Flooding rains have soaked south-east Queensland, again. My heart goes out to everyone affected by flood waters.
I’ve been watching the rain gauge at Lowood (Station# 040120), located just 10 kms to the south of Wivenhoe Dam upstream of the city of Brisbane.
A total of 240 mms fell yesterday (Saturday 26th February) which is a record for any one day since August 1887 when they began measuring daily rainfall at Lowood!
I feel I can finally use that word: unprecedented.
While the experts (remember Nicholas Stern) have been claiming it would get drier along the east coast of Australia, a few of us have theorized that it could get wetter.
The data for Lowood is interesting. Not counting this year, or this summer (because it is not yet over), the wettest year on record is 1890 with 1,445 mms and wettest summer is 2010-2011 with 987 mms.
But the totals for any one day appear to be increasing.
This is consistent with the idea that as the Earth’s temperature increases, from whatever cause natural or human, there will be increased evaporation over the oceans providing more energy for tropical convection that will result in more intense rainfall.
Drs Peter Ridd and Marchant van der Walt explain how this could result in a strong negative feedback mechanism that would counter the effects of increasing concentrations of greenhouse gases on global temperatures in Chapter 12 of my book Climate Change: The Facts 2020.
When the city of Brisbane last flooded back in January 2011, I thought that would be the end of it. Not the end of Brisbane, but the end of everyone obsessing over catastrophic human-caused global warming.
We had been hearing for some years about how the reservoirs would never fill will water again. How Australia’s were doomed to a thirty future. Then. Suddenly. Large parts of my city – including the entire downtown central business district – were submerged. Not from the rain directly, but from the emergency release of vast quantities of water from Wivenhoe Dam. A dam built for flood mitigation but kept too full of water because of a mistaken belief that it would not rain again: that below average rainfall is to be expected.
Again, as I write this from Noosa – 120 kms to the north – it is raining. It has been raining for three days; not pitter-patter, but rather torrents of rain with lashing winds, just like when Brisbane flooded back in January 2011.
I call Brisbane my city, because I went to boarding school there, and then returned, for my daughter’s schooling. We were there through the drought years before the flooding of January 2011. Back when human-caused global warming was becoming so popular, and many in Brisbane began boasting about how quickly they showered – to save water – because of the claimed declining rainfall across eastern Australia.
Except rainfall was never in decline if one considered the entire record, from the beginning.
It was the release of the report on climate change by Sir Nicolas and the British government in 2006 that more than any other event created the impression it was getting drier. The idea of an endless drought because the entrench myth after that.
Observational data on rainfall for the entire east coast of Australia is available from the Australian Bureau of Meteorology with yearly averages for all the sites back to 1900. Contrary to the Stern report, the data did not show declining rainfall; rather, it indicated that rainfall was very low in the early 1900s, that there were some very wet years in the late ’50s and early ’70s, and over all the trend was one of a slight linear increase to the release of that report back in 2006. Since then, it is even more absurd to claim declining rainfall.
Despite it not being honest to the available data, the Stern Report received rave reviews and an enormous amount of publicity around the world, and is still quoted.
I wrote something of a rebuttal regarding the rainfall bit – explaining that it would likely rain again, and then it would flood. My article was published as an opinion piece in the local Courier Mail newspaper causing my daughter to be embarrassed at school by the Principal.
The school principal came from reading my piece in the newspaper to confronting her with my opinions on climate change in front of her friends at lunch time in the playground. She had the good sense to tell the school principal that his behaviour was ‘inappropriate’.
It was like that: terribly politically incorrect to even suggest that the drought would end one day. It got people upset, and wanting to correct you, or to turn away because they knew the dams would never ever fill again. To suggest that we were going through just another cycle, as I did back then, was heresy.
