The Research And Applications Of The Methods For Warning Indicators Of Flash Floods In Small Watershed Areas

With the improvement of our capacity to control flood in our rivers and medium-sized reservoirs,the weak coverage that in small watershed areas in Hilly mountain flood control capacity become increasingly outstanding, has become a short board in China’s disaster prevention and mitigation system, severely restrict the development and construction of the flood control system of Perfection. Because of the Small Watershed in Hilly Area in Jiangxi Province have the special geographical location, climate rainfall, the number of injuries and property losses caused by the torrential flood disaster losses has been accounted for a larger proportion and there is a rising trend.Taking Ji’an City Anfu County Xiao small River Basin as an example for the study, in the collection of the hydro-meteorological, river systems, historical flood disasters and other information combine with the Torrential Flood Control in the region, statistical induction and Storm critical curve for flood disasters was designed to determine the early warning indicators and early warning processes in Xiao Small River Basin.For statistical induction,process within the consumer River Basin 7 rainfall stations(including Peng Hydrological Station Square) from 1982 to 2014, 32 years of daily rainfall and hours of rainfall data from the perspective of mathematical statistics, calculated the study region’s each time critical rainfall threshold value, do the reliability analysis to the threshold value and design the early warning process. For rainstorm critical curve which described in hyperbolic function,using each time maximum design surface rain under the same frequency with the flash floods and minimum critical rainfall as a special point to solve function expressions to draw to 1d and 1h rainfall and its corresponding cumulative rainfall as cross and ordinate to the critical curve rainstorm warning diagram. Also analyzed the sensitivity of different parameters to Storm critical curve and analysis effect.Finally, based on the design of two different types of early warning procedures,combining the advantages of both methods,set rainfall as early warning level criterion,considering two constituent elements which are the rainfall intensity and accumulated rainfall, establish the early warning procedures, coupled with a corresponding warning measures, preliminarily constitute a flash flood warning scheme in Xiao small river basin,provide some reference for mountain flood prevention work in the study area.