Dissolved Oxygen residual, mg I 
treatment (prior to this raw sewage was discharged into the estuary), and in 1981 it was upgraded to 
secondary treatment. 
-'- 1 - 1 - 1 - 1 — in - 1 - 1 - 1 — 
1960 1970 1980 2000 2005 
Year 
Figure 8.2 Interannual trend in residual dissolved oxygen values during 1960 to 1986 for a) Zone 1 
and b) Zone 2. Zone 2 regressions are significant at the p< 0.05 level, while Zone 1 regressions 
are not. The solid and dashed lines represent the significant dry and wet season trends, 
respectively (Mann Kendall, p<0.05). Data from recent years are also shown for comparison, 
but were not included in regression computations. 
55 
< <■ 
