Cities embrace their water — and build resilience

“When we think about making decisions on how we shape our cities, that deep connection and stewardship of water is really important,” says Briony Rogers, a civil engineer at the Monash Sustainable Development Institute and director of MSDI Water, the institute’s water research hub in Melbourne, Australia.

Rogers’ work on ‘water-sensitive’ cities brings together her interest in applying civil engineering to shape the environment humans live in, and her love of the beaches and forests that surround her in Melbourne.

That interest began when she worked as a water engineer at a design infrastructure company and realized that, to create truly sustainable infrastructure, principles of sustainability needed to be incorporated from the very start of the design process.

Nature Spotlight: Smart cities

“When I thought about civil engineering, it wasn’t because I was excited by the concrete and the pumps and the valves,” says Rogers, who is also chief research officer at the Melbourne-based Cooperative Research Centre (CRC) for Water Sensitive Cities. “The decisions we make about our engineered landscape actually influence how we experience that environment as people, and also how we sustain and support animals and plants and biodiversity.”

Australia is home to the world’s oldest continuing culture, and Rogers says that partnerships with Indigenous communities are fundamental to creating water-sensitive cities and landscapes. “The Indigenous ways of knowing and being and doing provide a really important pathway for us to think more systemically and long-term and holistically [about] our relationship with water and with land, and our role as custodians,” she says. An important part of water governance is respecting the sovereign rights and intimate connections between Indigenous Australians and water and land, she says.

One of the projects undertaken by the CRC for Water Sensitive Cities was the rehabilitation of a waterway in Bendigo, northwest of Melbourne, in partnership with the traditional owners, the Dja Dja Wurrung people. Their knowledge of Bendigo Creek and how to restore the ecosystem to health was combined with hydrological design and technology to create a naturalized waterway that improved water quality, habitat and biodiversity, and the traditional owners are now leading the project.

Australia is also a “sunburnt country” and known for its “droughts and flooding rains”, as Dorothea Mackellar put it in her poem My Country. That has been felt most acutely in the past five years, during which the nation experienced its worst drought, most devastating bush-fire season and record-breaking floods. Climate change is a major factor in all three of these, and is all but certain to result in a rise in both the frequency and severity of extreme weather events — particularly those involving either a shortage of water or too much of it at once.

That requires a radical rethink of how cities are engineered at the macro and micro scale, not only to insulate cities against water shocks, but also to use water to make them more liveable and healthy.

There is a tension between cities and water. Major towns and cities are commonly located next to water sources, such as rivers or bays. But many have been developed in ways that dislocate them from their water environments, Rogers says, such as by “draining swampland and building over the top of it, and then being surprised, when it has a big rainfall, that the water bubbles up and floods the local area”.

A water-sensitive city gives water an enabling, rather than a destructive, role in the landscape. For example, in an area at risk of flooding, the infrastructure needs to mitigate that risk. And with smart, water-sensitive civil engineering, it’s possible to do so in ways that safely make use of that water for beneficial purposes when it’s available.

Instead of being directed away from the city via pipes or drains, storm water can be captured, stored and used to irrigate gardens and public parks, which then provide shade and other cooling effects during periods of drought and extreme heat. Playgrounds can serve as temporary catchments for excess rainwater, with technology such as artificial sand aquifers and ‘wicking beds’ that can use it to water parkland grass. Nature-based solutions such as green roofs and green walls can not only mitigate extreme rainfall by capturing or slowing the flow of water, but also filter particulates and pollution from the water, increase biodiversity by providing habitat, food, and shelter for insects and birds, and cool the local environment through shading and evapotranspiration.

“You can’t manage storm water in a big centralized way because it falls everywhere,” Rogers says. “You need to be able to manage storm water across the whole landscape.”

The principles of water-sensitive design are being applied to a substantial development in Melbourne called Fishermans Bend, which is being touted as its second central business district. In a city that is known for experiencing ‘four seasons in one day’, including extreme heat, the design focuses on creating a district that is green and cool in summer, but also well prepared for extreme rainfall and flooding. Existing underground drains are being combined with green depressions or catchment areas that also serve as public parks. Infrastructure for recycling waste water and storm water, both large-scale and for individual buildings, helps to conserve water, while tanks reduce runoff.

In another part of Melbourne, a biodiverse area once known as the Great Swamp is being redeveloped, with the preservation of that biodiversity as one of the aims. Researchers are piloting an approach using ‘bio-sponges’: areas of vegetation that filter and partly capture stormwater runoff while also sheltering sensitive vegetation and protected species that live in the area, such as the growling grass frog (Litoria raniformis). China has taken the sponge idea one step further and is developing what it calls sponge cities, in which the urban landscape as a whole can absorb and make use of water.

For Rogers, a water-sensitive city is “green, cool, beautiful”: a place of experimentation and innovation, of connection and hope.

“Sustainability is a process rather than an outcome,” Rogers says. “The way that we organize ourselves, the way that we design our cities, the way that we manage our resources within cities — it’s got to be able to sustain us over the long term.”