River Metamorphosis

Data collected from stable alluvial rivers on the Great Plains of Western United States and on the Riverine Plain of southeastern Australia are used to demonstrate that channel width, depth, shape, meander wavelength, sinuosity and gradient are significantly related to the quantity of water and to the type of sediment load moving through these channels (ratio of bed-material load to total sediment load). Frequently during geologic time, complete alteration of river morphology (river metamorphosis) has occurred as a result of climate changes, whereas during historic time river metamorphosis occurs as a result of man induced variations of hydrologic regimen. Geologic and historic examples of river metamorphosis are used to support the empirical relations and to form the basis for deductions concerning the long-term reaction of a river system to man-induced changes of hydrologic regimen.