Matters of interest

Author : J. V. Hodgkinson F. C. A. Chartered Accountant : Aug 2006 to November 2013    

The principal thrust of this website is
FLOOD PROOFING BRISBANE from damaging floods to the point of extinction. MITIGATING flooding in Ipswich and Gympie. Putting REAL MEANING into "Drought proofing SEQ" and ensuring our water supplies by natural means well into the future

This is my review based on official statistics and documents. It is done in conjunction with Ron McMah, grazier of Imbil and Trevor Herse, retired of the Gold Coast




The following is examination of material that was interesting at that time. It is kept in the website for information.


A Click will give you an alternative view of why our dams depleted in the first place. If it is not understood, then the solutions offered have no real base. It looked like a "drought". All around Queensland was in drought, and the waters in the dams were at their lowest level since the commissioning of the Wivenhoe in 1986. So what was it that caused the depletion?

It was the random nature of large events outlined by Mr Drury of SEQWater at the introduction above. 300mm in a few days is a flood capable of filling the dams from scratch to overflow but on the other hand the same rain distributed over 3 months of 100mm per month is  a comparative trickle. They pay no attention to the time of the year and occur on average every 3.7 years.

As we are seeing at present, the dams are too small to control the water supply for the ecology and ourselves. The Borumba dam, just over the hill in the Mary Valley, is currently quite small but can be expanded to almost twice the size of the Wivenhoe.

Whose water is it?

In March 2007, the State Government legislated that 66% of all water that passes through the Wivenhoe/Somerset dams must reach the Brisbane River mouth. That means that only 1/3 of the water in the Wivenhoe/Somerset dams is for us and 2/3 for the ecology. Click on water share for additional information. It will give one a better understanding as to why there is no lifting of water restrictions.


This website, developed since 2007, has reached a point where, with dams full, it may be useful to reflect on events so that the acknowledged errors of the past may be avoided in the future. Failure to do this in the period 1989 to 2001 following the cancellation of the Wolfdene Dam, produced a catastrophic period 2001 to 2007. It was incorrectly blamed on a multitude of things but the main underlying excuse was the non-existent "drought" in the catchments, proof of which will follow.

This examination covers a wide range of topics that includes such matters as:-
* Determination of our water supply including high rainfall events known by SEQWater as "Uncommon events". Mr Drury's relevant statement: " You do need large "Uncommon events" to fill large dams. You do not fill them every year."
 * Impact of our main water supply "Uncommon events" on Dam levels, 
* The "drought" of 2001 to 2007, 
* Cancellation of the Wolfdene Dam, 
 * The use of "decile maps" distorted by statistical aberration to convince us of the existence of that drought,
 * Population increase normal and predicted. No sudden up-lift. 
* The certainty of 2001 to 2007 type period happening being overlooked with the resultant high cost and expensive alternatives not now required, 
* Rainfall in the context of Climate Change, 
 * The Traveston Dam debacle and the ignored alternatives, 
* The use of statistical aberrations by including the floods of 1890 and 1893 which significantly and permanently affect the allocation of water between us and the ecology. The use of this aberration, if allowed to stand, will eventually force us to use a further three highly expensive desalination plants to compensate. The official data from the Department of Natural Resources and water that support this statement is contained in Water Share

Click on subject 

* "Drought" of 2001 to 2007
* Uncommon events are our main water supply
* Consequences of the miss-interpretation of the action of these events
* Traveston Dam and alternative proposal
* You cannot take water out of the Wivenhoe/Somerset system! (true or false?)
      1. Yield of the Wivenhoe/Somerset.
      2. Complications introduced by the Water Resource (Moreton) Plan 2007 enacted in March 2007.


"Drought of 2001 to 2007"
This is sometimes known as the "Millennium drought".

