Most people had the impression that the four flood engineers, Robert Ayre, John Ruffini, John Tibaldi and Terry Malone, had done pretty well during the Brisbane 2011 flood event, which began on 6 January when the Wivenhoe Dam first exceeded full storage capacity of 67m bringing the flood compartment into play. The gates were finally closed ending the event on 19 January. Later some argued that on the Saturday and Sunday 8-9 Jan there could have been more aggressive releases, flooding the remaining rural bridges below the dam at Fernvale and Mt Crosby Weir, thus lessening the later Brisbane flood peak. Against that, it was argued that the weather forecasts didn’t justify such action, that the effect would have been minimal and that some low level flooding may have resulted from that act alone. What’s more, the forecast rain may not have eventuated.
In February the Queensland Floods Commission of Inquiry reconvened as a result of reporting in The Australian by Hedley Thomas which suggested there had been a major breach of the flood manual for the operation of the Wivenhoe and Somerset Dams (7th revision) and that there had been a cover-up to disguise the fact. The Commission’s Interim Report of August 2011 had been thorough and sympathetic. The Commission noted such things as non-compliance in relation to weather forecasts (the forecasts were so erratic the engineers ignored them in determining gate settings, contra the manual). They also noted deficiencies in recording decisions and actions in real time. They made a host of recommendations about improvements (see Recommendations relating to Chapter 2) but the impression was of a job well done. Chapter 2 (Section 2.7) remains perhaps the best blow by blow account of how the flood was managed.
Chapter 16 of the Final Report does in fact find that the manual was breached from 8am on Saturday 8 Jan for about 36 hours until the evening of Sunday 9 January. It found that the engineers were operating in strategy W1 rather than W3 as claimed in the Flood Event Report of 2 March 2011 (downloads at bottom of screen). It also found that three of the engineers knowingly misled the Government and the Commission about the “W” strategies. It recommended that Ayre, Tibaldi and Malone be investigated by the Crime and Misconduct Commission in relation to the brief to the Minister of 17 January 2011, the Flood Event Report of 2 March and other documents, as well as in testimony to the Commission to see whether offences had been committed against the Criminal Code and the Crime and Misconduct Act, 2001.
Serious stuff. Hedley Thomas in these articles was well-satisfied with his work. He spoke of “mismanagement”, a lack of competence and assumed that compensation was clearly due to flood victims who had had their homes and properties needlessly damaged. Here Thomas, presumably with presumed hydrological expertise not available to the Commission, has gone beyond what they said. They had asked an independent hydrologist, Mr Mark Babister, to review the flood documentation and reporting and to undertake modelling of alternative strategies. Babister’s report had become available just as the Interim Report was to be printed. His finding could not be incorporated in the document, but a statement was inserted saying that nothing in his findings conflicted with the Commission’s interim report. He found that:
the flood engineers managed Wivenhoe Dam so that its flood mitigation effect was ‘very close’ to the maximum achievable within the constraints of the manual.
Furthermore, he said that an aggressive early release would have been “highly risky” and would have used the Wivenhoe as a flood amplification dam rather than a flood mitigation dam. That’s all from the Final Report. The Commission did not back off Babister’s findings as alleged by Thomas. What they did say was:
Ascertaining the practical result of acting more quickly also is subject to the uncertainties inherent in the modelling; but again, the possibility exists of at least some improvement in the flooding outcome for Brisbane and Ipswich.
The possibility of “at least some improvement”. And if the class action lawyers want to know exactly which homes and buildings would have been saved they will have to do their own hydrological modelling. The models Babister used were not sophisticated enough to show this, and in any case his technical modelling has not been made available.
The problem, you see, was that the engineers thought and acted in relation to the information they got from rain gauges, dam input and output flows, dam levels and conditions outside the catchment areas, modelled to forecast a stream flow at Moggill 16 hours after dam releases.
What they were meant to do was to pause there, check which “W” strategy they were in, and then make decisions. What they did was to go directly to making decisions. The “W” strategies were filled in later as part of the reporting. In doing so they followed the same methodology that had always been employed from back in the 1990s.
The Commission took the view that the engineers would make better decisions if they operated a different way, that the “W” strategies be consciously chosen and be front of mind at all times. What’s more, compliance with the manual demanded it, they said.
I’ll come back to these issues in a second post. In this one I’d like to give an account of the actual event, which was a good deal more threatening than most realise.
The Wivenhoe Dam in context
The Wivehoe Dam catchment drains some 7,000 square kilometres of the Upper Brisbane River. It includes the Stanley River, a tributary flowing in from the north which is dammed by the smaller Somerset Dam. The Locker Creek draining some 3,000 square kilometres joins from the west just below the Wivenhoe and just above Lowood. The Bremer River draining some 2,000 square kilometres flows through Ipswich and joins just above Moggill. It takes about 16 hours for water to flow from the Wivenhoe to Moggill.
