| Storm surge generated by tropical cyclone is the most hazardous natural phenomena in eastern China, and causes great losses and casualties in the coastland areas. As for seaports in coastal cities, they are located in the most vulnerable areas to storm surge disaster, and thus confronted with more impacts of climate change, extreme storm surge events, and increased flooding. Moreover, they play a critical role in the global shipping and the economic development. Therefore, assessing the potential hazard risk of seaports is of theoretical and practical significance.This dissertation was financially supported by the National Natural Science Foundation of China (No.40730526), Shanghai Science and Technology Venus Project (No.09QA1401800), and the Key Scientific Research Projects of ECNU. In the present study, based on the scenario-simulation theory, Yang Shan Deep-water Port was selected as the study object to analyze the hazard of flooding due to storm surge from the perspective of "identify the hazard risk-analyze the evolution of the hazard-formative environment-simulate the hazard in different scenarios-make the hazard zoning and discuss the countermeasures" by using the tools of ArcGIS, MIKE21, and MATLAB. In the present study, the following work was conducted, and several main conclusions were drawn as follows.1. Identified the storm surge hazard in the study area, i.e., analyzed the characteristics of typhoons that resulting in storm surge disaster.(1) The spatial tracks of typhoon should be within the region that will confront the attack of typhoon in24hours, and in the north of East China Sea area. The typhoon will make landfall on the north of the27°N, or go to the north direction through the sea. There are3kinds of tracks that might impact on the study area, i.e., Type I northward landing typhoon, Type II westward landing typhoon, Type III northward typhoon through the sea.(2) The maximum wind speed should be upon Force7, and the center pressure should be lower than1000hpa.(3) The typhoon should be formed in August or September and during the strong ebb-tide time. The wind duration of force over8on Beaufort scale will have effort on the tidal level of storm surge.2. Analyzed the evolution of the hazard-formative environment of storm surge hazard in the study area, and built the future underwater and land topography.(1) The seabed topography in the natural state was in a slight change state. However, the annual erosion/siltation rates were obviously higher and the underwater topography changed a lot during the engineering construction period.(2) The land use type and land boundary of the study area were changed significantly during the construction of Yang Shan Port. The land boundary was stable in2008when the north side port engineering was finished completely. It, however, will probably change again after2020. Therefore, this paper just predicted the topography of Yangshan Port in the next few years to ensure the reliability of the results.(3) Predicted the topography condition in2015.3. The storm surge hazard was simulated under different typhoon wind field scenarios and topography scenarios by employing MIKE21hydraulic model.(1) Type III is the most dangerous typhoon track.(2) The inundated area and depth of the tidal level of storm surge both raise with the increasing of the typhoon intensity.(3) The predicted topography of2015would strengthen the storm surge hazard. If the hazard-formative environment could change as predicted, the study area will encounter stronger storm surge hazard.4. Conducted the hazard risk zoning for extreme scenarios (the500year return period typhoon intensity):(1) the islands and most part of Donghai Bridge will be the safe region; and the green area mainly be the high/serious hazard risk region.(2) In the2008topography scenario, the north part of the Kezhushan as well as the road, and the west part of the residential area were low hazard risk region; the south part of Kezhushan, the west part of the Dachengzishan as well as the road, and the middle part of the residential area were the middle hazard risk region; the east part of Dachengzishan as well as the road, the northeast and the east of the residential area were the high/serious hazard risk region.(3) In the2015topography scenario, the main part of Yangshan Port, the south part of Bodaoju, and the middle-west of the residential area will be the low hazard risk region; Kezhushan will be the high hazard risk region; both the east and west side of the Dachengzishan as well as the road, the northwest and east part of the residential area will be the serious hazard risk region. 5. Discussed the countermeasures for the hazard risk analysis results, e.g., building the emergency shelters in the hilly islands; guiding the people (in the residential area) and the equipment and materials (on the roads) that are over low hazard risk to transfer, guiding the equipment and materials in the port that are over middle hazard risk to transfer; reinforcing the flood prevention capability of coastlines that are over low hazard risk; strengthening the levees on the north, west and east sides of the Dayangshan Island. |
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