New report tackles groundwater issues for new WA community

What happens when a new development site in an aspiring water sensitive city faces significant water management and urban design challenges?

The development manager (PEET) and the land owner (the WA Department of Communities) calls in the CRCWSC to work with local water and development industry experts to formulate innovative on-ground solutions that challenge conventional practice.

That’s exactly what happened for the new community of Brabham—a sustainable and affordable housing development in the north east urban growth corridor of Perth—and the result is six innovative water management solutions, designed collaboratively by the CRCWSC and stakeholders.

Brabham faces three main water challenges:

1. High groundwater tables on some sections of the development site, causing water-logging in the winter months and requiring 2,500,000 m³ of fill across the site (the single largest development cost)
2. A significant shortfall in irrigation water for the community’s proposed public open space
3. A significant projected shortfall in non-potable water for the entire South Swan region by 2040.

To tackle these challenges and identify practical, evidence-based solutions, the CRCWSC co-hosted a collaborative workshop with PEET and the WA Department of Communities.

The workshop created a forum for collaboration and research translation and resulted in a set of innovative ideas to make Brabham water sensitive and a sustainable, liveable community for its estimated 12,300 future residents.

The six ideas, outlined in the newly released Ideas for Brabham research synthesis report, are:

1. Staging—staging development parcels to create time and space for innovation. The development deals first with the areas least affected by groundwater issues, taking time to test the designs that will be used in areas where shallow groundwater is a constraint. The first stages will become a showcase for later stages.
2. ‘Village in a wetland’ development typologies—adapting the urban development product to the wetland landscape to celebrate water in the landscape rather than fight against it.
3. Minimal fill objective—reducing the amount of fill required by adopting an alternative to gravity sewers and varying the design parameters for sub-surface drainage.
4. Harvest the additional recharge for reuse—harvesting the water that results from the difference in groundwater heights between post-development water tables and pre-development levels, to return a more natural hydrology and provide a local water source.
5. Expand the non-potable water network—creating a water grid for Brabham and beyond by using supplies from a range of different sources, such as treated wastewater, surface drainage water, rainwater, and storage solutions such as managed aquifer recharge.
6. Governance for innovation—responding to the twin challenges of how to support innovative proposals for Brabham through various approval processes, and how to drive broader reforms that will enable the wider adoption of these innovations in future development.

Once complete, Brabham will be a sustainable and affordable housing community, with 3,000+ dwellings, as well as schools, neighbourhood shops and recreational areas for young families and older people. It will also be a major transit-oriented hub linking the Swan Valley to Perth’s CBD, 23 km away.

The CRCWSC is excited to be involved in this project—part of Perth’s goal to be ‘Australia’s most water sensitive city’. With proper water management and water use efficiency, clever use of green infrastructure and built environment construction methods, and water sensitive governance, Brabham can provide a practical demonstration of several elements of a water sensitive city.

Emma Yuen (WA Regional Manager) said: “There is a shared agenda for innovation, and project level partnerships are already in place to facilitate this outcome.”

You can learn more about the ideas for Brabham in the report.