I am very accustomed to being in and around rivers, growing up in many of the small towns along the Mississippi River, the 4th longest river in the world. I can even remember as a child, hearing a little jingle to remember how to spell it. I have seen it used as transportation for goods via barges, for recreation with boats and jet skis, and even for sport from fishing. But I never stopped and thought about how truly mighty and beneficial the Mississippi is. The Mississippi starts in Minnesota and snakes its way south all the way through the United States before finally emptying into the Gulf of Mexico. It has many tributaries including the Missouri River, the Ohio River, and the Arkansas River and its watershed contains nearly 40% of the landmass of the United States (Wikipedia, 2020).
As with most every river, the Mississippi has seen numerous changes over its lifetime. The current course is dated back to roughly the year 1000 AD. But there has been quite a few notable deviations. In 1826 the Mississippi suddenly changed its course and cut off part of Tipton County, Tennessee and essentially attached it to Arkansas. The state boundaries were were based on the river, but since the Mississippi is mainly an alluvial channel and this change was so sudden, both states recognize still recognize the old channel boarder. Alluvial channels form in loose sediment that was previously brought there from the river, so the channel can frequently meander or braid (Tarback, 2016). There was another incident where a town, Kaskaskia, Ill., which was settled on a peninsula in the Mississippi eventually lost most of its residents and a majority of the land due to erosion (Wikipedia, 2020).
As you would expect, the Mississippi carries all sizes of load down the river, from the microscopic soil, sand and clay particles that give it the muddy brown color its most known for to large rocks. But the most interesting aspect of this is that this actually causes the mouth of the river to change roughly every few hundred years, and could easily do that if current levees are damaged due to flooding, which is very common along the Mississippi (web.mit, 2010). I can recall a few "once in a lifetime" floods, that I have witnessed in my 31 years living here. There are precautions in place to prevent flooding in the form of levees along the entire river. The idea behind levees is that they can control the flow of the river and how quickly it empties downstream. This isn't always fool proof as sometimes the water gets too high and goes up and around the levees. While the levees help help with flooding issues, they are contributing to another concerning issue. With the placement of frequent levees and dams, the Mississippi isn't discharging as much sediment as is needed to sustain the Mississippi River Delta, and it's actually shrinking. This is caused by sediment and other essential land building materials being caught on levees and dams and not making its journey all the way to the gulf (MississippiRiverDelta.org, 2020). This also poses another problem. As I stated before, the Mississippi is a series of alluvial channels, and as sediment builds up, the floodplain grows. When the floodplain grows it increases flood risk for more people and makes the river vulnerable to creating another route downstream (MississippiRiverDelta.org, 2020).
Tarback, F. L. (2016). Essentials of Geology. New Jersey: Pearson Education.
Coastal Land Loss in the Mississippi River Delta. (2017, July 20). Retrieved November 08, 2020, from https://mississippiriverdelta.org/our-coastal-crisis/land-loss/
Mississippi River - General. (2010). Retrieved November 08, 2020, from http://web.mit.edu/12.000/www/m2010/finalwebsite/background/mississippiriver/mississippi-general.html
Mississippi River. (2020, October 27). Retrieved November 08, 2020, from https://en.wikipedia.org/wiki/Mississippi_River
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