10 



The five-year FWC for TDS (Figure 3.5) continued to approach, but remained below the long- 

 term objective of 1000 mg/L. The maximum monthly value calculated in 1996 was slightly over 

 991 mg/L. This is also the highest value for this parameter for the period of record. The gradual 

 increase in five-year FWC for TDS is due to insufficient surface runoff, particularly reflected in 

 the spring flows, which has not allowed for sufficient flushing of Cookson Reservoir. 



The daily TDS values, as generated from the daily specific conductance readings from 1982 to 

 1996 are shown in Figure 3.6. The data show a gradual but discernible increase in TDS over this 

 period. 



The relationship between TDS and conductivity applied to data collected from 1975 to 1996 is 

 as follows: 



TDS = (0.639 X speciric conductance) -I- 11.286 

 (R^ = 0.87, n = 517) 



