Detailed Study, Riverine—A riverine flood hazard study that uses topographic data, channel bathymetry, and bridge or culvert opening geometry to conduct detailed hydrologic and hydraulic analyses and floodplain mapping. The analysis results in the delineation of floodplain boundaries for the 1 percent annual chance (100-year) flood, determination of BFEs or flood depths, and normally, a regulatory floodway (FEMA, 2003)

Digital Elevation Model (DEM)A file with terrain elevations recorded for the intersection of a fine-grained grid and organized by quadrangle as the digital equivalent of the elevation data on a topographic base map (FEMA, 2003)

Digital Flood Insurance Rate Map (DFIRM)A Flood Insurance Rate Map that has been prepared as a digital product, which may involve converting an existing manually produced FIRM to digital format or creating a product from new digital data sources using a geographic information system (GIS) (FEMA, 2003)

Digital Terrain Model (DTM)A land surface represented in digital form by an elevation grid or lists of three-dimensional coordinates (FEMA, 2003)

DischargeThe volume of water that passes a given location within a given period of time. Usually expressed in cubic feet per second (<http://water.usgs.gov/glossaries.html>)

Drainage AreaThe area upstream of a specific location, measured in a horizontal plane, that has a common outlet at the site for its surface runoff from precipitation that normally drains by gravity into a stream. Drainage areas include all closed basins, or noncontributing areas, within the area unless otherwise specified (<http://water.usgs.gov/glossaries.html>)

ElevationThe distance of a point above the specified surface of constant potential; the distance is the direction of gravity between the point and the surface (<http://www.ngs.noaa.gov/CORS-Proxy/Glossary/xml/NGS_Glossary.xml>)

Elevation CertificateA form on which the lowest floor elevation, lowest adjacent grade, and highest adjacent grade of a building are certified relative to the base flood elevation for the location of the building. Other descriptive information is also provided to help identify the flood risk to the building surveyed (Maune, 2007)

FIRMette—A full-scale section of a Flood Insurance Rate Map created by users online by selecting the desired area from a FIRM image. It also includes the map title block, north arrow, and scale bar (<http://msc.fema.gov/webapp/wcs/stores/servlet/FemaWelcomeView?storeId=10001&catalogId=10001&langId=-1>)

FloodA general and temporary condition of partial or complete inundation of normally dry land areas from (1) the overflow of inland or tidal waters or (2) the unusual and rapid accumulation or runoff of surface waters from any source (FEMA, 2003)

Flood Hazard Mapping Partner—Community officials; regional agency officials; state agency officials; communities, regional agencies, and state agencies participating in the FEMA Cooperating Technical Partners Program; other federal agencies; FEMA contractors; contractors of communities, regional agencies, and state agencies; community residents and property owners; other program constituents, including the U.S. Congress; insurance lending, real estate, and land development industries; and federal, state, and local disaster and emergency response officials whose combined contribution with FEMA staff obtain and maintain accurate, up-to-date flood hazard information (FEMA, 2003)

Flood Insurance Rate Map (FIRM)The insurance and floodplain management map produced by FEMA that identifies, based on detailed or approximate analyses, the areas subject to flooding during a 1 percent annual chance (100-year) flood event in a community and flood insurance risk zones. In areas studied by detailed analyses, the FIRM shows BFEs to reflect the elevations of the 1 percent annual chance flood. For many communities, when detailed analyses are performed, the FIRM also may show areas inundated by a 0.2 percent annual chance (500-year) flood and regulatory floodway areas (FEMA, 2003)



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