Disaster Resilience Assessment And Enhancement Strategies For Urban Old Communities Under Flooding Scenarios

In the context of global extreme weather and accelerated urbanization,various disaster risks are frequent,causing serious loss of life and property and many adverse effects on the sustainable development of cities and communities.Under flooding disaster scenarios,communities,as the basic unit of urban disaster risk management and the basic unit of human life,are generally less resilient to disasters in old communities due to their long construction age,low level of building disaster prevention,and poor supporting facilities.Therefore,the study of flood risk in old communities based on the resilience perspective appears to be crucial for enhancing community resilience to secure urban development.This paper starts from the perspective of the whole cycle of emergency response under flooding,constructs an index system for evaluating the disaster resilience of old communities against flooding based on the PSR model,establishes an evaluation model using BP neural network with the disaster resilience of old communities as the research unit,and finally evaluates the disaster resilience of old communities in Jingkou District,Zhenjiang City,Jiangsu Province as an example,and proposes a strategy for improving the disaster resilience of old communities against flooding based on the research results.The research of the paper is mainly carried out in the following aspects:（1）Define the concept and connotation of flood disaster resilience in old communities.Through literature analysis and flooding cases,we comprehensively analyze the concepts and connotations of disaster resilience of flood prevention in old communities.The origin and evolution of the concept of resilience are sorted out,the performance characteristics of resilient communities are clarified,and the connotation of the role of disaster prevention resilience and the model of the mechanism of action are summarized and analyzed.In this way,the concept of flood resilience of old communities is proposed,and the assessment methods,characteristics,and research framework of flood resilience of old communities are dissected.（2）Constructing an evaluation system of flood disaster resilience of old communities based on PSR model.Based on the concept and connotation of flood disaster resilience of old communities,combined with PSR model（pressure（P）-state（S）-response（R））,the flood disaster resilience of old communities is decomposed into pressure layer resilience（P）,state layer resilience（S）and response layer resilience（R）,with 7 indicators in the subordinate element layer and 22 indicators in the indicator layer.On this basis,the combination of improved hierarchical analysis and entropy weighting method is combined to obtain the evaluation weights.Finally,a well-structured and logical old community flood disaster prevention and resilience assessment index system is built.（3）Establish PSR-BP neural network evaluation model.The aforementioned evaluation weights are substituted into the BP neural network evaluation model,and the MATLAB high-level language program is used to implement the algorithm,set the number of network layers,excitation function,learning rate,etc.,so as to establish the PSR-BP neural network evaluation model.After learning and training,the BP neural assessment model has a goodness-of-fit R² close to 1,error（Mu）=1×10^-5,and the relative error between test results and expected output values is small and close to 0.It reflects that the assessment model has high network generalization ability,fitting accuracy,and is suitable for quantitative assessment of disaster resilience of old communities under flooding scenarios.（4）Assessing flood disaster resilience of old communities in Jingkou District,Zhenjiang City.Using the old community flood disaster resilience assessment model（PSR-BP neural network）,three old communities,A,B and C,were selected as the research objects within the scope of Jingkou District of Zhenjiang City,and relevant data were obtained through various ways such as on-site exploration,actual research and face-to-face interviews of the old communities,and finally the total score of flood disaster resilience of different old communities and the cross-sectional comparison were obtained,and according to the scores,the The level of flood disaster resilience of the above old communities（Community B>Community C>Community A）was determined based on the scores to further verify the applicability and operability of the assessment system.（5）Exploring strategies to improve disaster resilience of old communities under flooding scenarios.Combining the analysis results of the proposed assessment framework,methods and models,the shortcomings and deficiencies of flood resilience of old communities are summarized.The internal and external logic of the three dimensions of pressure level resilience（P）,state level resilience（S）,and response level resilience（R）are explored,and the influencing factors are selected from the systematic correlations among the influencing factors of disaster prevention resilience of urban old communities under flooding disaster impacts,and specific strategies for improving flooding disaster prevention resilience of old communities are refined for each of the three dimensions.