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HomeMy WebLinkAboutD_ERC_SEPA_Addendum_Apron R_190118.pdfDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT SR_ERC_SEPA_Addendum_Apron R_180110 ADDENDUM TO ENVIRONMENTAL (SEPA) DETERMINATION OF NON-SIGNIFICANCE (DNS-M) Pursuant to WAC 197-11-600(4)(c) and WAC 197-11-625 Addendum to Boeing Apron R Infrastructure Maintenance and Repair (LUA17-000631, ECF) as Addended by the City of Renton Determination of Non-Significance - Mitigated (DNS-M) Date of Addendum: January 14, 2019 Date of Original Issuance of SEPA Threshold Determination: December 18, 2017 Proponent: Mark Clement, The Boeing Company Project Number: LUA17-000631, ECF, SM, SMC-H Project Name: Boeing Apron R Infrastructure Maintenance and Repair Proposal / Purpose of Addendum: The subject property totals 6,677,748 square feet (153.3 acres) and is located in the Commercial Mixed Use Comprehensive Plan (COMP-CMU) land use designation and Urban Center (UC) zoning classification. The site is currently developed with a variety of industrial and office buildings related to the manufacturing of 737 airplanes at the Boeing plant. The northern portion of the site where the work on Apron R will occur is located within a Regulated Shoreline overlay area. The maintenance and repair work on Apron R will include concrete replacement and outfall repair within 200 feet of the Lake Washington shoreline, as well as in-water fill, bulkhead replacement, and riparian habitat installation below the ordinary high water mark (OHWM). The original threshold determination for the Boeing Apron R Infrastructure Maintenance and Repair project was issued on December 18, 2017 (Exhibit 2). After the issuance of the original threshold determination, it came to City staffs attention that the applicant failed to disclose the need for the use of trucks to haul a substantial amount of fill material. The fill material would be used for both preloading the area of work and filling in a portion of Lake Washington for the apron expansion per the approved Shoreline Conditional Use Permit (LUA17-000631). The intended purpose of this SEPA Addendum is to disclose any proposed changes to the project. The revised project requires a revision to the approved Shoreline Substantial Development Permit (LUA17-000631) due to construction that would occur within Reach A of the Cedar River in the Shoreline High Intensity Designation. In order to allow for construction dump trucks to more easily access the Boeing plant site near Apron R, the applicant has proposed a temporary access road embankment at the north end of the construction site across an existing drainage ditch between Nishiwaki Lane and the project site. Construction of the temporary ditch crossing DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD SR_ERC_SEPA_Addendum_Apron R_180110 would require the installation of a 12” culvert encased in quarry spall material topped with a gravel base and approximately 3” of asphalt (see Exhibit 5). A guard shack and rolling security gate would also be installed on the Boeing plant side of the ditch in order to control access to the site. The temporary guard shack would include one full-cut off light directed toward the ground and away from the Cedar River. After project completion, the applicant would remove the temporary road crossing over the ditch and restore the ditch to its existing, natural state. In addition, the applicant would be responsible for repaving and restriping approximately 0.5 miles of Nishiwaki Ln per a future license agreement between the City and the applicant. Truck hauling for the fill is expected to occur during eight separate construction phases between January of 2019 and January of 2021. Concentrated high-volume traffic would occur at the start and end of each phase and may consist of up to 120 trucks per day. Each truck trip would consist of a fully loaded dump truck with a tandem wheel pup trailer. The proposed truck route (see Exhibit 3) shows trucks exiting I-405 onto N Southport Dr (turns into Logan Ave N west of Park Ave N). Trucks would then travel south on Logan Ave N until reaching N 6th St and would then turn right and continue straight approximately 1,000 feet until entering into the Cedar River Trail Park on Nishiwaki Lane. Once on Nishiwaki Ln, trucks would continue traveling north until reaching the temporary ditch crossing where they would turn right into the Boeing plant site and dump their loads. Empty trucks leaving the site would follow the same route in reverse in order to access I-405. The license agreement in-progress between the City and Boeing will include a number of requirements related to safety that will be implemented such as the presence of flaggers and spotters, time-of-day haul restrictions, speed restrictions, and various other precautions. Pursuant to the City of Renton's Environmental Ordinance and SEPA (RCW 43.21C, 1971 as amended), on June 10, 2013, the Environmental Review Committee issued a Determination of Non-Significance (DNS) for Northwest Gourmet. The 14-day appeal period ended on December 28, 2013. No appeals of the threshold determination were filed. Analysis: It has been determined that the environmental impacts of the proposal were adequately addressed under the analysis of significant impacts contained within the previously adopted DNS-M. Based on WAC 197-11-600(4)(c), the addendum process may be used if analysis or information is added that does not substantially change the analysis of significant impacts and alternatives in the existing environmental document. The proposed transportation of fill through the Cedar River Trail Park and removal of vegetation within 200 feet of the Cedar River OHWM is temporary in nature would is directly related to the approved work for the Apron R insfrastructure project, which was analyzed as part of the original SEPA theshold determination. The proposed hauling would not change the original analysis or significantly impact the 1995 State Environmental Policy Act (SEPA) Review. The City of Renton is hereby issuing a SEPA Addendum pursuant to WAC 197-11-600. This Addendum is appropriate because it contains only minor information not included in the original Determination and there are no additional environmental impacts related to inclusion of the new information. Location: 737 Logan Ave N, Renton, WA 98055 (APN 1823059254) DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD SR_ERC_SEPA_Addendum_Apron R_180110 Lead Agency: City of Renton, Department of Community & Economic Development Review Process: Addendum to previously issued Determination of Non-Significance - Mitigated (DNS-M) Additional Information: If you would like additional information, please contact Alex Morganroth, Associate Planner, City of Renton Planning Division, Department of Community & Economic Development at (425) 430-7219. There is no comment period for this Addendum, dated January 10, 2019 issued by the City of Renton Environmental Review Committee. Exhibits Exhibits 1-25: Contained within the original ERC and HEX Documents Exhibit 26: DNS Addendum Exhibit 27: Environmental Review Committee Report (LUA17-000631, ECF), dated December 18, 2017 Exhibit 28: Haul Route Map Exhibit 29: Site Plan Exhibit 30: Culvert Cross-Section ENVIRONMENTAL REVIEW COMMITTEE SIGNATURES: Gregg Zimmerman, Administrator Public Works Department Date Kelly Beymer, Administrator Community Services Department Date Rick M. Marshall, Administrator Renton Regional Fire Authority Date C.E. “Chip” Vincent, Administrator Department of Community & Economic Development Date DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD 1/15/2019 | 10:42 AM PST 1/15/2019 | 8:33 AM PST 1/15/2019 | 10:13 AM PST DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT ERC REPORT 17-000631 ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC MEETING DATE: December 18, 2017 Project Name: Boeing Apron R Infrastructure Maintenance and Repair Project Number: LUA17-000631, SSDP, CUP-H, ECF Project Manager: Alex Morganroth, Associate Planner Owner: The Boeing Company, 737 Logan Ave N, Renton, WA 98055 Applicant/Contact: Mark Clement, PO Box 3707, MC 96-01, Seattle, WA 98124 Project Location: 737 Logan Ave N, Renton, WA 98054 Project Summary: The applicant is requesting a Shoreline Substantial Development Permit, a Hearing Examiner Shoreline Conditional Use Permit, and an Environmental Threshold Determination (SEPA) for the proposed maintenance and repair of Apron R. Apron R is located on northern portion of the Boeing Plant site (Parcel #0723059001) at 737 Logan Ave N. The northern portion of the site where the proposed work would occur is located within a Regulated Shoreline overlay area. Further identified as Reach I of Lake Washington, the upland area has a Shoreline designation of Shoreline High Intensity and the waterward area to the north has a designation of Aquatic. The 153.30 acre site is zoned UC - Urban Center and is located in the Commercial Mixed Use land use designation. The primary function of Apron R is the transportation of completed airplanes from the Boeing Plant site to the Renton Municipal Airport. The towing of the airplanes between the assembly line and the air field is a critical function of Apron R, with an average of 42 airplanes per month utilizing the Apron R transportation corridor. The aprons secondary function is to provide space for the staging of completed airplanes when undergoing final checks and inspections. The proposed work on Apron R would occur within 200 feet of the Lake Washington Shoreline, with additional work occurring below the ordinary high water mark (OHWM). The proposed work within 200 feet of the shoreline includes the replacement of all concrete on the apron and various stormwater improvements. The work proposed to occur below the OHWM includes the conversion of the existing overwater pile-supported section of the apron to fill, a 3,165 sq. ft. water-ward expansion of the apron using in-water fill, construction of a 192 foot long structural wall to contain the new fill, bulkhead replacement along a large section of the apron, aquatic habitat enhancement, and riparian plant installation along the new bulkhead. A Shoreline CUP is required for any excavation or fill below the OHWM. The total new impervious surface proposed is approximately 3,200 sq. ft. Due to the scope of the in-water work, the applicant has also submitted a Joint Aquatic Resources Permit Application to the USACE (Permit #NWS-2017-37), which is currently in review. The applicant has submitted an Arborist Report, a Technical Information Report, a Geotechnical Engineering Study, a Standard Lake and Habitat Report, and a Draft Biological Assessment with the application. Critical areas mapped on the site include a high seismic hazard, and a habitat conservation area. The applicant has proposed the removal of five trees and various vegetation on the DNR mitigation site to the north of the apron as part of a utility removal project. The applicant has also proposed the removal of non-native and invasive species located near the shoreline along the DNR property. Entire Document Available in Laserfiche Submittals Folder EXHIBIT 27 DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 2 of 15 ERC REPORT 17-000631 Site Area: 6,676,701 SF (153.3 acres) STAFF RECOMMENDATION: Staff Recommends that the Environmental Review Committee issue a Determination of Non-Significance - Mitigated (DNS-M). Project Location Map: PART ONE: PROJECT DESCRIPTION / BACKGROUND The applicant is requesting Environmental (SEPA) Review for the repair and maintenance of Apron R – a critical piece of infrastructure on the Boeing plant site. Apron R is located on the south shore of Lake Washington on the Boeing Plant site. The primary function of Apron R is to provide a corridor for the transportation of Boeing 737 aircraft from the Boeing Plant site to the Cedar River Bridge which connects the plant to the Renton Municipal Airport. The apron, approximately 14 acres in size, was originally constructed in the early 1940s and is partially supported by wood piles driven into the Lake Washington lake bed. Apron R also serves as an area for the staging of aircraft to undergo systems checks, minor modifications, or the temporarily storage of airplanes prior to transportation to the airport. Improvements proposed across the entire apron includes concrete replacement and utility trenching in order to replace existing electrical, compressed air, fire, storm water, and communications utilities. The applicant provided a DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 3 of 15 ERC REPORT 17-000631 breakdown of the proposed repair activities based on three distinct parts of the apron: Area 1 – West Apron Improvements, Area 2 – East Apron Improvements, Area 3 – Central Apron Improvements (see map below). Area 1 – West Apron Improvements Improvements on the west portion of the apron would result in approximately 6.3 acres of pavement replacement, the replacement of pile-supported structures with slab on grade, the replacement of the existing bulkhead, installation of new storm-water treatment facilities, the installation of aquatic habitat and shoreline function enhancement in Lake Washington, and the replacement of security fencing between the plant site and the airport. The applicant has proposed the construction of a new 192-foot long structural wall in Lake Washington that would reclaim approximately 10,765 sq. ft. of lake. The combined pile-supported apron and west ramp is a structure approximately 11,200 sq. ft. in size. Overwater coverage of the combined structure is approximately 7,600 sq. ft., and during a 2015 inspection, was determined to be supported primarily by untreated timber piling and concrete pile caps. The applicant has proposed constructing a new structural wall and increasing the size of the current section of apron by approximately 3,165 sq. ft. As part of the West Apron Improvements, the applicant has also proposed to fill the existing overwater structure and new section of apron, resulting in a total of 10,765 of new lake fill. The area proposed for fill contains a “pinch-point” between Building 4-41 and the lake that provides only 130 feet of clearance for the planes when transported between the plant and the airport. According to the applicant, the extension of the apron further into the lake represents the smallest possible area that will allow for an airplane bypass route during reconstruction of the existing west apron. The bypass route is important in order to allow for continuous aircraft production during the construction project. Within Area 1, the applicant has also proposed the demolition of the center ramp and west ramp (approximately 7,800 sq. ft. in area), resulting in the removal of approximately 4,200 sq. ft. of overwater coverage. The area of the center ramp would be converted to nearshore shallow water habitat and the west ramp would be replaced by a structural wall and the associated fill. According to the studies provided by the applicant, the existing bulkhead wall along the DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 4 of 15 ERC REPORT 17-000631 shoreline of Area 1 has deteriorated and necessitates the replacement of approximately 500 linear feet of wall in order to support the proposed new pavement on the apron. On the waterward side of the proposed new bulkhead, the applicant has proposed the creation of a new riparian planting zone and habitat enhancement area that will slope downwards into the water and significantly improve the ecological function of the shoreline in the project area. In