Regime Theory for Self-Formed Sediment-Bearing Channels

A dynamical framework–that of regime theory–on which to base a study of the behavior of channels that have formed boundaries from their own transported material or material of like nature is given. The most important system of natural channels to which the theory can be applied is that of the rivers of alluvial plains. Rivers, in general, are not susceptible to quantitative analysis except for certain broad effects. The theory has grown from the unrivaled mass of data provided by the irrigation canal systems of northern India. These canals were built by British engineers in India at the end of the nineteeth century and were extended regularly until they formed the largest, composite body of canals in the world.

It is shown that canals of the type considered provide formulas for the self-formation of width, depth, and slope. Rivers require two more formulas to give the general pattern of meandering. The developed laws fit into the framework of accepted hydraulics and generalize it. Although these laws apply to rivers, exactly as to canals, the disturbing influences in the former require judgment in the application of the formulas. Self-forming rivers cannot be described adequately in terms of the one flow formula of rigid-boundary hydraulics.