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More on Brisbane floods

Casting around for someone to blame for the Brisbane floods continues and there is an excellent article in the Australian considering the issue of whether the Wivenhoe damn should have been emptied earlier (H/T Aynsley Kellow, in the comments). There is a fairly damning quote from a local hydrologist:

When they finally did release [water from the dam], it was because they had received so much inflow this week that they were afraid the whole system would collapse. There is no doubt in my professional opinion that most of the flooding in Brisbane should have been avoided. It is extraordinary to me that people are not asking more questions about this. Brisbane should have been protected by Wivenhoe Dam. Instead, the dam is a large part of the reason the city has flooded.

There is also, however, this word of caution from an engineer who was involved in the dam's construction:

"These questions are all valid, but put it this way - you would have to have very large balls to [significantly reduce the dam's volumes in the months after the weather warnings] after 10 years of drought, because if you had got it wrong you would be accused of wasting the water" 

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Reader Comments (91)

This part of the editorial by The Australian

There is nothing people can do to stop rains, generated by the La Nina weather pattern on the east coast, which are part of a natural cycle we are only beginning to understand. But nature need not dictate the way we respond. In Queensland, an army of volunteers turned out on the weekend to help flood victims. Across the country communities stood together against the threat, with volunteers reporting for duty as they do for every fire and flood. In contrast, Greens leader Bob Brown was scoring points yesterday, claiming burning coal is a major cause of global warming, which leads to high ocean temperatures and the floods that follow. He said this meant coal producers should have to pay for future floods through the tax system. But La Nina is not man-made, and linking global warming to flooding is a bridge too far. It was also irrelevant to the mood of the country at the start of Queensland's recovery. Most affected Australians were out helping each other yesterday, rather than looking for somebody to blame for a natural disaster.

Jan 16, 2011 at 7:03 PM | Unregistered CommenterMac

Another report that says that Australia will both get drier and wetter.

Note the comments - Premier Ted Baillieu said he was open to new dams helping with flood mitigation.

Jan 16, 2011 at 7:23 PM | Unregistered CommenterMac

I don't disagree with your basic analysis, but the question remains as to whether the water supply storage would ordinarily be full at the beginning of a wet season, and whether it should be kept at that level - especially when a severe La Nina has set in. I think the problem is the mindset of the decision-makers, especially with a long drought in recent memory and a desal plant with a relatively high avoided cost in the equation - and various recycling options being considered (at least by researchers).

With a network linking dams and a strong La Nina, I'd be running down the storage (discharging through the hydro generators at peak periods to maximise electricity price in the market, and thus revenue) in the spring, secure in the knowledge that it would be recharged by the end of the wet season. This strategy would not be dependent on where any one rain depression dumped its load.

Again, however, I make the point that the low quality 'projections' of regional climate change in the long run (forecasts with little to no skill) have been preferred over those of the seasonal weather forecasts of ENSO which do have greater skill.

Jan 16, 2011 at 8:14 PM | Unregistered CommenterAynsley Kellow

Incidentally, more critical analysis here this morning (AEDT):

Jan 16, 2011 at 8:23 PM | Unregistered CommenterAynsley Kellow

O'Brien's report does not seem to be linked in the above story, but a copy has been posted by Andrew Bolt. Text follows.

What went on in Brisbane?
Was this a natural disaster or a manmade disaster?
First a bit of a disclaimer – I am new to some of this river data and may not have interpreted it all
First a bit of background: -
• Somerset Dam has a Water Storage capacity of 379,849ML with an additional 524,000ML for
flood storage. The dam is rated as 100% full when all the water storage capacity is full.
Therefore when both the water storage capacity and flood storage are fully utilised, the dam
would be at 238%.
• Wivenhoe has a Water Storage capacity of 1,165,238ML with an additional 1,450,000ML for
flood storage. Similarly when both the water storage capacity and flood storage are fully
utilised, the dam would be at 224%.
• Somerset is upstream of Wivenhoe and flood flows from Somerset are discharged into
• There is a river height monitor at Wivenhoe Dam: -Station Number: 540177 Name: Brisbane
R at Wivenhoe Dam Hw # Owner: SEQWCO:143822

