Somerville planning board debates requiring groundwater recharge, rejects broad minor-development mandate

The Somerville Planning Board spent the bulk of its Dec. 10 meeting debating proposed stormwater ordinance changes, including a recommendation to require groundwater recharge for major developments and a new minor-development category that would regulate projects over 400 square feet.

Planner Mike summarized the draft and said one proposal would require groundwater recharge for the water-quality storm for projects that meet the borough's major-development definition. "Technically, can the borough require it? Yes," he said, but he warned of practical hurdles in Somerville's compact lots and tight soils. He noted, "You have tight soils, silts and clays" and that groundwater mounding could cause wet basements and require costly modeling and borings.

Several board members pushed back on making recharge mandatory. "If there's a reason we're exempt, I don't think we should change that," said one member, arguing the borough's status as a regional center and local soil and lot constraints make a mandate impractical. Members described the testing and design as expensive and uncertain: "You do the work, you're not locked in that it's gonna work," the planner said, noting applicants could spend money on borings and modeling with no guarantee of success.

The board also questioned a proposed minor-development category that would regulate any change over 400 square feet. Members warned it could force homeowners to hire engineers and lawyers, impose deed restrictions, and add recurring fees. "Your $10,000 deck just turned into ... another $10, 15, maybe 20 [thousand]," one member said, summarizing cost estimates for testing and professional services.

Several members suggested alternatives focused on education and incentives. One member praised the environmental commission: "Their skills at education and community engagement will have far greater of an impact than any ordinance will." Another recommended removing most of the minor-development language and returning a cleaner markup: the planner said he would "clean this up" and highlight changes in red for the next meeting.

The board did not adopt any ordinance changes at the meeting; the planner said he would prepare a revised draft that removes or narrows the contested minor-development provisions and clarifies where recharge requirements would, or would not, apply.