9457

• UCREFRP Catalog Number: 9457
• Author: Ptacek, J. A., D. E. Rees and W. J. Miller.
• Title: A Study of the Ecological Processes on the Fryingpan and Roaring Fork Rivers Related to Operation of Ruedi Reservoir.
• USFW Year: 2003.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

INTRODUCTION
During the mid-1900's the U.S. Bureau of Reclamation built numerous dams and
reservoirs across the western United States. These dams and reservoirs were built to
control floods, provide water for agricultural irrigation, and supply growing
municipalities with needed water resources.
Dams affect rivers by regulating streamflows (Bain et al. 1988; Munn and Brusven 1991;
McKinney et al. 2001), altering the thermal regime (Hauer and Stanford 1982; Voelz and
Ward 1989; Vinson 2001) and reducing sediment input (Andrews 1986). Changes to the
physical environment caused by dams have profound impacts on the aquatic biota
downstream. Macroinvertebrate densities and community structure are often
significantly altered (Munn and Brusven 1991, Moog 1993). Salmonid populations may
significantly increase due to effects of dam operations (McKinney et al. 2001). Trout
communities in the Blue River below Dillon Reservoir, Fryingpan River below Ruedi
Reservoir, Green River below Flaming Gorge Reservoir, San Juan River below Navajo
Reservoir, South Platte River below Cheesman Dam, and Taylor River below Taylor
Park Reservoir are examples of western salmonid populations which are affected by the
altered environment created by dam construction.
Ruedi Dam was completed in 1968 (U.S. Bureau of Reclamation 1975), inundating a
portion of the Fryingpan River and creating Ruedi Reservoir, which is a large (102,373 of
[Finnell 1972]) federally owned, Fryingpan-Arkansas Project storage reservoir. Since
1968, the salmonid fishery in the Fryingpan River and to a lesser extent the Roaring Fork
River has been affected by operation of Ruedi Dam.
The Fryingpan River has developed into a world class fishery in part due to the altered
physical environment, and special angling regulations that began in 1978 (Nehring and
Anderson 1984). The introduction of the non-native opossum shrimp (Mysis relicta) into
Ruedi Reservoir provided a tremendous supplemental prey source for trout populations
below the dam (Nehring 1991).
Draft Final Report, Fryingpan and Roaring Fork Rivers February 12, 2003
Miller Ecological Consultants, Inc. Page 1