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Home My WebLink AboutSEPA EPIC-ND-25 - RSR DEVELOPMENT - CONVENTION CENTERCO \-VENTION CENTER INTERURBAN AV S & SOUTHCENTER BLVD EPIGND -25 CITY OF TUKWILA PLANNING DEPARTMENT STATEMENT OF DECLARATION File No. MF- 76 -6-SMP APPLICATION FOR DEVELOPMENT OF A CONVENTION FACILITY LOCATED EAST OF INTERURBAN AVENUE AT THE INTERSECTION OF SOUTHCENTER BOULEVARD AND INTERURBAN AVENUE. Applicant - RSR Development Inc. INTRODUCTION: The following is a Statement of Declaration by the undersigned as the Responsible Official pursuant to Title 18.98 of the Tukwila Municipal Code and the Washington State Environmental Policy Act of 1971. An Environmental Questionnaire and additional information has been completed on the proposed legislation and has been taken into consideration in this Declaration. DECLARATION: Based upon the Environmental Questionnaire and additional infor- mation as prepared, Section 18.98 of the Tukwila Municipal Code dealing with environmental policy and the guidelines issued by the Washington State Department of Ecology for the implementation of the State Environmental Policy Act, I find that the proposed appli- cation will not have a significant effect upon the environment and therefore a complete Environmental Impact Statement is not required. PLANNING DEPARTMENT This negative declaration is made conditioned upon mitigating measures being taken on those issues identified in the environmental quetionaire and it's attachment per section 18.98.070 of the Tukwila Municipal Code. 544. 3/3o%/G Kje 1 Stoknes, Director (Date) KS /cw CITY OF TUKWILA ENVIRONMENTAL QUESTIONNAIRE This questionnaire must be completed by all persons applying for permit from the city of Tukwila, unless it is determined by the Responsible Official that an environmental assessment or full impact statement is required. Other forms have been developed for single - family home applications and legislation proposals. 367 3-7-tAi f(A7`rc' ' J BACKGROUND DATA: 1. Name of applicant:RSR Development Inc. 44 k4L/A64 2. Address and phone of Applicant: 3. 4. Project location: Interurban Avenue near I -405 5. Nature and brief description of proposal: 70,000 sq. ft. convention tenter with 638 parking stalls. 6. Estimated completion date: December 1976 7. Do you have any plans for future expansion, if yes please explain: No. • Project name: The Chameleon Convention and Banquet Facility What other governmental permits are required prior to completion of this project? (a) Rezone, conditional use, substantial development, etc. YES NO x G' YES-x. (b) King County Hydrolics Permit NO (c) Building permit YES x NO (d) Puget Sound Air Pollution Control Permit YES NOx (e) Sewer hook up permit YES X NO (f) Sign permit YES x NO (g) Water hook up permit YES x NO (h) Storm water system permit YES x NO (i) Curb cut permit YES x NO (j) Electrical permit (State of Washington) YES x NO (k) Plumbing permit (King County) YES x NO (1) Other Shorel ine Management Substantial .Development Permit. 9. Do you know of any plans by others which may affect the property covered by your proposal? If yes, explain: No. 10. Agency requiring checklist: City of Tukwila, Department - ?WA/ 11. Accepted by agency on: Pe, fv r) (o • by : G . C✓u.4cir 4 e Id (to be filled in by city u on receipt of checklistT ENVIRONMENTAL IMPACTS (Explanations of all "yes" and "maybe" answers are required.) Yes Maybe Earth. Will the proposal result in: (a) Unstable earth conditions or in any changes in geologic sub- structures: (b) Disruptions, displacements or overcovering of the soils: (c) Change in topography or ground surface relief features? (d) The destruction, covering, or modification of any unique geologic or physical features? (e) Any increase in wind or water erosion of soils, either on or off the site? (f) Changes in deposition or erosion of beach sands, or in changes in siltation, deposition, or erosion which may modify the channel of a river or stream or the bed of the ocean or any bay, inlet or lake? Explanation: Air. Will the proposal result in: (a) Air emissions or deterioration of ambient air quality? (b) The creation of objectionable odors? (c) Alteration of air' movement, moisture or temperature, or in any change in climate, • either locally or regionally? Explanation: See Attachment. X x x Water. Will the proposal result in': (a) Changes in currents, or the course or direction of water movements, in either marine or fresh waters? (b) Changes in absorption rates, drainage patterns, or the amount of surface water run- off? (c) Alterations to the course or flow of flood waters? (d) Change in the amount of surface water in any watercourse? (e) Discharge into surface waters, or in any alteration of sur- face.'water quality, including temperature or turbidity? (f) Alteration of the direction or rate of flow of ground waters? (g) Change in the quantity of ground waters, either through direct additions or withdrawals, or through interception of an acquifer by cuts or excavations? (h) Deterioration in ground water quality, either through direct injection, or through the seep -. age of leachate, phosphates, detergents, waterborne virus or bacteria, or other substances into the ground waters ?. (i) Reduction in the amount of water otherwise available for public water supplies? Explanation: • See Attachment. -2- Maybe Flora. Will the proposal result in: (a) .Change in the diversity of species, or numbers of any species of flora (including trees, shrubs, grass, crops, micro -flora and aquatic plants)? (b) Reduction of the numbers of any unique, rare or endangered species of flora? (c) Introduction of new species of flora into an area, or in a bar- rier . to the normal replenishment of existing species? Explanation: See Attachment Yes Maybe Fauna.. Will the