West Virginia GIS Technical Center
20130410
Statewide 100-year Floodplain Polygons for West Virginia
Vector Digital Data Set (Polygon)
Morgantown, WV
West Virginia GIS Technical Center
http://wvgis.wvu.edu/data/dataset.php?ID=373
http://www.wvgis.wvu.edu
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 for the current version include the National Flood Hazard Layer (NFHL), Effective DFIRM databases, Preliminary DFIRM databases and Q3 digital floodplain shapefiles.
This data set was developed primarily for use in the West Virginia GIS Technical Center's web-based Flood Tool, which enables users to estimate flood risk and the "in" or "out" status of specific properties or structures relative to areas (Flood Zones) of 1% annual chance flooding.
20130410
publication date
As needed
-82.64474294
-77.725291015
40.638810501
37.206718893
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
riverine flooding
flood hazard area
EPA GIS Keyword Thesaurus
Disaster
Emergency
Hazards
Risk
Surface Water
Water
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
GIS Specialist
mailing
West Virginia University
Department of Geology and Geography
Morgantown
West Virginia
26506
(304) 293-9463
ehopkins@wvu.edu
West Virginia GIS Technical Center
Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 10.1 (Build 3035) Service Pack 1 (Build 3143)
Federal Emergency Management Agency (FEMA)
20121231
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. 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 set does not include cross section (XS) or BFE information.
The floodplains depicted in this data have been compared to the NFHL, Effective DFIRM, Preliminary DFIRM or Q3 source material to check for alignment errors or omissions. Effective DFIRMs, including the NFHL, which is compiled from Effective DFIRM data, have been subjected, during production and after delivery, 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.
The DFIRM Databases used to compile this data set consist 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 of the countywide DFIRM databases 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
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.
200807
Incorporated new Effective and Preliminary DFIRM data. Zone A, Zone AE, and Zone AO polygons were copied into the existing statewide data set.
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. This will not be the case in counties where the DFIRM became effective before the new Approximate A Zone data was published.
20100826
Incorporated new Effective and Preliminary DFIRM data for eight counties: Effective: Barbour, Doddridge, Nicholas, Pocahontas; Preliminary: Greenbrier, Roane, Webster, Wirt. Zone A, Zone AE, and Zone AO polygons were copied into the existing statewide data set.
20120206
Incorporated new model-based Approximate A Zone (Advisory Flood Height) data from AMEC Earth and Environmental for eight counties into the new statewide floodplain data set: Fayette, Greenbrier, Kanawha, Logan, McDowell, Mercer, Raleigh, Wyoming. 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. This will not be the case in counties where the DFIRM became effective before the new Approximate A Zone data was published.
20120206
Incorporated new Effective and Preliminary DFIRM data for seventeen counties: Effective: Greenbrier, Harrison, Marion, Mingo, Preston, Putnam, Ritchie, Roane, Taylor, Webster, Wirt; Preliminary: Boone, Clay, Lincoln, Mason, Pleasants, Wood. Zone A, Zone AE, and Zone AO polygons were copied into the existing statewide data set.
20130228
Vector
G-polygon
2436
WGS 1984 Web Mercator Auxiliary Sphere (ESRI Full Name: WGS_1984_Web_Mercator_Auxiliary_Sphere)
1.0
0.0
0.0
0.0
0.0
coordinate pair
0.6096
0.6096
Meter
D_WGS_1984
WGS_1984
6378137.0
298.257223563
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.
West Virginia GIS Technical Center and FEMA Guidelines and Specifications for Digital Flood Mapping.
West Virginia GIS Technical Center
Eric Hopkins
GIS Specialist
mailing and physical
WVU Dept. of Geology and Geography
Brooks Hall rm 330
Morgantown
WV
26506-6300
(304) 293-9463
Eric.Hopkins@mail.wvu.edu
Downloadable Data
Although these data have been processed successfully on a computer system at the West Virginia GIS Technical Center, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions or intended use. The West Virginia GIS Technical Center shall not be held liable for improper or incorrect use of the data described and/or contained herein.
Vector Digital Data Set (Polygon)
1
<http://wvgis.wvu.edu/data/dataset.php?action=search&ID=373>
none
20130422
20140914
West Virginia GIS Technical Center
Eric Hopkins
GIS Specialist
mailing and physical
WVU Dept. of Geology and Geography
Brooks Hall rm 330
Morgantown
WV
26506-6300
(304) 293-9463
Eric.Hopkins@mail.wvu.edu
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