Optimisation of mains trickle topup supply to rainwater tanks in an urban setting

Abstract

The use of rainwater tanks as a supplement to traditional domestic urban water supply systems is becoming increasingly common, especially given growing environmental awareness and ongoing drought conditions. Such tanks must be appropriately configured in order to effectively meet demand. Two important aspects of this configuration are the preset mains trickle topup rate and trickle topup volume. Improper configuration of these parameters can result in ongoing tank failure. As such, there is a need to improve our understanding of how these parameters influence tank performance in various rainfall climates around Australia. This paper reports part of a study undertaken to address this need. For a range of topup volumes (but only one set trickle topup rate) it is shown that tank performance is highly dependent on climatic regime and demand, and only very weakly dependent on tank size. Seasonal variations in tank failure are investigated and correlated with rainfall and yield patterns. This represents the first stage in a wider study that will subsequently incorporate investigation of the role of other variables including trickle topup rate and climate change.

Keywords:

• Modelling
• rainwater tanks
• trickle topup volume
• yield
• failure

Additional information

Notes on contributors

M E Barry

Michael Barry is an Associate of WBM Pty Ltd with honours and PhD degrees in environmental engineering. Michael has experience across a range of environmental engineering disciplines, including 1, 2 and 3-dimensional hydrodynamic and water quality modelling, and integrated water cycle management. Michael’s focus has been the use of modelling tools in these areas, and he can relate modelling outcomes and processes to the management of urban water cycles.

P J Coombes

Associate Professor Peter Coombes is a conjoint senior research fellow of Integrated Water Cycle Management in the School of Environment and Life Sciences at the University of Newcastle. He is also the managing director of the consulting company Urban Water Cycle Solutions and a research project leader in “innovative WSUD intervention techniques to counter evolving urban form and deteriorating environments and infrastructure” in the eWater Cooperative Research Centre. Peter Coombes has a PhD in water systems engineering and microbiology, degrees in Civil Engineering and Surveying, and an Associate Diploma in Engineering. His research interests include integrated water cycle management, water sensitive urban design, water quality and systems analysis. He has written a number of guidelines including co-authorship of Australian Runoff Quality and is a member of the urban water advisory panel to the National Water Commission. He is currently the chair of the organising committee and scientific panel for the 2007 International Rainwater Catchment Systems and WSUD conference.