proposal result in: (a) Changes in the diversity of species, or numbers of any species of fauna (birds, land animals including rep - tiles, fish and shellfish, benthic organisms, insects, or micro - fauna)? (b) Reduction of the numbers of any unique, rare or endangered species of fauna? (c) Introduction of new species of fauna into an area, or result in a barrier to the migration or movement of fauna? (d) Deterioration to existing wildlife habitat? Explanation: See Attachment Noise. Will the proposal increase exist -` ing noise levels? Explanation: See Attachment -3- Light and Glare. Will the proposal produce new light or glare? Explanation: See Attachment Land Use. Will the proposal result in the alteration of the present or planned land use of an area? Explanation: Natural Resources. Will the proposal re- sult in: (a) Increase in the rate of use of any natural resource? (b) Depletion of any nonrenewable nat- ural resource? Explanation: Risk of Upset. Does the proposal involve a risk of an explosion or the release of hazardous substances (including, but not . limited to, oil, pesticides, chemicals or radiation) in the event of an accident or upset conditions? Explanation: Population. Will the proposal alter the location, distribution, density, or growth rate of the human population of an area? Explanation: -4- Housing. Will the proposal affect existing housing availability, or create a demand for additional housing? Explanation: Transportation /Circulation. Will the pro- posal result in: (a) Generation of additional vehicular movement? (b) Effects on existing parking facilities, or demand for new parking? (c) Impact upon existing transportation systems? (d) Alterations to present patterns of circulation or movement of people and /or goods? (e) Alterations to waterborne or air traffic? Explanation: See Attachment Local Services. Will the proposal have an ,effect upon, or result in a need for new services in any of the following areas: (a) Fire protection? (b) Police protection? (c) Schools? (d) Parks? (e) Maintenance of public facilities, including roads? (f) Other' governmental services? Explanation: See Attachment -5- Energy. Will the proposal result in: (a) Use of substantial amounts of fuel or energy? (b) Demand upon existing sources of energy, or require the development of new sources of energy? Explanation: Yes Maybe No Utilities. Will the proposal result in a need for new systems, or alterations to the follow- ing utilities: (a) Power or natural gas? (b) Communications systems? (c) Water? (d) Sewer or septic tanks? (e) Storm water drainage? (f) Solid waste and disposal? Explanation: • Human Health. Will the proposal result in the creation of any health hazard or potential health hazard (excluding mental health)? Explanation: Aesthetics. Will the proposal result in the obstruction of any scenic vista or view open to the public, or will the proposal result in the creation of an aesthetically offensive site open to public view? Explanation: Recreation. Will the proposal result in an impact upon the quality or quantity of ex- isting recreational opportunities? Explanation: Yes Maybe No Archeological /Historical. Will the proposal result in an alteration of a significant archeological or historical site? Explanation: Revenue. Will the proposal cause a signifi- cant.increase in city revenues? Explanation: Employment. Will the proposal create a significant amount of new jobs? Explanation See Attachment CERTIFICATION BY APPLICANT: I hereby certify that the information furnished in this environmental checklist sheet is true and accurate to the best of my knowledge. CITY OF TUKWILA Sign ture and Title Project Name: G, /. A,tE Project Address: Sd,_.rkic6,"-re- --4_ /Ie JD /4/76.1. 046') 7 kc✓tcif /'/ Date BELOW THIS LINE FOR CITY USE ONLY ACTION BY OTHER.DEPARTMENTS: Check one Date of Review: Building by: (+) or ( -) Planning by: ( +) or ( -) Engineering by: ( +) or ( -). Police by: ( +) or (-) Fire by: ( +) or (-) 2. Agency review of environmental checklist determined that The project is exempt by definition. The project has no significant environmental impact and application should be processed without further consideration of environmental affects. project has significant environmental impact and a complete environ- mental. impact statement must be prepared prior to further action for permit More specific information is needed to determine impact. Signature and. Title .of Responsible Official 3. Applicant was notified of decision on: 'by Date Date by Staff Person Letter, phone ' In accordance with Washington State Environmental Policy Act'and City of Tukwila Ordinance No. 759. ( +) Means recommend a full environmental impact statement be'done. (--), Means recommend a full environmental impact statement not'be done: City of Tukwila Environmental Questionnaire for The Chameleon Convention Center and Banquet Facility by RSR Development Inc. Explanations and Supplemental Information Earth: Impacts to topography, geology and soils are expected to be minima in as much as the subject site was covered years ago with artificial fill derived from land cuts resulting from freeway construction.. Retention of existing vegetation and anticipated supplemental plantings along the river levee will help prevent surface water erosion and .minor,., landsliding. Air: Although some contribution to the existing level of jaii t r contarninents will result from vehicular pollutants associated with increased traffic to the site, their impact is expected to be neglegtible in relation to current traffici pollutant levels generated by major arterials adjacent to and in the vicinity of the site. Water: Paved surfaces associated with the proposed project will unavoidably inhibit ground water recharge and will result in a srrtall but probably measurable drop in the local water table, Surface run-off from 'paved areas will be diverted into the existing storm drainage system recently constructed on the site under the City of Tukwila, Public Works Project L.I.D. No. 25. Run-off from paved areas over levee embankments and landscaped areas will be avoided. 