Seattle Public Utilities Mami Hara, General Manager/CEO

South Park Pump Station


Current design of the flood control pump station.


The northern industrial and residential area of South Park experiences chronic flooding for three reasons:

  • The main drainage pipe to the Lower Duwamish Waterway is underwater during high tide.
    When it rains during high tides, the main pipe in 7th Ave S that flows to the Duwamish Waterway cannot drain out to the river and water backs up in the drainage system. Rain falling in the lower areas of the basin cannot flow out, and water in the main pipe can sometimes flow back out of inlets and catch basins, flooding the neighborhood. A pump station will allow the main pipe to drain during high tides and relieve flooding in areas that have a drainage system in place.
  • Not all streets in the area have a drainage collection system.
    Additional drainage improvements will not be fully effective until the pump station is installed so that the pipes can drain at high tide. When additional roadway drainage is built in the future, it will connect to the main pipe in 7th Ave S and the pump station will allow the system to drain when the tides are high.
  • Many private properties in the basin do not have drainage pipes connected to the public drainage system.
    Some properties are lower than the street or there is no existing street collection system. In these areas, individual property owners may need to make site improvements and connect to a public drainage system in the street when one is available.

Project site

The site for this project was selected because of its location on the main stormwater drainage pipe where it empties into the Duwamish Waterway. The facility is planned to be located near the intersection of 7th Avenue S and S Riverside Drive.

The project will have underground equipment and above-ground structures, including a small electrical controls building and a concrete structure, about 12 feet tall, 50 feet wide and 110 feet long. The facility will be fenced for security and will have security lighting. It will be operated remotely so staff will only visit the site periodically to check and maintain the pump station.

Project history

The pump station is designed to be built where the 7th Ave S meets the Duwamish River. SPU has petitioned the Seattle Department of Transportation to vacate the 7th Avenue S street-end to make way for construction of the pump station and is assessing alternative options for locating the pump station while the vacation petition is active.


Shailee Sztern
Pump Station project manager
(206) 256-5256

Sheila Harrison
Line of business representative
(206) 684-5899

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