Ship Canal Water Quality Project update 11/10/22

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Ship Canal LogoCrews working at the bottom of the Fremont shaft

Earlier this month, crews connected utilities at the bottom of the Fremont shaft in preparation for the 8-foot diameter tunneling to resume from Fremont to Queen Anne.

Wait, SPU is building another tunnel?

With all the excitement around the 18-ft diameter tunnel that MudHoney is building, you may have forgotten that we’re building a shorter, smaller tunnel under the Ship Canal with an 8-ft diameter tunnel boring machine. This smaller tunnel will bring flows from our Queen Anne outfall site to our larger tunnel to be pumped to the West Point Treatment Plant.  

Our 8-ft diameter tunnel deserves some recognition too! It is unique because it follows a continuous curve, unlike MudHoney which occasionally curves around street corners to stay in the right-of-way as much as possible.

Why did SPU design a curved tunnel? That sounds complicated!

It’s a little complicated, but the savings to both project cost and community headaches are worth it. Our 8-ft diameter tunnel isn’t the only hidden infrastructure crossing under the Ship Canal. There are two other tunnels in use, one holding utility lines for SPU and one that moves wastewater for King County. Our curved tunnel connects the Queen Anne and Fremont sites while avoiding the existing tunnels. If we hadn’t gone with a slightly more complex, curved tunnel design, we would have had to build deeper shafts (sooooooo expensive) or moved the shaft sites off the public right-of-way (soooooooo much more impactful to the surrounding community).

Our 8-ft diameter tunnel swerves around the existing utility tunnels like an offensive football player avoiding oncoming defenders. Way to go, wonky little tunnel.

To learn more about the project, visit our project website. We also continue to update our Flickr albums with recent construction photos.

Gas Works Park

Show your love for Gas Works Park and our waters!

Participate in the Washington State Department of Ecology’s public comment period (ends Nov 22) and online public meeting about in-water sediment cleanup at Gas Works Park. Learn more on their website.

MudHoney graphic


MudHoney, our 18-ft diameter tunnel boring machine, has currently tunneled over 7,100 feet. This means we’ve passed the halfway point! Follow along with our tunneling tracker on our project website.

Ground monitoring is ongoing along the tunnel alignment and is done from both inside MudHoney and on the surface.


Our Ballard shaft site near Shilshole Ave NW will continue to be busy with tunneling activities until MudHoney reaches Wallingford in 2023.

During regular tunneling activities, you should anticipate:

  • Truck deliveries of concrete segments and MudHoney equipment
  • Nighttime segment deliveries and both nighttime/daytime tunnel spoils being hauled off
  • Noise and vibrations typical of a construction site

Crews are working 24 hours a day, six days a week. Sunday work may also occur. The Ballard shaft site is also the site of the future pump station.

Puget Sound Energy (PSE) has started utility relocation work on NW 56th St between 28th and 24th Avenues NW. Neighbors should have received notification directly from PSE. Please contact Eric Liaw at if you have any questions.

East Ballard

Crews continue building the mechanical and electrical (M & E) vault on NW 45th St and the diversion structure on 11th Ave NW. We recently completed pouring concrete for the M & E vault roof.

Local closures and detours:

  • 11th Ave NW, south of NW 45th St, will remain closed for the next few weeks. The contractor will open 11th Ave NW at NW 45th St to two-way traffic between Thanksgiving and New Year’s. The contractor will not be working in the intersection during this time. Traffic signals will direct traffic at the intersection of 11th Ave NW and NW 45th St.
  • NW 45th St remains closed to traffic between 11th Ave NW and 9th Ave NW; vehicles must detour onto NW 46th St
  • Burke-Gilman Trail remains detoured to the north side of NW 45th St through the project area. For safety, bicyclists should either dismount or cross train tracks at a 90-degree angle. Please use extra caution in wet weather as ramps may be slippery.

You should anticipate:

  • Heavy equipment in the area
  • Noise and vibrations typical of a construction site

Regular work hours will be Monday through Friday, from 7 am to 5 pm. Night and weekend work may occur.


We recently resumed tunneling with our 8-ft diameter tunnel beneath the Ship Canal. Noise levels from generators and fans during working hours will increase during tunneling. Crews also continue working on the diversion structure on 2nd Ave NW.

Local closures and detours:

  • On 2nd Ave NW, between Leary Way NW and NW Canal St, the street is closed to vehicle and pedestrian traffic through mid-2023. NW Canal St is open to two-way traffic to allow access during this closure.
  • NW 36th St, between Leary Way NW and 3rd Ave NW, is closed through 2023
  • Pedestrian detours are in place on Leary Way NW; please follow all detour guidance on site

You should anticipate:

  • Truck traffic on Leary Way NW as trucks bring materials and equipment to and from the site
  • Generators and fans running during work hours to power pumps and equipment, and to provide fresh air to crews
  • Crane on-site to lower pipe segments for tunneling
  • Noise and vibrations typical of a construction site

Crews are working six days a week, 7 am to 7 pm on weekdays and 9 am to 7 pm on Saturdays.


Crews continue removing the remaining contaminated soil in the southwest corner of the site.

You should anticipate:

  • Trucks coming in and out of the site
  • Noise and vibrations typical of a construction site

Regular work hours will be Monday through Friday, from 7 am to 5:30 pm.

Wallingford Conveyance Project

This week SPU executed a contract with JW Fowler to connect Wallingford’s existing combined sewer outfall pipe to the new storage tunnel. They will begin construction on this project starting on Stone Way N as early as January 2023.

Queen Anne

Crews are installing a 60-in conveyance pipe between the diversion structure and the shaft.

Local closures and detours:

  • Localized Ship Canal Trail detour at least through summer 2023 (see map). Please continue to remain alert when moving through this area.
  • West Ewing Mini Park parking closure through mid-2023

You should anticipate:

  • Trucks coming in and out of the site
  • Noise and vibrations typical of a construction site

Regular work hours will be Monday through Friday, from 7 am to 5 pm. Night and weekend work may occur.

Contact us

Please email with questions or comments or call our hotline at (206) 701-0233. You can also find information online at To support the community during active tunneling, we have changed our hotline hours to 24 hours a day, Monday through Friday.

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