addition, a location for barges to load/unload materials will be formalized to the east of the existing center ramp by reducing the amount of aquatic habitat enhancement material in the area of the barge slip and installing steel piles to prevent barges from making contact with the bulkhead wall. Area 2 – East Apron Improvements Improvements on the east apron include the installation of a new stem wall to raise the apron elevation and relocation of a storm water outfall in the lake. The existing bulkhead wall wraps across approximately 300 feet of the apron shoreline. The existing inner sheet pile bulkhead that supports Apron R has deteriorated significantly and is in need of replacement. The new stem wall along the east property line, approximately 263 feet long, would be located approximately 10 feet landward of the existing inner-pile wall located near the west property line and would not require any over- or in-water work. The replacement of pavement and utilities are also proposed for the east apron area. Area 3 – Central Apron Improvements The central apron area is located adjacent to the DNR mitigation property. Improvements on the central apron would be limited to the utility and pavement replacing proposed for the entire apron. Existing utilities would be completely removed from the DNR mitigation property and relocated into a conduit on the Boeing plant property. The applicant has proposed the removal of five trees on the DNR property as well as moderate disturbance to vegetation within the utility easements. Disturbed or removed trees and vegetation would be replaced in order to provide no net loss of ecological function for the property. Two new storm water outfalls would be installed within easements on the DNR properties and drain into the lake further water-ward than the existing outfalls. Utility replacement and pavement replacement, identical to the work to within the east and west apron areas, is proposed for the central apron area. PART TWO: ENVIRONMENTAL REVIEW In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project impacts that are not adequately addressed under existing development standards and environmental regulations. A. Environmental Threshold Recommendation Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials: Issue a DNS-M with a 14-day Appeal Period. B. Mitigation Measures 1. If any Native American grave(s) or archaeological/cultural resources (Indian artifacts) are found all construction activity shall stop in accordance with RCW 27.53.060 and 27.44.020, and the owner/developer shall immediately notify the City of Renton planning department, concerned Tribes’ cultural committees, and the Washington State Department of Archeology and Historic Preservation. 2. The applicant shall submit an Archaeological Monitoring and Inadvertent Discovery Plan MIDP to DAHP and any interested Tribes for review prior to the start of any ground disturbing activities. Documentation of the submittal shall be provided to the City of Renton prior to the issuance of building or construction permits, whichever comes first. 3. The applicant shall comply with the recommendations of the geotechnical report prepared by PanGEO, dated September 2017, or an updated report submitted at a later date. DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 5 of 15 ERC REPORT 17-000631 4. The applicant shall comply with the recommendations of the Standard Lake Study and Habitat Report prepared by BergerABAM and Amec Foster Wheeler, dated July 17, 2017, or an updated report submitted at a later date. 5. All construction or restoration work to occur on the DNR property (parcel #0723059105) shall be in accordance with a mitigation plan approved by the DNR. The approved mitigation plan shall be provided to and approved by the Current Planning Project Manager prior to construction permit application submittal. 6. The applicant shall comply with the recommendations included in the Draft Biological Assessment prepared by BergerABAM and Amec Foster Wheeler, dated June 2017, or an updated report submitted at a later date. 7. The applicant shall work with the City to relocate the existing easement (Recording #9609040765) to the location of the original easement (Recording #9209171541) or another location approved by Community Services Department. The relocated easement shall be recorded prior to Construction Permit issuance. Alternatively, the applicant could proposed to incorporate the trail design into the mitigation plan and build the trail in the location of the existing easement as a part of the Apron R construction permits. 8. The applicant shall grant the City a minimum 10-foot wide public trail easement running parallel to the entirety of the proposed stem wall on the east side of property. The easement shall be reviewed and approved by the Community Services Department and the City Attorney’s Office. Once approved the easement shall be recorded prior to construction permit issuance. C. Exhibits Exhibit 1 Environmental Review Committee Report Exhibit 2 Project Narrative Exhibit 3 Neighborhood Detail Map Exhibit 4 Construction Drawings (select pages) Exhibit 5 Environmental Checklist Exhibit 6 Shoreline Tracking Worksheet Exhibit 7 Construction Mitigation Description Exhibit 8 Geotechnical Report prepared by PanGEO Inc (dated September 2017) Exhibit 9 Standard Lake Study Narrative and Habitat Report prepared by BergerABAM and Amec Foster Wheeler (dated July 2017) Exhibit 10 Draft Biological Assessment prepared by BergerABAM and Amec Foster Wheeler (dated June 2017) Exhibit 11 Technical Information Report prepared by BergerABAM (dated September 2017) Exhibit 12 Arborist Report prepared by Davey Group (dated November 2017) Exhibit 13 Department of Archeological and Historic Preservation Comment Letter (dated October 24, 2017) Exhibit 14 King County Wastewater Treatment Division Comment Letter (dated October 24, 2017) Exhibit 15 Department of Natural Resources (DNR) Comment Letter (dated October 24, 2017) Exhibit 16 Department of Transportation (WSDOT) Comment Letter (dated October 26, 2017) Exhibit 17 Boeing Response Letter to DNR (dated November 20, 2017) Exhibit 18 Boeing Response Letter to WSDOT (dated November 20, 2017) Exhibit 19 Department of Natural Resources (DNR) 2nd Comment Letter (dated December 13, 2017) Exhibit 20 Documents Relating to Sam Chastain Trail Exhibit 21 Advisory notes to Applicant DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 6 of 15 ERC REPORT 17-000631 D. Environmental Impacts The proposal was circulated and reviewed by various city departments and divisions to determine whether the applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with the proposed development. Staff reviewers have identified that the proposal is likely to have the following probable impacts: 1. Earth Impacts: The subject site is located in an area of a known seismic hazard. As such the applicant submitted a Geotechnical Report, prepared by PanGEO Inc, dated September 2017 (Exhibit 8). The analysis in the report primarily focused on the area near the proposed Apron repair project. The recommendations contained within the geotechnical report relied on the soil characteristics observed during borings used for prior geotechnical reports prepared for Boeing, as well as new cone penetration tests conducted on the site in May of 2017. PanGEO performed eight cone penetration tests (CPT) using a truck-mounted rig. A CPT uses an instrumented one-inch diameter cone to test for properties such as tip resistance, friction ratio, and pore pressure. The testing occurred across the Apron R work area at maximum depths ranging from 43 to 57 feet below grade. According to the new testing results and data from previous borings, the existing Apron pavement is generally underlain by 4 to 10 feet of compacted structural