Lower Mississippi River

“The people of the Delta fear God and the Mississippi River.” So begins “The Mississippi River,” a chapter in David Cohn’s memoir, Where I Was Born and Raised (1948). After describing how the people increasingly turned to God as the river approached flood, he writes, “For God and the river are immortal and immemorial. Like life, the river gave birth to this land; like death it comes to reclaim what it has given. Then the hand of man is impotent and refuge is in God alone.” William Alexander Percy echoed this theme: “With us, when you speak of ‘the river,’ though there be many, you mean always the same one, the great river, the shifting, unappeasable god of the country, feared and loved, the Mississippi.”

Both authors refer to the Lower Mississippi River, which historically forms the western border of Mississippi. (Because of changes in the channel by nature and the Army Corps of Engineers since creation of the state, some parts of Mississippi are now on the western side of the river, while some parts of Arkansas and Louisiana are on the eastern side.) By the time the river leaves Mississippi and enters Louisiana, it has collected water from thirty-one states and two Canadian provinces, a drainage basin stretching from New York to Montana and encompassing more than 1.2 million square miles. Major tributaries include the Missouri, Ohio (largest by volume), Tennessee, Arkansas, and Yazoo River systems. The Atchafalaya is the only distributary stream, draining water out of the Mississippi through the Sidney A. Murray Jr. Hydroelectric Station and Old River Control Structure south of Natchez. Consequently, the greatest volume in the entire Mississippi River drainage basin flows along Mississippi’s western border. At flood stage, almost twice as much water flows past Rosedale, Greenville, Vicksburg, and Natchez as passes New Orleans or exits the mouth of the river.

The Lower Mississippi begins at an elevation of 270.5 feet above sea level at the confluence of the Mississippi and the Ohio Rivers at Cairo, Illinois. It proceeds to the sea over a natural course of 954 river miles (although the straight-line distance is only 600 miles), giving it an average slope of only six inches per mile. From just north of Vicksburg to its mouth, the bed of the river lies below sea level. Ranking fifth among the world’s rivers in average discharge, the Lower Mississippi is very turbulent and powerful. Historically it meandered through the Mississippi Alluvial Valley in a sinuous pattern, with each meander cutting into the bank on the convex edge and depositing sediments on the concave edge. As meanders become more extreme, the point of land inside the meander becomes connected to its neighboring bank by a narrow neck, which can be cut off during floods. This natural process allows the river to shorten its route to the sea and leaves behind oxbow lakes, which eventually fill in with sediment. Prior to human intervention, this process occurred more or less continuously over several thousand years, with the river channel or the channels of tributary streams moving across the floodplain and leaving behind oxbows and new land as older land was eroded.

The floodplain of the river is filled with alluvium that is several hundred feet deep in some places. This waterborne sediment is fine-grained and composed primarily of sand, silt, and clay. In the northwestern part of the state, all or parts of nineteen counties lie within the alluvial plain called the Mississippi Delta, but the floodplain itself continues along the river south of the Delta until it exits into Louisiana. This plain was created by the river, which historically enriched it by regular flooding that deposited new alluvium incrementally and sometimes destroyed the land as the river reclaimed its sedimentary burden. In such alluvial systems, the highest ground is adjacent to the channel because floodwaters lose momentum, drop their sediment load, and build natural levees when they overflow the channel proper. This high ground is both convenient to river travel and safer in time of flood; hence it was settled before the rest of the floodplain. It is also sandier because sand settles more quickly from the water than does silt, and sandier soils are preferred for cotton culture. Finer-grained particles such as clay precipitate farther from the river channel, creating back swamps with heavier “gumbo” soils.

In the absence of human intervention, the river naturally flooded on a regular basis, and the floodplain, including all of the Delta, was a swampy bottomland hardwood forest interspersed with canebrakes, cypress stands, and oxbow lakes. Early European and African settlers encountered huge trees and forests filled with panthers, red wolves, black bears, deer, alligators, and diverse smaller creatures, including the ivory-billed woodpecker. Clearing the forests, either by logging or creating deadenings (girdling of trees), was usually the first order of business. Permanent use of the cleared land for agriculture required construction of levees walling off the river, but once done, the only obstacle to large-scale agriculture was the tree stumps. The arrival of railroads beginning in the 1870s allowed immigrants easier access to the land and carried lumber and commodities to shipping points.

Flooding on the Lower Mississippi River became more problematic after human settlement increased in the Delta region, with major flood events in 1782, 1828, 1858, and as recently as 1993 and 2011; lesser floods in 1844, 1850, 1851; and troublesome floods in 1862, 1865, 1867, 1882, 1883, 1884, 1890, 1897, 1903, 1912, 1913, and 1922. During the Great Flood of 1927 the river carried a volume of 2.5 million cubic feet per second and reached a width of sixty miles below Memphis. The levees crevassed (broke) near Scott, Mississippi, and forty-one other locations in Arkansas, Louisiana, and Mississippi, eventually flooding twenty-seven thousand square miles (nearly 16.6 million acres) and displacing more than seven hundred thousand people in the Lower Mississippi Valley. This flood caused direct economic losses estimated between $3.3 and $12.6 billion (in 2016 dollars) and was so catastrophic that prior to Hurricanes Katrina and Rita it was considered the greatest natural disaster in US history. Levee construction had previously been the responsibility either of individual landowners or of local levee boards, but after the US Congress passed the Flood Control Act of 1928, the US Army Corps of Engineers bore responsibility for levee construction to prevent flooding and promote economic development.

In late April and early May 2011, as a result of a fourteen-day rainfall and northern snowmelt, the Delta experienced flooding from the Mississippi River and her major tributaries of a magnitude unseen since 1927. The Mississippi reached flood stage in Greenville (48 feet) on 28 April, eventually cresting at 62.22 feet on 16 May. The Delta south to Natchez remained at flood stage until the first and second weeks of June. Major highways, including portions of US Highway 61, were cut off by floodwaters, and more than 350 residences from Greenville to Natchez were destroyed. More than 1,400 homes suffered damage, and more than 2,600 residences, businesses, and other structures ultimately were affected by the flood. Damage in Mississippi was estimated to exceed one billion dollars.

The river created the land of the Delta, provided it with fertile, rock-free soil, and predisposed it to large-scale agriculture, especially the growing of cotton. Until the second half of the twentieth century, cotton culture required large numbers of field hands and mules. Today, walled off by massive levees from view and mind, the Lower Mississippi River is primarily a conduit for shipping and conveying floodwaters. Much of the batture land (the land on the river side of the levee) is owned by timber companies and leased to hunting clubs. Army Corps of Engineers wetland regulations protect some forested wetlands, and the land’s potential to support new natural-resource-based economic development ventures is being explored.

Further Reading

  • Stephen Ambrose and Douglas Brinkley, The Mississippi and the Making of a Nation (2002)
  • John M. Barry, Rising Tide: The Great Mississippi Flood of 1927 and How It Changed America (1998)
  • David L. Cohn, Where I Was Born and Raised (1948)
  • Pete Daniel, Deep’n as It Come: The 1927 Mississippi River Flood (1997)
  • Anuradha Mathurand and Dilip da Cunha, Mississippi Floods (2001)
  • Mikko Saikku, This Delta, This Land: An Environmental History of the Yazoo-Mississippi Floodplain (2005)

Citation Information

The following information is provided for citations.

  • Article Title Lower Mississippi River
  • Luther Brown
  • Author Ron Nassar
  • Website Name Mississippi Encyclopedia
  • URL
  • Access Date April 6, 2020
  • Publisher Center for Study of Southern Culture
  • Original Published Date
  • Date of Last Update April 14, 2018