| Key indicators |
Indicator compliance |
% compliance |
|
|
0 |
|
|
0 |
|
|
62 |
|
|
0 |
|
|
0 |
| ■ <0.5 × water quality objective |
| ■ 0.5-1.0 × water quality objective |
| ■ 1.0-1.5 × water quality objective |
| ■ ≥1.5 × water quality objective |
|
The Oxley estuary received an “F” in the 2009
Report Card, a drop from a “D” the previous year. Overall the water
quality in Oxley Creek remained poor with the only EHI indicator partly
compliant with QWQ objectives being Chl-a, which
reduced from 94% compliance in 2007/2008 to 62% in 2008/2009. However,
the turbid waters of the estuary likely limit phytoplankton production
relative to the high nutrient concentrations within it.
Turbidity concentrations in the Oxley estuary
were typically elevated in the upper reaches as a result of the runoff
from various sand and gravel extractive industries operating in the
freshwater reaches of the system. This is compounded by the long
residence times for waters in the upper estuary. As with the Brisbane
estuary, median TP concentrations, although still above QWQ guidelines,
were the lowest recorded to date by the EHMP for all except the upper
most reach of the estuary.
Overall, 55% of the riparian habitat on the
Oxley estuary is unmodified with nearly all of that found in the
intertidal zone. The habitat behind the intertidal zone (background) has
been very heavily modified.
Abbreviations glossary |
Indicators and methods
|
