WSP00672

• File Number: 822.600.10
• Description: Colorado River Annual Operating Plan - Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1993
• Author: USDOI/BOR
• Title: Annual Operating Plan
• Water Supply Pro - Doc Type: Annual Report

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used to satisfy beneficial consumptive use requests of mainstream users in other Lower
Division States as provided in the decree in Ariwna v. California.

Consistent with the above determinations and in accordance with other provisions of "The
Law of the River," the AOP was developed with "appropriate consideration of the uses of
the reservoirs for all purposes, including flood control, river regulation, beneficial
consumptive uses, power production, water quality control, recreation, enhancement of
fish and wildlife, and other environmental factors" (Operating Criteria Article 1(2)).

Since the hydrologic conditions of the Colorado River Basin can never be completely
known in advance, the AOP addresses the operations resulting from three different
hydrologic scenarios, the probable maximum, most probable, and probable minimum
reservoir inflow conditions. River operations under the plan are modified during the year
as runoff predictions are adjusted to reflect existing snowpack, basin storage, and flow
conditions.

Summary

Upper Basin Delivery. Glen Canyon Dam will be operated to meet the minimum
objective release of 8.23 million acre-feet (MAP) for water year 1993 in accordance with
Article 11(2) of the Operating Criteria.

Lower Basin Uses. Hoover Dam releases (including pumping from Lake Mead) will be
sufficient to satisfy up to 7.5 MAP of reasonable beneficial consumptive use requirements
by mainstream users in the Lower Division States during calendar year 1993 in
accordance with Article ill(a) of the Operating Criteria and Article 1I(B)(1) of the decree
in Arizona v. California. Any Lower Division State will be allowed to utilize
apportioned, but unused, water from another Lower Division State, in accordance with
Article 1I(B)(6) of the decree in Arizona v. California; provided that, the calendar year
1993 consumptive use by mainstream Lower Division States users does not exceed
7.5 MAP.

1944 Mexican Water Treaty Delivery. The guaranteed annual quantity of 1.5 MAP of
water will be delivered to Mexico during calendar year 1993 in accordance with
Article 15 of the 1944 Mexican Water Treaty and Minute No. 242 of the mwc.

Reservoir Qperations. Due to the amount of vacant storage space in the Colorado River
reservoirs at the beginning of water year 1993, no flood control releases are anticipated
from Hoover Dam pursuant to the Hoover Dam Flood Control Regulations, and no
releases are contemplated from Glen Canyon Dam to avoid anticipated spills or to
equalize active storage in Lakes Mead and Powell except under the probable maximum
flow scenario. Water releases from each of the Colorado River reservoirs will be in
accordance with minimum flow requirements, reservoir operating criteria, and target