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<br />. <br /> <br />. <br /> <br />ou~547 <br /> <br />The Colorado River Basin states unanimously support s. <br />1696 for an extremely important reason--it will assist in <br />assuring the future availability of water supplies in these <br />states of the arid southwest. The Colorado River Floodway as <br />defined in this legislation is consistent with the effective <br />and balanced management of the river and with the protection <br />of human life, property, and natural resources. These <br />objectives would be achieved through the legislation without <br />detrimental environmental impacts and with better maintenance <br />of the presently-established multiple uses of the river's <br />resources than through other alternatives. Alternatives for <br />greater flood protection through smaller flood control <br />releases would require construction of additional water <br />storage facilities to replace the amount of conservation <br />storage that would be dedicated to flood control space. <br /> <br />Background <br /> <br />The Colorado River reaches peak flow rates in excess of <br />100,000 cubic feet per second (cfs) in the late spring about <br />once every 3 years, on the average, due to snowmelt runoff. <br />Prior to construction of Hoover Dam, these high flows caused <br />correspondingly high levels of damage to the river banks and <br />riparian lands along the lower Colorado River. Since the <br />completion of Hoover Dam in 1935, the annual snowmelt floods <br />have been controlled, first by Lake Mead and later by the <br />upstream reservoirs as they were constructed. <br /> <br />The maximum flood control release objective for Hoover <br />Dam since its closure has been 40,000 cfs. During the 48- <br />year period from 1935 through 1982, releases from Hoover Dam <br />exceeded 25,000 cfs in only 2 years, and never exceeded <br />.36,000 cfs. From 1935 to 1962, this high degree of control <br />was possible because the low level of downstream consumptive <br />use requirements did not require a large amount of carry-over <br />storage to meet water requirements during an extended dry <br />period. Under those conditions, it was possible to operate <br />Hoover Dam to meet demands and keep the water in storage low <br />enough that the annual snowmelt inflow could be captured <br />without risking use of the maximum controlled release <br />capability of Hoover Dam (73,000 cfs without use of the <br />spillways). After 1963, with the completion of Glen Canyon <br />Dam, and until 1980, all streamflow in excess of downstream <br />consumptive use requirements was retained to fill Lake <br />Powell's vacant storage capacity. <br /> <br />With the filling of Lake Powell in 1980, releases in <br />excess of downstream delivery requirements were made from <br />Hoover Dam but the peak rate reached only about 21,000 cfs <br />until 1983. However, with the currently-filled condition of <br />the reservoirs, and with the consumptive uses of the Basin <br /> <br />-2- <br />