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OJ15j8 Chapter 3 - Affected Environment and Environmental Consequences scenic river. Similarly, no refuge exists in the affected area. However, each alternative involves actions that would take place in the Colorado River and its 100-year floodplain. Floodplain and Wetlands Protection Issue: The Colorado River provides highly valued habitat and floodplain functions that need to be considered as fish passage is restored. Existing Conditions: The surface area of the pool upstream of the dam is about an acre, and the stream bank is protected from erosion by riprap along the highway and railroad beds. The plunge pool at the base of the darn is deep, and a long riffle reach extends downstream. Deposition and transport of sediment in the river depends on variations in seasonal and annual river flows. Narrow strips dominated by willows and the introduced tamarisk occur along the river, but very little riparian vegetation is in the construction area at the Price-Stubb Darn. A small patch of shrubs and a mature cottonwood at the Price-Stubb Darn may be of importance to birds (see Fish and Wildlife section). Impacts No Action: The No Action alternative assumes a hydropower plant would still be built under the existing FERC license. Mitigation measures required to reduce wetland impacts from its construction would be identified as part of the licensee's 404 permit. Fish Ladder (with or without Hydropower Plant): A mature cottonwood tree at the site would be lost. Due to the limited space, routing a fish ladder around the cottonwood tree is not possible. Revegetation of the site would mitigate for temporary losses of other vegetation. Dam Removal: The contract for removal would require protection of the mature cottonwood tree at the dam site. Revegetation of disturbed areas would rapidly mitigate losses of vegetation. Fish and Wildlife Resources The affected area, for purposes of assessing impacts to fish and wildlife, corresponds to the 100- year floodplain of the Colorado River from the Price-Stubb Darn site upstream to Rifle. There are no significant concerns for project effects on fish and wildlife resources in general; concerns focus on avoiding adverse impacts to endangered species (U.S, Fish and Wildlife Service, 1999) as well as complementing efforts to establish self-sustaining populations of endangered Colorado River fish species. 36