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Brandon St. Regulator Station Overflow Sediment Remediation Project

Information about King County’s project at the Brandon St. Regulator Station (RS) Overflow to address historical sediment contamination near County combined sewer overflow (CSO) outfalls.

The County's 1999 Sediment Management Plan evaluated remediation strategies for correcting hazards caused by contaminated sediments near seven King County combined sewer overflows (CSOs). The Brandon St. Regulator Station (RS) Overflow is one of these sites.

The cleanup of the area near the Brandon St. Regulator Station Overflow will happen as a part of the Lower Duwamish Waterway Superfund project. The Lower Duwamish Waterway represents the last five miles of the river before it splits to flow around Harbor Island and out to Puget Sound.

The County is also undertaking source control actions in the drainage basins to identify, trace and reduce chemical inputs to the waterway. The County’s work to control overflows from the County's Brandon and Michigan CSOs will also contribute to keeping the waterway clean.

Brandon St. Regulator Station Overflow

Aerial map displaying location of Brandon Street Regulator Structure Overflow Discharge Point

Brandon Street Regulator Structure Overflow Discharge Point

The Brandon St. Regulator Station sends wastewater flows from the Brandon St. Trunk to a pipe called the Elliot Bay Interceptor (EBI), which runs along the East bank of the Duwamish Waterway. During heavy storms, stormwater can fill up the sewer pipes, sending polluted runoff and sewage through a pipe into the Waterway.


Georgetown Wet Weather Treatment Station

Birds eye rendering of the Georgetown Wet Weather Treatment Station

The Georgetown Wet Weather Treatment Station, located at the corner of 4th Avenue and South Michigan Street in Seattle’s Georgetown neighborhood, can treat up to 70 million gallons of combined rain and wastewater a day that would otherwise discharge directly to the Duwamish River during heavy storms. Before the station was completed in 2022, heavy rains would fill up the area's sewer pipes, sending polluted runoff and sewage through a pipe into the river. 

Aerial map displaying location of the Brandon Street Regulator Structure Overflow Discharge Point

Three elements make up the Georgetown Wet Weather Treatment Station: the processing facility, pipes that connect the facility to the river, and a new outfall structure that releases clean water into the Duwamish River.

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