FLOOD01223

• County: Statewide
• Community: State of Colorado
• Stream Name: South Platte
• Title: Upper Platte River Basin Study 1979-83
• Date: 1/1/1979
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

the states annually, with up to 15,000 acre-feet available for use in
Wyoming below Guernsey Dam and up to 25,000 acre-feet available for use
in western Nebraska.

In 1911, the State of Wyomi ng brought suit in the U. S. Supreme Court
against the State of Colorado and two Colorado corporations to prevent a
proposed diversion from the natural basin of the waters of the Laramie
River. The original decree was entered in 1922. That decree was an
injunction limiting a specific transmountain diversion of water, without
prejudice to certain other transmountain diversions in Colorado or to
certain diversions for the irrigation of the meadowland within the
Laramie River Basin in Colorado. The decree was amended and modified
in 1922, in 1932, in 1936, and in 1940. The modified decree allows
diversions in Colorado in the aggregate of 39,750 acre-feet. Wyoming
receives the remaining flow of the Laramie River and its Colorado
tributaries. The decree excludes Sand Creek, which is only nominally a
tributary of the Laramie River. By 1957, of the 39,750 acre-feet
allocated to Colorado, 19,875 acre-feet were being diverted out of the
basin. The remaining uses were within the basin on meadowl ands in
Colorado.

In the 1950's Colorado indicated a desire to divert more of this
remaining 19,875 acre-feet for uses in other parts of Colorado. Wyoming
contended that under the law of prior appropriation, the place of use of
water could not be changed to the detriment of other appropriators from
the stream. To allow any additional out-of-basin diversion in Colorado
would irreparably harm those in Wyoming who had developed a dependency
upon the return flows of this meadowland irrigation. When suit was
threatened, the States of Colorado and Wyoming met and agreed to file a
joint motion with the U.S. Supreme Court, requesting the Court to
approve a stipulation vacating the previous decrees and to substitute a
new decree which provided that users in Colorado be limited to annual
diversions of 49,375 acre-feet from the Laramie River. Users in Wyoming
would then be entitled to divert the remaining flow of the Laramie River
and its tributaries. Colorado was also enjoined from diverting more
than 19,875 acre-feet of this 49,375 acre-feet from the basin for use in
other parts of Colorado. The remaining 29,500 acre-feet of water
allocated to Colorado was to be used within the basin, and not more than
18,000 acre-feet was to be diverted in any year after July 31.

The South Platte Interstate Compact signed in 1923 apportions the water
of the South Platte River between the States of Colorado and Nebraska.
The principal provisions of this compact pertinent to this study may be
summarized as follows:

(1) The stream gaging station near Julesburg, Colorado, is designated
as the Interstate Station. This is the location at which water flowing
into Nebraska is measured.

(2) Between October 15 of any year and April 1 of the succeeding year,
Colorado has the full use of the water of the South Platte River within
its boundaries, except as described below.

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