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

GVIC irrigation system from additional expenses or any adverse impacts on water rights or water
supplies. The project would provide some local employment, but because of its relatively small
size, there would be no impact to schools, public services, or overall income in the Grand Valley.
Under the No Action alternative, problems associated with a river portage and dangerous
conditions associated with a hydraulic jump (currents caused by the structure) at the dam and
other river conditions near the project area would continue. At higher flows the diversion would
remain boatable. Under the proposed plan, recreational boaters would not be significantly
affected. The rocks on the downstream face of the diversion dam would reduce the severity of
the hydraulic jump downstream of the diversion dam crest along the 400-foot section of the dam
in contact with the fish passage structure. Existing flow patterns along the remainder of the dam
crest downstream of the fish passage would not be significantly changed by construction of the
passage. The "notch" in the diversion described previously may well attract boaters. At low
water, the riprap riffle and pool arrangement might not be passable by all boats; however review
of the design and model tests with experienced rafters, canoeists, and kayakers during the draft
EA review period, indicated that the passageway would probably improve conditions for boaters.
Preliminary designs for the riprap specify a "zigzag" flow path through alternating riffles and
pools which at low water minimizes the slope and thus the flow velocities the fish must
overcome. The riffle and pool arrangement and notch in the dam are not intended to
accommodate boat use, but it is recognized that it would probably be used. Recreationist who
attempt to use the riffle and pools would encounter sharp turns and boulders throughout the
passageway. As flows increase the turns and boulders become submerged. The GVIC diversion
remains a potentially hazardous structure and boats should not attempt to cross it at any location
under any flow condition.
From an aesthetic standpoint, the proposed design would appear very natural in the river corridor
because of the native rock construction material.
Indian Trust Assets
Indian trust assets are defined as legal interests in property held in trust by the United States for
Indian Tribes or individuals, or property that the United States is otherwise charged by law to
protect. No Indian trust assets are known to occur in the project area and therefore no impacts
are projected under the No Action or preferred alternative.
Environmental Justice
Executive Order 12898 established environmental justice as a federal agency priority to ensure
that minority and low-income groups are not disproportionally affected by Federal actions. The
ethnicity of the majority (90 percent) of the residents in the project area is white (Grand Junction
Chamber of Commerce 1997). Other ethnicities of persons in the area include Hispanic (8
percent), and Native Americans, Asians, and blacks, all less than I percent.
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