South Park Drainage and Roadway Partnership

What & Why

Seattle Public Utilities is currently working on three stormwater projects in South Park's lower industrial basin. These projects will manage flooding and result in cleaner water and a healthier Duwamish River.

The South Park Drainage and Roadway Partnership project will complete design for a new stormwater collection system in roadways that don't currently have one. Scope and budget will ultimately determine which roads will receive new drainage systems.

We are also planning two additional projects in the lower industrial basin:

  1. A flood control pump station to overcome the flooding effects of high tide.
  2. A water quality facility to treat stormwater from the storm drain system before it flows into the Duwamish Waterway.

The South Park Drainage and Roadway Partnership project is supported in part with funding from the King County Flood Control District.

What’s happening now?

Seattle Public Utilities (SPU) and the Seattle Department of Transportation (SDOT) are designing the South Park Drainage and Roadway Partnership project to construct streets and a drainage system to improve chronic flooding and drainage issues. Stormwater flows will eventually be directed to a future pump station and water quality facility. 

In 2017, we gathered feedback from lower industrial basin businesses and residents on how they utilize the right-of-way, drainage and flooding issues they experience, and SPU's proposed plan. Based on community input and technical feasibility, the project team is moving forward with a design that features sidewalks, curbs and gutters with frequent inlets to drain the roadway.

SPU will plan the entire basin, then work with SDOT to determine which streets to improve based on technical feasibility and available funding. Not all streets will be redone at this time.

Project goals and benefits

When complete, this project will work in tandem with the flood control pump station to reduce flooding in the industrial and residential areas in the northern part of South Park. The pipe improvements will collect and convey flows to the existing drainage system and lessen overall flooding. The drainage system will direct stormwater to the flood control pump station, which will pump stormwater to the Lower Duwamish Waterway, and to the future water quality facility.