The Federal Emergency Management Agency (FEMA) creates Flood Insurance Rate Maps for unincorporated Lee County. Community Development staff provides important services to support Flood Insurance Rate Maps. These services verify and document:
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What is a Flood Insurance Rate Map (FIRM)?
Flood Insurance Studies are compilations of flood risk information used for community planning and development. The Federal Emergency Management Agency (FEMA) works with community leaders across the country to identify flood hazards and promote ways to reduce the impact of those and other hazards. A FIRM is a map created by FEMAs National Flood Insurance Program for floodplain management, building and flood insurance purposes. FIRMs are also referred to as Flood Maps. A FIRM will generally show a community’s base flood elevations (predicted level of flooding), flood zones and floodplain boundaries. Together, they show the risk of flooding.
High-risk flood zones, known as Special Flood Hazard Areas (SFHA), show the predicted level of flooding that could occur from the "base flood." The base flood is the type of flood that has a 1% annual chance of occurring in any given year. These SFHAs are shown on the FIRM.
Low- to moderate-risk flood zones are also shown on the FIRM but are not considered to be part of the Special Flood Hazard Area.
What is a Flood Insurance Study (FIS)?
Flood Insurance Studies are compilations of flood risk information used for community planning and development. To accompany FIRMs, Flood Insurance Study (FIS) reports are provided to communities to give background information on the FIRMs and the analyses done to produce the maps. The FIS report includes a description of the engineering methods used, flooding history, graphic profiles, flood elevation summaries, and other information. Download current versions of the FIS.
Important information regarding X zones
Floods do not read flood maps. FIRMS don’t necessarily identify all areas subject to localized flooding, particularly from local drainage sources of small size. In fact, about 40 percent of all flood insurance claims nationally come from areas designated as low- to moderate-risk areas (X zones). FIRMs are developed to show the 1 percent annual chance flood (otherwise known as the “Base Flood”) for the purposes of regulating the floodplain, and flood insurance requirements. But as we’ve learned, flooding can, and has happened anywhere it rains (examples are areas in the X zone in Houston after Harvey, or areas in North Carolina after Hurricane Matthew or Florence). X zone properties are areas where FEMA has determined that the property would not be subject to inundation by the “Base Flood” – however, the property could be subject to other flood hazards. The property could be inundated by a flood with a magnitude greater than that of the "Base Flood." Keep in mind, localized flooding is not shown on National Flood Insurance Rate maps. No matter where you live or work, some risk of flooding exists.
Flood mapping quick links:
Assessing Flood Maps
Map Panels?
The floodplain on Flood Insurance Rate Maps is identified as a Special Flood Hazard Area (SFHA). The SFHA is an area that could be inundated by a flood event with a 1 percent chance of reaching or exceeding base flood elevations in any given year. The 1 percent annual chance flood is also referred to as the base flood and you may also hear and see the term 100-year flood, however, see the below information about that term and the misconception associated with it. Link to main page.
X Zone Information - The X zone (also known as “low–risk flood zone”) is an area outside of the Special Flood Hazard Area. It’s important to know that just because an area is designated as X zone does not mean that the area will never flood. Floods don’t read flood maps. Everyone lives in a flood zone — it's just a question of whether you live in a low, moderate, or high-risk area.
Special Flood Hazard Area (SFHA)
The land area that could be covered by the floodwaters of the base flood is where the NFIP's floodplain management regulations must be enforced and where the mandatory purchase of flood insurance applies for federally backed mortgages. The requirement also extends to private mortgage companies backed by the FDIC or other federal agencies. Therefore, many private mortgage companies also require flood insurance on properties in the SFHA.
A
| Areas subject to inundation by the 1 percent annual chance flood event generally determined using approximate methodologies. Because detailed hydraulic analyses have not been performed, no Base Flood Elevations (BFEs) or flood depths are shown. Mandatory flood insurance purchase requirements and floodplain management standards apply. (In unincorporated Lee County, the county has estimated BFEs in these areas.)
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AE
| Areas subject to inundation by the 1 percent annual chance flood event determined by detailed methods. Base Flood Elevations (BFEs) are shown. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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AH
| Areas subject to inundation by 1 percent annual chance shallow flooding (usually areas of ponding) where average depths are between one and three feet. Base Flood Elevations (BFEs) derived from detailed hydraulic analyses are shown in this zone. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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AO
| Areas subject to inundation by 1 percent annual chance shallow flooding (usually sheet flow on sloping terrain) where average depths are between 1and 3 feet. Average flood depths derived from detailed hydraulic analyses are shown in this zone. Mandatory flood insurance purchase requirements and floodplain management standards apply. Some Zone AO areas have been designated in areas with high flood velocities such as alluvial fans and washes. Communities are encouraged to adopt more restrictive requirements for these areas.
