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HomeMy WebLinkAboutSEPA E96-0002 - CITY OF TUKWILA / PUBLIC WORKS - FOSTORIA STORMWATER QUALITY MANAGEMENT PLANFOSTORIA WATER QUALITY MANAGEMENT PLAN COMPREHENSIVE STORMWATER PLAN FOR FOSTORIA BASIN SOUTHGATE CREEK BASIN - INTERURBAN AVE. S. & GREEN RIVER E96-0002 AFFIDAVIT I, �Ldl MCN \..U- _n• J Notice of Public Hearing O Notice of Public Meeting LI Board of Adjustment Agenda Packet 0 Board of Appeals Agenda Packet OPlanning Commission Agenda Packet Li Short Subdivision Agenda Packet LI Notice of Application for Shoreline Management Permit LJShoreline Management Permit OF DISTRIBUTION hereby declare that: )(Determination of Non- significance 0 Mitigated Determination of Nonsignificance Determination of Significance and Scoping Notice LI Notice of Action ri Official Notice Other 0 Other was mailed to each of the following addresses" on .AFRI L 1 , 9/0 . bail" D Cot.olLA tN1NI l Qpt A 6nr.A- 1. J� i Eve Gil o r lP o bL M P IA , q 8504 -1703 Cml n E— L.,A- Pu- 13L t ti)DRY-S PIE/PT • (vim�- �' )to I—LA ILA) WA 9 t I $g Name of Project ORIA WN - 2- lytLLALI' Signature c. AfICM li ��1 - docs P�>s File Number Z • AFFIDAVIT O Notice of Public O Notice of Public OBoard of Packet f Board of Packet ❑ Planning Packet Hearing Meeting Adjustment Agenda Appeals Agenda Commission Agenda 0 Short Subdivision Agenda Packet OF DISTRIBUTION hereby declare that: LJ Notice of Application for Shoreline Management Permit 0 Shoreline Management Permit \)i(1 Determination of Non- significance O Mitigated Determination of Nonsignificance IJDetermination of Significance and Scoping Notice ONotice of Action Official Notice Other Other was mc=3.Eff to each of the following addresses on /\PRI L 8', cl . i-11•1bR Qki_ep �EA-1TL� TMS IA L94- 2 -g<62 - Name of ProjectfV21� 1AINTER RUIN `� Signatur Q File Number el' -0002_ CHECKLIST: ENVIRONMENTAL REVIEW/SHORELINE PERMIT MAILINGS FEDERAL AGENCIES ( )U.S. ARMY CORPS OF ENGINEERS ( )FEDERAL HIGHWAY ADMINISTRATION ( )DEPT. OF INTERIOR -FISH & WILDLIFE SERVICE ( )U.S. ENVIRONMENTAL PROTECTION AGENCY ( )U.S. DEPARTMENT OF H.U.D. (REGION X) WASHINGTON'STATE AGENCIES ( )OFFICE OF ARCHAEOLOGY ( )TRANSPORTATION DEPARTMENT ( )DEPT. OF NATURAL RESOURCES ( )OFFICE OF THE GOVERNOR ( )DEPT. OF COMMUNITY DEVELOPMENT ( )DEPT. OF FISHERIES ( )K.C. PLANNING & COMMUNITY DEV. ( )BOUNDARY REVIEW BOARD ( )FIRE DISTRICT #11 ( )FIRE DISTRICT #2 ( )SOUTH CENTRAL SCHOOL DISTRICT ( )TUKWILA LIBRARIES ( )RENTON LIBRARY ( )KENT LIBRARY ( )CITY OF SEATTLE LIBRARY ( ( ( ) US WEST )SEATTLE CITY LIGHT )WASHINGTON NATURAL GAS )WATER DISTRICT #75 )SEATTLE WATER DEPARTMENT )GROUP W CABLE' )OLYMPIA PIPELINE ( )KENT PLANNING DEPARTMENT ( )TUKWILA CITY DEPARTMENTS: ( }PUBLIC WORKS ( ) FIRE ( )POLICE ( )FINANCE ( )PLANNING ( )BUILDING ( )PARKS AND ORECREATION ( )TUKWILA MAYOR )DEPARTMENT OF SOCIAL & HEALTH SERVICES )DEPT. OF ECOLOGY, SHORELANDS DIVISION )DEPT. OF ECOLOGY, SEPA DIVISION* )DEPARTMENT OF WILDLIFE )OFFICE OF ATTORNEY GENERAL *SEND CHECKLIST WITH DETERMINATIONS AND *SEND SITE MAPS WITH DECISION KING COUNTY. AGENCIES ( )KING COUNTY DEPT. OF PARKS ( )HEALTH DEPARTMENT ( )PORT OF SEATTLE ( )BUILDING & LAND DEV. DIV.- SEPA INFORMATION CENTER SCHOOLS/LIBRARIES ( )HIGHLINE SCHOOL DISTRICT ( )KING COUNTY PUBLIC LIBRARY ( )SEATTLE MUNICIPAL REFERENCE LIBRARY ( )SEATTLE SCHOOL`DISTRICTS - ( )RENTON SCHOOL DISTRICT UTILITIES ( ( ( ( ( ( ( )PUGET SOUND POWER & LIGHT )VAL-VUE SEWER DISTRICT )WATER DISTRICT #20 )WATER DISTRICT#125 )CITY OF RENTON PUBLIC WORKS: )RAINIER 'VISTA )SKYWAY CITY AGENCIES ( )RENTON PLANNING DEPARTMENT ( )CITY.OF SEA -TAC ( )CITY OF SEATTLE ( )CITY OF BURIEN ( )TUKWILA PLANNING COMMISSION MEMBERS ( ).TUKWILA CITY COUNCIL MEMBERS OTHER LOCAL AGENCIES ( )PUGET SOUND REGIONAL COUNCIL ( )P.S. AIR POLLUTION CONTROL AGENCY ( )SW K.COUNTY CHAMBER OF COMMERCE ( )MUCKLESHOOT INDIAN TRIBE ( )DUWAMISH INDIAN TRIBE MEDIA ( )DAILY JOURNAL OF.COMMERCE ( )VALLEY DAILY NEWS ( )METRO ENVIRONMENTAL PLANNING DIV. OFFICE/INDUSTRIAL 5,000 GSF.OR MORE RESIDENTIAL 50 UNITS OR MORE RETAIL 30,000 GSF OR MORE ( ) HIGHLINE TIMES ( )SEATTLE TIMES PUBLIC NOTICE MAILINGS FOR PERMITS SEPA MAILINGS Mail to: (comment period starts on date of mailing) Dept. of Ecology Environmental Review Section Applicant Other agencies as necessary (checked off on attached list) Include these documents: SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS). SEPA Checklist (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Affidavit of Dlstribution (notice was mailed & sent to newspaper). SHORELINE MAILINGS Notice of Application: Notice of application for a substantial development Permit must be mailed to owners and to property owners within 300 feet of subject property, prepare an affidavit of publication, and publish two consecutive weeks with deadline for comments due 30 days after last newspaper publication date. Shoreline Permit: Mail to: (within 8 days of decision; 30 -day appeal period begins date received by DOE) Department of .Ecology:Shorelands Section State Attorney General Applicant Indian Tribes Other agencies, as necessary (checked off on attached list). Include these documents: Shoreline Substantial Development Permit (3 -part form from Sierra) Findings (staff report, if applicable) Shoreline Application Form (filled out by applicant) Drawings/Plans of project (site plan, elevations, etc. from PMT's) Site plan, with mean high water mark & improvements _ Cross-sections of site w/structures & shoreline Grading plan Vicinity map SEPA Determination (3 -part form from Sierra) Findings (staff report, usu. with MDNS) SEPA Checklist (filled out by applicant) Any background studies related to impacts on shoreline Notice of 'Application Affidavit of Distribution (notice was mailed & sent to newspaper) Affidavit of Publication (notice was published in newspaper). C.1lY OF TUKWILA DEIERNINATION OF NON s1ON1FICAN (DNS) DESCRIPTION OF PROPOSAL: COMPREHENSIVE 'STOPMWA1•EP PLAN FOR FO'STORIA BASIN. PROPONENT: CITY OF TUKWILA - PUBLIC' WORt. S LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS. IF ANY: ADDRESS: PARCEL NO: SEC/TWN/RNG: FOSTORIA BASIN OF THE CITY OF TUKWILA LEAD AGENCY: Y: t_ ITY OF TUKWILA FILE Nt): E96-0002 The City has determined that the proposal does not have a probable significant adverse impact on Ctre environment. An environmental impact statement (EIS) is not required under RCW 43.21c.1130(2) (c) . This decision was made after review of a completed environmental checkl ist and other information on file with the lead agency. this information is avai lable to the public on request:. 1.*4s4*1.::•*:i;i•*•*•**Jb.*•***k:t•*3*;4•*:L•*:**:i*•*•**:i*b*•*-,i****:*4.44*44*4}•*•*•k*•*•*•F•*•*•**•*•*•*•*•*•*;i* • 441 chis determination is final and signed this --- day of 41.- 1991e. Steve Lancaster, Responsible Official City of Tukwila, (206) 431-3680 6300 Southcenter Boulevard Tukwila, WA 98188 You ma4, appeal this determination to the City Clerk at City Hall. 6200 Southcenter Boulevard, Tukwila, WA 98188 no later than 10 days from the above signature dat:e by written appeal stating the basis of the appeal for specific factual objections. You may be required t:o bear some of the expenses for an appeal. Conies of the procedures for SEPA appeals are available with the City Clerk and Department of Community Development. • City of Tukwila 1 John W. Rants, Mayor Department of Community Development Steve Lancaster, Director Memo to the File April 5, 1996 FOSTORIA WATER QUALITY MANAGEMENT PLAN SEPA File Number: E96-0002 The City of Tukwila's Department of Public Works proposes to develop a management plan for the Fostoria Water Basin. Separate environmental reviews will be conducted for each Capital Improvement Projects (CIP) as part of the usual plan, specification, and estimate process. Therefore, this SEPA will be administered as a Planned Action. The proposed project was routed and reviewed between February 6 and March 11, 1996. Following is a list of comments brought forth by the various city departments and individual staff Comments address the proposed plan overall; specific comments will be addressed on a project by project basis. The proposed plan would be implemented over a five (5) to ten (10) year period.. Comments from Phil Fraser, Senior Engineer: • Construct a permanent flow tote station at Southgate creek where it intersects with East Marginal Way South and 133rd Street to provide additional equipment for continuous water sampling and base flow monitoring at this station. • Monitor base flow at outfall located at 42nd Avenue South/Interurban Avenue South to determine impacts of applying the recommended BMPs and capital improvements to the basin. • Monitor basin water quality • Monitor closer compliance with Draft Surface Water Ordinance • Pursue additional coordination with the Val Vue Sewer District to help uncover risk areas through as -built plans and TV reports. • Pat Brodin, Senior Engineer confirmed that nearby septic systems known to be in operation are east of Military Road, in the vicinity of S. 135th Street. Observations by City staff and Val Vue personnel confirmed evidence of soap suds during major rain storm events. 6300 Southcenter BoulevarcL Suite #100 • Tukwila, Washington 98188 • (206) 431-3670 • Fax (206) 431-3665 • • Memo to the File, page 2 FOSTORIA BASIN MANAGEMENT PLAN SEPA File # E96-0002 • Coordinate with upper watershed jurisdictions to allow improvements outside the City's boundaries. Comments from Gary Shulz, Urban Environmentalist: • Show how water quality features proposed in overall plan will improve water quality in the creek. It was suggested that modifications be made outside the natural drainage area in order to attain less sensitive area conflicts. • Explain how water quality features will improve a potential fisheries/fish restoration element, specifically showing how it is connected to the proposed CIP project and overall . plan. • Prioritize proposed CIP projects to promote upper watershed improvements. This would enable there to be a monitoring program for the upper watershed area and determine if in - stream and lower watershed projects are appropriate. • Recommendations were made for a regional detention facility since small detention facilities may not meet long term goals of improving water quality and reducing erosion with in the City. • Specifically address: North Fork Southgate - install detention at upper end of drainage and monitor for channel improvements. Middle Fork Southgate - considerable amount of undeveloped land is still present at the upper portion of the fork, just east of Pacific Highway. Some of the area is relatively flat and could be considered for developing small ponds; pond does not appear to be receiving large runoff flows. South Fork Southgate - Consider a Driscoll pipe connection to the bottom of the ravine, and possibly a sediment vault at the ravine bottom. The inlet to Southgate creek is eroding rapidly and contributing a large amount of sediment to the system. Most runoff is received from a large pipe under Pacific Highway. Southgate Creek (downstream of Middle and North Forks) - Altering this area could change the rate of flow to the downstream system. Therefore, a drainage improvement to the creek (through the "horse pasture") would likely require an easement or acquisition. It would be recommended to reroute or create a new channel within the right-of-way of 133rd and 131st Avenue South, which could also become a fish enhancement area. Memo to the File, page 3 FOSTORIA BASIN MANAGEMENT PLAN SEPA File # E96-0002 Comments from Don Williams, Parks and Recreation Department: • Clarify ownership of Pond #1 as Tukwila Parks and Recreation (turned over to them by King County Parks in 1992). The site was purchased under Forward Thrust Bond funds which specifically states that property can only be used for parks and recreation purposes, not as a stormwater retention pond. Therefore, the report must outline a mitigation strategy to change the use on the site. Clarification of ownership will also be necessary for notification purposes and to obtain property owner approvals. • Address impact of the proposed project on salmon and other wildlife, specifically areas of the proposal that address construction projects. Agencies from whom individual approval will be needed should be listed in the proposal. The revisions listed above were made and incorporated into the Fostoria Basin Stormwater Quality Management Plan, dated March 1996. The revised plan is proposed to proceed in phases over a five (5) to ten (10) year period. CIP projects # 10, 12, 13, 14, 8, 3, 16, 11 a, 11b (listed in order of priority) have been recommended to be addressed first in the plan. MEMORANDUM TO: Phil Fraser, Senior Engineer FROM: Gary Schulz, Urban Environmentalist - DCD DATE: March 1, 1996 RE: Fostoria Stormwater Quality Plan. RECEBVED MAR 0 4 1996 DEVELOPMENT My comments for the January 1996 draft management plan are provided below. I appreciate the revisions that may have considered my November 16, 1995 Memo. Therefore, I am just submitting general comments to possibly incorporate into the plans management strategies and policies. Some of these ideas may already be included in the management sections of the plan. 1) Coordination with upper watershed jurisdictions may eventually allow improvements outside the City's boundaries but could have beneficial affects to Tukwila. 2) The fishery element or restoration of fish use does not seem connected to the proposed CIP projects and overall plan. However, it is assumed that water quality improvements will enhance a potential fishery. Will "water quality features" (page 43) improve a potential fishery? 3) Will "water quality features" improve water quality in the Creek? Many of the CIP projects will certainly improve the discharges to the Duwamish River. However, some may have not major influence within the Creek. It is not clear whether the plan should emphasize water quantity - storm flows, sedimentation problems over that of other pollution and degradation such as oil and chemical problems? Does the plan emphasize the water quantity problems as refected in most of the proposed CIP projects? The 1st paragraph under the CIP section (page 43) clearly states that structural improvements are needed and modifications -......'1.x•4. to the drainages in order to reduce peak runoff rates and subsequent erosion. Perhaps if all of the modifications were made in areas outside, the "natural drainages" there will be less sensitive area conflicts and impacts to mitigate. 4) I recommend that CIP projects be prioritized to promote upper watershed improvements ie. new detention, new or updated oil/water separators, and other controls related to water quantity before implementing lower watershed projects. Evaluate the effectivness of the upper watershed improvements with a monitoring program and determine if in -stream and lower watershed projects are appropriate. I feel that some of my comments from the November memo have been repeated here. The plan is well-written and includes detailed information that will help with project decisions. The most significant statement I would like to offer is that the problems are not in the drainages but originate outside of them. 0 RECEIVED • Cityof Tukwila File Number E -000�.. FEB - 61996 Department of Community Development TUKWILA PUBLIC WORKS ENVIRONMENTAL REVIEW ROUTING FORM F►/ TO: ❑ Building Planning tL7-Public Works ;,e � Police ,j Parks/Rec Project Name: It - sib fartw MiNANIza• PL1 Address: 3D0 E C C tai (J D .l 4uur-1 D7) Date Transmitted: 2 ' Response Due by: Z • 1 / '• Staff Coordinator: . 13 E12Lb1/0 • Date Response Received: L2 Ss —G.A..", 2 vft', c.wl.<.. �a Pw q�• - �1.e t�,+.�_ ( hs R-e&vFh )3i P. tom..) Tv>a The attached environmental checklist was received for this project. PIease review and provide the following information: a) Potential environmental impacts, b) how each should be. mitigated (i.e. SEPA condition, ordinance requirement, permit requirement etc.), c) recommended specific language as to how the mitigation measure should read, d) the policy basis for the recommended mitigation (i.e. adopted policy), e) the nexus between the recommended mitigation and the impact, and f) corrections to the checklist and supporting documentation. THIS INFORMATION IS IMPORTANT IN PROVIDING TIMELY AND ACCURATE SERVICE TO THE PUBLIC. Attach additional sheets if necessary. Instructions If you find the submittal incomplete and would like to request additional information, please inform the staff planner within five working days! 1. leer to /12r 04Q1,/Ay 7n 7 /-/-&2,r d Ae2/.29/F,E 2. Me/no Phi A6.i Sclu, /2 .doled 3,0/11'6 3. h'1 e o ,-/e ,$Q- -/ow l 0/ // a2r r t2 A Q 02//.06.. 6sckt, /2 w%// ffl2 e Comments Prepared b : J00e4no- 4 caDate: /rP Y 1 1g ECE OVED MAR 0 4 1996 COMMUNITY DEVELOPMENT • City of Tukwila Department of Public Works February 29, 1996 Wally Trial, Ph.D. ATT, Beth Schmoyer, P.E. Herrera Environmental Consultants 2200 Sixth Avenue, Suite 601 Seattle, Washington 98121 Subject: Fostoria Stormwater Quality Management Plan Grant Agreement No. G9300287 (City Project No. 90-DR17) City Budget Line Item No. 412/02.594.381.41.08 Dear Wally: • John W. Rants, Mayor Ross A. Earnst, P. E., Director ECM ED MAR 0 4 1996 COMMUNITY DEVELOPMENT City staff have reviewed your final draft of the Fostoria Stormwater Quality Management Plan and have the following comments to address in your final draft:., - _ Page 25'under Existing Tukwila Stormwater Quality and Pollutant Control- The City is constructing a permanent flow tote station at Southgate Creek where it intersects E. Marginal Way S and S 133 St. We will need additional equipment for continuous sampling for water quality and base flows at this station. The equipment we will require is a 264 C Teletote and sampling station (or equivalent). We estimate this equipment will cost $12,000. Please identify this equipment need. Also, inn future, we will need to monitor the basin water quality at the outfall located at 42 Ave S./Interurban Ave. S. to determine the impact?of applying the recommended BMP's and capital improvements to the basin. Please identify this monitoring program. - Pages 25 and 40, 41 indicate that Tukwila has_prepared a draft surface water ordinance that is currently under review.. It should be noted thatrDOE has approved the final draft of the ordinance as it went to the Council for adoption.7City and DOE staff worked closely _together-in_the _drafting of the documentand it adopted in December, 1995. Finally, this document includes design/permitting and_in now being applied for. - Page 39, paragraph one, after the first full sentence, we provide the following additional information: "Initial -coordination -With Val Vue' Sewer District will help uncover the risk areas through research of their as -built plans and TV reports. ?Also, Pat Brodin, Senior Sewer/Water Engineer for our office (433-0179) 2 ,the nearest'septic system known to be in operation currently are east of Military Road in the vicinity of Si 135th St. - Page 39, paragraph two, line five: Pat reports that "Observations by City staff arid Val-Vue pei`sorine1 of,' ;soap suds were -during major rain storm events: 7 J 6300 Southcenter Boulevard, Suite #100 • Tukwila, Washington 98188 • Phone: (206) 433-0179 • Fax (206) 431-3665 • • - It should be noted this document is now going through the programmatic environmental process. and individual project environmental reviews will occur for these projects as part of the normal PS &E process. Enclosed you will find review comments from Gary Schulz, Urban Environmentalist and Don Williams, Director of our Parks and Recreation Department. Please review and address the above comments in your fmal.draft document. Thank you. Sincerely, Phil Fraser Senior Engineer Enclosures (2) xc. Project File: 90-DR17.4 Cityt Tukwila 6200 Southcenter Boulevard • Tukwila, Washington 98188 MEMORANDUM John W Rants, Mayor RECEIVED TO: Alexia Berlow, Associate Planner MAR 0 4 1996 FROM: Don Williams, Parks and Recreation Director COMMUNITY DATE: February 13, 1996 DEVELOPMENT SUBJECT: Environmental Checklist Comments - Stormwater Management Plan I have no comments about the technical content or list of proposed projects. I do, however, have several questions. B. On page 50 - Project 10, third paragraph, it indicates the owner of the location of Pond #1 is the South Central School District. In fact, our records show King County Parks purchased the site, we believe, in 1974 and turned ownership over to the Tukwila Parks and Recreation Department in 1992. The funds to purchase the site were Forward Thrust Park Bond funds and as part of that ordinance (King County, around 1977 or 1978) it states the property can only be used for park and recreation purposes, not as a storm water retention pond. There are mitigation ways to work this out but, of course, they are not contained in the report. Is it the intent of the Public Works Department to keep this pond in the plan under these conditions? Projects 11 a and 1 lb seem to state additional work is proposed in the park property. We own land on both sides of 40/42 Avenue. Clarification is again needed on who owns the property for notification purposes and to obtain property owner approvals. Although these comments may not be considered damaging to the environment and we endorse the planned work, any potential errors in the report should be corrected or noted for proper notification to occur. I also noticed a lack of comment in the report E.C.L.about the impact of these proposed projects on salmon or other wildlife. The response to E.C.L. #5d adoption says "N/A." I'm wondering if the adoption of this plan that contains construction projects needs to address this issue or will each project as it comes in for approval (whose approval?) obtain individual review. If so, the agencies should be listed in question #10 or #7. DW/dc corrresp/don/alexia RECEIVED FEB 1 3 1996 Phone: (206) 433-1800 • City Hall Fax (206) 433-1833 COMMUNITY � U VCLOPM NT Control No. Epic File No. Fee: Receipt No. 1 ENVIRONMENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: Fostoria Water Quality Management Plan 2. Name of applicant: City of Tukwila 3. Address and phone number of applicant and contact person: 6300 Southcenter Blvd., Suite 100 Tukwila, WA 98188 433-0179; Phil Fraser 4. Date checklist prepared: 1/16/96 5. Agency requesting checklist City of Tukwila 6. Proposed timing or schedule (including phasing, if applicable): Adoption by the City Council of this water quality management plan February, 1996. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. Implementation of CIP portion of plan through Council adoption of future Surface Water CIP's. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. This checklist. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. No. Page 1 JAN 2 5 1996 Crh,ll;M11'rNIU1T ENVIRONMENTAL CHECKLIST 1 10. List any government approvals or permits that will be needed for your proposal. Adoption of Water Quality Management (WMQ) Plan by Tukwila City Council and approval of Tukwila City Mayor. 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. Section E requires a complete description of the objectives and alternates of your proposal and should not be summarized here. The Fostoria Basin Stormwater Quality Management (WMQ) Plan is the first step by the city to carry out comprehensive surface waster quality planning in the 560 acre Southgate Creek basin located within the Fostoria Drainage basin (see attached map). This plan characterizes stormwater runoff quality and pollutant sources; provides the regulatory framework, water quality goals and policies appropriate for the basin; then provides pollutant control alternatives with recommendations. In summary, this plan identifies water quality problems in the basin and provides water quality controls including capital improvement projects which will help solve these problems. 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 located in north Tukwila, in the Southgate Creek drainage basin which is a 560 - acre subwatershed within the 1,6000 -acre Fostoria basin located on the west side of the Duwamish River in Tukwila (see attached map). The Southgate Creek basin is generally bounded by Interurban Ave S./Green River on the east; S 148 St on the South; Military Rd/Pac Hwy on the West; and S 130 St on the North. 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Plan Map as environmentally sensitive? Portions of the Southgate Drainage Basin are in environmentally sensitive areas. Page 2 ENVIRONMENTAL CHECKL�iST B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous, other The basin generally slopes to the northeast toward the Duwamish River. The upper basin, west of state route (SR) -99 (Pacific Hwy), sits on a broad plateau at elevations ranging from about 200 feet to 400 feet (NGV datum). East of SR -99 and north of about S 140th Street, the plateau drops steeply down through steep ravines to the valley floor along the Duwamish River elevations range from 10 to 100 feet). Portions of the basin are flat and portions are hilly with some steep slopes. b. What is the steepest slope on the site (approximate percent slope)? The maximum slope is approximately 70%. 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. Glacially consolidated sand & silt. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. Some areas of bank erosion exist. Stream channels in the ravines are deeply incised as a result of erosion due to increased runoff from urbanized areas. Along the South fork, between Pac. Hwy. and 42 Ave S, the original county road has all but disappeared due to undermining and erosion. e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. N/A f. Could erosion occur as 'a result of clearing, construction, or use? If so, generally describe. N/A g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? N/A Page 3 ENVIRONMENTAL CHECK IST h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: The Plan calls for future CIPs to deal with flow related erosion problems that continue to threaten aquatic resources. 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. N/A b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. N/A c. Proposed measures to reduce or control emissions or other impacts to air, if any: N/A 3. Water a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. The planning area covers Southgate creek which has three forks tributary and discharges into the Duwamish River at Interurban Avenue South/S 42 Street. Page 4 ENVIRONMENTAL CHECKIPST 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. N/A 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. N/A 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities, if known. N/A 5) Does the proposal lie within a 100 year floodplain? If so, note location on the site plan. Portions of the planning area are within the 100 -year floodplain in the lower plateau, from 42 Ave S.to48AveS. 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. Page 5 NVJRONMENTAL CHECIPST b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities, if known. No. 2) Describe waste materials that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.) Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. None. c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. N/A Page 6 ENVIRONMENTAL CHEC ST 2) Could waste materials enter ground or surface waters? If so, generally describe. N/A d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: N/A 4. Plants a. Check or circle types of vegetation found on the site: X deciduous tree: alder, maple, aspen, other X evergreen tree: fir, cedar, pine, other X shrubs X grass X pasture crop or grain X wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other X water plants: water lily, eel grass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered? N/A c. List threatened or endangered species known to be on or near the site. None known. Page 7 ENVIRONMENTAL CHECKLIST d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: N/A 5. Animals a. Circle any birds or animals which have been observed on or near the site or are known to be on or near the site: Birds:. hawk, songbirds, migratory water fowl, other: Mammals: raccoons, squirrels, small rodents, other: Fish: bass, salmon, trout, herring, shellfish, other: 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. Not known. d. Proposed measures to preserve or enhance wildlife, if any: N/A Page 8 ENVIRONMENTAL CHECKL ST 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. N/A b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. N/A c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: N/A 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. No. 1) Describe special emergency services that might be required. None. 2) Proposed measures to reduce or control environmental health hazards, if any: Not applicable. Page 9 ENVIRONMENTAL CHEC ST b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? N/A 2) What types and levels of noise would be created by or associated with the project on a short-term or long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. N/A 3) Proposed measures to reduce or control noise impacts, if any: N/A 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? See Table 2, Appendix B b. Has the site been used for agriculture? If so, describe. No. c. Describe any structures on the site. There are many businesses and residential structures in the planning area. A list of the businesses can be found on Table C-1 in Appendix C of the attached WQM Plan report. Page 10 ENVIRONMENTAL CHEC T d. Will any structures be demolished? If so, what? N/A e. What is the current zoning classification of the site? Land use classifications can be found on Figure 3, Appendix A of the attached report. f. What is the current comprehensive plan designation of the site? Several designations for planning area. g. If applicable, what is the current shoreline master program designation of the site? N/A h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. Yes, Southgate Creek is designated as a stream and some steep slopes in the planning area are also designated environmentally sensitive areas. i. Approximately how many people would reside or work in the completed project? J• N/A Approximately how many people would the completed project displace? N/A k. Proposed measures to avoid or reduce displacement impacts, if any: N/A 1. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: A citizen's action committee was instrumental in the development of the policies and projects recommended in this plan. Page 11 ENVIRONMENTAL CHECKiT 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: N/A 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? No buildings are planned. Retaining walls will be limited to minimum required. b. What views in the immediate vicinity would be altered or obstructed? None. c. Proposed measures to reduce or control aesthetic impacts, if any: None. Page 12 ENVIRONMENTAL CHECKLL ST 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? None. b. Could light or glare from the finished project be a safety hazard or interfere with views? No. c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: None. 12. Recreation a. What designed and informal recreational opportunities are in the immediate vicinity? Southgate park. b. Would the proposed project displace any existing recreational uses? If so, describe. No. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None. Page 13 ENVIRONMENTAL CHECKLIST 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. None known. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None known. c. Proposed measures to reduce or control impacts, if any: None. 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. Several public streets serve the study area. Public facilities proposed in the plan would utilize public rights of ways for access. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Public transit routes exist in the service area. Proposed water quality facilities are not dependent on public transit. c. How many parking spaces ►vould the completed project have? How many would the project eliminate? Parking for maintenance of the proposed facilities as part of the PS & E phase of plan development. Page 14 ENVIRONMENTAL CHECKKST d. 'Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). No. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. This project will not generate added daily traffic for maintenance of new water quality facilities, only periodic trips (quarterly/annually) for maintenance/monitoring purposes. g. Proposed measures to reduce or control transportation impacts, if any: None. 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. Only for normal maintenance. b. Proposed measures to reduce or control direct impacts on public services, if any. None. Page 15 ENVIRONMENTAL CHECK�ST 16. Utilities a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other. N/A. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water quality facilities proposed are only public facilities proposed as part of the recommendations in the CIP portion of the plan. C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Submitted: Page 16 ENVIRONMENTAL CHECKAT TO BE COMPLETED BY APPLICANT D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (do not use this sheet for project actions) Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? Implementation of this plan will result in reduction/elimination of toxic/hazardous substances and other pollutants into Southgate Creek and the Duwamish River. Proposed measures to avoid or reduce such increases are: The programmatic elements of the Fostoria WQM Plan to reduce storm water pollutants include storm water mapping; enforcement of the City's recently adopted Surface Water Management Ordinance; Community based projects (i.e. Stenciling Program); reduction of failed sanitary septic systems; illegal connection surveys; public education on handling/discharge/disposal of toxic materials; and, technical assistance program for local businesses. Implementation of a proposed series of CIP's in the Plan will provided structural improvements such as detention/sedimentation ponds and/or vaults; stream channel stabilization; and, high flow by-pass systems to reduce over souring and erosion of the stream/water courses and subsequent excessive silting up of lower portions of Southgate Creek and Duwamish River. 2. How would the proposal be likely to affect plants, animals, fish, or marine life? The reduction of silt, toxins and other pollutants in Southgate Creek Basin will improve water quality and fish habitat. General improvements to the ecosystem should improve the numbers and quality of the fishery to its potential. Proposed measures to protect or conserve plants, animals, fish, or marine life are: The programmatic elements of the Fostoria WQM Plan to reduce storm water pollutants include storm water mapping; enforcement of the City's recently adopted Surface Water Management Ordinance; Community based projects (i.e. Stenciling Program); reduction of failed sanitary septic systems; illegal Page 17 ENVIRONMENTAL CHECKLIST connection surveys; public education on handling/discharge/disposal of toxic materials; and, technical assistance program for local businesses. Implementation of a proposed series of CIP's in the Plan will provided structural improvements such as detention/sedimentation ponds and/or vaults; stream channel stabilization; and, high flow by-pass systems to reduce over scouring and erosion of the stream/water courses and subsequent excessive silting up of lower portions of Southgate Creek and Duwamish River. 