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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accomplish the objectives of the Beach/Habitat Building Flow described in the Record of
Decision for the Glen Canyon Dam Final EIS (GCDFEIS).

Releases from Lake Powell in water year 1999 will continue to reflect consideration of the uses - p../J!f-j
and purposes identified in the 1970 Operating Criteria. ~- '. 1992 Grand Canyon Protection L<:-l a. '~
Act, including ecological impacts to the Grand Canyon. Daily and hourly releases will continue To re'{Z;cJ:.-
to be made according to the parameters of the Record of Decision for the GCDFEIS preferred ~otf::~
alternative, and published in the Glen Canyon Dam Operating Criteria (62 Fed. Reg. 9447, Mar. "'-9...,,,
3,1997), as shown in the following table: ;;~~l'dS""
'~"-f.lecfeJ
I" f-~

Parameter (cms) (cfs) conditions
Maximum flow (1) 708.0 25,000
Minimum flow 141.6 5,000 nighttime
226.6 8,000 7:00 am to
7:00 pm
Ramp rates
ascending 113.3 4,000 per hour
descending 42.5 1,500 per hour
Daily fluctuations (2) 141.6/226.6 5,000/ 8,000

Table 3. Glen Canyon Dam release restrictions

(I) to be evaluated and potentially increased as necessary and in years when delivery to the
Lower Basin exceeds 10,152 MCM (8.23 MAF)

(2) Daily fluctuations limit is 141.6 cms (5,000 cfs) for months with release volumes less
than 740 MCM (.600 MAF); 169.9 cms (6,000 cfs) for monthly release volumes of 740 to
987 MCM (.600 to .800 MAF); and 226.6 cms (8,000 cfs) for monthly volumes over 990
MCM (.800 MAF)

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