Colorado River Workshop CWCB July 20 2004

• Description: Colorado River Workshop CWCB July 20 2004
• State: CO
• Date: 7/20/2004
• Title: Colorado River Workshop CWCB July 20 2004
• Water Supply Pro - Doc Type: Meeting

Article IV
In the event curtailment of use of water by the states of the upper division at
any time shall become necessary in order that the flow at Lee ferry shall not be
depleted below that required by article lII of the Colorado river compact, the
extent of curtailment by each state of the consumptive use of water
apportioned to it by article III of this compact shall be in such quantities and at
such times as shall be determined by the commission upon the application
of the following principles:
(b) If any state or states of the upper division, in the ten years immediately
preceding the water year in which curtailment is necessary, shall have
consumptively used more water than it was or they were, as the case may
be, entitled to use under the apportionment made by article III of this
compact, such state or states shall be required to supply at Lee ferry a
quantity of water equal to its, or the aggregate of their, overdraft or the
proportionate part of such overdraft, as may be necessary to assure
compliance with article III of the Colorado river compact, before demand is
made on any other state of the upper division:
Article VI
The commission shall determine the quantity of
the consumptive use of water, which use is
apportioned by article III hereof, for the upper
basin and for each state of the upper basin by the
inflow - outflow method in terms of man-made
depletions of the virgin flow at Lee ferry, unless
the commission, by unanimous action, shall adopt
a different method of determination.
1945 Treaty with Mexico
Allots Mexico a "guaranteed annual
quantity" of 1.5 MAF.
In a surplus, may be increased to 1.7 MAF.
In an extraordinary drought, may be
reduced in the same proportion as uses
within the U.S. are reduced.
IV(c) Except as provided in subparagraph (b) of this
article, the extent of curtailment by each state of the upper
division of the consumptive use of water apportioned to it
by article 1II of this compact shall be such as to result in
the delivery at Lee ferry of a quantity of water which bears
the same relation to the total required curtailment of use
by the states of the upper division as the consumptive use
of the upper Colorado river system water which was made
by each such state during the water year immediately
preceding the year in which the curtailment becomes
necessary bears to the total consumptive use of such
water in the states of the upper division during the same
water year; provided, that in determining such relation
the uses of water under rights perfected prior to
November 24,1922, shall be excluded.
Lower Basin Apportionment
• Resolved in Arizona v. California.
• Divides "all the water in the mainstream below Lee
Ferry."
• Apportionments of 4.4 MAFY to California, 2.8 MAFY
to Arizona, and .3 MAFY to Nevada.
• Surpluses and shortages to be decided by Secretary of
Interior. Surplus divided 50% to California, 46% to
Arizona, and 4% to Nevada. Division of shortages up to
Secretary.
1956 Colorado River Storage Project Act
Provides for construction of four major "storage
units:" Lake Powell (24.322 MAF live capacity);
Flaming Gorge (3.75MAF live capacity); Navajo
(1.696 MAF live capacity); and Aspinall (.829
MAF live capacity).
One of the primary purposes of these projects is to
assist the Upper Basin states in using their
compact apportionments (by assuring that
deliveries to the Lower Basin can be met).
Revenues from power from the storage units go to
the Upper Basin fund.
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