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0018j3 fundamental to the discipline of fluvial geomorphology' as recorded by Leopold. Wolman. and Miller (1964), Schumm (1977), Dunne and Leopold (1978), Richards (1982), and Leopold (1994). The adjustment of the channel size to the volume of through-flowing water was well- established by Leopold and Maddock (1953) in their concept of the hydraulic geometry of streams. Typically, the size of streams and rivers increases in the downstream direction such that there is a relationship between drainage area at a given location and many channel size and streamflow parameters. Even so, the size of the stream channel is more directly related to discharge than drainage area (Emmett, 1975). For illustrative purposes, several of these relationships between flow and channel geometry are shown for the claim sites in the Snake River system (Figure 15). A variety of observations suppon the generalization that alluvial channels are both adjustable and, over time, establish channel sizes and forms consonant with the flow and sediments available to them. In a given river reach, or length of stream, repeated measurements of cross sections of a channel reveal maintenance of the channel form as the river migrates across the valley floor (Leopold and Wolman, 1960). Similarly, observations of channel width following a period of high flood flows, show an increase in width and subsequent narrowing following a period of average or more normal annual flows (Wolman and Gerson, 1978;' Osterkamp and Costa, 1987). The influence of materials comprising the banks of the river channel on channel size and shape is illustrated by a set of gravel-bed rivers in the Colorado River basin (Andrews, 1984). Channel width increases as discharge at the bankfull-stage increases in channels with gravel boundaries. At the same time, for a given discharge, channels with vegetated banks, as opposed to those without, are narrower. Similar influences of bank material on channel form in rivers carrying sand and silt have been described by Schumm (1960). It is commonly observed that many, if not most, alluvial rivers are subject to episodic floods. That is, the flow ovenops the river banks and spills over the adjacent lands. Floodplains are formed by lateral movement of the channel and deposition of bars and by vertical accretion resulting from deposition of sediment by floods. To the extent that the adjacent land is the product of deposition by the existing river it is, by definition, a floodplain. The floodplain therefore is a flat area adjacent to the channel constructed by the river in the present hydrologic regimen. Deposits and surfaces other than the floodplain may exist on the valley floor. If they are alluvial, that is riverine in origin, they may constitute terraces (topographic surfaces) or terrace deposits laid down by the river under a different and earlier hydrologic regimen. Although there is some evidence to suggest that the bankfull stage, Le., height of the floodplain, in many rivers corresponds to a discharge of constant frequency, for example every I to 2 years (Wolman and Leopold, 1957; Nixon, 1959; Emmett, 1975), variability is encountered among river sites in a given region and in different regions (Williams, 1978). Similarly, in some rivers there is a close correspondence between flows during which much of the annual sediment load is , Fluvial refers to of, or pertaining to, rivers; produced by river action. Geomorphology refers to that branch of both physiography and geology which deals with the form of the earth, the general configuration of its surface, and the changes that take place in the evolution of landforms. United States' Expert Report Disclosing Methodologies for Quantification of Organic Ad Claims Consolidated Subcase No. 63-25243 13