North Beach CSO Control Project

How will the new CSO facility work?

• Flows during dry conditions or light rainstorms
• Storage during large storm events
• Flows after large storm events 

Under normal operations, the combined sewer system sends flows directly to the North Beach Pump Station for conveyance to the Carkeek Park Wet Weather Facility where it is either treated or sent on to West Point for treatment. The CSO diversion structure and pipeline storage are bypassed.

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During large storm events, flows up to three million gallons per day (MGD) continue to the North Beach Pump Station but excess flows travel over a weir in the underground diversion structure to the underground storage pipe.

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Once the storm is passed and water levels return to normal, the stored flows are sent back through the North Beach Pump Station and on to the Carkeek Park Wet Weather Facility for conveyance to the West Point Treatment Plan or on site treatment, depending on capacity.

Once the CSO storage facility is in service, people will see one or two crew members on site about once a week for inspection and maintenance. After a storage event, more crew members may be on site to empty and flush the facility. Every three to five years, one to two days of major maintenance will be required, resulting in partial street closure. Advance notice will be provided for maintenance activities that cause traffic disruptions.

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