30% of the site area will be left in a natural state or new landscaping and plantings jn an effort to minimize overall run-off impacts. Flora: The natural botanical population on the site was destroyed some time ago though a few small remnants exist at the eastern end near the steep river. embankment. Trees and shrubs are absent. Landscaping re- introduced to the site in conjunction with the proposed action will be of species naturally occuring in the undisturbed areas along the Green River shoreline. City of Tukwila Environmental Questionnaire Explanations and Supplemental Information Page 2 Fauna: Although construction of the proposed complex is a part of a continuing trend of development along the Green River, the cumalative adverse effects to biological systems are expected to be minimal. Herbaceous ground cover was removed from the site some time ago and subsequently„ its value as a bird foraging habitat was lost. Existing vegetation on river banks will continue to provide food and shelter for many of the animal species presently using them Noise: Although noise generated on the site will increase during construction activities, it shall be of a temporary nature, short in duration; the long range npise impact of the proposed action is not expected to be significant. Light and Glare: Exterior accent lighting on the building and parking lot lighting will increase night lighting in the immediate vicinity of the building. Lighting will be kept to the minimum necessary for security and safety. Significant impact to the surrounding activities due to glare is not expected. Transportation /Circulation: The current traffic loads on area streets and arterials ip not expected to be significantly effected by increased traffic due to activities associated with the proposed project. No traffic problems are anticipated and adjacent arterials should function adequately. Traffic impacts should be further reduced by the probable scheduling of the majprity of vehicular loading and unloading at the site to correspond with off peak traffic hours. Local Services: The proposed project is not expected to place a significant demand upon any local services. Employment: The proposed project is expected to create as many as 25 tp 30 employment opportunities. MINI -MEMO TO 14 -Z t (lrrcli FlcmAN Steven M. Hall, P.E. Public Works Director Department of Public Works City of Tukwila 6230 Southcenter Blvd., Tukwila, Washington 98067 SUBJECT 'ft S V. U�.fI 1��tc.. DATE JO fc4Q -7& (a) MA)Sw`c 14 YES. 2 . WAree. 620 s tin v L.4 Et •ies (e) sHouLo ro Merl BE 3 . I 9"),SP Orcrerri ou (c.) Stnu 6113c o2'65 • ,11 It SIlaNED 4 Dear Planning Department: This type of facility (Convention and Banquet) generates an uneien demand for police services; ie, many persons demanding parking at the same time and several hours later leaving at the same time to enter on an arterial street. A police department would also expect to be called on the occational drunk, theives preying on unlocked vehicles in the lot. As a matter of good business on their part it would be wise for them to have persons to direct traffic at the onset and exiting times, then inbetween those times patrol the parking lot for protection of property. Much like the schools do for varsity football games. JAS • 206/324 -8780 WILLIAM S. TSAO & COMPANY PS. Engineers & Architects Lyle N. Kussman, Architect 2367, Eastlake Avenue E. • Seattle, Washington 98102 March 17, 1976 Kjell Stoknes Planning Director. City of Tukwila 14475 59th Ave. South Tukwila, Washington Re: Environmental Questionnaire, The Chameleon Convention Center, Tukwila, Wn. Dear Mr. Stoknes: We have attached the supplemental information for the proposed Chameleon Convention Center requested in your letter of March 11, 1976. We hope that this information adequatly fulfills your need for additional data and that a threshold determination will be forthcoming. If additional information or discussion is required, contact us at 324 -8780. WST: bt attached: supplemental information Sincerely, w William S. sad DECEIVE MaR 2 z 1976 am OF rmcwuA TRAFFIC Existing Traffic Daily traffic loads carried by streets and highways in the vicinity of the site shown on figure no. 1 are based on current counts available at the City of Tukwila and the District 1, State Highway Department. Peak traffic hourly loads are from measurements, or when not avail- able, are calculated on the basis of 9% of the daily volume. Morning and evening peak loads are expected to be the same. On -Site Traffic 660 parking stalls will be provided on -site for the convention center activities. Actual vehicular volumes resulting from the operation of the proposed facility are difficult to predict due to the variety of activity which may occur at the center. For instance, banquets or performances at the facility (generally occuring on evenings and weekends) will generate higher peaks but lower daily traffic volumes than exhibitions with less defined starting and ending times. It is possible that a large banquet or performance, or several smaller banquets commencing simultaneously would generate a 500 -600 vehicle per hour peak load both before and after these events. A particularly day may occassionally have two cycles of this level of use occuring in the afternoon and evening and could poten- tially involve 1200 -1500 vehicles per day in 3000 vehicle trips to and from the site. Exhibition activities running throughout the day would generate a different traffic loading pattern both in