A flow of 4,000 cubic metres per second (cumecs) at Moggill is taken in the manual as a marker for urban inundation downstream in Brisbane.
You can get an overview of the geography from the two maps in this post. The total average rain during the flood event is given in this map:
Figure 1: Flood rain
Three points to note. First, the Pine River is an entirely separate system, not a tributary of the Brisbane River. Second, there is a slab of country in the segment designated “Lower Brisbane” which would also drain into the river above Moggill. Finally, the cloudburst that flooded Toowoomba and devastated Grantham and the Lockyer Valley doesn’t show up in the overall. That might be because there was no rain gauge on the eastern escarpment of the Toowoomba range. The other catchment numbers might also be underdone as the engineers found that there was more water coming at them than was implied by the modelling based on the gauges.
A monster flood
In the 2011 event 2,650 gigalitres of water flowed into the Wivenhoe dam. The comparable figures for 1893 and 1974 would have been 2,740 and 1,410 respectively. In February 1999 there was an event with 1,220 GL that most people don’t remember, because the Wivenhoe had been built and coped with it. Sydney Harbour holds about 500 GL. Here is a graph showing historical flood levels:
Figure 2: Brisbane floods
That’s at the Port Office in the city reach. The 2011 flood was 4.6 metres, but the Flood Event Report tells us that it would have been two metres higher without the Wivenhoe. Later modelling by Sinclair Knight Mertz suggested about 1.2m higher.
In fact we had a flood in two parts, 30 hours apart. The dams would have coped pretty well with the first, but were overwhelmed by the second. The pattern is shown in this image from the report:
Figure 3: Wivenhoe Dam flood profile
The Executive Summary of the Flood Event Report (well worth a read) tells us that the maximum flow rate of the first peak has been estimated to be 200% of the 1974 event and the second 230%.
The story, in brief
The flood operations centre was established, as is required, on 6 January when the Wivenhoe Dam reached the full storage level of 67 metres. Malone and Tibaldi were engineers from Seqwater, which owns and manages the dam. Ayre was a senior engineer from Sunwater, which was contracted by Seqwater to operate the centre. Ruffini was a senior engineer from DERM. They were supported by 13 flood officers at various times. My impression is that the flood operations centre was in the Brisbane CBD.
Strategy W1 was then automatically in operation on 6 January, where the focus is on the impacts on rural life below the dam, principally the river crossings. By Friday night the five lower crossings were inundated, leaving the Fernvale Bridge just below Lowood, which goes under with 2,000 cumecs, and the Mt Crosby Weir Bridge down near Moggill just above where the Bremer joins, which goes under with 1,900 cumecs. The dam level was predicted to rise above 68.5m, which triggers either W2 or W3. At 5am on Saturday morning Ruffini issued a gate opening schedule to cope with this situation, based on modelling done by Malone the previous day. At 8am on Saturday when the 68.5m trigger point was breached there was about 171 GL in the flood compartment, with inflows at 1,500 to 1,800 cumecs. Outflows were already above 900 cumecs and were increased to about 1,200 cumecs during the day.
Under both W2 and W3 priority must be given to preventing urban inundation, with 4,000 cumecs at Moggill the marker. Consideration is also given to lower level objectives, principally keeping the two higher bridges open. It should be noted that at 8am natural flows at Moggill, that is flows other than those from the dam release, were at 770 cumecs. At least two engineers (Ayre and Tibaldi) knew that water troubles in Brisbane start way lower than 4,000 cumecs at Moggill, in fact around 2,000 cumecs.
The increased releases saw the dam rise to 68.65m at 11pm then begin to fall again. Five of the six situation reports issued on Saturday and Sunday mention the predicted impact in millimetres at the Port Office in the Brisbane CBD. The exception was Sunday morning, which mentioned the dam level falling.
Overnight rain on Saturday night caused concern. It was decided to have a meeting of all four engineers on Sunday afternoon, with three present and Tibaldi on the phone. Malone compiled a scenario in preparation. Both this document and the meeting notes mention the rain influence tending to miss the upper Brisbane segment and move south to the Lockyer and Bremer catchments according to the forecast. They decided to keep releases to about 1,400 cumecs with the possibility of holding back more water to allow the Bremer and Lockyer water to pass.
Although there was considerable rain to the south the weather system did in fact settle over the Upper Brisbane and especially the Stanley catchment and Mt Glorious. An outflow level of 1400 cumecs decided at 3.30pm was passed at 6pm and increased steadily from there.
The first peak inflow of 10,095 cumecs was reached at 8am on Monday 10.
The cloudburst near Toowoomba which devastated Grantham occurred from about 2pm on Monday. The engineers didn’t know about it for about three hours as it fell between the gauges on the eastern escarpment of the range and didn’t show on radar. It takes about 24 hours for the water to get to the Brisbane River so they had plenty of notice. At 8pm the engineers were advised that the rain in the Upper Lockyer was estimated at 600mm.
