Study On The Influence Of Rain Type In Watershed On The Critical Rainfall Of Mountainous Flooding Disasters

At present,the flash flood warning system has been widely applied to most provinces(cities),the critical rainfall is an important indicator of flash flood warning.In the calculation and calculation of torrential floods,the design of rain is the commonly used parameter in the calculation of production and utilization,and the use of different rain patterns will obviously affect the design flood peak and so on,leading to the change of the critical rainfall.In the current analysis and calculation,the design of the rain is often used in the Atlas,hydrological manual in the large and medium-sized watershed data derived from the rain,the rain can adapt to the small watershed to achieve the critical rainfall? In addition,the global climate continues to warm,extreme rainstorms often occur,Atlas rain type of the critical rainfall can meet the extreme rainfall to form a disaster warning accuracy requirements? In order to solve the above problems,this paper takes the typical disaster prevention objects of the small watershed in the province of Henan Province as an example.Based on the analysis of the rainstorm and flood data of the small watershed,on the basis of analyzing the rationality of the comprehensive rain and production and drainage schemes in the small watershed,The study of the influence of the critical rainfall on the mountain flood disaster is of great significance to guide the real-time warning of flood disaster.The main contents and achievements are as follows:(1)According to the measured rainfall data of the hydrological station of the Peixihe hydrological station in Xinxian County of Henan Province,the temporal and spatial distribution characteristics of the rainstorm in the small watershed are analyzed in detail.The results show that the actual rainfall in the small watershed in the study area often has bimodal rain rainfall,and there is a difference in the single peak rain pattern recommended by the?Design of Storm Flood in Henan Province?(84 Atlas).(2)Based on the long-term measured rainfall data,the short-duration design of rainwater in the small watershed of the Peihe River Basin is deduced by the PC rain model and the same frequency analysis model,and the extreme rainfall type is deduced according to the recent extreme rainfall data.The results show that the predicted rain type is bimodal rain type,which is similar to the temporal and spatial distribution of rainstorm in the small watershed.The rain pattern,the maximum rain peak,the same frequency analysis method and the recent rainstorm,Rain front.(3)According to the data of the long series of rainfall and flood in the Pei River Basin,this paper analyzes the rationale of the calculation method and parameters of the production.The results show that the rainfall-runoff curve of the mountainous area in the mountainous area of ?Design of Storm Flood in Henan Province?(84 Atlas).The unit line provided by the national working map is used to calculate the flow,And the actual flood peak is closer,the production and convergence program applies to the study area.(4)The influence of rain on the critical rainfall was analyzed by using the rainfall runoff curve interpolation method to calculate the critical rainfall corresponding to different rain patterns.The results show that the critical rainfall is 1h and 2h in the early warning period,and it is not the same as the critical rainfall of the rain pattern in the chart.The critical rainfall is 3h and the critical rainfall The error period is between 5% and 25%;the warning period is 6h warning period,due to the double peak rain type,and the rainstorm in the figure shows the critical rainfall has obvious difference,the error is 10% ~ 50% of the between.It can be seen that the rain type derived from the rain pattern of the map can not be fully adapted to the small watershed,and the difference of rain type has a great influence on the critical rainfall.According to the recent weather forecast information,,On this basis,a reasonable choice of early warning indicators,accurate release warning instructions.According to the calculation method of the critical rainfall which is commonly usedThe research contents and results of this paper can supplement the practical and theoretical research support for the calculation of the critical rainfall of the mountain torrent,so that the warning is more refined and diversified,and it has reference value for the actual flash flood warning work.