Assessment of Coastal Inundation due to Storm Surge under Future Sea-Level Rise Conditions

Abstract

Kim, Y.H., 2020. Assessment of coastal inundation due to storm surge under future sea-level rise condition. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 845–849. Coconut Creek (Florida), ISSN 0749-0208.Coastal communities, transportation systems, and energy infrastructures will be at increasing risk of impact from the extreme events like storm surge. Coastal areas are at risk for worse inundation in the near future due to coupled effects of sea-level rise and surge under the future global climate change scenarios. In order to assess the impact of coastal inundation due to the combined effect of sea-level rise and tropical storms, Sea, Lake and Overland Surge from Hurricanes (SLOSH) model was implemented to coastal areas of Korea. SLOSH calculates water level from depth-integrated, quasi-linear, shallow-water equations. In this study, a new developed high-resolution hyperbolic mesh grid was applied to the Korean peninsula. The minimum and maximum grid size is 321 m in coastal regions and ∼18 km in offshore areas, respectively. A total of 60 representative potential storm tracks were developed based on preselected four historic storm tracks in the study area. Each storm tracks were assumed to be 2 different strength, implying each 50 and 100-yr return frequency level. Five different sea-level rise scenario were applied on the basis of the recent IPCC report: 0, 34.1, 65.0, 83.8, and 98.0 cm above the present sea level. Thus, a total of 600 scenarios (= 5 sea levels X 2 strength X 60 storm tracks) were simulated, and Maximum Envelop Of Water (MEOW) and Maximum Of Maximum (MOM) were calculated for each water level case. The results show that the rise of sea level induces higher storm surge and the increasing trend is not linear. For instance, the case with 98 cm sea-level rise above the current sea level show about 1.5-2.5 m increase of storm surge. Also, the results of storm surge (i.e., MOM) were applied to local topography data, which estimate inundation depth for each cell. As expected, the case of present sea level depicts lowest inundation and it increase with the range of sea level rise. Also, the area of inundation is smallest in the case of present sea level, and more sea level rise results in larger area of inundation.