- 24 - 



1300 



1200 

 1100 

 1000 



— 900 



_i 



\ 800 



JL 700 



co 600 



Q 



*~ 500 



400 



300 



200 



100 



-i — | — i — | — i 1 1 1 1 — | 1 — | — i — | — i 1 1 1 — i 1 1 — | — i — | — i — | — I — | 1 — i — i — | — r 



Long-Term Objective (1 000 mg/L) 



' ' i__i i i i i i i i i i i I i i i i i i i 



1 974 1 975 1 976 1 977 1 978 1 979 1 980 1 981 1 982 1 983 1 984 1 985 1 986 1 987 1 988 1 989 1 990 



Year 



Figure 16. — Five-year moving, flow-weighted TDS concentration 

 for East Poplar River at International Boundary. 



The relationship between TDS and specific conductance generated from data 

 collected from 1975 to 1990 is as follows: 



TDS = (0.640 x specific conductance) + 10.701 

 (R 2 =0.87, n=398) 



Boron 



Figure 17 displays monthly boron data collected from Jan. 1981 to Dec. 

 1990 by Environment Canada and the USGS . In Figure 18, individual years 

 are simplified by annual box plots. Within any year, boron displays a 

 marked variability about the median. The lowest boron concentrations 

 occurred in 1982, 1983, and 1986 presumably as a result of high flow 



