Virginia - National Flood Hazard Layer Inventory Table GIS Open Data via FEMA's National Flood Hazard Layer (NFHL) Status, and more directly Search Results Table.
The National Flood Hazard Layer (NFHL) data incorporates all Flood Insurance Rate Map (FIRM) databases published by the Federal Emergency Management Agency (FEMA), and any Letters of Map Revision (LOMRs) that have been issued against those databases since their publication date. It is updated on a monthly basis. The FIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper FIRMs.
The FIRM 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-annual-chance flood event, and areas of minimal flood risk. The FIRM Database is derived from Flood Insurance Studies (FISs), previously published 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 FEMA.
The NFHL is available as State or US Territory data sets. Each State or Territory data set consists of all FIRM Databases and corresponding LOMRs available on the publication date of the data set.
The specification for the horizontal control of FIRM Databases is consistent with those required for mapping at a scale of 1:12,000. This file is georeferenced to the Earth's surface using the Geographic Coordinate System (GCS) and North American Datum of 1983.
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 FIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The FIRM Database serves to archive the information collected during the Flood Risk Project.
Location and attributes for alluvial fan areas shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for a tiling index for raster data used for the FIRM base map.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for base flood elevations lines shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for Coastal Barrier Resource System units shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for the coastal gages for the study area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for coastal transect lines shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for points used to calculate vertical datum conversion factors.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for FIRM hardcopy map panels.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes flood insurance risk zones shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for boundaries of flood insurance risk zones shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for riverine gages used to determine discharges for the study area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for flood control structures shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for historic high water marks for the study area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for lines that represent the connectivity between the subbasins and flow direction between nodes within the study area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for leader lines for labels shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for labels shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial dataset consisting of lines that represent the centerlines of levees.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of lines that depict the limit of 18-inch or greater coastal waves in a Coastal AE Zone.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of polygons that depict effective LOMRs that have been incorporated into the NFHL since the last publication of the FIRM panel for the area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes of points that depict locations of computed discharges for the 10-, 2-, 1-, and 0.2-percent-annual-chance floods.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for the primary frontal dune features for the coastal study area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes of sections, townships and ranges shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for political jurisdictions shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of lines showing the flow path used for floodplain modeling and mapping.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for river mile markers shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of points indicating the location of the reference point that was used as the origin for distance measurements along streams and rivers.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for subbasins used in the hydrologic analysis.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of polygons depicting the extents of the studied area.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial dataset consisting of polygons depicting areas of low confidence topographic data.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for roads, railroads and other transportation features shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
A spatial data set consisting of lines that represent the 0.0-foot elevation contour used for coastal modeling and mapping.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for hydrography features shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for hydrography features shown on the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
Location and attributes for cross-section lines in the area covered by the FIRM.
FEMA FIRM Database Technical Reference (available in the FEMA Library at http://www.fema.gov/media-library/assets/documents/34519).
The NFHL is made up of several data themes containing both spatial and attribute information. These data together represent the current flood risk for the subject area as identified by FEMA. The attribute tables include SFHA locations, flood zone designations, BFEs, political entities, cross-section locations, FIRM panel information, and other data related to the NFIP.
FEMA's FIRM Database Technical Reference contains a detailed description of each attribute code and a reference to other relevant information.
The following tables may be included in this data set: L_Comm_Info, L_Comm_Revis, L_Cst_Model, L_Cst_Struct, L_Cst_Tsct_Elev, L_ManningsN, L_Meetings, L_MT2_LOMR, L_Mtg_POC, L_Pan_Revis, L_Pol_FHBM, L_Profil_Bkwtr_El, L_Profil_Label, L_Profil_Panel, L_Source_Cit, L_Summary_Discharges, L_Summary_Elevations, L_Survey_Pt, L_XS_Elev, L_XS_Struct, S_Alluvial_Fan, S_Base_Index, S_BFE, S_CBRS, S_Cst_Gage, S_Cst_Tsct_Ln, S_Datum_Conv_Pt, S_FIRM_Pan, S_Fld_Haz_Ar, S_Fld_Haz_Ln, S_Gage, S_Gen_Struct, S_HWM, S_Hydro_Reach, S_Label_Ld, S_Label_Pt, S_Levee, S_LiMWA, S_LOMR, S_Nodes, S_PFD_Ln, S_PLSS_Ar, S_Pol_Ar, S_Profil_Basln, S_Riv_Mrk, S_Stn_Start, S_Subbasins, S_Submittal_Info, S_Topo_Confidence, S_Trnsport_Ln, S_Tsct_Basln, S_Wtr_Ar, S_Wtr_Ln, S_XS, Study_Info.
Use the numbers shown below when referencing layers by number. 0. NFHL Availability
- LOMRs
- LOMAs
- FIRM Panels
- Base Index
- PLSS
- Toplogical Low Confidence Areas
- River Mile Markers
- Datum Conversion Points
- Coastal Gages
- Gages
- Nodes
- High Water Marks
- Station Start Points
- Cross-Sections
- Coastal Transects
- Base Flood Elevations
- Profile Baselines
- Transect Baselines
- Limit of Moderate Wave Action
- Water Lines
- Layer Not Used
- Political Jurisdictions
- Levees
- General Structures
- Primary Frontal Dunes
- Hydrologic Reaches
- Flood Hazard Boundaries
- Flood Hazard Zones
- Submittal Information
- Alluvial Fans
- Subbasins
- Water Areas
Source: GIS Web Services for the FEMA National Flood Hazard Layer (NFHL) - FEMA: Mapping Information Platform