mr. Douma: On behalf of the Environmental Review Committee, I would like to inform you, as a party of record, that they have completed their review of the above-referenced project. The Committee, on February 2, 1994, decided that the above- referenced project will be issued a Determination of Non-Significance-Mitigated. See enclosed Mitigation Measures document. The City of Renton Environmental Review Committee has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21 C.030(2)(c). Conditions were imposed as mitigation measures by the Environmental Review Committee under their authority of Section 4-6-6 Renton Municipal Code. These conditions are necessary to mitigate environmental impacts identified during the environmental review process. The 15 day comment period for this project will end on February 22, 1994. Following the end of the comment period, the City will finalize its Determination unless comments received require a reevaluation. Following the finalization of the Determination, there is a required 14 day appeal period of which you will be notified. Appeal procedures and the mitigation measures imposed by the City of Renton's Environmental Review Committee are available at the Development Services Division, Third Floor. You should be prepared to make specific factual objections. If you have any questions or desire clarification of the above, please call me at 277-6168. For the Environmental Review Committee, i Lenora Blauman j Project Manager cc: Scott Woodbury, Surface Water Utility Ron Straka, Surface Water Utility PORLTR.DOC 200 Mill Avenue South - Renton, Washington 98055 THIS PAPER CONTAINS 5W�RECYCLED MATERIAL,IO fi POST CONSUMER CITY OF RENTON MEMORANDUM Date: January 7, 1994 To: Ron Straka, Surface Water Utility From: Lenora Blauman �� Subject: 1-405 Culvert / P-1 Channel Improvement (Springbrook Creek) LUA-94-001,ECF,SP,SA,V,SM,CU The Development Planning Section of the City of Renton has received the above-referenced application for environmental review. I have tentatively scheduled a presentation of the project to the ERC Committee on February 2, 1994. At that meeting, I will work with you and your team to present staff recommendations for the Committee's review and environmental determination. Following the ERC meeting, I will send you copies of the determination along with the timeframes for the public comment and appeal periods for your files. ACPTMEMO.DOC AFFIDAVIT OF PUBLICATION k:aren Ti-ic •cer being first duly sworn on oath states that he/she is the Legal Clerk of the VALLEY DAILY NEWS 600 S. Washington Kent, WA. 98032 NOTICE OF APPLICATION a daily newspaper published six (6) times week. Said newspaper Is a legal FOR SHORELINE SUBSTANTIAL newspaper of general circulation and is now and has been for more than six DEVELOPMENT PERMIT months prior to the date of publication referred to, printed and published in the Notice is hereby given that: The city n P Renton Surface Water Utility has filed an English language continually as a daily newspaper in Kent, King County, Wash- application for a substantial development • ington. The Valley Daily News has been approved as a legal newspaper by order permit for the construction or development of the Superior Court of the State of Washington for King County. Tne Springbrook Cre Channel I Gramprovement Project — SW Grady Way to The notice in the exact form attached, was published in the Valley Daily News SW 16th Street. The project is linear in (and not in supplement form) which was regularly distributed to the subscribers shape and is adjacent to, and includes por- during the below stated period. The annexed notice, a tlons of, a reach of Springbrook Creek that Not i o f A p p l i at i n f r S h r_r e l i n e S Lt kJ— flows to the north. The project is generally bounded by SW 16th Street on the south, SW Grady Way on the north, and the 1-405 Stant i'al Development Permit Oakesdale Avenue SW underpass on the east. The proposed channel will be con- structed by removing the fill adjacent to the 1-7-94 & 1—14-94 existing channel which blocks the existing was published on I-405 box culvert, and bring the box culvert into service as originally intended by allow- ing flows to pass through it. The existing The full amount of the fee charged for said foregoing publication is the sum of channel would be preserved to convey 99. 