a continuous process of erosion and deposition; erosion takes place on 

 the outside bank, downstream from the midpoint of the meander bend and 

 deposition occurs on the downstream end of the next point bar downstream. 

 The rate of downvalley shifting varies from one river to another. The rate 

 and direction of shifting is much more predictable than the lateral shifting 

 of braided channels. A result of nonuniform shifting is channel cutoffs. 



The floodplain width of a meandering river is often roughly equal 

 to the meander belt width, which is the average width from the outside 

 of one meander bend to the outside of the next opposite meander bend (Figure 

 20). High-water channels on the inside of point bars are typical on meander- 

 ing rivers. Sediment transport in meandering rivers is typically moderate. 



Sinuous Configuration. A sinuous river is similar in plan view to 

 a meandering river except that its sinuosity is between I.I and 1.5 (Figure 

 22). In sinuous rivers, point bars are smaller and downvalley shifting 

 is generally less than that of a comparable-size meandering river. Other 

 than the greater stability, sinuous rivers are quite similar in form and 

 hydraulic characteristics to meandering rivers. 



Straight Configuration . A straight river flows in a single channel 

 with a sinuosity less than I.I (Figure 25). The thalweg, or deepest part 

 of the channel, typically wanders back and forth within the channel with 

 alternate ground bars formed by sediment deposition opposite those locations 

 where the thalweg approaches the side of the channel. The alternate bars 

 may or may not be exposed at low flows. Rivers with a long reach of straight 

 channel pattern are much less common than rivers with other configurations. 

 Banks of straight channels are expected to be relatively stable. Sediment 

 transport is likely to be light to moderate in these systems. 



Other Processes. Rivers with any configuration may be found in narrow 

 mountain valleys and on alluvial fans. Rivers in these locations have dif- 

 ferent processes of erosion and deposition than those described for the' 

 typical river with the same configuration. Channel configurations of moun- 

 tainous rivers are typically not controlled by alluvial processes, but 



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