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Show would provide the maximum feasible amount of re- liable flood protection and control in areas along the Missouri River and most of the major tribu- taries. With economic expansion in the basin, fur- ther investigations will be needed to determine if better protection or management is warranted. Some of the units in the Missouri Basin Project of the Bureau of Reclamation will provide flood control benefits. Thus, in the Canyon Ferry, Boy- sen, Mission, and Yellowtail units in the upper basin, considerable storage will be provided that will aid in reducing high flows. Many of the 100 or more other projects will provide varying amounts of flood protection to downstream interests. Under flood control legislation, the Department of Agriculture has proposed a major agricultural program for the basin. This plan has been rec- ommended to Congress for adoption. Navigation In the early period of fur trade and mining, navigation flourished along the main stem up- stream to Fort Benton, Mont., and on some of the major tributaries. Settlement of the region par- alleled the river system, and important trade cen- ters were established on the banks of the river. With the coming of the railroads, navigation declined. The constantly eroding banks, shifting stream bed and sand bars, swift currents, and snags were hazards discouraging to competitive naviga- tion. Even though navigation on the river has been unimportant for some decades, some local and other groups have continued to press for naviga- tional development of the main stream. Railroad rates in the basin are higher than in many other parts of the country, and it is a widespread opin- ion in the basin that transportation costs have hin- dered development. Completed Works Legally the Missouri River is considered navi- gable from Fort Benton to the mouth. Many years ago some channel improvements were made over this entire reach. However, no cargoes have been carried above Sioux City for some years. Until 1945 the project depth of the channel as far as Sioux City was set at 6 feet, but this was never attained. Prior to the war, tows with a 5-foot draft could proceed upstream as far as Omaha, and experimental trips were made to Sioux City. Dur- ing the 1930's Fort Peck Dam was constructed, and the reservoir behind it placed in operation. This reservoir stores flood flows, and from it water has been released during low flow periods to maintain navigation below Sioux City, Iowa. Some navigation projects also were undertaken on the Gasconade and Osage Rivers, including a lock and dam on the latter. During World War II, cessation of maintenance caused much of the navigation channel to deterio- rate. This deterioration was accelerated by severe floods and ice jams, especially in the reaches above Kansas City. Authorized Program and Projects Under Construction In 1945 Congress approved a navigation program for the Missouri River from Sioux City to the mouth. The entire reach is considered part of a single project, of which the authorized channel depth is 9 feet. Improvement work consists of "permeable dikes" to direct the flow of the river, and thereby shorten and deepen the channel. Sedi- ments are deposited behind the dikes. When the river finally attains proper alinement, the banks are stabilized by quarried stone. The stabilization of the channel brought about by these works also helps to prevent bank erosion, and will help to protect levees which are part of the authorized flood control project. In 1950 the program of improvements was sched- uled for completion during the fiscal year 1959. A project has been authorized to create a harbor at the mouth of Big Sioux River to shelter boats during high floods, winter freezes, and dangerous ice-flow periods. The several multiple-purpose reservoirs on the main river above Yankton will regulate flow. Their operation in conjunction with Fort Peck will fur- nish a dependable water supply for navigation in the lower reaches of the river. Situation at End of Present Program Completion of the present program will provide a channel 9 feet deep and 300 feet wide as far up- stream as Sioux City. Wharves will be available at the necessary sites. Short navigable stretches will be available on the Osage and Gasconade Rivers. 183 |