SEQWater operate a web site which gives levels in all dams, including Somerset and Wivenhoe;
but interestingly, levels for Wivenhoe and Somerset were not updated between 08:00 11th
January and 09:00 13th January during the peak of the emergency. Historical data now
shown for this period on the SEQWater web site does not show any peak during this period and so
are obviously incorrect.
I have therefore used the Wivenhoe Dam river height monitor as a proxy for the dam level during
this period. There are some interesting disconnects between the river level data and the reported
water levels in Wivenhoe: -
Information from media reports had Wivenhoe at a peak of 191% overnight for the night of
11th/12th; but generally at 190% through most of the emergency period.
The river height shows a height of 73.77m at the time SEQWater were reporting a Wivenhoe
capacity of 175.9%. The river experienced a minor peak of 74.51m commencing at 14:57m
Tue 11th falling substantially (to 74.19m around 17:45 Tue 11th) until peaking again at
74.85m between 18:00 and 19:23 on Wed 12th (compared to a reported peak in Wivenhoe
during the night of 11th/12th). The river level fell gradually, and has continued to fall, from
this peak.
The sequence of events for the current flooding event seems to be: -
• 06:30 Tue 04th, Wivenhoe first went above 100% (i.e. using the flood storage capacity).
• Wivenhoe was at 106.3% at 06:00 on Fri 7th; but there are no reported heights for Sat 8th or
Sun 9th.
• Wivenhoe continued to rise, and at 09:00 on Mon 10th it was at 148.4% and it was reported
that “managers scrambled to increase the release from 116,000ML to 170,000ML per day.
• At 0800/0900 Tue 11th Wivenhoe was at 175.9%, Somerset at 160.8%; total available
capacity for flood storage in both dams stood at 858,642ML. This is the last available data
from SEQWater. At this stage the River height at the dam was 73.77m.
• The river (and by assumption the Wivenhoe dam) continued to rise over the next six hours
and reached an interim peak of 74.51m at 14:57 Tue 11th.
• At this time the river level started to fall quickly to 74.19m around 17:45 Tue 11th
• Media reports indicate that the discharge from Wivenhoe was increased from 344,00ML/d
through 490,000ML/d (both reported by the Courier Mail) to an overnight peak of
645,000ML/d (reported in a media release by the Queensland Police Service).
• SEQWater reported that at 0730 on Wed 12th the releases from Wivenhoe were reduced
temporarily to 215,000ML/d to allow Lockyer Creek peak to enter Brisbane River and would
subsequently be increased to maintain a maximum flow through Moggill of 301,000ML/d.
Some additional data: -
• SEQWater report that there is a delay of approximately 36 hours between a release at
Wivenhoe and a peak at the Brisbane City Gauge.
• It is likely that the rapid drop in the river level at Wivenhoe commencing around 14:57 Tue
11th was due to a substantial increase in the discharge rate from Wivenhoe (645,000ML/d?).
• At around the same time, 16:03 on Tue 11th the Courier Mail reported that Wivenhoe was at
190% and Somerset at 176%, indicating a total capacity for additional flood storage of
• 36 hours from 14:57 Tue 11th is 02:57 Thu 13th which corresponds almost identically with the
peak of 4.46m experienced at the Brisbane City Gauge.
Now for an attempt at interpretation of this sequence: -
• SEQWater were very slow to respond to the initial increase in levels at Wivenhoe and took 6
days before there was any real increase in rate of release from Wivenhoe to return the dam
to proper flood management levels. Even though there is apparently a legislated
requirement to manage this over 7 days.
• SEQWater then substantially over responded during the afternoon of Tue 11th increasing the
discharge to 645,000ML/d(?). This was at a much higher rate than the current water inflows,
resulting in a substantial drop in the level in Wivenhoe. This was even though there was
approximately 636,000ML of capacity available for additional flood storage in Wivenhoe and
• This substantial increase in the discharge from Wivenhoe was the cause (sole cause?) of the
peak in the Brisbane River.
• Early on Wed 12th (07:30), SEQWater recognised that this discharge rate was excessive and
reduced it substantially to 215,000ML/d. This discharge rate has been sufficient to ensure
that the river level at Wivenhoe (and presumably the dam) did not continue to increase and
indeed has allowed the level to gradually fall.
• Hindsight is a wonderful thing; but there are really two decisions that were taken which
would seem to have little justification at the time they were made. These are: -
o Not increasing releases from Wivenhoe between the 4th and the 10th when the dam
levels were rising and there was no downstream flooding, and
o The decision to substantially increase the discharge rate from Wivenhoe to a peak of
645,000ML/d on the afternoon/night Tue 11th.
• It is difficult to understand the justification for this increase in the discharge rate, especially
as the decision was substantially reversed within about 12 hrs. In addition even if SEQWater
had released at the low rate of 215,000ML/d (which is the rate it was reduced to at 07:30
Wed) rather than a maximum rate of 645,000ML/d for the whole time from 14:57 on Tues it
would have used only 306,000ML of the available free capacity in both dams of apparently
The serious questions are: -
• Why did SEQWater not allow the total available flood storage capacity of Wivenhoe to be
utilised during this period?
• What justification was there for the substantial increase in discharge from Wivenhoe to
645,000ML/d when a release rate of 215,000ML/d has been demonstrably sufficient to stop
the levels in Wivenhoe rising and while there remained substantial capacity in Wivenhoe for
additional flood storage?
• Was this increase to 645,000ML/d the sole reason for the significant flooding in Brisbane?
• Why did it initially take SEQWater 6 days to respond to the gradually increasing water levels
in Wivenhoe which reduced its flood control capacity?

Jan 16, 2011 at 8:38 PM | Unregistered CommenterAynsley Kellow

Dr Kellow

Do you perchance, have any details on the timeline of the Queensland Cloud Seeding Trials 2007-2011?

More specifically, is there knowledge of the last seeding runs this year and whether silver iodide was being used, or whether any ground salt was used at all?

Jan 16, 2011 at 9:30 PM | Unregistered CommenterShub

Found part of the answer: Silver iodide and ground salt was/is being employed.


Jan 16, 2011 at 10:05 PM | Unregistered CommenterShub

Shub - I was about to answer in the negative, but hit the delete button in error! I see you have your answer.

I note that Jennifer Marohasy has a reminder of an old post by Stewart Franks, who predicted all this back in early 2009.

Seems he is a cut above the AGW crowd in forecasting skill. Actually seems to be able forecast one or the other BEFORE the event, which is novel.

Jan 16, 2011 at 10:11 PM | Unregistered CommenterAynsley Kellow

Could prove much more useful than the Abbs papers:

The historical record of climate variability suggests that we should expect a return to a 20-40 year period where La Nina dominates the climate of at least eastern Australia once more. The observation that many regions of Australia routinely experience multi-decadal variability of flood and drought, suggest that we should expect a return to major widespread flooding on a regular inter-annual basis, and for entirely natural reasons.


Whether we can predict climate on multiple timescales usefully or not, we should certainly be preparing ourselves for both ends of the spectrum of climate extremes at all times.

Jan 16, 2011 at 10:24 PM | Unregistered CommenterShub

When is a La Nina not a La Nina?

When it is associated with droughts in Australia!!!!!!!!!!!

"La Nina behind Australia's drought", Thursday, 1 November 2007

Australia's long-running drought is linked to an unprecedented climate pattern that has taken hold in the Pacific basin and Indian Ocean, the UN weather agency says.

The World Meteorological Organization (WMO) confirms that a "very clear" disruptive La Niña event is under way across the equatorial Pacific Ocean, in line with its forecast in July.

It signals that the event is associated with "climate-related risks" that need to be assessed locally in different regions around the world.

But this year's La Niña differs by producing cooler than normal sea temperatures off northern Australia and Indonesian islands, the opposite of what was expected.

It is also, unusually, combined with separate sea surface temperature shifts in the Indian Ocean.

"The drought that's going on in Australia right now is a very serious drought and it is one of the atypical situations associated with this particular La Niña event," says WMO climate specialist Dr Leslie Malone.

"The textbooks would have said that Australia would have had a problem with more precipitation than they could handle rather than less," she says, underlining that the current La Niña is atypical.

