The Needham Select Board on Sept. 24 heard a public hearing and extensive technical discussion on a proposed replacement to the town's stormwater bylaw that would raise construction permitting standards and require new on-site stormwater controls for future projects.

The working-group chair, Kevin Keane, told the board the measure would replace the town’s existing ordinance and focus on modern construction permitting standards rather than drainage-only rules. "Going up to 1 and a half inches allows us to capture 99%," Keane said, describing a change from the town's existing one-inch capture requirement to 1.5 inches over the impervious surface area.

The proposal would expand triggers for review, require soil testing and engineer certification, require post-construction operation and maintenance plans to be recorded, and require minimum volumetric capacity for new stormwater control measures. Keane said those post-construction controls would require as-built drawings and registry entries tied to the property deed. The working group also recommended that the select board adopt implementing regulations that spell out technical calculation details.

Residents and engineers pressed for clarifications during public comment. Dave Hara, a resident and professional civil engineer, urged the committee to make the requirement explicit that the required storage be a static volumetric capacity equivalent to 1.5 inches over the impervious area, not a vague infiltration performance target. "I'm just suggesting that you modify the language to make it clear that you're looking for a volume of the chamber to hold the 1.5 inches over the impervious area," Hara said.

Other residents described recurring flooding that they said followed nearby construction and asked how the bylaw would help. The working group and board members repeatedly cautioned that the bylaw is not retroactive and will not prevent every flood event tied to extreme storms such as the Aug. 8 high-intensity rainfall: the proposal applies to new construction and to projects subject to permitting going forward.

Board members and the committee discussed a tree requirement included in the draft bylaw. The draft requires planting (or in later clarifications, retention or planting as defined in regulations) of trees tied to required infiltration chambers; the select board asked that specifics (numbers, minimum caliper, native species) be moved into the implementing regulations so the bylaw can state the policy intent while technical details are handled in rules the town can update more quickly.

After the hearing and committee discussion, the Select Board voted to recommend the stormwater bylaw for the October special town meeting and asked town counsel and staff to finalize regulatory language to match the board’s intent.

The board and members of the working group said the bylaw is intended to improve resilience and raise permitting standards for new construction, but they emphasized limitations: existing finished basements and prior permits are not automatically changed by the new rule and the bylaw will not guarantee that no property will ever flood in a major storm.

The board’s recommendation means the bylaw will appear on the warrant for the Oct. special town meeting; the implementing regulations will continue to be developed and will return to the board for later approval should the bylaw pass.