Geology professor: Drainage project could have caused sinkhole

GEORGETOWN, SC (WCSC) - Police in Georgetown are patrolling for looters around a sinkhole that partially swallowed an office building Thursday night. The building fell at least 8 feet into the ground because of a sinkhole, but luckily no one was injured.

About eight businesses are located at Parrish Place on Georgetown's North Fraser Street.

The building's owner believes the city's drainage improvement project may be responsible for this sinkhole and three others.

Two state senators have called a meeting for Monday afternoon to discuss the issue.

Four sinkholes, all relatively close together, all near construction of Georgetown's $14 million drainage project, which Geology professor Scott Harris says may have been the trigger that sunk the street.

"When you have an area that you're naturally or artificially draining that water table, it's going to loosen up that sediment, limestone, and if there was a little bit support once you remove that water, you are going to get that kind of collapse," Harris said.

A 10-foot hole, collapsed walls and ground sinking beneath your feet. Harris says areas from Harleyville up to Georgetown have thick layers of limestone under the ground.

When Harris drops an acidic mixture on the rock it dissolves. Acidic water under ground does the same thing to limestone over time.

"You have materials down there that are really spongy, and you have a roof element," Harris said. "Until that roof reaches a threshold it will stay there, but once you get enough material mined from underneath, of course its going to collapse."

That is what he says happened to the UPS store on Highway 17 late Thursday night.

"The sinkhole was probably developing under there even before they saw the collapse," Harris said.

He added that if the project was the cause of the sinkholes, more damage is possible.

However, he says it can be prevented by replacing those areas under the ground with loose sediment with pilings to hold up the ground surface.

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