BOARD00148 ‎(2)‎

• Board Meeting Date: 3/12/2007
• Description: WSP Section - Colorado River - DEIS - Development of Lower Basin Shortage Guidelines and Coordinated Management Strategies for Lake Powell and Lake Mead, Particularly Under Low Reservoir Conditions
• Board Meetings - Doc Type: Memo

March 12-13,2007 Board Meeting
Agenda Item 9
Page 2 of5

May 2, 2005 the Secretary initiated a NEP A process for the development of Lower Basin .
Shortage Criteria along with a review qfthe 1970 Coordinated Long-Range Operating
Criteria for Colorado River Reservoirs (Criteria) to evaluate the potential for changes
in the operations of Lakes Powell and Mead under low reservoir conditions. The
deadline for completiion of the NEPA p~ocess is December 31,2007.
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To date, the Bureau ofReclama~ion (Reclamation) has completed the Scoping
Process and identified 5 alternatives th~t it will be evaluate in the NEP A process: I) the
Basin States Proposal; 2) a conservatio~ before shortage proposal developed by the
environmental community; 3) a water sppply alternative; 4) a preservation of reservoir
storage option; and, 5) a no action alternative that continues the existing coordinated
long-range operating criteria. On Febr4ary 28, 2007 Reclamation released the draft EIS
for review with comments on the DEIS lidue back on April 30, 2007. A final EIS is
anticipated in September 2007 and the ~ecord of Decision issued by December 31,2007.
Attached hereto is the DEIS Executive ~ummary which includes a matrix providing a
brief overview of the alternatives and tables describing the results of their analysis. The
full document can be reviewed online at
www.usbr.gov/lclregion/programs/strategies.html. We note with interest that the DEIS
does not contain a preferred alternative,i thus comments will be extremely important to
the ultimate outcome ofthe ROD.

7-State Alternative Overview

Lower Basin Shortage Guidelil;tes: The Lower Basin proposes to take shortages .
in incremental amounts that are tied to reservoir elevations in Powell and Mead. The
shortage increments are 400,000 AF, 500,000 AF or 600,000 AF annually, larger
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amounts are possible but the Secretary ",;ould need to consult further with the states
before making larger reductions. Most of the shortage will be born by the Central
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Arizona Project, with lesser shares of ea9h shortage step assumed to be chargeable to
Mexico (16.67 %) and Nevada (3.33 %).1 Further details of the split remain to be worked
out and could depend on how the alternative is implemented.

Coordinated Operations of Po~ell and Mead under Low Reservoir
Conditions: Under the current Long-Range Operating Criteria for Colorado River
Reservoirs, Lake Powell and Lake Mead ':equalize storage whenever Powell storage is
greater than storage in Lake Mead and Pqwell storage is above the 602(a) storage level.
The 602(a) storage level is the volume o~water deemed necessary in Lake Powell,
Flaming Gorge, Aspinall, and Navajo to assure to the extent possible that the Upper
Basin can sustain its current level of dev~lopment without having to curtail uses during a
drought to assure that the 75 million acre+foot (MAF) flow at Lee Ferry over a
continuous 1 O-year period criterion in the. Colorado River Compact is satisfied. The
current 602(a) storage requirement is ele~ation 3630 or approximately 14.85 MAF.
When Powell is below the 602(a) level, operations at Glen Canyon Dam seek to maintain
a minimum objective release of 8.23 M~ (7.5 MAF per year plus one-half ofthe 1.5
MAP delivery obligation to Mexico, the Hltter condition to which the Upper Basin .
strongly disagrees with). The result is th~~ Lake Powell absorbs the impact of the drought .