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

28
Razorback Sucker
Fluctuating winter flows with icy conditions may stress overwintering adults,
and low, stable flows near historic levels are recommended.
~,
REASONABLE AND PRUDENT ALTERNATIVE .
1. Refinement of the operation of Flaming Gorge Dam so that flow and
temperature regimes of the Green River wi]1 more closely resemble
historic conditions.
Typically, to produce a natural hydrograph and temperature regime,
releases from Flaming Gorge Dam must be high in. the spring, as warm as
possible in early summer, and low and stable throughout the remainder of
the year. However, because it is not possible to duplicate the exact
flows which existed historically, the Service's recommendations are
directed toward maximizing habitat as larval endangered fish enter the
drift and to the fullest extent possible based on the biology of the
species and upon the scientific data currently available. Releases
needed to produce a natural hydrograph are discussed below in more detail
with regard to timing, magnitude, and duration. Reclamation and Western
Power will monitor releases from Flaming Gorge and flows at Jensen and on
the Yampa River to ensure compliance with this opinion.
Reclamation and Western Power will convene coordination meetings with the
Service in Aprii and October of each year to review past operations and
discuss operation for the upcoming period. These meetings also will be
used to examine research flow requests for the upcoming field seasons.
Reclamation will prepare, for Fish and Wildlife Enhancement, an annual
document detailing compliance with all elements of this reasonable and
prudent alternative and detailing releases from Flaming Gorge Dam and.
flows at the Jensen, Utah, gage and from the Yampa River. Reclamation
and Western Power will integrate these flows into their annual operating
plans to further ensure that this element of the reasonable and prudent
alternative is satisfied. The Jensen gage was chosen as a point of
measurement because the flows from Flaming Gorge Dam and the Yampa River
are attenuated at this point and endangered fish also are found at this
location.
S rin
Releases from Flaming Gorge Dam will be patterned after spring flows of
the Yampa River. Flaming Gorge releases will be gradually increased
beginning between April 1 and May 15 of each year so peak Flaming Gorge
releases will match peak runoff from the Yampa River, both in timing and
duration, and thereby approximate historic average peak flows at Jensen,
Utah. A high release from Flaming Gorge Dam must be provided annually to
obtain a target peak flow between 13,000 and 18,000 cfs at Jensen, Utah,
sustained for approximately 1 to 6 weeks beginning between May 15 and
June 1. To achieve this flow, a release of 4,000-4,700 cfs will be
required for the 1 to 6 weeks. The duration of these peak releases will