Monday was a wild day. It began with a phone call at 12.45am from the Brisbane City Council advising that according to their maps inundation would occur with 3,500 cumecs at Moggill, not 4,000. There was a second phone call from the BCC at 9.40am. I think it was during this one that the engineers were told that a flow of 3,500 cumecs at Moggill would fully submerge 322 properties and impact 7,000. The engineers agreed to try to hold it to 3,500, but had to abandon this by 3pm. By that time the situation had deteriorated to the point were they had to warn of possible Brisbane flooding and the dam was forecast to rise to 75.2m with rainfall forecasts included. Then they heard about the Toowoomba/Lockyer downpour.
And then as the clock went past midnight the fun really began.
The inflows fell until 2am on Tuesday when they reached 3,594, but the rain had increased. In the early hours of Tuesday morning it became apparent to the engineers that the water coming at them in the Wivenhoe catchment was more than the models indicated, based on the gauge readings. Estimates indicated falls of up to 700mm.
Inflows rose again to reach a new peak of 11,561 at 1pm. Meanwhile the dam level had reached 74m at 11am.
When the dam level is predicted to go above 74m the main focus must be on preserving the dam wall, because 244,000 people are said to be at risk. The first of three fuse plugs in the auxiliary spillway automatically opens at 75.7 metres, the third at 76.7. The wall is 80m.
When the inflows peaked at 1pm the dam was at 74.39m and forecast to go to 76.2. The Moggill flow was approaching 5000 cumecs and rising fast. The sluice gates at Somerset were closed to hold back a bit more there. Permission was gained to let the level at Wivenhoe float above 74m for a time. But even though the inflow was tapering the outflow had to be increased to a level above the inflows. This occurred at 7pm when inflows were 6,876 and outflows were 7,464. The dam peaked at 74.97 and tapered from there.
At 74m the dam was approaching 180% of normal storage capacity. At its peak it was 191% of capacity. The nominal peak flood is 225%, but the intent is to bring it back to under 74m as soon as possible without blowing the fuse plugs with releases as necessary, albeit with consideration of downstream damage.
The dam was above 74m from 11am on Tuesday until 6am on Friday.
The requirement is to drain down the lake to full storage capacity within seven days, which is why the outflows were held steady at about 3,500 cumecs during that process.
Moggill peaked at 12,095 cumecs at 11am on Wednesday 12 January. At the Port Office in the Brisbane CBD the flood peaked at 3.00am on Thursday 13. At that time the flood height was 4.6m and the flow 9,500 cumecs according to the Flood Event Report. During the week tides were up to half a metre lower than the previous and following weeks.
From this article:
An estimated 14,100 Brisbane properties were affected, while in Ipswich about 3000 homes were flood damaged. In Brisbane, the number of residential properties inundated totalled 1203.
The engineers decided to double team from Sunday night, with each doing a 12 hour shift every 24 hours. Later as they dealt with the dam level peak I understand all four were there at times, conducting reviews at 30 minute intervals.
As the floods rose in Brisbane three were cut off from home and slept in a meeting room. I’ve not heard how the flood officers who supported the engineers got on.
Weather forecasts
Precision in weather forecasting at these times is not really adequate to dealing with floods. For the first few days from 6 January actual rain was considerably less than the forecasts. On Sunday morning a 24-hour forecast of 50mm was issued for the catchment, whereas 149mm actually fell. On Tuesday at 4pm when decisions were being made to increase the outflows to above the inflows the forecast was for 75mm in the next 24 hours. In fact the system weakened and only 12mm arrived. Thankfully. And thankfully the engineers held their nerve and didn’t up the release in anticipation.
What difference would a 75% dam level make?
Dicsussion on this matter started immediately after the flood. I did a post on 21 January. My guestimate of the difference it would make was about 28cm (see this comment).
Turns out Babister’s modelling came up with 30cm (see Final Report Section 16.14.3, or p525, Scenario 3). But if the manual strategy trigger points were ratcheted down by 25%, the gain would be 60cm at the Port Office and 1.3m off the 17.6m level reached at Moggill. That’s perhaps worth doing, but I still worry, as did John D in the post, that in a drought you would leave yourself short of time to construct additional desalination plants.
Also it seems to me insane to wind down the dam in September if an El Nino is predicted. It is also insane to be letting water out at the end of March, as happened last week, to bring the dam below 75% at the end of the wet season when the La Nina has broken up.
If the Wivenhoe dam engineers are shown to have mismanaged their management that opens up the possibility for insurance companies to sue the government (ie the taxpayers).
This would allow the monied class to leverage the tax raising ability of governments to its own profit. An outcome that naturally the Australian would be very happy about.
Impressive report Brian obviously involving a tremendous amount of work. What a pity Hedley Thomas didn’t do as much.
