Conservation Commission warns MassDOT Route 9 redesign could increase downstream flooding

Matt Gardner, chair of the Conservation Commission, told the Select Board the state Department of Transportation is treating a Route 9 bridge/interchange project as an in‑kind replacement despite design changes that the commission believes will increase downstream runoff.

"MassDOT's own numbers show that this project will increase stormwater discharge by 40 cubic feet per 2nd during a significant rain event," Gardner said, describing that as "about 300 gallons per 2nd" flowing toward Camp Mary Bunker. He told the board the neighborhood drainage is at capacity and called the state's promise to "monitor" after construction "not a plan."

Gardner asked the Select Board to support the Conservation Commission’s position, work with town counsel, and involve state representatives on Beacon Hill if needed. The board requested the commission submit a written summary of its requested actions so the item can be agendized for follow‑up with appropriate staff and legal review.

The commission framed its concern as both an engineering question and a legal/process one: if a project materially increases runoff and impacts downstream properties, the commission argued, it should not qualify for local wetlands permitting or be exempted from an environmental review.