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HomeMy WebLinkAboutSEPA EPIC-52-91 - METRO - INTERURBAN SEWER SYSTEM IMPROVEMENTSINTERURBAN SEWER SYSTEM IMPROVEMENTS THROUGH FOSTER GOLF LINKS, FORT DENT PARK & ALONG INTERURBAN AVE. EPIC 52 -91 • METRCil /, Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104 -1598 DETERMINATION OF NONSIGNIFICANCE (DNS) INTERURBAN SERVICE AREA SEWER IMPROVEMENTS 61LF,[i \VN OCT 09 1991 CITY OF TUScvvli.A PLANNING DEPT. 0 PROJECT DESCRIPTION: Metro proposes to make improvements to the existing sewage conveyance system which include constructing a new pumping station located off Interurban Avenue South at the south end of Foster Golf Links; constructing a new gravity sewer line to the new pumping station; and constructing a new forcemain from the new pumping station site to the Metro treatment plant at Renton. The new gravity sewer would be a 26 inch to 36 inch pipeline replacing the existing Tukwila Trunk Sewer from the Val Vue connection approximately 5,050 feet south parallel to Interurban Avenue South. The new forcemain would be a 20 inch pipeline constructed along one of two alternative routes to the Metro treatment plant at Renton. One forcemain alternative travels east through Foster Golf Links down railroad right of way and through Fort Dent Park. The other forcemain route travels south along Interurban Avenue and through Fort Dent Park. PROPONENT: Municipality of Metropolitan Seattle (METRO) LOCATION OF PROPOSAL, INCLUDING STREET ADDRESS, IF ANY: The project is located in King County, Washington, section 14, 15, 23, and 24, , Range 4 East, Township 23 North. This area encompasses part of the City of Tukwila from the 41st Avenue Bridge along Interurban Avenue South to Fort Dent Park and an adjacent portion of the City of Renton. LEAD AGENCY: MUNICIPALITY OF METROPOLITAN SEATTLE (METRO) The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under WAC 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. There is no comment period for this DNS. X This DNS is issued under 197 -11- 340 (2); the lead agency will not act on this proposal for 17 days from the date below. Comments must be submitted by September 5, 1991. DATE: August 19, 1991 RESPONSIBLE OFFICIAL: Gregory M. Bush POSITION /TITLE: Manager /Environmental Compliance and Right of Way Division TELEPHONE NUMBER: (206) 684 -1164. ADDRESS: 821 Second Avenue, Seattle, Washington 98104 SIGNATURE: ' You may appeal this Executive Director, Washington, 98104. factual objections. determination to Richard K. Sandaas, at Metro- 821 Second Avenue, Seattle, You should be prepared to make specific Contact Ellis McCoy at 684 -1731. • • giPlc-,-52-9 ktcEift-#-5eyoo ENVIRONMENTAL CHECKLIST INTERURBAN SEWER SYSTEM IMPROVEMENTS A. BACKGROUND ___ AP I.� 1 I \q 5 1. Name of the proposed project: [OCT 0 9 1993 D CITY OF TUKVVILA 2. Name of Applicant: PLANNING DEPT Municipality of Metropolitan Seattle (Metro) 3. Address and telephone number of applicant and person: Municipality of Metropolitan Seattle (Metro) 821 Second Avenue MS 120 Seattle, WA 98104 Contact: Ellis McCoy (206) 684 -1731 contact 4. Date checklist prepared: August 15, 1991 5. Agency requesting checklist: Municipality of Metropolitan Seattle (Metro) 6. Proposed timing or schedule (including phasing, if applicable): Construction will begin after the appropriate permits are obtained. Construction is expected to begin during the summer of 1992, and is expected to last approximately 18 months. 7. Plans for future additions, expansion, or further activity related to or connected with this proposal: There are no plans for future additions or expansion of facilities to be constructed as part of this project. Construction of Interurban Sewer System improvements may coincide with construction associated with the expansion of the Metro treatment plant at Renton. 1 8. Environmental information that has been prepared, or will be prepared, directly related to this project: Environmental information related to this project will be included in the Interurban Sewer System Predesign Report being prepared' concurrently with this Environmental Checklist by HDR Engineering, Inc. Additional environmental information relating to the project can be found in the following documents: - Environmental Analysis - Task 390, Alki Transfer - CSO Control Facilities Proiect (Municipality of Metropolitan Seattle, 1990), - Facilities Plan for Alki Transfer Facilities Project (Municipality of Seattle, 1990), - Predesign Report for Alki Transfer Facilities Project (Municipality of Seattle, 1990), - CSO Control Metropolitan - CSO Control Metropolitan - Draft Supplemental Environmental Impact Statement: Metro Treatment Plant at Renton - Phase III Enlargement (Municipality of Metropolitan Seattle, 1991), and - Draft Environmental Impact Statement for Rabanco / Black River Waste Recovery Center (Rabanco Regional Landfill Company, 1991). 9. Applications that are pending for governmental approvals or other proposals directly affecting the property covered by the proposal: The City of Tukwila intends to improve sections of Interurban Avenue S. from near 42nd Avenue S. to 52nd Avenue S. This will include: bridge removal; widening and paving; installation of curbs, gutters, sidewalks, landscaping, light poles, signals; stormwater collection, treatment and discharge; and installation of a storm sewer trunkline. A Mitigated Determination of Non - Significance (DNS) was issued July 20, 1991. A small portion of one of the forcemain alternatives (See 11. below.) will cross the site of the proposed Rabanco / Black River Waste Recovery Center, just east of Foster Golf Links and the BNSF Burlington Northern / Union Pacific rail lines. The proponent is in the process of obtaining permits for the project from the City of Renton and other agencies with jurisdiction. 2 Both forcemain alternatives (A and B) will enter the west side of the Metro treatment plant at Renton off Monster Road S.W. where it will continue to a transition structure on the treatment plant site. Metro is in the process of obtaining permits for expansion of the treatment plant from the City of Renton and other agencies with jurisdiction. 10. .List of governmental approvals or permits that will be needed for the proposal: The following approvals and permits are anticipated to be needed for the proposal: Federal Army Corps of Engineers Section 404 Permit Section 10 Permit State of Washington Department of Transportation Highway Crossing Permit Departments of Fisheries and Wildlife Hydraulic Project Approval Department of Natural Resources Easement for Construction Permanent Pipeline Easement Puget Sound Air Pollution Control Agency Notice of Construction and Application for Approval City of Tukwila Board of Architectural Review -7 Excavation Permit Shoreline Substantial Development Permit Street Use Permit Utility Permit Building Permit Grade /Fill Permit Right of Way Construction Permit Necessary property rights for pump station and facilities 3 • • City of Renton Shoreline Substantial Development Permit . Right of Way Construction Permit Grading Permit King County_ Easement for Construction Grading Permit Seattle -King County Health Department On -Site Sewage Disposal System Permit Other Burlington Northern Railroad /Union Pacific Railroad Pipeline Crossing Permit Permanent Pipeline Easement Puget Western /City Light Easement for Construction Permanent Pipeline Easement 11. Brief, complete description of the proposal, including the proposed uses and the size of the project and site: The proposed Interurban Sewer System improvements include the following three elements: 1) Construction of a new Tukwila Trunk Sewer from near the Val Vue Connection to the new Interurban Pumping Station at the south end of Foster Golf Links; 2) Construction of a new Interurban Pumping Station near the south end of Foster Golf Links; and 3) Construction of a new forcemain from the proposed pumping station site to the Metro treatment plant at Renton. These improvements are shown in Figures 1 and 2. The entire project is expected to take 18 months to construct. The pumping station itself will take the full 18 months. Various segments of the Tukwila Trunk and forcemain will take shorter periods of time; construction of some elements may occur concurrently. 4 I,VVrsJL /1,2, . fr<j9, FOOTBRIDGE N BLACK RIVER FIGURE 1 Proposed Tukwila Trunk and ANew Interurban Pumping Station E is VAL VUE CONNE S. 124T STEXIST \4166, EXI. ETS P FM ( 6 ") • SCA E N F PROP6SED TU- ILA TR • 4 EX S ING URBAN PUM?ING STATI I N ‘g\ 900 r \\N, FOSTER GOLF COURSE PROPOS • INTERIJR PUMPIVG STATION FOOTBRI[)GL _ r--vicT FIGURE 2 Proposed Interurban Pumping Station and Alternative Forcemain Alignments • • Tukwila Trunk Sewer. The new Tukwila Trunk will begin at the existing manhole T -14 (5A), about 50 feet south of the Val Vue Connection near 42nd Avenue S. and Interurban Avenue S. From this point, the new trunk will continue south under the existing drainage swale in the old Puget Sound Electric Railway right -of -way (now owned by Seattle City Light). This right -of -way parallels Interurban Avenue S. and is continuous to near S. 140th Street. The new Tukwila Trunk will be installed adjacent to the existing Renton ETS pipeline which is located in the west side of this right -of -way. The first 1,650 feet of the new trunk will be a 24 -inch diameter concrete pipe installed at a depth of between 15 and 22 feet below grade. At the southern entrance to Gateway Corporate Center, the diameter of the trunk will increase to 36 inches. The trunk will continue south for approximately 1,000 feet to the Interstate -5 (I -5) right - of -way. Construction of this section of the Tukwila Trunk (Val Vue Connection to I -5) is expected to take about 3 months. Installation of the trunk sewer will require a trench about 10 feet in width supported by sheetpiles. It is expected that continuous dewatering will be required. It is estimated that 20 to 50 feet of pipe can be installed each working day. As pipe sections are installed, sheetpiles will be pulled and the trench will be backfilled. About 100 feet of trench will be open at any given time. The construction area will be about 1,000 feet by 60 feet along the alignment and will be used for construction purposes (e.g. vehicles, equipment, materials storage, parking). The width of the corridor will narrow to 30 feet or less as it crosses local streets and access points for local businesses. The I -5 crossing will be accomplished by jacking or tunneling a 660 foot, 60 -inch diameter casing pipe under the existing structure and approach ramps. The 36 -inch concrete trunk line will be installed within the casing pipe. A jacking pit will be constructed south of I -5 near the entrance to Grantree Furniture. This pit will be about 20 feet wide by 50 feet long and 25 feet deep. Construction is expected to last 6 to 8 weeks. This section will also require dewatering. South of I -5, the 36 -inch trunk will continue in the City Light right -of -way for approximately 2,400 feet to the site of the new Interurban Pumping Station. Just south of I -5, the new trunk sewer will be within 100 feet of 5 the Duwamish River for a distance of approximately 500 feet. Construction methods will be similar to those described above. Construction of this section of the trunk is expected to last about 3 months. A new 12 -inch pipeline will be constructed across Interurban Avenue S. in order to collect flows now served by the existing pumping station. The existing station will be removed to about three feet below grade, backfilled and the site restored to a condition compatible with adjacent multi - family uses (i.e. landscaped parking areas). Demolition of the existing station is expected to take about one month and will occur once other elements of the new Interurban Sewer System become operational. Interurban Pumping Station. The new Interurban Pumping Station will be constructed adjacent to Interurban Avenue S. near the south end of Foster Golf Links.. This location is just south of the golf course maintenance road about 1,000 feet south of the existing pump station. (The proximity of the existing pumping station to multi- family residences and the potential for odorous emissions is one of the reasons for relocating the pumping station.) The new pumping station will consist of an above grade structure approximately 28 X 44 feet, averaging 14 feet high (maximum height will be 16 feet). Below grade, the structure will be about 40 X 44 feet. The pumping station site will total approximately 13,000 square feet. The new pumping station will be designed to convey an ultimate peak flow of 10.0 mgd. Construction is expected to last about 18 months. Forcemain. There are two alternative routes for the 20- inch forcemain from the new Interurban Pumping Station to the Metro treatment plant at Renton. Forcemain Alternative A runs east from the new pumping station, parallel with the ETS line, through Foster Golf Links, crossing the Duwamish River using the golf course footbridge and then under the Burlington Northern / Union Pacific rail lines. The forcemain will then continue parallel to the Renton ETS line, southeast to