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transportation, SFHA, hydrology, Flood Insurance Rate Map, NFIP, elevation, FIRM Database, FEMA Flood Hazard Zone, environment, Floodway, structure, FIRM, Base Flood Elevation, Special Flood Hazard Area, CBRS, Riverine Flooding,Fema, Flood, Zones, 100, Year, 500, Event, Hazard
The FIRM is the basis for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program (NFIP). Insurance applications include enforcement of the mandatory purchase requirement of the Flood Disaster Protection Act, which "... requires the purchase of flood insurance by property owners who are being assisted by Federal programs or by Federally supervised, regulated or insured agencies or institutions in the acquisition or improvement of land facilities located or to be located in identified areas having special flood hazards, " Section 2 (b) (4) of the Flood Disaster Protection Act of 1973. In addition to the identification of Special Flood Hazard Areas (SFHAs), the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered through the NFIP. The FIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The FIRM Database serves to archive the information collected during the Flood Risk Project.
The National Flood Hazard Layer (NFHL) data incorporates all Flood Insurance Rate Map (FIRM) databases published by the Federal Emergency Management Agency (FEMA), and any Letters Of Map Revision (LOMRs) that have been issued against those databases since their publication date. It is updated on a monthly basis. The FIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper FIRMs. The FIRM Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The FIRM Database is derived from Flood Insurance Studies (FISs), previously published FIRMs, flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by FEMA. The NFHL is available as State or US Territory data sets. Each State or Territory data set consists of all FIRM Databases and corresponding LOMRs available on the publication date of the data set. The specification for the horizontal control of FIRM Databases is consistent with those required for mapping at a scale of 1:12,000. This file is georeferenced to the Earth's surface using the Geographic Coordinate System (GCS) and North American Dataum of 1983 (NSRS-2007).
Edited 1/22/15
P> The zone designations shown on the FIRMs are defined below.Zone AZone A is the flood insurance rate zone used for 1-percent-annual-chance (base flood) floodplains that are determined for the Flood Insurance Study (FIS) by approximate methods of analysis. Because detailed hydraulic analyses are not performed for such areas, no Base Flood Elevations (BFEs) or depths are shown in this zone. Mandatory flood insurance purchase requirements apply.Zone AE and A1-A30Zones AE and A1-A30 are the flood insurance rate zones used for the 1-percent-annual-chance floodplains that are determined for the FIS by detailed methods of analysis. In most instances, BFEs derived from the detailed hydraulic analyses are shown at selected intervals in this zone. Mandatory flood insurance purchase requirements apply. AE zones are areas of inundation by the 1-percent-annual-chance flood, including areas with the 2-percent wave runup, elevation less than 3.0 feet above the ground and areas with wave heights less than 3.0 feet. These areas are subdivided into elevation zones with BFEs assigned. The AE zone will generally extend inland to the limit of the 1-percent-annual-chance Stillwater Flood Level (SWEL).Zone AHZone AH is the flood insurance rate zone used for areas of 1-percent-annual-chance shallow flooding with a constant water-surface elevation (usually areas of ponding) where average depths are between 1 and 3 feet. BFEs derived from detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply.Zone AOAO zones are areas of sheet-flow shallow flooding where the potential runup is less than 3.0 feet above an overtopped barrier crest (ΔR<3.0 feet). The sheet flow in these areas will either flow into another flooding source (AE zone), result in ponding (AH zone) or deterioratebecause of ground friction and energy losses and merge into the X zone. AO areas are designated with 1-, 2-, or 3-foot depths of flooding.Zone ARZone AR is the flood insurance rate zone used for areas protected by flood-control structures, such as levees, that are being restored. FEMA will consider using the Zone AR designation if the flood protection system has been deemed restorable by a federal agency in consultation with a local project sponsor; a minimum level of flood protection is still provided to the community by the system and restoration of the flood protection system is scheduled to begin within a designated time period and in accordance with a progress plan negotiated between the community and