31 

 3.4 Cookson Reservoir 



3.4.1 Storage 



On January 1 , 1 999, Cookson Reservoir storage was 37 690 dam^ or 85% of the full supply volume. The 

 1999 maximum, minimum, and period elevations and volumes are shown in Table 3.4. The reservoir 

 filled above its Full Supply Level (FSL) in late March. Inflows into the reservoir maintained levels 

 slightly above FSL throughout the spring and early summer time period. The spring spill from the 

 reservoir was adequate to meet the recommended Polar River basin demand release for the 1998-1999 

 apportionment year. A small release was required from the reservoir during late summer, to help ensure 

 Saskatchewan maintained the flows at the international boundary near the recommended apportionment 

 target flow. 



In addition to runoff, reservoir levels were augmented by ground-water pumping. Wells in the abandoned 

 west block mine site supplied 4,410 dam^ to Girard Creek in 1999. It is estimated that less than 70% 

 of this flow volume reached Cookson Reservoir. Wells in the soil salinity project area supplied 88 1 dam^ 

 in 1999. 



Table 3.4 Cookson Reservoir Storage Statistics for 1999 



