US 97 - Boundary Bridge - Remove Fish Barrier

Project news

Traffic has been shifted to a bypass lane.  This lane does not have a shoulder and there is a 12 ft. width restriction and reduced speed zone.  Progress and traffic impacts will be updated weekly on the WSDOT North Central Region Construction Update and Travel Advisory when the project resumes in spring 2020.

Needs & benefits

The current culvert on Swauk Creek is a barrier to salmon and trout due to its size - a 6-foot by 9-foot oval – with a 4-foot drop from the outlet down to the creek bed. It is by the Swauk Creek Campground about 5 miles south of the Blewett Pass Summit (MP 159.67) In Kittitas County.

Replacing the culvert with a concrete bridge opens up valuable spawning and rearing habitat to steelhead, cutthroat, and rainbow trout, as well as providing safe passage under the highway for animals such as elk.

We’re working in partnership with the Mid-Columbia Fisheries Enhancement Group, for additional stream restoration work to improve floodplain connectivity, fish habitat and restore vegetation.


Construction began March 9, building a bypass travel lane on a widened shoulder.  No full closures of the highway are planned. Expect a posted speed reduction through the work zone. Flaggers will be used to control traffic as needed - no more than 20 minute delays.  Some work might require limited overnight flagging, as well.


This project is funded through the WSDOT Capital Improvement Environmental Retrofit program (I-4) to remove fish barriers under state highways. A contract was awarded to Nisqually Construction Services, LLC on November 16, 2018 for $4,244,497.84.


Brian Pearson, Project Engineer 509-667-2880

Location of the culvert being replaced south of Blewett Pass

Photo of the culvert that's been blocking fish passage