Guest Post: Mem – Extrapolating Backwards or the Case of the Missing Dam

During the millennial drought (2006 -2010) there was great concern that Melbourne might run out of water. The Labor government in Victoria pushed for the construction of a desalination plant.

Graphs and statistics were presented showing historical records of Melbourne’s water supply and usage, as well as projections for the future. All emphasized the gravity of the problem not only in the short term but also in the context of future population growth. The Climate Change (Global Warming) movement had just begun to peak as a broad moral crusade.

Many of us have forgotten the daily messages about water restrictions and the doom and gloom scenarios run in the media. There was even a countdown clock to Armageddon showing when we would run of water, that appeared daily in The Age.

In 2007, Prof Flannery, Australia’s Chief Scientist declared:

Even the rain that falls isn’t actually going to fill our dams and river systems.

Any consideration of building another dam was out of the question for a government tied to the vocal Greens party. Flannery’s prognostication added weight to the government’s case.

In this context the desalination plant was approved in 2009 at a construction cost of A$3.5 billion and a contractual arrangement (involving several parties signing up to a public private partnership (PPP)) for an operational cost of A $5.7 billion until 2039. It commenced operation in 2012.

What still intrigues me is that one of the main graphs used to show the state of Melbourne’s water supply and to promote the case to the public for the desalination plant was unusual, to say the least. I will explain.

The Thomson Dam was built in the 1970’s and was first filled in 1981. It more than doubled the combined capacity of all the other dams supplying Melbourne, so its impact on Melbourne’s water supply was enormous. This should have been depicted by a gigantic peak in the graph commencing 1981 but there wasn’t even a blip. How could this be so?

I wrote to the CEO of Melbourne Water and was advised that it had performed an unusual technique I’ll refer to as “extrapolating backwards’; that is, they recreated historical data using a model to project backwards, and in this case to fill a not-yet-constructed dam with estimated rainfall back to 1901. According to the graph the Thomson Dam was filled before it was built! Yes, believe it or not, Melbourne had more water in its dams ten, twenty or fifty years before the Thomson was built. The graph remained on the Melbourne Water website until very recently (30/09/2021) and is now replaced with an equally deceptive graph.

The current graph is located in a section called Historical Water Storage Levels. The graph itself is untitled. The vertical axis is labelled percent full and the horizontal axis is labelled with years running from 1940 to the present. Looking at the graph one could easily be deceived into believing we now have less water in our dams than we had in 1940 and that yet again the Thomson had absolutely no impact on supply. Quite a feat given the Thomson came on stream in 1981 and more than doubled Melbourne’s total dam capacity!

You can view this graph here, so judge for yourself. Drop down to historic water levels and click on all years to see graph.

N.B. As at (4/10/2021) Melbourne’s dams contained 1,812,175 ML and were 84.4% full. The Thomson Dam contained 1,068,000 ML and was 84% full and made up 58.9% of the total water stored.

For the 2021-22 financial year an amount of 125 gigalitres of water has been ordered to supplement supplies as required. Usage to date is provided here.

All data for this post was sourced from the Melbourne Water website.

22 thoughts on “Guest Post: Mem – Extrapolating Backwards or the Case of the Missing Dam”

  1. I suppose the intriguing question is, “Why do they deliberately lie and manipulate?”.
    They know what is depicted is not only wrong but made so by their own actions, but to what purpose? People do not do these sorts of things on a whim or without benefit to themselves in some way.
    However much you believe in Climate Catastrophe, there is no logical reason to manipulate past data, you only do this if you do not really and truly believe catastrophe awaits. You would want full disclosure of the reality of past actions that, by definition, caused the present crisis.
    As I say, intriguing.
    Anyone with answers? (Saying they are stupid etc won’t work. Whatever else they are they are not doing this simply because the don’t know any better.)


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  2. I suppose the intriguing question is, “Why do they deliberately lie and manipulate?”

    Cui bono?

    …the desalination plant was approved in 2009 at a construction cost of A$3.5 billion and a contractual arrangement (involving several parties signing up to a public private partnership (PPP)) for an operational cost of A $5.7 billion until 2039.



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  3. Reminds me of the old Canberra accusation against part of a particular agency.

    It was said that they kept three sets of books. One to deceive the Minister, one to deceive the parent Department, and one to deceive themselves.


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  4. This obfuscation ties in with Mater’s thesis – presenting statistics in multiple formats/varying criteria to diffuse analysis.
    Roger is right – there is a purpose. Nefarious I’d say.


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  5. The desal plant was a panic reaction to a pre-election opinion poll showing that the public regarded the Bracks government as do-nothings. (As if that’s necessarily a bad thing for a government, but so be it.) So they had to show, before the election, that they were fully committed to spending the maximum possible amount of taxpayer funds. (They got re-elected, btw, which illustrates the mentality of the average Victorian voter.)
    Then the questions started.
    The government commissioned a report from Sinclair Knight Merz which has never been released in full to the public claiming that the desal plant was a better option than a dam on the Mitchell River. The limited extracts that were released purported to validate that claim, but it couldn’t be disguised that SKM hadn’t been asked to review desal v dam in general, SKM had been given two highly dodgy ridiculous planned to fail dam proposals (mainly putting the dam in totally the wrong places) and asked to compare them to a desal.
    So no degree of dishonesty in government’s presentation of water supply facts would surprise me.