7t j some flows in larger storm events, provide $ needed flood storage,and create off-stream habitat for fish and wildlife use. The project 5 will also provide for a trail link across the 1-405 corridor along the west bank of the Legal Clerk, Valley Daily News existing channel. The project is located within Sections(s) 24 of Township 23 N, Range 4E,W.M.,in the City of Renton,King ':ith January 94 County, Washington. Said development is Subscribed and sworn before me this day qf 19 proposed to be within Springbrook Creek, and/or its associated wetlands. Any person desiring to express his views Q- r P or to be notified of the action taken on this application should notify the City of Renton Development Services Division, Renton Notary Public or the State of Washington Municipal Building, 200 Mill Avenue S.Ren- ton, Washington 98055 in writing of his residing at Auburn interest within thirty (30) days of the last King County, Washington publications of this notice. Publication dates of this notice are 1/7/94 and 1/14/94. Published in the Valley Daily News Janu- VDN#1164 Revised 7/92 ary 7 and 14, 1994. 9809 w City of Renton STAFF Department of Planning/Building/Public Works REPORT ENVIRONMENTAL REVIEW COMMITTEE A. BACKGROUND ERC MEETING DATE February 2, 1994 Project Name 1-405 Box Culvert/P-1 Channel Improvement (Springbrook Creek) Applicant City of Renton Surface Water Utility File Number LUA-094-001,SA,ECF,SP,V,SM,CU Project Manager Woodbury 5547, Blauman 6168 Project Description The purpose of this proposed project is to complete the construction of P-1 Channel improvements from SW Grady Way to SW 16th Street. The proposed project is the final segment of a series of flood control improvements to the Springbrook/P-1 Channel made from 1984 to 1990 with the assistance of the United States Department of Agriculture Soil Conservation Service (SCS). The existing Springbrook Creek stream channel, which conveys drainage from a 22 square mile watershed, directs flows north under the SW 16th Street bridge toward the 1-405 box culvert. However, since the corresponding channel improvements to direct flow into the box culvert were not constructed, fill now blocking the 1-405 box culvert forces the flow around the box culvert to the west and underneath the 1-405 bridge adjacent to the box culvert. Construction of these improvements is planned now to improve the functioning of the channel. A pedestrian trail will also be established pursuant to the City's Master Trails Plan. Project Location Springbrook Creek/SW Grady Way to SW 16th Street Exist. Bldg. Area gsf N/A Proposed New Bldg. Area gsf N/A Site Area 3.25 acres Total Building Area gsf N/A RECOMMENDATION Staff Recommend that the Environmental Review Committee issue a Determination of Non- Sign ificance-M itigated. Project Location Map ERCRPT.DOC City of Renton P/B/PW Department Environmental Review Committee Staff Report 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001,SA,ECF,SP,V,SM,CU REPORT AND DECISION OF FEBRUARY 2, 1994 Page2 of 5 B. RECOMMENDATION Based on analysis of probable impacts from the proposal, staff recommend that the Responsible Officials make the following'Environmental Determination: DETERMINATION OF DETERMINATION OF NON-SIGNIFICANCE NON-SIGNIFICANCE-MITIGATED. Issue DNS with 14 day Appeal Period. Issue DNS-M with 15 day Comment Period with Concurrent 14 day Appeal Period. Issue DNS with 15 day Comment Period with Issue DNS-M with 15 day Comment Period Concurrent 14 day Appeal Period. X followed by a 14 day Appeal Period. C. MITIGATION MEASURES 1. To address construction impacts of the proposed project on the natural and built environment, the applicant shall submit a construction mitigation plan for approval of the City and SCS. 2. To minimize the potential impact of temporarily routing Springbrook Creek to bypass the work area and implementing dewatering operations while construction is in progress within the existing stream channel, the applicant shall submit a bypass plan and dewatering plan for approval. 