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HomeMy WebLinkAboutSEPA EPIC-SA-8 - CITY OF TUKWILA - LOCAL IMPROVEMENT DISTRICT #24: SEWER AND WATER SYSTEM (LID #24)L.I.D. #24 SEWER AND WATER SYSTEM EPIGSA -8 • WILSEY & HAM, INC. Earl P. Wilsey (1892 -1957) 15 SOUTH GRADY WAY, EVERGREEN BUILDING • RENTON, WASHINGTON 98055 • Telephone (206) 228 -1080 • Cable "WHINT" April 9, 1974 File No. 3- 1605 - 2002 -30 Mr. Gary Crutchfield Planning Technician City of Tukwila 6230 Southcenter Boulevard Tukwila, Washington 98067 Dear Gary: We have reviewed the copies of comments by the agencies reviewing the Draft Environmental Impact Statement for the proposed LID #24.. For the most part the letters received can be considered incorporated by reference. The letter from the Department of Game raised some questions which required additional information, which is provided in the attachment. Thank you for the opportunity to be of assistance. Sincerely, WILSEY & HAM, INC. (—Au) A. Llewellyn Matthews Environmental Planner ALM /kb Attachment engineering • planning • surveying • landscape architecture • mapping • systems RESPONSE TO COMMENTS FROM THE DEPARTMENT OF GAME 1. The following additional information is provided in order to address . the concern that the proposed system could result in overburdening of the existing treatment plants, which consequently could result in water quality degradation elsewhere. (Paragraph 3). METRO reviews all such proposed facilities in order to determine if such a problem could occur. In this particular case, no problem is foreseen. Initially the effluent from the service area of the LID #24 will be routed through an existing interceptor line to the Renton Treatment Plant. For design purposes, the average flow from the total possible service area was determined to be 128,700 gallons per day (or approxi- mately 0.2 cfs). The Renton Treatment Plant which will receive the effluent has recently been modified in order to double its primary treatment capacity. Presently the Renton Treatment Plant has a primary capacity for 72 million gallons per day (mgd) during average dry weather. As a result of possible future modifications a capacity of 144 mgd could be achieved. During wet weather conditions, the Renton Treatment Plant presently has a hydraulic capacity (not treat- ment capacity) for 190 mgd. In the future a maximum wet weather volume of 375 mgd could be achieved. At some future date, as yet undetermined, the area to be serviced by the LID 24 will be picked up by a new interceptor line which will carry sewage to the West Point Treatment Plant for processing. The West Point Treatment Plant is currently constructed to capacity which is 125 mgd average dry weather conditions and 300 mgd during peak wet weather flows. Actually, lesser volumes are currently received at this plant. Advance treatment facilities for this plant are currently being studied in order to determine the best possible treatment in:light of the n$w standards. In sum, no capacity problems have been identified by METRO and all phases of the current systems are constantly monitored and studied in . terms of flows and water quality objectives. In regard to the concerns addressed in Paragraph 4, it should be noted that the project site is more identifiable as part of the Green River Valley walls than as valley bottom or floodplain. Also this site has been separated by highways from the area traditionally con- sidered as part of the Green River Valley flood plain. Although, as pointed out in your letter, "industrialization has not been determined conclusively as "favorable ", it is questionable to what extent policies governing industrialization on the flood plain are applicable to this site. Ultimately such questions are policy considerations. • • 3. In terms of runoff, the service area drains -into the natural drainage courses of the valley side and ultimately into the Green - Duwamish River. Paragraph 3 raises a concern for the effects of heavy indus- trialization on the water quality of the Green - Duwamish River. Provisions of sewer and water services will facilitate the conversion of a portion of the subject area from low density and open space to industrial and urban land uses. In general it can be said that runoff from street surfaces and paved areas is highly contaminated. In fact, it is similar in, many respects to sanitary sewage. "Calculations based on a hypotehetical but typical U.S. city indicate that the runoff from the first hour of a moderate -to -heavy storm (brief peaks to at least 1/2 in. /hour) would contribute considerable more pollutional load than would the same city's sanitary sewage during the same period of time, as indicated by the following table." CALCULATED QUANTITIES OF POLLUTANTS WHICH WOULD ENTER RECEIVING WATERS - HYPOTHETICAL CITY STREET SURFACE RUNOFF RAW SECONDARY (following SANITARY PLANT 1 hr storm) SEWAGE EFFLUENT (lb /hr) (lb /hr) (1b /hr) Settleable plus - Suspended Solids 560,000 1,300 130 BOD5 5,600 1,100 110 COD . 13,000 1,200 120 Kjeldahl nitrogen. 880 210 20 Phosphates 440. 50 2.5 Total Coliform Bacteria (org /hr) 4000 x 1010 460,000 x 10i0 4.6 x 1010 Source: Water Pollution Aspects of Street Surface Contaminants, 'Environmental Protection Technology Series, EPA -R2 -72 -081, November 1972. * Impervious Pervious LID 24 - PROJECTIONS OF WATER QUALITY CHANGE Concentration of Contaminants in Surface Runoff As A Result Of.A Typical Rainfall (0.1 inches /hour) WEATHER: SUMMER:. 3.33 Days - No Rain LAND USE Impervious Area) Industrial - Light Commercial WINTER: 1.24 Days. No Rain Low Low Density Industrial- Density Residential Light Commercial Residential 90% 1 90% BOD (mg /liter) Imp. *. 21.20 Per. 21.20 2.69 2.69 TOTAL COLIFORM (Org /100 ml) Imp.. 1,198,700 143,800 Per. 1,198,700 143,800 FECAL COLIFORM (org /100 m1) Imp. 20,400 • Per. 20,400 ORGANIC NITROGEN (mg /liter) Imp. .37 7.89 7.89 446,400 446,400 . 80 .80 53,600 53,600 4,300 ( 7,600 1,600 4,300 7,600 1,600 .21 . 1 .13 .08 .Per. 37 .21 .13 .08 AMMONIA (mg /liter Imp. Per. 10.87 10.87 . 108 . 108 4.05 4.05 NITRATE Imp. .13. .05 ,05 Per. 3.26 .16 1.21 PHOSPHATE (mg /liter) Imp. • 1.63 .. .22 .58 per_ '14 M 1 nL .04 .04 .02. . 06 .08 nn0 Other findings discussed in the above study indicate that the principal factors affecting the quantities of contaminants in the washoff include the following: surrounding land -use, the elapsed time since the streets.. or paved surfaces were last cleaned (either intentionally or by rain- fall), local traffic volume and character, street surface type and conditions, public works practices, season of the year, etc. In regard to industrial land use it was noted that industrial areas have sub- stantially heavier than average loadings. Industrial, areas experience greater spillage from vehicles, unpaved areas and streets in poor condition, etc. However, loadings vary widely between industrial sites. As part of a study undertaken by the River Basin Coordination Committee (RIBCO) a model was evolved whereby the water quality impact of the runoff from different types of land uses in the Puget Sound region can be protected. This model is particularly useful in order to gain an idea of water quality impact from runoff when a land use is changed. In the case of portions of the study area, land is undergoing a tran- sition from low - density residential to industrial. Varying amounts of pollutants were found to build up during dry periods on a typical acre depending on the land use. Then according to the intensity and duration of rainfall, a percentage of these pollutants will wash off. Thus, using the RIBCO model, the concentration of pollutants can be calculated for an average liter of runoff from the subject area, which ultimately reaches the Green - Duwamish River. The projections of pollutant concentrations can be performed for innumerable weather situations. However, for the purposes of this analysis, typical weather conditions were used. The National Weather Service recorded 25 days in December of 1973 in which 0.10 inches or more of rain fell and in June there were nine days in which 0.10 or more inches fell. So a typical summer situation might be one where there were 3.33 days of no rain followed by 0.10 inches of rain falling in one hour (see first column of chart). A typical winter situation might be one where there were 1.24 days of no rain followed by 0.10 inches or rain falling in one hour (see second column of chart). According to The Seattle Rain Gage Program and Rainstorm Data, by H.W. Duff and G.C.C. Hsieh. Oct 1507-71- 0.1 inches of rainfall will occur several times in a year. According to the RIBCO analysis, a:rainfall of 0.10 inches in an • hour will wash off 37% of the pollutants. Thus, the following formula was used in the water quality projections (see enclosed table) in order to determine the probable concentrations of contaminants of runoff: Acres x Number of Dry Days x Washoff Factor (37%) x RIBCO waste load factor . liters of runoff The data provided in the chart gives an indication of the relative magnitude of difference in the concentrations of pollutants in surface runoff that will result when land is used for industrial purposes as compared to low density residential purposes. Nutrients vary widely in the amount of increase that can be expected. The concentrations of ammonia and phosphates may also increase by about 10 times, however, the change in concentrations of organic nitrogen and nitrates may not be measureable.' At this point a few qualifications should be mentioned. The figures in the chart are average values for typical industrial and low density residential areas. At any given time pollutants measured in runoff from the subject area may vary considerably depending on the weather, and localized on -site activities. Also, portions of the study area are already industrial and additional portions are under construction. However, it is not anticipated that all of the area which could ultim- ately be served by the LID will be used for industrial purposes. Portions will remain residential. Thus, these figures do not mean that the water quality of runoff from the study area as a whole will be ten times more deletrious, but rather they are a general indication of the change in the water quality when a given area is converted from low density residential to industrial purposes. Frank Todd, Mayor CITY or TUKWIL' 6230SOUTHCENTER BLVD. TUKWILA, WASHINGTON 98067 PLANNING DEPARTMENT Wilsey &._Ham, Inc. r Mr. Mike Brooks Evergreen Building 15 South Grady Way Renton, Washington '98055 Dear Mike: - Please find enclosed copies of all comments received in response to. the Draft Environmental Impact Statement prepared by your firm for the proposed L.I.D. #24 within the City of Tukwila. As you are aware, these comments and their respective responses should be incorporated into the Draft Statement and returned to this office for acceptance as the Final. Environmental Impact Statement. Please do not hesitate to contact me should you have any questions regarding this matter. Sincerely, GC /lt Ga • Crutchf Planning Technician Encl: 1. Ltr, PSAPCA, dtd 7 March 74 2. Ltr, Dept of Game, dtd 14 March 74 3. Ltr, Dept of Soc & Hlth Svcs, dtd 15 March 74. 4. Ltr, Region X EPA, dtd 12 March 74 5. Ltr, Office of. Comm Dev, dtd 5 March 74 6. Ltr, Pks &.Rec Comm, dtd 27 Feb 74 7. Ltr, PSGC, dtd 21 Feb 74 8. Ltr, State Hwy Comm, 11 March 74 DANIEL J. EVANS GOVERNOR • DEPARTMENT OF SOCIAL AND HEALTH SERVICES CHARLES R. MORRIS Gary Crutchfield Planning Department City of Tukwila 6230 Southcenter Boulevard Tukwila, Washington 98067 Dear Mr. Crutchfield: SECRETARY HEALTH SERVICES DIVISION P. O. BOX 1788. OLYMPIA, WASHINGTON 98504 March 15, 1974 Re: DRAFT ENVIRONMENTAL IMPACT STATEMENT LOCAL IMPROVEMENT DISTRICT 24 SEWER AND WATER SYSTEM Mail Stop 4 -1 JOHN A. BEARE. M.D. Director We have reviewed the above referenced statement and deduce that the environmental health issues of concern to this agency have been satisfied. Very truly yours, OFFICE OF ENVIRONMENTAL HEALTH PROGRAMS A ,4e JOHN H. LAUBACH, R.S. Acting Administrative Consultant JHL :blm • Director / Carl N. Crouse Assistant Directors / Ralph W. Larson Ronald N. Andrews Game Z'ommission Arthur S. Coln, Yakima, Chairman James R. Agen, LaConner Elmer G. Gerken, Quincy Claude Bekins, Seattle Glenn Galbraith, W/ellpinit Frank L. Cassidy, Jr., Vancouver DE PARTMENT OF' GAME 600 North Capitol Way / Olympia, Washington 98504 March 14, 1974 Gary Crutchfield Planning Technician City of Tukwila 6230 Southcenter Blvd. Tukwila, Washington 98067 Dear Mr. Crutchfield: Your draft environmental impact statement - Local Improvement District No. 24 Sewer and Water System - was reviewed as requested, comments follow. You have provided an unusually clear, well- documented and complete report of this proposed action. As was pointed out, minimal adverse effects to wildlife should be .sustained through construction activities, due to lines being laid in existing right -of -ways generally devoid of wildlife habitat. Concurrently, water quality of the small streams traversing the project site should improve as overloaded and ineffective septic systems are eliminated, which in turn will ultimately contribute to an overall improvement of the Duwamish -Green River waterway. We do, however, have a few general comments on the assessment provided in your statement. We would like to know the type, location, and present load capacity of the city sewage treatment facilities, and location of final discharge of sewage effluent. This is necessary to determine whether the proposed system will result in overburdening of the existing treatment plants, which would consequently result in water quality degradation elsewhere. This is especially important in light of the stated secondary impact of the action, increased industrial and urban development. This system appears to be designed and intimately related to future industrial expansion. However, present landowners, including a substantial percentage of low- income families, will be assessed for costs of improvement. Thus, they could be effectively forced out of the area, which will further enhance possibilities for industrialization. Industrialization of the Green River Valley Flood Plain has not been determined conclusively as "favorable in fact it is inconsistent with regional land -use plans developed by,Ruget Sound Governmental Conference, (page 10). If this sewer and water system is designed for anticipated industrial expansion, rather than to accomodate present and projected residential development, we suggest that an alternate means of assessment be arranged to alleviate this imbalance between residential and industrial needs for sewage and water facilities. Concern for the Gary Crutchfield • • -2- March 14, 1974 Duwamish -Green River water quality should include consideration of effects heavy industrialization within its flood plains will have on its waters. We concur with your assessment of direct impacts on terrestrial and avian wildlife. However, we were disappointed by the omission of discussion of secondary impacts on these species. The greatest losses to wildlife which have taken place - and will continue to occur - have been precipitated by projects which lead to elimination or deterioration of habitats. This should be acknowledgedin your draft. Along with this we urge that serious consideration be given to protection, or at least mitigation, of remaining habitats and natural values. Thank you for the opportunity to comment on your draft statement. We appreciate the extensive charts, tables, and inventory analysis given, and hope our comments will be of help in preparation of your final statement. ESD:jb cc: Chitwood Agencies Sincerely, FcVt THE DEPARTMENT OF G E . t Eugene S. Dziedzic, Asst. Chief Environmental Management Division • Director / Carl N. Crouse Assistant Directors.- / Ralph 11 ". Larson Ronald N. Andrews • Game Commission Arthur S. Collin, Yakima, Chairman James R. A,en, LaConner Elmer G. Gerken, Quincy Claude Eekins, Seattle • Glenn Galbraith, lVs!lpinit Frank L. Ca.uidy, Je., Vancouver 33M 1A3R.'r -{U isTrr ®P' a".A.M� 600 North Capitol Way / Olympia, Washington 98504 March 14, 1974 Gary Crutchfield Planning Technician. City of Tukwila 6230 Southcenter Blvd.. Tukwila, Washington 98067 Dear Mr. Crutchfield: ECHVE MAR 1 9 1974 CE /iY.�F ilD Your draft environmental impact statement - Local Improvement District No. 24 Sewer and Water System - was reviewed as requested, comments follow. You have provided an unusually clear, well- documented and complete report of this proposed action. As was pointed out, minimal adverse effects to wildlife should be sustained through construction activities, due to lines being laid in existing right -of -ways generally devoid of wildlife habitat. Concurrently; water quality of the small streams traversing the project site should improve as overloaded and ineffective septic systems are eliminated, which in turn will ultimately contribute to an overall improvement of.the Duwamish -Green River waterway. We do, however, have a few genera on the essment prorded in your st�.ement. T E'TQ9 rJ-r- , C U4t (tb� Lor�t ) (1 too€. We -woui d - - -1 -i ke to know -"the -type , location -, and present l oad capacity of-the ci ty= sewage- treatment facilities? and - location - of f i nal_-di schar-ge of sewage effluent. This is necessary to determine whether the proposed system will result in overburdening of the existing treatment plants, which would consequently result in water. quality degradation elsewhere. This is especially important in light of the stated secondary impact of the action, increased industrial and urban development. �.- ` 7S r c, rvc12 F0 rz r4 Ar i rru 00(104-,0 r tm 1 This - -sy tem .,appears tobe designed__and intimately- related io future industrial-'expansion .' However, present - landowners, including a substantial percentage of low- income families, will be assessed for costs of improvement. Thus, they could he effectively forced out of the area, which will further enhance possibilities for industrialization. Industrialization of the Green River Valley Flood Plain has not been determined conclusively as "favorable "; in fact it is inconsistent with regional land -use plans developed by Puget Sound Governmental Conference, (page 10). If this sewer and water system is designed for anticipated industrial expansion, rather than to accomodate present and projected residential development, cwe==sugges-t- -that.: ,all-alternate -means.