Digital Flood Insurance Database Submission for White County, AR ,USA

Resource lineage description

source

source description  Source Contribution: Spatial and attribute information, floodplain widths, floodplain location.Source Type paper

source citation

Title Flood Insurance Study Report, White County, USA and Incorporated areas.

publication  Date   2012-05-02

cited responsible party - originator

organisation Name  Federal Emergency Management Agency.

source

source description  Source Contribution: S_FIRM_PAN represents spatial and attribute information for the Flood Insurance Rate Map (FIRM) panel area for White County, AR. S_POL_LN represents the political boundaries and metropolitan areas in line format for White County, AR. S_PLSS_LN file represents Public Land Survey System (PLSS) section boundaries as polylines in White County, AR. S_GEN_STRUCT contains information about the hydraulic structures within the White County, AR. S_FLD_HAZ_AR contains information about the flood hazard polygon features for White County, AR. S_FLD_HAZ_LN contains information about the flood hazard line features for White County, AR. S_PROFIL_BASLN contains information about the streamlines used to develop the effective profile information. S_BFE file represents Base Flood Elevations as polylines in White County, AR. S_STN_START file represents station start locations for the flood profile measurements in White County, AR. L_MT1_LOMC file represents the location and information used and incorporated as Letters of Map Change in White County, AR.Source Type MIP

source citation

Title DFIRM Database for White County, AR, USA and Incorporated Areas

publication  Date   2012-05-02

cited responsible party - originator

organisation Name  FTN Associates Ltd

source

source description  Source Contribution: S_QUAD_INDEX represents spatial and attribute information for the index of the USGS 7.5-Minute Series Topographic Quadrangle Map boundaries for White County, AR.Source Type DIGITAL

source citation

Title S_QUAD_INDEX for White County, AR

publication  Date   2012-05-02

cited responsible party - publisher

organisation Name  U.S. Geological Survey

Contact information

Address

, Reston, VA

cited responsible party - originator

organisation Name  U.S. Geological Survey (USGS)

source

source description  Source Contribution: S_POL_AR represents the political boundaries and metropolitan areas in polygon format for White County, AR. Road line features in S_TRNPORT_LN which represents the location and attributes for road features shown on the DFIRM. Railroad line features in S_TRNSPORT_LN which represents the location and attributes for railroad features shown on the DFIRM. Airport line features in S_TRNPORT_LN which represents the location and attributes for airport features shown on the DFIRM. S_PLSS_AR file represents location and attributes of sections, townships and ranges shown on the DFIRM.Source Type DIGITAL

source citation

Title Political boundaries; S_Trnsport_Ln_ACF_Rds, Railroads, Airports; and Public Land Survey System for White County, AR

publication  Date   2012-05-02

cited responsible party - publisher

organisation Name  Arkansas Geographic Information Office

Contact information

Address

, Little Rock, Arkansas

cited responsible party - originator

organisation Name  Arkansas Geographic Information Office/State Land Information Board

cited responsible party -

organisation Name  

Contact information

Linkage for online resource

URL: http://www.gis.state.ar.us

source

source description  Source Contribution: S_PERM_BMK shapefile provides a base of reference for latitude, longitude and height throughout White County, AR.Source Type DIGITAL

source citation

Title S_PERM_BMK for White County, AR

publication  Date   2012-05-02

cited responsible party - publisher

organisation Name  NOAA, National Geodetic Survey (NGS)

Contact information

Address

, Silver Spring, MD

cited responsible party - originator

organisation Name  NOAA, National Geodetic Survey (NGS)

source

source description  Source Contribution: S_WTR_AR file represents the location and attributes for hydrography features (water polygons) shown on the DFIRM. S_WTR_LN represents all Flood Insurance Study stream centerlines for White County, AR.Source Type DIGITAL

source citation

Title HIGH RESOLUTION: NATIONAL HYDROGRAPHY DATASET WATERBODY FEATURES

publication  Date   2012-05-02

cited responsible party - publisher

organisation Name  U.S. Geological Survey

Contact information

Address

, Reston, Virginia

cited responsible party - originator

organisation Name  National Hydrography Dataset (NHD)

AbsoluteExternalPositionalAccuracy

name Of Measure Horizontal Positional Accuracy Report

evaluation Method Description  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 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 DFIRM database was also performed.

AbsoluteExternalPositionalAccuracy

name Of Measure Vertical Positional Accuracy Report

evaluation Method Description  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 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 DFIRM database was also performed.

Completeness Commission

evaluation Method Description  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.

Completeness Omission

evaluation Method Description  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.

ConceptualConsistency

measure Description  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.