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Report Card 2014–2015

The Yarra River and Port Phillip Bay Report Card was developed to report on the water quality at sites in Port Phillip Bay and its surrounding catchments. Click on the map or list below to explore.

Bay and Catchments

Water quality index
Land Use




Water Quality Index

Very Good




Very Poor

Citizen Science Data

Citizen Science monitoring site

Report Card for July 2014 – June 2015

This Report Card provides a snapshot of water quality in Port Phillip Bay and catchments from 1 July 2014 to 30 June 2015. The quality of the water was given an overall score by combining the results of a number of standard water quality parameters: nutrients, water clarity, dissolved oxygen, salinity, pH, metals and algae.

Overall, water quality in all the river systems and the Bay has marginally declined from the previous assessment in 2013–14, except the Maribyrnong catchment where conditions were maintained. There are differences in condition between the rivers and the Bay.

Summary Table: The table below shows the percentage of the Bay and surrounding catchments that fall into each scoring category. See the scoring method for more information.

Area Score

Very Good
Near-natural high quality waterways

Forested upper catchments and entrance to Port Phillip Bay


Meets Victorian water quality standards

Upper catchments and Port Phillip Bay


Some evidence of stress

Mostly the main rivers and tributaries in the middle catchment areas on the urban fringe


Under considerable stress

Mostly lower reaches of the main rivers and urban tributaries


Very Poor
Under severe stress

Mostly small urban tributaries

In 2014–15, routine monitoring occurred across 105 sites in the Bay and catchments. This represents 83 per cent of the total catchment area. The remaining 17 per cent of the catchments not monitored are mostly rural and would typically score as ‘Fair’.

The section Changes over time compares the 2014–15 Report Card scores and indicators for the catchments and the Bay to the scores from previous Report Cards (since 2000). More detail on the specific catchments and Bay is provided in their individual reports.

Site-specific details within the Bay and each catchment can also be accessed directly from the map or within the individual catchment and Bay reports.

How did rainfall impact on water quality?

See the Water Quality Index section for information on general water quality trends and sources of pollution.

Changes in rainfall can have a big impact on water quality. In 2014–15 rainfall across the region was below the historic average. During winter and spring of 2014 rainfall was approximately 14 per cent and 20 per cent below the average. During summer and autumn of 2015 rainfall was approximately 7 per cent and 19 per cent below the average (Bureau of Meteorology, 2016).

These drier conditions led to significantly reduced river flow. In some cases, this resulted in no water at all, reducing some waterways to isolated pools or dry river beds, particularly in small tributaries. This generally means either there’s no water to sample or that there is a drop in water quality for some parameters. Reduced flow often results in low oxygen levels, increased salinity and algal blooms, all of which can cause stress to aquatic life. For the Werribee and Maribyrnong catchments in their “natural” state these waterways would likely dry out entirely during summer, leaving remnant chains of ponds where ground water meets the surface.

Dry conditions can also result in less stormwater runoff, leading to lower turbidity and nutrient levels in streams. A decrease in these parameters will appear as improvements to the condition of the waterway.


The Report Card's water quality index is based on routine sampling which means the short-lived environmental and weather events that can impact water quality are not always captured. The following events occurred during the 2014–15 reporting period:

  • During September 2014, a storm brought heavy rainfalls to parts of the Melbourne metropolitan region. Flash flooding was reported in some inner northern and eastern suburbs. In November 2014, Melbourne’s CBD recorded its wettest day in 17 months. Other significant rainfalls occurred in October 2014, January, February and May 2015. All of these events had the potential to impact waterways with stormwater runoff from hard surfaces in the city.
  • In early February 2015, a blue-green algae bloom developed in the Werribee River, downstream of the Maltby Bypass, which persisted for several weeks until finally dissipating in mid-May. Blue-green algae occurs naturally in waterways, typically in summer, and can erupt into blooms during hot weather, periods of low flows, or where there is an accumulation of nutrients.
  • Environmental flow releases (controlled releases of water) were delivered in the Werribee, Maribyrnong and Yarra catchments. Key objectives of environmental water releases are to improve water quality; flush out sediment to improve habitat; and to stimulate breeding of fish by providing high water flows at the right time of the year.

These environmental flows were aimed to improve the habitat for aquatic plants, macroinvertebrates, endangered fish, frogs and platypus; and supported the successful spawning of native fish species. The environmental flows also provided water to the Yering Backswamp, a billabong adjacent to the Yarra River near Yarra Glen, which helped it to sustain its regionally important habitat.

Volunteers cleaning up a beach in Port Phillip Bay. Source: Melbourne Water Volunteers cleaning up a beach in Port Phillip Bay. Source: Melbourne Water

Weedy seadragon below Rye Pier. Source: EPA Victoria Weedy seadragon near Rye Pier. Source: EPA Victoria

Changes over Time

The Bureau of Meteorology (BoM) has identified a long-term ‘drying’ trend since the 1970’s in the Melbourne metropolitan region, which shows that annual rainfall is decreasing by 50 mm every 10 years. This is one of the most significant rainfall declines in Victoria.

Since 2000, there has been an overall improvement in water quality in most of the larger catchments and the Bay. In some catchments this may be partially attributed to changes in the monitoring program.

