With torrential rain forecast for SC, are dams safer than in 2015? Here’s what we know
Nearly a decade after dams broke across South Carolina from an historic rainstorm, government officials are hoping their efforts since then have been enough to prevent a repeat of the 2015 disaster that caused flooding like few people had ever seen in the state.
Since the October 2015 flood, scores of aging, earthen dams have been rebuilt or improved in an effort to prevent failures like those nine years ago.
At the time, about 70 dams regulated by the state — including a string of them that form residential lakes in Columbia’s Gills Creek watershed — fell apart or breached in the intense rainfall.
Among those were dams at Spring Lake, Cary Lake and Lower Rockyford Lake, all in the eastern Columbia-Forest Acres area. A federal dam on Fort Jackson, the one at Semmes Lake, also broke, sending a torrent of water into the Kings Grant neighborhood and lower Devine Street.
Collectively, the cascading effect of the failed dams flooded major roads that almost never flood. One unsuspecting Columbia resident drowned on lower Devine Street when he drove his car into the water, sparking a wrongful death lawsuit against the federal government. The suit was not successful, even though federal records show that inspectors had found deficiencies in the dam years before.
Lower Devine Street impassable for days, resembling a small lake. All told, nine people died in the Columbia area during the flood.
Many dams in the Gills Creek watershed were rebuilt or repaired after 2015 and the state has beefed up its dam safety program., although national reports show the state still needs to make more progress in overseeing dams. Questions also have surfaced about federal oversight.
One of the dams that failed in 2015 was at Fort Jackson’s Semmes Lake, which has since been renamed by the federal government as Inchon Lake. That dam is now designed to withstand substantially more rainfall than the dam that blew out in 2015, a fort spokesman said.
“The community should have high confidence in the rebuilt dam,’’ spokesman Thomas Byrd said in an email Monday.
Still, state officials said they were on the lookout for problems across South Carolina.
Myra Reece, who heads the state’s environmental agency, said during a news conference Monday that the department had looked at 19 dams that it had questions about. She did not identify the dams during the session with reporters or say what part of South Carolina they are located in.
“Our team conducted pre-storm assessments of dams we felt might be vulnerable to this type of intense storm, and we are working with the owners.”
Bailey Parker, director of the Gills Creek Watershed Association, said she’s encouraged that multiple dams are in better shape today than nine years ago and dam owners are working together to manage them. But Parker and those who live in the watershed are on watch for signs of trouble, she said.
“People are nervous,’’ Parker said. “I don’t want people to be nervous, but I appreciate that they remember what happened and realize it could happen again..’’
Parker said the looming rainfall has people “on edge. It could be nothing or it could be a repeat of 2015.’’
Flood waters from a historic October 2015 flood cover the dam at Spring Lake in Richland County. A truck was washed into Forest Lake from a road that ran across the top of the Spring Lake dam
As of Monday afternoon, the forecast for Columbia did not show rainfall amounts like those that fell in 2015. About 20 inches of rain fell over a weekend that year. The forecast for the Columbia area, for now, is showing rainfall of up to 6 inches by Thursday.
But most of that rain is expected Tuesday and Tuesday night, and National Weather Service forecasters concede the track of Hurricane Debby in the Midlands contains uncertainty.
“The heaviest rain looks to be off to the east (of Columbia), but it really is going to come down to where exactly Debby is going to go for the rest of the week,’’ said Chris Rohrbach, a meteroologist with the weather service.
Statewide, South Carolina has about 2,300 state regulated dams, more than a third of which pose high or significant hazards to people and property if they break. Many of the dams are earthen structures and some were built decades ago.
All told, 169 high hazard dams in 2020 were rated poor or unsatisfactory, according to a report that year for the environmental agency. But overall, the 2020 report said 60% of the dams that breached in October 2015 were repaired, removed or exempted from regulation. At the time, about 20 percent were being repaired or scheduled for repairs.
State regulated dams are typically smaller dams that hold back the waters of moderate sized lakes, such as Forest Lake in Columbia. Large dams at reservoirs like Lake Murray are regulated by the federal government.
Because of concerns about dams, the S.C. Department of Environmental Services urged dam and lake owners to clear spillways that might be clogged, lower water levels and monitor the dams during the next several days.
The operators of Cary Lake, Spring Lake, Forest Lake, and Lake Katherine began releasing water Sunday to lower water levels in advance of the storm, Parker said in an Instagram post.
The stability of dams is not an issue only in central South Carolina. Other parts of the state, particularly the eastern and northwestern parts of South Carolina, have clusters of dams — and some of them failed during the 2015 storm. Fewer dams are found in the Lowcountry near Charleston and Beaufort, state records show.
Meanwhile Monday, state officials said the water levels had been lowered in some of the state’s major lakes, including the lakes Marion and Moulrie between Columbia and Charleston, as well as Lake Murray near Columbia.
The Pine Tree Lake dam was one of several dams in the Gills Creek watershed that breached. Here, SC DHEC employees inspect the dam.
Staff Writer Ted Clifford contributed to this story.
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