Step 5: Estimating a Conservative Base Flood Elevation at the Property

The BFEs for rivers and other non-coastal bodies of water shown on the flood map are rounded to the nearest foot. This means they are only accurate to plus or minus 6 inches. For an accurate BFE, floodplain professionals must use the riverine Flood Profiles, or Stillwater Data Tables in the Flood Insurance Study (FIS).

To roughly estimate a Base Flood Elevation (BFE) at a property, the upstream BFE lines (label) shown near the property on the flood map may be used. For example, if BFE line 110 is nearest the upstream corner of the property, you may conservatively estimate the BFE at the property as 110.5.

Use the upstream corner of house (110), then add .5 feet (since we know the 110 number on map is +/- .5 feet) = 110.5 as a conservative or rough estimate of the BFE.

Be aware that BFE’s are rounded to the nearest meter in the Commonwealth of Puerto Rico.

The base flood elevations (BFEs) lines closest to a property are highlighted on a Flood Insurance Rate Map panel. The BFE line showing 110 feet is closest to property and structure.

Note

There is a separate independent study course, IS-0274 How to Use a Flood Insurance Study that explains how to determine an accurate BFE.