Storage Shafts Beside I-35W Traffic, Minneapolis Skyline Beyond
Interstate 35W stormwater storage tunnel construction site with circular concrete sections and active traffic above.
The I-35W Stormwater Storage Facility in Minneapolis consists of large underground shafts built to hold excess runoff during heavy rain and snowmelt, easing pressure on the city's combined sewer system. MnDOT undertook the project alongside broader work on the freeway corridor connecting downtown Minneapolis to the southern suburbs. The shafts are excavated as deep circular chambers lined with reinforced concrete before being capped and buried beneath the highway shoulder. Once complete, the system routes stormwater away from immediate discharge into the Mississippi River, reducing the frequency of overflow events during storms.
Photo taken in February 2022.
