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<br /> <br /> <br />Glen Canyon Dam and Power i <br />Plant <br /> <br />Glen Canyon Dam and power plant <br />is located on the Colorado River in <br />northern Arizona. It is operated by <br />Reclamation to meet Lower Colorado <br />River Basin water storage and delivery, <br />requirements, These are codified in a <br />variety of docuements known collectiv~ly <br />as the Law of the River. As the largest <br />SLCMP generating resource, Glen <br />Canyon Dam represents about two-thirds <br />of the total SLCMP capacity and thr~e <br />quarters of the energy. <br /> <br />ItlttheJ}ast; Glen Ganyon'Dam~as <br />used ]1rhnarily to generate peiikingpo~er. <br />While this operational choice made the <br />power generated at Glen Canyon mOre <br />flexible, and therefore more valuable, it <br />also caused significant hourly and daiL~ <br />fluctuations in water releases. These, <br />fluctuations caused concern because bf <br />their potential effects on the downstr~am <br />environment. In December 1982, RFcla- <br />mation began Phase I of the Glen Canyon <br />Environmental Studies (GCES) to respond <br />to the concerns of environmental anq <br />recreational interests regarding Glen i <br />Canyon Dam operations. In June 1 ~88, <br />Phase II of the GCES was initiated to <br />aqdress economic impacts to power <br />customers, along with other concerns. <br /> <br />In July 1989, the Secretary offbe <br />Interior announceq that Reclamatio~ <br />would prepare an Environmental Impact <br />Statement (EIS) on the effects of C\len ' <br />Canyon Dam operations on the do~- <br />stream environment. The EIS record of <br />decision was signed by the Secretary of <br />the Interior on October 9, 1996.. the <br />Interior Department's qecision on t/1e Glen <br />! <br /> <br />, <br />, <br />'" Operation of Glen Canyon Dam, Fin~l RIS, <br />U.S. Department of the Interior, Bureau o~ <br />Reclamation, FES95-8, dated March 21,1995, <br />Record of Decision, dated October 9, 1996. <br /> <br />Canyon Dam EIS called for restricteq <br />water releases to protect downstream <br />resources, changing the long-ternl operat- <br />ing criteria by reducing hourly and daily <br />fluctuations in water releases. This <br />affected the magnitude and timing of <br />electric power available under a range of <br />possible water conditions. <br /> <br /> <br />The decision also included general <br />provisions which would allow Western to <br />respond to power system emergencies by <br />temporarily deviating from normally <br />constrained powerplant operations, <br />Following the record of decision, the <br />Operating Criteria and 1997 Annual Plan <br />of Operations for Glen Canyon Dam, <br />approved by Secretary Bruce Babbitt on <br />February 24, 1997, included similar <br />provision for emergencies to address <br />system emergencies and load-following <br />conditions . <br /> <br />The degree to which Western can <br />use hydroelectric generation to respond to <br />power system emergencies and to satisfy <br />load-following obligations is an important <br />consideration in the Replacement Re- <br />sources Process. With this ability, capac- <br />ity from Glen Canyon Dam can be used to <br />serve load under limited emergency <br />situations, thereby allowing Western to <br />claim a higher available short-tenn onpeak <br />capacity at Glen Canyon, Replacement <br />power can then be obtained at lower cost <br />on the bulk power market than would be <br />the case in the absence of these emer- <br />gency and system regulation procedures. <br /> <br />Other SLCA Integrated Projects <br />Resources <br /> <br />In addition to Glen Canyon Dam, <br />operations at several other SLCMP <br />facilities also have been modified or will <br />be modified in the near future to address <br />environmental concerns. These facilities <br />include the Flaming Gorge Dam and <br /> <br />