34 



3.4.2 Water Quality 



The period from 1987 to 1993 saw very low volumes of surface-water runoff to Cookson Reservoir. 

 Consequently, total dissolved solids (TDS) in the reservoir increased steadily from approximately 780 

 mg/L to over 1,800 mg/L. Since 1993, higher runoff volumes have improved reservoir water quality. 

 Since 1997, the TDS levels in the reservoir have generally remained below 1,000 mg/L. The average 

 TDS level in Cookson Reservoir in 2001 was 762 mg/L, up slightly from 2000 but still well below past 

 levels. 



3.5 Air Quality 



SaskPower's ambient SO2 monitoring for 2001 recorded no values greater than Saskatchewan 

 Environment's one-hour average standard of 0.17 ppm and three values greater than the 24-hour average 

 standard of 0.06 ppm, which occurred consecutively on May 8. Meteorological data shows that the 

 wind on May 8 was strong from the south and southwest, which indicates that the exceedances were not 

 likely caused by plant emissions, rather, they were caused by either monitoring equipment problems or 

 emissions from diesel-powered farm equipment in the immediate area. The ambient SO2 monitor was 

 replaced in January 2001. The 2001 geometric mean for the high- volume suspended-parti culate sampler 

 was 22.0 p,g/m^ and 2001 was the tenth consecutive year of below-average particulate readings. There 

 were two exceedances of the Saskatchewan provincial standard of 120 ng/m"'/24 hours. Both 

 exceedances occurred in May, during spring seeding, and agricultural activities may have been the cause 

 of the high particulate results. Meteorological data supports this condition. 



3.6 Quality Control 



3.6.1 Streamflow 



Current-meter discharge measurements were made at the East Poplar River at International Boundary 

 site on July 16, 2001 by personnel from the U.S. Geological Survey (USGS) and Environment Canada 

 (EC) to confirm streamflow measurement comparability. Data from the two current-meter discharge 

 measurements are shown in Table 3.5. The measured discharges compared well with each other, but 

 varied about +9.0% from the theoretical discharge computation of 0.057 m''/s for the 90° V-notch weir 

 due to poor measuring conditions. 



