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<br />Missouri River Basin
<br />
<br />Description. The Missouri River forms the
<br />eastern and part of the northern boundaries of
<br />the state. The river arises in Montana with the
<br />junction of the Jefferson, Gallatin, and Madison
<br />rivers at Three Forks, Montana. It flows for 2,31 5
<br />miles in a southeasterly direction to its junction
<br />with the Mississippi River above St. Louis,
<br />Missouri. The drainage area of the Missouri River
<br />Basin includes all of Nebraska, most of Montana,
<br />North and South Dakota, and Wyoming, about
<br />half of Kansas and Missouri, smaller parts of
<br />Colorado, Minnesota and Iowa, and some terri-
<br />tory in Canada.
<br />The topographic features of the basin can be
<br />divided up into three major groups: the Rocky
<br />Mountain system; the Interior Plains, including
<br />parts of the Great Plains and Central Lowlands,
<br />which encompasses all of Nebraska and a major
<br />portion of the basin; and the Interior Highlands,
<br />characterized by the Ozark Plateaus region in
<br />Missouri. The Interior Plains generally have a flat
<br />to gently rolling topography. The Black Hills of
<br />South Dakota and the Sandhills of Nebraska are
<br />distinct topographic features in the Great Plains
<br />section. Major tributaries to the south and west
<br />include: the Yellowstone, Little Missouri,
<br />Cheyenne, Niobrara, Platte, Kansas, Osage, and
<br />Gasconade rivers; to the north and east are the
<br />Milk, James, Big Sioux, Little Sioux, Grand, and
<br />Chariton rivers. The Missouri River and its tribu-
<br />taries drain approximately 328.5 million acres
<br />within the United States.51
<br />The average annual precipitation in the basin
<br />varies from over 35 inches in the Rocky
<br />Mountains on the western edge to about 14
<br />inches on the Great Plains, about 26 inches on
<br />the Central Lowlands, and over 36 inches in the
<br />Ozark Highlands. The weather in this mid-contin-
<br />ent location, however, is known for its wide fluctu-
<br />ations and extremes. It has been estimated that
<br />about 70% of the precipitation comes as rainfall
<br />during the growing season.52
<br />Abnormally high and low streamflows often
<br />result from wide fluctuations in natural runoff.53
<br />The mean annual discharge at Sioux City is
<br />21,212,934 acre-feet and at Omaha is
<br />21,611,819 acre-feet. Below the junction of the
<br />Platte River with the Missouri River, the mean
<br />annual discharge is 28,776,226 acre-feet at
<br />Rulo.54
<br />There are six major main stem reservoirs on the
<br />Missouri River, all multi-purpose projects con-
<br />structed by the U.S. Army Corps of Engineers.
<br />Fort Peck Reservoir, located in Montana, was
<br />completed in 1937. The remaining main stem
<br />reservoirs were authorized as part of the Pick-
<br />Sloan Plan which was included in the Flood
<br />
<br />1-26
<br />
<br />Control Act of 1944. They are Sakakawea (North
<br />Dakota), Oahe (South Dakota), Sharpe (South
<br />Dakota), Francis Case (South Dakota), and Lewis
<br />and Clark (Nebraska and South Dakota). The
<br />Pick-Sloan Plan was designed to provide an
<br />irrigation water supply, flood control, hydro-
<br />electric power generation, navigation, recre-
<br />ation, fish and wildlife enhancement, and in-
<br />dustrial water supply. A number of other projects,
<br />primarily for irrigation development and author-
<br />ized by the 1944 Flood Control Act, have been
<br />constructed or are in various stages of planning.
<br />A third major provision of the Pick-Sloan Plan
<br />was the continued development of navigation on
<br />the Missouri River, supported by releases from
<br />the main stem reservoirs and inflows from trib-
<br />utaries. A nine foot deep channel, 300 feet wide,
<br />is maintained for 732 river miles from Sioux City,
<br />Iowa to the mouth of the river at St. Louis,
<br />Missouri, usually from April 1 through December
<br />1. 55 The navigation channel was authorized by
<br />Congress in the Rivers and Harbors Act of 1945
<br />and is currently maintained by the U.S. Army
<br />Corps of Engineers. Streamflow for navigation is
<br />generally maintained at a minimum of 30,000 cfs
<br />during the spring, summer, and fal1.56
<br />I nterstate Arrangements. There are at the
<br />present time 8 interstate compacts, 1 inter-
<br />national treaty, and 2 interstate decrees con-
<br />trolling some of the tributary waters of eight of
<br />the basin states; however, no similar legal agree-
<br />ments currently exist for the Missouri River itself.
<br />The Missouri River Basin Water Resources
<br />Plan recognizes that there are some legal and
<br />institutional problems associated with current
<br />issues in the basin. The report states that,
<br />Legal responsibilities, in many cases, are
<br />reasonably clear. However, as in other parts
<br />of the country, institutional arrangements
<br />for resolution of current issues in this Basin
<br />often lag the technologic technologic and
<br />financial means for implementation. Current
<br />examples are proposals for coal-slurry pipe-
<br />lines and other lines of transport that would
<br />cross several state and hydrologic bound-
<br />aries; water marketing from main stem res-
<br />ervoirs for industrial purposes; allocation of
<br />scarce ground water resources; and de-
<br />termination of Indian and federal reserved
<br />water rights. There are many questions of
<br />availability and alternative uses of water
<br />that focus on the need for advance study to
<br />guide efforts in the equitable allocation for
<br />consumptive use of water, yet making pro-
<br />visions also for needed reservations for in-
<br />stream uses.57
<br />Indian and federal reserved water rights are a
<br />major issue in the basin due to the large Indian
<br />and federal reservations located in the region.
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