This new primary treatment facility was put into 

 operation late in 1972. Although water quality began to 

 improve, it was several years before there were signs of 

 recovery in Silver Bow Creek. Gless (1973) conducted a 

 biological study of Silver Bow Creek from 1972 to 1973 and 

 found almost no invertebrates, which he attributed to a lack 

 of suitable substrate and high heavy metals loads. Anaconda 

 Company's self -monitoring turned up no macroinvertebrates in 

 Silver Bow Creek until 1975 (Chadwick et al. 1986) . Diebold 

 (1974) studied the physical and chemical properties of Silver 

 Bow Creek water and bottom sediments from 1973 to 1974. He 

 performed laboratory leaching studies and concluded that the 

 sediments had a high metal adsorption capacity. 



The primary treatment system was refined in 1974 to 

 increase the holding time prior to discharging wastewater 

 (Chadwick et al. 1986) . A secondary treatment system 

 installed in 1975 further improved water quality, as 

 evidenced by decreased turbidity, TSS, and heavy metals 

 concentrations. By late 1975, a variety of algae and 

 macroinvertebrates were found in Silver Bow Creek (Spindler 

 1976) . 



Although water quality in Silver Bow Creek improved 

 greatly over the days when the stream received untreated 

 wastes, metal concentrations at levels potentially toxic to 

 aquatic life were reported by various investigators (Beuerman 

 and Gleason 1978; Peckham 1979; Botz and Karp 1979; Janik 

 and Melancon 1982; and Hydrometrics 1983a). Most reported 

 increased metals loads between Butte and Gregson that were 

 attributable in part to the large tailings deposits (Colorado 

 Tailings and Ramsay Flats) in the floodplain of Silver Bow 

 Creek. 



Clark Fork 



Spindler (1959) made several observations regarding 

 water quality conditions in the mainstem Clark Fork from his 

 field work conducted in 1957. He found that, based on bottom 

 fauna analysis, polluted water conditions existed in the 

 Clark Fork from Warm Springs to the Bitterroot River. 

 Evidence of conditions approaching gross pollution existed 

 between Warm Springs and the Little Blackfoot River, below 

 Garrison, between Missoula and the Bitterroot River, and 

 below Plains. Among the problems documented were high 

 coliform bacteria concentrations downstream of industrial 

 waste discharges, municipal wastewater, and raw sewage 

 discharges, which rendered the river unsafe for uses other 

 than agricultural and industrial. 



The construction of Warm Springs Pond 3 resulted in 

 improved water quality in the upper Clark Fork. For the 



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