agitated by hand and a 1.0-liter Imhoff cone sample of water was 

 obtained from inside the corer. After the cone sample settled 

 for twenty minutes, the settled suspended material was read in 

 mg/1. 



Core samples were stored in plastic bags, labeled and 

 transported to the U.S. Forest Service Helena Ranger District 

 lab, where they were sieved and weighed. The sieve series 

 consisted of 50.8, 25.4, 12.4, 9.5, 6.3, 2.36, 0.85, and 0.074 mm 

 sieves. (Table 2). 



Table 2. Substrate particle size classes and ranges (Modified 

 from the Wentworth classification in Welch 1948) . 



Substrate class Particle size range (mm) 



Cobble >50.8 



Gravel 0.85 - 50.8 



Fines 



Sand 0.074 - 0.85 



Silt <0.074 



Physical Measurements 



Current velocities were measured with a Teledyne Gurley 

 Model 622 current meter at 60% of the depth. Discharges (in 

 cubic meters per second) were calculated according to the methods 

 of Armour and Platts (1983) . 



12 



