Phoenix, AZ —

A federal court has struck down federal approval of dam operations at Glen Canyon Dam. The Glen Canyon Dam is located on the Colorado River in Arizona just upstream of the Grand Canyon. For now the dam will continue to operate as before but the U.S. Fish & Wildlife Service must reconsider the extent to which the dam’s operations damage the essential habitat in Grand Canyon for a native fish, the endangered humpback chub.

“This is an important ruling for the endangered Colorado River fish and for Grand Canyon,” said Nikolai Lash, Colorado River Program Director at Grand Canyon Trust. “Finally, the federal government is being scolded for ignoring the law and years and years of science to the detriment of Grand Canyon resources.”

The court ruled that Fish and Wildlife Service’s 2008 biological opinion approving dam operations illegally sidesteps the issue of whether current dam operations harm humpback chub critical habitat. 

As the court recognized, “…virtually all of the science contained in the administrative record concludes that MLFF [the current flow regime] releases from the dam destroy or adversely modify nearshore habitat.” Thus the court invalidated FWS’s attempt to approve dam operation because it ignored the past decade of science documenting the destruction of native fish habitat. The court gave federal officials five months to fix the problem.

“Modified Low Fluctuating Flows (MLFF) have been run since 1996 and since then scientists have concluded with near-unanimity that these fluctuating flows damage endangered fish habitat, beaches, archaeological sites, and other key Grand Canyon resources,” said Rick Johnson, Colorado River Science Director for Grand Canyon Trust. 

“The court found that the federal government has refused to take action to protect the native fish habitat downstream of Glen Canyon dam,” said Earthjustice attorney McCrystie Adams. “The court told the federal agencies to rework their dam operating plans to make them consistent with what science tells us is needed to protect the fish. The dam needs to be run in a way that restores the native fish of one of America’s most treasured rivers and landscapes.”

Humpback chub have plied the muddy waters of the Colorado River for four million years. Threats to the survival of humpback chub and their native river ecosystem arise mainly from the many dams on the Colorado River and its tributaries. Glen Canyon dam has tamed the once wild river, initiating a cascade of environmental changes that has already wiped out some native species and has seriously reduced the populations of humpback chub. Sandy beaches, once replenished every year with sediment carried during flood flows, are eroding to bedrock and eliminating native streamside habitats. Water released through the Glen Canyon Dam in uneven pulses tends to destroy the streamside sand bars and banks that help create chub habitat.

“The court simply validated what the scientists have been saying for over thirteen years — dam operations destroy chub habitat in Grand Canyon National Park. Yet Reclamation continues to ignore what has been apparent for years,” said Neil Levine, Grand Canyon Trust’s attorney. “It is time for Reclamation to act responsibly when it comes to protecting one of this Nation’s great natural treasures.”

Read the court order