Aiken County officials knew that the dam at Langley Pond near Warrenville had a significant problem, but they didn’t realize just how big it was until the structure’s old ogee crest spillway was being removed.
During the work session prior to County Council’s meeting Jan. 7, County Deputy Administrator Brian Sanders showed the panel photographs of a large void in what should have been a solid barrier.
“It was a bit of a surprise,” County Administrator Clay Killian said.
The empty space “was/is massive, at least 20 feet long and up to six feet deep in some places,” County Engineering Director Teresa Crain wrote in an email to Killian and Sanders last month.
A major project to renovate, repair and strengthen the dam is nearing completion, so the void no longer poses a threat to the structure's stability.
The groundbreaking ceremony was held in March 2018.
Almost all of the work is scheduled to be finished “around the end of February, which means for all practical purposes, the new (labyrinth) spillway will be functional,” Sanders told the Aiken Standard last December. “As with any construction project, there will be a punch list items that will need to be completed after that time,” he continued. “We anticipate two to six weeks to complete the punch list items.”
That still is the case, Sanders indicated, during the Jan. 7 work session.
“We definitely made the right decision in replacing the dam,” Crain wrote. “It was only a matter of time before the old spillway would’ve had a catastrophic failure.”
Crowder Construction Co. is the contractor for the project. Schnabel Engineering created the design and is overseeing Crowder’s efforts.
The amount spent to date is $13,149,614, Crain wrote in an email to Killian and Sanders last week.
A $6 million Hazard Mitigation Grant from the Federal Emergency Management Agency, a $9 million general obligation bond and Capital Project Sales Tax proceeds are providing money for the project, Killian said.
County Council Chairman Gary Bunker, who also was surprised by the size of the hole in the dam, told the Aiken Standard last week that, based on a recent report, the project is expected to “come in under budget.”
In late 2014, a man who was walking his dog noticed the water’s color in the creek below the dam looked different from normal.
“There was a little bubbling,” Killian said. “It was like if you were boiling a pot of water. The water just kept bubbling, and, obviously, there was air coming up from somewhere.
“We went out and looked at it,” he continued, “and it got our attention pretty fast. We pulled the water (in the pond) down, and we started trying to figure out where the problem was. We had engineers and other consultants come out and start doing testing and things like that. They determined that we had a problem that needed to be fixed on a permanent basis.”
In particular, a dye test showed there was something seriously wrong with the dam.
“The dye passed through (the dam) much quicker than they thought it would, so that gave us some concern that there was something underneath the spillway that was causing this problem.” Killian said. “The leak obviously was fortuitous because it made us start doing some checking and testing that we would not have done otherwise. The dam is inspected regularly, on an annual or biannual basis I think. We pull down the water and the inspectors from DHEC (South Carolina Department of Health and Environmental Control) come and look. But this was something I don’t think would have shown up without that leak bubbling up.
“There had been a problem, obviously, for a while,” he concluded.
Langley Pond’s dam originally was built in the 1850s and primarily was an earthen structure.
Former County Engineering Director Joe Berry, who retired in 2018, told the Aiken Standard that the old ogee crest spillway had been part of the dam since the 1950s.
Had there been a catastrophic failure in the dam as a result of the void, “I don’t think there would have been a loss of life, but it could have escalated to that,” said Crain after the groundbreaking ceremony Jan. 10 for the first phase of the Aiken County Public Library renovation project. “We have an inundation map that shows the area downstream that would have been flooded. There are about 10 homes that are in the flood plain that would have been flooded.”
Killian, who also was at the ceremony, said he didn’t believe the homes would have been “washed away.”