Caboolture Region Water Quality Study - Moreton Bay Regional ...

Pumicestone Passage
5.6 Pumicestone Passage
Overall results of water quality assessments for Pumicestone Passage showed that water quality
deteriorated with increasing distance from the opening of the passage to the ocean (Figure 13). At the
northern end of the passage conductivity, turbidity and secchi depth were variable and at the southern
end, turbidity and secchi depth were variable between sites (Table 16, Figures 14 and 15). Poor water
quality ratings in the central area of the passage were due to high turbidity and poor secchi depth
(Table 16). These patterns probably resulted from water exchange patterns in the Passage, whereby
tidal water drains from approximately one-third the distance from the northern mouth of the Passage.
The patterns of influence of terrestrial run-off in passage water quality are evident in Figures 14, 15).
Concentrations of total phosphorus were good throughout the passage, however total nitrogen
concentrations were high at most sites monitored (Table 16). All of these sites were close to the
entrance of creeks into the passage.
Figure 13. Final water quality assessments for Pumicestone Passage for the year 2000-2001. These ratings represent
assessments based on water quality data for the period October 2000 to September 2001. The dots indicate the latest water
quality assessment in comparison to the Queensland Water Quality Guidelines (green = good, yellow = moderate, red = poor,
grey = insufficient data or median was detection limit which was greater than the guidelines).
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