3. To address construction impacts of the proposed project on the natural and built environment, the time and extent of disturbance within the channel shall be kept to a minimum. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design, such as seeding, plantings, rip rap, and erosion control blankets. 4. To minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to the period between June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. 5. In order to determine if pollutants that may be in sediments to be removed during the project are below levels requiring special disposal and/or if additional sediment testing is required, the applicant shall submit a sediment monitoring report to the City and SCS for review. 6. To minimize potential impact to cultural resources that may be present in the project area, the individuals involved with construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City, and the Washington State Historic Preservation Officer to determine the course of action. Advisory Notes to Applicant: The following notes are supplemental information provided in conjunction with the environmental determination. Because these note are provided as information only, they are not subject to the appeal process for environmental determinations. 1. In accordance with standard contract requirements, normal working hours will be between 7:00 a.m. and 6:00 p.m., Monday through Friday. Permission to work other hours and times must be obtained from the City and may be subject to the City Noise Level Regulations and other conditions. The construction mitigation plan should include advance notification and other provisions as needed to minimize the impact of construction on the occupants of the existing house adjacent to and west of the project area. 2. To minimize the potential for impact to existing structures, the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. 3. The mitigation measures included in this determination were proposed by the applicant in the project application documents. It is the responsibility of the applicant to ensure that all mitigation is implemented as proposed, and that any additional information requiring review is submitted and approved prior to construction. ERCRPT.DOC City of Renton P/B/PW Department Environmental Review Committee Staff Report 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001,SA,ECF,SP,V,SM,CU REPORT AND DECISION OF FEBRUARY 2, 1994 Page3 of 5 D. ENVIRONMENTAL IMPACTS Whether the applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with the proposed development? 1. Earth Impacts: Soil erosion could occur in connection with the construction of the proposed project, since the entire area of channel and pedestrian trail construction will be temporarily cleared of existing vegetation. Erosion could occur during rain and/or wind storms that occur during the construction phase of the project. To minimize this potential for soil erosion, site preparation techniques and best management practices will be designed in advance of and implemented throughout construction. The project design includes a combination of plantings, seeding, rip rap, and erosion control blankets to minimize the erosion potential after construction. Because of the proximity of excavation to the Municipality of Metropolitan Seattle (METRO) sewer interceptor pipeline and Washington State Department of Transportation (WSDOT) 1-405 structural improvements the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. Mitigation Measures: The applicant is required to provide a construction mitigation plan outlining the construction schedule and phasing, the hours of operation, the proposed earthwork material source/disposal site and haul route, and any measures to be implemented to minimize the impact of construction to surrounding property owners and public streets. As required by City regulations, the applicant will submit prior to construction an erosion control plan and construction sequence for City and SCS approval that addresses