Risk Evaluation Of Ice Flood Disaster Of The Ningxia–Inner Mongolia Reach In The Yellow River

Among the major rivers in winter and spring in my country,the Yellow River flood has become one of the most prominent and most important flood events.Because of its special geographical location,channel characteristics and hydrometeorological conditions,the Ningmeng River reaches the Yellow River with the most serious glacial flood disasters.In winter and spring,the river section is prone to ice jams and high water levels,causing flood disasters,posing a serious threat to the lives of people in Qixian County on both sides of the strait,and causing significant adverse effects on local economic development.In response to flooding problems,in addition to the use of engineering measures,we should also pay attention to the important role of nonengineering measures.Risk assessment is an important part of disaster prevention and control decision-making,and risk assessment is one of the effective means to carry out flood prevention work.However,at present,there are few studies on the analysis of risk evaluation of ice flood disaster of the Ningxia–Inner Mongolia reach in the Yellow River and there are obvious deficiencies.In view of this,this paper is funded by the National Natural Science Foundation of China(51879116,51979024)to conduct research on the risk evaluation of ice flood disaster of the Ningxia–Inner Mongolia reach in the Yellow River.The main work and results are as follows:(1)Establishment of ice flood disaster risk evaluation index system of the Ningxia–Inner Mongolia reach in the Yellow River.This paper analyzes the characteristics of Lingqing in the Ningmeng River section during the flood season from1950 to 2020,and summarizes the characteristics and laws of the Ningmeng section of the Ningmeng section in the recent period(2000～2020).Based on the analysis of the formation conditions,influencing factors and the composition of the ice flood disaster system,as well as the analysis of the connotation of each subsystem,the Ningxia–Inner Mongolia reach in the Yellow River ice flood disaster risk evaluation index system is constructed.(2)Construction of evaluation model based on improved catastrophe theory evaluation method Aiming at the problem that the comprehensive evaluation value of the catastrophe theory evaluation method is too high and the evaluation values are relatively close,an improved method using the three-parameter exponential curve for regression analysis is proposed,and the calculation process of the improved method is deduced.The rationality of the improved method is verified by a numerical example,and a model of ice flood disaster risk assessment is established according to the proposed improved catastrophe theory evaluation method.(3)Application of the Ningxia–Inner Mongolia reach in the Yellow River ice flood disaster risk assessment model.The proposed improved catastrophe theory evaluation method was applied to the assessment of ice flood disaster risk in four banner counties on both sides of the Yellow River from Toudaoguai to Wanjiazhai,which determined the risk level of each study area.The evaluation results are basically consistent with the analysis of the actual situation in various regions,which verifies the reliability of the improved method.It can provide a reference for the scientific planning and rational deployment of the prevention and mitigation work of various banners and counties.