Sustaining gardens with alternative water sources

New WA guidelines help navigate the way

Article by Melissa McGrath, Urban and Social Sustainability Consultant, Josh Byrne & Associates

Photo: Community bores support urban greening (image courtesy JBA)

Utilising alternative water supplies for landscape irrigation can supplement Perth’s Integrated Water Supply Scheme (IWSS) and help secure Perth’s water future. Adopting this fit-forpurpose approach can help accommodate Perth’s growing population and our preference for greener, cooler neighbourhoods, despite our drying climate. Yet identifying the most appropriate source and approach can still prove a challenge, with many unsure how to weigh up the pros and cons, then navigate and address the numerous site-specific planning, operational and governance requirements.

Recognising the need for greater direction in the uptake and implementation of fit-for-purpose alternative water supply systems, Josh Byrne & Associates (JBA), with support from the Water Corporation and various other stakeholders, has developed guides that focus on two areas of fit-for-purpose domestic water supply – community garden bores and recycled greywater. The Community Bore Guide provides information on implementing well managed community bore schemes, in areas suitable for a bore, for new residential developments in Western Australia. The West Australian Greywater Guide, developed in conjunction with the Greywater and Wastewater Industry Group (GWIG), provides a source of practical information on how to best reuse domestic greywater.

Responding to Climate Change The south-west of Australia is experiencing a drying trend due to climate change, with reduced rainfall since the mid-1970s significantly impacting on the runoff into Perth’s dams. Water solutions for Perth have included an increased use of groundwater and reliance on sea water desalination. Locally relevant and fit-for-purpose integrated urban water systems can support Perth’s existing water supply scheme and provide long term water supply solutions at a variety of scales including rainwater harvesting, stormwater reuse, as well as greywater and wastewater reuse. Uptake of these alternative sources can help to alleviate pressure on the IWSS, ensure groundwater dependent wetlands and ecosystems are protected, and connect people to the local water cycle.

Delivering the Waterwise Perth Action Plan At the same time as responding to a drying climate, Perth is also facing the challenge of meeting the needs of a growing population wanting to reside in a green, liveable city. To address these challenges, the McGowan Government and Water Minister Dave Kelly has led the development of the Waterwise Perth Action Plan aiming to transform Perth into a leading waterwise city by 2030. The Action Plan, released in October 2019, has been developed with knowledge and insights provided by over 200 stakeholders and seeks to take the next steps from saving water to improving how we manage water in our urban environments. Actions are divided across different scales for delivery and a collaborative approach has been highlighted as essential to achieving the Action Plan, with everyone in the community expected to have a role, including State Government, councils, industry, individual businesses and households.

As a key stakeholder in the delivery of the Waterwise Perth Action Plan, the Water Corporation will continue their commitment to exploring alternative water solutions for Perth. Most of Perth’s scheme water (70%) is used in our homes and more than 40% of this is used to water gardens. One of the ways to reduce this reliance on scheme water is the option to use alternative localised non-potable water sources for irrigation, such as greywater, and groundwater if done responsibly in suitable areas, combined with water efficiency measures to ensure that these sources are also used carefully.

The development of both the Community Bore Guide and The West Australian Greywater Guide support the journey towards a Waterwise Perth by providing direction to a variety of stakeholders and end-users for the uptake of alternative water supply systems as part of an integrated and balanced approach to water management. This is important for ensuring ongoing water security to support a growing population as well as protecting and enhancing healthy waterways and wetlands, and cool, liveable urban spaces.

The Community Bore Guide While groundwater supplies are under pressure from climate change and use, the efficient irrigation of domestic gardens with bore water can be a better alternative than using scheme water. Some developers have been exploring community garden bores as a cost effective and efficient way to supply bore water for this purpose. A community bore supplies groundwater via a reticulated network to properties in cluster to precinct-scale urban development for non-drinking uses, including private garden watering and for irrigation of communal green spaces. Components of the Community Bore Guide

The Community Bore Guide consists of two parts: • Community Bore Checklist. A summary document with a four-stage process to assist in site specific implementation including: planning, design, installation and operation. • Community Bore Report. A detailed document further explaining the four stages, including a process flowchart, example handover procedure and insights from stakeholder experiences.

