METHODS 



Sampling Stations and Schedule 



Nine stations were sampled from Laurel downstream to Huntley, 

 including the Clarks Fork River and Yegen Drain: 



I. Yellowstone River at Laurel (above Laurel wastewater dis- 

 charge and confluence with the Clarks Fork River). 



II. Clarks Fork River at mouth. 



III. Yellowstone River at Duck Creek Bridge. 



IV. Yellowstone River at South Bridge (Billings). 



V. Yellowstone River below Corette plant. 



VI. Yellowstone River at East Bridge (Billings). 



VII. Yegen Drain at mouth. 



VIII. Yellowstone River below Yegen Drain (above Billings waste- 

 water discharge). 



IX. Yellowstone River near Huntley. 



Periphyton samples and water samples for algal nutrients were 

 collected at these stations on the dates listed in Table I. 

 Table I. Sampling Schedule (All samples taken in 1975 except the 

 nutrient sample at Station V, which was collected in 1974) 



Station and Date 

 I II III IV V VI VII VIII IX 



Nutrient Samples 9/9 9/9 9/9 9/9 7/22 9/9 10/23 10/7 9/9 

 Periphyton Samples 9/9 9/9 9/9 9/9 9/16 9/9 11/1 11/1 9/9 



