When there is a preliminary study with a lower BFE, which data should be used until finalized?

In scenarios involving a preliminary study that presents a lower Base Flood Elevation (BFE), it is crucial to rely on the most authoritative and finalized data until a study is accepted and adopted. Existing Flood Insurance Study (FIS) data, which has been fully vetted and approved by FEMA, provides a reliable baseline. Using the existing FIS data ensures that floodplain management decisions are based on established guidelines, which are critical for maintaining compliance with the National Flood Insurance Program (NFIP).

When preliminary findings are released, they represent a draft version and can be subject to changes based on further review, public comments, or other factors before they receive final approval. Therefore, employing the existing data assures that floodplain management practices remain consistent and compliant with current regulations.

The other data points, including preliminary studies and recommendations from local engineers, while potentially valuable, may lack the necessary rigor and finality required for compliance until they are formally accepted. This approach ensures that communities maintain effective floodplain management while waiting for final determinations.