Lake Iroquois’ unwelcome guest to be uprooted

Observer photo by Jess Wisloski A film of chopped-up milfoil, created by boat propellers, sits on the surface of Lake Iroquois.
Observer photo by Jess Wisloski
A film of chopped-up milfoil, created by boat propellers, sits on the surface of Lake Iroquois.

By Jess Wisloski

Observer staff

Anyone who’s been swimming or boating at Lake Iroquois this summer has seen the yellow, murky scum increasingly coating the surface of the water. Or noticed the slimy squish underfoot.

That’s the Eurasian Watermilfoil, an invasive species that’s been multiplying in Lake Iroquois since it entered the waterways at least a decade ago. And that’s when the Lake Iroquois Association formed, a local advocacy group dedicated to maintaining the watershed, made up of local residents and lakefront property owners. So far, they’ve had one main mission: battling the invasive species, known as ‘milfoil.’ And starting next week, they’re amping up the fight.

“The milfoil’s a big problem,” said Pat Suozzi, president of the Lake Iroquois Association (LIA). “It’s a problem in a number of lakes here in Vermont, and it’s particularly bad here, unfortunately. So we’re working on it.”

Observer photo by Jess Wisloski Swimmers play in the water July 27, in the cordoned off area at Lake Iroquois’ beach. In the distance, chopped-up milfoil sits on the surface of the lake.
Observer photo by Jess Wisloski
Swimmers play in the water July 27, in the cordoned off area at Lake Iroquois’ beach. In the distance, chopped-up milfoil sits on the surface of the lake.

The seaweed-like plant — very likely the same one you’re getting tangled in while swimming — which roots in the bottom of the lake, can grow up to 14 feet tall with enough light, and the problem at shallow Iroquois is, there is plenty of light.

The species likely first entered the lake from boaters bringing vessels that had been in Lake Champlain or other infested waters into Iroquois without being cleaned first, but the conditions seem prime for the proliferation of the stuff.

“There’s no one reason,” for its takeover of the lake, Suozzi said, “but what we know is it’s pretty bad and we need to do something. Because it’s an invasive, it proliferates. It will choke out native species, it will choke out fish as well, and it makes boating and swimming difficult, if not impossible in some places.”

Dan Sharpe, a Buffalo-based attorney who spends summers in a home on Lake Iroquois, said the especially pernicious thing is how the weed manages to invade both the underneath and the surface of the water, all the while looking to take root again.

“Where it’s really thick [is] in the north end of the lake, which is really quite shallow, so the milfoil is quite thick,” he said. “Motor boats — propellers — are the things that chew up the milfoil, they cut it as it goes through, and that chops up all this milfoil. That then floats to the surface and gathers all around the lake,” he said. “Sometimes if you’re out here, and you’re looking, you can see it’s all over the surface of the water. That’s actually chopped up milfoil.”

“It sits in the water for a while, and then you can see the roots growing off of it. Those pieces like to get to someplace shallow, they’ll sink to the bottom and take root,” Sharpe explained. “That’s really how it spreads…it’s spread primarily by boats,” he said.

In the coming weeks, the Lake Iroquois Association — which until now has focused its work on prevention and education measures — is taking its work a step further by pursuing active removal of the plant.

On Monday, the association will have AB Aquatics, a private contractor out of Henniker, N.H., working across the lake do something called diver-assisted suction harvesting, or DASH, in hopes of cutting back on some of the spread of the weed that’s covering the lake’s floor.

Sharpe said the association had investigated various remediation efforts, and saw Lake Dunmore, near Brandon, had success with the technique. “Two of us went down [there] which is a fascinating thing, to get on board one of their suction-harvesting boats that they operate in the summer.

“So that’s one method. Actually pulling up milfoil by the roots and taking it out of the lake. It doesn’t use chemicals; it’s pretty benign, and because you’re removing the plants, which store phosphorus, you’re removing some phosphorus from the lakes when you take them out.”

Sharpe pointed out that phosphorus can contribute to making a satisfying, nutrient-rich environment in the water that might be favorable to milfoil.

Boats will be on the water from Aug. 8 to 19, and association members and residents will be able to see a demonstration of the suction-harvesting efforts about midway through the work, Suozzi said. All the fees collected by the LIA go towards paying for the boats as well as other efforts to keep invasives at bay, including boater and resident education on invasives, are establishing a greeter program at the boat launch, where staff keep contaminated boats from entering the water before they’ve been cleaned off, and soon a boat rinse station.

“It looks like we’ve stopped it from increasing. The trick now is to get it to decrease,” said Suozzi.

She and Sharpe noted that there are other efforts that can be taken, but there’s not a lot of funding to help pay for it. The greeter program and DASH boats were funded in part by an Aquatic Nuisance Control Grant, from the state, but that any contributions were much appreciated, and that the local communities didn’t have the resources to help fund much work.

“We’ve got some grant funding, we have fundraising, we have membership dues and we’ll be doing a lot more active fundraising so we can continue to fund this work,” said Suozzi. “It’s hard, it’s very, very expensive to fight invasives; it’s a very expensive proposition. So we welcome donations to the Lake Iroquois Association,” she noted. “All donations go to fighting the milfoil.”

Whether the suction boat will be able to make a dent in the milfoil epidemic is another question, though. Sharpe said the LIA shared differing opinions on how further to improve the milfoil situation, and that possibilities may range from dumping chemicals into the lake to kill it off, to working on monitoring and keeping clean the tributaries that feed into the lake.

“If you can get that water to be cleaner, then what’s in here, the lake flushes itself. Then you can actually lower the phosphorus level or nutrient level in the lake,” Sharpe said, noting that this approach, which he favors, would be costly, but could have a longer-term positive impact.

Residents who wish to learn more about the milfoil crisis at Iroquois or to join the association can visit or email