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  6. Roger W says:
    October 5, 2021 at 12:06 pm

    I suppose the intriguing question is, “Why do they deliberately lie and manipulate?”.
    They know what is depicted is not only wrong but made so by their own actions, but to what purpose?

    Fundamentally… a defeatist death view of humanity and a primacy to view humans as an evil organism on the face of gaia.

    They are fkd in the head.

    There is enough water that falls on the east slopes of Australia that could turn the interior into an Eden and support who knows how many millions of people, whether they lived there or not.

    The tunneling that was proven with The Snowy Mountain Irrigation Scheme actually proved it.

    Let alone the development in tunneling technology that has occurred ever since.


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  7. Let none call it corruption…

    Tertiary education workers in Australia loom as the biggest winners from the Victorian government’s decision to order water from the Wonthaggi desalination plant.

    Workers in the education sector, through their industry superannuation fund Unisuper, rank as the largest shareholders in the company that is contracted to finance, operate and maintain the Victorian desalination plant; Aquasure.

    ….
    None of the shareholders in Aquasure would comment on Monday, with one telling Fairfax Media that they were bound by the Victorian government not to discuss the desalination plant publicly.

    ..
    AMP Capital acquires additional stake in desalination project

    Squeal like a pig Vicco taxpayers, squeal I say….

    A Victorian taxpayer, 2021, colourised and moving pictures


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  8. Re Roger – Cui bono?
    I assume the actual public servants did not benefit financially, it was the builders of the de-sal plant who did, so not sure of this explanation.
    But this makes the answers from Timothy Nelson, re politicians, and thefrollikingmole, re unisuper etc, the more rational – plus, naturally, Flying Pigs analysis of greens etc.

    What fun times we live in. Was it ever thus or was there a Golden Age of rational, moral government?


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  9. What fun times we live in. Was it ever thus or was there a Golden Age of rational, moral government?

    No.

    History is all about clashing forces. Now and then, the latest clashings result in periods of prosperity and scientific progress. Those of us who are lucky enough to live in them should rejoice. We could have been Baldrick.


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  10. Re Roger – Cui bono?
    I assume the actual public servants did not benefit financially, it was the builders of the de-sal plant who did, so not sure of this explanation.

    We’re dealing with a web of interests here, Roger.

    The public servants would have been kindly asked to massage the data to achieve the required outcome to justify building the plant, with all the profits and kickbacks subsequently delivered for those involved.

    Nobody does corruption quite like Australia.


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  11. Oh…and government gets to spruik its green credentials, the environmental impact of the desal plant nothwithstanding, because after all it’s not a dam and so it gets a free pass.


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  12. thefrollickingmolesays:
    October 5, 2021 at 4:48 pm
    Even better Roger, if it looks like the plant isnt needed a few more ‘environmental flows” can be ordered.

    Its a self licking ice cream cone of dodgy money.

    You and others above made my time in putting this post together worthwhile.


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  13. Mem, do you know how long it took to fill the Thomson and was it in use whilst it was filling? Looking at the graph linked to, am I reading it correctly that it shows June/July 1984 shows a large fall in the % fall in the total capacity of the MMBW Reservior system?


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  14. Mamansays:
    October 6, 2021 at 11:29 am
    Mem, do you know how long it took to fill the Thomson and was it in use whilst it was filling? Looking at the graph linked to, am I reading it correctly that it shows June/July 1984 shows a large fall in the % fall in the total capacity of the MMBW Reservior system?

    The archive that showed the level of the thomson filling which was available at Melbourne Water is no longer accessible! I read it some ten years ago and from memory it was first full to capacity in 1992 bearing in mind that the engineers had allowed for a 15% margin for safety, so that full would mean 85%. This has, I think, been recently converted to 100% for reporting purposes.
    I came across this on the google but no link.
    “On 31 July 1984, the newly-built reservoir was officially included in Melbourne’s total water storages, more than doubling storage capacity. Still virtually empty when factored in, its size dragged down the city’s storage levels from 65% to 26% overnight. It has been full three times: 1992, 1993 and 1996.10 Sept 2020”.


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  15. 🙂 Mem, thank you for the link to the videos of the construction of the dam. Such simple times, employee safety: hard hat and boots.
    About the dates, was just surprised construction could be that fast. Again, in the first line “During the millennial drought (2006 – 2010)” did you mean 1996-2010? Or was that a reference to when the government began negotiations?
    An interesting paper came out in May this year: monash.edu/news/articles/victorias-water-catchments-may-not-recover-from-drought-study. It’s in the journal ‘Science’, author, Dr Tim Peterson, and it’s just more statistical modelling that might be ‘entertaining’. (I don’t have a subscription)
    Construction videos are much more interesting.
    Some years back we had a look inside and over the 3G Dam – mind blowing!


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  16. Mamon
    If I ever write a book I would like you to edit. You have taught me much. The story nevertheless holds up. And was worth telling. Thankyou for your eye for detail. Cheers mem.


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