In 1994 the Fish and Wildlife Service (FWS) recommended that Glen Canyon Dam be operated in a manner more consistent with the Colorado River's natural flow regime in order to protect native fish in Grand Canyon. The Bureau of Reclamation (BuRec) ignored these recommendations and implemented an operating regime that would provide greater benefits for hydroelectric power production. Now, in a new report released on September 30, 2002, FWS in association with Northern Arizona University again recommends the critical need for dam operators to heed FWS’ 1994 recommendations.
Titled Monitoring and Research: The Aquatic Food Base in the Colorado River, Arizona During 1991-2001 the 225-page report stated, "We recommend a decade of the Seasonally Adjusted Steady Flow alternative, with spring beach building flows as climate permits....We feel these flows in combination with alien fish suppression and thermal modification of GCD (Glen Canyon Dam) could make Grand Canyon a sanctuary for native fishes of the Colorado River basin."
BuRec claimed that its preferred operating plan, known as Modified Low Fluctuating Flows, would potentially generate a major increase in the Canyon's aquatic food base, but according to the report, this has not happened and, in fact, the food base is very unstable. "The food base responds negatively to peaking hydropower flows and therefore, this same response applies to native fish and their habitat."
With native humpback chub populations down 75 percent during the study period, it's quite clear that BuRec's efforts are failing. But despite this science-based validation of FWS's 1994 recommendations, no immediate actions by BuRec are being contemplated, just more experiments.
