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CHAPTER V11 (1) Revision or termination of the Filling Criteria, which, by its terms, is within the Secretary's discretion, and particularly cancellation of the deficiency payments. (2) Releases at Lake Powell above Compact minimum not to be construed as a precedent affecting the Upper Basin position respecting Treaty obligations and accounting for uses in the Lower Basin. (3) Releases at Lake Powell in early years above Compact minimum not to be a precedent for future deliveries. (4) A commitment that use of Upper Basin entitlement not be limited by criteria terms including prob- ability applications. (5) Upper Basin shortages not to be imposed by or result from criteria when Upper Basin uses are less than its entitlement. (6) Lower Basin uses and losses not to affect Upper Basin operations. (7) Criteria should be flexible. (8) Unequal remaining active space at minimum power levels, in Lake Powell and Lake Mead. (9) Economic advantages cannot be a factor in defining Operating Criteria. (10) Effective date of criteria to be spelled out. D.2 Lower Basin Views Arizona's views stressed no minimum elevations should be established for Lake Mead-not even the 1050 elevation for the Southern Nevada Water Project; that power production should be subordinate to water de- mand; and minimum releases from Upper Basin of 8.4 maf rather than 8.25 maf. California's views were that the Filling Criteria be continued, that no rule curve be used but that the Oper- ating Criteria should be general and that if alternative choices are available, power production should be max- imized pursuant to Section 7 of the Colorado River Storage Project Act. Nevada, in general, concurred with CaHf~omia's views. The problems as seen by the Task Force Chairman were: (1) How flexible to make the criteria? California stressed the need for flexibility and the difficulty of pre- dicting future water conditions, although Public Law 90-537 required more than a statement of principles. (2) Should Lake Mead be drawn down below elevation 1083 (10 maf storage), which is about the mini- mum level without incurring excessive turbine maintenance? Arizona said yes, while Nevada and Califor- nia opposed this. (3) Under what conditions should "surplus" water be released from Lake Mead for use in the Lower Basin above 7.5 maf? California favored a liberal rule on release of surplus water while Arizona seemed more restrictive. (4) What rule curve should be used to accumulate storage in the Upper Basin reservoirs? Reclamation's initial draft of criteria used the lowest years of record (1953-1956); i.e., the so-called 98.4 percent prob- ability. (The lowest critical period of record varies with the magnitude of Upper Basin depletion.) The critical period of record was then increased progressively to 12 water years, 1953-1964, then to 34 water years, 1931-1964. Other probability studies included the 98.4+ percent, which would protect the minimum power pool, as well as using no rule curve. The Upper Basin favored a high rule curve while the Lower Basin favored a low rule curve. (5) What should be the minimum annual release from Lake Powell? The Upper Basin opinion is that 75 maf in any period of 10 consecutive years is the limit of their obligation to deliver water at Lee Ferry. However, in the early years before full development in the Upper Basin a greater release will be made for power generation. Therefore, they acquiesced to Reclamation's use of 8.23 maf minimum annual release, provided this figure is not construed to be an obligation of the Upper Basin. (6) 1o the "Filling Criteria" terminate upon application of the "Operating Criteria"? The Upper Basin was united that this be done. The Lower Basin was opposed. E- California Drq/t On November 17, 1969, California submitted to the conference participants its draft of Operating Criteria and an explanation thereof. This was modified slightly for clarification purposes by letter dated November 25, A-4