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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 2014 – June 2015

This Report Card provides an overview of water quality in the Mornington catchment from 1 July 2014 to 30 June 2015. 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 2014–15, 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

Waterways in the rural areas


Under considerable stress


Very Poor
Under severe stress

Rural drainage to small tributaries in urbanised beach suburbs

The routine monitoring at 5 sites gives us information for about 94 per cent of the catchment. The remaining 6 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 these annual index scores and indicators with Mornington catchment’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 that are 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 WQI scores ranged from ‘Poor’ to ‘Very Poor’, in the smaller waterways of the Mornington catchment, some indicators such as water clarity and pH 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 erosion, and agricultural and urban land use that washes sediments, nutrients and pollutants into waterways.

Below average rainfall was observed in 2014–15. The Bureau of Meteorology (BoM – 2016) noted just –one day during the year when significant rainfall (28 mm) was recorded.

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

Bar chart of WQI and parameter scores for Mornington Catchment. Bar chart of WQI and parameter 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 15 years, water quality improved slightly in 2009–10 and in 2012–13. These were both short-lived improvements as the water quality has declined to pre-2009 levels in the last two years.

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 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 and included the following initiatives:

Melbourne Water

  • Planted 7 km of native vegetation and maintained 50 km of native vegetation.
  • Removed 38m3 of silt and sediment, and removed 360m3 of litter and debris from waterways that were affecting basins in the Mornington catchment.
  • Partnered with local councils to construct water-sensitive urban-designed rain gardens, bioswales and other integrated water management projects to capture stormwater for treatment and reuse.
  • Continuation of EstuaryWatch, the citizen-science program to monitor the health of the Balcombe Creek estuary.

Environment Protection Authority (EPA)

  • The $2 million 2014-2017Litter 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:

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