23 



decreasing trend in piezometric levels matching decreasing reservoir levels. This new infonnation 



would suggest that the ground-water mound in the unoxidized till is not general but likely occurs in 

 unconnected pockets. A review of boron and chloride concentrations does not show any strong 

 trends. 



The piezometric surface of the Empress gravels indicate a regional flow from northwest to southeast 

 below Morrison Dam. Since 1983, the closer an Empress piezometer is to the reservoir, the larger 

 the decrease in water level. Around the lagoon area there is a noticeable drop in piezometric level at 

 the north end of Ash Lagoons No. 1 and No. 2, and a mound has developed at the east end of Ash 

 Lagoon No. 3 North. The mound on the east side of Ash Lagoon No. 3 North is likely due to upper 

 horizon influences. Results for the Empress gravel do not indicate any seepage activity with the 

 majority of piezometer wells showing little change in boron or chloride concentrations. 



Piezometer series C775 is located at the southeast corner of Ash Lagoon No. 3 North. Until 1992, 

 chloride concentrations have only varied in samples from the oxidized-till piezometer C775A. For the 

 last two years, water levels in the oxidized-till piezometer C775B, the unoxidized-till piezometer 

 C775C, and the Empress-gravel piezometer C775D have increased. This is especially significant in 

 C775B where the level has increased 6 metres in the last year and boron concentration has 

 increased to 6.6 mg/L in 1992. The changes seen for the piezometers in the area are significant but 

 more data will be needed to reach any firm conclusions. 



Sand-lense piezometers C712B, C766, and C767 are located between the Polishing Pond and the 

 cooling water canal. C767 is located on top of Dyke G. C766 and C712B are located at the top of 

 Dyke G. 



A review of the boron concentrations for samples from C766 shows an increasing trend until October 

 1988 when levels peaked at 12.6 mg/L. Boron concentration decreased to 6.99 mg/L in April 1990, 



