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HomeMy WebLinkAboutSEPA EPIC-199-82 - CITY OF TUKWILA / PUBLIC WORKS - 1982 COMPREHENSIVE SEWER PLANCOMPREHENSIVE SEWER PLAN EPIC- 199 -82 City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 7 February 1983 State of Washington Department of Ecology Olympia, WA. 98504 ATTN: SEPA Register SUBJECT: Final Declaration, Comprehensive Water Plan Final Declaration, Comprehensive Sewer Plan In accordance with the provisions of WAC- 197 -10 -340 (7), we enclose one copy each of the Final Declaration of Non - Significance for the City of Tukwila Comprehensive Water and Sewer Plans. We request that these actions be entered into the SEPA Register as provided in the State Environmental Policy Act. Guidelines. We have enclosed for your records a copy of the Proposed DNS which was circulated to agencies with jurisdiction prior to issuance of the final DNS now before you. If additional information is needed, please advise our office at 433 -1849. TUKW 'v PLANNING DEPARTMENT M. Caughey ssociate Planner xc: Planning Director Public Works Director • • CITY OF TUKWILA OFFICE OF COMMUNITY DEVELOPMENT XXXXXXXEDNAK PROPOSED DECLARATION OF NON - SIGNIFICANCE Description of proposal Comprehensive Sewer Plan Proponent 'City of Tukwila Public Works Department Location of Proposal Tukwila Planning Area Lead Agency City of Tukwila File No. EPIC - 199 -82 This proposal has been determined to ( /not have) a significant adverse impact upon the environment. An EIS (jk/is not) required under RCW 43.21C.030(2)(c). This decision was made after review by the lead agency of a completed environmental checklist and other information on file with the lead agency. Responsible Official Position /Title Brad Collins Planning Director Date 27 December 1982 Signature a'La-a COMMENTS: This Declaration of Non - Significance applies only to the legislative act of adopting the Comprehensive Sewer Plan. Separate environmental assessment shall be conducted for any project which implements the Comprehensive Sewer Plan. King County Executive Randy Revelle Department of Planning and Community Development Holly Miller, Director January 26, 1983 Mr.. Brad.Collins Planning. Director.. City of.. Tukwila .. • 6200 Southcenter Blvd. Tukwila, WA 98188 RE: Propose Dear Mr. Collins:. MEM .JAN -2 8.1983 CITY OF RAC/VILA PLANNN s DEPT. kwila Water and Sewer Plans :On:January20,'1983,.this office received copies. of P.roposed.De ,clarationsof Non- Significance for the City of Tukwilass Compre- hensive, .Water and, Sewer Plans. We note that both:.plans :;"propose the extension of .service.to presently unincorporated areas In..= .order, to -extend such. service ,. King County . Chapter •=13 : :24 :;requires. that .:the .city .must %have its, comprehensive water, and :sewerplans approved .by ::the. King "County Council...- This approval; requirement should -be,.noted on the checklists. • :In addition.to.'this..legal requirement, we have .a great need.for 'the•_`.type :of .'information the..City' s water and sewer plans would provide :: Tukwila abuts or overlaps with Water Districts25, 75- and 125, the City of Kent,- Val Vue Sewer District and King`:.County Sewer and Drainage District No. 4. In order to properly.'= evaluate the strengths and:weaknesses of these systems we need to".know the details of-Tukwiias water and sewer systems. In summary,'.we are anxious to receive both a water-and sewer compre hensive plan :from the City of Tukwila. We are available'to work with -the City during the development of these plans. It has been our experience that County input during the finalization of sewer and water -plans speeds -up and simplifies the County review and approval:"process. As you:may proceed with the development..of the City's,plans,,.please feel free to call me or Gene Peterson at 344- 5286. . RCC:GP:mt . Si�ce,e I I RALPH C. C• BY Utilities Coordinator Building & Land Development Division 450 King County Administration Building 500 Fourth Avenue Seattle, Washington 95104 12061344-7900 CONSULTING ENGINEERS PHILIP M. BOTCH & ASSOCIATES, INC. 11000 MAIN STREET BELLEVUE, WASHINGTON 98004 January 21, 1983 City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 Attn: Mr. Brad Collins Planning Director Re: Comprehensive Water Plan File No. EPIC - 198 -82 Dear Mr. Collins: We have been asked by Water District No proposed Declaration of Non - Significance Environmental Checklist and Appendixes A, Comprehensive Water Plan also was a part of • TELEPHONE (206) 682 -5300 HEM JAN 2 41983 C, - OF TUKKWILA - PLANNING DEPT. D . 125 to comment on your We have scanned your B, and C. • Figure No. 21, your submittal. Service area boundaries of the .City of Tukwila have historically been controversial. Volatile issues have arisen as a result of intrusions by the City into outlying areas. Several attempts have been made by the City at annexations to the north and west. Water District Nos. 25, 125, and 75 will be affected if these expansions are successful. Discussions are underway even now with Water District No. 125 for boundary adjustments at 53rd Avenue South and South 140th Street, and near Beacon Coal Mine Road, and South 133rd Street. Recently, City plans contemplated an annexation of McMicken Heights. This is adjacent to Water District No. 125 and an impact on both Water District Nos. 125 and 75 can be anticipated. The current plan suggests "taking over" certain areas to the east of 51st Avenue South and South of South 180th Street now served by Water District No. 75. Since Water District No. 75 has major facilities in these areas, it does not appear that they will look kindly on proposals made in this plan. It would appear that some further attempt should be made to integrate the water service area with the Comprehensive Zoning Map for the area. Possibly, an accommodation with the special districts can be made that will be less disruptive of their planning. Lacking this, it would appear that a complete EIS might be more appropriate to resolve these is Frank Pearson, WD # #125 Ray Graeber, WD 4175 Document No. 44.38 (sap var Municipality of Metropolitan Seattle Exchange Bldg. • 821 Second Ave., Seattle, Washington 98104 January 18, 1983 Brad Collins, Planning Director City of Tukwila 6200 Southcenter Boulevard Tukwila, Washington 98188 Proposed Declaration of Non - Significance Comprehensive Sewer Plan, City of Tukwila Dear Mr. Collins: agNil LED /J/4 JAN 201983 C OF Tin(WWLA -^ NING DEPT. Metro staff has reviewed this proposal and anticipates no adverse impacts to its wastewater facilities or the public transit system. Thank you 'for the opportunity to.review and comment. Very truly yours, Rddney . Proctor, Manager Environmental Planning Division RGP:lds +.4-va=4:s:r � >..:.<�'c-•- 3 }:;'��'s..r+'tti:.r .i '3�o'Y>.� �.:i?i�r.r'f� �'9� �` �'` rc- ?S..`�„- �.<-- ����z�'��er3+.s - ��,,.¢�.s�''' WILA • sti City of Tukwila 190E 0 6200 Southcenter Boulevard Tukwila Washington 98188 Gary L VanDusen, Mayor 14 January 1983 NORTON DENNIS ASSOCIATES 6133 6th Ave. So. Seattle, WA 98108 Attn: Pat Butler Subject: Environmental Documents, Tukwila Comprehensive Water /Sewer Plans This morning'we received copies of the materials sent out for agency review as directed in our letter to you of 28 December 1982. We were somewhat surprised to notice that your office changed the date of signature for the responsible official on the final declaration form. As a result, the Declaration which went out to the agencies does not match the original in our file. We have, therefore, noted in our file that the declarations were signed on 27 December 1982, but that the date of issuance of the DNS is 11 January 1983, for purposes of compliance with WAC 197 -10 -340. Please make a similar notation in your files. Also, please send us a copy of your cover letter which accompanied transmittal of the material to the agencies, and a list of the agencies contacted. Thanks for your assistance. TUKWILA, P'(IANNING DERARTMENT Mask Caughey Associate Planner MC /blk xc: Planning Director Senior Engineer CITY OF TUKWILA OFFICE OF COMMUNITY DEVELOPMENT XXXXXXX1DDNAX PROPOSED DECLARATION OF NON- SIGNIFICANCE Description of proposal Comprehensive Sewer Plan Proponent. 'City of Tukwila Public Works Department Location of Proposal Tukwila Planning Area Lead Agency City of Tukwila File No. EPIC - 199 -82 This proposal has been determined to Maginot have) a significant adverse impact upon the environment. An EIS ( /is not) required under RCW 43.21C.030(2)(c). This decision was made after review by the lead agency of a completed environmental checklist and other information on file with the lead agency. Responsible Official Brad Collins Position /Title Planning Director Date January 11, 1983 Signature COMMENTS: This Declaration of Non - Significance applies only to the legislative act of adopting the Comprehensive Sewer Plan.. Separate environmental assessment shall be conducted for any project which implements the Comprehensive Sewer Plan. . 