The Bureau of Meteorology tab offers the following:
 * E-mail from the Melbourne office confirming that rainfall in the catchments for the years 2004 to 2006 was close to 80% of theBOM_e_mail_25_08_06_Page_1.jpg (126163 bytes) long term average 1961 to 1990. 
 * Summary of Bureau rainfall stations in the catchments that show the 4 summer months were within a few percent of that long term average. They receive 53% of all rainfall. The 20% deficiency was in the low-flow non-summer months. 
 * The use of the "decile" map 2001 to 2006 showing "lowest on record" when the percentage map that I had them produce for the same per showed 80% of the long term average for the same rainfall and period.
  Due to the statistical aberration that rainfall in the catchment for 6 year periods had never been lower than 80%, naturally the "decile" map recorded 80% as "lowest on record".
Photo : E Mail from Bureau of Meteorology

The Decision Makers Tab offers the following:-
* Promotion by them of the "Decile" map as "proof" of drought conditions in the catchments and ignoring the "percentage"Brochure matched with Percentage.jpg (122322 bytes) map. There is no question that most of Queensland was drought declared at that time.
* Six year periods of the twentieth century show that there was nothing unusual in the 2001-2007 year period. Those to the left of centre are without a high rainfall "Uncommon " event and those to the right of centre included a high "Uncommon" rainfall event.
Photo: "Percentage" map that corresponds with "drought" map.

The Federation Drought Tab offers the following. It is supported by Rainfall 2001-06:-
* Comparison of the Federation period 1898 to 1903 with the period 2001 to 2007. It was carried out by the QCCCE (Climate Change Centre of Excellence) on the basis of "rainfall" as they concluded that a "hydrological basis" could not be achieved. You will see that:-
* On the basis of "rainfall" it fails because of the lack ofFederation_drought.jpg (241659 bytes) concentrated rain in the "Federation" period and
* It confirmed that the rainfall in the catchments for the period 2001 to 2006 was 76.2% of the long term average.
* The IQQM model is used to explore the hydrological pre-development flows in the Federation" period contradicting the QCCCE advice that it was not possible. The model is enshrined in law (Water Resource (Moreton) Plan 2007).
Photo : Comparison of rainfall

What was common to both periods was the absence of "Uncommon events" being highly concentrated rainfall as outlined above. They both exceeded the 3.7 year average of these events.

The QCCCE is an organisation that is difficult to deal with. No one person appears in charge and my enquires seem to end up in the Department of Environment and Resource Management or its fore-runner Departments with different names. That Department is also responsible for the IQQM computer model which must, by law, calculate the hydrological pre-development flows.

The Depleted Dams Tab Assists in drawing together the above and adds additional information.
* Rainfall stations in the catchments that have existed for approximately 100 years are examined to view to 4 summerSummer V Non Sum Percent.jpg (197951 bytes) months December to March and the 8 non-summer months. The percentage is 53% to the summer months.
Photo : Summer rainfall V Non-summer




* Population growth. There is no sudden uplift that caused the dam levels to drop. Population was predictable and wasPop_graph_4.jpg (86814 bytes) predicted.
Photo: Population growth


Climate change can be examined by combining rainfall in 30 year lots similar to the method used by the Bureau of Meteorology in comparing rainfall. Both catchments are shown. The situation appears constant.

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Uncommon Events are our main water supply
Being large scale rainfall events such as monsoons, Cyclones and large scale rain depressions.

The Uncommon Events Tab offers the following observations.
* Rainfall comparison of 5 rainfall stations in the catchments comparing the recent February/March 2010 rainfall with the rainfall of the other major inflows in the life of the Wivenhoe Dam.
* The inflows in the life of the Wivehoe now verified by the Government IQQM computer model.
* The dam level graph of the Wivenhoe Dam highlighting the major inflows.

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Consequences of the miss-interpretation of the action of these events

Additionally the Uncommon Events Tab offers two main photos that point to miss-interpretation of their actions.

*The second last photo, being the Wivenhoe Dam levels, shows that the cancellation of the Wolfdene Dam was decided at a time when the dams were full by the April 1988 and AprilWivenhoe Uncommon to 2009.jpg (86136 bytes) 1989 Uncommon Events. This is an admitted error that ultimately cost billions of dollars and disrupted peoples lives.
* The same photo shows that "Summer rainfall" was inadequate by itself from as far back as 1992. It shows how dependent were upon "uncommon events"
* The last photo is of the frequency of "uncommon events" compiled from flood gauges and flood information available on the Bureau Of Meteorology Web-site. While the average of these events is 3.7 years, with most below this average, it is a mathematical certainty that those above will extend for several years above the 3.7 year average.
Photo : Dam levels during life of the Wivenhoe dam

This was the root cause of the depleted dams in the 2001 to 2007 period. A gap of six years was experienced. A convenient statistical aberration was use to justify the term "drought" thus hiding from view-
 * the error of judgment by not providing for such a period and
 * the understanding of what was needed to correct the situation.  

