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Show APPENDIX VI VI-37 32 COLORADO HIYEH STOHAGL PROJECT provision for allowance. The corollary of a conclusion to provide nn allowance for computed deficiency is that the Secretary exercises the discretion to operate in a reasonable manner as he determines. Ptiriigrupl) (.»: The decision to coordinate and integrate necessarily eliminates secondary energy generation at Hoover. It is conceivable, of course, that if a situation occurs when1 both reservoirs are completely full and there happens to be an extremely high runoff year, such that water would otherwise spill at Hoover, then secondary energy as defined in the Boulder Canyon project general regulations could be generated. Paragraph 10 indicates the cutoff date of the filling criteria, and permits earlier cutoff than given in paragraph 2 if such action is warranted. This is desirable because it will likely be possible to obtain full system firm power generation with less than a full Glen Canyon. As soon as this becomes a fact it would be well to close off the filling criteria. Paragraph 11 is a notification that the flood control regulations at Hoover Dam will be applied in full recognition of the available capacity in tlie upstream reservoir. The effect of such recognition is to diminish the space which must be held in Lake Mead for the catchment of floods. Such action would, of course, influence cost allocations to be made under section 6 of the act of April 11, 1956. RESULTS OF THE PROPOSAL Analyses have been made to appraise the effect of applying these principles and criteria. Any such appraisal can, of course, only be indicative. However, the following results give some indication of the magnitude of deficiencies in Hoover generation which might occur. If it is assumed that a runoff sequence, such as happened in 1930 through 1952 (considered to be an adverse period) should recur starting in 1962, and allowing for increases in upstream depletions, it appears that over that 23-year period the amount of deficiency would be 9,566 million kilowatt-hours, or an average of 415 million idlowatt-hours per year. This is roughlj' 10 percent of the average Hoover firm energy for the same period. If we assume that runoff conditions such as occurred from 1922 to 1929, inclusive (considered to be a favorable period), occurred in the same sequence, there would be no deficiency in the 8-year period required to fill Glen Canyon Reservoir. If we assume that the sequence starting in 1942 and continuing through 1957 followed by a recurrence of 1922 through 1924 recurred, there would have been a deficiency in 12 of the 19 years, with the total deficiency being about 8 percent of the total Hoover firm. The period of years which might be involved in filling Glen Canyon under the proposal becomes of lesser significance when the reservoirs are coordinated and integrated for power production, as the objective then is maximum power production and not reservoir filling per se. The study made does show Glen Canyon filling in 23 years under the 1930 sequence, 19 years under the 1942 sequence, and 8 years under the 1922 sequence. The repayment studies for the upper basin project assume that throughout the period of "Glen Canyon filling" (1) there will be average runoff, and (2) firm generation at Hoover will be maintained to the extent it can be without (a) drawing Hoover below 17 million acre-feet, and (b) without drawing upon Glen Canyon storage for that |