3. How would the proposal be likely to deplete energy or natural resources? It will not. Proposed measures to protect or conserve energy and natural resources are: N/A 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? The programmatic elements of the plan will reduce silt, toxins and other pollutants in the various reaches of Southgate Creek, and sedimentation/pollutant loading to the Duwamish River. Some CIP's will require flow diversion or instream detention/desiltation vaults to reduce sediments/flows to non -scouring levels. Proposed measures to protect such resources or to avoid or reduce impacts arc: Goal I of the WQM Plan is: To improve water quality of Southgate Creek in order to develop and maintain the attributes of a high quality stream and watercourse which is located in an urbanized setting. The adoption of this goal as part of the plan and carrying out the programmatic and CIP's recommended to achieve this goal is the purpose of this plan. Some of the CIP's will require flow diversion or instream detention/desiltation vaults to reduce sediments/flows to non -scouring levels. however, final design for placement of such water quality control facilities and the methods by which these facilities are constructed will take into consideration the natural features and functions of the watercourses, wetlands including the supportive ecosystems, to assure least negative impacts occur. Page 18 ENVIRONMENTAL CHECK ST 5. How would the proposal be likely to affect land and shoreline use, including whether it would allow or encourage land or shoreline uses incompatible with existing plans? No structures are proposed in the Duwamish River by this plan. Through adoption of the goals, policies, programmatic program and CIP's, and implementation of these planning elements, the pollutant loading and sediment loading at the Duwamish River at the 42nd Ave S. bridge just east of Interurban Avenue S. will be reduced. This action will provide incremental improvement to the overall water quality to the downstream Duwamish River. hi turn, incremental improvement to the water quality of the shoreline of the Duwamish will also be realized through the implementation of this plan. Proposed measures to avoid or reduce shoreline and land use impacts are: This plan proposes to provide the positive impacts to the shoreline as stated above. How does the proposal conform to the Tukwila Shoreline Master Plan? This plan conforms to the Tukwila Shoreline Master Plan in terms of protecting water quality and fish and wildlife habitat, by reducing or eliminating the discharge of sediments, toxins and other pollutants from the Fostoria/Southgate Creek basin to the Duwamish River. 6. How would the proposal be likely to increase demands on transportation or public services and utilities? Added water quality facilities are proposed by this plan. Proposed measures to reduce or respond to such demand(s) are: Although added water quality facilities are planned, the amount of high level maintenance that is now on going will be reduced by the reduced/controlled flows and providing for upstream catchment facilities. 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the environment. This plan brings Tukwila in greater compliance with requirements of the State DOE. Page 19 ENVIRONMENTAL CHEC ST 8. Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what policies of the Plan? No. Proposed measures to avoid or reduce the conflict(s) are: N/A Page 20 ENVIRONMENTAL CHECKLST • E. SUPPLEMENTAL SHEET FOR ALL PROJECT AND NON PROJECT PROPOSALS The objectives and the alternative means of reaching the objectives for a proposal will be helpful in reviewing the foregoing items of the Environmental Checklist. This information provides a general overall perspective of the proposed action in the context of the environmental information provided and the submitted plans, documents, supportive information, studies, etc. 1. What are the objectives of the proposal? In developing a stormwater pollution control strategy for the Fostoria/Southgate Creek basin, the following goals were identified to guide the preparation of this plan: * Develop alternatives to control nonpoint pollution sources * Recommend preferred control alternatives for implementation * Develop goals and policy statement for protecting water quality in Southgate Creek * Provide direction for city sponsored capital improvements and program activities. * Establish citizens action committee to provide input to the Fostoria Basin Stormwater Quality Management Plan * Coordinate with neighboring jurisdictions and state agencies. Goals that were accomplished through the technical preparation of this project are as follows: * Identified drain basin and stream characteristics including storm drainage system, land use, location and types of businesses operating in the basin. * Identified stormwater quality concerns and potential pollutant sources in basin through drain sampling and complication of existing data from previous studies and agency files (e.g., permitted facilities, spill records, contaminated sites). * Documentation of applicable stormwater regulations * Establishment of water quality goals and policies * Identification, evaluation, and prioritization of appropriate stormwater pollution control alternatives. Page 21 ENVIRONMENTAL CHECI ST 2. What are the alternative means of accomplishing these objectives? Both programmatic and structural control alternatives were explored to develop the final recommendations. The development of these alternatives can be found under "Stormwater Pollution Control Alternatives" Chapter from page 35 to page 60 of the attached report. 3. Please compare the alternative means and indicate the preferred course of action: Comparison of the programmatic and structural control alternatives are provided under "Stormwater Pollution Control Alternatives Chapter from pages 36 to page 60 of the attached report, including the use of the Citizen Action Committee for project ranking. The preferred course of action or recommendations are found under "Summary and Recommendations" Chapter from pages 61 through 66 of the report. 4. Docs the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? No Proposed measures to avoid or reduce the conflict(s) are: None. Page 22 MEMORANDUM DRAFT TO: Phil Fraser, Senor Enginerro FROM: Gary Schulz, Urban Environmentalist - DCD DATE: November 16, 1995 RE: Fostoria Stormwater Quality Plan. My comments for the draft management plan are provided below. I have no major comments on the first section - Water Quality Programs. The proposed CIP's are attempting to deal with local problems occurring within our drainage systems. However, there is a heavy emphasis placed on repair and maintenance. The fishery element is somewhat hidden in the recommendations. My general observations are listed first followed by project discussion. 1) This draft fails to recognize the sensitive areas element in planning surface water improvements. Even though much of Tukwila is developed,, there are still segments of watercourses that can be treated as natural and have elements to support aquatic life. The vegetated areas with tree cover will continue to resist erosion and can regenerate if frequent storm flows can be reduced. 2) Wet vaults are low on theft of preferred BMP�s because they cannot provide a biological function for water quality improvement including nutrient pollutant reduction. _ Significant water quality improvements can be achieved with open systems. Wet vaults will likely require more maintenance. Please' see attache information. 3) Without knowing exact locations of the closed drainage system, I stilli recommend that a regional detention facility be incorporated into the basin plan? Implementation 1rof all the plan elements will take years and we should allow for change or unanticipated development opportunities. Small individual detention vaults may not provide the long term goals of improving water quality and. reducing erosion within the City. Continued development of the remaining pervious land should also be considered in this plan 4) If a commitment to restoring a fishery somewhere in the system is a possibility, the current draft plan would likely change. All proposed in -stream stabilization will be subject to the Sensitive Areas Ordinance, but additionally, would need an aquatic habitat element. This generally conflicts with designs that include hard surfaces to stabilize and promote conveyance of stormwater. The specific commentsgabout the draft Plan are listed as follows: N. Fork Southgate - Install detention at upper end of drainage then monitor to see if any channel improvements are needed. Middle Fork Southgate - Both North and Middle forks have considerable amount of undeveloped area at the upper portion just east of Pac Highway. Some of the undeveloped area is relatively flat and could be considered for developing small ponds. This channel is narrow and does not appear to be receiving large runoff flows. Fostoria Basin Stormwater Memo November 16, 1995 Page 2 South Fork Southgate - Some of the channel above 40th Avenue S. was modified as part of a stabilization - project about 2 years ago. Not shown on the basin plan map is a small tributary ravine that joins the middle fork above 40th Avenue S. This is also mapped on the Riverton Basin CADD map. The inlet to Southgate Creek was stabilized; however, this ravine is eroding rapidly and contributing a significant amount of sediment to the system. Most of the runoff this channel receives is from a large pipe under Pac Highway. Even though piping is discouraged in the SAO, the gradient is steep enough to consider a Driscoll pipe connection to the bottom of the ravine. A sediment vault may also be needed at the ravine bottom. Southgate Creek (downstream of Middle & North Forks) - The Creek drainage improvements through the "horse pasture" would likely require an easement or acquisition. Rerouting .or creating a new channel within the ROW of 133rd and 131st could also become a fish enhancement. Because the horse pasture is wetland, creek flows are partially detained as it meanders through the area. Altering this area could change the rates of flow to the downstream system. Also, there is no discussion of the probable fish barrier that exists just upstream - culvert running under S. 133rd. SUMMARY The upper watershed along Pac Highway is not fully developed and there may be some future opportunity for open detention facilities. Would the proposed vaults (Project 12) be installed within the ROW? Has there been any discussion of future improvements to Pacific Highway in the north end of the Fostoria drainage basin? I have heard of roadway and ROW improvements for the future. Some of the mapped vault locations appear to be in the Gilliam Creek Basin. Even though wet vaults are not as effective for pollutant removal, they may serve a needed stream stabilization function by being installed in the developed upper watershed. Consideration should be given to how much maintenance they would require. For reference, I have attached some information taken from the Ecology Stormwater Technical Manual. I recommend that any stream/watercourse stabilization be determined as necessary before implementation. Any detention facilities that are planned should be evaluated for effectiveness prior to downstream alterations. Coordination with SeaTac may be important to future stormwater planning in this basin. Outright acquisition and public easements could provide some viable detention. Also, future improvements to Pac Highway in this area have been discussed and could offer significant design changes to the existing system. • • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN III -4.5 STANDARDS AND SPECIFICATIONS FOR VAULTS AND TANKS III -4.5.1 BMP.RD.15 Wet Vault/Tank Purpose and Definition Wet vaults and tanks are underground facilities used for the storage of surface water, and are typically constructed from reinforced concrete (vaults) or corrugated pipe (tanks). Wet vaults and tanks are typically concrete or structural facilities designed to provide runoff treatment through the use of a permanent pool of water. Streambank erosion control can also be provided by adding a "live storage" volume above the permanent pool. Figures III -4.17 and 1I1-4.18 illustrate tank/vault systems. Planning Considerations See BMP.RD.05, Wet Pond (Conventional Pollutants). Additional planning considerations are provided below. If a wet vault/tank is designed to provide runoff treatment but not streambank erosion control it must be located "off-line" from the primary conveyance/detention system. Flows above the peak flow for the water quality design storm (i.e., 6 - month, 24-hour event) must bypass the facility in a separate conveyance to the point of discharge. A mechanism must be provided at the bypass point to take the facility "off-line" for maintenance purposes (see Section III -3.7 for isolation/diversion structures). Limitations Wet vaults/tanks cannot provide the equivalent level of treatment accomplished by wet ponds and constructed wetlands because neither biological uptake nor vegetative filtration are available as pollutant removal mechanisms. Gravity -settling of suspended solids is the primary removal mechanism but vaults/tanks are unlikely to be as effective as open ponds in removing particulates becau-se little or no soil layer exists in which to permanently stabilize trapped sediments. Also, being underground, vaults and tanks are more difficult to inspect and maintain. Therefore, they shall only be permitted for use on small sites, and then only after it has been demonstrated to the satisfaction of the local government that more desirable BMPs are not practicable, according to the BMP selection process outlined in Chapter I-4. Other Wet vaults/tanks shall be a minimum of 20 feet from any structure, property line, NGPE, and from any septic tank/drainfield. All facilities shall be a minimum of 50 feet from any steep slope. A geotechnical report must address the potential impact on a steep slope. Design Criteria The design criteria for a wet vault/tank shall be the same as for BMP RD.05, Wet Pond (Conventional Pollutants). Sizing Wet Vaults/Tanks Volume/outflow analysis shall be in accordance with the hydrologic methods outlined in Chapter III -1, with appropriate correction factors. Restrictor/orifice structure design shall be per Section III -2.4. III -4-53 FEBRUARY, 1992 • STORM*ATE MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN III -4.5.2 BMP RD.20 Extended Detention Dry Vault/Tank Purpose and Definition An Extended Detention Dry Vault/Tank is physically similar to BMP RD.15 (Wet Vault/Tank) but provides only streambank erosion control. Dry vaults/tanks are not to ba used for runoff treatment purposes because of their limited pollution removal capabilities. Dry Vaults/Tanks must always be preceded by a BMP which has treated runoff up to the 6 -month, 24-hour design storm. This BMP accomplishes streambank erosion control by detaining runoff and then releasing it a reduced flows in order to meet the standards established by Minimum Requirement 05 (see Chapter I-2). Figures III -4.17 and III -4.18 illustrate detention vault/tank systems. Planning Considerations Limitations Dry vaults and tanks provide little water quality benefits compared to open ponds and wet vaults/tanks. Also, being underground, are more difficult to inspect and maintain. Therefore, they shall always be preceded by treatment BMPs. Vaults/tanks shall be permitted for use only on small sites, and then only after it has been demonstrated, to the satisfaction of the local government, that more desirable BMPs are not practicable,according to the BMP selection process outlined in Chapter.I-4. Design Criteria • An extended detention'dry vault isdesigned only to provide streambank erosion control. The design methods and procedures provided in Chapter III -1 shall be used. A multiple orifice design will be necessary in order to meet the three release requirements, i.e., 50% of the existing condition 2 -year, 24-hour peak flow; maintain existing condition peak flow rates for the 10 -year and 100 -year, 24-hour events. A correction factor must be applied to the calculated detention volume, as discussed in Section III -1.2; in order to account for weaknesses in current hydrologic analysis methods. Construction and Maintenance Criteria See BMP RD.15, Wet Vault/Tank and Table III -4.7. III -4-60 FEBRUARY, 1992 FOSTORIA BASIN Stormwater Quality Management Plan Prepared for City of Tukwila Department of Public Works 6300 Southcenter Boulevard, Suite 100 Tukwila, WA 98188 Prepared by Herrera Environmental Consultants, Inc. 2200 Sixth Avenue, Suite 601 Seattle, Washington 98121 Telephone: 206/441-9080 March 1996 CONTENTS INTRODUCTION 1 GOALS AND OBJECTIVES 1 TECHNICAL APPROACH 2 DRAINAGE BASIN CHARACTERISTICS 5 STORM DRAINAGE SYSTEM 5 Central Drain 6 East Drain 6 WATERCOURSE RATING 7 LAND USE 8 PREVIOUS WATER QUALITY STUDIES IN SOUTHGATE CREEK 8 BUSINESS INVENTORY 10 NPDES-Permitted Facilities 10 Contaminated Sites 11 HOUSEKEEPING PRACTICES 13 SPILL RECORDS 14 STORMWATER QUALITY AND POLLUTANT SOURCE CHARACTERIZATION . 17 STORM DRAIN SAMPLING PROGRAM 17 Sampling Stations and Events 17 Sampling Methods 18 RESULTS 18 Comparison to State Water Quality Standards 18 Dissolved Versus Total Metals Concentrations in Winter Storm Flow Samples 19 Comparison of Results from the Three Sampling Events 20 Comparison with Runoff Data from Other Urban Areas 22 REGULATORY FRAMEWORK 23 STORMWATER REGULATIONS 23 Puget Sound Water Quality Management Plan 23 National Pollutant Discharge Elimination System 24 State Growth Management Act 25 EXISTING TUKWILA STORMWATER QUALITY AND POLLUTANT CONTROL PROGRAMS 25 1993 Surface Water Management Comprehensive Plan 25 Draft Tukwila Comprehensive Plan 27 Local Ordinances 27 Ongoing Tukwila Pollution Control Activities 30 WATER QUALITY GOALS AND POLICY 33 STORMWATER POLLUTION CONTROL ALTERNATIVES 35 ii SUMMARY OF EXISTING STORMWATER QUALITY PROBLEMS 35 STORMWATER QUALITY PROGRAM 37 Stormwater System Mapping 37 Enforcement Program to Support Surface Water Management Ordinance 37 Catch Basin Cleaning 37 Standard Procedures for Maintaining Public Storm Drainage Facilities 38 Illicit Connection Surveys 38 Drainage Plan Reviews 40 Technical Assistance Program for Local Businesses 40 Public Education 41 Community -Based Projects 42 CAPITAL IMPROVEMENT PROJECTS 43 Coordination with Existing CIPs 43 Other Potential Stormwater Quality CIPs in Southgate Creek Basin 46 COST ESTIMATES FOR STORMWATER POLLUTION CONTROL ALTERNATIVES 56 COMPARISON OF STORMWATER POLLUTION CONTROL ALTERNATIVES 57 Capital Improvement Projects 57 Water Quality Programs 58 Citizens Action Committee Project Ranking 59 SUMMARY AND RECOMMENDATIONS 61 CAPITAL IMPROVEMENT PROJECTS 61 WATER QUALITY PROGRAM 64 REFERENCES 69 Appendix A: Figures Appendix B: Tables Appendix C: Business Inventory Appendix D: Available Stormwater Publications Appendix E: Potential Detention Pond Sites in Southgate Creek Basin (Perteet 1993) iii FIGURES (APPENDIX A) 1 Southgate Creek drainage basin. 2 Southgate Creek stream reaches identified for watercourse rating. 3 Land use in the Southgate Creek drainage basin. 4 Businesses operating in the Southgate Creek basin. 5 Sampling stations at the Fostoria Park Industrial Center. 6 Sampling stations in Southgate Creek. 7 Comparison of flow in Southgate Creek tributaries. 8 Comparison of pH data in Southgate Creek. 9 Comparison of dissolved oxygen concentrations in Southgate Creek samples. 10 Comparison of fecal coliform bacteria numbers in Southgate Creek samples. 11 Septic system failures in the Southgate Creek basin. 12 Comparison of dissolved copper concentrations in Southgate Creek samples. 13 Comparison of dissolved lead concentrations in Southgate Creek samples. 14 Comparison of dissolved zinc concentrations in Southgate Creek samples. TABLES (APPENDIX B) 1 Watercourse ratings for streams in the Southgate Creek basin. 2 Land use in the Southgate Creek basin. 3 Southgate Creek base flow sampling results from 1991 study. 4 Southgate Creek storm flow sampling results from 1991 study. 5 Results for pH in surface and ground water samples collected from the Fostoria Industrial Park Center. 6 Spills reported in the Southgate Creek basin, 1991-1995. 7 Washington state water quality standards for Class A freshwaters. 8 Results from summer base flow samples collected in Southgate Creek. 9 Results from winter base flow samples collected in Southgate Creek. 10 Results from winter storm flow samples collected in Southgate Creek. 11 Comparison of Southgate Creek water quality data with data from other urban areas in Puget Sound. 12 Detention requirements for the upper Southgate Creek basin. 13 Summary of estimated costs for stormwater quality improvement alternatives. 14 Comparison of stormwater quality improvement alternatives iv INTRODUCTION The Fostoria Basin Stormwater Quality Management Plan has been developed as an important first step in the city of Tukwila's efforts to improve water quality in Southgate Creek and its associated drainage area. The Southgate Creek drainage basin is a subwatershed within the 1,600 -acre Fostoria basin located on the west side of the Duwamish River in Tukwila. An earlier study (KCM 1986) investigated drainage conditions in the larger Fostoria basin and developed recommendations for improving the existing drainage system, which included drainage improvements in Southgate Creek. This study in Southgate Creek focuses primarily on water quality issues, although water quantity and flow concerns are considered where they affect water quality. The 560 -acre Southgate Creek basin is highly urbanized. Land use is predominantly residential interspersed with some commercial and light industrial areas. This plan focuses not only on identifying specific water quality problems within the basin, but also on specific controls including capital improvement projects, which can be implemented to help solve these problems. It is organized into separate sections dealing with the drainage basin characteristics, stormwater quality and pollutant source characterization, regulatory framework, water quality goals and policy, stormwater pollution control alternatives, and recommendations. The sections characterizing the basin and pollutant sources describe the results of field investigations conducted to develop an understanding of the stormwater quality issues and concerns associated with Southgate Creek. The water quality and aquatic resource problems identified during the field investigations helped to define the goals and stormwater pollution control alternatives of the stormwater quality management plan. The recommendations section identifies a prioritized list of capital improvement projects that can be implemented by the city to improve stormwater quality within the Southgate Creek Basin. Figures and tables cited in the report are presented in Appendices A and B. GOALS AND OBJECTIVES The overall objectives of the Fostoria Basin Stormwater Quality Management Plan are 1) to characterize the quality of stormwater runoff generated within the Southgate Creek basin, 2) to identify stormwater control projects and/or management practices that will serve to improve the quality of stormwater and the quality of waters in Southgate Creek, and 3) in conjunction with a citizens action committee, rank nonpoint pollution problems and target areas for improvement. In developing a stormwater pollution control strategy for the basin, the following specific goals were identified to guide preparation of this plan: 335/plan • Develop alternatives to control nonpoint pollution sources • Recommend preferred control alternatives for implementation 1 Herrera Environmental Consultants and mapping a list of businesses operating in the basin. Using this information, a stormwater sampling program was designed and implemented to characterize the quality of stormwater runoff in Southgate Creek. The stormwater quality information obtained was then used in conjunction with the initial basin characterization data to identify potential pollutants of concern and to assess potential contaminant sources within the basin. After the problems within the basin were identified, potential controls were selected and evaluated based upon their efficacy and feasibility for application in the Southgate Creek basin. 335/plan 2 Herrera Environmental Consultants These controls range from improved facility maintenance to public education to structural controls that could be implemented under the city's capital improvement program. Recommended controls are discussed herein as part of this plan. 335/plan Herrera Environmental Consultants 335/plan 4 Herrera Environmental Consultants DRAINAGE BASIN CHARACTERISTICS STORM DRAINAGE SYSTEM The 560 -acre Southgate Creek drainage basin is located in the northwest part of Tukwila, bounded on the south by S 148th Street, on the north by S 128th Street, on the east by Interstate - 5, and on the west by Military Road (Figure 1). The basin generally slopes to the northeast toward the Duwamish River. The upper basin, west of state route (SR) -99 (Pacific Highway), sits on a broad plateau at elevations ranging from about 200 feet to 400 feet. East of SR -99 and north of about 140th Street S, the plateau drops steeply down to the valley floor along the Duwamish River (elevations ranging from 10 to 100 feet). The Southgate Creek drainage basin is shown in Figure 1. Southgate Creek is comprised of five separate tributaries: the south fork, middle fork, north fork, central drain, and east drain. Most of the natural drainage system has been modified to accommodate urban development. As a result, the drainage system consists of a series of streams and ditches interspersed with culverts, flumes, and pipes. The south, middle, and north forks of Southgate Creek drain an area of approximately 245 acres located west of 42nd Avenue S. The south fork, the largest of the three branches, collects runoff from the predominantly residential areas west of 42nd Avenue S and south of S 140th Street, as well as about 4,800 feet of SR -99 and adjacent commercial areas. Total basin area contributing to the south fork is approximately 560 acres. The middle fork serves a mostly residential area of about 12 acres located west of SR -99, including about 900 feet of SR -99. Springs emerging along the hillside east of SR -99 contribute base flow to the middle fork. The north fork receives runoff from the residential area north of S 140th Street located between 37th Avenue S and 35th Avenue S, and about 650 feet of SR -99. Runoff from the upper portions of the Southgate Creek drainage system is collected in a system of roadside ditches and pipes, then routed through culverts underneath SR -99. Below SR -99, the three branches open into steep, narrow ravines that run down the hillside to the valley floor. The stream channels in the ravines are deeply incised as a result of erosion due to increased runoff from urbanized areas. There are no regional detention facilities in the basin. Runoff from some of the commercial areas is detained before being discharged offsite. However, runoff from most of the residential areas and SR -99 is not detained and is released directly to existing drainage ditches and channels. Sediment eroded from the steep ravines is then deposited in the relatively flat areas of the drainage system along the valley floor, creating maintenance problems in ditches and culverts that serve the lower basin. The south, middle, and north forks of Southgate Creek merge just upstream of S 133rd Street. Flow is routed under S 133rd Street and 42nd Avenue S in a 36 -inch culvert. East of 42nd Avenue S, the culvert opens into a braided channel where it crosses an open field and pasture. Much of the stream channel has filled in with sediment, leaving only a braided channel that 335/plan 5 Herrera Environmental Consultants overflows during large storm events, flooding the field and pasture. At the northeast end of the pasture, runoff enters a ditch that runs along the south side of S 134th Street and travels north to a 42 -inch culvert under S 133rd Place. From S 133rd Place, the Southgate Creek channel runs northeast through an open field to a 66 -inch pipe that passes underneath SR -599. The stream channel in this area is straight with a uniform cross-section and is vegetated with reed canarygrass, which tends to choke off flow in the ditch, thereby reducing its carrying capacity. An 11 by 7 -foot arch culvert equipped with a series of weirs has been installed at the downstream end of the culvert under SR -599. The weirs act as a fish ladder allowing fish to migrate from the Duwamish River upstream into the Southgate Creek drainage. Central Drain The central drain begins as a small channel near 44th Avenue S and S 140th Street, collecting runoff from the Foster High School and Showalter Junior High School campuses and the St. Thomas Church property. The channel runs north between 45th Avenue S and 44th Avenue S, crossing under S 137th Street in a 24 -inch culvert. North of S 137th Street, the central ditch enters a steep ravine. Naturally occurring erosion along this steep section of the channel has been accelerated due to increased flow from urban development. At S 135th Street, the channel merges with a ditch that collects runoff from residential areas located along the west and south side of S 135th Street. The stream then crosses underneath S 135th Street in a 48 -inch culvert and enters an asphalt -lined swale that runs along the north side of S 135th Street. The asphalt - lined swale discharges to an open channel that runs through the northwest part of the industrial park located at S 133rd and 5 134th Street and then enters a 30 -inch pipe that connects with the bypass system on S 133rd Street. A second culvert enters the asphalt -lined swale approximately 175 feet north of the 48 -inch culvert. This 24 -inch culvert carries runoff from the mostly undeveloped area south of Southgate Park and the hillside immediately east of 43rd Avenue S. A 10 -acre, 41 -lot residential development (Fosterview Estates) is proposed to be constructed in the area south of Southgate Park. Under the proposed drainage plan, a 12 -inch culvert under 43rd Avenue S that currently conveys runoff from the area south of Southgate Park will be plugged. Runoff from this area will be routed north along the west side of 43rd Avenue S in a 24 -inch pipe to S 133rd Street. In addition, the city plans to install a stormdrain along S 139th Street to convey runoff for part of 42nd Avenue S to the 24 -inch drain to be constructed at 43rd Avenue S. At S 133rd Street, flow enters a grass swale running along the south side of S 133rd Street, then connects with the Southgate Creek system at S 134th Street. East Drain The east drain begins as a small ditch that runs along the west side of Interstate -5, starting just north of S 144th Street and passing through an area of low-density residential development north of S 138th Street. Riparian vegetation is well established throughout most of this section; the channel is either wooded or landscaped where it crosses through private yards. Two wetland areas exist in the reach between S 136th Street and S 138th Street. Runoff from residential areas west of Macadam Road S enters the east drain near S 137th Street via a 24 -inch culvert under Macadano Road S. Small ground water seeps also exist in this area, contributing base flow to the stream. North of S 136th Street, the stream channel crosses through several residential yards and 335/plan 6 Herrera Environmental Consultants passes under 48th Avenue S in a 24 -inch culvert. Beyond 48th Avenue S, the channel crosses under one private driveway and enters a ditch that runs along the west side of S 134th Street. The ditch in this reach is straight and is lined with reed canarygrass. Because the channel gradient is low, sediment tends to deposit in the ditch, reducing channel carrying capacity. In addition, many of the culverts under the driveways on the west side of the road are undersized, causing flow to back up in the ditch. Runoff from light industrial areas west of S 134th Street enters at several locations along the ditch downstream of 48th Avenue S. Runoff from an industrial park located at the west side of S 134th at S 133rd streets is routed through a 4 -foot -diameter detention pipe prior to discharge to the ditch. Runoff from other light industrial and commercial areas along the west side of S 134th Street appears to discharge directly to the ditch without detention. During large storm events, flow overtops the ditch at a low spot in the roadway (approximately 500 feet north of the intersection with 48th Avenue S) and floods S. 134th Street. Under these conditions, roadway runoff can enter a private drainage system located on the east side of S 134th Street, either by overflowing into catch basins adjacent to the roadway or via an overflow pipe that connects the ditch on the west side of S 134th Street directly to the private system on the east side of the road. The private drainage system is equipped with oversized pipe for detention and discharges to a small ditch located east of the industrial park. The ditch then discharges directly to the large bypass system on S 133rd Street. The city is currently designing a road improvement project along S 134th Street to raise this section of the roadway and eliminate the flooding problem. As part of this project, runoff from about 300 feet of roadway will be collected and piped directly to the bypass on S 133rd Street. The central drain and east drain merge near the corner of S 133rd Street and S 134th Street. A bypass structure at this location diverts most of the flow from these two drainages to a 4- by 8 - foot box culvert that runs east along S 133rd Street to Interurban Avenue S. Flow is then routed north along Interurban Avenue S in a 72 -inch pipe to Southgate Creek just south of the 42nd Avenue S bridge over the Duwamish River. A portion of the runoff from the central drainage system, from a section of pipe that runs along 43rd Avenue S from about S 135th Street to S 133rd Street, is not captured in the bypass and merges with Southgate Creek at S 133rd Street. WATERCOURSE RATING In 1990, Tukwila conducted a study to evaluate the habitat value of streams within city jurisdiction (Jones and Stokes 1990). The study was undertaken to establish a watercourse rating system that could be incorporated into the city sensitive areas ordinance. Watercourses were rated on a scale of 1 (high habitat value) to 3 (low habitat value). Buffer requirements for new development were then established based on the rating system. Watercourse ratings are summarized in Table 1 for streams within the Southgate Creek basin (Figure 2). Most of the stream channels in the basin exhibit low habitat value and are classified as type 3 watercourses because of extensive erosion damage and associated impacts from urban 335/plan 7 Herrera Environmental Consultants development. Only the section of the east drain located between Macadam Road S and S 136th Street (see reach 15-1 on Figure 2) and the section of the central drain between S 135th Street and S 137th Street (see reach 15-2 on Figure 2) contain high quality habitat and are classified as type 1 watercourses. The following stream reaches are classified as type 2 watercourses, having moderate habitat value: • Southgate Creek upstream of SR -599 • Southgate Creek between S 133rd Street and S 133rd Place • Station F—Southgate Creek at outlet from 36 -inch culvert under S 133rd Street (base flow and storm flow) ' 335/pian 8 Herrera Environmental Consultants , • Station C-2—Southgate Creek at outlet from 48 -inch culvert under S 133rd Place (base flow and storm flow) ■ Station H—Ditch on S 134th Street at intersection of S 133rd Street, i.e., the east drain (base flow). Temperature, pH, dissolved oxygen, and specific conductance were measured in the base flow samples collected from all three stations on May 21, 1991. Metals, nutrients, biochemical oxygen demand, chemical oxygen demand, and fecal coliform bacteria were measured in the storm flow samples collected from stations H and C-2 on May 24, 1991. Results are summarized in Tables 3 and 4. The water quality results for the summer base flow samples are all within acceptable ranges for aquatic life. Specific conductance measured at station H was about 10 times greater than at stations F and C-2, which indicates that ground water contributions may be more significant at this site. Federal water quality criteria and state water quality standards for metals are dependent upon water hardness. Because hardness was not