And now Brisbane is flooding again. And water is being released from Wivenhoe Dam that was built for flood mitigation after the terrible flooding of 1974. That followed the floodings of 1968, 1951, 1947, 1931, 1927, 1926, that followed the floodings of 1908, 1907, 1893, that followed floodings of 1887, 1864, 1863, 1857 and according to some the very worst flood was in 1841.
The feature image is from January 2011, from Sandford Street near the University, St Lucia, Brisbane.
Lowood was one of the sites John Abbot and I used to test our capacity to forecast monthly rainfall, as detailed in the research paper entitled ‘Using lagged and forecast climate indices with artificial intelligence to predict monthly rainfall in the Brisbane Catchment, Queensland, Australia’ published in the Journal of Sustainable Development and Planning, Volume 10 back in 2015.
David Hounslow says
I am pleased you published the information about the Wivenhoe Dam. Keeping that FLOOD CONTROL dam filled until the water reached critical level and had to be released destroyed property and DROWNED PEOPLE. As you can see I am quite passionate about it and the fact that that fraud Tim Flannery still has a cushy job.
Allan Cox says
My rainfall stats recorded 626mm for February 2020.
Currently, my gauge stats show a total of 450mm to this time so, unless something really ‘climactic’ happens in the period until midnight tomorrow, Jennifer, I can’t match your ‘unprecedented’ rainfall here in my patch of heaven. 😊
Those of us more than ten years old will be more than vaguely familiar with South East Queensland “weather”.
Something in the back of my old brain thought it recognized a “sort-of” pattern.My (late) grandparents were very familiar with the S E Qld floods of the mid 1890s. Also the final separation of “North ” and “South ” Stradbroke Islands.
Wind, rain (lots thereof) and ocean currents and all that jazz.
I recall reading that there are solar cycles of approximately eleven years. 2022, 2011, 1999, 1974; it sort-of lines up.
I also recall (vaguely) reading about the role of solar PARTICLEs on rainfall patterns.
Now, allegedly, the big Nuke in the sky runs on cycles, approximately eleven years long. Hmmmm..
What’s a few weeks “drift” in the big scheme of things?…
So here I am on the north-ish ‘burbs of Briz-Vegas, watching the rain continue to tumble down… I’m on a slight saddle of a ridge. The soil is utterly saturated, with a puddle forming on the flattest piece of yard available. The soil is so wet that the rubble drains are overloaded and the downstairs bedroom carpet is getting damp.
That is nothing compared to having your ceiling filled with foul-smelling mud, as per Jindalee, et al., in 1974.
I was here for that one; getting around in big tip-trucks, shoveling peoples lives into the tipper as the rain kept falling, dumping that load, swinging by a blacked-out supermarket for bulk “freebies”, delivering them to the nearest Salvo Centre for “packaging” and delivering these “packages to relief centres. I was just a high-school kid among thousands of mad bastards who did this. Eccentric but super-organized elderly ladies who ran industrial soup kitchens out of anywhere that had functioning cooking facilities. like St’ John’s Cathedral.. Amazing times.
Flooding and dams. The average punter is not aware of S E Qld’s flooding history. Hence the recurrence of the term, “unprecedented”.
Post the 1890’s floods, the Qld Colonial government (pre-Federation) determined to build a serious dam on the Stanley river to prevent a recurrence. It was finally finished in 1959, about par for a government job. Some clever little Vegemite had noted that the Stanley is a BRANCH of Brisbane and started the ball rolling on what was to become the Wivenhoe Dam.
That dam straddles about the only “suitable” abutments for MANY kilometres an any direction. Not sure what it did to the lungfish population, ….
There is, of course, a catch; one which was revealed in 2011. Wivenhoe is a clay-cored rock-wall construction, with a vaguely conventional concrete flood-gate structure in the middle.
