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 2. Red Rock River Drainage 



The Red Rock River drainage contains approximately 1,600 square miles in 

 extreme southwestern Montana. The watershed is defined by the Beaverhead 

 Mountains to the west, the Centennial Mountains to the south, and the 

 Gravelly Range to the east. Clark Canyon dam marks the mouth of the 

 drainage. The DNR&C drainage basin designation is 41A, and the DHES has 

 classed all streams as B-Dj. 



The Centennial Valley contains some of the better timber in the Dillon area; 

 however, site factors (steep slopes, soil conditions) may limit its 

 economic merchantability. 



Forestland ownership within the Red Rock River drainage is predominantly 

 USPS and BLM, with lesser amounts of state and private ownership. Although 

 USPS ownership is well consolidated, some areas have significant mixed 

 ownership patterns amongst several landowners. Harvest activities not 

 coordinated between various land ownerships increases the potential for 

 water quality impacts; this is of particular importance in the Medicine 

 Lodge Creek watershed. Problems are shown in Table VI-C2 and on Plate I. 



The physical characteristics of the land are especially susceptible 

 to impacts from silvicultural activities. Several soil groups within 

 the drainage are highly erosive, particularly those associated with fine- 

 grained volcanic materials, loosely consolidated sandstones and shales, 

 or unconsolidated sands and gravels. 



The Red Rock and Horse Prairie Conservation District estimated that 

 nearly 25 percent of the watershed's commercial forestland contribute 

 to non-point source sediment pollution (1977). Site planning is of 

 extreme importance in such environments; preclusion of conventional 

 logging may be necessary in some areas. 



