Ballard Siphon Replacement Project will detour traffic starting January 20th
Information provided by SDOT
To protect public health and the environment, King County is building a new 85-inch siphon pipe under Salmon Bay between the Ballard and Interbay areas of Seattle. The new siphon will be installed more than 120 feet underground and connect the Ballard Regulator Station at 5110 Shilshole Avenue Northwest in Ballard to the North Interceptor at West Commodore Way and 24th Avenue West intersection in Interbay (see project map).
After excavating vertical shafts at the Shilshole Avenue and Commodore Way sites, King County’s contractor will install a tunnel boring machine to bore a pipe corridor for the new siphon roughly 60 feet beneath Salmon Bay. The existing siphon will be cleaned out and relined as part of this project. Additional equipment supporting the new pipe will also be installed at the Ballard Regulator.
Project need:
The new pipe is needed to accommodate growth in north Seattle. The new pipe replaces two 36-inch wooden stave pipes which have served the Ballard community since the 1930’s. The new pipe will meet north Seattle’s wastewater conveyance needs through the end of the century.