the Black River. The forcemain will be jacked or tunneled under the Black River just east of the rail lines. At this point, the forcemain will again cross the rail lines to Fort Dent Park. It will be be trenched under the Black River railroad trestles on the south side of the channel. Once in Fort Dent Park, the forcemain will run southeast along the west side of the railroad 6 embankment to.the southeast corner of the park, where it will be jacked under the rail lines. Once on the east side of the rail lines, the forcemain will again parallel the.ETS pipeline, following the railroad access road to Metro's treatment plant at Renton. The forcemain will cross Monster Road S.W. and enter the treatment plant near the main entrance gate. Total length of the forcemain will be about 7,800 feet. Forcemain Alternative B involves running the 20 -inch forcemain southeast from the new Interurban Pumping Station along Interurban Avenue S. for approximately 3,800 feet to a location across the river from the southwest end of Fort Dent Park. This section of the forcemain is to be installed in public right -of -way obtained by the City of Tukwila from adjacent property owners in trade for vacating Maule Avenue, a 20 -foot wide right -of -way which bisects the' properties adjacent to Interurban Avenue S. The forcemain will cross the Duwamish (Green) River to Fort Dent Park via a new pipebridge or by tunneling under the river. Although design is not yet complete, it is likely that the bridge crossing will require footings on each bank. Construction will require use of some floating equipment although most of the work can be accomplished using shore -based equipment. The tunneling option will require staging areas and moderately deep tunneling pits on each side of the river. After crossing the Duwamish River, the forcemain route will run in an easterly direction for about 1,750 feet, crossing multi - purpose sports fields, parking areas and the principal park access road. It will be jacked under the Burlington Northern / Union Pacific rail lines at the southeast corner of the park near the soccer field. From this point, the forcemain will follow the ETS right -of -way along the railroad access road, crossing Monster Road S.W. into the treatment plant near the main access gate. Total length of forcemain alignment B will be similar to alignment A, about 7,800 feet. For both A and B alternatives, the 20 -inch forcemain will be ductile . iron, steel or concrete cylinder pipe, installed in an open cut trench about 6 feet deep and 15 to 20 feet wide. It is unlikely that shoring of the trench will be necessary. Because of the shallow depth of the trench, dewatering is not anticipated. It is • • estimated that between 100 and 300 feet of pipe can be installed each working day. Construction is expected to last about 4 months. Jacking pits will be required for railroad crossings on each side of the railroad embankments. Because of the shallow forcemain depth and the elevated railroad embankment, these pits are expected to be shallow and will not require substantial excavation. Jacking pits for the Black River crossing ( Forcemain Alternative A) will be somewhat deeper because of the low elevation of the channel. For both forcemain alternatives, a below grade chlorine injection facility will be installed adjacent .to the treatment plant entrance road in order to control odorous gases. Following chlorine injection, the forcemain will discharge into a new transition structure which will strip hydrogen sulfide from the wastewater flow. All but a small portion of the transition structure will be below grade. A new 30 -inch diameter gravity line will convey the flow from the transition structure to the plant's influent control structure. 12. Location of the proposal, including street address, if any, and section, township, and range; legal description; site plan; vicinity map; and topographical map, if reasonably available: The project is located in King County, Washington, sections 14, 15, 23, and 24, Range 4 East, Township 23 North. Figures 1 and 2 show the location of the Tukwila Trunk, the new Interurban Pumping Station and the two alternative forcemain routes (A and B) to the Metro treatment plant at Renton. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site: The project area is located in the central portion of the Puget Sound Lowland. Various soils and bedrock have been classified in the project area and are generally described below. 8 Fill Most of the lower Duwamish River Valley has been extensively modified by filling and dredging activities over the last century. Almost all surficial soils in developed areas have been disturbed to some extent by road grading and filling of topographic depressions to provide level structures. Fills in the Duwamish Valley commonly consist of loose or loose to medium dense, fine to medium sand and silty sand placed hydraulically over areas that were previously estuarine mudflats or low areas along the Duwamish River. Fills, however can range widely. Other fills have been placed to support specific structures. These include the majority of the Burlington Northern / Union Pacific Railroad tracks south of I- 5 and many of the industrial and warehouse buildings in the Duwamish Valley. Alluvium /Estuarine Deposits Alluvium is present in the small stream channels and along the Duwamish River. These deposits are usually thin and localized and range in gradation from silt to sand and gravel. Duwamish Valley alluvium and estuarine soils consist predominately of fine and fine to medium loose to medium dense sand, silty sand and silt. In some areas finer - grained or organic alluvium/ estuarine soils have been observed. These deposits include beds of clay, clayey silt, organic silt and peat. In some cases the finer - grained soils are very loose to loose or very soft to soft. The thickness of the alluvium /estuarine deposits is variable, but generally thickens toward the mouth of the Duwamish River. Vashon Till Till is an unsorted mixture of clay, silt, sand, and gravel deposited directly beneath a glacier and densely compacted by the weight of the overriding ice. Within the project area the till is usually classified as a silty sand, sandy silt, or clayey silt. Occasionally large boulders (up to approximately 10 -feet in diameter) are found within the till. • • Bedrock Bedrock outcrops appear along the slopes east of the Duwamish River. These outcrops include rocks of the Blakely Formation and older Eocene age sedimentary rocks of the Tukwila and Renton Formations. The Blakely Formation is an interbedded sequence of marine siltstone, sandstone, shale and conglomerate. The Tukwila and Renton Formations are typically deeply weathered and soft near the ground surface. b. What is the steepest slope on the site (approximate percent slope)? Most of the area along the pipeline alignments and in the vicinity of the new pumping station site have slopes of between 0 and 5 per cent. Slopes to 30 percent occur at sites of engineered fill (e.g. I -5 and railroad embankments) and along the shoreline of the river. c. What general types of soils are found on the site (for example clay, sand, gravel, peat, muck)? Specify the classification of agricultural soils and note any prime farmland. Tukwila Trunk In the Preliminary Geotechnical Study, Tukwila Trunk Sewer Rehabilitation Project, Tukwila, Washington (Golder Associates, 1990), four strata were identified in this portion of the study area. These four strata generally correspond to those described in B.1.a. above. It can be expected that all of the above mentioned soil types will be encountered during construction of the Tukwila Trunk Sewer. The ground water table appears to vary between elevation 4 to 12 feet along the alignment (Golder Associates, 1990). Based on excavations associated with the Renton ETS line, contaminated soils are not anticipated. Interurban Pumping Station The soils at the new Interurban Pumping Station site are likely to be very similar to those described above. Some or all of these soils may be encountered during construction, depending upon the extent of the excavation. 10 • Forcemain The soils encountered during construction of the forcemain are likely to be similar to the soils mentioned above in varying depths of thickness. Fills near the Burlington Northern / Union Pacific Railroad tracks are likely to be well compacted sandy gravel. d. Are there any surface indications or a history of unstable soils in the immediate vicinity? If so, describe. The topography of the pumping station site and pipeline corridors is relatively flat and not subject to unstable soil conditions. At the same time, much of the area consists of fill with a relatively high groundwater table. These conditions require special construction techniques (e.g. dewatering and tight- sheeting). e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate the source of the fill. For the Tukwila Trunk, an estimated 24,000 cubic yards will have to be excavated. About 17,000 cubic yards of bedding and fill material will have to be imported, probably from local gravel pits. About 17,000 cubic yards of material will have to be hauled away for disposal. At the site of the proposed Interurban. Pumping Station, an estimated 2,800 cubic yards of material will be excavated. Imported fill requirements will be about 1,400 cubic yards; between 1,500 and 1,600 cubic yards of material will be hauled away for disposal. For the forcemain (both alternatives), about 10,000 cubic yards will have to be excavated. There will be about 3,500 cubic yards of imported bedding and fill material; about 3,500 cubic yards of material will have to be hauled away for disposal. All material shall be disposed of at an approved disposal site. f. Could erosion occur as a result of clearing, construction, or use? . Construction of the Tukwila Trunk, new pumping station and forcemain will require excavation by means of conventional equipment (e.g. hydraulic backhoes, front -end loaders). Temporary increases in surface runoff and soil erosion may occur as a result of removal of vegetation, and loosening, exposure and stockpiling of soils during construction. About what percent of the site will be covered with impervious surfaces after project construction (for example buildings or asphalt)? Following installation of the new Tukwila Trunk and the forcemain to the Metro treatment plant at Renton, disturbed areas will be restored to their original condition (e.g. paved, landscaped, undeveloped). In these areas, there should be no net change in impervious surfaces. At the site of the new pumping station, it is estimated that there will be an additional 9,000 square feet of impervious surface, consisting of the structure and accessory parking areas. h. Describe the proposed measures to reduce or control • erosion, or other impacts to the earth, if any. Proposed measures to reduce or control the project's short -term construction- related impacts on earth and soils may include the following: - designing dewatering systems to minimize silt and turbidity in discharge; - minimizing the size of disturbed areas along the pipeline corridors and at the new pumping station site; - employing erosion control techniques such as silt fences, hay bales, sedimentation ponds, etc.; - covering stockpiled soils with sheeting to minimize erosion potential; - minimizing excavation and other earthwork within shoreline zones; 12 - restoring disturbed areas (i.e. replanting, repaving) as soon as practical after construction has been completed; - installation of the forcemain on the golf course will occur within the February 1 - March 15 period in order to enhance resodding success and related site restoration efforts; - compliance with City of Tukwila and City of Renton erosion control requirements; and - continuous supervision of construction activities by Metro inspectors and enforcement of Metro's erosion control - related specifications. 2. Air a. What types of emissions to the air would result from the proposal (e.g. dust, automobile, odors, indust rial, wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities, if known. Over the 18 month construction period, exhaust from construction vehicles, equipment and haul trucks will be the primary sources of air emissions. This will consist primarily of carbon monoxide and hydrocarbons. Construction activities will also generate minor amounts of dust and particulates. Over the long term, there is potential for odor generation in the Tukwila Trunk, in the wetwell at the new pumping station, and in the forcemain. Hydrogen sulfide and other gases can be generated in wastewater facilities under low oxygen or anoxic conditions. This is of particular concern when the organic content of wastewater is relatively high. For this project, odor generation is of concern at the pumping station wetwell, where turbulence releases gases to the atmosphere. Hydrogen sulfide and other gases also tend to accumulate along the forcemain, a low oxygen environment. At high points along the forcemain, these gases tend to accumulate and have the potential for restricting flow. In addition, turbulence at the forcemain discharge (i.e. transition from a pressure line to a gravity line) causes release of accumulated gases to the atmosphere. 