local, state, and federal permit requirements for minimizing the erosion potential and the potential related effects on the water quality of Springbrook Creek. In general earthwork activities should be done during period of dry weather. The disturbed area within the existing channel and other areas of the project will be kept to a minimum. To minimize the potential for impact to existing structures, the applicant and construction contractor shall coordinate with METRO and WSDOT as applicable. Shoring measures will be implemented as needed for excavation work near existing structures and the METRO interceptor pipeline, which are to be undisturbed. The time and extent of disturbance within the channel shall be kept to a minimum. As soon as definable segments of the work are determined to have been completed, or as unexpected and seasonal conditions dictate, disturbed areas are to be stabilized using the methods proposed in the project design. 2. Water Impacts: Because work areas must be sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel, Springbrook Creek will be temporarily routed to bypass the work area while construction is in progress within the existing stream channel. The bypass is anticipated to be accomplished by pumping or gravity flow through a piped conveyance or open channel, or some combination of these methods. Bypassing the surface water flow around disturbed areas will also minimize the erosion potential of the exposed soils and protect the water quality of Springbrook Creek. Ground water withdrawal for temporary dewatering purposes is anticipated to be necessary in order to maintain the work area sufficiently dry for the grading, placement, and compaction of material needed for the proposed channel. The groundwater may be rich in dissolved iron, which may be oxidized upon exposure to air and settle out of solution to produce a rust colored plume downstream of any groundwater discharge point. This will temporarily reduce the aesthetic value of the affected area which will return to original condition over time. Mitigation Measures: The applicant will submit a bypass plan outlining the proposed sequence and timing of any surface water bypass. Any proposed surface water bypass will also be reviewed by the Washington Department of Fisheries. It is anticipated that construction of the channel north and south of 1-405 will occur in two separate phases so that the bypass distance will be reduced from that required to bypass the entire reach. The actual quantity of water to be bypassed depends upon the hydrometerological conditions, such as precipitation levels, at the time of construction. By working in the summer months the amount of flow to be bypassed will be minimized. The bypass plan shall include a backup system for maintaining or supplementing the function of any water bypass should the primary diversion fail or function inadequately. The bypass must be capable of handing mainstream Springbrook Creek flows of a minimum of the 2-year recurrence interval or design storm, a flow of 455 cfs (R.W. Beck, 1991). The plan is also to include an emergency monitoring and contingency plan for work within the channel. The plan will outline measures to ERCRPT.DOC • . City of Renton P/B/PW Department Environmental Review Committee Staff Report 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001,SA,ECF,SP,V,SM,CU REPORT AND DECISION OF FEBRUARY 2, 1994 Page4 of 5 implement for immediate stabilization of disturbed areas at risk to flow of water, should the bypass system 2-year design capacity be in danger of being exceeded. The applicant will submit a dewatering plan outlining the proposed dewatering extent, sequence, and timing. All ground water withdrawals are to be directed, if conditions permit, into the METRO sanitary sewer, temporary settling pond, or other device to minimize the discharge of iron rich water into Springbrook Creek. See Earth section for other mitigation measures. 