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SR 520 Bridge Program: Eastside Wetland Mitigation - Evans Creek

The Washington State Department of Transportation (WSDOT) is providing wetland mitigation at the confluence of Bear Creek and Evans Creek in the City of Redmond. This work is part of the Medina to SR 202: Eastside Transit and HOV Project.

WSDOT, the City of Redmond, and local watershed groups identified the Evans Creek mitigation site as an important wetland habitat area. The mitigation work will strengthen the local natural environment by improving the quality of wetland habitat. Improvements will mitigate for a loss in wetlands resulting from the construction of the Eastside project.

Why is WSDOT providing mitigation?

Through the environmental review process, WSDOT works to avoid, minimize and mitigate for all project effects. While we have avoided and minimized to the greatest practical extent, construction of the project will result in the loss of approximately 6.3 acres of wetlands in the Eastside project area. To mitigate for these wetland effects, WSDOT is providing improvements at the Evans Creek site.

What will the Evans Creek mitigation project include?

WSDOT is providing wetland mitigation of approximately 32 acres near the City of Redmond. This mitigation is occurring on land that was previously farmed. WSDOT will monitor this site and collect data on plants, wildlife, soil and water for up to 10 years to ensure the site is compatible with and contributes to the local ecosystem.

How have resource agencies and tribes been involved in this mitigation project?

The project team worked with resource agencies and tribes to identify the Evans Creek site. WSDOT worked with resource agencies and tribes through project design and continued to notify these stakeholders during work on the site.

A view of Evans Creek, looking east
A view of Evans Creek, looking east

What are the ecological benefits of the mitigation project?

Evans Creek and Bear Creek contain Cedar River, Issaquah and North Lake Washington Chinook salmon populations. In fact, Bear Creek has the highest abundance of Chinook salmon of all Northwest tributaries.

The Evans Creek mitigation site will support a variety of wetland plants and wildlife. Native plants will provide better habitat than the nonnative reed canarygrass that had taken over this area, and will improve water quality and benefit salmon and other species.

Native wetland plants include dogwood, salmonberry, willow, and native wetland grasses. Other native plant species include black cottonwood, red alder, Western red cedar, and Sitka spruce. The project also incorporated habitat enhancing features such as large and small woody debris.

What is the project timeline?

Work on the site began in summer 2012, and was completed in late 2013. WSDOT anticipates monitoring the site from 2014 to 2024.