9584

• UCREFRP Catalog Number: 9584
• Author: U.S. Fish and Wildlife Service.
• Title: Draft- Aspinall Unit Operations Study.
• USFW Year: 1988.
• USFW - Doc Type: \
• Copyright Material: NO

Next, a new station was added to the network to represent the
North Fork of the Gunnison River, and a local flow table was used
to replace existing flow at the headwaters. After this
disagregation, the North Fork is set to represent all inflow
between Crystal and Grand Junction, less the Uncompahgre.
The next station modeled is the Gunnison River below the
Uncompahgre River. This station is used to simulate agricultural
diversions in the lower Gunnison and to account for a number of
small projects. These projects include small diversions
associated with the cumulative effects analysis which is required
under Section 7 of the Endangered Species Act. These annual
demands include:
KAF
Municipal and industrial use 12.4
Fish and wildlife 2.4
Minerals - lower Gunnison 6
Dallas Creek depletions 25.4
Total 46.2
The depletions from the Dominques project, which can be modeled at
this station, were been removed from the baseline at the request
of the Bureau. (Letter from Cliff Barnet).
For this discussion of the operation of the Unit, the terminus of
the Gunnison River network is the Whitewater gage, located on the
Gunnison River above Grand Junction. The Whitewater gage was used
for calibration and validation of the model before any operational
scenarios were modeled.
Discussion
Having accomplished the above disagregation, two potential
problems arose: 1) the model became less dependant on the CRSS
virgin flow and became somewhat hard-wired to gage data, and
2) the agricultural depletions which are identified in the CRSS
demand data-base file became partly included in the gage flows
being considered as inflow for the Uncompahgre and the North Fork.
The first problem becomes less of a problem when the purpose of
the modeling effort is considered. The model is to be used for
cumulative effects analysis under Section 7 and to evaluate the
reoperation of the Unit to benefit Colorado River endangered
fishes. The use of gage data tends to lend credibility to both
endeavors and only presents a problem if the model were to be used
to evaluate agricultural uses of water.
The second problem is more complicated because a considerable
amount of historic agricultural use is included in the gage flows
which are now used to represent the Uncompahgre and the North
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