La Niña usually combines tropical wind patterns over the Pacific basin with cooler than normal sea temperatures off the west coast of Latin America and warmer sea temperatures in the western Pacific.

Like its Pacific sibling El Niño, it is widely credited with disrupting weather even further afield.

Malone declined to be drawn on other disruptive effects of this year's event but says the agency is issuing an update because there is "an evolution with consequences for people around the world".

"Even in a moderate event there can be severe related impacts somewhere. What is difficult to say is where," Malone says.

New to science

Asked if this year's combination has been seen before, Malone says: "Since this is such a new pattern recognised in the scientific research community, probably not."

She emphasises that scientists are unable to clearly tie it with climate change.

La Niña is expected to continue into the first quarter of 2008.

The WMO warned in July that La Niña was shaping up in the second half of 2007, with the potential for disruptive impact "of planetary scale".

Its scientists have also linked the pattern with unusually broad and heavy seasonal floods that recently affected people from East to West Africa.

The WMO is trying to build a global consensus of scientific opinion on the pattern and impacts of La Niña and El Niño.

"Before we can all sing together, we need more research," says Malone.

Jan 16, 2011 at 10:25 PM | Unregistered CommenterMac

Stewart Franks seems to have a good handle on this and deserves more attention, both for his point that we should be trying to forecast wet periods, rather than assuming 100-year flood might occur any one year or the next, and for his point about ENSO being overlaid by other cycles. Jennifer Marohasy's summary of his theory is this:

Stewart Franks, a hydrologist at the University of Newcastle, has shown that the usefulness of the El Nino/Southern Oscillation (ENSO) as a predictor of flooding depends on whether or not a more complex phenomenon also measured by sea surface temperatures known as the Interdecadal Pacific Oscillation (IPO) is in a positive or negative phase.

In a series of peer-reviewed papers published in the best international journals since 2003, Professor Franks has shown that when the IPO is negative, as it was from 1946 to 1977, then there is a much greater chance that there will be flooding rains if a La Nina forms.

The IPO started to go negative in 1999, but an El Nino formed in 2001, and seven years of mostly drought followed – sustained by the El Nino conditions.

In February 2009, Professor Franks commented at this weblog that the Australian climate showed signs of entering another wet phase and warned that governments should prepare for a return to a 20-40 year period where La Nina dominates.

Just over a year later, in April 2010, the negative IPO now entrenched, a strong La Nina began to form and flooding rains followed.

Indeed the explanation for the recent devastating flooding is not carbon dioxide, but inadequate infrastructure and warning systems in the face of a combination of La Nina conditions during a negative IPO, a monsoon trough and already saturated catchments.

Franks has been largely ignored, as far as I can tell, by the AGW community, but his theory seems to fit both the past and to have predicted the future - explaining why the 2008 La Nina did not amount to much, but why the next one (2010-11) would.

I would never close my mind to any causal explanation including CO2 forcing - though the 'settled science' there still suggest to me that we have had most of the AGW a doubling of CO2 will give us (without some heroic assumptions about positive feedbacks). If the scientists can just get past the politically preferred problem definition, we might get to some decent understanding of the complex world of climate variability.

Jan 16, 2011 at 10:59 PM | Unregistered CommenterAynsley Kellow

Aynsley@8.23 & 8.38pm,thanks for the link to the Australian piece,citing Michael O'Brien. It unfortunately repeats the falsehood that dam managers released 645GL in a day as a panic move. The 645GL/day is a TRANSIENT peak flow figure.The actual release for the 24 hours was a more like half that from estimates using hourly volumes from downstream gauges.

I think O'Brien if anything slightly overestimates weekend releases at 200GL,but we must remember that releases were incrementally increasing as inflows increased. Extrapolating conservatively from Qld DERM data,I estimate mean daily dam release volumes at 65GL for Saturday 8/1,over 100GL for Sunday 9/1, 140GL on 10/1, 250+GL on 11/1 and 350+ GL on12/1. These are for 24 hour periods to midnight.

You might ask ,why not more? Lockyer Creek,entering immediately below Wivenhoe, was in flood adding an estimated 300GL over the 10-11-12/1,and the Bremer River was in similar spate.

Jan 17, 2011 at 2:04 AM | Unregistered CommenterNick

Aynsley, the ENSO/IPO connections Franks commented on have been established and explored in the literature in the last two decades,in papers such as 'Inter-decadal modulation of the impact of ENSO on Australia' Power et al 1999.

Jan 17, 2011 at 2:21 AM | Unregistered CommenterNick

Someone called Hopfrog responds to Germaine Greer's piece in the Guardian and has some very interesting (insider?) views of the Brisbane City Council (ie: it has already arrived at where the UK is heading):

"- Brisbane City Council has been far too preoccupied with important things like designing new fines to prosecute people's lifestyle choices like smoking outdoors.

- The council have been very busy up until the last few weeks with water patrols around suburbs hoping to catch people and fine them for using hose pipes against restrictions still in place since the drought a few years back! [the council's own literature boasts that its punitive measures had been instrumental in "saving 1.5 billion litres of water in the two years to July 2008, this initiative cut carbon dioxide output by an estimated 43 million kilograms"]

- At the same time [Brisbane Council] were hacking up CBD streets for hundreds of hire bicycles to 'green the city'...which nobody uses because most of the hills throughout the city require olympic fitness in sweltering heat and or driving rain..oh and no one just happens to ever carry a bike helmet incase they want to hire a bike...the cops fine you $75 if caught on a bike without one.

- when people were getting out of [flooded] Toowoomba by road, the cops were out too not directing traffic or ensuring public safety but hiding in the rain behind parked vehicles and lamp posts with speed guns clocking people making haste to safety.

- Just before xmas the the local council opposition leaders biggest concern was the fact only 300 people or so had been fined for smoking in the city's streets [...] and the council leader seemed embarrassed by this 'paltry figure' and ensured us all they were doing their best to enforce the regulations.

- for over a year now there's been opportunities to ease off dam pressure by letting the population do what they wish with the water. But no they have enjoyed the social control in keeping restrictions in place and nannying/bullying to conform to some sentiment of 'conserving every precious drop' and revenue raising with fines."