3. Plants Impacts: During the construction process, the entire area of channel and pedestrian trail construction will be cleared of existing vegetation, resulting in temporary loss of the vegetative cover. Mitigation Measures: The project design includes a combination of planting and seeding that will reestablished vegetative cover removed by construction as soon as definable segments of the work are determined to have been completed. In accordance with City requirements, a maintenance bond will be posted as surety that any needed maintenance of installed improvements will be performed. 4. Animals Impacts: Salmonids have been recorded migrating upstream at the Black River Pump Station. The Department of Fisheries has also indicated that Springbrook Creek supports runs of coho salmon and other anadromous fish including steelhead, cutthroat trout and dolly varden trout. Project construction within the existing channel will require Springbrook Creek to be temporarily routed to bypass the work area while construction is in progress. This will temporarily prevent passage of fish through the channel within the project area. Any birds, mammals, and other wildlife that have been observed on or near the site or are known to be on or near the site may be temporarily displaced by construction of the project. Mitigation Measures: To minimize the impact of temporarily preventing passage of fish through the channel, construction within the existing channel will be restricted to during the summer months of the fisheries window from June 15 - September 15 as approved and in accordance with permit conditions to be established by the Washington State Department of Fisheries. Fish habitat enhancement components are included in the project design and consist of placing root wad and boulders groups in the low flow channel to create resting areas for migrating fish. Plantings along the low flow channel will provide shading for migrating fish in the low flow channel. No mitigation was proposed by the applicant for temporary displacements to other wildlife. Based on on-site observation and considering the urban surroundings of the project area, the adjacent local streets, and the 1-405 freeway, it is anticipated that wildlife use is minimal. However, to minimize any potential displacement impact, the time and extent of disturbance within the project area shall be kept to a minimum. 5. Environmental Health Impacts: Dredging or other construction disturbance as part of this project could cause contaminated sediments that may be already existing in the project reach to be suspended and carried downstream. Contaminants that may be in the dredge spoils could also be a potential health risk if not disposed of properly. Although previous sampling at SW 16th Street indicated that contaminants in the sediment at that location were below Model Toxics Control Act (MTCA) cleanup regulation levels and special disposal of the sediments would not be required, further assessment of the site is being conducted. Herrera Consultants was contracted to test a surface sample and a sample at one foot depth at a total of four locations within the project area. The field work was completed at the end of September, 1993, and a report of the results is expected in late February, 1994. The findings of the report will be used to assess additional sampling needs and disposal requirements. Mitigation Measures: The applicant shall assess the Herrera sediment monitoring report once completed to determine if the pollutants are below levels requiring special disposal and/or if additional sediment testing is required. Additional testing may be necessary depending upon the requirements for use of the dredge material disposal site agreed upon by the disposal site's owner. As noted in the Earth section, the disposal site will be identified in the construction mitigation plan. If sediment monitoring results are found to exceed MTCA levels, the applicant will obtain a permit from King County for disposal of the contaminated sediments at the Cedar Hills landfill permitted by King County. ERCRPT.DOC City of Renton P/B/PW Department Environmental Review Committee Staff Report 1-405 BOX CULVERT/P-1 CHANNEL IMPROVEMENT(SPRINGBROOK CREEK) LUA-94-001,SA,ECF,SP,V,SM,CU REPORT AND DECISION OF FEBRUARY 2, 1994 Page5 of 5 6. Historical and Cultural Preservation Impacts: It is possible that project excavation activities may unearth cultural resources, although much of the project area has been significantly disturbed by past construction for the adjacent local streets and 1-405 freeway. Mitigation Measures: The individuals involved in construction will be required to watch closely for buried artifacts and remains, and if found, cease work and provide notification to SCS, the City of Renton, and the Washington State Historic Preservation Officer to determine the course of action. 