Thursday, June 18, 2020

SR 530 east of Arlington shifts to bypass so we can replace culvert for Trafton Creek

By Tom Pearce

Next week we'll shift State Route 530 traffic east of Arlington for the second part of our Schoolyard and Trafton Creek fish passage project. On Thursday, June 25, our contractor, Kiewit, will move both directions of traffic onto a single-lane bypass between Arnot Road and Kroeze Road.

People who travel this section of SR 530 during the next few months will find temporary traffic signals controlling the single-lane bypass. You'll want to allow an extra 5-10 minutes if you're traveling through the area.

This work is similar to a bypass we put in at Schoolyard Creek last summer. That bypass was shorter and allowed us to replace an old, narrow culvert under the highway. The new culvert makes it much easier for resident and migratory fish to travel up and downstream.
The new Schoolyard Creek culvert under SR 530 provides a natural creek bed, which allows
migratory and resident fish to continue farther upstream.

Trafton Creek
The bypass will be in place much longer this year because Trafton Creek is more than 40 feet below SR 530. That's a lot of material to dig up before we remove the existing culvert and replace it with a new one that's 26 feet wide.
Now Trafton Creek comes out of a pipe culvert. Fast-moving water prevents fish from traveling upstream. A new large box culvert will allow fish to get to an additional 3½ miles of habitat.

There's a big drop from the existing culvert and water travels too quickly, preventing fish from traveling upstream. With the new culvert, we will add a more natural creek bed, which will allow coho salmon, steelhead, bull and sea-run cutthroat trout to travel an additional 3½ miles of spawning and rearing areas upstream.

Importance of improving fish passage
Increasing habitat for salmon and other fish is important to the commercial and recreational fishing industries, as well as for marine life, like orcas that depend on them for food.

Improving fish passage is also something we need to do following a 2013 U.S. District Court ruling that requires us to remove culverts under state highways that are a barrier to fish passage. This ruling affects almost 1,000 culverts in western Washington. We've already done hundreds of these projects, but we need to make significant progress toward this goal during the next 10 years.

Replacing these culverts at School Yard and Trafton creeks are two significant pieces of that work.