One guy's take... or a postcard from the Green future?

Jan 17, 2011 at 2:25 AM | Unregistered CommenterPeter S

Bigg, E. K., Enid Turton, 1988: Persistent Effects of Cloud Seeding with Silver Iodide. J. Appl. Meteor., 27, 505–514.

A statistical examination of precipitation records in and near areas where cloud seeding experiments have taken place in Australia strongly suggests the delayed effects of seeding. The most conspicuous effect is an increase in precipitation 1 to 3 weeks after a seeded day, which would have caused the conventional statistical estimates of success to have been misleading. Through comparison with earlier findings and some observations of prolonged increases in ice nucleus concentrations following the application of silver iodide to the ground, it is argued that secondary ice nuclei are involved in the persistent effects of seeding. If this is so, then they must have been more effective in enhancing precipitation than the silver iodide, itself; this leads to the possibility that there may be better ways of stimulating precipitation than those used so far.

Jan 17, 2011 at 2:26 AM | Unregistered CommenterShub

Thanks Nick. I think what stands out is Franks' forecasting skill using this approach - that and the suggestion that water management should not proceed as if the probabilities are randomly distributed. I am sure the flood managers in Brisbane probably followed their rules as best they could, but it was quite clear this was never going to be an average year. The real problem was keeping the water restrictions in place above the initially promised 60% level, when they were supposed to be removed. Why? Because the Premier said water was now so precious that not a drop should be wasted. (Read: I believe rainfall will be so scarce that we will need Wivenhoe to be full to cover the next 6, 7, 8.... years) There are some good scientists out there making quite good predictions; they are just not being listened to by the policy-makers.

Jan 17, 2011 at 2:35 AM | Unregistered CommenterAynsley Kellow

Aynsley,having read Franks essay on the matter,I agree it is a good,accessable work. It would indeed be interesting to see how water managers have integrated collective knowledge from the primary research,to syntheses like Franks'.

I reckon having gotten water consumption habits down over the years,any government would be loathe to let them go,given population projections...but it's an amusing scenario,imagining Anna Bligh urging Brisbanites to 'do their bit' and drink down the dam as the crisis intensified!

Jan 17, 2011 at 3:42 AM | Unregistered CommenterNick

Nick, I think there is a need for a parallel with Least Cost Utility Planning in electricity utilities: use of probabilistic approaches to planning and operation, and providing flexibility through pricing or even the notion of purchasing conservation. There's not much difference between a mixed hydro/thermal electricity system and a water supply system with desalination plant (or water recycling and groundwater, as in Perth). Strangely, after all these years, we have markets for electricity but seek to control water usage by regulatory fiat. There are even 'time-of-use' tariffs for electricity. Why should water not be priced according to its scarcity?

Jan 17, 2011 at 3:58 AM | Unregistered CommenterAynsley Kellow

I do think that Stewart Franks research and climate change projections has resulted in the Australian authorities deliberately confusing natural climate variability with man-made global warming in order to maintain a politically correct standpoint on environmental matters. This stance is representative of Trenberth's new null-hypothesis where all weather events are now deemed as being affected by global warming. Such thinking represents a real danger to Australians in that management of reservoirs has become an exercise in politics rather than a technical one in dealing with droughts and mitigating floods.

Australia's recent experiences in dealing with drought, fire and flood reveals that environmental political correctness is more likely to exacerbate the impact of extreme weather events on the local populace than mitigate them.

Jan 17, 2011 at 10:03 AM | Unregistered CommenterMac

From The Australian.

Quote, "More than 80 per cent of the flood in the Brisbane River at its peak last Thursday was the direct result of the release from Wivenhoe, the city's flood shield, of up to 30 per cent of its capacity, according to official data obtained by The Australian. The data shows that, without the unprecedented and massive release at a peak rate of 645,000 megalitres a day from the dam on Tuesday, January 11, the flooding in Brisbane would have been minimal."

This was a man-made disaster.

Jan 17, 2011 at 1:28 PM | Unregistered CommenterMac

Stewart Franks, Fire and flood under a tumultuous climate, 27/02/2009

Quote, "And yet at present Australia's historic variability does not figure in typical estimates of climate risk for planning purposes. Nor though should we pay much heed to those that may loosely call themselves climate change scientists and who make alarmist claims for the future climte. They should acknowledge that we never could predict the future climate of 10, 20, 50 or 100 years time, at least not with any credibility. It is no different now that we fear CO2.

If we cannot prevent climate-related disasters we can at least prepare for them. The recent tragedies of both fire and flood have lessons to teach. We should engage ourselves in developing more effective measures to reduce our vulnerability to the extreme vagaries of climate variability. More prescribed burns and more flood infrastructure would seem appropriate.

Whether we can predict climate on multiple timescales usefully or not, we should certainly be preparing ourselves for both ends of the spectrum of climate extremes at all times. I would argue that in a country as vulnerable as Australia, this should be happening irrespective of any consideration of possible impacts of increased CO2.

After all, if we fail to cope with natural climate variability what hope have we for coping with any supposedly catastrophic human-induced climate change?"

Jan 17, 2011 at 1:54 PM | Unregistered CommenterMac

Mac,no,I disagree. . I would not trust any of the news media to be adequately numerate or technically literate to cover this,especially on the run. They are stirring the pot.,because that's all they can do reliably.

A claim that 80% of the flood in Brisbane was a direct result of the release from Wivenhoe is superficial. It's a nonsense,because it implies that 0% of the flood need have come from Wivenhoe. It is possible with hindsight that some of that 80% could have been avoided,but in no way could all of it have been..this is provocative,agenda driven journalism. Finger pointing,before facts are established.

What does 80 % mean,anyway? 80% of the volume? 80% of the height?

"There is no doubt flooding occurred because of the release from the dam" say the 'experts',probably quoted out of context. Well yes,it DID contain dam water that was order to ensure the structural integrity of the dam in the face of rapid inflows and a threatening forecast. The flood also contained water from the other unregulated half of the catchment above Brisbane town,probably 5,000km2 in area.

The dam is not able to prevent all floods and was never designed to. At the scale of this one,it is designed to bring down the peak height. It is a mischief to imply that the dam would stop flooding,or minimise it to nearly nothing.

