Town continues O'Sullivan wetlands hearing as applicant agrees to submit construction protocol

The Shelter Island Town Board continued the public hearing on the O'Sullivan wetlands permit for 74 Potonic Avenue after the applicant agreed to deliver a construction protocol and additional technical drawings for review.

Nick Sherman, presenting the revised plan for the property, said the project removes a roof deck and proposed pool, relocates HVAC equipment, replaces an old cesspool with an IA septic system, and adds stormwater controls designed for a 4-inch rainfall — double the town code requirement. Sherman said the project’s stormwater and septic redesigns are intended to lessen impacts on the adjacent wetlands and that he would provide a construction protocol for the excavation and foundation work “in 10 days.”

Theresa Mason, the town’s environmental consultant, told the board she supports the application’s mitigation but recommended stronger safeguards for the work that will require excavation under an existing dwelling. “Because it is more than doubling the size of the home … I am strongly recommending the 30-foot buffer,” Mason said, adding she wanted a construction protocol and structural information to ensure the house can be preserved without demolition during foundation work.

Other board members raised concerns about the depth of the proposed basement and the risk of hydrostatic pressure on the foundation. One member argued the expanded living area and new basement could be excessive for a sub-half-acre lot, a point Sherman disputed as unrelated to groundwater intrusion and said the basement work does not fall under wetlands jurisdiction but will be covered by building department review. Mason and Sherman agreed a construction protocol and review by the town engineer or building department would reduce the board’s risk of an unintended structural failure during excavation.

The board voted to continue the hearing to allow the town staff and consultants to review the promised construction protocol and related materials. The applicant committed to delivering the protocol within about 10 days to allow a timely review before the board’s next hearing date.

Why this matters: The project proposes replacing failing septic infrastructure, reducing impervious coverage within the wetland setback and adding stormwater controls — measures the board’s advisory committees said improve wetland protection. The board, however, demanded stronger documentation to protect the existing structure during excavation and encouraged a wider vegetative buffer to preserve the wetlands edge.

Next steps: The applicant will submit a construction protocol and supplemental drawings to the town for review; the board left the hearing open for those materials and for any follow-up comments from the town engineer and conservation advisor.