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SR 520 Bridge Program: Medina to SR 202 Eastside Project Community and Environmental Improvements

new fish culvert on Eastside 
New Eastside fish culvert under SR 520
Key project benefits

Eastside lid diagrams

Environmental process overview

What are the key project benefits for Eastside communities and the environment?

  • New lids at Evergreen Point Rd, 84th Avenue NE, 92nd Avenue NE and a landscaped overcrossing at Bellevue Way
    We built landscaped sections over the roadway to help reconnect communities divided by the original construction of SR 520 in the 1960s.
  • Noise-reduction techniques
    We built walls along the roadway between Evergreen Point Road and the vicinity of 108th Avenue Northeast to help reduce noise from highway traffic and provide screening for residents living along the corridor.
  • Stormwater detention facilities between Evergreen Point Road and 108th Avenue NE
    We built stormwater detention facilities to improve water quality by retaining, filtering and treating highway runoff before it enters local streams and creeks.
  • Fish habitat improvements
    We made improvements to Yarrow Creek and other streams, and installed larger culverts under the roadway to eliminate potential barriers to fish migration. 
  • Wetlands enhancement
    We made substantial improvements to approximately 32 acres of sensitive wetland area near the confluence of Evans and Bear creeks in Redmond. We did this as mitigation for the loss of about 6 acres of wetlands from construction of the Eastside Transit and HOV Project.


Eastside lids

Click each image to open the lid diagram in a larger PDF.
Evergreen Point Road lid plan. Click to open in a larger PDF.
Evergreen Point Road

84th Avenue Northeast

92nd Avenue Northeast lid plan. Click to open in a larger PDF.
92nd Avenue Northeast 

Plan view of Bellevue/108th Avenue intersection. Click to open in larger PDF.
Bellevue Way / 108th Avenue Northeast


Environmental process

There were six milestones in the environmental review process:

1. Conduct public and agency scoping. During the public and agency scoping phase, we asked for comments from the public, tribal nations, and federal, state and local agencies on the purpose and need for the project and the environmental topics to evaluate during development of the project’s environmental assessment (EA). We held a public scoping meeting in September 2008.

2. Collect data and evaluate effects. The next step was to collect data on the existing conditions of the project area. This included conducting social, cultural, environmental and engineering studies related to the proposed project.

3. Issue environmental assessment. Following data collection, we prepared and published an environmental assessment (EA) in December 2009 that included the results of our analysis and identified ways we could mitigate the environmental effects of the project.

4. Public hearing and comment period. In December 2009, we held a public hearing to gather comments on the results of our evaluation and proposed mitigation measures.

5. Issue Finding of No Significant Impact. In May 2010, we published the Finding of No Significant Impact (FONSI) document, which concluded the environmental process. The FONSI explained the reasons for the project decision and included the mitigation measures that we incorporated into the project. 

6. Secure permits and implement the project. Permits for the project were secured and construction began in April 2011. WSDOT opened the new highway to drivers in late summer 2014, and all project improvements are nearing completion.