The Mississippi River, which starts at tiny Lake Itasca in Minnesota, is the third largest drainage basin in the world covering 41% of the 48 continuous United States. The river has always been a threat to the security of the valley through which it flows. Major flooding in 1912, 1913, and 1927 destroyed millions of dollars of property. After the flood of 1927 Congress passed the Flood Control Act of 1928. This legislation authorized the Mississippi River and Tributaries (MR&T) project. This project oversees four major flood control methods: Levees, Floodways, Tributary Basin Improvements, and Channel Improvement and Stabilization.
After periods of high water, the Mississippi River's channel at many places is too shallow, too narrow, or too difficult for navigation. The goal of the MR&T project is to develop a river channel with the dimensions and alignment which will carry flood flows efficiently and be suitable for navigation.
Natural sandbars occur in the Mississippi River where the banks are wide and the channel shallow. These shifting sandbars clog the channel and make it difficult to navigate.
Note the levee setback construction behind the original levee. This costly work was required because the river was attacking an area with narrow batture that was only protected by a tree screen.
The New Orleans District has maintained continuous efforts to improve and stabilize the channel by constructing dikes, revetments, cutoffs, and dredging. The levee setback, as shown above, affords only temporary protection against the river. Once made, it is just a matter of time before the river threatens the relocated levee. To hold the river in the desired alignment and maintain the levee system, its banks are stabalized with revetments.
To view a video on how the river's banks are stabilized with revetments, click here.