fill over approximately 10 to 20 feet of very soft organic and inorganic silt. The organic silt is generally underlain by loose to medium dense silty sand that extends to 100-plus feet deep. Groundwater was indicated at about 3 feet below the ground surface in previous borings and it is anticipate that due to the proximity of the lake, the groundwater level at Apron R is very similar to the water level in Lake Washington. Levels are also likely to vary seasonally and are heavily influenced by the water level in the lake. According to the City of Renton Critical Areas Maps, the project site is located in a seismic hazard area. A seismic evaluation of the site found a moderate to high potential for liquefaction during a seismic event due to the presence of ground water and loose silty sand near the project site. Other potential liquefaction- related hazards are possible without a seismic event include ground settlement and lateral spreading. The applicant has not proposed any liquefaction mitigation methods. PanGEO evaluated two types of pavement sections that may be used for the project: New Portland Cement Concrete surfacing overlying crushed aggregate base course, and New Portland Cement Concrete surfacing overlying soil-cement treated subgrade. Both options are required to conform to the FAA Advisory Circular 150/5320-6E issued in 2009 – a standard created for all infrastructure associated with commercial aircraft. The report does not expect the potential load demand on the apron, including front loaders, aircraft, cranes, or forklifts, to exceed the design loads of either pavement option. If option 1 is selected, the report recommends that layer of construction geotextile be placed on the subgrade before placement and compaction of the crushed aggregate. If option 2 is chosen, the report recommends that soil-cement stabilization be applied to the subgrade soils once grading of the subgrade soils has occurred. The report specifically evaluates the feasibility of the proposed replacement of the pile-supported apron near the west ramp. Due to the significant presence of untreated timber piles currently supporting the existing apron structure, the report recommends driving the majority of the piles below the mudline and removing select piles that impede installation of the temporary sheet pile wall. After the piles are driven below the mudline or removed, the fill used to support the new slabs is expected to range from four to eight feet in depth. The report make recommendations on the appropriate types of backfill to use for both submerged and above level placement. Additional subgrade stabilization may need to occur if the subgrade appears soft or easy to disturb during construction. Due to the presence of compressible soils, PanGEO anticipates immediate ground settlement as well as a high probability of long-term secondary compression in the area where new in-water fill will be placed. The DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 7 of 15 ERC REPORT 17-000631 report recommends adding several feet of surcharge fill on the area near the west ramp in order to reduce the anticipated settlement period of the fill. Recommendations for the new 192-foot long bulkhead wall and rock containment dike to be constructed in order to contain the new fill include overbuilding the containment dike to accommodate the anticipated settlement, use of clean, well graded crushed rock, using no greater than a 2H:1V slope. The existing bulkhead system on the northeast corner of the site in Area 2 is proposed to be raised approximately 3-4 feet on the landward side of the proposed stem wall. The report recommends that the existing grades within at least 10 feet of the existing bulkhead wall should not be raised in order to avoid adding additional pressure against the wall, unless the existing wall can be modified or a new bulkhead wall is proposed to be built. The applicant has not proposed any modification to the existing bulkhead wall and should therefore follow the recommendation of the report to raise the ground surface landward of the existing bulkhead in Area 2 During the installation of the temporary or permanent sheetpiles, the report recommends the contractor drive one pile at time in order to avoid liquefaction caused by the vibratory hammer. In addition, the existing timber piles near the northeast corner of the project site should be closely monitored during sheetpile constructing to ensure the vibratory hammer does not cause any movement. Temporary excavation and shoring is likely to occur in wet conditions. Construction dewatering will likely be necessary utility systems replacement. Groundwater collected during the excavations will be discharged into temporary on-site infiltration trenches. The report recommends excavating the temporary trenches or pits no more than two feet below the existing grade in order to avoid hitting groundwater. Temporary trenches should be closely monitored and should be cleaned out regularly to avoid clogs. Infiltration trenches may also be expanded to avoid potential overflow caused by higher than anticipated discharge rates. The applicant ha s indicated the project would result in approximately 3,165 sq. ft. of new impervious area and apprximately 527,000 sq. ft. of replaced impervious surface. Erosion control measures will need to be in place prior to starting grading actitivies of the site. The report submitted at the time of contruction permit application should disucss soil and groundwater characteristic in more depth, analyze infiltration potential, and provide recommendations for project design and contruction. Mitigation Measures: The applicant shall comply with the recommendations of the geotechnical report prepared by PanGEO, dated September 2017, or an updated report submitted at a later date. Nexus: SEPA Environmental Review, RMC 4-4-060 Grading, Excavation and Mining Regulations 2. Air Impacts: It is anticipated that some temporary air quality impacts could be associated with site work and building construction required to complete the proposed project at this site. Project development impacts during construction activities may include dust as a result of concrete replacement, bulkhead installation, and utility work, as well as exhaust from construction vehicles, equipment and/or machinery. These emissions would be temporary and are anticipated to rapidly dissipate. Dust control would be mitigated through the use of temporary erosion control measures, watering or other best management practices as identified in the construction mitigation memo provided by the applicant (see Exhibit 7). No further site specific mitigation is recommended for the identified impacts from typical vehicle and construction exhaust. Mitigation Measures: No further mitigation recommended. Nexus: N/A 3. Water a. Wetlands, Streams, Lakes DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 8 of 15 ERC REPORT 17-000631 Impacts: The project site is located along Lake Washington, a Shoreline of the State. The southern portion of Lake Washington adjacent to the project site is designated High Intensity by the Shoreline Master Program. The outflow of Lake Washington is the Lake Washington Ship Canal. Lake Washington has been altered significantly over the past century and the development along the shoreline has contributed to loss of habitat primarily due to new overwater structures, removal of riparian vegetation and large woody debris, and an increase in shoreline armoring. Due to the majority of the proposed improvements being located within 200 feet of the Lake Washington OHWM and waterward of the OHWM, the applicant submitted a combination Standard Lake Study Narrative and a Habitat Data Report, prepared by AMEC Foster Wheeler and dated July 2017. According to the study, no wetlands or