Mississipi River

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The Mississipi River System is a series of rivers draining much of the United States.[1] It is the largest river system in North America. Its current mouth is south of the important port city of New Orleans, Louisiana. The headwaters of the Missouri River, the largest tributary, are in the foothills of the Rocky Mountains. The headwaters of the main branch are in Wisconsin, near Lake Superior. The headwaters of the Ohio River, Kentucky River and Tennesee River are in the foothills of the Appalachian Mountains. The mouth of the Mississipi was once near New Madrid, Missouri, and the land south from there, to the current mouth in Louisiana, on the Gulf of Mexico, are formed from silt, carried from upstream.

Much of the river system was navigable, and it remains an important method for transporting bulk cargo.[2][3] Unlike some other rivers, like the Yangtze, bulk cargo intended for cities on the upper river is transferred to large barges, that are towed by special purpose towboats, because the river is too shallow for ocean going vesselse to sail far inland..

The United States Corps of Engineers is responsible for keeping the river navigable.[3] Its goal is to maintain a navigable channel at least nine feet deep and 300 feet wide. It maintains several dozen canal locks on the upper river, which make it possible to push barges all the way to and from Minneapolis, Wisconsin, except when a drought results in a drop in water levels. The Corps of Engineers maintains levies, to try to prevent flooding of the areas adjacent to the rivers. They maintain underwater wing dams, that help keep the navigable channel in a constant position.

Prior to the work of the Corps of Engineers the navigable channels within the river were constantly changing, as hazards to navigation, like sandbars were deposited, or eroded.[1] On the lower river, where the river meanders in huge curves, a flood could result in a brand new channel being left on what had been dry land, and in cutting off curves into oxbow lakes. Riverports could end being cut off from the river due to flooding cutting of the curve they were on.

References

  1. 1.0 1.1 Jonathon Raban (1981, 1998). [books.google.ca/books?id=SuRdVgJR9F8C&printsec=frontcover&dq=jonathan+raban+old+glory&hl=en&sa=X&ei=I2XjULCRLoXbrAGtlIDwDg&redir_esc=y Old Glory: A Voyage Down the Mississippi]. Random House. ISBN 9780375701009. books.google.ca/books?id=SuRdVgJR9F8C&printsec=frontcover&dq=jonathan+raban+old+glory&hl=en&sa=X&ei=I2XjULCRLoXbrAGtlIDwDg&redir_esc=y. 
  2. Ryan Haggerty (2012-12-26). "Barge traffic piles up as water levels fall on Mississippi: Drought has slowed river traffic in southern Illinois". Chicago Tribune. Archived from the original on 2013-01-01. http://www.webcitation.org/query?url=http%3A%2F%2Farticles.chicagotribune.com%2F2012-12-26%2Fnews%2Fct-met-mississippi-river-water-level-20121226_1_barge-companies-water-levels-river-traffic&date=2013-01-01. Retrieved 2013-01-01. "The drought that devastated crops throughout the Midwest this summer has made the mighty Mississippi dangerously narrow and shallow, threatening to choke off a vital transportation artery that carries billions of dollars of raw materials and commodities through the heart of the country." 
  3. 3.0 3.1 Ken Lieser Lee (2012-12-21). "Low water on Mississippi causes barge companies to lighten loads". Missouri Farmer Today. Archived from the original on 2013-01-01. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.webcitation.org%2Fquery%3Furl%3Dhttp%253A%252F%252Farticles.chicagotribune.com%252F2012-12-26%252Fnews%252Fct-met-mississippi-river-water-level-20121226_1_barge-companies-water-levels-river-traffic%26date%3D2013-01-01&date=2013-01-01. "The so-called “dustpan” dredge is part of the corps’ ongoing efforts to maintain a channel that is at least 9 feet deep and 300 feet wide. It sucks sand and sediment out of the channel and through a pipeline to the side."