WSP10614

• File Number: 8503.400.B
• Description: Costilla Creek/Rio Grande Basin
• Basin: Rio Grande
• Water Division: 3
• Date: 9/1/1965
• Title: Reconnaissance Report on Costilla Project - Colorado - New Mexico
• Water Supply Pro - Doc Type: Report/Study

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SYNOPSIS

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The Costilla Project consists of a collection of private
irrigation developments straddling the Colorado-New Mexico border on
the basin plain that is the southern extension of the San Luis Valley
Basin. Based on the sources of water supply, the project land~_ are
divided into the area served from Costilla Creek only and having
storage water rights and the area served from both Costilla and
Culebra Creeks.

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Flows of Costilla Creek are characterized by high periods
of runoff during the spring lll1OW1Ilelt season and low flows during the
summer. Because of the pervious condition of the upper part of
existing Costilla Dam, the State Engineer ha,s restricted permanent
storage in Costilla Reservoir, on upper CostilJ.a_Creek, to 10,900
acre-feet compared to its design capacit:Jf of 15,740 acre-feet.
However, temporary storage is allowed above restricted storage when
conditions permit. The resulting inadequate capacity has led to
an inade'quate supply of water to meet irrigation demands in the later
part of the irrigation season. Only some 3,000 acres are irrigated
in this area at the present time.

The lands served by both Costilla and Culebra Creeks lie
in the area designated as the Eastdale area. This area has a diver-
sion right to about 1,000 acre-feet of water annually from Costilla
Creek and a diversion right from Culebra Creek during the off-
irrigation season. These waters are stored in Eastdale Reservoir
No.1 to serve the area. However, seepage losses in the feeder
system and East dale Reservoir No. 1 and limitations imposed on the
reservoir due :to the deterioration of the protective facing of the
dam have resulted in inadequate regulation and an inadequate supply
of water to meet irrigation demands. About 550 acres are presently
irrigated from this system.

Reconnaissance investigations indicate a potential exists
for making available, through regulation and rehabilita_t.:lgn of the
present diversion and distribution system, a water supply sufficient
to increasel;he -area served- and to develop recreation and fish and
wildlife resources. The potential plan would include ~:tt;~ticm
and modification of Costilla Dam and Reservoir to a controlled capacity
0:L:t.8,300.acre-feet; construction of Amalia Dam and Reservoir on
_CostillR r.~~ith a controlled capacity of 11,700 acre-feet; con-
struction of basic recreation facilities at Amalia Reservoir; rehabil-
itation of Eastdale Dam ,No.1; replacement of Cerro diversion dam;
a~d reconstruction, rehabilitation, and extension of existing canals
and laterals to serve 10,023 acres of irrigable lands, 4,726 acres
of which are in Colorado and 5,297 acres in New Mexico. Storage
allocations in the reservoirs would be as follows:

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