The Grand Canyon is one of the Nation’s treasures. The Department of the Interior is proposing a series of experimental actions, some of which involve modifying the operations of Glen Canyon Dam, which is located upstream of the Grand Canyon, to improve the condition of the habitat within the Grand Canyon and the species that have their home in the canyon. This proposed action was deemed necessary by the Glen Canyon Dam Adaptive Management Program because endangered species and sandbars in the Grand Canyon have not responded as well as predicted to past management actions regarding the operation of Glen Canyon Dam. The proposed actions, detailed in the accompanying report, are the product of years of scientific study and would implement the recommendation of an independent advisory committee that has been studying the natural and cultural resources of the Grand Canyon since 1997. The proposed actions presented in this report are multi-faceted and complex, and have been designed to protect both the endangered species and the important beach habitat found in the Grand Canyon.

Since 1996, the non-native trout population in the Grand Canyon has tripled, the endangered humpback chub (HBC) population has declined precipitously, and tributary sediment inputs are not being conserved as expected in the FEIS. These trends are contrary to the expectations of the FEIS and the goals of the adaptive management program. If no actions are taken and current operations continue, these trends are expected to continue.

An experiment consisting of a combination of Glen Canyon Dam releases and mechanical removal of non-native fish is proposed to determine if these proposed actions can reverse current trends. The proposed dam releases are intended to conserve sediment inputs from the Paria River and reduce spawning and recruitment success of non-native trout. Mechanical removal of non-native fish is proposed in order to remove trout who feed on young chubs near the confluence of the Little Colorado River (LCR), which is the only known stream in Grand Canyon where the endangered humpback chub reproduces and survives to adulthood.

The environmental consequences of the Proposed Action are expected to be positive for resources intended to be benefited by the action, though due to the experimental nature of the proposal, there is some uncertainty as to the outcome. The proposed combination of experimental dam releases and non-native fish removal has been developed using knowledge gained in nearly 20 years of research and monitoring of resources in this reach of the Colorado River, first under the Glen Canyon Environmental Studies and now as part of the Adaptive Management Program.

There are public open houses held on October 2, 2002, from 4-8 p.m. at the Radisson Woodlands Hotel, 1175 West Route 66, Flagstaff, Arizona; and on October 3, 2002, from 4-8 p.m. at the Hilton Phoenix Airport Hotel, 2435 South 47th Street, Phoenix, Arizona. Attendees had the opportunity to browse informational stations and interact with scientists on issues regarding sedimentation, native and non-native fish species, cultural resources, recreation and hydropower.

The EA, with the Biological Assessment appendix, is available as a PDF (portable document format) file for viewing online. Viewing and/or printing a PDF file requires Adobe Acrobat Reader, a free program available for downloading. You may also request a paper copy of the report by calling Linda Whetton at 801-524-3880.

Mailing address:
Bureau of Reclamation
Attn: Linda Whetton
125 South State Street
Salt Lake City, Utah 84138-1147