The second objective would be to reduce the amount of streambank erosion occurring in the most 

 sensitive impaired reaches of Big Creel<. The objective would be to have approximately the same 

 amount of streambank erosion occun-ing (for several years running) within the impaired sensitive 

 reaches, as occurs in similar non-impaired reaches upstream and downstream. This objective can be 

 monitored using channel cross-sections and bank erosion profile measurements (using bank erosion pins 

 per Rosgen technique). A successful measure of this target would be that the erosion rate of the 

 monitored impaired reaches is not significantly greater than 125% of the erosion rate of the monitored 

 reference reaches, based on a statistically valid comparison. 



The third objective is to reduce the sediment input from upland and stream channel sources. The 

 measure of the achievement of this objective would be the sucessful revegetation and/or armoring of at 

 least 75% of the identified sediment sources. 



These objectives may need to be reviewed after a few years of monitoring results are accumulated. 

 Fires and other natural events may lead to a longer period of time before all of the above targets can be 

 achieved. Even after the targets are achieved, it is recognized that there may be future periods when 

 natural events lead to conditions where the targets are not satisfied for a limited time period. As long 

 as management activities within the watershed are such that the system can recover back to conditions 

 of full support within the normal time period, the water body would not be considered impaired and in 

 need of TMDL development for sediment related conditions associated with the natural event. 



D.1 Pollutant Reduction 



This portion of the watershed restoration plan is difficult, because with non-point sources it is difficult to 

 model and/or estimate sediment yields or sediment yield reductions. The road reclamation effect on 

 sedimentation reduction was modeled using the WEPP soil erosion model. The pollutant reduction for 

 the other proposed restoration activities are described either qualitatively, or as an estimation of 

 percent reduction from the cun-ent situation, based upon best professional judgement. Table - 6 lists 

 the proposed pollutant reductions and the estimation of effect from those activities. Refer to Figure - 8 

 for a map of the locations of the proposed treatments within Big Creek. 



The proposed watershed restoration activities would reduce significantly the input of suspended 

 sediments from the upland eroding sites (e.g. skid trails, landings). Some reduction of 

 suspended/bedload sediments will occur due to the erosion control/stabilization work on the natural mass 

 failures. However, due to slope steepness and soil conditions portions of the slump scarps cannot be 

 revegetated effectively, and will remain a suspended sediment source. There will be major reductions of 

 suspended sediment input with the additional decomissioning of approximately 76 miles of roads. The 

 waterbarring of these roads effectively ends the suspended sediment input from the road prisms except 

 for very short distance directly adjacent to the stream channel. At the same time, road decomissioning 

 reduces the amount of in-channel erosion due to the increased water flow from ditch-intercepted water. 

 However, there are short-tenn sediment increases associated with road decomissioning during the 

 culvert removal stage, as the fine materials under the culvert is eroded until a gravel pavement is re- 

 established. Overall, the proposed reductions are expected to result in conditions where water quality 

 objectives are met and conditions are significantly better than required to ensure full support of cold water 

 fish and associated aquatic life in Big Creek. 



The Table 6 proposed treatements represent a performance based approach to allocating actions 

 needed to ensure protection of water quality and also ensure full support of beneficial uses within Big 

 Creek. The estimated pollutant reductions in Table 6 represent a method for expressing the Total 

 Maximum Daily Load (TMDL) in terms of anticipated yearly load reductions by treatment category. This 



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