Select Board closes hearing on AHC site plan, asks planner to draft conditions after stormwater waiver agreement

The Acton Select Board closed a public hearing on a site plan special permit application from AHC Incorporated for properties at 358A and 358B Great Road after the applicant and the town’s third‑party engineer agreed on stormwater measures and the board asked staff to draft conditions for a later vote.

The applicant sought waivers under Chapter X of the town’s land disturbance rules for a specific volume‑retention requirement. Senior Planner Kayla Sauer told the board that the applicant met with Paul Kirschner of Samske & McNary and GCG (the town’s third‑party civil engineer). GCG reviewed updated plans and “confirms can meet the maximum extent practical,” Sauer said, and recommended granting the waivers.

The application proposes two additions to an existing single‑family dwelling and rebuilding office space into a mixed‑use building with retail and three dwelling units. Paul Kirschner described a vegetative filter strip behind the garage: a grassed treatment area intended to slow runoff, encourage sediment deposition and improve water quality. He said the strip will be included in the project’s operations and maintenance (O&M) plan and inspected annually.

Board members and staff clarified the waiver scope. Paul Kirschner and Kayla Sauer said the waiver specifically relates to a Chapter X requirement that would otherwise require on‑site retention of 0.8 inches of runoff across impervious surfaces. The applicant’s design reduces impervious area and includes an infiltration trench and the vegetative filter strip; the applicant asked for the waiver for the specified retention volume while maintaining other Chapter X requirements that prevent increasing post‑development runoff off‑site.

Planning staff and GCG also asked for additional detail in the permit decision about long‑term maintenance of the vegetative strip. Kayla said Paul submitted an updated O&M plan earlier that day and that maintenance language is a standard condition for site plan approvals.

The board also discussed Design Review Board comments on the mixed‑use building’s window pattern; Kayla said the DRB chair reviewed revised architectural drawings and noted a remaining window‑pattern discrepancy on one elevation. The applicant represented by Kirschner submitted an updated architectural plan late that day, and the board asked that DRB confirm the revision as a condition.

Conservation Commission review was discussed: Kayla reported that the Conservation Commission reviewed the plan as submitted to the board but that the vegetative filter strip was not in the version they reviewed; she said she would coordinate with the conservation agent to confirm any additional filings required.

Action: With no further public testimony, Select Board member David Martin moved to close the hearing; the clerk called the roll and the motion passed unanimously. The board directed the senior planner to draft conditions that (at minimum) incorporate GCG’s recommendations, the submitted O&M plan, verification from DRB on the window revisions and any Conservation Commission follow‑up. The board will review the draft decision at a future meeting before any final vote on the permit.

Why it matters: The town must balance redevelopment and stormwater protections in riverfront‑adjacent areas. The board’s approach — requiring an O&M plan and third‑party concurrence that the design meets standards “to the maximum extent practicable” — creates enforceable conditions while allowing the project to proceed through the permitting process.

What’s next: Planning staff will prepare a draft decision with the conditions discussed and return it for the board’s review at a later meeting.