Hurricane Florence may have barreled through the state this weekend, but the storms effects could be felt long after it had passed. On Sept. 18, the North Carolina Department of Environmental Quality reported that four lagoons suffered structural damage from flooding and 10 others were overflowing, causing manure to escape. There are 3,300 lagoons throughout the state.

Ahead of the storm hog farm operators had tried to dry out these lagoons before they got any chance to flood and contaminate local rivers and water sources.

A history of manure and storms

Hog waste lagoons are exactly what they sound like: They're man-made pits of hog waste that are basically over-sized compost heaps. Pig waste is pumped into them, bacteria breaks it down and that concoction is then sprayed over crops as a fertilizer. It's cost-efficient way to handle the sizable amount of waste the pigs generate.

These waste lagoons also pose an environmental hazard during hurricanes. Heavy rains can flood the pits, causing the walls of the pit to collapse and allowing the contents of the pits to get carried off by the floodwaters.

Farmers and environmentalists have been here before. Another hurricane, Hurricane Floyd, dropped nearly two feet of rain on North Carolina in 1999, flooding the waste lagoons. The overflowing waste lagoons flowed downstream and the waste found its way into coastal estuaries where it boosted nitrogen and phosphorous levels, causing algae blooms and fish kills, according to The Washington Post.

A few years later in 2016, Hurricane Matthew flooded about 14 hog farms. The damage caused in 2016 was much less severe than in 1999 since farmers had taken action to pump the lagoons as dry as possible before the storms arrived.

Florence and hog waste

A hog waste lagoon in Pennsylvania Lagoons are a cheap way to handle waste and create fertilizer for crops. (Photo: U.S. Department of Agriculture/Flickr)

AgWeb reported that Hurricane Florence could do the same kind of damage as Hurricane Harvey did in Texas last year, and the rainfall predictions were already drawing comparisons to Hurricane Floyd.

"Floyd did dump over 20 inches of rain across eastern North Carolina," meteorologist Brad Rippey of the U.S. Department of Agriculture (USDA) told AgWeb. "One of the biggest impacts was the mortality of tens of thousands of hogs and pigs and that also overran waste ponds. And so there was a lot of water pollution that got into the waterways through eastern North Carolina. Not to mention the tens of thousands of dead animals that producers are trying to deal with. So that is one target zone there in eastern North Carolina."

This year, the North Carolina hogs are safe, according to NPR. The hog houses are protected from flooding, but farmers may need to get to them by boat. With the hogs hurricane-ready, the focus turned to pumping the waste lagoons and spraying the fertilizer before Florence arrived.

Flooding is still a concern, however. Speaking to experts from North Carolina State University, NPR reports that the lagoons should be able to handle up to three feet (0.9 meters) of rain, a point reinforced by Andy Curliss, CEO of the North Carolina Pork Council. Curliss told Time magazine the pits can handle 25 inches (61 centimeters) of rain. ABC News reports that as much as 40 inches of rain could fall in the area.

Farmers are less sure than the experts about how this particular math problem will work out. Marlowe Vaughan of Ivy Spring Creek Farm in Goldsboro, North Carolina, told NPR she was pumping as much as waste as she could before Hurricane Florence arrived, but that she and other farmers were "kind of at the mercy of the storm."

"We have no idea what's going to happen. So everybody's very worried and very concerned. Please pray for us!"

Editor's note: This article has been updated since it was originally published in September 2018.

Flooding from Hurricane Florence causes hog waste lagoons to overflow
The overflow of manure can have a serious impact on surrounding waterways.