& Bay

 Current Alerts 3 currently active, find out more »

Mornington Catchment

Bay and Catchments

Water quality index
Land Use




Water Quality Index

Very Good




Very Poor

Citizen Science Data

Citizen Science monitoring site

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

Report Card for July 2012 – June 2013

The Report Card for the Mornington catchment 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 (turbidity), dissolved oxygen, salinity (conductivity), pH and metals.

These are sampled monthly across five sites as part of catchment monitoring programs.

The following section ‘Changes over time’ compares these annual index scores and indicators with the catchment's scores from 2000.

Results can also be compared to other catchments in the section below ‘Compared to other catchments’.

Site-specific details about indicators can be found via the site lists or can be accessed directly from the map.

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

Very Good
Near-natural high quality waterways


Meets Victorian water quality standards


Some evidence of stress


Under considerable stress

Small tributaries in the urbanised beach suburbs


Very Poor
Under severe stress

Rural drainage to small tributaries in urbanised beach suburbs

The routine monthly monitoring across five sites accounts for 94 per cent of the catchment. The remaining 6 per cent of unmonitored catchment is urban and typically scores as Poor for this region.

What does this mean?

Urban and industrial inputs from coastal towns contribute to poor scores, especially metals from road and industrial runoff. The sites that are sampled in the Mornington catchment are situated along the coastal edge where the water quality depends on the quality of the runoff from the upper rural areas, as well as contributions from the urban areas along the coast.

Although water quality index scores were generally Poor to Very Poor in the small waterways of the Mornington Peninsula, some of the index's individual components, such as water clarity and pH, were rated Fair to Very Good.

Levels for nutrients, salinity and metals are higher than ideal, and are due to low flows and intensive agriculture within the catchment.

The levels of dissolved oxygen required to support aquatic life are not being achieved in the smaller waterways and may be a consequence of low flows.


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 for the period in this catchment that would have significantly affected water quality.

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

PortPhillipBayEPAVictoria.png Mornington coastline. Source: EPA Victoria

Changes over time

Overall, ‘Very Poor’ to ‘Poor’ water quality has been a consistent trend in the Mornington catchment over the past 13 years.

Improvements in water quality can be difficult to achieve in catchments with heavy urban or agricultural land use where the source of pollutants is diverse and widely spread across the catchment. Therefore, the installation of rainwater tanks, raingardens and roadside swales serve an important role in reducing the transport of these pollutants via stormwater runoff.

The ‘Actions’ section below outlines projects and initiatives that will contribute toward addressing the issues outlined above.

Plot of WQI history for Mornington Catchment Plot of WQI history for Mornington Catchment"


What's happened?

Driven by the key water quality issues identified for the region, major projects were implemented to improve waterway health in the Mornington catchment and included the following initiatives:

  • An EPA and Melbourne Water hotspot investigation to track sources of high zinc in Chinamans Creek, Rosebud resulted in targeted inspections and provision of advice to local businesses in the area.
  • 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 and included: Tanti Creek Retarding Basin and Mornington Wetlands; downpipe diversion trial for Balcombe Estuary catchment, Mouth Martha; water-sensitive urban design options for Mornington and Sunshine Creek, Mount Martha.
  • As part of their waterway maintenance, Melbourne Water planted 14 km of native vegetation, controlled 81 km of weeds along waterways and removed 300 square metres of litter and debris from rivers and creeks in the catchment.
  • An EPA partnership with Frankston City Council and Mornington Peninsula Shire to proactively identify and address high-risk pollution sources that may impact water quality and contribute to algal blooms at these local beaches.

What's planned

Management objectives across the Mornington Catchment over the next 20 years include:

  • Management objectives across the Mornington catchment over the next 20 years include:
  • Improvement of streamside vegetation, aquatic animal diversity and maintenance of amenity around waterways.
  • Floodplain-based refuges for wetland fish will be created and protected to provide more habitat for fish to naturally disperse across during periods of heavy rain.
  • Continuation of work with landowners to implement 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.
  • Continued EPA hotspots investigations into high-risk waterways.

MothersbeachLygbyaAlgalBloomEPAVictoria2.jpg Lyngbya Bloom, Mothers Beach. Source: EPA Victoria

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