FLOODPLAINS ARE PLAINS THAT FLOOD – SURELY THAT ISN’T TOO DIFFICULT TO UNDERSTAND.
Dr. John Happs
The recent flooding in Queensland has led to the not unexpected hand-wringing and wailing from the usual doomsayers including those green zealots who spread alarm about climate change, extreme weather and how any flooding in Queensland is the direct result of our trivial emissions of carbon dioxide.
Back in 2011 flooding in Queensland was declared the worst in 40 years with more than 26,000 homes impacted and, tragically, 16 people drowned. Green Party leader Bob Brown claimed that the coal mining industry was responsible and should pay for the Queensland flood damage. Seemingly unaware that major floods have always visited Queensland, Brown claimed that:
It’s the single biggest cause – burning coal – for climate change and it must take its major share of responsibility for the weather events we are seeing unfolding now.
Jonathan Green who hosts Sunday Extra on Radio National also displayed his ignorance of Australian history when it comes to fire and floods. He tweeted:
The fact is we haven’t always faced these conditions. Forests that haven’t burned for millennia are burning. Rivers are dying. The dry tropics are inundated. What logic suggests that we shouldn’t do what we can?
The self-appointed Australian Climate Council contradicted the findings of the Intergovernmental Panel on Climate Change (IPCC) by claiming that we are seeing an increase in the severity and frequency of extreme weather. Displaying his ignorance and using the infantile “carbon dioxide is pollution” rhetoric, the Council’s Martin Rice added:
Greenhouse gas pollution is warming the climate system, increasing the amount of water vapour in the atmosphere. This leads to heavier rainfall.
Consider the facts about the repeated flooding of populated areas in Queensland.
https://www.qhatlas.com.au/brisbane-floods-1893-summer-sorrow
People have always been drawn to flood-prone areas since the lands there are fertile due to the deposition of organic matter and the rejuvenation of soils. In Australia, as in many other parts of the world, the fertile soils of floodplains are farmed. Nourishment of soils by regular flooding of the Nile is well documented and it facilitated Egyptian wealth.
The flooding of the River Danube in 2002 caused by 2 weeks of continuous heavy rain, affected Russia, Slovakia, Poland, Hungary, Romania, Croatia, Austria, the Czech Republic and Germany, leading to total economic loss exceeding 15 billion Euros. Many people lost their lives and many said they had seen nothing like it in their lifetime. Had they looked up the history of floods in Europe and noted high water marks on older buildings, they would have seen that the 2002 floods were neither unusual nor record-breaking, as the flood record at Melk, Austria testifies.
Note the 1501 Danube record flood event:
Living close to rivers and coastlines once meant lower transportation costs with better trade and communication. For the smaller populations that were drawn there any risks due to flooding were considered worth taking because of the geographical advantages offered.
Today, transportation by road and rail have eclipsed that from coastal trade but has not resulted in floodplains being left completely to the farmers. As populations have grown around the world, more people are living in flood prone areas despite more than 500,000 being killed globally and more than 600 million displaced by floods over the last 30 years. Going back further, the 1887 and 1931 Chinese Yellow River floods killed millions of people. Bangladesh also suffers from frequent flooding of the Ganges Delta as a result of monsoonal rains and cyclones, leading to recurring economic disruption and loss of life.
http://coolgeography.co.uk/Alevel/AQA/Year%2012/Rivers_Floods/Flooding/Bangladesh/Bangladesh.htm
The probability that flooding will occur in the future is expressed as a return period. If the return period of a flood is 100 years, the probability of the flood returning in any 1 year is 1% but this does not mean the next flood will occur 100 years later, rather there is a 1% chance that it will flood in any year, irrespective of when the last flooding occurred. Floodplains are inundated at regular intervals yet, even those people who have experienced flooding, continue to go back to their homes in the hope that it will not happen again in their lifetime. It is a simple fact that floodplain settlements, having been flooded previously, will inevitably be flooded again.
In 2007 we were told that much of central and southwestern England was inundated by some of the worst flooding in “living memory.” The problem is that “living memory” is relatively brief.
Kocornik-Mina et al. (2015) highlights the problem:
In spite of their greater exposure to large flood events, we find that across the globe, urban economic activity, as proxied by night light intensity, is concentrated disproportionately in low elevation areas. This disproportionate concentration of economic activity in flood-prone areas is found even for areas that are prone to extreme precipitation.
https://www.researchgate.net/publication/295547796_Flooded_Cities
Expanding populations and commercial/industrial activities on floodplains provide a number of flood magnification factors. As more concrete is laid down, runoff increases. Changes in land use, water use and increasing urbanisation results in the reduction of floodwater storage capacity and a decrease in infiltration. Just the addition of a shopping centre and its associated parking area will markedly raise the level of the next flood.
