9569

• UCREFRP Catalog Number: 9569
• Author: Valdez, R. A.
• Title: Synthesis of Winter Investigations of Endangered Fish in the Green River Below Flaming Gorge Dam.
• USFW Year: 1994.
• USFW - Doc Type: 18-11,
• Copyright Material: NO

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distance traveled by frazil ice and ice chunks beneath the surface ice. Ice profiles revealed

about 0.5 m of surface ice with accumulations of frazil ice ranging from 0.3 to 3 m thick.

Yarona River

Hvdrolo~

Average monthly flows of the Yampa River were higher in Winter 1 than in Winter

2 (Figure 10), although volume was higher in water year 1988 (October 1, 1987 - September

30, 1988). Total volume was 814,500 acre-feet in water year 1987, and 912,300 acre-feet in

water year 1988 (USGS 1987, 1988). For water year 1987 (October 1, 1986 - September 30,

1987), mean, maximum, and minimum daily discharges near Maybell were 1,125; 5,970, and

124 cfs (32, 169, and 3.5 cms), respectively. For water year 1988 (October 1, 1987 -

September 30, 1988), mean, maximum, and minimum daily discharges were 1,257; 9,800; and

37 cfs (36, 278, and 1.0 ems), respectively.

Mean monthly discharges for October, 1986 through March, 1987 were higher than

historic means (1917-1988), while mean monthly discharges for October, 1987 through

March, 1988 were lower than historic means (Figure 11).

Wick and Hawkins (1989) used regression analysis to determine the relationship

between river stage and discharge at RM 81.1 of the Yampa River. Two data sets were

compared; one from the coldest portion of the winter--mid-December to mid-February--and

the second from the warmer, high-discharge period of early March. Both data sets showed

a stage change of about 0.2 feet (6 em) for every 20 cfs (0.6 cms) reduction in discharge.

This relationship predicted that discharge reduced from lowest measured flow of 142 cfs to
e75 cfs (4.0 cms to 2.1 cms) would result in a stage reduction of about 0.7 feet (21.3 cm).