terms of volume and timing. Lower peaks might be expected due to events not having definite or restricted beginning/ arrival, ending /departure times. Peak periods might be expected near opening and closing times, but these are difficult to predict and in many cases would be only slightly higher than hourly averages. High turn -over rates at these events could potentially generate 4000 or more vehicle trips per day, peaks however, may not exceed 400 vehicles per hour. The above figures represent rough estimates at maximum usage of the parking facility at large, successful events. Normal daily average usage of the facility is expected to be lower and may generate 40 % -50% of these figures, averaging smaller events occuring at the facility with occassional maximum usage. Table 1 below summarizes these estimates, Type of Activity Banquets & Performances 1200 350 3000 Exhibitions 2000 300 4000 400 Table 1 (Vehicle Trips) Average Day Heavy Use Day Daily Avg. Hourly Avg. Daily Avg. Hourly Avg. 550 Max. Conditions - 2000 350 4000 550.:: -55- QC)3' _( Figure 2 indicates the estimated average daily traffic loading in the vicinity of the site following completion of the proposed project. In assigning traffic to the roadway network, the basic assumptions are that travel time will be the dominant consideration and consequently, eighty percent (80 %) of users will be freeway oriented. Of that 80 %, 65% are assumed to be westbound and 35% assumed to be eastbound. Of the non - freeway users, eighty percent (80 %) are expected to be oriented to local regions lying south and southwest in the vicinity, of Kent, Auburn, and Southcenter, Other Vehicles Generating Uses In The Area Other vehicles generating uses in the area include Southcenter com- mercial shopping area, local industrial areas, and the King County Park which is currently being developed adjacent to, the site. Peak traffic loads in moring and evenings to these:. commercial and industrial areas are not expected to correspond with peak traffic generated on the site. Operation of the park may correspond with some events at the convention center, particularly in the case of exhibitions on weekends However, these occurances are not expected to correspond to peak rush hour traffic. Furthermore, park oriented traffic is not expected to correspond to convention center traffic and its peak loads or direction of travel. Actions To Mitigate Impacts The major factor in the mitigation of traffic impacts on the vicinity of the site will be the scheduling of events at the. Center. Successful operation of this Center will depend greatly on easy access to the site's parking facility. For this reason, every effort will be made to schedule peak Center uses to correspond with off -peak traffic periods on I -405 and local arterials. Modification of traffic signaling devices at the intersection of Interurban. Avenue, Southcenter Blvd., and the site access road could further serve to regulate peak periods of discharge from the traffic area. The combination of the two suggested actions above is expected to maintain the overall impact of the traffic associated with the proposed facility at a minimum. No significant problems are expected due to vehicular traffic generated by the project, wi I . (.,)1 -42„. 1 ? ?A e,lopp1vYy1. HYDROLOGY AND WATER QUALITY Natural Setting The subject site is situated inside a meander loop on a mature river flood plain, topographically expressed as a broad flat - floored valley delimited by Tukwila and Riverton Heights Uplands on the north and west as well as the Renton Highlands on the east. In general, the valley's natural topography has been altered by construction of flood control levees, stream channelization, highway cut and fill, railroad embank- ments, as well as extensive and on -going filling for land development. Relief on the flood plain is generally less than 5 feet. Regional relief is 400 to 600 feet. The project area has a mean elevation of approximately 25 feet. Surface water that runs off the site flows directly into the Green River. River Flow Conditions The U.S. Geological Survey has maintained a gauging station on the Green River near Tukwila since October 1960. From that date through the 1971 water year, the average discharge was 1,491 c.f.s. (cubic feet per second). Typical maximum flood flows presently reach 9,000 to 12,000 c.f.s. at the subject site. During these flows,;: the water surface elevation of the Green River reaches an elevation of 24.3 at the upstream property line and an elevation of 22.8 at the downstream property line. The average recorded minimum flows are often less than 300c.f. s. adjacent to the subject site. The water surface of the Green River during these extreme low flow periods varies between four and six feet above mean sea level. Flow has been regulated since 1962 by Howard A. Hansen Reservoir for flood control during the wet season and for possible augmentation during the drier months. At the Tukwila station, the drainage area of the Green River is 440 square miles. Subject Site Surface Water Run -Off Water entering the Green River undergoes a complex hydrological cycle involving oceans, land, atmosphere, energy input from solar radiation, topography, soil and geological conditions, vegetation and man made features. The interaction of transportation from plants, evaporation, soil infiltration, and duration and intensity of rainfall regulate the surface water . runoff portion of this cycle. • ' Duration/ Recurrence interval 2 yr. 5 yr, 10 yr. 25 yr. 50 yr. 30 min. .4 .5 .6 .6 ` .7 1 hour .5 .6 .7 .8 .9 2 hour .7 .8 1.0 1.2 L5 3 hour .9 1.2 1,6 1,7 2.0 6 hour 1,5 1.8 2.0 2.5 2.8 Duration/ Recurrence Interval 2 yr. 10 yr. Zr yr. 12 hours 2.0 • 2.5 3.0 3.2 24 hours 2.5 3.0 3.5 4,0 48 hours 3.0 4.0 4.5 5.0 50 yr. 3.5 4,2. 