State raises hazard classification at coal ash dams in Lumberton

Raleigh

RALEIGH – State officials have raised the hazard classification for two dams at Duke Energy’s coal ash ponds in Lumberton after new information from Duke revealed that a failure of either dam could put residents living downstream at risk or damage homes nearby.

State dam safety officials raised the classification for both dams at the Weatherspoon Steam Station to “high hazard,” the most serious of the three classifications. The classifications are used to measure the downstream damage potential if a dam breaches, but the classifications do not relate to the condition of a dam.

The classifications were changed by state Dam Safety officials after Duke Energy provided the state with emergency action plans that show that a failure of either dam could severely damage downstream property or endanger residents living in four homes near the Weatherspoon coal ash impoundments.

Earlier this year, the state requested the plans, which provide information about the potential impacts of a dam failure and how a response would be handled if an emergency occurred. The state requested the emergency action plans as part of its ongoing actions to address coal ash management after a Feb. 2 spill at the Dan River steam plant.

Changing the hazard classification to “high hazard” means both dams at the Weatherspoon facility will be inspected by state officials once a year and requires the utility to conduct periodic inspections as well. Dams with “intermediate” or “low” hazard classifications must be inspected once every five years. “Exempt” dams, which are under 25 feet high or impound less than 50 acre-feet in volume and are not classified as “high hazard,” are exempt from periodic inspections. Hazard classifications can change as new downstream hazards are developed or identified.

Dams are classified as “high hazard” if a failure would likely cause loss of life or serious damage to property or roads. Before the dams were reclassified, one of the dams at Weatherspoon was classified as “exempt” while the other was classified as an “intermediate” hazard. Dams classified as “exempt” are not considered to pose a threat to property or roads if they fail and are not under state regulation. “Intermediate” refers to dam failures that are not likely to cause loss of life but could cause property or road damage. The letters the N.C. Department of Environment and Natural Resources sent to alert Duke Energy of the state’s decision to raise the dams’ hazard classifications can be found at: http://bit.ly/1B9XIA1 and http://bit.ly/1nvMeyy .

State Dam Safety officials have received emergency action plans for all the dams at Duke’s coal ash storage ponds and are assessing whether to reclassify other dams based on information contained in those plans. If coal ash dam reclassifications are necessary, changes will be noted on the N.C. Department of Environment and Natural Resources’ “Dan River spill” webpage, http://portal.ncdenr.org/web/guest/dan-river-spill .

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