Water sensitive city: Melbourne’s journey into integrated water management

Over the past seven years, Melbourne has been on a journey to reimagine the city’s water, including rethinking governance, reimagining urban water management and redefining value. 

Presenting at Ozwater’24 on Melbourne’s progress in integrated water management (IWM), Arup Australasia Integrated Water Management Lead Celeste Morgan said IWM is often considered in relation to ‘three waters’. 

“This is water supply, stormwater and wastewater. This is the beginning of thinking about the concept, but IWM isn't about optimising those three sources separately. That's not it,” she said. 

“What we need to be aiming for is strong IWM where we realise the overlaps, but where we also integrate it with city strategies, planning and placemaking, and consider how we can be more productive, create better urban design, and really celebrate water in the places that we're creating, not just as a servicing strategy.”

Morgan said that the core of this integration is about recognising and understanding ‘urban metabolism’.

“In water supply terms, we often worry about population growth. We worry that we are growing too fast and that we don't have enough water. But the more we grow, the more wastewater and stormwater we have and the more recycled water we can produce,” she said. 

“So how can we reconnect that cycle and embrace growth as an opportunity to reinforce our water supply equation as we go?

“If we add stormwater and wastewater together, it is more than the amount we need in terms of water demand. When we consider stormwater and wastewater as a resource, we're always in a situation where we have more water than we need.

“So how can we actually harness that excess, but also think about where that excess is going if we're not harnessing it, and make sure it's managed well?”

Building benefits

Discussing Water for Life – greater Melbourne's water systems strategy for water supply – Morgan said the plan demonstrates that IWM delivers the best benefit cost-ratio in terms of livability and water security.

“[IWM] provided a lever to bring Councils into the equation to consider stormwater and rainwater harvesting as part of water resilience, rather than focusing on more traditional sources,” she said. 
“Another major development in Melbourne has been to set waterway targets in terms of recognising the impact of stormwater, and that we need to be harvesting for waterway health, as well. 

“Having those targets both from a water supply and a waterway health perspective has been really helpful in driving us forward and thinking about local solutions for IWM to capture local water and reuse it.”

When it comes to integrating all of these IWM approaches and solutions into placemaking, Morgan said a key driver is the circular economy, with more opportunities surfacing as cities change and grow. 

“The circular economy aspect of where Melbourne is going is pretty exciting. We already produce 41% of our own food within Melbourne's food bowl, which is an astounding statistic. But productive landscapes are at risk from a lack of water supply, but also in the expanding city,” she said. 

“So how can we make those two complimentary? 
We've also got exciting opportunities on the horizon with things like hydrogen coming into play, which could be a consistent local supply demand for alternative water, and could unlock some opportunities to take integrated water management further.”

Defining value

Redefining value is a key aspect of working towards IWM, Morgan said, with water managers and utilities expanding their traditional roles and the benefits they can provide to urban places via water services. 

“Redefining our targets is really about challenging the organisational structure and funding structures behind it. Water utilities are changing their roles. They're now seen as enablers of liveability, not just water service providers,” she said.

“Questioning how they operate in their catchment, what they do with stormwater, what they do in terms of placemaking, what they do with their own land – all of these questions are coming to the fore and expanding their sphere of control beyond just a service provider. 

“Irrigation and having water in the environment plays such a huge impact on that, and measuring the health and the livability of having greening urban spaces is all very important. Looking at monetising the benefits and where costs can help us reshape funding structures.”