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Special Flood Hazard Area (SFHA) Zone Definition

This table is for use with the MassGIS Q3 Flood Zones theme. It describes the attributes of the ZONE field.

ZONEs symbolized in MassGIS coverage ZONEs not symbolized in MassGIS coverage

Zone Name ZONE SFHA SYMBOL Description
Zone V V In 1 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
Zone VE VE In 2 An area inundated by 100-year flooding with velocity hazard (wave action); BFEs have been determined.
Zone A A In 3 An area inundated by 100-year flooding, for which no BFEs have been determined.
Zone AE AE In 4 An area inundated by 100-year flooding, for which BFEs have been determined.
Zone AO AO In 5 An area inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average depths have been determined; flood depths range from 1 to 3 feet.
Zone AO (Alluvial Fan) AOVEL In 6 An alluvial fan inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average flood depths and velocities have been determined; flood depths range from 1 to 3 feet.
Zone AH AH In 7 An area inundated by 100-year flooding (usually an area of ponding), for which BFEs have been determined; flood depths range from 1 to 3 feet.
Zone A99 A99 In 8 An area inundated by 100-year flooding, for which no BFEs have been determined. This is an area to be protected from the 100-year flood by a Federal flood protection system under construction.
Zone D D Out 9 An area of undetermined but possible flood hazards.
Zone AR AR In 10 An area inundated by flooding, for which BFEs or average depths have been determined. This is an area that was previously, and will again, be protected from the 100-year flood by a Federal flood protection system whose restoration is Federally funded and underway.
Zone X (500-year) X500 Out 11 An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
Zone X X Out 12 An area that is determined to be outside the 100- and 500-year floodplains.
100-year Flood Discharge Contained in Channel 100IC In 13 An area where the 100-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. BFEs are not shown in this area, although they may be reflected on the corresponding profile.
500-year Flood Discharge Contained in Channel 500IC Out 14 An area where the 500-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown.
Floodway Contained in Channel FWIC In 15 An area where the floodway is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. BFEs are not shown in this area, although they may be reflected on the corresponding profile.
Flood Prone Area FPQ In 16 An area designated as a "Flood Prone Area" on a map prepared by USGS and the Federal Insurance Administration. This area has been delineated based on available information on past floods. This is an area inundated by 100-year flooding for which no BFEs have been determined.
Area in SFHA IN In 17 An area designated as within a "Special Flood Hazard Area" (or SFHA) on a FIRM. This is an area inundated by 100-year flooding for which BFEs or velocity may have been determined. No distinctions are made between the different flood hazard zones that may be included within the SFHA. These may include Zones A, AE, AO, AH, A99, AR, V, or VE.
Area Outside SFHA OUT Out 18 An area designated as outside a "Special Flood Hazard Area"(or SFHA) on a FIRM. This is an area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; an area protected by levees from 100-year flooding; or an area that is determined to be outside the 100- and 500-year floodplains. No distinctions are made between these different conditions. These may include both shaded and unshaded areas of Zone X.
Area Not Included ANI Out 0 An area that is located within a community or county that is not mapped on any published FIRM.
Area of Undesignated Flood Hazard UNDES Out 0 A body of open water, such as a pond, lake ocean, etc., located within a community's jurisdictional limits, that has no defined flood hazard.

This table was modified from "TABLE 4: SFHA Zone Definition" in data provided by FEMA.

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May 19, 2000
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