Modelling water sensitive cities to create resilient communities
Rather than taking a business-as-usual approach, the rapid growth of Australian cities provides an opportunity to change the way we view urban planning and the water cycle, Professor Jurg Keller told attendees at Ozwater’19 last week.
Keller is the founder and Deputy Director of Research at the University of Queensland’s Advanced Water Management Centre, and was Chief Research Officer at the Cooperative Research Centre for Water Sensitive Cities (CRCWSC) until March this year.
In a presentation on city-scale planning, he said urban development and water cycle planning should be integrated into a single process in order to create sustainable, water sensitive cities.
“Australia is one of the places where growth is so rapid that we struggle, but at the same time we have an opportunity to change the way we grow and not just turn over existing assets,” Keller said.
“There is a range of complexities and it’s far broader than water.”
Even within water, development considerations extend beyond water supply and sanitation to stormwater and flooding, urban cooling and creating green spaces.
“Plus, in most cases, we’re not dealing with a clean slate,” Keller said.
“We can’t usually start from scratch and design a new city. Most of the time we have to use existing systems, resources and infrastructure, and try and improve on those.”
It can be difficult to predict how existing systems and infrastructure will react to future development, which is why the CRCWSC has developed the Water Sensitive Cities Scenario Tool.
This is a Geographic Information System-based digital representation of a city that helps users see how infrastructure, water networks and population demographics will change over time.
It simulates different development scenarios and assesses these for changes in water sensitive city outcomes, including effects on the microclimate and urban water cycle.
Users can input their own data into the tool (for example land use, zoning and water network information) along with available information like climate and rainfall projections, heat modelling and census data.
“Creating a water sensitive city has to be driven by a vision that informs the planning and creates the solutions,” Keller said.
“We need to diagnose where the issues are, identify targets and objectives, analyse the options, factor in externalities like climate change and develop solutions.”
Along with modelling different scenarios, he said the tool is important as it can help make the case for investment in water sensitive urban design (WSUD).
“We can show what will happen if we keep going the way we are, but the tool also shows what else we can do,” Keller said.
“It shows the impact of green technologies, rainwater tanks, planting trees, irrigated areas … as well as what is happening with water and runoff and nutrient management.”
Crucially, the tool also represents the impact of development on air and land surface temperatures, which Keller said is a great way of showing stakeholders the importance of WSUD.
“Heat is one of the hooks when talking to decision makers because they can see and feel it,” he said.
“This is important because we have a real challenge and an opportunity moving forward … If we continue to build what we’re building, we’ll go backwards.”