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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 2015 – June 2016

This Report Card provides an overview of water quality in the Mornington catchment from 1 July 2015 to 30 June 2016. 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 2015–16, water quality in the Mornington catchment was ‘Very Poor’.

Summary Table: The table below shows the percentage of the Mornington catchment that falls into each scoring category. 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

Waterways in the rural areas


Very Poor
Under severe stress

Rural drainage to small tributaries in urbanised beach suburbs

The routine monitoring at five sites gives us information for about 94 per cent of the catchment. The remaining six per cent of the unmonitored catchment consists of mostly urban waterways, which would typically score as ‘Very Poor’ for this region.

See the Monitoring Programs page for changes to the monitoring program.

The section 'Changes over time’ compares this year’s annual index scores and indicators with Mornington’s scores from previous Report Cards (since 2000). Results can also be compared to other catchments.

Site-specific details about parameters can be accessed via the map.

What does this mean?

Water quality in the Mornington catchment is ‘Very Poor’.

Water quality in waterways of the Mornington area is influenced by runoff from intensive horticultural and farming activities in the central part of the catchment and polluted runoff from urban coastal towns. Residential and industrial areas also contribute to the poor water quality. Sediment and metals carried in runoff are a particular problem.

Monitoring sites situated along the coast tend to be affected by runoff from the upper rural areas, as well as runoff from urban areas along the coast

Although the individual site scores ranged from ‘Poor’ to ‘Very Poor’, some smaller waterways of the Mornington catchment had indicators, such as water clarity and pH, that were rated ‘Fair’ to ‘Very Good’.


Short-lived environmental and extreme weather events can impact water quality in waterways. Long-term dry spells can result in reduced river flows, increases in salinity and algal blooms, while heavy rainfalls can cause flooding and river bank erosion, and wash sediments, nutrients and pollutants into waterways.

Below average rainfall was observed in 2015–16. The Bureau of Meteorology (2016) noted just one day when significant rainfall (27 mm) was recorded.

Outside of this date, no significant environmental or weather events were recorded for the period that would have significantly affected water quality.

Bar chart of WQI and indicator scores for Mornington Catchment.t Bar chart of WQI and indicator scores for Mornington Catchment.

Balcombe Creek Estuary, Mount Martha. Source: Melbourne Water Balcombe Creek Estuary, Mount Martha. Source: Melbourne Water

Balcombe Creek Estuary, Mount Martha. Source: Melbourne Water Balcombe Creek Estuary, Mount Martha. Source: Melbourne Water

Changes over time

Although ‘Poor’ to ‘Very Poor’ water quality has been a persistent feature in the Mornington catchment over the past 16 years, water quality improved slightly in 2009–10 and in 2012–13. These were both short-lived improvements as water quality declined to pre-2009 levels in the two years that followed. Water quality improved marginally this year, with slightly lower levels of nutrients and improved dissolved oxygen levels.

Improvements in water quality can be difficult to achieve in catchments with heavy urban or agricultural land use, where the source of many pollutants is diverse and widely spread across the catchment. Therefore, the installation of water sensitive urban design features such as rainwater tanks, raingardens and roadside swales (vegetated ditches that collect runoff) play an important role in reducing the transport of these pollutants into waterways.

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


What's happened?

Government agencies, local councils and the community have implemented a range of initiatives to improve waterway health in the Mornington catchment:

Melbourne Water

  • Planted 4 km of native vegetation; maintained 45 km of native vegetation; and installed 2 km of stock-exclusion fencing.
  • Removed 2 cubic metres of silt and sediment, and removed 190 cubic metres of litter and debris from waterways that were affecting basins in the Mornington catchment.
  • Worked with landowners to implement best on-farm practices and on-ground works to reduce pollutants and runoff into waterways; minimise farm dam impacts on stream flows; and remove stock access to waterways.
  • Conducted fortnightly blue-green algae monitoring during the summer period at three sites to manage health risks to people and animals.
  • Conducted weekly monitoring at four sites to better understand recreational health risks and to help identify any pollution sources during the summer period.
  • Continuation of EstuaryWatch, the citizen-science program to monitor the health of the Balcombe Creek estuary.

Environment Protection Authority (EPA)

  • 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.

What's planned

A number of priority areas and actions have been identified in the Mornington catchment to build on existing projects and initiatives. These include:

  • The implementation of Melbourne Water’s ‘Healthy Waterways Strategy’ and ‘Stormwater Strategy'. These two strategies cover the five years from 2013–14 to 2017–18 and contain information about planned actions to improve the health of rivers and creeks in the Maribyrnong catchment.
  • Continuing EPA attendance at pollution events across the catchment.
  • Roll out of the Litter Hotspots grants program.

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