13 b. Are there any off -site sources of emissions or odors that may affect your proposal? If so, generally describe. The discharge of the rendering plant to the Interurban collection and conveyance system creates high odor potential at the existing Interurban Pumping Station because of the high organic content of the waste flow. c. Describe proposed measures to reduce or control emissions or other impacts to air, if any. A number of measures can be employed to reduce or control construction - related impacts on air quality. These include: - careful adherence to traffic control plans in order to avoid extended slowdowns of local traffic; - avoidance of prolonged idling of construction vehicles and equipment; - requiring contractors to maintain vehicles and equipment in good operating condition; - use of electrically - powered equipment where practical; - controlling dust by spraying exposed soils during dry seasons as needed; and - periodic cleaning of haul trucks and roadways in the immediate vicinity of construction sites to reduce generation of dust. Over the long -term, a number of odor control measures will be implemented to reduce odor generation at the new pumping station and along the forcemain route. In order station, installed exchanges from the activated to control odor within the pumping separate ventilation systems will be for wetwell and drywell (12 and 6 air per hour, respectively). Exhaust air wetwell will be scrubbed using an carbon unit for odor control. Chemical storage and feeding facilities will be provided for odor and corrosion control in the 14 • • forcemain. Chemicals may include caustic soda, sodium hypochlorite and iron salts. There are three potential high points along the alternative forcemain alignments: the golf course footbridge (Alternative A), the Black River pipebridge (Alternative A) and the Duwamish River pipebridge (Alternative B). A gas release valve will be needed to prevent gas pockets from forming at these locations. Gases from the golf course footbridge (Alternative A) will be directed back to the pumping station for scrubbing. At the Black River pipebridge (Alternative A) and Duwamish River pipebridge (Alternative B), gases will be drawn to the shoreline for scrubbing with a small, below -grade activated carbon unit and a small above -grade vent. At the Metro treatment plant at Renton, facilities will be provided to control the release of odorous gases which have accumulated in the forcemain. A chlorine injection point will be provided adjacent to the north plant entrance road. This facility will be located as far upstream as possible from the forcemain discharge (though still on the treatment plant site), in order to allow the maximum amount of time for mixing and the destruction of hydrogen sulfide. A new transition structure will be installed to create turbulence and strip hydrogen sulfide from the wastewater flow. The gases generated in the transition structure will be collected and passed through an activated carbon scrubber before being released to the atmosphere. 3. Water a. Surface: 1. Is there any surface water body on or in the immediate vicinity of the site (including year -round and seasonal streams, saltwater, lakes, ponds, and wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. The principal surface water body located in the vicinity of the project is the Duwamish (Green) River. The project involves potential bridge crossings of the river at the existing 15 • • Foster Golf Links footbridge (Forcemain Alternative A) and a new pipebridge at the southwest corner of Fort Dent Park (Forcemain Alternative B). In addition, construction activities (Tukwila Trunk) will occur within 200 feet of the Duwamish River near the Val Vue Connection and just south of I -5. The confluence of the Black River Channel and the Duwamish River is located at the northeast end of Fort Dent Park. Forcemain Alternative A crosses over the Black River with a new pipebridge just east of the rail lines within the existing ETS pipeline right -of -way. There is a large drainage ditch along portions of the east side of Interurban Avenue S. near the Gateway Park development and south of Foster Golf Links. Proposed Tukwila Trunk alignments will be located parallel to and east of this drainage facility. The City of Tukwila maintains a large drainage facility near the Val Vue Connection. It is a large open ditch / ravine which directs runoff from near SR 599 under Interurban Avenue S. to the Duwamish River. The new Tukwila Trunk will cross under this ditch near the location of the existing Tukwila Trunk line. Salmon may utilize the extreme lower portions of this drainage. There is a large pond / retention basin on the east side of Fort Dent Park near the base of the railroad embankment. Forcemain Alternative A will run between the pond and the railroad embankment. The City of Tukwila has established a 50 foot buffer requirement around the pond. A variance will have to be obtained from the city to construct within this buffer. 2. Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. The Interurban Sewer System Project will require construction within 200 feet of 16 • • surface waters in several locations, depending on which forcemain alternative is selected: a) the Tukwila Trunk just south of the Val Vue Connection (Duwamish River), b) the Tukwila Trunk just south of I -5 (Duwamish River), c) Forcemain Alternative A at the Foster Golf Links footbridge (Duwamish River), d) Forcemain Alternative A's new pipebridge crossing (Black River), and e) Forcemain Alternative B's river crossing near the southwest end of Fort Dent Park (Duwamish (Green) River). These locations are shown in Figures 1 and 2. Construction of the Tukwila Trunk in shoreline areas will involve open cut construction methods. The trunk will be installed at a depth of between 15 and 22 feet below grade. Tightsheeting of the trench and dewatering are likely to be required. It is expected that the 20 -inch forcemain can be hung from the existing golf course • footbridge using shore -based equipment. Impacts on the shoreline and riparian vegetation should be minimal if staging areas are set back from the river. Similarly, the new pipebridge crossing at the Black River will be accomplished using shore - based equipment. The new pipebridge at the southwest end of Fort Dent Park will be constructed principally with shore -based equipment with a smaller amount of floating equipment. Impacts to the shoreline and riparian vegetation can be minimized if staging areas are set back from the shoreline. Potential impacts will be further reduced if this crossing is accomplished by tunneling under the river. 17 • 3. Estimate the amount of fill and dredge material that could be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill materials. The new Tukwila Trunk will be constructed across the City of Tukwila drainage facility just south of the Val Vue Connection using open cut construction methods. Construction will occur during the dry season when flows in this facility are at a minimum. Existing soils will be excavated several feet below the bottom of the ditch / ravine and clean imported fill used for bedding material and backfill. It is estimated that 400 cubic yards of material will be excavated and 200 cubic yards of imported fill will be required for installation of the 24 -inch sewer at this location. The new pipebridge crossing of the Duwamish River near the southwest end of Fort Dent Park ( Forcemain Alternative B) may require a small amount of dredging and filling as part of bridge footings. The dredge and fill volumes will be determined following design work if this forcemain alternative is selected. No other filling or dredging from surface waters or wetland areas is anticipated. 4. Will the proposal require surface water withdrawals or diversion? Give general description, purpose, and approximate quantities, if known. Depending on season, the project may require temporary diversion of surface waters in the City of Tukwila drainage facility just south of the Val Vue Connection. Construction will be scheduled during dry weather conditions when flows are at a minimum. Any diversion is expected to last no more than several days. 5. Does the proposal lie within a loo -year flood plain? If so, note location on the site plan. A number of locations along the trunk and forcemain alignments lie within the 100 -year 18 • floodplain. See Figures 3 and 4 for specific locations. Forcemain Alternative B's new pipebridge crossing to Fort Dent Park will be designed to provide 6 feet of clearance above the 100 -year flood elevation. 6. Does the proposal involve discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. The project does not involve the discharge of waste materials to surface waters. b. Ground 1. Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. Dewatering will be required for installation of the Tukwila Trunk from the Val Vue Connection to the proposed pumping station at the south end of Foster Golf Links. Dewatering is also likely at the new pumping station site. Based on experience constructing the Renton ETS line, it appears that it is unlikely that groundwater will be contaminated, although there may be some petroleum hydrocarbons in the vicinity of the gas stations just north of I -5. Groundwater will be discharged to the sanitary sewer, to local storm drainage facilities or tight -lined to the Duwamish River depending on location, volumes and quality. Groundwater will be tested periodically over the course of construction to determine the appropriate method(s) of disposal. Discharge of dewatering volumes to the sanitary system will require a Metro Industrial Waste discharge approval. The Department of Ecology will have to approve discharge to the Duwamish River and /or tributaries to the river. No groundwater withdrawals will occur once construction has been completed. 19 L 1_,„„ som-- --I L- \\��: — �17aiir RM324 • • ■ 14 a 1 "L ZONE X 1-11 Figure 3. 100 -year Flood Zones Interurban North RM326 Footendye �J ZONE V/ APPROXIMATE SCALE IN FEET 'S 600 O co 6 C—t J \\, ZONE X ` ZONEyAO S\ 1 1431itj-Sr '1■Z 1:4 ite • 0 J.4' rflf 'eV Crtair-T-0110 -PL'Atr- ZONE X QUrri-r-4 ZONE AE REET- -SOUTH-T4 91-H- WEE ZONE X 11M33 • III NION WASIIWAIIU 1111 AI Nil NI MANI Figure 4. 100-year Flood Zones Interurban South CITY OF TUKWILA APPROXIMATE SCALE IN FEET 600 0 500 11-•••••-•-i 24 . ' • • • 2. Describe waste material that will be discharged into the ground from septic tanks or other sources, if any. Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) is expected to serve. High points in the forcemain at the Black River pipebridge crossing (Alternative A) and Duwamish (Green) River pipebridge crossing (Alternative B) will collect gas bubbles. These will be treated using an activated carbon scrubber. Any sewage associated with this gas will be discharged to local sewer lines or treated in a small drainfield. Wastewater volume is expected to be very low (several gallons per day). Discharge of sewage to a local drainfield will require an On -site Sewage Disposal System Permit from the Seattle -King County Health Department. c. Water Runoff (including storm water) 1. Describe the source of runoff (including storm water) and method of collection and disposal, if any (including quantities if known). Where will the this water flow? Will this water flow into other waters? If so, describe. During construction, runoff from construction sites has the potential for reaching local drainages, the Duwamish and Black Rivers and Fort Dent Pond. The relatively flat topography and the locations of much of the construction which will occur indicates that control of runoff can be accomplished with careful attention to standard construction practices. In the immediate vicinity of surface water bodies such as the Duwamish and Black Rivers and Fort Dent Pond, special methods for controlling runoff may be necessary to prevent turbid runoff from reaching these waters. The new pumping station is expected to add about 9,000 square feet of impervious surface to the area. This will slightly increase storm runoff and drainage in the immediate vicinity of the station, however, the impact on existing drainage facilities will be minor. 