streams were noted within the immediate vicinity of the project area. Although not noted in the reports, the site is approximately x feet from the Cedar River a stream of sate wide significant. The Standard Lake Study Narrative is provided under a separate section of the report and includes information on the existing habitat conditions and functions of Lake Washington adjacent to the proposed project site. According to the report, approximately 1,500 of the 2,600 linear feet of the Lake Washington shoreline along the project area consists of pile-supported concrete deck, concrete bulkhead, sheet-pile bulkhead, and riprap armoring. The remaining 1,100 feet linear of shoreline is occupied by a DNR shoreline habitat restoration area. The restoration area was constructed between 2013 and 2015 as part of required mitigation for the SR 520 floating bridge project. The report provides summaries of the potential impacts on the water and habitat in addition to mitigation measures proposed to help offset the loss of aquatic resources due to the project. In order to offset the loss of aquatic resources and lessen the impact of the proposed project, the applicant has proposed multiple mitigation measures adjacent to Apron R that would be implemented after the construction work is completed. The proposed mitigation is primarily designed to improve the nearshore aquatic habitat for juvenile salmonids along the south Lake Washington. The mitigation would be comprised of three elements: the installation of multiple fills to prevent undermining and to enhance the benthic habitat, the installation of multi-level fill slopes, and the installation of riparian plantings to improve the ecological function of the shoreline (see Exhibit 2). The goal of the first two elements, using multi-level fill slopes to support the multi-sloped benthic environment, would reduce wind/wave erosion in the new shoreline area while providing an improved, fish- friendly habitat for juvenile salmonids. This would be accomplished by installing loose riprap on the lakebed that would slope towards the water and away from the bulkhead and provide support for the benthic environment. On top of the mechanically-compacted riprap, a 2-foot thick habitat mix would provide a significantly improved environment for fish and other aquatic wildlife. Lastly, the enhancement plan would create a new near shore environment averaging 10 feet in width as measured waterward from the edge or the apron. The proposed shoreline would extend approximately 1 foot above the OHWM in order to create an area suitable for the planting of new riparian plant species. The addition of the new riparian planting zone would improve shoreline function by providing shade during the day, blocking artificial light sources at night, and increasing organic matter put into the lake. The primary focus of the report is to evaluate the proposed habitat mitigation measures in order to preserve and enhance riparian and shallow-water habitats for juvenile salmonids in Lake Washington. Mitigation measures proposed include the removal of invasive plant species and replacement with native riparian vegetation, the removal of shoreline armoring and the center ramp structure, and the creation of nearshore shallow-water habitat and riparian buffer. The study concludes with the installation and completion of the identified mitigation the proposed lake fill and other site changes would be mitigated and result in no net loss of ecological functions and values. Based on the recommendations included in the study, staff recommends as a mitigation measures that the applicant comply with the recommendations included in the Lake Study. Mitigation Measures: DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 9 of 15 ERC REPORT 17-000631 1. The applicant shall comply with the recommendations of the Standard Lake Study and Habitat Report prepared by BergerABAM and Amec Foster Wheeler, dated July 17, 2017, or an updated report submitted at a later date. 2. All construction or restoration work to occur on the DNR property (parcel #0723059105) shall be in accordance with a mitigation plan approved by the DNR. The approved mitigation plan shall be provided to and approved by the Current Planning Project Manager prior to construction permit application submittal. Nexus: SEPA Environmental Review, RMC 4-3-090 Shoreline Master Program Regulations b. Storm Water Impacts: The applicant submitted a Technical Information Report (TIR) prepared by DOWL, dated May 2017, and revised the study May 2017 (see Exhibit 13). Based on the updated TIR, the project contains greater than 2,000 SF of replaced impervious surface and therefore Full Drainage Review is required and the development is subject to the 2017 City of Renton Surface Water Design Manual (RSWDW). Based on the City’s flow control map, this site falls within the Peak Rate Flow Control Standard matching Existing Site Conditions. A Full Drainage Review was included in the report. The project site is located within the Lake Washington and Cedar River Drainage basins. The flow-path from the project site discharge point is less than 0.5 miles from the 100-year floodplain of Lake Washington and therefore qualifies for the direct discharge exemption in accordance with Section 1.2.3.1 of the RSWDW and must adhere to all requirements thereof. The area of the site improvements discharge into two separate threshold discharge areas that converge more than ¼ mile downstream. The project is classified as a redevelopment project in accordance with RSWDM. As a redevelopment project, the improvements are exempt from Core Requirement #8, Water Quality. Therefore, the development is exempt from the requirement to provide water quality treatment prior to discharge for each separate threshold discharge area. However, the applicant has elected to provide enhance water quality treatment prior to discharge in order to provide a benefit to Lake Washington and its aquatic habitat. Water quality treatment will consist of conveyance to oil/water separator vaults, which will direct surface water to several Linear Modular Wetland systems prior to discharge to the outfalls in Lake Washington. On-site BMPs will be required to help mitigate the new runoff created by the proposed improvements. The final drainage report submitted at the time of construction permit application should address the implementation of on-site BMPs. This includes analyzing the feasibility of basic dispersion for the target impervious surface areas that may be able to disperse into added or existing landscaped areas. A Stormwater Pollution Prevention Plan (SWPPP) is required for this site and the final drainage plan and drainage report must be submitted with the utility construction permit application. A Construction Stormwater General Permit from the Department of Ecology is required if grading and clearing of the site exceeds one acre. It is anticipated that the City’s current adopted 2017 City of Renton Surface Water Design Manual would adequately mitigate any impacts that could result from the proposed development; therefore no further mitigation is recommended. Mitigation Measures: No further mitigation required. Nexus: No applicable 4. Trees and Vegetation Impacts: The project site is primarily comprised of impervious, non-vegetated surface. A habitat survey of the site was conducted in order to assess the conditions and vegetative cover along the entire length (~2,600 DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 10 of 15 ERC REPORT 17-000631 linear feet) of the proposed Apron R project site. Approximately 1,500 feet of the 2,600 linear feet of the area along the north boundary of the site is comprised of pile-supported concreted deck, concrete bulkheads, or riprap sections. The remaining 1,100 linear feet of shoreline