Digital Flood Insurance Rate Map Database

The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk
information and supporting data used to develop the risk data. The primary risk
classifications used are the 1-percent-annual-chance flood event, the
0.2-percent-annualchance flood event, and areas of minimal flood risk. The
DFIRM Database is derived from Flood Insurance Studies (FISs), previously
published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in
support of the FISs and FIRMs, and new mapping data, where available. The FISs
and FIRMs are published by the Federal Emergency Management Agency (FEMA). The
file is georeferenced to earth's surface using the UTM projection and
coordinate system. The specifications for the horizontal control of DFIRM data
files are consistent with those required for mapping at a scale of 1:12,000.

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.
The DFIRM Database presents the flood risk information depicted on the FIRM in
a digital format suitable for use in electronic mapping applications. The DFIRM
database is a subset of the Digital FIS database that serves to archive the
information collected during the FIS.