When Hurricane Dorian knocked out power to more than 270,000 South Carolina homes, those outages also shut down dozens of utility system pumps that keep raw sewage going where it needs to go.
Utility crews in Mount Pleasant and Charleston scrambled to connect some of the wastewater pumps to generators, but there were still 13 sewage overflows in West Ashley and half a dozen in Mount Pleasant as wastewater backed up, according to the utilities.
"We had about six minor spills where wastewater backed up and was coming out of manholes," said Mount Pleasant Waterworks General Manager Clay Duffie.
The water and sewer utility had 45 of 163 pump stations without power Friday and urged residents to limit toilet flushing, laundry and bathing. Without pumps working to move wastewater along, backups and spills can result.
“Hurricanes, for us, are always an electricity-related event," said Mike Saia, spokesman for Charleston Water System. "If you don’t have electricity, you can’t pump wastewater."
Saia said CWS had 13 wastewater overflows, all in West Ashley. Many involved less than 500 gallons — the threshold for reporting the spill to state regulators.
"We don't think any of the (overflows) will exceed 5,000 gallons," he said.
For both utilities, having dozens of pump stations without power meant that crews had to rush around, taking generators from one station to another.
“We’ll get there and our crews will bring generators, pump them down and move on to next one," Saia said.
The rush to keep the pumps working eased as utility crews restored electricity across the area.
Mount Pleasant Waterworks has nearly three dozen generators but had 45 pump stations down on Friday. Duffie said it would cost $15 million to have enough generators for all 163 pump stations.
In Mount Pleasant the problems were concentrated in the southern end of the town. Mount Pleasant Waterworks warned Friday of potential impacts in and near neighborhoods, including: Hobcaw/Molasses Creek, Belle Hall, Shemwood, Remley’s Point, Copahee/Beehive/10 mile, Hamlin Plantation, Charleston National and Snee Farm.
Duffie said part of the problem the utility faced was that many residents did not evacuate for the hurricane, and continued to generate wastewater that flowed into a system with pumps out of commission.
“We’d like not to spill, but a lot of people stayed, and when we have power outages and a lot of people are in town … (they) use water and flush and do laundry like normal, and it puts a load on the system," said Duffie.