Enhancing the Federal Emergency Management Agency's Toolbox for Identifying and Mapping Coastal Flood Hazards

Abstract

The Federal Emergency Management Agency (FEMA) is responsible for preparing Federal Insurance Rate Maps (FIRMs) that delineate flood hazard zones and Base (1-percent-annual-chance) Flood Elevations in coastal areas of the United States. Recently FEMA has invested in a major effort to modernize their coastal guidelines and specifications. New or updated guidelines have been developed for analyses of flooding from the Pacific Ocean (FEMA, November 2004), Atlantic Ocean (FEMA, February 2007), Gulf of Mexico (FEMA, February 2007), and updated guidance for the Great Lakes is currently being developed. In addition to these wholesale updates, additional guidance has been developed for a variety of specific topics such as identifying and mapping of areas subject to breaking waves greater than 1.5 feet as an informational layer on FIRMs. This specific guidance, discussed in more detail below, along with a modernized Appendix D, facilitates accurate, detailed identification of coastal flood risks and provides one piece of FEMA's solution to coastal flood hazards.