Infrequent extreme floods may cause significant changes in stream channels. However, bankfull stage flows transport the greatest quantity of soil and stone over time, because the bankfull stage occurs about once every year or two. The bankfull stage is related to channel dimensions such as width, and to the meandering pattern of a stream. Entrenchment describes the relationship of the river or stream to its landscape. Entrenchment is the degree to which a stream or river is cut into the valley floor, and is calculated as the width of the flood-prone area to the stream's width at bankfull stage.
Sinuosity is the ratio of stream length to valley length.
A straight stream has a sinuosity of 1. Stream meander characteristics are directly related to sinuosity. A closer approximation to equilibrium is achieved by meandering than non-meandering stream pattern. Channel bed and bank materials influence the stream's cross-section shape and linear pattern. These materials also determine the extent of sediment transport.