WSP10141

• File Number: 8542
• Description: Conejos Division - Platoro
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 4/1/1947
• Title: Supplemental Report - Conejos Division - San Luis Valley Project - Project report No. 5-101-1
• Water Supply Pro - Doc Type: Report/Study

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as other realty. . Many of these companies maintaining a heading in the river
and a canal and distribution system to serve their lands operate on a basis
of stock ownership in the aggregate water supply, each individual member
water user's interest being represented by stock mvnership which entitles
him to a proportionate ryart of the company's water supply delivered through
its canal system.

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Under the constitution and laws of the state of Colorado, a direct
diversion right may not be stored and thus converted to a storage right to
the injury of junior water right ovmers, and direct flow rights which are
not used by a senior appropriator are delivered to junior appropriators as
a matter of right by the state Water Administrative officials. The law does
not prevent direct flow appropriators to store and regulate the delivery of
such rights in a manner agreeable to all of such appropriators, and in as
much as a large proportion of the direct diversion appropriations on the
Conejos River and its tributaries are within the proposed contracting
. entity, namely, the Conejos Water Conservancy District, it is proposed to
work out among the beneficial users of water rights within the district, a
satisfactory plan of distribution of the regulated water supply, proposed
to be stored in the Platora Reservoir. Such an agreeuent will not adversely
affect the few appropriators on the stream above and below the district.

The district proposes to make the necessary filings with the State
Engineer under the laws of Colorado to effect a right to store and regul2tr.,
the aggregate of its direct flow rights in the Flqtora Reservoir, and it a$o
proposes to file and prosecute to satisf~ctory degree an action adjudicating
the rights made under such application to, and permit by, the State Engineez"
In summary the contracting entity proposes to assume full responsibility fur
the storage and regulation of the aggregate of direct diversion rights wi thin
the district as between the different priorities of water use within the '
district, as well as between those within the district and such as are nct
in the district.

Origin of Stream fl0w

The major part of all streamflow in .the Conejos River Basin is pro-
duced from snow melt in the high mountains. In the Valley proper, runoff
from either snow melt or rainfall is negligible.

The drainage area of 285 square miles above the Nogote gage, at the
head of the project area, is a prolific water prOducer, and has produced
an average of 256,000 acre-feet annually. The drainage area above the
Platoro Dam Site is more productive than that abole ~ogote, yielding an
estimated average annual runoff of 85,000 acre-feet from 40 square mileb
of drainage area. The San Antonio River and its chief tributary, the Los
Pinos River, contritute to the head of the irrigated area on these streams
an average a~~ual supply of almost 110,000 acre-feet, a large part of whic~
can be utilized by the project lands.

The untimely natural runoff is apparent when compared to the irriga-
tion needs of the district lands. Approxi .1ately 78 percent of the natu!'a I
runoff occurs prior to July first, yet 52 percent of the ideal irrigation
demand remains to be supplied. The need for storage to provide late seaso~

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