FEMA Form 81-92, SEP 07 MT-EZ Form 7 of 8
1. Zone A Flooding – If the property is located in Zone A, an area of approximate flooding with no BFEs determined,
determine a BFE. Consult with a Federal, State, or local government agency to determine if that agency has
developed a BFE. Such agencies include the U.S. Army Corps of Engineers; the U.S. Geological Survey; the State’s
Department of Natural Resources, Department of Environmental Quality, or Department of Transportation; or the
local Planning and Zoning Department. If a BFE has not previously been developed, consult DHS-FEMA 265,
Managing Floodplain Development in Approximate Zone A Areas, A Guide for Obtaining and Developing Base
(100-Year) Flood Elevations, available on the DHS-FEMA Flood Hazard Mapping website at
http://www.fema.gov/pdf/fhm/frm_zna.pdf
. This publication is an excellent resource that details the appropriate
methods for determining BFEs in SFHAs designated Zone A. To obtain a printed copy of this publication, or to
obtain additional information about developing BFEs, contact the DHS-FEMA Map Assistance Center, toll free, at
1-877-FEMA MAP (1-877-336-2627). If the property is greater than 50 lots or 5 acres, whichever is the lesser, the
engineer or surveyor must determine a BFE in accordance with Paragraph 60.3(b)(3) of the NFIP regulations,
available online at
http://www.access.gpo.gov/nara/cfr/waisidx_03/44cfr60_03.html.
• Shallow Flooding (Zone AH) – For a property located in Zone AH, an area of shallow flooding, use the BFE
shown on the FIRM. If different elevations appear within the same SFHA, the BFE is obtained by linear
interpolation between two adjacent BFE lines.
• Shallow/Sheet Flooding (Zone AO) – For a property located in Zone AO, the characteristics of the Zone AO area
shown on the NFIP map will determine the appropriate methodology to be used to develop the BFE for the property.
If the flooding is conveyed by the street, provide the highest top of curb or crown of street elevation (whichever is
higher) along the property line and add this to the depth of flooding. The lowest adjacent grade elevation must be
above the curb or street elevation by an amount equal to or greater than the depth of flooding shown on the NFIP
map. If the entire property is inundated by the SFHA and the flow is not conveyed by the street, add the depth of
flooding to the average surrounding grade. If the property is partially inundated by the SFHA and the street does not
convey the flow, add the depth of flooding to the lowest lot elevation. Along with the information required for one
of the above-mentioned methods, provide sufficient certified topographic information, including flow paths, to show
that the structure is located on high ground relative to the depth indicated on the NFIP map.
Number 5 – Elevation Information
Lowest Adjacent Grade (LAG) to the Structure
– For requests involving a structure, provide the LAG elevation, to the
nearest 0.1 foot. If the FIRM shows BFEs in meters, the accuracy of the LAG elevation must be to the nearest 0.1 meter.
Lowest Lot Elevation
– For requests involving property, or a portion thereof, not a structure, provide the lowest lot elevation
to the nearest 0.1 foot. If the FIRM shows BFEs in meters, the accuracy of the lowest lot elevation must be to the nearest 0.1
meter.
Elevation Datum – Provide the elevation datum (e.g., National Geodetic Vertical Datum of 1929, North American Vertical
Datum of 1988 or other specified) for which the property elevations shown on the form are referenced. If the datum being
referenced is different than the datum used to produce the effective FIS, provide the datum conversion.
Subsidence or Uplift
– Land subsidence is the lowering of the ground as a result of water, oil, gas extraction, as well as other
phenomena such as soil compaction, decomposition of organic material, and tectonic movement. Periodically, the National
Geodetic Survey relevels some benchmarks to determine new elevations above the National Geodetic Vertical Datum of
1929 or above the North American Vertical Datum of 1988; however, not all benchmarks are releveled each time.
Check “yes” if the area of the property is in an area of subsidence or uplift, and provide the date of the current releveling;
check “no” if the area of the property is not in an area of subsidence or uplift. In areas experiencing ground subsidence
(e.g., Harris County, Texas, and Incorporated Areas); the most recently adjusted Elevation Reference Mark (ERM) must be
used for accurate ground and structure elevations. Consult the effective FIS report for the community where the property is
located or the local floodplain administrator for the most current ERM data.