7401

• UCREFRP Catalog Number: 7401
• Author: U.S. Bureau of Reclamation.
• Title: Ruedi Reservoir, Colorado Round II Water Marketing Program, Final Supplement to the Environmental Statement, Fryingpan - Arkansas Projects, Colorado.
• USFW Year: 1989.
• USFW - Doc Type: Billings, Montana.
• Copyright Material: NO

3.29
direction, while densities of the filter-feeding caddisfly Brachvicentrus
progressively increased downstream from the dam all the way to the Colorado River
station (Appendix B, Table B.6). The increase in Brachvicentrus abundance may
be due to more fine food particles as the streams increase in size as postulated
by the River Continuum Hypothesis (Vannote et al., 1980). Except for the altered
community below the dam, the macro invertebrate communities of the Fryingpan River
are indicative of excellent water and habitat quality.
Periphyton in the Roaring Fork River consist mainly of diatoms. Forty- two
(42) taxa were identified by ERT in August 1982 (ERT, 1982a).
The macro invertebrate communities at the two sampling stations on the
Roaring Fork River were fairly similar (Appendix B, Table B.6) and indicative
of good water and habitat quality. The caddisflies Brachvicentrus and Glossosoma
were the dominant taxa at both stations. Total density and biomass of
macro invertebrates were larger at downstream locations on the Roaring Fork
River. The increases were probably due to warmer summer temperatures and greater
food supplies in the Roaring Fork River below the Fryingpan River.
Information regarding the periphyton of the Colorado River is extremely
sparse. Qualitative observations during February 1982 revealed the presence of
2 green macroalgae, Ciadoohora Qiomerata and Tetrasaora cvlindrica near Parachute
(ERT, 1982b).
Benthic macro invertebrate collections in the Colorado River just below
Glenwood Springs exhibited the highest macro invertebrate density and biomass
values of any of the river sampling stations (Appendix B, Table B.6).
Brach centrus dominated the benthic community, comprising about 50 percent of
the total numbers. The benthic community in the Colorado River was indicative
of fairly good water and habitat quality.
3.4 Wildlife Biology
Riparian vegetation serves as important wildlife habitat in the study area.
Riparian vegetation occurs along river and stream terraces, alluvial fans, and
stream banks. Riparian zones generally occur in two forms in the Ruedi study
area: (1) Mountain Riparian Formation, and (2) Shrubland Riparian Formation
(Northwest Colorado Wildlife Consortium, 1982a).
The Mountain Riparian Formation occurs from 6,000 to 9,300 feet elevation,
occurring on less than 1 percent of the total land area over a 5-county area in
northwestern Colorado. Although small in size when compared to other habitats