WSP05551

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/2002
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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Releases of 5,000 efs (142 ems) were maintained for 27 days. After the completion of the large
spring releases, releases were gradually reduced to 500 efs (14 ems). Except for a low flow test
conducted in July, releases were held at 500 cfs (14 ems) for the remainder of2001.

As part of the EIS process, Reclamation performed a low flow test during July of200 1. Releases
during this test were 250 efs (7 ems), The test was conducted to gather physical, chemical,
hydrologic, and hydraulic engineering data to evaluate the effects of a 250 efs (7 ems) Jow.f1ow.
After completion of the low flow test, releases were again restored back to 500 efs (14 ems).

In water year 2002, Navajo Reservoir is expected to nearly fill under the most probable inflow
scenario. Releases from the reservoir will be held near 500 cfs (14 cms) through the fall and
winter months and large releases will likely be made in May and June pursuant to the flow
recommendations to improve the habitat and provide better spawning conditions for endangered
fish in the San Juan River.

Lake Powell

Lake Powell began water year 2001 with 20,9 MAF (25,800 MCM) of storage (86 percent of
capacity). From October 2000 through June 2001, releases from Glen Canyon Dam were
scheduled to achieve equalization of storage between Lake Mead and Lake Powell by the end of
water year 200 I in accordance with Aniele 11(3) of the Operating Criteria. Hydrologic conditions
became drier as water year 2001 progressed, however. Forecasted April through July
unregulated inflow to Lake Powell in January, 2001 was 92 percent of average, By July, 2001,
forecasted inflow had dropped to 4.30 MAF (5,304 MCM) or 56 percent of average. This
forecast was sufficiently low that storage equalization no longer became the governing criterion
in the operation. From July 2001 through the end of the water year, releases were scheduled to
maintain the minimum release objective from Lake PowelI of8.23 MAF (10,150 MCh1) for water
year 200 I in accordance with Aniele II(2) of the Operating Criteria,

April through July unregulated inflow into Lake Powell in wateryear 2001 was 4,30 l\1AF (5,300
MCM), or 56 percent of average. Water year 2001 unregulated inflow was 6.96 MAF (8,580
MCM), or 59 percent of average, Lake Powell reached a peak elevation ofJ,673,O feet (I, 119.5
melers) on July 1,2001 (27,0 feel from full). Lake Powell ended water year 2001 with 19, I MAF
(13,600 MCM) of storage (79 percent of capacity),

On 7 days during water year 200 I, Glen Canyon Dam responded to stage III power emergencies
in California, These responses occurred on February 15, March 19, March 20, May 7, May 8,
May 31 and July 2. During most of these responses, generation was increased by about 300
megawatts (approximately 7,000 cfs) above that prescheduled, Ascending ramp rates and daily
fluctuations exceeded the parameters of the ROD for the Glen Canyon Dam Final Environmental
Impact Statement (GCDFEIS) preferred alternative on each of these occasions. Emergency
exception criteria in the ROD, however, allow powerplant operations to exceed the parameters
of the preferred alternative when necessary to respond to emergency situations. On each of the

Oclober 15, 200 I

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