Study on method of flash flood warning in lack-data watershed

Based on frequency method and threshold-based methodology, the critical rainfalls of 1h, 3h, 6h and 24h corresponding to the soil moisture content of 25%, 50%, 100% respectively were calculated, which can be used as flood warning standard. Take the DaPoLing basin as the case, with the application of contingency table, ten floods were chose to test the accuracy of flash flood warning method, the results show the forecast accuracy for flood was larger than 90%,the fail to report was zero, that is to say the method of critical rainfall used on flash flood warning is feasible