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Staff Writer | August 13, 2020 1:08 AM

Unusually thick pest annoys locals on the lake

A mystery from deep has emerged along the shores of Casco Bay, one that has local waterfront property owners perplexed.

“Each summer, starting around July, enormous amounts of seagrass pollution floats in and around Casco Bay and through our waterways,” Ken Belisle wrote in an email to The Press.

Belisle wasn’t alone in his curiosity. The Press has received multiple inquiries into the matter, some observing that the grass buildup — an annual clean-up tradition around parts of Lake Coeur d’Alene — has been more pronounced this year. The grassy debris that collects along the bay.

“I’ve seen quite a bit of it,” Willamina Barrett, who lives near Casco Bay, told The Press. “We had to pull quite a bit up last weekend. I know … it comes in every year, but it seems like a lot more this year.”

“My question is,” Belisle asked, “where does it come from, and is (there) something that can stop this? It is always an enormous amount of work to clean up this mess the last couple months of summer.”

The Press reached out to Jamie Brunner, lake management plan supervisor for the Idaho Department of Environmental Quality’s Coeur d’Alene office. She said she wasn’t surprised to hear about the grass buildup hitting Casco Bay this year.

“There are a lot of different plants that grow in the lake,” Brunner said. “That, and it’s also just that this time of year, plants are getting to their full length.”

When Brunner, a University of Idaho graduate with a degree in Environmental Science, was asked about an unusual buildup of grass, she speculated the unusually busy boat activity was churning up plant life at a faster clip than normal.

Brunner added that boat owners should be mindful if the grass that has washed ashore is milfoil. Milfoil is an invasive, feathery weed that grows in thick mats. It’s been the target of local environmentalists, citizen groups and even the Idaho Legislature in concerted efforts to eradicate the infestation.

“If it’s milfoil, pull it out and get it somewhere high and dry, where it can’t get back in the water,” she warned. “And you definitely want to get it off your boats, because it’ll spread.”


The yearly routine of homeowners along Casco Bay cleaning up excess grassy debris has become cumbersome this year, according to multiple homeowners. An overabundance of foliage is believed to be caused by unusually high boat activity, which has dredged up the grassy hassle at a higher rate this summer. (Photo courtesy of Ken Belisle)