WSP11446

• File Number: 8220.112.I
• Description: Dallas Creek Participating Project
• State: CO
• Basin: Gunnison
• Water Division: 4
• Date: 10/1/1979
• Author: USDOI-BOR
• Title: Endangered Species Assessment: Dallas Creek Project Colorado
• Water Supply Pro - Doc Type: Report/Study

both species are probably a transient rather than permanent resident popula- :!

tion. Thus, the small amount of water depleted from this one mile section

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of river will probably have a negligible effect on the existing transient

populations of razorback suckers or Colorado squawfish.

As stated previously the Black Rocks area in Ruby Canyon of the Colorado

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River near the Colorado/Utah state line appears to be

habitat

for humpback chub. This area also appears to be

habitat for Colorado

squawfish (Valdez, personal communication, October 1979) as recent collections

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have included adult, juvenile and young of the year squawfish. Table 4 shows

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the pre- and post- Dallas Creek Project flows at the State line. Changes due

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to the project again appear to be negligible and will undoubtedly have little

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or no effect on these two populations.

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To date, no viable populations of bony tail chub have been located

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in the Upper Colorado River Basin. However, small isolated populations may

exist below the confluence of the Gunnison River. As noted above, the project

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The project would have a small effect on the total dissolved solid (TDS)

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flows in this area will change very little from the present flows and this

will have little or no effect on any resident bony tail chub population.

concentrations in the Gunnison and Colorado Rivers by salt loading and cone en-

tration due to water use and removal. An increase in TDS concentration of

10.7 mg/l at Grand Junction, Colorado, 4.4 mg/l at Cisco, Utah, and 2.7 mg/l

at Imperial Dam is predicted as a result of the project. All four species in

question apparently have a wide tolerance range for total dissolved solids.

For instance, the Colorado squawfish and the razorback sucker have been collected

in water ranging from 200 to 1700 mg/l while a thriving population of humpback

chubs live in the Little Colorado River where the TDS is as high as 2500 mg/l.

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