all the observed instantaneous concentrations, remained woll below 

 the proposed objective of 1 000 mg/L. 



Boron 



The proposed short-term objective for boron is 3.5 mg/L. Figure 3 

 shows the 3-month moving flow-weighted concentrations for boron. 

 There were no exceedances over the period of record (1975 to 1984). 

 The maximum 3-month, flow-weighted concentration for boron during 

 the 1984 irrigation period calculated from the regression equation 

 was 1.79 mg/L. Using the instantaneous data set a maximum boron 

 concentration was calculated to be 1.86 mg/L. 



Boron concentrations used in the flow-weighting computation were cal- 

 culated from daily specific conductance values, using the regression 

 equation: 



B = (0.00149 X specific conductance) -0.31 (R^ = 0.79) 



The trend in each annual curve is similar. As autumn approaches, the 

 3-month, flow-weighted concentrations rise gradually as the ground 

 water contribution accounts for a greater percentage of the stream- 

 flow. In 1984, however, the dip in concentration during spring run- 

 off is less pronounced than in most previous years, probably owing 

 to a comparatively small amount of spring runoff. 



The long-terra, 5-year moving flow-weighted mean concentration is pre- 

 sented in Figure 3. Each point is plotted at the midpoint of a 5- 

 year period, advancing 1 month at a time through the data set. Al- 

 though only the irrigation season (March to October) was of concern 

 to the IJC, all yearly values are included in Figure 3, to better 



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