North Carolina state officials on Friday cited Duke Energy for a 40-foot-long crack in an earthen dam at the 2012-retired Cape Fear Plant’s ash impoundment, to which the company last week made emergency repairs.
The North Carolina Department of Environment and Natural Resources (DENR) issued Duke Energy with a notice of deficiency on Friday for the longitudinal crack that had a maximum width of about four inches. Duke Energy personnel first observed the crack in early March when “it was very small and appeared to be associated with a small, shallow slough that would not be a serious threat to the stability of the dam,” a DENR inspection report says. The company notified the DENR that the crack had enlarged on March 20 and that Duke Energy was developing an emergency response plan to address the problem.
Duke Energy repaired the crack on March 25 by removing portions of the earthen dam where the crack formed, flattening it, and then stabilizing it with a layer of geotextile fabric and riprap.
DENR noted that no water had leaked through the crack before repairs at the 1923-commissioned coal-fired power plant’s 1985-constructed ash impoundment. It also admitted the company’s emergency repairs to the dam after the state approved an emergency response plan in mid-March were “sufficient to prevent a possible dam failure.”
However, DENR called on Duke Energy to continue maintenance work to ensure the dam’s stability. The notice also requires the company to complete comprehensive engineering reports and plans by April 7 for state approval, as well as to submit an emergency action plan, which establishes procedures for public notification if the dam were to fail.
DENR said the dam is considered a “high hazard dam because of the potential environmental damage if it were to fail.” The state regulatory body also said Cape Fear’s impoundment is “one [of] two from which the utility had been pumping out millions of gallons of water without regulatory approval.”
Following the Feb. 2 coal ash spill at Duke Energy’s Dan River Steam Station in Eden, N.C.—which was also retired in 2012—DENR conducted inspections at all 33 coal ash impoundments in North Carolina. “On March 11, during the agency’s inspection of the impoundments at the Cape Fear plant, DENR discovered the pumping activity when staff engineers observed substantially lowered water levels in the ponds, as well as nearby pumps and hoses. DENR issued Duke Energy with a notice of violation for the pumping activity on March 20,” the agency said.
Duke Energy could face a fine if it misses the April 7 deadline, or if the dam fails and results in loss of life. As POWERnews reported, Duke Energy is planning to convert three of its remaining North Carolina coal-fired units to dry fly ash systems or retire the units. The Eden site is one of 12 owned by Duke Energy for which the state sued the company last year for failing to properly store coal ash and coal residuals.
Duke Energy on March 26 said in a statement that it is moving “aggressively” to take a number of actions to to evaluate long-term solutions for ash basins. It has to date established an internal strategic task force headed by CEO Lynn Good. It has also commissioned third-party assessments of all its ash basins, which are due by May 31, 2014.
After securing the required permits, Duke Energy will finally move ash from three retired plants, accelerate closure of an additional basin, convert to dry ash handling at all remaining facilities in North Carolina, and begin dewatering the other retired basins.
—Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)