Pump Station and Water Quality Facility
This project is a first step toward protecting people from flooding and protecting the Duwamish Waterway from polluted stormwater runoff.
The northeastern 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. This causes water to back up in the drainage system and sometimes flow back out of inlets and catch basins, flooding the neighborhood.
- Not all streets in the area have a drainage collection system. Additional connections cannot be built until the pump station is installed so that the pipes can drain at high tide.
- 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 collection system in the street to connect to.
The pump station will make it possible to pump stormwater from the existing drainage system during high tide when the outfall to the Lower Duwamish Waterway is underwater.
Water Quality Facility
From the pump station, stormwater will be sent through the facility where it will be filtered to remove a variety of pollutants that are common in urban runoff. The stormwater will be released through the existing outfall to the waterway. This will result in cleaner water and a healthier environment.
The site for this project was selected because of its location on the main stormwater drainage pipe where it empties into the waterway. The facility will be located along the edge of 7th Avenue South near Riverside Drive and on adjacent land parcels already owned by Seattle Public Utilities.
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 run remotely so staff will only visit the site periodically to check and maintain it.
How much will it cost / how is it funded?
The project is estimated to cost $ 19.5 million. A grant from the King County Flood Control District funds about $ 4.5 million. Drainage rates fund the remaining $15 million.
Construction schedule / what’s next?
Construction is estimated to begin in spring 2014 and is expected to last about 24 months.
To ask questions or let us know what you think, email the project manager or give him a call: Jim Johnson, (206) 684-5829.