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.
Currently, the Seattle Public Utilities is planning to continue with construction in your area. We are working closely with our Public Health – Seattle & King County partners, our construction management teams, and private contractors to ensure that everyone supporting this project is cautious and safe. If there are changes to the construction schedule or planned work, we will notify you once public information is available.
The City of Seattle and King County are taking steps to protect the health of our community by making recommendations that are meant to slow the spread of novel coronavirus and reduce the number of people infected. Please learn more about COVID-19 at www.kingcounty.gov/covid. Thank you.
We will continue to share updates about construction progress on this website, as they become available.
Pieces of the Tunnel Boring Machine have started to arrive in Ballard
It's here! Our tunnel boring machine arrived from Germany and is making its way to Ballard from the Port of Tacoma. Because the machine is so big, it is arriving in pieces via several oversized deliveries and will be assembled at our Ballard site over the next few months. The photos below show crews unloading a section of the lower shield last week, and then what the machine will look like fully constructed.


Construction progress in 2020
Construction is underway at all five project sites. As of December 2020, the secant pile wall in Queen Anne is complete, Fremont’s is nearing completion, and we are breaking ground on this activity in Wallingford. Soil stabilization in East Ballard continues, and we just reached a huge project milestone in Ballard - completing the concrete pour for the 14-ft thick, 87-ft wide shaft floor. We are thankful for your patience and support as we continue this essential work to reduce combined sewer overflows in our waterways by 2025.
Visit our Flickr page to see photos of recent construction activities.

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.
In some parts of Seattle, sewage and stormwater (rain) share a set of pipes; this is called a combined sewer. During heavy rains (What? Rain? Here?) the water often exceeds the pipes’ capacity (known as an overflow to us sewer nerds), sending untreated sewage (yep, that means poop) and stormwater into the Ship Canal. These overflows can harm fish, wildlife, and the environment, and can contain pollution.
In 2018, 84% of the city’s overflows came from the combined sewers in Crown Hill, Ballard, Fremont, Wallingford, Queen Anne, Downtown, and Capitol Hill. During a heavy storm, the new tunnel will capture and temporarily store more than 29 million gallons of untreated stormwater and sewage until the treatment plant is ready for it. The tunnel will improve water quality regionally by keeping more than 75 million gallons of polluted stormwater (from rain) and sewage on average each year from flowing into the Lake Washington Ship Canal, Salmon Bay, and Lake Union.



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 will begin construction in 2020 and tunneling is planned to begin in 2021.
The purpose of the tunnel is to collect and hold stormwater and sewage flows which would normally overflow into the Ship Canal. Along the tunnel path, five vertical shafts will be built (in Ballard, East Ballard, Fremont, Queen Anne, and Wallingford). They will collect stormwater and sewage flows from each basin and send them approximately 40 – 80 ft below ground into the new storage tunnel. In order to bring flows from Queen Anne into the storage tunnel, SPU will build an 8-ft diameter tunnel underneath the Ship Canal connecting the vertical shafts in Queen Anne and Fremont. For the final piece of the SCWQP, SPU will install new pipes to connect the existing sewer systems to the new drop shafts.

While no significant ground movement is anticipated, as a precaution, crews will be monitoring over 200 structures along the tunnel path before, during, and after tunnel construction. To learn more about ground monitoring, read our fact sheet.
Ballard
Construction in Ballard is underway
In January and February 2021, crews will continue installation of the permanent walls of the 122-ft deep vertical shaft. Additionally, during this timeframe, our tunnel boring machine will be making its way to Seattle from Germany. We anticipate the parts to arrive and be ready for assembly in Ballard in early 2021.
You should anticipate several concrete trucks and other deliveries coming through the site and an uptick in oversized-vehicles on Shilshole Ave NW.
In March, crews will construct temporary equipment in the shaft to prepare for tunneling. Tunneling is expected to begin in the summer of 2021.

- Crews will generally work from 7 a.m. to 5 p.m., Monday through Friday, though occasional night and weekend work is expected to accommodate large concrete pours and deliveries
- Large equipment, like cranes, being staged on site
- Short interruptions on Shilshole Ave NW for trucks entering the work zone, and 24th Ave NW for trucks exiting the site; please pay attention to flaggers
- Parking restrictions along the east side of 24th Ave NW so construction trucks can exit the work site
- 24th Ave NW Pier may have intermittent closures throughout construction
- Noise typical of a large construction site
- Access to all buildings and businesses will be maintained
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 upcoming tunneling. This work includes soil remediation, utility relocation, 24th Ave Pier replacement, and replacing a sewer outfall pipe.
Project elements in Ballard include:
- A new 100-ft deep, 90-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 contains 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
About the Ballard Pump Station concept: Our designers have been inspired both by our underground infrastructure and the Ballard community. The cylindrical shape mirrors the pump station and below-ground equipment space. The frame around the building echoes the industrial feel and scaffolding of Ballard's shipyards. Near the tower will be smaller buildings for equipment as well as parking for our amazing maintenance crews.
Artist Jeffrey Veregge is working to create public art for the pump station.
To learn more about the Ballard project site, read our fact sheet.