Good one Brian. Shame that most (all?) MSM failed to meet this standard. The message coming across from the MSM was that the manual was god, the engineers devious incompetents and that the CEO should have abandoned his holidays sooner than he did and take personal charge.
My take on what you said is that the engineers did a good job on the basis of the information that they had at the time and their actions would have saved 300 houses from damage if the weather had been as expected when the decisions to delay increasing flows above 3500 were made. I must admit that experience as a commissioning engineer, operating manager and control room operator as well as working 12 hr plus shifts give me a feel for the sort of pressure the engineers would have been under. It also creates a wee bit of prejudice against lawyers and journo’s who have never been it the sort of situation.
There are a number of dangers that arise from some of the things that have been said:
Firstly, it would be very dangerous we have a legal situation that says the dam operators can only be sued if the manual is not followed. It is not practical to have a manual that covers all eventualities. This is why there were engineers on shift who had the technical competence to make decisions. It is crucial that that the engineers are able to make decisions without having to consider legal ramifications.
Secondly, we are currently obsessed by the flood issue and seem to have forgotten how close Brisbane came to essentially running out of water a few years ago. If this had happened the economic damage would have made the flood costs look like petty cash. As you say,
This decision needs to be publicly challenged.
Excellent post, Brian. Your first section shows the problem with legally-focussed commission investigations. They aren’t framed properly to address risk and they don’t understand risk. The Victorian Bushfire Commission is another example.
My view is that these commissions be based on how risk was managed, have the skills to forensically examine risk and risk management, then assess whether the regulations and actions of individuals were adequate. Only then should responsibility be allocated. Responsibility should be assessed at personal, institutional and governance levels. The trouble with rules in these situations is they often don’t work in emergencies (for many reasons). So assessing actions against regulations is a key task.
Then, it can be tested in court. Blame and allocation of penalty and recompense get dealt with by courts.
The outcome of this event will be a further retreat from expertise and knowledge as in other professions. Prepare for your next flood to be managed by politics, vox pop & prayer. Perhaps talk back callers to radio stations could directly control the sluice gates. And a “War on weather” could be declared!
I’ll put up a post tomorrow that examines why the Commission decided to refer three engineers to the CMC. But to foreshadow, I think there was a problem with how the engineers communicated what they’d done and how they explained it to the Commission in hearings last year. But there is also a problem with the manual itself.
I’m not sure how the whole insurance thing sits, but there is no legal requirement for the engineers to follow the manual. It’s just that they are legally exempt if they do. Seqwater, the dam owner and operator, is said to have insurance that covers anything they might do. The issue is complicated, because Seqwater contracted Sunwater to operate the flood operations centre. Ayre was from Sunwater and presumably nominally in charge. Ruffini was from DERM and Malone and Tibaldi were Seqwater employees.
If a private insurance company is going to be hit they would have a fiduciary duty to defend any claims.
This brings into play the standard of proof. The Commission was using the balance of probabilities, plus the non-existence of another reasonable explanation. If charged, the engineers would have to be shown to be guilty beyond reasonable doubt. As far as that affects the mitigation outcomes, and yields a quantum of damages, I suspect that would be quite difficult. But then I’m not a lawyer.
This will exacerbate the decline in numbers of engineers graduating in Australia. I’m not expert enough myself to know just how serious were the mistakes made but it’s obvious that you can work round the clock in shocking conditions, do your very best and then be demonised as criminals. I can’t imagine the health, family and career impacts on these men. Who’d do it? Years down the line the government will be all, “woe is us, there aren’t any engineers.” Oh that’s right, we’ll just poach them from other countries. As you were.
Thanks for this post. I feel for the engineers named for contentiously doing the best they could which unfortunately flooded Brisbane. It’s not as if Brisbane wasn’t going to flood under that rainfall.
billie, there would have been a flood from the water uncontrolled by the Wivenhoe. Just not as bad.
Helen, good point. The engineers got no extra pay for working long hours. The Commission’s Interim report expressed concern about the recruitment and training of suitable engineers and said five should have been on duty, plus another engineer with duties in communication.
I understand that two of the four were no longer available for this kind of gig by July last year. Now the other two have been eliminated from consideration.
Roger @ 4, excellent comment.
John D @ 3, yes, there was an evident clash of cultures and a complete lack of understanding of what it is like to operate under real pressure.
David A @ 5, the manual has been restructured to make accountability easier, but I for one can’t follow it. It seems to me future engineers will be running down a race with sides enclosed and may attend to everything in sequence apart from the big picture. But that’s only an impression from a bloke who was never going to be an engineer.
Helen@7: I’m not sure kids will be looking at things quite the same way. Your point might feed into it, but I get the feeling they’re more picking up on the “what a bunch of useless dicks those engineers are” vibe. And the “lawyers are much better at knowing what to do than engineers are”. Same result, but less nuanced. And I suspect you know my opinion of nuance and the media.