In the political shambles leading up to the 20211 flood, there was much official paranoia about water resources; hence the “grey-water” garden irrigation and reduced toilet flushing and general water use. That in itself led to “unintended” consequences. The “Rat Patrol” dogs of the various local authorities could not keep up with the action. Massively reduced water flow into the sewers turned l those pipes into rat freeways. It got better. The big pumps used to shove sewage around a lumpy place like Brisbane ran dry. There were, and probably remain, NOT self-priming pumps. Run them “dry ” and the bearings and seals will die, accompanied by VERY expensive noises.
So, when the rains finally came, and kept coming, SEQ Water held the line of NO releases from Wivenhoe. (the not-for-water-storage dam).. The water level steadily rose. The core of the dam is clay of a type called “smectite” used because it expands as it absorbs water. However, it has a very specific absorption / expansion rate. (SLOW). Thus, if the water rose faster than the clay core could do its thing, the water would start to flow THROUGH the billions of micro-fractures in the clay and actually start to erode the clay as it did so.. If someone were crazy enough to let the dam level rise to OVERTOP the clay core, then ALL bets were off.
So, as one has come to expect, the order was eventually, and reluctantly, given to open the flood gates. This was additionally motivated by the fact that the water was about to flow through the “emergency spillway” at the western end of the dam wall. In the spirit of Murphy, the eternal optimist, this coincided with the vast amounts of water from the Lockyer valley hitting the main river channels DOWNSTREAM of the dam.
Another interesting feature of Wivenhoe is the “emergency spillway”. This is part of the “extras” built into the dam. It WAS supposed to be pre-drilled for explosive charges, so that, in the event of a seriously rapid rise in water level, a big chunk of rock could be made to go away, thus allowing a lot of water to rush downstream. There would be flooding, but at least the entire city of Brisbane would not end up at the bottom of Moreton Bay.
The whole rock-show was a near-run thing. Brisbane STILL sucks its water from a dribble of river near Mount Crosby and there is NO margin, anywhere in the system.
Your taxes at “work”. .
I am NOT a hydrologist etc,; I barely made it out of high-school alive. But I have eyes and ears.
Dave Ross says
As some would know, Wivenhoe Dam was built as a water storage facility for a growing SEQ population and was designed with an additional “flood mitigation” compartment.
It was never designed to prevent a Brisbane flood as many believe.
That is impossible as about 50% of the Brisbane River catchment enters the river below the Somerset and Wivenhoe Dams.
Major contributors below the dams are the Bremer River and Lockyer Creek plus many large, well known overland flows which cannot be controlled.
At the peak of the 2011 deluge, water was entering Wivenhoe at a rate representing a volume of total storage + flood compartment every 23 hours.
And despite all this the maximum flood level reached at the Port Office was about 1 metre lower than the 1974 level.
The much maligned engineers trying to control the flood event should have received acclaim not the condemnation of the ill informed.
Jennifer Marohasy says
Dave Ross. It was built after 1974 specifically for flood mitigation.
Dave Ross says
Yes I know very well when it was built but with a capacity for flood mitigation, not prevention as I pointed out.
The dam was designed as a dual purpose facility with a drinking water storage capacity of 1.16 million megalitres.
A further 1.967 million megalitres or flood mitigation compartment was provided.
And it worked.
In 2011, the Brisbane River flood remained one metre below the maximum reached in 1974.
That some of the flood mitigation compartment had been filled prior to the deluge is a matter of record and to say that the dam was kept full because of the belief that future rain would be in short supply possibly has some truth to it.
The volume of water in the flood mitigation compartment proved to be insignificant and in the 25 days prior to the massive flood event three small flood events impacted on Wivenhoe Dam with gate releases being made on all but five of those days.
The total outflow from these events was around 700,000ML.
Not widely reported.
I am quoting from the SEQ report submitted to the Floods Commission.
“significant drain down prior to the current event would have had little impact on the
peak level in Wivenhoe Dam as shown in the table below. The reason for this is that this total event inflow volume of 2,600,000 ML is well in excess of the useable flood storage combined with the available water supply storages shown in the table”
And from the Flood Commission presided over by Justice Catherine Holmes.