20 2. Could waste materials enter ground or surface waters? If so, generally describe. During construction, petroleum products, solvents, lubricants, etc. associated with construction vehicles and equipment have the potential for reaching surface and groundwater if contractors do not follow project specifications and standard construction practices. Once the system becomes operational, no waste materials are expected to reach ground or surface waters. d. Describe proposed measures to reduce or control surface, ground, and runoff water impacts, if any. One of the principal objectives of this project is to reduce combined sewer overflows to the Duwamish River by expanding the capacity of the Tukwila Trunk. This will result in improved water quality in the river, particularly in the vicinity of Interurban Avenue S. and 42nd Avenue S. Potentially adverse impacts on water quality associated with the trunk sewer, pumping station and forcemain are related to construction. The following methods can be used to reduce or control these impacts: - Minimizing the amount of area and vegetative cover disturbed by construction; Maintenance of stream and river bank integrity; - Limiting construction in sensitive areas (i.e. wetlands, stream crossings) to dry seasons to reduce potential for turbidity; - Use of sedimentation controls such as hay bales, rock filters, silt screens and fences, on -site sedimentation basins, and drainage swales; - Strict adherence to Metro guidelines for dewatering; periodic testing of groundwater quality; depending on volume and quality, groundwater will be directed to sanitary sewers or storm drains; if groundwater is contaminated, on- site treatment may be necessary; - As far as possible, construction vehicles and equipment will be stored away from surface waters; 21 • • contractors will be required to handle any petroleum products, lubricants, solvents, etc. in a responsible manner in accordance with generally - accepted construction practices; - Stockpiles of excavated material and /or imported bedding material will be stored away from surface waters and will be covered when not in use; - Disturbed sites will be restored with vegetation (preferably native) as soon as practical after construction has been completed; and - Use of pervious paving materials (e.g. "grasscrete ") where practical instead of asphalt or concrete. 4. Plants a. Types of vegetation found on site: Deciduous trees: alder, maple, cottonwood, willow, birch, various ornamentals Evergreen trees: douglas fir, pine, ornamentals Shrubs: various Grass: various, ornamental (golf course, park) Pasture: none Wet Soil Plants: see description below Water Plants: see description below Vegetation along the Tukwila Trunk corridor, the site for the new Interurban Pumping Station, and two alternative forcemain routes is described below. Tukwila Trunk. Just south of the. Val Vue Connection, there is a deep (20 feet) drainage which crosses Interurban Avenue S. and the City Light right -of -way, draining to the Duwamish River. Running water was observed in the lower portion of this drainage, an estimated 100 feet east of the existing Tukwila Trunk line. Vegetation observed included reed canarygrass and himalayan blackberry. Much of the proposed alignment follows the City Light right -of -way along Interurban Avenue S. 22 • • North of I -5, the eastern portion of the right -of- way has been landscaped with lawn and small ornamental trees. South of I -5 along the pedestrian / bicycle path, vegetation includes deciduous trees and grasses. There is also a large drainage ditch which runs about 20 feet east of Interurban Avenue S. and parallel to it. The ditch includes associated emergent /scrub -shrub wetland vegetation typical of the region. Just south of I -5, the Duwamish River flows close (100 feet) to Interurban Avenue S. The vegetative community adjacent to the river is dominated by deciduous trees and shrubs. The preferred pumping station site adjacent to Interurban Avenue S. just south of the golf course does not support any vegetation of significance. Vegetation on Foster Golf Links consists primarily of turf with a variety of both ornamental and native trees. Douglas fir is common throughout the course. On the east side of the rail lines, the forcemain corridor has been highly modified by industrial activities. Only limited native vegetation is present along the railroad embankments. The Black River supports a very limited amount of riparian vegetation (e.g. willows). From the northeast corner of the Fort Dent Park, Forcemain Alternative A will parallel the rail lines (west side) to the southeast corner of the park. For the most part, this area consists of large grassy areas with occasional deciduous (i.e. maples, birch) and evergreen (i.e. Douglas fir, pine) trees. The forcemain will run between the railroad embankment and the large pond along the eastern margin of the park. The eastern margin of the pond is located approximately 40 feet from the rail line embankment; the area contains a pedestrian gravel walkway and benches, and is landscaped with a number of birch trees (25 -30 feet in height). Forcemain Alternative B will run south from the new pumping station along Interurban Avenue S. to a location across the river from the south end of 23 • • Fort Dent Park. Vegetation along this alignment has been highly altered by commercial, industrial and transportation land uses and provides only limited habitat for wildlife. The proposed bridge crossing to Fort Dent Park will encounter a variety of riparian vegetation, including willows, alder, maple, and himalayan blackberry. Once in Fort Dent Park, the forcemain will cross to the rail lines along the south margin of the park, crossing multi- purpose grass fields with occasional deciduous and evergreen trees. From the southeast end of Fort Dent Park, both forcemain alternatives involve jacking the pipeline under the rail lines and following the existing ETS forcemain alignment to Metro's treatment plant at Renton. This alignment follows an unpaved road used for access from Monster Road S.W. to the rail lines. Vegetation is very limited in this section. b. What kind and amount of vegetation will be removed or altered? Tukwila Trunk. Construction of the Tukwila Trunk will involve disruption of landscaped areas both north and south of I -5. These areas consist of grass and small ornamental trees. The large drainage ditch adjacent to Interurban Avenue S. will be avoided. Just south of the Val Vue • Connection, vegetation in the deep drainage ditch (described above) which runs perpendicular to the pipeline will be removed as the trunk is installed below the bottom of the ditch. This section of pipeline will be tight- sheeted, so the amount of vegetation lost will be limited to a corridor of about 15 feet. Interurban Pumping Station. Construction at the new pumping station site will involve removal of minor amounts of vegetation on the 0.3 acre site. This site has been highly altered and little vegetation of significance is present. Interurban Forcemain. Forcemain Alternative A will involve removal of golf course vegetation (e.g. grass, Douglas fir, ornamentals) principally between the golf course footbridge and the railroad embankment. The proposed alignment will cross fairways 11 through 15, and may result the removal of several Douglas fir trees (about 30 feet in height). Greens will be avoided. 24 • • On the east side of the rail lines, the route will follow the existing ETS pipeline alignment. North of the Black River, much of this corridor has been highly altered by industrial activities and little vegetation is present along much of the route. In Fort Dent Park, construction of Forcemain Alternative A will involve additional removal of grass through a 30 to 40 foot construction corridor. As far as possible, existing trees and shrubs will be avoided. However, Alternative A may affect several Douglas fir trees (20 to 30 feet in height) in the northeast corner of the park where the forcemain crosses under the railroad tracks. Depending on the alignment and distance from the fenced property line, up to 13 maple trees and one pine tree may be adversely affected along the northeast perimeter of the park. This alignment will run between the railroad embankment and Fort Dent Pond. It is probable that the forcemain can be installed without removing any of the birch trees (22 trees between 15 to 30 feet in height) located on the east side of the pond. However, an undetermined number of trees may be lost through root damage. Southeast of the pond and east of the soccer field and ball field (undeveloped), several Douglas fir trees (20 to 30. feet in height) may be affected, again depending on the final alignment. Forcemain Alternative B will involve removal of riparian vegetation on the river banks at the proposed pipebridge crossing to Fort Dent Park. Staging areas for construction of the bridge would involve removal of lawn in Fort Dent Park in the southwest portion of the park. It is likely that the loss of vegetation associated with installation of the forcemain from the river to the rail line will be limited to loss of turf and occasional small trees. From the southwest corner of Fort Dent Park to Metro's treatment plant at Renton, minor amounts of grasses and perennials along the railroad access road will be lost during construction. This area has been highly altered and losses are not expected to be significant. Similarly, a small amount of turf, shrubs and small trees may be lost during construction of the 25 forcemain and transition structure on the treatment plant site. c.. List threatened or endangered species or critical habitat known to be on or near the site. A search of the Natural Heritage Data System of the Washington State Department of Natural Resources was conducted in 1989 for another project which included the Interurban study area (Municipality of Metropolitan Seattle, 1990). The search for significant natural features found "...no records for rare plants, high quality native plant communities of native wetlands..." d. Describe proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on site. A number of measures can be employed to minimize construction - related impacts on vegetation: - Where existing vegetation has been disturbed as part of construction, these areas will be replanted as soon as practical after construction has been completed. Depending on location, these plantings will be native or ornamental grasses, groundcovers, shrubs and trees; - Forcemain alignments through the golf course and Fort Dent Park will avoid removal of trees wherever possible; - As far as possible, trees lost to construction will be replaced with trees of similar size and species; additional trees may also be planted to offset the size difference between lost trees (20 -30 feet) and nursery stock (14 to 16 feet); some trees may be moved using a large tree "spade ", if transplanting takes place during dormancy; - Contractors will be required to take special precautions to avoid impacts on wetland areas, streams and drainages adjacent to construction corridors (e.g. drainage along Interurban Avenue S., Duwamish River shorelines, Fort Dent Park Pond); - Installation of the forcemain on the golf course will occur within the February 1 - • 26 • March 15 period in order to enhance resodding success and related site restoration efforts; and - In the event that streamside rehabilitation is necessary, particular attention will be given to a "beneficial" waterside planting scheme designed to enhance the fishery related habitat. 5. Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: Invertebrates: shellfish, insects, other Fish: bass, salmon, trout, herring, other Amphibians: frogs, salamanders, other Reptiles: lizards, snakes, turtles, other Birds: hawks, heron, eagle, sonctbirds, ducks, other Mammals: deer, bear, elk, beaver, rabbit, other Of the entire pipeline corridor, wildlife was observed in greatest concentration in Fort Dent Park Pond. Wildlife using the pond area on the day of the field visit included Canada geese, mallards, domestic ducks and geese, red - winged blackbirds, song sparrows, gold finches, and frogs. Salmon may utilize the extreme lower portions of the large drainage near the Val Vue Connection at certain times of the year. b. List any threatened or endangered species or critical habitat near the site. The Washington State Department of Wildlife reviewed their files for information on the occurrence of special animals within or adjacent to the Duwamish River corridor in 1989 as part of another project (Municipality of Metropolitan Seattle, 1990). Two species were identified: the great blue heron (Ardea herodias) and the bald eagle (ialiaeetus leucocephalus). 27 . • The great blue heron has been designated a "monitor" species by the Washington State Department of Wildlife. The nearest major rookery is located east of the Metro treatment plant at Renton. Bald eagles are considered "threatened" under both federal and state criteria. Bald eagles are observed with some frequency in the Duwamish Valley, recently in the vicinity of the heron rookery cited above. c. Is the site part of a migratory route? If so, explain. The Tukwila Trunk corridor, the new pumping station site, and alternative forcemain routes are not known to be specific parts of migration routes. However, in a larger sense, the Duwamish Valley supports a wide variety of migratory waterfowl, raptors and songbirds. d. Proposed measures to preserve or enhance wildlife, if any. Faciltiy sites and alignments have been carefully selected to minimize .impacts on vegetation and wildlife. In addition, a number of spcecific mitigation measures can be implemented to reduce impacts on wildlife. - Replanting of disturbed areas along pipeline corridors as soon as practical will tend to reduce impacts on wildlife; - Where possible, replanting will use native plant species, thereby enhancing wildlife utilization; and - Scheduling of construction work at river crossings will be coordinated with fisheries agencies and tribes in order to reduce potential impacts on fishery resources. 