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Project Spotlight: South Park Pump Station

Street flooding on 5th Ave S.

Seattle Public Utilities began construction in late August on the new South Park Pump Station, to improve chronic flooding and drainage issues in the northern industrial area of Seattle’s South Park neighborhood.

This area experiences chronic flooding for a few main reasons:

  • Stormwater can’t drain during high tide
    South Park is located along the Lower Duwamish Waterway. When it rains, stormwater (rain that runs off roofs, streets, parking lots, and other hard surfaces) is transported through a main pipe into the waterway. To protect the drainage system from river water, a valve closes when the tide is high. When that valve is closed, stormwater can’t drain out to the waterway, so water backs up, sometimes flowing out of inlets and catch basins and flooding the neighborhood.
  • Some streets in the area don’t have a drainage collection system
    When there’s nothing for stormwater to drain into, it floods the streets instead.
  • Many private properties don’t have drainage pipes connected to the main system
    Stormwater on these properties has nowhere to go, so they end up flooding.

The South Park Pump Station is a key first step in addressing these problems. The pump station will help move stormwater to the Waterway when the tide is high and the main pipe can’t drain by gravity. In doing so, the pump station will reduce flooding on roads that have a formal stormwater collection system (including pipes, catch basins, and inlets).

South Park Pump Station design

What’s Next?
The South Park Pump Station is part of a trio of projects that will work together to improve stormwater-related flooding in South Park and help improve water quality in the Duwamish. The other two projects are the South Park Drainage and Roadway Partnership, in which SPU and the Seattle Department of Transportation will improve streets and construct a drainage system in roadways that don’t have one; and a new Stormwater Quality Facility to treat stormwater from the system before it flows into the Waterway.

Learn more about the Pump Station Project and other work in South Park at