9631

• UCREFRP Catalog Number: 9631
• Author: U.S. Bureau of Reclamation.
• Title: Operation of Flaming Gorge Dam Draft Environmental Impact Statement Executive Summary.
• USFW Year: 2004.
• USFW - Doc Type: Salt Lake City, UT.
• Copyright Material: NO

Table S-4.-Examples of Real-Time and Other Year-Specific
Information to Be Considered in Determining Annual Patterns of Releases
From Flaming Gorge Dam for Implementation of the 2000 Flow and Temperature
Recommendations to Benefit Endangered Fishes in Downstream Reaches
of the Green River
Magnitude of
Onset of Spring Magnitude of Duration of Spring Onset of Summer- Summer-Winter
Peak Flow Spring Peak Flow Peak Flow Winter Base Flow Base Flow
Forecasted and Forecasted and Forecasted and Forecasted and Forecasted and
actual inflow to actual inflow to actual inflow to actual inflow to actual inflow to
Flaming Gorge Flaming Gorge Flaming Gorge Flaming Gorge Flaming Gorge
Reservoir Reservoir Reservoir Reservoir Reservoir
Water surface
elevation of Flaming
Gorge Reservoir
Forecasted and
actual flows in the
Yampa River
Presence of adult
razorback sucker
congregations on
spawning bars
Forecasted and
actual flow in the
Yampa River and
other large
tributaries
Desired area extent
of overbank flooding
in Reaches 2 and 3
Flow conditions and
extent of overbank
flooding in
Reaches 2 and 3 in
previous year
Forecasted and
actual flow in the
Yampa River and
other large tributaries
Desired duration of
overbank flooding in
Reaches 2 and 3
Desired base flow
magnitude
Presence of
razorback sucker
larvae in the Green
River
Forecasted and
actual flow in the
Yampa River
Initial appearance of
drifting Colorado
pikeminnow larvae in
the Yampa River
Status of endangered
fish populations
Forecasted and
actual flow in the
Yampa River
Elevation of sand
bars in nursery
areas
Initial appearance of
larval suckers in
established
reference sites in
Reach 2 (e.g., Cliff
Creek)
Existing habitat
conditions (e.g.,
condition of
razorback sucker
spawning sites in
Reach 2)
Existing habitat
conditions
Status of
endangered fish
populations
Existing habitat
conditions
Status of endangered
fish populations
Status of
endangered fish
populations
Temperature of water Temperature of
released from the water released from
dam the dam
Temperature
differences between
the Green and Yampa
Rivers at their
confluence
Temperature
differences between
the Green and
Yampa Rivers at
their confluence
Source: 2000 Flow and Temperature Recommendations, table 5.3.
In most years, it is expected that the flow magnitudes and durations achieved in Reach 2
each spring would be consistent with the flow magnitudes and durations described in the
2000 Flow and Temperature Recommendations for the hydrologic classification
established in May of each year. However, because the factors listed in table S-4 are also
considered, particularly runoff conditions in the Yampa River, there would be some years
where the peak flows that occur in Reach 2 achieve the targets for either one or two
classifications higher (wetter) or one classification lower (drier) than the actual
classification established for the Green River.
It is anticipated that in some years, when the hydrologic classification for the Green River
is average, factors listed in table S-4 could occur such that it would be possible to achieve
the targets established for either the moderately wet or wet classifications. Conversely,
S-24 S• Operation of Flaming Gorge Dam Draft EIS