Flooding questions


By Liam Murphy

Calls for Perth’s stormwater drainage system to be overhauled are being made.

Urgent action needs to be taken now to address the future of Perth’s stormwater drainage system as the frequency of heavy rain increases, according to Professor Peter Newman, head of Curtin University’s sustainability policy institute and coordinating lead author for transport on the UN Intergovernmental Panel on Climate Change.

With the most recent report from the IPCC reminding the world that rapid action needs to be taken now to combat the effects of climate change, Professor Newman said he believed urban flash flooding was a problem that’s being overlooked: “It’s a constant issue I worry about. Being on the IPCC, I see how the climate is changing globally, but locally, one of the things we don’t think about much about is stormwater.”

Professor Newman, who won WA’s scientist of the year award for 2018/19, said the State Government needed to take responsibility now and completely overhaul the drainage system.

He said: “This is definitely something that needs to be coordinated by state government, as part of their climate change adaptations strategy. … We need to think about this, on a wider basis, rather than just fixing up the odd drain here or there.”

Last July, Perth recorded rainfall on 28 days, which was a 75-year record. This frequent rainfall put pressure on the stormwater drainage system and caused significant flash flooding in the metropolitan area.

Professor Newman said these flash floods were only going to become more common as the climate warms.

“It’s only a matter of looking at [recent weather events], to see when you’ve got a 2-metre-deep creek running down Hay Street in Subiaco, this is the kind of thing that can happen anywhere now.”

Diane Evers, a former member of the WA Parliament, representing the southwest region for the GreensWA, advocated for better management of Perth’s stormwater drainage system while she was in parliament.

Before leaving Parliament, Ms Evers tabled a report on the management of urban stormwater in Perth. The report outlined the strengths and weaknesses of the system, with recommendations for future management.

She agreed with Professor Newman that the current management of the system is not adequate.

“A lot of our drains are blocked by things as simple as leaf litter, so very quickly a lot of our drainage system will block up and flood low lying areas.”

Ms Evers said that while she was in parliament, she had trouble identifying which department was responsible for controlling the quality of water going into our drainage system: “Because there is this variation as to who has control of each part of [Perth’s stormwater management], the actual quality of the water coming out isn’t controlled.”

She said the complicated management of the drainage system needed to be resolved, so issues such as urban flash flooding could be resolved quickly.

“If our government decided to put the money into looking into this issue, it would be a lot easier and cheaper to fix the system now rather than waiting till the damage occurs,” she said.

The Department of Water and Environmental Regulation, responsible for regulating the entire stormwater network, said it was carrying out its role in floodplain management and provided recommended guidelines for development in flood-prone regions to reduce the risk of urban flash flooding.