--of assessment -be_.ar_ranged to alleviate this imbalance between residential and industrial needs for sewage and water facilities. Concern for the NNo 1 LEEnLIy (3E. O Ne ut i2 T L.rluoS (c»3) Gary Crutchfield -2- March 14, 1974 Duwarnish -Green River water quality should include consideration of effects heavy industrialization within its flood plains will have on its waters. We concur with your assessment of direct impacts on terrestrial and avian wildlife. However, we were disappointed by the omission of discussion of secondary impacts on these species. The greatest losses to wildlife which have taken place - and will continue to occur - have been precipitated by projects which lead to elimination or deterioration of habitats. This should be acknowledgelin your draft. Along with this we urge that serious consideration be given to protection, or at least mitigation, of remaining habitats and natural values. Thank you for the opportunity to comment on your draft statement. We appreciate the extensive charts, tables, and inventory analysis given, and hope our comments will be of help in preparation of your final statement. Sincerely, THE DEPARTMENT OF G E P ESD:jb cc: Chitwood Agencies 0Ci Eugene S. Dziedzic, Asst. Chief Environmental Management Division U.S. ENVIRONMENTAL PROTECTION AGENCY �\iv) STgT� REGION X J s =ni A "6 1200 SIXTH AVENUE A1101 W SEATTLE, WASHINGTON 98101 Z Q March 12, 1974 q. PRO- REPLY TO ATTN OF: 10MEI - M/S 325 Mr. Gary Crutchfield Planning Techni ci an, City of Tukwila 6230 Southcenter:Boulevard Tukwila, Washington. 98067 Dear Mr. Crutchfield: We have made cursory review of your .draft environmental impact statement, "Local Improvement District No. 24 Sewer. and Water. System. ". We have found no major adverse environmental impacts in our areas of expertise. Thank you for the opportunity to comment on this draft statement. Si ncerely,. Hurion C. Ray .(gC‘a Assistant Regional Administrator for Management WASHINGTON STATE • HIGHWAY COMMISSION DEPARTMENT OF HIGHWAYS Highway Administration Building Olympia, Washington 96504 (206) 753 -6005 City of Tukwila Planning Department 6230 Southcenter Blvd. Tukwila, Washington 98067 Attn: Mr. Gary Crutchfield Planning Technician Dear Mr. Crutchfield: Daniel 1. Evans - Governor G.H. Andrews - Director March 11, .1974 City of Tukwila L.IL,D, No. 24 Sewer and Water System Draft Environmental Statement Reference has been made to your transmittal letter dated February 15, 1974, requesting our review of the Draft Environmental Statement for the above referenced project. We have completed our review and find no conflict with any existing or proposed highway facilities in this area. Thank you for the opportunity to review this information. Sincerely, GHA:eh HRG A. H. Parker Chairman Bremerton G. H. ANDREWS Director of Highways By: H. R. G Assistant Director for Planning, Research and State Aid Harold Walsh Baker Ferguson Virginia K. Gunby Howard Sorensen Harold L. Boulac Everett Walla Walla Seattle Ellensberg secretary SERVING: KING COUNTY 410 West Harrison St. Seattle, 98119 (206) 344 -7330 KITSAP COUNTY Dial Operator for Toll Free Number Zenith 8385 Bainbridge Island, Dial 344 -7330 PIERCE COUNTY 213 Hess Building Tacoma, 98402 (206) 383 -5851 SNOHOMISH COUNTY 506 Medical - Dental Bldg. Everett, 98201 (206) 259 -0288 PUGET SOUND AIR POLLUTION CONTROL AGENCY Mr. Gary Crutchfield Planning Technician • City. ;of.Tukwila 623.0 sBoUthcenter Tukw.i•la, Wa. 98067 • 410 West Harrison Street, Seattle, Washington 98119 (206) 344-7330 March; 7 , 1.974 • Subje :ct:. Local Improvement District -24 . .Sewer and Water. System:. Draft Environmental Impact Statement Dear Mr. Crutchfield: We .have: reviewed your draft environeMntal. 'impact statement . for the Local Impr.ovemen.t. District- 24...sewer and water sys- tem•s.ubmitt.e.d. with your letter .. of.February.15,.197.4.. • Our comments, .limited to. air .quality. aspects. of the proposal, are. listed below: 1. We. note that the .proposal has indicated the need for Notice. of Construction applications for any new or altered air contaminant sources (:summary page and page 11). :2.. Lift station odors may be controlled by a variety of means. We .'would direct :your attention -to several re_ late.d. articles on the attached list,. with which. you may. be 'familiar._ 3: We note. also that precautions for dust :suppression - are .planned. to be. taken during the .constr.uction. of the .proposed project to: prevent violations of Regu- lation I (pages... 62 and 66).. If you have any questions regarding these remarks please contact us. ARD:JKA:mfr. Attachment Your truly, A. R. iammkoehler Air Pollution Control Officer. BOARD OF DIRECTORS CHAIRMAN: Gene Lobe, Commissioner Kitsap County; VICE CHAIRMAN: Gordon N. Johnston, Mayor Tacoma; N. Richard Forsgren, Commissioner Snohomish County; Patrick J. Gallagher, Commissioner Pierce County; Harvey S. Poll, Member at Large; John D. Spellman, King County Executive; Wes Uhlman, Mayor Seattle; Robert C. Anderson, Mayor Everett; Glenn K. Jarstad, Mayor Bremerton; A. R. Dammkoehler, Air Pollution Control Officer. DANIEL J. EVANS GOVERNOR • • STATE OF WASHINGTON Office of the Governor OFFICE OF COMMUNITY DEVELOPMENT OLYMPIA. WASHINGTON 98504 206/753.2200 RICHARD W. HEMSTAD DIRECTOR March 5, 1974 #395 Mr. Gary Crutchfield 6230 Southcenter Blvd. Tukwila, Washington 98067 Dear Mr. Crutchfield: This letter is to acknowledge receipt of your environmental impact statement on your LID #24 Sewer and Water System. The statement title has been circulated among all Divisions within this agency. We have no comment on the statement at this time. Sincerely, Nick Pettit, Policy Analyst Policy & Planning Division NP:ib 3 GOVERNOR DANIEL J. EVANS COMMISSIONERS: MRS. KAY GREEN JEFF D. DOMASKIN THOMAS C. GARRETT RALPH E. MACKEY JAMES G. McCURDY JAMES W. WHITTAKER WILFRED R. WOODS DIRECTOR CHARLES H. ODEGAARD WASHINGTON STATE PARKS & RECREATION COMMISSION LOCATION: THURSTON AIRDUSTRIAL CENTER P. O. BOX 1128 February 27, 1974 PHONE 753 -5755 OLYMPIA, WASHINGTON 98504 Mr. Gary Crutchfield Planning Technician Planning Department 6230 Southcenter Boulevard Tukwila, Washington 98067 Draft Environmental Impact Statement - Local Improvement District No. 24 Sewer and Water System - Tukwila Dear Mr. Crutchfield: The Washington State Parks and Recreation Commission has reviewed the above noted draft environmental impact statement and does not wish to make any comment at this time. Thank you for the opportunity to review and comment. Sincerely, David W. Heiser Assistant Chief, Research, Planning and Acquisition cbm Exno°711 3 PSGC February 21, 1974 • • Grand Central on the Park 0 First and So. Main • Seattle, Washington 98104 • 206/464 -7090 Puget Sound Governmental Conference Gary Crutchfield, Planning Technician City of Tukwila, Planning Dept. 6230 Southcenter Blvd. Tukwila, Washington 98067 Subject: Local Improvement District No. 24, Sewer & Water System, Tukwila. Dear Mr. Crutchfield: The Puget Sound Governmental Conference has received your Draft Environ.menta.l Impact Statement submitted for comments pursuant to the State Environmental Policy Act. Log number 2/101 /74 was assigned to this Impact Statement on February 22, 1974 . It will be helpful if you refer to this number during any future correspondence. A thirty day period is allocated for review of your Draft Environmental Impact Statement. During this period the Conference will review and comment on your impact Statement, and solicit review comments from potentially affected localities and agencies. The purpose of this review is to insure that presently unquantified environmental amenities and values will be given appropriate consideration in decision making, along with economic and technical considerations. Mr. Dave Kalberer (phone: 464 -6873 ) will be responsible for the review and local coordination of your Draft Environmental Impact Statement. Copies of the formal clearinghouse comments will be transmitted to you, the state clearinghouse, the appropriate funding agency, and the State Department of Ecology for their consideration. The review of your Impact Statement will follow the procedures stipulated within the 'Federal Aid Review Procedure Manual' published by the Puget Sound Governmental Conference. Mart Kask Executive Director MK: RLMc C: h.c PSGC Form R -6 (Revised 12/27/1972) • • Frank Todd, Mayor CITY of TUKWILA 6230 SOUTHCENTER BLVD. TUKWI LA, WASHINGTON 98067 PLANNING DEPARTMENT Gentlemen: 15 February 1974 Please find enclosed herewith a copy of the Environ- mental Impact Statement prepared for a project entitled Local Improvement District No. 24 Sewer and Water System to be located within the corporate limits of Tukwila. The statement has been reviewed by this office in accordance with the National and State Environmental Policy Acts as well as in regard to Federal, State regional and local plans and programs. This office would appreciate any comments regarding this Statement within thirty (30) days from date of this letter. Please relate your comments in writing and direct them to this office at 6230 Southcenter Boulevard, Tukwila, Washington 98067. It Sincerely, Gary Crutchfield Planning Technician Sewer & Water System. Air Quality Control References Hicks, Ronald. "Odor Control in Waste. -Water Treatment Systems". Proc`eed.ings of. 'The' 'Second International 'Clean Air Congress. Academy Press. New York, 1971. Pages 867 -87.6. McKenzie, Donald. "Burn Up Those lift- Station Odors". The 'American 'City. November, 196.6. Pages 80 -82.. Sullivan, Ralph J. Preliminary Air Pollution Survey of Odorous Conipounds .' A Literature 'Review. U.S. Dept . of Health, Education, and Welfar.e.' Raleigh. October 1969. (Pages 75 -77, 98 -99, 162.). Ullrich, A. H. and Ruff, R. J. "Oxidation of Sewage Odors. Catalytic Combustion Co. Detroit. CITY OF TUKWILA DRAFT ENVIRONMENTAL IMPACT STATEMENT FOR APPROVAL OF LOCAL IMPROVEMENT DISTRICT 24 SEWER AND WATER SYSTEM PURSUANT TO WASHINGTON STATE ENVIRONMENTAL POLICY ACT OF 1971 CHAPTER 43.21C RCW CITYOF TUKWILA, WASHINGTON ORDINANCE NO. 759 WILSEYBHAM RENTOIa. WASH. SUMMARY SHEET Nature of this Report: Draft Environmental Statement Sponsor: City of Tukwila 6230 Southcenter Boulevard Tukwila, Washington 98067 Type of Action: Administrative decisions by the City of Tukwila in order to provide sanitary sewers and water service for Local Improvement District 24. Other Official Review, Approvals, and Permits: 1. Building Permit. 2. Review of the State Department of Ecology Flood Control Zone Permit by the City Works Director. 3. Permit from METRO to connect to the METRO System. 4. Permit to cross the Puget Sound Power and Light easement. 5. Permit to cross under the State Highway Department. 6. Notice of construction and application for approval in order for Puget Sound Air Pollution Control Agency to evaluate when the activity will meet PSAPCA Regulation 1. 7. Possible future extensions may require additional permits to cross road easements. Summary of Environmental Impacts a. Noise and Atmospheric Impact Temporary increases in noise levels can be expected during construc- tion activities. Dust created during all phases of the project can be adequately controlled and is not likely to become a nuisance. Atmospheric conditions should not be significantly impacted by construction of the proposed project. b. Geological Impact The construction of the proposed sewer and water lines will require excavation averaging 12 feet and 4 feet respectively. The topography of the service area will be altered when additional development occurs, which in many cases will require filling. c. Hydrological and Water Quality Impacts During the construction phases, short -term impacts will be associated with the dewatering of the soil along the proposed sewer and water routes. Long -term impact of the construction activities on ground- water is expected to be minimal. Long -term water quality conditions will improve as additional industrial and residential areas are sewered and septic tank overflows are eliminated. d. Biological Impact Inasmuch as the proposed sewer and water lines will be placed within the existing roadways and roadway right - of-ways, minimal disruption to existing natural systems will occur. e. Social Impacts Provision of sewer and water service will allow for industrial develop- ment within the area included within the proposed Local Improvement District which may stimulate further urban growth. DRAFT ENVIRONMENTAL IMPACT STATEMENT FOR APPROVAL OF LOCAL IMPROVEMENT DISTRICT -24 SEWER AND WATER SYSTEM PURSUANT TO WASHINGTON STATE ENVIRONMENTAL POLICY ACT OF 1971 RCW 43.21 c CITY OF TUKWILA, WASHINGTON ORDINANCE NO. 759 A. THE PROPOSED ACTION 1. Type of Action The City of Tukwila will undertake administrative action and approval procedures in order to provide sanitary sewers and water service for Local Improvement District 24, hereafter referred to as the proposed LID, located within Tukwila, Washington. 2. Location (Refer to Location Map, Figure A) The proposed sewer and water systems will service an area located within the corporate limits of the City of Tukwila. State Highway 599 separates the service area from the rest of the city. Interurban Avenue South and East Marginal Way provide local access to this corner of Tukwila. Beyond the city limits of Tukwila are several unincorporated neighborhoods including Riverton and Foster. The Green - Duwamish River flows less than one - quarter a mile away. (See Appendix for boundary description.) 3. Development Resulting from the Proposed Action (See Figures B & C) The proposed action will result . in sewer and water service to an initial area within the corporate limits of the City of Tukwila and ultimately to portions of an adjacent area of King County. Service will be provided to the land within the proposed LID boundaries which encompasses approximately 20.6 acres including streets and dedicated rights -of -ways. During the second phase, an additional 26.3 acres within Tukwila could be served by the proposed sewer and water improvements. Also, over 21 acres of King County within the Val -Vue Sewer District could ultimately be served by the proposed system. The following description of the proposed sewer and water improvements is related primarily to the first phase of construction. Design for the second phase and ultimate extensions have not been developed. a. Sewer Improvement - Gravity Collection System With A Centrally Located Lift Station. A lift station will be located in the triangle formed by the intersection of South 133rd Street and South 134th Street. The station will be located in the triangular island area of the intersection on the premise that this area might eventually become a landscaped island under an overall area development. -1- LEGEND ' Tukwila City Llmite r_ra L. D. 24 Boundary ' , �.� Vol - Vus Sewer Dist (Service Limits) Son. Sewer Line Ban. Sewer Force Main Qo Manholes © LItt Station Future Contribution From Vd -Vue District Mph.. Ousher 7.l• M. VAL— VUE SEWER DISTRICT Figure B Sewer System Improvement -3- fe+vrl A Fiow:� LEGEND ---- -� ---� Tukwila City Limit L.1.0 24 Boundary - •- •- • —• -• -• Water Dist. 35 B 38 — w— 'Proposed Water Line - - -- Future Water Line Extension ® Butterfly Volvo ' !K Fire Hydrant (54.14.y0.1 Ca., ce (540c Mesa ., • /20- /SOH'./ sD N —� 35 WATER Figure C Water System Improvement -4- The lift station will be an underground structure with the access housing (including the electrical control panel) being the onlyabove ground projection. The gravity collection system will project generally northwest and southeasterly along South 134th Street; however, the restricted access provisions along the northwest side of South 133rd Street indicated more flexible land use planning to the northwest if the gravity sewer were not routed directly northwesterly on South 134th Street. For this reason the sewer was routed approximately 400 feet westerly along South 133rd Street and thence northerly along the connecting street and back to South 134th Street. Although this routing,adds a short run of main line to the improvement, the ultimate system will be reduced in length because a future extension westerly to serve future areas will not be required. It is anticipated that low areas to the Northeast of South 134th Street will require filling and re- contouring of the surface to accommodate industrial development. The depths of this fill are not determinable at this time nor is a development plan of the affected areas available. The elevations of the sewer system have been set to provide service to all areas with reasonable depth of land fill in the low areas. Most of the land in the low areas will need fill in order to support more intensive use. The Val-Vue Sewer District has indicated a limit of future service area as shown on Figure B. Two small areas totaling approximately 24.5 acres, within the Val -Vue Sewer District can be served by the recommended system through gravity sewer con- nections. These two small areas constitute the ultimate service area of the proposed LID improvements. If these two areas were to be served by the Val -Vue District, by agreement with the City of Tukwila, be permitted to connect to the proposed system at their cost. Suitable charges for the lift station operation and maintenance would be determined as the connections are made, however, no increases in pipe sizes would be required to serve these areas. b. Domestic Water Improvement - A Looped System The proposed water system is the first of a staged program to provide service to the areas in the proposed LID. A subsequent extension of this system would provide an additional connection to the City system and provide a looped supply such that a breakdown in either connection would not completely shut down the system throughout the area. For the same reasons as the proposed routing of the sewer system, the water system has been routed westerly on South 133rd Street and northerly on the connecting street to South 134th Street. Because of the extensive area southwest of South 134th Street, it is suggested that development of this area will require an internal fire protection system. Therefore, an 8-inch main has -5- been indicated as a future stage loop through the area, with final locations and alignment to be determined as development progresses. Additional looping of mains through the low areas northeast of South 134th Street may also be desirable in the future. The area south of South 133rd Street lies within the service area of Water District 35. Portions of the area are presently served by this district; however, main sizes are too small to provide adequate water for domestic consumption and fire protection as the area develops. The areas north and west of South 133rd Street are presently being serviced by Water District 38; however, these areas are outside the water district boundary. The main sizes are also too small to provide adequate water for domestic consumption and fire protection as the area develops. The age and condition of the existing systems is largely indeterminate at this time, and any cross - connections between the existing systems and the proposed system could present problems in the older lines. For these reasons the proposed system will probably be constructed to operate independently of existing facilities.. Fire hydrants have been located approximately 300 feet apart and staggered on opposite sides of the streets where possible. Future extensions and loops will be provided with fire hydrants in conformance with City requirements. 