The Conservation Commission on Tuesday night received an annual update from the town’s Department of Public Works director about this year’s weed management plan for Lake Maspenock.

Kerry Reed told the commission that this year will not include herbicide treatment. Prompted by extensive aquatic weed growth, the DPW last June applied diquat and endothall to 64.5 acres of the lake’s north basin from Sandy Beach to West Main Street. While this decision was applauded by some lake residents, others slammed the use of herbicides as a threat to the lake’s ecosystem.

The Citizens Input Group (CIG) has been studying the lake over the past decade, making recommendations about how to control both native and invasive weed species. They include fanwort, large leaf and curly-leaf pondweed and variable milfoil. Curly-leaf pondweed, Reed said, was newly observed this year.

Said Reed: “I feel like this last year really showed the success of the annual surveys and being able to kind of react to that.”

Regular drawdowns of the lake will continue, with an extended drawdown planned for next year. Extended drawdowns are preformed every three years.

CIG chair Joe Baldiga explained that “while there was a lot of angst and agony” about the herbicide application, “the effect was nothing short of remarkable.”

Boaters and swimmers were able to use the lake in August last year, which he said was virtually impossible in previous years due to dense weed overgrowth. Swans and geese also returned to the area.

“We’re not back here advocating for another weed treatment this spring,” stressed Baldiga. “We’re trying to be very judicious in what tools we use in the toolbox.”

He was hopeful that the treatment, combined with the cold winter, will have a “lasting effect” in managing weed growth. The CIG will do a spring survey.

Chair Melissa Recos thanked Baldiga for his report. She stressed that the CIG and the Lake Maspenock Preservation Association (LMPA) should continue its resident education efforts, as some homeowners need to respect the buffers around the lake.

Said Baldiga: “It is a team effort.”

Carol Esler, a member of the Sustainable Green Committee and 40-year lakefront resident, said not all residents were thrilled with the herbicide application or its results. Some waterfowl have returned to the lake, but slowly.

She also said she observed a science project done by a Hopkinton High School student at a science fair. It showed that microscopic organisms decreased after the herbicide application. Recos and Baldiga each requested further information about the project.

Reed also told the commission that repairs were made to the lower east side to the dam during the drawdown. The concrete work on the dam and levy system was completed in February. Final paving of the top is expected to be done in April. Restoration of the disturbed area downstream will commence in the spring.

The dirt access road made for construction vehicles will remain in place, Reed added.

Newbury Glen makes stormwater management improvements

Conservation Administrator Judy Day gave an update on the improvements made to stormwater management measures taken at the Newbury Glenn subdivision since the developer, Toll Brothers, was scolded at the last meeting for a series of violations.

She noted the water she observed after the previous week’s rainstorm was “pretty clean.” Seed, straw and tackifier were applied to the highly exposed areas of the site.

One problem she described was that the off-site basins appear to be leaking and producing a whistling sound. While some silty water was seen, it was far less than in previous instances, and it did not flow to Ash Street.

“I think the main issue is the basins are still filthy,” she said. “And we have more rain coming in the forecast.”

Project consultant Rich Kirby from LEC explained that an outlet control structure was installed at the off-site basins to help with runoff issues. A silt fence and compost sock were installed at the site as well as straw waddles and flock logs on the embankment of the offsite basin. A stormwater treatment swale also was added at the basins.

Street sweeping has been increased to three times per week, he added, with an emphasis on sweeping before anticipated rain.

“I think we’ve made really good progress,” said Kirby. “I think we’ve figured the site out.”

Recos said she was “pretty comfortable” with the efforts made. She mentioned the possibility of releasing permits for lots for development. After discussion, the commission decided to wait until a backup pump is installed.

Member Ed Harrow mentioned that he received several inquiries about why the commission did not levy fines against Toll Brothers. Recos responded that cease-and-desist orders are more effective, particularly with larger developers.

Added Recos: “They do have plenty of money to pay fines, but they don’t have time to wait.”

Guardrail project at Hopkinton State Park approved

A guardrail replacement plan at Hopkinton State Park proposed by the state’s Department of Conservation and Recreation received board approval in a 4-0 vote. This will improve safety because the guardrails are “pretty old,” explained representative Douglas Partridge. Work on the Hopkinton side of the project will be performed at the contract station in the northern area of the park.