Natural Disaster Risk Assessment

Natural disaster risk research is drawing extensive attention in current society and researching field, while its central topic of natural disaster risk assessment is an important foundation and way for establishing disaster-prevention-and-mitigation policies and measures. After summarizing the developments and theories of the natural disaster risk assessment, the flood disaster risk assessment is experimentally studied based on the housing and farmland of New Pudong district of Shanghai, and the results obtained are as follows:(1)Summarizing the developments of natural disaster risk assessment, it is concluded that its norm system is already pretty mature at home and abroad. However, there are still some limitations: the middle and small scale quantitative natural disaster risk assessment is not so general in China as abroad, and the hazard-affected bodies selected are very limited; all the natural disaster risk assessment studies are limited to simple addition of single-hazards due to lack of theories and methods. Thus the disaster risk assessment based on the coupled effect of multiple disasters and multiple hazard-affected bodies will become the future topic;(2)The flood disaster risk assessment of the housing of New Pudong district of Shanghai utilizes the dynamic assessment method based on six kinds of flood with different recurrence intervals. Using the remote sensing and GIS tools and the flood disaster hazard analysis, vulnerability analysis and exposure analysis methods, the study is performed on the following aspects: first, the inundation depth and area is simulated for the studying area under six kinds of flood with different recurrence intervals and maximum daily rainfall based on the flood disaster hazard analysis; Second, the correlation between the inundation depth and the damage rate of housing and indoor property for sheds, crude shacks and houses on three kinds of residential land is figured out through exposure analysis; Third, exposure analysis is conducted on inundated housing and indoor property; finally, based on the analysis above, the disaster damage situations are obtained for the sixth kinds of floods with different recurrence intervals and the average flood damage quantity is figured out for the studying area using the correlation between the transcendental probability (recurrence interval) and damage rate. Results obtained are:â‘ the annual average damage is 58000 yuan according to the transcendental probability correlations for the flood disaster of the central region housing of the New Pudong district of Shanghai;â‘¡the maximum inundation depth is 0.6m according to simulations for the six kinds of flood with different recurrence intervals; the investment for disaster-prevention-and-mitigation is practical if money involved smaller than58000yuan. Besides, people will be safe for all the six kinds of floods with different recurrence intervals.(3) Rainstorm flood risk assessment of agriculture land-use in Pudong Xinqu District is to construct the hazard risk assessment system by analyzing hazards, vulnerability, exposure three aspects. First, simulating the relationship about inundated depth and inundated time in two kind of rainstorm scene with analyzing the rainstorm flood. Then, constructs the relationship of the crop vulnerability curve, inundated depth and inundated time by analyzing the crop types, growing manners and time, habitat circumstance. The last step is that to find out the agriculture land which is exposed to rainstorm flood. Base on the above three steps, computing each kinds of crop's rainstorm flood risk which the crop confront by using different risk assessing models.The result of the study indicates that:â‘ The rainstorm risk which the wheat confronts is 62.1 Yuan per hectare with precipitation of 100mm. Base on the tab. 4-2, know that the wheat will not been influence by this kind of rainstorm basically under precipitation of 232.9mm because it will not appear from May to September when the wheat is growing up;â‘¡The rainstorm risk which the vegetable confronts is 1394.6 Yuan per hectare with precipitation of 100mm. Because of lacking the distribution data, the most possible loss of vegetable is estimated at 120 Yuan per hectare under precipitation of 232.9mm. This means that the possible loss per hectare about agriculture land is 11996.4 Yuan with the probability of 0.01.