WSP05745

• File Number: 8240.200.43.A.2
• Description: Grand Valley/Orchard Mesa
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1999
• Title: Evaluation of Fish Passage at the Grand Valley Irrigation Company Diversion Dam on the Colorado River Near Palisade, CO - Draft Report
• Water Supply Pro - Doc Type: Publication

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Colorado River
USGS Streamflow Gage @ Palisade

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Estimated Discharge that the GVIC
Diversion Dam Is Inundated \&

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.-- 1997 ---.. oil

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MONTH

Figure 3. Mean daily streamflow (cfs) for the Upper Colorado River near
Pal isade, Colorado, for the water year October 1997 to
December 1998. Data were obtained from the USGS gage, number
09106150, below Grand Valley Diversion, near Palisade,
Colorado.

tagged. A total of 5.72 hours were expended electrofishing downstream following
runoff (Table 1) _ During the I-year study, a total of 1.571 native and 244
nonnative fishes were either PIT tagged, floy tagged, or fin clipped (Table 1;
Appendix Table B.l.). A total of 12.83 hours of electrofishing were expended
downstream capturing fish to mark during both pre-runoff and post-runoff.

Ten days between 17 July and 21 October were spent electrofishing (8.77
hours; Table 1) upstream of the GVIC Diversion Dam in which a total of 2,338 fish
were collected (Appendix Table C.l.). Only one fish of the 1,815 fish either
marked during pre-runoff (April) or during post-runoff (July and August), was
recaptured upstream of the GVIC Diversion Dam (recapture rate=0.06%; Appendix
Table C.l.). This fish, an adult carp Floy tagged 19 August at RM 183.5, was
recaptured approximately 300 yards upstream of the diversion dam one week later
(26 August). Because there was no water spilling over the diversion dam during
this one-week period following marking, it was assumed that this fish used the
newly-constructed notch for passing by the diversion dam (Figure 3). During this

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