34 BULLETIN 1430, IT. S. DEPARTMENT OF AGRICULTURE 
to concentrated rainfall, most of these streams have during floods 
high turbidity. If there have been no clearings on the headwaters 
of streams within these regions, or if the surface has not been de- 
nuded or exposed by fires, erosion is slight, there is a small quantity 
of solid burden, and silting threatens the capacity of storage reser- 
voirs only to a slight degree. If there is excessive erosion due to soil 
exposure, it is possible to reestablish forest conditions and by doing 
so reduce erosion and lessen sedimentation. 
