Pumping started Dec. 22, said Altamaha Riverkeeper Jen Hilburn, who discovered it after receiving a tip. Similar pumping in North Carolina prompted that state's regulators to find that Duke Energy broke state law in 2014 when it sent as much as 61 million gallons into a North Carolina canal that fed into the Cape Fear River. Members of Waterkeeper Alliance and other groups discovered the violation.
"Hopefully they'll have it (the ponds) to a level to where it'll be low enough for the rains," Hilburn said of Georgia Power. "My concern is these coal ash ponds that are held up by these rickety dams of rock and dirt are not sustainable in the long term."
The group and other environmental advocates say the safest way to store the coal ash is to move it away from rivers and lakes.
The ponds are built to withstand a 24-hour rainfall of 5.7 inches, according to a 2004 wastewater permit application for Plant Branch. Nearly 11 inches fell in December in Milledgeville. About 2.33 has fallen so far in January, according to the National Weather Service.