Duke Energy is currently working on improvements to two dams at the Belews Creed Steam Station ash pond to address existing seeps and provide better structural support.
Duke Energy spokesperson Zenica Chatman said the work began in July and will continue until the fall of 2016.
“One project relates to Pine Hall Road where we are going in and clearing out some vegetation and also going in and looking at pipe we grouted several years ago,” she said, noting the pipe in question is not currently being used. “There is nothing behind it. There is no water flowing to it. We are just checking the grout and repairing it where we need to do so.”
She noted that there may be lane closures on Pine Hall road in the coming weeks as a result of the work.
“We want to make sure we are minimizing the overall impact to the community and are keeping neighbors informed,” said Chatman. “We are working with DOT on the lane closures and will post the appropriate signage.”
The bigger project involves installing a weighted filler overlay on the ash basin’s main dam.
“We are going in and adding several layers of sand and stone and then an additional layer of top soil that will be vegetated,” said Chatman. “It will add another layer to strengthen the dam. It is all about improving our system. The overlay will serve a dual purpose. It add an additional layer of stability and strength, but it will also address seepage by redirecting those seeps back into the pond.”
She noted that the work was a result of increased attention to ash ponds following the Dan River spill, adding that the company was inspecting and upgrading facilities through out its system as well as increasing groundwater monitoring efforts.
“The ash basin at Belews Creek is operating safely, but we are always working to improve operations across our system, “she said. “We have between 30 and 35 identified seeps at this site. The total seepage volume at most sites is very small compared with the wastewater being discharged daily through normal outfall. For example Belews’s average daily discharge is 8.1 mgd with seepage at 0.2296 mgd (2.83%). Seeps generally occur at low flows and contain low levels of constituents.
“Dewatering and permanently closing ash basins will ultimately resolve the seeps,” she said. “In the meantime, we’re following a process directed in the new Coal Ash Management Act to identify, test and monitor seeps. We provided detailed data on seeps so state regulators can make informed permitting decisions. Our objective is to include seeps in the permits so we can follow the appropriate monitoring protocol or next steps regulators prescribe. Keep in mind that some seeps are natural seeps that may fluctuate based on rainfall, season and other factors. Other seeps included in these reports are engineered drains at the base of the dams that utilities install to route water away from dams.”
Chatman said Duke Energy had been monitoring groundwater at the site since 2007.
“Since the Dan River spill we have gone in and installed more groundwater monitoring wells across the fleet and about 63 new monitoring wells at Belews Creek,” she said. “They will provide some of the most comprehensive information about what is going on around our basin. Then we will get to groundwater modeling where we will look to see how the groundwater will move over time. The state puts all of that together to inform their process on when these basins are closed.”
She said the report on the Belews Creek ash basin would be submitted to the state on Sept. 9, but noted it would still be some time before a decision on how to close the basin, whether to move the ash to a lined landfill or to cap it in place, would be made.
“We are committed to closing basins safely in North Carolina,” said Chatman. “We continue to conduct science and engineering studies at the Belews Creek. The final decision will depend on DENR’s basin classification, which should be done by the end of the year, required by the CAMA that involves public input.”
She said once all of the studies have been completed then Duke would start to develop a site specific closure plan.
“We have released some closing recommendations for some locations, but Belews Creek could still be a candidates for either cap in place or excavation,” said Chatman. “We don’t have the science back right now to give that recommendation. As part of our closure planing process we look at groundwater and we look at the overall environmental impact before making any recommendation on a basin.”
She added that if the recommendation would be to move the ash from the existing facility, then Duke would use special trucks to minimize the impact of airborne dust.
Nicholas Elmes may be reached at 336-591-8191 or on Twitter @NicholasElmes.