20 



DO 



c 

 o 

 s^ 

 o 

 m 



-I — I I I ' — I ' I 



3.0 



2.6 



2.2 



1.8 



1.0 



0.2 ' ' ' ' ' 



Long-Term Objective (2.5 mg/L) 



I . I I I . I 



■ ' ■ I ■ I ■ I 



1974 1976 1978 1980 1982 1984 1986 1988 1990 



1975 1977 1979 1981 1983 1985 1987 1989 1991 



Figure 3.9 Five- Year Moving, Flow Weighted Boron Concentration for East Poplar 

 River at the International Boundary. 



^ 



a 

 o 



Si 



o 



03 



3.5 



3.0 - 



2.5 



2.0 - 



1.5 - 



0.5 - 



0.0 



1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 



Figure 3.10 Sen Slope Estimate for Boron at East Poplar River at the International 

 Boundary. 



