WSP11823

• File Number: 8281.400
• Description: Colorado River Studies and Investigations -- Colorado River Depletion Projections
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/25/1955
• Title: Report on Depletion of Surface Water Supplied of Colorado West of Continental Divide
• Water Supply Pro - Doc Type: Report/Study

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J)EPLETION OF SURFACE WATER SUPPLIES

in d,etail inyolume III .of, the official record of Upper Oolorado River
Basm Oompact OommIssIOn. In the case of Oolorado, it was found
that its contribution to the historic flow of Oolorado River and its
tributaries at the boundaries of the State had averaged 10,408,400
acre-feet per year for the period from 1914 to 1945 and that its con-
tribution to the virgin flow at the same points would have averaged
11,451,200 acre-feet per year. The historical depletion within Oolorado
was thus found to have been 1,042,800 acre-feet, per year, which was
the difference between computed depletions at sites of use aggregating
1,062,753 acre-feet and about 20,000 acre-feet of salvaged natural
losses.
. This total value was the summation of depletions in 30 subareas
caused by irrigation of different types of crops, by the consumption of
water on seeped lands, and by transmountain diversions, reservoir
losses, and other uses. It has been deemed advisable for the purposes
of this report to group such depletions in five geographic divisions;
to wit: '.
. 1. All of the northwesterly portion of Oolorado within the drainage
. basin 'of Green River, including Y ampaRiver and White River, its
principal tributaries. The reason for grouping these is that some of
. tbe potential irrigation projects involve diversions out of Yampa
Rivedor irrigation in part oflands in the White River Basin or diver-
sions from White River for irrigation of lands in the YampaRiver
Basin. The other tributaries of Green River are too insignificant to .
warran t segregation. '.
. 2. All of the drainage basin of Oolorado River from its headwaters "
to the westerly boundary of the State, exclusive of the portion drl;tined } <
by Gunnison River. Gunnison River is excluded because little use
qan be made in Oolorado of water from this source hy diversions below
its confluence with Oolorado River.
. 3. All of the Gunnison River Basin.
, 4. .The areas drained by Dolores River and by tributaries of San
~uanRiver which enter the latter below Shiprock. This portion. of
the San Juan. Basin is grouped with the Dolores Basin because 'of
tt:ansfers of water from Dolores River for the irrigation of llj,nds in
San Juan Basin, and because the westerly tributaries of San Juan.
R~ver are not physically available for use in New Mexico.
5. San Juan River Basin in Oolorado a.bove Shiprock, including
LIiPlata River, Animas River, Florida River, and Los Pinos River.
. . lJ'he average depletion in each of these subdivisions of the drainage
haiJinof Oolorado River during the 32 years ending September 30,
19405, was found by the Engineering Advisory Oommittee to have
helln:

Acre-feet
perf/ear
Green River Basin____ ___ __ _ ___ _ _ _. _ _ ____ __ __ _n__ __ _ ___ __ __ _ _ _ 99, 123
ColQrado River, main stem_ _ _ c-- -: --- - _ -- - - - - - -: -- --"c _ _ ___ ____ 385,939
Gunnison River Basin_________.________._______________________ 351,613
Dol6res River Basin and lowei' tributaries of San Juan Rivern____n_ 120,367
San 'Juan River above Shiprock_____.______________._________n_ 105,711

Total depletion at sites of use_______,__________________~__ 1,062,753

. Sihce these data were assembled for use in the negotiation of the
upper Colorado River Basin compact, there has been some expans'ion

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