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COLORADO RIVER COMPACT WATER DEVELOPMENT PROJECTION November 2, 1995 FINAL REPORT Page 13 which includes the maximum amount ever diverted in a single year by transmountain diversion projects, and updated values of municipal and industrial consumption prepared by the U.S. Geological Survey for 1985 was also computed; this value is approximately 2.6 MAF. In this context, Table 3b shows that Colorado has approximately 450,000 acre feet of its apportionment left to develop through full use of existing (but under-utilized) projects and the construction of new projects to reach the 3.079 MAF level of compact development. If Colorado chooses to develop more than 3.079 MAF of consumptive use, the risk of curtailment and associated socioeconomic disruption in the event of a future "compact call" increases. However, because of the uncertainty associated with Colorado's ultimate compact apportionment, the Workgroup felt the target for the upper limit of Colorado's consumptive use should still be 3.855 MAF. Endangered fish recovery instream flow protection by the CWCB should be done in a fashion which allows for the potential development of a full 3.855 MAF. VI. ALTERNATIVES CONSIDERED FOR DISTRIBUTING COLORADO'S REMAINING COMPACT APPORTIONMENT AMONG THE MAJOR SUBBASINS IN COLORADO In the course of our deliberations, a variety of alternative scenarios for "allocating" Colorado's unused apportionment among the subbasins were considered. We have not been asked, or authorized, to make a legal or policy determination of who would be entitled to the water or how a potential compact call might be administered. Rather, we have attempted to estimate the overall pattern of future water development by basin which might occur. The following is a summary of our overall thought process. The alternatives reviewed are adequately reflected in the summaries of our meetings, and will not be explained in detail here in order to keep this document to a readable length. Many alternatives were considered, and approximately ten were evaluated in some detail. The development of alternatives began with a brief review of the CWCB staff work in November 1991, in which the suggested approach was to distribute the remaining compact apportionment based on the potential development of conditional water rights in priority. It was noted that there was approximately 3.9 MAF of decreed absolute storage on the western slope of Colorado and about 4 times that amount in conditional storage decrees, which is easily enough to exhaust the natural water supply. It was also noted that conditional water rights do not necessarily represent actual demands. These factors created a large amount of uncertainty about the development of conditional water rights and which ones would or would not be developed, thus, the approach was abandoned. The next set of alternatives considered different ways of distributing the remaining compact apportionment in a logical fashion, such as based on the fraction of natural flow originating in a given basin, or allowing all remaining apportionment to be developed in any basin. Although these approaches might be more equitable, they might not be realistic and they were not pursued after initial evaluations.