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The 1985 calculated seepage was greater than that calculated for the year 

 1984. This has been attributed largely to the loading effects on Ash 

 Lagoon No. 2. 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 were calculated and found to be the 

 same order of magnitude (10-9 cm/s) as originally calculated by 

 T.E.A. Prickett. 



The advancement of the seepage front towards the reservoir in the oxidized 

 till was calculated at 4.23 m since the ponds were initially filled, which 

 is an increase of 1.75 m since 1984. Whereas the seepage front in the 

 Empress formation was calculated to have advanced 628 m southeast of the 

 lagoons, an increase of 144 m since 1984. 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 was zero to date. 



Saskatchewan Environment requires that the Saskatchewan 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 May, 1985. The freeboard requirements were 

 exceeded during a short time in the late spring of 1985 in order to 

 minimize any ash blowing problems from Ash Lagoon No. 1. This matter has 

 been remedied and satisfactory freeboard maintenance has been subsequently 



