Residents press stormwater, traffic and historic‑preservation questions at Greenburgh hearing on Knowles expansion

Supervisor Paul Feiner on Wednesday opened a public hearing on Bethel Communities Management’s application to expand the Knowles continuing‑care retirement community at 55 Grasslands Road in Valhalla. The proposal seeks a zoning map amendment, an amended site plan and a special‑permit amendment to add independent living units and a ~41,000‑square‑foot building footprint, while opponents said the plan’s total square footage and impacts are larger than public notices suggested.

The hearing attracted dozens of neighbors, Knowles residents and technical consultants who traded detailed concerns and counterpoints. The applicant described revisions that moved the new building farther from nearest homes (from 66 to 78 feet), added landscaping (about 149 mature trees in the immediate buffer) and redesigned a stormwater system the team says will handle an extreme 9.1‑inch rainfall over 24 hours. The applicant also said those design changes raised its costs by roughly $650,000 and reduced annual revenue.

Why it matters: Neighbors warned the town’s existing storm‑drain infrastructure is already compromised and said reducing permeable area risks worsening repeated flooding in the Stevens/Grasslands neighborhood. Several speakers urged the board to ensure off‑site drainage and downstream impacts are studied and fixed before approving additional development. Preservation advocates and the town’s Historic & Landmarks Preservation Board pressed the town to avoid demolition of a noteworthy 19th‑century house on the site or, at a minimum, to require careful salvage and incorporation of historically significant elements.

Residents and technical witnesses debated the project’s measurements. Several citizens pointed out that planning documents and agency referrals had at times described a 41,240‑square‑foot addition (the applicant calls that the addition’s footprint) while other materials list a much larger total new floor area (roughly 149,000+ square feet). The applicant’s attorney told the board the footprint number was the relevant figure for public notice but acknowledged the differing representations in project materials and agreed to provide clarifying documentation.

Traffic and stormwater: Local residents, including people who live on Stevens Lane and nearby cooperatives, described three floods in the last year and said routine heavy rain overwhelms the system. The applicant’s engineers said the redesigned on‑site basin is sized to infiltrate design storm volumes and that, under extreme overflow, overland flow would be directed toward Grasslands Road and existing collectors. Town engineering staff and the applicant acknowledged the project cannot by itself fix regional drainage deficiencies but said the plan creates on‑site storage and incorporates conservation and landscaping measures intended to reduce peak flows.

Process and next steps: The Planning Board previously reviewed the application and submitted recommendations; some members said they were given new materials late in the process and asked the Town Board to ensure the record contains the stormwater, cut‑and‑fill, and traffic clarifications before any determination. After questions from residents and board members, the Town Board voted to adjourn the hearing to June 24 and asked that staff and the applicant provide the outstanding technical documentation and corrected public‑notice language so the record can be complete before further action.

What they said: • "None of this is a minor project modification — these are significant," Amalie Lefkowitz, attorney for Bethel, said, defending the revisions and noting the applicant had responded to planning‑board and agency comments. • "The storm drain system is worse than it's ever been," said resident Eric Lindsley, recounting repeated flooding in the neighborhood. • Madeline O’Shea, chair of the Historic & Landmarks Preservation Board, urged the board to consider alternatives to demolition, saying the house at 55 Grasslands is architecturally significant and could be incorporated into the design.

The hearing remains open and the Town Board will reconvene the matter on June 24. The board asked staff to circulate the applicant’s clarified project description, the stormwater management plan (SWIP), the cut‑and‑fill analysis and a consolidated response to Planning Board comments in advance of the reconvened hearing.