South Park Water Quality Facility
This project will improve water quality in the northern part of South Park.
Project description
Improving chronic flooding and drainage issues in South Park
SPU will build a water quality facility to treat stormwater from the drainage system before it flows into the Duwamish Waterway. Before we can operate the new water quality facility, we must construct a pump station that will ultimately send flows to the water quality facility.
What's happening now?
SPU is currently selecting water quality treatment technology, project site, and creating initial facility layout, sizing and operation plan.
Community benefits
When complete, this project will clean stormwater before it flows into the Duwamish Waterway. Combined with the pump station, this project will allow the system to accommodate the expansion of the drainage improvements being planned in South Park.
Community engagement
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2020-2024
- Options evaluation, property acquisition
2025-2029
- Design and construction
Seattle Public Utilities is currently working on three stormwater projects in northwest South Park’s lower industrial basin to reduce flooding and improve water quality in the Lower Duwamish Waterway.
- A drainage and roadway project to construct streets and a drainage system to improve chronic flooding and drainage issues.
- A flood control pump station to overcome the flooding effects of high tide.
SPU originally decided to build a stormwater treatment facility in the 7th Ave S drainage basin because of the industrial nature of the lower (and northern) portion of the basin, and because the system drains into the Duwamish Waterway, which has poor water quality. Large-scale, centralized treatment of municipal stormwater is a new and emerging approach to addressing polluted stormwater runoff. At that time, SPU selected a treatment technology based on what was available and created a design for the combined water quality facility and pump station.
As more data became available about the performance and maintenance requirements of the treatment technology selected, SPU decided to take another look at other available and more effective treatment technologies. SPU is currently selecting a treatment technology for the water quality facility.
From the pump station, stormwater will be sent through the water quality facility, where it will be treated to remove a variety of pollutants that are common in urban stormwater runoff. The treated stormwater will then be released through the existing outfall to the Duwamish Waterway, resulting in cleaner water and a healthier Duwamish Waterway.