Investing in the Health of the Sound and the Future of Our Region

Welcome to the Ship Canal Water Quality Project website! We’re happy you’re here.

We will continue to share updates about construction progress on this website, as they become available.

A graphic depicting MudHoney's journey tunneling from Ballard to Wallingford. Currently at 0 of 13,946ft.
MudHoney's Tunneling Update (Click or tap to enlarge)
An aerial map of the Ship Canal Water Quality Project site. The base map shows the projected storage tunnel location, which runs along Shilshole Avenue Northwest in Ballard to North 35th Street in Wallingford. Project areas are shown as purple boxes, sites include Ballard (located near the intersection of 24th Avenue Northwest and Northwest Market Street), East Ballard (located near the intersection of Northwest 45th Street and 9th Avenue Northwest), Fremont (located near the intersection of North 36th Street and 3rd Avenue Northwest), Queen Anne (located near the intersection of Queen Anne Avenue North and West Nickerson Street) and Wallingford (located near the intersection of Interlake Avenue and North 35th Street).
Project Area (Click or tap image to enlarge)

Click on the project areas to learn more

About the project

Seattle Public Utilities and King County Wastewater Treatment Division are building an underground storage tunnel to significantly reduce the amount of polluted stormwater (from rain) and sewage that flows into the Lake Washington Ship Canal, Salmon Bay, and Lake Union from our sewer system.

An aerial map of the Ship Canal Water Quality Project site. The base map shows the projected tunnel site as a dark blue line that runs from the eastern end of Fremont towards Ballard. A dotted line indicates the location of the existing pipe transfer, which runs from the end of the tunnel in Ballard to the West Point Treatment Plant, which is denoted as a black square. The areas served by the Ship Canal Water Quality project are highlighted in green and include: Crown Hill, Ballard, Fremont, Wallingford, Queen Anne, Capitol Hill and Downtown.
Map of storage tunnel alignment and the combined-sewer areas that will send flows to the new tunnel. (Click or tap image to enlarge)

Tunnel

Since the 1800s, 150 tunnels spanning over 70 miles have been constructed in Seattle for sewers, utility corridors, and transportation needs. The Ship Canal Water Quality Project includes a 2.7-mile, 18-ft and 10-in internal-diameter tunnel that will extend from Ballard to Wallingford. Tunneling operations will start in Ballard. The Ballard vertical access shaft construction started in 2020 with tunneling is planned for 2021.

Ballard

Learn more about the Ballard site

Ballard will be home to the western end of the tunnel and above-ground facilities supporting the tunnel. Tunnel boring will start at this site and move toward Fremont and Wallingford.

We started work at our site near 24th Ave NW and Shilshole Ave NW in 2018 to prepare for tunneling. This work included soil remediation, utility relocation, 24th Ave Pier replacement, and replacing a sewer outfall pipe.

Project elements in Ballard include:

  • A new 107-ft deep, 80-ft diameter shaft to hold pump station equipment and carry sewage and stormwater into the new storage tunnel
  • New pipes along NW 56th St, 28th Ave NW, and 24th Ave NW to connect the shaft to Ballard’s existing combined sewer system overflow pipe
  • A large pump station that will take the flows from the tunnel and send them to West Point for treatment
  • A new 24th Ave Pier containing art inlays by artist Christian French

After construction is completed at the Ballard site, you can expect to see:

  • Ballard Pump Station (not publicly accessible):
    • 65-ft illuminated tower with above- and below-ground mechanical equipment and odor control
    • Maintenance yard with vehicle access
    • Landscaping 
    • Fencing
  • 24th Ave NW Restoration (publicly accessible)
    • Green stormwater infrastructure
    • Pedestrian improvements 
    • Parking improvements 
    • Street-end improvements
    • Public art by artist Jeffrey Veregge

aerial map of area between 24th avenue North West and Shilshole Avenue Northwest. Tunnel barging operations are southwest of the 24th avenue pier in Salmon Bay. Dotted lines along 24th Avenue Northwest and Northwest 56th Street indicate locations for conveyance pipe alignment and microtunnel placement. A dark blue line that runs through Shilshole Avenue Northwest denotes the storage tunnel.
Construction area map (Click or tap image to enlarge)

East Ballard

Learn about the East Ballard site

Project elements in East Ballard include:

  • A new 55-ft deep, 10-ft diameter vertical shaft to carry sewage to the new storage tunnel
  • A new below-grade structure to house mechanical, electrical and odor control equipment
  • A new diversion structure, gate vault, and pipe to connect the current combined sewer system overflow pipe to the vertical shaft and storage tunnel

To learn more about the East Ballard project site, read our fact sheet.

aerial map shows area on Northwest 45th Street and is between 11th Avenue North West and 9th Avenue Northwest. Grey dotted lines along 45th Avenue Northwest and indicate the future missing link route, orange dotted lines along 45th Avenue Northwest indicate the proposed trail detour and green dotted lines indicate the Burke-Gilman Trail. The solid blue line on 11th Avenue Northwest indicates underground pipes..
Construction area map (Click or tap image to enlarge)

Fremont

Learn about the Fremont site

We anticipate construction of the tunnel to take place until early summer. During this time, there will be a large crane on-site and an uptick in deliveries for the casing pipe construction.

