Engineers begin phased study of Stockbridge dam; town warned of tree removal, permits

Stockbridge officials said on Tuesday that engineering consultants have completed preliminary inspections and surveys at the town dam and will move this summer into hydrological and hydraulic studies that will determine whether repairs are needed.

"They've done the review of all existing information...they've begun the wetland delineation and they just informed me the other day that they were up the topographical survey," said Michael Canales, who presented the update to the Stockbridge Stewardship Committee. Canales said the next phase will include bore sampling and hydrological assessments that will dictate any required work.

Canales emphasized that last year's drawdown was a precaution to relieve pressure; early reviews found no evidence of seepage through the dam’s clay core. "The good news was that the clay showed no evidence of seepage," he said, while adding that the study could still identify spillway deficiencies or seepage that would require remediation.

Committee members pressed concerns about vegetation on the berm. Canales said dam‑safety rules require a maintained 10‑foot clear zone at the toe of the berm and that removing trees and stumps could be substantial work. He cited a preliminary estimate of roughly $250,000 for required tree work and said stumps would need to be backfilled and stabilized to avoid undermining the structure.

Officials stressed regulatory coordination. Canales said the project will require filing a Notice of Intent with the conservation commission, state permits and review by Natural Heritage and the Office of Dam Safety because the structure is treated as a "high‑hazard dam," a designation that influences design and funding options. Canales told the committee he expects substantive reports by late fall and early winter and will share findings at future meetings.

The committee did not take any formal repair votes at the meeting; Canales said the town has money appropriated to complete further phases of the study and will pursue state grant programs and town‑meeting matching funds if the work identified in the analyses requires construction.