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On Wednesday the federal government returned the Colorado River to some of its former glory. The Bureau of Reclamation unleashed a two and a half day artificial flood through the Grand Canyon to rebuild beaches and create wildlife habitat. But environmentalists, and even some federal officials, say the experiment doesn't go far enough. Daniel Kraker from Arizona Public Radio reports.



There isn't a more spectacular backdrop for a press conference than the bottom of Glen Canyon Dam. Sheer, red sandstone cliffs tower skyward on both sides of the river. The dam curves elegantly, holding Lake Powell at bay hundreds of feet overhead.

Today we're here to set the river free once again.

Interior Secretary Dirk Kempthorne is here to pull the lever that will open two jet tubes sort of like giant spigots at the bottom of the dam.

The water will be released at a rate that would fill the Empire State building within 20 minutes 300,000 gallons of water per second.

The water shoots out of the giant valves with incredible power. Within seconds the placid river below the dam is transformed into churning whitewater.

This high flow experiment is designed to mimic the flow of the Colorado River before it was tamed, when spring runoff from the Rockies would cascade through the Canyon in muddy torrents. Those floods left behind miles of sandy beaches; beaches that have slowly disappeared since the dam was built in the early 1960s.

John Hammill is with the US Geological Survey, the agency charged with studying the effects of the experiment.

The main goal of this is to see whether or not we can stop the erosion of sediment in the canyon. Sediment and the sand bars are a fundamental element of this ecosystem.

Hammill says it takes these high flows to pick up sand at the bottom of the river channel, and recreate beaches that support plants, wildlife and endangered fish. This is the third flush in the past 12 years, and by now everyone agrees they do help restore the Grand Canyon's fragile ecosystem. The controversy is over what should happen after the dam's jet tubes are cranked shut on Friday. Nikolai Lash is with the environmental group Grand Canyon Trust.

The scientists tell us that these flows need to be done every year, if you don't do them every year, you quickly lose the benefits that attend a flow like this, they literally get washed downstream to Lake Mead.

The Bureau of Reclamation is not planning another high flow in the next five years. The experiments are expensive this one will cost about three million dollars in lost hydropower revenue. Critics like Lash say the government is trading off the health of Grand Canyon for electricity generation. And he's joined, strangely enough, by Grand Canyon National Park superintendent Steve Martin.

We need to be bold, and we need to get back a true equity between power, water and preservation, and of all places, let's do that at Grand Canyon, let's show that we can provide for water and power and protect this phenomenal park.

But Bob Johnson, commissioner of the Bureau of Reclamation, says his agency can't be bold until he sees more studies. He says this experiment is another step in finding a delicate balance between preserving the Grand Canyon downstream, while also generating clean electricity and storing water for the booming southwest.

We're gathering more science, and if the science tells us that doing more of these makes sense, then we'll make those decisions when we get that information.

But the Grand Canyon's Steve Martin says the science is already clear, and we can't afford to do still more research while the last remnants of this incredible natural system are eroded away.

For Arizona Public Radio, I'm Daniel Kraker

