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.
The Yarra River and Port Phillip Bay Report Card has generated water quality index scores for the period July 2012 to June 2013. These scores are generated using a combination of standard indicators: nutrients, water clarity, dissolved oxygen, salinity, pH, metals and algae.
The following section ‘Changes over time’ compares these annual scores and indicators from 2000 for the six catchments and the Bay. More detail on the specific catchments or bay is provided in their individual reports.
Site-specific details about indicators can be found via the site lists provided within the individual catchment and Bay reports or can be accessed directly from the map.
Please note that due to improvements in our calculation and quality processes, some sections of this Report Card were updated in 2016 in line with tigher requirements for minimal samples to calaculate the water quality index.
Summary Table: The table below shows the area-weighted distribution of site scores based on subcatchments and marine zones. See the scoring method for more information.
Forested upper catchments and entrance to Port Phillip Bay
Upper catchments and Port Phillip Bay
Mostly the main rivers and tributaries in the middle catchment areas on the urban fringe
Mostly lower reaches of the main rivers and urban tributaries
Mostly small urban tributaries
Routine monthly monitoring across 110 sites accounts for 89 per cent of the Bay and catchments area. The remaining 11 per cent of unmonitored catchments are mostly rural and typically score as Fair for this region.
Port Phillip Bay receives freshwater input from many rivers and drains across the Bellarine, Werribee, Maribyrnong, Yarra, Dandenong and Mornington catchments. Pollutants that accompany these inputs can adversely impact Bay water quality.
Most waterways in upper catchments receive good water quality scores because they are well forested and protected from the impacts of human activity. In the middle catchments area and in some upper catchments, rural land impacts (such as vegetation clearing around waterways, sediment runoff and use of agricultural chemicals) can affect the natural ecology of the waterways.
Water quality in the urban areas of catchments is generally much lower (rated Poor or Very Poor) due to the impacts from residential development and industry. Heavy rains wash litter, pollutants and stormwater into our waterways - which flow downstream and can affect water quality as far away as the Bay. These pollutants reduce the waterway's health and impact species such as fish, platypus, frogs and waterbugs.
Pollutants in urban areas can include: oils and hydrocarbons from vehicles; zinc from tyre rubber; other metals from industrial estates; soil from construction sites; and nutrients from garden fertilisers.
The period July 2012 to June 2013 received below average (18 per cent below average) rainfall, which was most notable during summer (36 per cent below average). (Source: Bureau of Meteorology, Melbourne Regional Office).
The weather was hot and dry over summer with an absence of the tropical storms experienced in previous summers. Such storms can introduce large volumes of water into waterways and can contribute to algal blooms in the Bay. Subsequently, there were few algal blooms in the Bay over the 2012-13 summer period.
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 was a short-lived and localised bloom of the tropical algae Lyngbya at Mothers beach, Mornington, in late summer that was identified as a non-toxic species.
To capitalise on good rainfall in the Yarra catchment an environmental water release was provided down the river over summer and aimed to improve the waterway's health, particularly in the stretch between Yering Gorge and Dights Falls. For more information see the Melbourne Water media release.
Since the 1970s the Bureau of Meteorology has identified a long-term ‘drying’ trend in the Melbourne metropolitan region, which shows that the annual rainfall is decreasing by 50 mm every 10 years. This is one of the largest declines in Victoria.
Over the period covered in this Report Card (2000-13) there has been a recovery from long-term drought (1998-2009) to generally wetter conditions. Increased flows in recent years have improved salinity and dissolved oxygen in the rivers and streams, but have also transported more sediment and nutrients to the Bay.
This climatic backdrop shaped much of the water quality condition for the region over this period, the Dandenong catchment was characterised by poor water quality regardless of climate. In this catchment water quality reflects the impacts of predominately urban and industrial land use.
The ‘Actions’ section below outlines projects and initiatives that will contribute toward addressing the issues outlined above.
Specific Bay and catchments reports provide further details about water quality changes experienced at a local level.
The government, authorities and community work together to protect and improve our waterways and the Bay. Initiatives can range from large capital projects such as building wetlands to smaller projects such as planting streamside vegetation and installing raingardens.
Driven by the key water quality issues identified, major projects were implemented to improve waterway health in the Bay and catchments and included the following initiatives:
For more information on initiatives that are improving our waterways in the Port Phillip Bay and catchments in 2012-13 please visit: Waterways Local Updates 2012-13
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: