WSP07117

• File Number: 8276.130
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 11/1/1990
• Title: Final Environmental Assessment: Price and Stubb Ditch Improvements - Grand Valley Unit
• Water Supply Pro - Doc Type: EIS

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Chapter II I

AFFECTED ENVIRONMENT AND
ENVIRONMENTAL CONSEQUENCES

Threatened and Endanaered Species

Present Conditions

The endangered Colorado squawfish and humpback chub, and the razorback
sucker, which is proposed for listing, have been documented in the Colorado
River in the Grand Valley. This reach of river supports all life stages
(Fish and Wildlife Service, 1982). The Service has documented spawning
aggregations of radio-tagged Colorado squawfish in the Colorado River
between Palisade and Grand Junction, and larval and young-of-the-year
squawfish have been collected from this reach. Additional information can
be found in Kaeding and Osmundson (1989). The Colorado squawfish is
currently restricted to 25 percent of its historic range.

Field and literature studies indicate that no threatened or endangered
plants occur within the Grand Valley Unit impact area. The endangered
Uinta Basin hookless cactus is found in desert lands south of the valley,
but has not been found in irrigated areas.

The endangered whooping crane migrates through the study area. Theses
cranes are part of an experimental flock that migrate in association with
sandhill cranes. There are at least two active peregrine falcon nests in
the nearby Bookcliffs. Hunting habitat for these birds may include the
Grand Valley area, the Colorado River corridor, and lands to the north of
the Bookcliffs. The bald eagle is a winter resident in the valley using
large cottonwood trees along the river and in the valley for roosting.
Food sources include carrion, waterfowl and fish.

Potential habitat for the endangered black-footed ferret exists in the
desert lands surrounding the irrigated portion of the valley. This species
is not known to exist in the area.

ImDacts

Under the future-without project conditions, the status of endangered
species using the area should not change. Areas along the Colorado River
used by bald eagles may continue to deteriorate as habitat losses due to
developments and increased human recreation occur, and eventually, the
number of bald eagles wintering in the area may decline. Peregrine falcons
may increase in numbers if future State and Federal management programs are
successful. The whooping cranes in the experimental flock are not
reproducing and, therefore, may disappear. The threatened and endangered
Colorado fishes may recover in numbers; however, this cannot be predicted
at this time.

Proposed construction activities along the Price and stubb Ditches would
not adversely affect the Colorado squawfish, humpback chub, and razorback
sucker. Construction would occur during the winter when the ditches are
dry, thus there should be no increases in turbidity downstream. The
proposed project would annually reduce salt-loading contributions from the
Price and Stubb Ditches by some 7,200, and 4,300 tons, respectively.
However, the endangered fishes of the Colorado River exhibit a wide range
of tolerance and would probably not benefit from or be adversely effected
by these reductions in salinity within the river.

The proposed changes to the ditches would reduce seepage from the ditches
and consequently, more water should remain in the irrigation systems than
has historically. This water is commonly called "salvaged" or "saved"

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