Urban Waterlogging Risk Dynamic Assessment And Response Strategy Based On Bayesian Classification Algorithm

Urban waterlogging disaster management is a hot topic in the field of urban human settlement environment construction,and it is also an important content of how to scientifically plan and construct a city under the background of climate change and urban development.Urban floods caused by extreme rainfall have caused serious loss of life and property worldwide,posing a serious threat to social and economic development and urban ecological environment.Due to the fast urbanization and global climate change,the magnitude,frequency and intensity of urban flood susceptibility will be expected to be continuously increasing.It is of great significance to scientifically estimate the impacts of climate change and urbanization on urban waterlogging,so as to formulate effective urban waterlogging risk management measures.However,the research on urban waterlogging risk management under the comprehensive impact of climate change and urbanization is limited at present,and the practice of urban waterlogging disaster management is in urgent need of relevant technical guidance.Therefore,based on the integration of landscape architecture,hydrology,urban and rural planning,meteorology and other disciplines.A dynamic assessment framework of urban waterlogging risk in response to climate change and urbanization was constructed based on Bayesian classification model.The main research work and conclusions are as follows:(1)Future climate change and urbanization were Simulate based on the shared socio-economic path scenario.Firstly,the rainfall change under climate change was predicted by GCM model and statistical downscaling method.Then the future land use change was simulated by coupling system dynamics model and FLUS model.The results showed that compared with the reference period(2015-2020),the intensity and frequency of extreme rainfall in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA)continued to increase from 2021 to 2050.The constructed land area will increase consistently during the period of2020 to 2050 under three SSPs scenarios due to the rapid population increase.Conversely,projected cultivated land,forest land,and grassland will decrease consistently over the next30 years for all scenarios.The urban construction land was mainly concentrated in the central urban area of the GBA and spreading outward around the existing built-up area.(2)On the basis of simulating future climate change and urbanization,a dynamic assessment framework of urban waterlogging risk in response to climate change and urbanization is constructed based on Bayesian classification model.Taking the GBA as the research object,the temporal and spatial dynamic changes of urban waterlogging risk in the future in the GBA were evaluated.The GBA is facing serious urban waterlogging,with23.08% of the GBA is facing urban waterlogging above high risk,and continuously increase in the next 30 years.The urban waterlogging is spatially concentrated,the high risk is mainly distributed in the central urban area of the GBA,while the very low risk is distributed in the rural areas outside the GBA.Compared with the risk of urban waterlogging,temporal and spatial variation of urban waterlogging vulnerability changes slowly,and there is an obvious spatial aggregation phenomenon,forming two highly vulnerable clusters in Guangzhou-Foshan and Guanshen.Individually,urbanization has a greater impact on urban waterlogging risk than climate change.Under the comprehensive influence of climate change and urban development,urban waterlogging risk presents different growth trends under different scenarios.Under waterlogging showed a slow increase trend in SSP1-2.6,increased obviously in SSP2-4.5,and presents a rapid increasing trend in SSP5-8.5.In terms of spatial distribution,there is a significant spatial aggregation of urban waterlogging risks under climate change and urban development.Urban waterlogging risks above high risk are mainly distributed in the central urban areas of the GBA,while urban waterlogging risks of low risk and very low risk are distributed in rural areas outside the GBA.Under different scenarios,the expansion direction of urban waterlogging risk is the same,but the increase amount is not consistent.(3)Based on the results of urban waterlogging risk assessment,the mutual transformation matrix of green space and impervious surface was constructed to study the impact of green space proportion change on urban waterlogging.The results show that the conversion of impervious surface to green space can significantly reduce the area of high risk and medium risk areas,and improve the existing high risk and medium risk areas to cope with urban waterlogging,but the effect on the very high risk areas is not significant.When existing green space is transformed into impervious surface,the overall change of urban waterlogging risk is not obvious,but it has a significant impact on extremely high risk areas,that is,extremely high risk is very sensitive to the reduction of green space.Dynamic assessment of urban waterlogging risk can provide a theoretical basis for urban waterlogging risk control in response to climate change and urbanization,and provide a new perspective and technical guidance for scholars of landscape architecture to solve urban waterlogging disasters.