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<br />8. Below Sioux City the hluffs along the valley are steeply rolling
<br />to nearly vcrtical and rise from 150 to 300 feet above the valley
<br />floor. The vallev width varies from 1)) to 17 miles. The average
<br />width of the vafIey is about 5 miles. The valley-floor elevat.iollS
<br />vary from approximately 420 feet mean sea level at the mouth to
<br />approximately 1,100 feet mean sea level at Sioux City.
<br />9. The avcrage rainfall for the area hetween Siom; City, Iowa, and
<br />the mouth varies from about 26 inches at Sioux City to about 40
<br />inches near the mouth. The regimen of the Missouri River is oharac-
<br />terized bv wide variations between nHl.A-;mum and minimum dis-
<br />charges. "In the reach of the river bctween Sioux City, Iowa, and
<br />t.he mouth, record~ of river stages are available since 1872. However,
<br />except for the period 1879 to 1891, discharge measurements have heen
<br />obtained at stations along this reach of the river only since about 1928.
<br />10. The area along the Missouri River between Siou.x City, Iowa,
<br />and the mouth is predominately agricultural. Dairying and truck
<br />gardening ore carried on extensively near the large municipalities,;
<br />In the larger municipalities there is considerable industrial develop-
<br />ment. The area has well-developed railroad and highway facilities.
<br />There is an existing 6-foot navigation project from Sioux City, Iowa,
<br />to the mouth. Commercial navigntion has been carried 011 below
<br />Kansas City, Mo., for many years alld to Omaha, Nebr., for several
<br />years prior to the war. Several commercial towbont8 formerly operat-
<br />ing on the Missouri Rive,r have recently been withdrawn for use on
<br />the Mi..issippi and other inland waterways to assist in relieving the
<br />critical traIlsportat.ion problems in the Enst. However, when towing
<br />equipment is available water-borne trallSportation will be availnble
<br />to the entire area under invest.igation.
<br />11. Patinent existing and authorized Federal projects.-The existing
<br />navigation project between Sioux City, Iowa, and the mouth resulted
<br />from authorization contained in nets of Congress dated July 25,
<br />1912; August 8, 1917; March 3, 1925; and Janllary 21, 1927. The
<br />exiscing project provide" for securing a navigable channel with a
<br />minimwn low-water depth of 6 feet, hy means of bank revetment,
<br />permeable dike" to contract and stabilize the waterway, removal of
<br />snags, and occasionnl dredgiug. The project is about 97 percent
<br />complete hetweell Kansas City. Mo., and the mouth, and abollt
<br />90 percent complete between Sioux City, Iowa, and Kansas City,
<br />Mo. Further new construction hus beell deferred in order to con-
<br />serve critical materials and manpower for the war effort. The,
<br />navigation works, although not completed, have already st.abilized
<br />the banks of the river, eliminated the constant shifting of the channel,
<br />and greatly reduced bank erosion.
<br />12. The Fort Peck Dam in Montnna was authorized b the River
<br />and ar or ct 0 . llD'USt 1 5. 1e ort ec { am WIt a
<br />ross fe-servo ell ReILY 0 a 011 t I 5 (0 ncre- eet wos constructe
<br />1"lIllUfl 0 a.sSUl'lIl a e uate nl\.Vl u. ,lOll
<br />Ie am W'"f1.S essentrn y comp etcd Ill. ?;J9. The reservoir is operated
<br />to store excess wat,er during the high-wlttrer season for Inter release to
<br />J :augment t,}1e flow durin~ low~water periods. A hydroeleet.ric power
<br />pJallt at the Fort Peck Unm was authorized by the act of Congress
<br />o~J\Iay 18, 1938. On ,Tnne 30, 1943, one 35.000 kilowatt unit was
<br />pn;ced in operati?n. Opel'llt.ion of t.he project not onIy provides
<br />\\>jater fO.f navIgn.tlOll and the generatIOn of pow,,~r for lrngatlOll and
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<br />MISSOURI RI\'ER BASIN
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