South Trees Inlet


South Trees Inlet grading
ZONE 9 South Trees Inlet

This pilot report card will report on a sub -set of indicators for water quality only. The grades for future report cards will also include indicators for sediment quality, habitats, connectivity and fish & crabs indicators.

The water quality score for South Trees Inlet was 0.68 and based on physical, chemical, metal and nutrient related parameters.

Enviromental Health
South Trees Inlet Health chart

Zone 9 South Trees Inlet

(Six monitoring sites)

South Trees Inlet is a tidal inlet bordered on one bank by Queensland Alumina Ltd. alumina refinery. The area between the inlet and the Boyne River includes large areas of salt-flat and mangroves.

Water Quality

Taking all of the measured indicators into account, South Trees Inlet received a score for water quality of 0.68 , which was the fourth highest water quality score for Gladstone Harbour in 2013 -’14 and gave this zone an overall environmental grade of B . South Trees Inlet received very good scores for dissolved oxygen, aluminium and copper, a good score for turbidity and poor scores for nitrogen and phosphorus.

Water Quality: South Trees Inlet
South Trees Inlet Water Quality chart
Why were these indicators measured?

Dissolved oxygen was measured as it is an important indicator of potential problems in aquatic environments. Low levels of dissolved oxygen can occur as the result of high levels of organic matter in the water, and can lead to severe problems including mortality of aquatic organisms (e.g. fish kills).

Turbidity was measured as it is an important indicator of potential problems in aquatic environments. High turbidity can occur due to high levels of sediment or other undissolved solid particles being present in the water. This can reduce light levels reaching the seabed leading to reduced health and photosynthesis, and increased mortality of algae and plants. High turbidity can also damage the gills of many marine animals.

Total Nitrogen & Total Phosphorus were measured as they are good general indicators of water quality. However it is important to understand the processes through which these nutrients enter the environment, and how they are cycled through the environment.

Dissolved aluminium & copper were measured as they are relevant as constituents of effluent that may potentially be released into the harbour. High levels of aluminium and copper in aquatic systems can be toxic for algae, invertebrates, fish and other animals. It has yet to be determined whether aluminium in Gladstone Harbour is anthropogenic or naturally occurring.

These six indicators were measured to assess water quality within Gladstone Harbour to be used in the Pilot Report Card.