Since the Millennium Drought, Australia's worst in100 years, rainwater tank numbers have surged in urban SEQ. In 2010, about 236,000 rainwater tanks had been installed at existing households. Additional tanks had also been installed in new developments to achieve the 70 kL/household/year (kL/hh/yr) target mandated in the SEQ Water Strategy. Local, or "off-grid", supplies including tanks are anticipated to provide 35 GL of supply by 2026, and 60 GL by 2056. There is great diversity regarding how rainwater tanks have been configured to supply various end-use demands such as internal versus external uses. There are also diverse issues associated with their management and maintenance. Validating how these systems are performing is a new challenge.
The main aim of this project was to understand the effectiveness of achieving the 70 kL/hh/yr targeted water saving, through monitoring, validation and modelling. The project sought to investigate the impact of using rainwater tank water in specific ways guided by the following questions:
- What are the pathogen risks of using rainwater?
- What is the effect of connecting rainwater tanks to hot water systems?
- What is the rainwater use and energy footprint of rainwater tanks?
- What are the optimal design configurations for rainwater tank systems?
- What factors influence acceptance and adoption of rainwater?
- What are the possible governance and management models for rainwater tanks?
- What is the efficiency of communal rainwater tanks in residential and commercial settings?
- What is the energy use and ghg emissions of decentralised wastewater treatment plants?
Key Publications and Outputs
Publications produced are available from the Urban Water Security Research Alliance website including:
- Technical Reports 12, 13, 26, 48, 49, 50, 63, 64, 65, 66, 67, 68, 70, 75, 89 and 105
- Conference papers listed on the Alliance website
- Proceedings of the Alliance Science Forums
- Factsheet 1: Rainwater tanks in SEQ
Mankad, A., Chong, M.N., Gardner, T., and Sharma A.(2012) Examining biophysical and socio-demographic factors across mandated tank users in urban Australia: A linking step towards achieving best practices, Water Resources Management, DOI 10.1007/s11269-012-0003-7
Sharma, A., Burn, S., Gardner, T. and Gregory, A. (2010) Role of decentralized system in the transition of urban water systems" Water Science and Technology: Water Supply, 10(4), 577-583.
Chong, M.N., Sharma, A.K., Saint, C.P. and Burn, S. (2012) Advanced Oxidation Technologies for Wastewater Treatment and Reuse - Where to from here for decentralised systems? Water, 39 1:79-82.
Moglia, M., Sharma, A. and Tjandraatmadja, G. (2012) Industry and householder perceptions on rainwater tank maintenance, Water Science and Technology: Water Supply 13 (2), in publication
The outcomes of this research are relevant to the development and revision of the current and future SEQ Water Strategy and Queensland Development Code relating to Sustainable Buildings.
It is also highly relevant to decentralised systems in other areas. Designers, developers, consultants and wider water professionals can apply the Alliance's findings in the planning and implementation of water and wastewater services – both for greenfield and infill development. Maintenance and management models remain a large challenge. As a component of the knowledge adoption process, a national workshop was undertaken to summarise the research and its implications. Outcomes and recommendations from the workshop are summarised in papers presented at that workshop.
Project Workshop-Rainwater Tanks as a Component of Urban Water Systems,
28 August 2012
and Field Trip-Decentralised Wastewater and Rainwater Tank Systems,
29 August 2012
Dr Ashok Sharma, CSIRO
Ph: +61 3 9252 6151