Risk Assessment Of Flooding In The Old City Of Yingtan

With global warming,the frequency,intensity and damage caused by urban flooding in China are on the rise year by year.At the same time,with the increasing level of urbanisation,the rapid accumulation of urban population and wealth,the densification of various types of buildings and facilities,the continuous expansion of land use,the increasing height of buildings,and the continuous rise in road density,the sensitivity and vulnerability of the urban system to flooding have increased,and the situation of the city facing the risk of waterlogging has become more and more serious.Therefore,it is of practical significance to carry out research on urban flood disaster risk.In this study,flooding disaster risk is assessed in the old urban area of Yingtan City as an empirical area,and the main research contents are as follows:(1)Based on the relevant theories of urban flooding disaster and disaster risk,and starting from the three aspects of hazardous factors,sensitivity of the disaster-bearing environment and vulnerability of the disaster-bearing body,and in accordance with the process of risk identification-analysis-assessment-mitigation,it is determined to carry out urban flooding disaster risk management by using the indicator system method in conjunction with the scenario simulation method.(2)The geographic profile,rainfall data and economic profile of Yingtan city centre are sorted out in detail,and the risk identification is completed by drawing on existing research on flooding disaster risk indicators and combining expert opinions.The depth of inundation and the duration of inundation are identified as the risk indicators of disaster-causing factors;the type of urban sub-surface,ground elevation,slope,and the drainage capacity of the pipeline network under different recurrence periods are identified as the sensitivity indicators of the disaster-conceiving environment;the population density,road density,and the distance from the hospital are identified as the vulnerability indicators of the disaster-bearing body,and the indicator layer has a total of 9 indicators.(3)A one-and two-dimensional coupled urban stormwater model of the old city was constructed to obtain the hazard data of the disaster-causing factors.Two measured rainfalls were selected for rate determination and validation,design rainfalls with different return periods(1,2,3 and 5 years)were set to obtain the drainage capacity of the pipe network in the study area under different scenarios,and rainstorm simulations with different return periods(10,30 and 50 years)were set to obtain the inundation depth and duration of inundation in the study area.(4)With the help of Arc GIS software to superimpose the analysis of multiple indicator factors,the risk zones of flood hazard,sensitivity and vulnerability under different return periods were finally mapped.The results show that the risk of inundation in the study area increases with the increase of the return period.Among them,the hazard zoning is influenced by the inundation situation,the sensitivity zoning is mainly influenced by the elevation and drainage capacity of the pipe network,and the vulnerability zoning is closely related to the population density.The high and higher risk zones are concentrated around Bailu Culvert,Gandong Mall and the railway station,and the 8th primary school,while the medium risk zones are mainly located around Yingtan 4th Primary School and Longxiang Sub-district.