McCarrons beach remains closed due to E. coli

The beach at Lake McCarrons County Park was closed as of July 10 due to high levels of E. coli bacteria in the lake water, and will remain closed at least until July 24. (Mike Munzenrider)

Ramsey County closed its guarded beach at Lake McCarrons County Park on July 10, and according to a county official it could be closed for some time.

The county said in a July 11 press release that bacteria levels, specifically those of E. coli, were above recommended water quality standards and that the Roseville beach would open once bacteria levels were back down.

John Manske, the county environmental resource specialist who tests all county lakes Memorial Day through Labor Day, said as of July 18 that the Lake McCarrons beach was still testing too high and would be closed at least until July 24.

He explained that E. coli is used as a proxy to measure fecal matter in the water, and that the bacteria can come from any number of places. 

It can wash into the lake from beach sand, as organic debris, from leaky diapers or directly from swimmers, in polluted stormwater runoff, from sewage spills or sewer line breaks, from stream inflows or from wild and domestic animal waste.

When it comes to the county’s lakes, said Manske, goose droppings are a usual suspect. The closed beach and the grass above it, as observed July 15, were littered with the fowl’s waste.

Rain can wash the bacteria into lakes, he said, meaning the rainy start to the month is a likely contributing factor.

According to the federal Centers for Disease Control, E. coli infection can cause stomach cramps, diarrhea and vomiting, along with fever in some cases. The infection usually clears up in five to seven days and can be mild to severe, or even life-threatening.

“It’s more common that we close [a beach] than get a report that someone got sick,” said Manske, who estimated in his dozen years of being in charge of testing lakes that there’s one or two closures, max, any given summer.

Per standard guidelines, a beach closure can be triggered by one of two happenings: A single-sample spike in bacteria showing more than 1,260 organisms in 100 milliliters of lake water, or five samples equally spaced over a 30-day period that exceed 126 organisms per 100 milliliters of water.

Manske said a typical closure is based on a spike and only lasts a day or two.

“What we’re seeing in McCarrons is a prolonged elevated level,” he said, “so it’s unlikely that it will open up soon.”

Despite it’s temporarily high levels of E. coli, Lake McCarrons is considered to be one of the highest quality lakes in the metro, according to Bob Fossum, a water resource project manager with the Capitol Region Watershed District.

“The bacteria is a little bit different than some of the other water quality issues,” said Fossum, who points out that McCarrons has low levels of nutrients and phosphorus, which feed algae blooms. 

“It does have quite clear water for an urban lake,” he said.

Fossum said conditions for high levels of bacteria in lakes are just right, with lake water at its warmest for the year right now, good for bacterial growth. He said a number of other beaches in the metro have been closed for the same reason.

“It’s not a surprise,” Fossum said, “it’s unfortunate that it’s closing the [McCarrons] beach at the time that folks want to use it the most, but I think it’s not surprising.”


—Mike Munzenrider 

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