1908 City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 Gary L. VanDusen, Mayor 28 December 1982 Horton Dennis Associates 6133 6th Avenue South Seattle, Washington 98108 Attn: Pat Butler SUBJECT: Proposed DNS, Tukwila Comprehensive Water /Sewer Plans Following extensive review of the Environmental Checklists and supporting material submitted with the draft texts of the Comprehensive Water Plan and the Comprehensive Sewer Plan,'the Planning Director as responsible official for the City has approved circulation of a proposed Declaration of Non - Significance for each according to the procedures outlined in WAC 197 -10- 340(3).. In accordance with the terms of your company's agreement with the City for . consultant services, please distribute the proposed declarations and checklists to the various agencies listed below. Each referral should . be accompanied by a cover letter setting forth the inclusive dates of the fifteen day comment period specified in WAC 197 -10- 340(5), and should instruct the receiving agency to return comments directly to the Tukwila Planning Department, attention Brad Collins. Agency referral for Comprehensive Water Plan: - King County -,Water Districts' 75, 125 - Ci:ti:es.. of Renton and Kent - Seattle Water - Department of Social and Health. Services Washington State . - Department of Ecology- Wash.i.ngton State Agency referral for Comprehensive Sewer Plan: - King County - Cities-. of Renton, Kent and Seattle - Yal Vue. Sewer District - Metro-Wastewater Treatment Division - Department of Ecology4ashi.ngton State - PSCOG, King Subregional Council The preceding referral lists represent our best assessment of those agencies having substantial interest or jurisdiction in the adoption of the subject Page -2- Horton Dennis Associ s. 28 December 1982 • Comprehensive Plans. Please add others to the lists as you think appropriate. We appreciate your assistance; please call me if y u have questions (433 - 1849). TUKWIL ANNING DEPARTMENT M.'k Caughey Associate Planner xc: Planning Director Senior Engineer CITY OF TUKWILA OFFICE OF COMMUNITY DEVELOPMENT FINAL DECLARATION OF NON- SIGNIFICANCE Description of proposal Comprehensive Sewer Plan Proponent City of Tukwila Location of Proposal Lead Agency Tukwila Planning Area City of Tukwila File No. EPIC- 199 -82 This proposal has been determined to (O /not have) a significant adverse impact upon the environment. An EIS (iX /is not) required under RCW 43..21C.030(2)(c). This decision was made after review by the lead agency of a completed environmental checklist and other information on file with the lead agency. Responsible Official Brad Collins Position /Title Planning Director Date 3-01 71 11183 Signature -o-A 6.41L:„, COMMENTS: This Declaration of Non - Significance applies only to the legislative act of adopting the Comprehensive Sewer Plan. Separate environmental assessment shall be conducted for any project which implements the Comp. Plan. CITY OF TUKWILA ENVIRONMENTAL CHECKLIST FORM This questionnaire must be completed and submitted with the application for permit. This questionnaire must be completed by all persons applying for a permit from the City of Tukwila, unless it is determined by the Responsible Official that the permit is exempt or unless the applicant and Responsible Official previously agree an Environmental Impact Statement needs to be completed. A fee of $50.00 must accompany the filling of the Environmental Questionnaire to cover costs of the threshold determination. 1. BACKGROUND 1. Name of Proponent: City of Tukwila - Department of Public Works 2. Address and Phone Number of Proponent: 6200 Southcenter Boulevard, Tukwila, Washington 98188 (206) 433 -1850 3. Date Checklist Submitted: October 29, 1982 4. Agency Requiring Checklist: City of Tukwila 5. Name of Proposal, if applicable: Comprehensive Sewer Plan 6. Nature and Brief Description of the Proposal (including but not limited to its size, general design elements, and other factors that will give an accurate understanding of its scope and nature): .v-- - -- a►, �i See Figure 39 and list of projects included with this checklist for Compre- hensive Recommended Improvements. (See attachment A) 7. Location of Proposal (describe the physical setting of the proposal, as well as the extent of the land area affected by any environmental im- pacts, including any other information needed to give an accurate under- standing of the environmental setting of the proposal): (See Figure 2 attached for project boundaries). The study'includes all pro- perty within the Planning Area as defined by the Tukwila Planning Department which consists of approximately 9.8 square miles. (See attachment A) 8. Estimated Date for Completion of the Proposal: The plan recommends certain improvements within 2 years; others as the demand requires. 9. List of all Permits, Licenses or Government Approvals Required for the Proposal (federal, state and local): - (a) Rezone, conditional use, shoreline permit, etc. YES NO X (b) King County Hydraulics Permit YES NO X (c) Building permit YES NO X • . (d) Puget et Sound Air Pollution Control Permit YES NO X (e) Sewer hook up permit YES NO X (f) Sign permit YES NO X (g) Water hook up permit YES NO X. (h) Storm water system permit YES NO X (1) Curb cut permit YES NO X (j) Electrical permit (State of Washington) YES NO X (k) Plumbing permit (King County) YES NO X (1) Other: Approval of Comprehensive Sewer Plan - D.O.E. 10. Do you have any plans for future additions, expansion, or futher activity related to or connected with this proposal? If yes, explain: The Comprehensive Sewer Plan itself is complete, and will be revised as deemed necessary. However, the size and location of future facilities will be affected by the Plan. 11. Do you know of any plans by others which may affect the property covered by your proposal? If yes, explain: Val Vue Sewer District is presently serving are area inside Tukwila. An area South of the present City Limits of Tukwila between the (See attachment A) 12. Attach any other application form that has been completed regarding the pro- posal; if none has been completed, but is expected to be filed at some future date, describe the nature of such application form: No other application has been filed at this time in conjunction with the Compre- hensive Sewer Plan. However, for facilities constructed as a result of the Plan, SEPA procedures will be followed and the proper permits .applied for. II. ENVIRONMENTAL. IMPACTS - (Explanations of all "yes" and "maybe" answers are required) 1. Earth. Will the proposal result in: (a) Unstable earth conditions or in changes in geologic substructures? (b) Disruptions, displacements, compaction or overcover- ing of the soil? (c) Change in topography or ground surface relief fea- tures? (d) The destruction, covering or modification of any uniouP oPnlnaic or nhvciral foatiiroc' YES MAYBE NO YES MAYBE NO (e) Any increase in wind or water erosion of soils, either on or off the site? x (f) Changes in deposition or erosion of beach sands, or changes in siltation, deposition or erosion which may modify the channel of a river or stream or the bed of the ocean or any bay, inlet or lake? X Explanation: tklogr --j -'\ Atfonsizuppows F vTr co4se .I , to:/ REBJLT iZ P & 490sT¢ucS1A.) U t 1W 7 712 1P kg*rt cot-W- m,64,14 A 12,EGDNINVE1.1VED 1pfpgcvmwrs 2. Air. Will the proposal result in: (a) Air emissions or deterioration of ambient air quality? (b)* The creation of. objectionable odors? (c) Alteration of air movement, moisture or temperature, or any change in climate, either locally or regionally? Explanation: Sdort -1)M ple6optqlow of A%1 amuaA T Fart p r piJD Fuex, 60%us%lou API [L1;Su1.T Frorti V 4 4 - ReuTsv exosigocrInJ 3. Water. Will the proposal result in: (a) Changes in currents, or the course or direction of water movements, in either marine or fresh waters? (b) Changes in absorption rates, drainage patterns, Dr the rate and amount of surface water runoff? (c) Alterations to the course or flow of flood waters? (d) Change in the amount of surface water in any water body? (e) Discharge into surface waters, or in any alteration of surface water quality, including but not limited to temperature, dissolved oxygen or turbidity? (f) Alteration of the direction or rate of flow of ground waters? • (g) Change in the quantity of ground waters, either through direct additions or withdrawals, or through interception of an aquifer by cuts or excavations? X X X x • YES MAYBE NO (h) Deterioration in ground water quality, either through direct injection, or through the seepage of leachate, phosphates, detergents, waterborne virus or bacteria, or other: substances into the ground waters? (1) Reduction in the amount of water otherwise avail- able for public water supplies? Explanation: (d,e,i) The availability of additional sewers will lead to water consumption and may cause an increase in population. e {d) 440egAC. sIsTw aowN n. ease WILL f asmipouAL Walt . coosuµrnoO 047.4410G GiLv.M - dIUM�T►e~s of RMS.( w4T�rt 1 61-I!.1 soOrcces pOb 4. Flora. Will the proposal result in: "'"" 11"2-1uLJ Uo U$. s ar 1"4t11' W"IM- WA,Nt To Ve dre EA) RO V (a) Change in the diversity of species, or numbers 311) ¢tCnra cv e�crsr syst 1.13,1u►Ge mkt*. A.