North Beach CSO Control Project
March 19, 2015 Update
Concrete work for the combined sewer overflow (CSO) tank is almost complete. Crews are continuing to backfill the area above the CSO tank (adding dirt and gravel) and installing interior equipment and the roof for the mechanical/electrical building.
View construction update (March 19, 2015) and construction photos.
View project newsletter (February 2015).
-- Project milestones and activities for 2015
-- What will the project area look like when construction is complete?
-- North Beach Elementary students learn about CSO control!
Keep up to date on construction plans and activities
• Work in the right-of-way
• Work on King County’s property
• Traffic control
North Beach Pump Station, located on King County property next to Blue Ridge Park, is built on the footprint of the former City of Seattle treatment plant.
King County is building an underground storage tank in the right-of-way in N.W. Blue Ridge Drive and Triton Drive N.W. This facility will be able to store to 380,000 gallons of untreated water during peak flows when the North Beach Pump Station reaches maximum capacity.
Learn more about the project area and elements.
Why does King County need to do this project?
In 2008, King County reported that the North Beach combined sewer overflow facility had 10 overflows per year on long-term average that discharge a total of 2.2 million gallons into Puget Sound off North Beach. At North Beach, King County is working to meet current regulations set by the Washington Department of Ecology require no more than one untreated discharge per year on a long term average.
King County appreciates your patience as we continue building this mandated project.
Intersection closure update. King County's contractor, Stellar J Corporation, modified the work plan to avoid additional time needed to reopen then close the intersection of N.W. Blue Ridge Drive and N.W. Triton Drive. They will now open the road in early June for limited vehicle and pedestrian traffic while work adjacent to the road is completed. The road is expected to fully reopen by the end of July.
Project milestones and activities for 2015. Source: Project newsletter, February 2015
Understanding the sewer system in North Beach
The North Beach Pump Station has provided wastewater service for the area since 1962 by collecting flows from the City of Seattle’s local sewer system. These flows are conveyed to the Carkeek Wet Weather Facility where they are either pumped to the county’s West Point Treatment Plant or, in large storm events, treated on site. The North Beach Pump Station is built on the footprint of what was once a City of Seattle treatment plant. The walls and foundation are from the original treatment plant.
Learn more: download Understanding the sewer system in North Beach, Winter 2014
Did you know?
- The North Beach Pump Station is built on the footprint of what was once a City of Seattle treatment plant. The walls and foundation are from the original treatment plant.
- When Metro was created by voters in 1958 to provide regional wastewater conveyance and treatment, local treatment facilities like the one in North Beach were considered for conversion to pump stations to bring flows to regional treatment facilities.
- The current service area for the North Beach Pump Station is 633 acres. Wastewater from additional areas within Blue Ridge are conveyed by gravity to the North Beach force main, where they combine with pumped flows to the Carkeek Wet Weather Facility.
- The North Beach Pump Station is largely built underground with access hatches and ventilation equipment above ground. Four pumps are used to convey up to 3 million gallons per day (mgd) of wastewater to Carkeek.
- The CSO facilities include a deepwater outfall upgraded in the 1970’s from the outfall that served the original treatment facility. Discharge to a second outfall, which usually conveys stormwater, helps to prevent backups into homes in large storms.
- The new CSO facility will introduce odor control at the North Beach site. Currently there is no odor control associated with the North Beach Pump Station. King County has not received odor complaints about this facility.