96 hours 4.0 4.5 5.5 6,0 Table 1 : Amounts of rain falling in a given time period for various recurrence intervals. -43- � .S 7.0 Subject Site Surface Water Run -Off (cont'd) Evaporation and transpiration from plants and plant surfaces can be accountable for up to 70% of the recycling of water back into the atmos- phere in mature native vegetative cover. The subject site, however, falls far short of such a mature ecosystem. The subject site was covered years ago with artificial fill derived from land cuts resulting from area freeway construction. The natural bot- anical population on the site was destroyed due to this action. Trees and shrubs are absent and a moderately dense growth of wild grasses and clover covers a fair percentage of the site. Some areas are devoid of vegetation. Preliminary soils investigations indicate a substantial thickness of fill covers the site, generally 8 -12 inches thick. Fill consists primarily of silt and sandy silt. Native soils underlying the fill are almost exclusively grandular sands. Storm water run -off calculations are at best, estimations, however studies conducted in the subject site area by RIBCO and research by various governmental bodies is of assistance in estimating the impacts of the proposed development. Run -off quantity calculations for the subject site were based on the em- pirical method in this instance, McMath's Formula was used: Q = Act 5(S where Q = runoff in cubic feet per second A = drainage area in acres c = infiltration coefficient i = rainfall intensity in inches /hour S = slope in feet per 1000 feet The total site area is 10.973 acres. The existing impervious area is taken as 5 %. Proposed development would cover 6.88 acres of the site area with impervious building and paved surfaces yielding approximately 65% impervious surface on the developed site. Selection of proper in- filtration coefficient values is critical to the accuracy of run -off values determined by this method. For the existing site conditions, a coefficient of 0.15 was selected, based on soil conditions mentioned above, and a value of 0.62 was given to the developed site. These figures correspond well to the findings of both by both zone methods for rectangular areasl: and es- timated values presented by Merriman and Wigging for various soil types. The slope of the site was considered to be 1 in the existing condition and 2% following development. Rainfall was taken from Table 1 and is based on 5 year storm. 1. Metcalf & Eddy: "Sewerage and Sewerage Disposal" 2. Merriman & Wiggin: "American Civil Engineering Handbook" Viewridge (VR 1) Viewridge (VR 2) South Seattle (SS 3) Southcenter (SC 4) Lake Hills (LH 5) Highlands (HL 6) Central Business District (CBD 7) Table 2 Mean Percentage of Stormwater Run -Off 13.6 33.8 34.9 53.9 7.4 Subject Site Surfacs Water Run-Off (cont'd) Existing site: Developed site: Q= 10.973 (.15) (.6 Q = .97 c.f.s. Q = 1O.973(.62)(.6) ( 20 10.73 Q= 4.53c.f.s. These figures indicate 15% and 68% stormwater run -off respectively during a five year storm over a one hour period. Mean percentages of storm water run -off over a longer period would yield much lower results. In 1973, RIBCO conducted a water quantity and quality monitoring program in the Green River Basin. Over a period of 6 months, from February to September. Their results are indicated in Table 2. Seven storms occured during the testing period. The main percentage storm water run -off of these storms at the Southcenter testing; station; (Scd) was 53.9 %. Using the 2 year storm figures presented in Table 1, the developed subject site percentage of run -off is 57% which compares fav- orably to the Southcenter figures taken over a shorter period. Green and Duwamish River Water. Quality • The Green River, originates on the west slope of the Cascade Range and flows north and east about 60 miles to a point at 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 recieving industrial, municipal, and storm water wastes since the early 1900's In 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. 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 trunklipes and treatment plants is completed in accordance with Metro's Comprehensive Plan. The Renton treatment plant is located directly across from the subject site and discharges treated effluent at that point. Green and Duwamish River Water Quality (coned) 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 services area has been enlarged. The design capacity of the present Renton secondary treatment process is 36 million.gallons per day, although the actual volume of effluent varies. 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 re- placed 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. 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- Duwarnish still experiences 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 oxygen levels at the point of discharge. The RIBCO analysis indicates low- dissolved oxygen levels are still a problem. Lo- dissolved oxygen in the Duwamish River is attributable' to oxygen con - sumption by benthcis (bottom organisms) and algae as well as high temperatures due to shallow depths, low flows, and inadequate shading. 