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Water

The need to protect and preserve our waterways, including the River Murray, is driving efforts to increase the volume of wastewater and stormwater that is recycled for use in horticulture, recreation, and in residential developments. The volume of recycled water available for irrigating public spaces within the City of Onkaparinga is increasing via Water Proofing the South, a joint project between all spheres of government and the private sector.

While water restrictions have ended, a water conservation ethic remains within the community. It remains a challenge however to ensure a balance between the consumption of water for community needs and providing water for the ecosystems that depend on it.
 

Indicator: Volume of wastewater reuse
City-wide water consumption   
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Data source: SA Water
City of Onkaparinga / TRILITY
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Strategies / Plans: Environment Strategy 2014-19
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Community Plan 2035: Objective 4.1 Valued Natural Resources
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Volume of wastewater reuse

Treated wastewater is reclaimed and used in the City of Onkaparinga to minimise wastewater discharged into the ocean and also to reduce reliance on potable water resources, such as water sourced from the Murray Darling Basin. Wastewater within the city is treated by the South Australian Water Corporation (SA Water) and through the City of Onkaparinga Community Waste Management Schemes in partnership with TRILITY.

There are two SA Water Wastewater Treatment Plants in the City of Onkaparinga, located in Christies Beach and Aldinga and two Community Wastewater Treatment Plants located at Sellicks Beach and Willunga. Water from wastewater treatment plants can be reused in a number of ways including irrigating farmlands, parklands and outdoor sports grounds. Residential uses include watering lawns and gardens, flushing toilets, ornamental water features and washing cars and pets. Recycling water also reduces the discharge of treated water into the Gulf St Vincent.

The Willunga Basin Wastewater Company is the major distributer of treated wastewater that is reused within the region. It takes treated wastewater from both SA Water Wastewater Treatment Plants and the Willunga Wastewater Treatment Plant and pumps it via 120 km of pipeline to more than 140 users, providing water to more than 4000 acres of land within the McLaren Vale region for grape growing, fruit trees, nut crops and flowers.

The amount of treated wastewater that has been reused within the city has been sourced from SA Water (12) and City of Onkaparinga/TRILITY (13). The most recent available data for analysis was for the financial year 2014-15.

Data Analysis

In 2014-15 there was a total of 6.7 gigalitres of treated wastewater reused within the City of Onkaparinga, with 94.5 per cent supplied by SA Water Wastewater Treatment Plants and 5.5 per cent by City of Onkaparinga Community Wastewater Treatment Plants (Figure 1). 

 

Figure 1: Volume of treated wastewater reused, City of Onkaparinga, 2007-08 to 2014-15

CWM-water-Volume-of-treated-wastewater-reused

Source: SA Water (12) and City of Onkaparinga/TRILITY (13)

 

Trend Analysis

CWM water-volume wastewater reuse trend analysis

There has been a 51.7 per cent increase in the total amount of treated wastewater reused between 2007-08 and 2014-15 (Figure 1). Treated wastewater produced by SA Water between 2007-08 and 2014-15 increased by 54.9 per cent, and there was an increase of 11.3 per cent for the City of Onkaparinga Wastewater Treatment Plants. Please note that the volume of wastewater treated at the City of Onkaparinga Sellicks Beach Wastewater Treatment Plant was only able to be provided for the years 2013-14 and 2014-15, however considering this Wastewater Treatment Plant only contributes an average of less than 0.6 per cent of the total volume of treated wastewater this would have very little effect on the trend analysis comparisons between 2007-08 and 2014-15.
 

Policy Implications

There has been a large increase in the amount of treated wastewater reused within the City of Onkaparinga, which contributes to providing a constant and reliable source of water for agricultural irrigation reducing the need to extract water from environmental sources and furthermore it reduces water discharge into the environment. As outlined in the Environment Strategy 2014-19 the City of Onkaparinga will continue to provide leadership by demonstrating best practice in water conservation by maximising the reuse of wastewater, protection of water quality and ecosystem health and by promoting innovative and integrated water management solutions that help meet relevant water resource targets.
 

City-wide water consumption

The City of Onkaparinga needs to ensure that water is used efficiently to reduce our reliance of water sourced from the River Murray. Water for our consumption is captured and stored in reservoirs, with supply augmented by River Murray water, with treatment of this water occurring before it is distributed to users through the SA Water mains water system. SA Water monitors consumption of water by different users, including residential, non-residential and commercial. Water consumption data was sourced from SA Water and the most recent data available for analysis was for the financial year 2014-15 (12).

Data Analysis

In 2014-15 the total amount of water consumption within the City of Onkaparinga was 14.9 gigalitres. Of this consumption, 83.5 per cent was consumed for residential purposes, 12.7 per cent for non-residential purposes and 3.8 per cent for commercial purposes (Figure 2).

 

Figure 2: Annual residential, non-residential and commercial water consumption, City of Onkaparinga, 2007-08 to 2014-15

CWM-water-annual-water-consumption
Source: SA Water (12)


Trend Analysis

CWM water-city-wide water consumption

There has been an 8.4 per cent reduction in total water consumption between 2007-08 and 2014-15 (Figure 2). While the total amount of water consumption in 2014-15 decreased when compared with 2007-08, the proportion of water consumed for residential purposes had actually increased by 6 per cent. Non-residential water consumption decreased by 6 per cent, with no change in the amount of water consumed for commercial purposes between 2007-08 and 2014-15.

Policy Implications

As outlined in the Environment Strategy 2014-19, the City of Onkaparinga will continue to promote previously introduced water saving initiatives and incentives to ensure water consumption continues to decrease. Furthermore, we will continue to work towards reducing our reliance on water sourced from the River Murray by demonstrating best practice in water conservation through maximising the reuse of wastewater, protection of water quality and ecosystem health and by promoting innovative and integrated water management solutions that help meet relevant water resource targets.

The City of Onkaparinga will also be working towards attracting new investment to the region for further water technology development opportunities. The implementation of these initiatives will continue to achieve Community Plan Objective 4.1 Valued Natural Resources.

 

 

This indicator is linked to other strategies, plans and targets outlined below:

Government of South Australia South Australia’s Strategic Plan Targets: 73. Recycled stormwater: South Australia has the system capacity to harvest up to 35GL of stormwater per annum by 2025.
74. Recycled wastewater: South Australia has the system capacity to recycle up the 50GL of wastewater per annum by 2025.  
75. Sustainable water use: South Australia’s water resources are managed within sustainable limits by 2018.
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Other State Strategies • Water for Good: A plan to ensure our water future to 2050
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National Strategies: • National Water Quality Management Strategy
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