Effect of Storm Size on Predicted Hurricane Storm Surge in Southeast Louisiana

An investigation into the effect of hurricane storm size on resulting storm surge in southeast Louisiana is performed. Two hypothetical storms differing in size and intensity are investigated using the ADCIRC storm surge model. Three tracks are studied. The tracks chosen represent critical tracks to southeast Louisiana based on historical data. Simulations are begun 30 hours before landfall with wind ramping during the first 6 hours so that full force winds begin 24 hours prior to landfall. Prior to landfall the hurricane is assumed to be steady state. After landfall, a landfilling model is used to simulate weakening of the hurricane due to interaction with land. Before performing the hurricane simulations, the ADCIRC model is run for a two day simulation with inflow boundary conditions on the Atchafalaya and Mississippi rivers to provide correct initial water surface elevations for the storm surge simulations. Tidal dynamics are not considered. Contours of maximimum water surface elevation and elevation histories at selected locations in the metropolitan New Orleans area are presented for each simulation. The results of the study clearly indicate that storm size can affect coastal storm surge regardless of the category of the hurricane as expressed by the Saffir-Simpson scale.