FEMA. Mandatory purchase requirements for flood insurance apply in Zone AR but the rate will not exceed that of an unnumbered Zone A, if the structure is built in compliance with Zone AR floodplain management regulations.For floodplain management in Zone AR areas, the property owner is not required to elevate existing structures when making improvements. However, new structures must be elevated (or floodproofed for nonresidential structures) so that the lowest floor, including the basement, is at least 3 feet above the highest adjacent existing grade, if the BFE does not exceed 5 feet at the proposed development site. For infill sites, rehabilitation of existing structures or redevelopment of previously developed areas, there is a 3-foot elevation requirement regardless of the depth of the BFE at the project site.The Zone AR designation will be removed and the restored flood-control system will be shown as providing protection from the base flood on the National Flood Insurance Program (NFIP) map when the restoration project is complete and all the necessary data have been submitted to FEMA.Zone A99Zone A99 is the flood insurance rate zone used for areas within the 1-percent-annual-chance floodplain that will be protected by a federal flood-protection system, where construction has reached specified statutory milestones. No BFEs or depths are shown in this zone. Mandatory flood insurance purchase requirements apply.Zone DThe Zone D designation is used for areas where there are possible but undetermined flood hazards. In areas designated as Zone D, no analysis of flood hazards has been conducted. Flood insurance is optional and available and the flood insurance rates for properties in Zone D are commensurate with the uncertainty of the flood risk.Zone V and V1 - 30Zone V and V1 - 30 designation is for coastal areas with a 1-percent or greater chance of flooding and an additional velocity hazard associated with storm waves (wave action). Because detailed hydraulic analyses are not performed for such areas, no BFEs or depths are shown in this zone. Mandatory flood insurance purchase requirements apply.Zone VEVE zones are coastal high hazard areas where wave action and/or high-velocity water can cause structural damage during the base flood. They are subdivided into elevation zones with BFEs assigned. VE zones are identified using one or more of the following criteria for the base flood conditions:The wave runup zone occurs where the (eroded) ground profile is 3.0 feet or more below the 2-percent wave runup elevationThe wave overtopping splash zone is the area landward of the crest of an overtopped barrier, in cases where the potential 2-percent wave runup exceeds the barrier crest elevation by 3.0 feet or more(ΔR>3.0 feet). (See Subsection D.2.8.2.)The breaking wave height zone occurs where 3-foot or greater wave heights could occur (this is the area where the wave crest profile is 2.1 feet or more above the total stillwater level).The primary frontal dune zone, as defined in 44 CFR Section 59.1 of the NFIP regulations.For the Pacific Coast only:The high-velocity flow zone is landward of the overtopping splash zone (or area on a sloping beach or other shore type), where the product of depth of flow times the flood velocity squared (hv2) is greater than or equal to 200 ft3/sec2.Zone B and X (shaded)Zones B and X (shaded) are areas of 0.2-percent-annual-chance floodplain, areas of 1-percent-annual-chance (base flood) sheet flow flooding with average depths of less than 1 foot, areas of base flood stream flooding with a contributing drainage area of less than 1 square mile or areas protected from the base flood by levees. No BFEs or depths are shown in this zone and insurance purchase is not requiredZones C and X (unshaded) – Protected X (protected by leeve)Zones C and X (unshaded) are flood insurance rate zones used for areas outside the 0.2-percent-annual-chance floodplain. No BFEs or depths are shown in this zone, and insurance purchase is not required.Data current as of Edited 1/22/15
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The hardcopy FIRM and FIRM Database and the accompanying FIS are the official designation of SFHAs and Base Flood Elevations (BFEs) for the NFIP. For the purposes of the NFIP, changes to the flood risk information published by FEMA may only be performed by FEMA and through the mechanisms established in the NFIP regulations (44 CFR Parts 59-78). These digital data are produced in conjunction with the hardcopy FIRMs and generally match the hardcopy map exactly. Acknowledgement of FEMA would be appreciated in products derived from these data.
Extent
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| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
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