4. Justification For the Proposed Action The proposed action is in accordance with and represents the lawful implementation of previously. determined City of Tukwila policies as embodied within official plans, ordinances and resolutions (to be discussed later). The proposed sewer system and water facilities represent a necessary step in the development of this portion of the City of Tukwila. Two of the land owners within the proposed LID entered into a Developer's Agreement with the City of Tukwila spec- ifying that the area represented by the proposed LID would be sewered as soon as possible. At the present time two industrial establishments have no effective septic tank drainfields and utilize holding tanks in which waste water is collected until disposal. This situation will be alleviated and constraints to future development within this portion of the City of Tukwila will be removed by the construction of sewers and water facilities. 5 Proposed Method of Financing and Financial Sponsors The costs and expenses of the proposed improvements are distributed and assessed against all property in the LID according to the resulting benefits (R.C.W. 35.43.220). For assessment purposes, the costs to each landowner may be distributed according to the number of square feet or property owned, or according to the length of frontage on adjacent roads. In the present case, assessment for the sewer and water facilities will be determined on a square footage basis. The total project cost of the trunk facilities will be calculated (12" water -6- transmission main, sewage lift station and force main). The cost of these trunk facilities will be spread equally throughout the total service area. The total project cost of the service lines to be constructed during the first phase will be calculated and this total cost will be spread on a zone basis to all lands within the proposed LID. The City of Tukwila will finance that portion of the total project cost of the trunk facilities which lies outside the LID boundary and recover this cost as future areas connect to the system. Preliminary cost estimates and preliminary assessments are included in Appendix. 6. Historical Background and Past Planning Decisions a. Land Use The subject area lies adjacent to the lower Green River Valley Flood Plain. Farming began in.the Nineteenth Century with dairying as the predominant land use in the valley. Truck farming was also carried on, but high water table and poor drainage minimized this use. Agricultural use remained dominant until the 1950's when industrialization of the valley lands began. This industrial growth was stimulated by a number of factors, but one of the most important was the proximity of transportation systems which have historically been routed through the Green River Valley. Geography sets severe constraints on the location of transportation routes in the Puget Sound Region. Seattle responded to the early predominance of Tacoma as the major railroad terminus on Puget Sound with the building of the Seattle and Spokane Railroad Line, which later became part of the Chicago, Milwaukee, St. Paul and Pacific Railroad's main line up through the Duwamish,and the lower Green and Maple Valleys. In the late 1800's and early 1900's other railroads, i.e., the Northern Pacific and Great Northern, and the Milwaukee and Union Pacific built nearly parallel tracks through the Green River Valley on routes connecting Tacoma and Seattle. These railroads were supplemented by a system of highways constructed in the first quarter of this century. The industrial growth of the City of Tukwila has related closely to the growth and economic prosperity of the Seattle Metropolitan Area. At the time of incorporation in 1908, Tukwila was a small, thriving trade center astride the main Seattle - Tacoma Highway, but construction of alternate routes by- passing Tukwila, the East and West Highways and Route 99, left this town with a declining commercial base. The construction of two interstate freeways converging in Tukwila provided excellent accessibility, to the study area. -7- The move toward industrial development in the valley began when planners for the Port of Seattle suggested an ambitious scheme to turn the Duwamish and Green River Valleys into a large indus- trial complex complete with a shipping canal to service the area. Local communities countered this proposal by annexing large land areas and imposing their own industrial zoning on the land. Tukwila, for example, annexed a large area of bottom land to the south of the city as well as the area in the northwest of the city, of which the proposed LID is a part. This industrial zoning in the valley, plus high increases in residential and commercial development on the adjacent hillsides, and the subsequent building of the freeway system (again to some extent dictated by geographic and topographic features), all contributed to the present rush of industrial and commercial development that is not expected to abate for several more years. , Relationship to Existing Laws, Policies, and Plans a. Policies and Plans Prior to annexation by Tukwila, King County Land Use Policies and Plans applied to the proposed LID and its potential service area. The following policies were developed which committed the entire area to low density residential uses: 1) Residential areas should be encouraged to develop primarily in plateaus and gentle slope areas rather than in river valleys 2) Land which is suitable for _residential use in terms of physical characteristics, but which is beyond the fore- seeable urban area, should be considered as a residential reserve and be subject to special analysis to determine proper timing of urban type development. Accordingly, the area now comprising the proposed LID and its potential service area were zoned "SR ", suburban residential by King County. The purpose of this zoning designation is to provide for the orderly transition of areas from a suburban to an urban character. Within this classification, small scale and intensive agricultural pursuits may be mixed with developing urban subdivision. The existing trend of land use, a transition from residential uses to industrial uses, reflects the previous zoning. County areas adjacent to Tukwila are presently zoned for low density residential purposes. By . way of incidental note, the following King County Industrial Development Policies would have applied to the proposed LID and potential service area had this area remained under county jurisdiction: -8- 1) Space for industries should be reasonably scaled to demonstrated demand and need. 2) Industrial areas shall be encouraged to develop primarily on large level sites. Prime level agricultural land shall be subject to special analysis to determine proper timing of use change in order to avoid permature curtailment of agricultural production and loss of permanent open space. 3) In order that residential areas may be free from industrial traffic, industrial areas shall be located with access provided to major transportation routes which include major arterial truck routes, expressways, freeways, major rail lines and navigable bodies of water. 4) Industrial areas should be located where they can be adequately served by necessary major utility lines, such as electric power stations and transmission lines, and trunk gas lines. The proposed sewer and water system will facilitate industrial growth within the proposed LID and possibly will allow for more intensive use of the adjoining areas as well. Industrial use of the proposed LID is consistent with local land use policies, plans, and zoning. The Tukwila Comprehensive Plan notes that Tukwila is part of the Seattle Metropolitan area, and its growth is predicated on the continued growth and prosperity of this larger region. Tukwila is becoming a major commercial and light industrial center and is serving a regional market with the construction of several industrial parks and the Southcenter Regional Shopping Center. The Tukwila Comprehensive Plan, adopted in 1962, provides the basic rationale for development along the Green and Duwamish Rivers. This plan is still in effect today. At the time of adoption, the Tukwila Comprehensive Plan recommended use of the Green River Valley Flood Plain for industrial purposes. It was noted that while filling and other expensive site preparation activities are usually necessary to develop these valley - bottom sites, large, valuable flat industrial sites can be created. As noted previously, several industrial parks and a regional shopping center have-been built within the last six years. Development on most of the remaining Green River Valley sites will probably occur in the near futre. The northwest portion of Tukwila, which lies in and adjacent to the Duwamish River Flood Plain, and containing the proposed LID thereafter this area was zoned "M -1 ", Industrial. This zoning classification has remained in effect to the present time. The same land use policies which have guided development in the Green River Valley bottom lands were also applied to the LID and its potential service area. -9- Industrial land use within the proposed LID, which will be fac- ilitated by sewer and water service, is however, inconsistent with current regional plans. The Puget Sound Governmental Conference (PSGC) has designated this area for low density residential purposes on the Interim Regional Development Plan. b. Local Improvement District (LID) Procedures The revised code of Washington Chapter 35.43 specifies that any city or town may order the whole or part of any local improvement and may levy and collect special assessments on property specifically benefited to pay all or any part of the expense. A local improvement may be ordered only by an ordinance of the city or town council as a result of a resolution or by the filing of a petition by the owners of property aggregating a majority of both the lineal•frontage and the area of the proposed LID. In the present case the LID is a result of a petition, which has already been submitted. The petitioners own 91% of the total area and 70% of the frontage. Next a city designated official reviews the sufficiency of the petition and other statutorily required information such as cost estimates. (See Appendix). Notice of intention to order an improvement will be published in two consecutive issues of a local newspaper. Notice will be also mailed to the affected property owners. After a thirty day period, if there are no objections, an ordinance creating the LID and ordering the improvement will be passed by a majority vote of the council. In this case, the ordinance forming the LID will stipulate that any area which joins at a later date will also pay according to the benefit received through a late comer's agreement. After the final design work is authorized, the council publishes a call for bids for the construction, analyzes the received bids and awards a contract. The interim costs of the proposed sewer and water facilities will be financed by bonds issued by the city. These bonds will be retired by payments from the final assessments. Upon completion of the project, the total cost is determined and final assessment roll is prepared and filed with the city clerk. For the purpose of ascertaining the amount to be assessed against each separate lot, or parcel of land, the LID will be divided into subdivisions or zones paralleling the street. There will be three 300 foot zones and a percentage of cost of the improvement will be distributed against each of these zones. Thus each property owner will be assessed a varying amount according to how much property is owned within each zone. Although other assessment methods may be utilized, -10- this procedure is deemed to most fairly reflect the benefit to the property assessed in the present case. A public hearing will be conducted in which objections and modifications to the final assessment will be considered. Notification of this hearing will be given in the same manner as previously described. An ordinance will then be adopted confirming and levying assessments as finally approved. c. Review and Permits In addition to the LID procedures described above, the following permits must be issued and the following review procedures be undertaken with regard to the proposed project: Building Permit. Review of State Department of Ecology Flood Control Zone Permit by City Public Works Director. - Permit from METRO to connect into the METRO System. - Permit to cross the Puget Sound Power and Light Easement. - Permit to cross under the State Highway. - notice of construction and application for approval in order for Puget Sound Air Pollution Control Agency to evaluate whether the proposed action will meet PSAPCA Regulation I. - Future extensions may require additional permits to cross road easements. 8. Public Participation Incorporated within the administrative procedures which comprise the proposed action are a number of public hearing requirements as previously described. The proposed action implements adopted City Policies, as embodied primarily in Council Resolutions, the Compre- hensive Plan, the Comprehensive Zoning Ordinance, and other provisions of the Municipal Code. Each of these has been subjected to public review during the normal course of adoption. Public participation has been an important part of the decision - making and policy adoption by other agencies having jurisdiction for planning and implementation of policies influencing development on a regional basis. As an example, the Puget Sound Governmental Conference, the regional planning agency, has invited citizen input in the formulation of the Interim Regional Development Plan. Also, an on -going study, the Sea -Tac Communities Plan, is being sponsored by King County and the Port of Seattle to develop land use policies and goals for communities within'the Sea -Tac area. A portion of Tukwila, including the proposed LID and its potential service area, lie within the northeast corner of Sea -Tac Communities Study Area. The Sea -Tac Communities Plan is divided into three six - month phases, the first of which has been completed. The first phase consisted of an inventory of biophysical and social conditions as well as a survey of community opinions. The second phase will entail data analysis, and the third will involve recommendations for land use. Citizen involvement and input is a primary factor in all phases of the Sea -Tac Communities Plan. B. EXISTING CONDITIONS 1. Natural Setting a. General Setting The proposed LID, located in northwestern Tukwila, is situated on the western border of the Duwamish River flood plain, which expresses itself topographically as a relatively narrow flat - floored valley limited by steep valley walls on the east and west. The proposed LID lies at the base of the western valley wall and displays a gradiation in natural characteristics, from the steep valley wall environment to the alluvial flood plain environmentsof the Duwamish Valley. The proposed LID encompasses approximately 20.6 acres of land, including dedicated rights- of -way and streets. An additional 26.3 acres within the City of Tukwila could potentially be served by the proposed sewer and water improvements. Over 21 acres within King County and /or the Val Vue Sewer District could also be affected by the proposed sewer and water systems. In order to assess the full impact of the proposed LID, the 68.6 acre area which could ultimately be served by the proposed sewer and water systems comprises the study area of this inventory. Most of the topographic, biologic, hydrologic, and microclimate conditions of the proposed LID and the study area have been extensively altered by prior human activity. b. Topography Most of the study area displays typical glacial ground moraine and terrace topography, consisting of gently undulating to rolling physiography, interrupted by steep valley walls and shallow poorly drained despressions. Low lying portions of the study area, adjacent to State Route 599, however, display typical alluvial flood plain topographic features. Almost all of this portion of the study area consists of flat very poorly drained peaty and mucky recent flood plain deposits affected by long periods of high water table conditions. The study area is bordered on the south and west by very steep valley wall slopes which are dissected by small streams and creeks draining the Riverton, Riverton Heights, and Foster neighborhoods. Relief on the low -lying portions of the study area is generally less than ten feet, varying between six and fifteen feet above mean sea level. The glacial terrace and ground moraine deposits, located between the alluvial deposits and the valley wall, slope gently from an elevation of approximately thirty to fifty feet to an elevation of fifteen to twenty feet. The high point of the study area, near its southern boundary, reaches an elevation of about 112 feet. The low point of the study area is about 4 feet above mean sea level. The proposed LID topography varies between six and eighty feet. Figure D displays the topography of the study area. TOPOGRAPHY Fre, 0 -14- NORTH 0 200 400 600 11.1.6111;e1122.