-- of any species of flora (including trees, shrubs, NAT Posinu- ii+r/b.GT ru This grass, crops, microflora and aquatic plants)? x (b) endangered species of flora? (c) Introduction of new species of flora into an area, or in a barrier to the normal replenishment of existing species? Reduction of the numbers of any unique, rare or (d) Reduction in acreage of any agricultural crop? Explanation: paoross,c, sewFL sexvice To Gu'•L I M is A,R.E. Hest aF rksivtzowts To Mott,- INT swe use. 5. Fauna. Will the proposal result in: (a). Changes in the diversity of species, or numbers of any species of fauna (birds, land animals including reptiles, fish and shellfish, benthic organisms, insects or microfauna)? (b) Reduction of the numbers of any unique, rare or endangered species of fauna? (c) Introduction of new species of fauna into an area, or result in a barrier to the migration or movement of fauna? X X X (d) Deterioration to existing fish or wildlife habitat? Explanation: approP Nctola i� 44: RAurn .y odor. couTretsote' Tb H&K).T pa.iota•'loN • X 6. Noise. Will the proposal increase existing noise levels? Explanation: 74'4 brLbRW coo gl-RoC1-101J Noise - Lisvat. I k1ot.Pase, 7. Light and Glare. Will the proposal produce new light or glare? Explanation: 8. Land Use. Will the proposal result in the altera- tion of the present or planned land use of an area? Explanation: The plan will allow for development or redevelopment of properties being served by sewer lying inside Tukwila's jurisdiction to the potential envisioned by Tukwila's Comprehensive Land Use Plan. 9. Natural Resources. Will the proposal result in: (a) Increase in the rate of use of any natural resources? (b) Depletion of any nonrenewable natural resource? Explanation: See Item 3. 10. Risk of Upset. Does the proposal involve a risk of an explosion or the release �f hazardous substances (including, but not limited to, oil, pesticides, chemicals or radi- ation) in the event of an accident or upset conditions? Explanation: YES MAYBE . NO X X i YES MAYBE NO 11. Population. Will the proposal alter the location, distribution, density, or growth rate of the human population of an area? Explanation: Construction of proposed facilities will occur in conjunction with increased population to the area. An increase in popula- tion will result in increased housing, pedestrian and vehicular traffic, and governmental services. 12. Housing. Will the proposal affect existing housing, or create a demand for additional housing? _ Explanation: See Item 11. 13. Transportation /Circulation. Will the proposal result in: (a) Generation of additional vehicular movement? (b). Effects on existing parking facilities, or demand for new parking? (c) Impact upon existing transportation systems? (d) Alterations to present patterns of circulation or movement of people and /or goods? (e) Alterations to waterborne, rail or air traffic? (f) Increase in traffic hazards to motor vehicles, bicyclists or pedestrians? Explanation: See Item 11. X X 14. Public Services. Will the proposal have an effect upon, or result in a need for.new or altered governmental services in any of the following areas: (a) Fire protection? - X (b) Police protection? X (c) Schools? X (d) Parks or other recreational facilities? X (e) Maintenance of public facilities, including roads? • • YES MAYBE NO (f) Other governmental services? Explanation: See Item 11. X 15. Energy. Will the proposal result in: (a) Use of substantial amounts of fuel or energy? X (b) Demand upon existing sources of energy, or require the development of new sources of energy? Explanation: 16. Utilities. Will the proposal result in a need for new systems, or alterations to the following utilities: (a) Power or natural gas? _ (b) Communications systems? _ (c) Water? _ (d) Sewer or septic tanks? X (e) Storm water drainage? _ (f) Solid waste and disposal? _ Explanation: • (c,d,e,f) An increase in wastewater discharge will cause the need for sewer improvements. The increased population (causing the additional discharge) will also cause an increase in water use, storm water drainage, and solid waste. 17. Human Health. Will the proposal result in the crea- tion of any health hazard or potential health hazard (excluding mental health)? X X Explanation: X X • YES MAYBE NO 18. Aesthetics. Will the proposal result in the obstruc- tion of any scenic vista or view open to the public, or will the proposal result in the creation of an aesthetically of -. fensive site open to public view? Explanation: 19. Recreation. Will the proposal result in an impact upon the quality or quantity of exist- ing recreational opportunities? Explanation: 20. Archeological /Histroical. Will the proposal result in an alteration of a signifi- cant archeological or his - torical site, structure, object or building? Explanation: CERTIFICATION BY APPLICANT: I, the undersigned, state that to the best of my knowledge the above information is true and complete. It is understood that the lead agency may withdraw any declaration of non - significance that it might issue in reliance upon this checklist should there be any willful misrepresentation or willful lack of full disclosure on my part. Signature and Title Date X X X ATTACHMENT "A" Checklist Section I--Item 6 The Comprehensive Sewer Plan prepared for the City of Tukwila discusses the existing land use plan, existing and projected population growth within the existing service and planning areas, sewage flow and design criteria, the existing system, and proposed system expansion and improve- ments. Sewer system improvements include collection of wastewater and discharge to METRO or treatment. If actual land use and /or population vary significantly from that used in preparation of the comprehensive plan, it would be necessary to reevaluate the size and lucation of proposed faci- lities. Some improvements would be provided as dictated by the demand for such facilities, while other needed improvements would be funded with funds on land and revenue bonds. In most cases, collection sewers would be financed by the developer. Wastewater treatment is performed at the METRO facility in Renton. Checklist Section I- -Item 7 Most of the attention is focused, however, on the 3.7 square miles presently within the City Limits and which presently is being sewered by Tukwila. This includes 2700 acres of alluvial lowlands lying. west of the Green River, 2800 acres of glacial plateau, and 750 acres of steep wooded hillsides connecting the lowlands to the plateau area to the west. (See Chapter III of the Comp Plan for expanded description of the planning area). Checklist Section I- --Item 11 Green River and I -5 is shown to be served in this plan by Tukwila if the property so requires. This area can also be served by City of Kent. Relationship to Basin Wide Sewer Plan The existing and proposed sewer system for the City of Tukwila is dependent upon METRO accepting all sewage from the City for treatment and disposal. METRO is presently planning an enlargement to the Renton Treatment Plant and an outfall to Puget Sound to accomodate increased flows. The Comprehensive Sewer Plan will be updated and re- evaluated at least once every five years. ,Tukwila's plan is developed under the premise that METRO will continue its role for regional treatment and disposal for the metropolitan area. Relationship to Adjacent Cities and King County'Plans • With the exception of an area lying south of the present city limits of Tukwila between I -5 and the Duwamish River, this plan is consistent with the plans and service areas of the City of Kent and City of Renton. The service boundary on Tukwila's east side coincides with these municipalities. The ,Comprehensive Sewer Plan is consistent with Val Vue Sewer District which borders on the west side and presently no sewers exist in the areas north of Tukwila in Allentown. The Comprehensive Plan has been developed in compliance with the Tukwila Zoning and land use projections for the Service I Area . • • Service Area Agreements ,Two areas of existing or future overlap exist. The first is an area of McMicken Heights lying inside the City and presently being served by Val Vue Sewer District. Agreements presently exist as discussed in detail within the Comprehensive Sewer Plan and they are adequate to govern service in this area. If substantial areas of McMicken Heights continue to annex to Tukwila, these agreements-will be re- evaluated at such time regarding the possibility of taking over the sewers lying inside areas newly annexing to the City. The second area of..potential conflict is the South Service Area which is in the Tukwila Planning Area, presently in King County, and can feasibly be served by the Tukwila Sewer System with appropriate future system improvements. This area is also shown by the City of Kent as a possible , (future area they can serve. A portion of this area has already requested 'sewer service from Tukwila. • APPENDIX A • CITY OF TUKWILA COMPREHENSIVE SEWER PLAN' SUMMARY AND DISCUSSION OF ASSUMPTIONS PROJECT RECOMMENDATIONS Purpose This summary is included to provide a concise synopsis of the key information presented in the City of Tukwila's Sewer Comprehensive Plan. It is intended to be presented in a non - technical manner. Recommendations are summarized and pre- sented in list form. (For further detail a copy of the complete Plan is on file at City of Tukwila, Public Works Department). Assumption's I) Study Area The study includes all property within the Planning Area as defined by the Tukwila Planning Department which consists of approximately 9.8 square miles.1 Most of the attention is focused, however, on the 3.7 square` miles presently within the City Limits and which presently is being sewered by