SR 539 - Fourmile Creek Mitigation Site - Complete November 2020


In summer 2020, contractor crews with Matia Contractors working for the Washington State Department of Transportation rehabilitated existing wetlands in the area of Fourmile Creek southeast of State Route 539 where it intersects with Ten Mile Road.

This project mitigates the potential environmental impacts expected to result from highway construction, including the I-5/Northbound on-ramp at Bakerview Road and the future I-5/Slater Road improvements.

Needs & Benefits

Mitigation work increases the size of the existing wetlands and help reconnect Fourmile Creek to its natural floodplain. Adding large logs and root wads to the wetland buffer protects water quality in the restored area. Over time, these improvements and reconnections of waterways will help with flood control and expand habitat for native species such as salmon. Mitigation work also included clearing and grubbing, earthwork, canary grass removal, planting and seeding.


  • Spring 2020: Advertised for competitive bidding.
  • July 2020: Contract awarded to Matia Contractors
  • Summer 2020: Construction scheduled to begin.
  • Fall 2020: Construction scheduled to be complete.


This $589,514 project was funded by the Connecting Washington Account (CWA).


Melissa Ambler
Project Engineer

Thumbnail map of Fourmile Creek mitigation site