Holiday closure Monday May 28: Most county offices will be closed in observance of Memorial Day.

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King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-684-1280
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

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Puget Sound shoreline next to the West Point Treatment Plant, Seattle

Alternative means for Combined Sewer Overflow Control in the South Magnolia basin

Alternative means for Combined Sewer Overflow Control in the South Magnolia basin
Location of alternative means for CSO control in South Magnolia basin

In 2008, King County reported that the South Magnolia CSO facility has 19 overflows per year on average that discharge a total of 31 million gallons into Puget Sound from the outfall off South Magnolia. Alternative means being considered must be capable of managing a volume of about 1.8 million gallons of peak flows in order to meet regulatory requirements.

Information about proposed alternatives for CSO control projects in South Magnolia is provided below, including some of the benefits and challenges King County has identified for each alternative.

32nd Ave W (underground storage)32nd Ave W to 23rd Ave W (conveyance and underground storage)32nd Ave W to Interbay Pump Station (conveyance and storage)

View recommended proposal
Recommended proposal for the South Magnolia CSO Control Project