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Chapter II Description of Alternatives 14 the cold mainstem die of thermal shock or from predation elicited by erratic swimming behavior. For those fish old enough to survive the transition, swimming ability may be reduced by as much as 98% by cold mainstem temperatures." Warming releases in the mid to late summer timeframe would very specifically benefit native fish. The second more ambitious goal would be to remove the temperature constraint in the river during the summer months to promote new areas of spawning and recruitment. Releases would ramp up to about 15 oC over the month of June, sustain 15 oC releases through July and August, and then ramp down through the month of September. Monitoring of the resources would be conducted by the Grand Canyon Monitoring and Research Center. Then, given the test results of the monitoring program, changes in the release pattern would be considered through the Adaptive Management Process. Warmwater releases will need to be limited to 15 oC to prevent negative impacts to the tailwater trout fishery. Warmwater releases may also need to be limited in magnitude, duration, timing, and frequency to control competition from non-native fish. Fortunately, humpback chub and other native species are long-lived (20-30 years) while non-native fish tend to be short-lived (2-5 years). Ifrequired, infrequent use of temperature controls (possibly as little as once in 5 years) should greatly favor native fish that live for decades. Timing could also be adjusted to favor native fish and discourage the major competitors. Proposed Schedule for Construction - The FWS biological opinion requires Reclamation to expedite the evaluation and implementation of temperature controls iffeasible. Reclamation has scheduled its environmental compliance work and requested funding so that the project could begin construction in fiscal year 2000. The actual construction period would span between 2 to 3 years and would depend upon the rate of funding received from Congress. Annual Operation and Maintenance Costs - The Grand Canyon Monitoring and Research Center (GCMRC) estimated that a portion of the cost of a monitoring program for temperature controls is already included in their existing monitoring program. The table that follows shows the additional costs for the monitoring program which would either need to be prioritized into GCMRC's existing budget or may require additional fund. Physically, the intake modifications to the dam are relatively simple to operate and maintain. Because each gate would be operated by an individual hoist, operation would be as simple as pushing a button. Maintenance of the eight hoists, cables, and electrical equipment would be periodic and simple. If the shear pins on the relief gates need to be reset often, this may require a day-long effort on each gate. Special precautions have been designed into the relief gate shear pin mechanism which make this unlikely. The cost of the operation and maintenance was estimated by Glen Canyon Dam maintenance staff to fall well below $ I 00,000 per year. As required by the authorizing legislation, all operation and maintenance costs would be paid by revenues generated by the sale of power.