It also directly feeds into insurance costs for engineers. Which doesn’t affect anyone directly, but it makes engineers more expensive to hire. So increasing the pressure to have fewer engineers working fewer hours. Otherwise how will we pay for the lawyers to defend them?
Brian: the people who exactly follow the manual are called technicians, and they’re a lot cheaper than engineers.
Of course, when situations outside the manual arise the technicians will look for guidance. It’s quite clear from the media coverage that they should look first to the media, then to the insurance company lawyers for that guidance.
There are few things more annoying to an engineer than being on site, looking at a problem, and not being allowed to fix it because someone irresponsible has made a rule. Irresponsible in both senses: not responsible for the outcome of their decision; and uncaring about the consequences.
One key difference between engineers and lawyers is that lawyers are not liable for the consequences of their advice, but engineers make actual decisions and have to suck up the results.
Exactly the same stuff happens with fires. This issue will continue to come up, more and more, as the target area for fuel reduction burning increases. There will be less and less suitable weather, there will be less and less experienced fire incident controllers, there will be more pressure on them, and they will say sod this for a dumb job. If they’re held totally accountable for dumb politically motivated policies, and are operating in a risk management world where mistakes have to be accepted as occurring, and are then excoriated for the inevitable failures, of course things will go wrong.
Brian, thanks for this post. As an engineer currently studying to become a lawyer it’s interesting to see the view from someone who is neither. Reading the relevant sections in the report did little to ease my concern about the engineers being the subject of a witch hunt. I found the way the commission interpreted the manual, and the obligations it put on the engineers, to be overly legalistic given the context. In particular section 16.3.5, where there seemed to be a complete lack of understanding on part of the commission about the distinction between an engineering strategy and an operational procedure.
I presume the initial manual was written with risk assessments in mind.
They may have regarded that frequent low level floods is an accepted cost to lower the risk of damage of a much bigger flood. Even if this may have meant that the dam behaved as a ‘flood amplification’ dam for a period.
So if the engineers deviated from the operating manual, they better have very good justification as to why they believe the original manual was wrong (in terms of risk/reward)
And the fact that they’ve successfully used the same less-aggressive strategies many times in the past to avoid low-level floodings is not an excuse either.
You didn’t discuss the role of the dam. I was under the impression that it was built with the original purpose of flood mitigation. It wasn’t built for Water storage but subsequently became used for that role (as other proposed dams were cancelled).
If this is correct then shouldn’t the dam engineers have been letting more water out to try and lower the level to 100% earlier?
OBR, see section 2.2.8 of the Interim Report. The Wivenhoe was designed as both a storage and a flood mitigation dam and the “Full Supply Level” of 67m or 1,165,000 ML was established at the design stage. All that has changed since then is building the auxiliary spillway with three fuse plugs, which was completed in 2005. I understand that with a fourth fuse plug the dam would be able to withstand a 1 in 100,000 flood event.
I presume by that you mean that lawyers are not liable for the consequences of a client’s failure to follow their advice (although even that is not entirely true, since lawyers can be, and have been, held liable for not expressing their advice clearly enough, or not putting enough emphasis on a particular risk even if they did mention it).
I’m not convinced there’s much to be gained by simplistic “engineers v lawyers” finger pointing. As a lawyer, my personal view is that the law of negligence suffers from a ’20/20 hindsight’ problem that too frequently creates unrealistic demands on people making decisions in situations of uncertainty (such as engineers, for example). This is partly the cause of the excessive litigation paranoia that infects every endeavour these days. Another partial cause, ironically, is the quite onerous obligation of lawyers themselves to identify every possible eventuality and alert their clients.
Anderson, I don’t think the Commission’s conclusion that the engineers were always in W1 on the Saturday and Sunday stands up in terms of their own standard of proof.
That aside, there was no reason to be alarmed until three times the rain predicted on Sunday morning actually turned up. Even then that only produced the first peak, which could have been accommodated quite well. The Flood Event Report has figures on how rare the event overall and some of the individual components were. I didn’t try to describe these, but the conditions that turned up were very rare indeed.
The interesting thing will be what happens next time around. The operating engineering team was put together from a number of sources when levels in the dam were starting to be of concern. Given the crap this team of engineers has had to cop one wonders how many engineers with the necessary specialist knowledge will be willing to do the job?
Anecdotal comments suggest that many engineers are unwilling to become mine mangers these days because of the legal exposure and the possibility of going to jail. I think it was Bligh who said that the dam engineers would be paying their own legal fees if found guilty. Few engineers have the sort of money required to cover those sorts of costs.
Brian @6
My understanding Brian (from an impeccable legal source) is that the engineers and the State are indemnified against litigation if and only if the manual is followed. Therein lies the problem.