=1111111EICIONI 1 acre c. Geology 1) Geologic History The Puget Sound Region was covered at least four times in the Pleistocene Epoch by great ice sheets which ultimately advanced to just south of Olympia, covering all of the Puget Lowland and San Juan Islands and lying high against the flanks of the Olympics and the Cascades. Each of these Quarternary glaciations included many major and minor retreats and readvances. After each major glaciation, the Puget Sound Area was free of ice for a time and fluvial (river-land) and lacustrine (lake -laid) sediments accumulated on the glacial deposits. _ The final glacial advance affecting the South Puget Sound Region, the Vashon Stade (stage) of the Fraser glaciation, occurred between 20,000 and 12,000 years ago. During most of this period over 3,000 feet of ice covered the study area. The effects of this glaciation have obscured most of the preglacial topography and record of older glacial events in the vicinity of the proposed LID. The Vashon Glacier leveled off old glacial deposits and rock outcrops filled valleys, and dammed and diverted streams. Glacial erosion deepended pre- existing river valleys and produced the Lake Washington and Lake Sammamish Basins. Puget Sound, near the proposed LID, was deepened to as much as 1,000 feet below the present sea level. Where the ground was not excavated by the overriding ice, it was shaped. Most of the elongate hills of the Puget Sound Area owe their form to glacial shaping. The preliminary deposit resulting from the Vashon Glacier in the Puget Sound Area is Vashon till. Vashon till con- sists primarily of basal till, a deposit of various -sized stones, in a matrix of sand, silt, and clay, which were overridden by the advancing glacier and compacted by the immense weight of the ice, resulting in a concrete -like material, frequently referred to as hardpan. Typically, a thin deposit of loose, unsorted, uncompacted sand and gravel, known as ablation till was deposited over the basal till. Ablation till was derived from the sediment load in and on the ice as it ablated or melted, and is rarely over 40 inches thick. Till of the Vashon Age is the most wide spread geologic unit in the Puget Sound Region, forming continuous sheets over much of the area, broken only by subsequent stream erosion. In much of the vicinity of the proposed LID, the thickness of Vashon till deposits ranges between five and fifty feet. Much of the study is directly underlain by Vashon till. As the Vashon Glacier retreated north, ice - marginal and north - flowing rivers were dammed, as they were during the glacier's advance, and lakes were created. Silty glacial sediments were deposited in the Green and Duwamish River Valleys during these periods. Outwash, deposited by the streams and rivers originating from the melting glacier or overflow channels of the ice - dammed lakes, forms the remaining major deposit related to the Vashon Glacier. Consisting primarily of cobbles, stones, gravel, and sand, outwash was deposited in a stratified manner, due to its fluvial origin. As the ice continued to ablate or melt, retreating north- ward, the Strait of Juan de Fuca became ice -free and the • ocean invaded the Duwamish River Valley. In the 10,000 to 15,000 years since the glacial ice left, this embayment slowly filled alluvium deposited by the flood waters of the White, Green, Cedar, Black, and Duwamish Rivers. At first, the Green And Cedar Rivers built large fans into the embayment, which remained until about 5,000 years ago when the Osceola mudflow came down the White River Valley from Mount Rainier and forced the White River to flow into the Green and Duwamish River Valleys rather than into the South Prairie Creek and Puyallup River Valleys. Until 1906, when its entire flow was 'diverted south into the Puyallup River Valley during a flood, the White River was the predominant source of the sediments in the Green and Duwamish River Valleys, covering the older deposits and filling the valleys to nearly their present level. The Black and Cedar Rivers, which had flowed into the White and Duwamish Rivers a few miles upstream of the proposed LID, were diverted into Lake Washington in 1917 when the lake level was lowered as a consequence of the Lake Washington Ship Canal project. Since this time, only a thin layer of alluvium has been deposited in the lower Green and Duwamish River Valley flood plain by the Green and Duwamish Rivers. Nearly all of the alluvial material underlying the low - lying portions of the proposed LID and the study area can be assumed to be White River alluvium, overlain by a vari- able thickness of White and Duwamish River flood plain deposits. The alluvium underlying the study area is probably about fifty to one hundred feet thick, below which dense weathered basalt bedrock occurs. Additional post - glacial deposits in the study area and study area vicinity include peat and mass - wasting debris. The poorly drained shallow alluvial deposits of the study area probably contain extensive layers of peat and organic material. Discussions with soils engineers and other pro- fessionals familiar with the study area indicate that mixed peat and silt deposits to depths of over thirty feet can be expected throughout the low lying alluvial portion of the study area. Data from shallow (12') test pits near the existing warehouse south of South 134th Street within the proposed LID supports this expectation: Dark brown silty peat between 1 -2 and 4 -5 feet. Organic silt with peat between 4 -5 and 7 feet. Blue gray sandy silt with gravel between 7 and 9 -10 feet. Gray organic silty sand with cobbles between 9 -10 and 12 feet. The geologic units comprising the study area and its vicinity are displayed by Figure E. Their engineering properties and characteristics affecting land use planning decisions are described by Table 1. 2) Soils The soils of the proposed LID and its potential service area reflect their alluvial and glacial heritage. Approximately two-thirds of the study area is comprised of alderwood gravelly sand loam soils, the most common glacial till soil of the Puget Sound Area. Silty alluvial soils, mucks, and peat comprise the remainder of the study area. According to the 1952 Soil Survey of King County, Washington, Puget silty clay loam, Woodinville silt loam, Bellingham silty clay, and carbondale muck soil types make up the alluvial and peaty soils of the study area. The rectified 1971 Soil Survey of the King County Area describes the alluvial and peaty soils of the study area as Puyallup fine sandy loam, Puget silty clay loam, and Tukwila muck. The 1952 Soil Survey also notes a small area of Kitsap silt loam, hilly, along the southeastern boundary of the study area. This area is not described as Kitsap soil by the more recent soil survey. Field investigations conducted during this assessment found elements of both soils surveys to be correct, resulting in the Soils Map shown by Figure F. SURFICIAL GEOLOGY heurc E 7\ tape NO RTH - CHART I SUITABILITY FOR NON- PRODUCTIVE USES - ENGINEERING PROPERTIES - Soil Type Susceptibility Shearing Load Shrink Compressi- Resistance Resistance Compacted Corrosive Effect to frost Strength Carrying Swell bility To Sheet To Bank Permeability of soil on: action Capacity Potential Erosion Erosion (stability) Uncoated Concrete - Steel Alderwood Slight gravelly to sandy loam high High - Moderate Low Slight Low to moderate High Semi Mod. Mod. pervious to impervious Silty High Very low Mod. to High Moderate Low to Low to Semi- Very Mod. clay to low to moderate moderate pervious to high mod. very high impervious Muck High Very low Very High to Very high Low Very low Cannot be Very High low very high compacted high 1 Cathcart Mod. to Low to Mod. Low Very slightLow Low to Semi- Mod. Mod. gravelly high high to moderate high pervious to sandy loam moderate impervious Ki tsap silt loam Very high Very low Mod. to mod. Mod. to Moderate Low to Low to Semi- high to very high moderate pervious to high impervious Moderate High Puget High to silty clay very high loam Very low Low Mod. to Moderate Low high to very high Low Semi- High to High pervious to very high impervious Puyallup Slight fine sandy loam Low to high High Low to Very Low moderate slight to moderate Low Semi- Low Moderate pervious to impervious Peaty Mod. Very low Low to High Low to Moderate Low Impervious High High silt loam mod. moderate SUITABILITY FOR NON- PRODUCTIVE USES (CONTINUED) Suitability as a source of: Limitations for: Soil Type Topsoil Sand Gravel Roadfill Homesites Heavy Septic Passive Small Farms Bldg. Tank Uses and Gardens Sites Filter Areas Fields (picnic areas, etc.) Alderwood Fair Good Very Good Mod. (Industrial) None to Slight to gravelly to poor to to None to Very slight moderate sandy poor not suit- slight severe loam (6 -15 %) able Alderwood Fair Good Very Fair Severe None to Very Moderate Severe . gravelly to poor to to moderate severe sandy poor not suit- good loam (15.30 %) able No Silty Fair Not Not suit- Very Very Mod. to Very Severe to ' clay to suit- able suitable severe very severe very good able severe severe Severe Muck Good Not Not suit- Not Very Mod. to Very Severe to suit- able suitable severe very severe very severe able severe Moderate Cathcart Fair Poor Not suit — Good Severe None to Severe to Severe to Severe gravelly able moderate very very severe sandy loam severe Kitsap Good Not Not suit- Poor Very Severe Very Severe Very silt loam suit- able severe to very severe severe able severe Puget Good Not Not suit- Very poor Very Severe Very Severe Moderate silty clay suit- able to not severe to very severe loam able suitable severe SUITABILITY FOR NON - PRODUCTIVE USES (CONTINUED) Suitable as a source of: Limitations for: Soil Type Topsoil Sand Gravel Roadfill Homesites Heavy Septic Passive Small Farms Bldg. Tank Uses and Gardens Sites Filter Areas Fields (picnic areas, etc.) Puyallup Fair fine sandy loam Fair Not Good Very Mod to Severe to None to suitable severe very very moderate severe severe Slight Peaty Fair Not Not Not Severe to Mod. to Very Moderate silt suit- suitable suitable very very severe . to loam able severe severe severe Severe VI 11111111 =114-11.1114.6) SOILS fire r Alh 0 200 400 600 -22- The alderwood Gravelly Sandy Loam found within the study area consists of moderately well drained to poorly drained gravelly loam, gravelly sandy loam, sandy loam, and silt loam surface and subsoils overlying compact, impervious basal till deposits at depths of twenty to forty inches. Water which percolates through the rather loose subsoils flows along the surface of the basal till and ponds up in areas with little or no slope. Though surface drainage is usually fairly good, yellow and brown mottles, which occur in the few inches immediately above the impervious layer, indicate that subsurface drainage is restricted. Water, in general, is removed from these soils somewhat slowly, so the profile remains wet for a significant part of the year. Alderwood soils have a high shearing strength and load bearing capacity, with a small shrink-swell capacity. Puget silty clay loam consists of recently deposited deep poorly drained fine - textured alluvium. Formed under con- ditions of ponded or stagnated drainage, it appears to contain a great deal of glacial rock flour and fine glacial sediments. Many prominent mottles occur in the upper portion of the profile, which becomes very blue-gray below 30 to 35 inches, indicating the presence of a high water table for much of the year. Where artificial drainage is provided, Puget Silty Clay Loam has proved to be a quite productive soil. It is often used for oats, wheat, hay, forage crops, clover, potatoes, vegetable seed, bramble berries, or, as within the study area, strawberries and truck crops. The silty clay of the study area is quite similar to the Puget Silty Clay Loam described above, except for the presence of a heavy- textured impervious substratum of glacial origin. Water ponds up on this material, creating a cold wet soil environment and slowing decomposition and bacterial action. Organic matter has accumulated throughout the surface layers of this silty soil unit. Clay loam and clay subsoils occur below 20 inches. Yellow and reddish brown mottles occur below 8 inches, indicating the occurrence of a high water table. If moisture conditions were controlled, this soil would probably be well adapted to growing truck crops, hay, pasture, and oats. The muck found within the study area is highly organic and woody in nature, consisting of a well decomposed woody organic surface layer, underlain by very black to very dark brown muck to sixty inches or more. Recognizable woody and fibrous material in various stages of decomposition occurs throughout the profile. Mapped as Carbondale and Tukwila Muck by The Soil Conservation Service, it can be assumed that the muck deposits are quite deep (over thirty feet) in - �3- this soil type. Saturated in winter and early spring, this muck is very poorly drained. Surface runoff is ponded. This soil type is successfully utilized for pasture within the study area. The peaty silt loam of the proposed LID and the study area is quite similar to Woodinville soils. These are poorly drained silty clay loam alluvial soils, highly mottled below 12 inches with iron stains, which contain layers of peaty material thoughout the profile. The subsoil is stratified silty clay loam, silty clay, and clay. Surface and subsoil drainage is quite poorly developed, and a high water table is maintained throughout the year. Subject to frequent ponding, they can be successfully used for hay and pasture purposes if drained. All of the alluvial and peaty soils of the study area exhibit the typical characteristics of alluvial bottomland soils of the region. All, are subject to ponding during a three to eight month period of the year from October to May. Drainage problems are compounded by the very low to moderately low intake rates found in these soils. These rates, which express infiltration and percolation rates, range from an average of 0.3 inches per hour to an average of 0.47 inches per hour. This places severe limitations on the use of septic tanks in,particular, and on urban development without sanitary sewers in general. Severe limitations are also generally placed upon urban development of these soils due to their low load bearing capacities. Extra construction costs or damage to buildings or roads due to settling sometimes results from development on these soils. Another characteristic of .these soils is the aquifer recharge process they participate in. Though these soils have low intake rates, most overlie underground water- bearing strata. Consequently, they are moderately important as an aquifer recharge medium. Due to the very flat topography, loamy textures, good tilth and deep profiles with high water holding capacities, all of the low lying alluvial and peaty soils of the study area are classified as Class II (primary agricultural soils, with occasional damaging overflow or other associated hazards) or Class III (primary agricultural soils, with greater limitations for sustained production of commonly cultivated crops than Class II) soils by The Soil Conservation Service. Primary agricultural soils are a finite regional resource; as they are developed for non-agricultural purposes, the amount of land available and inherently suitable for crops decreases. The Alderwood soils of the study area are fairly well suited for developmental purposes. The primary problem associated with their intensive use is erosion control. The aforementioned ponding (in seeps on slopes or in small depressions) situation which often occurs during the wet season may, however, flood basements. The drainage problems of alderwood soils seriously affect the proper functioning of septic tank drainage fields. Most of the septic tank overflow cases in the vicinity of the study area (in the upper part of the watershed draining into the study area) occur in Alderwood soils. The physical properties of the soils found within the study area are described by Table 2. As the soils of the study area vary in their characteristics, their inherent suit - abilities for various land uses also vary greatly. Table 2 describes the suitability of the study area's soils for productive uses. The suitability of the study area's soils . for non - productive uses is described by Table 3. d. Hydrology The proposed LID and its potential and ultimate service areas comprise the lower portion of a small (approximately 700 acre) drainage basin encompassing much of the Riverton, Riverton Heights, and Foster neighborhoods. The four distinct small creeks which drain this area merge within the study area and enter the Duwamish River as a single stream approximately 300 feet upstream of the Allentown Bridge (see Figure H). Within the proposed LID most of the creeks and streams flow through artificial drainage channels, culverts, and roadside ditches. In those portions of the study area outside and upstream of the proposed LID, most of the creeks and streams flow though relatively natural channels. Downstream of the proposed LID, roadside ditches,culverts, and drainage channels transport the flowing surface water. Also designated on Figure G are locations where septic tank overflows have been officially reported to the Health Department within the last ten years. Actual incidents of septic tank overflows are probably much higher. Drainage from those areas which have a history of septic tank overflows eventually enters the streams which pass through the subject site. To create large filled areas within the proposed LID, the under- lying soils have been covered with six to ten feet of clayey, sandy, and silty sand. The fill is fairly compact when dry, except for those areas along the remnants of stream beds. When wet, infiltration of surface moisture creates a soft "quick" textured material. PHYSICAL PROPERTIES OF THE SUBJECT SITE'S SOIL SOIL TYPE SURFACE SOIL SUBSOIL SUBSTRATA Texture Depth to Intake And /or Permea- Seasonal Depth to Rate Permeability Parent bility High Water Impervious Texture (In /hr.) Texture r (In /hr.) Material (In /hr.) Table Layer Alderwood Loam, silt Very friable gravelly loam, gravelly .2 - .75 gravelly, sandy loam sandy loam, sandy loam gravelly loam . 