Toxic algae blooms were identified at Hinckley Park in South Portland on Monday for the fifth consecutive year.
The cyanobacteria blooms can cause stomach illnesses and rashes for people who digest them or come in contact with them, and they can be fatal to dogs. The city is urging people to stay out of the ponds at the park and keep their dogs from drinking the water or swimming in it. Warning signs have been posted at the park, a popular dog-walking spot.
“All we really do is the same year after year now,” said Kristina Ertzner, the city’s conservation manager. “We can’t stop people from letting their dogs swim or drink, but we want them to be aware (the danger) is there.”
The blooms travel across the water due to wind, so part of a pond free of algae one day may not be on another, said Fred Dillon, South Portland’s stormwater program coordinator.
A number of factors can cause the blooms, he said, and the city is monitoring the water quality and trying to determine the primary catalyst.
“Forms of pollution that could be driving the algal growth could be from eroding soil, could be from dog feces that are left on the ground, and it could be from other upstream sources, like a failing septic system or something like that,” Dillon said in an interview at the park on Tuesday.
While the latter would be the toughest scenario to cope with, city staff, residents and parkgoers can mitigate the impact of human-influenced erosion and dog waste.
Last year, the Parks, Recreation and Waterfront Department planted native vegetation along a 450-foot stretch of the shoreline at the lower pond at the park. The plants filter runoff and help the soil stay put rather than slipping into the pond due to wind, rain or people and dogs walking over it. Temporary fencing was installed around the restoration area to prevent human and dog traffic.
“It’s really important for people to stay on the trails and stay away from areas wherever there’s bare, eroding soil, so they don’t make the problem worse by just stomping the life out of the plants that are trying to stabilize and hold onto the soil,” Dillon said.
Park rule changes in recent years have helped keep people and dogs on the trails and out of vulnerable areas of the shoreline, Ertzner said, but the restoration process isn’t quick.
“It’s something that will just take years,” she said.
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