28 



3.3.3.2 



Montana 



Samples were collected firom monitoring wells 7, 16, and 24 during 1995. Well 7 is completed 

 in Hart Coal, well 16 is completed in the Fort Union Fonnation, and well 24 is completed in 

 alluvium. No significant changes in water quality was observed. Graphs of total dissolved solids 

 for selected wells are shown in Figure 3. 14. 



1000 



800 



M 600 

 400 



200 



7 



16 



24 



Jan-80 Jan-82 Jan-84 Jan-86 Jan-88 Jan-90 Jan-92 Jan-94 Jarv96 

 DATE 



Figure 3.14 Total Dissolved Solids in Samples frmn Montana Wells. 



1^ Cookson ReseiToir 



3.4.1 Storage 



On January 1, 1995, Cookson Reservoir storage was 29 440 dam', or 63% of the full supply 

 volume. The 1995 maximum, minimum and period elevations and volumes are shown in Table 

 3.4. In addition to runoff, reservoir levels were augmented by groundwater pumping. Wells in 

 the abandoned west block mine site supplied 5 376 dam' to Girard Creek. Approximately 70% 

 of this flow volume reached Cookson Reservoir. Wells in the soil salinity project area supplied 

 1 017 dam' directly to the reservoir. 



