Risk Assessment And Scenario Simulation Of Storm Surge In Shanghai Coastal Areas

Natural disaster is the hotspot question in international society and academe. Coastal cities are important areas and strategic focus of people convergency, national economy and society development. Shanghai is the economic hub of China and the leading linkage of East-West, North-South. However, storm surge disasters happen easily and frequently in the region, so economic loss is extremely serious. This dissertation will provide bases of theory and scientific tools for storm surge disaster risk management model, emergency plan and sustainable development model.This dissertation was financially supported by the National Natural Science Foundation of China (No.40730526, No.40571006) and Shanghai Science and Technology Venus Project (No.09QA1401800). Based on the analysis of Shanghai storm surge and its formation mechanism, establish the storm surge disaster hydrostatic model on ArcGIS Platform. And based on Mike 21 hydrodynamic model, using numerical and spatial geographic analysis methods, construct storm surge dynamic simulation model. Contrast with hydrostatic model, hydrodynamic model is more reliable and authentic. Therefore, based on dynamic simulation results, from the point of risk, vulnerability and exposure, analysis the risk degrees of different frequencies, and build storm surge disaster risk zoning map, establish storm surge research methodology suitabling for Shanghai.Several main conclusions are shown as follows:1. Constructed Shanghai Urban storm surge disaster system, tidal wave disaster risk systems and disaster risk assessment model. Urban storm surge disaster risk systems composed by the pregnant tidal disaster environment, inducing factors and inheriting body. Tide disaster risk analysis and assessment system include risk identification, risk assessment and risk management. Risk analyses mainly include risk analysis of inducing factors, vulnerability analysis and exposure analysis of inheriting body.2. Using scenario analysis to the risk modeling. Different from the index system, we used a variety of spatial and temporal scenarios (time scale, spatial scale, frequency-return period), the natural scenarios (typhoons, storm surges, land subsidence, sea level rise), man-made scenarios (socio-economic, population distribution) to representating the Historical Storm Surge and simulating future tide disaster. Using ArcGIS to simulate static simulation and using Mike21 to simulate dynamic simulation. Comparison of known, Mike21 dynamic simulation is more authenticity, intuitive.3. Shanghai storm surge disasters are result of weather, terrain, sea-level factors. And has the following characteristics:the annual maximum sustained higher, frequency of each month uneven, the frequencies of storm surges increase, storm surge disaster severe. Using ArcGIS to simulate the static simulation of storm surge disasters in coastal region of Shanghai, we can see that in the dam damage scenarios, whether in the return period of 100 years or in the return period of 1000 years, almost all of the study area affected by the storm surge; in the case of a dam, even taking into account land subsidence factor, in the return period of 100 years and in 1000 years, a long period of time the three coastal areas of Shanghai are not serious.4. In the return period of 100 years, the maximum affected area is 1041.45km2, the proportion of 58.30%of the stucy area, mainly locating in pudong District, south Nanhui District and east Fengxian District. The deepest flooded depth is 1.50m, locating in the beach of southeast coastal areas of Fengxian District where adjacent Nanhui District. In the return period of 1000 years, the maximum affected area is 1384.97km2, the proportion of 72.99%of the stucy area, covering almost all areas of the study area, except northwest Fengxian District.The deepest flooded depth is 2.7m, locating in the coastal areas of Gulu town and Gonglu town.5. Assessing exposure of each land use in the two hours scenarios. Whether in the return period of 100 years or in the return period of 1000 years, residential land and agricultural land in the submerged area changed greatly. The living areas in the return period of 1000 years is 3.75 times of that in the return period of 100 years, and agricultural land area in the return period of 100 years is 6.15 times of that in the return period of 1000 years. The other case of land uses in the storm surge disaster is almost the same.6. According to the Shanghai historical disaster information to determine relationship of the loss rate and water depth, propose disaster loss of different property types. Land use submerged depth superimposed on the corresponding vulnerability to obtain vulnerability of different land uses in the entire study area, namely, the loss rate of disaster. in the return period of 100 years, loss rate of tidal disaster mainly focus on 10%～20%, the largest influx of losses is 50%, corresponding to submergence depth of 1.0m～1.5m in agricultural land. In the return period of 1000 years, loss rate of tidal disaster mainly focus on 10%～20% and 20%～30%, the largest influx of losses is 100%, corresponding to submergence depth of above 2m in agricultural land.7. In the return period of 100 years, the tidal flood disaster loss values in the three coastal areas of Shanghai (Pudong, Nanhui, Fengxian) 505.8685 million RMB. In the return period of 1000 years, the tidal flood disaster loss values 801.9613 million RMB. Tidal flood disaster losses in different return periods are in the order of: Industrial warehouse losses> public facilities losses> transportation land losses> agricultural land loss> green space losses> residential land losses> water space losses.8. Take the Pudong International Airport as the research object, in the return period of 100 years, the maximum affected area is 11.96km2, the proportion of 29.90% of the total area of the Pudong Airport, the deepest flooded depth is 0.59m. In the return period of 1000 years, the maximum affected area is 28.21km2; the proportion of 70.51% of the total area of the Pudong Airport, the deepest flooded depth is 0.62m. Whether in the return period of 100 years or in the return period of 1000 years, the submergence region are most concentrated in the 0m～0.5m range, the proportion of 98.50% and 94.94% of the submergence region.Taking Pudong International Airport economic data in 2009 as the baseline, the economic loss caused by the storm surge in the return period of 100 years was about 5.023 million RMB in all; 99,000 passengers and 8,765,000 tons freight are suspended. In the return period of 1000 years, the economic loss was about 12.014 million RMB in all; 118,800 million passengers and 1,051,800tons freight are suspended.