North Beach CSO Control Project
January 23, 2015 Update
Crews had two successful concrete pours in the last week. Most of these pours are for the combined sewer overflow (CSO) tank walls. Soon crews will begin to pour concrete for the top of the tank structure. More concrete pours are planned through February, then they will begin to wind down. Concrete pours are tentatively planned for the following dates:
-- January 23 (48b structure)
-- January 27 (CSO tank wall, 48b structure)
-- January 28 (Mechanical/electrical building)
-- February 3 (CSO tank wall, 48b structure)
-- February 14 (CSO tank wall)
-- February 17 (CSO tank top)
-- February 20 (CSO tank top)
View construction update (January 23, 2015).
View more photos.
What progress have we made? What's next?
Download the Winter 2014 newsletter (PDF).
Intersection to remain closed
King County, the Seattle Department of Transportation, and the County’s contractor have worked together to find an option for uninterrupted work in the right-of-way on the North Beach CSO Control Project. The street will remain closed until early 2015, when a temporary reopening is scheduled for three months. Learn more on the Work in the right-of-way page.
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 designing and 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.
This construction schedule is proposed and subject to change. Detailed construction schedules are being developed by King County’s contractor for the project, Stellar J Corporation.
Project schedule (updated December 2014).
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.