A preliminary plan for an eight‑lot subdivision at 524 Salmon Falls Road drew detailed technical questions on July 7 about drainage, slope and future connectivity as the developer proposed linear bioswales and infiltration rather than a typical detention pond.

The discussion matters because the site slopes roughly 24 feet from the road to the rear of the lot, abuts school property and wetlands, and neighbors and board members said previous flooding problems in the area make drainage design critical.

Bruce Skimmon of Emmanuel Engineering and James Veron Associates presented for Copley Properties LLC and described a single access road with a cul‑de‑sac and an approach that would place bioswales and sand filters along the road to infiltrate and treat stormwater incrementally. “By doing a swale, the way we propose, there’s treatment. It comes… we’ve designed with mulch at the surface to help hold the water,” Skimmon said, explaining the design’s sand‑filter and storage‑stone layers and noting the approach reduces the need for a detention pond that can be poorly maintained.

Board members and a neighbor pressed the applicant on the steep grade and the volume of impervious surface from an asphalt road, driveways and possible sidewalks. A board member summarized the concern: “You take homes of this density… then that water is going to have very little or no opportunity to return to the ground fully. That is likely going to run off the property,” citing prior flooding issues in the area.

Planning staff told the board the technical review group (TRG) had reviewed the preliminary plan and listed department comments in a staff memo; staff also recommended that the developer consider providing a future access easement at the end of the proposed cul‑de‑sac to allow connection to a currently vacant parcel to the north and east. Staff noted a typical width for a future city street easement would be about 50 feet and suggested the board and TRG refine the exact dimension during formal review.

The developer said the proposed street would be built to city standards and that the cul‑de‑sac center is currently planned as paved, though the applicant was open to a landscaped or grass center to help with drainage. Skimmon noted fire‑truck turning diagrams were included with the plans and that stormwater storage could be incorporated in a center island if desired.

The board and staff listed items they expect at formal submittal: detailed drainage calculations, maintenance plans for the proposed bioswale and any fee‑ownership or easement language for long‑term maintenance, test pits and infiltration rates, and consideration of sidewalks given a nearby new school. No vote was taken because the application was preliminarily reviewed; staff said the TRG comments and formal checklist items would guide the next submission.

Neighbors and board members asked the developer to address stone walls on the site; the applicant said some stone walls would likely be removed for the road alignment but that preservation of other walls would be considered. The applicant also proposed a 10‑foot fee‑ownership strip to cover overflow maintenance beyond the end of the swale; staff said same will be assessed in TRG.