Mitigation

In May 2015, the City Council and the Sound Transit Board of Directors agreed to a comprehensive amended Memorandum of Understanding (MOU) that assures the two agencies will coordinate and collaborate during the design and construction of East Link. This MOU contains, among many mutual agreements, general and specific mitigation efforts to address construction impacts to roads, neighborhoods and parks. Exhibit O of the amended MOU reflects the various mitigation for the East Link light rail project.

Noise Mitigation

The City of Bellevue is the first jurisdiction to apply a local noise code to light rail operations and was faced with a challenge in how to apply its regulations to this particular operation.  In addition to operational noise, construction noise needed to be addressed.

Bellevue’s Noise Control Code

Bellevue’s Noise Control Code (Noise Code) regulates and establishes permissible noise levels based on the type of land use (e.g. residential, business or commercial). The code also sets daytime noise levels in residential areas at a maximum of 55 dBA (decibel level) and nighttime (between 10 p.m. and 7 a.m.) at a maximum of 45 decibels.  Construction noise is allowed between 7 a.m. and 6 p.m., Monday through Friday and 9 a.m. to 6 p.m. on Saturday, but is prohibited beyond these hours, on Sunday, and on certain holidays. The Noise Code does contain exemption provisions.

East Link Operational Noise and Mitigation

The East Link light rail facility is a permitted use under Bellevue’s land use code and its construction (including the guideway system and supporting infrastructure) is governed by the Design and Mitigation Permit (D&M Permit) process. A D&M permit has been issued for:

Noise from the operation of light rail is expected from a number of components of the system:

  • Light rail vehicle operation noise: The noise of a train travelling by a location including wheel/rail interface, train-mounted warning devices, and track cross overs.
  • Stationary noise: The noise of the safety systems associated with the train including pedestrian-audible warning systems at stations, station public address systems, electrical transformers, and traction power substations.

The City’s Noise Code anticipates regulating noise from stationary noise generators but includes exemptions for safety features.

Because the City’s code does not take into account how to deal with ambient noise levels above the allowed threshold, and additionally is fashioned to deal with stationary noise sources, the City engaged a consultant to assist the City in determining how to apply the code to Sound Transit’s operational noise, and determine the appropriate mitigation.  The City’s consultant primarily reviewed studies conducted by Sound Transit to ensure that industry best practices were followed in developing the noise models, interpreting the outcomes and fashioning mitigation.

These studies concluded the level of ambient nighttime noise in South Bellevue exceeds what the City’s code allows. Ambient noise is the level of typical existing noise from all sources.  In the South Bellevue area ambient noise is due to everyday traffic noise from I-405, I-90 and 112th Avenue NE.  The city’s consultant reviewed Sound Transit’s reports and proposed additional mitigation, such as extensions in length and height of sound walls, maintenance of rails and train vehicles, and nighttime reduction of any audible warnings (such as bells or announcement).  This additional mitigation is designed to ensure that East Link’s operational noise does not increase the ambient noise levels in residential areas and is addressed in the E320 D&M Permit.

Additionally, the city is requiring monitoring of the light rail system to ensure operating sound levels are consistent with projections made through the environmental and permit review process. This monitoring ensures that these sounds do not become louder over time because of lack of maintenance.

East Link Construction Noise and Mitigation

Construction noise from East Link and other commercial construction projects is regulated by defined hours of the day where construction can occur -- between 7 a.m. and 6 p.m., Monday through Friday and 9 a.m. to 6 p.m. on Saturdays.  Requests for “extended work hours” (permission to work outside of these windows) are routinely requested for commercial projects, and are granted in consideration of special needs for the project.

Approved Expanded Exempt Hours Permits

The City has approved the following Expanded Exempt Work Hours Permits

  • Central Bellevue (Permit 17-102696)
    • Long span aerial guideway over I-405 from NE 6th Street to 116th Ave NE. Work anticipated to occur in 10- to 12-hour shifts, varying in times with 24-hour days and up to 24 months. Maximum noise level is 78 dBA
    • Across NE 8th Street along BNSF railroad. Work is anticipated to occur in 10- to 12-hour shifts varying in time within 24-hour day and for approximately one (1) month. Maximum noise level is 58 dBA.
  • BelRed (Permit 16-145773 LY)
    • Elevated guideway over Kelsey Creek. Construction in the area of 124th Ave NE to 130th Ave NE for 24 months. Work anticipated to occur in 10- to 12-hour shifts. Maximum noise level is 58 dBA.
  • South Bellevue: (Permit 15-124380 LY)
    • East Channel Bridge to the south end of the South Bellevue light station. Work is anticipated to occur in 10 to 12-hour shifts (during 24-hour period) for a 39 months. Maximum noise level is 77 dBA
    • North of the South Bellevue station to the “Wye” at 112th Avenue SE. Work is anticipated to occur from 7 a.m. to 10 p.m. on weekdays and from 7 a.m. to 9 p.m. on weekends for 34 months. Maximum noise level is 80 dBA.
    •  Note: A supplemental permit (17-114040 LY) was issued to allow for the installation of pre-cast tub girders for the light rail guideway to occur within the South Bellevue Station site. This permit covers the anticipated operations from January 2018 through January 2019.
    • View Sound Transit graphic of Expanded Work Hours Permit by construction zones.
  • Tunnel (Permit 15-122917 LY)
    • To complete downtown Bellevue tunnel on a continuous 24-hour cycle using sequential excavation method for 52 months.  

