Initiate a monitoring network and a public education 

 program in the Missoula Sole Source Aquifer designated 

 area. 



The Missoula Aquifer was designated as a sole source 

 aquifer in June 1988. The aquifer supplies nearly 100 

 percent of the drinking water for the greater Missoula 

 area. A monitoring network should be established to 

 help track changes in water quality and assist in making 

 informed management decisions. In addition, a public 

 education program should be initiated to encourage 

 responsible use of the ground surface as a means of 

 reducing pollution. 



Fisheries 



The Clark Fork fishery has been seriously damaged by 

 more than a century of water quality degradation and physical 

 habitat alterations. Water pollution abatement in the past 

 two decades has improved the fishery, but game fish are 

 considerably less abundant in the Clark Fork than in other 

 rivers of comparable size. The factors affecting the 

 fishery change as the stream flows from its contaminated 

 headwaters to its confluence with Lake Pend Oreille. Some of 

 these factors are readily recognized, while others are less 

 obvious and require additional investigation. 



The upper river fishery continues to be damaged by the 

 acute and chronic toxicity of heavy metals. Copper concen- 

 trations frequently exceed criteria for the protection of 

 aquatic life at all locations in the upper river. Episodes 

 of acute toxicity, which often occur after thunderstorms, may 

 kill an entire population, but the survival of early life 

 stages of trout is probably most affected by chronic metals 

 pollution. The scarcity of trout in most of the upper river 

 further suggests that reproduction and recruitment are 

 limited. 



Another obvious factor affecting trout production is the 

 seasonal dewatering of the Clark Fork and its tributaries. 

 Dewatering because of irrigation diversions results in 

 diminished fish habitat and marginal water quality condi- 

 tions. Segments of some tributaries are dewatered entirely 

 for short times during some critical water years. 



The effects of other factors on the upper river fishery 

 are less well known. Information is needed on spawning areas 

 and on factors (other than toxicity) that may limit recruit- 

 ment of young fish into the population. Physical habitat 

 degradation has occurred in several areas due to mining waste 

 deposits, stream channelization, and heavy livestock use in 



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