8 - 2.5 Firm, cemented sandy and gravelly basal till Surface .01 - .2 to 30" + 34 - 40" Silty Clay Silty clay loam, clay loam, clay, sily, loam . 1 - .3 Firm, sticky .05 - .2 silty clay loam, silty clay, or clay Firm, sticky Less than Surface Variable clay and sandy .05 to (usually clay 1' + over 60 ") Muck Muck .2 - .4 .Fibrous .05 - 2.5 Sedimentary Less Surface Over woody peat peat, sand, than to 60" silt or clay. .05. 1' + ON Cathart Loam, gravelly .2 - .5 Hard .8 - 2.5 Hard sandy .05 - 2.5 30" - 60" Usually Gravelly loam, gravelly gritty loam; usually or bedrock 48 - 60" Sandy loam silt loam, loam sandstone at stony loam 4 feet + clay loam Ki tsap Silt Loam Silt loam, silty clay loam, loam, gravelly loam .2 - .5 Firm, hard, sticky, laminated silty loam and silty clay loam . 05 - .2 Very firm, Less hard, sticky than laminated .05. silt loam and fine sandy loam 18" - 36" Over 60" Puget Silty Silt loam, Clay Loam silty clay loam, clay loam, loam, silty clay, silty loam clay . 1 - .75 Firm, sticky .2 - .8 plastic silt loam, silty clay loam or clay (Lake sediments).05 - .2 Surface Firm, hard to 1" very sticky and plastic silty clay loam or clay Over 60" Page Two of Table Two PHYSICAL PROPERTIES OF THE SUBJECT SITE'S SOIL SOIL TYPE SURFACE SOIL SUBSOIL SUBSTRATA Texture Intake Rate (In /hr.) Texture Permeability (In /hr.) Texture Depth to And /or Permea- Seasonal Depth to Parent bility High Water Impervious Material (In /hr.) Table Layer Puyallup fine sandy loam Sandy loam fine sandy loam, silt loam, loam loamy fine sand. .2 - .75 Loose fine sandy loam, very fine sandy loam - 2.5 Loose fine 5.0 - 10.0 40" - 60" Over sandy loam 60" to fine sand Peaty Silt Loam Silt .2 - .4 Firm, slightly Less than Firm, Less than Surface. Over loam sticky and 0.05 slightly 0.05 to 1' + 60" plastic silty sticky and clay loam, plastic lilty clay and silty clay, clay. clay and peat. . _ _ - Soil Type TABLE 3 SUITABILITY FOR PRODUCTIVE USES S.C.S. Available Water Depth of Capability Water Holding Root Class Capacity Capacity Penetration (in /in) (inches) Representative potential crop yields per acre under average management practices without supplemental irrigation Grass & Legume Pasture Silage Small Broccoli Strawberries, or Alfalfa (AUM) (tons) Grains Peas, Pole Caneberries Hay (tons) (tons) Beans,Sweet (tons) Corn,etc. (tons) Alderwood IV gravelly sandy loam (6 -15 %) 0 - .11 3.3 - 6.o 20 - 36 1.75 - 5.0 4.25 - 5.4 ND NS 2 6 12 15.5 Alderwood VI 0 .11 3.3 - 6.0 20 - 36 1.5 - 2.5 3 - 6 NS ND NS NS gravelly sandy loam (15.30 %) Silty Clay III .2 - .24 5.5 - 6.5 12 - 30 2.5 - 5.0 6 - 12 7.0 -- 1.75 - 2 4 NS 15.5 2.4 CO Muck II .35 - .40 4.4 -12.0 12 - 36 3.0 - 8.0 8.25 - 10.0 - ND 2 - 6.5 NS 19.0 24.8 Cathcart IV 0 .11 6.0 -10.0 36 - 60 2.0 - 8.0 '4.75 - 6.0 - .6 NS 1.5 - 2.0 gravelly 19.0 24.8 sandy loam Kitsap V I Silt Loam .04 - 6 6.o - 7.0 20 - 40 ND 5 - 8 ND ND ND ND Puget II .2 - .24 Over 40 '- 60. 3.0 - 8.0 7 - 19 9.3 - 1.8 - 2.4 - 5 silty clay 8.5 24.8 2.4 8* loam Puyallup II fine sandy loam .o4 - .18 5.0 - 8.0 40 - 60 2.5 - 8.5* 7 - 9.3 - .5 - 3 - 8* 3.5 - 7.0* 20.0* 26.3* 1.0 Peaty III ND 5.0 - 8.0 12 - 30 2.5 - 4.5 6 - 7.75 - ND 3 4 NS silt 9.5 12.4 loam NS = Not suitable ND = No data * =. Highest potential yield of all Puget Sound area soils HYDROLOGY Fguz 4. NORTH 0 200 400 600 1 e. Water Quality 1) The Green River The Green River originates on the west slope of the Cascade Range and flows north and east about 60 miles to a point near the subject site at which the upper limit of tidal influence is noted. Downstream of this point the river is known as the Duwamish River. Therefore, an analysis of both the Duwamish River and the Green River pertain to the subject site. The Duwamish River estuary is an important industrial waterway and has been receiving industrial, municipal, and storm water wastes since the early 1900's. By the 1940's fisheries - resource agencies and commercial interests became concerned about the impact of degraded water quality on the rich aquatic life of the estuary. In 1958, in response to growing water quality problems throughout the Seattle Metropolitan Area, Seattle area residents voted to form the Municipality of Metropolitan Seattle (METRO). METRO is a federation of cities united to deal with waste water disposal and transportation service. The METRO Comprehensive Sewerage Plan includes an extensive network of sewer trunklines and several sewage treatment plants. The Renton treatment plant is located upstream on the Green - Duwamish River and discharges effluent to the river. The Green- Uuwamish River flows northerly past a location near the subject site where the stream draining the subject site empties. Raw and partially- treated wastes entering the Duwamish and Lower Green Rivers as well as wastes from manufacturing and food processing plants are being decreased as the network of sewer trunklines and treatment plants is completed, in accordance with METRO's Comprehesnive Plan. Since June 1965, the Renton treatment plant (RTP) has been discharging increasing amounts of treated effluent to the Duwamish River as new trunklines have been constructed and the treatment plant's service area has been enlarged. From 1963 to 1967 METRO and the U. S. Geological Survey conducted a cooperative study of water quality in the Lower Duwamish River in order to determine the chemical, physical, and ecological changes that take place in the estuary when raw or partially- treated wastes are replaced by treated effluent from the Renton treatment plant. This study was primarily concerned with the hydraulics of the estuary, the physical and chemical characteristics of the water (temperature, dissolved oxygen, and biochemical oxygen demand), and certain aspects of the ecology relating to the plankton communities. The findings of this early study have been substantiated by later studies performed by Dr. Eugene Welch at the University of Washington in 1967 and 1969, and by the RIBCO (the River Basin Coordinating Committee, a technical advisory committee to METRO) Water Quality Management Study Interim Report of October 1973. -30- Conclusions regarding the interpretations of past trends and data, as well as specific estimates of possible future impacts affectitng the Duwamish estuary and Green River will be available in-the near future as RIBCO completes its estuary studies. Prior to the introduction of the RTP effluent, conditions of low dissolved oxygen were recorded in the lower estuary in the late summer. The Green - Duwamish River still exper- iences such low dissolved oxygen conditions during the summer months. ,The initial study performed by the U.S.G.S. did not conclusively determine the impact of the RTP on dissolved owygen levels at the point of discharge. Although the most recent METRO six - month report analyzing data from October 1972 through March 1973 (the next six -month report should be completed soon) indicates an improving trend in dissolved oxygen levels are still a problem. Low dissolved oxygen in the Duwamish Estuary is attributable to oxygen consumption by benthos (bottom organisms) and algae as well as low temperatures due to shallow depths, low flows, and inadequate shading. According to METRO, a condition may be approached where oxygen levels will exceed the requirements for fish life on an annual basis. However, it appears to be highly unlikely that the present anadromous fish runs or annual aquatic ecosystem of the Duwamish will be affected by dissolved oxygen depressions, according to RIBCO biologists. By way of a general note, dissolved oxygen is a key para- meter in the Green- Duwamish River and in similar streams that have commercially and recreationally important fish populations. The respiratory processes of fish, shellfish, benthos, etc. are affected by changes in dissolved oxygen content. Thus fish migratory patterns may be affected when dissolved oxygen drops below critical levels. The Green River produces- hundreds of thousands of resident and non- resident fish annually. Most of the chinook runs are produced from fry or fingerlings released from the Washington State Department of Fisheries' hatchery. Much natural spawning of chinook and other species of salmon also occurs. The dissolved oxygen is depleted by the oxidation (degrad- ation) of natural as well as man -made materials and is replaced naturally by aeration at the air -water surface or by mixing with water having greater dissolved oxygen and /or by photosynthesis of aquatic plants. Since the degradation of the more common wastes requires their oxidation, the variation in dissolved oxygen is a significant indicator of the general amount and persistence of pollutants. The capacity of water to retain dissolved oxygen is also reduced with increasing temperatures. Upstream from the project site, the river may be loaded slightly beyond its natural B.O.D. (biological oxygen demand) as indicated by the fact that both the average dissolved oxygen values and the average B.O.D. values at -31- the Renton station are lower than at the Kent station. The RTP is designed for a B.O.D. treatment efficiency of 96 %, and average treatment efficiencies typically approach this figure. Thus the B.O.D. contribution of the RTP to the Duwamish River can be expected to be relatively small, and it is possible that the effluent has only a small direct effect on dissolved oxygen concentrations in the estuary. Temperatures for the river from the monitoring station 315 at Kent upstream to the RTP, station 3071, are lower than those which would indicate thermal pollution levels. The river responds to inputs of warmer water from the RTP as shown by several stations downstream. At station 3077, a small decrease occurs as a result of the Ranier Vista Treatment Plant effluent, then the influence of Elliott Bay seawater is registered. The addition of heat in surface runoff from the developed site will probably be less inten- sive than the effects of the RTP. Ammonia and phosphate concentrations in the Duwamish River Estuary increased significantly downstream from the Renton Treatment Plant outfall after introduction of the effluent in June 1965. The Renton Treatment Plant is only 16% efficient for ammonia and 3% efficient for phosphates. The concentrations of these nutrients are a least doubled as a result of the present input of treated effluent from the plant. According to METRO data, the Renton Treatment Plant is a quite significant source of nitrites and nitrates. The impact on aquatic life in the estuary attributable to this input of nutrients is, however, unknown at this time. Maximum concentrations of all nutrients in the Duwamish Estuary occur at low tide, partly because at this time there is a minimum of seawater dilution of the Renton Treatment Plant effluent and of other fresh water nutrient sources. High levels of nutrients are also recorded in the fall and winter, however, when light conditions are minimum, a severe algal bloom cannot be sustained. Nuisance blooms and eutrophication are well known problems that develop from increases in phytoplankton production frequently caused by nutrients in domestic waste water. However, the SCS Study indicates that in the case of the Duwamish River, nutrient concentrations do not control the occurrence of the blooms inasmuch as nitrogen and phosphorous compounds always are present in sufficient quantities for a bloom to exist. For example, previous data indicates that a bloom occurred prior to the installation of the Renton Treatment Plant. The chief factors controlling whether or not a phyto- plankton bloom will occur are favorable hydrological and climatic conditions. Nutrients from the Renton Treatment Plant may increase the biomass produced by the phytoplankton blooms, once the other favorable conditions are established. The dissolved oxygen of surface waters is increased by the photosynthetic process of the bloom, but the dissolved oxygen of the subsurface waters is decreased as the plants die and oxygen is consumed in decomposition processes. -3 2- Coliform concentrations in the Duwamish River exceed the median count established by the water quality standards, according to the last six-month METRO report. Although a good relationship between total and fecal coliform is not evident, the same general trend of increasing contamination in downstream locations is apparent in the fecal coliform count as well. The low counts recorded in the RTP effluent indicates little if any influence from the plant on this trend. See Table 4 for additional water quality data. Soluble trace metal concentrations for copper and lead (Table 5) are fractions of a part per billion in the estuary water. These data were obtained from the trace metal laboratory, University of Washington, Department of Oceanography, core sampling within the estuary. The fate of metals borne by the rivers is transferral to the sediments. The concentrations of lead and zinc at the surface of the cores and one meter deep in the cores (Table 7) are extremely high and demonstrate how effectively the transfer proceeds. The cores were obtained in June, 1973, and were analyzed by the Region Ten Environmental Protection Agency Laboratory. Since nearshore ocean sediments contain an average of 60,000 ppb lead and 150,000 ppb zinc, it appears that the Duwamish Estuary sediments have been greatly enriched by inputs from the river and from industrial sites around the estuary. Therefore, any contamination from the proposed LID upon'ultimate development such as auto exhaust borne lead, which'is introduced into the river, would be transferred downstream to the surface sediments and would comprise an undetectable increase in the already heavily loaded sediments.. 2) Water Quality Standards The stretch of the river contiguous to the subject site is classified as Class A (excellent) waters by the Washington Department of Ecology (DOE). Whether or not the river meets this classification, however, is dependent on an analysis of individual parameters occurring within the river and comparing them to DOE water quality standards. Water quality for Class A waters shall meet or exceed the following criteria: Total fecal organisms shall not exceed median value of 240 (fresh water) with less than 20% of samples exceedi-ng 1,000 when associated with any fecal source. Dissolved oxygen shall exceed 8.0 mg /1 for fresh water. Temperature shall not exceed 65 F. (18.3 C). PH shall be in the range of 6.5 -8.5. Turbidity shall not exceed 5 JTU over natural conditions. -33- • -_. WATER QUALITY KENT TO ELLIOTT BAY JUNE. 1973 COLIFORM COUNTS /100 ML MEDIAN DISSOLVED METRO PRESENT LAST LAST FECAL AMMONIA NITRATE PHOSPHOROUS TEMPERATURE OXYGEN CONDUCTIVITY STATION MONTH MONTH YEAR COUNT mg /1 mg /1. mg /1 C mg /1 umhos /cm2 301 45 55 870 22 306 6,400 3,300 2,900 120 .48 .50 .24 16.3 307 9,400 4,600 2,300 50 .11 .26 .09 12.8 3077 3,400 6,700 -- 20 21.25 1.28 4.80 17.0 -- 3106 1,400 2,500 790 42 .70 .50 .35 17.1 3107 1,200 980 560 20 .38 .49 .26 17.2 351 110 20 80 20 .02 5.20 16.8 25.0 151 3108 700 540 1,700 50 .18 .49 .20 17.2 3131 320 60 35 .25 .14 8.00 18.2 315 740 510 20 .15 .40 .14 17.4 -- No Data TABLE 4:. WATER QUALITY KENT TO ELLIOTT BAY JULY 1973 COLIFORM COUNTS /100 ML MEDIAN DISSOLVED METRO PRESENT LAST LAST FECAL AMMONIA NITRATE PHOSPHOROUS TEMPERATURE OXYGEN CONDUCTIVITY STATION MONTH MONTH YEAR COUNT mg /1 mg /1 mg /1 C mg /1 umhos /cm2 301 90. . 45 430 33 306 2,600 6,400 2,300 190 .31 .36 .25 15.7 307 5,700 9,400 3,400 180 .30 .36 .24 15.5 3077 800 3,400 53 25.32 .87 4.35 17.2 - 3106 6,800 1,400 2,000 510 .6o .40 .38 16.4, -- 3107 2,700 1,200 1,900 30 .20 .46 .23 16.6 351 510 110 20 20 12.25 .39 4.75 20.0 8.2 113 3108 1,600 700 86o 170 .05 .38 .13 15.9 3131* 240 320. 