Ballard Conveyance
Once the new storage tunnel is built, crews will install a 2,000-ft long, 60-in diameter pipeline in Ballard along 24th Ave NW, NW 56th St, and 28th Ave NW to convey polluted stormwater and sewage from the Ballard neighborhood into the storage tunnel.
When this work starts in 2023, you can expect single-lane and full-street closures, intersection closures, and parking restrictions on impacted blocks. We will provide more updates and information about these impacts as we get closer to the start of this work.
East Ballard
Construction in East Ballard is underway
In January and February 2021, crews will continue soil stabilization and ground improvement work in NW 45th St and 11th Ave NW. These activities help prepare the site for upcoming excavation and underground construction work, like tunneling. You should anticipate noise and vibrations from drill rigs and pumps on site. During this time, one lane of 11th Ave NW will be closed for construction just south of NW 45th St. Two-way traffic on 11th Ave NW will be maintained, and traffic will be controlled by flaggers during working hours and traffic signals at night.
In March, the contractor will install shoring for the mechanical vault installation in NW 45th St. There will be an uptick in traffic to the site as dump trucks haul away excavated material.

- Work hours will be from 7 a.m. to 5 p.m., Monday through Friday
- Possible weekend and nightwork to maintain progress
- The Burke-Gilman Trail will be detoured to the north side of NW 45th St beginning as early as April 2020
- Traffic impacts to 11th Ave NW and NW 45th St, including one-lane and full-road closures, will occur intermittently now through 2022. Please refer to and scroll through the East Ballard phasing diagram below to see what traffic impacts you should anticipate during a specific time period. Schedule is subject to change.
Dec. 2020 – March 2021*
Soil stabilization work
Approximate work zone
Burke-Gilman Trail detour
- NW 45th St closed to traffic; vehicles must detour onto NW 46th St.
- 11th Ave NW allows two-way traffic via one lane controlled by flaggers during work hours and an electronic signal overnight.
- Trail users detoured to the north side of NW 45th St; flaggers to help direct traffic during work hours.
*There will be no road closures on 11th Ave NW Thanksgiving through New Years. Schedule is approximate and subject to change.
March 2021 – June 2021*
Shoring installation, diversion structure excavation
Approximate work zone
Burke-Gilman Trail detour
- NW 45th St closed to westbound traffic; westbound vehicles must detour onto NW 46th St.
- NW 45th St allows eastbound traffic to travel in westbound lane.
- 11thAve NW allows two-way traffic via one lane controlled by flaggers during work hours and an electronic signal overnight.
- Trail users detoured to the north side of NW 45th St; flaggers to help direct traffic during work hours.
*Schedule is approximate and subject to change.
June 2021 – Dec. 2021*
Diversion structure, vault and drop shaft installation
Approximate work zone
Burke-Gilman Trail detour
- NW 45th St closed to traffic; vehicles must detour onto NW 46th St.
- 11thAve NW allows two-way traffic via one lane controlled by flaggers during work hours and an electronic signal overnight. Note, 11th Ave NW expected to fully open to traffic in July 2021.
- Trail users detoured to the north side of NW 45th St; flaggers to help direct traffic during work hours.
*There will be no road closures on 11thAve Thanksgiving through New Years. Schedule is approximate and subject to change.
Project elements in East Ballard include:
- A new 60-ft deep, 10-ft diameter vertical shaft to carry sewage to the new storage tunnel
- New pipe installation along NW 45th St to connect the current combined sewer system overflow pipe to the new vertical shaft and storage tunnel
- A new below-grade structure to house mechanical and electrical equipment and odor control
To learn more about the East Ballard project site, read our fact sheet.
Fremont
Construction in Fremont is underway
Between January and March 2021, crews will excavate the interior of the vertical shaft and install utilities on site and in Leary Way. During this time, you should anticipate dump trucks, excavators, and vactor trucks working on site and an uptick in traffic in Leary Way NW as trucks haul away excavated material. The utility work will also require lane closures in Leary Way NW.
In early spring, we’ll start preparing the shaft to launch our smaller tunnel boring machine underneath the Ship Canal to build an 8-ft diameter tunnel to the Queen Anne site. The tunnel will be 646-ft long and will house an air duct and two conveyance pipes. See graphic below to learn more about the tunnel.
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.

