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 2002 was 910 mg/L, up from the 2001 average level of 762 mg/L 

 but still below past levels. 



3.5 Air Quality 



SaskPower's ambient SO2 monitoring for 2002 recorded no values greater than Saskatchewan 

 Environment's one-hour average standard of 0.17 ppm and the 24-hour average standard of 0.06 ppm. 

 The 2002 geometric mean for the high- volume suspended-particulate sampler was 18.8 |ag/m and 2002 

 was the eleventh consecutive year of below-average paniculate readings. There were no exceedances of 

 the Saskatchewan provincial standard of 120 ug/m /24 hours. 



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 24. 2002 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 and the 

 theoretical discharge computation of 0.047 m /s for the 90" V-notch weir. 



