Geometry of Rivers in Regime

An analytical method has been developed for computing the self-adjusted geometry of sand-bed rivers based upon a sediment discharge formula, a flow resistance relationship, and the concept of minimum stream power. Regime rivers with low values of discharge Q and slope S are characterized by small width-depth ratios (generally less than 30) that are not sensitive to the change in slope or discharge. Most regime canals belong to this category. But for larger values of Q or S, or both, the results show that regime rivers may have large width-depth ratios sensitive to the changes in Q or S. As Q or S increases the width-depth ratio of a regime river may become so large that it indicates a braided channel pattern. However, a much smaller width-depth ratio under this situation is also a possible stable geometry. The stable geometry was obtained from the stream power analysis wherein each stable configuration is assumed to correspond to a minimum stream power for the given constraints.