9432 ‎(2)‎

• UCREFRP Catalog Number: 9432
• Author: Modde, T. and M. Fuller.
• Title: Feasibility of Channel Catfish Reduction in the Lower Yampa River.
• USFW Year: 2002.
• USFW - Doc Type: Vernal.
• Copyright Material: NO

The end products to be derived from this evaluation included:
1. seasonal use of the passageway by native and nonnative fish,
2. a determination of the feasibility of passage for Colorado
pikeminnow,
3. information on demographics of upstream migrants following passage,
4. significance of nonnative fish control, and
5. operational guidelines for the passageway.
STUDY AREA
General
The Gunnison River, a major tributary to the upper Colorado River, arises
at the junction of the East and Taylor rivers near Almont in southwest Colorado.
It flows for about 150 miles, primarily in a west-northwesterly direction, before
it empties into the Colorado River at Grand Junction (Figure 1). The basin
derives its water supply primarily from the large snow packs that accumulate in
the high mountains during the winter. The Gunnison watershed includes the West
Elk Mountains, northern San Juan Mountains, the southern portion of the Grand
Mesa, and the eastern side of the Uncompahgre Plateau. The Gunnison River drains
about 20,534 square km (Wiltzius 1978) and contributes approximately 1.85 X 106
AF of water or about 14 percent of the total average annual runoff of the
Colorado River measured at Lees Ferry, Arizona (Cooper and Severn 1994). Between
1970 and 1999, it contributed about 40 percent of the total average annual flow
to the Colorado River at the confluence of the two rivers at Grand Junction
(personal communication, Joe Sullivan, USGS).
A majority of this 5-year evaluation was conducted at the fish trap of the
passageway at the Redlands Diversion Dam on the Gunnison River (RM 3.0).
Electrofishing was conducted in the 2.3-mile reach of the Lower Gunnison River
between the Redlands Diversion Dam and the confluence with the Colorado River (RM
3.0-0.7) to collect fish for radiotag implantation. Additional fish were
collected for radiotag implantation with trap nets and trammel nets from two
ponds connected to the river (Gardner and Pickup ponds) in the 15-mile reach and
from Walter Walker Wildlife Area (WWWA; RM 163.7) in the 18-mile reach of the
Upper Colorado River. Electrofishing was also conducted in the Gunnison River
from Delta (RM 57) to Redlands Diversion Dam (RM 3.9). Telemetry from boats was
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