WSP03527

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/2003
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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prepared an Environmental Assessment (EA) under the 1\atiooal Environmental Policy Act (1\'EPA)
to document the impacts oflhese proposed experimental flows. This EA incorporales a Biological
Assessment for the Fish and Wildlife Service under the Endangered Species Act (ESA). The
proposed experimental flows could be implemented in 1003 depending upon the outcome of the
NEP A process. and ESA consultations. The experimental flows would not alter the total volume of
Water to be released from Lake Powell in water year 1003.

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During water year 2003. the minimum release objective of8.23 maf(IO,152 mem) will be made
under the most probable and minimum probable inflow conditions. Above average inflow to Lake
Powell in 2003 may require that releases greater then 8.23 mafbe made to equalize the storage
between Lakes Powell and Mead. Under the probable maximum inflow scenario. approximately
11.0 maf (13.600 mcm) will be released.

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Because of less than full storage conditions in Lake PowelL resulting from three consecUlive years of
below nonnal runoff. releases for dam safety purposes are highly unlikely in 2003. Ifimplemented.
releases greater than powerplant capacity would be made consistent v,.'ith the 1956 Colorado River
Storage Project Act. the 1968 Colorado River Basin Project Act, and the 1992 Grand Canyon
Protection Act. Reservoir releases in excess of powerplant capacity required for dam safety purposes
during high reservoir conditions may be used to accomplish the objectives of the BeachlHabitat
Building Flow according to the terms contained in the Glen Canyon Dam ROD. and as published in
the Glen Canyon Dam Operating Criteria (62 Federal Register 9447. Mar. 3, 1997).

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Daily and hourly releases in 2003 will be made according to the parameters of the ROD for the Glen
Canyon Dam Final Environmental Impact Statement (GCDFEIS) preferred alternative, and the Glen
Canyon Dam Operating Criteria. as shown in Table 3. Exceptions to these parameters maybe made
during power system emergencies. or for purposes of humanitarian search and rescue. Experimental
flows. if implemented in 2003. may also require that releases exceed the parameters of the Glen
Canyon Dam Operating Criteria during the winter months of 2003.

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Releases from Lake Powell in \Vater year 2003 \\,'ill continue to reflect consideration of the uses and
purposes identified in the authorizing legislation for Glen Canyon Dam. Powerplant releases and
Beach/Habitat Building Flows will reflect criteria based on the findings. conclusions, and
recommendations made in the ROD for the GCDFEIS pursuant to the Grand Canyon Protection Act
of 1992. and any additional NEPA documentation regarding the April 24. 2002 AMWG
experimental flow proposal.

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The Secretary is considering information submined to the Depanment of the Interior by the Colorado
River Basin States (65 Federal Register 48537. August 8. 2000) whereby 602(a) storage
requiremenls determined in accordance with Anicle II (1) of the Operating Criteria would utilize a
\.alue of not less than 14.85 maf(elc\.ation 3630 feet) for Lake Powell through the year 2016. The
Secretary. Ihrough Reclamation. may initiate a NEPA process in 2003 to determine the impacts of
the Basin States proposed 602(a) storage.

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December 13. 2002

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