Early warning index of flash flood disaster: a case study of Shuyuan watershed in Qufu City.

Flash flood disaster is one of the important natural disasters, bringing harm to human life and causing serious economic losses, so it is urgent to improve the accuracy of flash flood warning. To determine the critical rainfall and early warning indicators of disaster prevention objects, the Shuyuan Watershed of Qufu City Shandong Province was selected as the research object, the key disaster prevention objects were screened and finally, Hengmiao Village and Gaolou Village were selected as typical disaster prevention objects. Empirical analysis method, Storm analysis method, and model analysis method were used to calculate the critical rainfall at different times under different soil water content conditions, compare and analyze the rationality and existing problems of these three methods, and comprehensively determine the indicators of typical disaster prevention objects under different circumstances. The results show that the value of the index calculated by the storm analysis method is small and calculated by the model analysis method is large. This paper can improve the accuracy of flash flood warning, select the critical rainfall calculation method according to local conditions, accurately calculate the parameter values, and deal with the problem of effective early warning in the region as a whole.