North Carolina’s record floods could have unexpected environmental consequences

Local Riverkeepers worry that high water could lead to flooded coal ash ponds and hog manure lagoons.

Rising waters from the Neuse River threaten to inundate an inactive coal storage pond (left) at the Lee coal-fired power plant in North Carolina. CREDIT: Travis Graves, Lower Neuse Riverkeeper, Sound Rivers
Rising waters from the Neuse River threaten to inundate an inactive coal storage pond (left) at the Lee coal-fired power plant in North Carolina. CREDIT: Travis Graves, Lower Neuse Riverkeeper, Sound Rivers

Hurricane Matthew swept across the southeastern seaboard of the United States this weekend, bringing intense rainfall to North Carolina and triggering record flooding across much of the state. But as the rains subside and clearer weather rolls in, some environmentalists are raising alarm bells about the potential for yet another environmental disaster.

Over the weekend, Hurricane Matthew — which had been downgraded to a tropical cyclone by Sunday — brought as much as 18 inches of rainfall to parts of North Carolina, causing rivers across the state to reach dangerously high levels. The record-breaking floods have already damaged thousands of homes and left thousands of residents stranded. The state also suffered the highest number of causalities in the U.S. from the storm— nearly half of the 23 people killed lived in North Carolina.

As of Tuesday, the rains have stopped and forecasts look clear, but North Carolina residents could see more repercussions from the record-high water levels: Environmentalists in the state are warning that cresting rivers have the potential to flood facilities storing animal waste or toxic coal ash, potentially sending those waste products into rivers and groundwater.

“When we reach this point, when the flooding is already occurring, there isn’t much we can do other than try to encourage people to leave the floodplains and assist people where they need assistance, but we can’t do anything to stop the flooding now,” Travis Graves, Lower Neuse Riverkeeper with the Carolina Waterkeeper Alliance, told ThinkProgress. “This is all the result of decades of bad policy.”

North Carolina government officials released a statement Sunday assuring residents that they did not think a breach of coal ash storage ponds was likely. Still, they sent state environmental officials to two Duke Energy coal ash facilities — one of which contains two inactive coal ash storage ponds — to assess the impact of flooding. Aerial imagery released by Waterkeeper Alliance show some inactive coal ash ponds currently underwater, however, with others very close to rivers that are expected to crest in the coming days.

Aerial imagery taken of the Lee coal-fired power plant in North Carolina. CREDIT: Travis Graves, Lower Neuse Riverkeeper
Aerial imagery taken of the Lee coal-fired power plant in North Carolina. CREDIT: Travis Graves, Lower Neuse Riverkeeper

“We’re really in very, very good shape. The whole region is underwater, and the great news in this is the ash basin system is performing very well,” Paige Sheehan, Director of Policy and Environmental Communications at Duke Energy, told ThinkProgress. “There’s not a significant risk of coal ash being released from either site.”

Coal ash, the byproduct of burning coal for power, contains toxins like arsenic, mercury, lead, and other heavy metals, and is often stored in unlined pits known as storage ponds. These unlined pits can leach toxic material into groundwater, but also pose a threat to nearby communities and water bodies if they are breached, or the dikes holding back the toxic slurry of coal ash fail. That’s what happened at the Kingston Fossil Plant in 2008, when a dike failed and 1.1 billion gallons of coal ash spilled into a nearby river in what became the largest coal-ash spill in U.S. history.

As of 2014, Duke Energy, the state’s largest energy provider, had some 107,889,000 tons of coal ash stored at 32 ponds across the state.

But coal ash isn’t the only waste product that North Carolinian industry stores in massive amounts — the state is also the second-largest producer of pork and third-largest producer of chicken in the country, and, by extension, home to massive amounts of animal waste.

Animal waste is often stored in the same manner as coal ash — namely, it’s mixed with water and stored as a kind of slurry in pits which are often unlined. And as with coal ash, these unlined pits can do more than simply leach nutrients— and the nitrogen and phosphorus and bacteria therein — into ground water; they too can rupture and flood. In 1999, rains from Hurricane Floyd caused animal waste lagoons to overflow, spilling into rivers and threatening water supplies.

According to aerial observations taken by Graves and other Riverkeepers, several North Carolina hog farms have already flooded throughout the state. Dozens of other farms appear to be in the path of rising floodwaters, and could be inundated when the rivers and creeks crest later this week.

Aerial images of hog farms either flooded (above) or threatened by rising waters. CREDIT: Rick Dove, Waterkeeper Alliance
Aerial images of hog farms either flooded (above) or threatened by rising waters. CREDIT: Rick Dove, Waterkeeper Alliance

Many of North Carolina’s hog farms are concentrated along the state’s flat, low-lying Eastern coastal plain, making them especially prone to flooding. According to Graves, 170 industrial farming facilities are located within North Carolina’s 100-year floodplain.

The flooding that followed Hurricane Floyd was a 500-year flood event; officials have said that if the flooding associated with Hurricane Matthew follows the pattern of flooding that occurred with Hurricane Floyd, as expected, this most recent flooding would also qualify as a 500-year flood event. That would mean the state has seen two 500-year floods in the last 20 years.

“Those [flooding events] don’t add up to a good outcome anywhere you are, especially in an area that is already struggling with excess nutrient pollution,” Graves said.

A study published recently in the Proceedings of the National Academy of Sciences found that dangerous flood events caused by increased storm surge, like the floods that followed Hurricane Sandy, are likely to become increasingly common by the end of the century.

For places like North Carolina, that means the chances of toxic waste spilling from any of its hog waste lagoons or coal ash ponds is only going to increase — at the same time as the technology for those storage sites is becoming increasingly outdated.

“Advocates in North Carolina have been working for years, sometimes decades, trying to get the coal ash cleaned up, trying to get these antiquated waste lagoon systems replaced with better alternative technologies with are available but unfortunately the legislature has been very kind to industrial meat production in North Carolina and very kind to coal-fired power generation,” Graves said.

Update: This story has been updated to include a comment from Duke Energy.