analyzed in the Southgate Creek water samples, direct comparison with available criteria and standards is not possible. For the purposes of this evaluation, a hardness of 65 milligrams per liter (mg/L) as calcium carbonate (CaCO3) is assumed for storm flow conditions, based on the storm flow data collected in Southgate Creek in 1994 for the current study. The 1991 samples collected from Southgate Creek were analyzed for total metals. Therefore, these data are compared to the federal ambient water quality criteria, which are based on total recoverable metals concentrations, as opposed to the state water quality standards which are based on dissolved metals concentrations. With a hardness of 65 mg/L, the copper concentration at both station H (11.8 micrograms per liter [µg/L]) and station C-2 (10.4 µg/L) would exceed the federal water quality criterion for chronic toxicity to aquatic life (8.2 µg/L), while the concentration at station H would equal the acute toxicity criterion (11.8 µg/L). Zinc concentrations at both stations (44 µg/L at station H and 41 µg/L at station C-2) are below the water quality criteria (73.6 µg/L for chronic toxicity and 81.2 µg/L for acute toxicity). Cadmium concentrations at both stations are below the acute toxicity criterion for aquatic life (2.41 µg/L). However, the analytical detection limit for cadmium (2 µg/L) is higher than the chronic toxicity criterion (0.81 µg/L). Therefore, no conclusions can be drawn concerning the chronic toxicity of cadmium in Southgate Creek using the 1991 data. The fecal coliform bacteria numbers measured in the two 1991 stormwater samples collected from Southgate Creek exceed the state standard for Class A waters (excellent quality) (the standard is established at a geometric mean of 100 colony -forming units per 100 milliliters [cfu/100mL] with no more than 10 percent greater than 200 cfu/100 mL). Fecal coliform bacteria are present normally in the intestinal tracts of warm-blooded animals (human and nonhuman) and therefore are commonly used in water and wastewater analyses as indicators of contamination by fecal material and associated pathogens. In an urban environment, sources of fecal contamination include domestic pets, birds, and other urban wildlife, as well as human 335/plan 9 Herrera Environmental Consultants waste. A recent study in the Pipers Creek watershed in north Seattle found that fecal contamination in stormwater runoff was contributed entirely from animal sources (i.e., dog, cat, and bird) rather than human sources (Herrera 1993). This study used a forensic method based on genetic labeling techniques to differentiate fecal contamination contributed from various animal species and humans. The greatest number of matches between receiving water and source isolates were of domestic cat origin. However, due to the limitations of the forensic technique, it is unclear whether cats were the primary source. The fecal coliform bacteria counts in samples collected from Southgate Creek are within the range of values found in urban runoff across the United States, but are generally higher than those measured at other urban streams in the region (Herrera 1994b; Reinelt and Horner 1990). KCM (1992) also conducted a 48-hour livebox study in -Southgate Creek to evaluate whether water quality in the creek would be toxic to fish. A livebox containing four hatchery rainbow trout was installed in the creek downstream of the culvert under S 133rd Place on June 17, 1991. Base flow at the start of the test was approximately 1 cubic foot per second (cfs), increasing to 8- 10 cfs after 36 hours due to a storm event. The four trout were alive and in good condition at the conclusion of the test. This result in conjunction with the observed presence of other fish (primarily sticklebacks) led the authors of the study to conclude that Southgate Creek can support salmonids if habitat in the stream is improved. BUSINESS INVENTORY There are 48 businesses operating within the Southgate Creek drainage basin that can be considered potential sources of pollution to the storm drain system (see. Figure 4 and Appendix C). The 15 automotive facilities constitute the largest category of businesses operating in the basin. These facilities include new and used car and truck dealerships, auto parts stores, car washes, and auto repair shops (general repair and service stations). Petroleum hydrocarbons, cleaning solutions, and degreasers are the primary contaminants associated with automotive operations. Other businesses operating in the Southgate Creek include a paint manufacturer; a machine shop; an industrial laundry; a drycleaner; a nursery; manufacturers of fabricated metal products, ornamental iron, gaskets and seals, cabinets, and measuring devices; lawn and garden services; and roofing and mechanical contractors. NPDES-Permitted Facilities Currently there are no discharges of industrial wastewater permitted under the National Pollutant Discharge Elimination System (NPDES) in the Southgate Creek basin. However, several facilities have obtained NPDES permits to discharge stormwater. Under the NPDES regulations, stormwater runoff from certain industrial facilities and construction sites larger than 5 acres is subject to NPDES permit requirements. These facilities were required to develop a stormwater pollution prev&ntion plan incorporating applicable best management practices by October 1, 335/plan 10 Herrera Environmental Consultants 1993. Plans were required to be implemented by October 1, 1994. In addition, NPDES- permitted facilities must conduct two annual inspections (one during wet weather and one during dry weather) to verify that the best management practices are adequate. The following three facilities are covered under the baseline NPDES stormwater permit issued by (or) granted to the Washington Department of Ecology (Ecology): • Farwest Paint Manufacturing Company • A & E Machine • Structural Instrumentation, Inc. Contaminated Sites The following three sites in the Southgate Creek basin are included on the Ecology Model Toxics Cleanup Program list of contaminated sites in Washington: • Fostoria Park Industrial Center • American Tire Wholesalers • Structural Instrumentation, Inc. A brief description of each site is provided in the following sections. Fostoria Park Industrial Center The Fostoria Park Industrial Center is a seven -building light -industrial park located on the west side of S 134th Street at S 133rd Street. The industrial park is constructed on earth fill containing industrial waste that is similar in texture to fly ash. A subsurface investigation conducted in the vicinity of the two buildings bordering S 134th Street, determined that the fill material along the eastern portion of the industrial park ranges in thickness from 4 to 14 feet (Earth Consultants 1991). The fill material exhibits elevated pH levels (11.9 to 12.85) and calcium content (32 to 34 percent), as well as other metals including iron, potassium, magnesium, sodium, and sulfur, which are commonly found in cement kiln dust or other similar lime -rich materials. Under the state dangerous waste regulations, any material having a pH level greater than 12.5 is classified as a dangerous waste and must be disposed of at a licensed hazardous waste landfill. Seven monitoring wells were installed at the site in 1989 and 1990 at the locations indicated in Figure 5 (Earth Consultants 1991). The pH values of ground water collected from five of the seven wells (MW -1, MW -2, MW -3, MW -6, and MW -7) range from 11.84 to 12.75, exceeding the state ground water quality standard of 6.5 to 8.5 pH units. Ground water pH in two wells (MW -1 at 12.67 and MW -7 at 12.75) exceeds the criterion of 12.5 for dangerous waste. By comparison, pH in the one well that is screened in native soil (MW -4) was measured at 6.43. In addition, the state Model Toxics Control Act (MTCA) method A cleanup level of 5 µg/L for arsenic and lead was exceeded in two (MW -4 and MW -6) and five (MW -2, MW -3, MW -4, MW - 6, and MW -7) of the wells, respectively. 335/plan 11 Herrera Environmental Consultants As part of this 1991 study, surface water samples were also collected from the ditch that runs along the west side of S 134th Street (east drainage system), and the drainage ditch on S 133rd Street, to determine if contaminants\ present in the fill were affecting surface water quality (Figure 5). Samples were analyzed for pH and metals. The pH data are summarized in Table 5. The highest pH levels (8.5 to 9.7) were measured in the ditches immediately adjacent to the site (stations SW -3, SW -4, SW -5, SW -7, SW -8, and SW -9). Background pH measured in both ditches upstream of the site ranged from about 6.6 to 7.6. Elevated pH (8.45) was also observed in the S 134th Street ditch as far as 250. feet downstream from the site (station SW -11). Metals concentrations in the water samples from the two ditches were generally low, indicating that these materials were not leaching out of the fill and contaminating nearby surface waters. The concentrations of arsenic and lead, the two metals that were elevated in the onsite monitoring wells, were below the state standards for acute and chronic toxicity for aquatic life in all of the surface water samples analyzed. Monitoring wells and surface water at the Fostoria Park Industrial Center were sampled again in 1993 (Martin and Moreno, 1993 personal. comm.). As shown in Table 5, 1993 results are similar to 1990 results, with pH levels elevated in the monitoring wells that are completed in the fill material and in the drainage ditches along the property line. Surface water samples collected at stations SW -1, SW -3, SW -7, and SW -8 were also analyzed for metals. The results indicate that metals are not being ,mobilized from the fill. Metals were undetected in all samples at the following detection limits (µg/L): Antimony 100 Chromium 20 Selenium 150 Arsenic 200 Lead 100 Silver 20 Beryllium 10 Mercury 0.5 Thallium 150 Cadmium 5.0 Nickel 50 Zinc 50 In addition, a soil sample was collected from the southwest side of building E (Figure 5) by hand digging about 2 feet into the fill material. A pH level of 12.3 was measured in the sample. Reported concentrations of the metals antimony (29 mg/kg), arsenic (160 mg/kg), cadmium (7.3 mg/kg), chromium (10 mg/kg), copper (78 mg/kg), lead (2,900 mg/kg), and zinc (1,500 mg/kg) exceeded the MTCA method A or B cleanup levels. However, none of the metals exceeded the threshold for dangerous waste. Therefore, this soil sample is not considered a dangerous waste, and'disposal in a licensed hazardous waste landfill would not be required. American Tire Wholesalers American Tire Wholesalers formerly was located at 4435 S 134th Street in the Fostoria Park Industrial Center. The warehouse building, located in the northwest part of the industrial park, is currently vacant. This site contains the same industrial fill material as described above for the Fostoria Park Industrial Center. 335/plan 12 Herrera Environmental Consultants Structural Instrumentation, Inc. Structural Instrumentation is located at 4611 S 134th Street. A preliminary site assessment conducted in 1990 found petroleum product contamination both in soil on the property, caused by an underground storage tank that is no longer in service, and in surface water, due to discharge from an air compressor that entered a nearby storm drain (Ecology 1990). A water sample collected from a visible stained area on the property contained 173,000 mg/L total oil and grease. Nonhalogenated solvent contamination is also suspected, in the vicinity of a solvent storage area, because extensive staining and breakdown of the asphalt pavement was evident. However, solvent contamination has not been confirmed. HOUSEKEEPING PRACTICES A drive-by reconnaissance was conducted as part of the field activities to evaluate general housekeeping practices employed by local businesses and residents in the Southgate Creek basin. When possible, a brief drive -though of individual sites was conducted to evaluate maintenance practices such as equipment and material storage, waste disposal, and general yard maintenance. Otherwise, observations were made from the street. Photographs were taken to record typical housekeeping practices, and observations were recorded in field notes. In general, many of the local businesses could improve their equipment and material storage practices. Equipment and materials are often stored outdoors without a roof or covering to prevent contact with stormwater. In addition, waste storage areas often have no secondary containment to prevent spills or leaks from entering the local storm drain system. A brief description of specific observations made during the drive-by reconnaissance is provided below: ■ Fostoria Business Park - Outside dumpster with lid open, allowing rainwater to contact waste material and enter nearby storm drain system - Waste roofing materials and other debris stored outdoors. • 4601 S 134th Place: Waste storage drums stored outdoors with no secondary containment; immediately adjacent to catch basin • 4522 S 133rd Street: Waste and paint containers stored outdoors with no secondary containment • 13875 Pacific Highway S (SR -99): Roofing materials and equipment stored outdoors with no covering or secondary containment. Waste disposal practices were difficult to evaluate during the one-time inspections. More frequent inspections and contact with local businesses are needed to better evaluate disposal practices. 335/plan 13 Herrera Environmental Consultants Local residents could also improve their waste handling practices. Many of the ravines are littered with debris (including grass clippings, tires, old furniture, and other refuse). SPILL RECORDS - Accidental spills from commercial or industrial facilities and transportation -related sources represent a potential threat to surface and ground water quality in the Southgate Creek basin. Uncontrolled releases from spills or leaks are often difficult to track because they are not always reported. Consequently, these releases may not be adequately cleaned up, allowing contaminant residues remaining in soil or ground water to act as long-term pollutant sources. The general public often contributes to the problem by improperly disposing of household wastes. Improper disposal of used crankcase oil is probably the best example of how individual practices can create a basinwide water quality problem. Used crankcase oil generated by home automotive maintenance activities is often improperly disposed of in nearby catch basins or is simply dumped on the ground. Although individually these discharges may be insignificant, the cumulative effect from many individual discharges can significantly degrade water quality. Loftness (1981) estimates that 8 million gallons of motor oil are sold each year in Washington state. Earlier studies conducted by the U.S. Environmental Protection Agency (U.S. EPA 1973) and the Oregon Department of Environmental Quality (1978) estimate that 40 to 60 percent of waste oil generated by home automotive repair activities is disposed of improperly (i.e., it is dumped on the ground, poured into storm drains or sanitary sewers, or placed in garbage cans). Recent public education efforts conducted by the King County Department of Metropolitan Services (Metro) and Ecology to encourage recycling of waste oils and other household products have likely improved public waste disposal practices. Ecology also operates a recycling hotline (1 -800 -recycle) to provide information about recycling opportunities. Locally, recycling issues are handled through the Tukwila Department of Community Development, which provides technical assistance to local businesses in setting up recycling programs, and also promotes recycling efforts by local residents through public education and sponsorship of an annual cleanup day for collection of hard -to -recycle domestic materials. A description of Tukwila programs is provided in the chapter on Regulatory Framework under the Existing Programs section. Currently, two oil collection sites located within the Southgate Creek basin accept waste oil from the public free of charge. The facilities, which accept waste oil 5 to 6 days a week, typically 8 hours a day, are located at the BP service stations at 13310 Interurban Avenue S and 14415 Pacific Highway S. Spills that occurred in the Southgate Creek basin between 1991 and 1995 and were reported to Ecology are summarized in Table 6. Most spills are reported to Ecology's regional spill response unit. Since 1990, spill reports received by the northwest regional office, which covers the Tukwila area, have been entered on a computer database. Between 1991 and 1995, 15 spills 335/plan 14 Herrera Environmental Consultants occurring in the Fostoria basin were reported to Ecology. Materials spilled include oil and petroleum products, acids and other corrosive materials, food waste, paint and paint thinner, and sewage. The majority of the spills (nine incidents) involved oil or petroleum products. Quantities spilled were generally less than 30 gallons. However, 10 of the 15 spills discharged directly to nearby surface waters, thus contributing to water pollution in the Fostoria basin. More important, most of the reported spills were not accidental (i.e., they did not result from causes such as automobile accidents or leaking underground storage tanks), but rather were caused by illegal dumping or improper waste storage practices. Future spills of this nature can be prevented if local businesses and residents improve their waste handling and disposal practices. 335/plan 15 Herrera Environmental Consultants 335/plan 16 Herrera Environmental Consultants STORMWATER QUALITY AND POLLUTANT SOURCE CHARACTERIZATION STORM DRAIN SAMPLING PROGRAM The storm drain sampling program conducted as part of this study was designed to characterize existing water quality conditions in the Southgate Creek basin, identify pollutants of greatest concern, and isolate the locations of major contaminant sources. The sampling program involved collecting water samples at six locations in the Southgate Creek basin on three separate occasions (Herrera 1994a). Sampling Stations and Events Samples were collected during conditions of summer base flow (September .19, 1994), winter base flow (January 27, 1995), and winter storm flow (March 8, 1995). Total rainfall measured at the Seattle -Tacoma International Airport during the winter storm flow event was approximately 0.58 inches. The locations of the six sampling stations are described below and illustrated in Figure 6. 335/plan Station 1. North/middle fork of Southgate Creek upstream of the convergence with the south fork. Station 2. South fork of Southgate Creek upstream of the convergence with the north/middle fork. Station 3. Central drain approximately 250 feet downstream of S 135th Street. Station 4. East drain at the intersection of S 133rd and S 134th streets. Station 5. Southgate Creek near discharge to the Duwamish River. (During the summer base flow monitoring, samples were collected from Southgate Creek downstream of Interurban Avenue S and immediately upstream of the discharge into the Duwamish River. During the winter base flow and storm flow monitoring events, samples were collected from two stations (5A and 5B) and composited. Station 5A is located at the mouth of the culvert under 42nd Avenue S near S 134th Street. Station 5B is located at a manhole on the bypass at S 133rd and S 134th streets. Station 6. Ditch located behind the commercial park on the east side of S 134th Street at S 133rd Street. 17 Herrera Environmental Consultants Sampling Methods Summer and winter base flow samples were collected as single grab samples after an antecedent dry period of at least 60 hours. The summer base flow samples, collected near the end of the summer dry season, can be used to characterize ground water contributions and to assess possible illicit discharges to the drainage system (e.g., sanitary sewer cross -connections). Winter base flow samples represent baseline conditions occurring between' rainfall events during the wet season, when shallow ground water/interflow rather than surface runoff constitutes the major source of flow in the creek. Because the wet season in western Washington generally lasts from November through April, these samples represent the water quality conditions that aquatic organisms in Southgate Creek are exposed to for a large part of the year. Winter storm flow samples were composited from individual grab samples collected every 40 minutes for a period of 3 hours during the storm event (a total of four grab samples were collected at each station). The flow rate at each station was measured at the time the grab sample was collected. At the end of the 3 -hour sampling event, a single flow rate composite sample was prepared at each, sampling station. Base flow and storm flow samples were analyzed for the following constituents typically found in urban runoff: • Conventional parameters (temperature, pH, dissolved oxygen, turbidity, hardness, and total suspended solids) • Nutrients (total phosphorus and soluble reactive phosphorus) • Fecal coliform bacteria • Total petroleum hydrocarbons • Metals (dissolved copper, lead, and zinc in base flow samples; dissolved and total copper, lead, and zinc in storm flow samples). RESULTS Comparison to State Water Quality Standards Applicable state water quality standards for Class A freshwaters are summarized in Table 7. Results for the summer base flow samples presented in Table 8 exceed state standards for pH, dissolved oxygen, and fecal coliform bacteria at several of the sampling stations. For example, pH values at stations 1, 3, and 6 are below the acceptable range of 6.5 to 8.5 pH units, while at station 4 (8.63), the pH value is above the acceptable range. However, the pH level measured in Southgate Creek near the outfall into the Duwamish River (station 5) is within the acceptable range. Dissolved oxygen concentrations at station 4 (7.0 mg/L) and station 6 (3.8 mg/L) are 335/plan 18 Herrera Environmental Consultants below the state standard of 8.0 mg/L. In addition, the fecal coliform bacteria counts at all six stations exceed the state standard (<100 cfu/100 mL). Temperature values at these six sampling stations meet the water quality standard. Turbidity levels in all samples are low, generally less than 3 nephelometric turbidity units (NTU), except at station 6 which measured 8 NTU. The slightly higher turbidity at Station 6 was probably introduced by sampling procedures. Flow at station 6 during the summer base flow sampling event was very low (only about 2 inches deep), which made it difficult to fill the sample bottles without disturbing the bottom sediments. Dissolved metals concentrations (copper, lead, and zinc) are all well below the state standard for both chronic and acute toxicity to aquatic organisms. Results for the winter base flow samples are presented in Table 9. The pH measurement at station 4 (9.23) is above the acceptable range of 6.5 to 8.5 units. The dissolved oxygen concentration at station 6 (6.4 mg/L) is below the state standard (minimum of 8.0 mg/L). Fecal coliform bacteria numbers at stations 1, 3, 4, and 5 exceed the state standard (geometric means <100 cfu/100 mL, with no more than 10 percent of the samples exceeding 200 cfu/100 mL). Temperature at all stations meets the water quality standard.. Assuming that the summer base flow samples represent baseline conditions for turbidity, the turbidity levels measured in the winter base flow samples are all within 5 NTU of the baseline levels, as required by the state water quality standards. Dissolved metals concentrations are all well below the state standards for both chronic and acute toxicity to aquatic organisms. Results for the winter storm flow samples are presented in Table 10. The pH levels at station 4 (8.98) and station 5A (8.93) exceed the maximum allowable level of 8.5 units. Fecal coliform bacteria numbers at stations 1 through 5 (1,800 to 7,000 cfu/100 mL) exceed the Class A standard of <100 cfu/100 mL; only station 6 (22 cfu/100 mL) exhibits acceptable levels of fecal coliform bacteria. Dissolved oxygen concentrations meet the state standard (8.0 mg/L minimum) at all stations except station 6 (7.85 mg/L). Dissolved metals concentrations are all well below the state standards for both chronic and acute toxicity to aquatic organisms. Temperature values are within the acceptable range in all samples. In general, turbidity and total suspended solids concentrations are higher in the storm flow samples than in the base flow samples. The turbidity at all six sampling stations under storm flow conditions is greater than 5 NTU above the measured base flow conditions (as defined by the summer base flow samples). These results are consistent with field observations of serious channel erosion and subsequent sediment transport occurring in many streams within the Fostoria basin. Dissolved Versus Total Metals Concentrations in Winter Storm Flow Samples Comparison of the dissolved and total metals concentrations shows that lead is present primarily in particulate form (dissolved lead was undetected at 1 µg/L in all storm flow samples), while between 27 and 45 percent of the copper is in dissolved form, and about 6 to 28 percent of the zinc is in dissolved form. Dissolved metals are more readily absorbed by aquatic organisms than are particulate -bound metals. Therefore, the dissolved form is more important in assessing possible impacts on aquatic life. Dissolved metals concentrations (for copper, lead, and zinc) are all well below the state water quality standards for acute and chronic toxicity to aquatic life. 335/plan 19 Herrera Environmental Consultants Based on these results, it appears that metals do not represent a problem for aquatic life in the Fostoria basin. Comparison of Results from the Three Sampling Events Results for selected parameters from each of the three sampling events are compared and evaluated in this section. At all six stations, the storm flow rates are significantly higher than the base flow rates (Figure 7). As described earlier, the Fostoria basin has no regional detention facilities and only limited private detention facilities. As a result, runoff from most developed areas in the basin is not controlled, discharging directly to the drainage system. The south fork, east drain, and outfall stations exhibit the greatest difference between storm flow and base flow (approximately one order of magnitude), while in the north/middle fork, central ditch, and S 134th Street ditch, storm flow is only about 4 times greater than base flow. Total rainfall for the March 8, 1995 storm event, measured at Seattle -Tacoma International Airport, was about 0.58 inches, which represents about a 1 -month, 24-hour event (Ecology 1992). Thus, flows during larger storm events will be considerably larger than those measured as part of this project. The pH data are summarized in Figure 8. In general, pH results fall within the acceptable range for Class A waters, with only two exceptions. The first occurs during summer base flow, where pH measurements are below the allowable minimum of 6.5 pH units at the north/middle fork, (station 1) the central drain (station 3), and the drainage ditch behind the industrial park on the east side of S 134th Street. Low pH levels at these stations are most likely caused by organic acids (station 6) generated by decaying vegetation. Summer flows at these stations are very low (less than 30 gallons per minute), and the stream and ditch channels at these stations are overgrown with vegetation. The most notable excursion in pH values occurs in the east drain, where the results for all three sampling events (8.63 to 9.23 pH units) exceed the maximum allowable pH value for Class A waters of 8.5 pH units. The east drain sampling station is located at the intersection of S 134th Street and S 133rd Street, directly opposite the Fostoria Park Industrial Center. Elevated pH levels in the ditch are caused by industrial waste used as fill material at the industrial center. A recent investigation of subsurface soil and ground water at the industrial center (Earth Consultants 1991) found that the site is underlain by a fine-grained industrial waste material (probably lime kiln dust) at depths of zero to 15 feet. The fill material exhibits elevated pH levels (11.9 to 12.85 units) and also contains some metals (iron, potassium, magnesium, sodium, and sulfur). Dissolved oxygen data are summarized in Figure 9. With the exception of the summer base flow samples collected from the central ditch (station 3) and from the drainage ditch behind the industrial park on the east side of S 134th Street (station 6), dissolved oxygen concentrations are within the acceptable range specified under the state standards for Class A waters. Station 3 is located in an open ditch that runs along the west side of S 134th Street. The road right-of-way and the parking lot for the Fostoria Park Industrial Center along this reach extend almost to the edge of the ditch. Riparian vegetation consists primarily of reed canarygrass; bushes and trees have been removed. As a result, this section of the ditch is poorly shaded and subject to solar 335/plan 20 Herrera Environmental Consultants heating. In addition, the channel gradient is almost flat, which allows little opportunity for reaeration. Similar conditions exist in the ditch at station 6, which is located in a shallow ravine .that is overgrown with weeds, blackberry bushes, and small trees. During the summer base flow sampling event, flow in the ditch was extremely low, consisting of shallow flow spreading as sheet flow across the bottom of the ditch. This shallow flow (which increases the contact with soil and enhances .warming), combined with very low flow velocities is the cause of the low dissolved oxygen concentration at station 6. Fecal coliform bacteria data are summarized in Figure 10. Most of the samples collected from Southgate Creek exceed the state standard for Class A waters (i.e., geometric mean < 100 cfu/100 mL and not more than 10 percent of all samples exceeding 200 cfu/100 mL). Elevated numbers of fecal coliform bacteria are common in urban runoff. A recent study conducted in the Pipers Creek watershed in north Seattle found that fecal contamination in stormwater runoff was contributed entirely from animal sources (i.e., dog, cat, and bird) rather than human sources (Herrera 1993). The presence of elevated fecal coliform bacteria concentrations in the base flow samples, particularly in summer base flow when there is little if any contribution from surface runoff, suggests that there may be other sources of fecal contamination present in the watershed. Other likely sources include failing septic tanks that contaminate local ground water, sanitary sewer leaks that infiltrate into the storm drain system, and cross -connections between the sanitary and storm sewer systems. Most of the Southgate Creek basin is served by sanitary sewer, and most of the basin is within the Val Vue Sewer District; only the eastern portion along Interurban Avenue S is in the city of Tukwila service area. Although residents are not typically required to connect to the system when a new sewer line is installed, they are charged for service by the local sewer district regardless of whether they connect to the sewer. Therefore, it is likely that most residences and businesses located in sewered areas within the Fostoria basin are connected to the sewer. Remaining unsewered areas within the basin are located primarily along Military Road S. Seattle/King County Department of Public Health records indicate that many septic tank failures have occurred throughout the basin (Figure 11): Given the age of most of the residential development in the basin (40 to 50 years), it is possible that some of the existing sanitary sewer pipes may need repair or replacement. The high fecal coliform bacteria numbers observed in the summer base flow sample collected in the ditch behind the light industrial center on the east side of S 134th Street (station 6) have not been confirmed. This summer base flow result appears to be inconsistent with the winter base flow and storm flow samples, which contain very low fecal coliform counts (14 and 22 cfu/100 mL, respectively). Given the shallow flow conditions encountered during the summer base flow event, it is possible that this sample was inadvertently contaminated during sampling operations. Therefore, it is recommended that additional base flow samples be collected at station 6 to confirm whether fecal coliform bacteria numbers are elevated. The results for dissolved copper are summarized in Figure 12. State water quality standards for metals are based on the dissolved fraction, because dissolved metals are more available for uptake by aquatic organisms. Dissolved.copper was undetected (at a detection limit of 1 µg/L) in all of the base flow (summer and winter) samples. Although copper was detected in the winter 335/plan 21 Herrera Environmental Consultants storm flow samples, the concentrations, which range from 1.8 to 3.7 µg/L, are well below the state standards for acute (10-12 µg/L) and chronic (7-8 µg/L) toxicity to aquatic organisms. (Note: State water quality standards for copper are determined based on hardness. The stated ranges represent the variability in water hardness measured in the Southgate Creek samples.) ' Dissolved lead results are summarized in Figure 13. Dissolved lead was detected in only one sample, the winter base flow sample from station 5 located near the outfall to the Duwamish River. The concentration measured in this sample (0.9 µg/L) is below both the acute and chronic toxicity criteria for aquatic organisms. Dissolved zinc results are summarized in Figure 14. None of the samples exceed the state standards for acute and chronic toxicity to aquatic organisms. The highest concentration (56 µg/L) was measured at the outfall station during winter base flow conditions. Because the lower section of Southgate Creek was tidally influenced by the Duwamish River when the winter base flow 'samples were collected, the sample for this station was composited from two samples collected from the bypass on S 133rd Street and from the downstream end of the 48 -inch culvert under 42nd Avenue S and S 134th Street. Given the relatively low flow in the 48 -inch culvert (0.2 cfs) during the winter base flow event, the elevated zinc concentrations may have been caused by contributions from the galvanized corrugated metal pipe at this station. Dissolved zinc concentrations at station 6, in the drainage ditch behind the light industrial park located on the east side of S 134th Street, were also higher than most of the other stations in the basin, particularly during the winter base flow (28 µg/L) and winter storm flow (32 µg/L) sampling events. Station 6 receives runoff primarily from the light industrial park west of S 134th Street. One of the larger businesses in this park is a mechanical system contractor who stores large amounts of ventilation ducting and piping (primarily galvanized piping) outdoors in its yard. This material may contribute to the elevated zinc concentrations observed at this station. Comparison with Runoff Data from Other Urban Areas Table 11 compares water quality sampling results for the Southgate Creek basin with available data from other urban areas in the Puget Sound region. Total suspended solids, total phosphorus, and metals concentrations measured in samples from the Southgate Creek basin are well within the range of concentrations, and in most cases are on the low end of the range measured in other urban areas. However, the fecal coliform bacteria levels tend to be at the high end of the range measured in other urban areas (from 12 to 3,215 cfu/100 mL), particularly at station 5 in Southgate Creek near the outfall to the Duwamish River, where fecal coliform bacteria numbers range from 180 to 7,000 cfu/100 mL). In addition, the geometric mean concentrations measured at station 1 (1,500 cfu/100 mL), station 3 (1,500 cfu/100 mL), and station 5 (1,300 cfu/100 mL) are about 5 to 7 times greater than the concentrations measured in other urban areas, which reflects the higher concentrations measured in base flow samples collected from these stations in Southgate Creek. 