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. Dissolved oxygen is a key parameter' 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. The dissolved oxygen is depleted by the oxidation (degradation) 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 of the general amount and persistence of pollutants. Green and Duwamish River Water Quality (coned) The capacity of water to retain dissolved oxygen is al increasing temperatures. o reduced with 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 the Renton station are lower than at the Kent station. The RTP is designed for a B.O.D. treatment efficience 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 to just upstream of the RTP 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 Rainier; Vista Treatment Plant effluent, then the influence of.Elliot Bay seawater is registred. Ammonia and phosphate concentrations in the Duwamish River Estuary increased significantly downstream from the Renton Treatment, Plant out- fall 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 at least doubled as a result of the pre- sent 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 U. S. G. S. study indicates that in the case of the Duwamish River, nutrient concentrations do not control the occur - ance of the blooms in<as much as nitrogen and phosphorous compounds always are present in sufficient quantities for a bloom to exist. For example, previous data indicates that a bloom occured prior to the installation of the Renton Treatment Plant. The chief factors controlling whether or not a phytoplankton bloom will occur are favorable hydrological and climatic ,conditions. Green and Duwamish River Water Quality (cont'd) 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. 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 3 for additional water quality data Soluble trace metal concentrations for copper and lead (Table 4) are'frac- tions of a part per billion in the, estuary water. These data were obtained frpm the trace metal laboratory, University of Washington, Department of Oceanography, core sampling within the estuary. The fate of metals borne by the river 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 4) are extremely high and demonstrate how'effec- tively the transfer proceeds. The cores were obtained in June, 1973, and were analyzed by the Region Ten Environmental Protection Agency Labor- atory. Since nearshore' ocean sediments contain an average of 60,000 pph lead and 150,000 pph 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 site 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. Green River Water Quality at Subject Site 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 dependant on an an- alysis of individual parameters occuring within the river and comparing them to DOE water quality standards. See Table 3 for recent water quality obtained by Metro. 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 exceeding 1,000 when associated With any fecal source. However, this stretch of the Green River is subject to a special condition allowing a variation from the usual coliform criteria. JJL I FORM COUNTS/100 11L MEDIAN MT:TRO RESEN T STATION MONTH- 301 90 306 2,003 307 5,700 3077 800 310 6,R00 3107 2,700 - 351 510 i,60o -- 740_ DISSOLVED LAST LAST FECAL- AMMONIA NITRATE PHOSPHOROUS TEMPERATURE OXYGEN MONTH- YEAR COUNT ma/ I 1 CG::.UCTIVITY umhoslc,m2 430 33. 6,1-cO 2,300 :190 .31 9,400 -- 3,400 -180 .30 53 25.32 2,000. 510 .60 1,200 1,900- 30 .20 .46 20 20 12.25 .36 .25 15.7 36 ..24 15.5 .87 4.35 17.2 .40 .38 16.4 .23 16.6 39 4.75 20.0 .13. - 15.9 00.9 110 7 113 WATER QUALITv KENT TO ELLIOTT BAY AUGUSTj973. MEDIAN METRO P; ESE:.T STATION MONTH COLIFORM COUNTS/100 ML LAST MONTH-- .LAST FECAL COUNT AMMON I A m9/ 1 - NITRATE -e/1 ,301 307 3077 3106 3107 351 315 17,tiC. 5,700 224-+ 800 -- - 2,600 6,800 1,700 8.803 2,700. 2,600• 51 510- 2,200 -. 1,600• 950 14<C 1,000 1,100 270 PHOSPHOROUS - TEMPERATURE ma /1 C .33 400 .49 .61 49 3.10 20 15.00 20 .45 .58 :34 37 11 - 52 23 - 20 6.12 3.60 3.85 28 -.13- :50 .1U • .40 DISSOLVED OXYGEN no/1 7.9 C0LIFORet -- COUNTS %100 ML. MEDIAN - i METRO R0 PRESENT LAST LAST FECAL r riNON IA NITRATE STATION MONTH MONTH YEAR COUNT 0/ 1 ,:;a,' 1 301 306 10,000 _ 16,000 6,600 260 .26 .88 307 5,300.: 17,L02 6,300 320 14 44 3077 440 330 110 28.35 .20 3106 620 2,600 3,800 20 .80 .64 -- .36 3107 5,600. 8,300 _12,000 55 .23 .60 351 440 51 980 58 6.00 3.10 6.10 3108 5,700 2,200 2,900 100 16 .52' �5 315 2,700 1,400 720 500 1+ y0 . :17 - 13.5 - PHOSPHOROUS TEMPERATURE mg /1 C .36 15.0 12.8 20.0 15.8 15.8 15.3 D I SSU'L E 3 /.Y0E, CG'4DUCTIV 1 TY 138 TABLE3 (Cont'd. WATER QUALITY KENT TO ELLIOTT_ 3AY' JUNE 1973 METRO SIA ;CN MEDIAN MONTH COL1FORM COUNTS /100 ML LAST TLAST MONTH YEAR COUNT FECAL AMMONIA mo /1 71SSOL1'EL NITRATE-- PHOSPHOROUS TEMPERATURE OXYGEN 17q /1. m0 /1- CONDUCTIVITY oc /crE.2 301 4i 5 Ji 306 6;40 3,300 2;900 307 5;40 0 4,600 2,300 3 , 400 6,700 3077 J, • 5105 1-,400 2,500 7 90 3107 1,200 983 560 351 110 20 8o 3108 - 700 540- 1,700 • 870 22 120 - . . 48 -- 50 -24- 16:3 50 -- .11 .26 .09-i 12.8 20 "21:25 1.28 4:80 -_17.0 42 .70 .50 .35 17.1 - 20 .38 .49 .26 17.2 20 -- 02 5.20 18.8 .49 20 17.2 it 151 TABLE 4 METALS CONCENTRATIONS IN bUS /A11I SH ESTUARY .(ppb) Depth Locat on (Meters) Vest Waterway West Waterway East Waterway • East Waterway Sediments (Total Acid Soluble) Location Duwamish Mouth - Dt1wamish Mouth Duw;mish Mouth East Waterway -37- 0 15. 8 17 0 15, 3 8 13 Depth (Meters) 0 0 0 0.15 0.15 0.4 0.4 0.4 0.07 0.4 1.9 0.5 Pb 0:16 0.40 u, 0.44 0_.13 Pb Zn 71 000 194+ 000 ,152,000 195,000 18,000 346,000 61,000 1.30,000 25,000. 