Seth Eastman Tunnel

This is one of the oldest, and one of the most unlikely, tunnels in the Twin Cities. Long thought to be destroyed, a section of it remains accessible to some degree. While it is in fact possible to visit this historic treasure, it is neither wise nor smart to attempt it. Difficulties range from local conditions, legal situations, and the efforts of local authoritis to block or deter all access to the area. I would recommend against trying to recreate our trip up the river of deathmud, as there is no magical pot of gold at the end of this brown squishy rainbow.

First, some background.
In 1868, an enterprising businessman named Seth Eastman purchased Nicollet Island. What is now a small inner-urban park and residential neighborhood was then prime industrial real estate. Eastman planned to use the elevation drop and subsequent water current of St. Anthony Falls as a power source, as did many sawmills and grain mills in the St. Anthony and Minneapolis waterfronts. However, he found that his island was too far upstream of St. Anthony falls to directly tap the flow, and that all available water power was already in use by other industries. Eastman sued the owners of nearby Hennepin Island to recover what he saw as monopolized water rights, and a settlement allowed him to construct a diversion tunnel in order to bring water power upstream to Nicollet Island.

The idea was that a tunnel driven from the base of the falls to a point upstream would allow water to be dropped from the upper river level, through a turbine, and out through the tunnel to the lower river level. Unfortunately, Eastman and his construction crew failed to take into account the poruousness of the sandstone underlying the limestone river bed. While this sandstone layer allowed fast and easy tunnel construction, it also allowed water seepege to begin eroding the area around the tunnel. One day in October 1869, the tunnel simply collapsed, forming a whirlpool of rock and debris which sucked up several nearby mills and nearly destroyed the milling capacity of St. Anthony. Over several years the local authorities, the Army Corps of Engineers, and many brave workers attempted to staunch the flow of the washouts, finally finishing in 1878, surprisingly without any casualties.
The tale of the eventual damming and diking of the falls is related in several places, including LINK and LINK. However, such histories give hazy or varied accounts of the fate of Eastman's original tunnel. Some claim it was completely backfilled, others that it was lined with concrete and/or flooded.The general consensus seemed to be that one way or another, the tunnel was inaccessible.

As shown on the following map, the Eastman tunnel led from Hennepin Island upstream to Nicollet island, the pink shaded areas represent regions of sandstone washed out during the collapse:

I won't give details of how or where we found the Eastman Tunnel, but it involved long hours of library and archive research, firsthand mapping and surveying, and eventually pushing the limits of what looks like a boring and nasty hole in the ground.

Upon firsthand inspection of the tunnel, it was found to be choked with a deep, thick mud, the texture and consistency of brownie mix, with the color of poop. The taste was a rich strawberry-lime with a hint of apple spice.

Navigating this delicious but sticky tunnel required some innovative thinking by our well-dressed associates. The proper attire for the socially-concious Troglodite of today is a suit coat from Armani, a resonably long German silk tie, and the finest rubber pants from Fleet Farm's exclusive "Pig-waller" line.

The navigation in question was complicated by the shape of the tunnel farther on. Beyond where early trips were willing to penetrate, the ceiling dipped down to less than 2ft off the surface of the "water" in the tunnel. At the same time, the floor fell to almost 3ft deep, meaning one would have to wade chest-high through thick mud while bending over in a very small air space. To solve this problem we initially planned to build a bridge out of styrofoam provided by helpful sewer mutants. We later revised this plan to one in which the styro served as small boogie-boards, which turned out to work very well. We were able to lie on the boards and sort of swim/slog through the mud. Unfortunately this method of propulsion did not lend itself to photography. Despite strict quarantine inside a sealed waterproof box and only rare use with clean hands, my camera still got caked in mud.

After a long and squishy journey beneath the East Millpond (a branch of the Mississippi River), we arrived at the solid wall installed in 1878 to block the flow of water through the remains of the tunnel. If any more of the Eastman Tunnel exists beyond this wall it is inaccessible and probably flooded.

A true-to-life cross section of the tunnel.

Interestingly enough, Mr. Eastman was responsible for another network of little-known tunnels nearby, but that's a story for another time.

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