September 26, 2016
Here in Memphis our great bluff offers protection from high water of the Mississippi River, but many people along lower Mississippi River rely heavily on the network of thousands of miles of levees to protect land along the river and some of its tributaries. The levee system is considered a nationally treasured engineering project. This March, the Mississippi River Commission reported that these levees have prevented $666 billion in flood damages since 1879.
Levees of varying forms have been along the Mississippi River for hundreds of years. The river’s first levees were naturally made from sediment that gathered on the banks of the river and were no more than a couple of meters high. Jean-Baptiste Le Moyne de Bienville, founder of New Orleans, initiated the first man-made levee in the United States nearly 300 years ago in 1717. The levee was modeled after those in Bienville’s home country of France. The flood control plan at that time was a fend-for-yourself strategy as the French government ordered land owners adjacent to the river to build and maintain their own levees. Land owners opting not to do this relinquished their rights to the land to France.
As can be imagined, this piece-milled management system was uncoordinated, and subsequent levee failures resulted in lost lives and major property damage. Once the United States had control of the lower Mississippi River following the Louisiana Purchase of 1803, the Army Corps of Engineers took command of the levees and still manages today. Initially, a lack of coordination among the states that were charged with managing their own portions of the levees continued. Although each state did standardize levee construction within its jurisdiction, varying specifications such as the height or degree of slope of the levee weakened the system’s effectiveness. The Army Corps of Engineers eventually standardized maintenance and construction through interventions from Congress. Another issue that had to be resolved was created by the levee system itself. Flooding reached higher heights as the waterway became increasingly constricted while levees grew in size and number. This led to a series of heightening of across the system.
Check out the diagrams below that outline the different ways that levees can fail and show some specifics on levee designs.
Sources: Kemp, K. (n.d.). The Mississippi Levee System and the Old River Control Structure. Retrieved September 22, 2016, from http://www.tulane.edu/~bfleury/envirobio/enviroweb/FloodControl.htm
U.S. Army Corps of Engineers. (n.d.). MISSISSIPPI VALLEY DIVISION. Retrieved September 22, 2016, from http://www.mvd.usace.army.mil/About/Mississippi-River-Commission-MRC/Mississippi-River-Tributaries-Project-MR-T/Levee-Systems/ U.S. Army Corps of Engineers. (n.d.). National Levee Database - Maps. Retrieved September 22, 2016, from http://nld.usace.army.mil/egis/f?p=471:32:6053512229707:LOAD_SEARCH:NO:32