7073

• UCREFRP Catalog Number: 7073
• Author: Brewer, M. and J. Renne.
• Title: Application of the Instream Temperature Model to the Green River Basin
• USFW Year: 1989.
• USFW - Doc Type: Draft.
• Copyright Material: NO

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Instream Temperature Model " "DRAFT" "
Page 4
March 27, 1989
Sartoris (1976) developed a mathematical water temperature model to
evaluate the effect of selective withdrawal modifications at Flaming
Gorge Dam on water temperatures in the Green River immediately
downstream.. The average monthly error between predicted and
observed mean daily river temperatures 70 kilometers downstream
ranged from 0 to -1.2°C.
STUDY METHODS
S t_u d Y... D_e s _i g_n
Changing the operation of Flaming Gorge Reservoir may change stream
temperatures in downstream areas currently inhabited by squawfish.
The Service must determine what these changes are and the subsequent
effects on squawfish populations. The instream temperature model
can be used to predict instream temperatures resulting from various
reservoir operations. Service biologists can then determine if
selected reservoir operations change instream temperatures enough to
affect squawfish habitat.
S_t, u. d..y....,. A, r_e, a
The Green River has important young-of-year squawfish habitat from
river kilometer 32 to river kilometer 145. The area between
Horseshoe Bend (river kilometer 322) to Sand Wash (river kilometer
467) on the Green River is also an important young-of-year squawfish
area. Important adult squawfish habitat is found in the lower Yampa
River and in the Green River throughout Grey Canyon and Desolation
Canyon as well as split mountain. However, adult squawfish are
dispersed throughout the Green River.
Data Collection
Daily river discharge and temperature data were obtained-from USGS
gaging stations within the network (Table 1). The period selected
for our study was 1978 to 1987. This period was selected because
Service biologists have growth rate versus water temperature data
for the squawfish for this period. Thus, water temperature predic-
tions from this study can be used to predict resultant growth rates
and early life mortality of the squawfish. A bi-weekly time period
within each year was selected starting from March and ending in
September when water temperatures are at least 13°C. These time
periods, and the associated Julian calender start and end dates, are
in Table 2.
Daily climatological data were obtained from Mr. Nolan Doesken,