Ship Canal Water Quality Project update 6/02/22

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Ship Canal LogoMudHoney’s cutterhead tools

Some of MudHoney’s cutterhead tools that were replaced due to encountering a 10-ft boulder.

MudHoney v. Megaboulder

(This week our feature story is longer than usual. You can scroll down to see the neighborhood-specific construction updates.)

Sometimes, life can be hard. Sometimes, life throws unexpected obstacles. Sometimes, a tunnel boring machine (TBM) runs into an unfortunately large boulder. But, in those moments, what does the TBM and the capable staff who operate it do? Persevere.

A few weeks ago, MudHoney, our 18-foot diameter TBM, was tunneling eastward and ran into an enormous boulder. Although our designers and engineers had planned for a few boulders along the route, this one was exceptionally large for our area—about 10-feet tall. We have experienced tunneling engineers, contractors, and construction managers on our project, and all of them were surprised by the boulder’s size. We’re not-so-fondly calling it Megaboulder.

We paused tunneling to check on MudHoney and get more information about boulder size and strength. MudHoney passed the overall health check, but we did have to replace and repair some cutterhead tools—a difficult task to complete while under 70 feet of water pressure, and in a space only 3 feet wide inside the very front of the TBM. Our engineers, crews, and specially trained divers switched out cutterhead parts to equip it for grinding through a solid piece of rock.

We resumed tunneling—albeit at a much slower pace and with increased cutterhead inspections. Fortunately, our cutterhead modifications worked! On Friday, we successfully broke through. Tunneling has resumed at its original pace.

Long story, short: We persevered. MudHoney beat Megaboulder.

How did such a boulder get here in the first place?

Huge boulders like Megaboulder come from mountainous regions. During the last Ice Age, about 15,000 years ago, this boulder most likely tumbled down a mountain in the Cascades and hitched a ride on a glacier from the mountainous inland to the coast. As the glacier melted the boulder was dropped somewhere along modern day Shilshole Ave NW and, eventually, right in front of our MudHoney.

Let’s all cheer on MudHoney as it continues to approach East Ballard!

As a reminder, be sure to check out our Flickr albums for images from recent construction.

Ballard & MudHoney

MudHoney, our 18-ft diameter tunnel boring machine, recently resumed regular tunneling operations after grinding through a 10-ft boulder.

During regular tunneling activities, you should anticipate:

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

Crews are working 24 hours a day, six days a week and will continue until MudHoney reaches Wallingford in early 2023. Sunday work may also occur.

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

East Ballard

Crews prepared the base for the mechanical and electrical vault on NW 45th St to provide a stable surface to work on. Construction of the reinforced concrete structure will begin later this month.

You should anticipate:

  • Starting in mid-June, one-lane closure on 11th Ave NW through November 2022. Flaggers will direct northbound and southbound traffic, and directional signage will be in place.
  • Heavy equipment in the area
  • NW 45th St closed to traffic; vehicles must detour onto NW 46th St
  • Burke-Gilman Trail users remain detoured to the north side of NW 45th St
  • Flaggers will help direct traffic during daytime working hours. Please follow all detour guidance on site. 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.
  • 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.


Lane reductions on Leary Way NW, between 1st Ave NW and NW 39th St, for utility work was completed in late-May. This month, utility work will begin within the east end of the site on 2nd Ave NW. Crews also continue to work on large eight-foot conveyance tunnel pipes underneath white tents within the site from 7 am to 10 pm on weekdays, and possibly 9 am to 10 pm on weekends, over the next few months. 

During this time, you should anticipate:

  • Dust and grinding noise
  • Excavators working on-site for utility installation work
  • Truck traffic on Leary Way NW as trucks bring and remove materials to and from the site
  • NW 36th St between Leary Way NW and 3rd Ave NW closed (through the remainder of the project)
  • Pedestrian detours on Leary Way NW; please follow all detour guidance on site
  • Generators running during work hours to power equipment
  • 2nd Ave NW, between Leary Way NW and NW Canal St, closed to vehicle and pedestrian traffic for sewer and diversion structure work at least through the end of 2022
  • NW Canal St open to two-way traffic to allow access during this closure. Please do not park at the west end of NW Canal St so two-way traffic may turn around at the closure.
  • Noise and vibrations typical of a construction site

Regular work hours will be Monday through Friday, from 7 am to 5 pm. Work on the large pipes inside the tents may occur during nights and weekends as described above.


Good news, the Wallingford Conveyance project began the public bidding process late last month, taking us one step closer to bringing in contractors and completing this project. You can find more information about this project on our website and we’ll have more details about the impacts once the contractor is on board.

In the meantime, crews continue working on the Wallingford shaft walls. Another large concrete pour is expected mid-June for the upper portion of the shaft walls.

During this time, you should anticipate:

  • Concrete 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.

Queen Anne

Construction of underground vaults is ongoing through the summer. This work requires a slight adjustment to the Ship Canal Trail detour. The current Ship Canal Trail detour that has been in place for the past two years (near Ewing Park and adjacent to Seattle Pacific University) has been temporarily removed. The trail has been moved back near its original location for the summer of 2022. Our contractor will be working on both sides of the trail so please continue to remain alert when moving through this area.

During this time, you should anticipate:

  • Trucks coming in and out of the site
  • Noise and vibrations typical of a construction site
  • The West Ewing Mini Park parking lot to remain closed through mid-2023
  • A localized Ship Canal Trail detour at least through summer 2023 (see map). The trail has temporarily been adjusted for construction of the third below-grade vault through summer 2022 and will revert back to the detour shown in the linked map this fall.

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 spushipcanal.participate.onlineTo support the community during active tunneling, we have changed our hotline hours to 24 hours a day, Monday through Friday.

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