2.) As discussed with the staff of the Majority and Ranking Minority members of the Senate and House committees having jurisdiction over these matters, to fulfill the requirements of the act, we examined • whether Reclamation’s determination of the impact of various flow alternatives on selected resources was reasonable and • what, if any, concerns still exist on the part of key interested parties about the final EIS. Therefore, we believe that these limitations are not significant enough to render the final impact statement unusable to the Secretary of the Interior as a decision-making document. To address these uncertainties, Reclamation intends to initiate a process of “adaptive management” that would provide for long-term monitoring and research to measure the actual effects of the selected alternative. We did note, however, some shortcomings in the economic assumptions used in the hydropower analysis and in Reclamation’s implementation of certain methodologies. These shortcomings, combined with the inherent uncertainty in making economic forecasts, reduce the precision of the estimated economic impacts. Some of the data used in making the impact determinations were dated, preliminary, or incomplete. Reclamation recognizes that uncertainties still exist about the impact of the various flow alternatives on resources. However, while expressing their support, some organizations still had concerns about the final EIS. Several Concerns Remain About the Implementation of the Dam’s New Operating Procedures

While respondents to our survey were generally positive about the selection of a preferred alternative and the process used by Reclamation to develop the EIS, some were still concerned about the preferred alternative and the Glen Canyon Dam’s final environmental impact statement. These concerns focus on the manner in which compliance with the Endangered Species Act will be achieved, the economic impact of reducing the Glen Canyon Dam’s hydroelectric power capacity, the lack of consideration in the EIS of other causes of downstream adverse impacts other than water releases from Glen Canyon Dam, the simultaneous changing of two of the dam’s operating parameters very late in the EIS process, the adequacy of the flood frequency reduction measures, the need for selective withdrawal structures, and issues related to adaptive management, including future research and monitoring.
Why GAO Did This Study

Pursuant to a legislative requirement, GAO evaluated the Bureau of Reclamation's final environmental impact statement (EIS) on the operations of the Glen Canyon Dam, focusing on: (1) whether the Bureau's determination of the impact of various operating alternatives on selected resources was reasonable; and (2) key interested parties' concerns about the final impact statement.

What GAO Found

GAO found that: (1) in general, Reclamation used appropriate methodologies and the best available information in determining the potential impact of the dam's various flow alternatives on selected resources; (2) GAO identified some shortcomings and controversy in Reclamation's application of certain methodologies, and some of the data Reclamation used in making its impact determinations were dated, preliminary, or incomplete; (3) these limitations, combined with the inherent uncertainty associated with making forecasts, reduce the precision of the impacts in the statements, and some uncertainty remains; (4) according to GAO's analysis and the opinions of experts, these limitations are not significant enough to alter the relative ranking of the flow alternatives or render the final EIS unusable as a decisionmaking document; and (5) Reclamation recognizes that uncertainties still exist and intends to initiate a process of adaptive management that would provide for long-term monitoring and research to measure the actual effects of the selected alternative. GAO also found that, many of the key interested parties affected by the Glen Canyon Dam's EIS support the process used by Reclamation to develop the EIS as well as the implementation of the preferred alternative; however, while expressing their support, some interested parties raised specific concerns that still exist about the final EIS, including: (1) achieving compliance with the Endangered Species Act; (2) the economic impact of reducing the dam's hydroelectric power capacity; (3) the consideration of other possible causes of adverse downstream impacts; (4) the difficulties in measuring the impact of changes in the dam's operations; (5) the adequacy of measures for reducing the frequency of unscheduled floods; (6) the need for installing multilevel water intake structures on the dam to raise the downstream water temperature; and (7) the implementation of the adaptive management program.