Frequently Asked Questions About the Floodplain Mapping Updates

Please also see WI DNR's Frequently Asked Questions about Floodplain Map Modernization.

• 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 preliminary FIRM maps show my house is in the floodplain. Should I file an appeal, protest or comment to get the maps changed?

• A: The Federal Emergency Management Agency (FEMA) will not make changes to the regional FIRM maps for one lot or one structure. FEMA has established the Letter of Map Amendment (LOMA) and Letter of Map Revision based on Fill (LOMR-F) for revisions at this scale. 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.

• Q: I already have a LOMA or a LOMR-F from FEMA. How can I tell if the proposed maps reflect this?

• A: Look in the Summary of Map Amendments (SOMA) document for your community to see if your LOMA or LOMR-F has been incorporated, not incorporated, automatically revalidated, superseded, or will need to be redetermined as a result of the mapping updates. You will need your LOMA or LOMR-F number.

• Q: Why can't FEMA simply amend the FIRM maps to leave my house out of the flood hazard area?

• A: FEMA's technical standards require that all floodplains in Dane County be comprehensively mapped to areas as they would appear during an actual flood. If the maps were to attempt to map every house that is proven to be higher than the predicted flood elevation with spot elevations on ground surrounding the structure, they would not meet those standards without having a comprehensive survey of entire neighborhoods that are mapped in the floodplain. FEMA standards require that the FIRM maps show the 'outer limit' of the area that would flood naturally throughout the floodplain. Using partial information, on a few properties within that area, would not meet FEMA standards, and more specifically would not correctly show the actual area that would flood naturally.

• Q: I've looked at the preliminary FIRM maps, and it seems there are serious cartographic errors in the proposed floodplain boundaries that affect not only my property, but my whole neighborhood. In fact, the floodplain boundaries seem to directly conflict with standard topographic information, like the Dane County 4-foot contour information available through DCI Map. Is this grounds for a protest or comment on the preliminary FIRM maps?

• A: It may be grounds for a protest or comment. However, for some portions of the floodplain mapping the County 4ft. data was not used. In those areas, 2ft. data was developed from 2005 flight data. To know which areas have been updated to the 2ft. data, check the Dane County Land Information web page. Also, for some portions of the City of Madison, mainly along Starkweather Creek, 2ft data from the City was used to make the map.

  Otherwise, all of the rest of Dane County was mapped using the County 2000 4-foot contour data, and should 'fit' within those contour lines (although you may see the flood boundary cross contour lines in some locations based on the slope of the predicted flood elevation on the land). Check the Base Flood Elevation (BFE) on the map closest to your location, or the 'flood profile' in the Preliminary Flood Insurance Study Report for that waterway. If you believe that you have more accurate data for the ground elevation adjacent to your structure, then this is exactly the kind of error that the public review process is intended to correct. As noted on our Protests and Comments page , please direct such comments to your local floodplain management agency. Obviously, the more information you can provide about such apparent errors, the easier it will be for your local government to recommend map amendments to DNR and FEMA. Some neighborhoods have worked together with a professional surveyor, engineer or landscape architect to jointly develop more accurate ground elevation survey data for several city or subdivision blocks, that would be meaningful when applied to the Preliminary Map. The amount of data needed will depend on the size of the mapped floodplain and amount of that area proposed to be revised.

Date Revised: 3/5/07 Planning & Development Home