Battery Street Tunnel and North Surface Streets

Project news (last updated March 31, 2021)

  • This Saturday, April 3, Denny Way will be fully closed between 6th Avenue and Dexter Avenue from 8 a.m. to 5 p.m. This closure will allow crews to paint new lane striping around the intersection of Denny Way and Seventh Avenue North. Signs and police officers will help direct vehicles around the closure. Inclement weather could delay this closure to the following Saturday, April 10.
  • The left turns movements from Seventh Avenue North to John Street and Denny Way are now open.
  • Crews are completing sidewalk and lighting work on Battery Street, and beginning final punchlist work. People traveling in the area should expect single-lane closures and sidewalk detours.
  • Learn more about the projects in our Flickr photo collection and our YouTube channel.

Project overview

When the Alaskan Way Viaduct closed, SR 99 no longer ran through the Battery Street Tunnel. As part of the Alaskan Way Viaduct Replacement Program, the Battery Street Tunnel is being decommissioned and filled. Filling and sealing the tunnel also provides an opportunity to rebuild and reconnect three streets in South Lake Union – Thomas, John and Harrison – previously cut off by SR 99.

Needs & benefits

Like the viaduct, the Battery Street Tunnel was built in the 1950s and was seismically vulnerable. Any new or continued use of the tunnel would have required prohibitively expensive renovations. Crushed concrete produced from the viaduct’s demolition was used to fill much of the Battery Street Tunnel, which kept the material out of a landfill. The rest of the tunnel will be filled with several types of concrete.

The old northern approach to the Battery Street Tunnel is being rebuilt as Seventh Avenue North, an arterial with wider sidewalks, two travel lanes in each direction, transit lanes to help buses get to and from SR 99, and new signalized intersections at John and Thomas streets.

Design and construction

Construction activities began in early February 2019. Work on Seventh Avenue North and Battery Street are scheduled to be complete in spring 2021.

The major Battery Street Tunnel work elements include:

  • Decommissioning and removing the tunnel’s utility and mechanical systems.
  • Removing hazardous materials from the tunnel.
  • Filling the tunnel and sealing its entrances.
  • Installing and upgrading utilities beneath Battery Street.
  • Street restoration along Battery Street, including sidewalk improvements, new curb ramps, street lighting and other pedestrian improvements.

The major North Surface Streets work elements include:

  • Filling in the trench approaching the old Battery Street Tunnel and bringing the street up to match the surrounding grade.
  • Rebuilding Seventh Avenue North (formerly Aurora Avenue North) between Denny Way and Harrison Street as a local street with dedicated transit lanes.
  • Reconnecting Thomas and John streets, compatible with future green street improvements on Thomas Street.
  • Electrical duct bank, gas line and water line work.
  • Paving, sidewalks, striping and landscaping.

What to expect

During construction, neighbors and travelers should expect:

  • Traffic lane closures along Battery Street, Borealis Avenue, and Seventh Avenue North. In addition to occasional temporary closures of cross streets and alleys.
  • Temporary detours for people walking, biking and driving.
  • Construction equipment staged at the south end of the Battery Street Tunnel.
  • Tunnel fans in operation while crews are working inside the tunnel.
  • Temporary building and parking access restrictions according to previously negotiated Temporary Construction Easements.
  • Increased truck activity on Battery Street and near the north and south portals.
  • Vibration from tunnel filling activities, plus other typical construction effects such as increased dust and noise.
  • Most construction during the daytime, with occasional night work.

Timeline

  • February 2019: Battery Street Tunnel closes to all traffic.
  • May 2019: Crews begin filling lower half of the Battery Street Tunnel with crushed concrete from the viaduct.
  • June 2019: Traffic on Seventh Avenue North moves to inside lanes.
  • December 2019: Bus lanes open on Seventh Avenue North.
  • July 2020: Crews begin filling the remainder of the Battery Street Tunnel with low-density cellular concrete.
  • October 2020: Tunnel filling is complete and crews begin filling the south portal of the Battery Street Tunnel.
  • Early 2021: Crews complete most work on the North Surface Streets Project.
  • Spring 2021*: Crews complete final restoration work on the surface of Battery Street.

*Based on the contractor’s current timeline and subject to change.

Funding

Work on the Battery Street Tunnel and North Surface Streets is part of the Alaskan Way Viaduct Replacement Program. The contract that included this work, as well as the demolition of the viaduct and funds associated with rebuilding Alaskan Way along Seattle’s waterfront, was $366.2 million. Funding comes from state, federal and local sources.

Contact

Call the 24/7 program hotline at 1-888-AWV-LINE (298-5463) or send an email to viaduct@wsdot.wa.gov.

Street grid map of Seattle highlighting Battery Street in orange

Tunnel partially filled with gray rubble and a construction vehicle's headlights at the far end