Portage Bay 138 Gate Retrofit & Pump Station 20 Improvement Project

What & Why

Portage Bay 138 is a combined sewer basin, where combined sewage and stormwater flows to Pump Station 20 at the street end of E Shelby St and is pumped to a treatment plant.

During heavy rain events, high volumes of stormwater can overwhelm the sewer system causing a combined sewage overflow (CSO) into Portage Bay. The combined mixture of raw sewage and polluted stormwater can be harmful to humans, aquatic life, and other wildlife.

For this project, Seattle Public Utilities (SPU) will be modernizing the way our existing infrastructure manages high flows during rainstorms. To accomplish this, SPU will remove the existing flow restriction device attached to the buried storage tanks beneath the northern sidewalk on E Shelby St, and replace it with an automated gate. This will allow SPU to optimally manage flows in the storage tanks in real time.

SPU is also making improvements to Pump Station 20, which is also located at the street end of E Shelby St, to help us continue to provide reliable sewer services to the community.

Because of the proximity of the work on Pump Station 20 to the Portage Bay Gate Retrofit project and the above-ground impacts, SPU will perform this work at the same time. This will help reduce the duration of construction in the area and other construction impacts on the community as well as minimize restoration costs.

What's happening now?

The project is currently in the design phase and scheduled to go into construction in mid-2020. 

On Thursday, July 18, the project team held a drop-in event at the project site. Thank you to everyone that came by. If you couldn’t make it, we want to make sure you are up to date on the project. Here us some updated information regarding construction impacts:

Q: How will emergency vehicles reach residents through the construction zone?

We have worked with the Seattle Fire Department for them to develop an emergency services plan for our construction. Emergency services will be able to reach residents during construction.

Q: How will trash be picked up during construction?

During construction, you will be able to bring your trash/compost/recycling to the same location as you normally do. Our contractor will ensure that cans are moved to a location where the truck is able to pick them up.

Q: How will mail be delivered during construction?

Pedestrian access will be maintained at all times during construction and will allow for mail delivery.

Q: How will residents be notified about upcoming work?

There are multiple ways the project team will keep in touch with the community. We will be out in the neighborhood continuing to engage residents in-person prior to construction. We will also send project notifications and share updates via the project listserv and project website.

As we move get closer to the beginning of construction, we will continue to engage the community and answer any questions or concerns about construction impacts. In the meantime, please review the Fact Sheet and FAQs for more information.

Project goals and benefits

The Portage Bay 138 Gate Retrofit & Pump Station 20 Improvement Project will improve water quality and public health by reducing the number of CSOs into Portage Bay. This work will reduce the risk of pump station failure and maintain safe working conditions for SPU crews within the pump station, in addition to helping SPU comply with industry standards and regulations.

Project documents