Cross Sections

The FIRM is the basis for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program (NFIP). Insurance applications include enforcement of the mandatory purchase requirement of the Flood Disaster Protection Act, which "... requires the purchase of flood insurance by property owners who are being assisted by Federal programs or by Federally supervised, regulated or insured agencies or institutions in the acquisition or improvement of land facilities located or to be located in identified areas having special flood hazards," Section 2 (b) (4) of the Flood Disaster Protection Act of 1973. In addition to the identification of Special Flood Hazard Areas (SFHAs), the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered through the NFIP. This database has been created by digitizing data from georeferenced paper FIRM maps and adding information from FIS where available. All FIRMs were georeferenced at a 1:4000 scale or finer. This data should be used as a reference layer, not as an authoritative source. The hardcopy Flood Insurance Rate Map (FIRM) and the accompanying Flood Insurance Studies (FISs) are the official designation of SFHAs and Base Flood Elevations (BFEs) for the NFIP. For the purposes of the NFIP, changes to the flood risk information published by FEMA may only be performed by FEMA and through the mechanisms established in the NFIP regulations (44 CFR Parts 59-78). These digital data are produced in conjunction with the hardcopy FIRMs and generally match the hardcopy map exactly. However, the hardcopy flood maps and flood profiles are the authoritative documents for the NFIP. Section 11 of FEMA's "Flood Insurance Rate Map (FIRM) Database Technical Reference: Preparing Flood Insurance Rate Map Databases (Nov. 2022)" document contains a detailed description of each attribute code and a reference to other relevant information. https://www.fema.gov/flood-maps/guidance-reports/guidelines-standards/technical-references-flood-risk-analysis-and-mapping https://www.fema.gov/sites/default/files/documents/fema_firm-database-technical-reference_112022.pdf