Secretary of the Interior Manuel Lujan announced that effective November l, 1991, the Bureau of Reclamation will implement interim operating criteria at Glen Canyon Dam on the Colorado River. The criteria will remain in effect until the Glen Canyon Dam Environmental Impact Statement (GCDEIS) is completed in late 1993 and final criteria for the operation of the facility are approved and implemented
"The interim flows will help ensure the protection of downstream resources in the Grand Canyon until the EIS ls completed in 1993," said Commissioner of Reclamation Dennis B. Underwood. "We will continue to gather information from the ongoing Glen Canyon environmental studies pending completion of the EIS and implementation of a Record of Decision.
"The interim operations limit the daily flow fluctuations to approximately 3 feet or less in the Grand Canyon. - The maximum flow would be limited to 20,000 cubic feet per second (cfs); any release greater than 20.000 cfs will require further evaluation and consultation.
Minimum flows would be 5,000 cfs between 7 pm and 7 am and 8,000 cfs between 7 am and 7 pm. The rate of change in the power plant output would be limited to 2,500 cfs per hour for increasing flows and 1,500 cfs per hour for decreasing flows.
Incorporated in the interim operating criteria are exception criteria which provide for exceeding the flow to respond to emergency situations, system regulation needs, and to reduce the probability of high-cost replacement power purchases. The exception criteria are set forth in an October 21. 1991, Interagency Agreement between the ·Bureau of Reclamation and the Western Area Power Administration.
"The interim operations were tested between August 1 and October 31, 1991, by the Bureau of Reclamation in order to more fully evaluate data from research flows," Underwood said.
On July 27, 1989, Lujan directed the preparation of an environmental impact statement on the effects of the operation of Glen Canyon Dam on the downstream environmental and ecological resources of the Glen Canyon National Recreation Area and Grand Canyon National Park.
Reclamation is the lead agency of a cooperative effort to produce the GCDEIS. The cooperating agencies include the Arizona Game and Fish Department, Bureau of Indian Affairs, Fish and Wildlife Service, Havasupai Indian Tribe, Hopi Tribe, Hualapai Indian Tribe, National Park Service, Navajo Nation, and Western Area Power Administration.