“even a large dam such as Wivenhoe has a limited flood mitigation capacity when the volume of water entering it is significantly larger than its storage capacity”.
“Its flood-mitigation effect for Brisbane was further limited by the fact that floodwaters from other parts of the Brisbane River catchment entered the river downstream of the dam, through the Bremer River and the Lockyer Creek.
“The flooding in Brisbane and Ipswich could have been reduced to some degree had the dam had its capacity reduced to 75 per cent prior to the December rains, but to appreciate what the magnitude of the rain would be and that it would fall in the dam area would have required a more than human capacity of prediction.”
I feel for your daughter being called out by that teacher. It happened to me similarly. I think for an “educator” to do that is a horrendous offence and deserves a custodial sentence
Frances Lilian Wellington says
Re: “more than human capacity for prediction”.
As a postie I watch the BOM rain predictions shift as they are updated each day. It is not uncommon to actually receive 10X the predicted maximum. And the opposite, just a week ago before this deluge it was predicted (on the day) to be above 90% chance of rain all day, up to 20mm yet it was pretty dry all day across Brisbane. Not even 2mm.
With these BOM anomalies it’s no bloody wonder that dam levels can’t accurately be predicted ahead of time. Dam operators require accurate predictions from BOM (just as I do as a suburban postie). If BOM can get their predictions right more often then everyone will benefit. But how can they? When what is required is more than “human capacity for prediction”. Let’s not kid ourselves. There are limits to our capabilities.
I’m not sure about the current flooding, but back in 2011 the setup across the Pacific very clearly showed we were in for an exceptionally wet summer. The SOI was very positive, about +21 from memory in November or December 2010.
Yet SEQ water choose to keep Wivenhoe full of water. A dam that was built for flood mitigation. It was lunacy, as the Ipswich mayor pointed out at the time/some months before the flooding that occurred in January 2011.
At the time Anna Bligh was Premier and Tim Flannery was commissioner of something and they were lecturing us on concept of endless drought. They were so consumed with the myth of catastrophic drying they couldn’t contemplate the idea of flooding.
As regards capacity for weather forecasting, we know that the skill of the Bureau when it comes to seasonal forecasting is in decline because it relies on simulation modelling and a failed paradigm. The first chapter of my book CCTF2020 details some of this. You can read it here: https://climatechangethefacts.org.au/introduction/
It would be better if climate science instead move to the use of artificial intelligence and neural networks as detailed in the paper I reference: ‘Using lagged and forecast climate indices with artificial intelligence to predict monthly rainfall in the Brisbane Catchment, Queensland, Australia’ published in the Journal of Sustainable Development and Planning, Volume 10 back in 2015.
Forget about the ‘human capacity’ for prediction, and move to AI and large data sets and super computers and underpin that with an understanding of the cyclical nature of drought and flooding along the east coast of Australia. Cheers,
Graham Young says
You sold your house at Chelmer just in time. Thanks Graham. 😉
Dave Ross says
I remember that narrative from the doom drummers.
Peter Beattie, when trying to justify the fatally flawed, Traveston Crossing Dam proposal, even said he didn’t want people “dying of thirst” !
But my point is, that Wivenhoe Dam is just not big enough to be an effective flood mitigation facility when extreme events come around.
And if it was built specifically as a flood mitigation dam it wouldn’t have a drinking water compartment – the engineering literature describes it variously as a multi-purpose dam, a dual purpose dam etc.
It is Brisbane’s major source of drinking water.
Again from the Floods Commission;
“whatever the source of the apparent popular misconception that Wivenhoe Dam would contain all floods emanating in the upper Brisbane River, it is certainly not any of the engineering investigations conducted in connection with the dam during the past four decades.”
“It is trite to say, yet important to note, that the capacity of flood mitigation dams to contain floods is subject to the volume of rainfall experienced in the dam’s catchment. The ability of operators to manage a flood is very limited when the volume of rainfall run-off greatly exceeds the volume of the available flood storage within the dam.”