Not all material is available,but what is indeed says that the peak transient release from Wivenhoe at about midnight Tuesday 11/1 was 7465 cumecs. However,that is at the wall. When that hits the river at the bottom of the spillway,it slows down and stretches out,given the friction and irregularity of the river bed and such a peak is not transferred without change downstream to the city. It is not preserved.

Data from the first river gauge downstream,which included significant flood flows from an unregulated tributary,shows a peak transient flow of about 6900 cumecs soon after the peak release from the dam. Subtract at least 1000 cumecs from the tributary,and that translates to 5900 from the dam,a measure of how much the peak water has already slowed and flattened.

Of course this is still enough to cause flooding in Brisbane,but the peak drops lower and lower ,and the role of the tributaries is very significant.. the implication in the article is that 9,000 cumecs was the peak flow through Brisbane itself. This is absolutely untrue...absolutely and utterly misleading. The river at Brisbane is deeper and wider,the flow is slower the peak broader,and no transient,let alone sustained, flows of that volume were experienced.

The dam managers were working in real time ,not hindsight. The official forecast was for rain,heavy rain,to continue into the next day in the catchment. The dam was approaching critical heights and had to release a large amount. in the face of the forecast ,the choice was a sizeable flood,or risk overtopping and failure of the structure,certainly the uncontrolled triggering of the secondary spillway.

"..the direct result of the release of up to 30% of the dams capacity.." this is about right,but what does it really mean? The 24 hour volume at the height of release was probably 350 to 400GL,a third of the dams capacity. But more than that amount entered the dam at around the same time. At 190% plus full,there was not safe room for another 30%,hence the large release.

Don't take that article at face value. It is common knowledge,available in all published information about the dam, that Wivenhoe has its limits,like any dam.

Jan 17, 2011 at 2:32 PM | Unregistered CommenterNick


You maybe right about the trustworthyness of news media and the problems with current flood infrastructure in dealing with extremes of climate variability but the hand of man is evident to what happened to Brisbane.

I would like to no more about the pressures the managers of the dam were under. What were their priorities and how did they respond to the onset of La Nina conditions and the SE Queensland floods.

Jan 17, 2011 at 4:18 PM | Unregistered CommenterMac

If the dam had been at 60% a month or two ago, would that have helped? Is there a good reason to keep the dam at 100%?

This video , posted by Peter S above, tells me a lot about Brisbane City Council's mindset (look out for the guy at 4m36s who says that if water is mismanaged, it can cause disaster). Does the city council influence dam levels or not?

Jan 17, 2011 at 4:52 PM | Unregistered CommenterRob Fisher


SEQ dam release and flooding update - 06.01.11
Gate operations at Wivenhoe Dam will be required. To minimise downstream impacts, these releases will commence when flood levels in the lower Lockyer Creek subside.

SEQ dam release and flooding update - 07.01.11
Gate operations at Wivenhoe Dam will be required. To minimise downstream impacts, these releases will commence when flood levels in the lower Lockyer Creek subside. The rate of release will be similar to last week, at up to 130,000 megalitres per day.

SEQ dam release and flooding update - 08.01.11
At Wivenhoe Dam, all five gates are now open. Releases are expected to reach around 100,000 megalitres a day by this afternoon. Releases will be reviewed and may change depending on rainfall, inflows into the dam and river flows.

SEQ dam release and flooding update - 09.01.11
At Wivenhoe Dam, releases commenced during the evening of Thursday 6 January 2011, with all five gates opened by Saturday 8 January 2011. Releases have reached around 116,000 megalitres a day. Gate operations will continue to be reviewed and may change at short notice depending on rainfall, inflows into the dam and river flows.

SEQ dam release and flooding update - 10.01.11 - AM
Significant rainfall across the catchment has lifted Wivenhoe Dam's level to above 140 per cent and Somerset Dam to above 150 per cent.
Although releases are being made, large quantities of water continue to flow into the dams and are being held back in order to manage impacts downstream and allow for other inflows from urban runoff, and the Lockyer and Bremer Rivers to subside.
Overnight, Fernvale and Mt Crosby Weir Bridges together with a number of local roads became inundated. They joined the others already impacted, including Twin Bridges, Savages Crossing, Burtons Bridge, Kholo Bridge and Colleges Crossing.
In order to relieve the quickly filling flood storage compartment, and with more rain forecast, controlled releases from the dam have been increased today from 116,000 megalitres per day to 170,000 megalitres per day. These releases are a necessity.

SEQ dam release and flooding update - 10.01.11 - PM
Significant rainfall in the catchments has lifted Wivenhoe Dam's level to 154 per cent and Somerset Dam to 158 per cent, despite continuing releases.
Although releases are being made, large quantities of water continue to flow into the dams. Water is being held back in order to manage impacts downstream and allow for other inflows from urban runoff, the Lockyer and Bremer Rivers to subside.
Overnight, Fernvale and Mt Crosby Weir Bridges together with a number of local roads became inundated. They joined the others already impacted, including Twin Bridges, Savages Crossing, Burtons Bridge, Kholo Bridge and Colleges Crossing.
In order to relieve the quickly filling flood storage compartment, and with more rain forecast, controlled releases from the dam have been increased today from 116,000 megalitres per day to 172,000 megalitres per day. Further increases to the release rate are planned, to approximately 240,000 megalitres per day by midnight.
These releases are a necessity as, at the peak, Wivenhoe Dam was receiving more than twice the volume of Sydney Harbour each day.

SEQ dam release and flooding update - 11.01.11 - AM
NOTE: All SEQ dams are safe, stable and operating within their design specifications.
Significant rainfall received across catchments has caused waterways upstream of Somerset and Wivenhoe Dams to rise quickly overnight.
Wivenhoe Dam is currently at 173% and rising. Somerset Dam is at 160%.
Controlled releases through the five gates have been held at around 236,000 megalitres since early last night but will need to be increased further today.

