Minneapolis Underground

Minneapolis Underground. . , The City Waterworks , Even during the heyday of the milling period, the towering mills, rail lines, bridges, and other aboveground features were only part of the setting which made the district an industrial powerhouse. Hidden underground was a complex system of tunnels, draft tubes, wheel pits, and raceways which conveyed water between the river and the many users of the waterpower of St. Anthony Falls. While many of the district's surface features have been completedly [sic] or partially demolished, much of this underground network remains, unseen and unused, but still a valuable historic resource., Almost all the mills and other facilities driven by this waterpower system were privately owned. Unique in this context was the tiny City of Minneapolis waterworks and pumping station, located adjacent to the headrace (intake canal) just above the Falls. Minneapolis established a municipal water system in 1867, just twelve years after its incorporation as a city. In 1871, it bought the first Bassett Sawmill, a two-story stone building constructed in 1866, and installed rotary waterpowered pumps to convey river water throughout the newly-laid city water mains. The city had to buy access to this water from the Minneapolis Mill Company, which had claimed rights to the river water in 1856. In 1886, a brick structure was added to the upstream side of the building to house a steam power plant which supplemented the waterpowered pumps. This facility operated until 1904, when the waterworks still in use today were opened on the east bank of the river in Columbia Heights. The buildings were then used for storage until torn down around 1930., The water that powered the facility's rotary pumps was returned to the river through the "City Tunnel," exiting first into the tailrace (or outflow) canal via the opening to your left. This tunnel, like the others in the system, exploited the area's unusual geology in its construction. The tunnel shaft was dug through the soft St. Peter sandstone, with the bottom of the solid Platteville limestone layer immediately above serving as its roof. The sandstone walls were armored with brick and limestone blocks, and several layers of wood planking were laid on the sandstone floor for protection from scour. Brick columns spaced at twenty-foot intervals along the center of the tunnel helped support the limestone overhead. These readily-available resources (locally-quarried limestone, brick, and wood) are the most common building materials found throughout the milling district., This inspection survey from the 1950s shows a portion of the tunnel system shortly before its final abandonment, including the City Tunnel (in blue). The footprint of the City Waterworks is shown in brown., Reuse and Restoration , When the tailrace canal was excavated and rewatered as part of the development of Mill Ruins Park in 2001, the City Tunnel was once again used to convey water between the river and the tailrace. At first, this water flowed along the floor of the tunnel as in the historic period. However, the wood planking of the floor surface had grown soft and fragile over time and was prone to damage from the water flow. In 2005, a sealed pipe system was installed within the tunnnel [sic] to contain the water flow and ensure that the historic resource of the tunnel would remain intact. Scoured areas at the bases of the old roof support columns were also repaired., These photographs show elements of the tunnel interior, including the plank flooring, brick walls and columns, draft tubes, and limestone ceiling, prior to restoration in 2005, The City Tunnel, along with the other components of the area's waterpower system, is a contributing feature in the St. Anthony Falls Historic District, listed on the National Register of Historic Places. Therefore, all aspects of this project were required to comply with the Secretary of the Interior's Standards for the Treatment of Historic Properties, as implemented through review by the Minnesota State Historic Preservation Office and the National Park Service. Through careful design, the legacy of our past can both be preserved and made accessible and vital., 2004 aerial view of Mill Ruins Park and vicinity overlaid with locations of City Tunnel and City Waterworks, The City Waterworks: Historical Views , 1873 , 1874 , 1879 , 1885 , 1885 , 1891 , 1912, Preservation of the historic City Tunnel at Mill Ruins Park is being supported in part by a Save America's Treasures grant administered by the National Park Service, Department of the Interior. Additional funding is provided by the Metropolitan Parks and Open Space Commission and the Minneapolis Park and Recreation Board.