directly to the stream. Although. Action Alternative D may have the short-term increases of 

 sedimentation associated with the restoration work, the long-term impacts of not addressing 

 existing sources of sediment delivery is a risk to the water quality. 



The no action alternative poses the highest risk of additional cumulative watershed impact 

 occurring within the proposed sale area. The predicted long-term impacts to water quality 

 are highest under this alternative because watershed improvement designed to rehabilitate or 

 mitigate existing sources of sediment would not be implemented under no action alternative. 



Cold Water Fisheries (Bull Trout and Westslope Cutthroat Trout) 



The primary concern regarding the proposed action alternatives is the potential detrimental 

 effects of increased sediment delivery to fish bearing streams. Elevated levels of sediment 

 delivery and deposition in streams can pose risk to both bull trout and westslope cutthroat trout. 

 Increased sedimentation in streams can affect trout populations in several ways. Direct impacts 

 to trout usually occur during the early portion of the life cycle, incubating eggs or alevins. The 

 most common direct effect of sediment upon trout populations occurs during egg incubation and 

 fry emergence. Elevated levels of fine sediment (<6.4 mm) in spawning gravel can lead to a 

 reduction in survival (Rieman and Mclntyre 1993). This can occur when sediment actually 

 surrounds the egg and prevents the exchange of oxygen. Sediment deposited on the surface of 

 the streambed may entrap alevins and fry and prevent emergence. 



Increased sediment delivery to streams can indirectly affect fish populations by altering fish 

 habitat. High levels of sediment deposition can cause increased width/depth ratios, and pool 

 filling, which results in a loss of habitat complexity. The filling of the spaces between cobbles in 

 the stream substrate and of pool habitat can decrease hiding cover for juvenile fish and increase 

 predation upon them. 



Impacts to fish habitat can also occur through cumulative watershed effects. Extensive levels of 

 timber harvest in a watershed can contribute to increased intensity and duration of peak flows. 

 This can lead to decreased channel stability by increasing stream bank and channel erosion. 



The potenfial effects of the activities proposed in each of the action alternatives on bull trout 

 populations within the project area were evaluated using the diagnostic /pathways indicators 

 contained in the baseline conditions assessment completed for bull trout in the Upper Willow 

 Creek drainage by the Deerlodge National Forest (see following summary table). 



81 



