Flooding of Canyon Called a Success

Like a giant Mixmaster, the artificial flood unleashed in the Grand Canyon last month did what it was designed to do, according to experts--churning up tons of sediment, restoring estuaries and enlarging beaches and wildlife habitat

“The success exceeds the most optimistic hopes of the scientists,” said Secretary of the Interior Bruce Babbitt, who triggered the weeklong gusher that totaled 360,000 acre-feet of rushing water--about the same amount that the city of Los Angeles consumes in seven months.

Joined by environmental scientists from the U.S. Bureau of Reclamation who were in charge of the flood, Babbitt made his remarks during a Washington news conference Thursday.

Canyon beaches and sandbars grew about 30%, according to scientists who observed the flood from various vantage points along the 290-mile stretch of the Colorado River that flows through the Grand Canyon from Glen Canyon Dam to Lake Mead.

While the river rose more than 13 feet, capsizing some rafters who rode the flood tide, scientists said they found little damage to any of the endangered birds, fish or snails that dwell in the canyon.

Initially opposed by hydropower interests that saw it as a waste of water, the huge release represented the first time the federal government has opened the floodgates of one of its own dams in order to repair some of the damage done to river canyons denied their natural flows for many years.

Since the Glen Canyon Dam was completed in 1963 to provide electrical power to six western states, floods that once coursed through the Grand Canyon have been rare. As a result, the sediments and nutrients that buttressed canyon walls and sustained native fish were trapped above the dam in Lake Powell.

Below the dam, a new river emerged, clearer, colder and subject to daily fluctuations by a dam that moved the water up and down, in Babbitt’s words, “like a toilet tank.”

But the river below the dam was not hostile to all living creatures.

A clearer river admitted more light that stimulated algae to grow. The algae supported trout, a nonnative species that thrived after it was introduced. The trout attracted bald eagles, which were uncommon in the canyon before the dam was built. With no spring flooding, vegetation spread that helped extend the range of endangered birds such as the southwestern willow flycatcher.

“The irony of all this is that the modern river corridor had more biodiversity than the historic one,” said Jack Schmidt, an advisor to the Department of Interior.

For Schmidt and other scientists planning the flood, the trick was to come up with a strategy that would help restore some of the river’s past life without jeopardizing the recent additions. It meant generating a flood big enough to restore the murky warm water habitat of the threatened humpback chub but not so powerful that it would wash away food base that the trout depend on or the tamarisk trees where the willow flycatcher nest.

It will take an additional five months for the experts to fully analyze the results, but the evidence so far, Schmidt and others say, is that the experiment worked.

“I came around to the flood idea later than some,” Schmidt said. “But from what I can tell so far, it’s working.”

A spokesman for the federal agency that markets power from the Glen Canyon Dam said it was too soon to put a price tag on the cost of power lost as a result of the water diverted from hydroelectric generation during the flood.

The initial estimate was $2.5 million, but David Sabo of the Colorado River Storage Project said the true cost won’t be known until August, when his office purchases replacement power.

In the meantime, Babbitt is touting the flood as “a very encouraging model for restoration across the American landscape.”

From Florida’s Everglades to California’s Sacramento River Delta, Babbitt said, the Grand Canyon experiment should contribute to efforts to devote more water to environmental restoration.