WSP01715

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1992
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1992 Projected Operations 1993
• Water Supply Pro - Doc Type: Publication

Projected Plan of Operation - Water Year 1993

Determination of "602(a) Sto....ge"

Section 602(.)(3) of the Colnrado River Basin Project Act of
September 30, 1968 (Public Law 90-537), stipulates that
Colorado River water, which is not required to be released
under article III ( c) and III( d) of the Colorado River Compact,
be stored in Upper Basin reservoirs to the extent the Secretary
of the Interior (Secretary) finds such storage necessary to
assure compact deliveries without impairment of annual
consumptive uses in the Upper Basin.

Article II of the Operating Criteria provides that the annual
plan of operation shall include a determination by the
Secretary of the quantity of water considered necessary to be
in Upper Basin storage as of September 30 of the current year.

This determination shall consider all applicable laws and
relevant factors including, but not limited to, the following:
(a) historic streamflows; (b) the most critical period of record;
(c) probabilities of water supply; (d) estimated future
depletions in the Upper Basin, including the efFects of
recurrence of critical periods of water supply; (e) the "Report
of the Committee on Probabilities and Test Studies to the
Task Force on Operating Criteria for the Colorado River,"
dated October 30, 1969, and such additional studies as the
Secretary deems necessary; and (I) the necessity to aSSure that
Upper Basin consumptive uses are not impaired because of
failure to store sufficient water to assure deliveries under
Section 602(a)(1) and (2) of Public Law 90-537.

Taking into consideration these relevant factors, tbe Secretary
has determined that the active storage in Upper Basin
reservoirs forecast for September 30, 1993, exceeds the
"602(a) Storage" requirement under any reasonable range of
assumptions which might be applied to those items previously
listed. Therefore, the accumulation of "602(a) Storage" is not
the criterion governing the release of water during the current
year.

Mexican Treaty Obligations

Annual calendar year schedules of monthly deliveries of water
in the limitrophe section of the Colorado River, allotted in
accordance with the Mexican Water Treaty signed in 1944, are
formulated by the Mexican Section and presented to the
United States Section, International Boundary and Water
Commission (Commission), before the beginning of each
calendar year. Upon 30 days advance notice to the
United States Section, Mexico has the right to modify, within
the total schedule, any monthly quantity prescribed by the
schedule by not more than 20 percent.

Based on the current water supply conditions, the
United States will make scheduled deliveries of 1,500,000
acre-feet of Colorado River water to the Republic of Mexico
in calendar year 1993. Representatives of the Republic of
Mexico will be kept inFormed of operating schedules through
the United States Section of the Commission.

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