Dewberry, a privately held professional services firm, has been selected by the U.S. Army Corps of Engineers, Savannah District, to assist in the second phase of updating the Georgia Hurricane Evacuation Study (HES), originally completed by the firm in 2013. Under the latest task order, Dewberry will provide a new Shelter, Behavioral, and Transportation Analysis for the Georgia HES.
Funded by the Federal Emergency Management Agency (FEMA), the project is being coordinated with the Georgia Emergency Management Agency and FEMA Region IV. Dewberry recently completed the first phase of the update, which encompassed a Hazard and Vulnerability Analysis that examined population shifts; changes in the risk of hazards such as storm surge, wind, and inland flooding; and the vulnerability of critical infrastructure.
The second phase of the update will examine how residents respond to evacuation orders and what information sources are used most frequently, and estimate the number of evacuees who will seek public shelter, to determine the amount of shelter space required as well as the number of spaces currently available. The potential for special needs and evacuation assistance will also be reviewed. This update will also determine evacuation clearance times—the time necessary for a vulnerable population to evacuate once an order is issued under various scenarios. Because the original study was conducted nearly a decade ago, the study will also cover a review of transportation routes, including potential choke points and the addition of any major roads.
“We’ve completed a comprehensive analysis of the hazard risks and potential vulnerabilities within communities based on storm surge and wind data from the National Hurricane Center (NHC),” says Kevin Slover, senior coastal scientist for Dewberry. The NHC uses its Sea, Lake and Overland Surges from Hurricanes (SLOSH) Model to predict the surge inundation extent and water depths from various categories of hurricanes.
“This next phase will explore the behavioral pattern of the population—when they might leave under an evacuation order, where they might go, what resources are available, and what impediments might occur. This information will help emergency planners as they work to develop evacuation and mitigation plans to protect lives and keep communities safe,” says William Massey, senior project manager and hurricane subject matter expert for Dewberry.
The study focuses on 11 counties within Georgia’s Lower Coastal Plain, a region characterized by abundant marshland, wetlands, and swamps as well as the state’s coastal barrier islands. Due to the shape of the coastline and shallow water depths along the coast, Georgia has one of the highest potentials for storm surge heights on the East Coast. The NHC storm surge models have indicated that hurricane storm tides could reach over 30 feet in height and travel inland for several miles.
Primary users for the updated data include the coastal counties of Chatham, Bryan, Liberty, McIntosh, Glynn, and Camden. The project data will also support emergency planning in the inland counties of Effingham, Long, Brantley, Charlton, and Wayne. Dewberry’s services in the first phase of the update included development of a user-friendly tool called GeoPDF that allows users to access technical data without having to use GIS.