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Show CHAPTER VI 109 To attain a minimum power pool at Glen Canyon Dam, the flow at Lee Ferry was restricted to 2,520,000 acre-feet in water year 1963 and 2,427,000 acre-feet in water year 1964. (A table showing the historic flows at Lee Ferry for water years 1953-1976 appears at the end of Chapter VII on "Operating Criteria.") Because of the tight water situation Secretary Udall on May 16, 1964, directed Lower Basin water users to reduce their water demands by 10 percent for the period of June through December 1964. It was anticipated this would save 400,000 to 500,000 acre-feet of water during the 1964 drought year. The Metropolitan Water District of Southern California was later exempted from this cutback. The Yuma County Water Users' Association, the Yuma Mesa and Bard Irrigation Districts attacked the legality of the cutback order but the Arizona Federal District Court upheld it. The water surface elevation in Lake Mead dropped to elevation 1098.6 on August 31, 1964, to 1093.5 on September 30, 1964, and to a low of 1088.1 in December 1964. From that low, with favorable runoff in the spring of 1965, it was restored to rated power head elevation of 1123 on June 23, 1965, more than a year after the Secretary's decision to modify the Lake Powell filling criteria. During June 1965, Lake Powell water surface rose from minimum power elevation of 3490 to about 3511 and the content increased about 1 maf (Annual Report, Colorado River Board of California, 1964-1965). By September 30, 1965, Lake Powell storage increased 2.25 maf over the storage on September 30, 1964, to a total of 8.64 maf at elevation 3530. The following statistics are pertinent: LAKE MEAD Elevation Content (Million acre-feet) LAKE POWELL Elevation Content (Million acre-feet) Normal High water 1222 27.3 Rated Head on Powerplant 1123 14.5 Min. Power pool 1083* 10.7 Nevada Pumps (Min. level) 1050 8.0 'Elevation below which turbines vibrate, excessive cavitation takes place Colorado River, Lee Ferry, April-July runoff forecast, May 1, 1964 3700 3600 3490 27 15 6.1 Lake Powell, March 26, 1964 3,120,000 acre-feet Lake Powell, May 8, 1964 2,576,000 acre-feet Additional storage needed for minimum power head at Lake Powell, 3.6 million acre-feet |
