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<br />f"~\ <br />",-'';:J <br />'~':..> <br /> <br />-'"", <br />'~c:w.l <br />'<.' -'I).. <br />'''''.'''' <br /> <br />V. Ensure the longevity of sedin,ent to provide diversity of aquatic <br />habitat in the river downstream of Glen Canyon Dam by limiting the <br />frequency of flooding and restricting maximum powerplant releases. <br /> <br />A. Objective <br /> <br />1. The Bureau of Reclamation (Reclamation) will develop formalized <br />operating criteria that will reduce spilling to a frequency of less than <br />one-in-twenty years and limit powerplant releases to no more than 31,500 <br />cfs. Exception to the flow limitation will be developed to provide for <br />power emergencies and to prevent unforecasted spilling. This plan will <br />be provided for review by qualified parties as part of the Glen CanyoQ <br />Environmental Studies Phase II program to assure acceptance by the <br />scientific community. <br /> <br />0..1 <br /> <br />2. Further information will be collected during Pha!le 2 of the Glen <br />Canyon Environmental Studies to assist the Fish and Wildlife Service and <br />Reclamation in the determination and definition of flood frequency and <br />maximum releases necessary to achieve this objective. Additionally, <br />long-term monitoring may be necessary to comprehend the dynamics of the <br />fluvial system below Glen Canyon in order to predict changes in humpback <br />chub habitat with any._ degree of certainty. It is possible that certain <br />operational strategies that include high flows may be beneficial to lhe <br />humpback chub it exotic, fish competitors are disadvantaged by such <br />operations. Information from other conservation measures may help in this <br />determination. <br /> <br />~~: <br />':'. <br />" <br />-~. <br />.y <br /> <br />;;'-1 <br /> <br />" ~- <br /> <br />C/.. <br /> <br />B. <br /> <br />Discussion <br /> <br />" <br /> <br />The primary purpose of this measure is to ensure the longevity of sediment <br />in the Grand Canyon area, since it is essential to the maintenance of <br />backwater habitats utilized by the humpback chub. Additionally, these <br />areas are important to other native fish and to riparian habitats. <br />Beaches form the substrate for most of the riparian habitat in the project <br />area and are part of a yet, undefined role in the food chain of the <br />peregrine falcon. <br /> <br /> <br />C. <br /> <br />Timing and Funding <br /> <br />f~, <br />:{:.: <br />v <br />-"';';1 <br /> <br />Reclamation has initiated efforts to reduce flood freCluency. Further <br />determination of the time to complete this measure win depend on the <br />duration of Phase 2, Glen Canyon Environmental Studies. <br /> <br />Funding for this measure will be provided by Reclamation. <br /> <br />7 <br />