BIG HOLE AND BEAVERHEAD RIVER DRAINAGES 



Boundaries: Headwaters to Jefferson River 



Drainage size: 6,381 square miles 



Main stem length: Big Hole 156 miles; Beaverhead 211 miles 



Tributaries: Red Rock River, Horse Prairie Creek, Ruby River 



Cities/Towns: Dillon, Jackson, Lima, Melrose, Twin Bridges, 



Wisdom, Wise River 



Access: Interstate 15; Montana 41, 43 and 278 



The Continental Divide borders the southwest corner of Montana 

 on three sides. In this remote region, eight mountain ranges and 

 the high, windswept, sage-covered valleys separating them collect 

 heavy snowfall, supplying the Big Hole and Beaverhead rivers, 

 which merge at Twin Bridges to become the Jefferson River (Figure 

 6). Elevations vary from the 11,000-foot summits of the Pintlars 

 down to 4,600 feet where the Jefferson is born. The longest 

 continuous water course in the U.S. is said to begin in Hell 

 Roaring Canyon, a tributary of the Red Rock River. 



The Big Hole and Beaverhead rivers share a common destination 

 and some of Montana's best fisheries, wildlife, and recreational 

 values, but there the similarities end. In the Big Hole drainage, 

 sandhill cranes and the rare arctic grayling still find niches, 

 hay is put up using "beaver slides," and cattle outnumber people 

 100 to one. The river's journey to Twin Bridges is uninterrupted 

 by reservoirs and is one of the last major rivers in the country 

 still undammed. By contrast, the Beaverhead River is captured in 

 Clark Canyon Dam near its origin at the confluence of the Red Rock 

 River and Horse Prairie Creek. Highway and railroad crossings 

 contribute to a lack of solitude along the Beaverhead, and 

 irrigation withdrawals on the lower reaches have reduced scenic 

 and fisheries values. 



Fisheries 



A total of 1,423 miles of stream in 190 reaches were assessed 

 in the Big Hole and Beaverhead drainages. Although an additional 

 41 reaches were identified in the fisheries data base, these 

 reaches could not be assessed due to insufficient data. Based on 

 a cursory look through the "Missouri River Mile Index" and 

 discussions with area biologists, only a fraction of the streams 

 in these two drainages have been entered in the data base. Of 

 the stream reaches rated, 71 miles were rated a Class I for their 

 sport fisheries value and 93 miles received a Class II (Tables 31 

 and 32). Included in the Class I reaches were the lower 89 miles 

 of the Big Hole River from Wise River to the mouth and the upper 

 12 miles of the Beaverhead from the dam to Grasshopper Creek. 

 Portions of the Red Rock and the Ruby and additional reaches of 

 the Big Hole and Beaverhead received Class II sport fishery 

 values. The lower 36 miles of the Beaverhead received a Class III 



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