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Montana 



The Montana groundwater monitoring program consisted of 10 wells (GWQQC 

 2-11) from 1978 until 1984, when 11 additional wells (GWQQC 12-22) were 

 installed. Well 4 was dropped from the schedule in September 1990 when 

 it was found plugged. In 1990, two additional wells were installed to 

 monitor effects of pumping the Empress Gravels for salinity control. 



Hydrographs reflecting water level measurements for selected wells 

 completed in the Hart coal are presented in Figure 33, and measurements 

 along with recorder readings for other wells are presented in Figure 34. 



Hydrographs of selected wells 



19 -x- 17 



2458 



J. 2456 

 1 2454 



>*F> 



Figure 33 . --Hydrographs for selected coal wells 

 completed in Hart Coal Bed. 



Beginning in 1987 and 1988, trends of water-level decline have developed 

 in several wells. Water levels in wells completed in the Hart coal bed 

 have declined approximately 1 foot thus far, the apparent greatest 

 decline (well 6) occurring at the International Boundary south of Cookson 

 Reservoir. Wells 5 and 10, also located at the border and completed in 

 unconsolidated beds, show variable water-levels. The variability is 

 probably attributable to the pumping associated with salinity control 

 pumpage below Cookson Reservoir . 



