On summer mornings, Al Wachlin puts on his muckiest clothes and pilots a no-name barge up and down the Schuylkill, trawling for weeds.

Wachlin, 77, steers slowly through lime-colored vegetation that motorists and joggers see blanketing the surface, but the salad he's after lives deeper down, a hearty and hairy fighter called the Eurasian water milfoil that's not supposed to be in the river or really anywhere in the United States.

"It's just backbreaking labor," Wachlin said.

Wachlin, a former rower for the University of Pennsylvania and a semiretired real estate investor, has gotten creative trying to keep one of the nation's premier rowing destinations clear of milfoil. The Schuylkill Navy, founded in 1858 to promote rowing on the river, owns a milfoil "mower," which resembles a motorized bear trap. But cutting the stuff just made it grow faster.

So Wachlin now uses a 6-foot steel bar he bought at a hardware store, which volunteers drag across the river bottom.

"We just drop it and the milfoil wraps around the bar," Wachlin said.

The process seems Sisyphean with so many miles of rowing lanes affected, so the Schuylkill Navy is hoping for bigger solutions to the milfoil problem.

"There's a lot of it," said Paul Horvat, commodore of the Schuylkill Navy. "There's acres of it."

Wachlin and Horvat, who rowed for Princeton University, have been on the river for decades and have seen blooms of milfoil in the past. The summer of 1991 was a bad one.

"It's never been this bad, though," Wachlin said.

They blame this summer's harvest on higher temperatures, a mild winter, and not enough rain. They believe global warming and warm-water discharge from the Limerick Generating Station could also play a part.

A flood would help in the short term, both men agree, because a powerful, fast-moving flow would tear the milfoil from the river's bottom and send it down toward the Delaware River.

The long-term solution would be to dredge the Schuylkill to a uniform six feet above the dam, where all the rowing occurs. The Army Corps of Engineers last dredged that stretch of the river in 2000. Its projects are often prioritized by commercial and navigational needs of the waterway.

Above the dam, where there are no shipping lanes, dredging would be more of an ecosystem restoration or recreation project, an Army Corps spokesman said.

Horvat, 57, said that the project would cost an estimated $4.7 million and that the Schuylkill Navy has enlisted the help of U.S. Rep. Robert Brady. In May, Brady said he was working to obtain funding.

Milfoil is native to Europe, Asia, and northern Africa, according to Pennsylvania's Department of Conservation and Natural Resources, which believes it was likely brought to the U.S. between the late 1800s and 1940s by boats or the trade in aquariums. It's now established throughout the country, particularly in large lakes. And apparently, it's here to stay.

"We are not going to get rid of it," said Alfred E. Schuyler, a botanist at the Academy of Natural Sciences of Drexel University.

Everyone agrees the milfoil is a major problem for recreational areas. Thick stands of the drabby-green milfoil foul up engine propellers and change the outcome of races, Wachlin said. Horvat said he couldn't recall a drowning related to milfoil, but said the plant can tip a boat with its long tentacles. It's not easy to swim through.

"If you're in a single, you can flip," Horvat said. "It can catch your oar and off you go. I talked to two guys this week who flipped in the last 10 days."

That happened last month to Matt Morano, 37.

"You get all tangled up in the weeds," said Morano, a former Penn rower. "I had them all twisted up around me. You panic for a moment, but they tear apart pretty easily. Getting back in the boat is the hardest part."

While environmental agencies throughout the country say blankets of milfoil could block out light, crowd out native species, and reduce habitat for fish, Schuyler doesn't believe milfoil is a major problem for the habitat.

"I can empathize with the recreational issues. No one wants to dive in a lake and get tangled up in Eurasian milfoil," he said.

But the growth, Schuyler said, means the Schuylkill's water is healthy.

"I'm not an environmental purist," he said. "They think things should stay the way they are. That's not the way the world really is."

In less than 15 minutes of dragging the bar across the Schuylkill, Wachlin's workers, Efrain Santiago, 25, and Adam Lutz, 14, had hauled in a monsterish pile of milfoil on the barge's deck, their hands and legs covered in dying plant life.

Since a dredging project could be years away, Wachlin is resigned to dragging and mowing, dropping the piles by the dock before he heads back out for more.

"You see what we're up against," he said, motoring the boat back toward the dock. "Hopefully, we can just keep it at bay."