Tukwila. A discussion and identification of the physical features, including geology, soil characteristics, surface water, ground water, lakes and ponds and existing development, is included in Chapter III of the Plan. II) Growth Projections The three scenarios described below establish the bass conditions for assessing the adequacy of the existing sewer system given the most likely ways in which the city may develop through 1990. Resident and employee population levels are pro- jected for each scenario, as are land use statistics for both residential and non- residential activity. These data may be found in detail in Chapter III of the text, 1 • Scenario 1 - Existing Conditions. This is based on 1980 housing and employment figures. This scenario is to establish development conditions and population. Scenario 2 - Vacant Land Build -Out This scenario is developed according to the 1982 zoning ordinance by filling the vacant land to a total build - out condition. Scenario 3 - Redevelopment Build -Out This scenario assumes that portions of the planning area ,will redevelop . to high intensity land uses and all vacant • land will develop and infill to a higher intensity use. It should -be.noted that . the intent `of the Comprehensive Sewer-Plan ` under-each of the scenarios described above'is to react to growth pressures.withi'n: thecommuni;t and not necessari ly to' encou "rage or :direct ' growth.. III) Design Criteria Design Criteria, established in the Plan, is based on "Criteria for Sewage Works Design" by the State of Washington Department of Ecology. Criteria has been established to govern all future improvements to the system and provide for uniformity in design when sizing pipes and pump stations. It also will ensure a system that can be economically maintained by the City maintenance staff. 'TV, TIME4RAME No attempt has been made to make any projection for specific improvements beyond the next five year period by which time all presently needed improvements would be under construction or completed. The need for further construction of sewer mains will be dependent on the actual growth and redevelopment rate except for those improvements that are requested by the developers. 2 System Analysis and Proposed Improvements I) Existing Conditions IThe existing Tukwila sewer system consists of approximately 140,000 lineal feet of 6 -inch thru 24 -inch diameter sewer pipes, approximately 470 manholes and height (8) pump stations. This system collects the sewage generated by the !residences and buildings within the service area and transports it to METRO (Municipality of Metropolitan Seattle) pipelines. From these lines the sewage flows to the METRO- Renton treatment plant, where it is treated and discharged to the Duwamish River. METRO is presently in the development phase to increase the size of the Renton treatment plant and construct an outfall that would dis- charge the effluent directly to Puget Sound. A number of problems in the existing Tukwila sewer system have been identified including: heavy grease deposits in many of the pipes; some pipes have settled due to poor soils and have developed sags; some leak into and outof the system have been identified; a few sewer lines are undersized for present or anticipated sewage flows; several pump stations should be eliminated while one needs to be !enlarged or replaced. Other system improvements are needed as detailed in the ;Plan. In addition, pump stations have the potential and capability to overflow when a power outage occurs. Presently the City has no standby power units for any of their stations. The existing sewer system was analyzed to evaluate the capacity of all existing sewer interceptors, laterals and pump stations with regard to both current domestic sewage flows and projected ultimate domestic sewage flows which may result from future growth. Where individual components of the system were inadequate, recommend- ations were made for reconstruction, elimination, diversion, zoning restrictions, jinfiltration /inflow rehabilitation, and /or more intensive studies. The recommenda- 3 • • tions were based on a cost effective analysis of all defined alternatives. A needed capital improvement list which ranks the project in relative order of priority is lattached. !Areas which are not presently sewered (both existing franchises and possible annexa- tions within the scope of the study) were analyzed to ascertain the most viable 'alternative for providing sewer service, and to determine the impact of serving these areas on downstream components. II. Summary of System Improvements A detailed engineering study was completed on a drainage basin -by -basin basis. Where data was available, a study was conducted to evaluate whether undesirable inflow from ground or surface water was robbing the existing pipes of needed capacity. This study is referred to as in Infiltration /Inflow Study. All ipas.t studies and television reports on internal inspection of the system were reviewed and included in system recommendations. '.Needed improvements, which are downstream from other deficient parts of the system -and which must be completed prior to upstream modifications, are noted as such in the Comp Plan. Notation is also-made of those modifications which are of the most imminent nature. This provides an administrative tool to determine which ;individual projects should take priority.; The basin -by -basin study evaluated all defined alternatives where problems were discovered. A cost analysis, including associated maintenance costs, is ,included. Where preferred alternatives, either based on cost considerations, engineering reasons or maintenance reasons were defined, recommendations were made. In several basins, alternative recommendations were not specific. Where two solutions were relatively equal, both were included in the recommended improvement plan. All needed capital improvements are summarized in the Plan and shown on Figure 39 attached. 'Infiltration /Inflow Analysis' The purpose of the Infiltration /Inflow Study (I & I) is to review existing information and assess, where possible, if excess infiltration /inflow exists in specific sub - basins of the Tukwila Sewer System. Since observed I & I rates are well below the 1,100 gal /per 'acre design value, it is concluded that I & I is not presently a serious problem for -any of the pump station tributary areas studied. • ,Sewage Pumping Considerations The City's eight (8) existing pump stations were analyzed not only for adequate capacity, but also for the possibility of elimination. The installation of sewage pump stations in the study area often provide the cheapest initial cost solution for providing sanitary sewer service, to an area. In light of the increasing concern for minimizing energy consumption, a greater awareness of the potential for sewage overflows and the escalating operation and maintenance costs of the installations, a higher priority is being placed on eliminating sewage pump stations wherever possible. Operation and Maintenance By far, the most serious problems. in the Tukwila Sewer System are caused by 'grease deposits in side sewers, collector sewers, manholes, wet wells and force mains. .Grease problems rob the Sewer. Department of valuable time (including'overtime charges) and equipment better spent on their ongoing system- 'wide preventative maintenance program. In addition, excessive grease entering the METRO trunk sewers violates METRO's sewer use ordinance and makes Tukwila vulner- able to legal action. The Comp Plan recommend, :.he elimination of four (4) pur;..stations and the addition of many grease traps. Over 20,000 lineal feet of new sewer lines and force mains would also be added. Assuming these changes are made, no additional maintenance personnel should be required as the system expands due to the reduction in time consuming pump station maintenance and grease problems. III. Implementation Various funding alternatives to cover the needed improvement costs are discussed in detail in Chapter VII. Some of the needed sewer system improvements are eli- gible for a Washington State DOE Referendum 39 Construction Grant covering 50 percent of the eligible construction costs. It is recommended that a General Facilities Charge be imposed on all new buildings for development and property . that redevelops. This charge is in lieu of the present regular connection charge and trunk sewer charge and would fund a portion of the neede improvements. A re- duction in monthly rates is included in this plan as outlined in the recommendations that follow. Additional funding for the needed improvements includes utilizing a portion of the $1,000,000 + presently available in the sewer fund. Ordinance changes are recommended to adopt more detailed requirements in establish- ing oil /grease separation, standards for private pump stations and other developer . extension policies and requirements. IV. Recommendations As a result of this study, the following recommendations and conclusions are made as part of the City of Tukwila's Comprehensive Sewer Plan: 1. It is recommended that the City adopt the Comprehensive Plan and Figure 39 attached as the plan which guides system improvements and new development 2. It is recommended that Tukwila reduce City wide sewer rates and institute a General Facilities Charge for Needed Capital Improvements as detailed below. This facility charge would replace the present "regular connection charge" and ".trunk sewer charge ". Recommended Rate Reduction $1.00 per month per residential equivalent and $.50 per 100 cubic feet. Recommended Gen•l Facility Charge Initially U/gross square foot floor area + 1t increase per year. Residence - $120 /residence + $12 /year increase. Multi -unit - $80 /unit + $10 /year increase. 