Officials question timing of Grand Canyon flush

The Grand Canyon is about to take a bath, and National Park Service officials who oversee the iconic monument are worried.

Federal flood control managers, led by Interior Secretary Dirk Kempthorne, this week plan to unleash millions of cubic feet of water from behind the Glen Canyon Dam to do a “flush” of the huge canyon bottom meant to simulate a springtime flood.

Bureau of Reclamation and U.S. Geological Survey specialists say the 60-hour “blow-out” followed by a series of smaller flows this fall are necessary to blast accumulated sand off the Colorado River bottom, then gradually restore sandy beaches and side pools for endangered species and campers alike.

The flows begin today, and a massive release is set for Wednesday in a media event with Kempthorne.

At its highest volume, 41,500 cubic feet per second of water will burst from tubes at the bottom of the dam, temporarily reducing flows to hydroelectric turbines.

National park officials said that 10 years of research at a cost of $80 million had shown the flooding as planned could wreak irreparable harm to the national park’s ecology and other resources.

Grand Canyon National Park Superintendent Steve Martin said he was given a day to formulate comments to a cursory environmental assessment of the project. In those comments, he wrote that statements by the Bureau of Reclamation used to justify the flows’ timing were “unsubstantiated.” Far from restoring crucial sand banks, the flows could destroy habitat.

Martin said Monday that one flood was not enough and that holding off follow-up floods until after summer peak hours would leave endangered humpback chub fish, sandbars used by river rafting trips and archaeological treasures at the river’s edge diminished “almost to the point of no return.”

Martin suggested the flows served the needs of hydroelectric power producers who need peak production during the summer.

The U.S. Geological Survey acknowledged the floods had been timed in part to maximize power-generation during peak demand periods.