UPDATE: The warning has been lifted as of Friday afternoon.
The Maryland Department of Natural Resources and the Frederick County Health Department are warning people from swimming in the waters at Cunningham Falls State Park.
Heavy rains Monday swept debris into the William Houck area of the park, according to a Facebook post from the natural resources department. Besides debris, the waters also have abnormally high levels of E. coli, said Laura Pfeiffer, a licensed environmental health specialist with the Frederick County Health Department.
When there is a lot of rain, E. coli levels in the water can spike, Pfeiffer said, but it is rare for it to happen in the Cunningham Falls swimming area. E. coli levels can increase as rains sweep stormwater, runoff and sewage into waters. The swimming area does not typically get much sewage because there are few septic systems around the park, she said.
It happened once last year, Pfeiffer added, around the same time, because of all the rain that fell over the summer. The water will clean itself, and health department officials tested the water again Thursday. Results will be released Friday, she said.
E. coli can lead to gastrointestinal discomfort and problems. But E. coli is just one concern following rain events. Other bacteria or viruses can cause gastrointestinal problems if swallowed or if it gets into a person’s eyes, Pfeiffer said.
It usually takes a couple days for the water to clean itself, Pfeiffer said, but that depends on how much rain falls.
“We seem to be having multi-day rain events in the last year or two so that can affect the water quality longer than a single rain event like this one was,” she said.
Water is tested every two weeks for E. coli for levels compliant with the Environmental Protection Agency. The high E. coli levels were found during a routine testing, she said.
Visitors to Cunningham Falls should check signage posted by the Department of Natural Resources to determine if the water is safe.