An investigation to identify homogenous regions : a case study for New South Wales, Australia

This study focuses on identification of hydrologically homogeneous regions in New South Wales (NSW) from 88 selected sites for regional flood frequency analysis. The heterogeneity measure proposed by Hosking and Wallis (1993) has been adopted for this study amongst the various available techniques to form homogenous region. This method applies L moments to check for homogeneity. L moments for all the 88 sites have been computed and an investigation for discordant sites has been carried out. This has been done in two steps: (i) considering all 88 sites as a single group and (ii) dividing the 88 sites into two groups based on their drainage divisions. The effect of the discordant sites has been examined both individually and as a group. The overall results show that the effect of the discordant sites on heterogeneity measure is negligible and no homogeneous regions can be established in NSW, which is similar to the findings of previous studies.