COLUMBIA, SC As the Waccamaw River swells this weekend, concerns are rising about potential contamination from a coal ash pond, septic tanks and hog farms that contain potentially harmful bacteria and metals.
The Santee Cooper power company was working this week to protect a coal ash pond that is under pressure from the Waccamaw. The ash pond, west of Myrtle Beach, contains at least 660,000 tons of the toxin-riddled ash at Santee Cooper’s old Grainger power station.
Water is within three feet of the top of a retaining wall around the Grainger site near Conway, said Waccamaw Riverkeeper Emma Gerald Boyer.
Soaking rains from Hurricane Matthew last weekend caused the Waccamaw to rise in North Carolina and that water is now working its way down river into South Carolina, where Conway and small communities nearby are flooding.
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“You never know with this much water; it could affect the integrity of the containment,’’ Boyer said. “Dams will just collapse due to pressure, as opposed to only washing over the top.’’
Santee Cooper spokeswoman Mollie Gore said the utility has no reason to believe the Waccamaw will rise so high that the river will pour over the ash pond. The company said containing walls around the pond are sound and will hold up.
Gore said the waste lagoon remained in good shape during last year’s historic flood, as well as in Hurricane Floyd in 1999 – the latter of which carried higher river levels than what are expected this weekend.
But Gore said the company has noticed some seepage in the waste lagoon and is now pumping water back into it to relieve pressure from the rising Waccamaw. Pond levels had been lowered long before Matthew as part of a plan to dig up and remove all of the coal ash. About half of it remains. The seepage is in an area where ash has largely been cleaned out, she said.
“We are proactively working to mitigate this pressure from the flooding river,’’ Gore said.
A statement from the S.C. Department of Health and Environmental Control said the agency had been told by the power company there are no problems.
Coal ash ponds can be major sources of water pollution, if not properly protected, because they contain arsenic, mercury and other poisonous materials that can build up in fish or pollute drinking water.
The Waccamaw River is expected to crest near Conway at 17 feet as soon as Saturday and remain at that level through at least Wednesday, according to the National Weather Service’s river level prediction service. The river level would be six feet above what’s considered flood stage. The record river level at Conway is 17.8 feet, set in 1928. Last year’s flood sent the river level to 16.2 feet, according to the weather service. Hurricane Floyd in 1999 caused the Waccamaw to rise to 17.6 feet.
Meanwhile, DHEC spokeswoman Jennifer Read said Friday the department is concerned about septic tanks washing out and polluting the river, which runs through South Carolina from near S.C. 9 to Conway. The river then meanders to Georgetown on the Atlantic Ocean. There are also concerns about public sewers overflowing.
“Flooding can limit the effectiveness of septic systems,’’ Read said in an email. “DHEC urges everyone not to use area streams, rivers or the ocean for drinking, bathing or swimming due to the possibility of bacteria, wastewater or other contaminants. Avoid wading through standing water due to the possibility of sharp objects, power lines or other hazardous debris that might be under the surface.’’
Septic tank leaks could be the most likely source of contamination to the river, if last year’s historic 2015 flood is any indication.
Boyer said her organization documented elevated bacteria levels a month after the October 2015 flood. Some of that might have been from septic tank pollution that took time to work its way through the saturated soil and into the Waccamaw, she said. E-coli bacteria can indicate the presence of pathogens that could make people sick if they come in contact with the water.
Christine Ellis, who works with Boyer at the riverkeeper group, said some of the elevated bacteria levels in November 2015 also could have come from hog farms in North Carolina. During a flight over eastern North Carolina this week, Ellis said she didn’t notice any hog waste lagoons in the Waccamaw basin that had been inundated by the river.
But Ellis said systems that spray hog waste on farm fields are a concern. If water is over sprayed to relieve pressure on hog lagoons, it could run off and into the Waccamaw upstream from South Carolina, she said.
Read said DHEC found that two lagoons – one of them in Horry County – had overtopped Thursday, but “visual assessments” Friday by agency inspectors indicate that both lagoons are stable.
It was unclear from DHEC’s response whether the Horry County hog lagoon was located in the Waccamaw River watershed.
Read said the owners of the waste lagoons – the other is in Williamsburg County – are working with DHEC to lower water levels in the waste lagoons. DHEC found the overtopped lagoons while checking hog farms in areas of eastern South Carolina that received heavy rain from the hurricane.