335/plan 22 Herrera Environmental Consultants REGULATORY FRAMEWORK To be effective, the Fostoria Basin Stormwater Management Plan must be consistent with existing stormwater regulations. A number of local, state, and federal regulations and ordinances that address stormwater issues are already in place. These regulations provide the framework under which the Fostoria plan has been developed. This section briefly summarizes the existing regulations and ordinances that pertain to stormwater management. STORMWATER REGULATIONS Puget Sound Water Quality Management Plan The Puget Sound Water Quality Management Plan (Puget Sound Water Quality Authority 1986, 1991) provides a framework for stormwater management in the Puget Sound area and also establishes Ecology as the technical lead responsible for developing guidance on stormwater issues for local jurisdictions. The stated goal of the plan is "to protect and restore beneficial uses of aquatic resources, including shellfish beds, fish habitat, and other resources, to prevent the contamination of sediments from urban runoff, and to achieve standards for water and sediment quality by reducing as necessary pollutant discharges from stormwater throughout Puget Sound. " Under the plan, all cities and counties in Puget Sound are required to adopt ordinances that allow them to establish the following programs: • Stormwater quality controls for all new development and redevelopment projects • An operation and maintenance program for all public and private stormwater facilities. These program elements are intended to prevent increases in stormwater pollution. Ecology has prepared a guidance manual that establishes minimum requirements for stormwater controls, the Stormwater Management Manual for the Puget Sound Basin (referred to as the technical manual) (Ecology 1992a). Local stormwater control programs must be consistent with the Ecology technical manual. In addition to the basic program, densely populated urban areas are required to develop a comprehensive urban stormwater program. Although this requirement initially covers only the six largest cities and four largest counties in the region, by the year 2000 all urban areas including Tukwila will be required to implement a comprehensive urban stormwater program. The program incorporates the following additional requirements: 335/plan 23 Herrera Environmental Consultants ■ A water quality response program to investigate water quality problems and programs in watersheds shared by other jurisdictions • A stormwater public education program that targets local residents, businesses, and industries. A schedule for implementing the comprehensive program must also be developed, with provisions to enable cities to require retrofitting of existing systems if the control measures listed above fail to adequately control stormwater pollution. In addition, cities must demonstrate that adequate funding is available to support the comprehensive stormwater program. National Pollutant Discharge Elimination System In 1990, the U.S. EPA adopted regulations establishing requirements for municipal and industrial stormwater discharges. Large municipalities, defined as those with over 250,000 residents, and medium-sized municipalities, with over 100,000 residents, are required to obtain a NPDES permits for stormwater discharges. Although Tukwila does not currently fall under these requirements, the city will be required to comply with the next phase of the program, which the U.S. EPA plans to establish for smaller municipalities (or, if the population of Tukwila, currently at 14,750, ever exceeds the 100,000 threshold, the city will be required to apply for an NPDES ' stormwater permit). The NPDES municipal permit program has been developed concurrently with the Puget Sound Water Quality Management Plan; consequently, the two programs are not in conflict and in many ways are complementary. Both programs require the use of best management practices to achieve water quality program objectives. The NPDES program additionally requires sample collection for the evaluation of pollutant discharges and a screening mechanism to identify illegal discharges. ' The NPDES program also requires certain industries (including 11 industrial categories defined by standard industrial classification), and construction sites greater than 5 acres, to obtain NPDES permits. The city maintenance shop (located outside the Fostoria basin) is required to obtain an NPDES stormwater permit. In addition, the city is required to obtain a permit for any city construction project that disturbs more than 5 acres. ' Both the municipal and industrial NPDES stormwater programs are administered by Ecology. As stated earlier, Tukwila is not currently covered by the NPDES municipal stormwater program. However, when the NPDES permit program is expanded to cover small municipalities like Tukwila, the city must implement a program to comply with the NPDES requirements, which will entail becoming proactive in dealing with local industries that may discharge ' 335/plan 24 Herrera Environmental Consultants industrial stormwater to the city storm drain system. Therefore, it would be advantageous for the city to anticipate these pending regulations by establishing stormwater and nonpoint source controls. The Fostoria Basin Stormwater Quality Management Plan represents an important first step in achieving the goals of the NPDES program. State Growth Management Act The Washington Growth Management Act requires that jurisdictions prepare a comprehensive plan to establish guidelines for future development (RCW 36-70A). Included in the plan is a land use element that provides "guidance for corrective actions to mitigate or cleanse those discharges that pollute waters of the state, including Puget Sound or waters entering Puget Sound." Tukwila prepared a Surface Water Management Comprehensive Plan in April 1993 for the entire city, which is described briefly in the following section. To be consistent with the state Growth Management Act, the goals of the city comprehensive plan should be similar to the basic stormwater program requirements under the Puget Sound Water Quality Management Plan. To this end, the city of Tukwila has prepared a draft surface water ordinance that is currently under review. EXISTING TUKWILA STORMWATER QUALITY AND POLLUTANT CONTROL PROGRAMS 1993 Surface Water Management Comprehensive Plan The Surface Water Management Comprehensive Plan, adopted in 1993, builds upon the stormwater program established when the Storm and Surface Water Utility was formed in 1989. The comprehensive plan was prepared to meet upcoming state and federal regulations regarding stormwater. The objectives of the plan are listed below: 335/plan Enhance and maintain water quality in the Green/Duwamish River and its tributaries to support beneficial uses • Coordinate plans, systems, and policies of the program with those of other jurisdictions and governmental agencies within the Green River Management Agreement area ■ Provide for the long-term storm drainage control needs of the city • Protect the physical and biological integrity of wetlands, stream corridors, and associated habitats ■ Establish and operate funding mechanisms that equitably allocate costs 25 Herrera Environmental Consultants • Encourage the development of regulations that are consistent, predictable, and equitable • Build public understanding of surface water management problems as well as responsibilities and opportunities for individuals to improve water quality and drainage • Emphasize the use of natural systems and nonstructural methods that focus on preventing and controlling runoff and pollution at the source • Develop, implement, and maintain a comprehensive program to manage surface water in the city. Included in the comprehensive plan are a series of capital improvement projects that have been developed to address existing and future problem areas in the city. Three projects are identified for the Southgate Creek: • A ditch and culvert improvement project involves enlarging the ditch that runs along the west side of S 134th Street from 48th Avenue S to S 133rd Street and replacing existing culverts under driveways. • A channel stabilization project on Southgate Creek between 40th Avenue S and 42nd Avenue S includes cleaning and enlarging the stream channel between 40th Avenue S and S 133rd Street, enlarging the channel and installing riprap between S 133rd Street and S 133rd Place, installing a sediment trap at the entrance to the culvert under S 133rd Street, and replacing the existing culvert under S 133rd Place. • A bypass pipeline and channel improvement project on Southgate Creek is intended to divert peak flows from the east drain and the north, middle, and south forks of Southgate Creek directly to the outlet channel located near the Allentown bridge on Interurban Avenue S. The project includes constructing a diversion structure at S 133rd and S 134th Streets, constructing a 42 -inch diversion pipe along S 133rd Street from the diversion structure to 42nd Avenue S, and installing a 66 -inch and 4 -foot by 8 -foot box section bypass pipe along S 133rd Street and Interurban Avenue S. To date, only the bypass pipeline project on Southgate Creek has been constructed. , The project was modified by increasing the bypass pipe diameter to 72 inches. In addition, a stub for the 42 - inch diversion pipe on S 133rd Street was constructed, but the pipe was not extended up S 133rd Street. Stabilization work has been completed in Southgate Creek. However, the work occurred upstream of 40th Avenue S. In addition to the capital improvement projects, the 1993 stormwater comprehensive plan identifies several opportunities to restore fish habitat in city creeks. One project located in Southgate Creek involves restoring fish habitat downstream of 42nd Avenue S, as well as 335/plan 26 Herrera Environmental Consultants stabilizing the creek banks upstream of 42nd Avenue S and installing a sedimentation basin to enhance stream habitat and reduce erosion. This project was carried through preliminary design (KCM 1993) but has not yet been constructed. Draft Tukwila Comprehensive Plan Tukwila is in the process of preparing a comprehensive plan that establishes goals and policies to guide future decisions regarding urban growth in the city. Surface water management is included in the 1995 draft comprehensive plan as one of the utilities needed to support future growth. The two primary goals identified for managing surface water are 1) to provide service to Tukwila businesses and residents and 2) to establish capital improvement, maintenance, education, and enforcement programs, as necessary to provide this service. Policies identified to guide the development of the surface water utility that deal with storm and surface water quality concerns are listed below: • Mitigate impacts to wetlands and watercourses from future development • Develop permanent, low maintenance flood controls that incorporate water supply storage, water quality, recreation, and fisheries protection objectives • Develop a signage program to identify important surface water features. Local Ordinances Surface Water Management Ordinance The surface water management ordinance, adopted in December 1995, establishes standards for drainage design, requirements for drainage plan review, permit requirements for storm drainage activities, provisions for critical drainage areas, maintenance requirements for public and private storm drain systems, requirements for water quality analysis, and requirements for performance bonds and securities on construction projects. Provisions that specifically address stormwater quality management include: 335/plan • Adoption of the King County (1990) Surface Water Design Manual as the basis for Tukwila drainage design standards: Under the King County design manual, all new and redevelopment projects that create more than 5,000 square feet of new impervious surface are required to install stormwater quality controls. In addition, the ordinance specifically requires that all storm drainage activities, regardless of size, include controls designed to maintain or enhance water quality. • Requirements for special water quality analysis: The water quality analysis provision allows the city to require that baseline water quality data be collected in support of proposed drainage projects, to evaluate the effects of 27 Herrera Environmental Consultants onsite mitigation improvements and potential effects on water quality downstream of the site. • Maintenance requirements for public and private systems: The ordinance establishes specific schedules for inspecting and maintaining both public and private storm drain systems. In addition, it requires operators of new and existing private systems to monitor and maintain these systems on a specified schedule, as well as to provide access to the system by the city Public Works Department. The ordinance also enables Public Works to complete required maintenance on private systems if the operator fails to do so and to bill the owner for the costs of maintaining the system. Sensitive Areas Ordinance, #1599, #1608 The sensitive areas ordinance establishes requirements for activities affecting wetlands, watercourses, areas of potential geologic instability, abandoned coal mines, and archaeologically significant areas. Specifically, setbacks, buffers, and mitigation,requirements are established for each type of sensitive area. With regard to watercourses, buffer widths are established based on a watercourse rating system. Land -altering activities are restricted to areas outside the buffer zone. Watercourses are rated based on existing habitat functions by assessing instream characteristics (i.e., channel width, channel capacity, channel stability, and fish habitat) and stream corridor quality (i.e., width of unmaintained vegetation, vegetation diversity, corridor barrier function, and surrounding land use). Individual sections of stream are scored for each element and then assigned a rating ranging from 1 (highest habitat value) to 3 (lowest habitat value). Most streams within the Southgate Creek basin are classified as type 3 watercourses (Table 1 and Figure 2). Listed below are the only two stream reaches in the basin that are classified as type 1 watercourses (Jones and Stokes 1990): • Upper section of the east drain located between Macadam Road S and S 136th Street • Central drain between S 137th Street and S 135th Street. In addition, stream reaches covering portions of Southgate Creek, the central drain, the south fork, and the north fork are classified as type 2 watercourses. Required buffer widths for watercourse classifications are summarized below: 335/plan • Type 1 watercourse requires 70 -foot buffer width • Type 2 watercourse requires 35 -foot buffer width • Type 3 watercourse requires 15 -foot buffer width. 28 Herrera Environmental Consultants A similar system is developed to protect wetlands. Wetlands are classified according to the U.S. ' Fish and Wildlife Service system (Cowardin et al. 1979). Required buffer widths for wetland classifications are summarized below: ' ■ Type 1 wetland requires 100 -foot buffer width ■ Type 2 wetland requires 50 -foot buffer width ■ Type 3 wetland requires 25 -foot buffer width. Dredging digging within a watercourse such as would be conducted by the maintenance g g or ggg department for drainage system cleaning operations is permitted under the ordinance, but requires approval by the Director of the Department of Community Development. Scheduling and performance of cleaning operations within watercourses must be arranged to minimize the impacts on water quality. In addition, after work is completed, the affected area must be graded, ' replanted, and maintained to ensure that restoration is successful. ' Diversion or relocation of a watercourse also requires approval by the Department of Community Development. In addition, a plan for mitigating impacts caused by the diversion must be prepared and approved by the department. Relocation of a watercourse shown to have critical ' wildlife or aquatic habitat is not allowed unless the habitat will be improved. Mitigation requirements described in the ordinance include maintaining or enhancing the original aquatic habitat, replanting with native species, restoring stream bank and buffer conditions, maintaining ' or improving stream channel and biofiltration systems, preparing construction documents, and implementing a monitoring plan to evaluate the success of the project. Floodplain Management Ordinance, #1462, #1499 The floodplain management ordinance establish requirements for construction within or near a flood zone and for relocating watercourses. Relocation of a watercourse requires approval by Ecology and the Federal Emergency Management Agency (FEMA). In addition, the ordinances ' require that altered or relocated stream channels be maintained to preserve flow -carrying capacity. Land -altering Activities Ordinance, #1591 The land -altering activities ordinance is a comprehensive program that regulates land -altering ' activities to prevent damage to public and private property (including stormwater systems) by controlling erosion and sedimentation, both during and after project construction. The ordinance also protects water quality by reducing sediment -related pollution of surface water systems. Regulated activities include any operation that changes the natural cover or topography, including land clearing and grading, creation of impervious surfaces, excavation and fill projects, and material stockpiling. The ordinance establishes a permit program for construction projects, including required preparation of a land -altering plan. The plan describes the proposed activity, ' identifies the erosion and sedimentation control practices that will be implemented to reduce erosion during construction, and establishes a monitoring and maintenance program to ensure 335/plan 29 Herrera Environmental Consultants that these systems function as designed. Temporary erosion and sedimentation controls are required to be designed in accordance with the King County (1990) Surface Water Design Manual. The land -altering plan may also be required to describe permanent erosion and sedimentation controls, including sediment and oil retention devices, surface runoff and erosion control devices, and vegetative measures used for erosion control. In addition, a monitoring and maintenance schedule that extends through the life of each system element must be developed and implemented for all permanent facilities. Ongoing Tukwila Pollution Control Activities Storm and Surface Water Utility The Storm and Surface Water Utility was established by ordinance in 1989 to operate and maintain the city storm drainage system. The ordinance establishes a storm and surface water utility fund to be financed through service charges applied to local residents and businesses. The fund is used to repair, maintain, and improve the existing drainage system and to purchase land or easements for the construction of regional stormwater facilities, as well as to support monitoring, inspection, enforcement, and administration activities necessary to implement city surface water policies. The Utility also conducts investigations to evaluate drainage conditions in the Tukwila service area as needed. For example, the city plans to install a permanent monitoring station on Southgate Creek at S 133rd Street and E Marginal Way S to continuously monitor flow in the stream. This information is needed to develop design parameters for instream channel improvements and will also document rainfall runoff relationships in this heavily urbanized stream. In addition, the city intends to install sampling equipment to allow collection of flow- composited samples for stream quality characterization. Equipment costs are estimated at $12,000. Solid and Hazardous. Waste Programs The Tukwila Department of Community Development sponsors a recycling program that indirectly assists in reducing stormwater pollution by encouraging local residents and businesses to recycle and properly dispose of solid and hazardous waste. This program is based on public education and technical assistance efforts that target local residents and businesses. For example, the city recycling program regularly publishes articles in the city newsletter, Hazelnut, which provide information to local residents about household hazardous waste disposal and recycling opportunities. The Hazelnut also .publishes the locations and dates on which the King County hazardous waste mobile collection unit will be in the city to collect household hazardous wastes. In addition, the program routinely provides information to local residents about alternative products that can be used in place of more toxic household products, and also sells compost bins and green cleaning kits to the public at reduced rates. The city also sponsors an annual cleanup event for local residents to dispose of hard -to -recycle items (other than hazardous waste). 335/plan 30 Herrera Environmental Consultants Services for local businesses include publishing a newsletter twice a year to disseminate information on recycling opportunities and appropriate waste disposal practices, and providing technical assistance on how to set up a business recycling program. In addition, the city responds to questions from local businesses about disposal and recycling issues and refers them to local agencies and vendors that supply services in these areas. Fire Department The Tukwila Fire Department is involved indirectly with stormwater pollution control through its fire prevention inspection program. Under this program, the department inspects every business in the city once every 18 months to document compliance with the Uniform Fire Code (Olivas 1995 personal communication). The Uniform Fire Code covers a wide range of activities involving the storage, handling, and dispensing of hazardous and flammable materials. Although the fire department is concerned primarily with safety and fire prevention, its technical assistance efforts cover some issues of concern for stormwater pollution prevention. Topics particularly related to stormwater pollution include secondary containment for storage areas, spill and drainage controls, waste disposal, and employee training. In the course of inspecting hazardous material storage areas, the fire department often works with the city building department to ensure that hazardous material handling and storage areas are designed and constructed in accordance with accepted standards. Because fire department inspectors observe local businesses on a regular basis, they serve as a key point of contact with individual business owners and managers. It is uncertain whether the department would be able or willing to coordinate with the Storm and Surface Water Utility to facilitate evaluation of stormwater pollution control practices. However, because it has the most extensive knowledge of local business operations and housekeeping practices, the fire department represents a significant source of information for the surface water utility. The fire department also staffs the hazardous materials response team. This team responds to spills reported within the city and initiates emergency spill containment. Spill cleanup is generally handled by Ecology. 335/plan 31 Herrera Environmental Consultants 335/plan 32 Herrera Environmental Consultants WATER QUALITY GOALS AND POLICY A set of goals and supporting policy has been developed to guide the preparation of the Fostoria Basin Stormwater Management Plan and future efforts by the City of Tukwila in developing programs to improve stormwater quality in the Southgate Creek drainage basin. These goals have been established to be consistent with local, state, and federal regulations, as well as to address existing and potential future water quality problems in the basin. State and federal policies recognize the ecologic and economic importance of streams and rivers. Existing policies are generally directed toward improving and maintaining the quality of these systems. Comprehensive stormwater quality management, particularly in urbanized areas such as Tukwila, is crucial to the protection of aquatic systems and compliance with state and federal policies. Water quality goals, listed below, have been developed specifically for the Fostoria Basin Stormwater Quality Management Plan in coordination with the citizens action committee: Goal 1: To improve the water quality of Southgate Creek in order to develop and maintain the attributes of a high quality stream and watercourse which is located in an urbanized setting. Goal 2: To establish a stormwater program that complies with the requirements of the Puget Sound Water Quality Management Plan and is consistent with the Clean Water Act requirements for NPDES stormwater permits. Achievement of the above goals is expected to improve stormwater quality and thus protect aquatic resources in Southgate Creek. Specific policies developed to support these goals are summarized below: Policy 1: Develop a basic stormwater program that is consistent with the Puget Sound Water Quality Management Plan and includes the following items: • Design standards for new development (including substantial redevelopment projects as defined in the Ecology technical manual and the King County Surface Water Design Manual) to control stormwater quantity and quality. • An operation and maintenance program for all public and private stormwater facilities to ensure proper operation and function of these facilities. • A surface water management ordinance that establishes methods to maintain and improve water quality in the Southgate Creek watershed. Policy 2: Establish an ongoing water quality capital improvement program (CIP) to improve stormwater quality and protect aquatic resources in Southgate Creek, utilizing funds collected from surface water assessments. In partnership with nearby landowners: 335/plan • Plan and construct stormwater facilities including detention and sedimentation ponds, storm flow separation/bypasses, and other stormwater treatment 33 Herrera Environmental Consultants devices to correct stormwater quantity and associated water quality problems that exist in the basin. • Improve portions of the Southgate Creek channel to reduce undercutting and stabilize the stream channel by removing debris, modifying the existing cross- section (if necessary), installing erosion control material, and planting riparian vegetation. Policy 3: Educate businesses and homeowners through either training programs or brochures on techniques to improve stormwater quality. Also, facilitate the creation of public education programs through local schools or after school programs, senior citizens, or other interested community groups to stimulate stream awareness. (A good educational resource is the Stormwater Management Manual for the Puget Sound Basin [Ecology 1992b], which includes recommended best management practices for residential areas). Policy 4: Develop a community-based water quality project to improve and enhance water quality and aquatic resources in the Southgate Creek drainage basin. 335/plan 34 Herrera Environmental Consultants STORMWATER POLLUTION CONTROL ALTERNATIVES This chapter presents recommended stormwater pollution control alternatives for the Southgate Creek drainage basin. Alternatives have been selected to correct existing and possible future water quality problems, as well as to protect aquatic resources in the streams and drains serving the basin. Two basic types of stormwater controls are recommended: • Programmatic controls (i.e., nonstructural controls) such as best management practices, public education, and technical assistance efforts: The Tukwila Storm and Surface Water Utility would serve as the focal point for implementing these nonstructural controls. A basic stormwater quality program has been devised that could be coordinated by the utility and implemented in a phased approach as funding and staffing become available. • Structural controls that correct specific problems identified in the basin: Structural controls, such as detention ponds or vaults, sedimentation ponds or vaults, diversion and bypass structures, channel improvements (i.e., channel enlargements, stabilization, and revegetation projects) would be constructed under a stormwater quality capital improvement program established by the Storm and Surface Water Utility. A list of recommended capital improvement projects has been developed for the Southgate Creek basin. Programmatic and structural solutions to the existing stormwater quality problems identified in the Southgate Creek basin are presented in the following sections. In addition, a brief summary of existing problems is presented to establish the basis for the stormwater quality control recommendations. SUMMARY OF EXISTING STORMWATER QUALITY PROBLEMS Most water quality problems in Southgate Creek are related to excessive flows generated by urban runoff. Urbanized areas within the basin generally lack adequate stormwater quantity controls. As a result, urban runoff is released at an uncontrolled rate to natural drainage channels. Peak flows to these natural systems have increased dramatically due to urban development. Increased flows have accelerated the naturally occurring erosion along the steep ravines that convey runoff from the upper basin to the lower basin on the valley floor (especially in the south, middle, and north forks of Southgate Creek and the central drain). In some areas, the existing channels have become deeply incised and unstable. In other areas, channel capacity is inadequate to convey the peak flows from larger storm events. In either case, significant quantities of sediment are eroded from the upper basin and deposited in the low-energy areas in the lower basin. Sediment carries with it associated pollutants that are present in urban runoff, such as metals and organic pollutants. Suspended solids also reduce light penetration, which can reduce light levels below the levels needed to sustain photosynthesis in aquatic plants (Jeffries and Mills 1990). In 335/plan 35 Herrera Environmental Consultants addition, erosion and -associated increases in sediment loading alter the aquatic habitat and substrate composition, causing changes in benthic community composition, and potentially smothering macroinvertebrates (i.e., aquatic insects) and juvenile salmonids (Novotny and Chesters 1981). From the perspective of the Storm and Surface Water Utility, increased channel erosion and subsequent sediment deposition in the lower basin have also created maintenance problems as the existing stream channels, ditches, and culverts fill in with accumulated sediments, thus exacerbating flooding problems. Other stormwater quality problems that currently exist in the Southgate Creek basin include: ■ The presence of elevated fecal coliform bacteria counts throughout the basin • Contaminant spills and leaks documented in Ecology spill records, particularly those caused by illegal dumping (incidents involving illegal dumping have also been encountered by the maintenance department and were observed during field reconnaissance efforts conducted as part of this study). Although elevated fecal coliform bacteria counts are common in urban stormwater runoff, the numbers observed in Southgate Creek (1,800 to 7,000 cfu/100 mL in storm flow samples and 50 to 2,300 cfu/100 mL in base flow samples) are generally higher than those reported in other urban areas in the Puget Sound region, where fecal coliform bacteria counts in stormwater runoff from highly urbanized areas range from 42 to 3,215 cfu/100 mL with a geometric mean of about 270 cfu/100 mL (Reinelt and Horner 1990). In addition, the presence of elevated fecal coliform counts in the base flow samples, particularly in summer base flow samples when there is little if any contribution from surface runoff, suggests that there may be other sources of fecal contamination present in the watershed, such as failing septic tanks, leaking sanitary sewers, or sanitary sewer cross -connections. Accidental spills occur in any urban area. However, most of the spills reported to Ecology over the past 5 years in the Southgate Creek basin were not accidental (i.e., caused by automobile accidents or leaking underground storage tanks), but rather were caused by illegal dumping or improper waste storage practices. In addition, during field efforts conducted as part of this study, it was observed that some of the ravines in the basin were littered with debris (e.g., old furniture, tires, yard waste, and other refuse). Although significant degradation of water quality has not been documented in field sampling efforts, these types of problems are often difficult to confirm based on the type of limited sampling conducted as part of this and previous studies in the basin. However, the incidence of spills caused by inappropriate waste disposal or storage activities combined with the field observations indicate that waste disposal practices of local residents and perhaps businesses operating in the basin could be improved. Reduction in the quantity of spills and illegal dumping can only help to improve water quality and quality of stream habitat in the Southgate Creek basin. 