STUDY NUMBER ; 12.1 (COMPLETED) 



ORGANIZATION : Anaconda Minerals Company/ Chadwick and Associates 



TITLE OF STUDY ; Benthic Invertebrate Studies on the Upper Clark 

 Fork River 



CONTACT ( S ) ; Steve Canton - Chadwick and Associates - (303) 



794-5530 



Loren Bahls - Montana Department of Health and 

 Environmental Sciences, Water Quality Bureau - 

 444-2406 



OBJECTIVE ; Annually monitor the benthic invertebrate communities 

 in Silver Bow Creek, Mill-Willow Creek and the upper Clark Fork 

 River. 



DURATION : 1972 - 1985 



CURRENT STATUS ; Benthic invertebrate samples were collected 

 yearly during autumn at eleven stations. Five of these stations 

 are on Silver Bow Creek (from Butte to Opportunity) two are on 

 the Mill-Willow bypass channel (one above the Warm Springs Ponds 

 and one below the confluence with the Pond 2 discharge) and three 

 are on the Clark Fork River (at Warm Springs, Deer Lodge and 

 Phosphate). Three separate quantitative samples were collected 

 at each station using a modified Hess sampler. Organisms were 

 identified to the lowest practical taxonomic level using available 

 keys. Wet-weight biomass was determined for major groups (i.e., 

 insect orders). Analysis of the invertebrate community includes 

 calculation of the Shannon-Weaver Diversity Index. 



PUBLICATIONS AND REPORTS 



Annual progress reports entitled, "Aquatic Biological Survey 

 of Silver Bow Creek and the Upper Clark Fork River" have been 

 prepared by Chadwick and Associates. 



Canton, Steven and Jcunes W. Chadwick, 1985. The Aquatic Invert- 

 ebrates of the upper Clark Fork River, 1972 - 1984. In Carlson, 

 C. E. and L.L. Bahls (eds.). Proceedings of the Clark Fork Sym- 

 posium, April 19, 1985. Montana College of Mineral Sciences 

 and Technology, Butte, Montana. 



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