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i! O'~ 7 1 7 VOl. 'U Revised Supplemental Draft Environmental Assessment-Chapter 3-Affected Environment and Environmental Consequences Conventionai Fish Ladder: The ladder would be similar to the Redlands fish ladder constructed in June 1996. Since its completion, 47 Colorado pikeminnow, 5 razorback sucker and about 36,400 native fish have passed through theRedlands fish ladder (Burdick, 2002). Installation of a fish trap to allow se~ective passage would' prevent upstream access by nonnative fish. A fish trap at this location has some advantages, however, a fish trap was included in the construction ofthe Grand Valley Project Diversion Dam fish passage about 5 miles upstream. Downstream Rock Fish Passage: Concerns for ease of fish use would be similar to those of building a conventional fish ladder. However, the passage would be more natural than the conventional type. Filling the scour hole with riprap material below the Price-Stubb Diversion Dam would likely eliminate its use by Colorado pikeminnow. However, restored fish passage at the Price-Stubb Diversion Dam and Grand Valley Project Diversion Dam would provide endangered fish access to about 50 miles of critical habitat. Reclamation formally consulted with the Service (Service, 2003) regarding the downstream rock fish passage. and an incidental take statement was issued under the Colorado Programmatic Biological Opinion for potential incidental take associated with nonnative fish and the loss of the scour hole below the dam. The Service concluded that the downstream rock fish passage alternative would be beneficial to the endangered fishes and that selective passage would be constructed at the Grand Valley Project Diversion Dam upstream. A copy of the Biological Opinion from this consultation is included in the appendices. Downstream Rock Fish Passage with Whitewater Recreation Features: Effects under this alternative would be similar to the Downstream Rock Fish Passage alternative. Whitewater features would likely draw additional public attention to the fish passage, which could provide opportunities to educate the public about endangered fish needs and the Recovery Program goals. Additional consultation with the Service regarding this alternative may be necessary to comply with Section 7 of the Endangered Species Act. If the biological opinion is revised, consultation results would be incorporated into the Final EA. Dam Removal: Removing the man-made barrier and letting the river channel return to a natural condition would be the most beneficial passage alternative for the endangered fish. If the option to modify the river channel upstream of the dam to maintain the water surface elevation at the Ute Water pump plant is pursued (see page 19), designs for the structure would be reviewed by the Service to ensure that it would not create new fish passage problems. Dam removal would also require the filling of the scour hole below the dam with rip rap material. Selective passage is being constructed at the Grand Valley Project Diversion Dam, which is the last remaining barrier to upstream movement. Nonnative fish would thus be prevented from moving further upstream into the critical habitat extending to Rifle, Colorado. However, fish passage at Price-Stubb would allow nonnative fish to access 48