Study on the time conversion method of early warning indicators of flash flood disaster: A case of Qufu City, Shandong Province.

To solve the problem of imperfect flash flood warning indicators in mountainous watersheds, this study proposes a conversion method of critical rainfall for different warning periods on the basis of the existing stormwater calculation formulae and applies it to typical mountainous watersheds. The specific method is to use the multiplicative power function method to interpolate and extend the early warning indicators of other time periods through the known early warning indicators of some time periods, apply them to Hengmiao Village and Gaolou Village, typical disaster prevention objects in Qufu City, Shandong Province, China, and verify the rationality of the results. The results show that the multiplicative power function method interpolates and extends the early warning indexes of 0.5, 1, 3, 6, 12, and 24 h under the same soil moisture condition. Based on the historical actual mountain flood disaster rainfall, the correlation coefficient R2 and Nash coefficient Ens are calculated to be 0.85 and 0.86, respectively, which verifies the applicability of this method. This study provides a convenient and quick way to unify the time series of regional early warning indicators and a feasible way for other regions to study regional overall early warning.

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.