WINDHAM — Officials are closing the town beach at Cobbetts Pond next week for milfoil treatment.
It’s unclear whether elevated fecal bacteria levels that turned up in state testing Monday will force them to close it sooner.
Recreation coordinator Cheryl Haas said she is leaving the beach open for now because the town’s own testing last week showed bacteria at a normal level.
“I will be retesting (today),” Haas said.
State environmental officials expected to retest today, too.
Haas speculated the state’s numbers could be higher than the town’s because the state test happened on a day with heavy rain, which increases storm runoff and can affect readings.
Although she wasn’t closing the beach, Haas intended to post the state’s advisory so citizens would be aware. The state also put out an advisory.
Meanwhile, state and federal environmental officials plan a survey next month to evaluate trouble with another invasive species, a spreading population of Asian clams.
Haas said the beach will be closed Monday, reopening 11 a.m. Tuesday.
“We can’t let people in the water,” Haas said.
The treatment depends on weather, so it could be postponed if there is heavy rain.
Amy Smagula, coordinator for the state Department of Environmental Services’ exotic species program, said the herbicide treatment doesn’t pose a health concern.
The closure is safety related, required to keep swimmers away from boats as workers treat the pond, she said.
The milfoil treatment program, costing about $16,000, will be funded by a combination of a state grant totaling $6,350, matched with local money raised through shorefront property owners.
“This is the same issue we’ve had. We’ve been treating for years,” said Derek Monson, vice president of water quality with the Cobbetts Pond Improvement Association.
Milfoil, an aquatic weed, is not native to the pond, but likely was brought in by a boat years ago, then spread throughout the pond.
Monson characterizes the pond’s milfoil problem as up and down. “It’s a difficult problem to manage,” he said.
Cobbetts Pond covers move than 300 acres.
“We are treating 33 acres this year for milfoil,” Monson said.
“There is enough milfoil to warrant herbicide treatment,” Smagula said.
Other milfoil will be hand pulled by divers.
Asian clams are another concern for water quality.
They have been in the pond for a couple of seasons, but can spread rapidly. A single clam can release 2,000 to 8,000 offspring a year.
“They are pretty much around the pond at this point,” Smagula said.
State and federal officials plan a survey next month that could lead to a management plan, she said.
The clams, about the size of a dime, can contribute to algae blooms, compete with native aquatic species, clog water pipes, and injure swimmers and waders with their sharp shells.