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10. Thompson River Drainage 



The Thompson River drains a portion of the Cabinet Mountains and is 

 tributary to the Clark Fork River about five miles east of Thompson Falls, 

 Montana. It is within the designated basin 76N (DNR&C) with a stream 

 classification of B-Di (DHES). 



Ownership patterns within the drainage are extremely intermingled. Some 

 USFS ownership is consolidated on the east and west sides of the watershed. 

 However, the northern headwaters and central portion of the watershed are 

 administered in a checkerboard fashion under Champion, Burlington Northern, 

 the state, and USFS. 



Timber harvesting and associated road building have been pursued extensively 

 in the Thompson River drainage (USFS and non-USFS lands), resulting in 

 detrimental impacts. The construction of two roads along the river, 

 effectively channelizing the stream, is probably the major impact in 

 the watershed (USFS - Thompson Falls, pers. comm.). The steep terrain 

 of the area contributes to the watershed's sensitivity to silvicultural 

 practices. Problem areas are outlined in Table VI-BIO and located on 

 Plate I. 



Some naturally unstable areas (slumps, slides, etc.) are contributing to 

 high sediment loads in the Thompson River drainage (Honeymoon Creek). 

 Grazing practices also contribute to non-point source water pollution. 



Prevention and mitigation measures must be applied on a basin-wide basis 

 to effectively deal with the identified problems. The most comprehensive 

 measures include: 1) restriction of silvicultural (and other) activities 

 that could further impact existing problem areas; 2) conduct basin-wide 