Tim, if you look at the Commission staff (Appendix 4) it’s lousy with lawyers and law clerks. Assisting Justice Catherine Holmes were two commissioners, Jim O’Sullivan, former police chief, and Phillip Cummins, who I believe was a hydrologist. Unfortunately he was stood aside for the February hearings this year because of an apparent conflict of interest. I think it possibly made a difference, not only at 16.3.5 mentioned by desipis @ 13, which was crucial, but elsewhere.
Hal9000, that’s what it says at Section 16.2 (p443). Section 374 of the Water Supply (Safety and Reliability) Act confers protection from civil liability for the dam operators “for acts and omissions done or made honestly and without negligence in observing the operational procedures manual.”
On the radio I heard that Seqwater carried its own insurance. I don’t know if that’s true or what it means.
Great reading. Thanks Brian.
As one who works 18 hour oncall shifts under high pressure – but not where failures/accidents/misjudgements can destroy houses – I can only sympathise with the damn engineeers.
I have many manuals at my disposal – but neither the time to consult them, nor the faith in their quality to follow them.
Root cause analysis is just often a fancy term for scape-goating.
Hal 9000 @ 20 :
I would be checking that impeccable legal source because insurance (Professional Indemnity in this case) is all about human failings ” acts, errors and omissions”. If the manual was competent and the engineers failed to follow it and this was causal to the damage then the PI insurance comes into play to indemnify them .
Perhaps they can replace the engineers with lawyers if following the documentation is paramount. And they’d prioritise avoiding liability and any future enquiries by lawyers would understand their decision making better than they would engineers.
Wantok, the manual is problematic, which I hope to demonstrate in the next post, which wouldn’t be tamed last night. It kept sprawling all over the place.
paul, the ninth revision of the manual does seem to prioritise accountability. Again I’ll have a bit of a look at that in the next post.
Lawyers will never be able to understand the modelling, which I believe is quite complex, even for engineers. But there may be a scenario where all you need is data collection and inputting with a preset modelling package spitting out the matching gate settings . I’d worry about that because of the possibility of unanticipated events or combinations of events, together with the uncertainties of rainfall forecasts.
Brian, my comment was more sarcastic than serious. I’d hoped it was ridiculous enough for this to be clear.
They remained in W1 for 36 hours in clear breach of the manual. Had they followed the manual then the emergency releases made on Monday/Tuesday would have been much smaller, possibly zero. The unnecessary emergency releases undoubtedly contributed to the size of the Brisbane flood – how much would require detailed modelling.
Then it seems they updated the operating logs nearly two weeks later, and were very economical with the truth.
Open and shut case of negligence.
Bill: If they had stuck to the manual and the weather had turned out as predicted 300 houses would have been flooded and 700 people displaced just to protect the engineers from the sort of claims you made @28. In this case we would probably have had an inquiry into unnecessary flooding with the engineers being scapegoated for not using their professional skills. If you look at the third graph in Brian’s article the clear message seems to be at first reading that it was sometime during the 9th at the earliest before there was any evidence that drastic action was required.
It does seem, however, was that one of the things that was missing was an assessment of weather risk. Brian says:
What appears to have been missing was a weather risk assessment that put a figure on the risk of the weather pattern and rainfall levels being critically different to the “most likely” prediction. This suggests that there needed to be weather experts working 24/7 with the engineers to flag the risk that reality would be much worse than the reality.
During one stage of the flood the engineers were in a position where they had to decide whether to flood some houses (when this may not have been necessary) to reduce the risk of damage to other houses. This should never have been an engineering decision. It is what we elect politicians to do.
Bill@28, there’s a key fault in your (and the commissions) reasoning.
The strategies W1 to W4 only provide guidance as to the relative priorities of outcomes for dam operations. It’s only by applying modelling and professional judgement that one can arrive at a determination as to what action is appropriate. Prioritising an outcome, whether minimising damage to urban areas or protecting the dam wall itself, is a meaningless exercise if there is no actual risk. Where there is no risk to a primary outcome then it would be the other outcomes, presumably the primary outcome of the previous strategy that would effectively guide actions. This means that in many circumstances there would be no practical difference between one strategy or another.
From my general engineering experience, engineering strategies such as the W1 to W4 covered by the operations manual are intended to be used to develop specific operational procedures with limited scope for technical staff or flexible frameworks (including configuring sensors, dynamic software models, processes, spreadsheets, etc) for engineers. The later need to remain subordinate to professional judgement as it’s not feasible to sufficiently consider all possible scenarios to develop more deterministic processes.
Reading the dam operations manual, its obvious the strategies themselves are grossly insufficient to be considered something directly applied during operations, particularly crisis situations such as a major flood. While it might be considered an ideal for auditing purposes, nothing in the manual specifies the recording of the particular strategy selected. In fact the wording and structure of that section of the manual suggest its simply a recording of the current strategies used (potentially based on input from the operations engineers themselves), not a top down specification of the strategies that ought to be used. In such circumstances the strategies in the manual are likely to be gross simplifications of the complex issues of combining a large amount of data into qualitative assessment and forming a judgement about appropriate action. Attempting to consider the strategies as defined in the manual as authoritative in such circumstances would be irresponsible.
