Synopsis

In early 2005 the City of Mitcham received $45,000 as a successful applicant under the demonstration round of the Australian Government’s 'Community Water Fund' program.  Council's project application involved developing an innovative rainwater re-use system to:

• Prevent rainwater from the roof of the soccer and adjacent bowling club from flooding the soccer pitch and training grounds;
• Supply indoor water requirements for water efficient showers, toilets and hand-basins;
• Reduce indoor water requirements by retrofitting water efficient devices;
• Recharge the aquifer to supplement oval irrigation requirements in summer.

The system captures all of the rainfall from both the soccer and bowling clubrooms in two separate 20,000 litre above-ground rainwater tanks.  The tanks are interlinked and a pressure pump supplies the majority of fixtures in the soccer club.  The system is sized to supply the clubrooms for the whole season, with automatic back-up mains supply in dry years.

Savings and Benefits

Water efficiency at the clubrooms has been improved through the installation of auto-off hand-basin taps, low flow showerheads and dual flush cisterns.  Overall, mains water savings in the soccer clubrooms of 275,000 litres are expected.

The rainwater tanks are connected to the aquifer via overflow pipes two-thirds up the tanks.  Rather than wasting space, this provides a buffer during heavy rainstorms, allowing the tanks to gravity feed and recharge the aquifer.  This is expected to save 540,000 litres of bore water which is used for irrigation in warmer months.  As an additional benefit, since rainwater is very low in salinity, the overall quality of the bore water may improve.

Aquifer recharge with clean rainwater is much simpler than many aquifer storage and recovery schemes. As the rainwater is already potable no expensive treatment and ongoing system monitoring are required. This makes recharge accessible for small sites.The system was installed prior to the onset of the heavy winter rains and the soccer club has reported excellent results with little or no overflow from the tanks and no games cancelled due to flooded pitches.

Conservative modelling estimates mains water savings of 275,000 litres per annum and bore water savings of 540,000 litres per annum.

Motivation for Installation of Water Efficiency Measures

City of Mitcham joined the Water Campaign in 2002 and completed their Local Action Plan (LAP) in 2004. The LAP outlined strategies to reduce corporate water consumption by 20%  by 2013 based on 1996/97 levels.

Process

The project links to Council’s strategic plan which states:

2.6.2.1 Identify and implement solutions to conserve and reuse stormwater.

1.4.3 Reduce reliance on mains water for parks and gardens by examining alternative water options such as stormwater reuse, ASR and use of greywater.

Costs

The project was funded by the Australian Government, with Council providing in-kind support and ongoing maintenance.  Project costing breakdown as a percentage of the budget was:

• Irrigation bore modification work - 5%
• Trenching and excavation work - 5%
• Plumbing work - 25%
• Electrical work - 10%
• Materials and appliances - 35%
• Design and project management - 20%

Issues and Lessons Learnt

Council found that it was key to involve representatives from the soccer club, Council's parks and gardens team, and asset managers right from the start of the project.

Acknowledgements

This case study was prepared with assistance from the City of Boroondara and Yarra Valley Water, July 2003.

For further information about this project contact:
Craig Walker
Environmental Planning Officer
City of Mitcham
131 Belair Road
Torrens Park  SA  5062
Tel: 8372 8855
Fax: 8372 8101
Email: cwalker@mitchamcouncil.sa.gov.au

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