Project overview
Reconnecting waterways where roads act as barriers is a priority for the state. In western Washington, this means building hundreds of fish-passable structures under state highways to create habitat that is essential for meeting fish recovery goals.
Three culverts in the interchange of Interstate 5 and State Route 104 in Mountlake Terrace are a barrier to fish migration through McAleer Creek and an unnamed tributary to McAleer Creek, which drain into Lake Washington. This project will replace the culverts and rebuild the stream to reopen habitat and restore salmon populations. As early as summer 2026, a Design-Builder working for WSDOT will begin installing new fish-passable structures that convey McAleer Creek under Interstate 5.
What to expect
WSDOT will select a qualified design-build contractor to complete the design of the fish-passable structures for McAleer Creek under I-5. This project is fully funded and combined into a single contract with other fish passage projects on SR 522 and SR 524. Construction is currently anticipated to begin in mid to late 2026 and interstate closure needs will be determined by the type of structures and construction method proposed by the Design-Builder. Lane reductions on I-5 are expected to be necessary during select periods of construction to build the new culvert structure under I-5.
While the timing of culvert construction largely depends on the Design-Builder, we anticipate construction could occur periodically over the span of 2 to 3 years. The exact dates and details of travel impacts will be announced closer to the start construction.
As work progresses, we will post important project updates to our social media channels and our weekly GovDelivery e-newsletters.
This project will build three new fish passages at crossing centered around the I-5 interchange with SR 104 located in Mountlake Terrace, WA.