3. It is recommended that Tukwila proceed with engineering design, studies and construction for Needed Capital Improvements, based on relative priority. Funding should be from existing cash on hand, grants and the General Facility Charge. Estimated Cost of Needed Improvements - $1,420,000 (Sewer Department portion) 4. It is recommended that Tukwila apply for D.O.E. Grant Funding for qualifying Needed Capital Improvements, and that the City closely monitor Referendum 39 funds and relative grant eligibility requirements. 5. It is recommended that Tukwila Public Works Department review all development plans before permitting buildings greater than 100,000 SF or heavy industrial uses generating more than 0.5 gallons /SF /day of sewage or process water. This review should insure compliance of such new developments with the spirit intent and design principles of the Comprehensive Sewer Plan. 6. It is recommended that Tukwila develop a City wide operation and maintenance manual (0 & M Manual) and a developer extension manual as outlined in the Plan. 7. It is recommended that Tukwila adopt ordinances governing grease traps, and private pump stations and update ordinances governing new sewer extensions and services, as outlined in the Plan. 8. It is recommended that Tukwila - extend sewer service to an area lying between I -5 and the Duwamish River and just south of the City Limits (South Service Area) if requests and applications by property owners are received. This area can be served at a reasonable cost to the property owners as discussed in the Plan. 7 9. With the constructs of the Needed Capital Improvelts, man -hours required for maintenance should decrease slightly from present levels. This should help to free existing staff to accomplish necessary routine and preventive maintenance. We do not believe additional maintenance staffing is required to implement this plan. 10. It is recommended that Tukwila proceed with planning, procurement, design and construction of the miscellaneous recommended improvements as outlined in Chapter VI of the Comprehensive Sewer Plan. Project for Cross Referencing Misc. Misc. Misc. Misc. Misc. 3 4 9 TABLE 12 RECOMMENDED NEEDED CAPITAL IMPROVEMENTS Listed in Relative Order of Priority Drainage Chapter Basin VI -52 N/A VI -52 N/A VI -52 N/A VI -52 N/A VI -53 N/A VI -11 2 VI -16 3 'VI -23 8 12 VI -26 11 Project Description Purchase 2 Portable Standby Power Install 6 Plug Adaptors for Portable Power Prepare 0 & M Manual for Entire System & Developer Extension Manual Recommended Pump Station No. 1 Improvements Install Bypass Connections for Pump Stations Eliminate Pump Station No. 4 Reroute Service Lines to Haggards &.Riverside Inn Reconstruct Intruding Tee at Southcenter Mall Eliminate Pump Station No. 3 17. VI -40 13 Perform I/I Work, Reconstruct Sewers, Add Grease Trap, etc. Misc. VI -54 N/A Flush & T.V. Portion of System Not Completed 100,000 1.f. Misc: VI -53 N/A Upgrade Telemetering System, Install Dialers, etc. 20 VI -48 N/A Replace Pump Station No. 2 and Upgrade System Initial Needed Capital Improvements Phaca 20 VI =48 N/A 19 VI -43 ' 13 - 10 VI -25 9 Gravity Sewer and Force Main to South Service Area 1,800' of 10" Sewer on Southcenter Parkway. 500' of 8" & 150' of 15" Casing Along S. 158th Street Under West Valley Highway Primary Funding Cost Source 70,000 Sewer Dept. 1 24,000 Sewer Dept. 1 $ 25,000 Sewer Dept. $ 22,000 Sewer Dept. $ 24,000 Sewer Dept. 1 $ 100,600 Sewer Dept. 1 $ 5,000 Sewer Dept.. $ 3,000 Sewer Dept. $ 115,300 Sewer Dept. 1 $ 68,500 Sewer Dept. $ 105,000 Sewer Dept. $ 30,000 Sewer Dept. $ 848,500 Sewer Dept. 1 $1,419,100 $1,197,500 Developer 1, 2 $ 104,400 Developer 2 $ 45,000 Developer 2 TABLE 12 RECOMMENDED NEEDED CAPITAL IMPROVEMENTS (continued) Project # for Cross Drainage Referencing Chapter Basin Project Description 13 VI -29 10 2,800' of 10" & 1,000' of 8" Sewer to Serve Basin 10 15A & 15B VI -34 13 Segale Business Park Revision Alternative I or III 2 VI -8 1 Eliminate Pump Station No. 5 1 VI -8 1 550' of 8" Sewer to Serve Allentown Addition 18A VI -41 13 Eliminate Pump Station No. 8 5 VI -18 3 3,000' of 8" Sewer on Beacon Coal Mine Road 6 & 6A VI -18 3 650' of 8 ", 300' of 15" Casing to Service Nielsen Dairy Property 7 VI -21 3 Eliminate Pump Station No. 6 16 VI -38 13 1,000' of 8" Sewer Along South 178th Street 11 14 VI -25 VI -31 9 Install Grease Trap 12 Install 2 Grease Traps (1) Grant Funds Possible (2) L.I.D. Possible Cost $ 208,800 $ 38,000 $ 229,700 $ 52,600 $ 25,500 $ 170,500. $ 139,200 $ 73,700 $ 147,200 $ 46,400 $ 7,250 $ 14,500 Primary Funding Source Developer 2 Developer 2 Sewer Dept../ Developer 1 Developer Developer 1,2 Developer 2 Developer 2 Sewer Dept.. 1 Developer Sewer Dept. Sewer Dept. • • THRESHOLD DETERMINATION Comprehensive Sewer Plan (EPIC- 199 -82) Proposed Action The City of Tukwila Public Works Department has prepared an environmental checklist for a program proposal constituting a comprehensive sewer plan. The purpose of the plan is to analyze the existing condition and function of the system and to recommend improvements which will enable it to meet or exceed minimum health and safety protection standards and enable it to keep pace with expected patterns of residential and industrial growth in the community through 1987 and annual updates thereafter. City Council approval of the plan must precede its implementation. Checklist Review The Comprehensive Sewer Plan is a programmatic proposal. The checklist as submitted does not analyze specific project actions and alternatives sug- gested in the plan but attempts to identify the impacts associated with generic classifications of capital improvements. A narrative assessment of alternative project actions is provided for each sub -area in Chapter VI of the plan document. Within each sub -basin where conditions warrant reconstruction of existing lines, renovation or elimination of pump stations or extension of new services, potential impact areas have been identified. The most common topics of concern seem to be in the areas of economic feasibility, growth management and energy conservation. A comprehensive analysis of these topic areas for each alternative would be beyond the test of disclosure for a programmatic action proposal. However, as each individual project is advanced to the construction approval stage, SEPA review either in the form of an E.I.S. or an expanded checklist should study that project's cost impacts, affect on pace and geographic distribution of population and development, and energy consumption. In addition to these common topics of environmental concern, the matrix analysis reveals the following additional concerns unique to the actions/ alternatives of various drainage basins: Basin 1: The plan document concerns itself primarily with future extension of sewer service east of the Duwamish for the Allentown area. Tt also assumes no change in the predominant low- density residential use pattern of the area. No notice is taken in the plan text of the extensive vacancy or under utilization of existing M-1 zoned lands. Future environmental review should address the adequacy of the improved system to accomodate development according to growth management scenario #2 described in Chapter III of the plan. Page -2- THRESHOLD DETERMINATE Comprehensive Sewer n (EPIC- 199 -82) Basin 3: • The text indicates that the Seattle Rendering Works is part of Basin 3, yet the maps 21 and 22 seem to suggest that the rendering plant is actually a part of Basin 2. The contradiction implies that neither area is being planned to accomodate the effluent capacity of the plant and suggests that the sewage improvements in the 27 acre portion of basin three which includes Foster Golf Course (not 50,000 of M -1) may be unnecessary. This concern should be researched in the construction phase and resolved prior to final assessment of its relative priority. Basin 9: Again, the ultimate build -out scenario has been misinterpreted. The City's new zoning map designates the Nelson Place area "light industry." Thus, the projected retail business effluent generation factor may underestimate actual buildout conditions. Basin 10: Basin 10 is projected to develop as a formally platted industrial park. The text does not recognize the possibility of a boundary realignment with all or part to this territory going to the City of Renton, as has been discussed between Tukwila and Renton officials for several years. Neither does the text discuss the alternative of providing sewer service to this area through the City of Renton. The qualitative impacts of these potential service strategies should be investigated before the city enters into a committment to infrastructure extension in this area. Basin 14: This geographic subarea is for the most part outside the City and will require extensive negotiation amoung competing service districts to