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. During construction, fossil fuels will be utilized to power construction vehicles, equipment and haul trucks. Electrical energy may also be used to 28 • • operate some construction equipment (e.g. dewateririg pumps). Once operational, the Interurban Pumping Station will reduce electrical energy requirements used to operate pumps, controls, ventilation, odor control and lighting by approximately 570,000 kwh /year, compared to the existing pumping station. b. Would the project affect . the potential use of solar energy by adjacent properties? If so, explain. The project will not affect the potential use of solar power by adjacent property owners. c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any. Energy conservation measures will be incorporated into the design of the pumping station and forcemain. These will include: the use of energy efficient pumps and motors; selection of energy - efficient lighting and electrical systems; and insulation of the structure and heating systems. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spills, or hazardous waste that could occur as a result of this proposal? If so, describe. The only hazardous materials used for construction of the project will be fossil fuels (i.e. diesel, gasoline) used to power vehicles and equipment and various lubricants and solvents. It is possible that inadvertent spills of these substances could result in health hazards, however, the potential for adversely affecting the environmental health of workers and nearby residents is low. The new pumping station will, require chemical storage and feeding facilities in order to control hydrogen sulfide in the forcemain . Various chemicals are typically used for this purpose including caustic soda, sodium hypochlorite and 29 • • iron salts. A 5,000 gallon below grade storage tank will be provided for storage of the specific chemical selected for this purpose. • 1. Describe special emergency services that might be required. No special emergency services will be required. Standard first aid supplies will be kept on hand at construction sites by contractors. 2. Describe proposed measures to reduce or control environmental health hazards. Occupational Safety and Health Act (OSHA) regulations regarding safety equipment and procedures will be strictly enforced on construction sites. The storage and feeding facilities at the new pumping station will be designed to meet required safety provisions including secondary containment, alarms, annunciator, and vents, as well as spill response procedures. Increasing the capacity of the Tukwila Trunk will reduce the frequency and volume of sanitary overflows to the Duwamish River. This will have, a positive effect on public health and beneficial uses of the river. b. Noise 1. What types of noise exist in the area which may affect your project (for example: traffic, equipment operation, other)? There are a variety of noise sources in the vicinity of the proposed project, however, the existence of background noise will not affect the project. Tukwila Trunk Automobile and truck traffic on Interurban Avenue S., I -5 and SR -599 are the predominant sources of noise in the vicinity of the proposed Tukwila Trunk. Other noise sources in proximity to the site include: rail traffic on the Burlington Northern / Union Pacific rail lines east of the site; and air traffic 30 • • from Boeing Field and Sea -Tac International Airport. In general, background noise levels are typical of commercial / industrial areas. Interurban Pumping Station Noise sources in the vicinity of the proposed pumping station site are similar to those sources discussed for the Tukwila Trunk. Background noise levels are relatively high because of the volume of truck traffic on Interurban Avenue S. and the industrial character of the area. Renton Concrete Recyclers, located north of the Black River, is a significant source of noise, both from facility operation and haul truck activity. Forcemain The dominant noise sources in the vicinity of the proposed forcemain are automobile and truck traffic on Interurban Avenue South, I -5, I -405, rail traffic on the Burlington Northern / Union Pacific rail lines east of the site and the concrete recycling facility. More distant noise sources include automobile and truck traffic on SR -599 and air traffic using Boeing Field and Sea -Tac International Airport. Noise levels generally reflect the industrial nature of the area. 2. What types and levels of noise would be created by or associated with the project on a short - term or long -term basis (for example: traffic, construction, operation, other)? Construction of the various project elements will take place between the hours of 7:00 a.m. and 7:00 p.m. on weekdays. No weekend or evening work is anticipated. Tukwila Trunk Noise impacts will be generated by construction activities and equipment and by haul trucks and worker vehicles. Excavation will be accomplished using conventional equipment such as backhoes and graders. These typically result in noise levels of approximately 80 to 85 dBA at a distance approximately 50 feet from the source. Overall, based on the types of equipment and • 31 • • activities anticipated, average noise levels ranging from 76 to 91 dBA (at 50 foot distance) can be expected. Installation of sheetpiles will be accomplished using vibratory pile drivers. Use of vibratory pile drivers can reduce noise levels approximately 30 percent at the source, or about 30 dBA, compared to impact pile drivers. Maximum noise levels expected are about 70 to 71 dBA, 50 feet from the source. Construction vehicles will generate noise on area roadways. Heavy trucks (three or more axles) generate about 83 dBA at 40 miles per hour and 87 dBA at 60 mph, according to Federal Highway Administration estimates. It is expected that most truck traffic approaching the site will be travelling 40 mph or less. Consequently, peak noise levels generated by heavy trucks will be up to approximately 83 dBA. Project area roadways, including Interurban Avenue S., currently experience significant volumes of truck traffic and associated noise levels. The additional construction- related traffic associated with the Tukwila Trunk is not expected to cause noticeable noise increases. Over the long term, operation of the Tukwila Trunk will not generate any significant noise. Interurban Pumping Station Pumping station construction will last approximately 18 months. The first phase, lasting approximately four months, will include excavation, foundation and structural work. The second phase, lasting approximately 14 months, will include mechanical and electrical work. Noise impacts will be generated by construction activities and equipment and by haul trucks and worker vehicles. Excavation for the pumping station will be accomplished using conventional equipment such as backhoes and graders, which typically result in noise levels of approximately 80 to 85 dBA at a distance of 50 feet from the source. Overall, based on the types of equipment and activities anticipated, average noise levels ranging from 32 • • 76 to 91 dBA (at 50 foot distance) can be expected. This noise level is roughly consistent with the existing noise levels in the area, which is heavily influenced by truck traffic along Interurban Avenue S. If ground water is encountered during construction, installation of sheetpiles for dewatering will be accomplished using vibratory pile drivers. Use of vibratory pile drivers results in noise levels of approximately 70 dBA at a distance of about 50 feet from the source. Approximately 60 one -way truck trips per day will be generated during initial site excavation, lasting approximately one week. Most trucks will access the site via Interurban Avenue S. Following initial site excavation, material delivery truck trips will average four to six one -way trips per day with a peak of 20 one -way trips per day. Each truck trip will generate peak noise levels up to 83 dBA, however, this impact is not expected to be noticeable to surrounding receptors because of the existing high level of truck use on Interurban Avenue S. Golfers may notice the additional noise, especially when playing near the construction site. The completed pumping station will not result in significant noise impacts. The pumping station structure will be insulated to reduce pump, generator and fan noise to the extent that pump station operation will be essentially indistinguishable from other local noise sources. Forcemain Forcemain construction will generate noise levels roughly similar to Tukwila Trunk construction, described previously. The duration of noise disruption along any given section of forcemain will, however, be reduced because less excavation will be required (forcemain trench depth will be 5 to 6 feet compared to 25 feet for the Tukwila Trunk). For Alternative A, the nearest receptors include the golf course, light industry located along Interurban Avenue S., light 33 • industrial uses adjacent to the Burlington Northern / Union Pacific rights -of -way and Fort Dent Park. Construction within the golf course will occasionally place construction activity within 100 feet of golf activity. Peak noise levels at this site could reach 91 dBA on occasion. Forcemain Alternative A will cross the Duwamish -Green River on the existing foot bridge located in Foster Golf Links. It is expected that the forcemain can be hung from the existing bridge. Consequently, noise levels typically associated with new bridge construction activities (e.g. floating equipment, cranes, concrete trucks) are not likely to occur. Pipe installation will be accomplished relatively quickly using land - based equipment. The forcemain will then cross the golf course where it will be bored or tunneled beneath the Burlington Northern / Union Pacific rights -of- way. Under this alternative the nearest sensitive noise receptor will be users of the golf course. Peak noise levels at this site could reach 91 dBA on occasion. Some disruption of golf activities may occur as players wait for peak noise levels to subside. Construction of Forcemain Alternative B will result in noise levels similar in nature and duration to those described above. This alignment will require a greater amount of pavement breakup than Alternative A. Pavement breakup will generate noise levels up to 90 dBA at 50 foot distance for short periods. Forcemain Alternative B involves a new crossing of the Duwamish (Green) River near the south end of Fort Dent Park. This will be either a new pipe bridge or a tunnel under the river. Peak noise levels could reach 100 dBA if impact piledrivers are used for construction of a new bridge. Additional noise from floating construction equipment (e.g. diesel engines, generators, cranes) will also be generated.. These types of equipment can be expected to generate intermittent noise levels ranging from 70 to 95 dBA at a distance of 50 feet. 34 If the forcemain is jacked under the river, noise levels can be expected to be similar to those which will occur when the forcemain is jacked under the rail lines. For short periods of time, jacking equipment will generate high noise levels (e.g. greater than 90 dBA at 50 foot distance) for intermittent periods. This noise will be noticeable to Fort Dent Park users, particularly in the south end of the park. The completed forcemain will not generate any significant long -term noise impacts. 3. Describe proposed measures to reduce or control noise impacts, if any. The following measures can be implemented to mitigate noise impacts: - Limiting construction of the various project elements to the hours of 7:00 a.m. to 7:00 p.m. on weekdays; - Use of properly sized and maintained mufflers and use of engine intake silencers and engine enclosures where possible; - Turning off equipment when not in use; - Locating stationary construction equipment away from sensitive receiving properties where possible; - Shielding particularly noisy equipment by temporary attenuation barriers; and - Substituting hydraulic or electric models for impact tools such as jack hammers, rock drills and pavement breakers. 