2010-11-22_REVISION - M2009023 (7)

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The dam will be an earth embankment or roller compacted concrete dam and it will be constructed from on-site materials. The dam will be approximately 115 feet high with a crest elevation of 6,320 feet. The outlet works would be tunneled in either the right or left abutment of the dam. An integrated, multi-level outlet works will be installed to provide a temperature profile comparable to natural existing conditions. Conservation Measures Conservation measures are actions that the action agency and applicant agree to implement to further the recovery of the species under review. The beneficial effects of conservation measures were taken into consideration for determining both jeopardy and incidental take analyses. The Corps agrees to incorporate the following conservation measure as a condition of any issued permit. Long Hollow Reservoir will have a fish screen on the outlet works to prevent escapement of nonnative fishes. There are no plans to stock the proposed reservoir with fish. However, most reservoirs in Colorado establish fish communities regardless of whether fish are intentionally stocked by the project proponent or the Colorado Division of Wildlife" It is expected that nonnative fishes could establish in the proposed Long Hollow Reservoir and there is the potential for nonnative fishes to escape the reservoir via the outlet works or spillway. Escaped fishes could travel down the La Plata River into the San Juan River where they could prey upon and compete with native and endangered fishes in the San Juan River. With the conservation measure in place, contribution of nonnative warmwater fishes from Long Hollow Reservoir to the San Juan River is expected to be minimal. STATUS OF THE SPECIES AND CRITICAL HABITAT Colorado Pikeminnow Species/Critical Habitat Description The Colorado pikeminnow is the largest cyprinid fish (minnow family) native to North America and it evolved as the main predator in the Colorado River system. It is an elongated pike-like fish that during predevelopment times may have grown as large as 1.8 meters (6 feet) in length and weighed nearly 45 kilograms (100 pounds) (Behnke and Benson 1983). Today, fish rarely exceed one meter (approximately 3 feet) in length or weigh more than 8 kilograms (18 pounds); such fish are estimated to be 45-55 years old (Osmundson et al. 1997). The mouth of this species is large and nearly horizontal with long slender pharyngeal teeth (located in the throat), adapted for grasping and holding prey. The diet of Colorado pikeminnow longer than 80 to 100 mm (3 or 4 inches) consists almost entirely of other fishes (Vanicek and Kramer 1969). Males become sexually mature earlier and at a smaller size than do females, though all are mature by about age 7 and 500 mm (20 inches) in length (Vanicek and Kramer 1969, geethaler 1978, Harriman 1981). Adults are strongly countershaded with a dark, olive back, and a white belly. Young are silvery and usually have a dark, wedge-shaped spot at the base of the caudal fin. Critical habitat is defined as the areas that provide physical or biological features that are essential for the recovery of the species. Critical habitat was designated in 1994 within the 4