WSP05262

• File Number: 8146.400
• Description: Pueblo Dam - Reports
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 5/1/1972
• Author: US DoI BoR
• Title: Final Environmental Statement
• Water Supply Pro - Doc Type: EIS

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2. Enlargement of Twin Lakes Reservoir

The alternative of enlarging Twin Lakes, an impoundment located
150 milee northwest of the City of Pueblo, would partially meet
the purposes served by Pueblo Dam and Reservoir. Twin Lakes
could be enlarged to store and regulate irrigation and munici-
pal vater; however, the regulation of municipal and industrial
water to meet peak demands would be difficult. Principal needs
not satiefied by this alternative include (1) flood control
and reduction of sediment on the Arkansas River, (2) storage
of winter flows, and (3) ws.ter-or1ented recreation, hunting and
fishing needs of southeastern Colorado residents.

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Enlargement of Twin Lakes would require acquisition of addi-
tional land, extensive vegetation clearing, relocation of the
town of Twin Lakes, relocation of State Highws.y No. 82 and
various utilities, and construction of a dam spillway and out-
let works. Construction of protective works would be required
on Lake Creek and the Arkansas River downstream from Twin Lakes
Reservoir to contain high summer flows. These high flows are
required to meet irrigation and municipal and industrial demands
in the Arkansas Valley. There would be a greater range of ver-
tical fluctuation of the Twin Lakes water level, and a reduced
head available for ~~. Elbert Pumped-Storage Powerplant, a
major Fryingpan-Arkansas Project power feature to be constructed
on the north shore of Twin Lakes. These fluctuations would
result in major changes in Twin Lakes Reservoir aquatic eco-
system, some of which would be adverse.

There would be irregular flows in the Arkansas River. The
heeviest periodic flows would be in a 100-mile reach of the
river below Twin Lakes Reservoir which could disrupt the river's
fishery and ecosystem.

3. Dam and Reservoir at another Site

Numerous dam sites exist on the Arkansas River above the City
of Pueblo. The proposed site, six miles west of Pueblo, ws.s
selected because optimum benefits could be derived from the
multipurpose functions, many of which were not obtainable at
sites upstream.

Three of the potential damsites are located 5 - 13 miles west
of Pueblo in an area similar to vegetation and topography to
the proposed site. Geologic conditions had considerable bearing
upon the proposed location of the dam. These sites would require
equivalent clearing and relocation of utilities, roads, and
principally the main line of the Denver and Rio Grande Western
Railroad. These sites would have environmental impacts similar
to the Pueblo site.

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