Yarra
& Bay

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Yarra Catchment

Land Use

Urban

Rural

Forest

Water Quality Index

Very Good

Good

Fair

Poor

Very Poor

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

Report Card for July 2014 – June 2015

The Report Card provides an overview of water quality in the Yarra 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.

Overall, water quality in the Yarra catchment in 2014–2015 was generally ‘Fair’.

Summary Table: The table below shows the percentage of Yarra catchment that falls into each scoring category. See scoring method for more information.

Area Score
3%

Very Good
Near-natural high quality waterways

Typically forested areas in the upper catchment

30%

Good
Meets Victorian water quality standards

Typically rural areas on the urban fringe in the mid-catchment

17%

Fair
Some evidence of stress

Mostly the Yarra River in the mid-catchment

8%

Poor
Under considerable stress

Mostly the Yarra River in the lower urbanised catchment

41%

Very Poor
Under severe stress

Mostly small tributaries in the lower urbanised catchment

The routine monitoring across 47 sites gives information about 97 per cent of the catchment. The remaining three per cent of the catchment was not included due to the drying of waterways in the catchment or unsafe site access. It is expected that the return of water to these streams will result in a slight improvement to the overall catchment rating.

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

The section 'Changes over time' compares these annual index scores and indicators with Yarra catchment’s scores from previous Report Cards (since 2000). Reults can also be compared to other catchments.

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

What does this mean?

Overall, water quality in the Yarra catchment is generally ‘Fair’.

There is a clear pattern throughout the catchment, where the water quality scores reflect the impacts of various land uses. Sites in forested parks in the upper catchment are protected from development and achieved ‘Very Good’ and ‘Good’ scores (such as the O’Shannassy River).

Rural sites in the middle of the catchment typically range from ‘Good’ to ‘Poor’. In these rural locations, nutrients and sediments enter waterways though runoff from farmland and when stock damage creeks and river banks.

Water quality declines as waters flow from the rural middle catchment and pass through more developed or urbanised areas in the lower catchment.

In these urban areas, ‘Very Poor’ water quality scores result from inputs of nutrients and pollutants in runoff from residential, commercial and industrial areas, roads and other hard surfaces, particularly in the smaller tributaries. Due to its size, the Yarra is somewhat protected from these impacts although at the inner suburb of Kew, the Yarra River water quality was ‘Poor’ as a result of inputs from these lower catchment.

Events

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 can wash sediments, nutrients and pollutants into waterways.

Below average rainfall was observed in 2014–15. The Bureau of Meteorology (BoM – 2016) noted just three events during the year when significant rainfall (22mm–43mm) was recorded.

Three environmental flows with a total of 29,251 million litres of water were released from storages in the catchment throughout the year. One release aimed to improve water quality, support native vegetation and maintain habitat for aquatic species. Two releases were to stimulate breeding and migration in native fish, the Macquarie Perch and Australian Grayling, in the Yarra River.

Bar chart of WQI and parameter scores for Yarra Catchment. Bar chart of WQI and parameter scores for Yarra Catchment.

Raingarden in the Yarra catchment. Source: Melbourne Water Raingarden in the Yarra catchment. Source: Melbourne Water

Changes over time

Generally, the Yarra catchment's water quality has improved since 2000 and despite increased pressure from continued urbanisation and population growth, it has demonstrated an overall improvement over the past 15 years though there has, been a slight decline in water quality over the last 12 months.

This overall improvement is a positive measure in light of the many urban pressures experienced in the lower and middle Yarra catchments.

During times of low rainfall, water quality generally improved, and during years of above-average rainfalls, water quality usually declined. The most recent example of this was the drought-breaking rainfalls in 2010 and the well above-average rainfall in 2011, although the changes in overall water quality for the whole catchment were slight. Average conditions returned over the next three years, resulting in improvements to water quality up to 2013–14.

In 2014–15, there has been a slight decline in water quality from the previous assessment in 2013–14. The continued dry conditions over the last year led to significantly reduced river flows in many of the smaller tributaries entering the Yarra River. In some cases, streams became isolated pools while others dried up completely.

Plot of WQI history for Yarra Catchment Plot of WQI history for Yarra Catchment

Actions

What's happened?

Government agencies, local councils and the community have implemented the following initiatives to improve waterway health in the Yarra catchment:

  • Victorian Environmental Water Holder issued a seasonal watering statement authorising Melbourne Water to 29,251 million litres for environmental purposes in the Yarra River. Melbourne water released three environmental flows into the Yarra River system to improve water quality, maintain habitat for aquatic species and to stimulate breeding and migration in native fish.

Melbourne Water

  • Planted 61 kilometres of native vegetation, maintained 825 kilometres of native vegetation and installed 11 kilometres of stock-exclusion fencing.
  • Removed 3000 cubic metres of silt and sediment, and removed 690 cubic metres of litter and debris from waterways that were affecting basins in the Yarra catchment.
  • Conducted weekly monitoring at four sites to better understand recreational health risks and help identify any pollution sources during the summer period
  • 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.
  • Worked in partnership with rural landholders to reduce the amount of sediment and nutrients entering waterways from agricultural land.

Environment Protection Authority Victoria (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.
  • Investigated pollution event in Darebin Creek and a blocked-up basin in Merri Creek.

For more information about projects and works in the Yarra catchment in 2014–15, please see the Waterways Local Updates.

What's planned?

A number of priority areas and actions have been identified in the upper, middle and lower Yarra catchments 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