Floodplain Maps and Technical Resources

Floodplain Maps

The official floodplain is typically shown through a FEMA Flood Insurance Rate Map (FIRM). This map delineates the special flood hazard areas, or flood zones. These flood zones determine how a community will regulate development in the floodplain and where flood insurance will be required when getting a federally backed mortgage.

Landowners should work with their local government to access the best available flood maps for their area. If your property is within a city, contact the city. For property owners outside of city boundaries, contact the county.

Available Maps

  • FEMA's National Flood Hazard Layer Viewer - View Digital Flood Insurance Rate Maps (DFIRMs) for modernized counties updated since 2003.
    • Digital Flood Insurance Rate Maps (tutorial PDF)
  • FEMA Map Service Center - View Digital Flood Insurance Rate Maps (DFIRMs) for modernized counties and paper maps for unmodernized counties, as well as Flood Insurance Studies.
    • Paper Maps and Flood Insurance Studies (tutorial PDF)
  • Minnesota Geospatial Commons - For GIS users. Dataset contains effective floodplain data for all mapped flood areas. Estimated 1% Water Surface Elevations layer is available and provides model-based elevations for many effective A-Zones or areas that are not yet mapped.
  • DNR Floodplain Program FTP Site - Contains preliminary and effective floodplain data for all counties that have had map updates since 2003.
    • PDF and GIS Floodplain Data (tutorial PDF)
Counties in yellow may access flood data from the Map Service Center. Counties in red may access flood information through both FEMA's Map Service Center and the National Flood Hazard Layer.

FEMA Map Updates

Congress has authorized $1 billion ($200 million for five years) to convert the FEMA Flood Insurance Rate Maps (FIRMs) to county-wide, digital based maps.

Map Appeals and Amendments

FEMA has established administrative procedures for changing effective FIRMs based on new or revised scientific or technical data.

Base Flood Elevations

Base flood elevations are also known as the 1% annual chance flood elevation or 100-year flood elevation. These elevations can be determined in different ways depending on the source of the floodplain map and zone of the site.

Hydraulic Models

To view and download stream segment model information, visit the FEMA Hydraulic Model.

Resources for Floodplain Development

Technical information and forms often used by engineers, surveyors and floodplain managers.