The hydrilla menace: Lessons learned, shared in 2024 to aid in ongoing battle to safeguard lakes

“It’s a great group effort within this town, and everyone’s on the same page.”
– Bill Littauer, president of the Lake Wononscopomuc Association

SALISBURY — Lake association and town officials worked furiously in 2024 to address invasive hydrilla’s looming threat to lakes’ ecosystems, their management budgets and the local economy.

Of primary concern to the Twin Lakes Association last year was the discovery of the aggressive aquatic invader’s further spread in East Twin Lake as well as a projected 10-fold increase in lake management costs for 2025 and beyond.

“Everyone is scared to death about these expenses,” Grant Bogle, president of the TLA, said during the budget portion of the association’s annual meeting last August. “But here is the unfortunate news. It doesn’t go down next year or the year after that.”

The bulk of the responsibility for funding lake management, estimated at $350,000 in 2025, falls to the TLA, although the town of Salisbury is poised to contribute $100,000 for lake management which includes the cost of boat launch monitors at the marina. Other funding sources include fundraising and potential grants through the state Department of Energy and Environmental Protection.

Scare triggered rapid response

A noxious, fast-growing variant of hydrilla verticillata, referred to as the Connecticut River variant, was discovered in the summer of 2023 near O’Hara’s Landing Marina on East Twin and in the shallow waters north of the state boat launch, making it the first lake in the state known to become infected with the non-native plant.

The TLA, now entering its third year in the ongoing battle with the wicked water weed, immediately assembled a coalition of scientific and environmental advisers to address the threat.

The scare triggered a rapid response from other lake groups. The Lake Wononscopomuc Association, which oversees Lakeville Lake, issued a moratorium at the Town Grove boat launch which remains in effect until further notice.

Mt. Riga Inc. also played it safe by closing its Ostrander beach and campsites in 2024 until preventative measures were in place.

Last summer the TLA made sweeping changes to how it plans to safeguard water quality at East Twin and control hydrilla’s further spread. Those measures included boat inspections at O’Hara’s Landing Marina, blocking off passage under the Isola Bella Bridge and reverting the state boat launch to its initial mandate of providing access only to nonmotorized car-top watercraft.

In July, the first application of a slow-release herbicide, SonarOne, was applied at the marina and continued at three-week intervals throughout the summer, targeting hydrilla beds in the vicinity of the marina and in the north cove.

During this time, the TLA’s lake consultant, George Knocklein of Northeast Aquatic Research continued to document spread of hydrilla outside the approved treatment area.

In August, SonarOne was applied, with state approval, to the expanded treatment area in the marina and along the shoreline to the state boat launch.

In October, about 50 stakeholders attended a forum at the Town Grove during which Lake Wononscopomuc President Bill Littauer and TLA’s Bogle fielded questions and shared information and resources.

“It’s a great group effort within this town, and everybody is on the same page,” said Littauer.

Also last year, the U.S. Army Corps of Engineers targeted several field research demonstration sites where it tested various herbicides at coves and marinas along the Connecticut River impacted by dense infestations, the results of which have yet to be released.

With cautious optimism, federal, state and local officials working on managing hydrilla in the Connecticut River said they are starting to see encouraging signs.

The results of that testing, they said, will benefit not only the clogged coves and tributaries along the Connecticut River, but also other lakes, ponds and rivers throughout the state.

‘Far-reaching implications’

Attacking infestations with herbicides is only half the battle. Stopping reinfestations and spread to other waterbodies is key, said state environmentalists.

Public awareness is key to keeping hydrilla from spreading or reinfecting a waterbody because the wicked water weed can easily be transported from one lake or pond to another via unsuspecting boaters or owners of recreational watercraft.

For that reason, DEEP’s “Clean, Drain and Dry” program has been touted as a critical management component.

Looking to 2025, state environmentalists plan to spend the peak hydrilla growth period surveying 94 state-owned boat launches throughout Connecticut in search of hydrilla, according to Jeremiah Foley, assistant scientist and biological control specialist with the Connecticut Agricultural Experiment Station/Office of Aquatic Invasive Species.

Foley, who is a member of the Twin Lakes Association’s coalition of consulting experts, said the survey will include launches at lakes and ponds. He explained that it is likely that hydrilla is lurking in other lakes but has not yet been detected.

The scientist had warned in a May 2024 article of Invasive Plant Science and Management that the “discovery of Hydrilla verticillata and its subspecies lithuanica in the Connecticut River and the breadth of the current infestation represent a significant ecological invasion event with potentially far-reaching implications.”