GROUND WATER QUALITY 



Introduction 



Ground water is used extensively in the Clark Fork 

 Basin, primarily for domestic purposes, irrigation, live- 

 stock, and industry. It also supplies base flow to the Clark 

 Fork and its tributaries. Although the ground water resource 

 has not been studied as intensively as the surface water 

 system, a fair amount of ground water data exists for 

 portions of the basin. The headwaters. Deer Lodge Valley, 

 and Milltown-Missoula areas have been characterized in some 

 detail. However, very little if any work has been done to 

 describe the ground water system between Garrison and 

 Milltown and in the basin below Missoula. This section of 

 the report describes ground water quality in the Clark Fork 

 Basin. The discussion focuses primarily on recent investiga- 

 tions (1983 or later) , although it addresses historical 

 studies briefly. 



Historical Ground Water Quality Studies 



The earliest investigator to describe the ground water 

 resources of the Butte area was probably Meinzer (1914) , who 

 studied the alluvial aquifer in the Blacktail Creek Valley. 

 Botz (1969) also examined ground water quality and hydraulic 

 characteristics in the Blacktail Creek alluvium, which is the 

 principal aquifer in the upper Silver Bow Creek Basin. Botz 

 described the aquifer as relatively thick with a large 

 quantity of water stored in the interlayered fine gravels, 

 sand, and silty and clayey sand. He reported that ground 

 water quality was generally good except along Silver Bow 

 Creek, where the flow of poor quality surface water to the 

 ground water system resulted in degradation of the aquifer. 



A number of studies were also conducted to evaluate the 

 ground water system near the Berkeley Pit and AMC's former 

 Butte operations, including: Stout (1961) , Botz and Knudson 

 (1970), and Hydrometrics (1980). 



Konizeski et al. (1968) conducted an in-depth study of 

 the geology and ground water resources of the Deer Lodge 

 Valley, from the headwaters to Garrison. However, the study 

 was primarily a physical characterization of the valley 

 rather than an assessment of ground water quality. Some of 

 these findings were discussed briefly in Chapter 1. 



Boettcher and Gosling (1977) described the water 

 resources of the Clark Fork Basin upstream from St. Regis. 

 Their report included general information on the quality 

 (common constituents) and availability of ground water, 



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