Sinuosity

Sinuosity is the ratio of stream length to valley length. It can also be described as the ratio of valley slope to channel slope. Meander geometry characteristics are directly related to sinuosity, consistent with the principle of minimum expenditure of energy. Langbein and Leopold (1966) suggested that a sine generated curve describes symmetrical meander paths, permitting the estimation of a radius of curvature for meander bends, as developed from data analyses related to meander wavelength and channel sinuosity. Applying the same analyses techniques to an expanded data set, Williams (1986) found highly significant relations between predicted vs. observed values for radius of curvature and channel sinuosity for 79 streams.

Sinuosity, however, carries the least weight of all the criteria used to delineate Level II morphologies. It is used primarily as a channel plan-form and mapping indicator for Level I classification, since it is based on easily observable and interpreted patterns. Sinuosity can be modified by bedrock control, roads, channel confinement (lateral containment), and vegetation. As channel gradient and dominant particle size decreases, there is generally a corresponding increase in sinuosity. Sinuosity can best be measured using aerial photography as previously described in Level I classification.