6006

• UCREFRP Catalog Number: 6006
• Author: Holden, P. B. and L. W. Crist.
• Title: Documentation of Changes in the Macroinvertebrate and Fish Populations in the Green River Due to Inlet Modification of Flaming Gorge Dam
• USFW Year: 1981.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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was before closure of Flaming Gorge Dam when the river was natural.
Temperatures at Greendale, Utah, one-half mile below the dam site, and
those at the Jensen U.S.G.S. gage, 94 miles downriver, were similar
(Tables 1 and 2). Flows at Jensen were higher due to the inflow of the
Yampa River between those points (Figure 1, Tables 1 and 2).
The second period was from 1963 until 1967, when the dam was closed
and the reservoir was filling. The natural low, cold flows of winter,
and high, warm flows of spring and early summer were replaced with
fairly constant, cold, low flows year-round at Greendale (Table 1).
Daily fluctuations due to power demands replaced the unaltered, seasonal
pattern. Below the mouth of the Yampa River, temperatures were more
natural (Table 2) as the Yampa ameliorated the cold, low flows of the
Green (Vanicek, Kramer, and Franklin 1970).
The third period includes 1967 to 1978, after the reservoir was
filled, stabilized and normal operational procedures were initiated.
Temperatures of the outlet waters were slightly cooler than those of the
1963-66 years. Flows were increased considerably though, nearly double
the 1963-66 levels for most months of the year (Table 1). As a result,
temperatures below the mouth of the Yampa declined slightly in mid-
summer (Table 2) because the Yampa was less able to compensate for the
higher, colder flows of the Green.
Macroinvertebrates
The c 1 os i ng of F 1 ami ng Gorge Dam in 1962 and the res u 1 t i ng altered
temperature and flow regimes since that time have had a definite effect
on a portion of the Green River (Pearson 1967). Prior to 1962, at least