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Executive Summary operating criteria reduced the maximum peak releases and daily fluctuations, With the passage of the Grand Canyon Protection Act of 1992, the Congress required that the Glen Canyon Dam be operated to protect and restore the downstream resources of the Grand Canyon National Park and the Glen Canyon National Recreational Area. The National Environmental Policy Act of 1969 (42 U.S,C, 4321 et seq,) requires that a detailed environmental impact statement be prepared for every major federal action that may significantly affect the quality of the human environment. The act and its implementing regulations set forth the requirements for preparing an impact statement. Among other things, a statement must (1) address the purpose of and need for the action, (2) describe the environment that will be affected, (3) identify alternatives to the proposed action, (4) present the environmental impacts of the proposed action (including the direct, indirect, and cumulative impacts), and (5) identify the agency's preferred alternative, The act does not require, and Reclamation did not perform, a cost and benefit analysis of the proposed action, In preparing the environmental impact statement for the operation of the Glen Canyon Dam, Reclamation identified 11 resources affected by the dam's operations to be analyzed in detail: water, sediment, fish, vegetation, wildlife and habitat, endangered and other special-status species, cultural resources, air quality, recreation, hydropower, and non-use value, (Non-use values have been defined as those values that people may receive from the knowledge that such things as rare plants and unspoiled natural environments exist, even if people do not consume or use these goods directly.) In addition, the impact statement identified nine alternative operational scenarios to be studied in detail. These alternatives can be divided into three deSCriptive categories: Wlrestricted fluctuating flows (two alternatives, including the no-action alternative); restricted fluctuating flows (four alternatives); and steady flows (three alternatives). In the final impact statement, Reclamation recommended the Modified Low Fluctuating Flow as the preferred alternative, This alternative was developed to reduce daily flow fluctuations well below the dam's previous operating levels and to provide periodic high, steady releases of short duration; the goal of this alternative was to protect or enhance downstream resources while allowing limited flexibility for power operations. Page 4 GAOIRCED-97-12 Glen Canyon Dam's Environmental Impact Statement