Fremont Siphon replacement project
May 2013 Update
King County is building a new odor control facility at the County’s site in Fremont as part of the Fremont Siphon Replacement project. Community input helped designers develop the landscape and architectural elements of the site. The building look echoes historic Fremont while the landscape evokes the Northwest Coast. King County’s project team is currently finalizing the project design, acquiring permits and planning for construction. Construction is anticipated to begin in the second half of 2014. To learn more, view project Spring newsletter (PDF).
Project areas in Fremont and Queen Anne.
Fremont Siphon service area
Building the Fremont Siphon Tunnel, 1913. Photo provided by Seattle Municipal Archives (external link)
King County is planning to replace the existing Fremont Siphon, a wastewater conveyance system that extends from Fremont to Queen Anne under the Lake Washington Ship Canal. King County will install new pipelines in a separate crossing under the Ship Canal, just west of the existing siphon. After reviewing a range of options to rehabilitate or replace the Fremont Siphon in 2010, King County recommended replacing the existing pipelines in a new location to reduce potential project risks and impacts, to maintain operations during construction and to provide safe, reliable service for years to come. The County will still retain the existing space in the Fremont Tunnel for Wastewater Treatment Division uses.
Why does King County need to do this project?
The Fremont Siphon is a critical conveyance line that carries wastewater from the county’s northeastern service area to the West Point Treatment Plant. The Fremont Siphon conveys wastewater from a service area of about 60 square miles year round, with an additional area of about 54 square miles during the summer. The siphon pipelines, which may convey up to 220 million gallons per day during storms, are located under the Lake Washington Ship Canal, west of the Fremont Bridge. The siphon was installed in the early 1900’s and has provided wastewater conveyance service for almost 100 years.
View upcoming community meetings and more detailed project schedule.
How King County works with the community during project design
During project design, King County will provide the Fremont and Queen Anne communities with information on project details including:
The public can inform the County’s work by learning about the project and helping to identify reasonable solutions for construction impacts such as traffic disruptions.