Antinuclear

The cause wasn’t an intense east coast low, a cyclone or intense rain event normally associated with flooding of low-lying areas across the region.  If it had occurred during daylight, particularly at peak hour, Mooloolaba would have been left grid-locked and Bradman Avenue, Maroochydore, reduced to one-lane along the river.

Twin Waters residents would have seen water up into the parks and footpaths along Twin Waters Drive and the river spilling into bushland for more than 100 metres along Nojoor Road.

At Caloundra the vulnerability of Tay and Maloja Avenues at Bulcock Beach would have been fully exposed.

What occurred required no more than a couple of days of strong southerly winds blowing up the NSW and Victorian coasts to set off the Ekman Transport Effect which lifted the Highest Astronomical Tide for the season at Mooloolaba from 2.03metres by additional 0.4 of a metre.

While for many the resulting impact of that degree of sea level rise went largely unnoticed, scientists at the University of the Sunshine Coast and hydrologists took note.

They are in agreement that Monday night’s short-term increase in sea levels afforded a glimpse of the future impact of the best-case 0.8 metre permanent rise now locked in by 2100 because of climate change.

The Ekman Transport Effect refers to the shift leftward that occurs when sustained winds blow in a consistent direction over the ocean moving the top 30m layer of water. The resultant upwelling is most likely to occur along New South Wales, south-east Queensland and the Bonney Coast (South Australia) coastlines.

Professor Tim Smith, director of the University of the Sunshine Coast Sustainability Research Centre, says the region has received a wake-up call in terms of what it needs to prepare for. “We are pretty lucky it was not combined with other things to intensify the situation like a low-pressure system or a high-intensity rainfall event or it would have been a much more devastating outcome,” Prof Smith said.

“We have to think about the design and placement of infrastructure and assets. We can’t continually defend and protect ad finitum. “Alternative adaptation strategies will be needed.”

He says the options are limited. The first is to try to protect assets without changing their location. Professor Smith said the approach was the emphasis of local authorities across Australia who don’t want to change but preferred to protect investments made in calm weather 40 years ago.He said the problem was that the environment was not static and could not be controlled.

The second strategy was to accept there were going to be impacts and to retrofit existing settlement and infrastructure to experience less damage. “You could raise houses to protect from periodic impacts if you were willing to live with them,” Prof Smith said.

The other option was to retreat in the process relocating settlement and assets out of harm’s way. “That’s a taboo subject, he said. “People don’t want to talk about it but eventually we will need to have a serious discussion.”

Hilo in Hawaii, Grantham in Queensland’s Lockyer Valley and Twin Rivers in New Zealand all provide limited examples of communities that have bitten the bullet and shifted their communities out of harm’s way.

“We can’t keep building walls higher and higher,” Prof Smith said. “The longer we leave it the more difficult it will become. The sooner we act the better.” He says the danger of protecting assets is that the protection gives confidence to put more in harm’s way, doubling the risk.

He takes issue with the failure of governments to be explicit about the planning time horizons of capital spending. If it’s 20 years it doesn’t matter. Longer than that may become problematic. What won’t cut it is a piecemeal response to climate change…… https://www.sunshinecoastdaily.com.au/news/how-flooding-provided-a-window-to-the-future/3216185/