INTRODUCTION 



There is considerable evidence that logging roads are the primary source of 

 accelerated erosion and sedimentation on logged watersheds. Packer (1967) concluded: 



Of man's activities that disturb vegetation and soil in forests, 

 none are greater precursors of sediment damage to water quality 

 than the construction of roads. 



Numerous others have substantiated Packer's conclusion (Anderson 1954; Reinhart 

 and others 1963; Haupt and Kidd 1965; and Leaf 1966). 



Logging road construction is particularly damaging in highly erodible areas, such 

 as the 16 , QOO-square-mile Idaho Batholith (fig. 1), which is characterized by steep 

 topography and shallow, coarse-textured soils overlying granitic bedrock. Soils 

 derived from parent material of this type were the most erodible to be found in Oregon 

 and northern California (Anderson 1954; and Andre and Anderson 1961). Recognition of 

 such unstable soil conditions on steep batholith lands led to the initiation of the 

 Zena Creek logging study in 1959 (Craddock 1967). The study, which was a cooperative 

 effort carried out by the Intermountain Region and the Intermountain Station of the 

 USDA Forest Service, was conducted near the confluence of the South Fork of the Salmon 

 and the Secesh Rivers in the mountains of central Idaho. 



Part of the research effort included a study to evaluate the effects of jammer and 

 skyline logging systems on erosion and sedimentation in the Deep Creek drainage (Megahan 

 and Kidd In press). The purpose of this report is to explore types and rates of change 

 of the road erosion that occurred during the Deep Creek study. 



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