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<br />Actual Operations Under Criteria - Water Year 1992 <br /> <br />Water year 1992 can be characterized by a wide variation in <br />water supply conditions within the has in. Basinwide <br />precipitation during 1992 was almost 90 percent of average <br />with tributary river basin precipitation ranging from 60 to 150 <br />percent of the 25 year average. Although precipitation was <br />nearly normal basinwide, it did not translate into normal <br />snowpack or runoff. In early faU of 1991, snowpack levels were <br />well above average throughout the basin. As the snow <br />accumulation season continued, a pattern of southerly storms <br />developed. This left the northern portion of the basin with <br />extremely low snowpack levels, and the southern portion of <br />the basin with slightly above normal levels. <br /> <br />Unregulated inflow into Lake Powell was only 4.2 million <br />acre-feet or 52 percent of average during April through July <br />1992. This resulted in the continued drawdown of the <br />Colorado River System reservoirs. The October 1, 1992, <br />Colorado River system vacant space was 19.7 million <br />acre-feet. Agrregale Colorado River live storage at Ihe end of <br />the year was 41.2 million acre-feet. Aggregale storage <br />decreased ill water year 1992 by 1.0 million acre-feet. This <br />large vacant space is a result of the lowest 6 com.ecutive )'ea.t'& <br />of inflow on record (1987 through 1992) into Lake Powell. <br />During this drawdown period, all deliveries of water to meet <br /> <br />obligations pursuant to "The Law of the River" have been <br />maintained. <br /> <br />Total releases from Glen Canyon Dam (deliveries from the <br />Upper Basin to the Lower Basin) for water year 1992 Were <br />8.23 million acre-feet. The 1992 operation plan allowed Ihe <br />water needs of the Lower Basin states to be satisfied, up to 7.5 <br />million acre-feet of beneficial consumplive use, during the <br />calendar year. <br /> <br />During water year 1992, Mexico received a total delivery of <br />about 1,403,000 acre-feet at Ihe Northerly International <br />Boundary (NIB). Of the 1,403,000 acre-feet of <br />Colorado River water reaching the NIB, about <br />343,000 acre-feet were delivered through the Pilot Knob <br />Power plant and Wasteway from the All-American Canal. An <br />estimated 385,000 acre-feet were released Ihrough <br />Laguna Dam. The remainder of the flow at the NIB was made <br />up of return flows to Ihe Colorado River below Laguna Dam. <br /> <br />2 <br />