SEQ dam release and flooding update - 11.01.11 - PM
NOTE: All SEQ dams are safe, stable and operating within their design specifications.
Wivenhoe Dam is currently at 190 per cent and rising. Somerset Dam is at 176 per cent and also rising.
Controlled releases through Wivenhoe’s five radial gates have now been increased to around 490,000 megalitres per day. This is expected to increase. Releases are being made in consultation with the Bureau of Meteorology and local councils and an effort to limit downstream impacts where possible. Note these large releases are necessary for the safe management of the dam.

SEQ dam release and flooding update - 12.01.11 - AM
NOTE: All SEQ dams are safe, stable and operating within their design specifications.
Currently, Wivenhoe Dam is at 190 per cent down from 191 per cent overnight.
This reflects the current ease in the weather. Somerset Dam is now at 190 per cent.
Wivenhoe’s five radial gates are currently releasing 205,000 megalitres per day, down from 370,000 megalitres and an overnight peak of 645,000 megalitres.
This strategy is to allow for the Bremer and Lockyer Rivers to subside.
After the expected downstream peak in the lower Brisbane River has passed, releases will need to be increased to 301,000 megalitres per day.
However, this increase is unlikely to cause a second significant rise in the river.

SEQ dam release and flooding update - 12.01.11 - PM
NOTE: All SEQ dams remain safe, stable and operating within their design specifications.
Currently, Wivenhoe Dam is at 189 per cent, down from 191 per cent overnight. This reflects the current ease in the weather. Somerset Dam is now at 186 per cent, discharging 123,000 megalitres per day into Wivenhoe Dam via a sluice gate.
Wivenhoe’s five radial gates continue to release 215,000 megalitres per day. This is considerably down from an overnight peak of 645,000 megalitres and will remain at this level to allow for the Bremer and Lockyer Rivers to subside.
After the expected downstream peak in the lower Brisbane River has passed, releases will be increased to 301,000 megalitres per day, however, this increase is unlikely to cause a second significant rise in the river.
These controlled releases must continue in order to relieve Wivenhoe Dam’s swollen flood storage compartment in order to create space for further rainfall and inflows, should they occur.

SEQ dam release and flooding update - 13.01.11 - AM
NOTE: All SEQ dams remain safe, stable and operating within their design specifications.
Wivenhoe Dam is at 187 per cent, and is dropping gradually with controlled releases through all five gates of 215,000 megalitres per day. This is down from the peak of 645,000 megalitres earlier in the week.
The dam’s slow recession is due in part to inflows of 121,000 megalitres per day via a sluice gate from Somerset Dam. Somerset is at 174 per cent.
After the expected downstream peak in the lower Brisbane River has passed, releases will be increased to 301,000 megalitres per day.
This increase is unlikely to cause a second significant rise in the river and is necessary in order to relieve Wivenhoe Dam’s swollen flood storage compartment in order to create space for further rainfall and inflows, should they occur.

SEQ dam release and flooding update - 13.01.11 - PM
NOTE: All SEQ dams remain safe, stable and operating within their design specifications.
Wivenhoe Dam is at 186 per cent, and is dropping gradually with controlled releases through all five gates of 228,000 megalitres per day. This is down from the peak of 645,000 megalitres earlier in the week.
The dam’s slow recession is due in part to inflows of 120,000 megalitres per day via a sluice gate from Somerset Dam. Somerset is at 167 per cent.

Full details at the website mentioned.
It takes 36 hours for release at the dam to affect the level at Brisbane City Gauge which peaked on 13th Thursday.

Hell of a coincidence!

Over the night of the 11th release rate increased by a multiple of 3 in a successfull atempt to lower the level from 190%.
Could this intense 12 hour period have been avoided if the dam had a further 40% capacity to begin with and release rates were used to maintain the downstream levels but tuned toward the 100% level rather than the 200% level?

Jan 17, 2011 at 5:25 PM | Unregistered CommenterLord Beaverbrook

I think a very interesting question is: Did Brisbane Council decide to hoard water and quietly drain off any excess as waste, RATHER than relax the rules it set during the drought years so that citizens could more freely and cheaply use the resource for their benefit - a move which would have required the council to relinquish punitive political and financial powers it gained over its citizens on the back of the drought.

It strikes me that the council could only sustain its heavy-handed and profitable power by sustaining the Green message of water as a 'precious' resource... even if that message was clearly misleading and outdated to any sensible person. Part of the reason for the alleged mismanagement of the Wivenhoe dam (and the disaster it led to) could be the council's own greed and ideology-driven denial.

Jan 17, 2011 at 5:54 PM | Unregistered CommenterPeter S

"decades of evidence that droughts are succeeded by floods"

And, as noted by Goscinni and Uderzo in 'Asterix and the Soothsayer', the sun usually comes out after a rainstorm, thus convincing the gullible villagers that the soothsayer had prophetic powers, which turned out to be completely illusory. Plus ça change...

Jan 17, 2011 at 6:39 PM | Unregistered CommenterJames P

And the message continues:

Water Grid Update - 14.01.11

MEDIA RELEASE - 14 JANUARY 2011: Issued at 4:00pm

Despite significant operational challenges caused by flooding, the major water supplies remain reliable in the Water Grid supplying Brisbane, Ipswich and the Gold Coast.

Deputy Premier Paul Lucas said that the region’s major water treatment plant at Mount Crosby had been partly flooded and impacted by poor water quality in the Brisbane River.

“While production is increasing, some of our water treatment infrastructure was impacted by floods and the output is still being affected by turbidity in the Brisbane and North Pine Rivers.

“One of Mount Crosby’s two water treatment plants, East Bank, was flooded resulting in substantial mechanical damage to large pumps moved by the force of the water.

“Both Mt Crosby plants are now back on line and gradually being brought up to maximum production.

“We are also using the desalination plant and transfers across the Water Grid to resupply local water reservoirs where water levels declined while Mount Crosby was off line.”

Mr Lucas urged residents and businesses in Brisbane, Logan and Ipswich who had not been affected by floods to use only what they need for the next few days.

“Our key priority in these areas is maintaining sufficient water for those households and businesses who need to use more in the immediate flood recovery.

“Flood affected residents and businesses will need to use a lot more water than normal, so its important that people who haven’t been affected try to use water wisely,” he said.

“In suburbs not directly, affected like Wynnum and Manly, we don’t need to use a lot of water, so I’d ask every one to do their part in the Queenslander tradition.”

