Water district is monitoring South Laguna slope where sinkhole swallowed a Range Rover

Residents in South Laguna still recovering from a massive flow of mud released when an 8-foot sinkhole opened up last weekend worried on Friday what additional hazards more rain might bring.

Mud and debris flowed about 300 yards through backyards starting at Sunset Avenue, down through a fence into several homes along Virginia Way and then headed down 10th Avenue across Coast Highway to Thousands Steps Beach where plumes of mud could be seen in the ocean.

Officials with the South Coast Water District, who have worked all week with crews from Ocean Blue Environmental Services and ATI Restoration, said about 110,000 gallons of water were discharged from a water main broken on Sunday, March 5, after the sinkhole started forming. When the surface gave way it swallowed a Range Rover parked along the street.

Emergency personnel from Laguna Beach responded to the scene Sunday morning after reports of water, as did water district officials.

The first call came in around 7 a.m., after a resident on Sunset observed water bubbling and pooling on the asphalt street near the location that nearly an hour later became the sinkhole, said Sheena Johnson, a spokesperson for the water district. When the sinkhole broke through, the Rover fell onto a gas line and ruptured it. The immediate area was temporarily evacuated. Johnson said the vehicle was hauled out and was able to be driven away.

Geologists hired by the water district this week studied the location and as of Friday, March 10, didn’t have an answer on what caused the water main to break. The line, Johnson said, was relatively new, installed in 2004. They were able to determine that the water main broke after the sinkhole formed, she said.

“Geologists are looking at the angle of the slope, slope stability and the saturation of the soil,” Johnson said. “Preliminary investigating shows the slope has no movement, but we have staff out there monitoring it.”

Marie Clark, one of the property owners on Virginia Way whose home was in the direct path of the mud flow, said her home had been hit with a nearly five-foot-tall wall of mud on Sunday.

“The waterline break kind of trenched a riverbed to my house,” she said, crediting the water district for its response and removing the mud from the back of her house. She had feared the whole house might have been pushed down the slop, she said, when the wall of mud busted through her fence and blasted into the back wall.

She said water district officials have been vigilant in protecting her home and have stacked sandbags at the back and up through her and a neighbor’s yard along the path from the sinkhole.

“They are coming to my house almost every hour to see what’s happening,” she said.

Johnson confirmed that crews from the district have also stacked sandbags around the sinkhole, adding, “We’re trying to protect the area as much as possible because of the rain.”

Mike Tompkins, who moved his truck that was parked behind the Range Rover when he saw the water bubbling, said he’s also been happy with the level of service from the water district and appreciates the preventive work done to safeguard the neighborhood as more rain falls.

“I heard a boom and a whoosh in the hillside before the street went,” he said. “It was no longer bubbles in the asphalt, but a geyser. It didn’t take long for the water flow to erode the street. It was like a sudden flash flood with an enormous amount of debris that charged through everything in its way. Mud plumes went far out into the ocean.”

As a general contractor who reinforced his own home’s foundation 20 years ago, he feels somewhat confident, he said, about the slope’s stability, but worries about the street in front of his home.

“We likely have a more unstable street than other areas of the community,” he said because of prior patchwork on the road. “There are many streets in South Laguna that would love some attention. A guard rail seems to have held the street and hillside together. Now, they’ll be forced to do it right.”

While city officials did not comment on the sinkhole, Mayor Bob Whalen said the city maintains all its roads on a seven-year cycle where they slurry seal and fill the cracks and potholes.

“The city always looks at situations like this after the fact,” Whalen said, “and sees what we can learn and if future actions are warranted.”