Trend prediction of extreme high water levels in the coastal area of Tianjin, China in the middle of the 21st century

According to the available statistic data, the 1-in-50-year extreme water level (ewl) caused by storm tides was +4.092 m in the coastal area of Tianjin. The land subsidence rate is ~15 mm/a after the land subsidence is controlled. Now the elevation of the top of the coastal levee is +4.332 m above sea level in general. Following the 0.2m increasing of the projected sea-level-rise, adding extra 0.5m in Bengal Bay, London and Hamburger etc. in 2050 for the extreme high water, we forecast the local ewl will be increased to +4.792m (4.092m+0.2m+0.5m) in the area in 2050, while the top of levee will be sunk to +3.687m at that time (with the starting year of 2007). As a result, the predicted ewl will be 1.105 m higher than the sunk tops of levees in 2050. This will increase the risk of the flooding of storm tide water and occurrence of a disaster. This risk will be even graver in consideration of the influences of a number of uncertain factors such as wave superposition, estuarine effect and extreme sea level rise.