The Conservation Commission on Tuesday expressed frustration about lawn mowing past the permanent immovable barriers on lots that are part of the Chamberlain-Whalen subdivision.

Permanent immovable barriers (PIBs) are placed to demarcate a buffer zone to ensure that the land is not disturbed. But during a review of three lots seeking certificates of compliance (COCs), members pointed out that mowing occurred beyond their respective boundary lines in two instances.

Matt Ashley, a senior project engineer at Bohler Engineering, represented Toll Brothers, the applicant. During the review of 53 Chamberlain Street, he noted that the commission previously requested to “see more growth out behind the property” before granting a COC. He said mowing on the property ceased, except for at the corner of an abutting lot, going past a PIB. These lots share a common driveway.

Ashley said he suspected that the landscaper for the abutting lot “continues to be mowing behind the PIBs throughout the entire property.” He told the commission that he would talk to the owner of that property.

“Just generally, I get very, very nervous about these properties,” said co-vice chair Ted Barker-Hook. “We’ve had struggles with them since before people moved in with the way they were being built.”

Barker-Hook lamented that the commission recently granted a COC for a lot in that subdivision. He explained that the landscaper “has now begun mowing past the PIB again.”

Also, he speculated that the mowing may stop long enough for the commission to grant its approval, but then resume shortly afterward. This is a pattern he sought to discourage.

Conservation administrator Judy Day said she recently walked the Chamberlain side of the subdivision with the landscaper hired by the homeowners association.

“I very clearly pointed out where to mow and where not to mow within at least the common areas that have PIBs near them,” she explained.

Day pointed out that, in this case, it did not seem to be the homeowner’s fault because the landscaper appeared to be trying to avoid a culvert.

Chair Melissa Recos said, in that instance, she would be in favor removing that PIB “in the field and on the plan.” With that in mind, the commission voted 4-0 to issue the COC.

For the lot at 29 Whalen Road, Ashley said that mowing was an issue there as well. While he said the tree line is being “respected,” he described the same situation as with the previous property concerning a neighbor’s landscaper being overzealous with mowing.

Said Barker-Hook: “I think it’s another problem we see again and again.”

After discussion, Ashley said he would go back to the applicant rather than seek a vote.

The COC for 28 Whalen Road was approved 4-0, as Day confirmed there were no mowing violations. But wetlands consultant Joe Orzel pointed out that there had been yard waste dumped in the buffer zone at that property. Day said she did not see it when she surveyed the property.

“But if we start to see that happening now that everybody’s aware — the HOA landscaper and the residents — then the commission is fully within their rights to issue violations,” added Day. “And I’m happy to facilitate that.”

Mowing violations would amount to $300 per day for each occurrence, explained Recos.

Barker-Hook said he would rather have split-rail fences than PIBs if new developments are proposed. Other members agreed.

Cordaville Pond Dam planting plan OK’d

The commission approved the planting plan for the Cordaville Pond Dam site in a 4-0 vote.

The dam, located near Hopkinton State Park off Cedar Street, borders Southborough. It is located on property owned by the MBTA along the Framingham/Worcester Commuter Rail line. The MBTA and the Massachusetts Department of Transportation are working on a multimillion-dollar infrastructure project to either rehabilitate or decommission the dam to maintain the safety of the track.

This project last came before the commission in October 2023. The commission approved a request for sedimentation sampling and vegetation removal at the dam, with work primarily taking place on the Southborough side.

Day told members that the order of conditions also “included a funky condition.” It required mature trees to be replaced at a 1:1 ratio at the top of the dam.

Jeremy Fontaine, an environmental construction manager with the MBTA, introduced Mike Egan, a project manager at CDM Smith. CDM Smith, a Boston-based engineering and consulting firm, is taking over the project, Fontaine explained.

Egan said there had been an assessment performed on the earthen dam. It included a hydraulic spillway capacity study, notation of structural issues and seepage concerns, an analysis of vegetation growth and a public safety review.

The assessment recommended removing vegetation, armoring the earthen embankment, lowering the spillover array, raising the earthen embankment and performing a “full dam decommissioning.” The MBTA is reviewing these five options, Egan said.

As part of the previously approved sedimentation sampling, vegetation removal was completed in November 2024.

CDM colleague Magdalina Lofstedt presented the vegetation replacement plan. She noted that the planting will be on the Southborough side of the dam because the MBTA does not own land in Hopkinton. She worked with Melissa Danza, Southborough’s conservation agent and floodplain administrator, in developing the plan because the site is too compact to replace all 49 of the removed trees.

Lofstedt proposed planting 30 trees and 19 shrubs, all of which are native species to Middlesex County. While she said Danza “blessed” this plan, it has yet to be reviewed by the Southborough Conservation Commission.

“I don’t have any issues with subbing out the 19 shrubs and 30 trees given the area limitations,” said Recos.

Barker-Hook noted that the plan indicated the tree measurements in gallons. Typically, tree replacement is assessed by the tree caliper or sapling height. He questioned how to determine their size.

Lofstedt said the trees are “pretty small,” ranging from 1-3 feet. Recos questioned if that was in height rather than diameter, which Lofstedt confirmed.

Recos pointed out that the plan described trees between 10-25 gallons, which she called a “big range in size.” Day found an illustration showing the height of trees planted in various gallon buckets. A tree in a 15-gallon bucket would equate to about 6 1/2 feet in height, Day said.

Fontaine said he would provide pictures of the trees prior to their planting once a nursery is identified. Recos and Day said that was a feasible option. Fontaine hoped planting could commence in the fall.

Hearings continued

The hearing for the proposed dam repair at Frankland Road was continued until Aug. 11. Hearings on 12 North Mill Street and proposed changes to the town’s wetlands regulations were continued until Aug. 25.