The utility of L-moment ratio diagrams for selecting a regional probability distribution

L-moment ratio diagrams are increasingly being used in the literature for s electing a probability distribution function for regional frequency analysi s. Two graphical methods are often used in the distribution selection proce ss, the sample average and a line of best-fit through the sample L-moment r atios. Examples of homogeneous and heterogeneous regional samples are simul ated to illustrate the utility of the two distribution selection methods. D istribution selection for homogeneous regional data is best based on the sa mple average and not on a line of best-fit through the data points. For ver y heterogeneous regional data, exhibiting a large range in the distribution s shape parameter, the line of best-fit is useful for distribution selectio n. These results emphasize the importance of using heterogeneity tests in c onjunction with L-moment ratio diagrams.