determine optimum service boundary configurations based on the Tukwila, Kent and King County Comprehensive Land Use Plans. The Comprehensive Sewer Plan contains an ultimate build -out service scenario assuming full service of the area by Tukwila. A less ambitious alternative for upgrading the south area service interceptor and the Segale Business Park area is identified for comparative purposes. Conclusion The matrix analysis suggests several trends which deserve further attention in the implementation stage of the Comprehensive Sewer Plan: A) Initiation of sewer service to presently unserved territory: More intensive environmental impacts are anticipated in a number of topic areas, most notably the elements of the natural environment. Seconary impacts on elements of the human environment are also expected in the areas of population distribution, housing, transportation system capacity and energy :i useage. Staff is persuaded, therefore, that any effort to initiate service in these sub -areas will have a growth inducing effect which must be measured according to existing community develop- ment policy in the context of a formal environmental impact statement. Page -3- THRESHOLD DETERMINATION Sewer n (EPIC- 199 -82) • B) Elimination /consolidation of pump stations: While the impacts on the natural environment from this generic class of capital improvements is generally less intensive than the no- action alternative, each specific case should include, in an expanded checklist format, a quantitave discussion ... of energy and water consumption impacts system -wide and an assessment of economic cost /benefit relative to the timing and complexity of each project. C) Service boundary adjustments: In each instance where sewer service is proposed to extend beyond the City's corporate boundaries or beyond its present sewer utility franchise area, the matrix suggests a causal relationship to growth pressures and a possible modification of land use policy in the affected sub -area. Again, the magnitude of these impacts .i.s.: anticipated to be substantial, and the multitude of juris- dictions involved argues strongly the appropriateness of applying the public disclosure process of the formal impact statement .. when specific projects are actually brought to the permit stage. Recommendation Staff recommends the approval of a Declaration of Non - Significance for the Comprehensive Sewer Plan but with the expressed stipulation that this decision applies only the the legislative act of adopting the plan and that separate environmental assessment shall be required for any of its implementation programs. Proposed Action /Alternative ENVIRONMENTAL ELEMENTS a) L r0 r Q) V) C7 N (I) - L MS CO a) 4--) 4-) Q) S- C V) -C -C) S- S- +-, 0 M •r Q) C +-, rp •r r9 r m O •r rC co W+ Q 3. u u Z J J Z Risk /Hazard C O +� V) •• L ( A a) 4-) an 0 Q) •r tC) C Q. U > 4-) L r •r N •r D) •r +-•) = V) C > Z. r- 0_ O (O S- a) •r ITS d = F— V) W = = Aesthetics Recreation Cn N C O U .0 r r L) a) E c U O E W U Recommended Priority - Indicates impact may be more intensive than that of no- action alternative = Indicates impact may be similar to that of no- action alternative + Indicates impact may be less intensive than that of no- action alternative Sewer Extens. E. of Duwamish - - - - - - + + _ _ _ - + Low Eliminate Pump Station 5 = + + _ _ + _ _ _ + _ _ _ _ + + _ _ = _ + = „ Eliminate Pump Station 4 = + + _ _ + _ _ _ + _ _ _ + + + _ + _ _ + = Moderate /High Upgrade Pump Station 4 + + ' Serve 27 Acre Area - - + - + - - - + Low /Moderate Serve 12.7 Acre C -2 Area - - - - + - - - + Eliminate Pump Station 6 = - + + - - - + _ _ _ + - - _ _ _ + + + - Replace Pump Station 6 Basins 4 through 8 require only minor repairs; no capital improvements forecast O1 Serve 11 AC Area - Nelson P1. + - - - + Moderate Construct Grease Trap + - - - + - - + - - - + - ° Serve Basin 10 - - - + - + - - - - Moderate r, '' Eliminate Pump Station 3 = + + _ _ + _ _ _ + _ _ _ + + + _ + _ _ + = Moderate /High Upgrade Pump Station 3 - - - - - - - + - - - - - + - - - + - Construct Grease Trap Vaults + - - - + - - + - - - + - Low Upgrade Sewers - Segale (Alt 1) - - - - + - - - + + - - - Upgrade Sewers - Segale (Alt 2) - - - - - - - - + + - - - - - Moderate Pvt Sewer Upgrade- Segale' (Alt 3) - - - _ - + - - - - + + - - - - + - Serve W. of S.C. Pkwy - - - - - - Moderate Reconstr./Maintenance + + - - - - + - High Upgrade Pump Station 8 - - - - - + - + - - - - + - - - - - Low Eliminate Pump Station 8 = + + _ _ + _ + = + _ _ _ + + + _ + _ _ + = Upgrade Line Soctr. Blvd. to Minkler _ - - - + - - - - + + + _ _ _ = + = High - ' Serve South Service Area - + - + + - - _ - + Rebuild interceptor to Segale - + - + + = _ _ + + - Indicates impact may be more intensive than that of no- action alternative = Indicates impact may be similar to that of no- action alternative + Indicates impact may be less intensive than that of no- action alternative QENTON . 7.21cLiks,a1. I .--- • V4Mile Aactprovinale Scale Y2 Mile CM.51.P.ELI.P R.R. / ( 4 KENT 4141444.4.4( ttwe„ „. • .--)(/ it / -S'k,53.9 7, ,.--7-7.-4-41`fi:nciover Lpork eas,L L______71-------------„,,I, tram '7 `Twsi. .----y N ....2.,, .-----) —ii-- I r ir---- -111 AndovL el': . ' ' --;---,.--- =-'• i ; r---,. .. / . -------___ .. ,,,<-----",„. ----?:--:.__ -_-_,.._2 • 1 ' - •----<- 11 11 . i__ Par* ..,------1---lt L .m„. elf/ 1 rki —IF n .0 i t: IF_______ . ......____, N--.._■94;z-- -, +72 'i 1 , !i I% g 11 1 -....i i. ■ St' , t -- ..---...,.. -,...___ . "4,7 ..;_ A / i 14 I ti I-Z I VI; L-■._,___.4 //is. I 62ndA Ave. 5. i 1 4: ,. ...; 1: . I .* 11 . , , _k.77,._tA* 1 • *----- /-, ?,/11 C */ ' Jk I" TUKWILA t:!, 1 ,„ i • 1 1 1! e/ce,—_a„, _____ --I:7-- 5 $ D NO. 4 ---.---/.r.cri, - ,, ty ,,, „ 1 . . ti, /58,y, ib.,____,e,___11 S. J .‘.,'• 6,-:' i _sf, i ! I---------=::---1 7-------------2:-------------:„ 11- 11 I II 1 . 41\ ■ 1.--/-' Esi..±7...... LCenier ---1--. ---z.--:„ ----..,..„, -.• J '.-.',(.' ,.• Parkway ___.-------- - ..-• * - -I! • , ir.,- ,-11i56/6 liAW.S. 11 1: N: c • k *2 ,....,-- i r ,, ti ••::• I 1 tu ,..-_,..‹.----- 4.. c_ 55H1 Ave Ili s. ...L --1 1 1 ,i_ _ _ _II 1.-,_e--:-• - 1. 0 ■ • MP Si Ave. S. I -1 t I N • I [4_40,7_1U14 •ve-__,-5! -1 • if; tOze... 1,4J 1 Tukwila Cily LIMI.715 VAL-I/1/E MN/A/TANS TR /5. APEX) 4r5&?darg ' flfl- VAL -VIJE SEWEP DISTPICT CITY OF TUKWILA SEWER SERVICE AREA AND ADJACENT MUNICIPALITIES Oa PROJECT NO. FIGURE 3 ail ........ ............ ...... .. ..... ...... . ;,,; ttttlUUU�t1Gutl��nnnplpplpp1µ11111W ... II 7OL1 &1EL\ FIG. 2. TOQNILA PLANNING DEPARTMENT 1975 AIRPORT • ATTACHMENT-"A" 6. contd. The Comprehensive Sewer Plan prepared for the City of Tukwila discusses the existing land use plan, existing and projected population growth within the existing service and planning areas, sewage flow and design criteria, the existing system, and proposed system expansion and improve- ments. Sewer system improvements include collection of wastewater and discharge to METRO or treatment. If actual land use and /or population' vary significantly from that used in preparation of the comprehensive plan, it would be necessary to reevaluate the size and location of proposed faci- lities. Some improvements would be provided as dictated by the demand for such facilities, while other needed improvements would be funded with funds on land and revenue bonds. In most cases, collection sewers would be financed by the developer. Wastewater treatment is performed at the METRO facility in Renton. 7. contd. Most of the attention is focused, however, on the 3.7 square miles presently within the City Limits and which presently is being sewered by Tukwila. This includes 2700 acres of alluvial lowlands lying west of the Green River, 2800 acres of glacial plateau, and 750 acres of steep wooded hillsides connecting the lowlands to the plateau area to the west. (See Chapter III of the Comp Plan for expanded description of the planning area). 11. contd. Green River and I -5 is shown to be served in this plan by Tukwila if the property so requires. This area can also be served by City of Kent. Relationship to Basin Wide Sewer Plan The existing and proposed sewer system for the City of Tukwila is dependent upon METRO accepting all sewage from the City for treatment and disposal. METRO is presently planning an enlargement to the Renton Treatment Plant and an outfall to Puget Sound to accomodate increased flows. The Comprehensive Sewer Plan will be updated and re- evaluated at least once every five years. Tukwila's plan is developed under the premise that METRO will continue its role for regional treatment and disposal for the metropolitan area. Relationship to Adjacent Cities and King County Plans With the exception of an area lying south of the present city limits of Tukwila between I -5 and the Duwamish River, this plan is consistent with the plans and service areas of the City of Kent and City of Renton. The service boundary on Tukwila's east side coincides with these municipalities. The Comprehensive Sewer Plan is consistent with Val Vue Sewer District which borders on the west side and presently no sewers exist in the areas north of Tukwila in Allentown. The Comprehensive Plan has been developed in compliance with the Tukwila Zoning and land use projections for the Service Area. • • Service Area Agreements Two areas of existing