7. Transportation Impacts: The final SW 16th Street pedestrian trail crossing location and design may potentially impact public safety if unmitigated. Hauling of materials during construction could have impacts on traffic in the project vicinity. Mitigation Measures: The final SW 16th Street crossing alternative and mitigation measures to be constructed will be determined by the City Transportation Division in a planned study of the crossing alternatives. For the options considered in the proposed project documents the following measures were anticipated by the applicant: 1) provide a pedestrian traffic signal and marked crosswalk of SW 16th Street, 2) construct signage in advance of the crossing to warn motorists of its location, and 3) modify the SW 16th Street and SW Oakesdale Avenue intersection to a three way stop to eliminate the free southbound right turn from SW Oakesdale Avenue onto SW 16th Street. The applicant is required to provide a construction mitigation plan, which includes traffic control, as noted in the Earth section. 8. Utilities Impacts: A portion of the proposed channel is directly adjacent to the Oakesdale Avenue SW underpass and underdrain system. The capacity of the underdrain system, which protects the Oakesdale Avenue SW underpass from groundwater seepage onto the roadway, may be overburdened by the short circuiting of water from the proposed channel which will be located directly adjacent to the underdrain system. Mitigation Measures: To prevent piping of water from the channel through the soil and into the Oakesdale Avenue SW underdrain system, the membrane will be connected to the Oakesdale Avenue SW P-1 channel retaining wall and extended west across the width of the channel. This increases the flow path that water from the channel must travel to reach the underdrain system and will effectively reduce the potential for removal of finer particles from supporting soils due to piping and overburdening of the underdrain pump system. E. COMMENTS OF REVIEWING DEPARTMENTS The proposal has been circulated to City Departmental / Divisional Reviewers for their review. Where applicable, these comments have been incorporated into the text of this report as Mitigation Measures and/or Notes to Applicant. X Copies of all Review Comments are contained in the Official File. _ Copies of all Review Comments are attached to this report.. E RCRPT.DOC N O C❑ P-1 C❑ C❑ METRO TREATMENT PLANT P-1 P-1 vy � G I C� Cj C❑ J IM r IL �J L f� 40F Project Construction Boundaries DD #1 R/W cJ IM IM F 1 _ IM I I I I f� I I I I IM �� IM IM IM IM IM I I L L — I I L_ — J LJ SW 16th ST City of Renton Fc❑ B❑EI G CUSTOMER I I I SERVICE TRAINING c❑ I I L — CENTER � I I I I LEGEND Z❑NING C❑ C❑MMERCIAL ❑FFICE CITY OF RENTON L - J IM INDUSTRIAL - MEDIUM DEPARTMENT OF PUBLIC WORKS © P-1 PUBLIC USE NEIGHBORHOOD MAP P-1 CHANNEL IMPROVEMENTS STA 670+76 TO 680+26.37 DEBNiNED. DATE'12/93 FLE NAME DRAWN MDD OHE000. BCAL6 1"=200' ran.00a NO. REVEEON BY APPR.1 DATE APPROVED. SHEET. CLWS7RLc'nOV ��Z BR/oGE \ METRO GROUP \ TREATMENT PLANT Q CUR DATA D 14'9'70' nFr im'a �/ qq gg R-#W' �, r-eats' I I / PUCEr`. \ / WESTFR/J, neW 7Cp19Pr1C r i CtiW57ROClRN � ^� e Aaxx UM75 WEW cavfRr Ar4lrOF .:s5 CM .. A W s'MOED rRAa i �s pc Ba'cvc KRr wnma u'RtRVAWEWr EASC+IEWr / � I ,rf .. 1� �� \ Aruw rxsW.c rnvara a>�sr e.�r Ar AmAam a •S'u� V :5 OF mnrrr.+o�,wA rvw, sW.,6M s7wer I D.D. /I RA71f Or WAY Rlp/7 WAY qq 9y �; M � FASI/IC laPPtSWIfA' ■ � 6 B0£/NG F Y. (LONGACRES) { 'ynr�owncwa .Rrarrav uc iY, i O (IGET 1.. / .�' ! 1 '•nor nor aunv.