WSP09925

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1999
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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In water year 1999, Flaming Gorge will again be operated in accordance with the BOFG. A
revised biological opinion on the operation of Flaming Gorge Dam is due out in December
1998. This revised opinion will likely describe specific constraints during the spring and winter
seasons, but may also refine the constraints for the entire year.

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

In water year 1998 the April through July unregulated runoff into Blue Mesa Reservoir was
697 MCM (0.565 MAF) or_~1 percent of average, Water year 1998 unregulated inflow was
I, I 05 MCM (0.895 MAF) or 92 percent of average. Water year 1998 power plant bypasses were
approximately 133 MCM (0.1 08 MAF) at Crystal, the result of annual system maintenance ~
spring runoff exceeding powerplant capacity. Releases and spills up to 113 cms (4,000 cfs)
occurred at Crystal with flows in the river below the tunnel in excess of85 cms (3,000 cfs). Blue
Mesa filled easily during water year 1998.

Section 7 consultation with the Fish and Wildlife Service on the operation of the Aspinall Unit /
continued in 1998. As part of this consultation, a five-year effort to study the effect of various
release patterns on habitat, reproductive success, and reintroduction of endangered fish in the I '
Gunnison River is underway.

Additionally, the Aspinall Unit was operated as if the draft contract between Reclamation, the I {~
National Park Service, and the State of Colorado to deliver water from the Aspinall Unit to the I'
Black Canyon of the Gunnison National Monument were 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 1999 operations, Blue Mesa Reservoir will be drawn down to at least an elevation
of2,283 meters (7490 feet) by December 31, 1998, in order to minimize icing problems in the
Gunnison River. Blue Mesa will continue to be drawn down through April 1999 to a level that
will accommodate the current most probable inflow scenario and accomplish the release
objectives with minimal power plant bypasses at Crystal.

The minimum release objective of the Aspinall Unit is to meet the delivery requirements of the
Uncompahgre Valley Project and to keep a minimum of8.5 cms (300 cfs) flowing through the
Black Canyon of the Gunnison National Monument and to maintain a minimum of8.5 cms (300
cfs) below the diversion structure at Redlands (at the confluence of the Gunnison and Colorado
Rivers) during the summer months. Under all three inflow scenarios, Blue Mesa is expected to
fill in the summer of 1999 and flows through the Black Canyon of the Gunnison National
Monument are expected to be above the minimum release objective during the summer months.
Filling of the reservoir in water year 1999 will ensure that reasonable specific releases required I
to study the protection and improvement of habitat for endangered fish can be accommodated.
The forecasted runoff for the spring of 1999 will be closely monitored to achieve these
objectives. To protect both the blue ribbon trout fishery in the Black Canyon and recreation

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