A method for characterising longitudinal irregularity in river channels

A method for analysing longitudinal variations in cross-sectional shape and channel slope is developed and demonstrated with an application to the Wimmera River, Australia. The method involves characterising the geometry and spatial location of individual cross-sections using four parameters and then conducting statistical analyses of the parameters from a set of cross-sections. The method extends the general characterisation of natural channels, allows examination of the spatial characteristics of stream channels, allows stochastic generation of stream channel cross-sections and can provide input into hydraulic and stream habitat analyses. The application to the Wimmera River identifies longitudinal trends and variability in cross-section characteristics, including quantification of differences in channel characteristics associated with a quasi-periodic switching between two different channel plan forms (single-thread and anastomosing).