The Missouri River

The Missouri River runs 2,341 miles through the US states of MT, ND, SD, NE, IA, KS, & MO. Much of its course has been altered by artificial dams and levees.



Stretching from the Centennial Mountains near Brower's Spring, Montana to meet up with the Mississippi River near St. Louis, Missouri, the Missouri River is one of the longest rivers in North America. Together with the Mississippi River, the Missouri River is part of the fourth longest river system in the world, just behind the Nile, Amazon, and Yangtze systems. Its highest elevation is 9,396 feet above sea level at the Continental Divide, and it passes through seven states before dumping into Spanish Lake just north of St. Louis. The Missouri River is fed from a watershed area covering portions of ten U.S. states, as well as parts of two Canadian provinces.

Historical Role

As a major waterway and a tributary of the Mississippi River, the Missouri River had served an important historical role in the expansion into the American West. However, it had been providing transportation and food sources for early Native Americans inhabiting the watershed region well before the "white man's" arrival. So called "Buffalo" (American bison) roamed nearby the nomadic native tribes of the region. Fur trading grew along the waterway as tens of millions of these bison fed in the Missouri River Basin, and Native Americans and Whites alike hunted them for profit in the 19th Century. Lewis and Clark were the first explorers to travel the entire length of the river, and refuted the claim that the Missouri was part of the Northwest Passage connecting the Atlantic to the Pacific. The mountains at the Continental Divide dashed any hopes that the waterway would continue on into the Pacific. Despite its "limited" range, the Missouri nonetheless provided invaluable transportation to Native Americans and, later, to pioneers heading West. Most trails that traversed the West had their start from the Mighty Missouri, including the Oregon, Santa Fe, California, Mormon, and "Pony Express" (for mail distribution) Trails. Even steamboats found a place on the waterway, but the lifespan of a ship on the Missouri was less than five years, due to inconsistent water levels and sedimentary-filled passages that prevented a clear view of the bottom of the river, and thus resulted in many groundings. The introduction of the Transcontinental and Northern Pacific Railroads sounded the end of the steamboat era, as people now moved across the West with great speed pulled by iron horses.

Modern Significance

Today, nearly the entire length of the Missouri River has been altered through a comprehensive system of dams, levees, dikes, and other flood-prevention devices. Construction for these engineering alterations largely began in the late 1940's, and continued for decades, many as part of the Flood Control Act of 1944. Only approximately 100 miles of the river, that along the Nebraska-South Dakota border, remains free-flowing still today. Hundreds of dams along the stretch of the river provide hydroelectric power used for such purposes as urban development and crop irrigation. After the rise of the railroads in the region, transportation by ship did not gain momentum again until the early 20th Century, when the river was significantly engineered to permit more efficient water transport. By 1929, it is estimated that approximately 15 million tons of total goods had been shipped on the river. By 1994, that number increased to 683,000 tons annually, and has remained more or less consistent, per statistics through 2006. Commodities that find their way across the country via the Missouri River include lumber, oil, produce, and numerous manufactured items.


The River has been traditionally the home to numerous species of fish, including the Pallid sturgeon. These are in addition to birds that nest their young in the habitats available in the watershed regions, as well as freshwater shellfish such as crayfish. Mammals in the Missouri's watershed include beavers, muskrats, raccoons, minks, and freshwater otters. The World Wildlife Fund for Nature (WWF) denotes that three distinct ecological regions can be found in the Missouri's watersheds. The Upper Missouri has shrubs and steppe-like grasslands, the Central Prairie experiences large seasonal climatic variations and has the highest diversity of flora and fauna, and the Lower Missouri has temperate grasslands and forests.

Threats and Disputes

Man-made changes to the Missouri River have significantly altered its natural state and continue to do so. The Missouri no longer flows warm and slow, but instead cuts sharp turns, with its dammed channels giving rise to fast-flowing currents. This has threatened the ability for various species to rest and reproduce. Dammed waterways oftentimes create water levels too shallow for spawning or even survival. Higher flow rates of sediment create sandbars by separating out the gravel and pushing it downstream. This has long been forcing birds to nest on the sandbars, and the natural nesting processes are inhibited in turn. Floodplains that once housed an entire ecosystem have been replaced by agricultural and urban development, and prospective levee breaks threaten large populations of humans and wildlife alike.


More in Environment