Total alkalinity levels were often near or below the recommended minimum 

 of 20 mg/1 (USEPA, 1976). In cases where natural concentrations are less 

 than 20 mg/1, it is recommended that they should not be reduced. 



The Mount Haggin streams that originate at lower elevations along the 

 eastern foothills of the Anaconda-Pintlars are marked by intermediate to high 

 levels of dissolved chemical constituents and good water quality. This 

 stream type includes Slaughterhouse, Sevenmile, Sixmile, Oregon, American, 

 California, French and Willow Creeks. Specific conductance and total alkalinity 

 were much higher than in the high elevation streams. Silica composed a 

 relatively low percentage of the dissolved solids and was dominated by calcium 

 in most cases. This elevation in dissolved solids and decrease in the 

 importance of silica is typical of valley or lowland streams in youthful 

 mountain ranges (Reid and Wood, 1976). 



The higher chemical enrichment of these lower elevation streams can be 

 traced to a mixture of geologic formations. The lower drainages are pre- 

 dominated by glacial outwash which contains a mixture of rock types (USPS 

 unpublished data). Glacial outwash weathers easily and can produce large 

 amounts of dissolved solids into streams. Tertiary volcanics. Cretaceous 

 intrusives and Paleozoic sediments are also present and can contribute to 

 the chemical composition of these streams. 



b) Patterns of Concentration 



Concentrations of dissolved solids in natural waters generally tend 

 to increase with decreasing discharge (Hynes, 1970). The major cations, 

 bicarbonate, silica, specific conductance, alkalinity, hardness and pH 

 all followed this pattern at Mount Haggin. This is indicative of relatively 

 constant ground water sources for these components which concentrate with 

 the decreasing dilution factor. 



Sulphate, chloride and fluoride ions did not concentrate as flow decreased 

 in Mount Haggin streams. These anions reached maximum levels at the high flow 

 and generally tended to decrease in concentration with decreasing discharge. 

 This is indicative of more diffuse sources for these ions which could include 

 decomposition of organic materials, precipitation and sorbed surface particles 

 (Hynes 1970, Ruttner 1963). Surface runoff, rather than groundwater is the 

 probable major source of these components in the Mount Haggin streams. 

 Sulphate and chloride were found to increase with decreasing flow in the Big 

 Hole River (Bahls, 1978). 



Nitrate concentrations exhibited still another pattern of concentration 

 in the Mount Haggin streams. The highest concentrations of nitrate were 

 measured at intermediate flow while trace concentrations were found at the 

 low flow sample in most cases. Nitrate usually becomes available to streams 

 via precipitation and decomposition of organic debris (Hynes 1970, Reid and 

 Wood, 1976); The major source, then, is runoff. Nitrates generally reach 

 maximum concentrations during the spring runoff and decrease rapidly as they 

 are taken up by plants as discharge decreases (Reid and Wood, 1976). Bahls 

 (1978) observed maximum nitrate concentrations in June and the lowest 

 concentrations in early July in the Big Hole River. He believed that nitrogen 

 became the limiting factor for priniary production after July. The deviation 

 of the Mount Haggin streams from this pattern may be due to several causes. 



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