Geometry of River Channels

Hydraulic principles, as developed in firm boundary channels, appear insufficient to explain the form and profile of river channels. In nature, stream channels attain a most probable state that must fulfill the necessary hydraulic laws, but in addition, fulfills its degrees of freedom by tendency to equal distribution among velocity, depth, width, and slope. This principle is tested by the use of three examples. Another example explores the accommodation of a river channel to changing discharge. The last example is that of a river free to adjust its profile, velocities, depths, and widths to accommodate the downstream increase in discharge. Each of these examples appears to satisfy the postulate of this paper. The adjustment is toward minimum variance among the components of stream power.