335/plan 36 Herrera Environmental Consultants STORMWATER QUALITY PROGRAM This section describes the basic elements of a stormwater quality program that could be implemented by the Storm and Surface Water Utility to aid in improving stormwater quality in Southgate Creek. Stormwater System Mapping It is recommended that inventories and maps of existing stormwater conveyance, detention, and treatment facilities (both public and private) be completed in the Southgate Creek drainage basin. Available information on existing drainage facilities in the basin is limited, particularly regarding private drainage systems. Detailed information about the location (both horizontal and vertical), size, and materials of construction for existing drainage facilities are needed to facilitate future planning and design projects and to support maintenance efforts. The maintenance department is currently responsible for maintaining city -owned drainage systems. Detailed system maps would help maintenance crews to locate structures in need of repair and would aid the department in tracking problem drains. In addition, under the draft surface water management ordinance, scheduled to be adopted in early 1996, owners of private storm drainage systems will be required to inspect, maintain, and monitor their systems to ensure proper operation. To effectively oversee these efforts, the utility will need to know the locations of private facilities and identify their owners or operators. The city has inventoried and mapped other basins within its service area but has not yet initiated mapping efforts in the Southgate Creek basin. Inventorying and mapping were conducted by a summer intern skilled in Autocad. It is recommended that a similar program covering both public and privately owned drainage systems be conducted in the Southgate Creek basin. Enforcement Program to Support Surface Water Management Ordinance Under the draft surface water management ordinance, owners of new and existing private storm drainage facilities will soon be required to inspect, maintain, and monitor these facilities on a routine basis. To ensure that the requirements of the ordinance are met, the Storm and Surface Water Utility should develop a program to oversee these private drainage systems. The inventory and mapping program described above represents a first step in developing an enforcement program. In addition, the utility should implement a record-keeping system and inspection program to aid in tracking these private systems. With improved oversight, the utility will be capable of providing better technical assistance to the operators of private systems and can encourage them to implement appropriate best management practices. Catch Basin Cleaning Storm drain catch basins in the Southgate Creek basin are cleaned about once every 3 to 5 years. Increasing the cleaning frequency to once every year or two to remove accumulated sediment and 335/plan 37 Herrera Environmental Consultants The presence of elevated numbers of fecal coliform bacteria in summer base flow samples collected as part of the pollutant source characterization efforts indicates that domestic wastewater may be entering the storm drain system in the Southgate Creek basin. With the exception of the drainage ditch located behind the industrial park on the east side of S 134th Street (station 6), all sampling stations contained elevated numbers of fecal coliform bacteria ' 335/plan 38 Herrera Environmental Consultants ' (i.e., greater than 200 cfull 00 mL). Possible sources of fecal contamination include inadvertent sanitary sewer cross connections and infiltration of wastewater from leaking sanitary sewers and failing septic systems. The Seattle/King County Department of Public Health has discovered a number of septic system failures in the Southgate Creek basin which may be contributing to the elevated fecal coliform counts observed in summer and winter base flow samples collected as part of this project. With the exception of an area along Military Road S. between S 135th and S. 144th Street, most of the basin is served by sanitary sewer. However, even in sewered areas, some older residences may continue to utilize septic systems. The city should coordinate with the Val Vue Sewer District to identify areas still served by septic system by reviewing as -built plans and information from field inspections. In addition, the Fostoria Basin Citizens Action Committee has indicated that non-stormwater discharges may be occurring in the basin. For example, residents have noted kerosene and diesel odors in the middle fork of Southgate Creek at 40th Avenue S, which may be contributedfrom spills or illegal dumping. Evidence of possible cross -connections has also been observed in the residential areas along 40th Avenue S (e.g., visible soap suds in the drainage channels), which indicates that wastewater from nearby houses may be discharged to the storm drain system. During large storm events, soap suds have also been observed on Southgate Creek by City and Val Vue Sewer District staff. Therefore, it is recommended that an illicit connection survey be conducted along the SR -99 (Pacific Highway) and S 134th Street commercial/industrial corridors as well as along 40th Avenue S. Illicit connections represent a potentially serious threat to stormwater quality in any urban area. Studies have shown that non-stormwater discharges can contribute the bulk of the pollutant loading in some storm drainage systems (Pitt et al. 1993). Examples of illicit connections include sanitary sewer cross connections, infiltration from improperly functioning septic systems and broken or leaking sanitary sewers, and discharges from commercial and industrial operations (e.g., car wash wastewater, radiator flushing wastewater, improper oil disposal, laundry wastewater). Analysis of fecal coliform bacteria, an indicator species that inhabits the intestinal tract of warm- blooded animals (including humans), can be used to locate sanitary inputs to the storm drain system. Laboratory costs to analyze for these bacteria are approximately $30 per sample. Some utilities have also used reagent kits that measure the concentration of ammonia -nitrogen to locate sanitary sewer connections (Glanton et al. 1992). Reagent kits, while less sensitive and less accurate than laboratory methods, offer the advantage of generating results in the field, thereby reducing the time required to track illicit connections. Surveys in residential areas should be conducted early in the morning when most residents arise and discharges from sanitary cross - connections are greatest. In commercial/industrial areas, surveys should be conducted during normal business hours. An initial survey of the drainage under low, base flow conditions should be conducted to look for evidence of illegal discharges (e.g., the presence of flow where there would not normally be any, elevated temperature, visible evidence such as unusual color, turbidity, or sheens, and unusual odors): Once a contaminant source has been identified or traced to a particular segment of the drainage system, dye tests can then be used to verify the exact location so that cross -connections can be eliminated. 335/plan 39 Herrera Environmental Consultants Drainage Plan Reviews The 1995 surface water management ordinance requires that stormwater controls for new development projects be designed in accordance with the King County Surface Water Design Manual (King County 1990) and meet the minimum design standards of the Stormwater Management Manual for the Puget Sound Basin (Ecology 1992a). The Storm and Surface Water Utility should coordinate drainage plan reviews for new development projects to ensure that they comply with the requirements of the ordinance. Technical Assistance Program for Local Businesses The Tukwila Department of Community Development has initiated a recycling program that provides technical assistance to local businesses. The program, staffed by a part-time employee, publishes a semi-annual newsletter that describes recycling opportunities such as the Industrial Materials Exchange (IMEX) and provides information on waste disposal options. The newsletter also lists the department's phone number so businesses can call with questions about waste disposal and recycling issues. In addition, the program has received a grant to hire a consultant to provide technical assistance in setting up recycling programs and responding to questions from local businesses. It is recommended that the Storm and Surface Water Utility participate in this program to encourage local businesses to implement appropriate best management practices to reduce stormwater pollution. To the extent possible, the utility's technical assistance program should use existing resources and programs that have already been developed in the Puget Sound area to facilitate program implementation. For example, the Local Hazardous Waste Management Program run by the King County Department of Metropolitan Services (Metro) and the Seattle/King County Department of Public Health has available an extensive library of information on best management practices and also staffs four field teams that inspect and advise businesses in King County about appropriate waste management practices and regulatory requirements for small -quantity generators of hazardous waste. The program is intended to assist businesses in implementing proper hazardous waste disposal practices and has no enforcement function. Three of the teams are staffed by Metro personnel: 1) the onsite consultation team, which makes uninvited visits to all businesses in selected geographic areas (usually at the request of the local municipality), 2) the onsite consultation team, which visits businesses at their request, and 3) the response team, which acts on complaints from other agencies or the public. A fourth field team, the audit team, is staffed by the Seattle/King County Department of Public Health. The audit team focuses on high priority businesses, canvassing the county and visiting all businesses of a certain type to provide owners with information about applicable regulations and proper waste handling, reduction, and disposal methods. Metro's survey team focuses on selected geographic areas, visiting all businesses regardless of their type of operation. This team inspects each site to observe the facility's waste handling practices and also to provide information on best management practices and services available to small businesses. One of the objectives of these surveys is to obtain information on general 335/plan 40 Herrera Environmental Consultants housekeeping practices employed by local businesses to determine the educational needs of businesses in King County. The survey teams visit about 1,200 businesses in King County each year. Metro survey teams have visited businesses in Tukwila's central business district and could, upon request visit the businesses in the Fostoria basin. The small quantity generator program is supported by the education and technical assistance group, which provides and distributes brochures, fact sheets, and other materials to local businesses describing regulatory requirements and best management practices for handling hazardous waste. The group performs a range of public relations activities such as issuing press releases, publishing articles in local trade joumals, and participating in local trade shows. The technical assistance group also maintains a list of vendors that dispose of hazardous waste (contact: Gayle Savina at 206/689-3062). A list of publications available from the technical assistance group is provided in Appendix D. The technical assistance group also provides onsite consultation teams to review conditions at businesses and offer advice on regulations, containment, and cleanup. Through the speaker liaison program, it also provides speakers and literature upon request to business groups and associations (contact: Dave Waddell at 206/689-3069). Presentations can be tailored to specific audiences and can be general or technical. Public Education The basin characterization and source identification efforts conducted as part of this study indicate that improper waste disposal and materials/waste storage and handling practices constitute an ongoing problem in the Southgate Creek drainage basin. Public education efforts should target local residents and businesses to encourage them to improve waste handling and disposal practices and to implement appropriate best management practices to reduce stormwater pollution. The Department of Community Development has already initiated a program to encourage recycling among local residents and businesses by publishing information on recycling opportunities in the city's Hazelnut newsletter (published every other month) and in semi-annual 'newsletters that are sent to local .businesses. It is recommended that the Storm and Surface Water Utility work with this existing program to promote its efforts in stormwater management and to encourage residents and businesses to employ appropriate best management practices for controlling stormwater pollution. Recommended topics to be addressed in future publications of the Hazelnut are listed below: 335/plan • Publish the results and recommendations of the Fostoria Stormwater Quality Management Plan, including the statement of goals and policy, which would be applicable to many of the drainage basins in the city's jurisdiction. • Summarize city policies and programs that pertain to stormwater management (e.g., draft stormwater management ordinance, sensitive areas ordinance). 41 Herrera Environmental Consultants • Encourage residents to recycle waste oil by publishing the locations of oil collection centers in the area. Presently, there are two collection centers located in the Fostoria drainage basin (the two BP gas stations located on Interurban Avenue S and Pacific Highway) that accept waste oil from local residents free of charge. • Provide information on the care and maintenance of septic tanks, as well as how to identify signs of a failing system (and what to do about it). In addition, a list of septic tank cleaning services in the area and available information sources could also be included in the article. The Seattle/King County Department of Public Health has pertinent information on septic systems that could be used as the basis for an information article. • Provide information on less toxic alternatives for household cleaning products and appropriate methods of disposing household hazardous waste. The Department of Community Development currently distributes green cleaning cards which describe alternative cleaning products and also sells compost bins and green cleaning kits to local residents at very reduced rates. In addition, Metro's outreach and education program has developed other informational brochures that could be used to develop regular articles in the Hazelnut newsletter, including an informational brochure on environmentally safe cleaning products, homebuyer's guide on the use of chemicals in construction, brochures on eliminating chemical usage in residential gardens and appropriate methods of disposing waste paint. Other local newsletters such as the Foster Community News and the Duwamish Improvement Club's newsletter could also be used to disseminate information about stormwater issues to the local community. Community -Based Projects In addition to disseminating information about stormwater management practices, the Storm and Surface Water Utility could organize and implement a community-based project to encourage community participation in the city's stormwater management program. Recommended projects are listed below: 335/plan • Coordinate a volunteer storm drain stenciling program through local schools, boy/girl scouts, or other civic organizations. Because much of the Southgate Creek basin is served by open ditches, this program should also include installing signs along the major drainage courses as well as in Southgate Park to identify stream corridors and to encourage local residents to appropriately dispose of household wastes. Coordinate a stream cleanup project. Many of the ravines in the basin have been used by local residents to dump unwanted household items (furniture, 42 Herrera Environmental Consultants tires, and garbage). This material can be a source of water pollution and also damages the natural habitat. A weekend cleanup project targeting the major dump areas could be coordinated through local civic organizations. CAPITAL IMPROVEMENT PROJECTS Because many of the water quality problems identified in Southgate Creek are flow-related, caused by development that occurred in the past, for which no stormwater controls were constructed, a series of capital improvement projects (CIPs) are also included in the Fostoria Basin Stormwater Quality Management Plan. CIPs, consisting of a variety of structural improvements such as detention/sedimentation ponds and/or vaults, stream channel stabilization, and high flow bypasses, have been identified to correct existing problems in the basin. Because most of the basin is already developed, the recommended CIPs consist of modifications to the existing drainage system (i.e., retrofits), where feasible, to reduce peak runoff rates and subsequent erosion damage to the natural drainages. Recommended structural improvements will need to be incorporated into the utility's overall capital improvement program and constructed as funding allows. This section describes alternatives for improving stormwater quality and identifies areas where additional work is needed to evaluate options. Prioritization of improvements and recommended phasing are described in the following section. Stormwater quality improvements are divided into two categories: incorporation of water quality features into ongoing CIPs, and development of specific stormwater quality improvements in the Fostoria basin. Coordination with Existing CIPs It is first recommended that the Surface Water Utility coordinate with other ongoing capital improvement in the basin to incorporate water quality features wherever possible. In addition, it is recommended that opportunities for incorporating water quality features be explored in all future capital improvement projects. It is anticipated that such features can be used to directly enhance fish habitat and to encourage development of a sustainable fishery within this stream system. Design of the following three CIPs is currently underway in the Southgate Creek drainage basin: 42nd -43rd Avenue S Drainage Improvement Project The city plans to construct a storm drain along S 139th Street and 43rd Avenue S between 42nd Avenue S to S 133rd Street. (Note: The Fosterview Estates development will construct the section along 43rd Avenue S between S 136th and S 137th Streets.) This new drain (24 -inch) will convey runoff from a portion of 42nd Avenue S and the proposed Fosterview Estates 335/plan 43 Herrera Environmental Consultants development, located south of Southgate Park, to the existing ditch located on the south side of S 133rd Street. Project design is expected to be completed in 1996. Construction of a high flow bypass on S 133rd Street to divert peak flows away from lower Southgate Creek directly to the existing bypass system located at S 133rd and S 134th Streets will also be evaluated as part of this project. The city should also consider implementing a monitoring program to evaluate BMPs and CIPs implemented within the basin. Recommendations: Evaluate the feasibility of modifying the existing ditch along S 133rd Street to provide biofiltration capacity. Drainage facilities for the Fosterview Estates development will be designed in accordance with the 1990 King County Surface Water Design Manual as is currently required under the city's 1995 stormwater management ordinance. Pacific Highway Revitalization and Street Improvement Project: This project extends from S 152nd Street to the SR -599 interchange on Pacific Highway and consists of street lighting, curb/gutter, sidewalk, and drainage improvements. Although in the very early stages of development, installation of detention vaults under the highway is currently being considered to reduce peak flows to the natural drainages downstream of Pacific Highway (i.e., north fork, south fork, and middle fork of Southgate Creek). Recommendations Incorporate dead storage into all detention vaults to provide water quality treatment/sedimentation. Wet vaults should be designed according to the King County Surface Water Design Manual (King County 1990) as required under the draft surface water ordinance. Fostoria Storm Drain Project This project, completed in 1991, involved the construction of a bypass structure at S 133rd Street and S 134th Street, a 4 -feet by 8 -feet box culvert on S 133rd Street, and a 72 -inch storm drain on Interurban Avenue S to divert peak flows in the east drain (located on S 134th Street) away from lower Southgate Creek to reduce existing flooding problems. The city plans to construct a second high-flow bypass. structure on the east drain near the intersection of S 134th Street and 48th Avenue S to divert peak flows from the ditch on S 134th Street to the existing bypass on S 133rd Street/Interurban Avenue S. Included in the proposal are a wet vault/sediment trap to capture soils eroded from the upper basin and a bypass pipeline along S 134th Street. The bypass pipeline would tie into the bypass at S 133rd Street. This additional project is expected to reduce flooding problems along S 134th Street. About 300-400 feet of new bypass pipeline (approximately half of the total required) will be constructed along S 134th Street in 1996. The new pipeline will connect to the existing box culvert at S 133rd Street via an existing 30 -inch stub. 335/plan 44 Herrera Environmental Consultants Recommendations The wet vault/sediment trap should be designed in accordance with the King County Surface Water Design Manual (King County 1990) as required by the draft surface water management ordinance. This will ensure that the vault will remove sediment and associated pollutants from the runoff discharged from the upper basin. Options for constructing a wet pond rather than a vault should also be explored because wet ponds can provide additional water quality treatment via biological and chemical processes, and are easier to maintain than underground vaults. New catch basins that may be installed as part of the bypass pipeline construction should be equipped with a trap on the outlet to collect floatable materials such as oil. In addition, it is recommended that consideration be given to sizing new catch basins to provide dead storage for sedimentation/water quality treatment. For example, under the new city surface water ordinance, approximately 400 to 500 cubic feet of dead storage would be required to provide treatment for runoff from 400 feet of roadway. This additional storage could be incorporated into the existing system by installing larger (i.e., 54- to 72 -inch) catch basins instead of the standard 48 -inch catch basins. It is also recommended that accumulated sediment be removed from the S 134th Street ditch to increase channel capacity. The maintenance department has identified cleaning of the S 134th Street ditch as a high priority. Sediment deposition in the ditch has reduced its conveyance capacity and has nearly plugged the culvert at the lower end of the ditch, which restricts flow and fish passage to lower Southgate Creek. (Fish have been observed in the S 134th Street ditch). Reed canarygrass is well established along the banks of the ditch. The presence of dense vegetation in conjunction with low flow velocity likely provide some water quality benefit by enhancing the deposition of suspended sediment and associated pollutants. Cleaning operations should include a restoration component to maintain these features, as required under the sensitive areas ordinance. After excess sediment is removed from the ditch and culvert, the banks should be replanted to maintain water quality function and preserve aquatic habitat in the ditch. Because of the presence of cement kiln dust with elevated pH in the fill beneath the Fostoria Park Industrial Center, it is recommended that sediment in the lower portion of the ditch be tested prior to working in the ditch to determine whether these sediments classify as dangerous waste, as well as to identify necessary health and safety precautions for workers. An additional feature that should be considered as part of this project is: • Enlarge the culverts under driveways along S 134th Street to reduce flooding. 335/plan 45 Herrera Environmental Consultants Although this additional feature provide no direct water quality benefit, it will improve the drainage and aquatic habitat value in the area and thus should be considered as part of the overall project. Other Potential Stormwater Quality CIPs in Southgate Creek Basin Following is a list of potential CIPs that have been evaluated for improving stormwater quality in Southgate Creek. Projects are arranged by drainage area (see Figure A-15 in Appendix A). Central drain: 1. Sediment trap at S 135th Street 2. High-flow bypass at S 133rd Street East drain: 3. Sediment trap at 48th Avenue S 4. High-flow bypass at 48th Avenue S 5. Modify ditch on Interurban Avenue S North fork: 6. Sediment trap at 40th Avenue S 7. Stabilize channel above 40th Avenue S Middle fork: 8. Extend culvert at 40th Avenue S 9. Stabilize channel above 40th Avenue S South fork: 10. Detention ponds at 40th Avenue S and S 133rd Street 11 a. Stabilize channel below 40th Avenue S 11 b. Extend 12 -inch culvert under SR -99 Lower Southgate Creek: 12. High-flow bypass at S 133rd Street 13. Improve channel below S 133rd Street 14. Improve channel below S 133rd Place 15. Improve WDOT ditch along SR -599 Upper Southgate Creek: 16. Detention facilities in upper basin 17. High-flow bypass at SR -99 A brief description of each project is provided in the following sections; project locations are shown on Figure 15. Following the project descriptions is an evaluation of the individual CIPs based on criteria established by Ecology. Projects recommended for inclusion in the city's 335/plan 46 Herrera Environmental Consultants capital improvement program are selected and presented in the summary and recommendations chapter. Central Drain Project 1: Install a sediment trap above S 135th Street The central drain carries runoff from approximately 92 acres, of which 79 acres is residential, 7.9 acres is commercial, and 5.1 acres is light industrial. Commercial and light industrial land use in located primarily in the upper basin. Runoff is conveyed through a narrow, steep ravine (7 to 16 percent slopes) that begins just north of S 140th Street and continues beyond S 137th Street to S 135th Street. The ravine is eroding and consequently contributes sediment to the downstream drainage system. Below S. 135th Street, the central drain enters an asphalt -lined swale and is then piped under an industrial park before discharging to the bypass system on S 133rd Street/Interurban Avenue S. Sediment eroded from the ravine currently deposits in the 4 -foot by 8 -foot box culvert on S 133rd Street and the 72 -inch bypass pipeline on Interurban Avenue S. A sediment trap consisting of a wet pond would capture sediment eroded from the ravine before it reaches the bypass system. A wet pond is preferred over a wet vault, because ponds can provide additional removal of other stormwater-related pollutants such as nutrients and metals through chemical and biological processes that would not be available in a vault. In addition, underground vaults are often more difficult to maintain than open systems. Preliminary sizing estimates are provided below: Total Suspended Dead Storage Solids Removal (cubic feet) (percent) Design Standard 50,000 45-50 King County (1990) 140,000 70-75 Ecology (1990) 180,000 80 draft King County (1995) Tukwila's draft' surface water ordinance requires that new and redevelopment projects be designed in accordance with the current King County Surface Water Design Manual and also comply with the Ecology manual. Modification to the central drain does not qualify as new construction or redevelopment and consequently is not required to comply with existing drainage design standards. If possible, it is recommended that the sediment trap be 'designed with at least 50,000 cubic feet of dead storage to provide water quality treatment. A facility of this size would remove most of the sand and coarse silt present in the runoff, and some of the finer grained materials such as fine silt and coarse clay. Many of the pollutants in urban runoff are sorbed onto the particulates, particularly the fine-grained particulates such as silt and clay. Therefore, a 50,000 cubic foot sediment trap would also provide effective pollutant removal. Further site evaluation is needed to determine whether this size facility can be accommodated. A smaller 335/plan 47 Herrera Environmental Consultants trap could be used to reduce the downstream deposition problem, but would provide little pollutant removal. Project 2: Install high-flow bypass on the ditch that runs along the south side of S 133rd Street Project 2 is being considered as part of the 42nd - 43rd Avenue S drainage improvement project described in the previous section on existing CIP designs. East Drain Project 3: Install a sediment trap at 48th Avenue S Project 3 is part of the Fostoria Storm Drain Project described in the previous section oneexisting CIPs. Project 4: Install a high flow bypass at 48th Avenue S Project 4 is also included in the existing Fostoria Storm Drain Project described in the section on existing CIPs. Project 5: Modify the existing ditch on the east side of Interurban Avenue S at the intersection with S 133rd Street Runoff from about 1,000 feet of Interurban Avenue S is routed through a 200 -foot ditch on the east side of the roadway before discharging to the 72 -inch bypass pipeline on Interurban Avenue S. The existing ditch is located at the bottom of a deep cut located between the roadway and adjacent parking lots. The centerline of the ditch is approximately 8 to 10 feet below the surrounding ground surface. An outlet located at the downstream end of the ditch routes flow to the bypass at S .133rd Street. This project would consist of modifying the existing outlet structure by installing a standpipe to create dead storage along the bottom of the ditch, thus converting the ditch into a small wet pond. North Fork Southgate Creek Project 6: Install a sediment trap above 40th Avenue S The north fork basin above 40th Avenue S encompasses approximately 31 acres, including about 1.5 a9res of SR -99. The stream channel between SR -99 and 40th Avenue S is eroding. Channel gradients in this reach range from about 5 to 10 percent in the lower end near 40th Avenue S to as much as 20 percent along the upper end near SR -99. Sediment eroded from this section of channel is transported downstream and deposited in the relatively flat section below S 133rd 335/plan 48 Herrera Environmental Consultants Street. Extensive sediment deposition has dramatically reduced the capacity of lower Southgate Creek in the reach between S 133rd Street and S 133rd Place, which has resulted in the formation of a braided channel in this reach. Construction of a sediment trap above 40th Avenue S would reduce deposition in the lower channel, thereby reducing maintenance problems in this area. A sediment trap formerly existed in this location but was removed several years ago. It may be possible to construct a small wet pond in the ravine immediately upstream of 40th Avenue S to trap sediments and to remove stormwater pollutants. Preliminary sizing estimates are provided below: Total Suspended Dead Storage Solids Removal (cubic feet) (percent) Design Standard 40,000 45-50 King County (1990) 100,000 70-75 Ecology (1990) 110,000 80 draft King County (1995) Project 7: Improve/stabilize stream channel upstream of 40th Avenue S Extensive erosion is occurring in the north fork just upstream of 40th Avenue S. A fence located on the right bank above 40th Avenue S is being threatened where the channel has eroded the bank to depths of 5 to 10 feet. Project 7 involves regrading the stream bank, installing riprap armouring, and planting riparian and upland plants to stabilize the bank. Modification to the stream channel would require approval under the city's sensitive areas ordinance. Project 7 could be constructed separately or in combination with Project 6. Itis recommended that the city monitor flow in the north fork to determine the required design flow for stream improvements for both projects. Middle Fork Southgate Creek Project 8: Extend the existing culvert under 40th Avenue S The existing culvert underneath 40th Avenue S is 24 inches in diameter. However, there is a short section of 12 -inch pipe on the west side of 40th Avenue S that conveys flow from the middle fork underneath the private driveway at 13243 40th Avenue S to the larger 24 -inch culvert. This smaller pipe is undersized and causes flow to back up and overtop the driveway during large storm events. Project 8 involves extending the existing 24 -inch culvert underneath the driveway to reduce flooding problems. This project may be difficult to justify under the city's capital improvement program because it entails improvements to a private drainage system. However, because the existing flooding problem on this property is a direct result of increased runoff from development that has occurred in the upper basin, this project may be warranted to correct problems that developed before this area was annexed by the city. 335/plan 49 Herrera Environmental Consultants Project 9: Stabilize the stream channel upstream of 40th Avenue S About 4.6 acres drain to the middle fork at 40th Avenue S, including about 1.3 acres of multi- family residential, 1.9 acres of single family residential, and about 1.4 acres of SR -99. Springs located along the hillside east of SR -99 provide base flow in the stream. Culverts under SR -99 have created two channels on the middle fork. Increased runoff combined with steep slopes have caused the channels to erode. Erosion is most severe at the outlets from the two culverts. The homeowner at 13243 40th Avenue S has constructed a small pond on the middle fork. He regularly stocks the pond with fish, but noted that the fish usually die after the first rainstorm. The pond also tends to fill with sediment and must be cleaned out on a regular basis. Project 9 involves stabilizing the stream channels below the two culverts under SR -99 to halt erosion and reduce sediment load downstream. Similar to Project 8, this project also involves constructing drainage improvements on private property and may be difficult to justify under the city's capital improvement program. South Fork Southgate Creek Project 10: Install detention ponds at S 133rd Street and 40th Avenue S Project 10 involves construction of two detention ponds, one located on the west side of 42nd Avenue S (pond 1) and the other located on the south side of S 133rd Street (pond 4), to reduce peak flows in the south fork of Southgate Creek. These two detention ponds were originally identified and evaluated by Perteet (1993) in the Southgate Creek Basin ,Detention Analysis Report This report also identified two other potential regional detention pond sites on the south fork (ponds 2 and 3 located between 42nd Avenue S and S 133rd Street; see Figures 1 and 2 in Appendix E). However, ponds 2 and 3 provide little additional reduction in peak flows and are located entirely on private property; therefore they were not considered to be economical. Pond.1 is expected to reduce the 25 -year peak flow in the south fork from about 66 cfs to about 53 cfs (Perteet 1993). Pond 4 would also detain peak flows from the north fork. Under the proposed plan, peak flows in the north fork would be diverted along 42nd Avenue S and the S 134th Street right-of-way. The combination of ponds 1 and 4. would reduce the 25 -year peak flows in the north and south forks from about 86 cfs to about 55 cfs, which corresponds to an approximate 36 percent reduction in flow (Perteet 1993). Pond 1 lies entirely within city -owned property. This site was purchased by King County Parks in 1974 under the Forward Thrust Park Bond fund and turned over to the Tukwila Parks and Recreation Department in 1992. According to the Forward Thrust Bond, this property can only be used for park and recreation purposes. Construction of a detention pond at this site would require that the city set aside another similar area of equal value for park use. Additional research is needed to verify the requirements of the bond fund and determine whether other suitable alternatives could be developed that would allow this site to be used to construct a detention pond. 335/plan 50. Herrera Environmental Consultants acr Construction of pond 4 would require the purchase of about 1.6 1 es f private property. Preliminary sizing for detention ponds 1 and 4 is shown Pond Detention Volume (cubic feet) 1 93,000 137,000 4 It is recommended that dead storage be provided in each of the ponds $etc enhancehause th sedimponds ent deposition and removal of associated pollutants present in urban re located downstream of the steep ravines on the north and load in Southgate, Creeksat S 133rd sediment loads are expected to be substantial. Se that the Street (including contributions from the north, middle, and south t fiorks) sas ben eesti detention ati70 to 170 cubic yards per year (KCM 1992). For this analysis, ponds could be deepened by approximately 3 feet to provide dead storage for water quality treatment. This would create about 52,000 cubicfeet for treatment and sediment storage also 81,000 cubic feet of dead storage, respectively, in ponds 1 and 4. Provision of dead storage allows the ponds to be cleaned less frequently, without affecting the live storage needed for detention. Project 11 a: Improve and stabilize the stream channel between 40th Avenue S and S 133rd Street The south fork channel is eroding in the reach between 40th Avenue the roadway has eroded the upper end, near 40th Avenue S, discharge from a culvert underneath opposite bank, forming a large hole that serves as a source of sediment to he to aert1 42reaches s ofh Southgate Creek. Farther downstream, where the creek crosses private Avenue S, the stream overtops the channel during large storm events divert excess and floods fle ows away veway. Homeowners have tried to install a small berm along th from their property, but the stream continues to flood large storm e. Channel events. Just downstream of the driveway, the channel passes very closeto the ce capacity in this section is limited; the residents report that the channel nearly overtops