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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18

DEPI,ETION OF SURFACE WATER SU-PPLIES

;south of Yampa River and in Axial Valley between Yampa River and
'White River. The remainder of the irrigable land in Yampa River
Basin is scattered along tributary streams and near the headwaters.
Almost 60 percent of the land possible of irrigation in White River
Basin lies in upland valleys north of White River and within 40
miles of the State line. Most of the remainder is adjacent to presently
hTigated lands in the vicinity of Meeker.
. These lands in northwestern Colorado are generally between
6,000 and 7,500 feet above sea level and the growing season would
be relatively short. Large storage reservoirs would be needed for
any material expansion of the presently irrigated area, particularly
ll,S to lands served from Little Snake River. Each of the major proj-
ei:lts that might be built would also require long and expensive canals to
reach the lands and the costs of distribution facilities would be larger
than for existing irrigation projects.
i It is evident that conditions are no more favorable to expansion
of irrigation agriculture in Green River Basin than elsewhere on the
western slope. In the case of the main stem of Colorado River, the
total area of new land included within the 20 projects studied amounted
to less than 45 percent of the total area in the basin found to be
irl'igable but not now under irrigation. 'In Gunnison River Basin,
a little more' than 40 percent of all irrigable land not now irrigated
w~s included in the 18 projects considered as possibly feasible.
~f the relationship between the maximum subsidy per acre of
new land and the corresponding area of new land included in irrigation
projects in the Colorado River and Gunnison River Basins be applied
to ,Green River Basin, and if such subsidies were to be limited to
$6QO per acre, only one-third of the total irrigable land not now
irrigated could be supplied with water; if such subsidies were limited
to $400 per acre, the proportion would be only one-seventh of the
total area of land found to be irrigable. The stream depletion for
varying maximum subsidies would then be as follows;

Relation of subsidies to depletion, Green Rioer Basin

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Total area. of
new land or
equi\'alent
...,-

Resulting do-
pletion of
streamflow

MBXiolUID subsidy per acre of new land or equivalent:
$200 _ ___h.__.. _._ __ _. ____.. _. _h _ _. ___ __ _.h ____. _ _. _ ___.. _ __ _ h ____
$400__..__.__.__.____._______..______._.._.________.__.__.._.____.._.
$600_ _.. __.. _ ___ __ ___ _ .__. ___h___h ___.. _ __ _ __ ___ _. _ ____ ___' ____ _ ___
$800 .... __. _ h___no_ _ _______ __n _. _ ____ _ _ ___ _ ____ __ __. _ _ __ _ _ _ __ _ _ ___
$1,000____ ___h ___ h__ _ _____ _n ___. m'h _ ___h __._ _____ ______ h_ _ ____

Acre-feet per
year
21,000
136.000
312,000
395, 000
440,000

Acres
15,000
97,000
. 223, 000
282,000
314,000

In' general, there is no likelihood that the required subsidies to
irrigation would be less in the Green River Basin than for the projects
incluiling more land elsewhere on thewestern slope. On the contrary,
it probably would be disclosed by detailed investigations that even
greater subsidies would be required.

Probable limit oj depletions
No definite limit can be placed upon the depletion of the flow of
Colorado River at Lee Ferry which may result from expansion of
irrigation agriculture on the western slope. The area of land which

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