20,000 40u,00U '69.9 000 ';600 ; 000 146 ;000 Green River Water Quality t Subject Site (cont'd) At this location, total coliform organisms shall not exceed median values of 1,000 with less than 20% of the samples exceeding 2,000: when ;, associated with any fecal source. Dissolved oxygen shall exceed 8.0 mg /l for freshwater. Temperature shall not exceed 65° F (18.3 °C). ph shall be within the range of 6.5 to 8.5. Run -Off Water Quality at Subject Site The net'effect of this particular project will be small. As previously mentioned, the primary water quality problems associated with the Green River are; 1) low dissolved oxygen in the lower reaches from July through Septmber due to diurnal variations, 2) high coliform counts in the lower reaches throughout the year, and 3) high nutrient inflows, especially in the lower reahces and in the Duwamish Waterway. Urban debelopment and consequent run -off is one of the probable causes of the existing water Quality problems. Table 5 indicates probable waste loadings of the subject site in its current and developed states. Table 6 is reprinted from the 1974 RIBCO Urban Drainage Study (Appendix C) mentioned earlier,which indicates their find - ings of urban run -off quality characteristics during the 6 month study period. Particularly interesting in regards to this project are the findings, for the Southcenter (commercial) test site. The data from this test site is presented in greater detail in Table 7. Hydrological and Water Quality Impacts Summary and Mitigating Measures` As mentioned above, the net impacts of this particular project will be small. Total increase in storm water run -off during a 5 year storm can be expected to be approximately 3.5 c.f.s. impacting a flood stage flow adjacent to the site of approximately 9,000 to 12,000 c.f.s. As slight as this impact appears, admittedly it is a part of a continuing deleterious trend in accomodation of increased storm water flows by direct discharge into existing natural systems. Increased impervious surfaces will inhibit groundwater recharge and will result in a small but probably measurable drop in the local water table. The proposed action will further contribute to water quality problems due to increased run -off. Suspended solids, hydrocarbons, and heat in surface . run -off will also increase. The make -up of this run -off will probably be similar to that indicated in Table 7 impacting water quality as indicated °in, Table 3. The net effect will probably be minimal. Impervious Area Biological Oxygen Demand (BOD) Imp.1 lb /ac /day Per.2 lb /ac /day Sub.3 mg /1. Conductivity mhos Amp.' mhos /ac /day Per. mhos /ac /day Sub, mhos /cm3 . Tot al•Coliforrn Organisms Imp. J04/ac/dayV Pen. ;104 /ac /clay Sub.- ng /100m1 Fecal Coliform Organisms ln�p. 106 /ac /day ' 10-50 Per.`106 /ac /day 10 -50 Sub. jig/ 100 rn l' 50 -200 WASTE LOADINGS PER ACRE. TABLE 5 Existing Developed Site Cond i t i ons' Si teCondi t ions 5.0 .o18 -.02 .018 -.02" 0.5 .5 -1.4. .5 -1.4: 75-100 500=1000 WO-1000 100-1000 Organic Nitrogen Imp. 1b /ac /day Per. l b /ac /clay S,ub.. nig/ 1 NH3 Irnp. lb /ac /day P r. 1,b/ac/day Sub. mg /1 NO3 imp lb /ac /day Per. lb /ac /day Sub.`mg /i Poi 1b /ac /day Per; ;lb/ac/day Sub. mg /1 Impervious area rate accuniulation. 2 Pervious area rate accumulation. Subsurface concentration. 2.7. Z.7. 274: 6,075 6,,075 ,..° 2 7 0 60.8 Go.B` 67.5. .003 -.0047 .003--.0047 .01 ' .0026 -.025 • .0026 -.025 .005 -0.1 .0014 -.014 .0015 -0.2 .15 -1.0 .00023-.002 003 -.07 0.2 0.135 . 0.135 -0.675 0014 0017 .27 ..027 :.003 135 Adapted from RIBCO Streams; 1973.. Parameter Terrip.0 Cond. umho /cm ',Turbidity, JTU DO, mg /I FOOD, mg /I COD, mg /I Hexane Ext., mg /I Chloride, mg /I Sulfate, mg /I Organic N, mg /I Ammonia, N mg /I" Nitrate N, rn.g /I Nitrate N, trig/1 Hydrolyzable P, Ortho P, mg /I Copper m{g /1 'Lead, mg/1 Iron, 'mg /I' (Mercury, mg /1 Chromium, mg /I Cadmium, mg /i Zinc, mg /I Sett. Solids, mg /I Susp. Solids, mg /I TDS, my /I 134 Total.Coliform Org. /100 misc.' 28000 Fecal Coli form Ory. /100 rills° 3600 URBAN RUNOFF CHARACTERISTICS Table 6 Mean Concentrations in Urban Runoffs View View South South Lake Ridge 1 Ridge 2 Seattle Center Hills 13.1 125 30 8.6 30 05 12 7.7 17 2.6 0.32 0.11 0.67 0.45 0.12 0.040 0.44 2.4 0.0003 0.025 0.005 0.18 51 84 85 12.9 136 37 8.9 30 97 16 12 18 3.5 0.48 0.12 0.72 0.40 0.12 0.056 0.32 2.0 0.0004 0.009 0.004 0. 1'2 - See Appendix C b - Based on effluent concentrations normally expected from Secondary Treatment, modified concentrations measured at Renton STP for 1971. 112 125 26000 1200 14.8 134 47 8.5 19 95 14 12.2 26.1 1.7 0.32 0.06 0.83 0.24 0.08 0.10 0.25 2.1 0.0004 0.010 0.005 0.43 60 80 170 4200 30 High - Lands Secondary. Effluent from'' Municipal Sewage Treatment 13.3. ' 14.6 10.7 99 51 122 18.7 15 22 9.5 9.6 94 ' 151 8.5' ;',`8.0 70 , 68 '' • 57 11 7.3 '. 8.5 6.6 - 5.3 7.5 18 7 18 1.4 1.4 1.4 0.32.' 0.19` 0.09 0.04 0.03 0.02. 0.64 0.51 `'0.76 0.17 0.24 0.35'. 0.05 0.12 0.10 0.081 0.076 0.12 0.40 . 0.27 - 0.03 0.75 0.39 0.44 0.0008 ' . 0.0003 0.0008 0.074 0.010 0.010 0.004 0.004 0.004 0.24 0,082 0.068 40 , 40 03 73 54 08 89 72 -101 1600 37000 ' 1 600 370 1400 370 0.07 -'0.50 0.01 0.02 -0.15 0.15 0.20-040 c - Median to reflect higher Table 7 URrf!,N RUNCFF CHAt CTCRl`T1CS EOUTiC3:'1rLR Me;vn Concentration - P4 amotr:r 1'r3, 1 4 Mnr 1 0 Mar 1G Juno 6 hu ' 16 'c• t 19 Monti Temp. Crr 6,2 8.6 9.9 18.4 10.3 10.2 [,11 6.4 6.9 7.6 7.0 6.3 6.2 Cond. umho /cm 148 9.4 127 146 110 42 99 Turbidity, .7':'J 15 21 8.6 17.9 33.5 116 18.7 Do, mg /1" 10.7 11.2 10,2 8.4 7.8: 8,8 9,5 1300 , mg /1 4.7 4,4 11.6 10.6 36 21 15 COD, rq /1 78 48 59 79 107 ' 46 70 Hexane Lxt., m.g /1 17 14 7.9 6.2 11 9.2 11 Chloride, mg /1 7.2 1.3 13,7 3.5 12.4 1.2 6.6 Sulfate, rr,g /1 33 3.8 24 16 20 10 113 Organic 11, mg /1 0.12 0.86 1.1 1.3 .3.7. 