CALCULATION AND COMPARISON OF THE FLOOD RISK POTENTIAL DUE TO RAINFALL EVENTS, HIGH TIDES, SEA LEVEL RISE, STORM SURGE AND THE COMBINATION OF ALL THE CASES ON THE EASTERN COAST OF FLORIDA

Coastal basins are particularly vulnerable to flood under multivariable conditions, such as heavy precipitation, high sea levels, tropical storm surge and rainstorms. These conditions should be considered to assess and manage flood risk better. In this research, a means to develop a watershed level screening tool to identify areas with potential for flooding due to high tides, rainfall events, sea level rise and combinations of all the cases was developed and compared to FEMA maps. The goal of the screening tool is part of a larger effort with respect to watersheds funded by the Florida Division of Emergency Management to enable local communities to reduce flood insurance costs through mitigation and resiliency efforts by means of risk assessment was undertaken. For this purpose, readily available data on topography, ground, and surface water elevations, tidal data for coastal communities, soils, and rainfall data were collected from the South Florida water management district, USGS, and NOAA. Firstly, using elevation data, soil data, and the Spatial Analyst tool, Arc-Hydro tools of ArcGIS, the drainage network, and soil storage capacity were determined. These results and rainfall data acted as inputs for Cascade to calculate the headwater height for all the cases for the selected basins. Using these headwater heights, several different probabilities of inundation were determined. This study will help manage and mitigate vulnerable areas and act as a tool to permit local agencies to develop means to address high-risk properties.