7152

• UCREFRP Catalog Number: 7152
• Author: Holden, P. B.
• Title: Relationship between Flows in the Yampa River and Success of Rare Fish Populations in the Green River System.
• USFW Year: 1980.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

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Table 6. Number of days above 600 F or 150 C at the Jensen gauge
by June 30 of each year.

Days above Days above
Year 600 F Year 150 C
1962 27 1975 13
1963 46 1976 26
1964 28 1977 35
1965 17 1978 50
1966 33 1979 63

level. Temperature patterns were slightly altered in 1977, but the

reason for this abnormality was reduced Yampa River flows.
The data presented above show that Colorado squawfish require

natural flow in order to reproduce effectively.

It appears

that the pattern of flow, i.e., a spring peak, is important, as is

the actual quantity of flow. Temperature can affect successful re-
production, especially if spawning temperatures are not met, and this

effect can override the flow requirement. Regulation of the flow of
the Yampa River would undoubtedly have serious consequences on Colorado
squawfish reproductive capabilities. Regulated flows may be lower than
those required by squawfish for successful reproduction. Temperatures
of lower flows would be more subject to variation caused by ambient
conditions. The combination of regulated flows in both the Green and