8. Land and Shoreline Use a. What is the current use of the sites adjacent to the property? Tukwila Trunk The proposed Tukwila Trunk parallels Interurban Avenue S., passing through commercial /light 35 industrial, residential and recreational areas. North of I -5, the alignment is characterized by commercial /light industrial uses. There are two large office parks (Tukwila Business Park, Gateway Corporate Center) and several gas stations /truck stops. South of I -5, the new Tukwila Trunk alignment will continue south within the City Light right -of -way between Foster Golf Links, a 71 -acre golf course and Interurban Avenue S. The trunk will terminate at the new pumping station at the south end of the golf course. In addition to the golf course, nearby land uses include an apartment complex and commercial /light industrial uses. Interurban Pumping Station The pumping station site is Interurban Avenue S. at the Golf Links (south side of S. proposed pumping station undeveloped. Adjacent land Gglf Links and the City of sHops to the east. located adjacent to south end of Foster 139th Street). The site is currently uses include Foster Tukwila maintenance Forcemain There are two alternative routes for the 20 -inch forcemain from the new Interurban Pumping Station to the Metro treatment plant at Renton. Forcemain Alternative A passes through areas characterized by recreational (Foster Golf Links / Fort Dent Park), transportation (Burlington Northern / Union Pacific rail lines), industrial (quarry) and utility (Metro treatment plant at Renton) uses. Similarly, Forcemain Alternative B passes through areas characterized by recreational (Fort Dent Park), transportation (Burlington Northern / Union Pacific rail lines), commercial / industrial (various) and utility (Metro treatment plant at Renton) land uses. b. Has the site been used for agriculture? If so, describe. Historically, the project site may have been used for agriculture. However, the pumping station site 36 and Tukwila Trunk and forcemain alignments will be constructed in areas which are already developed. c. Describe any structures on the site. The Tukwila Trunk and forcemain alignments will be constructed almost entirely in private and public rights -of -way. Structures along the alignments are limited to utility facilities, paved roadways, curbs and sidewalks. The pumping station site is currently undeveloped. d. Will any structures be demolished? If so, what? The existing Interurban Pumping Station, located on the west side of Interurban Avenue S. across from Foster Golf Links, will be removed. e. What is the current zoning classification of the site? Tukwila Trunk The entire corridor for the Tukwila Trunk is located within the City of Tukwila. North of I -5, zoning is "M -1 Light Industry ". The M -1 district is intended: ... to provide area for light industrial uses which are non - nuisance activities in terms of air and water pollution, noise, vibration, glare and odor." (City of Tukwila, 1982). The Foster Golf Links adjacent to Interurban Avenue S., south of I -5 is zoned "R -A Agricultural." This zoning designation is intended: "...to preserve and protect existing agricultural lands and uses; and to preserve agricultural land which may be suited to eventual development to other more intensive urban uses." (City of Tukwila, 1982.) The golf course is a conditional use under this designation. • • The Tukwila Trunk corridor south of I -5 lies within the "Interurban Special Review District ". This district has been established because of "...its unique physiography, the presence of natural amenities and recreational facilities, the historical relevance of the area to the community and the contemplated future mix of residential, commercial, industrial, and public land uses... "(City of Tukwila, 1982). Any development in the district, with the exception of single family dwellings, must be reviewed and approved by the Board of Architectural Review. Interurban Pumping Station Zoning is "M -1 Light Industrial" at the pumping station site. The purposes of this zoning designation is as described above for the Tukwila Trunk. The pumping station site also lies within the "Interurban Special Review District" (See above.). Forcemain The alternative forcemain alignments lie within the Cities of Tukwila and Renton. City of Tukwila zoning along Interurban Avenue S. is "M -1 Light Industry "; zoning in Fort Dent Park is "R -A Agricultural." Descriptions of uses permitted under these designations have been described previously for the Tukwila Trunk. Much of the forcemain lies within the City of Tukwila's "Interurban Special Review District." Any development in the district, with the exception of single family dwellings, must be reviewed and approved by the Board of Architectural Review. The section of the forcemain that follows the Burlington Northern / Union Pacific rail lines (east side) to the Black River is located in the City of Renton. The current zoning designations • • for this area are "L -1 Light Industrial" and "M -P Manufacturing Park." The purpose of L -1 zoning is "... to provide areas for low intensity, non - nuisance generating in terms of odor, air and water pollution, noise, vibration and glare, industrial activities." (City of Renton, undated). The purpose of M -P zoning is "...to provide for a wide variety of industrial, transportation, service and office activities whcih meet high operational, development and environmental standards." (City of Renton, undated). f. What is the current comprehensive plan designation of the site? Tukwila Trunk The current comprehensive plan designation for the Tukwila Trunk alignment north of I -5 is light industrial and commercial. South of I -5, the comprehensive plan designation is parks and open space, commercial and high density residential. Interurban Pumping Station The comprehensive plan designations for the new Interurban Pumping Station site is light industrial. Forcemain The City of Tukwila comprehensive plan designation for the Forcemain Alternative A, on the west side of the Duwamish (Green) River is light industrial. On the east side of the river, Alternative A is located in area designated parks and open space. Sections of both forcemain alternatives (A and B) are located in the City of Renton. The alignments pass through areas designated manufacturing park /multiple option, heavy industrial and public /quasi - public. g. • • If applicable, what is the current shoreline master program designation of the site? Tukwila Trunk Sections of the Tukwila Trunk which lie within 200 feet of the Duwamish River are subject to the provisions of the City of Tukwila Shoreline Master Plan (City of Tukwila, 1974). The extreme northern section of the Tukwila Trunk near the Val Vue Connection and a several hundred foot section just south of I -5, lie within 200 feet of the Duwamish River. The City of Tukwila shoreline master program designation for the Green /Duwamish River is "Urban Environment" (City of Tukwila, 1974). Interurban Pumping Station The Interurban Pumping Station site is more than 200 feet from the River and is consequently not subject to the provisions of the city's shoreline plan. Forcemain Sections of the alternative forcemain alignments lie within 200 feet of the Duwamish River and are designated "Urban Environment" by the Tukwila shoreline plan. These include the existing Foster Golf Course bridge and the proposed Fort Dent Park' bridge and their respective approaches. The Black River in the City of Renton is designated "natural" under the City of Renton Shoreline Master Program (City of Renton, 1985). A section of the Green River shoreline immediately southeast of Fort Dent Park is designated "urban." h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. The Tukwila Trunk corridor lies within the "Interurban Special Review District." Any development in the district, with the exception of single family dwellings, must be reviewed and approved by the Board of Architectural Review. In addition, the Green River has been designated a "shoreline of statewide significance." 40 i. Approximately how many people would reside or work in the completed project? Interurban Sewer System improvements will not require the presence of permanent staff. Metro staff will visit the pumping station several times each week for operation and maintenance purposes. Pump repair and /or station refurbishment will require maintenance staff to work on the pumping station for several weeks every three to five years. . Approximately how many people would the completed project displace? The proposed project will not displace any people. k. Describe proposed measures to avoid or reduce displacement impacts, if any. Not applicable. 1. Describe proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any. The Tukwila zoning code does not explicitly prohibit or permit pipeline or pumping station within any particular zoning area. The proposed Tukwila Trunk could be considered an "unclassified use" defined as: ... unusual, large - scale, unique or special form as to make impractical their being included automatically in any class of use as set forth in the various use districts previously defined." Construction of the Tukwila Trunk, new Interurban Pumping Station and Interurban forcemain will require Interurban Avenue Special Review District review and approval. Review ensures the proposal is compatible with and sensitive to existing amenities and land uses. The trunk and forcemain will not change land use within or adjacent to the proposed pipeline corridor. 41 • • Following construction, the Tukwila Trunk and forcemain corridors will be landscaped to achieve compatibility with the adjacent land uses. Construction adjacent to the golf course will require Interurban Special Review District review and approval. Following construction, the site will be landscaped to' achieve compatibility with the adjacent golf course and the Green River Trail along Interurban Avenue S. 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low - income housing. The implementation of this project will neither add new housing nor eliminate existing housing. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low - income housing. Not applicable. c. Describe proposed measures to reduce or control housing impacts, if any. Not applicable. 10. Aesthetics a. What is the tallest height of any of the proposed structure(s), not including antennas? What is the principal exterior building material(s) proposed? The new Interurban Pumping Station will average 14 feet in height; maximum height above grade will be 16 feet. The odor scrubber vent will be 8 to 10 feet above grade. The principle exterior building material will be concrete or CMU construction. The pumping station will incorporate a public art element, probably on the west side of the structure where it will be visible from Interurban Avenue S. and the pedestrian / bicycle path. 42 b. What views in the immediate vicinity would be altered or obstructed? No long term adverse impact on views will result from implementation of the proposal. The pumping station will alter views from the Foster Golf Links to the industrial / commercial areas to the south, however, the new station can be expected to improve the appearance of this currently undeveloped area. Views from Interurban Avenue S. will be altered, as the pumping station structure replaces undeveloped commercial / industrial areas, however, the new pumping station will be designed to be compatible with existing and proposed uses of the immediate area. The Tukwila Trunk and Interurban forcemain will be underground except for the river crossings at Foster Golf Links and the Black River (Forcemain Alternative A) or Fort Dent Park (Forcemain Alternative B). At these locations, the 20 -inch forcemain will be visible from the bridge approaches and the river itself. The pipeline will be designed to be as unobtrusive as possible. The design of the golf course footbridge crossing and the Fort Dent Park pipebridge crossing must be reviewed and approved by the City of Tukwila under provisions of the Interurban Special Review District. c. Describe proposed measures to reduce aesthetic impacts, if any. Tukwila Trunk The proposed Tukwila Trunk will not change land use within or adjacent to the proposed pipeline corridor. The right -of -way is already in use by a similar facility, the Renton Effluent Transfer System (ETS). Following construction, the Tukwila Trunk corridor will be landscaped to achieve compatibility with adjacent land uses, including business parks, Foster Golf Links and the Green River Trail along Interurban Avenue S. Interurban Pumping Station Construction at the pumping station site adjacent to the golf course will require Interurban Special 43 Review District review and approval. Review ensures the proposal is compatible with and sensitive to existing amenities and land uses. Following construction, the pumping station site will be landscaped to achieve compatibility with the adjacent golf course and the Green River Trail along Interurban Avenue S. Public art will be incorporated into the design of the pumping station. This will be oriented toward bicyclists and pedestrians using the trail along Interurban Avenue S. Forcemain The proposed forcemain will not significantly change land use within or adjacent to the proposed pipeline corridor. The most significant change will be the river crossing at the existing Foster Golf Course footbridge or the new pipebridge / footbridge at Fort Dent Park. Design of either of these crossings will require review and design approval by the City of Tukwila. Following construction, the forcemain corridor will be restored (i.e. replanted, repaved) to achieve compatibility with adjacent land uses including the golf course, the Green River Trail and /or Fort Dent Park. 11. Light and Glare a. What type of light and glare will the proposal produce? What time of day would it mainly occur? Construction is expected to occur during daylight hours, typically between 7:00 a.m. and 7:00 p.m. During late fall and early winter when days are short, some temporary lighting may be used briefly in the early morning or late afternoon. No large scale lighting is anticipated. Over the long -term, the completed project will not produce any light or glare. Exterior lighting of the pumping station will be subdued and limited to that required for security purposes. 