The existing water yield in Wallace Creek is relatively low. There is a Class I 

 perennial stream channel located directly below the project area, which is well 

 vegetated and stable. The increase in water year is about 3%, but well below 

 the 15% threshold developed for Wallace Creek. 



3.2.1.4 Sediment Yield Cumulative Effects 



Sediment yields are expected to increase as a result of anticipated post-fire 

 runoff increases and reduced vegetation cover. Hillslope erosion and 

 increased road erosion are expected as water yield increases occur. In most 

 high intensity bum areas, 80 to 100% of the ground cover was consumed. 

 Ground cover is essential in filtering sediment and reducing overall sediment 

 yields. 



Dirty Ike Creek and Donovan Creek 



Existing cumulative impacts to water quality in the affected watershed are 

 associated with increased levels of sediment delivery to the stream channel. 

 Increased levels of sediment delivery have been caused by timber harvest, 

 grazing residential development, existing road systems and stream crossings. 

 Most of the roads in the drainage are in fair to good conditions, with most 

 roads in a suitable location. Direct sediment delivery is isolated to stream 

 crossings that do not meet BMP standards. 



Sediment yields are expected to increaseas a result of the wildfire, but should 

 be minimal as a result of no continuously flowing surface water in the project 

 area. 



Ashby Creek 



Sediment levels are expected to increase as a result of wildfire. However, the 

 burned area is located at the top of the drainage and neither Class II stream 

 channels in the burned area have continuous surface flow to another body of 

 water. 



Wallace Creek 



Most of the roads in the drainage are in fair condition, with some sections of 

 road in the lower watershed, having insufficient drainage or poorly located. 

 The upper portion of the drainage did have high intensity bum severity where 

 most or all of the ground cover was consumed. Sediment levels in the 



Dirty Ike Salvage Environmental Assessment 



3-9 



