Hydrilla threat prompts new prevention plan at Lake Waramaug

“We’ve been very lucky, but we don’t want to press our luck.” — Dean Sarjeant, Lake Waramaug Authority

WASHINGTON, CONN. — Town and lake officials are exploring plans to install an additional boat decontamination station about two miles from Lake Waramaug’s public boat launch as an aggressive strain of the invasive aquatic plant hydrilla spreads through Connecticut waterways.

The proposed station, which would likely be located at the New Preston firehouse, is designed to intercept boats before they reach the lake and would supplement the inspections already conducted at the public boat ramp.

The proposal is aimed at preventing the plant from reaching Lake Waramaug, one of the state’s largest natural lakes and a popular destination for boating and recreation in Northwest Connecticut.

Concern about hydrilla intensified locally after the plant was discovered four years ago in East Twin Lake in Salisbury, where monitoring and costly treatment efforts continue.

The latest plans were discussed on March 5 during an informational question-and-answer session at Bryan Memorial Town Hall in Washington Depot, which drew about 40 participants via Zoom and about a dozen attendees in person, including town officials from surrounding towns.

Questions from participants focused on the cost of the watercraft sanitization project, its location away from the New Preston boat launch and the reason for operating two separately staffed inspection locations.

The hour-long session focused on preventative measures to keep hydrilla out of Lake Waramaug, which is bordered by Washington, Warren and Kent, and is the state’s second -largest natural lake.

Gregory Bugbee, associate scientist at the Connecticut Agricultural Experiment Station and an expert on invasive aquatic plants, served as the event’s guest speaker. Sean Hayden, executive director of the Lake Waramaug Conservancy, introduced Bugbee, noting that the state aquatic plant expert would “set the stage for what we’re concerned about when it comes to hydrilla.”

Aggressive hydrilla
strain spreading

Bugbee said that the state has been tracking hydrilla since 2016, when an aggressive subspecies was discovered in the Connecticut River.

The strain — Hydrilla verticillata ssp. lithuanica — traces its origins to Lithuania and has proven particularly aggressive in northern climates.

Bugbee said the plant was discovered in East Twin Lake in Salisbury in June 2023 near O’Hara’s Landing Marina.

“As far as we knew, it was not in any other place, but that all changed quickly when it spread to other waterbodies in Connecticut,” Bugbee said. “We think it spreads primarily by watercraft at boat ramps.”

To illustrate the threat, Bugbee showed a slide of one of his survey boats nearly engulfed by hydrilla in the Mattabesset River. “We are very much worried this is going to be the condition of other lakes if hydrilla is not stopped.”

According to Bugbee, hydrilla is often referred to as the world’s worst invasive aquatic plant. It can grow up to one inch per day, eventually forming dense surface mats thatblock sunlight and deplete oxygen.

Hayden said the possibility of hydrilla reaching Lake Waramaug remains a constant concern.

“If there is anything that keeps me up at night, it’s hydrilla,” he said.

Monitoring and
prevention efforts

Hayden said the lake conservancy already maintains a strong monitoring program. Four times a year, an aquatic plant specialist surveys the shoreline looking for invasive species. “We have been able to eradicate the invasives using mapping and hand-pulling techniques,” he said.

Additional precautions are already in place at the public boat ramp. Every boat and trailer entering the lake is inspected for plant life by monitors working under the town’s parks and recreation department.

The conservancy is also launching an education campaign and installing signs around the lake reminding boaters to clean, drain and dry their watercraft before entering the water.

“It’s not just Lake Waramaug,” Hayden said. “We are looking beyond the shoreline to see where these invasives are coming from and eradicating them.”

Despite those efforts, Hayden said the threat remains. “Hydrilla is a very formidable foe and it’s all around us,” he said. “It’s only a matter of time if we are not vigilant.”

He pointed to the infestation at East Twin Lake. “Over the last three years, they have spent more than $1 million” attempting to control hydrilla there.

Proposed
decontamination station

Officials are considering installing a boat decontamination station at the New Preston firehouse, up from the Lake Waramaug boat launch.

The program is estimated to cost about $100,000 annually, including roughly $15,000 for the decontamination trailer plus labor costs to staff the station during the boating season.

In response to one attendee’s question as to why the sanitization station is not at the state boat launch, Jim Brinton, Washington’s First Selectman, explained that locating the system away from the launch area would help prevent contaminated water from draining back into the lake while also avoiding traffic congestion.

The off-site station would also reduce staffing pressure at the launch and help avoid congestion at the boat ramp during busy times.

“We felt that our park and rec staff does not have the bandwidth to do this,” Brinton said.

Brinton acknowledged the station may not be used every day but said the preventive benefit could be significant.

“We may get no one, but at the same time we may prevent hydrilla from getting into the lake,” he said. “If anyone has a better alternative, I’d like to hear it.”

An added layer
of protection

Dean Sarjeant, a member of the Lake Waramaug Authority, said the sanitization system would provide the “next level of protection against hydrilla.”

While boat monitors have done a strong job inspecting vessels at the launch, he said visual inspections alone cannot detect every potential hiding place.

“We’ve been very lucky,” Sarjeant said, “but we don’t want to press our luck.”

Certain areas of boats and trailers — including ballast tanks and other enclosed spaces — are difficult to inspect.

“In the past we sent them away as a precaution,” he said of boats with features where visual inspection is not possible.“With the decon system, they can go to the station, get cleaned and come back to the lake. It might be a half hour or 45 minutes out of their day, but they’ll be back. We want them to enjoy the lake.”

The process would involve spraying boats and trailers with 140-degree water for several minutes to kill invasive plant fragments. “If we can’t see potential hiding places for hydrilla, we are going to decontaminate it,” he added.

“We thought the boats were safe, and they could have possibly been,” Sarjeant noted. “But now we will be 100 percent sure.”

Brian Zipp, co-chairman of the Lake Waramaug Conservancy, said boats that pass inspection receive a metal tag connecting the boat and trailer. If the tag remains intact, the boat can return to the lake without another inspection. If the tag is removed or broken, the vessel would need to be inspected again.