BOARD00060 ‎(3)‎

• Board Meeting Date: 1/24/2007
• Description: WSP Section - Colorado River 7-State Agreement Approval
• Board Meetings - Doc Type: Memo

Common assnmptions to aU Alternatins:
1. First year of modeling under above-identified alternatives is 2008 and extends to 2060 (53 years) (Note: water elevation for January
2. Future hydrologic sequences will be based on the 99::Y!lar natural flow record JJ 906-2004 J.

1,

2008 will be projected using the June 2006 24 -Month Study).

6/19/2006, Pre-decisional

. Minimum objective release of8.23 MAF if
Powell is above 3590'unless storage equalization
releases are required.
.7.80 MAF release between 3555' and 3590'
. Balancing below 3555'

. Maximum total Lake Mead storage through
extraordinary conservation andlor augmentation of
2.6 MAF.
. ICS puts/takes for States, Mexico,
government.
. System Tax of 10% on all puts.

Reservoir Storage
Alternative

and the Federal

. Beginning in 2008, surplus declarations revert to the
70R strategy/flood control.

Water Supply
Alternative

. Stepped

. Release full annual entitlement amounts until drawn
down to top of dead pool: then outflow = inflow.

shortages up to

1.2 MAF

. Minimum objective release of 8.23 MAF unless
storage equalization releases are required.
. Balancing if Powell below 3575'or Mead below
1075'.

. No water management/accounting mechanism for
storage and delivery of water conserved through
extraordinary water conservation andlor water
augmentation programs.

. Extension of the existing Interim Surplus Guidelines
through 2025

Conservation
Before Shortage
Alternative

. Absolute protection of SNW A intake (elevation
1000') at Lake Mead.

. Under low reservoir storage conditions, either
reduce Lake Powell release or balance contents
depending on projected Lake Mead and Lake
Powell elevations.

. Maximum total Lake Mead storage through
extraordinary conservation andlor augmentation of
4.2 MAF.
. ICS puts/takes for States, Mexico, and the Federal
government.
. Dedicated environmental releases.
. System Tax of 5% on all puts.

. Modification of Interim Surplus Guidelines to
eliminate Partial Domestic Surplus condition.
. The modified guidelines are implemented from 2008
through 2025.

year.
. System Tax of 5% on all puts.
. Maximum delivery from Lake Mead of water
developed by extraordinary conservation andlor
augmentation of 1.0 MAF per year.

Basin States
Pretiminary
Alternative

. Stepped shortages up to 600 KAF.
. Initiate efforts to develop additional guidelines for
shortages if Lake Mead falls below elevation 1025'
(Note: includes reconsultation with Basin States).

. Under low reservoir storage conditions, either
reduce Lake Powell release or balance contents
depending on projected Lake Mead and Lake
Powell elevations.

. Maximum total Lake Mead storage through
extraordinary conservation andlor augmentation of
2.1 MAF.
. Maximum created storage credit of 625 KAF per

. Modification oflnterim Surplus Guidelines to
eliminate Partial Domestic Surplus condition.
. The modified guidelines are implemented from 2008
through 2025.

No Action
Alternative

. Two level shortage strategy - probabilistic protection
of elevation 1050' at Lake Mead (80PI 050) and
absolute protection of elevation 1000' at Lake Mead.

. Minimum objective release of 8.23 MAF unless
storage equalization releases are required.
.8.23 MAF until drawn down to top of dead pool:
then outflow = inflow (conditioned on outlet
constraint)

. No water management/accounting mechanism for
storage and delivery of water conserved through
extraordinary water conservation andlor water
augmentation programs.

. No modification or extension of the
Guidelines which end in 2016.
. Beginning in 2017, surplus declarations revert to the
70R strategy/flood control.

Alternatives

Shortage Guidelines
to reduce deliveries/releases from
Lake Mead

Coordinated Reservoir Operations
(Lake Mead & Lake Powell)

Lake Mead Storage and Delivery of Conserved
and Non-system Water

Interim Surplus

Interim Surplus Guidelines
for deliveries/releases from Lake Mead

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Modeling Assumptions for Draft Alternatives
Working Draft: June 16, 2006 version

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