I-90 - North Fork Issaquah Creek Fish Passage


January 2018

  • The remaining work includes finishing the rechanneling of the streams and planting.
  • Bid awarded to Scarsella Bros., Inc.
  • Construction began in May 2017.
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WSDOT is realigning North Fork Issaquah Creek near East Lake Sammamish Parkway. The creek crosses the Front Street on- and off-ramps from I-90 twice but will be rerouted north to flow underneath East Lake Sammamish Parkway. A box culvert will be installed at the new creek location underneath East Lake Sammamish Parkway. A second culvert will also be built underneath the highway to give the local migratory trout and salmon additional access to a nearby offshoot of North Fork Issaquah Creek. This project will open up almost a mile of additional fish habitat when completed.

The work will require a full six-day closure of East Lake Sammamish Parkway at the project site and lane closures on the Front Street on- and off-ramps.

Why is WSDOT realigning this section of North Fork Issaquah Creek and replacing a culvert?
The existing culverts are a barrier to fish. Water flows are occasionally too low or strong for fish to navigate upstream. Moving the creek so it crosses the highway once and installing a wider culvert will allow the creek to flow more naturally under the highway and improve the fish habitat in the area. The fish passage project is one of about 1,000 culverts across the state that are mandated to be replaced. In 2013, the U.S. District Court for Western Washington ruled that the state must remove culverts that block fish passage under state highways.

The End Result
Rerouting North Fork Issaquah Creek near East Lake Sammamish Parkway and installing a new culvert will help restore the creek bed to a natural state and improve fish passage for local migratory fish, in compliance with the U.S. District Court ruling.

Project Benefits

  • This project will improve fish passage and open up additional fish habitat.
  • The work will help WSDOT comply with the U.S. District Court ruling regarding fish passage.

What is the project timeline?

  • February 2017: Project advertised for competitive bidding.
  • March 2017: Project awarded to Scarsella Bros, Inc.
  • June 2017: Construction begins.
  • Fall 2017: Construction is scheduled to be completed.


Financial Data for PIN 109058B
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $7,675
CWA $0
Total $7,675


How can I get more information?

Marqise Allen
WSDOT communications
Phone: 206-440-4699
E-mail: allenmq@wsdot.wa.gov