Maps released by Duke Energy outline extent of damage if coal ash storage fails again

This map illustrates homes near Duke Energy's Marshall plant that would not only be flooded but also cut off to road access if the utility's coal ash lagoons failed. (© Duke Energy)

Flooded homes, washed out highways, contaminated drinking water – these are just some of the possibilities if another Duke Energy coal ash spill were to occur. Residents and regulators now have a clearer picture of the extent of the possible damage after Duke Energy, in response to legal action taken by SELC on behalf of our clients, released previously-redacted maps outlining the expected impact if another coal ash spill were to occur at one of Duke Energy’s sites.

“Now we know what Duke Energy was trying to hide,” said SELC Senior Attorney Frank Holleman. “Duke Energy’s dangerous coal ash lagoons threaten families, houses, property, lakes, and rivers throughout North Carolina if they fail. A wall of coal ash and polluted water could pour out of lagoons into neighborhoods and water supplies, flooding houses, businesses, roads, and highways. Duke Energy should not impose these risks upon families and clean water. Duke Energy needs to move all its coal ash to safe, dry, lined storage where it will not pollute and cannot harm North Carolina’s families and drinking water.”

Such emergency planning maps are required for all coal ash storage sites in the country, but Duke Energy was the only utility in the nation to black out the flood information and withhold the maps from the public. The withheld maps led SELC to file 10 notices of intent to sue for sites across North Carolina. Two days after the notices were sent, Duke Energy said they would release the maps, which were finally made public more than two weeks later.

SELC has since reviewed the maps, with key findings below.


According to Duke Energy’s map of flooding following a dam failure at its Allen coal ash site, coal ash would extend 20 miles along the Catawba River and into Lake Wylie, reaching a maximum depth of 10.5 feet, and flood 55 homes. Duke’s maps missed that coal ash would also flood Fire Station #38 Marina, part of the Charlotte/Mecklenburg Fire Department.


According to Duke Energy’s map of flooding following a dam failure at its Cliffside coal ash site, coal ash would extend 20 miles along the Broad River, reaching a maximum depth of 18 feet, and flood 27 homes. SELC analysis also identified that coal ash would flood a City of Gaffney’s drinking water intake 13.8 miles downstream, which serves almost 33,000 customers. Similarly, SELC’s analysis shows flooding of chemical wastewater ponds for Milliken Chemical and Magnolia Finishing Plant.


According to Duke Energy’s map of flooding following a dam failure at its Marshall coal ash site, coal ash would flood miles of Lake Norman shoreline and extend into the lake a few miles, reaching a maximum depth of 5.5 feet.

Maps show coal ash would flood 46 homes and residents on two peninsulas would be cut off from the mainland.

Lake Norman contains drinking water intakes for Morresville, Lincoln County, and Charlotte/Mecklenburg County. Of these three drinking water intakes, Morresville is the closest to the Marshall Coal Ash Basin.

Belews Creek

According to Duke Energy’s map of flooding following a dam failure at its Belews Creek coal ash site, coal ash would flood over 27 miles of the Dan River, causing waters to rise as much as 33.6 feet. The Dan River in Stokes and Rockingham County; Little Belews Creek; Town Fork Creek and other tributaries of the Dan River would be flooded. Maps show coal ash would flood 88 homes, churches, and businesses in areas such as Walnut Cove, Pine Hall, Madison, Eden, Mayodan, Stoneville, and Stokesdale. SELC analysis discovered coal ash would flood the City of Madison’s drinking water intake downstream that serves a population of 2,787. The inundation maps stop just short of the Eden, NC which also relies on the Dan River for drinking water. Also of note, a Norfolk Southern rail line passes just below the dam on Little Belews Creek, next to the Dan River.


According to Duke Energy’s map of flooding following a dam failure at its Mayo coal ash site, coal ash would flood waterways, as far as 23 miles downstream, including Cructhfield Branch, Mayo Creek, Hyco River, and the Dan River arm of Kerr Lake, reaching a maximum depth of 25 feet. Kerr Lake is a drinking water reservoir for people in both North Carolina and Virginia.


The Duke Energy maps posted for Roxboro are stamped 2010, whereas other maps provided for other North Carolina coal ash sites are stamped 2016. A dam failure at its Roxboro coal ash site would result in coal ash flooding much of Hyco Lake. The lake is a popular regional recreation area, with multiple boat ramps, a water skiing course, dedicated swimming areas, and numerous docks. Fishing tournaments are held on Hyco Lake throughout the year. 

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