- Crews will generally work between 7 a.m. and 5 p.m., Monday through Friday
- Possible weekend and nightwork to maintain progress.
- Full closure of NW 36th St between Leary Way NW and 3rd Ave NW
- Closure of 2nd Ave NW between Leary Way NW and Canal St
- Temporary roadway detours on streets adjacent to the project area. Leary Way NW will remain open to traffic, but several lanes will be temporarily closed for construction
- Pedestrian sidewalk detour on north side of Leary Way NW
- Increased truck traffic
- Parking restrictions near work zone
- Removal of some trees in the project area
- Burke-Gilman Trail to remain open except temporary impact during conduit installation (likely one week)

Project elements in Fremont include:
- A new 85-ft deep, 32-ft diameter vertical shaft to carry sewage and stormwater into the new storage tunnel
- New pipe installation 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
- A new underground structure to house mechanical and electrical equipment and odor control
Artists Preston Singletary and David Franklin are collaborating on artwork for the Fremont and Queen Anne sites.
To learn more about the Fremont project site, read our fact sheet.
Queen Anne
Construction in Queen Anne is underway
In January, crews will excavate the interior of the vertical shaft. During this time, you should anticipate dump trucks and excavators working on site and an uptick in eastbound traffic on Nickerson St as trucks haul away excavated material.
In February, crews will pour the shaft’s concrete floor, which will require several concrete and rebar deliveries. In early spring, crews will prepare the site to receive the 8-ft tunnel boring machine from Fremont (not anticipated to arrive until late summer/early fall).

- Construction-related noise, traffic, dust and vibrations
- Increased truck traffic along W Nickerson St and 3rd Ave W
- Parking restrictions and roadway detours
- Ship Canal Trail detour from August 2020 through summer 2022
- Closure of West Ewing Mini Park and associated parking lot
Project elements in Queen Anne include:
- A new 75-ft deep, 20-ft diameter vertical shaft to carry sewage and stormwater into the new tunnel under the Ship Canal
- New pipe installation 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
Artists Preston Singletary and David Franklin are collaborating on artwork for the Fremont and Queen Anne sites.
To learn more about the Queen Anne project site, read our fact sheet.
Wallingford
Construction in Wallingford is underway
In January 2021, we’ll start secant pile wall construction. In an effort to be as transparent as possible, we want to let you know it will involve several months of intense, loud construction with long work days at the project’s Wallingford site.
During secant pile construction you can expect:
- Heavy equipment on site such as the drill rig, an oscillator, and a crane. Trucks coming in and out of the site to haul away excavated material and deliver concrete.
- Noise from the drill rig. This rig is loud and work will start as early as 7 a.m as allowed by City of Seattle code. We start early in the morning to allow the contractor to complete more of the work during daylight hours to improve safety, to maximize the use of expensive, heavy machinery each day and, to complete work as efficiently and cost-effectively as possible.
- Vibration from the drill rig. You may be able to feel the vibration in your home or business. This is expected. We are monitoring vibration levels on site to ensure they are within allowable levels.
- Normal work hours are from 7a.m to 5p.m, Monday through Friday, although work may extend into the early evening, on occasion to complete the concreting of a pile. It’s possible the contractor may also work on Saturdays as needed.
We anticipate secant pile wall construction to last through March. Once the secant pile wall is complete, we’ll begin excavating the vertical shaft. This work will be relatively quieter, but you should anticipate excavators working on site and an uptick in traffic as dump trucks haul off soils.

- Construction-related noise, traffic, dust, and vibrations
- Staging of equipment and construction vehicles at the project site located at 3500 Interlake Avenue N
- Sidewalk closure of the east side of Interlake Ave N
- Parking restrictions and roadway detours
- Northound lane impacts on Interlake Ave N with flaggers present to direct traffic
- Single lane closures on N 35th St and Stone Way N for tieback removal and pipe installation
- Removal of some trees in the project area
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 60-ft deep, 30-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 maintenance and odor control building near 3500 Interlake Ave N
- New underground structures to house mechanical and electrical equipment, and odor control
- Restoration of impacted roadways
Artist Ryan! Feddersen is working to design an art installation at the project site.
To learn more about the Wallingford project site, read our fact sheet.

Wallingford Conveyance
Once the new storage tunnel is built, crews will install a 213-ft long, 36-in diameter pipeline along Stone Way and a 412-ft long, 42-in diameter pipeline along N 35th St to convey polluted stormwater and sewage from the Wallingford neighborhood into the storage tunnel.
When this work starts in late 2022, you can expect lane closures, traffic and bus route detours 31, 32 and 62, and parking restrictions on N 35th St and Stone Way N, with several months of work in the intersection of Stone Way N and N 34th St. We will provide more updates and information about these impacts as we get closer to the start of this work.