determining river behaviour requires interpretation of geomorphic fluvial processes from observation of geomorphic features. river behaviour is interpreted at three flow stages: 'low flow' (or 'baseflow'; i.e. under typical conditions); 'bankfull' stage (in the rising stage of a flood, when stream power is at its highest and water has reached the top of the river banks); and 'overbank' stage (when a flood spills over the top of the river banks and onto the floodplain). interpreting river behaviour requires expertise in geomorphology.