12 



< 



4.5 

 4.0 

 3.5 

 3.0 

 2.5 

 2.0 

 1.5 

 1.0 

 0.5 

 0.0 



-I — ' — I — ' — I — ' — I — ' — I — ' — I — ' — r 



1 — ' — I — ' — I — ' — I — ' — I — ' — I — ' — r 



Short-Term Objective (3.5 mg/L) 



from sample analysis 

 from regression 



I ■ I ■ I ■ I ■ 



1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 



Year 



Figure 3.7 Three-Month Moving, Flow-Weighted Boron Concentration for East 

 Poplar River at International Boundary. 



— \ — I — i — I — I — ' — \ — I — I — ' — I — I — r 

 Long-Term Objective (2.5 mg/L) 



J I I I I 1 L 



1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 



Year 



Figure 3.8 Five-Year Moving, Flow-Weighted Boron Concentration for East 

 Poplar River at International Boundary. 