during large storm events, threatening their house. Downstream of the 13422 property, the south fork as been in several locations. enters a concrete flume that is in poor condition and s dAs a r sultcthis section of the south Below the flume, the existing channel is also deeply incl. storm events. fork probably contributes a significant sediment load during large Channel improvements involve stabilizing the channel _ to reducestream bank Work in the erosion and correcting the existing flooding problem at the 13422 40th Avenue Sproperty. channel will require approval under the sensitive areas ordinance. In pebecause omhgate Creek crosses through private property in the area, the city will also have to obtain isn from the property owner to access the storm for rehabilitation culbtvert under 0th Avenue Sel pwith pr P rovements include 1) armoring the stream bank downstream of th to stabilize and protect the stream bank and 2) recontouring and reveegetatis the stream channel aquatic below the concrete flume to prevent erosion and protect existing c. 51 Herrera Environmental Consultants 335/plan Simple enlargement of the culvert underneath the driveway (which is the cause of the current flooding problem) may create problems farther downstream where the stream cuts near the house. When the channel overtops, excess flow currently drains toward the east and disperses across a field. City topographic maps indicate that a small stream may have existed in this area at one time. This stream flowed north and merged with the north, middle, and south forks just south of S 133rd Street. It may be possible to reestablish this drainage pathway for use as an overflow channel during large storm events (see Figure 15). Further investigation is needed to determine property ownership and evaluate the hydraulic requirements for a new channel in this area. Channel sizing will depend on local topography and how much detention can be realized in the upper basin. Alternatively, a tightline (piped) overflow could be installed if construction of an open channel is not feasible. Project 1l b: Extend 12 -inch pipe under SR -99 Discharge from an existing 12 -inch culvert under SR -99 has eroded the hillside below the highway contributing to the sediment load in the south fork of Southgate Creek. Project 11 would extend the 12 -inch pipe a distance of approximately 50 feet to a concrete headwall structure on a storm drain located farther downhill. This project would result in tightlining the runoff from SR -99 all the way to the south fork just above 40th Avenue S. Southgate Creek (Downstream of Convergence of North, Middle, and South Forks) Project 12: Construct a high-flow bypass at S 133rd Street Project 12 is an extension of Project 2, which would enable the peak storm flows from the north, middle, and south forks, as well as the central drain, to be diverted to the existing bypass on S 133rd Street/Interurban Avenue S. The existing S 133rd Street/Interurban Avenue S bypass was designed to handle peak flows from all of Southgate Creek. Project 12 involves construction of approximately 650 feet of pipeline under S 133rd Street, from the existing 42 -inch stub on the manhole at the head of the S 133rd Street/Interurban bypass to the existing 36 -inch culvert on Southgate Creek at the intersection with 42nd Avenue S. Construction of the bypass on S 133rd Street was recommended in the 1993 Surface Water Management Comprehensive Plan. A diversion structure would also be installed at the outlet of the 36 -inch culvert to divert peak flows to the bypass, while maintaining base flow to lower Southgate Creek. Project 12 would reduce flow in lower Southgate Creek (i.e., downstream of S 133rd Street). This would not only reduce flooding, but would also reduce the extent of modifications to the downstream channels, to provide habitat for aquatic organisms such as overwintering habitat for fish. 335/plan 52 Herrera Environmental Consultants Project 13: Improve the stream channel downstream of S 133rd Street where the creek crosses a horse pasture Sediment eroded from the steep sections of the north, middle, and south fork stream channels above 40th Avenue S has deposited in the horse pasture located in the relatively flat area immediately north 'of S 133rd Street. As a result, the creek now exists as a braided channel through the pasture, which floods during large storm events and contributes significant sediment loads downstream. In addition, the existing braided channel creates a barrier to fish, preventing them from reaching the upper tributaries of Southgate Creek (i.e., north, middle, and south forks). Project 13 was identified by KCM (1992) and involves construction of a new channel to safely convey storm flows and to improve aquatic resources in this section of the stream. A low -flow channel would be constructed to convey base flow and runoff from smaller storm events and to permit fish passage. The channel would also be configured with a broader, overflow section to safely convey the peak runoff from larger storm events. Bank areas would be stabilized by planting with suitable vegetation. In addition, the existing culvert under S 133rd Place at the lower end of this reach, which was installed with a reverse grade, would be replaced. Because of the negative slope, sediment has deposited along the upstream end and has partially blocked this culvert. Two alignments are possible, one locating the new channel in the vicinity of the existing channel that cuts through the center of the horse pasture, and the other relocating the channel along the northern edge of S 133rd Street. Construction of either of the new channels would require approval under Tukwila's sensitive areas ordinance. In addition, a mitigation plan will have to be prepared prior to approval. Relocation to the S 133rd Street right-of-way is recommended to permit easy access for maintenance and to preserve use of the horse pasture. One possible option to consider with project 13 is construction of a sediment trap/pond immediately downstream of the existing culvert under S 133rd Street. This area, which exhibits a fairly low stream gradient, currently functions as a deposition area and requires frequent dredging to maintain capacity. Depending on the timing .of upstream improvements (i.e., Projects 6 through 11), it may be necessary to construct a sediment trap at this location to prevent sediment deposition from damaging the newly constructed channel. Project 14: Improve the existing ditch between S 133rd Place and SR -599 The existing ditch is overgrown with reed canarygrass, which reduces the channel carrying capacity and has choked out other more 'desirable vegetation. This project involves modifying the existing channel cross-section to improve conveyance capacity and provide aquatic habitat. Work in the channel requires approval under the city's sensitive areas ordinance. Channel modifications include recontouring about 400 feet of the channel cross-section to provide both a low -flow channel that permits fish use and passage under low -flow conditions and a larger overflow channel for peak storm flows (KCM 1992). Emergent plants would be planted along the stream edge, and riparian vegetation would be planted along the corridor to provide shading. 335/plan 53 Herrera Environmental Consultants The city may want to consider relocating this section of the stream along the city right-of-way to improve access for maintenance, reduce possible impacts on private property, and enhance the stream habitat. Stream relocation would provide for a more natural meander but would require approval under Tukwila's sensitive areas ordinance. Project 15: Improve the existing ditch in the Washington Department of Transportation right-of- way along SR -599 Project 15, originally described by KCM (1992), involves enlarging the existing channel along the SR -509 right-of-way and extending it to the south to connect with the Southgate Creek system at S 133rd Street. The channel would be designed to convey storm and base flows from the upper Southgate Creek system as well as from the east drain, and would be configured to allow fish passage and provide aquatic habitat through construction of weirs for pool formation and stabilization of the channel bottom. Project 15 is not necessary if upstream controls such as detention (Project 16) or high-flow bypasses (Projects 2, 12, and 17) are constructed. Upper Southgate Creek Basin Project 16: Provide detention in the upper basin above SR -99 Incorporation of detention into the existing drainage system serving the upper basin was considered a high priority to prevent runoff from these highly developed areas from eroding the steep ravines below SR -99. The approach used in preparing this plan has been to first correct flow-related problems in the upper basin wherever possible, then identify additional facilities as necessary in the lower basin to improve water quality and aquatic habitat throughout Southgate Creek. Construction of detention facilities in the upper basin would reduce peak flows and subsequent erosion problems in Southgate Creek. The upper Southgate Creek basin above SR -99 is almost completely developed. This existing development occurred prior to the esiablishment of drainage standards. Consequently, runoff from urban areas in the upper basin is discharged directly to the natural drainage channels without being detained or treated. KCM (1992) estimated the predevelopment 25 -year peak flows in Southgate Creek at S 133rd Street at approximately 8 cfs, compared to the current level of about 111 cfs. The Southgate Creek Basin Detention Analysis Report (Pelted 1993) showed that detention sites are not available below SR - 99 to adequately control flow in the creek. Because the highly erosive sections of the north, south, and middle forks occur in the steep ravines downstream of SR -99, incorporation of detention facilities in the upper basin to reduce peak flows would also help to reduce erosion in these areas. A preliminary analysis was conducted to determine the amount of detention volume needed to reduce peak flows in the north, middle, and south forks of Southgate Creek at SR -99 to approximate predevelopment levels. It is assumed that detention would be incorporated 335/plan 54 Herrera Environmental Consultants incrementally either through modification required as part of future site redevelopment projects or under the city's CIP program. Each basin has been divided into smaller subbasins based on the layout of existing storm drains. Existing storm drain mapping for the area west of SR -99 is incomplete. For this analysis, it is' assumed that runoff from the portion of the south fork drainage located south of S 144th Street is routed east toward SR -99 and conveyed northward in a pipeline along SR -99. Results of the detention analysis are summarized in Table 12. The analysis does not take into account the effects of private stormwater control facilities that may already exist. Commercial properties along SR -99, particularly those that have undergone development or redevelopment in the recent past (e.g., Larry's Market) may have installed stormwater controls. Further investigation is needed to identify the locations of private storm drain facilities so that their effects can be taken into account in the hydraulic analysis. Dead storage for water quality treatment has been incorporated into the detention pond sizing analysis. It is assumed that dead storage would be provided below the active storage volume needed for detention. The following three methods are used to estimate dead storage volumes: Design Criteria Total Suspended Solids Removal (percent)° Reference 0.33 of 2 -year, 24-hour storm 45-50 King County (1990) 0.64 of 2 -year, 24-hour storm 70-75 Ecology (1992) VbN, = 3.0b 80 Draft King County (1995) . aReference: FHA (1988) bWhere Vb = dead storage volume and Vr = volume of runoff from mean annual storm. The results shown in Table 12, indicate that approximately 15 acre-feet of active storage plus 3.5 to 9.3 acre-feet of dead storage are needed to fully detain and treat stormwater from the upper basin. There are few, if any, suitable parcels available to construct detention ponds of the size needed to control stormwater runoff from this portion of the basin. Potential sites identified based on aerial photographs are described below: • North fork: 0.11 -acre lot on the southwest corner of S 133rd Street and 37th Avenue S. • South fork: 0.27 acre lot on the southwest corner of S 143rd Street and 37th Avenue S. 1.1 acre lot at the corner of 33rd Avenue S and 34th Place S. Further investigation is needed to determine whether these sites are suitable for construction of stormwater facilities and are available for purchase. Otherwise, the only other option for providing detention and treatment in the upper basin is to construct underground facilities (i.e., vaults and oversized pipes). Underground facilities are more expensive to construct and maintain than above ground facilities. Moreover, they do not afford the additional chemical/biological 335/plan 55 Herrera Environmental Consultants treatment that can be achieved with open facilities. Therefore, it is recommended that the city explore other detention opportunities to achieve the level of flow reduction needed to protect aquatic habitat in Southgate Creek. Options that the city is considering include requiring redevelopment projects to provide detention not only for the newly impervious areas being created, but also for existing impervious surfaces within the site that were developed before these areas were annexed by the city and to require that detention be incorporated as part of future street improvement projects. Efforts to incorporate detention in the upper basin should be coordinated with other ongoing CIPs such as the SR -99 street improvement project (see previous section on ongoing CIPs) to develop a systematic plan for increasing stormwater detention capacity. Project 17: Install high-flow bypass at SR -99 for north, middle, and south forks Project 17 is an alternative to upstream detention for handling peak flows from the upper basin. It involves construction of a bypass pipeline to divert peak storm flows around the steep ravines on the north, middle, and south forks of Southgate Creek east of SR -99. This option would require construction of three diversion structures (at the heads of the ravines on the north, middle, and south forks) and a pipeline to convey excess runoff from the basin above SR -99 down to the existing bypass pipe on S 133rd Street. Base flows in the three streams would be maintained; only the peak storm flows would be diverted into the bypass pipeline. To minimize excavation requirements, the bypass would have to be routed across private property between SR -99 and 42nd Avenue S. COST ESTIMATES FOR STORMWATER POLLUTION CONTROL ALTERNATIVES Preliminary cost estimates for the individual stormwater pollution control alternatives are summarized in Table 13. Costs are based on 1995 rates and include engineering and construction costs, but do not consider costs associated with purchasing land or acquiring easements for construction of necessary facilities. Therefore, costs for alternatives such as Projects 10, 16, and 17, which involve construction outside the public right-of-way, will be higher than shown in Table 13. Costs for detention facilities in the upper basin (Project 16) are estimated assuming construction of ponds with active storage for detention plus dead storage for water quality treatment. Cost estimates for water quality programs are shown either as lump sum costs for discrete projects or as annual costs for projects that require ongoing efforts by city staff. Program elements requiring city staff involvement have been evaluated assuming a full-time equivalent (FTE) rate of $50,000 per year (including overhead) for a water quality engineer and $30,000 per year for field personnel. 335/plan 56 Herrera Environmental Consultants COMPARISON OF STORMWATER POLLUTION CONTROL ALTERNATIVES Stormwater pollution control alternatives are evaluated based on the following three criteria: • Effectiveness in improving water quality and/or correcting an existing • drainage problem • Ease of implementation, considering both technical feasibility and public acceptance • Cost. Results of alternative evaluation are shown in Table 14. Capital Improvement Projects Although detention and high-flow bypass options potentially offer the greatest basinwide benefits, they are among the most expensive facilities considered for the Southgate Creek basin. In particular, construction of a high-flow bypass (Project 17, estimated cost $1,700,000) or detention facilities (Project 16, estimated cost $654,000) in the upper basin above SR -99 to reduce peak flows and subsequent erosion problems in the north, middle, and south forks are the most expensive options. Cost estimates for these two projects (see Table 13, Appendix B) reflect engineering and construction costs but do not take into account the costs associated with acquiring easements or ownership of the land needed to construct the necessary facilities (e.g., bypass pipeline, detention ponds). Furthermore, the underground detention facilities may be two to three times more expensive than open facilities. The least expensive bypass option is the lower Southgate Creek bypass on S 133rd Street (Project 12, estimated cost $292,000). This project was originally recommended in the Fostoria Basin Drainage Study (KCM 1986). The S 133rd Street/Interurban Avenue S bypass, constructed in 1991, is designed to handle the peak flows from upper Southgate Creek (north, middle, and south forks) and the central drain. Consequently, this project only requires construction of the necessary diversion structures and"approximately 650 feet of pipeline along the S 133rd Street right-of-way, from the existing 36 -inch culvert at 42nd Avenue S to the head of the existing bypass pipeline at S 134th Street. No modifications are needed to the existing S 133rd Street/Interurban Avenue S bypass system. Construction of Project 12 would also eliminate the need for the central drain bypass (Project 2), since peak flows from the central drain could be diverted directly into the new pipeline on S 133rd Street. Construction of the two detention ponds at 40th Avenue S and S 133rd Street (Project 10, estimated cost $319,000) is the most feasible detention alternative. Although a high-cost option, these two ponds in combination would reduce the 25 -year peak flow rates in the south and north forks by about 36 percent. In addition, Project 10 is considerably less expensive than the upper basin detention alternative (Project 16, estimated cost $654,000) and would also provide water 335/plan 57 Herrera Environmental Consultants quality treatment and sediment storage below the highly erosive sections on the north and south forks if dead storage is incorporated into the pond design. Construction of sediment traps on three of the Southgate Creek tributaries that are currently experiencing erosion problems (i.e., east drain, central drain, and north fork) is expected to yield substantial water quality benefit at a medium cost (less than $100,000 per facility). These facilities would also reduce maintenance requirements by consolidating sediment deposition at a single location, rather than allowing sediment to deposit along the entire downstream channel. Preliminary review of aerial photographs and field reconnaissance indicates that these facilities could be constructed as open wet ponds rather than underground vaults. However, a more detailed site evaluation is needed to determine what size wet pond could be constructed within the area available at each site. Channel improvements have been identified at numerous locations throughout the Southgate Creek basin to correct existing erosion and flooding problems. Most channel improvement projects have been assigned a medium rating for effectiveness, implementability, and cost. However, two projects on lower Southgate Creek (Project 13 --below S 133rd Street, and Project 14 --below S 133rd Place) are considered be more important and thus have been given a higher effectiveness rating. Project 13 (estimated cost $140,000), below S 133rd Street, would reestablish the channel where it has become braided as a result of excessive sediment deposition. This project would improve channel conveyance capacity to reduce flooding, and the amount of sediment and other pollutants transported from the adjacent horse pasture when the existing channel overtops, and would also improve aquatic habitat through this section of the stream. Similarly, Project 14 (estimated cost $55,000) would enlarge the existing channel and improve aquatic habitat in the reach downstream of S 133rd Place. Water Quality Programs The water quality program elements are rated fairly evenly. Most programs are in the medium to high ranking (i.e., 2 to 3 numerical rating) for effectiveness, ease of implementation, and cost. The two primary exceptions are the catch basin cleaning and the private system maintenance programs. Catch basin cleaning would be more expensive than the other program elements if an additional vactor truck (estimated purchase price of $250,000) is required to achieve more frequent cleaning of catch basins and other stormwater facilities in Southgate Creek. It may be possible to increase cleaning frequency in the Southgate Creek basin simply by shifting maintenance crew schedules. Modifications to maintenance operations could probably be applied only on a limited basis and would not enable the Department of Public Works to increase catch basin cleaning frequency throughout the city. Alternatively, purchase of an additional vactor truck would yield benefits beyond the Southgate Creek drainage, since the additional truck would be available for use city wide. Developing a program to oversee the maintenance requirements for private storm drain systems established under the 1995 surface water management ordinance may require a significant effort by city staff. The level of effort needed would depend on the number of private systems in 335/plan 58 Herrera Environmental Consultants operation within the Southgate Creek basin. To ensure that these private systems are properly maintained by their owners, the city would need to implement fairly rigorous record-keeping, inspection, and technical assistance programs. For costing purposes, it was assumed that private systems would be maintained by the individual owners. However, the surface water management ordinance includes a provision to enable the city to maintain these private systems and to bill the owners for the service. If the city elects to provide this service to private system operators, the expense of the program will increase significantly. Citizens Action Committee Project Ranking Members of the citizens action committee were asked to select those projects they believe are the most important to aid in prioritizing the plan alternatives. The five -person committee consists of representatives from two local businesses and three private residents. A meeting was held with the committee on November 30, 1995 to discuss the individual program elements and CIPs and to solicit comments on the preferred projects. Each of the four committee members in attendance was allowed to select three preferred water quality program elements and five CIPs from the list of alternatives. Results of the informal ranking process are summarized below with the number of votes listed on right: 335/plan Water Quality Programs Map and inventory stormwater facilities 3 Improve and expand existing storm drain maintenance program 3 Conduct illicit connection surveys 3 Sponsor a stream cleanup project with local residents 2 Disseminate information to the public via local newsletters 1 Capital Improvement Projects Install detention ponds on the south fork of Southgate Creek upstream of 40/42nd Avenue S and S 133rd Street Investigate and install detention facilities where feasible in the upper basin above SR -99 Construct an overflow structure/high flow bypass on the central drain at S.133rd Street Install a sediment trap on the north fork of Southgate Creek upstream of 40th Avenue S Improve and stabilize the south fork channel of Southgate Creek between 40th Avenue S and S 133rd Street 3 3 2 2 2 59 Herrera Environmental Consultants Improve the lower Southgate Creek channel below S 133rd Street where the stream crosses a horse pasture 2 Install a sediment trap in the central drain upstream of S 135th Street 1 Improve and stabilize the north fork channel of Southgate Creek upstream of 40th Avenue S 1 Extend the existing culvert under 40th Avenue S at the middle fork of Southgate Creek to private driveway 1 Stabilize the middle fork channel of Southgate Creek upstream of 40th Avenue S 1 Improve the existing ditch along lower Southgate Creek below S 133rd Place 1 Because most of the committee members have experienced flooding problems at their property (either in the past or ongoing), they were most interested in the alternatives that provide drainage system improvements to correct flooding problems. Committee members tended to prefer high flow bypass or tightline options to divert peak stormwater flows from the natural drainage channels. In general, options designed to improve or enhance water quality and protect aquatic resources in Southgate Creek were viewed favorably but were considered lower priority compared to water quantity and flood reduction projects. With respect to water quality programs, the committee recognized that available drainage system maps for the Southgate Creek basin are incomplete and acknowledged that mapping and inventory efforts are needed. Storm drain maintenance efforts also received a high ranking. Again, the committee recognized that effective maintenance is essential to ensuring the proper operation of these facilities. From a water quality standpoint, the presence of non-stormwater discharges in Southgate Creek and its tributaries (based on local observations of sheens, odors, and soap suds) provides the most visible evidence of potential water quality problems. Consequently, committee members generally agreed that field surveys to locate and eliminate illicit connections would be beneficial. Although stream cleanup projects received a lower ranking, the committee recommended that if the city elects to sponsor a community project, the Southgate Park area should be given the highest priority. 335/plan 60 Herrera Environmental Consultants SUMMARY AND RECOMMENDATIONS Based on the information gathered as part of this investigation, it is clear that stormwater pollution does not currently pose a serious threat to water quality in Southgate Creek. However, the data show that there are ongoing stormwater-related problems in the basin that could affect water quality in the future and have already damaged aquatic resources in the basin. The primary concerns identified by this study involve 1) flow-related erosion problems that have damaged and continue to threaten aquatic resources, 2) elevated fecal .coliform bacteria counts throughout the drainage basin, and 3) a history of contaminant spills associated with improper chemical storage and disposal practices. A series of structural controls has been identified to correct the flow-related erosion problems that exist in the basin and to incorporate stormwater treatment functions into the existing drainage system where feasible. In addition, a water quality program has been devised to address water quality and contaminant issues and to facilitate implementation of stormwater requirements that have recently been adopted by the city. The stormwater pollution abatement strategies recommended here for implementation by the Tukwila Surface Water Utility are presented and explained in detail in the previous chapter. These recommendations are prioritized and presented in summary form in the sections below. An environmental checklist has been prepared in support of this management plan. In adhion, separate environmental reviews will be conducted for each CIP as part of the usual plan, specification, and estimate process. CAPITAL IMPROVEMENT PROJECTS Following is a list of stormwater quality control projects that are recommended for incorporation into the Storm and Surface Water Utility's capital improvement program. Projects are listed in order of priority, along with a brief explanation. Details of each project are presented in the previous chapter. Project locations are shown on Figure 15. 335/plan • Project 10. Construct detention ponds on Southgate Creek at 40th Avenue S and S 133rd Street. Ponds are to be designed with live storage for detention and dead storage for water quality treatment. These two ponds are expected to reduce the 25 -year peak flow in Southgate Creek at S 133rd Street from about 91 cfs to about 62 cfs (Perteet 1993) and will provide sediment storage and treatment for runoff from the north and south forks of Southgate Creek. Estimated cost: $319,000 (not including cost to purchase land for the lower pond at S 133rd Street). • Project 12: Install a high-flow bypass in Southgate Creek on S 133rd Street at the culvert under 42nd Avenue S to divert peak flows to the existing bypass on S 133rd Street/Interurban Avenue S. This project includes construction of 61 Herrera Environmental Consultants a diversion structure to maintain base flow to the existing channel downstream of S 133rd Street and about 650 feet of bypass pipeline under. S 133rd Street. It will reduce erosion and protect aquatic resources in the downstream channel and also represents the completion of the Fostoria basin bypass project begun in 1986. Estimated cost: $331,000. • Project 13: Relocate and improve the Southgate Creek channel downstream of S 133rd Street to improve channel conveyance capacity and reduce. erosion/pollutant transport that currently occurs during large storm events when the stream overtops its channel and floods the adjacent horse pasture. It is recommended that the channel be relocated along S 133rd Street and 44th Avenue S. The project includes construction of about 600 feet of new stream channel, along with stream bank and riparian plantings for channel stabilization and shading. This project requires review and approval under Tukwila's sensitive areas ordinance. Estimated cost: $140,000 with culvert replacement (culvert under S 133rd Place), $76,000 without culvert replacement. (One possible option to consider is the construction of a sediment trap/pond immediately downstream of the existing culvert under S 133rd Street). • Project 14: Improve the Southgate Creek channel downstream of S 133rd Place. The project involves removing nuisance vegetation and recountouring/replanting the stream bank to improve channel conveyance capacity and aquatic resource value. Located just upstream of the fish ladder and culvert under SR -599, this project is an important link in the overall improvement of Southgate Creek, because it is the first section of natural channel that exists above the outfall to the Duwamish River. This project also requires review and approval under Tukwila's sensitive areas ordinance. Estimated cost: $55,000. • Project 8: Extend the culvert on the middle fork under 40th Avenue S where it crosses the private driveway at 13243 40th Avenue S, to reduce flooding. This is a rather small project to correct an existing problem. Although this is a localized problem, improvements were promised to the local property owner before this area was annexed by the city of Tukwila. Construction of this project will help to foster community support and goodwill in the city's stormwater management efforts. Estimated cost: $14,000. Project 3: Construct a sediment trap on the east drain at 48th Avenue S. This project involves constructing a wet pond on the south side of 48th Avenue S to trap sediments, and enlarging culverts under the driveway and cleaning and improving the existing roadside ditch along S 134th Street to increase channel carrying capacity. The sediment trap will reduce future costs for maintaining the existing ditch by consolidating most of the sediment deposition in a single location. Estimated cost: $41,000. 335/plan 62 Herrera Environmental Consultants 335/plan • Project 16: Explore opportunities for constructing detention facilities in the upper Southgate Creek basin above SR -99. Preliminary analysis indicates that a large amount of detention storage is needed to fully control peak flows in the north, middle, and south forks. However, there are few open sites available for construction of large detention ponds. A review of available undeveloped land is needed to determine whether detention ponds are feasible. Engineering and construction costs for providing detention for the entire upper basin above SR -99 are estimated to be $650,000, assuming that suitable sites can be found for construction of open ponds. Construction of large underground facilities will likely be cost -prohibitive (i.e., two to three times the cost of open detention ponds). However, the use of underground vaults may be suitable to detain flows from small, isolated catchment areas. One possibility that is currently being explored by others is to incorporate detention as part of an ongoing street improvement project on SR -99 (Cecil 1995' personnel communication). However, drainage is only one component of the project and is not the major focus of that study. A comprehensive approach is needed to determine whether upper basin detention is feasible. Existing drainage maps, although incomplete, indicate that it may be difficult to separate flows from SR -99 from the upper basin runoff without making significant modifications to the existing storm drain system. Therefore, it is recommended that possible detention sites be reviewed and a hydraulic analysis be performed to evaluate the feasibility of incorporating detention storage in the upper basin. Additional information on the existing storm drain system is needed to complete the evaluation. Estimated evaluation cost: $20,000. • Project 11 a: Improve and stabilize the south fork channel between 40th Avenue S and S 133rd Street. This project involves stabilizing sections of the channel damaged by erosion, and possibly installing a high-flow bypass to prevent flooding in the vicinity of the property at 13422 40th Avenue S. Channel improvements will reduce the sediment load in this section of the stream, where extensive erosion is occurring. The need for the bypass is dependent on the amount of detention storage that can be achieved in the upper basin. Estimated cost: $210,000 (without bypass). • Project 11b: Extend the 12 -inch culvert under SR -99 to connect with the existing storm drain located downhill at the concrete headwall about 150 feet east of SR -99. This project will reduce erosion and subsequent sediment loading in the south fork below SR -99. Estimated cost: $17,000. 