Mechanism and conditions for change in channel pattern

Using the principle of maximum entropy and field data, this paper derives t he mechanism and conditions for change in the channel pattern of alluvial r ivers. Theoretical analyses indicate (i) the mechanism of formation of diff erent channel patterns in a river system is one of maximizing entropy of th e system under different local flow and boundary conditions, and (ii) the r iver pattern with sinuosity S = pi/2 approximate to 1.57 conforms to the pr inciple of maximum entropy. The equations governing the change in a channel pattern are derived and thresholds, as the conditions of channel pattern c hanges, determined, using theory and field data from 70 alluvial rivers hav ing different channel patterns. The result of this study suggests that rive r management and training works should help rivers achieve and maintain a s inuosity S close to 1.57 and the stability criterion S-cr > 0.2.