And there surely will be a “next flood” in Australia since the eastern seaboard will always be at the mercy of El Niño (Spanish for “the Christ child”) and La Niña (Spanish for “little girl”) cycles that cause extreme weather such as floods and droughts. El Niño events are characterised by the collapse of the easterly trade winds and the movement of warm surface water away from the east coast of Australia to the central and eastern Pacific Ocean. The removal of warm water from the east coast of Australia results in less rainfall and increased drought conditions.
On the other hand, La Niña events are characterized by a strengthening of the easterly trade winds such that warm water at the ocean surface moves west to accumulate at the ocean surface in the western Pacific. This creates more moisture in the atmosphere, more clouds and more intense rainstorms for Indonesia and Australia’s eastern seaboard. La Niña events mean a high risk of flooding in Queensland.
The current La Niña event can be seen at the NOAA website:
https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml#current
The situation on 30th January 2019 is shown below:
Climate alarmists should look at Queensland’s history of floodplain inundation in 1841, 1887, 1889 and 1890. The 1893 flood was greater than those experienced previously and led to a government report warning about building on floodplains.
There was another major Queensland flood in 1908, followed by an extended flood-free period sufficient for the population to become complacent, to the extent that building and development on the floodplains continued unabated until the next (1931) flood. This event persuaded the government to build a dam to contain floodwaters. Work started on the Somerset Dam in 1935 but was held up when World War 11 broke out. Construction resumed in 1948 and the dam was finished in 1958.
Following the war and a relatively long period without a major flood, complacency descended again and residential building was resumed on floodplains. Of course there was the forlorn hope that the Somerset Dam would provide adequate flood protection anyway. It didn’t!
Cyclone Wanda struck the Queensland coast on the 24th January 1974 resulting in the largest flood experienced in the 20th century with the Brisbane River peaking at around 6.5 metres. 14 people lost their lives and the damage was estimated at 200 million dollars. Blame was levelled at land developers, the Bureau of Meteorology and the government.
https://www.history.com/this-day-in-history/cyclone-wanda-causes-flooding-in-australia
Wivenhoe Dam was completed in 1985 to provide water storage, hydro-electricity and flood mitigation. The government promised that Wivenhoe would prevent a repeat of the 1974 flood. It didn’t!
Climate alarmists have long insisted that the greatest problem facing Australia is a significant reduction in rainfall because of (imaginary) global warming. Politicians were persuaded by such pseudoscience and this led to the relaxation of planning rules in Brisbane and the continued building of homes in areas known to be vulnerable to flooding.
In 2007 Australia’s Dr. Tim Flannery foolishly predicted that global warming would reduce rainfall such that desalination plants would be needed to save Brisbane, Adelaide and Sydney. Politicians believed this and spent more than $1.2 billion on a desalination plant for Brisbane; $1.8 billion on a desalination plant for Adelaide and $1.8 billion on a desalination plant for Sydney.
In March 2010, the Wivenhoe Dam reached 80% capacity yet local politicians still told people to use water sparingly. After all, they had been led to believe in global warming and permanent drought. The dams became dangerously full and, when the Wivenhoe Dam was well over 100% capacity, water had to be released at the same time that floods were hitting Brisbane’s river system. Disaster inevitably followed.
Politician’s belief in the global warming/drying continent and the permanent drought nonsense failed to discourage the construction of more homes on floodplains or the early release of large volumes of dam water. Again, flash flooding destroyed many of those homes that had been built on floodplains.
Incredibly, Australia has scientists who promote the belief that flooding in Queensland can be controlled by reducing the pathetically small levels of carbon dioxide that enter the atmosphere each year. Clearly there are scientists (usually computer modellers) in Australia with vested interests. A number of these scientists are affiliated with the political/ideological Intergovernmental Panel on Climate Change (IPCC). They continue to exploit tragedies such as fire and flood to promote their alarmist carbon dioxide agenda and they are usually cheered on by the media.
It is verging on the irresponsible to use computer forecasts to formulate flood and bushfire policy. The climate models used by the IPCC and Australian modellers to make alarmist predictions of global warming incorporate only a few of the many variables that are known to affect the climate. The models are unvalidated and many of the values inserted for the variables used are little more than estimates, with the following inevitable results:
But even the alarmist IPCC UN IPCC 2001 Report (14.2.2.2 par 5) made clear:
In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that long-term predictions of future climate states is not possible.
Uncontaminated satellite and radio-sonde data do not agree with the alarmist computer model predictions that systematically give high predictions of global warming and such models should not be relied on as a basis for climate policy.
