State examined 19 potentially shaky dams as storm approached SC. Here’s where they are

The state Department of Environmental Services has released the names of 19 potentially shaky dams it raised questions about, including about a half dozen in the Columbia area, as Tropical Storm Debby moved through South Carolina.

Officials said their initial worries have been mollified and they have not found “heightened safety concerns’’ at the dams. But the department will continue to monitor the dams. The structures were checked because they were in areas expected to receive at least six inches of rain and had known issues before Debby’s arrival.

Dams of concern identified by the DES include structures at Richland County’s Adams Pond, which was checked because of spillway damage; Lexington County’s Batesburg Reservoir, checked for insufficient spillway capacity; Lexington County’s Whisper Lake, checked for voids; and Calhoun County’s Derrenbacher and Paradise ponds, checked for slope stability and insufficient spillway capacity.

The agency also looked at two Kershaw County dams: the Upper Sunnyhill Dam, where inspections were done for spillway damage, and the Hermitage Mill Pond dam, checked for excessive seepage.

Dams of concern also were examined in parts of eastern South Carolina’s Pee Dee region, as well as in Orangeburg, Aiken and nearby counties south and west of Columbia.

“Once rainfall and floodwater from Tropical Storm Debby have subsided, SCDES will deploy trained teams across the impacted area to perform post-storm assessments of these flagged dams, as well as high and significant hazard dams located in areas with substantial rainfall accumulation,’’ the agency said in a statement Wednesday before Gov. Henry McMaster’s press conference on the tropical storm.

Myra Reece, the DES director, said during the press conference that, all told, her agency will be looking at several hundred dams as early as Friday for signs of damage. The assessments will be done when the storm has begun to diminish.

“That’s going to be really critical information for us to tell us how they fared, and if it put some of the dams in condition that we need to require some action’’ from dam owners, she said.

So far, Reece said she was only aware of one dam that breached as the storm moved over the state. But that was not among the 19 her agency checked. That dam was an unregulated structure in Colleton County, she said..

While there are signs that the worst of Debby may have moved through South Carolina, Reece said “We’re not out of harm’s way. So it’s so important for our dam owners to continue to stay vigilant and observe current conditions at their dams.’’

The safety of dams has been a point of concern across South Carolina for years, particularly since a 2015 flood blew out or damaged at least 70 state-regulated structures, as well as others that were not regulated.

At one point, the state had one of the weakest dam safety programs in the country and critics blamed the 2015 failures on poor state oversight. But the dam safety program has been bolstered with more staff and money since 2015. Reece boasted of the program’s efforts earlier this week.

Since the 2015 flood, scores of dams have been rebuilt or upgraded, particularly in areas where they pose a risk from a breach. That includes Columbia’s Gills Creek Watershed, where dams form a string of residential lakes. In 2015 dams along Gills Creek burst, flooding major intersections and resulting in multiple deaths.

Despite progress in improving the state dam safety program, it has been criticized as not being adequately funded.

A recent report by the American Society of Civil Engineers said that while the state had increased spending from about $200,000 annually to more than $1 million annually by 2018, more work is needed. The report said spending on high hazard dams falls well below the national average of $4,875 per dam. The report gave the state’s dam oversight effort a grade of “D.’’

The state Legislature, while providing money for the program, has been reluctant to tighten some laws after complaints from rural dam owners worried about the cost of fixing suspect dams. Most of the dams in South Carolina are privately owned.

Overall, the state has about 2,400 regulated dams and an estimated 20,000 to 40,000 more that are not regulated. Dams in urban areas are of particular concern because a breach can send dangerous amounts of water into communities below them. Dams regulated by the state hold back the waters of small and mid-sized lakes. The federal government regulates major reservoirs such as Lake Murray.

Here is a complete list of the 19 dams state inspectors looked at:

This story was originally published August 7, 2024 at 3:08 PM with the headline "State examined 19 potentially shaky dams as storm approached SC. Here’s where they are."

Sammy Fretwell

The State

803-771-8537

Sammy Fretwell has covered the environment beat for The State since 1995. He writes about an array of issues, including wildlife, climate change, energy, state environmental policy, nuclear waste and coastal development. He has won numerous awards, including Journalist of the Year by the S.C. Press Association in 2017. Fretwell is a University of South Carolina graduate who grew up in Anderson County. Reach him at 803 771 8537. Support my work with a digital subscription