Research On The Indicator System And Assessment Method For Special Physical Examination Of Urban Waterlogging Risk

With the increase of extreme rainstorm events in recent years,the risk of urban waterlogging has become a prominent issue in the construction of human living environment security,which is a concentrated manifestation of "urban disease" in urban planning and construction.China has established a "city physical examination" assessment mechanism as an important manifestation of the modernization of urban governance system and governance capacity,and has built a multi-criteria evaluation system from problem diagnosis,rectification to improvement,and various departments have responded positively and proposed corresponding assessment indicators under the guidelines of disaster prevention and mitigation and safety and resilience.In order to respond to the overall evaluation requirement of the safety and resilience target of "city physical examination",the risk of urban waterlogging is included in the assessment mechanism,the causes of urban waterlogging are fully analyzed,the problems of method selection,indicator system selection and monitoring method selection in the process of urban waterlogging risk assessment are pointed out,and the concept of "urban waterlogging The concept of "special physical examination of urban waterlogging risk" is proposed,24 evaluation indicators in 5categories are established as the indicator system of the special physical examination,the construction method of the standard threshold of urban waterlogging risk is analyzed from different perspectives,and the process and evaluation method system of the special physical examination are proposed.The main results are as follows:(1)It shows that the existing waterlogging risk assessment system still lacks consideration of the formation mechanism of urban waterlogging and evaluation of socio-economic factors and urban differences;in the selection of indicators,the indicator system based on the "four factors" method has the limitation of being indirect and cannot directly correspond to the causes of waterlogging,and it is difficult to directly guide the formulation of waterlogging prevention and control plans;in the assessment method,there are still problems of unclear assessment process,lack of research on the determination method of waterlogging risk thresholds,and lack of basis for the selection of monitoring targets and technical methods for waterlogging monitoring.(2)According to the causes of urban waterlogging,the evaluation indicators are selected from the basin flood control capacity,the natural disaster-bearing capacity of the sub-base,the capacity of "large-small-micro" drainage system,the risk protection capacity of key areas and personnel,and the emergency management capacity at multiple levels,taking into account the mutual influence and effect of multiple factors,and establishing a special medical examination indicator system as a special evaluation mechanism of waterlogging under the goal of urban safety and resilience.(3)In order to make the risk of urban waterlogging quantifiable,the formulation principles and influencing factors of urban waterlogging planning and design standards are analyzed,the definition methods of various risk thresholds of urban waterlogging risk assessment under different perspectives of urban waterlogging predisaster warning,disaster-bearing capacity and post-disaster loss are proposed,and the methods of dividing the corresponding thresholds of rainfall and waterlogging occurrence and property damage assessment are proposed.(4)According to the assessment mechanism of city physical examination,decompose the calculation method of each indicator,propose the special physical examination process of city self-examination and third-party assessment,compare the differences in the period,purpose,mode and department of the two methods,and select Weifang City in Shandong Province as the third-party assessment case of the special physical examination,the results point out that the city has insufficient flooding capacity of local river sections,high risk of waterlogging in local areas,urban stormwater system The drainage standard is low and the large drainage system is missing,based on which the flood prevention planning guideline strategy is proposed.By analyzing the elements of waterlogging monitoring at different scales and two monitoring methods,both manual and intelligent,the proposed methods of special physical examination of urban waterlogging risk under the objectives of early warning and waterlogging monitoring are proposed.The establishment of special physical examination of urban waterlogging risk can provide theoretical and technical support for the accurate identification of urban waterlogging risk problems and the formulation of waterlogging prevention and control plans.