Torrential rains came on a May night in 1989 as about 200 people were folk dancing inside the Spanish Ballroom at Glen Echo Park in Montgomery County.

Rocks, mud, assorted debris, even trees were swept down an embankment from MacArthur Boulevard, clogging a culvert that normally would have carried off the water, channeling it under a large parking lot and into a ravine.

The parking lot flooded, then part of it collapsed. Sixty-three cars were swept toward the Potomac River 400 yards away; nine wound up in the river.

It took about a month to recover all of the folk dancers' vehicles. A 70-foot-long gorge carved by the flood still splits the parking lot at the former amusement park administered by the National Park Service, which offers a variety of educational and cultural programs in addition to folk dancing.

Fenced off to vehicular and foot traffic, the gaping hole has been partially filled with dirt, and cars are allowed on the back end of the lot.

"What you see out there right now is pretty much the condition it's been in for about a year," National Park Service spokesman Earle Kittleman said recently.

Park officials have completed the design for a new lot that would eliminate the culvert and establish a creek bed through the parking lot. The lot will not be as steep as it is now and will have fewer parking spaces -- 210 instead of 300. Park visitors will cross the stream on a 12-foot-wide foot bridge.

New lighting and trees are planned to "restore the natural terrain look," Kittleman said.

When construction begins in August, no parking will be allowed on the lot but visitors will be able to use MacArthur Boulevard and parts of Tulane Avenue.

In the meantime, Kittleman said, the lot is stable and cars are in no danger.