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AR
| Areas that result from the decertification of a previously accredited flood protection system that is determined to be in the process of being restored to provide base flood protection. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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A99
| Areas subject to inundation by the 1 percent annual chance flood event, but which will ultimately be protected upon completion of an under-construction Federal flood protection system. These are areas of special flood hazard where enough progress has been made on the construction of a protection system, such as dikes, dams, and levees, to consider it complete for insurance rating purposes. Zone A99 may only be used when the flood protection system has reached specified statutory progress toward completion. No Base Flood Elevations (BFEs) or depths are shown. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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V
| Areas along coasts subject to inundation by the 1 percent annual chance flood event with additional hazards associated with storm-induced waves. Because detailed hydraulic analyses have not been performed, no Base Flood Elevations (BFEs) or flood depths are shown. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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VE, V1-30
| Areas subject to inundation by the 1 percent annual chance flood event with additional hazards due to storm-induced velocity wave action. Base Flood Elevations (BFEs) derived from detailed hydraulic analyses are shown. Mandatory flood insurance purchase requirements and floodplain management standards apply.
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Zones outside the SFHA (floodplain)
Moderate flood hazard areas, labeled Zone B or Zone X (shaded) are also shown on the FIRM but are not considered part of the Special Flood Hazard Area. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2 percent annual chance flood, are labeled Zone C or Zone X (unshaded).
X (Shaded), B
| An area of moderate flood hazard that is determined to be outside the Special Flood Hazard Area between the limits of the base flood and the 0.2 percent annual chance (or 500-year) flood.
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X (Unshaded), C
| An area of minimal flood hazard that is determined to be outside the Special Flood Hazard Area and higher than the elevation of the 0.2 percent annual chance (or 500-year) flood.
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Regulatory Floodways
Within the Special Flood Hazard Area, FEMA has designated Regulatory Floodways along some rivers, creeks or other water channels. FEMA regulates filling and construction in floodways to allow flood waters to be discharged without raising surface water levels beyond a designated height. Inclusion in a regulatory floodway does not specifically impact flood insurance rates, but it does affect construction regulations.
Floodway vs Flowway:
A floodway is the HYPOTHETICAL ground area near a body of water (whether it be a river, creek, canal) - this surrounding ground area near the body of water is where water will overflow to in the event of a flood/overflow of that body of water. That's why building/construction is more restrictive and regulated in floodways as to not increase water levels beyond a certain designated height.
Flow way is any natural or manmade overland path excess surface water will take from one storage area to the next; typically including rivers, creeks, canals, and lower areas connecting flows from wetland to wetland.
All permits issued in the regulatory floodway must be reviewed for their impact on the floodway. Filling and construction may be permitted only in these circumstances:
- FEMA No-Rise (No-Impact) Certification – A licensed professional engineer (PE) may certify that the fill and/or No-Impact Certification Guideconstruction will not cause the floodway to rise.
A narrative format may be used for certain minor projects, especially where the construction site is at or above the base flood elevation or in the shadow of an existing conveyance.
Hydraulics modeling must be submitted for all other projects. Currently for unincorporated Lee County, the HEC-RAS model is used.
Minor project waiver – Lee County may waive the requirement for minor projects, where the impact on the floodway is clearly negligible and the cost of engineering would exceed the cost of the project.
- Parcel owners may also apply directly to FEMA to change the boundaries of the regulatory floodway. Options for Letters of Map Change include:
Letter of Map Amendment (LOMA) – If the parcel is higher than the base flood elevation, FEMA may amend the zone for that parcel and place it in the X Zone.
Letter of Map Revision – A professional engineer may submit certified, updated hydraulics and/or hydrology modeling to show that the parcel should not be included in the regulatory floodway.
Conditional Letter of Map Revision – A professional engineer may submit certified, updated hydraulics and/or hydrology modeling to show that proposed construction can be accomplished to eliminate any rise in the floodway. This often requires construction of drainage areas, culverts or other drainage systems and preserved open space on the site.
Lee County's Guide to No-Rise (No Impact) Certification - For applications to FEMA for letters of Map Revision based on Fill (LOMR-F) in a regulatory floodway, the process will be reviewed under the MT-2 process (not the MT-1 process).