is occupied by a DNR shoreline habitat restoration area established as part of the SR 520 Bridge Replacement project. Aside from the DNR shoreline property adjacent to the area of work, riparian vegetation along the shoreline adjacent to the site is generally sparse and consists primarily of invasive, non-native species such as Himalayan blackberry, Japanese knotweed, and English ivy. Removal of the invasive species is proposed as a part of the project and would be replanted with native species. The WSDNR property contains a fifteen (15) foot wide easement along the apron granted to Boeing for electrical, water, and mechanical utilities. The majority of the DNR property, including the area around Boeing’s existing utility easement, is planted with trees and other native species as part of a WSDOT mitigation project required for the SR 520 Bridge Replacement completed in 2016. Boeing has been working with WSDNR on a plan to remove the utilities and relinquish the easement since 2016. As part of the Apron R project, Boeing agreed to relocate the utility lines onto Boeing property and install the lines in a buried conduit under the apron pavement. In the originally submitted Environmental Checklist and various studies, the applicant did not address the potential impacts to the vegetation and trees on the DNR property (Parcel #0723059105) that could result from the utility removal. Both WSDOT and the DNR both submitted comment letters requesting additional information on the potential impacts of the proposed work (see Exhibit 15 and 16). Boeing resubmitted an amended Environmental Checklist, Standard Lake Study and Habitat Data Report, and Arborist Report (all included as exhibits of this report) that included additional information on the impacts to trees and vegetation on the DNR property. Boeing also included official response letters to each agency that addressed the issues raised by the agencies during their first-round reviews. The City provided the response letters and new studies to WSDOT and DNR. The DNR provided a letter dated December 13, 2017 stating that Boeing’s response to the initial comment letter sufficiently addressed the agency’s concerns regarding restoration of the DNR property (see Exhibit 19). In addition, staff was informed on December 7, 2017 that Boeing, the DNR, and WSDOT will meet within the next few weeks to discuss the technical aspects of restoring the mitigation area on the DNR site after utility removal. The applicant has worked with DNR and WSDOT over the past few months to determine the more effective and least disruptive method to remove the utilities without negatively impacting the mitigation area. However, the parties have not been able to come to an agreement on the exact scope of work. After a mitigation plan is approved by the DNR, the applicant or DNR should provide copy of the plan to the city to ensure compliance with the Shoreline Master Program regulations or other approved plans. According the updated Standard Lake Study and Habitat Data Report and Arborist Report, the excavation of the utilities and expansion of the paved apron areas into critical root zones will necessitate both the removal and pruning of various trees on the DNR site. According the updated Arborist Report prepared by the Davey Group, the site has a total of 57 trees, 29 of which are classified as significant trees per City of Renton classifications (see Exhibit 12). Five trees have been identified for removal including the species bigleaf maple, Cascara buckthorn, vine maple, Scouler’s willow, and black cottonwood (see Exhibit 9, Figure 1). None of the trees proposed for removal are classified as landmark trees (under 30” DBH) and only two are classified as significant trees (over 6” DBH). In addition to the trees proposed for removal, another 37 trees have been identified for crown-raise pruning. Crown pruning removes the lower limbs of the tree and would reduce the likelihood of conflict and mechanical damage to tree limbs. According to the Arborist Report, crown-raising does not permanently damage the tree and will significantly increase the chance of the tree’s survival during the construction process. After the utilities are removed, the excavated material would be replaced and restored to its previous condition. In order to compensate for the disturbance, plant species matching existing conditions would be replanted at a higher density and size than what is currently on the site. In addition, removed trees would be replaced at a 1:1 ratio. The replacement trees will be installed slightly further water-ward in order to ensure DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 11 of 15 ERC REPORT 17-000631 they are replanted outside of the wing-tip clearance zone. Tree protection fencing will be installed around the retained trees prior to the start of construction activities and would coincide with the critical root zones areas identified for each tree. Based on the recommendations included in the Stream Study, Habitat Report and Arborist Report, staff recommends as mitigation measures that the applicant comply with the recommendations included in these studies including but not limited to re-vegetation of the DNR property and tree replacement at 1:1 ratio. Above under “Water” staff has already added a mitigation measure to comply with the stream study. Mitigation Measures: 1. The applicant shall comply with the recommendations included in the Standard Lake Study and Habitat Report prepared BergerABAM and Amec Foster Wheeler, dated July 17, 2017. 2. The applicant shall comply with the recommendations of the Arborists Report prepared by the Davey Group, dated November 2017, or an updated report submitted at a later date. 3. All construction or restoration work to occur on the DNR property (Parcel #0723059105) shall be in accordance with a mitigation plan approved by the DNR. The mitigation plan shall be provided to the Current Planning Project Manager prior to construction permit application submittal in order to review for compliance with City of Renton’s Tree Retention and Land Clearing Regulations in section RMC 4-4- 130. Nexus: SEPA Environmental Review, RMC 4-3-090 Shoreline Master Program Regulations, RMC 4-4-130 Tree Retention and Land Clearing Regulation”. 5. Wildlife Impacts: The project is located in an area of threatened species under the Endangered Species Act, the Puget Sound Chinook salmon and Puget Sound steelhead trout. In addition to the two threatened species WDFW Wildlife’s Priority Habitat and Species database identified five salmonid species that use the lower Cedar River, Chinook salmon, Coho salmon, Sockeye salmon, Steelhead, rainbow trout, and Coastal cutthroat trout. The study also identified the potential presence of bull trout in the upper Cedar River watershed. However, due to extremely limited reports of bull trout in the past few decades, the occurrence of bull trout in Lake Washington adjacent to the project site is expected to be minimal. The provided Lake Study and Habitat Report includes a wildlife analysis for area near the Lake Washington and the Cedar River in the project site vicinity (see Exhibit 9). The entire project area is highly developed and disturbed due to the presence of the Boeing plant site. The report concludes that with the exception of the WSDNR site, the shoreline area near the project site provides very low habitat value and function due to the sparse riparian vegetation and extensive development along the shoreline of both Lake Washington and the Cedar River. Within the DNR site shoreline area, biologists observed several bird species including the American crow, gulls, and European starlines. No mammals were observed near the project site but are likely to be present. Given the level of development in the project area, it is