Water Grid Manager CEO Barry Dennien said that people who haven’t been affected by the flood can help by using the same cautious water use practices that saw us through the drought. These include:

• take only short 4 minute showers
• don’t water gardens
• don’t hose buildings, driveways and footpaths
• delay washing your cars
• don’t fill pools
• only use dishwashers when you have a full load
• turn-off taps when you don’t need water

“During the drought South East Queenslanders showed how well we could conserve water. This latest crisis means residents and businesses outside the directly flooded affected areas need to do the same again” Mr Dennien said.

“I can assure everyone who has not been directly impacted by flooding that by conserving valuable water over the next few days you will make a real and important contribution to the flood recovery effort” said Mr Dennien.

Jan 17, 2011 at 6:53 PM | Unregistered CommenterLord Beaverbrook

And to make sure that the message gets across.

A report on the flood disaster and climate change will be undertaken by an expert on the federal government's multi-party committee which is investigating ways to price carbon.

Professor Will Steffen, a member of the climate change committee set up by the Gillard government in September last year, told AAP he was working on a report covering the floods.

Jan 17, 2011 at 7:20 PM | Unregistered CommenterLord Beaverbrook

Lord Beaverbrook,
Steffen is one of those 'climate scientists' whose qualifications in other disciplines never limit their expertise as long as they are on message:

'He began his career as a chemical engineer with a BSc from the University of Missouri. He holds an MSc (1972) and PhD (1975) degrees in chemistry from the University of Florida. Following a research fellowship at the Research School of Chemistry at ANU from 1977-1980, Will joined the CSIRO Division of Environmental Mechanics in the roles of science management, editing and communication.
In 1990 Will took up the position of Executive Officer for the Global Change and Terrestrial Ecosystems project of the International Geosphere-Biosphere Programme (IGBP). From 1998 to 2004 he served as Executive Director of IGBP and was based in Stockholm. Will returned to Canberra in mid-2004 and took up a Visiting Fellowship with the Bureau of Rural Sciences, Department of Agriculture, Fisheries and Forestry, Australian Government. A year later he joined the ANU and was the foundation director of the Fenner School of Environment and Society before moving to his current position with the Climate Change Institute.'

A chemists would be ideally qualified to report on flooding, compared with, say, a hydrologist like Stewart Franks. Me thinks Professor Steffen is 'sound', Sir Humphrey!

PeterS: To my knowledge, SEQ Water is a state government entity, serving several local government areas in the region. Brisbane City Council is the largest local government in Australia - most other cities lack a single council - but it does not control SEQ Water.

Jan 17, 2011 at 8:36 PM | Unregistered CommenterAynsley Kellow


The corporation, owned by the State Government (20 per cent), Brisbane City Council (45 per cent and 11 other southeast Queensland local authorities (35 per cent),

Jan 17, 2011 at 9:37 PM | Unregistered CommenterLord Beaverbrook

Thank you for the detail, Your Lordship!

The BCC doesn't have a controlling share, but is the only LGA that might suffer the consequences of flood damage, while all would benefit from holding water for supply. That suggests at least an unhelpful asymmetry in the controlling shareholders.

One thing that I think will be interesting is whether the standard operating rules for Wivenhoe were changed after the commissioning of the water network and the desalination plant. The value of water held in WIvenhoe should have had a much different value when compared with the value of empty storage for flood mitigation after that moment. In the same way, the operation of the Tasmanian Hydro-electric system changed once it was interconnected with the National grid (and market) and some long-term storage stations had more value as peak generators, relying on the Victorian, NSW and QLD coal-fired generators for long-term security in drought (with some help from Bell Bay, converted from oil to cheaper gas). The operating rules should have changed once there was greater water supply security.

Jan 18, 2011 at 12:06 AM | Unregistered CommenterAynsley Kellow

Aynsley, I agree.

There is a point here that needs to be raised now by the people of Brisbane and the reason that I stipulate now is the fact that there is a strong possibility that it is going to happen again.

The severity of the situation is that Brisbane came within an hour or two of complete devastation. If the Wivenhoe dam had breached there would of been huge loss of life and property and I applaud the dam operators for containing that situation.
From a risk management angle the operators should never have had to face the decision to partially flood the city in order to save the dam.

There is going to be more cyclonic rain in the next month or two, this is expected and forecast. The lesson of January has to be learnt and learnt fast so that policy changes to ensure that a repeat of the situation doesn't happen in the coming months.

There has been news reports of an investigation already started, the time scale of which is unknown but currently the policy remains the same.

SEQ dam release and flooding update - 18.01.11
Wivenhoe Dam is at 107 per cent and continues to drop steadily. Releases remained constant overnight at around 176,000 megalitres per day and are now reducing with the commencement of the gate closing sequence which began at 9am this morning.
The five radial gates are expected to be shut by Thursday to allow for the high tides that have been predicted for later this week.
Subject to weather, it is expected that the dam’s flood storage compartment will have been returned to near zero from Thursday with any smaller excesses discharged via a smaller cone valve.
Inflows and water levels continue to be monitored in the Brisbane and Pine catchments.
Somerset Dam is at 99 per cent with small discharges through the cone valves into Wivenhoe.
All sluice gates at Somerset are closed.
Releases are being made in consultation with the Bureau of Meteorology and local councils and every effort is being made to limit downstream impacts where possible.

All the dams are returning to the 100% water usage level to which they will be maintained with I would guess the local water restrictions still in place. Lets 'hope' that some internal decisions have been made at SEQWater that doesn't allow the dam to reach the same capacity and the operators to have the same choice forced upon them.

Jan 18, 2011 at 8:44 AM | Unregistered CommenterLord Beaverbrook

Your Lordship,
Agreed. Why keep those storages that provide flood protection at 100% in the face of what we know is a strong La Nina? Apparently the desal plant has been recomissioned, and is feeding water in to the network, because there are problems with water treatment facilities. They are right to manage releases so as to respond to tidal peaks, but beyond that is each ML that has to be produced by the desal plant produced at a higher marginal cost than the protection of Brisbane - if there are not continuing rains to recharge the reservoir later in the year? My suspicion would be that it is not. I'd certainly rather run the risk of paying the marginal cost of desal to provide enhanced flood protection. As you point out, it is early in the cyclone season, and this was apparently just the rain from the tail of a Cat 1 Cyclone (Tasha). There might be more to come. Let's trust the LR forecasters and Stewart Franks of this world. We could call it the Precautionary Principle!

