Most of the dams in Richland County that broke in this month’s torrential rains were cited repeatedly in state inspection reports for deficiencies, according to records released Monday evening by state officials.
Among the problems are cracks and holes in the dams, as well as overgrowth that made it impossible, in some cases, for inspectors to thoroughly review the dams.
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In one case, erosion was discovered in the same area of a dam during six inspections over two years, according to S.C. Department of Health and Environmental Control records.
All told, 17 community dams have failed in Richland County since Oct. 4, including 15 regulated by DHEC.
Of those, 11 dams showed repeated deficiencies over several years that the agency sought to correct. DHEC had no record for three of the dams. Two others are not under the agency’s jurisdiction, including the Pine Tree dam that blew out early Oct. 4 and sent water cascading to Cary Lake, where another dam broke. Cary Lake received good inspection reports from DHEC.
Records reviewed Monday night by The State newspaper show dams at Walden Place Pond, Upper Rockyford Lake, Lower Rockyford Lake, Murray Pond and Lake Elizabeth are among those where repeated deficiencies were reported in several inspections during recent years.
Dam failures are among the legacies of the Oct. 4 deluge, which dumped as much as 17 inches of rain on parts of the Columbia area. The records do not indicate if the dams failed because of the deficiencies. Some local officials have said last week’s historic rainfall was the primary cause.
While heavy rains flooded many parts of town, dam failures are believed to have made the situation worse. Water levels rose quickly in some low-lying areas, indicating that a burst of water from a dam contributed to the flooding, some residents said. Dam failures were a problem statewide during and after last week’s storm, but the bulk of them occurred in Richland County, many in the Gills Creek watershed that runs through Columbia.
DHEC inspectors visited Walden Place Pond dam off Spears Creek Church Road six times between April 2013 and April 2015 because of ongoing erosion, seepage and tree problems, according to the records. Inspector Steven Hauptmann rated the 65-year-old dam near the affluent Woodcreek Farm neighborhood in poor condition on all six inspections, the second-lowest mark on DHEC's scale.
In an April 3 letter to Allen Shumaker of Walden Place Limited Partnership, Hauptmann gave the dam owner 30 days to lower the pond level and provide an action plan for repairs after an evaluation by an engineer. Problems included heavy erosion on the upstream side of the dam and seepage at the bottom of the dam as well as trees on the side of the dam and vegetation growing on the emergency spillway.
“Erosion should be corrected ASAP,” Hauptmann wrote on the April inspection.
Four months later, Hauptmann emailed DHEC Midlands Area Director Harry Mathis to say that the pond level was lowered, but Hauptmann said he had not received the plan for repairs. Hauptmann said he sent a certified letter Aug. 24 to the dam owner.
That was the last communication in the file released by DHEC.
Efforts to reach Shumaker were unsuccessful Monday.
The Upper Rockyford Lake dam, which blew out a day after the Oct. 4 torrent, has been cited at least three times in recent years for having trees and vegetation on the earthen structure. Trees on dams are a concern because they can create cracks that can destabilize the structures.
DHEC’s most recent inspection report, written in August, cited evidence of erosion on a slope of the dam, which is in the Arcadia Lakes area between Trenholm and Percival roads. A 2012 inspection document says DHEC asked on eight different occasions, beginning in April 1997, for small trees and vegetation to be cut. But the report said those items had not been corrected.
Tom Teuber, a leader in the Upper Rockyford Lake homeowners group, said his association has tried its best to follow DHEC’s requests to improve the dam by regularly clearing some of the vegetation, although the large trees still exist. “We have been fairly aggressive’’ in maintaining the dam, Teuber said. “We want the dam to be in good shape.’’
He noted that the part of the dam that failed last week was a concrete spillway area, not the actual earthen part of the dam where trees have been growing.
The Murray Pond dam in Lower Richland was last inspected in 2009, according to the documents provided by DHEC. After that inspection, agency engineer Steven Bradley wrote that the dam “appeared to be in good condition” after unspecified repairs in 2007.
He suggested the Lake Dogwood Homeowners Association start a fund to rehabilitate the concrete on the emergency spillway because it “could be costly.” The repairs were not needed immediately, Bradley wrote, and operating the dam to prevent overflow could help the need for the repair.
He also reminded the homeowners association that if water overtopped the 85-year-old dam or if the structure failed, the association should block U.S. 601 north of Garners Ferry Road and notify property owners downstream.
Another dam that failed, at Lake Elizabeth in northeast Richland, showed evidence of decaying concrete in both 2012 and 2014 inspections.
Inspection reports from both years noted a small crack near the Lake Elizabeth sign and evidence of holes in the dam.
The most recent report raised the possibility that small animals were digging holes in the dam, which can destabilize it. A tangle of trees, brush and briars “made it impossible to conduct a thorough inspection’’ of soil conditions for signs of cracks, seepage or sinkholes in the dam, according to the report by DHEC inspector Hauptmann.