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 2

Construction activities at the Seward Park site:
The construction crew is continuing with concrete work to build the buried storage tank. A large pour is scheduled to take place on Thursday, May 5, to place a sump area, floor slab and tank wall. Large concrete pours are weather-dependent.

During the pour day, there will 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. On non-pour days, the crews will work within normal hours.

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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