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After the Deluge

Flood-ravaged parts of Australia are slowly recovering. But questions about climate, building practice and planning must be addressed, reports Jo Stimpson.

In Australia, where muddy waters have plagued Queensland, Victoria and New South Wales for weeks, an enormous clean-up operation has begun.

The floods - which began in December in Queensland, north east Australia - are already said to be one of the most costly natural disasters in Australia’s history, with rivers peaking at over 14m in a number of areas. Flood waters peaked at 9.2m in Rockhampton, and at 4.46m in Brisbane. More than 3.1M people have been affected overall.

The majority of Queensland was flooded, with three quarters of the state declared a disaster zone. Floods were also declared disasters in parts of Victoria and New South Wales, and have also affected Tasmania, to a lesser extent.

80 towns flooded in Victoria

In Victoria, state emergency service spokesman Lachlan Quick says around 80 towns in the state will have been flooded by the end of the disaster. At this time of year, Victoria is usually tinder dry and at the peak of its wildfire season.

Seventy seven local government areas were declared disaster zones in New South Wales. “These councils cover large areas, and have many hundreds of kilometres of gravel roads and dozens of bridges impacted by the heavy rain and flooding,” said state emergency services minister Steve Whan. “Few regions have been spared from this extraordinarily intense and damaging weather system.”

As NCE went to press, it was estimated that more than 30,000 homes were damaged or destroyed in Queensland alone, but deputy prime minister Wayne Swan has said it is “still too early to quantify the impact with any certainty at this stage”.

The usual challenges of disaster management have applied to the flood relief effort - making sure everyone has a roof over their head; raising much needed funds; and putting mechanisms in place to ensure money is distributed effectively.

Long term issues

But beyond those immediate tasks, longer term issues will affect how the country responds to, learns from and moves beyond the events of the past month.

Victoria still lies beneath high flood waters, but tentative sprouts of recovery are already visible in the re-opening of some train lines and of 70% of the flooded roads further north in Queensland. Freight movements have also resumed after sunken yachts, uprooted trees and large domestic freezers were cleared from the Port of Brisbane.

“Few regions have been spared from this extraordinarily intense and damaging weather system”

Steve Whan, State Emergency Services minister

 

Queensland has established a Reconstruction Authority to oversee rebuilding work. This will be given legal powers to override bureaucracy in order to implement the Queensland Reconstruction Authority Board’s disaster recovery recommendations. Around 100 engineers from the Queensland Department of Public Works and 55 staff from private contractors are engaged in the Queensland recovery effort.

But questions are starting to swirl around the floods. One of the most remarkable things about the event is its stark contrast to the severe drought that has plagued this region for the best part of a decade. Millions of Australian dollars have been spent in recent years on desalination plants, treatment plants and major pipelines to maintain water supply to the area - all of which look to have been to an extent rendered unnecessary by the new water surplus.

Flood inquiry

An A$15M (£9.3M) inquiry into the floods - launched by the Queensland government last week - will undoubtedly look at whether investment should have focused more on flood defences. The media certainly seems to think so. In particular, The Australian newspaper reports that the government failed to act on a secret report carried out in 1999 by scientific and engineering experts and seen by the newspaper. This says that said tens of thousands of Brisbane homes were inadequately protected.

But diverting investment away from flooding may not be the only legacy of the drought. It could also contributed to the collapse of an earth irrigation dam in the Darling Downs, West of Brisbane, which held 1.8bn litres of water but burst its banks in late December. Regional consultant Aquatech Consulting managing director Jim Purcell, an irrigation dams specialist, says the change from extremely dry conditions to extremely wet ones could have been behind the structural failure.

Purcell says the drought period is likely to have caused the dam’s earth soil to dry out to the point of extremeshrinking and cracking, potentially leading to structural weakness.

“Maybe it’s not about rezoning, maybe we’re saying if you live in that area you have to have a house on stilts for example”

Anna Bligh, Queensland premier

 

Further complications would have arisen if the soil is dispersive, meaning that when moist its clay particles are prone to separating from one other. This could have made it easier for water to flow through the embankment, causing it to fail.

And engineers should be aware that more structures could encounter problems could appear when the ground dries out says University of Queensland emeritus professor Colin Apelt. He says embankments could fail due to slump - a slipping of material down the curved surface of a slope, which can occur if the flood level recedes so quickly that the water cannot drain from within the embankment.

Rip off merchants

Fears about substandard reconstruction work have also emerged. Hundreds of Australian tradespeople have already signed up for repair work, but the Victorian state government has warned that con men in the industry are looking to capitalise on the vast amount of work that will be available.

“They target the vulnerable, offering to redecorate or mend fences, driveways and roofs. They often demand money up front, start the job and leave it unfinished,” said consumer affairs minister Michael O’Brien. “It’s disturbing to hear there are people taking advantage of Victorians in their hour of need.”

In Queensland, minister for public works Robert Schwarten has warned that homeowners might be rushing into repair work that will need correcting later due to moisture problems. Resheeting and repairs should not be carried out until the moisture content in a house’s timber wall framing drops below 16% and the framing is in a sound condition, he said.

The government is also keen to avoid haste when it comes to the wider reconstruction of destroyed homes and major infrastructure. The disaster is raising serious questions about the prudence of building on flood plains, which will be a key focus of the floods inquiry, says Queensland premier Anna Bligh.

Hard questions

“We’ve got some real questions before we just rush in and rebuild exactly what was there in exactly the same place,” she said.

“They’re hard questions but I think this event demands that we ask ourselves hard questions.” She said homes could be moved from flood plains to safer areas, or they could be rebuilt in a more flood-proof style. “Maybe it’s not about rezoning, maybe we’re saying if you live in that area you have to have a house on stilts for example.”

The idea is not as radical a change as it sounds. In Queensland, homes on stilts are in fact traditional. A distinctive example of Australian architecture, the “Queenslander” is a type of house characterised by timber construction set on tall timber stumps, with open verandas at the front or back. The large gap beneath the house improves ventilation, prevents the termite infestations to which timber is vulnerable, protect against flooding in the rainy season, and allow homes to be built with minimal earthworks.

Queenslander houses fell out of fashion after the Second World War, when earthworks became cheaper and speedy, simple construction became a priority. But after this month’s floods, the government consider recommending this form of traditional design.

Between the drought, the threat of inadequate reconstruction, and the debate over building on flood plains, there is a great deal for Australia to chew over once it recovers from this crisis. How soon that point can be reached is still uncertain, as fresh havoc threatens to unleash itself.

Vulnerable levee

In Kerang, Victoria, a levee holding back the swollen Lodden River is the only thing protecting 1,500 homes - and the authorities fear it could give way. “The primary concern is the ability of the levee to withstand high flood levels for an extended period of time,” said State Emergency Service spokesman Kim Healey.

Perhaps more worrying is the fact that Queensland’s usual storm season is just beginning. Summer storms have already caused renewed damage in some flood-hit communities. Even a small cyclone, such as cyclone Tasha that hit the coast in December and brought “monsoonal” rain with it, could be devastating.

“We haven’t seen a cyclone - touch wood we won’t see one - but we’re prepared for it if it comes,” says Bligh. “As much as we’re focusing on recovery, you can rest assured our emergency response people are regrouping and ready.”

It means that while Australia pushes forward with the immediate recovery effort and thoughts of the long term future, it is forced to prepare for the prospect of being put back to square one.

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