The Hudson Conservation Commission received encouraging news at its Oct. 19 meeting, learning that this year’s invasive aquatic plant treatments at Ottarnic and Robinson ponds were deemed successful, with no evidence of milfoil or other targeted invasive species found in the latest review.
The commission discussed the town’s ongoing invasive species management program, which combines herbicide treatments with diver-assisted suction harvesting to keep the ponds clear of invasive vegetation.
“Every other year, a company comes out, and they do something called diver-assisted suction harvesting, where they quite literally vacuum out invasive species from the ponds, and then they also apply herbicide to the ponds,” explained Civil Engineer Don Kirkland. “Some years it’s only one herbicide application, and some years it’s two, but this year Ottarnic got three: one in May and two in June. Robinson Pond had one in July and one in August.”
Results from the treatment program did not arrive until mid-October. According to Kirkland, a report from SOLitude Lake Management concluded that treatments at both ponds were successful, with no visible signs of invasive milfoil remaining.
The treatment effort represents a significant investment by the town, although half of the costs are reimbursed through state funding.
“Between April and just recently this month, SOLitude Lake Management has billed the town $57,430, of which 50% is reimbursed by the state, which will total $28,715,” said Kirkland. “To date, we have submitted three reimbursement requests, two of which have been paid, and we are awaiting payment of the others. There will be five reimbursement requests in total.”
With favorable results at both ponds, Commissioner Kathy Griswold asked whether it might be time to evaluate conditions at Musquash Pond and determine whether similar treatment strategies are warranted there.
“What was the trigger that got us treating the invasives in Ottarnic and Robinson ponds?” she asked. “Is it time to assess Musquash? We saw a significant number of invasives there.”
Vice-Chair Ken Dickinson explained that work on Robinson Pond dates back more than two decades, beginning with the formation of the Robinson Pond Association and later expanding into active treatment programs around 2010. Efforts at Ottarnic Pond followed through the cooperation of waterfront property owners, commission members, and state officials.
“Musquash should be addressed, or maybe not addressed, but at least evaluated to see where it falls within the realm of treatment,” admitted Dickinson.
Despite the good news regarding invasive plant management, commissioners noted that other water-quality issues remain.
A late-season algae bloom developed at Robinson Pond despite the successful treatments.
“It happened at the end of the season, after they already made very successful treatments, though it stayed relatively warm up until that point,” said Dickinson. “The report said it stretched from the boat launch to the beach.”
Town staff said they would continue gathering information about the bloom and its possible causes.
The commission also received an update on the long-discussed Robinson Pond boat launch project, which recently received grant approval.
“We have been approved for the grant to construct that boat launch,” said Kirkland. “The town, through a warrant article, approved $250,000, that’s the 50% match. The state also provided $250,000, plus $89,000 to cover half of the design. We fronted the money for the design, and we are getting reimbursed for that design and for the construction all at once through that grant.”
Officials hope the project will improve public access while reducing phosphorus runoff into Robinson Pond, helping to address future cyanobacteria and algae blooms. A request for proposals covering the boat launch, parking area, and stormwater treatment portions of the project is expected to go out in the coming weeks.
Commissioner Chris Cameron confirmed that construction is expected to begin next year.
“We’ll finally get a chance to do something physical after years and years of studies just to get to this point,” said Dickinson. “It’s nice to see something finally coming to fruition after it seems like we batted that idea around for such a long period of time.”
No completion date was announced for the project.
The next meeting of the Hudson Conservation Commission is scheduled for Monday, Nov. 9, at 7 p.m. in the Buxton Meeting Room.