9476

• UCREFRP Catalog Number: 9476
• Author: Colorado Foundation for Water Education.
• Title: Citizen's Guide to Colorado Water Law.
• USFW Year: 2003.
• USFW - Doc Type: \
• Copyright Material: NO

Interstate and Federal Law
Colorado River Compact of 1922
The Colorado River Compact of 1922
divides the water of the Colorado River
between what are known as the upper and
lower basin states. The lower basin states
are comprised of Arizona, California, and
Nevada, and those parts of New Mexico
and Utah below Lee Ferry, Arizona.. The
upper basin states include Colorado, New
Mexico, Utah, and Wyoming and that part
of Arizona above Lee Ferry.
This compact allocates 75 million acre-
feet of water for consumptive use averaged
over a 10-year period, for the Lower
Colorado River Basin. The remainder is for
use by the upper basin states. Lake Powell,
located immediately upstream of Lee Ferry;
is managed to deliver some 7.5 maf annu-
ally to the lower basin states, plus a certain
amount necessary to meet Mexican treaty
obligations.
Arkansas River Compact of 1948
This compact apportions the waters
of the Arkansas River between Colorado
(60 percent) and Kansas (40 percent)
based on the inflow to John Martin
Reservoir during the winter storage sea-
son (December 1 to March 31). This
water in storage can be released at the
demand of either state after April 1.
Colorado and Kansas have often been
in litigation before the U.S. Supreme
Court over Arkansas River water since the
early twentieth century. In 1995, the U.S.
Supreme Court Eound that Colorado had
depleted the flow of the Arkansas River at
the state line in violation of the compact.
Irrigation wells installed after execution of
the compact caused these depletions. The
states are now litigating the nature and
extent of the injury to Kansas., and
Colorado's method of repayment, before a
U.S. Supreme Court Special Master. In
response to an order of the Special Master,
the Colorado State Engineer has devel-
oped well administration rules to bring
Colorado into compliance with the com-
pact (see 37-69-101 to 37-69-106 C.R.S.).
Upper Colorado River Basin Compact of 1948
This compact distributes the consumptive use of Colorado River water
among the upper basin states. Subject to interpretation of the compacts and
other laws, as well as the amount of water available in the river, Colorado's con-
sumptive use rights for Colorado River water can vary. The following calculation
is a way of viewing how the ten-year running average 75 million. acre-feet deliv-
ery reduirement to the lower basin might translate into water available for con-
sumptive use by the upper basin states:
Total Water Production in the Upper• Basin.
minus the amount remaining to be delivered to the: lower basin under the
current 1U-year running average
minus 750,000 acre-feet (if the upper basin must bear one-half of the
Mexican Treaty delivery, a disputed point)
equals Total Available to the Upper Basin
naiztus 50,000 acre-feet to Arizona (above Lee Ferry)
Of the remainder, the upper basin states receive:
Colorado = 51.15°io
Utah = 23%
Wyoming = 14%
New Mexico = 1125%
For water planning purposes, the Colorado Water Conservation Board
assumes that there is up to 400,000 additional acre-feet of Colorado River water
remaining Eor consumptive use that Colorado can develop under the 1922 and
1948 Colorado River compacts.
C I T I Z E N S G U I D E T O C O L O R A D O ~/ A T E R LAW ~ 2 3
Colorado is a source state - no rnajor rivers flow into Colorado. This reap shows
the relative, historical average annual stream flows leaving Colorado.