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Mussel beach: Lake Powell has 'trillions and trillions of these things'

GLEN CANYON NATIONAL RECREATION AREA — As recreationists flock to Lake Powell this summer — as they always do — many of them are going to be shocked.

The shells of tiny quagga mussels — much like clamshells — are now so visible and so dense on rock surfaces that tourists will have trouble avoiding them.

They're usually out of sight; the invasion of quagga mussels has been building underwater for six years. But now, with water levels low, dead and dying shells are out of the water and clinging to rocks in astronomical numbers.

"Last spring was the first time that we noticed mussels in the north end of the lake at all," said Andre Delgalvis, of Grand Junction, Colorado, as he motored out of the harbor at Bullfrog Marina, the major boating facility on the northern portion of the vast man-made reservoir. The veteran boater pointed out that Lake Powell's famous white "bathtub ring" isn't so white this year.

"All this dark material that you're seeing on the side of the wall, it goes up maybe 15, 20 feet," Delgavis said. "These are all mussels that have just appeared within the last year."

He motored past mile after mile of tiny shells — the size of a fingernail or smaller — covering vast stretches of exposed rock.

"It's just mind-boggling that there could be such an outbreak and so many of these," Delgalvis said. "I mean, we're talking trillions and trillions of these things."

Officials of the National Park Service are quick to point out that it's not a new outbreak. It's actually more like the lowering of a curtain.

"In the years past, the water has been at a level that the average boater that comes and goes has not been able to see the mussels," said Colleen Allen, aquatic invasive species coordinator of the NPS-administered Glen Canyon National Recreation Area.

Last year the lake level went up vertically about 28 feet, allowing mussels to climb higher on the reservoir's rock walls. Now — after one of the driest winters on record — the lake is low again, leaving uncountable trillions, possibly quadrillions, of shells. Allen calls it "an opportunity to help folks to really understand what's below the water level."

Many boat owners already understand it. When boats are left in the water for long periods, their hulls, propellers and outboard motors become covered with shells. The mussels, which are native to the Black Sea region of Eurasia, are generally carried lake-to-lake on somebody's boat. Indeed, quagga mussels and their zebra mussel cousins are believed to have entered North America when a ship from the Black Sea entered the Great Lakes and emptied its ballast tanks.

On a smaller scale, that's apparently how quagga mussels got into Lake Powell — by hitching a ride on a boat that was hauled by trailer from a previously infested waterway.

"You get the people that don't care enough to wash their boats properly and this is what happens," boat owner Scott Lodder of Kaysville said as he gestured toward Lake Powell.

Federal and state agencies spent years in an aggressive campaign to educate boaters and to inspect and sometimes clean boats before they entered Lake Powell. After losing that battle, the agencies turned their strategy upside-down. Instead of trying to keep quagga mussels out, they're now trying to keep them in so they won't spread to other lakes and rivers. The focus is on boats leaving Lake Powell.

"You want to clean your boat, drain your boat and then let it dry," Allen said, emphasizing the main theme of the ongoing boater-education effort. Some boaters don't need additional persuasion.

"We watched Lake Mead get ruined" by quagga mussles, said Cedar City boat-owner Mike Sherratt. "Our support is 100 percent behind this effort to try and contain it."

At the Glen Canyon Dam, which created Lake Powell by plugging the Colorado River, the impacts from mussels so far are not great; they involve just a bit of extra cleaning.

"It has led to about eight more days worth of work for two people," said Shane Mower of the U.S. Bureau of Reclamation.

But the dam's problems might be just getting started. Quagga shells are turning up in nooks and crannies of the dam, and they've infested parts of the plumbing. A huge underwater control-gate that was recently removed for cleaning had a coat of shells 2 to 3 inches thick.

Next year, to protect the dam's cooling-water pipes and fire-suppression system, the bureau plans to install filters with ultraviolet light to kill the quaggas.

"And that's got a price tag of about $1.8 million," Mower said.

Last year, sampling of the lake suggested the possibility that the infestation might be leveling off in the lower end of the lake. But experts say it's too soon to say if that's a real trend.

With so much of the lake now infested it will take plenty of effort — by government agencies and especially boaters — to keep Lake Powell's mussels from spreading elsewhere.

"Well, a lot of people feel that it's a lost cause," said the Bureau of Reclamation's Robert Radtke. "But, you know, until you quit, the fight isn't over."