Mt Loop Hwy MP8 at Cranberry Creek

Description - Completed

Snohomish County Public Works proposed a project to replace an undersized 6-foot diameter aging corrugated metal pipe with a new 20-foot wide concrete water crossing / fish passage culvert. The new culvert will resolve the current trout and salmon migration barrier that was identified at this site. The project will provide an estimated 6-miles of unimpeded fish baring stream as well as 78-acres of stream associated wetlands.

The project will also feature installation of two dozen pieces of large woody debris to help create rearing habitat and resting areas for fish migration. The area guardrail systems will also be updated to meet new Washington State Department of Transportation (WSDOT) standards and wrap around an adjacent driveway to provide added safety for westbound traffic approaching the site.


Construction began in June 2016 and is anticipated to continue through December 2016.

Traffic Impact

To install the new culvert, Mountain Loop Highway near milepost 8 will be temporarily changed to a single lane road, operated as a one-way alternating direction road. Onsite flaggers will direct traffic during working hours, and a trailer-mounted signal will be in effect during nights and weekends.

Commuters traveling through the area should expect delays of up to 20 minutes.

No overweight or oversized vehicles permitted during construction.


The estimated project construction cost is roughly $750,000.

  • 75 percent of the construction costs is funded by the U.S. Department of Agriculture (USDA) Forest Service and the U.S. Environmental Protection Agency (EPA)
  • The remaining 25 percent and any potential overages is funded by Snohomish County

Documents and Maps