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higher on average than those occurring between 1990 and 2000. At the same time, the committee concludes that there is no scientific basis for operating the lake at mean minimum levels below the recent historical ones (1990– 2000), as would be allowed under the USBR proposal. Operations leading to lower lake levels would require acceptance of undocumented risk to the suckers.

For the Klamath Basin coho, the NMFS RPA involves coordination of operations as well as reduction of ramping rates for flows below the mainstem dams and increased flows in the Klamath River main stem. Coordination and reduced ramping rates are well justified. However, the committee did not find clear scientific or technical support for increased minimum flows in the Klamath River main stem. Although the proposed higher flows are intended to increase the amount of habitat in the main stem, the increase in habitat space that can occur through adjustments in water management in dry years is small and possibly insignificant. Furthermore, tributary conditions appear to be the critical factor for this population; these conditions are not affected by operations of the Klamath Project and therefore are not addressed in the RPA. Finally, and most important, water added as necessary to sustain higher flows in the main stem during dry years would need to come from reservoirs, and this water could equal or exceed the lethal temperatures for coho salmon during the warmest months. The main stem already is excessively warm. At the same time, reduction in main-stem flows, as might occur if the USBR proposal were implemented, cannot be justified. Reduction of flows in the main stem would result in habitat conditions that are not documented, and thus present an unknown risk to the population.