likely that only small mammals such as squirrels, mice, rats, etc, use the riparian areas along the lower Cedar River and Lake Washington shoreline within 100 feet of the project area. In addition, no amphibians or reptiles were observed during the site visits, but many species are found in the Lake Washington basin and are likely present within the site vicinity. The report concludes that impacts to land-based animals is expected to be minimal and temporary in nature. As part of the Apron R rehabilitation project, significant in-water work will occur below the OHWM. In-water work will include bulkhead replacement, construction of new structural wall, conversion of a 7,600 sq. ft. overwater coverage to fill, demolition of the existing center ramp, and aquatic habitat enhancement. The only portion of the project that could potentially affect aquatic biota is light impingement from the additional lighting proposed for the Apron project. In order to mitigate light impingement from the new and DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 12 of 15 ERC REPORT 17-000631 existing light sources, riparian vegetation will be planted along the entire span of the bulkhead in order to shield the near-shore area during nighttime hours. In order to reduce the impact of the in-water work on the wildlife and habitat near the project site, the work would be completed over three construction seasons. In-water work windows are designated in order to protect species and their habitats and are assigned during times when there is less likelihood of disturbance. Due to the scope of the work to be completed below the OHWM, Boeing has requested extensions for the in-water work windows either on the back or front end of the standard work windows. The agencies with authority to grant the extension include the National Oceanic and Atmospheric Administration, National Marine Fisheries Service, and the U.S. Fish and Wildlife Service, and will make a determination as part of the JARPA permit decision. Additional impacts to wildlife are identified in Section 7(a) Noise below. The Draft Biological Study prepared by Amec Foster Wheeler concludes that short-term impacts to the three salmonid species in the Lake Washington basin may including increased turbidity causing a decrease in water quality, temporary obstructions from machinery, and a change in behavior responses from juvenile salmonids due the noise caused by pile driving and use of a vibratory hammer (see Exhibit 9). The report identifies twenty (20) best management practices recommended for implementation in order to mitigate for the impacts to fish and other wildlife during construction. The study finds that the proposed project has the potential to affect the species identified within the project area (see Exhibit 9). The study concludes that project does not have the potential to adversely affect the Puget Sound Chinook Salmon or Puget Sound Steelhead Trout in the long term and will instead benefit the two species due to the coinciding shoreline habitat restoration that is part of the project. In addition, the project concludes that the proposed project will provide minimal, if any, long-term beneficial or adverse effects to Coastal/Puget Sound bull trout. Mitigation Measures: 1. The applicant shall comply with the recommendations included in the Standard Lake Study and Habitat Report prepared BergerABAM and Amec Foster Wheeler, dated July 17, 2017. 2. The applicant shall comply with the recommendations included in the Draft Biological Assessment prepared by BergerABAM and Amec Foster Wheeler, dated June 2017. Nexus: SEPA Environmental Review, RMC 4-3-090 Shoreline Master Program Regulations 6. Energy and Natural Resources Impacts: The types of energy likely to be used to implement the proposed project include gas-powered and diesel-powered vehicles and machinery. The use of these vehicles would be temporary. The completed project is not expected to require any energy. Mitigation Measures: No further mitigation recommended. Nexus: N/A 7. Environmental Health a. Noise Impacts: Noise and vibration impacts would primarily result from removal of the existing piles and the driving of the steel sheet pile wall installed against the existing timber sheet pile wall. The equipment noise would be regulated through the City’s adopted noise level regulations per Chapter 8-7, RMC. The City’s noise regulations limit haul hours between 8:30 am to 3:30 pm, Monday through Friday unless otherwise approved by the Development Services Division. Work on Saturdays is restricted to the hours between 9:00 a.m. and 8:00 p.m. No work is permitted on Sundays. DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 13 of 15 ERC REPORT 17-000631 Generally, noise impacts would come from the operation of the heavy construction equipment that would generate expected noise levels of up to 94 decibels. Underwater noise from vibratory extraction and driving of piles would be greater than that of other construction equipment. Underwater noise generated from the vibratory pile driving would be expected to be less than 150 decibels. The applicant indicates that all the construction noise impacts are anticipated to occur during normal daytime working hours and may occur on nights and/or weekends in order to complete the project within the restricted fish window (no in-water construction from January 1st through July 15th and August 1st through November 15th). The short 45-day construction window dictates the impacts would be temporary. If noise levels exceed maximum permissible levels as outlined in RMC 8-7, a noise variance would be required. A request for a noise variance lasting longer than two (2) days would require a public hearing and would be publicly noticed. Noise impacts are anticipated to be short-term impacts that would be completed within the approved fish windows. Additional staff analysis on noise impacts can be found under section “Wildflie”. Mitigation Measures: No further mitigation recommended. Nexus: N/A 8. Historic and Cultural Preservation Impacts: The SEPA checklist submitted by the applicant indicated that they completed a search of the Washington State Information System of Architectural and Archaeological Records Data. The Checklist concludes that the system did not identify any properties within the project area as being on the historic property inventory or register. A letter received from the State Historic Preservation Officer on behalf of the Department of Archaeology and Historic Preservation (DAHP), dated October 24, 2017 (see Exhibit 13 ), contained analysis and a recommendation related to the proposed improvements. There are two precontact archaeological sites recorded within 3,000 feet of the project area, as well as precontact trail systems. The presence of these sites and trails indicates that there is a high probability that the project site contains various precontact archaeological resources. As such, staff recommends as a mitigation measure that if any Native American grave(s) or archaeological/cultural resources (Indian artifacts) are found all construction activity shall stop in accordance with RCW 27.53.060 and 27.44.020, and the owner/developer shall immediately notify the City of Renton planning department, concerned Tribes’ cultural committees, and the Washington State Department of Archeology and Historic Preservation. The SEPA check list indicates that if any archaeological resources are encountered a professional Archaeologist would be called to assess the significance of the find. Due to parts of the proposed project that would occur under the existing impervious surface, DAHP has recommended that the applicant hire a professional archeologist to monitor ground disturbing activities. In addition, DAHP recommended the applicant prepare an archaeological monitoring and inadvertent discovery plan (MIDP) to be submitted to DAHP and the interested Tribes for review prior to any ground disturbance. Mitigation Measures: 1) If any Native American grave(s) or archaeological/cultural resources (Indian artifacts) are found all construction activity shall stop in accordance with RCW 27.53.060 and 27.44.020, and the owner/developer shall immediately notify the City of Renton planning department, concerned Tribes’ cultural committees, and the Washington State Department of Archeology and Historic Preservation. 