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At location 18 (piezometer C741), situated near the southwest end of 

 Morrison Dam, there are no trends discernible over the past three 

 years. At location 21 (piezometer C742) there are likewise no 

 noteworthy trends in water quality. 



Montana 



Samples collected and analyzed in 1988 show that previous trends are 

 being maintained and no outstanding anomalies have been noted. Data 

 from the initial group of wells that have been sampled since 1980 are 

 internally consistent. The second group of wells, first sampled as a 

 group in 1985, have data which show minor changes. Annual sampling 

 does not constitute substantial development and these minor shifts 

 may simply represent the diminishing construction effects of "delayed 

 equilibration." 



Well 16, reported to be completed in a gravel, has a total depth of 

 85 feet. Analyses of the water from this well have a trend of 

 decreasing hardness, sulfate, and TDS, coupled with a stable sodium 

 concentration and increasing sodium adsorption ratios (SARs) and 

 alkalinity. The low alkaline earth concentration (Ca=13.4 mg/L, 

 Mg=6.5 mg/L) and elevated sodium concentration (220 mg/L) are not 

 typical of the Empress Gravels. The low chloride concentration 

 eliminates upward leakage from the Fox Hills/Hell Creek aquifer as a 

 possible explanation. Thus, the water chemistry is a bit of an 

 enigma. 



