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

Use Plan include protecting, conserving, and efficiently managing the county's public lands;
and to encourage the preservation of sustainable ecosystems. Recovery Program efforts are
made using an ecosystem approach that parallels the Mesa County land use plan.
- There were several concerns related to the potential for piecemealing compliance with NEPA
since additional passageways may be needed upstream at the Price-Stubb Dam and Government
Highline Canal Diversion. This EA describes the proposed construction of an experimental riffle
and pool fish passage at the GVIC Diversion. In this EA it is recognized that future fish
passageways may be constructed. At this time, however, the need has not been fully agreed upon
and plans and designs are not in sufficient detail to analyze. This present EA recognizes some
of the concerns that could be associated with future passageways and environmental
commitments for these future possibilities are suggested. Site specific EA 's will be prepared for
any upstream passageways if plans proceed.
- One comment was received expressing concern that high selenium levels in the river may
prevent recovery of the fish. Selenium, a nonmetallic element, is essential in normal animal
nutrition but levels not far above required levels in diets may produce toxic effects (Lemly and
Smith 1987). The Grand Valley is a major source of selenium loading to the Colorado River.
Ongoing studies have been designed to determine selenium toxicity to the endangered fish; this
work is not complete, but selenium concentrations may be adversely affecting the fish. The riffle
and pool design described in this EA is experimental, but may lead to additional passageways
that would allow fish to move further upstream where selenium levels are lower and,
theoretically, less of a potential problem.
- Water users requested a commitment from the Recovery Program that stocking captive-reared
endangered fish will not be impeded by construction of a passageway. The Recovery Program
has agreed to use stocking as a management tool in recovery efforts. Ongoing stocking
experiments are being conducted and these studies will determine the relationship between size
of captive-reared endangered fish at the time of stocking and survival. Propagation facilities
(hatcheries) continue to be constructed, and stocking of captive-reared endangered fishes will
continue.
-One comment expressed concern, that during certain low flow periods, water intended for use
through the fish passage would be lost through the Orchard Mesa check canal, and a new control
gate may be needed in the check canal to prevent this loss. This would be a concern at some
specific flow levels in the Colorado River. When the check canal is open and water is not being
"checked" back upstream, some water will flow downstream through the canal bypassing the
fish passage. At some low river flows, this may cause the fish passage to become unusable.
However, it is acceptable if the fish passage is not useable 100 percent of the time. If the
frequency of these flow conditions and the ability to use the passage becomes unacceptable, it
may become necessary to control the bypass water. An existing check canal structure with stop
logs could be used to control the bypass flows, but it is cumbersome to use. Frequent cycles of
installing and removing the stop logs would be labor intensive. Since it is the intent of the
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