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OOQ5:~6 irrespective of inflow. Flows and storage estimates in this EA are based on releasing 39 cfs through the winter of 2002-2003. Releases of 39 cfs may be marginal in terms of providing suitable macroinvertebrate habitat, and could have some negative effects on their ability to successfully overwinter. If inflows drop significantly below 39 cfs, habitat and overwintering success would be further degraded. Threatened and Endangered Species. The 15 Mile Reach is affected more than other Colorado River reaches because it is downstream of several large diversions and upstream of the Gunnison River. Low water conditions in the 15 Mile Reach during late summer and early fall especially limit habitat. Late summer target flows established by the Service for maintaining endangered fish habitat in the 15 Mile Reach are not expected to be met under No Action. Flows in the 15 Mile Reach are expected to be 90 cfs, as compared to the dry year target flow of 810 cfs. In addition, sufficient storage exists in Ruedi to meet Reclamation's obligations for endangered fish releases of 15,825 AF in 2003. A forty-year contract between Reclamation and the CWCB provides 10,000 AF of water for the 15 Mile Reach, as mentioned previously (5,000 AF annually, and another 5,000 AF 4 out of 5 years through re- regulation). Reclamation determined that drought conditions do not allow re-regulation that would provide the second 5,000AF in 2002. (This water has been supplied every year since the agreement was executed in 1990 except this year.) Reclamation also anticipates that under No Action there is a high probability that second 5,OOOAF release would not be made in 2003. Proposed Action (HUP Releases) Sport Fisheries. As with No Action, Ruedi releases for operations and contract obligations primarily occur outside of spawning and critical early development life stages for brown and rainbow trout in the Fryingpan River (Table 3.4). The frrsttwo weeks of spawning and egg incubation for brown trout would occur before releases are expected drop to the winter minimum releases. Releases under the Proposed Action would be gradually decreased and would end before the mid-October beginning of brown trout spawning and incubation, as under No Action. Winter flows are also expected to meet minimum releases creating potential to impact brown trout incubation by limiting access to redds, limiting movement for incubation, and exposing eggs to de-watering and freezing. Smith and Hill (2000) state that flow changes greater than 25% can have anegative impact on trout fisheries. No dramatic changes in flows (changes in flow greater than 25%) are anticipated during releases associated with the Proposed Action; the alternative also includes measures to gradually decrease flows over multiple days. Fluctuations in flows 'below Ruedi under this alternative, which will be less than 50 cfs per day, would not be expected to have a negative effect on macroinvertebrates, a significant food source for trout species, as mentioned. Variations of this magnitude and less are typical for a high mountain environment, such as the Fryingpan River, where summer storm events are common, and these species are adapted to fluctuations of this nature (Roline,'200l). Under this alternative, winter flows are expected to be similar to No Action: 39 cfs or reservoir inflows, whichever is less. Releases of 39 cfs may be marginal in terms of providing suitable macroinvertebrate overwintering habitat and could have some negative effects their ability to successfully overwinter. If inflows dropped significantly below 39 cfs, habitat and overwintering success would be further degraded. Reclamation typically operates the reservoir to release 39 cfs to the Fryingpan River irrespective of inflow. Estimates in this EA are based on releasing 39 cfs to the Fryingpan River from November 1,2002 through April 30, 2003. 16