WSP03527

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/2003
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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2003 DETER~II:-;ATIO:-;S

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The AD? provides guidance regarding reservoir storage and release conditions during the
upcoming year. based upon congressionally mandated and authorized storage. release. and delivery
criteria and detemlinations. After meeting these requirements. specific reservoir releases may be
modified within these requirements as forecast inflows change in response to climatic variability and
[0 provide additional benefits coincident to the projects' multiple purposes.

Upper Basin Reservoirs

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The Operating Criteria provide that the annual plan afoperation shall include a dctemlination of the
quantity ofw3ter considered necessary to be in Upper Basin storage at the end of the water year.
Taking into consideration all relevant factors required by the Operating Criteria. and funher
considering information submitted to Reclamation by the Colorado River Basin Slates (65 Federal
Register 48537. August 8. 2000) which would utilize a value not less than 14.85 million acre. feet
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(elevation 3.630 feet) for Lake Powell. it is detemlined that the active storage in Upper Basin
reservoirs forecast for September 30. 2003. exceeds the storage required under Section 602(a) of the
Colorado Ril'er Basin Projecf Act under any reasonable range of assumptions which might be
applied, Therefore. ~602(a) Storage" is not the criterion controlling the release of water from Glen
Canyon Dam during water year 2003.

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Section 602(a)(3) of the Colorado Rh'er Basil! Project Act provides for the storage of Colorado
River water in Upper Basin reservoirs that the Secretary finds necessary to assure deliveries to
comply with Articles lI1(c) and III(d) of the 1922 Colorado Rh'er Compact. without impairment to
the annual consumptive use in the Upper Basin. Pursuant to Section 602(b). as amended. the
Secretary is required to make this determination after consultation with the Upper Colorado River
Commission and representatives from the three Lower Division States. and after taking into
consideration all relevant factors including historic stream flows. the most critical period of record.
the probabilities of water supply. and estimated future depletions. Water not required to be so stored
will be released from Lake Powell:

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to the extent it can be reasonably applied in the States of the Lower Division to the uses
specified in Article II1(e) of the 1922 Colorado Ril'cr Compact. but these releases will not be
made when the active storage in Lake Powell is less than the active storage in Lake Mead.

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to maintain. as nearly as practicable. acti\-e storage in Lake .Mead equal to the active storage
in Lake Powell. and

to avoid anticipated spills from Lake Powell.

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The minimum objective release criterion will control the annual release from Glen Canyon Dam
during water year 2003 in accordance with Article II(2) of the Operating Criteria unless spill
a\'oidance and10r the storage equalization criteria in Article 1I(3) is controlling. Under the most
probable inflow scenario. Glen Canyon Dam will release 8.23 maf(1O.150 mcm).

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December 13. 2002

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