Research On The Calculation Method Of The Critical Rainfall Of Flood Disaster In Hexi Inland River Basin

Flash flood is a kind of disaster caused by rainstorm.As for the factors that affect the flash flood,precipitation is not only an integral part,but also an important factor to induce flash flood.In the process of a flash flood disaster warning,rainfall is a extremely sensitive and active factor that is possible to determine whether or not the flood disaster can be accurately defined.It is frequently that occours flash floods in Hexi inland river basin in Gansu Province with the grading standards on the prevention and less rain sites distribution.Using the the same calculation method of critical rainfall is too single in the study area,and can not accurately determine the critical value of rainfall flood disasters in each catchment,so it is necessary to study the determination of critical rainfall in the different conditions.This paper from the perspective of the rainfall warning,considering the soil moisture,studies the methods of critical rainfall flood disasters in Hexi area,discusses the calculation method suitable for Gansu Province in the inland river basin,and combines with the promotion to provide technical support for the prevention of flash flood disasters in Gansu province.The main results show as follows:(1)This paper presents 3 methods of the the inverse-water level method,the relationship between rainfall and runoff curve interpolation method and single station critical rainfall,summary from the three aspects of the basic principle of each method,steps of the calculation and comprehensive analysis.(2)Choose the 2 typical villages those are Cheng Village three groups(Jiangou)and Li Fu Village seven groups(Liu Shugou)in Liangzhou District in Wuwei city as an example,calculate of designing storm and designing flood via “tieyiyuan” method and rational formula,obtain the control section of the flow stage relation curve of water level and acquisition,disaster in flow measurement,soil moisture content calculation,provide the basic data for the inverse-water method and the relationship between rainfall and runoff curve interpolation method to calculate the critical rainfall.(3)Collect rainfall data of the rainfall station and hydrological station in 2 typical disaster object regions to selecte the maximum rainfall precipitation in different periods.Process the data to provide the basic data for single station critical rainfall method of the critical rainfall calculation.(4)Calculate the critical rainfall value of small watershed by inverse-water method,the relationship between rainfall and runoff curve interpolation method and single station rainfall threshold method for 2 typical disaster objects,analysis of flood disaster rainfall warning index.(5)Through the analysis of the 3 methods,this paper states that inverse-water method based on the assumption the critical rainfall of flash flood disasters analysis of the most universal method is compatible in region lack of rainfall data,and that is can be extended.Rainfall runoff relationship curve interpolation method based on the designing storm and designing flood point to simulate to get the critical rainfall value.It does not reflect the concept of disaster prevention object present flood control capacity,as the inverse-water method is superior.The single station critical rainfall method is only based on the analysis of rainfall data,and can not accurately reflect the critical rainfall of the specific disaster prevention object.(6)Show the method of hydrological model based on physical mechanism of rainfall runoff that will become the main calculation method of critical rainfall as the engineering measures in Hexi inland basin in the rainfall station flood non continuously improving,and can realize the real-time dynamic early warning flood disasters,and reduce the losses greatly caused by flood disasters with the development of space and good.application prospect...