20 7.80 .52 • 9.00 00.9 315 1,000 740 640 88 .10 .24 .14 15.8 -- No Data * Discontinued TABLE 4- (Cont'd.) WATER QUALITY KENT TO ELLIOTT BAY AUGUST 1973 COLIFORM COUNTS /100 ML MEDIAN DISSOLVED METRO - PRESENT LAST LAST FECAL AMMONIA NITRATE PHOSPHOROUS TEMPERATURE OXYGEN CONDUCTIVITY STATION MONTH - MONTH YEAR COUNT mg /1 mg /1 mg /1 C mg /1 umhos /cm2 301 -- -- 306 16,000 2,600 4,500 580 .42 .48 .33 14.2 307 ` 17,000 5,700 - 2,800 400 .49 .64 .49 17.0 3077 380 800 20 15.00 .40 8.10 18.5 3106 2,600 6,800 1,700 20 .45 .58 .34 16.9 3107 8,800 2,700 2,600 37 .11 .52 .23 16.9 351 51 510 290 20 6.12 3.60 3.85 17.8 7.9 13J 3108 2,200 1,600 950 28 .13 .50 .1U 16.9 - 315 1,400 1,000 1,100 270 .13 .33 .14 15.2 -- No Data TABLE 4. (Cont'd.) WATER QUALITY KENT TO ELLIOTT BAY SEPT 1973 COLIFORM COUNTS /100 ML MEDIAN DISSOLVED METRO PRESENT LAST LAST FECAL AMMONIA NITRATE PHOSPHOROUS TEMPERATURE OXYGEN CONDUCTIVITY STATION MONTH MONTH YEAR COUNT mg /1 mg /1 mg /1 C mg /1 umhos /cm2 301 -- 306 10,000 16,000 6,600 260 .26 .88 .11 15.0 307 5,300 17,000 6,300 320 .14 .44 .29 12.8 3077 440 380 110 28.35 .20 8.10 20.0 3106 620 2,600 3,800 20 .80 .64 .36 15.8 3107 5,600 8',800 12,000 95 .23 .60 .36 15.8 351 - 44o 51 980 98 6.00 3.10 6.10 15.3 8.4 138 3108 5,700 2,200 2,900 100 .16 .52 .25 15.2 - 315 2,700 1,400 720 520 .14 .40 .17 13.5 -- No Data TABLE 4 (Cont'd.) TABLE 5 METALS CONCENTRATIONS IN DUWAMISH ESTUARY (ppb) Soluble Metals Depth Date Location (Meters) Cu Pb 9/13/72 West Waterway 0 0.15 0.16 15 0.15 0.40 6/01/71 West Waterway 8 0.4 17 0.4 9/13/72 East Waterway 0 0.4 0.44 15 0.07 0.13 6/01/72 East Waterway 3 0.4 8 1.9 13 0.5 Sediments (Total Acid Soluble) Core No. 12 11 10 16 Depth Location (Meters) . Pb Zn Duwamish Mouth 0 71,000 130,000 Duwamish Mouth 0 194,000 25,000 - 1 152,000 20,000 Duwamish Mouth 0 195,000 400,000 -1 18,000 69,000_ East Waterway 0 346,000 600,000 - 1 61,000 140,000 3) Subject Site Stream Water quality of the stream flowing through the area to be served by the proposed LID was sampled on November 21, 1973. Three locations were chosen for sampling in order to gain a dynamic perspective of water quality conditions as the stream enters -and leaves the site. Samples were taken at the following three locations: Station 1: Where the east fork of the stream passes under 136th,. approximately 100 yeards east of 136th & 49th Place South. Station 11: Where the middle fork of the stream intersects 42nd & Marginal Way. Station 111:, , Where the main fork of the stream passes through farm lands directly east of 42nd & South of the freeway.' a) Sample Methods: Sample methods and analysis were performed according to method specified in Standard Methods: 13th Edition; for the examination of water and waste water. Periphyton samples were analyzed according to methods specified in IBP Handbook No. 12, A Manual on Methods for Measuring Primary Production in Equatic Environ- ments. Coliform samples were tested and analyzed by the methods specified in Standard Methods for the exam- ination of Water and Wastewater, 13th Edition. Macroinvertebrates were collected with a serber sampler and the species analyzed were used in the calculations =for a diversity index. Results Water quality data for the stream flowing through the subject site is summarized in Table 6. A ph value of 7.7 was . obtained for Station 1, 6.4 for Station 11, and 8.4 for Station III. Station I and II are well within the limits set for surface water criteria for public waters, which states the ph must lie between 6.0 and 8.5. Station III with a ph of 8.4 is just within the limits for permissible water. Dissolved oxygen (DO) was measured as 9.0 micrograms per liter (mg /1) at Station 1, 10.25 mg /1 at Station 11 and 9.6 mg /1 at Station 111. These values indicate extremely good conditions for this parameter as should -39- be expected for a flowing stream of such character. Where this stream enters the Duwamish the DO on November 21, 1973, was 5.0 mg /liter (5.0 ppm). This means that the water in the stream had almost twice the amount of DO as the Duwamish River. Ammonia (NH3) was measured as 33.0 micrograms per liter (ug /1) at Station 1 and 173.6 ug /1 at Station 111. These values are high with respect to water criteria for Public Water Supplies. Permissible water must have less than 50.0 ug /liter. Station 111 does not meet these requirements. This is possible due to leachage from septic tanks but is most likely due to leachage from livestock - supporting acreage which adjoins the stream. The following concentrations of ammonia have been reported to be toxic or lethal to fish within the specified times: 70.0 ug /liter 390 minutes Rainbow Trout 120.0 ug /liter 193 minutes Squalius cephalus Thus Station 111 might be toxic to fish on the day sampled. At the point where the stream enters the Duwamish River, the NH3 -N value of the Duwamish is 0.12 ug /liter. This indicates that the stream's NH3 -N values are almost 14 times greater than the Duwamish's. Organic nitrogen (NO3 -N) was measured as 2.10 mg/1 at Station 1 and 1.94 mg /1 at Station 111. The Duwamish, at the point of entry of the stream, has .40 mg /liter NO3 -N or about 1/5 the amount of NO3 -N as the stream, As with the NH3 -N, this is most likely due to leachage of organic wastes which enter the stream. Nitrates are the end product of aerobic stabilization of organic nitrogen, and as such they occur in polluted waters that have undergone self - purifaction or aerobic treatment process. Nitrates also occur in percolating fertilizer leaching from cesspools. Thus it may be assumed from these results that a great source of organic nitrogen exists which contributes large quantities of NO3 -N into the stream. Phosphates (Ortho PO4 -P) was measured as 116.82 ug /1 at Station 1, and 3147.04 ug /1 at Station 111. Biological Oxygen Demand (BOD) was measured as 1.8 mg /1 at Station 1,.2.3 mg /1 at Station 11, and 1.8 mg /1 at Station 111. -4o- TABLE 6 SUMMARY OF WATER QUALITY DATA FOR SELECTED LOCATIONS FOR SUBJECT SITE STREAM STATION Temperature C 9.0 PH 7.7 Dissolved Oxygen (D.0.) mg /1 9.0 Ammonia (NH3 -N) ugm /1 33.0 Organic Nitrogen (NO3 -N) mg /1 2.10 Phosphate (ORTHO PO4P) ug /1 16.82 Biological Oxygen Demand mg /1 1.8 Alkalinity (as CaCO3) mg /1 6.6 Silica mg /1 10.0 9.0 6.4 10.25 9.0 8.4 9.6 173.6 1.94 147.04 2.3 1.8 4.0 10.0 9.6 10.0 Specific Conductance 4.19 X 103 3.22 X 103 ' 5.9 -10.0 X 103 micro - ohms /cm2 Dissolved Solids mg /1 263.9 Turbidity Jackson Candle Units 202.8 351.7 -600.0 7.5 31.0 5.7 , Periphyton - Average algal biomass 4.42 ug chlorophyll per cubic um. Coliform - MPN = 4,600/100/m1 MPN = 11,000 /100 ml Although conclusions cannot be drawn from these BOD values at this time, the data may be useful if a comparative analysis is required at a later time. A comparative analysis could be useful to determine if organic materials are being fully oxidized into basic nutrients before entering the stream as a result of leachage from the adjacent land. Alkalinity (as CaCo3) was measured as 66.0 mg /1 at Station 1, 40.0 mg /1. at Station 11, and 96.0 mg /l•at Station 111. These values indicate a possible fluxation in ph. Alkalinity, a buffer system, usually ranges from 30 -500 mg /1 in most water systems. Silica was greater than 10-mg /1 at all three stations. Although these values are high, they are not uncommon. Specific conductance was measured as 4.19 X 103 micro - ohms/cm at Station 1, 3.22 X 10 micro- ohms /cm at Station 11, and 5.9. - 10.0 X 10 micro - ohms /cm at Station 111. These high values are probably due to rainfall during the sampling period. Dissolved solids were measured as 263.9 mg /1 at Station 1, 202.8 mg /1 at Station 11, and 351.7 mg /1 at Station . 111. It has been reported that among inland waters in the United States supporting a good fish fauna, about 5% have a dissolved solids concentration under 72 mg /1 about 50% under 169 /mg /1: This shows that this stream exceeds these limitis for a productive fish population. Turbidity was measured as 7.5 J.C.U. (Jackson Candle Units) at Station 1, 31.0 J.C.U. at Station 11, and 5.7 J.C.U. at Station 111. The high value recorded at Station 11 is probably due to nearby construction activities. The periphyton analysis indicates that the average algal biomass in this stream was 4.42 ug Chlo /cm2. Again, this data will be useful if a comparative analysis becomes necessary at a later date. According to the coliform Most Probably Number Test, Station 1. values were 4,600 coliforms per 100 ml (95% confidence limits .= 71024,000 per 100 ml) and Station 111 values were 11,000 coliforms per 100 ml (95% confidence limits = 1,500- 48,000 per ml). The number of coliforms at Station 111 exceeds the limit permissible by the Federal Water Pollution Control Administration. The water at Station 1, although within the permissible limits, far exceeds the Administration's desirable limits. -42- The high number of coliforms at Station III is probably due to leaching from the adjacent acreage housing livestock. At the point where the stream meets the Duwamish River, the Duwamish has only 700 coliforms per 100 ml. Stream Macroinvertebrates Macroinvertebrates were collected with a serber sampler (two samples were taken at Station I and 111). The following organisms were observed as'a result of sampling at the three stations: Station 1: Sample A 32 Mayflies (Baetidae) 14 Caddisflies (Hydropsychidae) 10 Stone flies (Nemouridae) 1 Scud (Gammaridae) 1 Snail (Physidae) 2 Fly Nymph (Chironomidae) Diversity Index 1.3252 Station 2: Sample A 3 Worms (01igochaete) Diversity Index 0.00 Diversity Index found by: _ -o H = ZN /No In N /No O Sample B 12 Mayflies (Baetidae) 7 Caddisflies (Hydropsychidae) 1 Snail (Physidae) 1 Snail (Planorbidae) Diversity Index .9718 Sample B Diversity Index 0.00 Where N equals the number in each species and No equals the total numbers of individuals present. Example: Sample 1B H = (12/21 ln 12/21) +(7/21 ln 7/21) +(1/21 lnl /21)+ /21 lnl /21] = .9718. -43- Diversities of less than 2 are considered to be an indi- cation of deteriorated conditions in the stream. This could be attributable to many factors which can't be established on the basis of this study,of the Benthic organisms present. At any rate, it is certain that the streams have deteriorated. The extremely low diversity found at stations 2 and 3 are more attributable to poor substrate than to poor water quality. The small pebble size rocks on the bottom are susceptable to bed movement and thus are unsuitable sites as habitats for many of the organisms. However, since there were no large size rocks in the area to obtain a sample from, it wasn't possible to determine what could grow there. Index for determination of pollutants: Waste Types: H Heavy polluted Moderately Polluted Good"Condition H above 5.0 is uncommon Table above by: Wilhm & Dorris Bio Science Volume 18 1968 <1 1.0 - 3.0 3.0 - 5.0 f. Biology 1) General Conditions Even though a substantial- portion of the study area has been significantly altered by human activity, the study area does retain some remnants of productive biological systems. The low density residential areas, small farms and gardens, vacant overgrown areas, fencelines, and heavily vegetated steep slopes provide valuable habitats for small mammals, birds, amphibians, and reptiles. The bulk of the area within the proposed LID and study area, particularly the developed and filled areas, however, provides little or no valuable terrestrial habitat. Botany r The plant associations of the study area and study area vicinity are described by Figure H. These plant assoc- ,iations reflect the intensive alteration of the study area's natural environment by prior human activity. Only a small portion of the study area, containing - mixed subclimax forests on very steep slopes, can be considered to be relatively "natural" in character. Most of the remainder of the study area is dominated by introduced and /or orn- amental plant species comprising controlled, early- succes- sional, or mid - successional plant associations. Specifically, the areas delimited as early- successional plant associations are dominated by thistles, plantain, clover, other herbaceous plants, and various grasses. Along waterways, horsetail and stinging nettle dominate. Occupying roadside areas,and recently disturbed sites, this association generally lasts for four to five years if undisturbed. Annual species dominate until the third or fourth of this "weed stage" of plant succession, at which time the perennial species invade and dominate. The mid - successional portions of the study area are dom- inated by various willows, red alder, birch, cottonwood, and douglasfir saplings, cream bush ocean- spray, Pacific ninebark, redosier dogwood, high -bush cranberry, bracken fern, Himalayan blackberry, Scot's broom, and common nightshade. This "shrub stage" plant association typically remains in existence until overtopped by tree saplings. Within many portions of the study area presently dominated by this plant association, tree saplings are successful invaders. If plant succession were to continue undisturbed, it is likely that within ten years much of the area presently characterized by a mid - successional plant association would take on the character of a forest. -45- )";/7i/Wi / // // PLANT ASSOCIATIONS rtre, 0 200 400 600 — 46 — The mixed subclimax forest areas of the study area are dominated by douglas -fir, red alder, big -leaf maple, and scouler willow trees. The understory, which varies greatly throughout the study area in this plant association, is dominated by willows, vine maple, Himalayan blackberry, sword -fern, and a variety of grasses. The present condition of this plant association would probably continue for ten to forty years, or more, if undisturbed. No saplings of the probable "climax" species, Western hemlock and Western red - cedar, were found invading the subclimax forest of the study area. No seed source of these species was noted, though some scattered mature Western red -cedar trees do exist throughout the study area. Agricultural, pasture, and open areas contain "controlled" plant associations which vary greatly in character and complexity. Included in this plant association are large expanses of lawn and pastureland, as well as areas dominated by strawberries, cane berries, corn, pumpkin, squash, cabbage, and other vegetable crops. Native and introduced grasses, rushes, and herbaceous and perennial weeds dominated the "uncontrolled" flora. Similar to the agricultural, pasture, and open areas plant association, the areas mapped as orchard plant associations represent "controlled" or previously "controlled" situations. Dominated by cultivated apple trees, these areas generally contain dense shrub or tall grass understor1es. The developed and urban areas of the study area contain plant associations dominated by a great variety of orna- mental plant species. A complete range of plants comprises this plant association, including tall ornamental trees, evergreen and deciduous shrubs, perennials, and annuals. Areas delineated as barren are dominated by bare earth and exposed soil. Vegetation, if any, usually consists of weeds and hardy herbaceous species, grasses, and various rushes. Much of the proposed LID consists of this plant association. A complete listing of the most common plant species found within the study area is provided by Table . No rare, uncommon, or unusual plant species were noted, though the frequent occurrence of high -bush cranberry throughout the study area can be considered rather unusual. This plant, which indicates persistent high water table or very moist conditions, is typically found as scattered individuals in moist woods. Perhaps fifty to one hundred individuals of this seldom seen species occur within the proposed LID and the study area. -47- In addition to the plants listed by Table 7, numerous unknown mushroom species are found throughout the study area. Aquatic plants, not noted by Table 7, including duckweed, pondweed, crowfoots, water - ferns, and loosestrife varieties have become established in many of the drainage ditches, channels, and streams of the study area. TABLE 7 PLANT SPECIES FOUND IN THE PROPOSED LID AND THE STUDY AREA TREES AND WOODY SHRUBS (OVER COMMON NAME o* Yew var. o Lawson Cypress var. o* Hinoki Cypress var. o* Chinese Juniper var. o* Savin Juniper var. o* Oriental Arborvitae # Western Red -cedar o* Deodar Cedar o* Colorado Blue Spruce # Shore Pine o* Austrian Pine o* Scot's Pine • Douglas -Fir #* Lombardy Poplar #. Black Cottonwood #. Pacific Willow # Piper's Willow #. Scouler Willow #*. Weeping Willow #. Red Alder # *. Birch var. Hazelnut # Redflowering Currant • Hawthorn var. # Creambush Ocean -spray # Pacific Ninebark o* English Laurel o* Portuguese Laurel o* • Flowering Cherry o* Cultivated Peach - *. Cultivated Apple o* Cultivated Pear English Holly # Western Crabapple • Common Horsechestnut Big -leaf Maple Vine Maple o* Flowering Dogwood # Red - osier Dogwood • Privet var. o* Lilac var. Blue Elderberry Red Elderberry #. High -bush Cranberry -49- HIGH) SCIENTIFIC NAME Taxus spp. Chamaecyparis lawsoniana var. Chamaecyparis obtusa var. Juniperus chinensis var. Juniperus sabina var. Thuja orientalis var. Thuja plicata Cedrus deodara Picea pungens kosteriana Pinus contorta var. Pinus nigra Pinus sylvestris Pseduotsuga menziesii Populus nigra italica Populus trichocarpa Salix lasiandra Salix piperi Salix scouleriana Salix babylonica Alnus rubra Betu'la spp. Corylus cornuta var. Ribes sanguineum Crataegus spp. Holodiscus discolor Physocarpus capitatus Prunus laurocerasus Prunus lusitanica Prunus spp. Prunus persica var. Pyrus malus var. Pyrus communis var. Ilex aquifolium var. Pyrus fusca Aesculus hippocastanum Acer macrophyllum Acer circinatum Cornus florida Cornus stolonifera Ligustrum spp. Syringa sp. Sambucus cerulea Sambucus racemosa var. Viburnum opulus 0* o -• o* 0* o* 0* 0* 0* • SHRUBS AND FORBS .(TO 6' HIGH) COMMON NAME Bracken -fern Mackenzie Willow. Box Japanese Flowering Quince Cultivated Rose var. Wild Rose var. Himalayan Blackberry Cultivated Raspberry Red Raspberry Scot's Broom Cultivated Grape Rhododendron var. Forsythia Japanese Laurel Common Snowberry Viburnum sp. Common Sunflower SCIENTIFIC NAME Pteridium aquilinum Salix rigida var. Buxus sempervirens Chaenomeles japonica Rosa spp. Rosa spp. Rubus discolor Rubus idaeus var. Rubus idaeus Cytisus scoparius Vitis vinifera var. Rhododendron spp. Forsythia suspensa Aucuba japonica var. Symphoricarpos albus Viburnum sp. Helianthus annuus var. GROUNDCOVERS, VINES,AND HERBACEOUS PLANTS #.., Common Horsetail #. Water Horsetail Lady -fern Sword -fern Stinging Nettle Sourdock Chickweed Creeping Buttercup False Bugbane Strawberry Pacific Blackberry • Wild Sweetpea • White Clover • Red Clover • Ivy • Field Morning -glory Mullein #* Teasel Common Plantain English Plantain Field Mint *. Common Nightshade # Wild Cucumber Bur Ragweed Pearly - everlasting Chamomile var. Common Burdock Canadian Thistle Common Thistle Indian Thistle * -50- Equisetum fluviatile Equisetum arvense Athyrium filix- femina. Polystichum munitum Urtica dioica var. Rumex crispus Cerastium spp. Ranunculus repens Trautvetteria carolinensis Fragaria sp. Rubus ursinus Lathyrus sp. Trifolium repens Trifolium pratense Hedera, sp. Convolvulus arvensis Verbascum thapsus Dipsacus sylvestris Plantago major Plantago lanceolata Mentha arvensis Solanum dulcamara Echinocystis lobata Ambrosia acanthicarpa Anaphalis margaritacea Anthemis sp. Arctium minus Cirsium arvense Cirsium vulgare Cirsium edule GROUNDCOVERS, VINES, AND HERBACEOUS PLANTS (Continued) COMMON NAME Field Milk - thistle Common Tansy Common Dandelion Hairy Cats -ear Rush var. Ovoid Spike -rush Grass var. SCIENTIFIC NAME Sonchus arvensis Tanacetum vulgare Taraxacum officinale Hypochaeris radicata Juncus spp. Eleocharis ovata Gramineae spp. o Found only as ornamental within study area. # Indicates seasonal high water table or moist conditions. Common species throughout the study area. Introduced species. 