The more important issue to record, from an engineering perspective, would be the point when circumstances cause the primary outcome of the relevant strategy to be under risk and begin to drive what actions are taken. It’s in this context that the report at 6pm on the 8th (~12 hours into your 36 hour window) and its reference to the “application of W2″ should be read and understood (see section 16.7.2). It indicates to me that the engineers were already prioritising the primary outcome in W2 (if not W3) but at that stage had made the judgement that the outcomes were not at risk. By “application” I interpret it to mean changing actions (dam releases) to protect outcomes, to apply it in the real world, not changing the priority of outcomes in considering actions.
This is another key point where I differ with the naive “plain reading” and legalistic approach of the commission. It’s also worth pointing out that judging from the report the commissions took a view that is contradicted by the views from 3 of the 4 experts giving evidence. Importantly a breach of the manual doesn’t necessarily mean they breached their duty in a negligence context; although the manual is potentially persuasive in determining what they had a duty to do.
Further to whether they actually breach the manual, there is nothing in the manual that dictates how much water to actually release. While all strategies involve prioritising one particular outcome, it’s explicitly stated in the manual all other outcomes must continue to be contemplated. It’s quite possible that (even if they were operating under the ‘wrong strategy’) that operating under the correct strategy would not have resulted in material difference in dam releases given the information the engineers had at the time. Importantly for showing causation in a negligence case, this is a question the commission appeared to not even attempt to answer. The commission’s report doesn’t accuse the engineers of causing damage, it’s accuses them of something akin to an “engineering thought crime”.
John D, what you say is correct, I think. As significant rain had already fallen by Monday to create the first peak Tibaldi was still able to promise the BCC to keep flows at Moggill at less than 3,500 cumecs, which does cause some damage, as you say, but is well within 4,000 marker the prescribed. What Bill says about “unnecessary emergency releases” is simply rubbish.
Also not even the Commission says they were in “clear breach of the manual” for 36 hours. What the Commission says is that on the balance of probabilities with no other explanation being reasonable they were in breach. I disagree, but I’ll talk more about that in a post to come.
This is offensive and unacceptable in a blog comment:
You cite no evidence for this assertion. What I know is that two weeks after the event Tibaldi in examining the log of what happened realised that they were releasing too much water on Saturday 8 Jan to comply with the conditions of W2. They changed nothing in the log. What they were obliged to change was their account of what happened in relation to which strategy applied.
desipis, I’ll think about your long comment later. One point. The manual dictates in each strategy except W4 a maximum allowable release, but not a minimum. In W4 they can of course release whatever is necessary to safe guard the wall.
Very well put Desipis. This part really gets to the crux of what the manual was all about:
In these terms an examination of the third graph above suggests that the dam was being operated within the manual guidelines given that even engineers cannot predict the future. My only comment is that the flows from the dam might have been raised closer to the max allowed by W1 priorities a bit sooner. However, keep in mind that even engineers cannot see into the future, the high inflows started on Sunday and, until the second surge of high inflows started on Tuesday it looked as though the dam would be brought back to normal levels without exceeding the W1 max flows.
This is the third major disaster inquiry that touched on areas where I have had some relevant experience. In each case my conclusion was that the outcomes were flawed because the inquiries were run by lawyers who had no relevant experience.
The first of these was the Esso Longford gas explosion Two people were killed and Victoria suffered from dramatic gas shortages for quite some time. Basically, the explosion occurred because the temperature in the unit that exploded got below the embrittlement point of the material from which the unit was made. (In other words a design fault – either the unit should have been built from material that would never reach its embrittlement point and/or unit should have been protected by rupture disks that would burst at the appropriate temp/pressure combination and direct the escaping gas to the flare. It is also worth noting that the particular problem hadn’t occurred since the plant started operation 25 years earlier.
So it was a bit startling to see in the papers that one of the main recommendations was that “the control room operators be better trained”. Anyone who has operated a control room when things start to go wrong understands that you cannot depend on the operator realizing how serious what is happening is or the correct response. But this is what the lawyers concluded. (As a matter of interest the operators had been struggling with hydrate build-up all day and probably saw the problem as “keeping the plant running” when problems started in the unit that failed.
The second one was the inquiry into the black Saturday fires. The problems with this inquiry were discussed at length in
this LP post The inquiry reinforced the case for having someone other than lawyers running inquiries in areas where they haven’t a clue about who is responsible for what during an emergency and the practicalities of large scale evacuations during bush fires.
Now this one. Miles better than the Black Saturday investigation but, as Desipus put it so well they didn’t understand what the manual was and wasn’t and the relationship between the manual and what the engineers were really supposed to be doing.
