Project Update - October 7, 2019. See Project Updates below.
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Metropolitan Council Environmental Services (MCES), operator of the metro-area wastewater collection and treatment system, will be constructing two deep tunnel access shafts and making repairs to the existing sewer tunnel beneath 4th Street in downtown Minneapolis.
The sewer tunnel was originally constructed in 1885 and is more than 80 feet deep. A void space above the tunnel was left after it was constructed. The space has been deteriorating, allowing sandstone pieces to potentially fall and damage the sewer tunnel. To make improvements, construction crews will install two new access shafts beneath 4th Street, remove debris in the void, repair damage to the sewer tunnel, and then fill the void with grout.
The access shafts will be located just east of Hennepin Avenue and Marquette Avenue, on the south side of 4th Street. Three lanes of eastbound traffic will remain open throughout the majority of the work, but they will be shifted to the north side of the road.
The overall process will be time-consuming due to the depth of the tunnel and limitations of working in a confined space. Construction is anticipated to begin January 7, 2019 and be completed by spring 2020.
4th Street Tunnel Repair Project Overvew (PDF)
4th Street Tunnel Repair Project Area Map (PDF)
Illustration of Tunnel Access Shafts (PDF)