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The 1986 calculated seepage was approximately the same as that cal- 

 culated for 1985. The calculated total seepage is well below the 

 seepage limits (5.0 L/s to Cookson Reservoir and 2.0 L/s to the East 

 Poplar River) proposed in 1979 by the International Poplar River 

 Water Quality Board of the International Joint Commission. The 

 permeability of the Ash Lagoons Nos. 1 and 2 and Polishing Pond 

 liners was calculated and found to be the same order of magnitude (2 

 to 11 X 10"^ cm/s) as originally calculated by T.A. Prickett. 



The advancement of the seepage front towards the reservoir in the 

 oxidized till was calculated to be 6.11 m since the ponds were 

 initially filled, which is an increase of 1.88 m since 1985. The 

 seepage front in the Empress formation was calculated to have 

 advanced 777 m southeast of the lagoons, an increase of 147 m since 

 1985. However, examination of Empress formation and till water 

 chemistry have not shown significant changes attributable to lagoon 

 seepage. Thus, leachate flow into Cookson Reservoir and into the 

 East Poplar River has not been measurable. 



Saskatchewan Environment and Public Safety requires that the Sas- 

 katchewan Power Corporation maintain the stability of the ash lagoon 

 system dykes. In addition to the regular visual inspections, an 

 annual investigation by a geotechnical engineer was conducted in 

 October, 1986. The freeboard requirements were exceeded during a 

 short time in March of 1986 to minimize any ash blowing problems 

 from Ash Lagoon No. 1. This matter has been remedied and satis- 

 factory freeboard maintenance has been subsequently practiced. 



