8119

• UCREFRP Catalog Number: 8119
• Author: Valdez, R. A. and B. R. Cowdell.
• Title: Effects of Flow Regulation and Ice Formation on Overwinter Nursery Habitat and Survival of Age-0 Colorado Squawfish in the Green River Below Flaming Gorge Dam - Draft.
• USFW Year: 1996.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

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LIST OF FIGURES

Figure 1.
Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

General location and sampling reaches on the Green River. . . . . . . . . . . . . . . . . 3
Hourly releases from Flaming Gorge Dam (converted from megawatts to
cubic feet per second), and hourly flows of the Green River at Jensen, Utah
(USGS gage 09261000) for December through February of 1993-94 and
1994-95. (Converted from megawatts to cubic feet per second, megawatt
data courtesy of Brad Vickers, Bureau of Reclamation). ................... 8
Representative average and extreme hourly releases from Flaming Gorge
Dam for January and February, 1994 and 1995. (Converted from megawatts
to cubic feet per second, megawatt data courtesy of Brad Vickers, Bureau of

Reclamation). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Frequency of months with ice formation on the Green River from 1946 to
1992. From U.S. Geological Survey Field Notebook; Data Courtesy of J.
Schmidt, Utah State University. .................................... 12
Monthly maximum and minimum air temperatures (average of daily maxima
and minima) for the winters of 1993-94 and 1994-95, compared to average
temperatures recorded at the NOAA weather station in Jensen, UT. ........ 14
Mean daily river temperatures and minimum daily air temperatures recorded
near Jensen, UT for winters 1986-87, 1987-88, 1993-94, and 1994-95, as
well as the period of observed surface ice. Water temperatures were
recorded at the USGS gage near Jensen, UT. Minimum daily air
temperatures were recorded by the NOAA weather station at Jensen, UT. . . . . 15
Average faU and spring densities of age-O Colorado squawfish in reaches 3
and 4 of the Green River for year classes 1987 through 1995. Percentage
decrease or increase (+) in densities are indicated. ..................... 25
Flow and temperature of the Green River, based on the USGS gages at
Green River (Reach 3) and Jensen (Reach 4). Fish sampling periods are

indicated. ..................................................... 27

Key Words:
Colorado River Basin, Green River, Colorado squawfish, nursery habitat, flow regulation, ice
formation, Flaming Gorge Dam, overwinter survival.

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