Tonawanda, NY Environmental Rules: Flood Elevation Requirements (2026)

Town Code § 92-5, Construction standards, sets the actual flood-elevation numbers that a floodplain development permit must meet. Section 92-5C(1)(a) requires new construction and substantial improvements to residential structures in Zones A1-A30, AE and AH, where FEMA base flood elevation data exist, to have the top of the lowest floor, including any basement, elevated to or above two feet above the base flood elevation; in Zone AH, the standard also requires drainage paths that guide floodwater around and away from the structure on sloped sites.

Where no base flood elevation data are available in Zone A, § 92-5C(1)(b) requires the applicant's registered design professional to obtain federal, state or other elevation data, or independently determine the base flood elevation using accepted hydrologic and hydraulic practice, and add two feet of freeboard either way. In Zone AO, § 92-5C(1)(c) sets the lowest floor at the FIRM-listed depth number above the highest adjacent grade plus one foot of freeboard, or two feet if no depth number is shown. Coastal Zones V1-V30, VE and V carry their own two-foot freeboard rule under § 92-5C.1(1), measured to the bottom of the lowest horizontal structural member rather than the floor itself, reflecting the added wave-action risk along the Niagara River's coastal high-hazard areas.