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<br />for justification of a water supply for the Central Arizona Project authorized in <br />1968. <br /> <br />(6) The estimated average annual virgin flow during the 1914-2002 period is 14.7 <br />million acre-feet. This period is an extension of the 1914-1965 period used in <br />the Upper Colorado Region Comprehensive Framework Studies of 1971. The <br />average annual virgin flow for the 1914-1965 time period is 14.6 million acre- <br />feet. <br /> <br />(7) The average annual virgin flow for the period 1914-1945 is 15.6 million <br />acre-feet. This was the period of record used by the negotiators of the Upper <br />Colorado River Basin Compact of 1948. <br /> <br />(8) For the period 1922-2002, which is the period of record since the signing of the <br />Colorado River Compact, the average annual virgin flow is 14.3 million <br />acre-feet and the average annual historic flow is 11.0 million acre-feet. <br />Records for this series of years are based upon actual measurements of flows <br />at Lees Ferry. The ten-year moving average flow since 1922 is considerably <br />less than the ten-year moving average flow prior to 1922. <br /> <br />(9) Two completely unrelated ten-year periods of minimum flows have occurred <br />since 1930. During these periods, 1931-1940 and 1954-1963, the average <br />annual virgin flow amounts to only 11.8 million acre-feet. <br /> <br />(10) For a 12-year period, 1953-1964, the average annual virgin flow amounts to <br />only 11.6 million acre-feet. <br /> <br />(11) Since Glen Canyon Dam was closed in 1963, the estimated virgin flow for the <br />subsequent 39 years is 14.6 million acre-feet. The estimated historical flow for <br />the same period (1963-2002) is 9.9 million acre-feet. <br /> <br />26 <br /> <br />, <br />, <br />