Re-assessment of future sea level and its potential impacts in Wan Chai

Abstract

This study analyzed what extent of flooding can be caused under marine flooding and blockage of drainage system in Wan Chai. Using the 50 years tide gauge records from North Point (1964 – 1985) and Quarry Bay (1986 – 2013) Tide Gauge Stations obtained from Hong Kong Observatory so as to have sea level projection until the end of 21st century. After the calculation, we got the sea level rise at a rate equals to 2.2mm per year and 2.3mm per year under mean sea level and highest high water level respectively. Based on the projection trend, we produce flood map in Wan Chai in 2013 and 2099 using ArGIS system in order to have comparison under different scenarios. Moreover, under extreme cases that can cause flooding happened in both 2013 and 2099 in Wan Chai. Apart from marine flooding, due to sea level rise under the case of mean sea level and highest high water level, the discharge rate of drainage system in Wan Chai will be reduced and caused flooding happened in some areas of Wan Chai. Therefore, some mitigation should be provided by Drainage Services Department so as to relieve the flooding problems.