WSP09160

• File Number: 8220.101.08
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 6/1/1993
• Author: USDOI - BOR
• Title: Glen Canyon Dam - Monitoring of Interim Operating Criteria - June 1993 through November 1993
• Water Supply Pro - Doc Type: Report/Study

GLEN CANYON DAM

MONITORING
OF
INTERIM OPERATING CRITERIA

June 1993 through November 1993

Bureau of Reclamation

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This document summarizes the monitoring of Interim Operating Criteria for Glen
Canyon Dam from June 1993 through November 1993. This is the sixth report of
monitoring of operating criteria, with the first report covering August through December
1991, the second report covering January through April 1992, the third report covering
May through September 1992, the fourth report covering October 1992 through February
1993, and the fifth report covering March through May 1993. Summaries will be
published periodically throughout the interim operation period.

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BACKGROUND

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-The Glen Canyon Dam Interim Operating Criteria were implemented on November 1,
1991, following a 3-month testing of the proposed interim flow criteria. An Environ-
mental Assessment was completed in October 1991 with a Finding of No Significant
Impact. The Interim Operating Criteria will remain in effect until completion of the
Glen Canyon Dam Environmental Impact Statement, scheduled for completion in
October 1994, and Record of Decision scheduled shortly thereafter.

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Exception Criteria. The Western Area Power Administration and the Bureau of
Reclamation signed an interagency agreement on October 21, 1991, implementing
exception and associated interim operating criteria, including financial exception criteria.

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The exception criteria allow deviation from the interim flow criteria for response to
power system disturbances or other emergency situations and for power system
regulation. The agreement incorporates emergency and system regulation provisions
which were in place during research flows and, in addition, includes "financial criteria" as
a means of avoiding the expense of purchasing replacement firm capacity and energy
during the interim period. The financial criteria element is conditional. The primary
conditions include:

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- limiting the use of financial criteria to not more than 3 percent of the time
(22 hours) in any consecutive 3D-day period
- periodic review and renewal, and
- reporting the use and costs associated with the financial criteria