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Traveston Dam and alternative proposal

* This three stage dam was the main thrust of the answer to "drought-proofing" South East Queensland.
* Its ultimate demise was attributed to two fish and a turtle. My understanding from the people of the Mary Valley through their publications, was that it was much more than that and is now of historical significance. 

* Mr Ron McMah, grazier of Imbil, put an alternative to the then Deputy Premier Anna Bligh to raise the Borumba Dam from the present 46,000ML capacity to 2,000,000ML and add a pipeline from it to the Wivenhoe/Somerset for storage as the capacity of the Wivenhoe/Somerset was inadequate to hold the flood waters of that system. She agreed at a public meeting at Gympie, that was the way they would proceed if it "stacks up". 

* The proposal and the appendix to it has been lodged with the Queensland Water Commission who called for submissions of the draft South East Queensland Water Strategy. While the Traveston has been scrapped it still has relevance in elimination most, if not all, of the proposed desalination plants

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You cannot take water out of the Wivenhoe/Somerset system! (True or false)

The approach of the Queensland Water Commission to the McMah proposal made it doomed to failure in a very short time. The Hydrologists and Engineers were both advised that there was no water available from the Wivenhoe/Somerset system. They prepared their report on that basis excluding the necessary Wivenhoe/Somerset and pipeline. The Engineers did provide a costing for a similar size dam wall approximating a dam of 2,000,000ML which was useful.

* There are two possible reasons for that advice being :-
   1. The yield of the Wivenhoe/Somerset was insufficient or
   2. The Water Resource (Moreton) Plan was to be introduced to Parliament and it became law 3 months after both the Hydrological and Engineering assessments had been completed. 

We will cover both as they are both relevant.

1. Yield of the Wivenhoe/Somerset.

* This was determined by SEQWater, the dam managers in 2001 and 2002 annual reports at 446,900ML Currently the "allocations" are 286,000ML for our use in SEQ. This leaves 160,900ML available and no requirement for desalination plants.
* However, the QWC in their draft strategy arrived at 373,000ML. This 87,000ML discrepancy has not been explained. Yields_Annual_SEQWater_web.jpg (114473 bytes)My question to the Department of Environment and Natural Resources was  explained as an "allocation". It clearly is not. However, they are uncertain of maintaining even this 373,000ML yield in the face of their belief in the "Millennium drought". They have adopted a "stochastic" approach which the cynics in Wikipedia describe as "best guess in the circumstances".


* The McMah proposal explains that in only two short periods in the last 120 years did this condition occur and is quite easily handled in the Borumba Appendix. This then releases 83,000ML and contravenes the statement "You cannot take water out of the Wivenhoe/Somerset system".
* We will also see that the same method will provide a further 50,000ML available and identified by Government engineers.

2. Complications introduced by the Water Resource (Moreton) Plan 2007 enacted in March 2007.

* Minister Stephen Robertson made it clear to me in his letter of the 6th August 2009 that the principal constraint of the proposal was that 66% of all water in the Brisbane River system had to reach the Mouth of that River.
He referred to the Technical Advisory Panel's advice. 
* Our share of the water calculated by that panel is set out in that section. The calculation is based on two things: 
1. The percentage of the pre-development flows and 
2. The years used to calculate the average flow known as the "Mean Annual Flow (MAF)".

While the 66% is accepted, the use of the calculation period of the 111 years 1890 to 2000 appears to dissent with their own literature. It includes the floods of 1890 and 1893 which when compared to a base of 113 years 1894 to 2006, we find that the use of that now permanent percentage based on 1890 to 2000 converts to 75% for the ecology and denies us 130,568ML annually or the equivalent of 3 desalination plants of the Tugun size.

This is more fully discussed on Water Share including graph of the pre-development inflows which clearly shows the distortion created by these two floods.

Correspondence with two of the most senior professors is ongoing. (June 2010)

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