The MRC is charged with prosecuting the comprehensive river management program known as the Mississippi River and Tributaries (MR&T) project, which was authorized through the Flood Control Act of 1928. The four major elements of the MR&T project are:
- Levees for containing flood flows;
- Floodways for the passage of excess flows past critical reaches of the Mississippi River;
- Channel improvement and stabilization to provide an efficient and reliable navigation channel, increase the flood-carrying capacity of the river, and protect the levee system;
- Tributary basin improvements for major drainage basins to include dams and reservoirs, pumping plants, auxiliary channels and pumping stations.
The MR&T project is the largest flood control project in the world, providing protection to the 36,000 square-mile lower Mississippi valley. The flood control features of the project are designed to control the “project flood’—the largest flood reasonable expected to occur. The MRC developed the present project flood in 1956 after a complete review of the adequacy of the MR&T project. The project flood is larger than the record flood of 1927. At Cairo, Illinois, the project flood is estimated at 2,360,000 cubic feet per second (cfs). The project flood is 11 percent greater than the 1927 flood at the mouth of the Arkansas River and 29 percent greater at the latitude of Red River Landing, amounting to 3,030,000 cfs at the latter location about 60 miles below Natchez, Mississippi.
The navigation features of the MR&T project seek to facilitate navigation and promote commerce on the nation’s most vital commercial artery. Waterborne commerce on the Mississippi River increased from 30 million tons in 1940 to nearly 500 million tons today. This heavy commercial traffic includes grains, coal and coke, petroleum products, sand and gravel, salt, sulphur and chemicals, and building materials among others. In addition, many pleasure craft from all parts of the country now use the Mississippi River for vacation and travel.
The MR&T project represents one of mankind’s most successful civil works projects and one of the wisest investments. Since the initiation of the MR&T project in 1928, the nation has received a $24 return for every dollar invested, not including positive environmental impacts. The remaining work to be completed will have an estimated 37 to 1 return on investment.