A Case Study In Water Sensitive Urban Design

This paper reports on a water sensitive urban design initiative by an owner builder at a private residence in Ipswich, Australia. The project applies custom, emergent and established technologies to the management of the owners’ lifestyle preferences and problematic site conditions. It is also an innovative project from the perspective of current governance conditions, making use of previously untried regulatory mechanisms. The project comprises two integrated components: rainwater harvesting and onsite waste treatment, potentially offsetting household reliance on the mains water supply by as much as 90% and offering further beneficial externalities. Rainwater is harvested from a 135m roof catchment through a conveyance system that includes leaf diverters and screens, though no first flush diverter, to a 15kL PE storage tank. A high performance pump feeds the rainwater successively through a filter and water meter to a Bianco Rainsaver which enables switching between the rainwater supply and mains water back-up. Water is supplied throughout the house via a PE-X water service to every outlet except the kitchen sink. The kitchen sink (plumbed separately) permanently draws from the mains water supply, a necessity with Ipswich City Council regulations. Flow restrictors and AAA (or higher) rated fixtures and fittings are used throughout the home and a 30-tube 315L Endless Solar hot water service is used. All waste water (black and grey water) is processed onsite in an OzziKleen RP10A advanced secondary treatment plant that features custom modifications for this project (due to site conditions, but not affecting system performance). Permission to install the OzziKleen RP10A system was obtained under s4 of the Queensland Plumbing and Wastewater Code 2006, with this project as a test case. The paper presents the author/owner’s experience researching, installing and using the various technological components. It addresses problems and resolution of relevant compliance and regulation issues, with conclusions drawn from these experiences. It concludes with plans to operate the site as a non-commercial community education project. 

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