44 • • b. Could light or glare from the finished project be a safety hazard or interfere with views? The completed pumping station is not expected to produce light or glare which could be a safety hazard, nor will it interfere with views. c. What existing off -site sources of light or glare may affect your proposal? There are no off -site sources of light or glare which might affect the project. d. Describe the proposed measures to reduce or control light and glare impacts, if any. The completed pumping station will utilize subdued exterior lighting as needed for security purposes. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? Foster Golf Links, the Green River Trail, and Fort Dent Park are the major designated recreational opportunities in the area. The Duwamish /Green River is the major informal recreational resource in the area. Foster Golf Links is a 71 -acre golf course located between Interurban Avenue S. and the Duwamish (Green) River. The golf course lies on both sides of the Duwamish /Green river; the east and west sides are connected by a footbridge. A completed section of the Green River Trail runs along Foster Golf Links to S. 139th Street. The trail is designed for bikes and pedestrians. Another trail segment, from S. 141st Street to Fort Dent Park's entrance, is now being designed. Fort Dent Park is a large athletic park owned and operated by King County Natural Resources and Parks Division. The park is bounded on the north, west and south by the Duwamish -Green River and by Burlington Northern / Union Pacific rail lines on the east. The park has softball and soccer fields, large grassy areas, children's play areas, picnic tables and restroom facilities. There is a large pond at the park's eastern edge near the rail line embankment. 45 The proposed Black River Trail, part of the City of Renton's Regional Trails Master Plan, is intended to link Fort Dent Park, the Black River Forest and the Empire Ridge Trail. b. Would the proposed project displace any existing recreational uses? If so, describe. Tukwila Trunk and Interurban Pumping Station South of I -5, the trunk will be constructed between Interurban Avenue S. and the golf course. Construction activities at the southeast end of the golf course will include the pumping station and sections of the Tukwila Trunk and forcemain. Construction- related traffic, noise, odor and dust may temporarily affect Foster Golf Links users to some degree. At the same time, existing noise levels on the course are relatively high because of the proximity of the course to the railroad, Interurban Avenue S., the Boeing Field flightpath and I -5. Construction along the sidewalk may displace Green River Trail users. Pedestrian and bicycle traffic will be detoured around construction. Forcemain Alternative A involves construction of an 20 -inch pipeline east from the new pumping station, parallel with the existing ETS line, through Foster Golf Links, over the golf course footbridge to the Burlington Northern / Union Pacific rail lines. This alternative will disrupt the southern end of Foster Golf Links, specifically the two holes (Nos. 11 and 16) located on either side of the footbridge and the four holes (Nos. 12 through 15) located south of the footbridge. Construction- related noise, dust, odors and traffic will disrupt golf course users. The extent and magnitude of this disruption will depend on the actual pipeline alignment, the duration of construction and the time of year construction occurs. Construction of the section of forcemain which will be routed through the golf course is expected to occur during the period February 1 through March 15. This is a period when golf course usage is comparatively low. Use of the existing footbridge by golfers will be maintained throughout the construction period. 46 • In Fort Dent Park, construction - related noise, dust, odors and traffic will disrupt weekday park activities on the athletic fields and other park areas. Specific park areas affected may include the softball fields at the north end of the park; the large pond and trail in the east central part of the park; and the eastern end of the soccer stadium. The level of disruption will depend on the duration of construction and the time of year construction occurs. It is expected that construction within the park will take from two to three months. It is likely that construction will occur during the period April through October. Forcemain Alternative B involves routing the forcemain from the new Interurban Pumping Station site south parallel to Interurban Avenue S. to near S. 149th Street, then east to the Duwamish River. A section of the Green River Trail from S. 141st Street to Fort Dent Park's entrance is now being designed. Depending on when construction of this trail section occurs, users may be disrupted during construction of the forcemain. Once in Fort Dent Park, the forcemain will continue east across a large playing field to the main access road. From there it runs south to a location near the park entrance, where it turns east to the Burlington Northern / Union Pacific right -of -way in the southeast corner of the park. Route selection through the park has been designed to minimize disruption of park activities, however, some disruption is likely to -occur, especially in the west central portion of the park and along the access road and parking areas. Vehicle and pedestrian circulation within the park will be maintained at all times. Construction will typically occur during daytime hours on weekdays. No construction is likely to occur during peak use periods (i.e. weekends). No long term disruption of recreational opportunities will result from implementation of the project. • • c. Describe proposed measures to reduce or control impacts on recreation, including recreational opportunities to be provided by the project or applicant. Proposed measures to reduce or control the project's short -term construction - related impacts on recreation may include the following: - minimizing the size of disturbed areas along the pipeline corridors and at the new pumping station site; - minimizing excavation and other earthwork within shoreline zones; - restoring disturbed areas (i.e. replanting, repaving) as soon as practical after construction has been completed; - scheduling construction in recreation areas (i.e. Foster Golf Links, Fort Dent Park) for non -peak use periods; - maintaining access to recreational areas at all times; and - rerouting pedestrian and bicycle traffic around construction sites using temporary fences and signs. 13. Historic and Cultural Preservation a. Are there any places or objects listed on or eligible for national, state, or local preservation registers known to be on or next to the site? If so, generally describe. Investigations associated with Metro's Renton ETS and Metro treatment plant at Renton - Phase III Expansion (Municipality of Metropolitan Seattle, 1984, 1991) projects identified several prehistoric sites in the Duwamish Valley. One of these, Site 45KI267, is on a small hill northwest of the Metro treatment plant at Renton. Cobble tools and siltstone flakes and chunks were recovered which appeared to be derived from an Olcott occupation that dates 4,000 to 8,000 years ago. The site is not eligible for the National Register of Historic Places because of disturbance to the site. The 48 • site is located in the proposal's general vicinity but not in or immediately adjacent to any of the proposed forcemain alignments. A large portion of the proposed Tukwila Trunk and Interurban forcemain corridors was surveyed for cultural resources prior to construction of the Renton ETS pipeline. Based on the results of that investigation, it is unlikely that cultural artifacts are present where the trunk sewer and forcemain lie adjacent to the Renton ETS pipeline. b. Generally describe any landmarks or evidence of historic, archeological, scientific, or cultural importance known to be on or next to the site. The Duwamish Tribe occupied the Duwamish and Black River Valleys and the lower portions of the Cedar and White (Green) River Valleys. Extended villages or bands occupied specific locations along the rivers, selected for their importance for fishing and hunting. The confluence of the Black / Duwamish / White (Green) Rivers was one such location, called "Mox La Push," a Chinook word meaning "two mouths." The Duwamish villages Sgwa'lgo, S'quli'ls, and Tau we'dits were located near the confluence of the rivers. There are also a number of locations with religious significance for the Duwamish Tribe. The knoll • north of the Metro treatment plant at Renton, referred to as "swa'wa tix t d," is significant in terms of Duwamish mythology. It is possible that the hill was used for ceremonies and burials (Municipality of Metropolitan Seattle, 1991). The City of Tukwila Comprehensive Plan (1982) provides a map of historic sites. The map depicts areas and sites which are relevant to the city's history. The following sites are located adjacent to the proposed project: Tukwila Trunk Site Explanation Puget Sound Also called the "Interurban", E l e c t r i c the PSER was the region's first Railroad mass transit system. The system operated from 1902 to 1928. 49 • • I n t e r u r b a n The first road linking Tacoma Avenue S. and Seattle. Footbridge at 56th Avenue S. Bridge at 56th Bridge Bulkhead reads, "Time Avenue S.* Capsule 1985 ", possibly indicating the placement of artifacts in the bulkhead. Historic boat landing at 56th Avenue S . bridge. A small c o n c r e t e memorial marker marks the site.* Forcemain Historic boat landing, just north of S. 144th Street Fort Dent Historic boat l a n d i n g , adjacent to Fort Dent Park Ball Fields. A small c o n c r e t e memorial marker marks the site.* Black River "Foster Landing at Foster Homestead" commemorating the flat bottom boats that sailed between the Duwamish -Green and Black Rivers between 1854 and 1886. A Tukwila boat landing site once used by small steamers traveling the Duwamish -Green River. Site of a blockhouse built during the Indian wars, 1855- 1858. Commemorates the flat bottom boats that went between the Duwamish -Green and Black Rivers between 1854 and 1886. The Black River drained Lake Washington before the lake was lowered in 1916. * Identified during field observations and not identified on Tukwila's historic sites map. 50 • • c. Describe proposed measures to reduce or control impacts, if any. If historical or archeological artifacts are uncovered at any of the proposed construction sites, construction will cease and the State Office of Archeology and Historic Preservation immediately contacted to determine the importance of the artifacts. Additionally, the Muckleshoot tribe will be contacted to assist in the determination of the importance of any such artifacts. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. Major highways in the project vicinity include I -5, SR 599, and I -405. Arterials serving the general project vicinity include Interurban Avenue S., East Marginal Way S., S.W. Grady Way and Empire Way S. Access to Interurban Avenue S. and East Marginal Way S. is provided by I -5 and SR -599. Access to S.W. Grady Way is provided by I -405 or Interurban Avenue S. Construction vehicles will access the Tukwila Trunk alignment via Interurban Avenue S. The proposed Interurban Pumping Station will be accessed via Interurban - Avenue S. and S. 139th Street. Access to forcemain segments on the west side of the Duwamish River is provided via Interurban Avenue S., S. 139th Street, and the entrance road to Fort Dent Park. On the east side of the rail lines, access to forcemain segments is provided via Monster Road S.W., Beacon Coal Mine Road, 68th Avenue S. and Oaksdale Avenue S.W. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Metro's Tukwila Park - and -Ride facility is located at Interurban Avenue S. and 52nd Avenue S. Seven transit routes serve the Park - and -Ride daily. Interurban Avenue S. is a "main transit street." Transit stops are located on both sides of Interurban Avenue S. from the Park - and -Ride lot to I -405. 51 • • There is no transit service on Monster Road S.W. or Oaksdale Avenue S.W. on the east side of the Duwamish River. c. How many parking spaces would the completed project have? How many would the project eliminate? Implementation of the proposal will not eliminate parking spaces. The Interurban Pumping Station will be designed with 3 to 4 parking spaces for maintenance vehicles. During construction, worker vehicles and construction equipment will be parked on construction sites or in designated parking areas. Existing parking areas in commercial or industrial areas will not be used by construction workers or visitors. In Fort Dent Park, construction workers will use designated parking areas only; these may include small portions of existing parking areas within the park. Existing parking areas at the treatment plant will not be used by construction workers, nor is any loss of existing parking anticipated during construction of the forcemain. