West Virginia GIS Technical Center
20100826
Statewide 100-year Floodplain Polygons for West Virginia
vector digital data
<http://wvgis.wvu.edu/data/dataset.php?action=search&ID=128>
The statewide 100-year floodplain polygon data set was first compiled in 2006 from the best flood data currently available from the Federal Emergency Management Agency (FEMA). Data sources include Q3 digital floodplains, Draft DFIRM, Preliminary DFIRM and Effective DFIRM.
This data set was developed primarily for use in the West Virginia GIS Technical Center's web-based flood hazard determination tool, which enables users to make initial determinations regarding the location of specific properties in or out of areas of 1% annual chance flooding.
20100826
publication date
As needed
-82.698657
-77.676669
40.452177
37.165440
ISO 19115 Topic Category
inlandWaters
FEMA NFIP Topic Category
FEMA Flood Hazard Zone
Special Flood Hazard Area
Riverine Flooding
Flood Insurance Rate Map
FIRM
DFIRM
Floodway
None
flooding
flood
floodplain
flood hazard determination tool
flood hazard determination map
advisory flood height
modeled approximate A zone
none
flooding
riverine flooding
flood hazard area
None
West Virginia
None
This data is derived from effective, preliminary and draft FEMA flood data, but is not intended to replace official FEMA publications. Acknowledgement of FEMA and the West Virginia GIS Technical Center will be appreciated in presentations or publications that make use of this data.
Eric Hopkins
West Virginia GIS Technical Center
Lead GIS Specialist
mailing
West Virginia University
Department of Geology and Geography
330 Brooks Hall
PO Box 6300
Morgantown
West Virginia
26506
USA
(304) 293-9463
ehopkins@wvu.edu
9:00 A.M - 5:00 P.M.
West Virginia GIS Technical Center
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.6.1500
Federal Emergency Management Agency (FEMA)
2008
Effective Countywide DFIRMs for West Virginia
vector digital data
Washington, DC, USA
Federal Emergency Management Agency
DFIRM dates are 2008 and earlier
<http://msc.fema.gov>
Federal Emergency Management Agency (FEMA)
1988
Digital Q3 Flood Data
vector digital data
Washington, DC, USA
Federal Emergency Management Agency (FEMA)
<http://www.fema.gov/hazard/map/q3.shtm>
FEMA Cooperating Technical Partners (CTPs), Flood mapping contractors
Unpublished Material
Draft DFIRM Data
vector digital data
<ftp://ftp.wvgis.wvu.edu/pub/Clearinghouse/water_resources/DFIRM-lite>
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 Flood Insurance Studies (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 databases was also performed. Draft DFIRM data has not been independently tested. 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 reports that accompany the Effective DFIRM databases. 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 theDFIRM database S_XS table match the regulatory elevations shown in the FIS report. This data does not include cross section (XS) or BFE information.
The floodplains depicted in this data have been compared to the Effective DFIRM, Q3, Preliminary DFIRM or Draft DFIRM source material to check for alignment errors or omissions. Effective DFIRMs have been subjected to more thorough analysis and checking for spatial agreement of features.
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 National Flood Insurance Program (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.
Horizontal accuracy of Effective DFIRM data 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.
Dataset compiled from Effective DFIRM, Draft DFIRM, and Q3 flood hazard polygon data
DFIRM, Draft, Q3
2006
Incorporated new Effective DFIRM and Draft DFIRM data. Zone A, Zone AE, and Zone AO polygons were copied into the existing statewide data set.
DFIRM, Draft DFIRM, Q3
200807
Incorporated new Effective and Preliminary DFIRM data. Zone A, Zone AE, and Zone AO polygons were copied into the existing statewide data set.
DFIRM, Preliminary DFIRM, Draft DFIRM, Q3
20100826
Incorporated new model-based Approximate A Zone (Advisory Flood Height) data from AMEC Earth and Environmental for five counties into the new statewide floodplain data set: Marion, Harrison, Mineral, Mingo and Wayne. The floodplain polygons in these five counties match the water surface and depth grid raster data provided by AMEC and incorporated into the WV Flood Hazard Determination Tool.
modeled Approximate A Zone, Advisory Flood Height (AFH)
Note that we need to add source elements that describe the items listed above under Source_Used_Citation.
2010826
Vector
G-polygon
2052
Universal Transverse Mercator
17
0.999600
-81.000000
0.000000
500000.000000
0.000000
coordinate pair
0.001024
0.001024
meters
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
North American Vertical Datum of 1988
1.000000
feet
Explicit elevation coordinate included with horizontal coordinates
VECTUSR.femaAll5
Location and attributes for floodplain polygons
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>)
OBJECTID
Internal feature number
ESRI
ZONE
Special Flood Hazard Area (SFHA)
DFIRM, Draft, Q3
SHAPE
Feature geometry
ESRI
TYPE
Data source, i.e. Effective, Preliminary, Draft, Q3
WVGISTC
West Virginia GIS Technical Center
Eric Hopkins
mailing
West Virginia University
Department of Geology and Geography
330 Brooks Hall
PO Box 6300
Morgantown
West Virginia
26506
USA
(304) 293-9463
ehopkins@wvu.edu
9:00 A.M - 5:00 P.M.
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 the West Virginia GIS Technical Center regarding the utility of the data on any other system nor shall the act of distribution constitute any such warranty.
ESRI Shapefile
1
<http://wvgis.wvu.edu/data/dataset.php?action=search&ID=373>
none
20100914
West Virginia GIS Technical Center
Eric Hopkins
mailing
West Virginia University
Department of Geology and Geography
330 Brooks Hall
PO Box 6300
Morgantown
West Virginia
26506
USA
(304) 293-9463
ehopkins@wvu.edu
9:00 A.M - 5:00 P.M.
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
none
none
<http://www.esri.com/metadata/esriprof80.html>
ESRI Metadata Profile