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<br /> <br />" <br />Left IlIplllway medl.ln;P;tlon7Gle~ Canyon o.m. <br /> <br />It became evIdent. when Inflow Into Lake <br />Powell did not begin to recede on or about <br />June 7 I 1hat the forecast was too low. <br />Subsequent precipitation In June and <br />reevaluation of runoff and snowpack <br />conditions resulted In the foracast being <br />raised to 11.3 million acre-teet on June 14, <br />13.3 million acre-faat on Juna18, and Ilnally <br />to 14.6 million acre-feet on June 22. <br /> <br />MaJor changes In the proJectad plan of <br />operations were required to accomodate this <br />unexpected and near record-breaking In flaw . <br />Large flood control releases were made from <br />the major storage reservoirs as they filled to <br />capacity and began to spill In lata June and <br />aarly July. <br /> <br />Th. maximum dally ral.a..s during the 1983 <br />Iloodlng were 92,800 cubic feet per second <br />[cfs) from Glen Canyon Dam, 50,800 cIs from <br />--laDver Dam, 45,100 cfs from Davis Dam and <br />IO,300cfafrom Parker Dam. Theres8rvolr <br />Iystem was operated In full accordance with <br />Istabllshed operating criteria and Corps of <br />:nglneers flood control regulations, and was <br />,ffectlve In reducing a peak runoff of <br />Ipproxlmately 128,000 cfslnto upstream <br />eservolrs to flows less than levee design <br />apaclty along the lower Colorado River. <br /> <br /> <br />Actual water supply In the Colorado River <br />Basin during water year 1983 turned out to be <br />180 percent of the long~t8rm average, ranging <br />from 200 percent In the Green River above <br />Flaming Gorga Dam to 114 percent In the <br />Gunnison River above Blue Me8a Dam. <br />Aggregate Colorado River 8torage at the end <br />of the water year was 58,962,000 acre-feet, <br />representing an Increase of 4,932,000 <br />acre-feet from the previous year. By the end <br />of the water year, active storage In the system <br />was approximately 105 percent at the January <br />1 maximum avaHable storage. This <br />"maximum available storage" represents <br />storage at all Bureau of Reclamation <br />(Reclamation) and Colorado River Storage <br />Project (CRSP) reservoirs, Lake Havasu and <br />above. Flood control regulations require a <br />minimum 01 5,350,000 acre-feet 01 vacant <br />space In the system 6n January 1. <br /> <br />Projected Plan of Operation <br />Under Criteria-Water Year 1984 <br /> <br /> <br />Determlnetlon 01 "602[al Storage" <br />Section 602 (a)(3) of the Colorado River Besln <br />ProJect Act of September 30, 1988 (Public Law <br />90-537). provld.s lor the slorage of Colorado <br />River water, not requIred to be released under <br />article III (c) and III (d) of the Colorado River <br />Compact In Upper Basin reservoirs, to the <br />extent the Secretary of the Interior (Secretary) <br />flndaft necessary to assure compact deliveries <br />without Impairment of annual consumptive <br />uses In the Upper Basin. <br /> <br />Article /I or the "Crlt.rla lor Coordinated <br />Long-Range OperatIon of Colorado River <br />Reservoirs" (Op.ratlng Criteria) provides that <br />the annual plan of operation shall Include a <br />determination by the Secretary of the quantity <br />of water considered necessary to be In Upper <br />Basin storage as of September 30 of the <br />current year. <br /> <br />This determination shall consider alt <br />applicable laws and relevant factors Including, <br />but not limited to the following: (a) historic <br />streamllows; (b) the most critical period 01 <br />record; (c) probabilities of water supply; (d) <br />estimated future depletions In the Upper <br />Basin, Including the effects ot recurrence of <br />critical periods of water supply; (e) the <br />"Report of the Committee on Probabilities <br />and Test Studies to the Task Force on <br />Operating Criteria forthe Colorado River," <br />daled October 30,1969, and such addltlonel <br /> <br />3 <br />