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe. The proposal may involve improvements to the proposed pumping station site's access road (S. 139th Street). This is an unimproved two -lane road east of Interurban Avenue S. and is currently used for access for golf course maintenance. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. Neither the proposed Tukwila Trunk nor the Interurban Pumping Station will be constructed in the immediate vicinity of water, rail, or air transportation. Forcemain alternatives, however, involve a number of river and rail crossings. Forcemain Alternative A involves river crossings of the Duwamish (Green) River near S. 139th Street and a Black River crossing just east of the BNRR right - of -way. Forcemain Alternative B involves a crossing of the Duwamish (Green) River near the south end of Fort Dent Park. Each of these proposed crossings will be bridge structures. 52 Neither the Duwamish (Green) nor the Black Rivers support water transportation in this area although recreational boating may occur periodically in the Duwamish (Green) River. Any construction involving floating construction equipment will be scheduled so as not to interfere with any treaty protected fishery which may occur in the Duwamish (Green) River or the Black River. If Forcemain Alternative A is selected, the forcemain will be jacked under the Burlington Northern / Union Pacific rail lines at three locations: a) near the southeast end of Foster Golf Links, b) just south of the Black River, and c) at the southeast corner of Fort Dent Park. If Forcemain Alternative B is chosen, the forcemain will be jacked under the rail lines at the southeast corner of Fort Dent Park. Jacking techniques have been chosen in order to avoid any disruption of rail traffic along these rail lines. Construction activities are not expected to affect any rail operations in this area. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Tukwila Trunk Once operation of the new Tukwila Trunk is initiated, there will be only occasional vehicle trips for inspection and maintenance purposes. Construction of the new Tukwila Trunk is expected to take about 6 months. It is estimated that about 50 feet of pipeline can be installed each working day. Heavy trucks will haul excavated material (17,000 cubic yards) from the pipeline alignment and haul bedding and fill material (17,000 cubic yards), pipe and ancillary equipment to the construction sites. This will amount to an average of about 60 one -way haul truck trips per day over the course of the construction period. Construction workers are expected to number from 6 to 12 at any given time. Construction workers are expected to drive private vehicles to the project site, generating an additional 12 to 24 one -way trips each day. Parking areas for construction workers will be established within the construction corridor in order to avoid use of existing parking areas used by local businesses. 53 • • Construction of the Tukwila Trunk will slightly increase traffic volumes on Interurban Avenue S., I -5, and to a lesser degree SR 599. Construction is expected to occur during typical daytime working hours. Nighttime or weekend work is not anticipated. Interurban Pumping Station The completed pumping station will generate an average of 5 one -way trips per week for inspection and maintenance purposes. Every 3 to 5 years when major pump repairs and /or station refurbishment occurs, there will be about 4 one -way trips per day for several weeks. It is also possible that additional trips would be necessary in the event of an emergency. All but emergency trips are likely to occur during daytime working hours. Parking for 3 to 4 vehicles will be provided at the pumping station site. Construction of the pumping station is expected to take about 18 months. Construction will generate a maximum of 60 one -way truck trips per day during the initial excavation phase (approximately 2 weeks). Following the excavation phase, construction will generate approximately 4 -6 one - way truck trips per day with an occasional maximum of 20 one -way truck trips per day. The number of construction workers will range from an estimated 18 during excavation and structural work to about 6 during final construction and startup. Workers will generate up to 36 one -way trips per day during the first 3 -4 months of construction. After the first 4 months of construction, workers will generate an estimated 12 -20 one -way trips per day. A designated parking area will be established for construction worker vehicles in order to minimize disruption at the south end of the golf course. This parking area will be established in a location which will not hinder access to the south end of the golf course. Construction of the new pumping station will slightly increase traffic volumes on Interurban Avenue S., I -5, and to a lesser degree I -405 and Grady Way S.W. Construction is expected to occur during typical daytime working hours. Nighttime or weekend work is not anticpated. 54 • • Forcemain After the forcemain becomes operational, there will be occasional vehicle trips to various locations along the alignment for purposes of inspection and maintenance. Construction of the forcemain is expected to take about 4 months. As with the Tukwila Trunk, heavy trucks will haul excavated material (3,500 cubic yards) from the pipeline alignment and haul bedding and fill material (3,500 cubic yards), pipe and ancillary equipment to the construction sites. This will generate a daily average of about 12 one - way trips over the course of construction. As with the Tukwila Trunk, construction workers are expected to number from 6 to 12 at any given time. Construction workers are expected to drive private vehicles to the project site, generating an additional 12 to 24 one -way trips each day. Along the construction corridor, designated parking areas for construction worker vehicles will be established in order to minimize congestion and parking problems for local business establishments and recreational facilities (i.e. Foster Golf Links, Fort Dent Park). During construction through the golf course, workers will be required to park vehicles in designated parking areas near the new pumping station. During construction in Fort Dent Park, a portion of the existing parking facilities will be designated for construction worker use. Construction of the new forcemain will slightly increase traffic volumes on Interurban Avenue S., the Fort Dent Park access road, I -5, Monster Road S.W. and, if Forcemain Alternative A is selected, Beacon Coal Mine Road, 68th Avenue S., Oakesdale Avenue S.W. and S.W. Grady Way. Construction is expected to occur during typical daytime working hours. Nighttime or weekend work is not anticpated. The new forcemain will cross Monster Road S.W. and enter the Metro treatment plant at Renton near the main entrance gate. There is some potential for traffic disruption in this area during construction because of the vehicles entering and leaving the plant during daytime hours. The forcemain will be installed in the area using open cut methods. It 55 is expected that the forcemain can be installed across Monster Road S.W. and the treatment plant entrance road in a period of several days. Traffic controls will be implemented to ensure that access to the plant is maintained at all times and that any disruption of traffic is kept to a minimum. There is some potential for cumulative traffic impacts at Metro's treatment plant at Renton if construction schedules for the Interurban project and proposed treatment plant improvements coincide. (Refer to Draft Supplemental Environmental Impact Statement: Metro Treatment Plant at Renton, Phase III Enlargement (Metro, 1991) for a detailed discussion of traffic impacts associated with the plant expansion.) g. Describe proposed measures to reduce or control transportation impacts, if any. Mitigation measures intended to reduce transportation impacts include the following: - minimizing delivery or removal of materials during peak traffic hours; - using flaggers to direct traffic at construction sites as necessary; - locating worker parking within the construction zone or in specially- designated areas; - maintaining access to businesses and recreational facilities at all times; - minimizing the width of the construction zone; - minimizing open trench lengths and the amount of time trenches are left open; - jacking the pipeline under I -5 and under rail lines in order to avoid disruption of surface and rail traffic; - locating jacking pits outside access ramps to and from I -5 in order to minmize congestion at these locations; and 56 • • - establishing a designated haul route within Fort Dent Park to minimize potential conflicts with park users. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally explain. Implementation of this project will not increase the need for public services. The project will improve sanitary sewer service in the City of Tukwila and will result in the more efficient conveyance of flows from the Val Vue Sewer District to the Metro system. The frequency of overflows to the Duwamish River is expected to decrease as the capacity of the Tukwila Trunk is increased. b. Describe proposed measures to reduce or control direct impacts on public services. Measures to reduce or control impacts on public services will not be necessary. 16. Utilities a. Circle utilities currently available at the site: Electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic systems, other All of the above underlined utilities are available in the vicinity of the pumping station and forcemain alternatives. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. The new Interurban Pumping Station will utilize electrical energy to convey wastewater through the forcemain to the Metro treatment plant at Renton. An uninterruptible power supply will be provided to maintain power to pumping station instrumentation and controls. Puget Sound Power and Light Company will provide electrical service. The pumping station will also be equipped with exterior electrical service plug receptacle to 57 • • allow connection to a portable electrical generator. A second backup power source may be provided. Water, sewer, and telephone services will also be provided at the new pumping station. Electrical power will also be required to power the odor control unit located at the new pipebridge crossings at the Black River (Forcemain Alternative A) and at the south end of Fort Dent Park ( Forcemain Alternative B). C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: e -• Date Submitted: dile /r/ 58 • • • REFERENCES Golder Associates, Inc. "Preliminary Geotechnical Study: Tukwila Trunk Sewer Rehabilitation Project, Tukwila, Washington." Prepared for Municipality of Metropolitan Seattle. July 1990. Municipality of Metropolitan Seattle, Environmental Analysis - Task 390, Alki Transfer - CSO Control Facilities Project, Seattle, Washington. 1990. Municipality of Metropolitan Seattle, Final Plan for Secondary Treatment Facilities -Volume II, Plan for Secondary Treatment Facil-ities and Combined Sewer Overflow Control, Seattle, Washington, 1985. Municipality of Metropolitan Seattle, Facilities Plan for Alki Transfer - CSO Control Facilities Project, Seattle, Washington, 1990. Municipality of Metropolitan Seattle, Predesign Report for Alki Transfer - CSO Control Facilities Project, Seattle, Washington, 1990. Municipality of Metropolitan Seattle, Draft Supplemental Environmental Impact Statement: Metro Treatment Plant at Renton - Phase III Enlargement, Seattle, Washington, 1991. City of Renton. City of Renton: Comprehensive Plan (Compendium). Policy Development Department, Renton, Washington. March 1986. City of Renton. "Land Clearing and Tree Cutting Ordinance." Ordinance No. 4219, Renton, Washington. June 1989. City of Renton . Shoreline Master Program: City of Renton. Ordinance No. 3758 as amended. Renton, Washington. December 1983. City. of Renton Planning Department and Northwest Environmental Consultants, Inc. City of Renton Wetlands Study: A Reconnaissance Study of Selected Wetlands in the City of Renton. Renton, Washington. February 1981. 24 p. Shapiro and Associates, Inc. "Wetland Delineation of the Container Corporation of America Site, Renton, Washington," Prepared for Bruce Blume and Company, Seattle, Washington. June 1989. 26 p. City of Tukwila. City of Tukwila: Water Resource Rating and Buffer Recommendations. Prepared by Jones and Stokes, Associates, Inc., Tukwila, Washington. May 1990. 59 City of Tukwila. City of.Tukwila: Shoreline Master Plan. Prepared for City of Tukwila Planning Department by Jones & Jones, Consultants. Ordinance #898 as amended. Tukwila, Washington. June 1974. City of Tukwila. The Tukwila Zoning Code. City of Tukwila Planning Department, Tukwila, Washington. Undated. City of Tukwila. City of Tukwila: Comprehensive Land Use Policy_ Plan. Planning Division, Department of Community Development. Ordinance #1246. Tukwila, Washington. March 1982. 60