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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habitat area (Farmington to Lake Powell). The Flow Recommendations call for an 3\'Cragc weekly
flow of between 500 cfs (14 ems) and 1.000 cfs (28 ems) in this reach of the river.

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Reclamation has begun a National Environmental Policy Act (NEP A) process on the implementation
of an operation at Navajo Dam that meets these Flow Recommendations or a reasonable alternative
to them. A Notice of Inten! to prepare an Environmentallmpac! Statement (EIS) was filed on
OClober I. 1999. in the Federal Register. A draft EIS was released on September 4. 2002. The
completion oflhe final EIS and Record of Decision is scheduled to occur in 2003.

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Under the most probable and maximum probable inflow scenarios during water year 2003. ~avajo
Reservoir is not expected to fill. Releases from the reser\"oir will be held near 500 cfs (14 ems)
through the fall and winter months and large releases will likely be made in .\lay and June pursuant
to thc Flow Recommendations to improve the habitat and provide better spawning conditions for
endangered fish in the San Juan River.

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lake PO\'tell

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lake Powell began water year 2002 \\'ith 20.9 maf(25.800 mem) of storage (86 percent of capacity).
From October 2001 through Januarv 2002. releases from Glen Canvon Dam were scheduled to
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achicve equalization ofstorage belween Lake i\.1ead and Lake Powell by the end of water year 2002
in accordance with Anic1e 11(3) of the Operating Criteria. Inllow projections were reduced in
February, 2002 with forecasted April through July unregulated inflow to Lake Powell only 7.7 maf
(5,800 mcm) or 59 percent of average. This forecast was sufficiently low that storage equalization no
longer became the governing criterion in the 2002 operation. From February. 2002 through the end
of the water year. releases were scheduled 10 maintain the minimum release objective from lake
Powell of 8.23 maf (10.150 mcm) for water year 2002 in accordance with Anicle 11(2) of the
Operating Criteria.

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April through July unregulated inflow into Lake Powell in waler year 2002 was 1.12 maf (1.380
mcm). or 14 percent ofavcrage. Water year 2002 unregulated inflow was 3.06 maf(3.770 mcm). or
25 percent of average. Unregulated inflow in 2002 was the lowest recorded since the closure of Glen
Canyon Dam. The previous low occurred in 1977.

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Lake Powell nonnally increases in elevation during the April through JulyrunofTperiod. Inflow was
so low in the spring of 2002. however. that reservoir storage in lake Powell continued to decline
throughout the runoff period. The elevation of Lake Powell on September 30. 2002 was 3.626.5 feet
(1.105.4 meters) (73.5 feet from full). Lake Powell ended water year 2002 with 14.5 maf(17.800
mcm) of storage (59 percent of capacity).

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On April 24. 2002. membcrs of the Glen Canyon Adaptive Managemenl Work Group (AM\\'G)
recommended to the Secretary that a two-year experimental flow lest be made from Glen Canyon
Dam beginning in water vear 2003. The recommendation addressed the decline of two kc\' resources
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in the Grand Canyon: sediment and population viability of endangered humpback chub.

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Reclamation. the :'\ational Park Service. and the Uniled States Geological Survey have jointly

December 13. 2002

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