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Data format: Shapefile File or table name: Lee_fld_haz_ar Coordinate system: Transverse Mercator Theme keywords: FEMA Flood Hazard Zone, DFIRM, Digital Flood Insurance Rate Map, Special Flood Hazard Area, DFIRM Database, NFIP, SFHA, Flood Insurance Rate Map, FIRM, Riverine flooding, Floodway, Base Flood Elevation, Coastal flooding, Coastal Barrier Resources System Areas |
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Abstract:
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-annual-chance 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 State Plane 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 effective date of the published FEMA maps is August 28, 2008.
** The following work was subsequently performed (May 13, 2008) by Lee County GIS Department on receipt of
the preliminary DFIRM. The flood polygons were intersected with the BFE lines to create discrete polygons,
to which the BFE was assigned. A new field FLOODZONE was added and populated with a concatenation of
FLD_ZONE and BFE. The resulting dataset is Lee_fld_haz_ar. **
Letters of Map Change (LOMC) and Letters of Map Revision within unincorporated Lee County have been
incorporated into FIRM_yearmoda.shp by Lee County GIS. Last updated on 20170401. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
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-annual-chance 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 State Plane 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 following work was subsequently performed (May 13, 2008)on the preliminary DFIRM by Lee County GIS Department. The flood polygons were intersected with the BFE lines to create discrete polygons, to which the BFE was assigned. A new field FLOODZONE was added and populated with a concatenation of FLD_ZONE and BFE. The resulting dataset is Lee_fld_haz_ar. ** Letters of Map Change (LOMC) and Letters of Map Revision within unincorporated Lee County have been incorporated into FIRM_yearmoda.shp. Last updated on 20170401.
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.
FIRM and FIS effective date
The hardcopy FIRM and DFIRM and the accompanying 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 matches the hardcopy map exactly. However the hardcopy flood maps and flood profiles are the authoritative documents for the NFIP. Acknowledgement of FEMA would be appreciated in products derived from these data.
500 C Street, S.W.
The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hard copy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the SFHAs. As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. Attribute accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed. To obtain more detailed information in areas where Base Flood Elevations (BFEs) and/or floodways have been determined, users are encouraged to consult the Flood Profiles and Floodway Data and/or Summary of Stillwater Elevations tables contained within the FIS report that accompanies this DFIRM database. Users should be aware that BFEs shown in the S_BFE table represent rounded whole-foot elevations. These BFEs are intended for flood insurance rating purposes only and should not be used as the sole source of flood elevation information. Accordingly, flood elevation data presented in the FIS report must be used in conjunction with the FIRM for purposes of construction and/or floodplain management. The 1-percent-annual- chance water-surface elevations shown in the S_XS table match the regulatory elevations shown in the FIS report.
When FEMA revises an FIS, adjacent studies are checked to ensure agreement between flood elevations at the boundaries. Likewise flood elevations at the confluence of streams studied independently are checked to ensure agreement at the confluence. The FIRM and the FIS are developed together and care is taken to ensure that the elevations and other features shown on the flood profiles in the FIS agree with the information shown on the FIRM. However, the elevations as shown on the FIRM are rounded whole-foot elevations. They must be shown so that a profile recreated from the elevations on the FIRM will match the FIS profiles within one half of one foot.
Data contained in the DFIRM Database files reflect the content of the source materials. Features may have been eliminated or generalized on the source graphic, due to scale and legibility constraints. With new mapping, FEMA plans to maintain full detail in the spatial data it produces. However, older information is often transferred from existing maps where some generalization has taken place. Flood risk data are developed for communities participating in the NFIP for use in insurance rating and for floodplain management. Flood hazard areas are determined using statistical analyses of records of river flow, storm tides, and rainfall; information obtained through consultation with the communities; floodplain topographic surveys; and hydrological and hydraulic analysis. Both detailed and approximate analyses are employed. Generally, detailed analyses are used to generate flood risk data only for developed or developing areas of communities. For areas where little or no development is expected to occur, FEMA uses approximate analyses to generate flood risk data. Typically, only drainage areas that are greater than one square mile are studied.
The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM are issued as the official designation of the SFHAs. As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. Horizontal accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed.
The DFIRM Database consists of countywide vector files and associated attributes produced in conjunction with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the SFHAs. As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. Vertical accuracy was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing of FEMA's DFIRM database was also performed.
Spatial and attribute information for cross sections, floodplain information, BFEs, general structures, and station start descriptions.
Spatial and attribute information for cross sections, BFEs, station start descriptions, general structures, coastal transects, and some feature names.
Spatial and attribute information for coastal transect.
Grid of DFIRM panels.
National Geodetic Survey reference points (bench marks).
Public Land Survey System (range, township, and sections).
Location of roads, and political entities.
Grid of USGS 7.5-Minute Series Topographic Maps.
Base map surface water features.
Location of Coastal Barrier Resources System Areas
The DFIRM Database is compiled in conjunction with the hardcopy FIRM and the final FIS report. The specifics of the hydrologic and hydraulic analyses performed are detailed in the FIS report. The results of these studies are submitted in digital format to FEMA. These data and unrevised data from effective FIRMs are compiled onto the base map used for DFIRM publication and checked for accuracy and compliance with FEMA standards.
Metadata imported.
Feature geometry.
ESRI
Concatenation of FLD_ZONE and BFE
Added by Lee County GIS Department
Area of feature in internal units squared.
ESRI
BFE (STATIC_BFE or BFE derived from BFE lines)
Added by Lee County GIS Department
Internal feature number.
ESRI
The DFIRM Database 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.
Appendix L of FEMA's Guidelines and Specifications for FEMA Flood Hazard Mapping Partners contains a detailed description of each attribute code and a reference to other relevant information. The following tables are included in this data set: l_comm_info study_info s_bfe s_cbrs s_cst_tsct_ln s_firm_pan s_fld_haz_ar s_fld_haz_ln s_gen_struct s_perm_bmk s_plss_ar s_plss_ln s_pol_ar s_pol_ln s_quad_index s_trnsport_ln s_wtr_ln s_xs s_label_pt s_label_ld l_stn_start l_mt1_lomc
P.O. Box 1038
Data requests must include the full name of the community or county and the FIRM panel number(s) or the 7.5- minute series quadrangle sheet area(s) covered by the request.
No warranty expressed or implied is made by FEMA regarding the utility of the data on any other system nor shall the act of distribution constitute any such warranty. FEMA will warrant the delivery of this product in a computer-readable format, and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer input peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustment of credit must be made within 90 days from the date of this shipment from the ordering site.
500 C Street, S.W.