8089

• UCREFRP Catalog Number: 8089
• Author: U.S. Bureau of Reclamation.
• Title: Final Environmental Assessment Gunnison River Activities, Passageway Around the Redlands Diversion Dam and Interim Agreement to Provide Water for Endangered Fish.
• USFW Year: 1995.
• USFW - Doc Type: Grand Junction, Colorado.
• Copyright Material: NO

at a range of flows, and 300 cfs provides minimum to adequate depths for fish movement. The
300 cfs is necessary to maintain approximately 1 foot -of depth through the critical shallow areas
of the river downstream from the Redlands Diversion Dam. A portion of the same water will
be used to operate the fish passageway. The Service and the State of Colorado will study and
evaluate the effects of the releases on occupied habitat of endangered fish in the Gunnison River.
Recommendations will be made, based on these studies, on development of a long-term water
supply contract. In addition, the effects of the interim water agreement on other water uses in
the basin will be monitored, thus providing important data for use in developing a long-term
contract. Appendix B highlights provisions of the drift agreement.
Three alternatives were considered for how the water agreement will address historic water use
patterns that have developed since the completion of the Aspinall Unit and these are discussed
below. Alternative A, which provides fish flows of 300 cfs from July through October and
historic levels of protection to water users based on water supplies and existing contracts as
discussed below, is the preferred alternative. Under all alternatives, including No Action, water
would be available for sale from the Aspinall Unit for municipal, industrial, irrigation, or other
purposes.
Alternatives
No Action
On any program, the "No Action" alternative exists. Under this alternative, a fish passageway
would not be constructed under the Recovery Program and the interim water agreement would
not be executed. There would be no special effort to maintain a flow of 300 cfs below the
Redlands Diversion Dam at this time, nor would there be special efforts to protect senior water
users downstream of the Aspinall Unit; however, water users would be expected to continue to
utilize Blue Mesa releases dependent on water supplies. The need for a fish passageway would
remain and a passageway could be constructed under other programs. Under No Action, the
endangered fish studies on the Gunnison River would still continue, leading to recommendations
for changing Aspinall Unit operations to protect the fish. However, the absence of a fish
passageway at the Redlands Diversion could impair the Recovery Program's ability to act as the
"reasonable and prudent alternative" to offset the impacts of water use and development, and as
a result both existing and future water use could be adversely affected under the Endangered
Species Act either economically or in ability to use water.
Fish Pa ew
Alternative designs for the fish passageway were also considered, and several different types of
passage structures were appraised. All but one of the alternatives had a vertical slot and orifice
in each baffle. The primary variable of the different alternatives was the location of the
passageway in relation to the diversion dam. Several alternatives were considered which
involved building the passageway over the Redlands Diversion Dam in different locations. These
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