Redevelopment plan at 165 Pusatonic Street would cut and regrade site, add floodplain storage and 8,500 sq ft of riverbank plantings

At a lengthy July 15 hearing the project engineer (presenter) described a redevelopment proposal at 165 Pusatonic Street that would remove structures located very near the brook, regrade portions of the site to provide compensatory floodplain storage and construct a new building set farther from the stream.

Presenter (speaker 9) said the plan interprets the FEMA-regulatory floodplain elevation (880.4) on a current topographic survey and proposes to lower much of the eastern half of the parcel. "Were not touching anything within the stream," the presenter said, and added the scheme increases available flood storage by about 158 cubic yards by enlarging a detention basin and lowering areas that are currently elevated.

The plan also calls for stormwater controls: underground storage chambers (presenter said roughly ten 24-inch chambers), a hydrodynamic separator to reduce suspended solids, and a multistage outlet with a 12-inch low-flow discharge sized to reduce peak flows during a 100-year storm event. The presenter said grading would place the new building roughly 60 feet further from the brook than existing structures and that the redevelopment would reduce impervious area within the inner 100-foot riverfront zone by approximately 50 square feet while increasing overall impervious area in the broader riverfront area by roughly 4,100 square feet; the increase near the pool area would be mitigated by 8,500 square feet of native plantings for filtration, shade and habitat.

Several commissioners and residents pressed for additional detail. An abutter, Marilyn White (speaker 12), asked whether the project would actually improve downstream flooding for neighbors; the presenter replied the site work improves local conveyance but does not remedy upstream culvert issues. The presenter said the surveying interprets FEMAs elevation on current ground data and that the plan intends to improve conditions adjacent to the stream by removing buildings and adding riparian plantings.

Commissioners asked for more detailed cut/fill tables, confirmation of chamber counts and elevations, and clearer breakdowns of impervious-area changes across regulatory zones. After discussion the commission voted to continue the Notice of Intent to its August 5 meeting to allow staff and the applicant to provide the requested clarifications.

Key technical figures stated at the meeting: ~158 cubic yards of additional floodplain storage; ~8,500 sq ft of proposed native riverbank plantings; ~4,100 sq ft net increase in degraded impervious area within the riverfront redevelopment area (with a net reduction of ~50 sq ft in the inner 100-foot resource area); underground storage chambers described as 24-inch corrugated chambers in repeated runs and multiple detention structures sized for the 100-year storm.

Next steps: applicant to provide additional cut/fill tables, confirmation of underground storage details and a clearer breakdown of impervious-area impacts; the commission will review material on August 5.