WSP06981

• File Number: 8276.110
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/16/1978
• Title: Negative Determination of Environmental Impact: Stage One of the Grand Valley Unit - Colorado River Basin Salinity Control Project
• Water Supply Pro - Doc Type: EIS

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C. ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTION

1. Physical Setting

The Stage One development would have only minor impacts On the local
setting, as construction would essentially be confined to the improvement
of existing structures within present rights-of-way and easements. The
basically rural, agricultural setting of the Stage One area and the desert
landscape of the area to the north would be temporarily disrupted by traf-
fic, noise, and dust from construction activities. The Government Highline
Canal would be altered by the replacement of the present irregular channel
with a very regular concrete-lined channel and the addition of safety fence.
The existing open earth laterals would be replaced with buried pipe, and
the ground surface would be reshaped to conform with the surrounding lands.
Existing vegetation along 41 miles of canal and lateral routes would be
disturbed by construction activities, and vegetation control during future
operations would limit regrowth. About 90 acres of sparse desert vegeta-
tion would be temporarily cleared during cross-drainage improvements and
materials excavation. The affected areas would be shaped and reseeded
with drought-resistant species such as saltbush, western wheatgrass,
Indian ricegrass, wild rye, sand dropseed, winter fat, Galleta grass,
and Nuttalls saltbush, but recovery would be slow due to the arid climate
of the area.

The following table summarizes habitat changes due to construction
and operation of Stage One.

Changes in wildlife habitat in Stage One area
Present
area
(acres)
l,3s0

Habitat type
Saltbush

Effect of development
No change in vegetative cover; 90
acres committed to cross-drainage
program or borrow areaS.
Ten acres cleared in borrow area;
ls acres of marsh may change to
greasewood.
No change.
Reduced water supply may reduce
extent or quality.
Fifteen acres dried up; remainder
may be affected by changes in
water supply.
Quality of habitat for wildlife
reduced 35 to 50 percent.

Grease\vood

380

Tamarisk
Cottonwood woodland

135
lO

Marsh

100

Agricultural

7,820

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