ABSTRACT

Suh, S. and Kim, H., 2020. Extreme surge heights incorporating long-term tidal variation and sea-level rise. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1542–1546. Coconut Creek (Florida), ISSN 0749-0208.

Global warming is a primary factor for acceleration of sea-level rise (SLR). Most previous studies have dealt only with mean SLR; however, in terms of storm surge inundation, not only the mean SLR, but also the summer seasonal SLR, which is locally almost 20 cm higher on the west coast of Korea because of thermal expansion and riverine runoff, must be considered. In addition, the nodal effects of the 18.6-year tidal variation should be considered for long-term (through 2100) surge hazard analyses. Tidal analyses were conducted at the Incheon station, which is located in the middle of the west coast of Korea, using records from 1960 to 2018. Peak M2 amplitudes varying from 2.96 to 3.02 m were obtained in 1979, 1997, and 2015, while the lowest value of 2.76 m was obtained in 1968, 1985 and 2006. The analysis predicted that the resulting tidal range, would show peak values this century in 2025, 2043, 2062, and 2099. To determine the extreme surge height (SH), this study generated synthetic storms. These storms were generated with a Perl script by adjusting typhoon parameters based data reported in the literature. Upon considering the nodal factor, the resulting SH in 100 years would vary from 1.18 to the 1.31 m mark on the west coast, while it would vary from 0.68 m to 0.71 m on the south coast of Korea. These extreme SHs are potentially hazardous to existing coastal infrastructure such as levees and dikes. This study is relevant to the mitigation of coastal hazards, incorporating not only extreme SH but also wave-induced overtopping hazards on artificial coasts where anthropogenic impacts were made without considering future sea-level changes.

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