3) Terrestrial Wildlife The proposed LID and study area, while not a particularly unique or significant habitat, probably does provide food, cover, and /or nesting, resting, or roosting sites for a number of mammal, bird, reptile, and amphibian species. The dense cover and /or readily available food supply associated with the early and mid - successional plant associations; mixed subclimax forest areas; agricultural, pasture, and open areas; orchard areas; as well as many older ornamental plantings, attracts and supports a fairly sizable animal populations. Table 8 lists the wildlife species observed within the proposed LID and the study area during an inventory conducted for the purposes of this study. Table 9 details the field observations and conditions under which the inventories were conducted. By predation, domestic animal species probably maintain the terrestrial wildlife at levels below the capability of the study area's available habitats. The narrow bands of riparian shrubbery and woodland commun- ities along the stream courses and drainage channels of the study area probably act as natural green belts and migratory routes for many animal species, allowing them to exist throughout the partially urbanized situation of the study area. If the study area develops into a more urban environment, the existing animal population utilizing the study area may be trapped in pockets of open space and dense vegetation. Though landscaping may replace some of the habitats eliminated by the study area's development, these plantings generally cannot support wildlife populations as the original plant associations did. Typically, only pest species can thrive in disrupted ecosystems of developed areas. -5 2- COMMON NAME Domestic Geese Domestic Chicken Ruffed Grouse Ring- necked Pheasant Common Snipe Glaucous - winged Gull Rock Dove Red - shafted Flicker Steller's Jay Common Crow Black - capped Chickadee Common Bushtit Robin Starling House Sparrow House Finch Pine Siskin American Goldfinch Rufous -sided Towhee Oregon Junco Savannah Sparrow Fox Sparrow Song Sparrow Moles Unknown Mice Domestic Dog Domestic Cat Domestic Horse Domestic Cattle TABLE 8 TERRESTRIAL WILDLIFE KNOWN TO UTILIZE THE PROPOSED LID AND THE STUDY AREA BIRDS SCIENTIFIC NAME Anser spp. Gallus spp. Bonasa umbellus Phasianus colchicus Capella gal1inago Larus glaucescens Columba livia Colaptes cafer Cyanocitta stelleri Corvus brachyrhynchos Parus atricapillus Psaltriparus minimus Turdus migratorius Sturnus vulgaris Passer domesticus Carpodacus mexicanus Spinus pinus Spinus tristis Pipilo erythrophthalmus Junco oreganus Passerculus sandwichenis Passerella iliaca Melospiza melodia MAMMALS Scapanus sp. Family Cricetidae Canis spp. Felis spp. Family Equidae Family Bovidae OTHER SEASONALITY R R R R R, M R (W) R R R, M R R R R, M R, M R R, M M R (S) , M R, M R (W) R (S) , M R (W) , M R R R R R R R Frogs Order Salientia R R = RESIDENT M = MIGRANT W = WINTER S = SUMMER DATE: TEMPERATURE: TIME: CONDITIONS: AREA SURVEYED: COMMON NAME Ruffed Grouse TABLE .9 TERRESTRIAL WILDLIFE FIELD OBSERVATIONS 3 OCTOBER 73 50° F 10:30 - 11:45 A.M. (1,4 Hours) COOL, CLEAR, CALM 15± ACRES (THE PROPOSED LID) Ring- necked Pheasant Red - shafted Flicker Steller's Jay Common Crow Black - capped Chickadee Robin House Finch Pine Siskin American Goldfinch Savannah Sparrow Fox Sparrow Song Sparrow Domestic Dog Frogs BIRDS NUMBER SEEN OR ABUNDANCE 3 1 1 3 3 16 6 4 2 4 4 MAMMALS 3 LOCATION Western fenceline Western fenceline, and brushpiles. Throughout brushy portions of site. Tree grove in ravine. Tree grove in ravine. Shrubby areas, throughout site. Tree grove in ravine, western fenceline. Creek bottom and ravine. Creek bottom. Throughout brushy portions of site. Creek bottom. Western fenceline. Shrubby areas throughout site, brushpiles. Home near center of LID. OTHER Common Western fenceline and creek bottom. -54- DATE: TEMPERATURE: TIME: CONDITIONS: FIELD OBSERVATIONS (Continued) 15 NOVEMBER 73 40°F. 11:00 A.M. - 12:00 NOON (1 HOUR) COLD, OVERCAST/CALM, LIGHT TO HEAVY RAIN AREA SURVEYED: 30± ACRES (THE PROPOSED LID AND POTENTIAL TUKWILA SERVICE AREA), COMMON NAME Domestic Geese Domestic Chicken 'Common Snipe Glaucous - winged Gull Unknown Gull Rock Dove Black- capped Chickadee Common Bushtit Robin Starling House Sparrow House Finch Pine Siskin Oregon Junco Song Sparrow Domestic Cat Domestic Cattle Frogs BIRDS NUMBER SEEN OR ABUNDANCE .LOCATION 6 Farm. 4 Farm. 1 Creek bottom in LID fill. 3 Farm and farm vicinity. 3 Overhead 1 Near farm. 2 Brushy areas. 13 Brushy areas. 4 Throughout area. 2 Throughout area. 5 Farm and residential areas. 4 Throughout area. 34+ Throughout area. 1.3 Throughout area. 6 Brushy areas. MAMMALS 1 2 OTHER Common -55- Near farm. Farm. Near ponded water.- DATE: TEMPERATURE: TIME: CONDITIONS: FIELD OBSERVATIONS (Continued) 15 NOVEMBER 73 40° F. 2:15 - 4:15 P.M. (2 HOURS) COLD, OVERCAST, CALM, LIGHT TO HEAVY RAIN AREA - SURVEYED: 60± ACRES (THE STUDY AREA) METHOD: AUTO SURVEY, PRIMARILY COMMON NAME Ring- necked Pheasant Unknown Gull Red - shafted Flicker Black- capped Chickadee Robin Starling House Sparrow Pine Siskin Oregon Junco Song Sparrow Unknown Sparrow Moles Domestic Horse Domestic Cattle Frogs ,BIRDS NUMBER. SEEN OR ABUNDANCE 1, 3 2 4 27 22 7 30+ 11 5 5 MAMMALS Common 2 2 OTHER Common -56- LOCATION Farm. Overhead. Near 48th Avenue. Brushy areas. Throughout area. Near 48th Avenue Residential areas. Throughout area. Throughout area. Brushy areas. Ravines. Open Areas. Near South 136th. Farm. Throughout site (Except disturbed and filled areas). • FIELD OBSERVATIONS (Continued) DATE: 16 NOVEMBER 73 TEMPERATURE: 40° F. TIME: 3:45 - 4:30 P.M. (3/4 Hour) CONDITIONS: COLD, CLOUDY, WINDY AREA SURVEYED: 60± ACRES (THE STUDY AREA) METHOD: AUTO SURVEY, PRIMARILY COMMON NAME Domestic Geese Domestic Chicken Glaucous - winged Gull Common Crow Black - capped Chickadee Robin Starling Rufous -sided Towhee Oregon Junco Song Sparrow Unknown Mice Domestic Dog Domestic Cat Domestic Horse Domestic Cattle BIRDS NUMBER SEEN. OR ABUNDANCE 6 6 -10 9 1 1 2 1 3. 9 8 MAMMALS 3 12 3 2 2 -57- LOCATION Farm. Farm. Farm and overhead. Grove in ravine. Western fenceline. Throughout area. Farm. 46th Avenue Swamp. Orchards; brushy portions throughout area. Orchards; brushy portions of area. Brushy open areas. Throughout area. Throughout area. Near South 136th Farm. 2. Human Use and Development The area comprising the proposed LID is totally within the City of Tukwila. Portions of the ultimate service area are located in King County within the foster neighborhood to the south and the Riverton neighborhood to the north. These neighborhoods are included within the area loosely referred to as. the Sea -Tac communities. An extensive inventory of existing social as well as natural con- ditions has recently been completed as the first phase of the Sea - Tac Communities Plan, sponsored by the Port of Seattle and King County. The second two phases will entail data analysis and recom- mendations. Each phase will take six months to complete. Part of the first sixth month report included a discussion of community trends which were anlayzed_according to census tracts. The study area lies entirely within census tract 272. Chart 10 summarizes data pertaining to census tract 272. Figure I illustrates the existing land use of the LID area and its vicinity. a. 'Population Population growth in census tract 272 (Riverton - Tukwila Area) was greatest between 1940 and 1950, with considerable leveling off in the rate of growth thereafter. The population as an average whole is aging and will continue to do so as this area follows the national trend in lower birth rates. Elderly people make up a high percentage of the population (over 17?) in the Riverton- Tukwila area which has many long established homes where older persons of limited means can still afford to live. Although a great deal of urbanization has occurred in the Riverton- Tukwila area, overall population density is still relatively low. A number of factors have contributed to this low density including large areas in steep unbuildable slopes, poor platting practices which have rendered much land inaccess- ible, lack of sewers and large areas committed to non - residential land uses. Land use changes in and around the study area have contributed to high declining school enrollments (over 20% loss between 1970 and 1972). For example, highway expansion, and consequent reduction in residential areas, is a probable factor influencing declining enrollments. b. Housing Housing values and rents tend to be low in the neighborhoods of Riverton and Foster. In general, low rents correlate to census tracts having the highest incidence of units built prior to 1940. In 1968 the King County Department of Planning conducted -58- CHART 10 CENSUS TRACT 272 DATA Population. Median age of population Percent of persons under 20 years of age Percent of persons 65 years of age and older Persons per acre Percent of population moving between 1965-70 Non -white population School Enrollment Median number of school years completed Percent of high school dropouts (age 16 -21 not in school and not enrolled) Elementary enrollment change; 1970 -72 Housing Percent of multi- family housing units Percent of owner - occupied housing units Percent of total housing built 1960 to 1970 Percent of housing units built prior to 1940 Median value of housing Median rent value Income Median family income Percent of persons below poverty level Percent of persons receiving public assistance Percent of workers employed in transportation Percent of workers employed in blue collar jobs Percent of workers employed in professional and related services -59- CENSUS TRACT KING 272 COUNTY 20 to 25 40 to 50% 17 %+ Under 3 50 - 60% 4 %+ 12 to 12.5 10 to 15% 20% loss +.. 20 to 30% 40 to 50% 30 to 40% 20 %+ $16- 19,000 $110 -120. 25.4 37.0 8.8 6.9 12.5 9.2 29.1 63.2 31.2 $21,800 $118 $10- 12,000 $11,886 12 to 16% 5.0 2.5 %+ 1.9 8 -10% 7.9 50 -60% 35.9 10 -12% 18.2 Le leaf © Vacant' ED RemduchaQ CAD a1ru JluraQ Conmerc Q O Lift lar#ry ® Mu ©Ins#ilufiauQ irahlu' rack LAND USE FigiR, I —60— NO 0 200 400 600 1 acre a field "windshield" survey of housing quality. The purpose of the survey was to establish a basis for housing inspections and enforcement under the provisions of the county's minimum housing code. Housing quality was rated on a scale of 1 to 4, with 1 representing "sound" housing units, 2 being "basically sound ", 3 the "deteriorated" units, and 4 the "dilapidated" units. Sound and basically sound housing requires no substantial improvement or removal of houses but does require conservation measures and maintenance to keep the houses in good condition. Deteriorated housing needs more repair than would be provided in the course of regular maintenance. Such housing has one or more defects of an intermediate nature that must be corrected if the unit is to continue to provide safe and adequate shelter. Dilapidated housing does not provide safe and adequate shelter and in its present condition endangers the health, safety, or well being of its occupants. Such housing has one or more critical defects; or has a combination of intermediate defects in sufficient number or extent to require considerable repair or rebuilding; or is of inadequate original construction. The definitions for deteriorated and `dilapidated housing is identical to those used in the 1970 Census of Housing. In the Riverton and Foster neighborhoods located within census tract 272, 14.1% of the total housing units were determined to be deteriorated. This is a relatively high percentage. Neigh- borhoods south of Seattle in general have fewer than. 5% of the total housing units rated as deteriorated. Two nearby census tracts, 263, the Boeing Field and Duwamish neighborhoods and 264, the Glendale and Valley View neighborhoods, experienced an even greater percentage of deteriorated units, 31.2 and 18.8 percent respectively. The King County Planning Staff spot- checked the results of the above mentioned housing quality survey in the spring of 1973. For the most part it was determined that the 1968 results are still valid for overall neighborhood ratings on a percentage basis even though some individual units have been removed or changed from one rating category to another. Within the LID boundaries itself, there are six houses, one of which was noted in the above study to be dilapidated. Also, there are several other dilapidated structures in the LID boundaries including an old service station, a restaurant and repair garage. Within the probable, or eventual service area, there are an additional 18 houses, three of which are considered dilapidated (only one of the dilapidated houses is presently occupied). -61- C. ENVIRONMENTAL IMPACTS RESULTING FROM THE PROPOSED ACTION For the purposes of this discussion, impacts will be divided into two categories, primary and secondary. Primary impacts are those impacts which related directly to the construction and operation of the sewage and water system. Secondary impacts are those impacts which will result from long term land uses changes. 1. Primary Impacts Primary environmental impacts will be associated with the following construction activities: the use of vehicles, engines, augers, and other construction equipment; the removal or alteration of vegetation; the breaking of pavement and possibly the driving of piles; the excavation and backfilling of trenches; the compaction of trench back - fill; the clean -up and restoration of the surface; and the disposal of spoil. a. Noise and Atmospheric Impact Noise impact will occur as a result of some or all of the above enumerated construction activities. Noise impacts created by the construction of the proposed sewer and water lines will be significant in and adjacent to the construction site, however, such impacts will be temporary, affecting nearby areas for only short periods of time. Air compressor noise and the noise created by jackhammers, etc., if utilized, will be most noticeable. Some of the noisiest construction activities, such as pile driving to support the lift station, if necessary, and the tunneling (jacking) under the highway will occur at such distances from residential areas that significant reduction in noise impact to these sen- sitive receptors can be achieved. For example, jackhammers and rock drills create noise levels of 82 -98 dBA at 50 feet, and impact pile drivers create noise levels of 95 -105 dBA at 50 feet. These two pieces of equipment are among the noisiest that are likely to be utilized. Noise reduction of 4 -5 dBA can be achieved with a doubling of distance. Most noise associated with construction activities will occur in the daytime. Atmospheric conditions should not be significantly impacted by construction of the proposed project. Dust created during all phases of the project should be adequately controlled by the construction contractor and is not likely to become a nuisance. The operation of heavy equipment and the importation of back - fill, -if required, will have a slight to moderate impact on air quality depending upon microclimatological conditions, the equipment involved and the type of fuel used. b. Geological Impact The construction of the proposed sewer and water lines will require excavation averaging 12 feet for the sewer lines and 4 feet for the water lines. This will entail the removal of -62- the existing surface soils, peat, muck, and in some places, alluvial deposits. The trench beds may be layered with gravel. The excavated trench material, in most cases, peat, may be utilized as backfill. It is possible that the trench and pipe systems will either result in obstruction of groundwater flow, or due to physical phenomena under saturated conditions, water held in the adjacent soils may flow by gravity along the sewer and water routes. If lowering of the groundwater table results, the soils that are predominantly peat would settle. If the predominantly_ peat areas settle, the compacted trenches could be higher than the surrounding surface. To avoid this possibility, excavated material may be utilized for backfill and compaction will be minimized. If the areas comprised of predominantly peaty soils do settle, damage to existing buildings and structures would be highly unlikely as most of these buildings have been constructed on filled lots or on pilings. c. Hydrological and' Water Quality Impact Long term impact of the construction activities on groundwater quantity and quality is expected to be minimal, as explained above. Short term impact during the construction phase, is, however, probable. Dewatering of the soil along the proposed sewer and water routes, for example, will be necessary. Past experiences indicate, however, that the lowering of groundwater levels will be a temporary condition and the groundwater will assume its normal level upon the cessation of dewatering. The water removed will probably be discharged under controlled conditions into the existing nearby drainage canals and roadside ditches and is not expected to create any significant environmental impact. Water resulting from the dewatering process should be retained in a settling basin to minimize siltation to the stream. Long term water quality conditions will improve as additional residential and industrial areas are sewered and septic tank overflows are eliminated. At the present time the stream draining the study area is high in nitrates and nutrients, as compared to the Green- Duwamish River. In terms of quality, the stream could presently be considered to constitute a small point source of pollution to the Duwamish River. Sewering the areas which drain into the stream will in all probability reduce the stream's burden of nitrates and nutrients. High nutrient levels is one of the many water quality problems experienced in the Green - Duwamish River. By itself, the positive impact of the proposed action upon water quality of the Green - Duwamish River may be insignificant, due to the large volumes of the river relative to the volume of the stream. However, the multiplicity of discharges to the river must be viewed in terms of their cumulative impact upon water quality, and as such, even small discharges may be a factor contributing to upset conditions. Questions regarding the effects of upstream