Minneapolis and three of its most populated suburbs in the west metro are urging people to keep themselves and their pets away from specific lakes over concerns about unhealthy levels of bacteria and potentially toxic algae.
The run of warnings issued in recent days covers beaches at Lake Harriet and Bde Maka Ska in Minneapolis, Lake Cornelia in Edina, Shady Oak Lake in Minnetonka and all public beaches in Plymouth.
These latest actions bring to at least 14 the number of swimming locales in Hennepin County under similar restrictions, according to a county tally and other official sources, and limits where relief can be found as the Twin Cities area temperatures crept into the 90s on Wednesday.
Plymouth’s sweeping action comes after testing revealed troubling levels of E. coli bacteria. Stomach cramps and diarrhea, along with skin irritation, are the most common symptoms of E. coli infections.
“Beaches will remain closed for the summer,” a statement Tuesday from the city read, noting that closed signs have been posted. That means no swimming or other aquatic recreation.
The city’s website lists three municipal beaches in Plymouth: Medicine Lake East, Medicine Lake West and Parkers Lake. Also closed is the French Regional Park Beach, which is operated by the Three Rivers Park District and is on the northern shore of Medicine Lake.
Water quality concerns from high levels of bacteria, such as E. coli, and other waterborne illnesses are typically caused by animal waste from geese and other waterfowl, and runoff into lakes after a heavy rain.
“It’s common to see more closures this time of year, especially after large rain events,” said Amanda Buell, supervising environmentalist with Hennepin County.
Randy Anhorn, administrator for the Nine Mile Creek Watershed District, said, “We’re see more algal booms in some lakes” thanks to a combination of “the heat we’ve had, calm conditions and rain events bringing [contaminants from] stormwater runoff. At many of our lakes, we are keeping an eye on it.”
Eric Mulek of Golden Valley stood ankle-deep with a paddleboard in a grassy area alongside Medicine Lake East and pointed out that the beach is a particular problem spot.
“There are always geese and ducks around there,” Mulek said. “I wait ’til I’m in the middle of the lake [before] I jump off.”
The Minneapolis Park and Recreation Board closed the beaches at Lake Harriet Southeast and Bde Maka Ska North on Tuesday after “E. coli levels exceeded state standards,” said Rachael Crabb, the Park Board’s water quality supervisor.
“This does seems to be a particularly bad summer for blue-green algae,” Crabb said. “It appears that others around the state have been noting poor conditions as well.”
To the west in Minnetonka, water testing at Shady Oak Lake on Monday indicated continued unsafe levels of E. coli bacteria, prompting the city to ban swimming in that body of water.
“We apologize for this inconvenience, especially during the hot weather, when a beach trip would be ideal,” a statement from the city read. “Your health and safety, though, are our primary concern. We’ll be in touch again as soon as we can reopen the lake.”
In Edina, the Nine Mile Creek Watershed District tested water samples from Lake Cornelia and found the potential for blue-green algae in numbers that exceed the World Health Organization threshold “for moderate probability of adverse health effects,” city officials said in a statement.
While visitors are not explicitly barred from Lake Cornelia, “the public is advised to have no contact with the water,” the statement continued, pointing out that blue-green algae can produce toxins that make people or pets ill if ingested.
Staff writer Katy Read contributed to this report.