Summary Report ‎(Working Draft)‎ Modeling of Reservoir Management Strategies for Lakes Powell and Mead December 2005

• Description: Summary Report ‎(Working Draft)‎ Modeling of Reservoir Management Strategies for Lakes Powell and Mead December 2005
• State: CO
• Title: Summary Report ‎(Working Draft)‎ Modeling of Reservoir Management Strategies for Lakes Powell and Mead December 2005
• Water Supply Pro - Doc Type: Meeting

Modeling Results for
Colorado River Basin States' Modeling of
Colorado River and Reservoir Management Strategies
2.2.2 Tiered Release
The concept of Tiered Release is to set the minimum annual release from Powell
based on its projected end -of -water -year (EOWY) elevation. As the reservoir
declines, releases would be limited to preserve storage in Powell. The Tiered
Release strategy is comprised of four levels:
Tier
Powell Elevation (in feet)
Powell Release (in MAF)
1
Above 3630
Equalize or 8.23
2
Between 3630 and 3550
8.23
3
Between 3550 and 3525
7.80
4
Below 3525
7.48
2.2.3 Balancing
The concept of balancing is similar to equalization, but is not tied to 602(a).
Ideally, if one reservoir is in trouble, balancing would help mitigate impacts to
that reservoir. The Balancing strategy focuses on the condition of both reservoirs
to determine how much water to release from Powell. This strategy attempts to
balance the contents of Powell with the contents of Mead within minimum and
maximum release constraints from Powell. The release structure for the Balancing
strategy is as follows:
Powell Elevation
in feet)
Mead Elevation
(in feet)
Powell Release in MAF)
Above 602(a) storage
requirement
Not relevant
Equalize or 8.23
Between 602(a) storage
requirement and 3550
Above 1050
Balance min /max 7.0/9.5
Below 1050
8.23
Below 3550
Not relevant
Balance min /max 7.0/9.5
2.2.4 Hybrid
The Hybrid release strategy combines features from the Tiered Release and
Balancing strategies. Conceptually, when Powell is in "good" condition it will
equalize according to normal operations. When Powell is in "fair" condition
(between the 602(a) storage requirement and 3550) it will release 8.23 MAF;
unless Mead is in "poor" condition (less than 1050), in which case Powell will
release more water to balance contents with Mead. When Powell is in "poor"
condition (between 3550 and 3525) its release will be lowered to 7.48 MAF
regardless of Mead's condition to preserve storage in Powell. When Powell is in
"very poor" condition (below 3525) and loss of power production appears
eminent, balancing will govern operations. In all circumstances, balancing
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