Leachate movement through the ash lagoon liner systems can potentially affect ground-water quality in 

 the vicinity of the ash lagoons. The piezometers listed in the Technical Monitoring Schedules are used 

 to assess leachate movement and calculate seepage rates. Piezometric water level, boron, and chloride 

 are the chosen indicator parameters to assess leachate movement. 



The ground-water monitoring program was expanded in 1994 as a result of Ash Lagoon # 3 South 

 construction. In total 20 new pneumatic piezometers and 28 new standpipe piezometers were 

 completed within their target zones. Testing of these piezometers began in 1995. The limited data so 

 far does not show any unusual or unexpected values. 



Due to the sampling reduction approved by Sask Environment in late 2003 there are some piezometers 

 that are no longer monitored. Of the piezometers previously referenced in this report piezometers 

 C867A, C868A, C871A, C886A, C887A, C868B, C869C, C766, and C767 are no longer monitored. 



The chemistry of water immediately above the liner systems is expected to differ from the surface 

 water of the lagoons. Meaningful information is only available from piezometers installed within Ash 

 Lagoon # 1 where ash has been deposited for many years. Future monitoring of all piezometers 

 completed above the lagoon liner systems will continue with the purpose of confirming the boron trend 

 noted above and to improve the understanding of leachate quality and flow from the ash lagoons. 



The piezometric surface measurements for the oxidized till continue to show the presence of a ground- 

 water mound beneath the ash lagoons. The mound extends from the center of the Ash Lagoon # 1 to 

 the southeast side of Ash Lagoon # 2. Isolated ground-water mounds have developed within the area of 

 the oxidized ground-water mound. Piezometers located in the oxidized till suggest limited leachate 

 activity. No seepage activity is evident in the unoxidized till. 



The greatest changes in chloride and boron concentrations within the oxidized till have occurred where 

 piezometric levels have changed the most. Although increasing water levels do not automatically 

 suggest that the water affecting the piezometers is leachate, changing piezometric levels do suggest 

 ground-water movement. On the west side of the Polishing Pond, the boron levels have changed only 



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