or future overlap exist. The first is an area of McMicken Heights lying inside the City and presently being served by Val Vue Sewer District. Agreements presently exist as discussed in detail within the Comprehensive Sewer Plan and they are adequate to govern service in this area. If substantial areas of McMicken Heights continue to annex to Tukwila, these agreements will be re- evaluated at such time regarding the possibility of taking over the sewers lying inside areas newly annexing to the City. The second area of .potential conflict is the South Service Area which is in the Tukwila Planning Area, presently in King County, and can feasibly be served by the Tukwila Sewer System with appropriate future system improvements. This area is also shown by the City of Kent as a possible future area they can serve. A portion of this area has already requested sewer service from Tukwila. Development Projects As it is impossible to predict the requirements of developers for service within individual undeveloped property, the construction of many facility improvements should be accomplished at such time that the request for service is received from the developer. Projects that benefit a local area could be accomplished by the LID method. The City or Sewer Department may assist funding these projects up to 25 percent. The actual schedule of these projects will be determined by' economic conditions each year. No attempt has been made to make any projection for specific improvements beyond the next five year period by which time all presently needed improvements would be under construction or completed. The need for further construction of sewer mains will be dependent on the actual growth and redevelopment rate except for those improvements that are requested by the developers. The Comprehensive Sewer Plan is not intended to precede growth, but rather reacts to the consequent needs of development. A review of the Comprehensive Plan should be made prior to the expiration of the five year planning period so that a specific program could be developed at that time if needed for further improvements. CITY OF TUKWILA COMPREHENSIVE SEWER PLAN SUMMARY AND RECOMMENDATIONS Purpose This summary is included to provide a concise synopsis of the key information presented in the City of Tukwila's Sewer Comprehensive Plan. It is intended to be presented in a non - technical manner. Recommendations are summarized and pre- sented in list form. (For further detail a copy of the complete Plan is on file at City of Tukwila, Public Works Department). Study Area The study includes all property within the Planning Area as defined by the Tukwila Planning Department which consists of approximately 9.8 square miles. Most of the attention is focused, however, on the 3.7 square miles presently within the City Limits and which presently is being sewered by Tukwila. A discussion and identification of the physical features, including geology, soil characteristics, surface water, ground water, lakes and ponds and existing development, is included in Chapter III of the Plan. Population and Land Use A detailed discussion is presented which defines the human environment, includ- ing existing land use and projected future growth scenarios. Three scenarios are developed as outlined below: Scenario 1 - Existing Conditions This is based on 1980 housing and employment figures. This scenario is to establish development conditions and population. • • Scenario 2 - Vacant Land Build -Out This scenario is developed according to the 1982 zoning ordinance by filling the vacant land to a total build - out condition. Scenario 3 - Redevelopment Build -Out This scenario assumes that portions of the planning area will redevelop to high intensity land uses and all vacant land will develop and infill to a higher intensity use. The number of residential houses, multi - family units, and square footage of build- ing for various types of development - retail, professional office, industrial/ warehouse, processing /manufacturing and open space - is projected for a various scenarios and given in Chapter III of the Plan. Resident population figures and employment figures are also derived for the various scenarios. These scenarios establish the base data for assessing the adequacy of the existing sewer system for each of the three conditions. Existing Sewer System The existing Tukwila sewer system consists of approximately 140,000 lineal feet of 6 -inch thru 24 -inch diameter sewer pipes, approximately 470 manholes and eight (8) pump stations. This system collects the sewage generated by the residences and buildings within the service area and transports it to METRO (Municipality of Metropolitan Seattle) pipelines. From these lines the sewage flows to the METRO- Renton treatment plant, where it is treated and discharged to the Duwamish River. METRO is presently in the development phase to increase the size of the Renton treatment plant and construct an outfall that would dis- charge the effluent directly to Puget Sound. A number of problems in the existing Tukwila sewer system have been identified including: heavy grease deposits in many of the pipes; some pipes have settled due to poor soils and have developed sags; some leak into and outof the system -2- • • have been identified; a few sewer lines are undersized for present or anticipated sewage flows; several pump stations should be eliminated while one needs to be enlarged or replaced. Other system improvements are needed as detailed in the Plan. In addition, pump stations have the potential and capability to overflow when a power outage occurs. Presently the City has no standby power units for any of their stations. Design Criteria Design Criteria, established in the Plan, is based on "Criteria for Sewage Works Design" by the State of Washington Department of Ecology. Criteria has been established to govern all future improvements to the system and provide for uniformity in design when sizing pipes and pump stations. It also will ensure a system that can be economically maintained by the City maintenance staff. System Analysis and Proposed Improvements A detailed engineering study was completed on a drainage basin -by -basin basis. Where data was available, a study was conducted to evaluate whether undesirable inflow from ground or surface water was robbing the existing pipes of needed capacity. This study is referred to as in Infiltration /Inflow Study. All past studies and television reports on internal inspection of the system were reviewed and included in system recommendations. The basin -by -basin study evaluated all defined alternatives where problems were discovered. A cost analysis, including associated maintenance costs, is included. Where preferred alternatives, either based on cost considerations, engineering reasons or maintenance reasons were defined, recommendations were made. In several basins, alternative recommendations were not specific. Where two solutions were relatively equal, both were included in the recommended improvement plan. All needed capital improvements are summarized in the Plan and shown on Figure 39 attached. -3- Implementation • Various funding alternatives to cover the needed improvement costs are discussed in detail in Chapter VII. Some of the needed sewer system improvements are eli- gible for a Washington State DOE Referendum 39 Construction Grant covering 50 percent of the eligible construction costs. It is recommended that a General Facilities Charge be imposed on all new buildings for development and property that redevelops. This charge is in lieu of the present regular connection charge and trunk sewer charge and would fund a portion of the neede improvements. A re- duction in monthly rates is included in this plan as outlined in the recommendations that follow. Additional funding for the needed improvements includes utilizing a portion of the $1,000,000 + presently available in the sewer fund. Ordinance changes are recommended to adopt more detailed requirements in establish- ing oil /grease separation, standards for private pump stations and other developer extension policies and requirements. Recommendations As a result of this study, the following recommendations and conclusions are made as part of the City of Tukwila's Comprehensive Sewer Plan: 1. It is recommended that the City adopt the Comprehensive Plan and Figure 39 attached as the plan which guides system improvements and new development. 2. It is recommended that Tukwila reduce City wide sewer rates and institute a General Facilities Charge for Needed Capital Improvements as detailed below. This facility charge would replace the present "regular connection charge" and ".trunk sewer charge ". Recommended Rate Reduction $1.00 per month per residential equivalent and $.50 per 100 cubic feet. -4- Recommended General Facility Charge Initially 8t /gross square foot floor area + 1t increase per year. Residence - $120 /residence + $12 /year increase. Multi -unit - $80 /unit + $10 /year increase. 3. It is recommended that Tukwila proceed with engineering design, studies and construction for Needed Capital Improvements, based on relative priority. Funding should be from existing cash on hand, grants and the General Facility Charge. Estimated Cost of Needed Improvements - $1,420,000 (Sewer Department portion) 4. It is recommended that Tukwila apply for D.O.E. Grant Funding for qualifying Needed Capital Improvements, and that the City closely monitor Referendum 39 funds and relative grant eligibility requirements. 