63 Herrera Environmental Consultants WATER QUALITY PROGRAM It is recommended that the city develop a water quality program within the Surface Water Utility to reduce the amount of pollutants released into stormwater runoff from the various nonpoint sources in the Southgate Creek basin. This program would 1) expand upon the basin characterization efforts conducted as part of this project to identify and control potential ongoing sources that are suspected in the basin, 2) establish mechanisms for implementing the various stormwater quality control programs that are currently in place or soon to be adopted under city ordinances, and 3) establish a public education program to encourage local businesses and residents to implement best management practices for controlling nonpoint sources of pollution. Until now, there has been no concerted effort within the city to encourage and enforce source control efforts by the local community. Stormwater pollution control efforts conducted in the Southgate Creek basin could serve as a test program for the rest of the city. Depending on the success of actions taken in this basin, the city may consider expanding the program into other areas. It is recommended that the utility focus first on developing the necessary framework to implement a stormwater quality program in Southgate Creek. Priorities for the water quality program are described below: 335/plan • Designate a utility staff person who will be responsible for coordinating the water quality program. The program coordinator will oversee and implement the various program activities as well as be responsible for coordinating with other city departments to obtain technical assistance 'and_ to define each department's role in supporting pollution control efforts (e.g., maintenance department, Surface Water Utility, Sewer Utility, Department of Community Development, Fire Department). Water pollution issues are not unique to the Surface Water Utility. Consequently, cooperation among the various city departments is essential to the development of an effective stormwater quality program. Coordination efforts will also benefit the program by increasing efficiency and reducing overlap among the departments, particularly in the areas of public education and inspection services. • Inventory and map the locations of public and private drainage facilities in the Southgate Creek basin, including conveyance systems (e.g., pipes, culverts, channels, and roadside ditches), and detention and treatment facilities. Many of the other program activities rely on accurate storm drain information. Inventorying and mapping are recommended as a top priority for Southgate Creek, because current mapping is incomplete, particularly in the upper basin above SR -99. • Establish procedures for maintaining existing storm drain facilities (both public and private) to enhance the performance of these systems, particularly those that provide stormwater treatment. It is recommended that the utility 64 Herrera Environmental Consultants work with the maintenance department to develop appropriate procedures that can be readily adopted by maintenance crews. Establishing standard operating procedures will aid in focusing maintenance efforts on improving pollutant removal performance as well as maintaining conveyance capacity. It will also help in planning and budgeting maintenance operations. As part of this effort, it is recommended that the utility and maintenance department evaluate options for increasing the frequency of catch basin cleaning operations in the Southgate Creek basin, so that catch basins are cleaned at least once every 2 years. The maintenance department should also develop a list of specific problem areas within the basin to identify those facilities that may require more frequent cleaning. This list can then form the basis for scheduling catch basin cleaning activities. • Develop a program for overseeing the operation and maintenance of private storm drain systems in the Southgate Creek basin. This program element involves implementing an inspection program to ensure that private systems are properly maintained, as required under the draft surface water management ordinance, and developing a record-keeping system to track the performance of private operators. • Remove sediment and restore vegetation in S 134th Street ditch. Once the initial development phase is completed, the utility can begin to implement additional phases of the program. Implementation will likely progress as staffing and resources allow. It is recommended that the first efforts be directed toward providing technical assistance to local businesses and residents concerning appropriate stormwater best management practices, conducting illicit connection surveys to identify non-stormwater discharges to the local drainage system, and implementing a public education program to encourage residents to participate in preventing stormwater pollution in Southgate Creek. To be effective, the city will need to work actively with the local community to educate residents about best management practices as well as to enforce local codes and ordinances pertaining to stormwater issues. Recommended activities for the technical assistance program are described below: 335/plan • Work with local businesses that operate private storm drain systems to ensure that they implement appropriate maintenance programs. This can be accomplished simply by having maintenance crews advise owners about proper procedures for cleaning and maintaining drainage systems during inspections of private drainage facilities. The water quality program. coordinator should then follow up, either by mail or in person, to provide additional assistance and to confirm that maintenance is being conducted, as required. 65 Herrera Environmental Consultants • Establish a program to investigate high-priority businesses whose activities pose a potential threat to stormwater and assist them in implementing appropriate best management practices to prevent stormwater pollution. The numerous automotive repair and sales facilities located in the Southgate Creek basin represent a type of business whose activities are likely to affect stormwater. It is recommended that the city utilize the resources of the Local Hazardous Waste Program operated by the King County Department of Metropolitan Services (formerly Metro) to implement this portion of the program. Illicit connection surveys are recommended to identify the causes of elevated fecal coliform bacteria numbers found at sampling stations throughout the Southgate Creek study area. The following areas should be targeted: • SR -99 (Pacific Highway) and. S 134th Street commercial/industrial corridors • Along 40th Avenue S where members of the citizens action committee have identified non-stormwater discharges. A public education program is needed to promote public awareness of stormwater pollution issues as well as to disseminate information to local residents and the business community about regulatory requirements and effective best management practices. It is recommended that the initial efforts target the following activities: • Use local newsletters and community organizations such as the Hazelnut, the Foster Community Club (which publishes the Foster Community News), and the Duwamish Improvement Club to disseminate information about stormwater issues and requirements. The water quality program coordinator should be responsible for preparing articles and periodically attending community club meetings to discuss stormwater problems and programs offered by the city. • Implement a community cleanup project in Southgate Park to encourage local residents to participate in the city's stormwater management program. The city should also consider developing an inspection and monitoring program to evaluate BMPs and CIPs implemented in the Southgate Creek basin. New drainage structures such as wet ponds or vaults should be included in the city's regular maintenance program to ensure proper operation. In addition, stream rehabilitation and stabilization projects should be inspected periodically to document that these projects continue to be effective, both in maintaining stream conveyance capacity and in providing suitable aquatic habitat. Channel erosion and sedimentation problems should be documented and corrected as soon as possible. 335/plan 66 Herrera Environmental Consultants Water quality monitoring could also be conducted in individual drainages where corrective actions have been taken. For example, depending on the results of the illicit connection surveys, it may be necessary to conduct targeted sampling efforts to identify problem areas and to document improvements after source controls have been implemented. Although the sampling conducted as part of this study was limited, few water quality problems associated with discharges of contaminants to the storm drain system were identified in the basin. It may be necessary to conduct focused sampling efforts in the future to confirm that the Southgate Creek drainage system continues to exhibit good water quality conditions. In addition, information obtained during drainage inspections may reveal site specific problems that require additional investigation. Therefore, the city should be prepared to conduct additional water quality studies if necessary. 335/plan 67 Herrera Environmental Consultants 335/plan 68 Herrera Environmental Consultants REFERENCES Cecil, R. October 2, 1995. Personal communication (phone conversation with Beth Schmoyer, Herrera Environmental Consultants). Bell Walker Engineers, Bellevue, WA. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. FWS/OBS-79/31. U.S. Fish and Wildlife Service, Office of Biological Services, Washington, D.C. Earth Consultants. 1991. Preliminary subsurface site characterization, Fostoria Park Industrial Center, Tukwila, WA. Prepared for Fostoria Park Associates by Earth Consultants, Inc., Bellevue, WA. Ecology. 1990. Initial site investigation report, Structural Instrumentation, Inc. Washington Department of Ecology, Bellevue, WA. Ecology 1991. Initial site investigation report, American Tire Wholesalers. Washington Department of Ecology, Bellevue, WA. Ecology. 1992a. Stormwater management manual for the Puget Sound basin (Volume 1: technical manual). Washington Department of Ecology, Olympia, WA. Ecology. 1992b. Stormwater program guidance manual for the Puget Sound basin (Volume 2: supplemental guidance). Washington Department of Ecology, Olympia, WA. Glanton, T., M.T. Garrett, and B. Goloby. 1992. The illicit connection --Is it a problem? Water Environment and Technology 4(9):63-68. Herrera. 1993. Pipers Creek bacteriological source tracking investigation. Prepared for Seattle Engineering Department by Herrera Environmental Consultants, Seattle, WA. Herrera. 1994a. Water quality monitoring and quality assurance project plan—Fostoria stormwater quality management plan. Prepared for Tukwila Department of Public Works by Herrera Environmental Consultants, Seattle, WA. Herrera. 1994b. Implementation strategy, Renton/Lake Washington pollution abatement program. Prepared for Renton Surface Water Utility by Herrera Environmental Consultants, Seattle, WA. Jeffries, M. and D. Mills. 1990. Freshwater ecology: Principles and applications. Belhaven Press, New York, NY. Jones and Stokes. 1990. City of Tukwila, Watercourse rating data sheets. Prepared for city of Tukwila by Jones and Stokes Associates, Bellevue, WA. 335/plan 69 Herrera Environmental Consultants KCM. 1986. City of Tukwila, Fostoria basin drain study. Prepared for Tukwila Department of Public Works by Kramer, Chin & Mayo, Inc., Seattle, WA. KCM. 1992. City of Tukwila: Southgate Creek fish enhancement project, preliminary design report. Prepared for Tukwila Department of Pubic Works by Kramer, Chin, and Mayo, Seattle, WA. King County. 1990 (updated in 1992). Surface water design manual. King County Public Works Department, Surface Water Management Division, Seattle, WA. King County. 1995. Draft surface water design manual. King County Public Works Department, Surface Water Management Division, Seattle, WA. Loftness, S.J. 1981. Washington state lubricating oil consumption and disposition. WAO ENG - 81 -07. Washington State Energy Office, Olympia, WA (as cited by Ridgley and Galvin 1982). Martin, M.J. and N. Moreno. August 30, 1993. Personal communication (letter to Robert Levinson, Fostoria Park Associates). Earth Consultants, Inc., Bellevue, WA. Merrill, M.S. May 16, 1989. Personal communication (letter to Claudia Corson, Seattle Drainage and Wastewater Utility). Brown and Caldwell, Seattle, WA. Novotny, V. and G. Chesters. 1981. Handbook of nonpoint pollution, sources and management. Van Nostrand Reinhold, New York, NY. Olivas. 1995. September 20, 1995. Personal communication (phone conversation with Beth Schmoyer, Herrera Environmental Consultants). Tukwila Fire Department, Tukwila, WA. Oregon Department of Environmental Quality. 1978. Hazardous waste: A fact sheet for Oregonians. Solid Waste Division, Salem, OR (as cited by Ridgley and Galvin 1982). Perteet. 1993. Southgate Creek basin study: Draft detention analysis report. Prepared for Tukwila Department of Public Works by Perteet Engineering, Inc., Everett, WA. Pitt, R., M. Lalor, D.D. Adrian, R. Field, and D. Barbe'. 1993. Investigation of inappropriate pollutant entries into storm drainage systems, a user's guide. EPA 600/R-92/238. U.S. Environmental Protection Agency, Office of Research and Development, Risk Reduction Engineering Laboratory, Cincinnati, OH. Puget Sound Water Quality Authority. 1986. 1986 Puget Sound water quality management plan. Puget Sound Water Quality Authority, Olympia, WA. Puget Sound Water Quality Authority. 1991. 1991 Puget Sound water quality management plan. Puget Sound Water Quality Authority, Olympia, WA. 335/plan 70 Herrera Environmental Consultants Reinelt, L. and R.R. Horner. 1990. Characterization of the hydrology and water quality of palustrine wetlands affected by urban stormwater. Prepared for the Puget Sound Wetlands and Stormwater Management Research Program. King County Resource Planning, Seattle, WA. Ridgley, S.M. and D.V. Galvin. 1982. Report of the household hazardous waste disposal project, Metro Toxicant Pretreatment Program Report #1. Municipality of Metropolitan Seattle. U.S. EPA. 1973. A technical and economic study of waste oil recovery, Part II, Investigation of sources. EPA 530 -SW -90. U.S. Environmental Protection Agency, Solid Waste Division, Washington, D.C. (as cited by Ridgley and Galvin 1982): U.S. EPA. 1983. Results of the nationwide urban runoff program. Volume 1. Final report. U.S. Environmental Protection Agency, Water Planning Division, Washington, D.C. Versar. 1988. Retention, detention, and overland flow for pollutant removal from highway stormwater runoff, Interim guidelines for management measures. FHWA/RD-87/056. Prepared for Federal Highway Administration by Versar, Inc., Springfield, VA. Wanielista, M.P. and Y.A. Yousef. 1993. Stormwater management. John Wiley and Sons, Inc., New York, N.Y. 335/plan 71 Herrera Environmental Consultants APPENDIX A Figures FIGURES (APPENDIX A) 1 Southgate Creek drainage basin. 2 Southgate Creek stream reaches identified for watercours rating. 3 Land use in the Southgate Creek drainage basin. 4 Businesses operating in the Southgate Creek basin. 5 Sampling stations at the Fostoria Park Industrial Center. 6 Sampling stations in Southgate Creek. 7 Comparison of flow in Southgate Creek tributaries. 8 Comparison of pH data in Southgate Creek. 9 Comparison of dissolved oxygen concentrations in Southgate Creek samples. 10 Comparison of fecal coliform bacteria numbers in Southgate Creek samples. 11 Septic system failures in the Southgate, Creek basin. 12 Comparison of dissolved copper concentrations in Southgate Creek samples. 13 Comparison of dissolved lead concentrations in Southgate Creek samples. 14 Comparison of dissolved zinc concentrations in Southgate Creek samples. \PG. S ,27 St S 133 St S 135 St S 128 St S 138 St S 142 St S 144 St • 11 11 S 126 St\\ S 140 St S 130 St Fork Nltdd1e .�'�` S 141 St S 143 St Southgate Park ?S148St 908 r S 136 St S 137 St S 144 St Foster Golf Course N St. Thomas Church Foster High School S 146 St ro D ti) S 148 St S 136 St 1 137 St S 139 St 5 140 St Showalter Junior High School 00 4 0 8 0 0 1 2 SCALE: 1' = 400' 0' D 1. LEGEND — — Ditch/Stream Pipe Manhole Catch Basin Culvert Drainage Basin Boundary HERRERA FOSTORIA STORMWATER ' QUALITY MANAGEMENT PLAN Figure 1. Southgate Creek drainage basin map. \13°. S 127 St 1 S 128 St Highllne Specialty Center 11 II S126st\\ 1 CcD 1 CA S 130 St 0 S 133 St S 135 St Southgate Park S 136 St S 137 St Foster Golf Course S 138 St 137 St S 140 St S 141 St S 142 St D St. Thomas Church v! �S143St Foster High School Showalter Junior High School S 144 St S 146 St 0 S 148 St Fl �► ll D 0 S 148 St D N 200 00 800 0 1 2 SCALE: 1' 400' S 1. ut D T LEGEND Ditch/Stream Pipe • Manhole • Catch Basin Culvert Drainage Basin Boundary 15-1 Stream Reach Designation For Watercourse Ratings HE RRRRERA FOSTORIA STORMWATER' QUALITY MANAGEMENT PLAN Figure 2. Southgate Creek stream reaches identified for watercourse rating. = Southgate Creek LEGEND — — Basin boundary Ditch/stream Pipe EE ' Light Industry Commercial Multifamily residential Park Public facilities Transportation corridor Single family residential 1000 2000 FEET APPROXIMATE SCALE S. 135th St. S. 137th St S. 140th St S. 144th St Figure 3. Land use in the Southgate Creek drainage basin. HERRERA V4ME C \721°. S 12 St S 133 St S 135 St S 128 St Highllne Speclaity Center S 138 St S 142 St S 144 St 11 1► S 126 St\\ S 140 St 5 130 St Fork i5143St S 141 St Southgate Park S 736 St 5 136 St S 137 St S 144 St 137 St S 139 St y St. Thomas Church Foster High School S 148 St i 5 140 St Showalter Junior High School Foster Golf Course 1. S 146 St of S 148 St O 200 4 0 800 O 1 2 SCALE: 1" = 400' D N LEGEND Ditch/Stream Pipe • Manhole • Catch Basin Culvert Drainage Basin Boundary 12 Business Location (See Table C-1) HERS FOSTORIA STORMWATER' QUALITY MANAGEMENT PLAN Figure 4. Businesses operating in the Southgate Creek drainage basin. a S. 133rd STREET SW -12 (500' Downstream) SW -11 • SW -11 (250' Downstream) Sw-1o•\ SW -8 SW -�•• Drainage Ditch (No Outlet) SW -9 \••SW -7 SW -7 SW -6 W-10 SW -8 SW -6 SW -5 MW -4• MW -1 \\ 4 MW -2 Legend MW -7 p� SW -4 YY„ SW SW -3 � SW -3 `•, SW -2 SW -1 • MW -5 MW -3 Q• MW -1 Monitoring well • SW -10 Surface water sampling station Soil sampling station Source: Earth Consultants (1993) 0 MW -6 SW -2 (74' Upstream) SW -1 (200' Upstream) Approximate Scale 50 100 200ft. Figure 5. Sampling stations at the Fostoria Park Industrial Center. A-5 Southgate Creek LEGEND • Water sampling station - - Basin boundary Ditch/stream Pipe 0 1000 2000 FEET APPROXIMATE SCALE S. 135th St S. 139th St. S. 140th St S. 144th St. S. 146th St. S. 1486 St. Figure 6. Sampling stations in Southgate Creek. HERRERALA mMECONSULUNTS 1,000 900 800 700 600 500 400 300 200 100 1,454 O Summer base Winter base ■ Winter storm 1,018 3,271 North/Middle Fork South Fork Central Drain Figure 7. Comparison of flow in Southgate Creek tributaries. East Drain Near Outfall Ditch behind industrial park on S. 134th St. WQDAT.XLS flow b co 10.00 9.00 8.00 7.00 6.00 2. 5.00 --- 4.00 --- 3.00 2.00 1.00 0.00 O Summer base O Winter base ■ Winter storm Class A Water Quality Std. North/Middle Fork South Fork Central Drain Figure 8. Comparison of pH data in Southgate Creek. East Drain Near Outfall Ditch behind industrial park on S. 134th St. WQDAT.XLS pH 14 12 10 issolved • xygen (m./L, O Summer base ©Winter base ■ Winter storm North/Middle Fork South Fork Central Drain East Drain Near Outfall Figure 9. Comparison of dissolved oxygen concentrations in Southgate Creek samples. Ditch behind industrial park on S. 134th St. Water Quality Std. = 8.0 WQDAT.XLS do 3,000 2,500 j 2,000 r R 1,500 m 0 U iv 1,000 is - O Summer base ©Winter base ■Winter storm Water Quality Std. North/Middle Fork South Fork Central Drain East Drain Near Outfall Figure 10. Comparison of fecal coliform bacteria numbers in Southgate Creek samples. Ditch behind industrial park on S. 134th St. WQDAT.XLS fc i \13°. S 127 St S 128 St, I II 5 126 St\\ 1 o }� 1 N a S 130 St r � 4p, i� • iff 14 Highllne Specialty Center • S 131 St • • • le S 133 St S 135 St 5166 St • S 1j7•5t Foster Golf Course S 136 St 5 138 St • S 140 St 5 140 St S 141 St S 142 St • • • • N / • • • • ?S148St nI Ii 5143 St S 144 St Foster High School Showalter • Junior High • School • S 1• S 146 St S 148 St ami O 200 400 800 O 1 2 SCALE: 1' s 400' N v D fn LEGEND Ditch/Stream Pipe • Manhole • Catch Basin Culvert Drainage Basin Boundary • Septic System Failure C --i Hf� RRRfRA FOSTORIA STORMWATER QUALITY MANAGEMENT PLAN Figure 11. Septic system failures,in the Southgate Creek drainage basin. A-1 Dissolved Copper (ug!L) 3.5 2.5 1.5 Water Quality Std = 7 ug/L T o Summer base Winter base IN Winter storm 0.5 -- North/Middle Fork South Fork Central Drain East Drain Near Outfall Figure 12. Comparison of dissolved copper concentrations in Southgate Creek samples. Ditch behind industrial park on S. 134th St. WQDAT.XLS disscu Water Quality Std =1 ug/L <1 isso ved Lea • (u•/L, <1 <1 O Summer base O Winter base ■Winter storm <1 <1 North/Middle Fork South Fork Central Drain East Drain Near Outfall Figure 13. Comparison of dissolved lead concentrations in Southgate Creek samples. Ditch beind indusstrial park on S. 134th St. WQDAT.XLS disspb = — Dissolved Zinc (ug/L) 60 Water Quality Std =62-180 ug/L T 50 40 30 20 10 D Summer base ®Winter base ■ Winter storm North/Middle Fork South Fork Central Drain East Drain • Near Outfall Figure 14. Comparison of dissolved zinc concentrations in Southgate Creek samples. Ditch behind industrial park on S. 134th St. WQDAT.XLS disszn \Pe. S 127 St 1 S 128 St S 130 St Hlghllne Specialty Center S 133 St S 135 St 5 136 St S 137 St Foster Golf Course S 138 St S 139 St S 140 St 5 140 St 5 142 St S 142 ISt 4. 4. D St. Thomas Church Foster High School S 144 St Showalter Junior High School N U D Vl A D co (n n1 11 5 144 St S 146 St N S 148 St U a1 D S 147 O 200 400 800 O 1 2 SCALE: 1' v 400' s 1. D A u! IF LEGEND Ditch/Stream Pipe • Manhole o Catch Basin Culvert Drainage Basin Boundary Project Description: Project 1: Project 2: Project 3: Project 4: Project 5: Project 6: Project 7: Project 8: Project 9: Project 10: Project 11 a: Project 11 b: Project 12: Project 13: Project 14: Project 15: Project 16: Project 17: Sediment trap at S 135th St High-flow bypass at S 133rd St Sediment trap at 48th Ave S High-flow bypass at 48th Ave S Modify ditch on Interurban Ave S Sediment trap at 40th Ave S Stabilize north fork above 40th Ave S Extend culvert at 40th Ave S Stabilize middle fork above 40th Ave S Detention ponds at 40th Ave S and S 133rd St Stabilize south fork below 40th Ave S Extend culvert under SR -99 High-flow bypass at S 133rd St Improvechannel below S 133rd St Improve channel below S 133rd PI Improve WDOT ditch along SR -599 Detention facilities in upper basin Upper basin High-flow bypass at SR -99 • • • Potential bypass route c-� H RRERA FOSTORIA STORMWATER , QUALITY MANAGEMENT PLAN Figure 15. Stormwater quality improvement alternatives. APPENDIX B Tables TABLES (APPENDIX B) 1 Watercourse ratings for streams in the Southgate Creek basin. 2 Land use in the Southgate Creek basin. 3 Southgate Creek base flow sampling results from 1991 study. 4 Southgate Creek storm flow sampling results from 1991 study. 5 Results for pH in surface and ground water samples collected from the Fostoria Industrial Park Center. 6 Spills reported in The Southgate Creek basin, 1991-1995. 7 Washington state water quality standards for class a freshwaters. 8 Results from summer base flow samples collected in Southgate Creek. 9 Results from winter base flow samples collected in Southgate Creek. 10 Results from winter storm flow samples collected in Southgate Creek. 11 Comparison of southgate creek water quality data with data from other urban areas in Puget Sound. 12 Detention requirements for the upper Southgate Creek basin. 13 Summary of estimated costs for stormwater quality improvement alternatives. 14 Comparison of stormwater quality improvement alternatives. Table 1. Watercourse ratings for streams In the Southgate Creek basin. Watercourse Number` Drainage Location Watercourse Rating° INSTREAM ELEMENTS STREAM CORRIDOR FEATURES' Watercourse Channel Channel Width Capacity Stability Fish Use Fish Habitat Width of umaintained Vegetation vegetation Diversity Corridor Barrier Function Surrounding Land Use 15-1A East drain Macadam Rd to S. 136th St. 1 2 0 2 1 1 3/3 3/3 3/3 2/2 15-1B East drain S. 136th St. to 48th Ave. S 3 2 1 1 1 1 1/1 2/2 1/1 1/1 15-1C East drain -Southgate Cr. 48th Ave. S. to S. 133rd PI. 3 2 1 1 2 1 1/0 1/0 0/0 -1/-2 15-1D Southgate Cr. S. 133rd St. to S. 133rd PI 2/3 3 0 -1 1 1 1/3 1/2 2/2 1/2 15-2A Central drain S. 140th St. to S. 139th St. 2 2 3 -1 0 0 3/3 3/3 2/2 -1/-1 15-2B Central drain S. 139th St. to S. 137th St. . 3 2 1 0 0 0 2/1 2/0 1/0 -1/-1 15-2C Central drain S. 137th St. to S. 135th St. 1 2 2 -1 1- 1 3/3 3/3 3/3 3/3 15-2D Central drain S. 135th St. to S. 133rd St 3 2 2 -1 0 0 1/1 2/1 2/2 -1/-2 15-3A North fork SR -99 to 40th Ave. S. 3 2 1 -1 0 0 2/2 2/2 2/2 -1/-1 15-3B North fork 40th Ave. S. to 100ft downstream 3 2 1 0 0 0 0/0 0/0 0/0 -1/-1 15-3C North fork 40th Ave. S. to S. 133rd St. 3 2 0 -1 0 0 2/2 2/2 3/3 -1/-1 15-4A South fork SR -99 to 40th Ave. S. 2 3 1 -1 0 0 3/3 3/3 2/2 -1/-1 15-4B South fork 40th Ave. S. to S. 133rd St. 3 3 0 -2 0 0 1/3 1/2 1/1 -1/-1 15-5A Middle fork SR -99 to 40th Ave. S. 2 3 1 2 0 0 3/3 3/3 2/2 3/3 15-5B Middle fork 40th Ave. S. to North Fork 3 2 2 1 0 0 1/1 2/2 2/2 -1/-1 15-6 Southgate Cr. 300 ft upstream of SR -599 2 2 1 2 2 1 2/3 2/2 2/2 -1/-2 (a) Left bank/right bank (b) 1 = High habitat value; 2 = Moderate habitat value; 3 = Low habitat value. (c) See Figure 2. Watercourse width: > 5 ft = 3; 1 to 5 ft = 2; <1 ft = 1 Channel capacity: Ample, no overbank = 3; Adequate, some overbank = 1; Insufficient, overbank common = 0 Channel stability: No scour or downcutting = 3; Slight scour (<25%) = 1; Moderate scour (25-50%) = 0; Obvious scour = 0 Fish use: Salmonids present = 3; Potential for migratory salmonid = 2; Potential for stocked salmonid = 1; No potential for salmonid, little potential for restoration = 0 Fish habitat: Spawning, rearing, and overwintering = 3; Two of three habitat types = 2; Rearing or overwintering = 1 Width of unmaintained vegetation: > 50 ft = 3; 25 to 50 ft = 2; 5 to 25 ft = 1 Vegetation diversity: High diversity, mulit-layered = 3; Open forest or shrub with understory = 2; Single layer with low diversity =1 Corridor barrier function: Dense forest or shrub (100 to 75%) = 3; Dense forest or shrub (50 to 75%) = 2; Dense forest or shrub (25 to 50%) = 1 Surrounding land use: Forested = 3; Shrub or unmaintained grassland = 2; Active agriculture or pasture = 1; urban (residentiallawn) = -1; urban (industrial/commercial) = -2 Reference: Jones and Stokes (1990) WCRAT.XLS Herrera Environmental Consultants Table 2. Land use in the Southgate Creek basin. Land Usea South Fork Middle Fork North Fork Central Drainb East Drainb Lower Basin` Total Single family residential 111.5 6.7 41.6 51.2 . 35 30.5 276.5 Multi -family residential 15.1 1.4 . 0 0 0 0 16.5 Commercial 72.5 0 0 7.9 7.2 0 87.6 Forest/open 21.1 3.7 0.9 3.1 27.4 0 56.2 Grass/open 0 0 0 12.1 15 33.7 60.8 Light industrial 0 0 . 0 5.1 14.5 14.5 34.1 Highway 10.1 1.4 1.5 0 0 14 27 Total 230.3 13.2 44 79.4 99.1 92.7 558.7 (a) Land use reported in acres. (b) Commercial land use includes schools and other public facilities. (c) Below S 133rd Street. LANDUSE.XLS Herrera Environmental Consultants Table 3. Southgate Creek base flow sampling results from 1991 study.' Station F Station C-2 Station H Temperature (°C) pH (standard units) Dissolved oxygen (mg/L) Specific conductance (pmhos/cm) 11.95 6.89 9.90 0.20 11.65 7.89 9.36 0.237 11.45 7.97 9.63 2.24 a Source: KCM (1992). Table 4. Southgate Creek storm flow sampling results from 1991 study.' Station H Station C-2 Metals (pg/L) Cadmium <2 <2 Copper 11.8 10.4 Zinc 44 41 Nutrients (pg/L) Ammonia <10 <10 Total phosphorus 750 650 Soluble reactive phosphorus 9 3 Biochemical oxygen demand (mg/L) 4.56 4.30 Chemical oxygen demand (mg/L) 22.2 17.9 Fecal coliform bacteria (cfu/100 mL)" >2,960 • >6,520 a Source: KCM (1992). b cfu: colony forming unit. 335/appx-b B-3 Herrera Environmental Consultants Table 5. Results for pH in surface and ground water samples collected from the Fostoria Industrial Park Center. Surface Water Samples Station 1990 1993 Ground Water Samples Station 1990 1993 SW -1 7.6 6.6 MW -1 12.67 NA SW -2 7.6 7.37 MW -2 12.47 12.02 SW -3 8.51 7.71 MW -3 12.21 12.73 SW -4 8.6 8.26 MW -4 6.43 6.53 SW -5 9.26 9.07 MW -5 6.7 6.71 SW -6 8.3 9.84 MW -6 11.84 11.26 SW -7 9.0 9.06 MW -7 12.75 12.89 SW -8 9.7 8.17 SW -9 7.2 7.55 SW -10 6.65 9.34 SW -11 8.45 8.8 SW -12 8.31 NA NA = Not analyzed Source: Earth Consultants (1990); Martin and Moreno (1993 pers.comm.). FOSIPARK.XLS ph B-4 Herrera Environmental Consultants = - Responsible Party Spill Location ID No. Date Material Quantity Media Source Unknown Boeing Tukwila plant Boeing Tukwila plant Metro bus station McLees Distributing Unknown Unknown Unknown Larry's Market Metro Pump Station Unknown Unknown Unknown Unknown Unknown 12855 48th Ave. S. Building 2-49 12100 E. Marginal Way S. 4585 S. 134th Place Off Interurban Ave. where 43rd Ave bridge crosses Duwamish River. On Interurban south of S. 133rd, in front 8220 of Unocal station. Northbound Hwy 599 at offramp to 8924 5/28/92 Interurban Corner of 144th Ave. S and Pacific Hwy 9851 S. 13701 Interurban S. 11979 Driveway at 13718 Macadam Rd S.side 12450 of bank under 1-5 bridge. Off 1-5 at 48th Ave. S. and Interurban 5278 6774 6856 7720 7821 7947 7/17/91 11/7/91 11/14/91 2/12/92 2/21/92 3/3/92 Oil/petroleum Oil/petroleum Hydrofluoric acid Oil/petroleum Oil/petroleum Oil/petroleum 3/23/92 Oil/petroleum 14060 Interurban S. 13400 Interurban Bridge near Foster Golf Course Oil/petroleum 8/4/92 Food waste 3/22/93 Sewage/sludge 5/6/93 Paint/thinner 12643 5/27/93 Unknown corrosive: pH = 14. 13229 8/1/93 Transformer/mineral oil 16275 6/10/94 Sand • 17056 9/4/94 Oil/petroleum 15 gallons 30 gallons 1 gallon Unknown Quarts Unknown 1-2 gallons 25 gallons Unknown Unknown (20) 5 gallon buckets 2 gallons 5-10 gallons Unknown Unknown Storm drain Surface water Building Surface water Surface water Surface water Soil Illegal dumping Tank overflow Leaking containers Leaking UST Drum storage area Unknown --sheen on water. Unknown --motor oil Soil Auto/truck accident Surface water Surface water Soil Roadway Surface water Surface water Surface water Leakage from trash compactor.. Plant overflow Illegal dumping Illegal dumping Truck/transformer collision. Debris from bridge repair work. Sheen—surface runoff. UST = underground storage tank. SPILLS.XLS Herrera Environmental Consultants Table 7. Washington state water quality standards for Class A freshwaters.' Parameter Standard Fecal coliform bacteria Shall not exceed a geometric mean value of 100 organisms/100 mL, with not more than 10 percent of samples exceeding 200 organisms/100 mL.° Dissolved oxygen Shall exceed 8.0 mg/L. Total dissolved gas Shall not exceed 110 percent saturation at any point of sample collection. Temperature Shall not exceed 18.0°C due to human activities. When natural conditions exceed 18°C, no temperature increase will be allowed which will raise the receiving water temperature by greater than 0.3°C. Incremental temperature increases from nonpoint source activities shall not exceed 2.8°C. pH Shall be within the range of 6.5 to 8.5 with a human -caused variation within a range of less than 0.6units. Turbidity Shall not exceed 5 NTU over background turbidity when the background turbidity is 50 NTU or less, or have more than a 10 percent increase in turbidity when the background turbidity is more than 50 NTU. Toxic, radioactive, or Shall be below concentrations which have the potential either singularly deleterious material or cumulatively to adversely affect characteristic water uses, cause acute concentrations or chronic conditions to the most sensitive biota dependent on those waters, or adversely affect public health, as determined by the department. . Aesthetic values Shall not be impaired by` the presence of materials or their effects, excluding those of natural origin, which offend the senses of sight, smell, touch, or taste. Characteristic uses Shall include, but not be limited to, the following: domestic, industrial, and agricultural water supply; stock watering; salmonid and other fish migration, rearing, spawning, and harvesting; shellfish rearing; spawning, and harvesting; wildlife habitat; general recreation and aesthetic enjoyment; and commerce and navigation. a Source: WAC 173-201A n Reported as colony -forming units per milliliter (cfu/mL). Abbreviations: mL milliliters mg/L milligrams per liter NTU Nephelometric turbidity units 335/appx-b B-6 Herrera Environmental Consultants - Table 8. Results from summer base flow samples collected In Southgate Creek. Samples collected September 19, 1994. > = greater than U = Undetected at value shown. cfu = colony -forming unit. TPH = Total petroleum hydrocarbons. Does not meet state water quality standard for Class A waters: Fecal coliform bacteria: geometric mean of 100 cfu/100 mL or no more than 10 percent of all samples above 200 cfu/100 mL. Dissolved oxygen: greater than 8.0 mg/L. pH: Between 6.5 and 8.5. Exceeds state water quality standard for chronic toxicity (metals). Exceeds state water quality standard for acute toxicity (metals). WQDAT.XLS wqsumbase Herrera Environmental Consultants Station 1 North/Middle Fork Station 2 South Fork Station 3 Central Drain Station 4 East Drain Station 5 Southgate Cr. near Outfall Station 6 Ditch behind industrial park on S. 134th St. Flow (cfs) 0.0598 0.0456 0.0119 0.199 0.146 0.0014 Flow (gpm) 27 20 5 89 66 1 pH 1 341 6.51 6 O0! 863 7.83 r 6 32 Dissolved oxygen (mg/L) 9.0 9.2 9.1 W .7 9.1 Temperature (° C) 17.7 15.5 15.1 16.2 16.8 _3.8 16.7 Total suspended solids (mg/L) 9.5 1.2 3.8 8.4 1.2 38 Conductivity (umho/cm) 120 368 310 391 267 415 Turbidity (NTU) - 2.5 1.1 2 2.6 1.4 8 Hardness (mg/L as CaCO3) 85.2 176 186 164 200 214 Fecal coliform bacteria (cfu/100 mL) :_ -1;"066' > , 1,060 > . _2,3b0,> _, ,1,200j> - 1,20 '> 1,40> Total phosphorus (ug/L) 37 94 88 149 __ _ 78 _ 189 Soluble reactive phosphorus (ug/L) 33 94 109 136 72 73 , Dissolved copper (ug/L) 1 U 1 U 1 U 1 U 1 U 1 U Dissolved lead (ug/L) 0.5 U 0.5 U 0.5 U 0.5 U 0.5 U 0.5 U Dissolved zinc (ug/L) 3 U 8 3 U 3 U 3 U 6 TPH (mg/L) 0.25 U _ 0.25 U 0.25 U 0.25 U 0.25 U 0.25 U Samples collected September 19, 1994. > = greater than U = Undetected at value shown. cfu = colony -forming unit. TPH = Total petroleum hydrocarbons. Does not meet state water quality standard for Class A waters: Fecal coliform bacteria: geometric mean of 100 cfu/100 mL or no more than 10 percent of all samples above 200 cfu/100 mL. Dissolved oxygen: greater than 8.0 mg/L. pH: Between 6.5 and 8.5. Exceeds state water quality standard for chronic toxicity (metals). Exceeds state water quality standard for acute toxicity (metals). WQDAT.XLS wqsumbase Herrera Environmental Consultants Table 9. Results from winter base flow samples collected in Southgate Creek. E = Estimated. U = Undetected at value shown. cfu = colony -forming unit. TPH = Total petroleum hydrocarbons. ®Does not meet state water quality standard for Class A waters: Fecal coliform bacteria: geometric mean of 100 cfu/100 mL or no more than 10 percent of all samples above 200 cfu/100 mL. Dissolved oxygen: greater than 8.0 mg/L. pH: Between 6.5 and 8.5. Exceeds state water quality standard for chronic toxicity (metals). Exceeds state water quality standard for acute toxicity (metals). WQDAT.XLS wqwinbase Herrera Environmental Consultants - Table 10. Results from winter storm flow samples collected in Southgate Creek. • Station 1 North/Middle Fork Station 2 South Fork Station 3 Central Drain Station 4 East Drain Station 5 Southgate Cr. near Outfall A B Station 6 Ditch behind industrial park on S. 134th St. Flow (cfs) Round 1 0.17 0.55 0.33 0.67 1.00 . 0.85 0.11 Round 2 0.19 0.44 0.14 0.49 0.63 0.55 0.054 Round 3 0.31 1.34 0.11 0.56 0.67 1.54 0.12. Round 4 0.22 0.91 0.35 0.55 0.90 1.15 0.08 Average 0.9 3.2 0.9 2.3 3.2 7.3 0.4 pH 7.38 7.71 7.64 : 8.98) _ 78_93 7.30 7.12 Dissolved oxygen (mg/L) 11.70 11.60 12.05 10.5 10.8 9.3 7 85 Temperature (° C) 6.8 7.5 7.0 9.0 9.8 8.9 9.0 Total suspended solids (mg/L) 14 13 16 16 18 11 Conductivity (umho/cm) 158 170 172 213 206 157 Turbidity (NTU) 12 11 11 22 12 12 Hardness (mg/L as CaCO3) 60.6 74.9. 62.8 77.5 79.5 62.2 Fecal coliform bacteria (cfu/100 mL) 1;8001 E _ :274001 E 3,0001 E 2,6600E 2,000' [ 7,000• , E 22 E Total phosphorus (ug/L) 94 73 90 142 117 111 Soluble reactive phosphorus (ug/L) 48 33 51 57 59 36 Dissolved copper (ug/L) 3.4 3.5 1.8 3.6 2 3.7 Total copper (ug/L) 8.7 8.6 4 12.6 7.4 8.7 Dissolved lead (ug/L) 1 U 1 U 1 U 1 U 1 U 1 U Total lead (ug/L) 6.5 5.7 2.1 9.7 6.6 5.7 Dissolved zinc (ug/L) 6 7 3 U 3 U 3 32 Total zinc (ug/L) 26 32 12 51 32 116 TPH (mg/L) 0.25 U _ 0.25 U 0.25 U 0.25 U 0.25 U 0.25 U 0.25 U Samples collected March 8, 1995. 