Brown trout, rainbow trout, mountain whitefish and an 

 occasional arctic grayling, brook trout and fcutthroat trout 

 comprise the sport fish in reach #1. Other fish present in- 

 clude white sucker, longnose sucker, m.ountain sucker, mottled 

 sculpin, longnose dace, Utah chub, carp and yellow perch. 



Cross-sectional measurements in reach #1 were made in a 

 404-ft subreach located near the mouth of Warm Springs Creek 

 at river mile 30. Five cross-sections were placed within the 

 subreach. The lowermost cross-section was placed in a rela- 

 tively deep constriction and the uppermost in a wide, shallow 

 area containing well defined weed beds (Figures 2, 3 and 4). 



Reach #3 encompasses a 29-mile section of the upper river 

 between McAtee Bridge (river mile 72) and Quake Lake (river 

 mile 101) . The channel averages 223 ft in width. Depths 

 rarely exceed 4 ft. This reach consists of turbulent riffle- 

 run areas interspersed with large boulders. Boulder/ cobble 

 and gravel comprise the bottom substrate. The gradient aver- 

 ages 27 ft per m.ile. The floodplain is vegetated with grasses 

 mixed with willow, alder and an occasional cottonwood and . v -.■> ■ 

 conifer. 



Rainbow trout, brown trout, and mountain whitefish are 

 the dominant sport fish in reach #3. Other fish present in- 

 clude cutthroat trout, arctic grayling, longnose sucker, white 

 sucker, mountain sucker, mottled sculpin and longnose dace. 



Cross-sectional measurements in reach #3 were made in 

 a 323-ft subreach located near the mouth of Squaw Creek at 

 river mile 88. Five cross-sections \-fere. placed in the sub- 

 reach. The lowermost cross-section was placed in a wide 

 riffle area and the uppermost in a narrower run (Figures 

 5 and 6) . 



Beaverhead River 



The Beaverhead River (Figure 7) originates at the out- 

 let of Clark Canyon Reservoir, an irrigation storage facil- 

 ity constructed in 196 4, and flows 80 miles before joining 

 the Big Hole River to form the Jefferson River. It drains 

 an area of about 5,000 square miles. Gradient averages 

 12 ft/mile. Selected chemical and physical properties of 

 the river are given in Table 2. A detailed description of 

 the river and its fishery is given by Nelson (1977) . 



9 



