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<br />RECREA nON WATER AND LAND NEEDS
<br />
<br />Type of Recreation
<br />
<br />1980 2000 2020
<br />(Cumulative Above Current -
<br />Millions)
<br />0.23 0.72 1.50
<br />
<br />Recreation Water (acre)
<br />Recreation Land
<br />Developed (acre)
<br />Primary Use but
<br />Undeveloped (acre)
<br />Activity Days
<br />Recreation Days
<br />
<br />0.37
<br />
<br />0.60
<br />
<br />0.15
<br />
<br />I. I 9
<br />174
<br />68
<br />
<br />2.81
<br />484
<br />186
<br />
<br />4.43
<br />854
<br />343
<br />
<br />FLOOD CONTROL AND EROSION
<br />PREVENTION
<br />
<br />Highly destructive floods have occurred in all eight
<br />subbasins and along the mainstem of the Missouri River.
<br />In general, floods are caused by snowmelt, heavy
<br />rainfalls, or ice jams; or a combination of any of these
<br />factors, Flood damages occur much more frequently in
<br />the lower portion of the basin because of a higher
<br />development of flood plains and a higher susceptibility
<br />of the area to intense rainfalls over broad areas, De-
<br />vastating floods have also originated in the western
<br />mountain areas, such as on the Sun and Marias rivers in
<br />1964. and on the South Platte River in 1965. Ice jams
<br />can occur on most of the perennial streams in the basin.
<br />Small tributaries have produced destructive floods in all
<br />parts of the basin,
<br />Based on the 1965 level of development, average
<br />annual flood damages for the entire basin are estimated
<br />to be $95.5 million. Thirty-five percent of these damages
<br />are associated with the Lower Missouri Subbasin.
<br />Average annual damages to other subbasins are progres-
<br />sively less upstream, with only 1.6 percent being
<br />assigned to the Upper Missouri Subbasin. With a 2020
<br />level of development, average annual flood damages for
<br />the basin are estimated to be $392.3 million. Average
<br />annual benefits (flood damages prevented) associated
<br />with existing flood control work at the 1965 and 2020
<br />levels of development are $105.5 million, and $579.1
<br />million, respectively.
<br />Streambank erosion is causing serious damage to
<br />about I 1,200 bank-miles of the basin's rivers, This
<br />represents about I percent of the total length of all
<br />channels not classified as gullies, Based on the current
<br />level of economic development, average annual damages
<br />due to streambank erosion are estimated to be $5. I
<br />miiiion. However, with projected economic develop-
<br />ment, these damages will increase to about $13.6 million
<br />annually by 2020 if no additional protection is provided.
<br />About one-half of these damages will occur in the
<br />Middle Missouri and Kansas subbasins, with the re-
<br />maining one-half spread evenly among the six other
<br />subbasins.
<br />
<br />6
<br />
<br />About 40,000 acres of land are damaged each year by
<br />gullies which would require project-type action to
<br />correct. Current average annual damages are estimated to
<br />be $ 15.4 million and, unless corrective measures are
<br />implemented, damages are estimated to increase to
<br />$50.4 million by 2020. About 83 percent of these
<br />damages will occur in the Lower Missouri and Middle
<br />Missouri subbasins.
<br />
<br />AVERAGE ANNUAL FLOOD AND EROSION DAMAGES
<br />
<br />Feature Unit 1980 2000 2020
<br />Flood Damages $I,OOO/year 152,535 241,270 392,260
<br />Gully Erosion $I,OOO/year 23.41 I 33,849 50,366
<br /> I ,000/ acre 2,041 2,041 2,041
<br />Stream bank
<br />Erosion $I,OOO/year 7,300 10,000 13,600
<br /> Miles 11,200 11,200 11,200
<br />
<br />NAVIGATION
<br />
<br />Commercial navigation is confined to the lower
<br />portion of the main stem of the Missouri River. The
<br />authorized navigation channel is from Sioux City, Iowa,
<br />to the mouth of the river near St. Louis, The effective
<br />season usually comprises about 8 months from April to
<br />December.
<br />Commercial barge traffic can be expected to increase
<br />from 1,078 million ton-miles in 1964 to 3,300 million
<br />ton-miles in 2020, an increase of 200 percent in 56
<br />years. About 70 percent of this increase can be expected
<br />by 1980 and over 95 percent by 2000. Water require-
<br />ments to maintain the authorized navigation channel are
<br />estimated to be 30,000 d.s, at Sioux City and 32,500
<br />c.f.s. at Kansas City, Flow during an 8-month period at
<br />30,000 c.f.s. amounts to a total volume of 14.5 million
<br />acre- fee 1.
<br />
<br />WATER QUALITY CONTROL NEEDS
<br />
<br />The principal elements of water pollution in the
<br />Missouri Basin are bacterial agents, organic waste matter,
<br />undissolved solids, dissolved solids, and temperature.
<br />The sources of bacterial and organic poilu tan ts con-
<br />sidered in this study were municipal and industrial waste
<br />discharges and animal wastes from major confined
<br />feeding operations. Undissolved solids pollutants include
<br />sediments, oils, and refuse from manufacturing proc-
<br />esses. Natural runoff contributes practically all of the
<br />dissolved solids in the basin's waters. A small fraction of
<br />the total dissolved solids is contributed in municipal and
<br />industrial wastes and irrigation return flows, but may
<br />add undesirable or toxic constituents. Most uses deplete
<br />the water and return or leave the dissolved solids. The
<br />resulting increase in dissolved solids concen tra tion is
<br />included among the pollution or water quality problems.
<br />Stream temperatures normally vary with the average air
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