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COLORADO RIVER COMPACT WATER DEVELOPMENT PROJECTION November 2, 1995 FINAL REPORT Page 12 Table 2 Consumptive Use Entitlement Upper Basin Water Supply Mexican Treaty Obligation Upper Basin Apportionment Colorado's Apportionment 7,500,000 7,500,000 6,750,000 o 750,000 750,000 7,500,000 6,750,000 6,000,000 3,855,375 3,467,250 3,079,125 A hydrologic determination conducted by the U.S. Bureau of Reclamation in 1988 found that under the "Criteria for Coordinated Long-Range Operation of Colorado River Reservoirs" and considering the critical drought period (i.e., a drought period between 1954 and 1966) that there were only 6.0 MAF available to the Upper Colorado River Basin. Using this 1988 estimate, Colorado's annual consumptive use entitlement on average maybe only 3,079,125 acre feet. Therefore, on a long-term average annual basis, Colorado may only be entitled to use between 3.079 MAF and 3.855 MAF of the approximately 10,797,700 acre feet originating in Colorado, and the remainder must flow out of the State to meet downstream compact requirements. However, until full compact development occurs in other states, Colorado could use in excess of this amount on a temporary basis. But, Colorado also needs to be aware it could be taking significant risks if it makes extended use of more than 3.079 MAF annually. As a result, we have considered a range of development opportunities based upon these different estimates (i.e., 3.855 MAF, 3.467 MAF, and 3.079 MAF). V. COLORADO'S CURRENT CONSUMPTIVE USES AND REMAINING COLORADO RIVER APPORTIONMENT The Colorado River Basin Project Act directs the Secretary of the Interior to make reports on the annual consumptive use and loss of water from the Colorado River system. The most recent such report was prepared by Reclamation for the 1981-1985 period. Table 3a shows the state's 1981-85 average, maximum and adjusted maximum consumptive use of water by major tributary basin and type of use in Colorado. While this information is currently in the process of being updated, the updated information is not sufficiently completed to be useful at this time. Suffice to say at this point that new projects have been built since 1985 and that existing projects are being more fully utilized. During the 1981-85 period, Colorado's consumptive use of Colorado River water averaged 2.3 MAF annually. The maximum consumptive use which occurred during the period was approximately 2.5 MAF. An "Adjusted Maximum Consumptive Use" value,