Evaluation of frequency distributions for flood hazard analysis

Many different frequency distributions and fitting methods are used to determine the magnitude and frequency of floods and rainfall. Ten different combinations of frequency distributions and fitting methods are evaluated by summarizing the differences in the 0.002 exceedance probability quantile (500-year event), presenting graphical displays of the 10 estimates of the 0.002 quantile, and performing statistical tests to determine if differences are statistically significant. This evaluation indicated there are some statistically significant differences among the methods but, from an engineering standpoint, these differences may not be significant.