| Since the 21st century,the trend of climate change and the process of urbanization have intensified social and economic losses of urban flood and significantly increased the flood disaster risk in urban areas.The research of social vulnerability can assess and identify vulnerable areas of flood disaster and propose corresponding planning and design strategies,which is an important approach to reduce flood risks and enhance climate adaptation abilities.Taking Nanjing city as the study area,the study analyzed the spatial heterogeneity pattern of social vulnerability in Nanjing from three dimensions of exposure,sensitivity and adaptation based on the assessment unit of street scale.On this basis,priority action zones of flood risk were delineated and flood adaptation strategies were proposed for different zones.Firstly,the concepts,analytical frameworks and assessment scales of social vulnerability were sorted out,and the concepts and assessment methods of flood risk were sorted out,as well as the research on social vulnerability oriented to urban flood,which laid a foundation for the assessment system and research methods.In addition,the study summarized the foreign adaptation strategies to flood disaster,analyzed and evaluated the underlying social vulnerability caused by these strategies.Secondly,the evaluation system of social vulnerability based on flood disaster of Nanjing was constructed.Taking Nanjing as the study area,the study area was divided into99 research units based on street scale to assess social vulnerability.Social vulnerability was divided into three dimensions: exposure,sensitivity and adaptability.Entropy method was used to get the weight,and the social vulnerability index was then calculated.Ternary graph coordinate system was used to classify social vulnerability types.Thirdly,the assessment results of social vulnerability were analyzed and summarized.The main conclusions are as follows: 1)The social vulnerability index of Nanjing showed distinct hierarchical structure and agglomeration characteristics,with the highest in exurban areas and the lowest in the junction between urban center and suburban areas.The "cold spot" were mainly located in urban center,and the "hot spot" were mainly located in exurban areas.2)The correlation between different dimensions of social vulnerability was significant,and there was a great difference of correlation between urban center and suburban areas.3)Six types of social vulnerability were identified in Nanjing,and the number of low–adaptability streets was the largest,and there were two main types of clusters in Nanjing.Fourthly,flood adaptation strategies were proposed based on the above evaluation results.According to the evaluation results of social vulnerability index and types,priority action zones of flood risk were identified and delineated,and flood adaptation strategies were proposed according to the social vulnerability characteristics of each zone.The study considered the natural characteristics of flood disaster and emphasized the impacts of social attributes.From the perspective of whole social vulnerability,the study integrated the natural and cultural elements,and discussed the correlation characteristics among various dimensions of social vulnerability.The conclusions of the study provided strategic suggestions for urban managers and stakeholders in risk management and planning design,which is of practical references to further improve the flood disaster response capacity of cities.Meanwhile,these research methods and conclusions will help to further improve the theoretical system of social vulnerability and reveal the complex interaction mechanism of urban system. |
