FLOODPLAIN, GILES COUNTY, VIRGINIA, USA


Identification Information:
Citation:
Citation Information:
Originator: Center for Geospatial Information Technology at Virginia Tech
Publication Date: 20080501
Title: FLOODPLAIN, GILES COUNTY, VIRGINIA, USA
Geospatial Data Presentation Form: FEMA-DFIRM-Floodplain
Publication Information:
Publication Place: Washington, DC
Publisher: Federal Emergency Management Agency
Online Linkage: http://hazards.fema.gov
Larger Work Citation:
Citation Information:
Originator: Federal Emergency Management Agency
Publication Date: 20080501
Title: FEMA CASE 06-03-B636S
Description:
Abstract: The Floodplain Mapping/Redelineation study deliverables depict and quantify the flood risks for the study area. 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 Floodplain Mapping/Redelineation flood risk boundaries are derived from the engineering information 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).
Purpose: The objective of the Floodplain Mapping/Redelineation data submission is to archive the flood boundary and redelineation data for a study in a database such that it can be revised and used with minimum effort in future flood insurance studies or map revisions. This digital data is produced for the purposes of updating/creating a DFIRM database.
Time Period of Content:
Time Period Information:
Single Date/Time:
Calendar Date: 19801215
Currentness Reference: FIRM and FIS Effective Date
Status:
Progress: Complete
Maintenance and Update Frequency: Unknown
Spatial Domain:
Bounding Coordinates:
West Bounding Coordinate: -81.19
East Bounding Coordinate: -80.31
North Bounding Coordinate: 37.56
South Bounding Coordinate: 37.07
Keywords:
Theme:
Theme Keyword Thesaurus: ISO 19115 Topic Category
Theme Keyword: hydrology
Theme Keyword: environment
Theme Keyword: inlandWaters
Theme:
Theme Keyword Thesaurus: FEMA NFIP Topic Category
Theme Keyword: Floodplain Mapping
Theme Keyword: Digital Flood Insurance Rate Map
Theme Keyword: DFIRM
Theme Keyword: FIRM
Theme Keyword: FEMA Flood Hazard Zone
Theme Keyword: DFIRM Database
Theme Keyword: Special Flood Hazard Area
Theme Keyword: CBRS
Theme Keyword: Coastal Barrier Resources System
Theme Keyword: Riverine Flooding
Theme Keyword: Coastal Flooding
Theme Keyword: NFIP
Theme Keyword: Base Flood Elevation
Theme Keyword: SFHA
Theme Keyword: Flood Insurance Rate Map
Theme Keyword: Floodway
Place:
Place Keyword Thesaurus: None
Place Keyword: REGION 3
Place Keyword: STATE VA
Place Keyword: COUNTY Giles
Place Keyword: COUNTY-FIPS 071
Place Keyword: COMMUNITY Giles County (and incorporated areas)
Place Keyword: FEMA-CID 51071C
Access Constraints: None
Use Constraints: Acknowledgement of FEMA would be appreciated in products derived from these data. This digital data is produced for the purposes of updating/creating a DFIRM database.
Data Quality Information:
Logical Consistency 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.
Completeness Report: Data contained in the Floodplain Mapping and Redelineation 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.
Lineage:
Source Information:
Source Citation:
Citation Information:
Originator: Federal Emergency Management Agency
Publication Date: Unknown
Title: Flood Insurance Study, Giles County, VA, dated 19801215
Type of Source Media: paper
Source Time Period of Content:
Time Period Information:
Single Date/Time:
Calendar Date: 19801215
Source Currentness Reference: FIS and FIRM Effective Date
Source Citation Abbreviation: FIS1
Source Contribution: Spatial and attribute information for Base Flood Elevations (BFEs) and floodway widths.
