A COMPARISON OF 4 DISTRIBUTIONS USED IN FLOOD FREQUENCY-ANALYSIS IN BANGLADESH

This paper discusses how lognormal, Gumbel and log-Pearson type 3 dist ributions were eliminated as candidates for modelling at-site annual m aximum discharge series in Bangladesh. Among candidate distributions, the generalized extreme Value distribution best represented the statis tical characteristics of observed data. Comparisons of distributions w ere based upon the root mean square deviation in fit, the probability plot correlation coefficient and L-moment ratio diagrams. The last met hod assesses whether a candidate distribution is capable of simulating the site-to-site variation in statistical characteristics that is pre sent in observed flood samples.