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'~I .,;; ~i MONITORING OF INTERIM FLOW CRITERIA The operating criteria parameters--maximum daily flows, minimum daily flows, daily fluctuation, and ramp rates--are monitored at the Glen Canyon Dam using Reclamation's . Supervisory Control and Data Acquisition (SCADA) system. The discharge and river stage changes are monitored at downstream gaging stations near Lees Ferry and Grand Canyon Village. The SCADA data at Glen Canyon Dam is recorded in megawatts of energy and require conversion to flow--cubic feet per second (cfs). From June 1, 1993, through November 30, 1993, the maximum flow of 20,000 cfs was adhered to as shown on the charts in Attachment A. The minimum flow of 5,000 cfs at night and 8,000 cfs between 7 a.m. and 7 p,m. was also met throughout the period. The release volumes of the individual months were as follows: '.; June 1993 617,986 acre-feet July 1993 910,000 acre-feet August 1993 910,000 acre-feet September 1993 666,000 acre-feet October 1993 550,000 acre-feet November 1993 600,000 acre-feet .:.1 . :-r; .> , '., Ramp Rates - Ramp rates may be exceeded under the criteria for system disturbances, regulation, and other emergency situations to allow for power system operation adjustments. The ramp rates were exceeded periodically as a result of system disturbances and regulation responses to power demands. The deviations that occurred were resolved within the hour that they occurred in. All deviations were reported to the Glen Canyon Environmental Studies (GCES) office and appropriate monitoring actions were initiated. The number of times ramp rates were exceeded has been consistently reduced as operators have become more experienced with projecting power system adjustments. ';; ",ii ~ II! ') .., s :f Attachment B shows the traces of discharge and river stages at Lees Ferry and Grand Canyon Village for June 1993 through November 1993. MONITORING OF EXCEPTION CRITERIA The exception criteria are monitored at Glen Canyon Dam using Reclamation's SCADA system. Several deviations from the interim flow criteria occurred, primarily due to electrical system emergencies caused by electrical transmission system and generation capability. None of the system deviations lasted longer than 1 hour (see Attachment B).