Study On Vulnerability Assessment Of Waterlogging Disaster And Improvement Of Disaster Resilience In Old Urban Communities

Since the beginning of the twenty-first century,the global climate has been aggravated by the influence of human activities,and extremely bad weather represented by heavy rains has been frequent,posing a serious threat to the development of cities.Among them,due to the aging of infrastructure and incomplete functional configuration,old residential areas have become the hardest hit areas of cities with major climate disasters.Although China has launched the construction of sponge cities and the transformation of old residential areas since 2014,many problems have still been exposed and more scientific guidance has been called for.This study focuses on the problem of waterlogging disasters in old communities,based on the perspective of catastrophology,limits the scope of research to the community level,and explores the relationship between disaster vulnerability and disaster resilience,which embodies the objective law of the development and change of things,which are mutually superficial and complementary,and play an important role in the management of waterlogging disasters in old communities.In this paper,taking the old residential areas under the jurisdiction of Changsha County,Changsha City,Hunan Province as an example,the vulnerability characteristics of waterlogging disasters in old communities are explored,and the characteristics of waterlogging disasters in typical communities are sorted out and analyzed from four aspects: the risk of disaster-causing factors,the sensitivity of pregnant disaster environment,the vulnerability of disaster bearers and management factors.At the same time,the Delphi method was used to establish an index system for the vulnerability evaluation of waterlogging disasters in old communities,the AHP-entropy weight method was used to determine the index combination weight,and based on the extendable object element analysis and cloud theory,the combined weight-cloud object element model of the vulnerability assessment of waterlogging disasters in old residential areas was established.In this paper,the model is used to evaluate the vulnerability of Gongchengjiayuan Community,which proves that the model is effective,the vulnerability of waterlogging disasters in Gongchengjiayuan Community is extremely high,and the main influencing factors are the risk of disaster factors and the sensitivity of pregnant disaster environment,indicating that the model has a guiding function for the transformation of old residential areas.According to the vulnerability evaluation results,this paper designs and simulates the improvement of disaster-friendly resilience improvement of the external space of Gongchengjiayuan Community.In this study,the SWMM model is selected to establish a generalized model of Gongchengjiayuan Community before and after optimization,set different precipitation reproduction periods of 1-100 a,conduct numerical simulations,analyze the total amount of rainwater runoff before and after optimization,comprehensive runoff coefficient,drainage peak,peak occurrence time and other rainwater runoff conditions and overflow rainwater wells,water accumulation depth,water accumulation time and other water accumulation conditions,simulation proves: increasing the proportion of permeable area in the old community and increasing the biological detention facilities will effectively enhance the rainwater infiltration and retention capacity of the old community.It can effectively improve the resilience of waterlogging disasters in old communities.Combined with the evaluation results of the vulnerability assessment of waterlogging disasters in old residential areas,this paper comprehensively proposes a plan to improve the resilience of waterlogging disasters in old communities.