WSP10742

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1991
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1991 Projected Operations 1992
• Water Supply Pro - Doc Type: Publication

Projected Plan of Operation. Water Year 1992

Determination of '1'i02(a) Storage"

Section 602(a)(3) of the Colorado Ri"'r Basin Project Act of
September 30, 1968 (Public Law 90.537), stipulatcs that
Colorado River water, which is not required to be. released
under article Ill{c) and llI(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 deli~rieswithout impairment of
annual consumptive uses in the Upper Basin.

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

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

Taking into consideration these relevant factors, the Secretary
has determined that the active storage in Upper Basin
resen'oirs forecast for September 30, 1992, exceeds the
"602(a) Storage" requirement under any reasonable range of
assumptions which might be applied to those items previously
listed. Therefore, the aceumulation of "602(a) Storage" is not
the criterion governing the release ofwatcr during the current
year.

Mexican Treaty Obligations

Annual calendar year schedules ofmonthlydcliycries of water
in the litnitrophe section of the Colorado Riycr, allotted in
accordance with the Mexican Water Treatysigned 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
Ihc 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~1:ex:ico
in calendar year 1992. Representatives of the Republic of
Mexico will be kept informed of operating schedules through
the United States Secdon of the Commission.

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