2) The applicant shall submit an Archaeological Monitoring and Inadvertent Discovery Plan MIDP to DAHP and any interested Tribes for review prior to the start of any ground disturbing activities. Documentation of the submittal shall be provided to the City of Renton prior to the issuance of building or construction permits. Nexus: SEPA Environmental Review, RCW 27.53 Archaeological Sites and Resources, and RCW 27.44 Indian Graves and Records DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 14 of 15 ERC REPORT 17-000631 9. Recreation and Public Access Impacts: The Sam Chastain Trail is a regional, multiuse trail that circumnavigates Lake Washington. The trail is completely built out except for a small segment in Renton planned to extend along the Lake Washington shoreline near the Boeing Plant. The unfinished trail segment lies between the Hyatt Regency Hotel on the adjacent parcel to the east of the Boeing Plant site and the Cedar River Trail Park to the west of the Boeing Plant (see Exhibit 20). The planned route for the unfinished segment includes an overwater trail stretching between the Renton Rowing Club dock and the DNR property, then over land on the DNR property, extending across the northeast corner of Boeing Apron R, to where it connects to the easements on the Hyatt Regency site. In order to construct the trail across the section of Boeing property that extends into the lake, the City of Renton obtained an easement from Boeing in 1992 for a nearly 30-foot wide trail connecting the Rowing Club Dock with the DNR property. In 1996, the two parties amended agreement and relocated the easement so as to remain over water but to shift the location to a route directly adjacent to the bulkhead associated with Apron R (see Exhibit 20). In order to mitigate for the approximate 11,000 sq. ft. of lake fill proposed as part of the expansion of Apron R, the applicant has proposed mitigation along the Apron R bulkhead in Area 1. Mitigation proposed includes the addition of a sloped fish habitat enhancement area and a 10 foot wide riparian habitat zone adjacent to the Apron R bulkhead. As proposed, the mitigation would be located within the existing trail easement and would impede the ability of the City to exercise its right to construct the last remaining section of the Sam Chastain Trail. In order to ensure that the City retains the ability to construct this critical linkage, staff recommends as a mitigation measure that the applicant agree to relocate the overwater easement to the original location as depicted in the King County Record #9209171541 (see Exhibit 20) which would move the trail outside the proposed mitigation site. The proposed construction of a stem wall in Area 2 on the east side of the property would also impact the City’s ability to make the trail connection and provide recreational access to Lake Washington via the Sam Chastain Trail. Proposed construction in Area 2 includes the raising of the northeast corner of the apron in order to direct surface water to new a stormwater conveyance system. The proposed grade change and associated retaining/stem wall would impact access to the shoreline and could impede public access to Lake Washington as required by the Shoreline Master Program Regulations in RMC 4-3-090. In order to preserve public access to Lake Washington and the opportunity to complete a planned regional trail connection, staff recommends as a mitigation measure that the applicant grant the city a 10-foot access easement between the proposed new stemwall and east property line. Mitigation Measures: 1) The applicant shall work with the City to relocate the existing easement (Recording #9609040765) to the location of the original easement (Recording #9209171541) or another location approved by Community Services Department. The relocated easement shall be recorded prior to Construction Permit issuance. Alternatively, the applicant could proposed to incorporate the trail design into the mitigation plan and build the trail in the location of the existing easement as a part of the Apron R construction permits. 2) The applicant shall grant the City a minimum 10-foot wide public trail easement running parallel to the entirety of the proposed stem wall on the east side of property. The easement shall be reviewed and approved by the Community Services Department and the City Attorney’s Office. Once approved the easement shall be recorded prior to construction permit issuance. Nexus: SEPA Environmental Review, RMC 4-3-090 Shoreline Master Program Regulations, Trails and Bicycle Master Plan, Chastain Waterfront Trail Plan. E. Comments of Reviewing Departments The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments have been incorporated into the text of this report and/or listed under Exhibit 21 “Plan Review Comments to Applicant.” DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD City of Renton Department of Community & Economic Development Environmental Review Committee Report BOEING APRON R INFRASTRUCTURE MAINTENANCE AND REPAIR LUA17-000631, ECF Report of December 14th, 2017 Page 15 of 15 ERC REPORT 17-000631  Copies of all Review Comments are contained in the Official File and may be attached to this report. The Environmental Determination decision will become final if the decision is not appealed within the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Environmental Determination Appeal Process: Appeals of the environmental determination must be filed in writing together with the required fee to: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057, on or before 5:00 p.m. on January 5, 2017. RMC 4-8-110 governs appeals to the Hearing Examiner and additional information regarding the appeal process may be obtained from the City Clerk’s Office, Renton City Hall – 7th Floor, (425) 430-6510. DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD Goals: - Left turns only at major intersections for pedestrian safety. - No staging area. Proposed Ingress and Egress Route Page 43 - Trucking Route Page 42 of 61 Page 42 - Trucking Route EXHIBIT 28 DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD 38'-6" 60'-0" Security Guard Shack. Power to be provided. Rolling SecurityGate Closed Position Existing CB Rim (ELV-99.75') 10'-0" POC 10' South of existing MH 75' - 12" DI STS Culvert Insert 1:2 Slope max 1:2 Slope max POT Relocate PEDESTRAIN Xing Sign & Bollards New stripe TBM EL 100.0' (Valve Access Rim) ELV-99.94' ELV-99.95' ELV-98.36'ELV-98.36'ELV-98.37 ELV-98.36'ELV-98.33'ELV-98.36' ELV-98.35' ELV-98.33' ELV-99.35'ELV-99.62'ELV-99.81'ELV-99.82' ELV-99.85' ELV-99.87'ELV-99.84' ELV-99.80' ELV-99.92'ELV-99.35' ELV-99.91 ELV-100.07' Existing CB Rim (ELV-99.83') ELV-97.03'INV ELV-97.04'INV ELV-97.18'INV ELV-97.24'INV ELV-97.99'INV ELV-97.03' Gate Work Plan Rock and asphalt infill Gate Fence Post Gate Fence Post Rolling Security Gate Open Position Space allocated for two Boeing Security Parking Stalls Remove current motorcycle parking 33'18' Space allocated formotorcycle parking Page 40 – Temporary Construction Entrance Design Page 40 of 61 EXHIBIT 29 DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD Page 41 - PBS Engineering – Preliminary Culvert Design Page 41 of 61 EXHIBIT 30 DocuSign Envelope ID: 9B3ABBC7-4311-4A8C-98AE-C14FB8F9C4DD