Tunnel boring begins in Ballard for Ship Canal Water Quality project

Meghan Walker Ballard

Ballard’s tunnel boring machine—MudHoney—has begun its tunneling journey to Wallingford.

MudHoney is digging an 18-foot-wide, 2.7-mile-long wastewater storage tunnel between Ballard and Wallingford as part of the Ship Canal Water Quality project. Another tunnel boring machine will be digging an 8-foot-wide tunnel between Fremont and Queen Anne to connect Queen Anne’s wastewater basin to the larger tunnel being dug by MudHoney.

Seattle Public Utilities has created a map to help folks follow MudHoney along its journey; they’ll update it on the project website as it digs away. (They’ve even created some coloring sheets for kiddos.)

MudHoney will tunnel up to 50 feet per day and will take scheduled maintenance breaks that could be several weeks long. SPU says that during tunneling, you should expect the following:

  • More heavy equipment, such as cranes, to arrive on site, potentially at night.
  • Truck deliveries of paving material, concrete, and equipment for MudHoney and tunnel activities. Some of these deliveries may take place overnight.
  • Noise and vibrations typical of a construction site.

Tunneling crews will be working 24 hours a day, 5 days per week, and will continue until MudHoney reaches Wallingford in the fall of 2022. SPU says ground monitoring is ongoing along the tunnel path from both inside MudHoney and on the surface.

At the East Ballard site near Fred Meyer, crews are preparing the site for the excavation of the diversion structure while also preparing to install a temporary main bypass on NW 45th St. SPU says to expect the following:

  • 11th Ave NW reduced to single lane traffic until late November. The area just south of the intersection of 11th Ave NW and NW 45th St will be controlled by flaggers during the day and traffic lights at night (see map). This will allow crews to excavate and work in the roadway.
  • The final connections for the water main bypass will require a short, temporary water outage. If your service will be impacted, you’ll receive a door hanger with more information.
  • Heavy equipment in the area to install dewatering wells and excavation support piles, followed by excavation and concrete work for the outfall interception and diversion structures in 11th Ave NW, and the mechanical and electrical vault in NW 45th St.
  • 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. 
  • Noise and vibrations typical of a construction site.

Crews will be working regular work hours; Monday through Friday, from 7 a.m. to 5 p.m. with occasional night and weekend work. For anticipated traffic impacts through the rest of 2021, visit the project website.

The 8-ft conveyance tunnel boring machine in Fremont began tunneling towards Queen Anne last week. SPU says utility work in Leary Way NW and on-site will continue, along with the following:

  • Dump trucks and excavators working on site and an increase in truck traffic on Leary Way NW as trucks haul away excavated material and bring materials to the site.
  • NW 36th St between Leary Way NW and 3rd Ave NW closed (through remainder of the project).
  • Pedestrians detoured to the north side of Leary Way NW.
  • Generator running during work hours to power the TBM and associated equipment.
  • Generators running intermittently to power the dewatering pumps.
  • 2nd Ave NW, between Leary Way NW and NW Canal St, closed to vehicle and pedestrian traffic for sewer and diversion structure work through the end of the year.
  • NW Canal St is open to two-way traffic to allow access during this closure. Please do not park at the west end of NW Canal St to allow two-way traffic to turn around at the closure.
  • Noise and vibrations typical of a construction site.

There have been crews intermittently working along Leary Way NW on a new water main, which will cause occasional lane closures on Leary Way NW and temporary water outages. If your residence or business wil be impacted, SPU will drop off a door hanger card with more info.