Heavy rains leave dangerous bacteria levels in some Charleston waterways

MOUNT PLEASANT, SC (WCSC) - Several days of heavy rain left dangerously-high levels of bacteria in multiple Charleston waterways, according to a recent report from Charleston Waterkeeper.

Charleston Waterkeeper, a non-profit organization that advocates clean waterways in the Charleston area, performs weekly testing of Charleston waters during peak swimming season.

The tests start in May and last through October.

Charleston Waterkeeper's newest test was published on Friday. The results indicated a portion of Shem Creek had high levels of bacteria in the water, meaning it is unsafe for people to swim.

According to South Carolina's water quality standard for water-based recreational activity, swimming is not recommended in water containing bacteria counts of 104 MPN/100mL or higher. Charleston Waterkeeper's most recent test indicated a bacteria count of 336 MPN/100mL in one portion of Shem Creek, more than three times the limit.

Previous reports show consistently high levels of bacteria in that same portion of Shem Creek.

"We typically find those high levels of bacteria after rainstorms," Charleston Waterkeeper spokesman Andrew Wunderly said. "So the general rule is the more it's been raining, the worse water quality is. The dryer it's been, the better water quality is. So that's a good rule of thumb for folks to keep in mind."

Of the six tests conducted in 2018, four weeks have indicated dangerously-high levels of bacteria.

Charleston Waterkeeper works with the Department of Health and Environmental Control and the Town of Mount Pleasant to regulate the quality of water in Shem Creek. Town officials say they are working toward putting together a plan that will target ways to reduce bacteria levels in the creek.

In 2017, Charleston Waterkeeper tested waterways for 26 weeks. Bacteria levels were too dangerous for swimming 20 weeks out of that time.

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