WSP06774

• File Number: 8282.600.10
• Description: Colorado River Annual Operating Plan
• Basin: Colorado Mainstem
• Date: 12/14/1999
• Author: USDOI/BOR
• Title: 29th Annual Report and 2000 Annual Operating Plan for Colorado River System Reservoirs
• Water Supply Pro - Doc Type: Publication

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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 offish 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 seenarios:
the probable maximum, most probable, and probable minimum reservoir inflow conditions. River
operations under the plan are modified during the year as runoffpredictions are adjusted to reflect
existing snowpack, basin storage, and flow conditions.

Summary

Upoer Basin Deliverv, Storage equalization and the avoidance of spills will control the annual
releases from Glen Canyon Dam in accordance with Article 11(3) of the Operating Criteria unless
the minimum objective release eriterion in Article 11(2) is controlling.

Lower Basin Delivery. Downstream deliveries and/or flood control parameters are expected to
control the releases from Hoover Dam,

Taking into account (1) the existing water storage conditions in the basin, (2) the most probable
near-term water supply conditions in the basin, and (3) that the beneficial consumptive use
requirements of Colorado River mainstream users in the Lower Division States are expeeted to
be more than 9,250 MCM (7.5 MAF), the surplus condition is the eriterion governing the
operation of Lake Mead for calendar year 2000 in accordance with Article ID(3)(b) of the
Operating Criteria and Article 1l(B)(2) ofthe decree in Arizona v. California.

Any Lower Division State will be allowed to utilize water apportioned to, but unused by, another
Lower Division State, in accordance with Article 1l(B)(6) of the decree in Arizona v. California.

1944 Mexican Water Treaty Delivery. A volume of2,097 MCM (1.7 MAF) of water will be
allowed to be scheduled for delivery to Mexico during calendar year 2000 in accordance with
Article 15 of the 1944 Mexican Water Treaty and Minute No. 242 of the International Boundary
and Water Commission.

December I, 1999

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