5. It is recommended that Tukwila Public Works Department review all development plans before permitting buildings greater than 100,000 SF or heavy industrial uses generating more than 0.5 gallons /SF /day of sewage or process water. This review should insure compliance of such new developments with the spirit, intent and design principles of the Comprehensive Sewer Plan. 6. It is recommended that Tukwila develop a City wide operation and maintenance manual (0 & M Manual) and a developer extension manual as outlined in the Plan. 7. It is recommended that Tukwila adopt ordinances governing grease traps, and private pump stations and update ordinances governing new sewer extensions and services, as outlined in the Plan. 8. It is recommended that Tukwila extend sewer service to an area lying between I -5 and the Duwamish River and just south of the City Limits (South Service Area) if requests and applications by property owners are received. This area can be served at a reasonable cost to the property owners as discussed in the Plan. -5- • • 9. With the construction of the Needed Capital Improvements, man -hours required for maintenance should decrease slightly from present levels. This should help to free existing staff to accomplish necessary routine and preventive maintenance. We do not believe additional maintenance staffing is required to implement this plan. 10. It is recommended that Tukwila proceed with planning, procurement, design and construction of the miscellaneous recommended improvements as outlined in Chapter VI of the Comprehensive Sewer Plan. -9. With the construct of the Needed Capital Improv410hts, man -hours required for maintenance should decrease slightly from present levels. This should help to free existing staff to accomplish necessary routine and preventive maintenance. We do not believe additional maintenance staffing is required, to implement this plan. 10. It is recommended that Tukwila proceed with planning, procurement, design and construction of the miscellaneous recommended improvements as outlined in Chapter VI of the Comprehensive Sewer Plan. SYSTEM ANALYSIS AND PROPOSED IMPROVEMENTS General Information The existing sewer system was analyzed to evaluate the capacity of all existing sewer interceptors, laterals and pump stations with regard to both current domestic sewage flows and projected ultimate domestic sewage flows which may resulf from future growth. Where individual components of the system were inadequate, recommend- ations were made for reconstruction, elimination, diversion, zoning restrictions, infiltration /inflow rehabilitation, and /or more intensive studies. The recommenda- tions were based on a cost effective analysis of all defined alternatives. A needed capital improvement list which ranks the project in relative order of priority is attached. Areas which are not presently sewered (both existing franchises and possible annexa tions within the scope of the study) were analyzed to ascertain the most viable alternative for providing sewer service, and to determine the impact of serving these areas on downstream components. Needed improvements, which are downstream from other deficient parts of the system and which must be completed prior to upstream modifications, are noted as such in the Comp Plan. Notation is also made of those modifications which are of the most imminent nature. This provides an administrative tool to determine which individual projects should take priority. The first item studied in analyzing -6- .flows is infiltration/41/low within the existing system The study included analyzing existing flows where data was available, reviewing past studies, and past data on portions of the system that have been internally inspected by television. Infiltration /Inflow Analysis The purpose of the Infiltration /Inflow Study (I & I) is to review existing information and assess, where possible, if excess infiltration /inflow exists in specific sub - basins of the Tukwila Sewer System. Since observed I & I rates are well below the 1,100 gal /per /acre design value, it is concluded that I & I is not presently a serious problem for any of the pump station tributary areas studied. Sewage Pumping Considerations The City's eight (8) existing pump stations were analyzed not only for adequate capacity, but also for the possibility of elimination. The installation of sewage pump stations in the study area often provide the cheapest initial cost'solution for providing sanitary sewer service to an area. In light of the increasing concern for minimizing energy consumption, a greater awareness of the potential for sewage overflows and the escalating operation and maintenance costs of the installations, a higher priority is being placed on eliminating sewage pump stations wherever possible. Operation and Maintenance By far, the most serious problems in the Tukwila Sewer System are caused by grease deposits in side sewers, collector sewers, manholes, wet wells and force mains. Grease problems rob the Sewer Department of valuable time (including overtime charges) and equipment better spent on their ongoing system- wide preventative maintenance program. In addition, excessive grease entering the METRO trunk sewers violates METRO's sewer use ordinance and makes Tukwila vulner- able to legal action. -7- The Comp Plan recommendehe elimination of four (4) pullstations and the addition of many grease traps. Over 20,000 lineal feet of new sewer lines and force mains would also be added. Assuming these changes are made, no additional maintenance personnel should be required as the system expands due to the reduction in time consuming pump station maintenance and grease problems. Project for Cross Referencing Misc. Misc. Misc.• Misc. Misc. 3 4 9 TABLE 12 RECOMMENDED NEEDED CAPITAL IMPROVEMENTS Listed in Relative. Order of Priority Drainage Chapter Basin VI -52 N/A VI -52 N/A VI -52 N/A VI -52 N/A VI -53 N/A VI -11 2 VI -16 3 VI -23 8 12 VI -26 11 17' Misc. Misc. VI -40. 13 VI -54 VI -53 N/A N/A 20 VI -48 N /A. 20 Initial Pha'a VI -48 N/A 19 VI -43 - 13 10 VI -25 9 Primary Funding Project Description Cost Source Purchase 2 Portable Standby Power $ 70,000 Sewer Dept. 1 Install 6 Plug Adaptors for $ 24,000 Sewer Dept. 1 Portable Power Prepare 0 & M Manual for Entire $ 25,000 Sewer Dept. System & Developer Extension Manual Recommended Pump Station No. 1 $- 22,000 Sewer Dept. Improvements Install Bypass Connections for $ 24,000 Sewer Dept. 1 Pump Stations Eliminate Pump Station No. 4 $ 100,600 Sewer Dept. 1 Reroute Service Lines to $ 5,000 Sewer Dept. Haggards &. Riverside Inn Reconstruct Intruding Tee $ 3,000 Sewer Dept. at Southcenter Mall Eliminate Pump Station No. 3 Perform I/I Work, Reconstruct Sewers, Add Grease Trap, etc. Flush & T.V. Portion of System Not Completed 100,000 1.f. Upgrade Telemetering.System, Install Dialers, etc. Replace Pump Station No. 2 and Upgrade System Needed Capital .Improvements Gravity Sewer and Force Main to South Service Area 1,800' of 10" Sewer on Southcenter Parkway 500' of 8" & 150' of 15" Casing Along S. 158th. Street Under West Valley Highway VII -16 $ 115,300 Sewer Dept. 1 $ 68,500 Sewer Dept. $ 105,000 Sewer Dept. $ 30,000 Sewer Dept. $ 848,500 Sewer Dept. 1 $1,419,100 $1,197,500 Developer 1, 2 $ 104,400 Developer 2 $ 45,000 Developer 2 Project # for Cross Drainage Referencing Chapter Basin 13 VI -29 10 15A & 15B 2 VI -8 1 VI -8 TABLE 12 RECOMMENDED NEEDED CAPITAL IMPROVEMENTS (continued) Project Description 2,800' of 10" & 1,000' of 8" Sewer to Serve Basin 10 VI -34 13 Segale Business Park Revision Alternative I or III 1 Eliminate Pump Station No. 5 1 550' of 8" Sewer to Serve Allentown Addition 18A VI -41 13 Eliminate Pump Station No. 8 5 VI -18 3 3,000' of 8" Sewer on Beacon Coal Mine Road 6 & 6A VI -18 3 650' of 8 ", 300' of 15" Casing to Service Nielsen Dairy Property 7 VI -21 3 Eliminate Pump Station No. 6 16 VI -38 13 1,000' of 8" Sewer Along South 178th Street 11 VI -25 9 Install Grease Trap 14 VI -31 12 Install 2 Grease Traps (1) Grant Funds Possible (2) L.I.D. Possible VII -17 Cost $ 208,800 $ 38,000 $ 229,700 $ 52,600 $ 25,500 $ 170,500 $ 139,200 $ 73,700 $ _147,200 $ 46,400 $ 7,250 $ 14,500 Primary Funding Source Developer 2 Developer 2 Sewer Dept./ Developer 1 Developer Developer 1,2 Developer 2 Developer 2 Sewer Dept. 1 Developer Sewer Dept. Sewer Dept. K ING COUNTY VAL VUE • SEWER DISTR T • 8.- zOUn ST KENT C11T LINO CITY OF TUNWILA KING COUNTY ;emu, trams, wren 8 EP&YD €E€ VAL VUE SEWER DIST. ��II SETA L 1 PRIVATE PUM AT _PRMT •RENTON LEGEND --++- — METRO LINE • EXIST DAN. SLIVER . - -�••�' PROP. SAN. SEWER . FORCE MAIN PUMP STATION TUKWILA' CITY LIMIT LEE MRTCN Mt TOP £r • . FIGURE 39 AhIA`.f C WERINN SEPT. •. NSIN..MMMO•OTM.MTS•WATM■••■W \M• •OUILOINO• CITY OF TUKWILA COMPREHENSIVE SEWER .MAP a ©® • DETAIL "A" NE 12th ST. ; EDMONDS to OLYMPIA: LAIC E- ugaQZ -- . CI • Atra.fri • Qh„wN ScaNa 116«4., . Cry OR At+Oa, .;,;14o,41.0 1964 LEGEND KAMMrx. mu 1$ CITY iNn/ • DONLON L., nT • NTM*N AMT! • CLO$L C�GflO Wult PRISSIMI CEM'C all • Mllll _2_ - • MAP OF • • • C In- -of f2L'A'TO.\' • • WASH /NCTON . .lw_. oArt a v J)Ne 1962