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<br />A late 1970's program to increase peaking power at Glen Canyon Dam was terminated in 1980, <br />but uprating and rewinding of the hydroelectric generators was determined to be feasible by <br />Reclamation. The Service on April 2, 1982, while concurring with Reclamation's biological <br />assessment that the incremental increase in uprated operations did not further increase jeopardy, <br />restated that the 1978 jeopardy opinion was still in effect. <br /> <br />Concern for degradation of the ecosystem downstream from Glen Canyon Dam resulted in the <br />formation of the. GCES program in December 1982, and the agreement not to use the uprated <br />capacity of the powerplant until studies and appropriate National Environmental Policy Act <br />(NEPA) compliance was completed (U.S. Bureau of Reclamation 1982). In 1987, Reclamation <br />requested consultation on the existing operation of Glen Canyon Dam which resulted in a draft <br />jeopardy opinion on August 25, 1987. In 1988, the Department of the Interior directed further <br />studies (GCES Phase ll) on low fluctuating flows, and Reclamation, Arizona Game and Fish <br />Depaitment, National Park Service, Navajo Nation Natural Heritage Program, and Service <br />developed seven conservation measures that would support the sucCessful completion of both <br />Section 7 consultation and NEPA compliance (U.S. Fish and Wildlife Service 19908). <br /> <br />t~i <br /> <br />The preparation of an BIS on operations of Glen Canyon Dam was announced July 27, 1989, <br />by the Secretary of the Interior (Secretary), arid the cooperating agencies formed an BIS Team <br />with Reclamation as lead. The Service has participated as a cooperating agency and is on the <br />BIS Team. In 1992, the Grand Canyon Protection Act (P,L. 102-575, Title XVIII) was passed <br />directing the Secretary of the Interior to develop alternatives...,. in such a manner as to protect, <br />mitigate adverse impacts to, and improve values for which Grand Canyon National Park and <br />Glen Canyon National Recreation Area were established ...,.. <br /> <br />f <br />,~.. . <br /> <br />With guidance from other cooperating agencies, Reclamation selected the Low Fluctuating Flow <br />Alternative (described in the January 8, 1993, Preliminary Draft BIS) as the preferred alternative <br />for the Draft EIS with the added component of habitat maintenance flows. With the added <br />flows, the alternative is now the MLFF. On August 12, 1993, the Service received the <br />Advanced Draft BIS which includes new and more complete descriptions of the proposed action. <br />To the extent possible, the Service has incorporated the new material in this draft biological <br />opinion, However, time did not allow a comprehensive review of the Advanced Draft EIS, and <br />changes to the action may still occur before the Draft BIS is released. <br /> <br /> <br />:,' <br /> <br />OPERATIONS <br /> <br />~~ <br /> <br />From 1963 to 1980, Glen Canyon Dam was operated under the filling criteria. These criteria <br />ended when the dam spilled for the first time in 1980, Since 1980, the objective has been to <br />produce the greatest amount of firm capacity and energy practicable while adhering to the <br />releases required under legislative mandates. Minimum allowable flows were 1,000 cubic feet <br />per second (cfs) from Labor Day until Easter and 3,000 cfs from Easter until Labor Day. <br />Maximum allowable flow was 31,500 cfs. No restrictions existed on daily fluctuations and ramp <br />'rates. Historically, daily fluctuations exceeded 12,000 cfs more than 58% of the days, and <br />20,000 cfs 15 % of the days. Provisions also were established for system emergencies and <br />system regulation. <br /> <br />13 October 1993 Dralt biological opinion 2-21-93-P'167 <br /> <br />4 <br />