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Valley. The bald eagle is an unusual but regular winter visitor that occasionally perches in large cottonwood trees along the Upper Colorado River. The interior least tern is a migrant that is occasionally observed in open water areas of the Grand Valley. The Southwestern willow flycatcher, reported to breed in the Grand Valley, inhabits the riparian zone and forages over open land habitats. Alternative 1 - No Action Floodplain and wetland habitats would remain disconnected from adjacent rivers along the Upper Colorado, Green, and Gunnison rivers. Additional floodplains and wetlands would probably be disconnected in the future. Without a connection with the river, small food organisms that are required during the critical period for endangered fish larvae would not be produced. This would hinder recovery of the endangered fishes, particularly the razorback sucker, and possibly lead to the extinction of that species. Food produced within the floodplain would also not be available to fishes within the main river channel, including the endangered fishes. The listed bird species also rely on a healthy riparian ecosystem to meet their habitat needs. Alternative 3 - Protection and Enhancement of Flooded Bottomlands by Acquisition Increased survival of razorback sucker larvae would be anticipated, resulting from increased densities and desired sizes of food organisms, inundated vegetation that provides cover from predators, and warmer water temperatures that enhance growth rates. Food produced in the floodplain would be expected to benefit all fishes in the river, including endangered fishes. Other endangered species would be expected to benefit as well. Protection of floodplain habitats including riparian wetlands and cottonwood bottomlands would provide roosting and feeding areas for the bald eagle and peregrine falcon. The Southwestern willow flycatcher and least terns may benefit over the long term when additional wetland habitats are enhanced by restoring flooding. I I I I I I I I I I I I I I I I I I I During floodability enhancement activities, listed bird species could be disturbed. Prior to any construction or levee breaching an inventory would need to be conducted to ensure that no listed species are in the area, and that occupied habitats are not impacted. D. Vegetation and Land Use The riparian vegetation in the floodplains of the Colorado, Green, and Gunnison rivers consists primarily of cottonwood, willows, tamarisk, and Russian olive. In unaltered floodplains, broadleaf cattail, some hardstem bulrush, and sedges are the dominant non-woody plants. Low vegetation of adjacent uplands consists of various grasses, forbs, and sagebrush. . Much of the Grand Valley is rural and remains primarily an agricultural area dominated by orchards, vineyards, and row crops. There are some areas that have industrial, residential, or recreational development. One of the most noticeable non-agricultural uses of the floodplain within the Grand Valley is gravel mining, which will be discussed in detail below. From Palisade to Rifle, Colorado, land use in the floodplain of the Colorado River is primarily for hay production and wintering areas for livestock. Land use in the floodplains of the Gunnison River near Delta, Colorado, and the Green River near Vernal, Utah, are similar. Levees and dikes have been constructed along much of the river within these areas to prevent flooding of agricultural and residential lands. Gravel-pit ponds are a dominant feature in the floodplain along the Colorado and Gunnison rivers. Gravel mining supplied materials for construction of Interstate Highway 70 and for commercial and residential development, and resulted in numerous III - 6