Wildlife habitat and beaches along the Grand Canyon are flushing away hourly. Congress should take fast action to halt the destruction, says the Sierra Club's southwest regional director.

Rob Smith, now based in Phoenix, was in Salt Lake City visiting friends. He worked for several years in this city. I caught him for an interview and found he is focusing on his new state's most incredible natural resource, the Grand Canyon.Not just his state's, come to think of it, but one of the most amazing places in the world.

Sen. John McCain, R-Ariz., a champion of the Grand Canyon, promises to reintroduce legislation this session of Congress to regulate flows from Glen Canyon Dam, Smith said. The House version is to be sponsored by Rep. George Miller, D-Calif.

Last fall, McCain's bill got bogged down in the "California water wars" that also killed the Central Utah Proj-ect compromise, according to Smith.

"If the legislation is enacted within the first six months of this year, then it will still be in time to influence the postresearch flows, which the secretary of interior says he will adjust to protect the Grand Canyon."

What Smith was referring to is a little complicated. The Bureau of Reclamation heads a research effort that includes the National Park Service, U.S. Fish & Wildlife Service, Arizona Game and Fish Department, U.S. Bureau of Indian Affairs, Western Area Power Administration, and the Hopi, Hualapai, Navajo and Havasupai Indian tribes.

The Glen Canyon Environmental Study is gathering information for an environmental impact statement on the operation of the dam, located at Page, Ariz. The draft impact statement is supposed to be released in 1992.

Starting in June 1990 and continuing until July this year, the study's scientists have released varying volumes of water from the dam, to gauge the effects on Grand Canyon downstream. They study the river's aquatic life, recreation, geology, archaeology, endangered species and other factors affected by the stream flows.

In the past, water roared out of the dam, or trickled, depending on the demand for electrical power. The more demand, the faster the turbines spun. The Colorado River below the dam ripped out beaches, stranded fish and endangered boaters and anglers.

Peaking power requirements cause severe, short-term fluctuations in water level, with the difference in the canyon sometimes reaching 13 feet in a single day. "That has the effect of aggravating erosion on the beaches and preventing a new stability from taking place," he said.

With the dam backing up 80 percent to 85 percent of the sediment the Colorado River used to carry, new beaches don't form after clear-water floods from the dam rip out the old. This hurts the wildlife that depends on streamside vegetation, which floats out to Lake Mead, too.

Congress is so concerned about damage to Grand Canyon National Park that two bills, including McCain's, were introduced to require environmentally sound interim flows after the studies are completed - and they seem likely to pass.

In testimony before Congress, Interior Secretary Manuel Lujan "made a commitment to implement interim flow operation, beginning 90 days after the conclusion of the current research flows," said Mary Ann Facer, public involvement specialist for the environmental impact statement project, speaking from the bureau's regional office in Salt Lake City.

Smith hopes the McCain bill passes soon, because its pro-environment stance would affect Lujan's interim flows. So far, the Interior Department hasn't spelled out what those rules will be.

Under the McCain bill, long-term criteria for operating the dam would highlight protection of the downstream environment. Power production would be incidental to that. Its requirements would kick in this September - assuming it passes.

"There's damage occurring right now," Smith said. "The sooner we fix that, the better off we'll be."

Upstream, in what used to be Glen Canyon and part of Marble Canyon, Lake Powell is at least 60 feet lower this year because of the continuing drought. But even when wet times return, it won't be allowed to fill as high as in 1983, Smith pointed out.

He said that's because, back then, the bureau tried to store as much water as possible in the reservoir. Regulations said Lake Powell should be managed to contend with a flood of the size that can be expected once in four years. That was "a pretty close margin of error," he noted. It was tight enough that when an exceptionally heavy snowmelt hit - as it did in 1983 - the dam couldn't dump water fast enough for safety.

So the bureau backed off, he said. It is now geared to managing a flood of the severity that can be expected once every 20 years. That means Lake Powell won't ever be allowed to rise as high as it did before 1983. The old high-water mark will remain forever, a band of lighter rock on the cliffs and pinnacles wherever Lake Powell extends. It is a permanent bathtub ring.

"This is a constant reminder of how the bureau did not manage Glen Canyon Dam as if the Grand Canyon was downstream," Smith said.