The State Department of Environmental Conservation is taking a new approach to rid the Peconic River of Ludwigia, an invasive plant that has infested the freshwater portions of the river in Brookhaven and Riverhead towns.
Later this month the state for the first time will undertake the widespread application of herbicides to the invasive plant, which in some portions of the river has formed a dense mat on the surface of the water, negatively impacting the health of the aquatic ecosystem and interfering with recreational activities, according to the DEC.
Ludwigia peploides, also known as floating primrose-willow, is a federally listed noxious weed that, once established, is extremely difficult to remove. Ludwigia was first discovered in the Peconic River around 2003. Since that time, it has grown and spread throughout the freshwater part of the river. DEC staff and volunteers have been manually removing the plants each year for the past decade, investing more than 5,000 hours in the effort, which was “consistently ineffective,” the agency said. See: Peconic RIver Ludwigia Control Project page on DEC website.
Last year, the DEC, in collaboration with Suffolk County Conservation Advisory Council, Stony Brook University and U.S. Fish and Wildlife Service, conducted a pilot study of treatment methods for Ludwigia, testing the herbicide treatment in a small area (less than one acre) near the DEC’s Edwards Avenue canoe launch.
The pilot project was successful, the DEC said, and so the agency developed a five-year management plan for dealing with the Ludwigia infestation in the Peconic.
On July 7, the DEC’s deputy permit administrator for Region I (Long Island) approved five-year permits to allow the application of a combination of two systemic herbicides, ProcellaCOR EC (florpyrauxifen-benzyl) and Clearcast (imazamox) directly to the leaves of the plants.
The herbicide application will be done on a single day during the week of July 25 in freshwater portions of the Peconic where the infestation is dense, according to a DEC Region I spokesperson. Weather and river conditions will determine the exact date that the application will take place, she said.
Kevin McAllister of Defend H2O objects to the application of herbicides in the Peconic River. It will have negative environmental impacts that the DEC has failed to evaluate, McAllister said in a phone interview Thursday.
While DEC classified the treatment as a Type I action for purposes of review under the State Environmental Quality Review Act, the agency determined it will not have a significant adverse environmental impacts and dispensed with the preparation of an environmental impact statement. That was a mistake and a violation of SEQRA procedure, McAllister said.
McAllister said it’s folly to assume the herbicides will not disperse downstream and pose a risk to non-target plants and wildlife.
“The potential for collateral damage is real,” McAllister said. The manufacturers’ product labels acknowledge the risks posed, he said. The potential impacts should have been the subject of study, he said.
McAllister also said the DEC has a conflict of interest since it is both the sponsor and the permit reviewer. This “calls into question the ability to objectively evaluate environmental impacts,” McAllistar said.
McAllister argues that “antiquated dams” in the Peconic and other water bodies are causing impacts to the waterways.
“Take down the dams, restore some flow, release these organic sediments that are building up,” he said. “It’ll help control these invasives. Instead, we go after with these chemicals, and reinforce these dams that are archaic. It’s ridiculous.
He said government officials have no appetite for removing the dams due to “political considerations.”
The DEC disagrees. “Removing upstream dams or impoundments to increase the river’s flow rate would likely have little or no impact on the Ludwigia infestation,” the agency said in a statement.
“Slow-flowing and quiescent waters are not the cause of Ludwigia’s persistence and spread. During the time that Ludwigia has been present in the Peconic River, there have been several large storm events, including hurricanes, which increased the flow rate in the river,” the agency said. “Yet the Ludwigia infestation in the river remains.”
McAllister said he is also concerned about how the post-treatment plant die-off will affect the river’s dissolved oxygen levels. “A sudden and mass die-off of many acres of invasive plants would suppress dissolved oxygen levels in the river, stressing oxygen-dependent aquatic life,” he said.
Randy Wade, a West Main Street homeowner whose property is on the Peconic River, said she is very concerned about the possible impacts the herbicide application may have on fish, birds and plants — as well as health risks to people and pets.
“We homeowners received notice months ago and protested. I just received an email that our concerns are being ignored and it will proceed,” Wade told RiverheadLOCAL yesterday.
“The poison is strong enough that dogs are advised to stay clear and not drink contaminated water. You can imagine what that will mean for fish, waterfowl and other birds and the small mammals that live along the river,” she said.
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