Recommendations are included to ensure the community bore scheme remains a viable option, such as ongoing assessment of groundwater use, planning for the switch to a climate independent water source, minimising risk with effective governance, engaging the community and practicing water efficient behaviour.

Implementing a community bore can be a complex process that requires the involvement of numerous stakeholders and consideration of various planning, technical and operational requirements. To address this issue the Community Bore Guide has been developed as an information resource for developers, local governments or service providers interested in implementing a community bore scheme in suitable areas.

Benefits of implementing a community bore as part of integrated urban water management include: − The potential to provide a well-managed, fit-for-purpose alternative water supply at a scale that is cost-effective to operate. − Maintain or increase urban greening and improve local amenity. − Maximised water efficiency if implemented with individual metering, efficient irrigation systems and water efficient landscape design.

Using the experience gained and lessons learnt from various community bore schemes in Perth, the Community Bore Guide compiles information into the one source to ensure community bores are designed, implemented and managed to suit site specific conditions, community needs, and prevent overuse of Perth’s precious groundwater. Specific guidance draws from JBA’s role in implementing the successful community bore scheme at the WGV development by DevelopmentWA in White Gum Valley. Additional stakeholders provided support, review of material and experiential knowledge to assist in the development and completion of the Community Bore Guide.

The West Australian Greywater Guide Greywater is domestic wastewater from bathrooms and laundries that can be diverted to the garden via simple low-cost technology to provide an alternative water source, alleviating pressure on scheme water supply. A reliable supply of greywater for irrigation can help to create green and cool neighbourhoods and contribute to meeting Perth’s wastewater recycling targets whilst reducing wastewater volumes requiring treatment. Benefits of greywater reuse include: • Reduced scheme water demand and wastewater discharge. • Lower household bills. • Restriction free water supply for gardens, especially in drier months.

The West Australian Greywater Guide has been developed as the go-to source of useful and practical information on how to best use greywater in Western Australia, with a focus on the Swan Coastal Plain of Perth. The Greywater Guide targets developers, planners, designers, builders and plumbers, homeowners, state and local government agencies; with specific benefits for each group outlined. A series of four Fact Sheets are included for easy dissemination of information as well as an example of how to include greywater requirements in design guidelines for architects, builders and consultants.

Department of Water and Environmental Regulation

DevelopmentWA (formerly LandCorp)

Department of Health

Department of Planning, Lands and Heritage

Water Corporation

City of Fremantle

TABEC

Total Eden

Urban Development Institute of Australia

Urbaqua

WA Local Government Association

Western Irrigation

The West Australian Greywater Guide

Department of Communities

Department of Water and Environmental Regulation

Development WA (formerly LandCorp)

Department of Health

Water Corporation

Greywater and Wastewater Industry Group

Components of the West Australian Greywater Guide

The West Australian Greywater Guide includes information on: • Regulatory guidance for effective greywater system installation and use, including the ‘Code of Practice for the Reuse of Greywater in Western Australia’ (Department of Health, 2010), Australian Standards and Plumbing Codes. • Methods of greywater use, with a focus on greywater diversion devices. • Approvals and greywater system components: drainage collection pipework, greywater unit, and irrigation area. • Application area and calculation, local context, landscape and irrigation considerations. • Design and technical considerations, including feasibility considerations and case studies of new and existing homes. • Indicative costs to supply and install a greywater reuse system. • Installation advice, including using an experienced greywater professional (contact via GWIG website) to design and install the system. • Maintenance advice for the pump, filters, irrigation system, soil and plant health inspection, diversion to sewer and scheme water top up. • Water quality, product selection, chemicals in the water and plant health advice. • Suitability for regional areas and checklist.

Download the Guides The Community Bore Guide and The West Australian Greywater Guide are available for download from the JBA website. There are other complementary resources prepared by JBA too, including the Residential Greywater-Ready Plumbing Guidelines and the Water Efficient Landscape and Irrigation Guide. Go to www.joshbyrne.com.au/resources

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