During times of low rainfall, the condition of some streams’ water quality may improve as there is little to no input from urban and rural runoff. This results in lower levels of nutrients and pollutants, and improved water clarity. However, low rainfall for some streams can reduce flows to the point where dissolved oxygen declines to levels that impact the aquatic life in the rivers. In some streams, particularly those in the north-west, salinity naturally increases during times of low rainfall because flow is more dominated by salty groundwater springs.

During times of high rainfall streams are impacted more by increased runoff, which decreases water clarity and increases nutrients and pollutants that enter waterways. The drought breaking rains in 2010 and the well above-average rainfall in 2011 resulted in declines in water quality.

Average conditions over the next three years resulted in improvements in water quality up to 2013–14. In the last year, low rainfall conditions, resulted in the general drying of river catchments. Water quality in all river systems and the Bay has marginally declined, except the Maribyrnong catchment where conditions were maintained.

While climate has shaped much of the water quality condition for the region over this period, the Dandenong and Mornington catchments have consistently shown ‘Poor’ to ‘Very Poor’ water quality over many years. In these catchments, waterways tend to be small or highly modified from their natural state. This makes them more susceptible to the impacts of urban and industrial land use and the pollution that these types of land uses bring.

Plot of WQI score history for all catchments and the bay Plot of WQI score history for all catchments and the bay.


What's happened?

The Government, authorities and community implemented the following initiatives to improve waterway health in the Bay and catchments:

  • The Victorian Government has prioritised the protection and improvement of Victoria's water environments. To ensure Victoria has clear and relevant standards, legal rules and statutory obligations to protect and improve the health of our water environments, the Victorian Government is reviewing two key policies, State Environment Protection Policy (Waters of Victoria) (SEPP (WoV)) including Schedule F6 – Waters of Port Phillip Bay and the State Environment Protection Policy (Groundwaters of Victoria) (SEPP (GoV)).
  • Melbourne Water in 2014-15
    • Removed over 5400 cubic metres of debris, including litter and 11,000 cubic metres of silt from waterways and litter traps.
    • Planted almost 120 kilometres of streamside vegetation across the region.
    • Controlled weeds along 1500 kilometres of waterway.
    • Funded the installation of 63 kilometres of fencing to exclude stock from entering waterways.
    • Removed one fish barrier to improve fish passage.
    • Funded 45 council Integrated Water Management projects totalling $3 million through the Living Rivers Grants.
  • The Communities for Nature Grants Program, which focuses on projects to improve water quality in the Yarra River and Port Phillip Bay.
  • EPA's summer litter campaign ‘A cleaner Victoria is in your hands’ which encourages people to report litter thrown from vehicles via EPA's online reporting tool or mobile apps. It is specifically aimed at creating awareness about the impact of litter on our natural assets such as the Bay and its catchments.
  • The $2 million 2014-2017 Litter Hotspots grants program was introduced by EPA in 2014’. This program is led by the Melbourne Waste and Resource Recovery Group, working with local councils and community groups to find local litter solutions.
  • Improved communication of water quality to the community through the launch of the Yarra & Bay website.
  • The Waterways Ecosystem Research Group at the University of Melbourne, is a group of researchers studying interactions between landscapes and running waters. The group is involved in the development and application of hydrologic, hydraulic and ecological models for achieving healthy streams and rivers in urban and rural landscapes.
  • The Centre for Aquatic Pollution, Identification and Management (CAPIM) is a scientific research organisation, established to identify and address the impact of pollution in water environments. CAPIM's goal is to improve aquatic ecosystem health by developing innovative approaches to pollution detection for inland waters and estuaries, and working with environmental management practitioners to reduce pollution impacts.

For more information on initiatives to improve our waterways in the Port Phillip Bay and catchments in 2014–15 please visit: Waterways Local Updates.

What's planned?

A number of priority areas and actions have been identified for the Bay and catchments that will build on existing projects and initiatives. Priority management actions include:

  • State of the Bays Report – the Commissioner for Environmental Sustainability Victoria will release the first state of the bay report in late 2016. The 2016 State of the Bays Report will be the first of its kind and will provide a scientifically rigorous baseline report on the health of Port Phillip Bay and Western Port against which future reporting can be compared.
  • The Port Phillip Bay Environmental Management Plan is being revised, which includes a focus on better managing pollution coming to the bay (particularly via stormwater) and its impacts on water quality.
  • Melbourne Water's Healthy Waterways Strategy – outlines Melbourne Water's role in managing rivers, estuaries and wetlands in the Port Phillip and Western Port region and identifies actions planned for the future to preserve and protect waterways.
  • Melbourne Water's Stormwater Strategy, which focuses on managing stormwater to protect and improve the health of waterways and bays.
  • Parks Victoria's Marine Natural Values ecosystem condition assessment reporting, which is currently being developed for marine parks across the state, including the four marine-protected areas (Jawbone, Point Cook, Rickett's Point and Port Phillip Heads) in Port Phillip Bay.
  • Roll out of the $2 million 2014-2017 Litter Hotspots grants program. The Litter Innovation Fund, announced in December 2015, provides support for the Victorian community, including government, business, not-for-profit organisations, social enterprises and schools, to fund innovative approaches that prevent and reduce the impact of litter and illegal dumping. A proportion of the Fund has been specifically allocated to support projects that help reduce litter and illegal dumping in the Yarra River and Port Phillip Bay catchment.

Program Partners

Department of Environment and Primary Industries Environmental Protection Agency Melbourne Water