There's a deep yellow tinge on the willow branches along the C&O Canal near Fletcher's Boathouse.

The sap is rising. Spring is near.

"Oh yeah," said Dicky Tehaan, the best all-around fisherman on the D.C. stretch of the Potomac River. "As soon as the level drops I'll be down here looking for calm water, fishing for crappies in the back eddies."

It will be awhile. Today the river is raging, rampaging. It's no place for sport.

Sometime early Sunday it picked up the Fletchers' 50-foot floating boat dock, ripped it from its moorings, carried it 100 feet up the bank and deposited it in the driveway, surrounded by hundreds of tons of ice.

The boat dock was built by Julius Fletcher and his sons, Joe and Ray, after Hurricane Agnes tore away its predecessor and all the Fletchers' boats in 1972.

This time "an ice jam must have done it," Joe Fletcher said yesterday as he surveyed the scene. Half the parking lot was under water. Wavelets were lapping 10 feet from the concrete snack bar. A pair of mallard ducks paddled in and out of the trees.

He theorized that ice floes backed up at Key Bridge, creating a temporary dam. The cascading river water rose behind it, perhaps five feet or more.

Finally the dock broke free from its steel mooring cable and floated onto the bank. Then when the ice dam burst, "it was like taking the stopper out," Fletcher said. The dock was left high and dry.

Yesterday, with flood waters still rising,there was nothing to do but watch. The crest wasn't due until early today.

The brown water thundered by, bearing huge stumps, oil drums, whole trees. Fletcher and Tehaan listened to the roar.

"As long as you can hear it the water's still coming up. When it starts to fall you won't hear that roar anymore" Tehaan said.

The Fletchers will wait until the flood recedes. Then, as they have done so many times before, they will rebuild the battered dock.

This time it will be Ray and Joe's job. Julius Fletcher, who watched the river rise and fall for most of his 67 years, succumbed to cancer on Saturday after a painful, year-long battle.

The young Fletchers won't work alone. "I've got 40 phone numbers of people who have already offered to help," Joe said.

The good news to the multitudes for whom spring means crappie and perch fishing off Fletcher's is that the experts see little chance that today's floods will significantly affect tomorrow's fishing.

The new dock will be built by midMarch. The rental rowboats were out of the rising water's range.

The high, muddy water will stall the instinctive upstream march of spawning fish, but only briefly.

When will the white perch arrive?

"March 20," said Joe, "give or take a half-dozen days."

That's a guess, of course. But Joe Fletcher has seen a lot of spring perch runs.

The good crappie fishing should precede that by about a week.

Both species will be caught on minnows; worms will work well for white perch after they've arrived en masse. Sportsmen like Tehaan will go after crappies in still water, casting small jigs and tiny darts.

"Three or four days after we catch the first perch, they'll be in here in swarms," Joe said.

The perch will travel up the big river from holes downstream, searching for a place to deposit their eggs. The crappies will head for the shallow eddies for the same reason.

Once they've performed this annual dance of life, they will be followed in turn by herring, shad and striped bass.

Native river fish like black bass and bluegills will head to the shallow water to do their mating.

Floods will subside, the willows will sprout their pale leaves, and before long it will be summer. Another season will have come and gone, leaving no mark at all on the ageless Potomac.