Identification of homogeneous regions for the purposes of regionalisation

This paper addresses the problem of identifying homogeneous subregions that can be considered to behave in a hydrologically similar fashion. The relative performance of several techniques is evaluated using the prediction of low flow characteristics in a heterogeneous group of 184 catchments located in southeastern Australia. The different approaches used are variously based on a combination of cluster analysis, multiple regression, principal component analysis, and the graphical representation of multi-dimensional data. The techniques presented allow assessment of the suitability of applying the derived regional equations to an ungauged catchment.