As the dregs of Hurricane Ivan spun north, waterman Bill Gunther checked the water level in Harrisburg, Pa., to see what was headed down the Susquehanna River toward the Chesapeake Bay. "If I know a flood's coming, I'll try to prepare, get my gear out of the water," he said from his home in Bush River, near Aberdeen, Md.

But it was too stormy for him to get out much last weekend, and by Monday, a surge of water teeming with junk had rushed into the upper bay. The debris alarmed the U.S. Coast Guard, which warned boaters to watch for obstacles, and environmentalists, who worry about the long-term effects on grasses and bay critters from sediment and pollution.

"This throws a huge slug of nitrogen into the bay," said John Page Williams, senior naturalist for the Chesapeake Bay Foundation. "And nitrogen's a killer."

He could see the change from the air as he flew in from Maine -- there was a big plume of brown water coming down the river toward the bay -- and from a skiff Thursday morning as he measured changes in the water.

For many watermen in the upper bay, it was a lousy end to the crabbing season. Gunther went out last weekend to try to save his crab pots but had to turn back because of high winds.

By midweek, when sunny skies returned, he still could hardly get his 35-foot fiberglass boat through the trash in the bay. He saw trees in the water with the roots still attached, as well as logs, chunks of wood, grass, brush, 60-pound propane tanks, trash cans, tires, kiddie pools, plastic scooters, lawn chairs.

"You name it, it's out there," he said. "You could probably hop from log to log all the way across the bay if you were nimble enough. . . .

"And the water is so absolutely filthy stinking dirty, I don't know how anything could survive out there."

As all the wood became waterlogged and heavier, it sank, making it even harder to navigate safely.

So he drove around -- puttering about 6 knots instead of his usual 18 or 20 -- looking for the black-and-white floats that mark his more than 300 crab pots. "It was a real mess," he said. Some were tangled up in big logs. Some were dragged out miles away when the floats got caught on debris.

"Every other commercial crabber in the [upper] bay

was doing exactly the same thing I was doing -- working as hard as you can, as quick as you can," Gunther said.

He lost 60 or 70 pots, each worth about $25, and will have to spend $400 or so to replace the dinged-up propellers on his boat.

Worst of all, it brought a crab season that had just started to become profitable for him to a sudden, messy end. On Wednesday, he brought in 200 pots with a catch of just two bushels of live crabs, about a quarter of his typical yield. Over and over, he threw dead crabs overboard.

"They can't take the fresh, muddy water," he said, especially when trapped in pots. All that gunk is moving down the bay, along with the silt that can smother underwater grasses and oyster beds.

Gunther has more scavenging to do, watching for his floats, pulling in pots, dumping out the dead crabs.

But the season is over, he said.

"I'm done. I'm finished. In this part of the bay, there won't be a live crab left anywhere. They're running as fast and hard as they can to get away from this filthy water."