Raw sewage spilled into Columbia's three major rivers and Lake Murray on Wednesday as the remnants of Tropical Storm Ida soaked Columbia and overwhelmed wastewater treatment systems.
The S.C. Department of Health and Environmental Control was posting signs warning of bacteria pollution where needed along stretches of Midlands waterways, including the Congaree, Broad and Saluda rivers.
Agency officials urged the public not to kayak, canoe or swim in areas where they see warning signs. The signs are to be left up until bacteria are considered at safe levels.
Harry Mathis, who heads the agency's local district office, said the sewage spills involved line breaks as well as failures from pump stations and sewage treatment plant overflows.
Wastewater systems run by the city of Columbia, the East Richland district, the town of Chapin and EA Services, a private company, had spills, according to DHEC.
DHEC did not have an estimate of how much sewage spilled, but Wednesday's leaks were significant enough to bring some agency employees to work on Veterans Day, a state holiday.
"Considering the amount of rainfall we've had and the short period of time that it has come, this has simply overloaded the systems," agency spokesman Thom Berry said, noting that some leaks are in "part of the collections system, where lines have backed up and (sewage is) coming out of manholes. Others are at the wastewater plants."
It wasn't clear whether sewage had spilled from the Broad River into the Columbia Canal, a source of Columbia's drinking water.
The Columbia area received about three inches of rain from early Tuesday to midday Wednesday, but the amounts were higher - from four to six inches - in the Chapin-Little Mountain area. The rain was so heavy that water poured into the sewer system and caused a pump station to overflow into Lake Murray at Murray Lindler Road, town officials reported.
"This is the biggest one I can remember," Chapin Mayor Stan Shealy said of the rain. "It filled up (the sewers) faster than they could empty."
Sewer overflows often occur in older systems when rainwater washes into pipes, causing contaminated water to leak out of the wastewater lines, manholes and through sewer plants. Too much water can make it harder for sewer plants to treat wastewater before discharging to rivers. The Columbia area has been plagued by a number of spills in recent years from aging pump stations and pipes.
The rainfall was enough Wednesday for the National Weather Service to issue flood warnings for the Congaree River at Sandy Run, downstream from Columbia. The forecast calls for a 40 percent chance of rain today before the weather clears Friday.
Spills like those Wednesday have likely occurred in the past, but people didn't know about it, one river protection advocate said. DHEC is now doing a better job warning the public of the dangers, said Charlene Coleman, a representative of the recreational group American Whitewater.
She attributed DHEC's improved warnings to a river conference last year that heightened awareness of threats to Columbia's rivers.
"Before, nobody cared to tell us and nobody was listening to us," Coleman said. "Now, it is being monitored better."
The conference came after a major spill into the Saluda from a private treatment plant during the summer of 2008.
John Dooley, public utilities director in Columbia, said spills in the city this week came mostly from overflowing manholes. The city did not have a spill from its 60 million-gallon-per-day wastewater treatment plant, he said. But the facility, which typically operates below capacity, was full Wednesday because of the excess rainwater. Dooley said workers were forced to divert excess water to a holding basin, which prevented a spill into the Congaree.
Specifically, city sewer overflows were found at five locations in Columbia:
- The 5000 block of Brickyard Road, which caused sewage to run into Crane Creek
- The 5900 block of Monticello Road, which also sent sewage into Crane Creek
- The 4200 block of Timberlane Drive in the Rosewood Drive area, which pushed sewage into Gills Creek
- The end of Saluda River Trail in Lexington County, which sent sewage into the Saluda River
- The 100 block of Wheat Street, which sent sewage into the Congaree. This section of Wheat Street is near the river
"When it rains hard, we know we're going to have a certain amount of this," Dooley said.
He said Columbia is studying ways to reduce such leaks.