Before the close of the 18th century, the erosive capabilities of running water were not appreciated. Streams were believed to flow in valleys because the valleys were already there, not because the stream cut the valley. Catastrophism, with its emphasis on the biblical flood as the final stage in the shaping of the earth’s surface, obviously influenced this perspective (Morisawa 1968). By the late 1700s, however, geologists reasoned that the dendritic pattern of drainage nets gave evidence of erosion, as did the observation that valleys in headwaters are smaller than valleys downriver. Modern study of geomorphology focuses on the linkages among channel, floodplain, network, and catchment, and employs such diverse approaches as stratigraphic analyses, experimental studies of sediment transport in flumes, modeling of physical processes, comparisons of landforms, and sophisticated statistical approaches to gain greater understanding of the physical dynamics of river systems (Kondolf and Piégay 2003).
KeywordsDebris Flow Sediment Load Sediment Yield Sediment Supply Stream Order
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