WSP06774

• File Number: 8282.600.10
• Description: Colorado River Annual Operating Plan
• Basin: Colorado Mainstem
• Date: 12/14/1999
• Author: USDOI/BOR
• Title: 29th Annual Report and 2000 Annual Operating Plan for Colorado River System Reservoirs
• Water Supply Pro - Doc Type: Publication

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(12,610 cfs) on June 24,1999. Releases of223 cubic meters per second (7,865 cfs) were made
during much of June. No flooding oceurred in the city of Green River, Wyoming, located 60
river miles below the dam. The flood stage is exceeded when flows at Green River exeeed 354
cubic meters per second (12,500 cfs), F ontenelle Reservoir essentially filled in July of1999 when
the elevation of the reservoir came within 0.67 meters (2.2 feet) of reaehing the crest of the
spillway.

Because the mean annual inflow oft,S 16 MCM (1.229 MAF) far exeeeds Fontenelle's storage
capacity of 426 MCM (.345 MAF), significant power plant bypasses are expected under the most
probable and maximum probable inflow scenarios. Additionally, there is little chance that the
reservoir will not fill during water year 2000. In order to minimize spring high releases, and to
maximize downstream resources and power production, the reservoir will probably be drawn
down to minimum pool elevation, 1970.0 meters (6463 feet) which eorresponds to a volume of
115 MCM (0.093 MAF) oflive storage.

Flaming Gorge Reservoir

Inflow into Flanting Gorge was above average during water year 1999. April through July
unregulated inflow was 2,103 MCM (1.705 MAF) or 143 percent of normal. High inflows,
coupled with the carryover storage from water year 1998, required releases in exeess of
powerplant capacity to be made from Flaming Gorge in water year 1999. Releases reached 297
cubic meters per second (10,500 efs) in mid June. Releases at this tinte were being made through
the powerplant, the river bypass tubes, and the spillway. This marked the first time all three of
these release capabilities have been used together since 1983. A total of300 MCM (0.243 MAF)
was released in excess of powerplant eapacity in water year 1999.

In May of 1999, a final draft report entitled "Flow Recommendations for Endangered Fishes in
the Green River Downstream of Flaming Gorge Dam" (Flaming Gorge Flow Recommendations)
was submitted to the Upper Colorado River Reeovery Program Management Committee. The
report, prepared by a multi-diseiplinary team, synthesizes research conducted on endangered fish
in the Green River under the Upper Colorado River Recovery Program and also presents flow
recommendations for three reaches of the Green River. It is expected that the Flaming Gorge
Flow Reeommendations report will be finalized by the Upper Colorado River Recovery Program
in the spring of 2000. Reclamation intends to initiate a National Environmental Policy Act
(NEP A) process on the intplementation of an operation plan at Flaming Gorge Dam that meets
these flow recommendations.

In water year 2000, Flaming Gorge will be operated in aecordance with the Biologieal Opinion
on the Operation of Flaming Gorge (BOFG), issued in November 1992. The BOFG calls for high
spring releases to occur each year, timed with the peak of the Yampa River, so as to mimic
historic Green River flows.

December 1, 1999

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