| Heavy rainstorm and flood have become one of the main natural disasters threatening the public safety of cities,especially for the cities along the river and adjacent to the sea and the low-lying areas,the phenomenon of "city watching the sea" has become common.Traditional urban disaster prevention and mitigation systems are no longer sufficient to deal with largescale and long-lasting flood disasters.Therefore,targeted urban flood disaster resilience evaluation research has become a top priority.Building a more resilient urban system is not only more secure for residents' lives and property,but also has an important significance important for sustainable urban development.Based on the above background,this thesis constructs an evaluation system of urban resilience for flooding with Chongqing as the study area.Combined with different dimensions of urban indicators,the evaluation results are analyzed and the following main conclusions are drawn.(1)Based on optical remote sensing and SAR remote sensing data,the variation of flood range in the study area was calculated.The results show that eight of the nine major districts in Chongqing have recovered more than 50%.Yubei District was the largest affected area on the day of the flood,but its recovery speed was slow.The highest level of recovery is in Yuzhong District,and Banan District is the only one with a recovery level below 50%.(2)In this thesis a total of 25 urban indicators were collected for the construction of the flood resilience evaluation system,and 6 irrelevant indicators were excluded after doing correlation analysis with the flooded area,indicating that not all urban indicators are applicable to the construction of the flood resilience evaluation system,such as population density,total energy consumption,and the proportion of annual good air days,etc.(3)The spatial distribution of the resilience strength of the nine districts in the main city of Chongqing shows a more obvious "X" pattern,the overall average resilience index is only0.38,and there are more obvious differences in the strength of the nine districts.(4)This thesis analyzes and explains the difference of toughness strength among nine major districts of Chongqing from four dimensions: infrastructure,environment,economy and society.For example,in the dimension of infrastructure,the road length index plays a positive role in promoting the recovery of flood disaster,and the levees play a very important role in flood resistance.Green rate and sewage treatment capacity in the environmental dimension can help the region adapt to the flood disaster.From the perspective of contribution to resilience intensity,the indicators of economic dimension make the largest contribution,which are mainly because economy is the driving force of urban development and the basic support of the other three dimensions.The social dimension is mainly from the perspective of local residents.A large proportion of people with high educational level and young adults can effectively help reduce the loss of flood disasters and thus improve the resistance and resilience of a region to flood disasters.(5)For the main urban area of Chongqing,combined with the results of the flood resilience evaluation system,this thesis argues that the resilience can be improved according to the specific conditions of each district by considering three aspects: improving the level of regional economic development,strengthening urban infrastructure construction to promote ecological urban development. |
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