8128

• UCREFRP Catalog Number: 8128
• Author: U.S. Bureau of Reclamation.
• Title: Operation of Glen Canyon Dam\
• USFW Year: 1995.
• Copyright Material: NO

Description of Alternatives
UNRESTRICTED FLUCTUATING FLOWS
The two unrestricted fluctuating flow alternatives would allow flows to
vary, as necessary, for power generation purposes.
No Action Alternative
Minimum Maximum Allowable daily Ramp
releases releases fluctuations rate
(cfs) (cfs) (cfs/24 hrs) (cfathr)
1,000 Labor Day 31,500 30,500 Labor Day Unrestricted
to Easter to Easter
3,000 Easter to 28,500 Easter to
Labor Day Labor Day
Annual Release
Volume
The No Action Alternative (historic operations) is presented first to
provide an understanding of baseline conditions and operations at Glen
Canyon Dam. Many resources in the river and adjacent riparian zone
developed in response to dam operations under no action conditions.
Thus, this alternative provides the basis for impact comparison.
Within the overall CRSP purpose, the objective of the No Action
Alternative is to produce the greatest amount of firm capacity and energy
practicable while adhering to the releases required under the "Law of the
River." Under no action, Glen Canyon Dam operations would be the same
as they were from 1963-when the dam was placed in operation-until the
research flows began in June 1990. This alternative would continue
operations established under the Criteria for Coordinated Long-Range
Operation of Colorado River Reservoirs (Long-Range Operating Criteria)
including daily fluctuating releases. The maximum allowable discharge
during fluctuations is 31,500 cfs. Releases fluctuate when the dam is being
operated to follow power system load changes, to produce peaking power,
to regulate the power system, or to respond to power system emergencies.
Annual release volume is based on inflow and remaining space in Lake
Powell and Lake Mead. Annual release volumes vary greatly, but all
adhere to the Long-Range Operating Criteria objectives of an 8.23-maf
minimum annual release and equalized storage between the two
reservoirs. Annual releases greater than the minimum are permitted to
avoid anticipated spills and to equalize storage.
Glen Canyon Dam EIS Summary 17