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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DEPLETION OF SURFACE WATER SUPPLIES

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Shpuld the total net depletion in the Upper Basin be limited to
6,200,000 acre-feet per year by the provisions of section Cd) of Article
III of the Colorado River Compact, then the aggregate of such deple-
tions. in Colorado could not exceed 3,100,000 acre-feet per year in
addit~on to reservoir evaporation losses.
Use of the waters of Yampa River in Colorado is limited somewhat
by A#icle XIII of the Upper Colorado River Basin Compact in which
it is stated in part:
The State of Colorado will not cauSe the flow of the Yampa River at the Maybell .
gaging'station to be depleted below an aggregate of 5 million acre-feet for any
period pf 10 consecutive years. * * *
Inasmuch as the total flow of Yampa River at Maybell during the
10 con;secutive years of most deficient runoff of record amounted to
9.4 million acre-feet, this provision will not prevent reasonable use in
Colorllp.o of the waters of this tributary of Colorado River.
Arti~le XIV of this Compact, however, does impose definite limita-
tions on future developments in the basin of San Juan River. The
pertinent provision reads in part as foHows:
The State of Colorado agrees to deliver to the State of New Mexico from the
San Juail River and its tributaries which rise in the State of Colorado a quantity
of water 'which shall be sufficient, together with water originating in the San Juan
Basin in the State of New Mexico, to enable the State of New Mexico to make full
use of th'e water apportioned to the State of New MexiCo by Article III of this
compact,* * *.
The quantity of water allocated to New Mexico by Article III is
substantially 22 percent of that allocated to Colorado. At least 90'
percent of the total flow of San Juan River originates in Colorado and
less thaI! 10 percent in New Mexico. Hence, New Mexico is entitled
to conSUlne one-fifth as much as Colorado of all of the runoff from
the west~rn slope of Colorado. It so happens that the flow of San
Juan River and its tributaries across the boundaries of Colorado into
New Me~ico also equals one-fifth of the total originating in Oolorado.
Therefore, because of this provision in the compact and the physical
situation) it is generally recognized by those who have studied the
problem that there can be little additional depletion in Oolorado of
San Juan: River and its tributaries above the confluence of Animas
River, an~ that expansion of use in the San Juan Basin will be limited
largely by the extent to which the waters of Animas River can be
put to belileficial use.
In briet Oolorado would theoretically be entitled to deplete the
flow of Cplorado River to an aggregate of at least 3,700,000 acre-
feet under, the limitations of the compacts, after allowance for its
share of Qredits for salvage of natural depletions and charges for
reservoir evaporation losses. The practical limit of all permissible
depletions ;in Oolorado may not exceed 3,100,000 acre-feet per year
in addition to its share of reservoir evaporation losses. Increases
from the Present level of depletions to either of these limits will be
subject to; certain legal and physical restrictions upon where the
water is us~d.

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PRESENT DEPLETIONS

During the period of negotiation of the upper Oolorado River Basin
Compact an engineering advisory committee made very thorough
studies of the depletions which had taken place. These are reported

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