1.3 1.4 Ammonia N, mg /1 0,34 0.09 0.22 0;21 0.81 0.27 0.32 Nitrite 17, mg /1 0.05 0.02 0.04 0.03 0.05 0.04 Nitrate 11, mg /1 0.48 0.31 0.58 '0.54 1,57 0.39 31yf1roIy2,,h1.e P, mg /1 0.20 0.13 0.09 0.19 0,29 0.10 Ort3o 0, mg /1 0.03 0.03 0.01 0.07 ,0.11 0.04 Copper, mg /1 0.016 0.015 0.085 0.032 0.030 0.26 Lead, mg /1 0.05 0,12 0.61 0.30 1.01 0.30 Iron, 00 /1 0.38 0.08 1.14 0.85 1.65 0.41' llercur-y, mg /1 0.0001 0.0019 0.0006 0.0005 Chromium, rag /1 0.015 0.010 0.010 0.092 0.31 0.005 0.074 Cadmium, mg /1 0.000 0.004 0.005 0.004 0.005 0.004' 0.004 2inc, m9/1 0,000 0,042 0.37 0.20 0.58 0:27 0,24 Lett, Colidn, mg /1 31 40 10 64 66 22 13.3 0ucp. Solids, mg /1 67 78 33 133 T03, mg /1 118 12 170 1 64 Total Coliform 1200 490 1900 Org /100 rtla n Fecal Coliforn Org /100 mlc Medians 110 370 -81- Hydrological and Water Quality Impacts Summary and Mitigating Measures (coned) A number of solutions to the water quality problems experienced in the Green River have been suggested in the RIBCO Water Quality Manage- ment Study, Part II, Urban Drainage Technical Report, December, 1974. One approach suggested to reduce stream concentrations during storms is the off stream holding -pond or tank approach. Another suggestion was to provide shading to the river in order to reduce . the amount of solar radiation recieved over a given area and thus to reduce problematical high temperatures. Surface run -off heat input to the river as a result of the proposed paved surfeces of the site could be partially mit- igated by undertaking a planting scheme for along the river levee. Such action is anticipated as part of the landscape planning for this project. In order to minimize hydrocarbons and suspended solids from entering the storm sewer system, separators or skimmers could be placed at the connection point. Lowering the water table, as a result of directing drainage into the sewer system could be minimized by the implementation of various design and engineering techniques. For example, drainage from impervious surfaces, could be accomplished by use of roof retention ponds to collect and store drainage to be released gradually into the water table through such systems as french drains. 'However, .,to effectively reverse the trend of lowering the table, such measures would have to be widely utilized in developments throughout the entire Green River Valley. AIR QUALITY Existing Air Quality Sulfur dioxide measurements were made in an area southwest of the project site on August 2 and 3, 1973. The 24 hour average was .038 ppm 502. This result is in general agreement with the values obtained by the Puget Sound Air Pollution Control Agency (PSAPCA) at Andover Park (Table 8) . Data obtained from these nearby areas suggest that . sulfur dioxide levels at the project site are likely to be well within standard allowable values given by PSAPCA (see Table 8) . Suspended particulates values are given in Table 9. A summary of motor vehicle related contaminants recorded at the nearest Department of Ecology Monitoring Station is presented in Table 10.;,; Although such data is too remote for a precise analysis of impact, it does give some indication of conditions within the airshed. The air quality standards for the other pollutants reulting from motor vehicles (hydocarbons and photochemical oxidants) were not projected to be exceeded in 1975, the Congressional deadline for meeting the ambient air quality standards. 1975 data is not yet available. The number of days the 8 hour carbon monoxide standard: would be exceeded was projected to drop in Seattle from 107 days in 1972 to 88 days in 1975. The maximum 8 hour concentration will be between 16 and 17 parts per million on these days. The subject site is influenced by both stationary sources of pollutants, the Seattle;Industrial area; and auto related sources such as the nearby free- ways. Particularly, peak hour traffic at the junction of Interstates 5 and 405, and at the Southcenter Mall to the west of the subject site, as well as Longacres Racetrack to the east of the site, constitute continued sources of vehicular pollutants. Sulfur Dioxide Lppm') July Dec. Jan. Feb: Mar, a 1974 Standard. 1972 1972 1973 1973 1973 year Value Monthly mean .004 .002. .002 .005 .006 .003 .02 annual mean Daily maximum .04 .01 .01 .02 .02 .02 .10 daily average Hourly maximum .24 .08 .08 .11 .11 .17 . .40 hourly average Table 8: Sulfur dioxide data obtained by the Puget Sound Air Pollution Control Agency at the Andover. Park Monitoring Station. Table 9 Suspended Particulate Annual Geometric Mean: 49/m3 1974 1973 1972 1971 Standard Seattle Center 45 36 45 44 Renton 43 42 44 43 60 McMicken Heights 35 35 42 60. 60 Impacts on Atmospheric Conditions The concentration of suspended particulates can be expected to tempor- arily increase during the construction phase of the proposed project. All temporary construction phases are subject to a degree of control by the contractors, in terms of dust and noise. The greatest contribution to the existing level of air contaminants will result from vehicular pollutants associated with mobile sources in and around the subject site. Although mitigating measures are not feasible within the scope of the proposed project, automobile pollutant concentrations are expected to decrease as emission control regulations become effective, even with the projected increase in'traffice volume associated with the proposed project. A detailed analysis of automobile pollutant concentrations resulting from traffic on and around the site by evaluation of indirect sources was not undertaken at this time. EPA parking management permit regulations requiring this evaluation were rescinded in 1974. TABLE 10 - AIR CONTAMINANTS RESULTING. FROM MOTOR VEHICLES AS RECORDED BY THE DEPARTMENT OF ECOLOGY - MONITORING STATION IN THE DUWAMISH -.:--LOCATED ON 6770 EAST .MARGINAL WAY Carbon Monoxide (CO) PPM Hydrocarbons PPM ' - Oxidant Parts Per Pundr,,d-Million Average Maximum Minimum - Average . Maximum Minimum - Average Maximum Min;mum 1972 : June 1. . 4 . 0 2 3 2 1 4 n v - • July - • ' 1 -14 — 0 2 .,.4 ....,... .. . 1 2 13 0 Aug. . 1 . • 7- • . ' 0 2 5 1 1- 4 0 .... • Sept. 8 - O. 3 6 •1 1 5 u -, Oct. 3 10 . 0 3 7 2 1 4 0 Nov. 3 15 0- 2 6 1 1 4 0 Dec. 7 --- 23 0 . 2 6 1 1 3 0 1973 Jan. Feb. 3 March: April May - June 2 2 L 21 0 2 7 2 12 0 2 7 2 9 0 2 5 2 6 0 2 5 2 8 0 2 4 2 10 0 2 4 1 0- 0 4 3 2 0 0 0 0 5 0 2 0 ugm/m3 PPM :-. Ambient air 8-Hour quality Average 10 9 - Standards not to be 1-Hour exceeded more than Average 40 35 nce per. yea r 3-Hour Average ugm/m3 PPM ugm/m3 PPM 1-Hour 160 0.24 Average 160 0.08