Ship Canal Water Quality Project update 2/9/2023

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Wallingford Conveyance Detour Update:

Our contractor has mobilized into the north half of the intersection of N 34th St and Stone Way N. This means that westbound N 34th St is temporarily closed to through traffic between Wallingford Ave N and Woodland Park Ave N. Our contractor will maintain local access to Densmore Ave N, Woodlawn Ave N, Woodland Park Ave N, and private driveways, including access to the North Transfer Station on N 34th St. Westbound traffic on N Pacific St should turn right onto Wallingford Ave N to access the signed detour. The westbound traffic on N Northlake Way should turn right onto Densmore Ave N, then right on N 34th Street to access the detour via Wallingford Ave N and N 40th St. Please adhere to the Road Closed Ahead signage and follow the detour route signs.

Expect increased travel times through the area. We apologize for the inconvenience this detour may cause, and we will follow up with more information on getting around during construction.

Our 8-foot diameter conveyance tunnel made it to Queen Anne!

A diver being lowered into the Queen Anne shaft

A diver was lowered into the Queen Anne shaft, which was temporarily filled with water before receiving the 8-ft diameter conveyance tunnel boring machine.

Back in November, we dove deep into the unique design and need for an 8-foot diameter curved conveyance tunnel that connects the Queen Anne sewer outfall site to the larger 18-foot diameter storage tunnel that MudHoney is digging between Ballard and Wallingford.

Last week, we hit another huge project milestone when we completed said conveyance tunnel between Queen Anne and Fremont. On Groundhog Day, our 8-foot diameter tunnel boring machine (TBM) arrived at the outer wall of the Queen Anne shaft near Seattle Pacific University. Our TBM operators had successfully driven toward and broken through a predetermined circular target in the wall of the shaft with an extremely high level of precision, down to the millimeter.

If you were in the neighborhood, you might have wondered if you could look into the Queen Anne shaft to see our smaller tunnel boring machine, but you would have just seen the pool pictured above. This 75-foot-deep pool was only entered by our expert divers, who were tasked with descending into the abyss to tighten the seals around the TBM face shield when it came through the inner shaft wall. The seal prevented groundwater and slurry surrounding the machine from entering the shaft as it got pushed onto a cradle. Depending on your personality, this may sound like the coolest or the most terrifying job in the world.

Why would we make our TBM exit underwater? Our engineers need to maintain the pressure balance at the TBM face to prevent ground settlement, and one way to do that is to fill the tunnel endpoint (shaft) with water to match the groundwater pressure at that location. Our crews have since drained the water and have hoisted the tunneling machine out from the shaft. Next, they’ll begin removing the temporary support pipes used to power the TBM and will work on installing the three permanent pipes that go inside this new 8-foot diameter conveyance tunnel.

To learn more about the project and to see more detailed detour information, visit our project website. We also continue to update our Flickr albums with construction photos. 



Our 18-ft diameter TBM has tunneled over 9,714 feet! MudHoney has resumed tunneling after a planned pause in Fremont and is on its journey toward Wallingford. 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 this year.

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.

Puget Sound Energy (PSE) has utility relocation work planned along NW 56th St in February. Please contact Eric Liaw at if you have any questions.

East Ballard

Crews continue building the mechanical and electrical vault on NW 45th St and the diversion structure on 11th Ave NW, including the reinforced concrete floor and walls.

Local closures and detours:

  • The contractor has returned to a one-lane traffic configuration on 11th Ave NW at NW 45th St. Traffic signals and flaggers will direct traffic at the intersection during single lane closures.
  • 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.


Our 8-ft diameter conveyance tunnel made it to Queen Anne! You may see tunneling equipment being removed from the site. Crews are also backfilling around and working inside 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 remains 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
  • Periodic closures of the southern eastbound lanes will be necessary to complete some utility work in the southern area of Leary Way NW at 2nd Ave NW

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 working in the shaft

Regular work hours will be Monday through Friday, from 7 am to 6 pm; and some Saturdays from 9 am to 6 pm.


Crews installed shoring piles and are preparing for construction of the electrical building.

On February 6, Wallingford Conveyance project crews mobilized onto Stone Way N, between N 34th St and N 35th St, for conveyance pipe installation and other utility work. We have reached out to nearby neighbors and businesses and will continue to share more details about this work.

Local closures and detours:

  • Stone Way N, between N 34th St and N 35th St, is closed to vehicle traffic. Sidewalks remain open and a two-way bike lane on the east side of Stone Way N will be created soon.

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.

Queen Anne

Our 8-ft diameter conveyance TBM has made it to Queen Anne! Crews will be pulling tunneling equipment out of the Queen Anne shaft and will start installing piping and an air duct inside the 8-ft diameter conveyance tunnel casing.

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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