on the muddy coast, western Bohai Bay, China

Based on collation of the flooding levels of the 11 storm surges since 1895 in the west coast of Bohai Bay, this paper verified and redefined the flooding levels with a probability of exceedance of 1 in 50, 100, 200... to 10000 years. Contributions of both wind set-up and wave to high water levels are quantitatively estimated as 50cm, respectively. Moreover, the various factors, including sealevel rise (starting from 2009 for every 10-yr-interval in 2009-2100: 3-31cm), land subsidence coincident with reclamation, net increase of flooding level stimulated by the sealevel rise (2020-2050: 7.5-30cm) and the mouth-channel effect (10cm) were discussed. Based on these parameters, the extreme flooding levels under probability of exceedance of 1 in 50 to 10000 years, respectively, were predicted until 2050 for every 10-yr-interval, and the leveling-correction affected by the subsidence was also discussed. We indicate the height of the existing seadike is capable to defense the storm surges of 1 in 50 to 100 years. However, based on the comprehensive factors discussed in this paper, it is suggested that the seadike should be reached to +4.8m in 2020 and +5.1m in 2030, respectively (both the State 85 Datum).