See the ‘Maribyrnong Catchment’ page for a detailed description of the catchment.
This Report Card provides an overview of water quality in the Maribyrnong catchment from 1 July 2012 to 30 June 2013. The quality of the water is given an overall score by combining the results of six standard water quality parameters: nutrients, water clarity (turbidity), dissolved oxygen, salinity (conductivity), pH (acidity/alkalinity) and metals.
In 2012-13, water quality in the Maribyrnong catchment was ‘Fair’.
Summary Table: The table below shows area-weighted distribution of site scores based on subcatchments. Scores are averaged in subcatchments with multiple sites. See scoring method for more information.
Barringo Creek at Wooling Road, Macedon
Forested upper catchment
Mostly in the upper and mid-catchment
Medium density urban and suburban sites
Densly populated urban and industrial sites and the lower Maribyrnong River
The routine monthly monitoring across 15 sites accounts for 79% of the catchment. The remaining 21% of unmonitored catchment is mostly rural which typically scores as ‘Fair’ for this region.
The water quality in the Maribyrnong catchment is ‘Fair’. Water quality in the Maribyrnong catchment is closely linked with the impacts of urbanisation, industry and other human activities. The majority of the catchment (84 per cent) is rated as ‘Fair’, which is unsurprising given the majority of the mid to upper catchment is primarily used for agriculture. Runoff from agricultural land can be a major source of sediment and nutrients in rural waterways.
Streams in the upper catchment, such as Barringo Creek, have little impact from urbanisation and industry, that enables a ‘Very Good’ water quality score.
Some streams in the upper reaches of the Maribyrnong catchment, such as Jacksons Creek and Deep Creek, are influenced by agriculture and scored ‘Fair’ to ‘Poor’ water quality.
The Maribyrnong River scored ‘Fair’ and ‘Poor’ through most of its peri urban and urban regions. Smaller waterways in the urban region including Taylors Creek, Steele Creek, and Stony Creek scored ‘Very Poor’ largely as a result of excessive nutrients and heavy metal contamination. Spikes in salinity and low levels of dissolved oxygen in 2012-13 reduced scores at Taylors Creek and may be reflect low stream flow.
The Report Card's water quality index is based on monthly sampling which can mean short-lived environmental and weather events that can impact water quality are not always captured. This section highlights events for the 2012-13 reporting period.
There were no significant environmental or weather events recorded in this catchment during this period that would have significantly affected water quality.
A long-term trend of improvement in the Maribyrnong catchment was amplified by the break of the drought and an increase in the sustained flow in its waterways.
This trend of improvement over time may be due to the relatively low level of urbanisation in this catchment along with improvements in irrigation and agricultural practices over the past decade.
Platypus surveys indicate that juvenile platypus numbers are at their highest in at least five years in Jacksons Creek (a tributary of the Maribyrnong River). The breaking of the drought as well as habitat improvements have encouraged platypus breeding. The ‘Actions’ section below outlines projects and initiatives that will contribute toward addressing the issues outlined above.
Driven by the key water quality issues identified for the region, major projects were implemented to improve waterway health in the Maribyrnong catchment and included the following initiatives:
For more information about projects and works in the Maribyrnong catchment in 2012-13, please see the Waterways Local Updates.
Ongoing management objectives across the Maribyrnong Catchment have been tailored to support the trend of water quality improvement that has been shown in the catchment. Actions and projects include:
For more information on actions planned for the Maribyrnong catchment to improve the health of rivers and creeks, please see the Healthy Waterways Strategy.
The following figures show a comparison of scores for each identified water quality indicator in the catchments and Port Phillip Bay.