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Alternatives Considered but Eliminated from Detailed Study After careful review and consideration by the EIS team, the following alternatives and concepts were considered but eliminated from further evaluation, Remove Glen Canyon Dam - This concept is outside the scope of dam operations and the purpose of the EIS and violates congressional authorizations and the "Law of the River." Run-of-the-River Alternative - This alternative attempted to replicate Colorado River conditions similar to those existing before Glen Canyon Dam and to identify operational and structural mechanisms used to attain these conditions. Analyses indicated that this operation would create significant impacts on downstream resources and in some years fail to meet downstream release requirements. A return to seasonal streamflow patterns emulating the magnitude of historic spring flows would be very destructive to resources dependent on sediment unless a large-scale, long-term sediment augmentation program, such as a slurry pipeline, was implemented. Sediment augmentation has the potential to cause adverse impacts on the aquatic ecosystem below Lees Ferry; and high and low flows would impact resources above Lees Ferry. Such a program also would be expensive in terms of environmental damage, construction, and operation costs. Historic Pattern Alternative - Sediment erosion issues make this alternative impractical without sediment augmentation. Without sediment augmentation, the sediment resources along the Colorado River would be subject to greater erosion under this alternative than under any of the steady or fluctuating flow alternatives, including the No Action Alternative, Maximum Fluctuating Flow Alternative - The objective of this alternative was to change operations to fully utilize powerplant generating capacity (releases of 33,200 cis). This alternative attempted to define water releases to maximize the power generating capacity of Glen Canyon Dam and include a reregulation dam that would provide protection to downstream resources. Analyses indicated that while most downstream resources woul.d experience improved conditions, resources in the 16-miIe Lees Ferry reach would experience increased frequency and magnitude of daily river fluctuations. This would have negative effects on beaches and other sediment deposits, riparian vegetation and associated terrestrial wildlife, trout fishery, Native American cultural areas, archaeological sites, and the aquatic food chain. The projected impacts on resources, combined with the constraints of Section 404 of the Oean Water Act and the lengthy and difficult process to implement this alternative, render this alternative unacceptable. Move Hydropower Peaking from Glen Canyon Dam to Hoover Dam - Both Glen Canyon Dam and Hoover Dam powerplants are operated as hydroelectric peaking powerplants. There appears to be no excess capacity or energy available at the Hoover Dam powerplant to substitute for reduced peaking at Glen Canyon Dam. All of the capacity and energy at Hoover Dam is allocated by existing contracts. It has been suggested that more units could be added to the Hoover Dam powerplant to increase capacity and supply the peaking that now occurs at Glen Canyon, but the necessary additional water in Lake Mead would not be available to fully satisfy peaking requirements if additional units were installed at Hoover Dam. Therefore, power produced at Hoover Dam would not be available for use in the area served by the Glen Canyon Dam powerplant. It may be possible in the future to apply additional computer technology on a regional (or system) basis to refine and enhance the network efficiency of various hydroelectric powerplants, including Glen Canyon and Hoover. However, institutional concerns, prolonged negotiations, and other necessary arrangements would be very complex and would likely extend well beyond the scope and timeframe covered by the Glen Canyon Dam EIS. 9