¢ rrARmrw \ W OFz Tq j 0 i-Pors m"la o $r I \\ Na DYBC OETRMNEOTBALIGWNTCCESS e d IRANSoPPTAROY OIN..OV ( MA&Br CS7C BEKLCWMiNr PRO.EL'T } e �'\'�: � �I. '' I \� � U BOE/NG n EN OF casnIO RErA G WALL PVY[R PaE 1r� RENT I�-SR asRrcRrcrwAr \ .4 .- - I V D.D. fl p� I WK L � KrnK Law � H 17 157.7 z o MAIPORARY I I Cam' Cn GROUP" EASQEVr $ Lx75nNc aRias-wnr 1 I U HEALTH `� { (rmcAU I I cuvs7Rtx new woar LUBr a 31 I I I -- PE/dI.4VENr EASEMENT OR I I RRc7oem7Y Low SR.fay MGNT-WAY—J I � EY/S7bVG 90'METRO WASTE.YWAG£(A1F w CEN7ER UAT.f7.OW d/AM1E2 A SW/67N S7RLFT ! I ✓R4N7 tr wAr I I o POxeR RctE SW Ism,, I LLN7ER UN£LOW fLOW c74ANATL R/GYT CM'WAY I I I _ E MG L' AR MCH WATER Y msr cQYsmuen W coP ARY Kw WATER WAw �+ PLAN ; AEW PEAESnVW1&CK7E 7RAA p w o y AEWIL'rA"W ML eu.ao ® ESCR-J $36369 o E4S71VORfrA G44U �1s1 f CURVE DATA FOR PEDESTRIAN PATH CUR /5 ,a/R . CURD£!7 CURD£ G:I WW* A:xw zT" G:/OTIDr' G-r Ww, a jo-21,' \ �- R 1a100' R 5A00' R�IDO.CO' R-mX' R 5LAW' \ HS T IRLG; T L F20.Y L SrM' L e lrB' L 0 L.MdR,' 7-11H 7.4 I \ \ I \ F F LVARO vast ¢.\ NEW II'PAYED sw MAIL W7nz rs Ile[iYsrlrRr fe - U BO£INC " w now aurlaz R.wr r aov ur 5a" (LONGACR£S) �• W f �✓f I OPKES�/ \ o Yuew REUE5rAVAN CACWSS co r(Y£lRA/L '( \ IRA/L 8 r CSTC OC6ET CFML1"T PR0.ccr - 9oRNQWGW A 1 9AAFla MWOHNENr O {� 7hV A AEL'r AREA I\VX4A4T AAm AF AAACDVr ti I i I I 70 7AE sw/81N 57M T M SW MWr WAY WAOf aI Q arEtx AV nE SLr 7/4 MD AE 114 CF 10 SECnaV TIY 7ONN9iP TJ NAP11d RAN'r 4 EASr, W-m W Km AOLNrr. WL * E. a,Y�,�•r.�,r..,r C9 r� REN7AV.s WAW WA7ER VWTY 2 O A4U*1W WJM O CJ comer.swIT Nnaabwr (ZW)277--M47Wow J d Lw ap sm as mcpmmmr or Agar=low .�... I / ME Ca% WVAAaV SF77NW = O 1 EXGI V AMWOMMMM AAD MAR(7EWS y I I I I I OW ar SANDS� MA1W'AL 1S E5> TED 1 Ut 7NE AWgOSIL 97E AAD Mix Ra"r MU&I LEG£NO NEW LbvrcriR I I I PRO. �AAV KI A ......... aeiawu cavrcrrR I I I FW Vnna9VANr SERW=LVIL W APPROVAL caysmLenav nnar/Inr A F"MNnWS AAO MAnNW- T iLYeP' cRr oe A 7VUL Ar 4=a/B/C YAARVOSd1Cy*JOIO 7pVSJ -- AAV or UAU RU MAW'AL/S ES7M7EV M BE YA WYM L:vrnRc cwaRARr Iwcv+wArER YARR 7HE S"APCF AW NN.L RW7E WU Ar APOYf W AS PART W 7AE FANL COVS7AWYMV vDsr caysmucncw oRaRARr/ncR wAIER MAWn r A RT MAMQW9Vr PLAN AAV 1l[SE SU9Wr7W ESCR—J ar a r.a 36390 r CCN6/RMC METRO GROUP \ TREATMENT PLANT IYMWlARRNANENr EA.4A/EN I \ \ I --� Raa �1u� I I I PUGET'� \ I WESTERN ntr rmwvls r cnvsmucncw xcnANo-A- / xewrr uNns Ncw Cu KRr I R/p/F'Ll� _ .: � fX/SANG 5 GLLL ctws B0.Y pK w- (LOWLRABINGPRp^O oWIF6N a mftcw§,.;l/IYlSI tl11� \� al,.l yry gKwW CdOiCR.uYv LIP,s'w As. A® t S NEFL1m!PP IRAK ( _ '� f CI SA y BL. .:. �:::1 OF • mr n'mwLr W.law•a sw L6o,sv3Er I DO y1 I $NTON Warr cr lwA� avar a / ��I �/, ♦ oaiwe•anecwrr HOEING (L ONGACR£S) I \ 0E7NN ED'06 rr nwvmLwranav a�.va✓ ` /r/ QP� / \ 1^ M&a r csc ofwl c1°NENr PRarc .... ............ � ,y � . CITY ; ... th Of' O HOEING EXL511NC RErANtlNC WA[L NPoMPIP PIXf RENT ✓{�' ��� sR.i55—1 LY-Y \ T r^ OF... .. I. caysmucnav [w (T)v swrro 1 W rx- ?rUF ARY E sc i--c— GROUP $ �r� ensnNc cw�cwar HEAL `� } (rr C&) V 1 A[1 1REE5 l0 Bf RENOYEO CYWSlR(K'AQY / �� I 4NLFS5 NOIFA OM!W9F --- I PERVANLNr EAYYENT LIP p,BB' I I [A -- sR uu RAy/r�WAY�! I — Tsnvc so'NE7Ro wasA-sswAcc unrL' � SW.lan/SrR(E7 I I LYN)ER UNE MpI FLOW L}IANNEL A I 1�'S lBM 511PEF owr or WY I I I —_ 0 _ POMER P w r�� I __-_-- CZNIER lMlf LOw 110W LY/ANN'Z � la — EwsnNC UPQWMY WlJ/WA RF NARY PAfr GYWSFR pap QPQ'NARY mcw wA IER NARY ;•j PLAN ] ACwPfaslmaN cyan BUR pg a ACw 9CTALMUC 441 ESGR—J s RESTORATION METHODS AND DETAILS „,,. � .'�'� °Qema.wre ^e eeO O{IC66000 OOOp4 00000Oeee— •rW. > ��.� WILDLIFE HABITAT PLANTING DETAIL 3zz k k k k RESTORATION SCHEDULE e a we, N. u - i ', S&-MNAB--B(TYP) BOEING (LONGACRES) l —WSW 5�/ ! A ww PfmsmYAN/6/cKZF IRAH PEE RIP RAP DETAILS V D W ACtrSS CCRIWC p ZowcNr RJ BC ate. Mw w new ORMPis avpa�sav IRAs EY CSIC O wzo twr PFO.CCr w�ww1 • " // / 0 / S // CROSS SECTION ^ I 4 Zs Q o ..v T- o00 0000 obb mow.._. m.M�`.�wo PLAN W p, 4 x.. W A Q nsN NAmrAr mwarNr ® BANYERS DWARF M LORS PLANTING DETAIL y A m�aReNAsrAraANmvc ' .� SLOT DITCH DETAIL �p4Y PLAN M ©ex x�soa eeANY£r ®WILLOW PLANTING DETAIL EXCELSIOR BLANKET DETAILS ESGR'J QR[o RAR ARMS 38391