Source Information:
Source Citation:
Citation Information:
Originator: Center for Geospatial Information Technology
Publication Date: 20080501
Title: New Countywide Flood Hazard Data
Other Citation Details: Contract No. EMP-2005-GR 3718
Source Scale Denominator: 6000
Type of Source Media: DVD-ROM
Source Time Period of Content:
Time Period Information:
Single Date/Time:
Calendar Date: 20080501
Source Currentness Reference: publication date
Source Citation Abbreviation: STUDY1
Source Contribution: Spatial and attribute information for new countywide FIRM panels. BFEs converted from NGVD29 found on the effective FIS flood profiles (FIS1) to NAVD88.
Process Step:
Process Description: Floodplain Mapping and Redelineation datasets are 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.
Process Date: 20080501
Spatial Reference Information:
Horizontal Coordinate System Definition:
Planar:
Grid Coordinate System:
Grid Coordinate System Name: State Plane Coordinate System 1983
State Plane Coordinate System:
SPCS Zone Identifier: 4502
Lambert Conformal Conic:
Standard Parallel: 36.7666666666667
Standard Parallel: 37.9666666666667
Longitude of Central Meridian: -78.5
Latitude of Projection Origin: 36.3333333333333
False Easting: 11482916.6666667
False Northing: 3280833.33333333
Planar Coordinate Information:
Planar Coordinate Encoding Method: coordinate pair
Coordinate Representation:
Abscissa Resolution: 0.304800609601219
Ordinate Resolution: 0.304800609601219
Planar Distance Units: international feet
Geodetic Model:
Horizontal Datum Name: North American Datum of 1983
Ellipsoid Name: Geodetic Reference System 80
Semi-major Axis: 6378137.0
Denominator of Flattening Ratio: 298.26
Entity and Attribute Information:
Detailed Description:
Entity Type:
Entity Type Label: S_Fld_Haz_Ar
Entity Type Definition: Location and attributes for flood insurance risk zones
Entity Type Definition Source: 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)
Detailed Description:
Entity Type:
Entity Type Label: S_Fld_Haz_Ln
Entity Type Definition: Location and attributes for boundaries of flood insurance risk zones
Entity Type Definition Source: 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)
Overview Description:
Entity and Attribute Overview: The Floodplain Mapping and Redelineation datasets contain both spatial and attribute information. These data together represent the current flood risk for the subject area as identified by FEMA. The attribute tables may include SFHA locations, flood zone designations, BFEs, political entities, cross-section locations, FIRM panel information, and other data related to the NFIP.
Entity and Attribute Detail Citation: 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.
Distribution Information:
Distributor:
Contact Information:
Contact Organization Primary:
Contact Organization: Federal Emergency Management Agency
Contact Address:
Address Type: mailing
Address: 500 C Street, S.W.
City: Washington
State or Province: District of Columbia
Postal Code: 20472
Country: USA
Contact Voice Telephone: 1-877-336-2627
Contact Electronic Mail Address: miphelp@mapmodteam.com
Distribution Liability: 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.
Standard Order Process:
Digital Form:
Digital Transfer Information:
Format Name: ESRI Shapefile
Digital Transfer Option:
Online Option:
Computer Contact Information:
Network Address:
Network Resource Name: http://hazards.fema.gov
Fees: Contact Distributor
Available Time Period:
Time Period Information:
Single Date/Time:
Calendar Date: 20080501
Metadata Reference Information:
Metadata Date: 20080501
Metadata Contact:
Contact Information:
Contact Person Primary:
Contact Person: Rachael Herman
Contact Organization: Center for Geospatial Information Technology at Virginia Tech
Contact Address:
Address Type: mailing
Address: 2060 Torgersen Hall
City: Blacksburg
State or Province: Virginia
Postal Code: 24061
Country: USA
Contact Voice Telephone: 1-540-231-8338
Contact Electronic Mail Address: heltz@vt.edu
Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata Standard Version: FGDC-STD-001-1998
Metadata Extensions:
Online Linkage: http://hazards.fema.gov
Online Linkage: http://www.epsg.org
Profile Name: FEMA NFIP Metadata Content and Format Standard