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Construction begins on Magnolia pipeline repair project


Construction on a project to repair a damaged combined sewer and stormwater pipeline in Seattle’s Magnolia neighborhood begins Monday, Dec. 18. The public is invited to learn about the project plans and schedule at an online open house through Jan. 31.


Construction crews working for King County’s Wastewater Treatment Division are mobilized in Smith Cove Park as activity ramps up on a 3,000-foot pipeline repair project in Seattle’s Magnolia neighborhood. 

The work is necessary to fix the pipeline, which failed due to a fractured section of pipe that was discovered by utility crews during an inspection in fall 2016. The damaged section is located about 150 feet beneath the intersection of West Galer Street and Thorndike Avenue. 

With site preparation completed, contractors will now begin excavation to access the pipeline. People are invited to learn more about the project and ask questions at an online open house through Jan. 31.

Repairs will be done using a trenchless construction technique called “pipe bursting”, which uses a machine to pull a new pipe through the existing pipe corridor. Construction activity will also take place along a portion of 32nd Avenue West. 

To complete the project by spring 2018, contractors plan to work weekdays between the hours of 7 a.m. to 6 p.m. The south soccer field at Smith Cove Park will also need to be closed until the project is completed. The public will be notified if evening or weekend work is necessary.

The current pipeline was built in 2015 to operate during heavy rains, directing sewage and stormwater that would typically overflow into Elliott Bay to a 1.5-million-gallon underground storage tank as part of King County’s South Magnolia Combined Sewer Overflow Control Project.

When the new pipeline is completed, it will enable King County to meet its requirements to control these overflows by storing the stormwater and sewage at the Magnolia Wet Weather Facility until it can be treated at the West Point Treatment Plant.

Although King County holds the contractor liable for the cost of the project, the contractor and the county have agreed to reserve their rights on the legal issues and focus on repairs. Both the county and the contractor are pursuing insurance coverage under the project policy.

King County is committed to being a good neighbor and working with community members to address questions or concerns about the project. Additional information is available online or by calling the construction hotline at 206-205-5969.

The online open house can be accessed at