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4. FLOWS OF COLORADO RIVER Table 3 on pages 22 and 23 shows the estimated virgin flow of the Colorado River at Lee Ferry, Arizona for each water year from 1896 through 1991. Column (4) of the table shows the average virgin flow for any given year within the period computed through water year 1991. eolumn (5) shows the average virgin flow for a given year within the period computed since water year 1896. Column ( 6) shows the average virgin flow for each progressive ten -year period beginning with the ten-year period ending on September 30,1905. The difference between the virgin flow for a given year and the average flow over the 95-year period, 1896 through 1991, is shown in eolumn (7). Article III(d) of the eolorado River Compact stipulates that "the States of the Upper Division will not cause the flow of the river at Lee Ferry to be depleted below an aggregate of75,000,000 acre-feet for any period of ten consecutive years reckoned in a continuing progressive series beginning with the first day of October next succeeding the ratification of this Compact." Prior to the storage of water in the eolorado River Storage Project reservoirs, which began in 1962, the flow of the river at Lee Ferry in any ten consecutive years was greatly in excess of the 75,000,000 acre-feet required by the eompact. Beginning in 1962, eolorado River Storage Project reservoirs have regulated the river above Glen eanyon Dam. Table 4, on page 24, shows the historic flow at Lee Ferry for the period 1953 through 1991. The historic flow for each progressive ten-year period from 1953 through 1991, beginning with the ten-year period ending September 30, 1962, the commencement of storage in eolorado River Storage Project reservoirs, is shown in Column (3). In each consecutive ten -year period, the total flow equaled or exceeded the 75,000,000 acre-feet required by the eompact. The flow at Lee Ferry during the ten-year period ending September 30, 1991 was 128,075,000 acre-feet. 13