Falmouth conservation meeting reviews new FEMA maps, state rules that will raise coastal building standards

Shannon Holst, a floodplain specialist with Barnstable County’s Cape Cod Cooperative Extension and WHOI Sea Grant, told the Falmouth Conservation Commission on Jan. 16 that changes to flood mapping and building codes will expand areas where the most stringent coastal construction standards apply. “Flood insurance rate maps, that’s what, the flood maps from FEMA are officially called,” Holst said, and added that “they do not incorporate sea level rise, or any changes in storms that we’re seeing.”

Holst said FEMA’s maps delineate the regulatory floodplain (the 1% annual‑chance area) but are “backwards looking,” and that state mapping and modeling that do include sea‑level rise are not yet regulatory. She said a new delineation—commonly called the limit of moderate wave action (LMWA) or “coastal A” zone—was added to some maps in 2017 and refined in 2021; where that coastal A zone exists, the state’s updated building code and proposed DEP (Massachusetts Department of Environmental Protection) performance standards would require V‑zone construction methods (open pilings, elevated utilities, no structural fill and restricted enclosures).

Why it matters: Holst and staff warned that the combination of the coastal A designation and a July 1 change in the Massachusetts State Building Code will mean more properties in Falmouth must be elevated on pilings, raise utilities above the mapped base flood elevation, and meet increased freeboard requirements. Holst said the building code raises freeboard…