A NUMERICAL STUDY OF SENSITIVITY FOR THE INLAND ROUGHNESS EFFECT IN REDUCING STORM SURGE INUNDATION

Abstract

The most serious inundation damage, with loss of lives and properties, was caused bytyphoon MAEMI in September 2003. After this event, there has been increased interest inaddressing these coastal zone problems. It is therefore desirable to accurately forecast thestorm surge height. This study describes sensitivity for the land surface roughness effect inreducing storm surge inundation to typhoon characteristics. Firstly, the reduction ofinundation area and depth by inland roughness effect is incorporated into the numericalmodel by adopting Manning’s coefficient. Then using a numerical finite-volume coastal oceanmodel (FVCOM), a storm surge was simulated to investigate its inundation characteristics inthe coastal area at Masan, Yeosu and Busan cities on the southern coast of Korea fortyphoon MAEMI. The model grids were extended up through the lowland area by applying theDEM for the minimum 30 m resolution, made by combining airborne-LiDAR survey andbathymetry data. And GIS-based land cover dataset was used for bottom roughnesscharacteristics. Simulated inundation range and depth were compared with the inundationmap made from field measurements after the typhoon event. to accurately forecast thestorm surge height. This study describes sensitivity for the land surface roughness effect inreducing storm surge inundation to typhoon characteristics. Firstly, the reduction ofinundation area and depth by inland roughness effect is incorporated into the numericalmodel by adopting Manning’s coefficient. Then using a numerical finite-volume coastal oceanmodel (FVCOM), a storm surge was simulated to investigate its inundation characteristics inthe coastal area at Masan, Yeosu and Busan cities on the southern coast of Korea fortyphoon MAEMI. The model grids were extended up through the lowland area by applying theDEM for the minimum 30 m resolution, made by combining airborne-LiDAR survey andbathymetry data. And GIS-based land cover dataset was used for bottom roughnesscharacteristics. Simulated inundation range and depth were compared with the inundationmap made from field measurements after the typhoon event.