actions, such as changing land uses and changing input to the river systems, and resulting changes within the Green - Duwamish Estuary will be answered during the coming months as the RIBCO Study perfects its computerized estuary model. Until such time, the previous comments regarding the effects of the proposed action and future development within the study area must be considered speculative. d. Biological Impact Inasmuch as the proposed sewer and water lines will be placed within the existing roadways and roadway right -of -ways, minimal disruption to existing natural systems will occur. Most of the impact to wildlife habitats will occur as a result of development within the area of the proposed LID and its ultimate service area which will be possible when sewer and water service is made available (see Secondary Impacts). Also, resident fish populations should be benefited as the water quality of the stream which ultimately flows into the Green River is improved. However, the multiplicity of small discharges must be improved before this positive impact can be quantifiably assessed. Secondary Impacts Secondary impacts resulting from the proposed action relate to future, development which will be possible when sewer and water .service is made available. The King County Comprehensive Plan, which applied to the area within the proposed LID specified suburban residential land use for this area. This designation was to provide for orderly transition from a suburban land use to more intensive urban uses. This transition has in fact been occurring within the proposed LID, particularly since the time that the area was annexed by the City of Tukwila. Industrial development will undoubtedly result in the following environmental impacts which are typical in an urban situation: dust and noise from filling and construction activities; increased runoff containing hydrocarbons and particulates from paved surfaces; lowering of the water table due to decreased availability of permeable surfaces for infiltration; some increases in pollution from vehicular traffic; and reduction of areas suitable for wildlife habitats. Industrial development within the area included within the proposed LID may stimulate further industrial development on adjacent land within the Tukwila City Limits. Some of this land is flat, and if filled, would be suitable for more intensive uses. Areas outside of the Tukwila City Limits within King County which may ultimately be served by the proposed LID are likely to remain committed to low density residential purposes, steep slopes being the main limiting factor. As mentioned in the census data analysis, a number of other factors have contributed, in part, to low population density within this area as well. The population generally tends to be older and more persons are within low income categories than for King County as a whole. A disproportionate number of the houses are officially considered dilapidated or in poor condition. Due to topographic constraints, it can be tentatively hypothesized that land use in the ultimate service area of the LID may not change much. Secondly, that a sufficient number of the people residing there may be within an income range that may experience difficulties in paying assessments for sewer and water improvements. -65- D. UNAVOIDABLE ADVERSE EFFECTS The following is a discussion of possible adverse effects which might occur as a consequence of the development resulting from the proposed action and the mitigating measures which may be employed to ameliorate such potential effects. As mentioned in the previous section, there will be primary impacts which are related directly to construction and operation of the sewer and water improvements; and there will be secondary impacts which are related to long -term land use changes. Unavoidable adverse effects can only be postulated at this time. It is proposed that a subsurface investigation by qualified soils engineers be conducted in order to determine the proper methods and materials to avoid the possible adverse effects resulting from construction work. The construction mehtods and materials will then be specified in the construction contract: - The use of jack hammer, rock drills and other earth moving equipment should be limited to daytime hours when noise impact is less critical. Muffling devices should be used, if possible, when construction activities are in close proximity to residences. - Dust created during all phases of the project should be adequately controlled either .. by sprinkling of excavated materials or by provisions for storage of excavated materials until utilized as backfill. - Possible obstruction of groundwater flow can be avoided by re-utilizing excavated material for backfill and by minimizing compaction. - Water resulting from the dewatering process should be retained in a settling basin to minimize siltation to the stream. - Obstruction to local traffic patterns can be minimized by limited. construction activities to off peak hour times. E. ALTERNATIVES TO THE PROPOSED ACTION 1. Alternative Projects or Programs - Inaction. If no program is pursued, land within the proposed LID would remain without sewers and water service. Such an alternative would be contrary to the agreement between the City of Tukwila and developers within the proposed LID to connect to sewers as soon as possible. Further development within the proposed LID would be limited due to environmental constraints. Large cleared and partially filled areas with no effective drain fields for septic tanks would be difficult or impossible to utilize. Interim solutions such as the utilization of holding tanks for waste water collection are not conducive to long- term development of the area. Consequently, the large cleared and partially filled tracts of land would be rendered unuseable and would remain in their present unaesthetic condition. Occasional septic tank overflow problems in the areas committed to residential uses would continue. Input of oxygen demanding materials and nutrients to the stream, and ultimately to the Duwamish River, would continue. 2. Alternatives Within the Proposed Action In addition to the proposed scheme for collecting and disposing of sewage and for providing water, two alternative sewer systems and one alternative water system were considered. These alternatives and the reasons for their rejection are discussed below. a. Full Gravity System for Collection and Disposal of Sewage Wastes According to this alternative, an 8 inch gravity sewer would be constructed at minimum slope from the existing 18 inch trunkline northeast of Interurban Avenue, along South 133rd ,Street to South 134th Street. From this intersection, 8 inch gravity sewers would be extended southeast and northwest along South 134th Street with ultimate extensions to serve parcels on each side of the street. Due to grade interference caused by the twin 36inch storm drains under the .freeway, the line from Interurban Avenue would not be of enough slope to reasonably transport wastewater. This alternate, due to slope problems, could result in future maintenance difficulties. For example, if the system settled, there would be reduced flow and solids would settle. In .addition, even if pipes are placed at minimum slope, the resulting sewer would be too high to serve low areas northeast of South 134th Street without prohibitively expensive deep fills to raise the ground surface. It is estimated that a minimum of 7 feet of fill would be required for the southeast and at least 10 feet of fill would be required in the northwest portion of the ultimate service area so that a gravity system would be operable. A gravity system would thus preclude some of the exist- ing structures from sewer service until such time as this land is filled and converted to other uses. -67- b. Gravity Collection System with Lift Station at Northwest Corner The second alternative involves collecting all sewage in a gravity main on South 134th Street and then transporting sewage to a lift station site northwest of 43rd Avnenue South. Sewage would then be lifted and transported by force main to the existing 18inch trunk line northeast of Interurban Avenue. The force main would be routed to a connection point with the / existing 18" sewer line on the northeast side of Interurban. Either a new excavation under the freeway would be necessary, or subject to successful negotiations with the Val -Vue Sewer District, through an existing 18 inch pipe, under the freeway. This pipe was installed by METRO for the future use of the Val-Vue Sewer District. Although technically feasible, it was considered more expensive in first stage costs because of the more remote lift station location and deeper excavation northwest of South 133rd Street. c. Water Service Alternative - Single Connection According to this alternative, water would be provided through a single 12inch main located on South_133rd Street connected to an existing 12 -inch transmission main line on the northeast side of Interurban Avenue. 10 -inch branch mains would then extend along South 134th Street tb provide service within the proposed LID. Ultimately, 8 -inch extensions and loops could serve additional areas. This system, however, would be totally dependent upon a single connection to the existing city system. In the event of a line break, the whole area would be without water or fire protection. For this reason, this alternative would not provide the level of service necessary to provide adequate protection for existing or future development. -68- F. RELATIONSHIP BETWEEN LOCAL SHORT -TERM ENVIRONMENTAL USES AND MAINTENANCE AND ENHANCEMENT OF LONG -TERM PRODUCTIVITY. Short -Term environmental uses are primarily those impacts related to construction activities as well as the transition time in which the entire LID will be committed to industrial purposes. The area included within the proposed LID is undergoing rapid transition from suburban residential uses to industrial uses. Some of the areas to be served by later transition to industrial uses. Existing residential areas within the Val -Vue Sewer District which could ultimately be served by this system, in all probability, will remain residential. Long -Term economic productivity of the proposed LID will be enhanced by industrial development which will be possible as a result of the proposed project. Ultimately, as the residential areas within the Val -Vue District are served by the sewer system, septic tank overflow problems will greatly reduce threats to public health and welfare. In addition, the proposed sewer service will contribute to the long -term enhancement and preservation of the environment for existing and proposed uses as well as contributing to the enhancement of natural systems. G. ANY IRREVERSIBLE AND IRRETRIEVABLE RESOURCE COMMITMENTS WITH THE PROPOSED ACTION. The primary irreversible and irretrievable resource commitments required by the proposed project include the commitment of financial resources, man power, equipment and construction materials necessary to accomplish the proposed action. No additional commitments would be required other than the fuel and energy expended in routine cleaning and maintenance. The secondary irreversible and irretrievable resource commitments involve the commitment of land within the proposed LID to industrial uses and the probable eventual commitment of some adjacent residential areas to more intensive use. These land use commitments will preclude some future optional land uses. -69- APPENDIX CITY OF TUKWILA LID X24 BOUNDARY DESCRIPTION All that real property situate in the Northeast 1/4 of Section 15, Township 23N, Range 4 East, Willamette Meridian, in the City of Tukwila, King County, Washington, more particularly described as follows. Beginning at a point on the Northeasterly margin of South 135th Street (formerly Foster Street), said point also being the Southeasterly corner of Tract 15, as said street and tract are shown on that map entitled "FOSTORIA GARDEN TRACTS" which map was filed for record on September 10, 1901, in Volume 9 of Plats, page 95, Records of King County, Washington. Thence from said Point of Beginning Northeasterly, Southeasterly and Northeasterly, along the Tukwila City Limits Line as it exists on 11 -27 -73 and the Northeasterly prolongation thereof to the centerline of South 134th Street, thence Northwesterly along last said centerline and along the "FC Line" as said "FC Line" is shown on WSHD plans as established by Commission Res. No. 1356, September 25, 1963, to the intersection thereof with the "FD Line" as shown on said WSHD plans; thence Northeasterly along said "FD Line" to its intersection thereof with the centerline of South 133rd Street; and the easterly terminus of said "FD Line "; thence easterly along the centerline of South 133rd Street to its intersection with the Southwesterly right of way line of PSH No. 1 as shown on said WSHD plans; thence Northerly, Northeasterly, and Northwesterly along last said right of way line and its Northwesterly prolongation to the centerline of Relocated South 133rd Street as shown on said WSHD plans; thence Southeasterly along said Relocated centerline to the intersection thereof with the Southeasterly prolongation of the right of way line for said PSH No. 1, said line showing on said WSHD plans, as "S26 °20'E, 280' +; thence Northwesterly along said prolongation and line to the intersection thereof with the Southeasterly prolongation of the Northeasterly line of Lot 12, Block 4, Riverton Replat of Lot 1 to 5 of said Fostoria Garden Tract; thence Northwesterly along said prolongation and North- easterly line of Lot 12 to the most Southerly corner of Lot 8, of said block 4; thence Northeasterly and Northwesterly along the boundary of said Lot 8 to the Southeasterly margin of 44th Avenue South; thence Southwesterly along said Southeasterly margin and the Southwesterly prolongation thereof to intersect with the "FE Line" as shown on said WSHD plans; thence Southeasterly and Southerly along said "FE Line" to the intersection thereof with the centerline of South 133rd Street; thence Easterly along the centerline of South 133rd Street to its intersection with the Northeasterly prolongation of the Northwesterly line of Tract 17 of said Fostoria Gardens; thence Southwesterly along said prolongation and Northwesterly line of Tract 17 to the Northeasterly margin of South 135th Street (formerly Foster Street); thence Southeasterly along said Northeasterly margin to the POINT OF BEGINNING. -72- CITY OF TUKWILA LID 24 PRELIMINARY STUDY SEWER SYSTEM - PROJECT COST SUMMARY Construction Cost Contingencies @ 10% Sales Tax @ 5.3% Engineering Environmental Assessment Subsurface Investigation Preliminary Studies and Assessment Final Design @ 8% $ 69,060 6,900 Subtotal $ 75,960 2,000 1,400 3,640 6,080 Design Surveys @ 1.5% 1,140 Construction Surveys @ 2% 1,520 Construction Inspection @ 4% 3,040 Property Surveys @ 1% 760 Special Services Allowance 1,900 Legal Cost @ 3% City Administrative Cost Financing Cost @ 6% (Per City Treasurer) ' Bonding Costs (Per City Treasurer) Subtotal 4,025 21,480 2,280 -0- $103,745 6,225 -0- TOTAL PROJECT COST $109,970 -73- CITY OF TUKWILA LID 24 PRELIMINARY STUDY SANITARY SEWER - CONSTRUCTION COST SUMMARY 1. Lift Station and Wet Well 2. 4-Inch A. C. Force Main 3. 10 -Inch Casing 4. 8 -Inch Sanitary Sewer 5. Sanitary Manholes 6. 6" Side Sewers 7. 6" Side Sewer Tees L. S. 900 L.F. @ $ 9.37 90 L.F. @ 66.00 1540 L.F. @ 21.26 5 Ea. @ 670.00 100 L.F. @ 25.00 10 Ea. @ 10.00 Contingencies @ 10% Sales Tax 5.3% TOTAL CONSTRUCTION COST $16,000 8,430 5,940 32,740 3,350 2,500 100 $69,060 6,900 $75,960 4,025 $79,985 CITY OF TUKWILA LID 24 PRELIMINARY STUDY WATER SYSTEM - PROJECT COST SUMMARY Construction Cost Contingencies @ 10% Subtotal Sales Tax @ 5.3% Engineering Environmental Assessment 2,000 Subsurface Investigation 1,400 Preliminary Studies and Assessment 3,640 Final Design @ 6% 4,320 Design Surveys @ 1.5% 1,080 Construction Surveys @ 1% 720 Construction Inspection @ 3% 2,160 Property Survey @ 1% 720 Special Services Allowance 1,900 Legal Cost @ 3% $ 65,450 6,550 $ 72,000 3,820 17,940. 2,160 City Administrative Cost -0- Financing Cost @ 6% (Per City Treasurer) Bonding Cost . er i ty reas.urer) Subtotal $95,920 5,755 -0- TOTAL PROJECT COST $101,675 -75- CITY OF TUKWILA LID,24. PRELIMINARY STUDY WATER COST - SUMMARY 1. 12-inch cast iron water pipe 850 L.F. @ $ 23.17 2. 10 -inch cast iron water pipe 1520 L.F. @ 19.17 3. 8 -inch cast iron water pipe 100 L.F. @ 15.00 4. Fire hydrant assemblies 6 Ea. @ 550.00 5. 12 -inch tapping valve & sleeve w /MH 1 Ea. @ 1600.00 6. 10 -inch gate valve and box 2 Ea. @ 500.00 7. 8 -inch gate valve and box 3 Ea. @ 400.00 8. 20 -inch steel casing, bored 90 L.F. @ 89.00 Contingencies @ 10% Sales Tax @ 5.3% -76- - CITY OF TUKWILA LID 1124 PRELIMINARY ASSESSMENT ROLL December 18, 1973. Owner Assessment Area Assessment Assessment Assessment Total (Per County Assessor) Parcel No. S.F. Sewer Water Gen. Facilities Assessment Sylvia E. Jones 1 8,936 $ 906.98 $ 826.65 $ 486.76 $ 2,220.39 Charles M. F. Schmoll 2 16,000 1,623.95 1,480.13 871.54 3,975.62 William C. L. Wiese 3 16,214 1,645.67 1,499.92 883.20 4,028.79 William C. L. Wiese 4 6,266 635.98 579.66 , 341.32 1,556.96 D. R. Shannon 5 8,636 876.53 798.90 470,41 2,145.84 D. R. Shannon 6 9,657 980.16 893.35 526.03 2,399.54 Lee Walton 7 11,084 1,124.99 1,025.36 603.76 2,754.11 Mable Johnson 8 1,970 199.95 182.24 107.31 489.50 Jim Gayther 9 11,612 1,178.58 1,074.20 632.52 2,885.30 J. Frost 10 33,407 3,390.71 3,090.41 1,819.72 8,300.84 Key Properties 11 267,425 19,775.58 18,024.14 14,567.00 52,366.72 Key Properties 12 129,565 11,530.23 10,509.05 7,057.58 29,096.86 Ted E. Gusa 13 27,281 1,180.62 1,076.05 1,486.03 ' 3,742.70 Key Properties 14 5,990 249.01 226.95 326.28 802.24 Warren Neuroth 15 174,705 14,719.95 13,416.26 9,516.41 37,652.62 W. L. Neuroth 16 22,140 1,585.11 1,444.73 1,206.00 4,235.84 750,888 S.F. $61,604.00 $56,148.00 Assessment Rate for General Facilities Est. Project Cost Gen. Facilities Only $ 93,893 Ultimate Service Area 1,723,714 S.F. Square Foot Assessment $.0544713334 $40,901.87 $158,653.87 City Funding 52,991.13 Total $211,645.00 Project Cost