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<br />Chapter II Description of Alternatives 16 <br /> <br />fish species which have been introduced to the river system. These warmwater competitors <br />are suppressed by the existing cold-water discharges from Glen Canyon Dam. Once they <br />reproduce in warm water, humpback chub do very well in cold water. The proposed action <br />would continue to control this competition by the selective discharge of warm and cold <br />water. Warm water would be released to allow the humpback chub to reproduce, the cold- <br />water releases would be used to control competitors. This management option would not be <br />possible if the dam were removed. <br /> <br />Fund other Recovery Efforts - Hatcheries or recovery of other populations of humpback <br />chub are beyond the scope of this study and do not implement the reasonable and prudent <br />alternative of the FWS's biological opinion on the operation of Glen Canyon Dam. The <br />purpose of the action alternative of this environmental assessment is to establish conditions <br />supporting the removal of jeopardy to endangered fish in the Grand Canyon. The Recovery <br />Program participants are reluctant to concentrate all their efforts above Glen Canyon Dam. <br /> <br />Reservoir Destratification - This alternative would mix the reservoir near the dam to warm <br />the water taken into the penstocks. This technique has been used in small reservoirs and <br />ponds to improve water quality, but not in large reservoirs. This alternative could be very <br />expensive and complicated by the size of the reservoir and the complex patterns of winds and <br />currents. <br /> <br />DESIGN ALTERNATIVES CONSIDERED <br /> <br />A value planning study, dated April 24, 1997, was conducted to screen various design <br />alternatives to modify the intakes of the dam to control temperatures and develop appraisal <br />level costs. Proposals 2A, 3, and 4 were recommended for more detailed (feasibility level) <br />analysis. Feasibility level costs were developed for these three design alternatives and <br />reported in a technical memorandum dated September 1997. The feasibility level costs for <br />these alternatives are included below. Proposal 2A is an innovative solution and has become <br />the action alternative. Proposals 3 and 4 are more traditional design solutions, would have <br />similar effects, but are significantly more expensive. <br /> <br />Proposal No. I - Use existing spillway structure to release warm surface water from the <br />reservoir: This proposal would use the existing spillway channels to release warm surface <br />water from the reservoir as an alternative to structural modifications to the dam. The <br />appraisal level cost of this proposal was $13,500,000 per year based on lost power revenues <br />and assumes that 8,000 ft3 Is is released through the spillway, which corresponds to two units <br />off-line for 3 months. The clear benefits of this proposal is its lack of structural changes. Its <br />disadvantages are its high annual cost and the potential for dissolved gas problems impacting <br />the downstream trout fishery. In comparing this alternative to others, its capitalized costs <br />would easily exceed $100 million. This proposal might provide a method to test the impacts <br />of warmwater releases, but the costs for even 1 year of operation are about equal to the action <br />alternative. This proposal was not brought forward for more detailed cost analysis. <br /> <br />Fifty percent of the time the water elevation would be above 3,653 feet. When the water <br />