It would appear that the Australian poet Dorothea Mackeller (1885-1968) knew more about our climate than many alarmist scientists when she penned:
I love a sunburnt country,
A land of sweeping plains,
Of ragged mountain ranges,
Of droughts and flooding rains.
So how successful have Australian computer modellers been with their opinions and flood predictions? Not very!
In 2007 The Bureau of Meteorology’s Dr. David Jones emailed colleagues at the University of East Anglia:
Truth be known, climate change here is now running so rampant that we don’t need meteorological data to see it. Almost every one of our cities is on the verge of running out of water and our largest irrigation system (the Murray Darling Basin is on the verge of collapse…
In 2008 we had the BOM’s Dr. David Jones telling us that it might be time to stop describing south-eastern Australia as being gripped by drought and instead accept the extreme dry as permanent. He added:
Perhaps we should call it our new climate.
https://www.smh.com.au/environment/this-drought-may-never-break-20080104-gdrvg6.html
Except that, in 2008, Sydney had its wettest year since 1998, receiving 1499 mm of rain. This was well above the long-term average of 1215 mm.
Undeterred, in 2009 the Bureau of Meteorology’s Dr. Bertrand Timbal told The Age newspaper:
In the minds of a lot of people, the rainfall we had in the 1950s, 1960s and 1970s was a benchmark. A lot of our [water and agriculture] planning was done during that time. But we are just not going to have that sort of good rain again as long as the system is warming up…
Except in 2011 when it rained almost non-stop everywhere across Australia and not one city missed out on “that sort of good rain.”
Except in 2012 when another La Niña event produced heavy rainfall and flooding not seen since the period between 1950 and 1974.
In 2016 BOM modellers predicted this temperature for September :
Wrong again! In fact that winter was the second wettest on record with Perth shivering through its coldest September on record.
But the computer-driven predictions continued with the Australian Bureau of Meteorology (BOM) failing to predict the heavy rainfall that recently hit Townsville in Queensland.
On the 17th January 2019 the BOM confidently predicted that Townsville only had a 45% chance of exceeding its average rainfall. In fact Townsville received 4 times the monthly rainfall.
Early Queenslanders knew what to expect and they prepared accordingly. They elected to reside on floodplains and many of them elevated their homes to give us the classic Queenslander houses we still see today:
One thing is certain. Failed weather predictions will continue to haunt the Australian Bureau of Meteorology as long as they ignore natural cycles and remain obsessed with the trivial amounts of atmospheric carbon dioxide and their belief that this magically controls Australia’s weather.
Further reading: http://joannenova.com.au/2019/02/townsville-floods-again-1881-1892-1946-and-1953-itd-be-climate-change-if-it-stopped-flooding/
Dr. John Happs M.Sc.1st Class; D.Phil. John has an academic background in the geosciences with special interests in climate, and paleoclimate. He has been a science educator at several universities in Australia and overseas and was President of the Western Australian Skeptics for 25 years.
Now retired from academia and consulting work, Dr. Happs frequently writes to scientists, journalists and politicians, providing evidence-based information about climate change whilst exposing the ways in which the issue has become captured by politics and ideology. He has had one of his letters, detailing IPCC malfeasance, tabled in the Canadian Parliament. He gives regular talks on climate change to community groups such as Probus, U3A and Rotary since he believes that the public has essentially obtained its information about climate change through the media and political commentary.
An excellent article. A minor clarification:
I believe that this statement is slightly unclear:
“In March 2010, the Wivenhoe Dam reached 80% capacity yet local politicians still told people to use water sparingly. After all, they had been led to believe in global warming and permanent drought. The dams became dangerously full and, when the Wivenhoe Dam was well over 100% capacity, water had to be released at the same time that floods were hitting Brisbane’s river system. Disaster inevitably followed.”
The Wivehoe Dam officially has two ‘levels’, the ‘botttom 100 %’ being for drinking water storage, and the ‘top 100%’ being for flood mitigation. Due to state government concerns about low rainfall, it was allowed to reach about ‘180% full’ before the flood event, leaving little room (as planned) to safely store the flood rain. Thus the situation (repeated recently with Townsville’s Ross River dam?) came about that the critical flood mitigation function of the Wivenhoe dam was not available when (at long last) it was really needed due to massive and unnecessary ‘water hoarding’; and what is worse, they need to fully open the spillway near the height of the flood event to avoid damage to the dam by a massive uncontrolled discharge (again repeated in Townsville?) caused major downstream flooding of itself.
I read the government’s Wivenhoe dam management instructions at the time, which clearly stated that the dam water level should have been kept at or below the ‘bottom 100%’ level, in order to provide the ‘top 100%’ capacity free for flood mitigation during inevitable flood events.