Meetings

Community meeting summary

10/29/2026 · Portland Library

Prepared from the Working Group’s official meeting notes (PDF), lightly edited for spelling and clarity. The 2027 plan details at the end come from the meeting slides.

Introductions. Rick Benson introduced the attending members of the Friends of Great Hill Pond Working Group and two guests: Russ Melmed from the Chatham Health District, and Greg Bugbee from the Connecticut Agricultural Experiment Station’s Office of Invasive Aquatic Species.

The algae bloom

Rick opened by acknowledging that the pond experienced a significant bloom of cyanobacteria during August and September. Some areas of the pond were more heavily affected than others. He then reintroduced Russ, who has many years of experience dealing with cyanobacteria blooms from a public health perspective.

Russ pointed out that cyanobacteria are native organisms, and that blooms typically occur when the nutrients available in the water get out of balance with the plants that use them. He described many factors that can contribute to a bloom, including runoff from fertilized lawns and from natural woodlands after heavy rains, droppings from geese and other animals, hot weather, and die-back of water plants. He noted that blooms had occurred in several lakes in our area, including Lake Pocotopaug and, for the first time he could remember, Lake Terramuggus in Marlborough.

Russ then explained why the Health District and other state agencies no longer use spot tests to determine the relative health risk of a bloom. Cyanobacteria move, sometimes up or down in the water column or along the water surface, with wind and other weather conditions. A visual examination is used instead. Scum on the surface should be avoided, as should bright green water, and personal judgment should be used when the water is very cloudy. Russ showed slides of the Lake Pocotopaug bloom to illustrate his point, brought some of the tools he uses for visual examinations, and gave a short demonstration.

His segment ended with a lively question and answer period covering specific health risks, whether cyanobacteria die after a bloom (they do), and other topics.

Treatment plan for 2027

Rick explained the plan, which is fairly straightforward, and also described some alternative approaches the group considered and why they were set aside.

Curly Leaf Pondweed

• One option was not to treat Curly Leaf Pondweed at all. Despite spring treatments in 2024 and 2025, it germinated from its turions (seeds) in late 2025, and by spring 2026 it had grown considerably before being treated.
• Left untreated, it would have grown to the point of again rendering portions of the pond unusable, and would have allowed the weed to produce new seeds, erasing the progress made in three years toward reducing the seed bed.
• Very few unintended effects have been attributed directly to the Curly Leaf treatments: no algae blooms, perhaps some short-term cloudiness and a little foam, and clear conditions for peak swim season.
• For these reasons the group believes it is critical to continue treating Curly Leaf Pondweed. Before treating, however, an updated survey is essential to determine exactly where it still grows. The group will ask CAES to do the survey in early spring.

Fanwort

• The group also discussed not treating Fanwort, as was the case in 2025. In 2025 it came back strong and made large portions of the northern and northeastern parts of the pond unusable. In 2026, in the deliberately untreated conservation zones, it was thick and matted.
• Where Fanwort was treated, the limnologist saw little or no growth.
• Unless the northern half of the pond is treated, it will become swamp-like and the Fanwort will spread south.
• The group considered treating earlier in the summer, when growth is less. This could reduce the decaying plant material, and with it the nutrients that might feed algae. The idea was set aside because it risked affecting more of the summer season.

The group settled on treating after Labor Day, when the water is cooler and less conducive to algae, and when a bloom, if there were one, would not occur until mid to late September.

A question was raised about how long the weeds will need to be treated. Rick asked Greg Bugbee to offer his insights. Greg explained that Curly Leaf Pondweed grows each year from turions (seeds) deposited by prior infestations. By killing the current year’s growth before it produces more turions, the amount of turions in the seed bed is steadily reduced. This can take up to 5 years, after which much smaller spot treatments may be necessary. Fanwort grows from its roots and spreading tubers, and also spreads by fragmentation. CAES has tested fall Fanwort treatments at Bashan Lake in East Haddam, with relatively successful results, but Greg cautioned that each lake is different, so direct comparisons are difficult. Continued treatments will eventually reduce the weed’s root system, but how long that will take is very difficult to predict.

Water quality testing

Frank Galicia explained that testing and recording nutrient levels and other attributes of the water at various points in the season, and after certain events, will help inform decision making. Tests will be conducted by members of the Working Group, by the Chatham Health District, and by an independent lab.

Communications

With the meeting’s time nearly up, Dave Modzelewski explained that he and others from the Working Group are updating our communication systems to better align our email lists, Facebook and website, and to allow for more community feedback.

The 2027 plan at a glance

From the meeting slides

Long-term strategy: eradicate Curly Leaf Pondweed, and manage and contain Fanwort. Timing is as stated in the Working Group’s 2027 plans, and the ranges are approximate. No algaecide treatment is planned in the event of a bloom.

• Late March to early April 2027: CAES survey to locate Curly Leaf Pondweed that grew over the winter.
• Late April to early May 2027: Curly Leaf Pondweed treatment with diquat, targeted using the CAES survey.
• Just after Labor Day (9/6/2027): Fanwort treatment with flumioxazin, based on a limnologist survey, with two coves left untreated.

2027 water testing

• April: baseline test by volunteers, before the Curly Leaf Pondweed treatment.
• May, about 2 weeks after treatment: independent lab test after the Curly Leaf Pondweed treatment.
• Late July to early August: general health test by the Chatham Health District.
• Mid-September: volunteer test after the Fanwort treatment.

Each test covers clarity, temperature, phosphorus, nitrogen, pH, E. coli and coliform. Cyanobacteria are not tested for; if a bloom occurs, the Chatham Health District advisory protocol applies.

View the meeting slides (PDF) →
Photos of the Lake Pocotopaug bloom in the slides are courtesy of the Chatham Health District.