0.58 inches of rain measured at Seattle -Tacoma International Airport on March 8, 1995. E = Estimated. U = Undetected at value shown. cfu = Colony -forming unit. TPH = Total petroleum hydrocarbons. (T' Does not meet state water quality standard for Class A waters: Fecal coliform bacteria: geometric mean of 100 cfu/100 mL or no more than 10 percent of all samples above 200 cfu/100 mL. Dissolved oxygen: greater than 8.0 mg/L. pH: Between 6.5 and 8.5. . Exceeds state water quality standard for chronic toxicity (metals). , Exceeds state water quality standard for acute toxicity (metals). WQDAT.XLS wqwinstorm Herrera Environmental Consultants Table 11. Comparison of Southgate Creek water quality data with data from other urban areas in Puget Sound. cfu = colony forming units. Note: First line is the range in concentrations, second line is the geometric mean. (a) Data from 2 drainage basins tributary to Lake Washington (Herrera 1994b). (b) Data from urban areas in Seattle (Merrill 1989 pers. comm.). (c) Data from two highly urbanized drainage basins in King County (Reinelt and Horner 1990). COMP.XLS data Herrera Environmental Consultants Table 12. Detention requirements for the upper Southgate Creek basin. Possible detention site 2 -year peak flow (cfs) 10 -year peak flow (cfs) Required Detentions () Dead Storage (ft3)'' Pre- development Existing Pre -Existing development King County (1990)° Ecolo gy draft King County (1995)d North forke 35th Avenue S 0.6 3 1.4 5.1 27,000 9,100 25,000 28,700 37th Avenue S 0.8 4.3 2.1 7.4 45,000 16,000 45,000 50,500 Middle forks 1.3 1.7 3.3 2.6 1,500 6,200 15,000 17,600 South fork 38th Avenue Se 0.2 1.6 0.5 2.7 29,000 5,400 15,300 17,300 S 140th Streets 0.7 6.1 1.9 10.3 152,000 25,000 70,000 79,300 S 144th Streets 0.6 4.6 1.4 7.5 114,000 21,000 54,000 62,100 south of S 144th Streets _ 2.6 21.5 6.2 34.4 270,000 71,000 180,00Q 208,600 (a) Sized according to King County (1990). standards including 30 percent safety factor. (b) King County (1990) design standards: 0.33 of 2 -year, 24-hour storm. (c) Ecology (1992) design standards: 0.64 of 2 -year, 24-hour storm. (d) draft King County (1995) design standards: Vb/V, = 3.0. (e) Does not include contributions from SR -99. (f) Includes runoff from 1.4 acres of SR -99. (g) Assumes runoff from area south of S 144th Street drains to storm drain under SR -99. Includes runoff from 3.2 acres of SR -99. (h) Dead storage for water quality treatment. USFDET.XLS Herrera Environmental Consultants Table 13. Summary of estimated costs for stormwater quality improvement alternatives. Capital Improvement Projects: Project Cost Central drain 1. Sediment trap at S 135th Ste 2. High flow bypass at S 133rd St East drain 3. Sediment trap at 48th Ave Se.s 4. High flow bypass at 48th Ave Ss 5. Modify ditch on Interurban Ave S North fork 6. Sediment trap at 40th Ave Se 7. Stabilize channel above 40th Ave S Middle fork 8. Extend culvert at 40th Ave S 9. Stabilize channel above 40th Ave S South fork 10. Detention ponds at 40th Ave S and S 133rd Stb 1la. Stabilize channel below 40th Ave S 11b. Extend 12 -inch culvert under SR -99 Lower Southgate Creek 12. High flow bypass at S 133rd St 13. Improve channel below S 133rd Se 14. Improve channel below S 133rd Place 15. Improve WDOT ditch along SR -599 Upper Southgate Creek 16. Detention facilities in upper basin` 17. High flow bypass at SR -99 $48,000 $45,000 $41,000 $277,000 $13,000 $39,000 $38,000 $14,100 $38,000 $319,000 $210,000 $17,000 $292,000 $140,000 $55,000 $190,000 $654,000 $1,719,000 COST.XLS summ Water Quality Programs: Program Element Cost Basisd Cost Mapping/inventory Storm drain maintenance Public system procedures Private system requirements Catch basin cleaning S 134th Street sediment removals Water quality functions Illicit connection survey Drainage plan review Technical assistance program Information dissemination Community-based protects Storm drain stenciling Stream cleanup LS $12,000 LS A A LS LS A -.A A $10,000 $21,000 $15,000 $39,000 $20,000 $3,000 $26,000 $3,000 A $4,000 A $4,000 (a) Costs based on sizing according to King County (1990) standards: 0.33 of 2 -year, 24-hour storm event. (b) Costs updated from Perteet (1993) plus addition of 3 feet of dead storage for water quality treatment/sediment storage: (c) Costs assume detention pond with wet pond for water quality treatment. Sizing based on King County (1990) standards. Land purchase cost not included. (d) LS = lump sum cost A = annual cost. (e) Part of Fostoria storm drain projectalready on the Surface Water Utility's list of recommended CIPs. (f) Cost includes replacing culvert S 133rd Place. Without culvert replacement, project cost is about $76,000. Herrera Environmental Consultants Ease of Plan Elements Effectivenessa Implementationb Cost` Mapping/inventory Storm drain maintenance Public system procedures Private system requirements Catch basin cleaning S 134th St. sediment removal Water quality position/program Illicit connection survey Drainage plan. review Technical assistance program Information dissemination Community-based projects Storm drain stenciling Stream cleanup 2 2 2-3 1-2 2 2 3 2 2 2 3 3 3 1-2 2 2 3 3 2 3 3 2 1-3e 2 2 3 2 3 3 3 3 3 (a) 1 = low effectiveness, 3 = high effectiveness. (b) 1 = difficult to implement, 3 = easy to implement. (c) 1 = high cost (>$100,000), 3 = low cost ($20,000). (d) Part of Fostoria storm drain project which is already included on the Surface Water Utility's list of recommended CIPs. Cost assumes sediment trap can be installed above ground. (e) Range reflects options for achieving more frequent catch basin cleaning. High cost (1) associated with purchase of a new vactor truck. Low cost (3) for modifying maintenance crew schedules to increase cleaning frequency. Herrera Environmental Consultants APPENDIX C Business Inventory Table C-1. Businesses operating in the Southgate Creek basin, sorted by map number. MAP COUNT NO. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 30 24 40 25 42 26 43 27 44 28 47 29 48 30 51 31 60 32 62 33 23 34 46 35 49 1 FARWEST PAINT MFG CO2 1 SOUND OVERHEAD DOOR SUPPLY (SDS) 1 IRON DESIGN CENTER 1 A&E MACHINE2 1 STRUCTURAL INSTRUMENTATION INC1'2 1 MCLEES DISTRIBUTING 1 A-1 USED TIRES 1 AMERICAN TIRE WHOLESALERS 1 7 -ELEVEN STORE 2307-22866 1 WASHINGTON CARS 1 UNITED MOTORS 1 AUTOS UNLIMITED 1 SEATTLE TRUCK AND TRACTOR 1 BP GAS 1 GASAHOL 1 FLAGSHIP CLEANING SERVICE INC 1 R 8 S AUTO CARE 1 ENGINE OVERHAUL 1 SEATAC CAR WASH 1 STAR NURSERY 1 ACE CONSTRUCTION & LANDSCAPING 1 MALONE'S LANDSCAPE CONTRACTING 1 FOSTORIA PARK INDUSTRIAL CENTER 1 HOLADAY PARKS INC 1 WASHINGTON MECHANICAL CONTR. 1 BR ROOFING 1 BOW LAKE CABINET SHOP 1 US BEARINGS & DRIVES 1 BIG WHEEL AUTO PARTS 1 SEATAC MOTORS 1 POWER ENGINEERING 1 BRENNAN HEATING CO 1 HEALTHCO INTERNATIONAL 2 OLYMPIC POSTER CO 2 ELECTRICAL INSULATION SUPPLIERS INC 4522 S 133RD 4451 S 134TH PLACE 3450 S 148TH ST 4712 S 134th 4611 S 134TH PLACE 4585 S 134TH PLACE 14004 PACIFIC HGWY S 4435 S 134TH PLACE 14207 PACIFIC HWY S 14607 PACIFIC HGWY S 13911 PACIFIC HGWY S 14661 PACIFIC HGWY S 14626 MILITARY RD S 14415 PACIFC HGWY S 14002 PACIFIC HGWY S 4455 S 134TH ST 14612 MILITARY RD S 14004 PACIFIC HGWY S 14224 PACIFIC HGWY S 13916 42ND S 4446 S 131st PLACE 13130 44TH S TUKWILA S 133RD AND S 134TH STS TUKWILA 4650 S 134TH PLACE 13800 PACIFIC HGWY S 13750 PACIFIC HGWY S 3456 S 148TH 12620 INTERURBAN S 14013 PACIFIC HGWY S 14120 PACIFIC HGWY S 4487 S 134TH PLACE 4601 S 134TH PLACE 4550 S. 134TH ST 4495 S 134TH PL 4475 S 134TH PLACE TUKWILA 19168 244-8844 2851 SEATTLE 19168 248-8300 7699 TUKWILA 98188 622-5980 3466 SEATTLE 19168 244-2146 3599 TUKWILA 19168 244-6100 3829 TUKWILA 19168 242-7129 5531 TUKWILA 98188 5014 TUKWILA 98188 5014 TUKWILA 98188 241-1519 5411 TUKWILA 98188 246-5183 5511 TUKWILA 98188 5511 TUKWILA 98188 244-4200 5511 TUKWILA 98188 241-0500 5511 TUKWILA 98188 5541 TUKWILA 98188 5541 TUKWILA 98188 7218 SEATTLE 98188 743-9634 7538 TUKWILA 98188 7538 TUKWILA 98188 433-1772 7542 TUKWILA 98188 241-2115 0181 TUKWILA 19168 246-4883 5032 19168 243-9946 0782 19168 None TUKWILA 98188 292-1160 1711 TUKWILA 98188 1711 TUKWILA 98188 1761 TUKWILA 98188 2434 TUKWILA 19168 241-1171 3714 TUKWILA 98188 5013 TUKWILA 98188 5511 SEATTLE 19168 242-7025 3053 TUKWILA 19168 248-7900 1711 TUKWILA 98168 244-7232 7699 TUKWILA 19168 246-7433 2759 TUKWILA 19168 241-1010 5063 Paint manufacture Household repair services, general Architectural and ornamental iron Machine shops, jobbing, and repair Measuring and control devices Auto and truck equipment and parts Tires—used Tires—new Grocery store Motor vehicle dealers Motor vehicle dealers Motor vehicle dealers Motor vehicle dealers Automobile service stations Automobile service stations Industrial laundry General automotive repair Automotive repair Automotive services—car wash Nursery Brick, stone, related materials, whsl. Lawn and garden services Business Park Contractor—heating/air-conditioning Contractor—mechanical Contractor—roofing Wood cabinets Motor vehicle parts/accessories Automotive parts Motor vehicle dealers Gasket, packing, sealing mfr. Heating, air conditioning contractor Professional instrument repair Posters Electrical appliances and equipment J BUS.XLS all Page C-1 Table C-1. Businesses operating in the Southgate Creek basin, sorted by map number (continued). MAP COUNT NO. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 36 50 2 GENERAL BUILDING SUPPLY INC 37 53 2 APPLIANCE DISTRIBUTORS 38 55 2 1 HR CLEANER 39 56 2 ACHIEVA PHOTO VR INC 40 57 2 QUALITY RENTALS 41 59 2 FLITE TIME 42 61 2 BIOMARINE TECHNOLOGIES INC. 43 63 2 HYDRAULIC TECH INC 44 64 2 TRUE VALUE HARDWARE 45 65 2 PREFERRED PRODUCTS 46 66 2 CABLE PLUS 47 67 2 WHITTON 48 97 2 NORMED 49 80 3 ALASKA AIR FORWARDING 50 81 3 AMERICAN LOCK & SUPPLY 51 82 3 CLASSIC BEAUTY SUPPLY 52 83 3 DOUGLAS PRINTING & OFFICE SUPPLY 53 84 3 BETTER BEER 54 85 3 STOP BY CORNER 55 86 3 CHINA PAVILION 56 87 3 GOLDEN NUGGETT RESTAURANT INC. 57 88 3 JACK IN THE BOX 58 89 3 SILVER DOLLAR SALOON 59 90 3 WHITE HORSE TAVERN 60 91 3 BARTELL DRUG COMPANY #43 61 92_ 3 B & B CERAMICS 62 93 3 JET INN MOTEL 63 94 3 STAR LIGHT MOTEL 64 95 3 SEATTLE MAILING BUREAU 65 96 3 CONSUMER PROGRAMS INC 66 98 3 KENTUCKY FRIED CHICKEN 4439 S 134TH PLACE 14639 PACIFIC HGWY S MILITARY RD 14216 MILITARY RD S 14604 PACIFIC HGWY S 4491 S 134TH PLACE 4459 S 134TH PLACE 4389 S 133RD 3716 S 144TH 4475 S 134TH 4477 S 134TH 4485 S 134TH 4310 S 131ST PLACE 4443 S 134th PLACE 4304 S 131st PLACE 4453 S 134TH PLACE 14818 PACIFIC HGWY S S 134TH PLACE 14857 PACIFIC HWY S 14855 PACIFIC HWY S 14025 INTERURBAN AVE S 13050 INTERURBAN AVE S 14027 INTERURBAN AVE 14935 INTERURBAN AVE S 14277 PACIFIC HWY S 3747 S 142ND 4385 S 133RD 4455 S 134TH 3742 S 144TH TUKWILA 19168 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 SEATTLE 19168 TUKWILA 19168 TUKWILA 19168 TUKWILA 98188 TUKWILA 19168 TUKWILA 19168 TUKWILA 19168 TUKWILA 19168 TUKWILA 19168 TUKWILA 19168 TUKWILA . 19168 TUKWILA 98188 TUKWILA 19168 SEATTLE 98188 SEATTLE 98188 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 TUKWILA 98188 SEATTLE 98188 TUKWILA 98188 TUKWILA 19168 TUKWILA 98188 TUKWILA 98188 243-9800 433-0771 242-1110 433-5690 439-7588 439-1881 242-0003 242-8228 433-6260 431-3575 242-3684 941-6867 244-8450 246-8545 (619) 571-2561 241-9526 242-2842 431-0085 431-5700 246-5158 5211 Lumber and other building materials 5722 Household appliances 7216 Drycleaners 7221 Photographic studio 7359 Equipment rental 4731 Freight transportation services 8711 Industrial engrs. 5251 Hardware store 4841 Cable and other pay TV services 5912 Drug store and proprietary stores 4512 Air transportation services 5072 Locks and related materials 5087 Beauty parlor equip. and supply 5112 Office supplies 5149 Groceries and related products 5411 Grocery store 5812 Restaurant 5812 Restaurant 5812 Restaurant 5813 Tavem 5813 Tavern 5912 Drug store 5945 Hobby and craft supplies 7011 Hotels and motels 7011 Hotels and motels 7331 Mail services 7389 Miscellaneous business services 5812 Restaurant 1 On Ecology's list of contaminated sites. 2 Issued NPDES stormwater permit. BUS.XLS all Table C-2. Businesses operating in Southgate Creek basin, sorted alphabetically by business name. MAP COUNT NO. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 1 55 2 9 3 4 4 7 5 21 6 56 7 80 8 81 9 8 10 53 11 12 12 92 13 91 14 84 15 48 16 61 17 44 18 14 19 43 20 62 21 66 22 86 23 82 24 96 25 83 26 49 27 18 28 1 29 16 30 59 31 30 32 15 33 50 34 87 35 23 2 1 HR CLEANER 1 7 -ELEVEN STORE 2307-22866 1 A&E MACHINE2 1 A-1 USED TIRES 1 ACE CONSTRUCTION & LANDSCAPING 2 ACHIEVA PHOTO VR INC 3 ALASKA AIR FORWARDING 3 AMERICAN LOCK & SUPPLY 1 AMERICAN TIRE WHOLESALERS 2 APPLIANCE DISTRIBUTORS 1 AUTOS UNLIMITED 3 B & B CERAMICS 3 BARTELL DRUG COMPANY #43 3 BETTER BEER 1 BIG WHEEL AUTO PARTS 2 BIOMARINE TECHNOLOGIES INC. 1 BOW LAKE CABINET SHOP 1 BP GAS 1 BR ROOFING 1 BRENNAN HEATING CO 2 CABLE PLUS 3 CHINA PAVILION 3 CLASSIC BEAUTY SUPPLY 3 CONSUMER PROGRAMS INC 3 DOUGLAS PRINTING & OFFICE SUPPLY 2 ELECTRICAL INSULATION SUPPLIERS INC 1 ENGINE OVERHAUL 1 FARWEST PAINT MFG CO2 1 FLAGSHIP CLEANING SERVICE INC 2 FLITE TIME 1 FOSTORIA PARK INDUSTRIAL CENTER' 1 GASAHOL 2 GENERAL BUILDING SUPPLY INC 3 GOLDEN NUGGETT RESTAURANT INC. 1 HEALTHCO INTERNATIONAL MILITARY RD 14207 PACIFIC HWY S 4712 S 134th 14004 PACIFIC HGWY S 4446 S 131st PLACE 14216 MILITARY RD S 4443 S 134th PLACE 4304 S 131st PLACE 4435 S 134TH PLACE 14639 PACIFIC HGWY S 14661 PACIFIC HGWY S 14277 PACIFIC HWY S S 134TH PLACE 14013 PACIFIC HGWY S 4459 S 134TH PLACE . 3456 S 148TH 14415 PACIFC HGWY S 13750 PACIFIC HGWY S 4601 S 134TH PLACE 4477 S 134TH 14855 PACIFIC HWY S 4453 S 134TH PLACE 4455 S 134TH 14818 PACIFIC HGWY S 4475 S 134TH PLACE 14004 PACIFIC HGWY S 4522 S 133RD 4455 S 134TH ST 4491 S 134TH PLACE S 133RD AND S 134TH STS 14002 PACIFIC HGWY S 4439 S 134TH PLACE 14025 INTERURBAN AVE S 4550 S. 134TH ST TUKWILA 98188 7216 TUKWILA 98188 241-1519 5411 SEATTLE 19168 244-2146 3599 TUKWILA 98188 5014 TUKWILA 19168 246-4883 5032 TUKWILA 98188 433-0771 7221 TUKWILA 19168 433-6260 4512 TUKWILA 19168 5072 TUKWILA 98188 5014 TUKWILA 98188 5722 TUKWILA 98188 244-4200 5511 TUKWILA 98188 5945 TUKWILA 98188 5912 TUKWILA 19168 5149 TUKWILA 98188 5013 TUKWILA 19168 439-7588 TUKWILA 98188 2434 TUKWILA 98188 5541 TUKWILA 98188 1761 TUKWILA 19168 248-7900 1711 TUKWILA 19168 4841 SEATTLE 98188 244-8450 5812 TUKWILA 19168 431-3575 5087 TUKWILA 98188 7389 TUKWILA 98188 242-3684 5112 TUKWILA 19168 241-1010 5063 TUKWILA 98188 7538 TUKWILA 19168 244-8844 2851 TUKWILA 98188 7218 SEATTLE 19168 433-5690 4731 TUKWILA 19168 None TUKWILA 98188 5541 TUKWILA 19168 243-9800 5211 TUKWILA 98188 246-8545 5812 TUKWILA 98168 244-7232 7699 Drycleaners Grocery store Machine shops, jobbing, and repair Tires—used Brick, stone, related materials, whsl. Photographic studio Air transportation services Locks and related materials Tires—new Household appliances Motor vehicle dealers Hobby and craft supplies Drug store Groceries and related products Automotive parts Wood cabinets Automobile service stations Contractor—roofing Heating, air conditioning contractor Cable and other pay TV services Restaurant Beauty parlor equip. and supply Miscellaneous business services Office supplies Electrical appliances and equipment Automotive repair Paint manufacture Industrial laundry Freight transportation services Business Park Automobile service stations Lumber and other building materials Restaurant Professional instrument repair BUS.XLS allalph Page C-3 Table C-2. Businesses operating in Southgate Creek basin, sorted alphabetically by business name (continued). MAP COUNT NO. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 40 63 3 88 93 98 22 6 97 46 60 65 57 17 19 51 95 13 89 2 94 20 85 5 64 11 47 10 42 90 67 1 HOLADAY PARKS INC 2 HYDRAULIC TECH INC 1 IRON DESIGN CENTER 3 JACK IN THE BOX 3 JET INN MOTEL 3 KENTUCKY FRIED CHICKEN 1 MALONE'S LANDSCAPE CONTRACTING 1 MCLEES DISTRIBUTING 2 NORMED 2 OLYMPIC POSTER CO 1 POWER ENGINEERING 2 PREFERRED PRODUCTS 2 QUALITY RENTALS 1 R&SAUTOCARE 1 SEATAC CAR WASH 1 SEATAC MOTORS 3 SEATTLE MAILING BUREAU 1 SEATTLE TRUCK AND TRACTOR 3 SILVER DOLLAR SALOON 1 SOUND OVERHEAD DOOR SUPPLY (SDS) 3 STAR LIGHT MOTEL 1 STAR NURSERY 3 STOP BY CORNER 1 STRUCTURAL INSTRUMENTATION INC1•2 2 TRUE VALUE HARDWARE 1 UNITED MOTORS 1 US BEARINGS & DRIVES 1 WASHINGTON CARS 1 WASHINGTON MECHANICAL CONTR. 3 WHITE HORSE TAVERN 2 WHITTON 4650 S 134TH PLACE 4389 S 133RD 3450 S 148TH ST 13050 INTERURBAN AVE S 3747 S 142ND 3742 S 144TH 13130 44TH S 4585 S 134TH PLACE 4310 S 131ST PLACE 4495 S 134TH PL 4487 S 134TH PLACE 4475 S 134TH 14604 PACIFIC HGWY S 14612 MILITARY RD S 14224 PACIFIC HGWY S 14120 PACIFIC HGWY S ' 4385 S 133RD 14626 MILITARY RD S 14027 INTERURBAN AVE 4451 S 134TH PLACE 13916 42ND S 14857 PACIFIC HWY S 4611 S 134TH PLACE 3716 S 144TH 13911 PACIFIC HGWY S 12620 INTERURBAN S 14607 PACIFIC HGWY S 13800 PACIFIC HGWY S 14935 INTERURBAN AVE S 4485 S 134TH TUKWILA TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA 98188 292-1160 1711 19168 439-1881 8711 98188 622-5980 3466 98188 (619) 571-2561 5812 98188. 431-0085 7011 98188 246-5158 5812 19168 243-9946 0782 19168 242-7129 5531 19168 242-8228 5912 19168 246-7433 2759 19168 242-7025 3053 19168 98188 242-1110 7359 98188 743-9634 7538 98188 433-1772 7542 98188 5511 19168 431-5700 7331 98188 241-0500 5511 98188 241-9526 5813 19168 248-8300 7699 98188 7011 98188 241-2115 0181 98188 941-6867 5411 19168 244-6100 3829 98188 242-0003 5251 98188 5511 19168 241-1171 3714 98188 246-5183 5511 98188 1711 98188 242-2842 5813 19168 Contractor—heating/air-conditioning Industrial engrs. Architectural and ornamental iron Restaurant Hotels and motels Restaurant Lawn and garden services Auto and truck equipment and parts Drug store and proprietary stores Posters Gasket, packing, sealing mfr. Equipment rental General automotive repair Automotive services—car wash Motor vehicle dealers Mail services Motor vehicle dealers Tavern Household repair services, general Hotels and motels Nursery Grocery store Measuring and control devices Hardware store Motor vehicle dealers Motor vehicle parts/accessories Motor vehicle dealers Contractor—mechanical Tavern 1 On Ecology's list of contaminated sites. 2 Issued NPDES stormwater permit. BUS.XLS allalph ' Table C-3. Businesses operating in Southgate Creek basin, sorted by standard industrial classification. MAP COUNT NO.,.. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 1 62 2 40 3 42 4 43 5 44 6 46 7 1 8 60 9 3 10 4 11 47 12 5 13 80 14 59 15 66 16 48 17 7 18 8 19 49 20 81 21 82 22 83 23 84 24 50 25 64 26 9 27 85 28 12 29 51 30 13 31 11 32 10 33 6 34 14 35 15 1 BRENNAN HEATING CO 1 HOLADAY PARKS INC 1 WASHINGTON MECHANICAL CONTR. 1 BR ROOFING 1 BOW LAKE CABINET SHOP 2 OLYMPIC POSTER CO 1 FARWEST PAINT MFG CO2 1 POWER ENGINEERING 1 IRON DESIGN CENTER 1 A&E MACHINE2 1 US BEARINGS & DRIVES 1 STRUCTURAL INSTRUMENTATION INC1•2 3 ALASKA AIR FORWARDING 2 FLITE TIME 2 CABLE PLUS 1 BIG WHEEL AUTO PARTS 1 A-1 USED TIRES 1 AMERICAN TIRE WHOLESALERS 2 ELECTRICAL INSULATION SUPPLIERS INC 3 AMERICAN LOCK & SUPPLY 3 CLASSIC BEAUTY SUPPLY 3 DOUGLAS PRINTING & OFFICE SUPPLY 3 BETTER BEER 2 GENERAL BUILDING SUPPLY INC 2 TRUE VALUE HARDWARE 1 7 -ELEVEN STORE 2307-22866 3 STOP BY CORNER 1 AUTOS UNLIMITED 1 SEATAC MOTORS 1 SEATTLE TRUCK AND TRACTOR 1 UNITED MOTORS 1 WASHINGTON CARS 1 MCLEES DISTRIBUTING 1 BP GAS 1 GASAHOL 4601 S 134TH PLACE 4650 S 134TH PLACE 13800 PACIFIC HGWY S 13750 PACIFIC HGWY S 3456 S 148TH 4495 S 134TH PL 4522 S 133RD 4487 S 134TH PLACE 3450 S 148TH ST 471ZS 134th 12620 INTERURBAN S 4611 S 134TH PLACE 4443 S 134th PLACE 4491 S 134TH PLACE 4477 S 134TH • 14013 PACIFIC HGWY S 14004 PACIFIC HGWY S 4435 S 134TH PLACE 4475 S 134TH PLACE 4304 S 131st PLACE 4453 S 134TH PLACE 14818 PACIFIC HGWY S S 134TH PLACE 4439 S 134TH PLACE 3716 S 144TH 14207 PACIFIC HWY S 14857 PACIFIC HWY S 14661 PACIFIC HGWY S 14120 PACIFIC HGWY S 14626 MILITARY RD S 13911 PACIFIC HGWY S 14607 PACIFIC HGWY S 4585 S 134TH PLACE 14415 PACIFC HGWY S 14002 PACIFIC HGWY S TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA SEATTLE TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA TUKWILA 19168 248-7900 1711 98188 292-1160 1711 98188 1711 98188 1761 98188 2434 19168 246-7433 2759 19168 244-8844 2851 19168 242-7025 3053 98188 622-5980 3466 19168 244-2146 3599 19168 241-1171 3714 19168 244-6100 3829 19168 433-6260 4512 19168 433-5690 4731 19168 4841 98188 5013 98188 5014 98188 5014 19168 241-1010 5063 19168 5072 19168 431-3575 5087 98188 242-3684 5112 19168 5149 19168 243-9800 5211 98188 242-0003 5251 98188 241-1519 5411 98188 941-6867 5411 98188 244-4200 5511 98188 5511 98188 241-0500 5511 98188 5511 98188 246-5183 5511 19168 242-7129 5531 98188 5541 98188 5541 Heating, air conditioning contractor Contractor—heating/air-conditioning Contractor—mechanical Contractor—roofing Wood cabinets Posters Paint manufacture Gasket, packing, sealing mfr. Architectural and ornamental iron Machine shops, jobbing, and repair Motor vehicle parts/accessories Measuring and control devices Air transportation services Freight transportation services Cable and other pay TV services Automotive parts Tires—used Tires—new Electrical appliances and equipment Locks and related materials Beauty parlor equip. and supply Office supplies Groceries and related products Lumber and other building materials Hardware store Grocery store Grocery store Motor vehicle dealers Motor vehicle dealers Motor vehicle dealers Motor vehicle dealers Motorvehicle dealers Auto and truck equipment and parts Automobile service stations Automobile service stations BUS.XLS sic Page C-5 Table C-3. Businesses operating in Southgate Creek basin, sorted by standard industrial classification (continued). MAP COUNT NO. RANK BUSINESS NAME ADDRESS CITY ZIP PHONE SIC TYPE OF BUSINESS 36 53 37 86 38 87 39 88 40 98 41 89 42 90 43 91 44 97 45 92 46 93 47 94 48 55 49 16 50 56 51 95 52 57 53 96 54 18 55 17 56 19 57 23 58 2 59 63 60 20 61 22 62 21 63 30 64 61 65 65 66 67 2 APPLIANCE DISTRIBUTORS 3 CHINA PAVILION 3 GOLDEN NUGGETT RESTAURANT INC. 3 JACK IN THE BOX 3 KENTUCKY FRIED CHICKEN 3 SILVER DOLLAR SALOON 3 WHITE HORSE TAVERN 3 BARTELL DRUG COMPANY #43 2 NORMED 3 B & B CERAMICS 3 JET INN MOTEL 3 STAR LIGHT MOTEL 2 1 HR CLEANER 1 FLAGSHIP CLEANING SERVICE INC 2 ACHIEVA PHOTO VR INC 3 SEATTLE MAILING BUREAU 2 QUALITY RENTALS 3 CONSUMER PROGRAMS INC 1 ENGINE OVERHAUL 1 R & S AUTO CARE 1 SEATAC CAR WASH 1 HEALTHCO INTERNATIONAL 1 SOUND OVERHEAD DOOR SUPPLY (SDS) 2 HYDRAULIC TECH INC 1 STAR NURSERY 1 MALONE'S LANDSCAPE CONTRACTING 1 ACE CONSTRUCTION & LANDSCAPING 1 FOSTORIA PARK INDUSTRIAL CENTER' 2 BIOMARINE TECHNOLOGIES INC. 2 PREFERRED PRODUCTS 2 WHITTON 14639 PACIFIC HGWY S 14855 PACIFIC HWY S 14025 INTERURBAN AVE S 13050 INTERURBAN AVE S 3742 S 144TH 14027 INTERURBAN AVE 14935 INTERURBAN AVE S 14277 PACIFIC HWY S 4310 S 131ST PLACE 3747 S 142ND , MILITARY RD 4455 S 134TH ST 14216 MILITARY RD S 4385 S 133RD 14604 PACIFIC HGWY S 4455 S 134TH 14004 PACIFIC HGWY S 14612 MILITARY RD S 14224 PACIFIC HGWY S 4550 S. 134TH ST 4451 S 134TH PLACE 4389 S 133RD 13916 42ND S 13130 44TH S 4446 S 131st PLACE S 133RD AND S 134TH STS 4459 S 134TH PLACE 4475 S 134TH 4485 S 134TH TUKWILA 98188 5722 SEATTLE 98188 244-8450 5812 TUKWILA 98188 246-8545 5812 TUKWILA 98188 (619) 571-2561 5812 TUKWILA 98188 246-5158 5812 TUKWILA 98188. 241-9526 5813 TUKWILA 98188 242-2842 5813 TUKWILA 98188 5912 TUKWILA 19168 242-8228 5912 TUKWILA 98188 5945 SEATTLE 98188 431-0085 7011 TUKWILA 98188 7011 TUKWILA 98188 7216 TUKWILA 98188 7218 TUKWILA 98188 433-0771 7221 TUKWILA 19168 431-5700 7331 TUKWILA 98188 242-1110 7359 TUKWILA 98188 7389 TUKWILA 98188 7538 SEATTLE 98188 743-9634 7538 TUKWILA 98188 433-1772 7542 TUKWILA 98168 244-7232 7699 SEATTLE 19168 248-8300 7699 TUKWILA 19168 439-1881 8711 TUKWILA 98188 241-2115 0181 TUKWILA 19168 243-9946 0782 TUKWILA 19168 246-4883 5032 TUKWILA 19168 None TUKWILA 19168 439-7588 TUKWILA 19168. TUKWILA 19168 Household appliances Restaurant Restaurant Restaurant Restaurant Tavem Tavem Drug store Drug store and proprietary stores Hobby and craft supplies Hotels and motels Hotels and motels Drycleaners Industrial laundry Photographic studio Mail services Equipment rental Miscellaneous business services Automotive repair General automotive repair Automotive services—car wash Professional instrument repair Household repair services, general Industrial engrs. Nursery Lawn and garden services Brick, stone, related materials, whsl. Business Park ' On Ecology's list of contaminated sites. 2 Issued NPDES stormwater permit. BUS.XLS sic Page C-6 APPENDIX D Available Stormwater Publications AVAILABLE PUBLICATIONS ON WATER QUALITY/BEST MANAGEMENT PRACTICES U.S. Environmental Protection Agency Manuals (available from EPA 513/569-7562), Guides to pollution prevention: paint manufacturing industry. EPA 625/7-90/005. Guides to pollution prevention: The pesticide formulating industry. EPA 625/7-90/004. Guides to pollution prevention: The commercial printing industry. EPA 625/7-90/008. Guides to pollution prevention: The fabricated metal industry. EPA 625/7-90/006. Guides to pollution prevention for selected hospital waste streams. EPA 625/7-90/009. Guides to pollution prevention: Research and educational institutions. EPA 625/7-90/010. Guides to pollution prevention: The printed circuit board manufacturing industry. EPA 625/7- 90/007. Guides to pollution prevention: The pharmaceutical industry. EPA 625/7-91/017. Guides to pollution prevention: The photoprocessing industry. EPA 625/7-91/012. Guides to pollution prevention:. The fiberglass reinforced and composite plastic industry. EPA 625/7-91/014. Guides to pollution prevention: The automotive refuiishing industry. EPA 625/7-91/016. Guides to pollution prevention: The marine repair industry. EPA 625/7-91/015. U.S. EPA pollution prevention information clearinghouse (PPIC): Electronic information exchange system (EIES)--User guide, Version 1.1. EPA 600/9-89/086. Reports on Waste Minimization Waste minimization audit report: Case studies of corrosive and heavy metal was minimization audit at a specialty steel manufacturing complex. Executive Summary. NTIS No. PB88-107180. Waste minimization audit report: Case studies of minimization of solvent waste for parts cleaning and from electronic capacitor manufacturing operation. Executive Summary. NTIS No. PB87-227013. Waste minimization audit report. Case studies of minimization of cyanide wastes from electroplating operations. Executive Summary. NTIS No. PB87-229662. D-1 Waste minimization --Issues and options. Vols. I -III. U.S. Environmental Protection Agency. 1986. EPA 530/SW-86-041 through -043. Washington, D.C. Washington Department of Ecology. About Aquatic Plants (16 p.). #89-27. Capitol funding program: 1992 report to the legislature *(101 p.). #93-04. Water quality guide: Recommended pollution control practices for homeowners and small farm operators, June 1991 (31 p.). #87-30. Water quality in Washington: A summary of the 1988 statewide water quality assessment. October 1988 ( 1 1 P•). #88-20. Water quality in Washington: A summary of the 1992 statewide water quality assessment. July 1992. (12 p.). #92-62. Water quality laws and regulations. July 1991. (1,200 p.). #89-40. Water quality program inspection manual. June 1992. (210 p.). #92-76. ($21.56) Design criteria for gravity oil/water separators. January 1982. (51 p.). #82-01. Design of monitoring programs for determination of ecological change resulting from nonpoint water pollution in Washington state. March 1986. (287 p.). #91-76. Milfoil--color identification flyer. #91-14. Nonpoint source pollution assessment and management program. October 1989 (383 p.). #88- 17. Protecting groundwater: a strategy for managing agricultural pesticides and nutrients. April 1992. (137 p.). #91-42. Summary of states' water quality permit programs. August 1992. (82 p.). #92-98. Urban Bay Toxics Control Program: Action team accomplishments. September 1987. (43 p.). #87-25. Wastewater discharge permit action plan: Report to the House Environmental Affairs Committee. September 1991. (25 p.). #91-51. Water quality alternative strategies: Pollution prevention through non-traditional approaches. June 1993. (98 p.). #93-24. D-2 Brochures Before you build: Do you have adequate water? Caring for our water is everybody's business --tips to help you protect water at home. #90 -BR - 13. City streams: guidelines for survival (brochure). Commercial waste reduction and recycling manual. January 1992. (44 p.) #90-36. Environmentally sound paper and paper products sold in Washington State. #91 -BR -09. Fact sheet #1: Waste reduction and recycling. June 1990. (4 p.). Fact sheet #2: Autobody shops. June 1990. (4 p.). Fact sheet #3: Automotive repair shops. June 1990. (4 p.) Fact sheet #4: Considerations in selecting a still for on-site recycling. Fact sheet #5: Drycleaners. June 1990. (4 p.). Fact sheet#6: Photoprocessors. June 1990. (4 p.). Fact sheet #7: Printing shops. Generator check list. Focus: counting exemption for recycled used antifreeze. Focus: used shop towels. Focus: waste tires. For hazardous waste...There's no place like home (How to reduce, recycle, and safely dispose of household hazardous wastes). (1 page flyer). Guide to lead -acid batteries. #90 -BR -06. Guide to the used oil problem --What can you do?. #90 -BR -10. Guide to recycling around the house. #90 -BR -10. Hazardous waste do's and,don'ts: Dry cleaning. #91-12C. Hazardous waste do's and don'ts: Electroplating. #91-12G. Hazardous waste do's and don'ts: Pesticide application. #91-12D. Hazardous waste do's and don'ts: Photo finishing. #91-12E. Hazardous waste do's and don'ts: Printing and graphics arts. #91-12F. Hazardous waste --more common than you think. Hazardous waste regulatory alert: CFC's. Hazardous waste regulatory alert: update on used oil filters. Hazardous waste services directory. #91-12S. Home composting --go recycle. How to make waste reduction and recycling happen in your school. (37 p.) #91-38. Is water quality going down the drain in your garage? How service station operators can help prevent groundwater contamination. #91 -BR -08. Managing hazardous waste: auto body shops. #92 -BR -16. Managing hazardous waste: auto dealers. #92 -BR -14. Managing hazardous waste: automotive machine shops. #92 -BR -11. Managing hazardous waste: automotive repair. #92 -BR -12. Managing hazardous waste: radiator shops. #92 -BR -09. Managing hazardous waste: service stations. #92 -BR -13. Managing hazardous waste: tire dealers. #92 -BR -15. Managing hazardous waste: transmission shops. #92 -BR -10. Milfoil (an aggressive water weed). #90 -BR -02. D-3 Pollution prevention planning --Guidance manual for Chapter 173-307 WAC. January 1992. (108 p.) #91-02. Pollution solutions --Special new bulletin for boaters. (2 p. flyer). Recommended practices for the storage of vehicle batteries. Reducing waste in your business --A factsheet. (4 p.). Solid waste reduction and recycling --A handbook of strategies employed by businesses in Washington State. June 1988. (51 p.). #90-48. Stop spreading milfoil around --Long Lake. Success through waste reduction: Proven techniques from Washington businesses. (21 p.). #90- 22. Success through waste reduction: Proven techniques from Washington businesses -Volume 2. (18 p.). #92-45. Success through waste reduction: Proven techniques from Washington businesses -Volume 3. (16 p.). #93-14. Talk'n Trash --Environmental education opportunities for schools through waste reduction, recycling, and litter control. (6 p.). 91 -BR -13. Toxics reduction technical assistance plan. July 1992. (89 p.). #92-35. Turning the tide on toxics in the home --A guide to safer alternatives and proper disposal of hazardous household products. (52 p.). #90-25. Underground storage tanks: What do you have to do? Waste reduction for vehicle maintenance shops. July 1992. (27 p.) Waste reduction in your business. February 1991. (33 p.). #89-56. Waste reduction, recycling, and litter control program. #91 -BR -03. Water quality financial assistance program. #89 -BR -05. What can I do? A home guide to a cleaner, safer Puget Sound. (4 p.). What is a riparian zone? #92 -BR -03. Yard waste composting manual. August 1990. (255 p.). #90-32. King County Surface Water Management Division )3ooklets Native plant guide. October 1993. Streamside savvy. July 1993. Brochures Lakes. November 1993. Get your feet wet (volunteer opportunities). July 1993. Flood warning (no charge) Cedar River basin Green River basin White River basin Snoqualmie River basin Streams. July 1992. Watersheds. July 1992. Wetlands. April 1992. D-4 Watching your waste. PROG 10.13. Business waste line. PROG 10.14. Drains --When you don't know where they go. PROG 10.15. ' D-5 Permitted laundries in King County. PROG 10.16. Small Quantity Generators Are you pouring water quality down the drain? SQG 20.01. Business and Metro. SQG 20.02. Code reference chart (Shields Company). SQG 20.03. Environmental services directory for Washington state. SQG 20.04. Labor and Industries --understanding the right to know. SQG 20.20. Licensed underground storage tanks: Northwest Environmental Compliance Report quick reference guide. SQG 20.21. Metro materials.. SQG 20.22. The sewer is a big dark hole. SQG 20.24. Your business can profit by producing less! SQG 20.25. How on earth can your business produce less and still be more profitable? SQG 20.26. Waste management guidelines for analytical laboratories. SQG 30.01. Controlling brake dust to protect your health. What every auto mechanic should know (EPA). SQG 40.01. Fact sheet: clean cars and clean streams. SQG 40.02. TIM 90.1 --regulation of used antifreeze. SQG 40.40. Choosing a vendor. SQG 40.23. Used antifreeze: Why should automotive shops recycle it? SQG 40.24. Plastic bumper covers. SQG 40.25. Small boat yards and boat repair shops --pollution prevention pays. SQG 50.01. Dental material recyclers. SQG 60.01. Dental office waste management check list. SQG 60.02. Dental office waste stream characterization study. SQG 60.03. Dental office waste stream characterization study --executive summary. SQG 60.04. Dry cleaners: you -do produce hazardous waste, pollution pays. SQG 70.01. Household Hazardous Waste 1. General brochures Citizen's fact sheet. HHW 10.01. Hazardous products equal hazardous waste. HHW 10.02. Paint: waste reduction, recycling, and disposal information. (Urban Wildlife Coalition). HHW 10.03. Safe alternatives to common household products (poster). HHW 10.04. Six steps to a healthy pesticide -free ga.-den (Seattle Tilth Society). HHW 10.05. Ten most wanted pests. HHW 10.06. Trouble-free plants. HHW 10.07. D-6 Small business consultation team. (American Production Service, Seattle, WA) VID 10.01. Municipality of Metropolitan Seattle (Metro) Storm drain stenciling: hints and how -to-dos. (4 p.). Erosion control pays. 1984. (brochure). Are you pouring water quality down the drain? 1989. (brochure). Oil/water separator facts --Protect Puget Sound by keeping oil out of water. 1989. (2 p.). ' D-7 Metro school information program --water quality. 1986. (1 p.). City of Bellevue Stream team guidebook. 1988. (57 p.). Business Partners for clean water --Guidebooks: Water quality protection for construction businesses. Water quality protection for automotive businesses. Water quality protection for landscaping businesses. Water quality protection for food businesses. Water quality protection for maintenance businesses. Miscellaneous Waste disposal and erosion/sediment control methods. The Associated General Contractors of Washington, 1988. (40 p.). Guidebook --Water quality swales. National Association of Industrial and Office Parks. 1991. (25 P.). A citizen's guide to clean water. Izaak Walton League of America, 1990. Citizen's handbook on water quality standards. Natural Resources Defense Council. 1987. Controlling nonpoint-source water pollution --A citizen's handbook. Conservation Foundation/National Audubon Society, 1988. Save our streams kit. Izaak Walton League of America. Wetlands watch kit. Izaak Walton League of America. D-8 APPENDIX E Potential Detention Pond Sites in Southgate Creek Basin O �° ; >i 2� h X 4.3 - 0.9-10G. L//. 00 k N l no at—nA 411.21 0 190 N. LN. OP .5 1 KC SP I• 4110 Yom__. 3O' RL .�� 3. 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