home :: North America :: USA :: Geography :: Lakes, Rivers, and Coastlines :: Major Lakes and River Systems :: Major Rivers :: Missouri River
Major Rivers, Missouri River
major tributary, Ohio rivers, sandbars, drainage basin, Missouri River valley
The 3,726-km (2,315-mi) Missouri River, which originates in the mountains of northern Montana, is a major tributary of the Mississippi. Its drainage basin encompasses most of the northern Great Plains region. Along with the Mississippi and Ohio rivers, the Missouri served as a major water highway, carrying settlers into the interior regions as the frontier expanded westward. However, larger vessels could not use the Missouri because of shifting currents and sandbars.
In 1944 the U.S. government established the Pick-Sloan Plan to improve the Missouri River. The plan addressed the different needs of the two parts of the drainage basin. The western reaches of the river basin receive very little rainfall, less than 380 mm (less than 15 in) per year. In contrast, the eastern end receives more than 1,000 mm (more than 40 in) of rainfall annually. Residents of the western area wanted irrigation systems and reservoirs for storing water. People living in the eastern part of the river valley were interested in hydroelectric power, flood control measures, and improvement of navigation.
The Pick-Sloan Plan called for regional land management, the construction of reservoirs and irrigation projects, improvement of river navigation, and flood control infrastructure along the Missouri River valley. However, the government never implemented a comprehensive plan for the Missouri River valley. Instead it gradually completed individual projects, including the construction of six dams to provide irrigation water, and to regulate water levels in the navigation channel.
During the 1950s and 1960s, as part of the Pick-Sloan Plan, the channel of the Missouri was improved to accommodate high volumes of modern river traffic. Despite a tremendous investment in dams, reservoirs, and other engineering projects, commercial traffic on the Missouri has remained light.
Article key phrases: