Development of Bed Features

The concept of unification, the opposite of branching theories used in biological sciences, is introduced as a new avenue to investigate the behavior of bed features in alluvial channels under unidirectional flow. The approach starts with the theoretical concepts initiated by Exner, according to which the features propagate at speeds inversely proportional to their heights. This leads to coalescence and rearrangement of the general pattern of bed features. Numerical experiments show that an initial large number of arbitrary bed disturbances rapidly reduces to a small number. If one feature reaches the maximum height for given flow conditions, smaller features pass through it. An initial uniform distribution of heights of disturbances slowly changes into a broad distribution of heights with some at the maximum height, similar to what is observed in nature.