Abstract

Coastal plains in southeast Florida are prone to flooding by storm surges and extreme rainfalls. In the example of southeast Florida, coastal flood studies are based on well-defined evacuation zones that are mapped according to hurricane intensity. The areal extent of flooding, due to high-rainfall storm events, on developed wetlands and “flood-proofed” coastal plains is difficult to assess using conventional techniques because the landscape is being rapidly modified by urban development. New techniques deployed in the emergency management preparedness process include spatiotemporal analysis of satellite imagery in conjunction with geographic, land, and marine information systems. Land uses within flood hazard zones are classified from satellite images in an effort to quantify the impacts of storm surges for successively higher flood levels associated with hurricane Categories 1, 3, and 5 evacuation scenarios. The geomatics involved shows that ~10% of the total flood zone is in urban/residential land use but accounts for most of the damage to personal property and infrastructure. Potential flood zones on interior coastal plains were mapped from GIS soil coverages by identifying locations of hydric soils, poor drainage conditions, surface water hydroperiods, and associated hydrogeomorphic features. These advanced procedures helped establish a new protocol for coastal flood-hazard mapping in Broward County, Florida.