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Kondolf: Cumulative Effects in the Sequoia National Forest 2 



excessive sediment derived from extensive timber harvesting many 

 miles upstream in the watershed over two decades ago. 



Cumulative Effects are Evident in the Sequoia National Forest 



As acknowledged by US Forest Service fisheries biologists, 

 cumulative watershed effects are already evident in streams of 

 the Sequoia National Forest as a result of logging road 

 construction, timber harvesting, and livestock grazing. In 

 numerous visits to the Sequoia National Forest from 1989 to 1993, 

 I have observed numerous cases of erosion from concentrated 

 runoff from logging roads and fresh deposits of sand-sized 

 sediment extending directly into stream channels. J| 



Many streambeds within the Sequoia National Forest contain 

 large amounts of sand, which can have many detrimental effects on 

 aquatic habitat, ranging from reduction in pool habitat to 

 reduction in substrate suitable for invertebrate colonization. 

 For example, gravel in Osa Creek (sampled 140 feet downstream 

 from USFS 20S25 Road crossing in October 1989) contained 24 

 percent finer than 0.85 mm, twice the percentage generally 

 considered acceptable for use by spawning salmonids. 



Based upon my observations of sediment directly entering 

 stream channels and my comparisons of channels draining 

 undisturbed and disturbed watersheds elsewhere in the Forest, I 

 conclude that these elevated levels of sand have resulted from jt 



cumulative impacts of grazing and logging in the watersheds. The * 



amount of sand in any given reach of stream probably varies 

 annually depending on floods and runoff, but the high levels 

 observed suggest accelerated erosion rates. 



Sequoia National Forest Fails to Analyze Cumulative Effects 



The Sequoia National Forest has devised a procedure that 

 purports to analyze cumulative watershed effects, and which 

 purportedly serves to identify v;atersheds that cannot tolerate 

 further disturbance. Based on four years of studying the 

 procedure's documentation and implementation I conclude that the 

 procedure fails utterly to analyze cumulative watershed effects. 

 The procedure relies on untested, scientifically unsound 

 assumptions and Olympian logical leaps. The "analyses" presented 

 in cumulative watershed assessments by the Sequoia National 

 Forest would not constitute passing work if submitted to me in a 

 university-level course. This is because the documents reflect 

 neither a sound understanding of geomorphic and hydrologic 

 processes, nor clear, logical reasoning. 



As I have continued to study the "analyses" performed by the 



I 

 I 



