Seattle Public Utilities Ray Hoffman, Director

North Henderson

  • North Henderson Project Site Aerial photo of North Henderson Combined Sewer Overflow Reduction project site in April 2016.
  • North Henderson Basin North Henderson project area.

What & Why?

What's happening now?

Construction will be underway on the Seward Park site between early 2015 and mid 2017. The park remains open, but parking will be affected. View parking map (pdf).

May 20

Construction activities at the Seward Park site:
On Saturday, May 21, the construction crew will be on site from 9 a.m. to 5:30 p.m. to stay on schedule. The noise impacts will be similar to a regular work day and include hammering and sawing related to shoring installation for the tank top deck.

During the next few weeks, the crew is scheduled to work four, 10-hour weekdays instead of the regular five. The crew will not be working Friday, May 27, or Monday, May 30, and these longer days will help the crew stay on schedule. The work hours will be 7 a.m. to 5:30 p.m. The contractor will not work over Memorial Day weekend.

The next large concrete pour is scheduled to take place on Friday, June 3. Large concrete pours are weather-dependent. During the pour day, there will be a high volume of concrete trucks going to and from the site. For the safety of park visitors, and to ensure work is completed as efficiently as possible, the south parking lot will be closed. Truck deliveries will last from approximately 7 a.m. to 5 p.m. but crews may remain on site until 10 p.m. to complete finishing work. Finishing work is performed by hand and is relatively quiet.

Project goals and benefits

This project will reduce the frequency of sewage overflows into Lake Washington to no more than one per year per outfall (on average). SPU plans to complete two new underground storage facilities in North Henderson to store excess combined sewage and stormwater during major rain. The underground storage facilities are in the following locations:


Ask Us

Alan Lord, PE, Project Manager
(206) 233-1565

Please specify the project site with your comments:

  • Seward Park (Basin 44) or
  • 57th Ave. S. right-of-way (Basin 45)

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