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<br />01192 <br /> <br /> <br />CHAPTER 2.0 <br />Description of Alternatives <br /> <br />This chapter describes the No Action and Proposed Action alternatives in detail and <br />describes other alternatives eliminated from the detailed study. The No Action <br />Alternative is the Modified Low Fluctuating Flow Alternative in the FEIS (Reclamation <br />1995a) and ROD (1996). These documents should be consulted for more detailed <br />information on the Modified Low Fluctuating Flow Alternative. The Proposed Action <br />consists of two major elements: <br /> <br />1. A set of hydrological scenarios and experimental dam releases that are <br />triggered by minimum sediment inputs to the Colorado River from tributaries, <br />and <br /> <br />2. Reduction of non-native fish populations, primarily rainbow and brown trout, <br />through mechanical removal and experimental dam releases from Glen <br />Canyon Dam. <br /> <br />2.1 NO ACTION ALTERNATIVE <br /> <br />Glen Canyon Dam is currently operated using the Modified Low Fluctuating Flow <br />Alternative (table 2.1) from the 1995 FEIS (Reclamation 1995a). This alternative reduced <br />daily fluctuations and the rates of increase and decrease of releases from those prior to <br />the FEIS. The No Action alternative is not one flow, but rather includes a series of <br />powerplant constraints, habitat maintenance flows, beach-habitat building flows, and <br />elements of the reasonable and prudent alternative recommended by the Fish and <br />Wildlife Service in their biological opinion (Service 1994) and accepted by Reclamation <br />(Reclamation 1995b) and the Secretary of the Interior (ROD 1996). <br /> <br />Table 2.1-Powerplant operating constraints of the ROD. <br /> <br />Modified low fiuctuating fiow <br /> <br />8,000 between 7a.m. and 7 p.m. <br />5,000 at night <br />25.000 (exceeded during habitat <br />maintenance fiows) <br />Allowable daily fiow fiuctuations '5,000, 6,000 or <br />(cfs/24 hours) 8,000 <br />Ramp rates (cfs/hour) 4,000 up 1,500 down <br /> <br />1 In high volume release months, the allowable daily change would require higher <br />minimum releases than shown here. <br />2 Maximum releases represent normal or routine limits and may necessarily be <br />exceeded during high water years (WY) Of for hydrologic reasons. <br />3 Daily fluctuation limit of 5,000 cfs for monthly release volumes less than 600,000 <br />acre-feet; 6,000 efs for monthly release volumes of 600.000 to 800,000 acre-free; and <br />8,000 efs for monthly volumes over 800,000 acre-feet <br /> <br />Parameter <br />'Minimum releases (cis) <br /> <br />'Maximum releases (cfs) <br />