April 2023 Minneapolis Central City Tunnel Project Update

Via an April 21 e-announcement from the City of Minneapolis:

Project Overview

The City of Minneapolis Public Works Department is constructing a new parallel storm tunnel, enlarging a portion of the existing storm tunnel, and constructing a new tunnel access in Downtown Minneapolis.

The new tunnel is being constructed parallel to the existing tunnel located under Washington Ave S between Nicollet Mall and Chicago Ave. The existing tunnel under Chicago Ave between Washington Ave S and the Mississippi River is being expanded to handle the increased stormwater capacity. The purpose of this project is to reduce pressure in the existing tunnel, provide more room for future growth, and to reduce the need for future repairs and tunnel failures.

Project Map

Latest Project News

Mississippi River Portal

• Crews have completed excavation of the existing storm tunnel at the Mississippi River for the season and will resume later this fall when they can access the storm flow again. Until then, crews will continue to work on lining the tunnel with concrete and will be on site through May.

2nd Ave

• Crews have completed mining the new parallel storm tunnel under Washington Ave from the new tunnel access shaft in the southbound lanes of 2nd Ave S, just north of the Washington Ave intersection for the season. Crews will continue to work on lining the tunnel with concrete through the summer.

Portland Ave

• Crews have completed mining the new parallel storm tunnel under Washington Ave from the existing tunnel access shaft at the northeast corner of the Washington Ave and Portland Ave intersection for the season. Crews will continue to work on lining the tunnel with concrete through the summer.

Tunneling Progress

In April, the project reached 97% completion with excavation. Crews have removed approximately 67,800 tons of material to date. As noted in the infographic above, this is equal to the weight of 6.7 Eiffel Towers. The final excavation will occur next winter.

Lining progress

In April, crews continued to work on the concrete tunnel lining. To date, 2,150 cubic yards of concrete have been poured. As noted in the infographic above, this is about 65% of the volume of an Olympic swimming pool. This process is approximately 13.5% complete.

Long-term closures/restrictions

The north westbound lane, bike lane, and parking lane remains closed on Washington Ave between Portland Ave and Park Ave. These closures will remain in place until the project is completed.

• During this closure, pedestrians can still use the sidewalks along Washington Ave.
• Crosswalks across Washington Ave and Portland Ave will remain open.
• Bicyclists will share the traffic lane.
• The existing left turn lane on Washington Ave at the Portland Ave intersection will temporarily become a left turn and through lane.

The north sidewalk along Washington Ave remains restricted between Hennepin Ave and Nicollet Mall.

• During these restrictions, pedestrians share the bike lane on Washington Ave.
• The crosswalks at the Washington Ave intersections of Nicollet Mall and Hennepin Ave remains open.

The sidewalk on the east side of 4th Ave S remains restricted through the end of the project. The dewatering well and pumps are installed in this area.

• Pedestrians can use the sidewalk on the west side of 4th Ave S.
• The crosswalk at the Washington Ave and 4th Ave intersection remains open.
• Access to driveways off 4th Ave S remains open.

The west sidewalk of Portland Ave south of Washington Ave will remain restricted to pedestrians around the dewatering well and pumps until the project is completed.

The parking lot and trail near Mill Runs Park will open May 1.

• During May, the trail will have flaggers to allow concrete trucks to pull into and out of the work site.

2nd Ave S remains a single lane in each direction using the northbound lanes between Washington Ave and 1st St S. Access will be restricted until the project is completed.

• Access to driveways off 2nd Ave S remain open. There may be short-term access delays while crews move equipment and materials around.

NEW: Project timing update:

When is the project going to be done?

• The anticipated project completion date is June of 2024.

I thought that you were supposed to be done this year?

• When initially awarded the contract for the Central City Parallel Tunnel (CCPT) project, the anticipated completion was summer of 2023. Due to multiple construction obstacles the project schedule has been adjusted to a later date.

What were some of the obstacles?

• While performing work in the storm tunnel outlet located in the Mill Ruins Park near the Stone Arch bridge, crews uncovered historically significant underground structures.
• Crews had to excavate more soil and debris material from over the tunnel than initially anticipated, some of which was contaminated.
• Because work in portions of the tunnel is in an active stormwater flow, some work can only occur during a five-month window of time due to safety issues.

A note from the project team

We know that a later completion date will not be great news for many residents, businesses, or visitors that live and work in the areas of aboveground work sites, but we wanted to convey this information to you in order to set a realistic expectation for the revised project timeline. We also realize that the noise and activity associated with construction projects is an inconvenience and undesirable to those residents and businesses who are in close proximity to the job sites. It is the goal of Public Works to minimize our construction timeline and disturbance to the public. The CCPT project is crucial to the City, as it services most of our downtown area. The new storm tunnel will be able to convey stormwater much more effectively from the downtown district to the river during high-intensity rain events.

The project has worked to address all concerns and issues brought to our attention to date, and we will continue to do so moving forward.  As always, you can communicate with us via the project website and communications number with any concerns or issues you might have. Thank you for your patience and understanding.

Stay Connected

There are multiple ways to get information including email updates and ongoing stakeholder meetings. Visit the project website for more information and to sign up for project updates: https://www.minneapolismn.gov/government/projects/central-city-tunnel/

Email the project team: info@mplscentralcitytunnel.com

Contact the project hotline: 612-888-9418