Bank strength exerts a significant influence on river channel geometry, but quantification of this relationship has been limited to only a few specific circumstances. This is due to both the complex nature of bank strength and the difficulty in incorporating its influence in river channel geometry relations. In order to undertaken an integrated analysis of wide-ranging field observations, this study applies a recently developed multivariate model of channel geometry. When the banks of a number of laterally stable streams are categorized on the basis of the bank sediment and vegetation, the multivariate model yields numerical indices of bank strength. Within the range of the data analysed, bank strength can produce a three-fold change in channel width and a two-fole change in depth corresponding to about a 1.6-fold change in cross-sectional area.