Broken Duke Energy pipe was metal, not concreteFeb 5 - McClatchy-Tribune Regional News - Bruce Henderson The Charlotte Observer
Crews continued Wednesday to try to stop the flow from a leaking Duke Energy ash pond in Eden, but have made a surprising discovery. The stormwater pipe that broke Sunday under the 27-acre pond was made of corrugated metal, not the stronger, reinforced concrete that Duke had believed it to be. The discovery underscores how much remains unknown about what caused a break that washed 50,000 to 82,000 tons of ash down the Dan River with at least 24 million gallons of water. Duke officials had said that it was "definitely unexpected" that a reinforced concrete pipe would break. But crews that unearthed the pipe's break point learned that two-thirds of its length is corrugated metal and the third closest to the river is reinforced concrete, Duke spokeswoman Erin Culbert said Wednesday. "Knowing the material helps inform the engineers who are designing a permanent solution," she said. The pipe was installed in the 1960s, Duke says, before the ash pond was expanded and divided into two basins. The primary basin held 992,000 tons of ash, meaning that 5 percent to 8 percent of it was released. Culbert said the flow from the pipe into the Dan River decreased Tuesday but is still entering the river. She did not have an estimate of its volume. Donna Lisenby of the advocacy group Waterkeeper Alliance paddled the river late Tuesday afternoon and estimated the flow was five to six inches high in the 48-inch pipe. Duke said Wednesday that water samples show that routine treatment makes the water safe to drink. Danville, Va., which has the closest intake to the Duke power plant, has said it is able to filter out contaminants from the gray-tinted river water. Advocacy groups have criticized Duke for not publicly reporting the spill until a day after it was discovered, but a N.C. Department of Environment and Natural Resources said Duke obeyed state law. Duke has said the pipe break was discovered at about 2 p.m. Sunday. The company said it reported the spill to the environment department at about 6:30 p.m. Sunday. Department spokesman Jamie Kritzer said that met a legal requirement to notify state officials within 24 hours. Duke's press release on the spill, at 4 p.m. Monday, met a 48-hour requirement, Kritzer said. http://www.energycentral.com/functional/news/news_detail.cfm?did=31435917& |