Developers could soon be required to take additional steps to limit the impacts of coastal storms and rising sea levels following the Boston Planning & Development Agency’s vote last week to advance the city’s Coastal Flood Resilience Zoning Overlay District. 

Going beyond areas identified in FEMA flood maps, the zoning overlay district will make all development projects subject to BPDA’s Article 80 Large and Small Project Review to undergo Resilience Review and comply with the Coastal Flood Resilience Design Guidelines. The overlay district will apply to all areas of Boston which “could be inundated during a major coastal storm event, known as a 1 percent chance flood event with 40-inches of sea level rise,” according to a press release.

The zoning overlay will provide consistent standards for project review as well as providing new definitions and standards for building dimensions and uses. The specific provisions include elevating occupiable building space to prevent flood damage, flood proofing areas beneath flood elevations, and preventing uses including living space below flood elevation.   

The implementation of the zoning overlay is one of the primary goals of the city’s 2016 Climate Ready Boston plan. In 2019, the agency developed and adopted Coastal Flood Risk Design Guidelines for new construction and building retrofits, as well as recommendations for a Flood Resiliency Zoning Overlay District. 

The agency says based on climate modeling, Boston is expected to see 40 inches of sea-level rise around 2070, “within the usable life of most buildings currently undergoing BPDA review.

The zoning overlay will now go to the Boston Zoning Commission for approval before it goes into effect.