“The Levee’s Gonna Break”

Flooding is widespread throughout the Mississippi River Basin which, with tributaries, drains much of the area between the Rocky and Appalachian Mountains to the Gulf of Mexico.

Three types of flooding can occur along the Mississippi River: a levee breaks, flooding of the land between the levees and the hills skirting the MS River (the batture), and backwater flooding as its tributaries back up.

There has been no unplanned break of a MS River levee since 1937. For many people, the absence of a 1927 MS River style flood has masked the greater risks portended by increased batture and backwater flooding. Levee breaks along the Missouri River in 2011 and now, 2019, may finally be gaining attention of Congress and the Corps of Engineers.

Water now flows much faster to the Lower MS River due to changes in land use coupled with Corps of Engineers changes to the rivers. During the rainy season, water cannot get from the Lower MS River to the Gulf of Mexico as fast as it arrives from upstream. The bathtub that is the MS River from Natchez to the Gulf has been backing up since the late 1990s.

The chart is a measure of water depth over 48’ each day the water exceeds that mark. The daily values are summed over each year and each decade. Since water spreads as it passes flood state and since velocity of the river increases with increased height, this measure greatly UNDERSTATES the change of actual water volume increase as depth increases. In other words, the 2010s decade is worse, relative to the other decades shown, than this chart indicates.

There has been more frequent and longer flooding of the batture below Natchez for over a decade. During heavy runoff, the MS River is preventing tributary drainage by the Yazoo and other rivers causing severe backwater flooding up to the Missouri River and beyond.

Years of increasing batture flooding has been a harbinger of more and worse backwater flooding, and both are harbingers of the potential for even more catastrophic flooding: a Mississippi River levee break.

The astounding increase is no news to those near the Lower Mississippi River though —“Some people on the road carrying everything they own” from “The Levee’s Gonna Break” by Bob Dylan.