Increasing water efficiency and discovering new water sources in the face of rapid population growth is a major challenge facing modern cities.
CRC for Water Sensitive Cities and University of Queensland researcher Dr Steven Kenway discussed the role of urban metabolism in finding solutions to modern water challenges on ABC Radio National program Ockham’s Razor, in a talk being broadcast this Sunday.
Dr Kenway said assessing urban metabolism involved quantifying “all flows of water, energy, food and matter” in a chosen city with the goal of balancing the city’s inputs, outputs and storage.
He argued that the current conceptual model of water balance is that water ‘supply’ must equal ‘demand’, which doesn’t take into account sources such as rainfall and stormwater or how the city is influencing water flows.
“If we think metabolically, we ask how does a change in efficiency, or a new supply, influence water flowing into the city as well as water flowing out. For example, dual flush toilets influence both the inflows and outflows of water in cities,” he said.
While some Australian state governments invested in expensive water infrastructure such as desalination plants after the recent drought, Dr Kenway said cities often had “large flows of untapped water sources that might be used.”
His research on Sydney, Melbourne and Brisbane revealed “more than double the water demand of the cities fell as rainfall on the city each year. If we had designed our cities to be able to capture, store and use this rainfall there would be far less pressure on the centralised water system”.
Dr Kenway is part of the Catchment-scale landscape planning for water sensitive city-regions in an age of climate change (Project B1.2) and Managing interactions between decentralised and centralised water systems (Project C3.1) research teams. A report on his previous research on urban metabolism is available free here.
Dr Kenway’s talk will be broadcast on Radio National this Sunday at 7.45am and available as a podcast on the Radio National website: