WSP09978

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1994
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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weeks duration will be made respectively, Under all inflow scenarios, low stable flows
between 31.2 and 51.0 m3/s (1,100 and 1,800 cfs) will be maintained on the Green River
near the Jensen, Utah, gaging station during the summer and fall months by adjusting
Flaming Gorge releases, These operations for fishery objectives limit the powerplant
peaking and regulating capability, Flaming Gorge is expected to fill in 1994 except under
the probable minimum inflow scenario.

Water year 1994 will be the 3rd year of the 5 year study called for in the FBOFG to further
determine the flow needs of the endangeredtishuuring-the spring and winter months,

Blue Mesa, Morrow Point, and Crystal Reservoirs (Aspinall Unit)

In wllter year 1993 the April through July runoff into the Aspinall Unit was 1,218 MCM
(.987 MAF) or 136 percent of the long term average. Water year 1993 unregulated inflow is
expected to be 1,552 MCM (1.258 MAF) or 115 percent of average, With this level of
inflow approximately 527 MCM (.427 MAF) of water bypassed the powerplant at Crystal,
but no bypasses occurred at Blue Mesa or Morrow Point. Releases of up to 169.9 m3/s
(6,000 cis) occurred at Crystal with flows in the river below the tunnel in excess of 152,9
m3/s (5,400 cfs). Even with the high level of runoff (approximately the same as in 1984),
major flooding did not occur because there was adequate time to draw down Blue Mesa.
Large fluctuations in releases on a daily and hourly basis were avoided. Blue Mesa easily
filled in water year 1993.

Section 7 consultation with the Fish and Wildlife Service on the operation of the Aspinall
Unit was continued in 1993. As part of this consultation, a 5 year plan to study the effect of
various release patterns on habitat and possibly on the reproductive success and
reintroduction of endangered fish in the Gunnison River was outlined. Water year 1993 was
the second year of this 5 year study and met the goals of the high release year,

Additionally, the Aspinall Unit was operated as if the draft contract between Reclamation,
the National Park Service, and the State of Colorado to deliver water from the Aspinall Unit
to the Black Canyon of the Gunnison National Monument was in place. The operation was
also coordinated with the Fish and Wildlife Service and others interested in the operation of
the Aspinall Unit.

For water year 1994 operations, Blue Mesa Reservoir will be drawn down to at least an
elevation of 2283.0 m (7490 feet) by December 31, 1993, in order to minimize icing
problems in the Gunnison River, Blue Mesa will continue to be drawn down through April,
1994, to a level that will accommodate the most probable inflow scenario and accomplish the
release objectives with minimum powerplant bypasses at Crystal.

The minimum release objective of the unit is to meet the delivery requirements of the
Uncompahgre Valley Project and to keep a minimum of 8,5 m3/s (300 cfs) flowing through
the Black Canyon of the Gunnison National Monument. If the 8.5 m3/s (300 cfs) minimum
objective can not be maintained due to low inflow and storage conditions, the release may be

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