Seattle Public Utilities Mami Hara, General Manager/CEO

South Park Drainage Improvements


Current South Park Conveyance study area; boundaries may change based on technical feasibility.

What & Why

Seattle Public Utilities is currently working on three stormwater projects to reduce flooding in the lower industrial basin located in the northwestern part of South Park and improve water quality in the Lower Duwamish Waterway.

This project will complete preliminary design for a new stormwater collection system in roadways that don’t currently have one. Scope and budget will ultimately determine which roads SPU can construct new drainage systems for. Selected roadways will be rebuilt to ensure they drain into the new inlets and catch basins.

We are planning to construct the flood control pump station first to overcome the effects of high tide. We are also planning to build a water quality facility that will treat stormwater from the storm drain system before it flows into the Duwamish Waterway.

This project is supported in part with funding from the King County Flood Control District.

What’s happening now?

The South Park drainage improvement project is a joint effort with SDOT. The project is currently in the options analysis phase for design of the drainage system. The SPU team is working with a team of technical consultants to determine the best approach and sequencing for the planned improvements. In early 2017, outreach to the industrial area of South Park and directly impacted businesses/residents will gather feedback on the proposed plan and use this feedback to inform the options analysis and design phases.

SPU will analyze and plan drainage improvements for the entire project area. However, the 2016 – 2021 budget is not sufficient to complete all the work. The plan will include all the work, along with a phased approach for full implementation. The initial phase of construction will be based on available budget. The scope and schedule of the first phase will be determined as a part of the plan.

Project goals and benefits

When complete, this project will work in tandem with the flood control pump station and water quality facility 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 drainage system and lessen flooding in the right-of-way and on private properties. The conveyance system will also direct stormwater to the flood control pump station, which will pump stormwater to the Lower Duwamish Waterway, and to the future water quality facility.

Project documents

Meetings & Events

No meetings scheduled at this time.


Jason Sharpley, project manager
(206) 615-0030

Sheila Harrison, line of business representative
(206) 684-5899

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