Mississippi River.doc

Mississippi RiverFrom Wikipedia, the free encyclopediaJump to: navigation, searchFor the river in Canada, see Mississippi River (Ontario).Coordinates: 290913N 891503W / 29.15361N 89.25083W / 29.15361; -89.25083Mississippi RiverLower course of the Mississippi through New OrleansCountryUnited StatesStatesMinnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, LouisianaTributaries-leftSt. Croix River, Illinois River, Rock River, Ohio River-rightMinnesota River, Missouri River, White River, Arkansas River, Red RiverCitiesMinneapolis, MN, St. Paul, MN, Davenport, IA, St. Louis, MO, Memphis, TN, Baton Rouge, LA, New Orleans, LASourceLake Itasca1-locationItasca State Park, Clearwater County, MN-elevation1,475ft (450m)-coordinates471423N 951227W / 47.23972N 95.2075W / 47.23972; -95.2075MouthGulf of Mexico-locationPilottown, Plaquemines Parish, LA-elevation0ft (0m)-coordinates290913N 891503W / 29.15361N 89.25083W / 29.15361; -89.25083Length2,320mi (3,734km)Basin1,151,000sqmi(2,981,076km2)Dischargefor Baton Rouge, LA-average450,000cuft/s (12,743m3/s) 2Map of the course, watershed, and major tributaries of the Mississippi RiverDetailed map of Mississippi River tributary structureThe Mississippi River is the largest river system in the United States and the largest of North America.34 About 2,320miles (3,730km) long,5 the river originates at Lake Itasca, Minnesota and flows slowly southwards in sweeping meanders, terminating 95 river miles below New Orleans, Louisiana where it begins to flow to the Gulf of Mexico. Along with its major tributary, the Missouri River, the river drains all or parts of 31 U.S. states stretching from the Rocky Mountains in the west to the Appalachian Mountains in the east to the Canada-U.S. border on the north, including most of the Great Plains, and is the fourth longest river in the world and the tenth most powerful river in the world.The current form of the Mississippi River basin was largely shaped by the Cordilleran Ice Sheet of the most recent Ice Age. The southernmost extent of this enormous glaciation extended well into the present-day United States and Mississippi basin. When the ice sheet began to recede, hundreds of feet of rich sediment were deposited, creating the flat and fertile landscape of the Mississippi Valley. During the melt, giant glacial rivers found drainage paths into the Mississippi watershed, creating such features as the Minnesota River, James River, and Milk River valleys. When the ice sheet completely retreated, many of these temporary rivers found paths to Hudson Bay or the Arctic Ocean, leaving the Mississippi Basin with many features oversized for the existing rivers to have carved in the same time period. The Mississippi River Delta has shifted and changed constantly since the formation of the river, but the construction of dams on the river has greatly reduced the flow of sediment to the delta. In recent years, the Mississippis mouth has shown a steady shift towards the Atchafalaya River channel, but because of floodworks at the rivers mouth, this change of coursewhich would be catastrophic for seaports at the river mouthhas been held at bay.Hundreds of Native American tribes have depended on the Mississippi River and its tributaries for thousands of years. Although they knew the river by many different names, it was the Ojibwe word misi-ziibi, meaning Great River, or gichi-ziibi, meaning Big River, that ultimately gave the river its present-day name. European explorers reached the mouth of the river as early as the 1500s and 1600s. The river throughout history has served as the border for New France, New Spain, and the early United Statesits size and importance made it a formidable boundary as well as a strategic military location, and later, an important artery for steamboats to travel on. Writer Mark Twain was one of the most well-known figures on the river in this period. Even today, the river serves as partial boundaries for ten states, and most of its course can easily be seen on a political map. The Mississippi has also been known for great flooding events, especially in the twentieth century which experienced up to four 100-year floods. This has led to the construction of hundreds of miles of levees along nearly the entire course of the river, although they have not always succeeded to prevent the greatest floods.Throughout its history, whether for Native Americans, explorers, or modern commerce, the Mississippi has always been a major navigation route through the center of North America. In the 19th and 20th centuries, despite its slow current and relative depth, a series of dams were constructed on the river, one of the most notable of which is at St. Anthony Falls in Minneapolis. These dams facilitate navigation for a steady stream of barge traffic carrying agricultural products from the fertile Mississippi Basin to the Gulf Coast, and like the Columbia River, most of the Mississippi also is a cascade of reservoirs. Most of its big tributariesthe Missouri and Ohio Rivershave also been developed for navigation. However, the development of the 20th and 21st centuries has also come with environmental problems, the most infamous of which is the enormous Gulf of Mexico dead zone that extends hundreds of miles out to sea from the rivers mouth. Because of dredging activity to deepen the Mississippi River c