9305

• UCREFRP Catalog Number: 9305
• Author: U.S. Fish and Wildlife Service.
• Title: Final Biological Opinion for the Operation of Flaming Gorge Dam.
• USFW Year: 1992.
• USFW - Doc Type: Denver, CO.
• Copyright Material: NO

23
ENVIRONMENTAL BASELINE
The environmental baseline includes the past and present impacts of all
Federal, State, or private actions and other human activities in the action
area; the anticipated impacts of a]1 proposed Federal pr•~;jects in the action
area that have already undergone formal or early Section 7 consultation; and
the impact of State or private actions which are contemporaneous with the
consultation in process.
Past Federal, State, and private actions which resulted in depletions in the
Green River are presented in Table 1 and Appendix A. To place this
information in perspective, the total potential (water already allocated
although not all may be used in any given year) depletions accumulate to
approximately 1,572,552 acre-feet annually, at or above Green River, Utah.
Comparing this to the Green River flow at Green River, Utah, which averaged
around 4,648,000 acre-feet over the past century, the depletions (real and
potential) represent approximately 32 percent of the flow of the Green River.
The total depletion for the entire Green River system is approximately
1,583,960 acre-feet.
The 32-percent depletion of the Green River affects endangered fish in two
ways. First, any depletion above Flaming Gorge Dam decreases the amount of
water which can be regulated for endangered fish (i.e., historic spring peaks
may not be attainable) Secondly, any depletion below Flaming Gorge Dam is a
net loss of water available for endangered fish. Other impacts of Flaming
Gorge Dam and current operation inc]ude changes in the temperature regime;
tfie magnitude, timing, and duration of the spring peak; and the amount of
daily fluctuation occurring in the Green River. Late spring and summer
temperatures in the Green River were moderated as a result of rel-eases from
the reservoir. Summer-winter flows were generally higher than those observed
historically. With the exception of very wet years, the magnitude of the
spring peak seldom approaches historic levels.
Table 1. Summary of water depletions in the Green River Basin.
RIVER/AREA
Green River above
Upper Green River
Yampa River
Little Snake River
Duchesne River
White River
Lower Green River
San Rafael River
Flaming Gorge
i n ~~Utah
DEPLETION (Acre-feed
372,331
145,089
129,841
48,800
542,118
131,456
125,325
89,000
TOTAL
1,583,960