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0032J8 Affected Environment and Environmental Consequences CHAPTER 3 Chapter 3 describes hydrology (water volume), aquatic life (including threatened and endangered fish), threatened and endangered wildlife, recreation, economic and social environment, hydropower production, and cultural resources of the Ruedi Reservoir area. These are the resources that could be affected by the Proposed Action. This description is followed by an analysis of the effects of the alternatives (explained in Chapter 2). Effects of the No Action Alternative are presented first, followed by effects of the Proposed Action. Scoping determined that Indian trust assets (legal interests in property and rights held in trust by the U.S. for Indian tribes or individuals), environmental justice (adverse effects to a particular social-economic group, including low-income or minority populations), wetiands, floodplains, or migratory birds wouldn't be affected by either of the alternatives in this EA. HYDROLOGY Affected Environment The primary source of streamflow in the Upper Colorado River basin above the Gunnison River is the spring melting of accumulated winter snowpack. The annual hydrographs of rivers in the area show highest streamflows occurring during the late spring and early summer. Streamflow is at its lowest during the winter. Streamflows in the Fryingpan River are stored in Ruedi Reservoir during peak runoff, and then released for users later in the year. Ruedi Dam is a major structural feature of the Fryingpan-Arkansas Project. The reservoir has an active conservation capacity of 102;373 AF at elevation 7,766.0 feet. Replacement capacity of the reservoir is used to replace water diverted out of priority from the Western to the Eastern Slope by the project; Ruedi's regulatory capacity provides for other uses on the Western Slope (Table 3.1 displays pool allocations and volumes). The Fryingpan River below Ruedi Reservoir is a cobble-boulder bed channel typical of high mountain streams in the Rocky Mountains. Geologic features ofthe Fryingpan Valley, especially steep canyon walls and erosion resistant sandstone, shape the general form of the Fryingpan River, essentially restricting lateral and vertical movement of the channel (BRW, Inc 1999; USDI, 1989). Because of these factors and the large size of the bed and bank materials that form the Fryingpan River, the channel is considered relatively stable (BRW, Inc 1999; USDI, 1989). Through most of its length to the town of . Basalt, the channel is adequate to contain approximately 1,000 cfs (USDI, 1989). The Ruedi Reservoir, Colorado, Round II Water Marketing Program Final Supplement to the Environmental Statement (USDI, 1989) characterizes the Roaring Fork River in the following manner: The Roaring Fork River below the Fryingpan confluence is a boulder- and cobble-bed channel, which is well incised into the alluvial valley deposits along most of its length. The channel has 9