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.... ~ . '. OaDJ78 WATER SUPPLY FOR THE SAN JUAN-,CHAMA PROJECT 3 ./";.' On the basis of a 22-year period of study from 1930 to 1952, during which the historical runoff at Lee Ferry averaged only 11.7 million acre-feet per year and assuming 21 million acre-feet of reservoir ca- pacity availa~le, Mr. Hill concluded that th~ ~ggregate depletion of the upper basIn could be no more than 6.2 mIllion acre-feet per year. Mr. Felix Sparks; Director of the Oolorado Water Oonservation Board, has furnished the committee a copy of the board's "Operation Study 0-1," dated May 8, 1961, which is an analysis of the Oolorado River flows at Lee Ferryfor the period 1922 to 1960. The study is based on historic flow at Lee Ferry rather than virgin flow and upper basin historic depletions are added later to excess flows in determining total water available for upper basin depletion. The historic flow at Lee Ferry over the period of study averaged 12,126,000 acre-feet annually. The average cumulative total in consecutive and successive 10-year periods was determined to be 119,851,000 acre-feet. With compact delivery to the lower basin of 75 million acre-feet in consecu- tive and successive 10cyear periods, the average actual excess delivery to the lower basin for the successive 10-year periods was determined to be-,44,851,000 acre-feet, Historic depletions in consecutive and successive, lO-year periods averaged 18,796,000 acre-feet. In the study, the actual excess over delivery requirement to the lower basin is then added to the upper basin historic depletions to determine the total amount of water available for upper basin depletion (except in any 10-year period where the total exceeds 75 million acre-feet, in which case 75 million acre-feet is used). This amount for consecutive and successive 10-year periods averaged 62,984,000 acre-feet. On an annual basis the average is 6,298,040 acre-feet. ~rick8on 8t~ie8 These studies were also referred to during the hearings, Theyare studies by Mr. John R. Erickson prepared by the State of Al'lzona and presented as. testimony in the Arizona v. California litigation. Studies were made for a special purpose and no claim is made that they represent a proper operation of the upper basin reservoirs. The first of these studies was submitted to the Senate committee during hearings in July 1958 by Mr. Raymond Matthews. The study appears on pages 174-177 of the printed hearings and is discussed on pages 166-168. The period of this study is 1909-56. The assump- tion is made that virgin flow at Lee Ferry of over 15 million acre-feet will be available to satisfy the Mexican treaty obligations. The study assumes 25 million acre-feet effective storage in reservoir capac- ity and 5,700,000 acre-feet annual depletion at Lee Ferry, Releases from Glen Oanyon are made without regard to power operation and range from 1,049,000 acre-feet to 13,928,000 acre-feet annually. The study results in releases at Lee Ferry amounting to an average of 9,511,000 acre-feet annually, net inflow to Lake Mead averaging 10,458,000 acre-feet annually, and sustained annual releases from Lake Mead averaging 9,600,000 acre-feet annually, Mr. Erickson's second study was filed with the committee during hearings in May of last year and appeal' on pages 84 and 85 of the printed hearings. The period of this study is. also 1909-56. Forty- three million acre-feet o( effective storage is assumed with 7,5 million acre-feet annual depletion at Lee Ferry and 75 million acre-feet released per lO-year period to the lower basin, plus spills.