Traffic Mitigation

The city is aware of the importance of Bellevue Way as the south entrance to and from the city. While no large-scale construction project of this magnitude is without disruption, requirements for the flow of traffic along Bellevue Way during construction are of paramount importance. 

Bellevue Way

The 2015 MOU requires that two lanes of traffic on Bellevue Way must be maintained in the peak direction at all times. This results in maintaining existing travel lanes in the direction necessary during peak commute times, meaning two lanes northbound, into Bellevue during the morning commute, and two lanes southbound, toward I-90, during the evening commute. Lane closures outside of peak travel times (7-10 a.m. and 4-6 p.m.) and full weekend closures will also be necessary for certain work. It is possible that more than 20 full weekend closures will be needed over the four-to-five-year construction timeline.

In response to the public desire to avoid having audible signals at rail/road crossings on Bellevue Way at Southeast Fourth Street and Southeast First Place, it was determined that the streets would be permanently closed. Beginning in the spring, the Southeast First Place entrance to Surrey Downs will be permanently closed. The permanent closure of Southeast Fourth Street is expected in spring 2017.

South Bellevue Park and Ride Closure

Sound Transit anticipates the closure of the South Bellevue Park and Ride (P&R) to last five years. Per the 2015 amended MOU, the agency must implement, in consultation with the city, “alternate parking and transit access” for those commuters who use this P&R 60 days prior to the closure. As the closure is expected around late fall 2016, a parking mitigation plan is not expected until around early fall. However, it is anticipated that some tools Sound Transit will implement include alternate commuter parking locations and route revisions. Sound Transit and the city will communicate the parking mitigation plan to the community.

Sound Transit’s 550 Route (Bellevue to/from Seattle) will continue to serve commuters during East Link construction but will be eliminated once the East Link extension is in full operation (anticipated in 2023).

Neighborhood Traffic Mitigation for South Bellevue Segment

In April 2016, the city hosted a meeting with residents of the Enatai, Surrey Downs, Bellecrest neighborhoods and Beaux Arts Village to share background on known areas of traffic conditions and constraints, to receive additional feedback on other areas of concerns as they relate to East Link construction, and to address the next steps to form the South Bellevue East Link Construction Neighborhood Traffic Mitigation Committee (NTMC).

The NTMC includes a broad and geographically balanced representation from these neighborhoods Members includes one representative of the Board of these south Bellevue neighborhoods and seven “community-at-large” members.

The NTMC has been working to identify and support mitigation tools that best mitigate neighborhood traffic impacts resulting from 112th Avenue Southeast lane closures, reversible lane configuration on Bellevue Way and closure of Bellevue Way Southeast on weekends. The committee has been looking at the overall current traffic conditions and recommending ways to sustain efficient and effective traffic flow in South Bellevue neighborhoods once East Link construction is underway. Exhibit P of the 2015 amended MOU identifies some possible strategies.

Neighborhood Traffic Mitigation Committee Meeting Summaries and Presentations

The greatest concern expressed by residents in these neighborhoods is the increase of cut-through traffic. While not all cut-through traffic can be eliminated, it is anticipated that the work of the NTC will result in a set of tools to minimize and to better safely manage neighborhood traffic.

Park Mitigation

The final East Link alignment selected by the Sound Transit Board is adjacent to Mercer Slough Nature Park and Surrey Downs Park. Both city parks will be impacted by the East Link project and there are mitigation plans in place to offset those impacts.  These impacts and conceptual mitigation have been part of the discussions around this project since preparation of the Draft Environmental Impact Statement (EIS), Final EIS and federal Record of Decision for the project, issued in 2011.

Mercer Slough Nature Park

Enhancements and mitigation to Mercer Slough Nature Park include over six acres of wetland and wetland buffer restoration within the park and planting more than 2,800 trees to offset the 691 being removed for the project.  Additionally, six acres were added to the park through acquisition of private property just south of the Mercer Slough Environmental Education Center.  Following construction of East Link, a new building and parking area will be opened near the Winters House providing park restrooms and u-pick blueberry and seasonal farm-fresh produce sales.  These will be connected to 700 linear feet of new boardwalk trail.

Surrey Downs Park

Once the East Link alignment was finalized, it was necessary to update the city's Surrey Downs Park Master Plan (adopted in 2009) because of the loss of a portion of the Surrey Downs Park along 112th Avenue Southeast frontage. Through a public involvement process, the vision for the park is now to be more neighborhood-focused and will include open grass areas, playgrounds, picnic shelters and a pedestrian “overlook” integrated into the trail system.

Noise studies were conducted and sound mitigation was included in the 112th Street park frontage improvements and the Parks Department will work with adjacent property owners to construct perimeter fencing along the parks boundary with neighbors.

Additionally, vehicle access will be off of Southeast Fourth Street (and no longer 112th Avenue). The council adopted the Surrey Downs Park plan update in November 2015 (park plan schematic). It is expected the Surrey Downs Park improvements will not be initiated until after Sound Transit completes its 112th Street frontage improvements. Current timelines expect park construction to begin in spring 2018.

Contact

Marie JensenCity of Bellevue East Link Outreach

Telephone

425-452-2064

Email

mjensen@bellevuewa.gov

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