| SUBTERRANEAN VENICE Copyright (c) By Greg Brick |
| In 1857 the Minneapolis Mill Company began construction of the First Street Canal along the Mississippi River in the nascent city of Minneapolis. This system was created based on the model of Lowell, Massachusetts. Its purpose was to provide waterpower to flouring mills, sawmills, etc. Water was diverted from the river above St. Anthony Falls into the First Street Canal, which served as a headrace canal, dropped down through shafts, spinning the turbines, and exited to the river again below the falls by way of tailrace tunnels carved in soild bedrock. The headrace canal, which was just below the street decking, has been filled in, but the abandoned tailrace tunnels, which are lined with limestone rubble masonry, are extensive. Some are flooded to a depth of 8 feet with murky, sewage-tainted water, and require a boat to navigate. Over time they have been gradually silting in, owing to sediments brought in by sewers. The system is organized around two main trunk passages that run parallel to the river: the First Street Tunnel (not Canal) and "City Tunnel." The latter was constructed for a former city water works, whose intakes have since migrated upriver beyond the polluted area, first to Camden in 1904, and later to their present location in Columbia Heights. It is characterized by square brick pillars and a glutinous red mud. The First Street Tunnel, however, is like a branching tree. Each branch is named for an individual mill above that point on the surface, and when you follow them they terminate at iron draft tubes and deflection cones where the water came down. The Crown Mill is a particularly impressive example. Another example is the Old Standard Tunnel, which for many years served as an (unintended) relief valve for the sanitary sewer system of Minneapolis. I was once inadvertently caught in the mill tunnels during a one inch per hour rainfall, and recalled seeing a veritable flood of raw sewage erupt from a hole in the wall. The water level in the whole system rose more than a foot before I had exited. The upstream end of the First Street Tunnel is good boating country. Until the early 1990s, there used to be a large wood-plank-&-steel-drum raft tethered there (constructed by persons unknown) and you could pole your way along for hundreds of feet, one person serving as the gondolier. Then during one trip I noticed that it had been beached on a mudbank, badly damaged. In the late 1990s, seeing that it had refloated itself somehow, though scarely seaworthy anymore, I had the temerity to attempt using it again. The damned thing broke right in half, leaving me to swim fully clothed back to the nearest mudbank. There are some fairly extensive erosional voids or caves in the sandstone at the upstream end. The largest is the City waterworks cave, with its huge red brick piers to hold up the ceiling. It is accessed from the First Street Tunnel, not City Tunnel. Rafting around back there, you can also float off into the Arctic Mill spur, which connects the First Street Tunnel with City Tunnel. Most of the tunnels do connect at some point, although the actual aperture may be small and obscure. The oldest part of the system is the Cataract-Holly Mill tunnel, a yellow brick confection dating back to 1859. This was the way we used to enter before the construction of Mill Ruins park began in 2000. Before that, you would come down through a steel trap door at the foundation ruins of the King Midas Mill, and descend a 40-foot spiral stirway that had been installed by the Corps of Engineers during their Upper Harbor project in the late 1950s. At that time I had my own padlock on the trapdoor, priding myself on having the keys to the Minneapolis underworld in my pocket! For a more detailed description of the mill tunnels, see the article in Minnesota Archeologist. |