Who is in charge of maintaining the Mississippi River and preventing flooding?

The United States Army Corps of Engineers (USACE) is a U.S. federal agency under the Department of Defense and a major Army command made up of some 37,000 civilian and military personnel, making it one of the world's largest public engineering, design, and construction management agencies. Although generally associated with dams, canals and flood protection in the United States, USACE is involved in a wide range of public works throughout the world.

The Engineers were first called upon to address flood problems along the Mississippi River in the mid-19th century. They began work on the Mississippi River and Tributaries Flood Control Project in 1928, and the Flood Control Act of 1936 gave the Corps the mission to provide flood protection to the entire country.