8211

• UCREFRP Catalog Number: 8211
• Author: U.S. Bureau of Reclamation and Fish and Wildlife Service.
• Title: Final Environmental Assessment
• USFW Year: 1997.
• USFW - Doc Type: Providing Fish Passage at the Grand Valley Irrigation Company diversion Dam on the Colorado River.
• Copyright Material: NO

CHAPTER III - AFFECTED ENVIRONMENT AND
ENVIRONMENTAL CONSEQUENCES
General
This chapter discusses resources associated with the Colorado River that could be affected by the
proposed action of providing fish passage at the GVIC Diversion Dam. During preparation of
this EA, input was received from the GVIC, other water users, resource agencies, citizens, and
other parties (see Chapter IV on Consultation and Coordination for further details).
Overview
The project is located in Mesa County, Colorado along the Colorado River. The largest town in
the area is Grand Junction, founded in 1881. The Rio Grande Railroad extended into the area in
1887 and, soon afterward, major irrigation of the valley began. Private irrigation facilities were
first constructed, and in the early 1900's a major Reclamation irrigation project, the Grand Valley
Project, was constructed. Although agriculture remains important in the valley today, a number
of light manufacturing and service industries have influenced the economy. Mesa County has a
population of approximately 110,000. Major occupations in the area include services, retail
stores, government employment, and manufacturing. The upstream limit of consideration in this
report is the town of Rifle in Garfield County. This town has around 5,500 residents involved in
agriculture, mining and services. The project area is semi-arid, although surrounding mesas and
mountains support aspen and spruce-fir forests. The Colorado River in the project area has been
significantly changed due to water uses, infringement by railroads, gravel operations, highways,
and bridges, and by flood control dikes and channelization.
Vegetation and Land Use
The Grand Valley remains primarily an agricultural area, dominated by orchards, vineyards, and
row crops. The Colorado River continues to support narrow strips of riparian vegetation of
cottonwood, willows, and the introduced tamarisk and Russian olive. There is very little riparian
vegetation in the immediate construction impact area. There are several mature cottonwood trees
that would be avoided by the construction activities. Lands in the immediate construction area
are used for irrigation diversion purposes, and a residence with a small farm.
Under the No Action alternative, there would be no change in vegetation or land use. Under the
preferred alternative, temporary disturbance in present land use (on less than 5 acres) would occur
while hauling materials to construct the pools and riffles along the fish passage. Precautions
would be taken to prevent impact to large trees (mostly native cottonwood and introduced
Russian olive) that exist at the sites. Some grasses and forbs would be lost in a 1-2 acre area
through soil compaction, but revegetation efforts should rapidly mitigate this loss. There are no
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