The reservations are needed to maintain fish habitat, 

 aquatic insect populations, and other aquatic plant and 

 animal life that sustain fish. Channel configuration in 

 conjunction with flow provides the only living space 

 available to aquatic organisms in streams. Adequate 

 streamflows are necessary for maintaining spawning and 

 rearing areas, providing suitable shelter, and producing food 

 organisms, including aquatic macroinvertebrates and forage 

 fish. In an aquatic ecosystem, water quantity is as critical 

 a component of fish habitat as is water quality. 



Water Quality Benefits 



Surface water in the upper Clark Fork suffers from 

 dramatic water pollution problems. The most serious problems 

 are the result of decades of mining and smelting activities 

 in the headwaters. There are massive deposits of mine 

 tailings in the Butte area, along Silver Bow Creek, and at 

 the sites of the Anaconda Smelter and Opportunity Pond 

 system. Runoff entering Silver Bow Creek from these areas is 

 acidic and has high concentrations of metals. Silver Bow 

 Creek is treated with lime at the Warm Springs Ponds on a 

 seasonal or streamflow basis to raise the pH and precipitate 

 the metals that are in solution. 



In addition to mine tailings in the Butte-Anaconda area, 

 there are substantial deposits of mine tailings in the 

 riparian zone and floodplain of the upper Clark Fork itself. 

 These deposits are chronic sources of metal contamination to 

 the upper Clark Fork and they may contribute acutely toxic 

 concentrations of metals during periods of precipitation and 

 runoff. 



There are several reasons why water pollution in the 

 Clark Fork is related to flows: 1) high streamflows greatly 

 increase metal concentrations by eroding mine tailings that 

 have been deposited in the floodplain. Some of the highest 

 metal concentrations in the Clark Fork occur during spring 

 runoff; 2) flows in Silver Bow Creek that exceed the capacity 

 of the Warm Springs Ponds are bypassed directly into the 

 upper Clark Fork; and 3) low-flow conditions can aggravate 

 water quality problems by reducing the amount of water 

 available for dilution of industrial and municipal discharges 

 and nonpoint pollution. Montana law does not recognize 

 dilution of wastewater as a beneficial use of water. As new 

 provisional water use permits are issued in the basin, 

 individuals holding wastewater discharge permits may be 

 affected but they do not have a legal basis for objecting to 

 the new permit applications. Current and future industrial 

 and municipal waste discharge permits could be affected by 

 chronic low-flow conditions, i.e., the allowable amount of 



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