Alternative Text Description for Base Floodline Elevation

TABLE OF CONTENTS

MAP OVERVIEW

This map displays Base Flood Elevation lines across Florida, representing the water surface elevation of the 1-percent-annual-chance flood event (commonly known as the 100-year flood). The Base Floodline Elevation layer shows where flood elevations have been calculated and mapped as part of FEMA's flood insurance mapping program. These lines indicate rounded whole-foot water surface elevations within Special Flood Hazard Areas and are used to determine flood insurance requirements and construction standards.

GEOGRAPHIC CONTEXT

The map covers the entire state of Florida, from the panhandle region in the northwest extending south to Miami and the Florida Keys. Major cities labeled on the map include Montgomery and Columbus to the north, Dothan and Albany in the central northern area, Valdosta and Jacksonville along the eastern corridor, Orlando and Melbourne in the central region, Tampa and Petersburg on the west coast, Cape Coral in the southwest, and Miami in the southeast. The map shows Florida bordered by the Gulf of America to the west and south, and the Atlantic Ocean to the east. Savannah, Georgia appears in the northeast corner, and coastal features are visible throughout the peninsula.

KEY INSIGHTS

Base Flood Elevation lines are extensively distributed throughout Florida's coastal regions, with the highest concentration occurring along the entire Gulf of America coastline, the Atlantic coast, and around major inland water bodies. The density of BFE lines follows Florida's waterways and coastlines, with particularly prominent coverage in the Tampa Bay area, the southwestern coastal region near Cape Coral, the Jacksonville metropolitan area, and along Florida's panhandle. The central interior portions of Florida show fewer BFE lines, indicating less mapped riverine flood hazard in these areas. The distribution pattern reveals that flood elevation mapping is most intensive where coastal and major riverine flood risks intersect with developed areas.

VISUAL ELEMENTS

Base Floodline Elevation

This layer represents lines that mark specific flood elevation values within flood hazard areas across Florida.

Base Flood Elevation Lines (black irregular lines)

Appearance:

Black lines appearing in irregular, branching patterns that follow waterways and coastlines. The lines vary in density and form complex networks in coastal areas.

Distribution:

BFE lines are distributed throughout Florida with primary concentrations along the Gulf of America coastline from the panhandle through the southwest coast, along the Atlantic coast from Jacksonville through Miami, and around major inland water features. Lines extend inland from coastal areas, following river valleys and estuarine systems.

Notable locations:

Dense concentrations appear in the Tampa-St. Petersburg metropolitan area, the Cape Coral-Fort Myers region, the Jacksonville area, the Florida panhandle coastal zone, and throughout the southeastern coast near Miami. Significant inland penetrations follow major river systems including those near Orlando, around Lake Okeechobee (central-south Florida), and along the St. Johns River corridor.

Spatial patterns:

The lines form dendritic (tree-like) branching patterns that follow natural drainage systems and coastal embayments. Coastal areas show continuous linear patterns paralleling shorelines, while riverine areas display branching networks that extend inland along stream corridors. The spacing between lines varies based on topography and flood hazard complexity, with denser line patterns in areas with more gradual elevation changes or complex coastal geomorphology.

Overlapping Patterns

Areas with the highest density of overlapping BFE lines occur where multiple waterways converge, in extensive coastal marshland areas, and around major estuaries. The southwestern Florida coast shows particularly complex overlapping patterns where numerous tidal creeks and coastal waterways create intricate networks of flood elevation lines.

SYMBOL GUIDE

ADDITIONAL INFORMATION

Base Flood Elevation lines are depicted on published Flood Insurance Rate Maps as wavy lines but are represented in the digital spatial data as primarily straight lines that may bend to follow natural features. These lines typically appear in areas designated as AE zones (riverine floodplains with base flood elevations determined). The BFE values shown by these lines are used to establish flood insurance premiums and determine required elevation for new construction in flood hazard areas. Not all flood hazard areas have BFE lines; some zones may be mapped without detailed elevation data. The visible concentration of BFE lines reflects both actual flood risk and the availability of detailed flood studies for particular areas of Florida.

DATA CONTEXT

Data Source:

The data is derived from FEMA's Digital Flood Insurance Rate Map (DFIRM) Database, which depicts flood risk information used to develop flood hazard classifications. The database is compiled from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of these studies, and new mapping data where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). Data source layer name: DFIRM_BFE_DEC24.

Definition Query:

No definition query or filter criteria was provided for this map view.

Scale Information:

The map is displayed at a statewide scale showing the entire state of Florida. At this scale, individual BFE line details and specific elevation values are not readable, but the overall distribution pattern and geographic coverage of flood elevation mapping is visible. Detailed elevation values and specific BFE information would be visible at larger scales (zoomed in views) of local areas.

Coordinate System:

NAD_1983_HARN_Florida_GDL_Albers (WKID 3087)

Time Period of Content:

The data is dated December 2024 (DEC24), indicating this represents the most current FEMA flood mapping data available as of that date.

Limitations:

BFE lines are shown only where detailed flood studies have been completed and base flood elevations have been calculated. Areas without BFE lines may still be subject to flooding but lack detailed elevation determinations. The DFIRM database is updated periodically as new flood studies are completed, so coverage and detail vary across the state based on study age and availability. The map shows the presence of BFE lines but does not display the specific elevation values, which would require viewing the data at a larger scale or consulting the attribute data.

Map Coverage:

The map extent covers the entire state of Florida and portions of neighboring states (Georgia and Alabama) for geographic context. The thematic data (Base Flood Elevation lines) is limited to Florida's boundaries and coastal waters.

The alternative text description of this map was AI-generated and may contain inaccuracies.