higher than in rivers with mild slopes. These rivers generally have large 

 quantities of gravel available even near the mouth. The size of the system 

 and other hydrological and hydraulic factors also influence availability of 

 gravel. The abundance of mountain and foothill origin rivers and the fre- 

 quent availability of suitable gravel materials generally combine to favor 

 the location of material sites in these systems. The geographical location 

 of these rivers, and the topography through which they flow, directly affect 

 the type of channel configuration, a factor discussed in a previous section. 



353 



