ground-water contribution to streamflow increases. The I982 calendar year 



data are also presented using daily boron concentrations estimated using 



2 

 the regression equation: Boron = 0.001^7 x Conductivity - 0.2538; r = 0.82. 



Based on sample data, the maximum boron concentration during I982 for the 

 irrigation period (March through October) was 2.0 mg/L on March 9th. For 

 comparison, the maximum concentration was 1.93 on March 3 and 19, 1982 using 

 the regression equation. The maximum sample concentration of boron for the 

 entire year was 2.2 mg/L on February 11, I982. 



Total Dissolved Solids 



The long-term five-year moving average for TDS ranged from 529 to 753 mg/L, 

 never exceeding the recommended long-term objective of 1,000 mg/L (Figure 2). 

 The maximum sample concentration (during the irrigation period) during I982 

 was 1,050 mg/L recorded on September 27, whereas the maximum for the entire 

 year was 1,210 mg/L recorded on February 11, I982. 



Based on the available data, the recommended short-term objective of 1,500 mg/L 

 has not been exceeded during 1975 to 1982. The maximum three-month flow-weighted 

 concentrations for the period of record occurred during the period of June to 

 October I98O when a level of 971 mg/L was measured. During the irrigation 

 period of I982, the maximum three-month flow-weighted concentration was 905 

 or 891 mg/L depending on whether the method of computation used sample data or 

 estimated concentrations, respectively. The regression equation for estimating 

 daily total dissolved solids concentrations is: 



TDS = 0.647^ (conductivity) - 4.018; r^ = 0.9^ 



Other Water Quality Characteristics 



With the exception of zinc, the multi-purpose objectives recommended by the 

 IJC International Poplar River Water Quality Board for the East Poplar River 

 near the International Boundary were achieved during I982 (Table 1). The 

 concentration of zinc exceeded the recommended objective of 0.03 mg/L in 

 one of sixteen samples. The mercury content of the river is still uncertain 

 because the two principle data bases do not compare. The Environment Canada 

 data indicated that the mercury content was at or below the analytical 

 detection limit of 0.02 ug/L. The United States Geological Survey data appear 



15. 



