WSP02261

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1990
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1990 Projected Operations 1991
• Water Supply Pro - Doc Type: Publication

Projected Plan of Operation - Water Year 1991

Detennination of 'ti02(a) Storage"

Section 602(a)(3) of the Colorado Ri"'r Basin Project Act of
September 30, 1968 (Public Law 90-537), stipulates that
Colorado River water, vvhich is not required to be released
under article III(c) and III(d) of the Colorado Ri"'r
Compact, be stored in Upper Basin reserwirs to the e><tent
the Secretary of the Interior (Secretary) finds such storage
necessary to assure compact deli~ries without impairment of
annual consumpti", uses in the Upper Basin.

Article II of the Operating Criteria provides that the annual
plan of operation shan include. 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 determin.tion sh.ll consider all applieable la\\5 and
relevant factors including, but not limited to, the following:
(0) historic streamflo\\5; (b) the most critical period of
record; (c) probabilities of water supply, (d) estiroated future
depletions in the Upper B.sin, including the effects of
recurrence of critical periods of water supply, (e) the "Report
of the Committee on Prob.bilities and Test Studies to the
Task Force on Operating Criteria for the Colorado River,"
dated October 30, 1969, and such .ddition.l studies .s the
Secretarydeemsnecessary; and (t) the necessity to assure that
Upper Basin consumpti~ uses arc not impaired because of
failure to store sufficient 'Water to assure deliveries under
Section 002(.)(1) and (2) of Public Law 90-537.

Taking into consider.tion these relevant factors, the Secretary
has determined that the .cti.... storage in Upper B.sin
reservoirs forecast for September 30, 1991, exceeds the
"OO2(a) Storage" requirement under any reason.ble r.nge of
assumptions which might be .pplied to those items previously
listed. Therefore, the .ccumulation of "602(.) Stor.ge"is not
the criterion go~rning the release of\V3.ter during the current
year.

Mexican Treaty Obllgations

Annual calendar year schedules ofmonthlydc.li~ries of water
in the limitrophe section of the Colorado Ri",r, .llotted in
accordance with the Mexican Water Treatysigned in 1944,are
forrnulated by the Mexic.n Section .nd presented to the
United St.tes Section, lntern.tional Boundary .nd Water
Cornrnission (Cornrnission), before the beginning of each
c.lendar ye.r. Upon 30 d.ys .dvance notice to the
United St.tes Section, Mexico h.s the right to rnodify, within
the tot.l schedule, any rnonthly qu.ntity prescribed by the
schedule by not more than 20 percent.

Based on the current water supply conditions, the
United St.tes will rnake scheduled deli"'ries of 1,500,000
acre-feet of Color. do Ri"'r water to the Republic of Mexico
in c.lendar year 199I. Representati",s of the Republic of
Mexico will be kept informed of operating schedules through
the United St.tes Section ofthe Commission.

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