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<br />> <br />,;' .! <br /> <br />~ ) <br /> <br />might occur. If it is assumed that a runoff sequence, such as hap- <br />pened in 1930 through 1952 (considered to be an adverse period) <br />should recur starting in 1962, and allowing for increases in upstream <br />depletions, it appears that over that 23-year period the amount of <br />deficiency would be 9,566,000,000 kilowatt-hours, or an average of <br />415 million kilowatt-hours per year. This is roughly 10 percent of <br />the average Hoover firm energy for the same period. If we assume <br />that runoff conditions such as occurred from 1922 to 1929, inclusive <br />(considered to be a favorable period), occurred in the same sequence, <br />there would be no deficiency in the eight-year period required to <br />fill Glen Canyon reservoir. If we assume that the sequence starting <br />in 1942 and continuing through 1957 followed by a recurrence of 1922 <br />through 1924 recurred, there would have been a deficiency in 12 of <br />the 19 years, with the total deficiency being about 8 percent of the <br />total Hoover firm. <br /> <br />The period of years which might be involved in filling <br />Glen Canyon under the proposal becomes of lesser significance when <br />the reservoirs are coordinated and integrated for power production, <br />as the objective then is maximum power production and not reservoir <br />filling per se. The study made does show Glen Canyon filling in 23 <br />years under the 1930 sequence; 19 years under the 1942 sequence; and <br />8 years under the 1922 sequence. <br /> <br />The repayment studies for the Upper Basin project assume <br />that throughout the period of "Glen Canyon filling" (1) there will <br />be average runoff and (2) firm generation at Hoover will be maintained <br />to the extent it can be without (a) drawing Hoover below 17,000,000 <br />acre-feet and (b) without drawing upon Glen Canyon storage for that <br />purpose. If assumption (1) is retained but the proposed principles <br />and criteria are substituted for assumption (2) there would be no <br />adverse effect on Upper Basin payout. To the extent that combined' <br />system operation of Hoover and Glen Canyon would increase power <br />production over and above that resulting from the assumptions of the <br />current repayment analysis the Upper Basin payout would be benefited. <br /> <br />Application of even the adverse runoff cycles of 1930-1952 <br />results in storage at Glen Canyon to minimum power head of 6,500,000 <br />acre-feet in from two to three years. After power generation is <br />initiated at Glen Canyon the objective, as spelled out in the proposed <br />principles and criteria, is to produce the greatest practical amount <br />of power and energy from combined operation. The revenues from all <br />energy generated from the combined system in excess of that required <br />to meet the commitments outlined above for the firm power under the <br />Hoover Dam contracts would be credited to the Upper Basin project. <br />Thus, it is probable that with allowances for computed deficiency <br />and under integration, and with 1930-1952 runoff conditions the rate <br />of Upper Basin project payout would be somewhat slower for a brief <br />period with the possibility of offsetting gains in later operations. <br /> <br />The Bureau's proposal is an equitable and practicable ap- <br />proach that results in the best use of the natural resource--falling <br />water. <br /> <br />\ <br /> <br />8 <br />