WSP01172

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1997
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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1997 DETERMINATIONS

The AOP provides guidance regarding reservoir storage and release conditions during the
upcoming year, based upon Congressionally mandated storage, release, and delivery criteria
and detenninations. After meeting these requirements, specific reservoir releases may be
modified as forecast inflows change in response to climatic variability and to provide
additional benefits to the projects' multiple purposes.

Upper Basin Reservoirs

The Operating Criteria provide that the annual plan of operation shall include a
detennination of the quantity of water 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, it has been detennined that the active storage in Upper Basin reservoirs
forecast for September 30, 1997 exceeds the storage required under Section 602(a) of the
Colorado River Basin Project 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 1997.

Section 602(a)(3) of the Colorado River Basin Project Act provides for the storage of
Colorado River water in Upper Basin reservoirs that the Secretary of the Interiorfinds
neceosary to assure deliveries to comply with Articles ill( c) and ill( d) of the 1922 Colorado
River Compact, without impainnent to the annual consumptive use in the Upper Basin. The
Secretary is required to make this detennination 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 PoweD:

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

to maintain, as nearly as practicable, active storage in Lake Mead equal to the active
storage in Lake PoweD, and

to avoid anticipated spills from Lake PoweD.

Storage equalization and/or spill avoidance criterion in accordance with Article ll(3) of the
Operating Criteria will control the releases from Glen Canyon Dam during water year 1997
unless the minimum objective release criterion in Article ll(2) is controDing. Under the most
probable inflow scenario Glen Canyon Dam will release 12,543 MCM (10.169 MAF).

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