A second stormwater pipe under a Duke Energy ash pond in Eden is in danger of failing, say state officials who ordered Duke to fix the problem Friday.
A 48-inch pipe under the pond broke Feb. 2, dumping up to 39,000 tons of ash into the Dan River.
Video inspection of a second, 36-inch pipe shows “it has the potential by configuration to release ash material in a way similar to the 48-inch conduit,” a state dam-safety engineer wrote Duke on Friday afternoon.
The N.C. Department of Environment and Natural Resources gave Duke 10 days to develop a plan and schedule to fix the second pipe.
“We’re concerned about the leaks we see in the 36-inch pipe and want to prevent a second pipe failure,” Tracy Davis, director of the N.C. Division of Energy, Mineral and Land Resources, said in a statement Friday night.
“We’ve asked Duke to provide a schedule for developing a plan and implementing that design to repair the pipe.”
Steven McEvoy, a state dam safety engineer, wrote Duke that videos of the reinforced concrete pipe’s interior showed it was laid in four-foot sections with numerous joints.
McEvoy noted water was dripping through a number of those joints. In three places the flow was under pressure, forming what the engineer called “water jets.” He also saw ponding water inside the pipe. One joint near the pipe’s outfall to the river had separated, he wrote.
The larger pipe that failed was made of reinforced concrete for about one-third its 1,000-foot length. The rest, including the section that broke, was made of corrugated metal, Duke revealed last week.
That pipe is being filled with grout to permanently seal it.