Guest essay by Eric Worrall
In 2021 the ABC provided historical records showing a rapid series of floods is not unusual for Brisbane. In 2022, major flooding in quick succession is proof of the carbon demon walks among us.
Worse weather and more floods: The IPCC report contains warnings Australia should heed
By national science, technology and environment reporter Michael Slezak
This week we saw large parts of the country engulfed by flood waters.
People fleeing torrents raging through their living rooms, others wading neck-deep across rivers that were once roads. Some clung to their roofs, dotted like islands in a sea of murky brown, others rescued by neighbours in dinghies.
Some were trapped by landslides. Some even lost their lives.
This week, we also saw the world’s most comprehensive analysis of what climate change was doing to us. How it’s going to get worse, and what we can do to prepare.
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Climate change is already upending the lives of billions of people around the world and will definitely get worse over the coming years and decades.
Continuing warming — and worsening impacts — are inevitable, with some of those impacts beyond our ability to adapt.
For example, the increasing heat will kill hundreds more people in Melbourne, Sydney and Brisbane, no matter what. But it will kill hundreds more again, if we don’t act quickly to cut emissions.
The projections about future flooding are incredibly worrying. The report says with sea level rise of just 0.5m — which we will likely see this century, and maybe as soon as 2050 — what is currently considered a “one-in-100-year flood event” could happen “several times a year”.
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Just a year ago, in 2021, the ABC said something quite different about Brisbane’s tendency to flood.
What astounds about floods in Brisbane is that they continue to take us by surprise
ABC Weather / By Kate Doyle Posted Sat 16 Jan 2021 at 6:00am Saturday 16 Jan 2021 at 6:00am
A decade ago, as Brisbane’s record floods receded, many residents were left shocked and awed that such a devastating inundation could happen to a modern city.
But while there is no denying Queensland’s rainfall events of late 2010 and early 2011 were exceptional, Brisbane had flooded before — and it will flood again.
It is a history we can ill afford to forget as we continue to live and build on the flood plain.
The most astounding thing about floods in Brisbane is that they continue to take us by surprise.
Even the official Commission of Inquiry set up in the wake of the 2011 floods stated:
“The disastrous floods which struck south-east Queensland in the week of January 10, 2011 were unprecedented, in many places completely unexpected, and struck at so many points at once that no government could be expected to have the capacity to respond seamlessly and immediately everywhere, and in all ways needed.”
Yet there have been many examples of floods in Brisbane before 2011.
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In the 1973, the government approved construction of the Wivenhoe Dam on the Brisbane River, which proved its worth in 1983, when the partially constructed dam mitigated flooding which would have inundated Brisbane.
So what went wrong?
One possible answer is population pressure, and failure to adequately invest in improved facilities.
In 1983, Brisbane had a population of just over 1.1 million people. Today the Brisbane population stands at around 2.4 million.
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Head commissioner Catherine Holmes admitted there is no doubt that these floods took the state of Queensland, which is more accustomed to drought, by surprise. Referring to the final report, she added: “Anyone who is genuinely interested in how we manage flood risk will read it closely – all parts of it.”
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“A great deal can be done to improve readiness to deal with disaster generally, but it is impossible that any government could be permanently ready to come at once to the assistance of everyone needing help in a disaster of that scale and suddenness, unless it were to maintain a standing force of rescue personnel beyond the present capacity of society to fund.”
The commission hopes that this report and the interim report will serve as a detailed record for the future, of what happened in the floods and where things went wrong. However, it is in looking to the future and at longer term strategies that worries Holmes.
“Years of drought did not promote rigour in flood planning, whether in relation to disaster response, dam management or land use. Complacency about flood prevailed, at least in parts of the state, over many years,” she said. “And there is a risk that the recommendations made here will be enthusiastically taken up in the short term, but, absent another flood disaster in the next few years, priorities will drift and the lessons will be forgotten.”
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Read more: https://www.waterpowermagazine.com/features/featurequeensland-floods-the-final-report/
In the leadup to the 2011 and 2013 floods, after years of drought, dam operators were under pressure to ensure adequate water supplies to Brisbane’s growing population, and were very reluctant to release water.
The weather systems which caused the 2011 and 2013 floods could easily have missed the headwaters of the Wivenhoe dam. If dam operators had released precious water, and the storm systems missed, they would have been raked over the coals for acting too quickly and causing a water supply crisis. Only a direct hit had the potential to cause major floods. Anything else would have been a welcome capacity topup.
This reluctance to release water was not unreasonable. These storm systems are unpredictable. Just a few days ago, the Queensland government ordered schools to close, because a huge storm system was forming and threatening major disruption – then apologised for alarming people, after the storm system unexpectedly blew out to sea.
So what can be done to improve this situation?
In my opinion Wivenhoe’s original flood mitigation function has likely been compromised by Brisbane’s population growth. Dam operators are in an impossible situation, in which they have to choose between being fired for releasing too much water, if the storm system misses, or being fired for not releasing enough water if the storm system hits.
The obvious solutions are:
- Increase capacity of the Brisbane river dam system.
- Increase the capacity of other dams, and pipe water to Brisbane, to alleviate pressure to store too much water in Wivenhoe.
- Build new flood control channels or enhance existing channels, through some of the most expensive real estate in Australia.
All of these options would be expensive and unpopular. Any scheme other than increasing the capacity of Wivenhoe would face stiff opposition, from people who would be legitimately concerned that keeping millions of Brisbane voters happy would be treated by politicians as a higher priority than solving their problems.
Luckily the Queensland Government has a multi-billion dollar budget which could be cancelled and reallocated without causing disruption to any essential services – the billions of dollars in subsidies the Queensland Government currently hands out for building more solar energy capacity.
Whether the pressure to act this time will be sufficient for them to ditch their expensive and wasteful virtue signalling and build infrastructure people actually need, only time will tell.
I strongly recommend anyone interested in further analysis read Roger Pielke Jr.’s 2011 blog post on the historical perspective of Brisbane floods.
via Watts Up With That?
March 5, 2022 at 08:14PM
Iowa Climate Science Education 