Hennepin Island tunnel


Hennepin Island tunnel

Hennepin Island tunnel was a convert|2500|ft|m|sing=on-long underground passage in Saint Anthony, Minnesota (now Minneapolis) dug beneath the Mississippi River riverbed between 1868 and 1869 to create a downstream spillway for hydro plants, milling and lumber business located upstream of St. Anthony Falls. The tunnel ran downstream from Nicollet Island, beneath Hennepin Island, and exited below St. Anthony Falls. [Parker, Dick. (October 30, 2006) Star Tribune "Retro: Saving St. Anthony Falls in 1869. Mississippi gorge almost eats Minneapolis' heart." Section news; page 3B.] [cite web |url= http://www.mpls.lib.mn.us/history/eh5.asp |title= Falls of St. Anthony |accessdate = 2007-08-02 |work= A History of Minneapolis |publisher= Minnesota Public Library] [ [http://www.mvp.usace.army.mil/history/engineering/ Engineering the Falls: The Corps Role at St. Anthony Falls] - an article on the U.S. Army Corps of Engineers website covering the history and geology of St. Anthony Falls.] [ [http://www.minneapolis-riverfront.com Minneapolis' official promotional site for the riverfront district] ]

During construction of the tunnel, on October 5, 1869, the river broke through the thin layer of limestone separating the river's bed from the tunnel. The rushing river scoured the tunnel, caving in parts of Hennepin Island and causing the earth supporting St. Anthony Falls to collapse upstream. There was serious concern that the riverbed would crumble and reduce St. Anthony Falls to a long set of rapids. However, within a few weeks, dams were built to divert the river and stop St. Anthony Falls from being washed away. The fix was temporary as the 1870 spring floods damaged some of the new dams and swept away more of Hennepin Island. By the fall of 1870, the riverbed and banks were stabilized and a wooden apron capped St. Anthony Falls to stop the upstream progression of the collapsing falls. As a direct result of the collapse of the Hennepin Island tunnel, St. Anthony Falls ultimately received a sloping concrete apron to create an artificial falls that are held out as the only major waterfall on the Mississippi River.

The site of the tunnel is about a mile upstream from the 2007 collapse of the I-35W Mississippi River bridge.

History

Hennepin Island was named after explorer, Catholic priest, and Franciscan missionary Louis Hennepin (12 May, 1626 – c. 1705). In 1865, entrepreneurs William W. Eastman and John L. Merriam had bought its sister island, Nicollet Island, with the idea of creating a tunnel from Nicollet Island under St. Anthony Falls to provide for-profit spillway services to the many milling and lumber business located upstream of St. Anthony Falls.McAuliffe, Bill. (September 29, 1997) Star Tribune "Time capsule: "The falls are going out!" Section news; page 1B.] The tunnel was to be part of a system of waterworks that supported the industries driving Minneapolis' growth. The project was designed to create more industry on Nicollet Island through the waterpower.Benidt, Bruce. (November 15, 1987) Star Tribune "River has powerful history of damage at falls." Section: news; Page 7B.]

St. Anthony Falls are made up of a hard limestone cap over soft sandstone. 10,000 years ago the falls were located near present-day Fort Snelling, Minnesota at the mouth of the glacial River Warren. However, in the succeeding millennia, the river had been washing away the sandstone and undermining the limestone lip of St. Anthony Falls, causing the falls to slowly retreat upriver near its present location.Parker, Dick. (October 30, 2006) Star Tribune "Retro: Saving St. Anthony Falls in 1869. Mississippi gorge almost eats Minneapolis' heart." Section news; page 3B.]

In 1868, workers began to dig a convert|2500|ft|m|sing=on-long tunnel beneath the riverbed from Nicollet Island downstream under Hennepin Island, exiting below the falls. For the next year, workers dug in the soft sandstone beneath the thin layer of limestone that forms the river's bed. However, by October 1869, water began seeping into the tunnel from above.

On October 5, 1869, the river broke through the thin layer of limestone separating the river's bed from the tunnel. The rushing river scoured the tunnel, caving in parts of Hennepin Island and causing the earth supporting St. Anthony Falls to collapse upstream. There was immediate, serious concern that the riverbed would crumble and reduce St. Anthony Falls to a long set of rapids. One witness remembered,

"Proprietors of stores hastened to the falls, taking their clerks with them; bakers deserted their ovens, lumbermen were ordered from the mills, barbers left their customers unshorn; mechanics dropped their tools; lawyers shut up their books or stopped pleading in the courts; physicians abandoned their offices. Through the streets, hurrying hundreds were seen on their way to the falls."

Work started immediately to plug the tunnel and hundreds of volunteers used timbers and stones. However, the river easily washed these out of the tunnel. Within a few weeks, the plug held and dams were built to divert the river and stop St. Anthony Falls from being washed away. The fix was temporary and the 1870 spring floods tore up some of the new dams and swept away more of Hennepin Island. In addition, the earth support below the Summit flour mill, Moulton's planing mill and a wheat storehouse were undermined and each of these was tipped into the river.

