Federal Emergency Management Agency
20090616
DIGITAL FLOOD INSURANCE RATE MAP DATABASE, JOHNSON COUNTY, TENNESSEE AND INCORPORATED AREAS
FEMA-DFIRM-Final
Washington, DC
Federal Emergency Management Agency
http://www.fema.gov/msc
Federal Emergency Management Agency
20090616
FEMA CASE 07-04-4924S
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).
In addition to the preceding, required text, the Abstract should also describe the projection and coordinate system as well as a general statement about horizontal accuracy.
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.
20090616
FIRM and FIS Effective Date
Unknown
-178.227818
-66.949827
71.390482
18.910791
ISO 19115 Topic Category
hydrology
environment
inlandWaters
structure
transportation
elevation
FEMA NFIP Topic Category
DFIRM
FIRM
FEMA Flood Hazard Zone
DFIRM Database
Special Flood Hazard Area
Digital Flood Insurance Rate Map
CBRS
Coastal Barrier Resources System
Riverine Flooding
Coastal Flooding
NFIP
Base Flood Elevation
SFHA
Flood Insurance Rate Map
Floodway
None
REGION 04
STATE TN
COUNTY JOHNSON
COUNTY-FIPS 091
COMMUNITY JOHNSON COUNTY UNINCORPORATED AREAS
FEMA-CID 47091C
COMMUNITY JOHNSON COUNTY UNINCORPORATED AREAS
FEMA-CID 470230
COMMUNITY CITY OF MOUNTAIN CITY
FEMA-CID 470275
Restricted
Access restricted without authorization from the State of Tennessee Department of Finance and Administation GIS Department. Please see point of contact to retrieve data.
Federal Emergency Management Agency
mailing
500 C Street, S.W.
Washington
District of Columbia
20472
USA
1-800-358-9616
miphelp@mapmodteam.com
Federal Emergency Management Agency
2008
Flood Insurance Rate Map, JOHNSON County, Tennessee and Incorporated Areas
map
Washington, DC
Federal Emergency Management Agency
http://www.fema.gov/msc
Federal Emergency Management Agency
2008
Flood Insurance Study, JOHNSON County, Tennessee and Incorporated Areas
document
Washington, DC
Federal Emergency Management Agency
http://www.fema.gov/msc
Federal Emergency Management Agency
2008
Raster FIRM, JOHNSON County, Tennessee and Incorporated Areas
raster digital data
Washington, DC
Federal Emergency Management Agency
http://www.fema.gov/msc
The DFIRM Database consists of community based 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 community based 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 community based 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.
Federal Emergency Management Agency
20090616
Flood Insurance Study, JOHNSON County, Tennessee and Incorporated Areas
The sources of authority for this Flood Insurance Study are the National Flood Insurance Act
of 1968 and the Flood Disaster Protection Act of 1973.
This FIS was prepared to include the incorporated communities within Johnson County in a countywide format.
The authority and acknowledgements for Johnson County, Tennessee, including the incorporated communities is not
available since FIS reports have never been published for these communities. For this countywide FIS, new hydrologic
and hydraulic analyses were performed by Watershed IV Alliance (the Study Contractor), for the Federal Emergency
Management Agency (FEMA), under Contract No. EMA-2002-CO-0011A. Task Order No. 016. Base map information shown on this
FIRM was derived from multiple sources. Base map information for Johnson County and all incorporated communities within
Johnson County was provided in digital format by the State of Tennessee. This information was compiled from tax maps
and aerial photography. The digital FIRMs were produced in Universal Transverse Mercator coordinates referenced to the
North American Datum of 1988 and the Clarke 1866 spheroid.
paper
2008
publication date
STUDY1
Spatial and attribute information, floodplain widths, BFEs, floodplain location, general structures, FIRM Panel Neatlines, cross sections
USGS
20020101
USGS Quad Index
online
20020101
publication date
BASE1
USGS Quad Index
NOAA, NGS
20061129
Benchmarks
online
20061129
publication date
BASE2
Benchmarks
State of Tennessee Department of Finance and Administration GIS Department
20061030
Incorporated Communities
online
20061030
publication date
BASE3
Incorporated Communities
State of Tennessee Department of Finance and Administration GIS Department
20061030
County Boundary
online
20061030
publication date
BASE6
County Boundary
State of Tennessee Department of Finance and Administration GIS Department
20061030
Transportation
online
20061030
publication date
BASE4
Transportation
State of Tennessee Department of Finance and Administration GIS Department
20061030
Hydrology
online
20061030
publication date
BASE5
Hydrology
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.
STUDY1
BASE1
BASE2
BASE3
BASE4
BASE5
BASE6
20090616
State Plane Coordinate System 1983
4100
35.25
36.4166667
-86.000000
34.333333
1968500.00000
0.0
coordinate pair
.304801
.304801
survey feet
North American Datum of 1983
Geodetic Reference System 80
6378137
298.25
North American Vertical Datum of 1988
10
feet
Attribute values
S_BFE
Location and attributes for base flood elevations lines shown on DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_FIRM_Pan
Location and attributes for DFIRM hardcopy map panels
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Fld_Haz_Ar
Location and attributes flood insurance risk zones on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Fld_Haz_Ln
Location and attributes for boundaries of flood insurance risk zones on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Gen_Struct
Location and attributes for flood control structures shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Label_Ld
Location and attributes for leader lines on transportation and hydrography labels shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Label_Pt
Location and attributes for transportation and hydrography labels shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Perm_Bmk
Location and attributes for bench marks on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Pol_Ar
Location and attributes for political jurisdictions shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Pol_Ln
Location and attributes for political boundaries shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Quad_Index
Location and attributes for USGS quadrangle maps covering the DFIRM area.
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Trnsport_Ln
Location and attributes for roads, railroads and other transportation features shown on the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Wtr_Ar
Location and attributes for hydrography features shown on DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_Wtr_Ln
Location and attributes for hydrography features shown on DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
S_XS
Location and attributes for cross-section lines in the area covered by the DFIRM
FEMA Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L: Guidance for Preparing Draft Digital Data and DFIRM Databases (available at http://www.fema.gov/fhm/dl_cgs.shtm)
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 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 S_QUAD_INDEX S_FIRM_Pan S_Fld_Haz_Ar S_Fld_Haz_Ln S_Label_Ld S_Label_Pt S_Perm_Bmk S_Pol_Ar S_Pol_Ln S_Trnsport_Ln S_Wtr_Ln Study_Info
Files with Not Populated (NP) values in attributes: s_transport_ln - label_type field has NP values where attribute information was not provided
State of Tennessee Department of Finance and Administration GIS Department
Dennis Pederson
Director of GIS Services
mailing and physical address
312 8th Ave. North Suite 1600
Nashville
TN
37243
USA
615-741-1534
dennis.pederson@state.tn.us
8am - 4pm
Contact State of Tennessee Department of Finance and Administration GIS Department
See point of contact
ARCE
http://gis.state.tn.us/mapping.html
ESRI Shapefile
http://www.fema.gov/msc
MapInfo Interchange file (MIF)
http://www.fema.gov/msc
ARCE
CD-ROM
ISO 9660
ESRI Shapefile
CD-ROM
ISO 9660
MapInfo Interchange file (MIF)
CD-ROM
ISO 9660
Contact Distributor
20090616
Daryle Fontenot
Watershed IV Alliance
Project Manager
mailing and physical address
6201 Fairview Road Suite 400
Charlotte
NC
28210
USA
704-643-0108
dfontenot@watershedconcepts.com
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
http://hazards.fema.gov
http://www.epsg.org
FEMA NFIP Metadata Content and Format Standard