November 2012
- We are nearly finished with this work.
- Water and fish including sockeye, chinook and coho are in the new stream.
- KING 5's Gary Chittim did a story about our project.
WSDOT has replaced a 12 foot diameter culvert with a 40 foot diameter culvert that carries the east fork of Issaquah Creek. Issaquah Creek is home to sockeye, chinook, Coho, steelhead, sea-run cutthroat and resident trout.
The 25 foot stream was shoehorned into an eight-foot streambed. This barrier was identified in 2006 as a barrier to fish passage.
The work was made even more challenging by two natural gas pipelines that run through the area. The pipelines are part of a system that carries fuel from Canada to Utah.
Why is WSDOT
replacing the culvert under I-90 at Issaquah Creek?
This narrow culvert made it difficult for salmon and trout to use historic rearing and spawning grounds. It restricted the stream's flow, which increased water velocity and exceeded the swimming capabilities of the fish.
Additionally, there is a 1.8-foot drop in the stream, which is too steep for fish.
State law requires WSDOT to install and maintain culverts to assist fish passage. WSDOT works with the Department of Fish and Wildlife to identify and prioritize culverts that need to be replaced.
The End Result
Replacing the culvert with a wide bridge allows fish to migrate to spawning grounds without a barrier at this location.
The natural gas pipelines will have a concrete support rather than dirt and water.
Project Benefits
Environmental - Removing fish barriers is important to the restoration of fish habitats and salmon recovery efforts.
Safety - Strong culverts also help support the roadways and ensure they’re not undermined by moving water.
What is the project timeline?
- November 2011: Project awarded to the most competitive bidder, Tri-State Construction.
- May 2012: Construction began.
- November 2012: Expected completion.
Financial Information
Project signage will reflect the cost of construction engineering, project bid award and sales tax.
$2.8 million - pre-existing funds
Fifty percent of funding came from Williams Pipeline.
How can I get more information?
Contact:
Jamie Holter
WSDOT Communications
206-440-4698
jamie.holter@wsdot.wa.gov
Hien Trinh
WSDOT Project Engineer
206-768-5601
trinhh@wsdot.wa.gov
back to top