Alternative Text Description for DFIRM 500 Year Floodplain

TABLE OF CONTENTS

MAP OVERVIEW

This map displays areas within the 500-year floodplain across the state of Florida. The 500-year floodplain represents areas with a 0.2% annual chance of flooding, indicating moderate flood risk zones. The map shows the extensive distribution of flood-prone areas throughout Florida, derived from Digital Flood Insurance Rate Map (DFIRM) data and presented as a raster dataset with 10-meter resolution.

GEOGRAPHIC CONTEXT

The map covers the entire state of Florida, extending from the panhandle region in the northwest to the Florida Keys in the south. Major cities labeled on the map include Pensacola, Jacksonville, Gainesville, Orlando, Tampa, St. Petersburg, Cape Coral, and Miami. The map also shows portions of neighboring states including Georgia to the north (with Albany and Dothan visible) and Alabama to the northwest. Florida's distinctive peninsula shape is clearly outlined, bordered by the Atlantic Ocean to the east and the Gulf of America to the west. The map extends slightly beyond Florida's borders to provide geographic context.

KEY INSIGHTS

The 500-year floodplain areas are extensively distributed throughout Florida, affecting both coastal and interior regions. Significant concentrations of floodplain areas appear along the entire coastline, particularly prominent along the Gulf of America coast and in South Florida around Miami. Large interior floodplain zones are visible in central Florida, likely corresponding to major river systems and lake regions. The panhandle region shows substantial floodplain coverage, especially along the Gulf coast. Notable is the extensive floodplain coverage in the Everglades region of South Florida and throughout the lower peninsula. Interior central Florida shows significant floodplain areas that appear to follow major drainage basins and waterways. The Florida Keys show complete coverage as floodplain areas.

VISUAL ELEMENTS

DFIRM 500 Year Floodplain Layer

This layer represents areas classified as within the 500-year floodplain based on Digital Flood Insurance Rate Map data. The layer displays areas with a 0.2% annual chance of flooding.

500 Year Floodplain Areas (cyan/turquoise shading)

Appearance:

Depicted in cyan or turquoise shading against a gray background representing non-floodplain areas.

Distribution:

Floodplain areas are distributed throughout Florida with particularly dense coverage along coastal zones, in South Florida, across the panhandle, and in central Florida's interior regions.

Notable locations:

Spatial patterns:

The floodplain areas form linear patterns along coastlines and appear to follow river corridors and drainage systems in interior regions. There is a clear relationship between floodplain distribution and low-elevation coastal zones. Interior floodplain areas show branching patterns consistent with riverine and watershed systems. The density of floodplain coverage increases significantly in South Florida, where it becomes nearly continuous across the landscape.

Overlapping Patterns

Floodplain areas intersect with or are adjacent to major population centers including Tampa, St. Petersburg, Cape Coral, Miami, Jacksonville, and Pensacola, indicating significant flood risk exposure for developed areas. Coastal floodplain zones merge with interior riverine floodplain systems, creating continuous flood-prone corridors.

SYMBOL GUIDE

ADDITIONAL INFORMATION

The 500-year floodplain designation indicates areas of moderate flood risk where there is a 0.2% probability of flooding in any given year, or approximately a 10% chance over a 50-year period. This designation is used for regulatory purposes and flood insurance considerations. The map shows only the 500-year floodplain layer and does not display the more restrictive 100-year floodplain boundaries, which would represent higher-risk flood zones. This raster dataset provides statewide coverage at a 10-meter cell resolution, allowing for detailed identification of flood-prone areas. Base map features such as roads and political boundaries are shown for reference but are not part of the thematic floodplain data layer.

DATA CONTEXT

Data Source:

The data is derived from Digital Flood Insurance Rate Maps (DFIRM), which are created through detailed hydrologic and hydraulic analysis. The original source is the DFIRM_FLDHAZ vector layer, which has been converted to a raster format with a 10-meter cell size. The data source layer name is DFIRM_500_DEC24.

Definition Query:

This layer represents a specific subset of DFIRM data showing only areas within or outside the 500-year floodplain designation, filtering out other flood hazard classifications that may exist in the complete DFIRM dataset.

Scale Information:

The map is displayed at a statewide scale showing all of Florida. The 10-meter cell size of the raster data provides detailed resolution appropriate for state and regional-level flood risk assessment.

Coordinate System:

NAD_1983_HARN_Florida_GDL_Albers (WKID 3087)

Time Period of Content:

The data is dated December 2024 (DEC24), as indicated in the data source layer name.

Limitations:

As a raster dataset, the map represents generalized flood zones and may not capture all site-specific variations in flood risk. The 10-meter resolution provides good detail but may not be sufficient for parcel-level or site-specific flood determinations. Areas shown as outside the 500-year floodplain are not necessarily flood-free, as flooding can occur outside mapped zones. Users should consult official DFIRM maps and local floodplain administrators for regulatory determinations.

Map Coverage:

The map covers the entire state of Florida and includes portions of adjacent states (Georgia and Alabama) for geographic context. The Florida Keys and all coastal islands are included in the map extent.

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