By the fall of 1870, the riverbed and banks were stabilized and a wooden apron capped St. Anthony Falls to stop the upstream progression of the collapsing falls. The apron buried the falls' jagged rocks and large waterfall cataract and tamed the falls' tumbling water.

Aftermath

The tremendous damage caused by the Hennepin Island tunnel brought lawsuits and demands for political change. A central issue at that time was whether local taxpayers should pay for repairs that would enrich riverfront industrialists. The tunnel collapse was one of the factors leading to the merger of St. Anthony with Minneapolis in 1872.Fact|date=August 2007 To the relief of the local population, the United States Army Corps of Engineers made the repairs using federal money on the pretext that it was protecting navigation. Seven years after the tunnel collapse, by 1876, the falls were stabilized with an underground dike and low dams that largely are still in place upstream of Stone Arch Bridge. By 1880, the Army Corps of Engineers had covered the face with a sloping concrete apron, creating the artificial falls. The federal government spent $615,000 on this effort, while the two cities (St. Anthony and Minneapolis) spent $334,500.cite book|title=Mill City: A Visual History of the Minneapolis Mill District|last=Pennefeather|first=Shannon M.|date=2003|publisher=Minnesota Historical Society|location=St. Paul, Minnesota]

ee also

*Hennepin Avenue Bridge
*Hennepin Avenue
*Hennepin Island Hydroelectric Plant
*History of Minneapolis, Minnesota
*Louis Hennepin
*Mill Ruins Park
*Mills District, Minneapolis
*North Star Woolen Mill
*Northwestern Consolidated Milling Company
*Pillsbury "A" Mill
*Washburn "A" Mill
*I-35W Mississippi River bridge

References

----
* Kane, Lucile M. (1966). "The waterfall that built a city: The Falls of St. Anthony in Minneapolis." Publisher: Minnesota Historical Society. ASIN B0007DN9Z8


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Hennepin-Island-Tunnel — Einsturz des Hennepin Island Tunnel 1869 bei den Saint Anthony Fällen. Der Hennepin Island Tunnel war ein 2500 Fuß (etwa 760 m) langer Tunnel in Saint Anthony (heute Teil von Minneapolis), der zwischen 1868 und 1869 unter dem Flussbett des… …   Deutsch Wikipedia

  • Hennepin — ist der Name von Louis Hennepin (* 1626; † um 1705), belgischer Franziskaner, Missionar und Entdecker Orte in den Vereinigten Staaten: Hennepin (Illinois) Hennepin (Oklahoma) Hennepin County, Verwaltungseinheit in Minnesota Sonstiges: Hennepin… …   Deutsch Wikipedia

  • County roads in Hennepin County, Minnesota — Hennepin County, Minnesota, United States maintains a number of county routes, many of them county state aid highways (CSAH). This includes a number of streets through the city of Minneapolis. Contents 1 CR 1–CR 25 2 CR 26–CR 50 3 CR 51–CR 75 …   Wikipedia

  • Saint-Anthony-Fälle — Luftaufnahme der St. Anthony Fälle in Minneapolis, Minnesota …   Deutsch Wikipedia

  • Saint Anthony Falls — Infobox nrhp | name =St. Anthony Falls Historic District nrhp type =hd caption =Aerial view of Saint Anthony Falls with the upper dam; there is also a lower dam. location= Minneapolis, MN area = built =Apron built 1848 architect= Apron by Ard… …   Wikipedia

  • List of tunnels in the United States — The following is a list of tunnels in the United States of America.See: List of tunnelsAlabama*Bankhead Tunnel, US 98, Mobile *George Wallace Tunnel, Interstate 10, Mobile *5th Avenue North Tunnel, Birmingham The tunnel runs beneath the site of… …   Wikipedia

  • Interstate-35W-Mississippi-River-Brücke — 44.978888888889 93.245 Koordinaten: 44° 58′ 44″ N, 93° 14′ 42″ W w1f1 …   Deutsch Wikipedia

  • Saint Anthony Falls — Luftaufnahme der St. Anthony Fälle in Minneapolis, Minnesota. Die Saint Anthony Fälle (englisch Falls of Saint Anthony) befinden sich in der Nähe des Stadtzentrums von Minneapolis im US Bundesstaat Minnesota. Sie waren bis zum Bau eines Wehrs aus …   Deutsch Wikipedia

  • Liste der Contributing Properties im Saint Anthony Falls Historic District — Saint Anthony Fälle Die Liste der Contributing Properties im Saint Anthony Falls Historic District nennt die 85 historischen Objekte, die zu diesem geschützten Gebiet in Minneapolis, Minnesota, gehören. Von dieser Liste sind 56 Objekte noch… …   Deutsch Wikipedia

  • List of contributing properties in the St. Anthony Falls Historic District — The following are the 85 contributing properties in the Saint Anthony Falls Historic District in Minneapolis, Minnesota, United States. About 56 still exist. The district s archaeological record is considered to be one of the most endangered… …   Wikipedia