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

Redlands Diversion Dam (Valdez et al. 1982; Wick et al. 1985; Burdick 1995;
Anderson 1999). No wild riverine razorback sucker have been collected in the
Gunnison River since 1981 when Holden et al. (1981) caught three near Delta,
Colorado. However, the Recovery Implementation Program for Endangered Fishes of
the Upper Colorado River Basin (RIP) considers the Gunnison River to be suitable
habitat for razorback sucker and a re-introduction program to restore populations
of this species began in 1995 (Burdick 2000a). The Gunnison River has never been
considered habitat for humpback chub or bonytail. However, one humpback chub was
collected in 1993 in a deep, eddy-pool complex within a canyon-bound reach at
river mile (RM) 22, and is the only known recorded capture of a humpback chub
from the Gunnison River (Burdick 1995). The nearest known population of humpback
chub is located at Black Rocks in Ruby Canyon on the Colorado River, 38 miles
downstream from the Redlands Diversion Dam.
The Redlands Dam and associated diversion canal is located on the Gunnison
River 2.3 miles upstream from the confluence of the Colorado River near Grand
Junction, Colorado. This dam has prevented the upstream movement of all fishes
and further reduced Colorado pikeminnow numbers in the Gunnison River by
preventing movement upstream of the dam since it was constructed in 1918
(Wiltzius 1978; Valdez et al. 1982; Burdick 1995). The Redlands Diversion Dam,
privately owned and operated by the Redlands Water and Power Company, is a 3.7-m
high barrier that, prior to 1994, diverted 750 cfs of water from the Gunnison
River into a canal on the left abutment for 50 weeks each year. In 1994, an
additional 100 cfs was decreed to Redlands for hydroelectric generation. Except
for occasional, prolonged low-flow periods in the Gunnison River drainage and one
week in the spring and fall during which the canal is drained for inspection and
maintenance, an average of 750 to 850 cfs is diverted into the power canal year-
round. This flow is conveyed down-canal for irrigation water (about 80 cfs) and
hydroelectric generation (about 770 cfs). Thus, Redlands now can operate the
diversion dam to divert a maximum of 850 cfs into the canal. During the winter,
Redlands diverts about 750 cfs for hydroelectric use.
The Redlands Diversion Dam is the most downstream of two low-head
structures on the Gunnison River which, prior to 1996, precluded the passage of
endangered Colorado pikeminnow, razorback sucker, and other nonlisted native
fishes into historic habitat further upstream. The other structure is the
Hartland Diversion Dam (RM 60.0; Burdick and Pfeifer 1996) near Delta. The
Redlands Diversion Dam prevents upstream passage at all flow conditions; Hartland
is an impassible barrier at most flows. However, when Hartland is overtopped at
high flows (11,600 cfs) fish may pass directly over the dam or use the riverbanks
around the dam to move upstream (Tetra Tech, Inc. 2000).
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