Frequently Asked Questions About Floodplain Maps

  • Q: What do "Zone AE," "Zone A," and "Zone X" mean on the FIRM maps?

  • A:
    • Zone AE are areas that have a 1% probability of flooding every year (also known as the "100-year floodplain"), and where predicted flood water elevations above mean sea level have been established. Properties in Zone AE are considered to be at high risk of flooding under the National Flood Insurance Program (NFIP). Flood insurance is required for all properties in Zone AE that have federally-backed mortgages. Construction in these areas must meet local floodplain zoning ordinance requirements, including evidence that priniciple structures are above the Base Flood Elevation (BFE) as shown on the adopted FIRM maps.
    • Zone A are areas that have a 1% probability of flooding every year (also known as the "100-year floodplain"), and where predicted flood water elevations have not been established. Properties in Zone A are considered to be at high risk of flooding under the National Flood Insurance Program (NFIP). Flood insurance is required for all properties in Zone A that have federally-backed mortgages. Construction in these areas must meet local floodplain zoning ordinance requirements. New construction in Zone A areas may also require submission of engineering cross-sections of the waterway to determine Base Flood Elevations and floodway and floodfringe boundaries.
    • Shaded Zone X are areas that have a 0.2% probability of flooding every year (also known as the "500-year floodplain"). Properties in Shaded Zone X are considered to be at moderate risk of flooding under the National Flood Insurance Program. Flood insurance is not required for properties in Zone X. Local floodplain zoning ordinances do not apply to Zone X.
    • Unshaded Zone X are areas that are above the 0.2% flood elevation. Properties in unshaded Zone X are considered to be at low risk of flooding under the National Flood Insurance Program. Flood insurance is not required for properties in Zone X. Local floodplain zoning ordinances do not apply to Zone X.
    For more information on flood zones, see FEMA's FloodSmart web page.
  • Q: What are the "floodfringe" and "floodway"?

  • A:
    • The floodfringe is defined in NR 116, Wisconsin Administrative Code as: "that portion of the floodplain outside of the floodway, which is covered by flood water during the regional flood. The term, floodfringe, is generally associated with standing water rather than flowing water." Under local floodplain zoning ordinances, construction may be permitted in a floodfringe if it meets certain standards. New residences must be at least two feet above the Base Flood Elevation, they must have dry land access, and must not exacerbate flooding problems elsewhere.
    • The floodway is defined in NR 116, Wisconsin Administrative Code as: "the channel of a river or stream, and those portions of the floodplain adjoining the channel required to carry the regional flood discharge." Floodways are generally associated with moving water during a flood event. Under local floodplain zoning ordinances, most construction is prohibited in a floodway.
  • Q: Where can I find out what local floodplain zoning standards may apply to my property?

  • A: For properties in unincorporated Dane County, the entire text of the Dane County Floodplain Zoning Ordinance (Chapter 17, Dane County Code) is available on the county web page. For properties within incorporated cities and villages, check with your local government, and ask for the agency that handles floodplain zoning permits.
  • Q: I have data to show that my house is above the proposed Base Flood Elevation, but the adopted floodplain maps show my house is in the floodplain. How do I get the maps changed to reflect the engineering data?

  • A: FEMA has established the Letter of Map Amendment (LOMA) and Letter of Map Revision based on Fill (LOMR-F) for corrections to the FIRM maps. More information about the LOMA and LOMR-F processes, including appropriate forms, are available on FEMA's website.
    • Letter of Map Amendment (LOMA): Landowners or renters who wish to document that their home is naturally above the Base Flood Elevation, even though it may be shown in a flood hazard area on the FIRM map, should apply directly to FEMA for a Letter of Map Amendment.
    • Letter of Map Revision based on Fill (LOMR-F):Landowners or renters who, after obtaining appropriate permits, have brought in fill to elevate their property above the Base Flood Elevation should apply directly to FEMA for a Letter of Map Revision based on Fill.

Other Resources:

Date Revised: 5/22/09 Planning & Development