Duke Energy Progress will be closing its coal-fired power operation serving New Hanover County this December. Pollutants are slowly leaching from the coal-ash basins surrounding the Sutton plant toward groundwater wells that supply drinking water for the nearby Flemington community. However, decommissioning the plant’s ash basins will not guarantee safety for nearby groundwater supplies—not for a long time, that is.
It could be years before contaminated groundwater stops flowing forth from the Lake Sutton power plant. Rick Shiver, a recently retired groundwater specialist with the North Carolina Division of Water Quality, explains that typically, in order to decommission ash ponds, all materials must be removed, and the ponds then covered with fibrous synthetic membranes or clay. However, he says that even after that’s done, it’s difficult to determine when pollution will actually decline.
"They’ll cease putting the source in there, and if they decide they’re going to go and they’re gonna put an impervious cover over the ponds, it will mitigate the groundwater impact. But it won’t go away for some time. They’ll basically put in a system of monitor wells, and they’ll basically have the opportunity to track the decline of the pollutants over time."
Duke, though, will not be performing an immediate excavation of Lake Sutton’s ash ponds once they’re retired. In fact, spokeswoman Erin Culbert says the company has yet to settle on a closure method for Lake Sutton’s ash basins.
"There will still be some period of time during the decommissioning work, which is when we will begin to dismantle some of the materials and equipment in the coal plant, where we will still need to utilize the ash ponds. But once those ash ponds are no longer needed, we will be working with state regulators to actually close them."
Culbert says she predicts that groundwater assessment will be completed in 2015, at which point Duke will move forward with a closure plan for its coal basins.