50 miles of the Big Hole and 30 miles of the Beaverhead below 

 Dillon is composed of braided river channels, mature cottonwood 

 forests, numerous islands, wetlands, and backwater channels. 

 Although partially developed, the Big Hole's riparian zone remains 

 highly diverse and excellently preserved, while the Beaverhead has 

 suffered from human impacts. Both rivers, however, provide habitat 

 for osprey, great blue herons, bald eagles, raptors, waterfowl, 

 and river otters. In addition, the steep bordering upland habitat 

 supports golden eagles. An historic peregrine eyrie is located 

 along the Big Hole. 



The tributary basins of the Pioneer Mountains south of the Big 

 Hole also received outstanding species quality ratings. These 

 largely untouched valleys are rich with deer, elk, moose, bear, 

 and pronghorn. A herd of bighorn sheep winter along the lower Big 

 Hole River slopes. The rugged and forested Pioneers support 

 abundant beaver, bobcat, lynx, and marten. 



Ranking only slightly lower in game species value than the 

 Pioneer tributaries, upper Horse Prairie Creek basin also earned 

 an outstanding species rating. This single basin supports 

 outstanding densities of deer, elk, moose, black bear, beaver, 

 bobcat, lynx, and marten. 



Recreation 



The study inventoried the recreational attributes and values 

 of 138 river segments in the Beaverhead/Big Hole drainage--nearly 

 1,800 miles of river, about 14 percent of the 12,528 miles studied 

 statewide. Managers and river users rated 21 percent of the 

 drainage's river miles as Class I (Outstanding), 23 percent as 

 Class II (Substantial), 45 percent as Class III (Moderate) and six 

 percent as Class IV (Limited) (Table 34). 



The drainages contained 29 percent of the Class I and 16 

 percent of the Class II river miles in the state--and only four 

 percent of the Class IV river mileage. Thirteen percent of the 

 state's Unknown value class rivers were in this drainage, showing 

 that more inventory work is needed to better define recreational 

 values. Scenic quality of the mountains and surrounding areas was 

 the most common reason for assigning a value class, comprising 21 

 percent of the reasons listed, followed by good hunting, fishing, 

 and access to wilderness (eight percent each). Reasons for a 

 limited value included the presence of logging and clear cuts and 

 private lands and restricting access. 



Use was heavy on 24 percent of the river miles in the Big Hole 

 and Beaverhead drainages and low on 28 percent. The drainages 

 contained 19 percent of the state's heaviest used rivers and 11 

 percent of the low-use-level segments. Scenic quality was rated as 

 Substantial to Outstanding on 55 percent of this region's river 



84 



