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Description of Alternatives STEADY FLOWS The steady flow alternatives were designed to provide a range of downstream resource protection measures by minimizing daily release fluctuations. Flows would be steady on either a monthly, seasonal, or year-round basis. The monthly distribution of release volumes would differ, but daily and hourly operating criteria would be the same for all steady flow alternatives. Flows would be the same each day within the month or season (except during flood control operations). The scheduled annual release volume would be determined in accordance with the Long-Range Operating Criteria. Monthly or seasonal release volumes would be based on the month-to- month pattern specified for the alternative. Although the goal would be to maintain steady (uniform) water releases for selected durations, the ability to maintain a steady flow from one period to the next would depend on the accuracy of streamflow forecasts and the space available in Lake Powell. Minimum or maximum flow rates would be determined by the monthly water volume to be released. The goal would be to hold flows steady to within plus or minus 1,000 cfs per day and adjust them between months in response to forecast changes. Ramp rates within this flow range would not be restricted because river stage fluctuations would be within a few inches. The maximum change in releases between months would be 2,000 cfs per day. Daily variations of plus or minus 1,000 cfs per day (approximately 42 megawatts) would allow some minor flexibility in dam operations, primarily for electrical system regulation. AGC would cause minor fluctuations as the powerplant's computerized regulation system made adjustments every 2 to 6 seconds. Resulting changes in river stage would not be noticeable downstream. Flow fluctuations of this magnitude were measured during steady research flows, and the corresponding river stage fluctuations were small. Glen Canyon Powerplant likely would not be relied on for extended periods of AGC if a steady flow alternative is implemented. Water releases in excess of powerplant capacity would flow through the outlet works and/or spillways during high water years or, as necessary, during beach/habitat-building flows. The habitat maintenance flows included in the Seasonally Adjusted Steady Flow Alternative were not included in the other steady flow alternatives. Such flows would be contrary to the concepts for which these steady flow alternatives were developed; i.e., to keep flows steady under 28 Glen Canyon Dam EIS Summary