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Maribyrnong Catchment

Land Use

Urban

Rural

Forest

Water Quality Index

Very Good

Good

Fair

Poor

Very Poor

See the ‘Maribyrnong Catchment’ page for a detailed description of the catchment.

Report Card for July 2012 – June 2013

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.

Area Score
2%

Very Good
Near-natural high quality waterways

Barringo Creek at Wooling Road, Macedon

0%

Good
Meets Victorian water quality standards

Forested upper catchment

84%

Fair
Some evidence of stress

Mostly in the upper and mid-catchment

12%

Poor
Under considerable stress

Medium density urban and suburban sites

2%

Very Poor
Under severe stress

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.

What does this mean?

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.

Events

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.

Bar chart showing WQI and indicator scores for Maribyrnong Catchment Bar chart showing WQI and indicator scores for Maribyrnong Catchment

maribyrnong-maribrynongwithcityscape.jpg Lower Maribyrnong River. Source: Melbourne Water

BrimbankparkrecreationalactivitiesParksVic.jpg Brimbank Park. Source: Parks Victoria

Changes over time

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.

Plot of WQI history for Maribyrnong Catchment Plot of WQI history for Maribyrnong Catchment

Actions

What's happened?

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:

  • Partnership projects with local councils to build wetlands, raingardens and swales to treat stormwater runoff and remove pollutants that would otherwise end up in rivers and creeks - including Broadmeadows Town Park stormwater harvesting.
  • Melbourne Water maintenance works on waterways, which included 333 km of weed control, 8.13 km of revegetation and the removal of 1,700 cubic metres of litter and debris.
  • Working with rural landholders to reduce the amount of soils and sediments - particularly nitrogen and phosphorus - ultimately entering the Maribyrnong River via runoff from their properties. This program resulted in an annual reduction of 69 kg of sediment, 2192 kg of nitrogen and 786 kg of phosphorus in local waterways.

For more information about projects and works in the Maribyrnong catchment in 2012-13, please see the Waterways Local Updates.

What's planned

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:

  • Management of urban runoff through improved sediment management on building and roads sites.
  • Working with landowners to continue the implementation of on-farm practices and on-ground works to reduce pollutants and runoff into waterways, minimise farm dam impacts on streamflows and to remove stock access to waterways.
  • Updated guidance for onsite wastewater management to reduce the impacts of stormwater pollutants and flows.
  • EPA hotspots investigations into high-risk waterways.

For more information on actions planned for the Maribyrnong catchment to improve the health of rivers and creeks, please see the Healthy Waterways Strategy.

Compare to other Catchments

The following figures show a comparison of scores for each identified water quality indicator in the catchments and Port Phillip Bay.

Diagram of nutrient score history for catchments and bay

Diagram of oxygen score history for catchments and bay

Diagram of water clarity score history for catchments and bay

Diagram of salinity score history for catchments and bay

Diagram of score history for catchments and bay

Diagram of metals score history for catchments and bay

Program Partners

Department of Environment and Primary Industries Environmental Protection Agency Melbourne Water