Jan 18, 2011 at 9:04 AM | Unregistered CommenterAynsley Kellow

LB - "floods-report-to-go-to-carbon-price-committee"

That's how they used to do things in the old Soviet Union. Every person, every policy, every report, every proposed action was judged politically by a committee of communist party activists before they or it were approved.

Jan 18, 2011 at 11:45 AM | Unregistered CommenterMac

A new claim - "Wivenhoe Dam eased the Brisbane flood"

Quote, "Mr Dennien (SEQ Water Grid spokesman), who has been under pressure over how dam releases were handled, believed that water was released according to a prescribed manual laid down by the State Government.

"The whole idea is that we have a very strict set of rules about how we handle these events, and we didn't stray from the manual," Mr Dennien said. "The more we look at the rainfall event and how water was released, the more confident we are in how we handled things."

The dam had never held such large amounts of water, since being built in 1984, and had never operated under such extremes.

After every flood event, operating instructions were reviewed.

He said staff monitored the dam 24 hours a day, right until the weekend leading up to the floods via 200 gauges.

As to whether the Brisbane flood could have been avoided by releasing more water on the weekend leading up to the floods, Mr Dennien said the dam was operated as per instructions.

"We went into Monday holding what the dam manual told us to hold," Mr Dennien said.

He said 50 per cent of the catchment was downstream of the Wivenhoe Wall, an area over which dam managers had no control."

It would be interesting to read that prescribed manual.

Jan 18, 2011 at 1:29 PM | Unregistered CommenterMac

Further reading: from this we have:

Typical emergency or potential problem identification includes but is not limited to:

Overtopping imminent... Storage full and water level rising... During periods of excessive rainfall

Which should lead to:

Emergency Event Report
Following an emergency, an Emergency Event Report should be completed which contains:
• a description of the event
• instrumentation readings (where appropriate)
• description of any observed damage
• photographs
• the EAP
• details of communication which took place during the emergency
• comment on the adequacy of the EAP
• any recommendations or suggested changes to the EAP.
Dam owners have the responsibility for implementing the recommendations contained in the
Emergency Event Report. Comprehensive inspections and ultimately audits undertaken by the
Regulator, will evaluate the dam owners response to Emergency Event Reports.

Anyone for FOI request?

Jan 18, 2011 at 3:56 PM | Unregistered CommenterLord Beaverbrook

Note that it is to be assumed that the dam reservoir is initially at Full Supply Level at the
start of the flood event.

The required Acceptable Flood Capacity (AFC) is the discharge capacity required to pass the
critical duration storm event without causing failure of the dam.
Note: The owner of the dam should be aware that the fall-back method may result in a higher design requirement and consequent higher cost of the upgrade required to bring it up to the required standard than the alternative risk assessment procedure (incorporating ALARP).

Wikipedia: Wivenhoe Dam

During a flood the dam is designed to hold back 1.45 million megalitres (1.18 million acre feet) of additional water for flood mitigation or 225% capacity.[3] Under the water release plan which is defined by law, excess water must be released from the dam within seven days of it reaching 100% capacity.[4] Between April 2004 and September 2008, a 165-metre (541 ft) wide auxiliary spillway with a three-bay fuse plug was installed on the western portion of the dam to further mitigate flooding.[5] In 2007, a feasibility study concluded that Wivenhoe Dam failed to satisfy the Australian National Committee on Large Dams (ANCOLD) guidelines on acceptable flood capacity.[6]

'The development came as the dam's operator, South East Queensland Water Corporation, declined to comment on what action it had taken in response to a 2007 report that noted the giant dam did not satisfy Australian National Committee on Large Dams (ANCOLD) guidelines on acceptable flood capacity.'

The AFC seems to have been tested adequately this year.

Jan 18, 2011 at 4:59 PM | Unregistered CommenterLord Beaverbrook

As I suspected, the operators appear to have followed their manual, and are indicating they don't set the rules. There is another op ed this morning, from a water economist, echoing my point about the need to change those rule sin the balance between water supply and flood mitigation after the desal and netwark were commissioned (and in the face of La Nina forecasts):

Jan 18, 2011 at 8:56 PM | Unregistered CommenterAynsley Kellow

Has anyone worked out if the dam was actually manned over the weekend of 8-9 Jan? I mean operated by those with authority to make decisions (in accordance with the Operating Manual).

It sounds like Mr Dennien (SEQ Water Grid spokesman) is making statements (as quoted by Mac above) which are very carefully tailored to skirt around the issue of weekend manning. His oddly worded statement that "staff monitored the dam 24 hours a day, right until the weekend leading up to the floods via 200 gauges", suggests that staff were working 24 hours a day up until the weekend (7 Jan), rather than up until the actual imminent flooding event (10 and 11 Jan).

Could it be that senior staff at the dam packed up and went home for the weekend - as usual - on the Friday evening (7 Jan), leaving the dam unmanned or (more likely) with a regular skeleton staff of those without any authority (or expertise) to take crucial decisions about run-offs of 'precious' water... especially so if those decisions appeared to be at variance to procedures laid down in their 'Operator's Manual'?

If so, this would leave us with a 'lost weekend' - where the dam's levels could have been safely adjusted downwards - freeing up more capacity - but weren't.

Jan 18, 2011 at 9:55 PM | Unregistered CommenterPeter S

Nick, you had plenty to say 12 months ago, and wanted proof !

What say you now ??

Go read here and then get back to us.

"Dam bursts on new evidence as Queensland flood inquiry is recalled "

"THE Queensland floods inquiry has been recalled to hear extraordinary new evidence that suggests the wrong strategy was used to manage Wivenhoe Dam days before Brisbane was inundated, throwing Premier Anna Bligh's timetable for the state election into disarray. "

Jan 24, 2012 at 9:41 PM | Unregistered CommenterChris in Hervey Bay

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