Additionally, in late spring, we’ll begin construction of the diversion structure in 2nd Ave NW. We anticipate 2nd Ave NW will be closed south of Leary Way NW for at least six months.

Project elements in Fremont include:

  • A new 86-ft deep, 32-ft diameter vertical shaft to carry sewage and stormwater into the new storage tunnel
  • A new diversion structure and conveyance pipe to connect the new shaft to the existing combined sewer system overflow pipe
  • A new 8-ft diameter conveyance tunnel under the Ship Canal to carry flows from Queen Anne to the storage tunnel
  • A new underground structure to house mechanical, electrical, and odor control equipment
A graphic rendering looking inside an eight-foot diameter storage tunnel. Three smaller white circles with colored borders inside the larger gray tunnel indicate different elements of the tunnel. Gray lines inside the tunnel represent temporary pipes.
Click or tap image to enlarge

Artists Preston Singletary and David Franklin collaborated on artwork for the Fremont and Queen Anne sites. This artwork is planned to be installed in late 2023.

To learn more about the Fremont project site, read our fact sheet.

aerial map of the project sitesituated between Leary Way Northwest and the Burke Gilman Trail. The dotted orange line along first avenue Northwest and Northwest 36th Street denotes the pedestrian detour. A small blue line that runs from the project area and across the Ship Canal represents the microtunnel placement.
Construction area map (Click or tap image to enlarge)

Queen Anne

Learn about the Queen Anne site

Project elements in Queen Anne include:

  • A new 74-ft deep, 20-ft diameter vertical shaft to carry sewage and stormwater into the new tunnel under the Ship Canal
  • New structures and conveyance pipe to connect the new shaft to the existing combined sewer system overflow pipe
  • A new 8-ft diameter tunnel under the Ship Canal to carry flows from Queen Anne to the storage tunnel at the Fremont site

Artists Preston Singletary and David Franklin have collaborated on artwork for the Fremont and Queen Anne sites. This artwork is planned to be installed in late 2023.

To learn more about the Queen Anne project site, read our fact sheet.

aerial map of project site situated along Third Avenue West and West Ewing Street. Green boxes within the project area indicate the following: underground pipes, cabinet, underground facility and drop shaft. A small blue line that runs from the project area and across the Ship Canal to Northwest 36th Street in Fremont represents the microtunnel placement.
Construction area map (Click or tap image to enlarge)

Wallingford

Learn about the Wallingford site

Wallingford marks the eastern end of the Ship Canal Water Quality Project and the location where tunneling will end underneath N 35th St and Interlake Ave N. Construction will take place on Stone Way N, N 35th St, and Interlake Ave N.

Project elements in Wallingford include:

  • A new 56-ft deep, 32-ft diameter vertical shaft near Stone Way N and N 35th St to convey stormwater and sewage into the tunnel
  • New pipe installation along Stone Way N and N 35th St to connect the current combined sewer system overflow pipe to the new vertical shaft
  • Removing tiebacks underneath N 35th St
  • A new small, above-ground electrical building near 3500 Interlake Ave N
  • New underground structures to house mechanical and odor control equipment
  • Site restoration and restoration of impacted roadways
  • Public art by Ryan! Feddersen

After construction at the Wallingford site is complete, SPU will retain ownership of the southern portion of the site. The site will be mostly fenced to secure utility equipment. The fenced area will house an aboveground electrical building, and a number of large, underground structures attached to the storage tunnel.

The design for the Wallingford site is complete. During design, our landscape architects reviewed the planting schemes for the North Transfer Station and the Carr Place Play Area. Their goal was to create a site that was unique to the neighborhood but still complemented the aesthetic of nearby open spaces.

Artist Ryan! Feddersen will design and install the artwork at this project site.

To learn more about the Wallingford project site, read our fact sheet.

A graphic rendering that depicts two individuals sitting on a concrete wall in front of landscaping and a black fence at the future Wallingford site.
Rendering of future Wallingford site. (click to enlarge)
A graphic rendering depicting a black electrical building at the future Wallingford site. A bicyclist is riding by the building on the road.
A rendering of the electrical building for the future Wallingford site. (click to enlarge)
An aerial landscape rendering that depicts the future Wallingford site. A black fence surrounds vegetation and buildings. The street to the left of the rendering is Interlake Avenue North and the street below the rendering is North thirty-fifth Street.
A landscape rendering plan for the future Wallingford site. (click to enlarge)
aerial map project site situated at the intersection of Interlake Avenue North and North 35th Street.  A dark grey line that runs west from the project site along N 35th Street indicates the storage tunnel.
Construction area map (Click or tap image to enlarge)