Brian:
Reading through the strategies (particularly W1A to W1E) the alignment of the “maximum release” and the goals of limiting combined flows gives me the impression that the maximum release is simply where the flow from the dam itself (ignoring any other sources) is enough to cause the goal to be lost (i.e. water over the particular bridge). Once you’re at the point where the flow from the dam itself will cause a crossing to become untrafficable it’s pointless having a strategy where the primary purpose is to maintain the trafficability of that crossing. It’s the opposite to the situation I described above, where instead of lower objectives governing outflows in the higher strategies, you could have higher objectives governing outflows in lower strategies effectively rendering the strategy obsolete.
I recall when reading through the report that somewhere one of the engineer’s made the point that the strategy would be (in part) determined by the outflow of the dam (despite the apparent contradiction the commission pointed out). I think this is what he might have been getting at. If you’re already releasing water from the dam to deal with risks to the higher objective of protecting Moggill or Lowood (or urban areas) over the course of the flow event, it’s an academic exercise to determine whether the dam level means you’re operating under W1 or W2 (or W3) because making some lower objective “primary” doesn’t impact the fact that the higher objectives would govern releases. If you’re in a situation such as a major flood event I think it’s reasonable to deal with such distinctions after the fact (if at all).
I think there’s certainly a case to be made for improving the manual. However, given it was likely written by engineers for lawyers it’s not all that surprising it ended as much of a confusing mess as the commission’s report on the matter.
John D, thanks. Since I’ve begun to study law I’ve been considering the ability of judges (as essentially lawyers) to deal with complex technical issues. It wouldn’t surprise me if the issues you identify with such inquiries extend to over the whole judicial system. I think there might be an argument for creating independent judicial bodies for major academic fields consisting of technical experts who are responsible for determining questions of fact (or standards of professional conduct) in relevant cases, while leaving matters of law to the traditional “law” judges.
John D @ 33, the point from desipis that you highlight is a good one. During Saturday and early Sunday the dam was only just above 68.5m (15 cm at the most) and going nowhere. At this time the situation reports mention the impacts in millimtres in some cases down to the Port Office, with reference to the tides, but the main focus is naturally on the Fernvale and Mt Crosby Weir bridges which were next in line.
BTW the maximum flow of 1,900 cumecs in W1 is only theoretical, and would only be possible if no water was coming from elsewhere. The real limiting factor is the Mt Crosby Weir Bridge, which goes under at 1,900 cumecs. At 8am on Saturday there was 550 cumecs coming in from the Lockyer Creek.
Keeping some bridges open wasn’t a bad idea. the Fernvale Bridge (2,000 cumecs) is on the Brisbane Valley Highway. From memory at the time it was the only way to get to Rockhampton from SEQ until it too went under.
desipis @ 35, to be frank I skipped all that detail about W1A to W1E. Looking at it though, I think the maximum release flows are all theoretical, assuming no water from elsewhere. In practice I gather the inputs to their models include stream gauges at various points in the Wivenhoe catchment and other streams such as Lockyer Creek, so that the can see in advance what is coming down and make predictions when crossings are going to be untrafficable.
They have to allow time for someone to get out there and put up the barriers and the signs. In some cases, eg Fernvale, I believe they allow for emergency health evacuations also. This came out because there was impatience about how long it took to close the higher level bridges after a decision had been taken to do so.
The main game IMHO is the first page of W1, W3 and W4, with levels of 67, 68.5 and 74m respectively, together with stream flows of 1,900 cumecs at Mt Crosby Weir Bridge and 4,000 at Moggill.
W2 is redundant. The rest is at the next level of detail.
desipis, further to your @ 35, the point the engineer made about the dam release determining the strategy related to W2, which says, in part, that the intent is to keep the dam releases below the natural flow at Lowood, excluding dam releases.
If you read the whole chapter again ask yourself what anyone around in 2011, not just the four engineers, knew about W2. I think they knew that it was transitional from W1 to W2 and that it introduced 3,500 cumecs at Lowood as a limiter, along with 4,000 at Moggill. I think they clean forgot about the business of limiting releases to the natural flows at Lowood and Moggill, otherwise they would not have thought that W2 was in use at all, ever, during the event.
When the engineer said we were already releasing 900 cumecs at 8am when the natural flow at Lowood was 550, therefore W2 was unavailable, the Commission said, wait a minute, you can’t use existing release rates as a reason, you could intend to reduce the releases to less than 550, so you still have to make a choice, which you would do according to what is appropriate in the conditions.
The rejoinder is that you would only consider it appropriate if the rain had stopped in the Wivenhoe catchment, but was belting down in the Lockyer and you wanted to let it past. But you wouldn’t choose W2 because you could already do that under W3 and as Ruffini said (p448) there were other practical reasons for not wanting to ‘jump into that space’. W2 is redundant, and the Commission should have seen it as such.
That point about the relative rain in the catchments was made to them, but they were too intent on finding fault with the engineers to understand its true significance.