33 

 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 about 780 mg/1 to 

 over 1800 mg/1. Since 1993, higher than normal runoff volumes have markedly improved reservoir 

 water quality. Reservoir TDS levels have generally been less than 1000 mg/1 since 1997. The average 

 TDS in Cookson Reservoir in 1999 was 683 mg/1, the lowest it has been in over 10 years. 



3.5 Air Quality 



SaskPower's ambient SO2 monitoring for 1999 recorded no violations of SERM's hourly and 24-hour 

 average standards at 0.17 and 0.06 ppm, respectively. Readings from the ambient sulfur dioxide 

 monitor continue to be infrequent and of insignificant magnitude. The 1999 geometric mean for the 

 high- volume suspended particulate sampler was 1 7.7 [ig/m^ and this is the seventh consecutive year of 

 below average particulate readings. 



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 1 9, 1 999 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 were nearly identical and also 

 compared very well with the theoretical discharge computation of 0. 1 03 mVs for the 90° V-notch weir. 



