WSP12637

• File Number: 8282.300
• Description: Colorado River Operations and Accounting - Lower Basin Administrative Procedures
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 8/1/1996
• Author: DOI-BOR
• Title: Description and Assessment of Operations-Maintenance and Sensitive Species of the Lower Colorado River - Volume I - Report - 08-01-96
• Water Supply Pro - Doc Type: Report/Study

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Ou2327

An analysis of the "Water Control Manual for Flood Control Hoover Dam and Lake Mead
Colorado River, Nevada and Arizona" reveals that of the various triggers for releases studied
in the preparation of the manual, very little difference was identified in the river flows under
the different scenarios, except in extreme and rare events. The major effects occurred in
upper basin storage" with resultant changes in the probability of a system drought.

A description of the;: operation process for flood control for Hoover Dam is presented in part
C.!. entitled "Flood Control" of this document.

The COE is not responsible for the flood control criteria related to Davis Dam and
Parker Dam, although the respective lake elevations and the operation of Davis Dam and
Parker Dam are affected and, in part, determined by the flood control releases from
Hoover Dam. The decision to include flood control as an operational parameter and the
operation of the flood control aspects of Davis and Parker Dams fall within the Secretary's
discretion. In another sense, the inclusion of the flood control aspects of Davis and
Parker Dams is prescribed in the Law of the River, for the waters entering the system via
tributary runoff become mainstream water, and the release of these waters is subject to the
requirements and prohibitions placed upon the Court decree further described in this section.
The discretionary component of operational water elevation levels of Davis Dam and
Parker Dam, which reflect flood control as one of the parameters and as prescribed by
Reclamation for Davis Dam and Parker Dam, are shown in Figures 15 (Lake Havasu
Operational Constraints) and 17 (Lake Mohave Operational Constraints) and are within the
scope of this consultation.

2. The Role of the Secretary as Watermaster of the Lower Colorado River
Basilll for Delivery and Storage of Water

Over the past 74 years, the upper and lower basins and the associated body of laws, Court
decrees, regulations, and contracts have developed into two very different bodies of law for
the upper and lower basins. The following synopsis establishes the authority and operational
framework of the Secretary in the operation of the lower Colorado River basin. Reclamation
serves as the representative of the Secretary in the implementation of these responsibilities.

The Colorado River Compact of 1922 divided the Colorado River into an upper and lower
Basin, and Article III (a) provided 7.5 maf of water to the lower basin States. Article III(b)
gave the lower basin right to increase its beneficial consumptive use of water by 1 maf per
year. Article III(c) requires that the burden of any deficiency in meeting international
commitments for supplying Colorado River water to Mexico shall be borne equally between
the upper basin and lower basin. Article III (d) requires that the upper basin States will not
cause the flow of the river at Lees Ferry to be depleted below an aggregate of 75 maf for
any 10 consecutive years. Article III(e) states that water will not be withheld by the upper
basin States or delivery required by the lower basin States, that cannot reasonably be applied
to domestic and agricultural uses.

The Boulder Canyon Project Act of 1928 federalized the lower basin and established the

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