9301

• UCREFRP Catalog Number: 9301
• Author: Wydoski, R. S.
• Title: Green River Fishes and Invertebrates.
• USFW Year: 1967.
• USFW - Doc Type: Logan, UT.
• Copyright Material: NO

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=Hi-gher,up on the foothills -are -found Utah Juniper. J-uniperus.osteosperm
and pinyon pine, Pinus edulis. High in the protecting cliffs of Red,
Lodore, and Whirlpool Canyons are stands of Douglas fir, Pseudotsuga
menziesii.
Plants along the stream bank include rushes, Juncus; spike rushes,
Eleocharis; common reed, Phragmites communis; cheat grass, Bromus tector-
um• bee flowers Cleom& -s _• willows Salix s tamarisk Tamarix
pentadrai chokecherry, Prunus spp.; Fremont -pppl:ar;, Populus fremontii;
narrowleaf cottonwood, Populus angustifolia; and box elder, Acer neg-
undo:==The vegetation of the area has-been described by Holmgren (1962a,
1962b) and Dibble, ed. (1960).
Mean annual precipitation in the area varies from about 8 inches at
Jensen, Utah, YO'inches at°Flaming-Gorge, Summer showers are usually
of short duration but of high local intensity. These intense showers
falling on looseLs6ils with relatively sparse covers of vegetation often
cau"se flash floods --through -inormally dry washes.. When -this 'happens, the
turbidity of the Green River increases rapidly and dramatic color changes
often occur.
The average annual air temperatures at Flaming Gorge and Jensen re-
spectively are 44.3°F. and 45.5°F. Summer daytime temperatures often
reach 105°F., and nighttime air temperatures may drop to 40-5 0°F.
Winter temperatures` occasionally fall-to -30°F with -10° to X15°F. reach-
ed during most winters.
Sampling Stations
In 1964 four stations (42.7 MBD, 65.8 MBD, 78.0 MBD, and 166.0 MBD)
were sampled intensively (Table 1, Figure 1). Preliminary analysis of