Elevated bacteria counts lead to no-swim advisory after Catawba River sewage spill

Elevated levels of bacteria in Paw Creek Cove led to a “no swimming” advisory for the cove after nearly 850,000 gallons of raw sewage spilled into the Catawba River on Friday.

Water tests over the weekend found elevated levels of E. coli bacteria in the cove, Rusty Rozzelle, program manager for Mecklenburg County water quality, said Monday.

The advisory, issued Sunday, is likely to stay in effect until the end of the week.

E. coli is a bacteria that can cause illnesses such as diarrhea, urinary tract infections and respiratory problems. It’s one of many potentially dangerous microorganisms often found in raw sewage.

“People should not swim in the water for the next few days until the bacteria count has come down,” Rozzelle said.

Water-quality officials plan to test the water again on Wednesday to see if bacteria levels have declined enough to make swimming safe.

A construction crew was working at a Charlotte Water sewage lift station near Old Dowd Road, in western Mecklenburg County, when the spill occurred. Charlotte Water has said the spill occurred because of a pipe alignment problem that has since been repaired.

Charlotte Water and the contractor are reviewing what happened and discussing how to prevent it from happening again, said Cam Coley, a spokesman for Charlotte Water.

The spill is unlikely to affect drinking water in Charlotte, whose main water source is upstream on Mountain Island Lake. Downstream towns Fort Mill and Rock Hill, S.C., reported that their drinking water has not been impacted by the wastewater overflow.

Apart from bacteria and other pathogens, sewage is also full of the nutrients nitrogen and phosphorus. Too many nutrients in bodies of water can cause algal blooms and eutrophication, which is characterized by excessive plant and algal growth that can rob water of oxygen and lead to fish kills.

Given the size of the Catawba River, eutrophication is unlikely to be a big issue after this spill, Catawba Riverkeeper Brandon Jones said.

Last week’s incident was among at least four significant sewage spills by Charlotte Water in the past three years, according to utility reports. Previous spills included one of 15 million gallons in 2018, another of more than two million gallons that same year, and two million gallons in 2020.

“The three largest spills were all caused by heavy storms eroding creek banks causing pipe collapse,” Coley said in an email.

“A lot of it is old, aging infrastructure,” said Jones, the riverkeeper. “If you look at the number of spills they have per mile, Charlotte Water stacks up pretty well. The problem is, they are moving so much waste, when they have a spill, it can be extremely large, and a lot of their pipelines are on drinking water reservoirs.”

From mid-2019 to mid-2020, Charlotte Water reported 151 sewer overflows across the seven wastewater treatment plants owned and operated by the utility, a decrease of 11 spills compared to the year before, according to a 2020 report.

Most sewage overflows were attributed to debris, grease, and tree roots.

“A majority of wastewater overflows are caused by blockages and can be prevented with our customers’ help,” said Coley.

That includes not putting oil and grease down the kitchen sink and tossing only toilet paper in the toilet. Everything else should go in the trash or be recycled, he said.

This story was originally published July 19, 2021 at 6:09 PM.