page_title: Mississippi River
section_title: Navigation and flood control
hierarchical_section_title: Mississippi River / Navigation and flood control
caption_attribution_description: English: Mississippi Ships on the lower part of the Mississippi
context_page_description: The Mississippi River is the second-longest river and chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it flows generally south for 2,320 miles to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between the Rocky and Appalachian mountains. The main stem is entirely within the United States; the total drainage basin is 1,151,000 sq mi, of which only about one percent is in Canada. The Mississippi ranks as the fourth-longest river and fifteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
  Native Americans have lived along the Mississippi River and its tributaries for thousands of years. Most were hunter-gatherers, but some, such as the Mound Builders, formed prolific agricultural societies.
context_section_description: A clear channel is needed for the barges and other vessels that make the main stem Mississippi one of the great commercial waterways of the world. The task of maintaining a navigation channel is the responsibility of the United States Army Corps of Engineers, which was established in 1802. Earlier projects began as early as 1829 to remove snags, close off secondary channels and excavate rocks and sandbars.
  Steamboats entered trade in the 1820s, so the period 1830–1850 became the golden age of steamboats. As there were few roads or rails in the lands of the Louisiana Purchase, river traffic was an ideal solution. Cotton, timber and food came down the river, as did Appalachian coal. The port of New Orleans boomed as it was the trans-shipment point to deep sea ocean vessels. As a result, the image of the twin stacked, wedding cake Mississippi steamer entered into American mythology. Steamers worked the entire route from the trickles of Montana, to the Ohio River; down the Missouri and Tennessee, to the main channel of the Mississippi. Only with the arrival of the railroads in the 1880s did steamboat traffic diminish. Steamboats remained a feature until the 1920s. Most have been superseded by pusher tugs. A few survive as icons—the Delta Queen and the River Queen for instance.
  A series of 29 locks and dams on the upper Mississippi, most of which were built in the 1930s, is designed primarily to maintain a 9-foot-deep (2.7 m) channel for commercial barge traffic. The lakes formed are also used for recreational boating and fishing. The dams make the river deeper and wider but do not stop it. No flood control is intended. During periods of high flow, the gates, some of which are submersible, are completely opened and the dams simply cease to function. Below St. Louis, the Mississippi is relatively free-flowing, although it is constrained by numerous levees and directed by numerous wing dams.
  On the lower Mississippi, from Baton Rouge to the mouth of the Mississippi, the navigation depth is 45 feet (14 m), allowing container ships and cruise ships to dock at the Port of New Orleans and bulk cargo ships shorter than 150-foot (46 m) air draft that fit under the Huey P. Long Bridge to traverse the Mississippi to Baton Rouge. There is a feasibility study to dredge this portion of the river to 50 feet (15 m) to allow New Panamax ship depths.
caption: Ships on the lower part of the Mississippi
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