Much of the Chesapeake & Ohio Canal National Historical Park from northwestern Montgomery County to Cumberland, Md., will remain closed for recreation for the rest of this year while volunteers begin to clear some of the tons of debris deposited by massive flooding in November, National Park Service officials said.

The 24 miles of towpath from Georgetown to Seneca -- which attracts hikers, fishermen, birdwatchers and others at the rate of about 6 million visits a year -- is eroded and damaged in some places and is not good for biking or jogging, but will remain open, Park Superintendent Richard Stanton said.

But piles of trees, trailer parts, household goods and other debris from the flooding clog parts of the towpath above Seneca for nearly the length of the 184 1/2-mile park, Stanton said.

Because of the constraints placed on federal agencies by the recent deficit-reduction legislation, he said, it could be four years before the cleanup is completed.

Much of the park north of Seneca was inundated and will be posted off limits this summer while efforts are under way to clean up some of the $9 million in devastation. Currently, about two-thirds of the towpath is considered hazardous and is closed.

Stanton said a 30-foot "blowout" of the canal wall south of Fletcher's Boathouse near Georgetown is being repaired, and tour barges will be operating as usual there and at Great Falls this summer.

The canal has taken a number of serious blows since it was completed in 1850 -- including the flood of 1924, which ended its commercial usefulness, and damaging surges in 1936, 1942 and other years that resulted from powerful hurricanes.

But last year's flooding -- which killed 43 people in four states and caused $900 million in damage -- came at a time when park service funding was being cut by about 30 percent.

It took $14 million and two years to clean up after Hurricane Agnes in 1972, for instance, but park officials said that for the rest of this fiscal year they are counting on only an emergency appropriation of $2 million.

In the meantime, the park service is attempting to use bulldozers where it can to clear debris, which is piled up to 20 feet high and hundreds of yards long in some spots. As much as a foot of silt covers the ground in many areas.

Much of the 160-mile stretch of towpath above Seneca, which normally attracts about 3 million people a year, is being posted off-limits and people are being "discouraged" from entering, Stanton said. Boat ramps along the length of the canal can still be used, but parking is limited.

To get a start on the cleanup, park officials are making arrangements to accommodate thousands of volunteers from such organizations as the Boy Scouts and Girl Scouts next summer as part of the Interior Department's "Take Pride in America" parks program.

The C&O park will host a jamboree for scouts from the mid-Atlantic region in June and July, and park personnel will supervise the young people as they help clear the area. Overnight camping along the park will be restricted to eight work camps for volunteers, Stanton said. All campgrounds are currently without water and have been closed since November.

That month, the rain-swollen Potomac overflowed the historic towpath and canal and inundated the nearby parkland, clogging culverts, swamping old lock houses with mud and sweeping away 20 foot bridges. Along much of the canal, the clay and gravel covering of the towpath was washed away, leaving it deeply rutted and dangerous for biking or jogging.

"When it's dry, one can walk it comfortably in several areas" near Washington, said Bruce Wood, past president of the C&O Canal Association, a group that patrols the towpath to check its condition. "If it's wet, I wouldn't try it." He said the association also is working to help clean up the debris.

Where the flood waters of the Shenandoah River joined those of the Potomac below Harpers Ferry, W.Va., "the whole towpath was blasted away," said Carrie Johnson, chairman of the Interior Department's advisory C&O Canal Commission. "Lock 32 can't be found. It was like a bomb hit."

She said 10- to 15-foot boulders were moved downstream and the Potomac River wall was pushed back more than a dozen feet.

Once used to haul coal and other goods from Cumberland to Washington, the canal fell into disuse with the coming of the railroad, and once faced the threat of being paved over as a highway. It was saved through the intervention of Supreme Court Justice William O. Douglas and others, and was declared a national historic park in 1971.

Since then, thanks to regular and long-term maintenance, it has become "increasingly durable," Johnson said. One result of that care, she said, was that while all of the aqueducts were under water in the recent flooding, none was destroyed. "If this had happened five years ago," she said, "we might have lost four or five."