Golf Course’s New Hole a Hazard : Emergency: A sinkhole 80 feet long, 40 feet wide and 30 feet deep threatens to undermine Pacific Coast Highway and utility lines in Dana Point. A crumbled drainage channel is believed to be the cause.

Emergency crews are scrambling to repair a huge crater in a Dana Point golf course and a damaged underground drainage channel that threaten to undermine the nearby Pacific Coast Highway and sewer and gas lines.

The hole, estimated to be 80 feet long, 40 feet wide and 30 feet deep, was discovered by maintenance workers near the 13th green at The Links at Monarch Beach golf course Feb. 21.

At first, nobody knew what created the mysterious hole, but eventually, Orange County public works officials found evidence that an aged drainage channel 30 to 40 feet underground had partly crumbled, probably causing the ground above it to sink.

“It could cause catastrophic failure if the roof (of the channel) was to finally cave in,” said Jim Miller, Orange County’s chief of flood control design. “The main thing is we don’t want additional movement or dropping to occur.”

The potential for problems--the four-lane coastal highway is only 25 feet away--prompted the County Board of Supervisors this week to declare a local emergency in the area and authorize an initial $200,000 for repairs.

By Thursday, county crews had begun fixing the broken 14-foot-high drainage channel, although officials still do not know the extent of the damage. Workers are laboring in the damp darkness of intact sections of the channel, trying to support the vulnerable tunnel with a concrete foundation.

“It’s really like a mining operation, working deep inside the culvert,” said Jim Williams, an engineer for the county’s Environmental Management Agency.

The project could take six months and hundreds of thousands of dollars to finish. And, if the hole expands, it could cause a break in the highway, Williams said.

“If the situation continues to deteriorate, it could cause damage to PCH,” he said. “If it was sudden, someone (on the roadway) could get hurt. But we are in there to prevent something like that from happening.”

Golf course spokesman Ben Cagle said the course remains open and there is no danger to players. The damaged area has been roped off and lies just off the 13th green near the Ritz Cove housing development on the ocean side of Pacific Coast Highway.

The crater in the golf course apparently appeared overnight, Miller said. Golf course employees “told us when they went home on Sunday afternoon, everything looked OK, but when they came in on the 21st, they saw it,” Miller said.

County crews later discovered that the sinkhole was only a symptom of a problem about 30 to 40 feet underground, Miller said. The sinkhole can easily be filled, but fixing the underground channel will take much longer, Miller said.

Most of the damage is near a junction connecting an old section of the storm drain to a newer one, Miller said. A break at the junction has allowed water to seep into the ground and dirt to sink into the big channel.