City of Evansville: LOMR discussed and BFE

LOMR. A Letter Of Map Revision is applied for through the City of Evansville (likely with Wisconsin DNR agreement) to FEMA. It is used to change flood zones, floodplain and floodway delineations, flood elevations, and planimetric features. A local example is a pending application which would alter the floodplain boundaries in the vicinity of Westfield Meadows and would establish BFE along the drainage ditch.

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What is the Base Flood Elevation (BFE)?

The Base Flood Elevation (BFE) is the highest water surface elevation with a 1% chance of being equaled or exceeded in a given year. The 1% flood is also know as the 100 year flood, but we all know that they can occur more frequently than every 100 years.

The BFE is used in permitting and regulation of construction in the floodplain. In general, new habitable construction must be at least 2 feet above the BFE to ensure reasonable protection of the property.

The BFE, or more correctly a building's lowest floor elevation in relation to the BFE, is a major factor in determining flood insurance premiums.

Some mapped floodplains may be designated as Zone AE. These floodplains have BFEs associated with them, which are marked on the FIRM. A Flood Insurance Study (FIS) that accompanies the FIRM will provide more detailed BFE information than the map.

Some mapped floodplains may be designated as Zone A. These floodplains have been identified as prone to flooding but have not had a formal study to establish their BFEs. Without an established BFE, there may be other documents or data that may be used in estimating the BFE for permitting and regulatory purposes.

Everything else being equal, flood insurance premiums will be greater in a Zone A than a Zone AE simply because the BFE is unknown.