Floodplain Management

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.

Access Flood Maps

  • FEMA Map Service Center This link leads to an external site.- 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)
  • FEMA's National Flood Hazard Layer Viewer This link leads to an external site.- View Digital Flood Insurance Rate Maps (DFIRMs) for modernized counties updated since 2003.
    • Digital Flood Insurance Rate Maps (tutorial PDF)
  • Minnesota Geospatial Commons This link leads to an external site.- 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 This link leads to an external 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

Information on the map update process and timelines for updating map data.

Map Appeals and Amendments

FEMA has established administrative procedures for changing or challenging effective FIRMs based on new or revised 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 Model

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

Technical Resources for Floodplain Development

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