That the dam should have been in a better state of readiness in 2011 considering the SOI and other data is also beyond question and the Commission recommended in future that the Wivenhoe drinking water compartment is kept at no more than 75%.
This time around the DWC was at 59% meaning the flood mitigation compartment was empty.
We don’t know yet what the relevant inflows/outflows have been to make an apples with apples comparison, although it appears the Bremer, Lockyer Valley contribution may have been less than 2011 – but major flooding is now in play in Brisbane as we type although at a lower level so far than 2011.
Meantime I’m stuck on the wrong side of the Mary and unable to get to Brisbane Airport and fly to Fiji, where I was to take up and complete a desalination project we started two years ago.
David Hounslow says
I humbly stand corrected and now realize the 11 year flood cycle is beyond mankind’s ability to control. It may be necessary to clear and depopulate areas that flood every 11 years despite their attractiveness in intervening periods.
Dave Ross says
Depopulating flood prone areas has been raised many times as far back as January 1974, when ALP vice president Jack Egerton called for all flood prone areas to be resumed by the State Government and made into parks, sporting fields etc and never to be zoned residential again.
Predictably, property developers didn’t agree.
Another engineering/economics study, that I can’t find at the moment since my new hard drive was installed, published post 1974 flood recommended the same.
Which raises some good points.
Why are some areas zoned as residential when they are well known to be flood prone in extreme events ?
Rates are super expensive in many river front properties.
Maybe that is the answer.
And if you build on a flood plain, you are gunna get flooded eventually.
We know that there have been massive floods up here in the Mary Valley much bigger than the 1893 record level according to geologists looking at sedimentary deposits.
Wivenhoe Dam, properly managed, definitely mitigates floods for the Brisbane area, but to what extent depends on the rain gods.
As engineers have been pointing out since the dam was originally proposed and designed.
Major floods will still occur – Wivenhoe is just too small to prevent them – massive but too small during major rain events which, as Jennifer points out, are odds on to occur again.
In 1893, three major events occurred in a month – Wivenhoe would be sorely tested in that event and there is nothing to say that can’t happen again.
With the fear of continuing drought, the Wivenhoe pipeline was built to Toowoomba at great cost to Qld. taxpayers and Toowoomba rate payers; project completed Jan. 2010. Then the drought broke January 2011.
David Hounslow says
Most young people believe by attempting to go solar and stopping the burning of carbon based fuel all climate difficulties’ will be solved but unfortunately we cannot control the Suns output so drought fire and flood will continue.
Allan Jorgensen says
I love reading historical journals, books etc.
I vaguely remember Andrew Petrie (early SE Qld settler) writing about his discussions with local Brisbane indigenous peoples about a flood of the Brisbane River that left Spring Hill as an island.
Perhaps someone could look follow that up.
You can learn a lot by reading such literature.
For instance at Cairns Hospital I found that historical records showed flooding to a depth of 3 feet at the Hospital location. The Hospital’s emergency generators were up at top of building but then fed down to the main switchboard at ground level so that in event of similar flood we would have lost the whole hospital. I quickly arranged to have the main switchboard lifted up to first floor level.
Just filing this here:
The weather bureau’s constantly changing forecasts about the duration of the “rain-bomb” that hit south-east Queensland highlights the unpredictable nature of the event, Premier Annastacia Palaszczuk says.
Despite similarities to the 2011 floods with thousands of homes inundated in Brisbane, Ms Palaszczuk said there was little more the State Government could have done to lessen the damage in the city due to the extreme conditions.
“This was an unpredictable event, an unpredictable rain bomb over the entire south-east Queensland,” she said yesterday.
“No-one could have foreseen that in the three or four days, and in some areas, you got one year’s worth of rainfall in one to two days.”
