WSP11872

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1981
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1981 Projected Operations 1982
• Water Supply Pro - Doc Type: Publication

On September 30, 1981, the active content of
Lake Powell was 20,751 ,000 acre-feel and the
storage at Lake Mead was 21.870,000 acre-
feel. Releases from Lake Powell amounted to
8.295,000 acre-feel. By the end of the water
year, the goals of the 1981 operation plan tor
the maior storage reservoirs in the system
had been achieved,

Projected Plan of Operation
Under Criteria - Water Year 1982

lone boa1 dots lhe waters 01 lake Mead

Determination 01 "802(a) Storage"
Sec, 602(aX3) of the Colorado River Basin
Project Act of September 30. 1968. (Public
Law 90-537). provides for the slorage of
Colorado River water, not required to be
released under article i11(c)and i11(d) of the
Colorado River Compact in Upper Basin
reservoirs, to the extent the Secretary finds it
necessary \0 aSSUTe compac' deliveries
without impairment of annual consumptive
uses in the Upper Basin,

Arlicle II of the "Criteria for Coordinated Long-
Range Opera lion of Colorado River Reservoirs"
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 Juture depletions in the Upper
Basin, including the effects of recurrence of
c"tical periods of water supply; (e) the
"Reporf of the Committee on Probabilities and
Test Studies to the Task Force on Operating
Criteria tor the Coiorado River," dated
October 30. 1969, and such additional studies
as the Secretary deems necessary; (f) the
necessity to assure that Upper Basin
consumptive uses are not impaifea because
of failure to store sufficient water to aSsure

deliveries under See, 602(aX1) and (2) of
Public Law 90-537,

Taking into consideration these relevant
factors, the Secretary has determined that the
active storage in Upper Basin reservoirs
forecast for September 30, 1982, exceeds the
"602(a) Storage" requirement under any
reasonable range of assumplions which might
be applied to fhose items previously listed,
Therefore. the accumulation of "602(a)
Storage" is not the criterion governing the
release 01 water during the current year.

Mexican Treaty Obligations
Annuai caiendar 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 formula led by the Mex'lcan Section and
presented to the United States Secfion,
International Boundary and Water
Commission, before the beginning of each
calendar year.

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