SURFACE WATER QUALITY 



East Poplar River at the International Boundary 



The 1981 report by the IJC to Governments recommended: 



For the March to October period, a maximum flow-weighted 

 concentration should not exceed 3.5 mg/L boron and 1500 mg/L for 

 total dissolved solids for any three consecutive months in the East 

 Poplar River at the International Boundary. 



For the March to October period, a long-term average of flow-weighted 



concentrations should be 2.5 mg/L or less for boron, and 1000 mg/L or 



less for total dissolved solids in the East Poplar River at the 

 International Boundary. 



Compliance of the East Poplar River water quality with the proposed 

 short-term objectives for boron and total dissolved solids (TDS) is tested 

 by calculating the 3-month (90-day) moving flow-weighted concentration for 

 each, advancing 1 month at a time while dropping the first month of the 

 three-month period. Prior to 1982, determination of compliance was based 

 strictly on instantaneous samples. Since the beginning of 1982, daily TDS 

 and boron concentrations have been computed from a regression relationship 

 with specific conductance. However, the data from both instantaneous 

 samples and from calculation of TDS and boron are presented. 



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