Asked whether the flood-mitigating Wivenhoe Dam should have been emptied before the deluge — based on BOM forecasts — she said the bureau’s predictions had been different three days in a row.
“On Thursday the [Bureau of Meteorology’s] information was that on Friday, conditions were easing, and then it changed on Friday, that conditions were going to be easing on Saturday, then they didn’t ease, then the conditions were going to be easing on Sunday,” she said.
“So this is what we have had to be dealing with, a rapidly evolving situation.
The BOM has been contacted for comment.
Seqwater’s external relations manager ike Foster said the agency only made decisions around “rain on the ground” not weather forecasts.
“We absolutely work with the Bureau of Meteorology in relation to weather forecasts,” he said.
“The way we do that, and we do modelling on rainfall forecasts to tell us where an event may go, but when we make decisions we want to make decisions around as much certainty as we can.
“And we make decisions around rain on ground and how much inflow we are going to get into our systems, and we can model that and that can tell us where our dam levels are actually going to go.”
Murray Webster says
Very sensible Jennifer.
A couple of points which I think indicate that the data we have is of unknown reliablility.
1. Flooding events are influence not only by rainfall. Features of the catchment that change over time also influence flooding by slowing the rate of runoff and increasing the time taken for water to accumulate further downstream. Swamps/wetlands 150 years ago, where scattered all around the catchment, probably maintained by Indigenous burning. They soak up huge amounts of water during rainfall events, and release it slowly during dry times*. Our agricultural practices (including my uncles/grandfather and farmers I knew) dictated draining swamps. This causes increased concentration of water in shorter periods of time, gully erosion, and faster concentration of water downstream, so, higher flood peaks. Other vegetation around the catchment also affects run-off rates.
* for good news on this, see https://themullooninstitute.org/ ; the only property near Bungendore that was able to supply water to bush fire trucks during 2019/20 fires.
2. How reliable can historic rainfall figures be? The recordings stations are very small in number compared to the extent and variability of rainfall events, and they located with bias towards human settlements so are nowhere near a statistically robust sample. Additionally storms are so hugely variable. E.g. a few weeks ago, West Gosford and Narara had hail, very heavy rain, and wind that damaged some roofs. Kariong, up the hill a few km away got nothing. And the Gosford BOM weather station was not in the path of the storm either. No data was recorded. This is the nature of storms and the data we have available is totally inadequate for statistical inference.
Australia has always been land of drought and flooding rains, as observed by Dorothea McKellar in 1908.
“I love a sunburnt country,
A land of sweeping plains,
Of ragged mountain ranges,
Of droughts and flooding rains…….
For flood and fire and famine
She pays us back threefold.”
The drought usually breaks with a flood. The cycle of drought and floods is illustrated in Jennifer’s graph. The problem is that people like to live near rivers, and forget about floods. It was quite astonishing to see the value of riverfront properties in Brisbane soar, just a few years after the 2011 floods.
spangled drongo says
Jen, it was good to see that the people currently in charge of flood control at Wivenhoe were paying attention this time, unlike 2011 when there was nobody home until the dam was about to blow the fuses and they had no option but to dump the lot on those poor 28,000 homes who, 11 years later, are still waiting for justice.
You mentioned comments of prolonged droughts by Stern and others. However you didn’t mention that the El Nino of the preceding 10 yrs had switched to a La Nina well before 2011.
All the Western Corridor Recycled Water Scheme was not required from about 2009 about just when it was completed, because of the La Nina rains.
Plus you seem to be stuck on Wivenhoe being purely for flood mitigation, when it was not. It was thus neither optimal for mitigation nor water supply.
Don Gaddes says
Still mired in the fantasy of ENSO????….
I point out the proximity of the large Tongan eruption,(heat source) to this flood event….
Robert Gilliland says
Allan, I have heard a similar story in Gympie where the local indigenous people said the hospital hill was also like an island in a sea of water. Probably happened at the same time.