Investigating the goodness-of-fit of ten candidate distributions and estimating high quantiles of extreme floods in the lower Limpopo River Basin, Mozambique

AbstractWe compare ten candidate distributions for their goodness-of-fit in modelling the annual maximum daily flood heights in the lower Limpopo River Basin, Mozambique. The ten candidate distributions compared in this study are Generalised Gamma (GG), two-parameter Gamma, three-parameter Gamma, two-parameter lognormal, three-parameter lognormal, log-Pearson Type 3 (LP3), Generalised Extreme Value (GEV), two-parameter Weibull, three-parameter Weibull, and Gumbel distribution. The GEV, Gumbel, and GG were the best three distributions at Sicacate based on their ability to model the tails. The three-parameter Gamma, three-parameter lognormal and GEV were the best three distributions at Chokwe. Among the parameter estimation methods used were the maximum likelihood method and the method of L-moments. Goodness-of-fit was evaluated by means of Kolmogorov-Smirnov and Anderson-Darling tests, as well as P-P plots and simulation studies to check whether the distribution could mimic the observed values. Results of ...