Tapping the Urban Catchment | Demonstration Site - Warrnambool | National and State Wide Initiative | The Benefits | Factsheets | Contacts 

Many townships and cities around the state and nationally are experiencing dwindling water resources and are looking at extremely expensive augmentation options.  Regional rain water harvesting from roofs in the growth areas of these towns utilising the new catchment created by the housing is far more cost effective than individual tanks and is a viable alternative to other augmentation options.

Tapping the Urban Catchment

The regional harvesting of roof water is a viable means of supplementing the existing water supply from an economic, environmental and social perspective.  The first phase of this project sees rain water harvested from 142 rooftops in a new residential subdivision in Warrnambool and transported through pipes to an existing raw water storage managed by Wannon Water. From there it is treated and becomes part of the drinking supply for Warrnambool. This harvested roof water will represent 76 per cent of the subdivision’s annual household demand.

The 142 lot Warrnambool subdivision demonstration site provides a valuable working example of how developers, water corporations and Councils can work together to reduce the water resource impact of expanding residential areas by simply harvesting the water from the roofs that are causing the increase in demand.

The principle is very simple and adaptable to any scale of township that is growing.  Whether the growth is in terms of hundreds of houses or tens of thousands of houses, the opportunity exists to install the necessary infrastructure as the subdivision proceeds to ‘tap’ the new catchment.

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Demonstration Site - Warrnambool

The roof water harvesting project is a demonstration project within the Russells Creek growth corridor of Warrnambool involving a 142 lot subdivision.  It is a partnership between the developer (Cove Land Developments Pty Ltd), the Federal and State Governments, Wannon Water and the Warrnambool City Council. The project will utilise roof area in a new subdivision of Warrnambool as an urban catchment to harvest water for future use in Warrnambool’s water supply system. Download a map of the demonstration site area. In detail, the project involves construction of a dedicated roof water collection pipe network, involving approximately 2,000 metres of trunk mains and 2,200 metres of smaller diameter collection pipes within the subdivision. This pipe network will capture rain water collected on household roofs and transfer it to the existing Brierly basin storage via a dedicated transfer pipeline. The roof water will be mixed with other raw water, already in the basin, be treated at the Warrnambool Water Treatment Plant and then supplied to the city’s reticulation system. Preliminary figures suggest that this project will meet approximately 75% of the annual demand of these properties. The works were completed by the end of June 2010 allowing new houses built within the subdivision to be connected. This project offers numerous direct and indirect economic, environmental and social benefits, making it a “showcase” of sustainability for the rest of the nation through the better use of available water resources and water sensitive urban development.  Innovation The project is believed to be the first of its kind in Australia It will provide a working demonstration of a more sustainable approach to water management by using the new “catchment” of roof area created in population growth areas. A tool kit will be developed by Wannon Water to assist other cities to identify how they can use the same approach.

National and State wide Initiative

Roof Water Harvesting Project - Funding has been provided through the Australian Federal Government “Water for the Future" program and from the Victorian State Government "Stormwater and Urban Recycling Fund" allowing the demonstration site to be established and the regional harvesting principle to be explored in other areas of Australia.

The project is consistent with the following key elements of the National Water Initiative: water planning framework, integrated management of water for environmental and other public benefit outcomes, water resource accounting, urban water reform & seeks knowledge and capacity building.

Further, the project delivers across a wide range of specific actions listed within the Victorian Government White Paper “Securing Our Water Future Together”, as outlined below.

• Action 5.13. The Government will set an aspiration target for new development to achieve at least 25% savings in water use.
• The project will see each new dwelling generate 145kl per annum (74% of current average consumption).
• Action 5.16.  The Government will require urban water authorities to plan for new growth areas in the development of their Water Supply Demand Strategies.
• The area under consideration is the single largest green field residential growth area in the region. Wannon Water, via this project, is providing water for this growth area.
• Further, the project will contribute to a more successful Water Demand Supply Strategy by providing a beneficial lift in the supply curve. 
• Action 5.25.  …all urban water authorities to assess opportunities for the use of …other alternative supplies….inclusive of rainwater.

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The Benefits 

Aims and Objectives
The project aims to develop and communicate an innovative working model of the utilisation of the roof area in new subdivisions as a dispersed catchment supplying centralised storage, treatment and reticulated water supply systems.  The project is a water supply augmentation project which combines the strengths of the Authority’s water management capabilities with a “new take’ on rainwater collection through a devolved collection system which will maintain high standards with cost effective delivery.

Primary objectives are:

• Construction of the necessary infrastructure to capture and transfer rain water collected on new household roofs to existing centralised storage and treatment facilities avoiding the need to transport this water from a river system over 100 km away.
• Identifying other cities with high potential for adoption (primarily in coastal eastern Australia) and the provision of a tool-kit for locality-specific identification of application.
• Identification of any other regulatory or other barriers to the widespread adoption and uptake of this “alternative source of supply”.
• Reporting of yield, quality and cost information to support adoption under HACCP-based risk systems for water supply.

Economic:

• Is a more consolidated and effective manner to harvest and use rainwater than the adhoc and scattered approach of individual landowners installing individual tanks, pumps and pipework on their land.
• Is able to be implemented progressively as development (and consequential demand) proceeds in the growth corridor.
• Reduces operational costs of transporting water long distances.
• Defers the need to augment the existing raw water delivery system and need to develop and harvest water from new groundwater resources. If this principle were adopted in other growth corridors with new development being close to “water demand neutral”, the time period of deferring augmentation would be very long.
• Reduces the works required for stormwater management for Council and developers e.g. size of stormwater detention basins and treatment systems.

Environmental:

• Reduces the energy use and associated greenhouse emissions for transporting water for use in Warrnambool.
• Diverts water to a beneficial use instead of running to waste and causing a down stream flooding and negative impact on local estuarine stream systems.
• Improves the environmental flows in the Gellibrand River.

Social:

• Reduces public health risks implicit in alternative recycled water or decentralised individual rainwater tank systems.
• Landowners will not be burdened with ongoing maintenance of an on-site harvesting and reuse system.
• Is innovative in approach to sustainable use of water resources, and promotes community consciousness of innovative outcomes that can be achieved in the water cycle.

Indirect benefits include:
The design and construction of a working example of how such a rain water harvesting system would work will provide the following indirect benefits:

• Demonstrate to developers that such a system is workable and does not impose unreasonable requirements on their development.
• Demonstrate to other developers of new urban estates, Water Authorities, Councils, CMA’s and the community that roof water harvesting is a sustainable, cost effective, environmentally friendly solution to reduce the reliance on other sources of water

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Factsheets

The following factsheets have been created to support the Roof Water Harvesting Project.

• Roof Water Harvesting - The Concept
• Roof Water Harvesting - The Benefits
• Roof Water Harvesting - A Case Study
• Roof Water Harvesting - Toolkit

Play the concept animation

Contacts

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