Wivenhoe Somerset Dams Rainfall

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


Bureau Meteorology
Decision makers
Initial Statistics
Dam Statistics.
Wolfdene Dam
Climate change
Uncommon Evt.More
Rainfall deficiency
Summer V NonSum
Wivenhoe Dam
Rain 1986-2006
Federation drought
Rainfall 2001-06
In public arena
Traveston  Rain
North Pine Dam
Hydrology Mary V
Borumba Dam
Final Solution & EIS
Home Page 2
Correspond. Index
Brisbane River 66%
Mary River 85%
Environmental Flows
Pumping Storage
Additional Reading
Depleted Dams
Uncommon events
Borumba Proposal
Borumba Appendix
Water Share
Matters of interest
Trev Herse
Flood Volumes
Flood Inquiry
Water cost
Lower Wivenhoe
Storms Rains
Wolffdene dam
System Block


The Newman Government recently displayed its hand in relation to flood minimising Brisbane, Ipswich and some of the Mary Valley. Minister McArdle joined the list of "you cannot flood proof Brisbane". The List included Premier Newman and Lord Mayor Quirk. The "can do" people of water have changed into "cannot do" people.

One would notice that the dams presented and the raising of the Wivenhoe dam wall would not produce a single drop of water with the exception of the Borumba dam expanded. The expense involved in minimising flood in Brisbane and Ipswich was not clarified

The approach of the Department responsible for our water supply is to determine the requirements into the future. Then determine the supply side. On balance that is the way to go and follows in the footsteps Of the ALP Minister Hon Ed Casey when announcing the cancelation of the nearby Wolffdene dam. for FULL STATEMENT Click

However that is not the way the Wivenhoe/Somerset system works. You will come to understand that normal rain and storms have little to nil bearing on the state of our dams. It is Seqwater's Mr Drury states that it requires large "uncommon events" to fill these large dams and they do not come every year.

For a revue on how the system works click here

You will notice that there are six periods in the last 150 years where the 5 year mark is exceeded. Five year sees out the capacity of the Wivenhoe/Somerset. Therefore there are two periods of 11 years where we will be able to play cricket in the dams for the last six years.

Being sensible, our current requirements are 286,000ML annually and that will require six desalination plants. I understand our only available desal plant is up for sale.

The way I see it those who run the dams and those in charge have not learnt the lessons of the 2001-2007 period

Terri Benson E Mail 29th July 2013

“I am happy to discuss an independent engineering review, the scope and how you would see this progressing. Please feel free to call me or we can set up a time to meet.”

 Mr Noel Faulkner, Chairman Seqwater 13th September 2013 Letter and email

 “I understand Terri emailed you on the 29th July 2013 with an offer to discuss and independent review to scope and seek your input, to date she has not received a response. I would encourage you to meet with Terri again to discuss and independent review……..I have asked that Terri keep me up to date on this matter”















2nd December 2013

The statement at the top of this page dated August 2006 unfortunately holds true today. The last seven years has enabled me to accumulate firm information to review and confirm the course of those years 

I have come to understand that this conundrum is more difficult to assess than I imagined because it countermands the evidence of our own eyes.

However if the Conundrum of our water supply through the Wivenhoe/Somerset is understood, the answer to so-called "drought" and "flooding" can be achieved by natural means and with far less cost as I have outlined under section (B).

The conundrum occurs often

The Conundrum for the 2001-2007 period, which is representative of a large number of similar periods since records were kept, is difficult to see unless you have all the data. I have laid this out for your examination. You will see that mathematics/arithmetic/statistics is the principal guiding light and their need surpasses all other disciplines.

The conundrum is essentially "in the 2001-2007 period, why were our dams depleted to almost empty when the BOM rainfall stations in the catchments showed 99.1% in the Wivenhoe and 91.4% in the Somerset of the long term average of the rain producing Summer months December to March"? Those four months receive more than 50% of all rain since records were kept (see a little later)

The surprising answer is that rainfall and the state of the dams have little in common. You will observe why and the abortive attempts by our water guardians to make them match. The understanding opens up a totally different and less expensive approach.

I will attempt to explain further putting the pieces together for your examination. I have added (A) a short review of our water supply and (C) being our progress to date with Seqwater dam controllers.

(A) Short review of our water supply in the Wivenhoe/Somerset Follows: Appearances can be deceptive.

(B) Our proposal for severe "drought" and "flood proofing: Brisbane and mitigation in Ipswich and Gympie Click to proceed directly to this point and skip  the water supply review.

Our progress to date: Points that Seqwater dam control members saw as important at our meeting on the 13th June 2013.
* A flood "five times greater" than our last known major flood of 1893 was their initial point. A flood of that magnitude would wipe out Ipswich and Brisbane CBD and surrounds.  I subsequently sought clarification by the Chairman of Seqwater as all people of SEQ should be aware of such a flood of biblical proportions. He had a different and more practical view.

* They produced a longitudinal Profile of the pipeline which, at first sight, made the pipeline appear difficult and expensive based on quickly transferring flood water. They put it back to us to prove otherwise. However, their predecessors already had in their possession two engineering backup profiles that tend to support the pipeline from Borumba Dam (expanded) to Wivenhoe as an economical unit capable of delivering what is required. 

Click for further information on this section

(A) Short review of our water supply

(1) Topical graphical features of our water supply

While most of our dams in SEQ are fed by rivers that flow directly into the east coast Pacific Ocean, there are two that have their source in the coastal ranges but flow west. 
The Brisbane River also flows into the ocean but its main tributary above the Wivenhoe dam is one of two that that have their source in Moreton resources.jpg (141612 bytes) the same mountain range but flow south west (Stanley River) to join the Upper Brisbane River at Wivenhoe and North West (Mary River) to eventually come out Harvey Bay. Flowing West occurs through some geological anomaly. Mary Val and Somerset Summer.jpg (234529 bytes) The rivers should have conformed and flowed East according to a CSIRO Geologist with whom I have had many discussions. Notice the common rainfall pattern
The result is that the Stanley River is our main water supply with a catchment of 1503 sq klms. All other tributaries are below the dams. As the catchment is on the Western Side of the range, there is a somewhat lesser supply of water. 
The other arm of our water supply is the Upper Brisbane River. It is  above the dams and has a catchment three times larger at 5,554 sq klms. However it receives a much reduced rainfall and provides less flow than the Stanley. This statement, although generally accepted, can to be tested on two counts. 1. Lesser rainfall can be seen at normal rainfall 2. In the wet season December 2003 to March 2004 the most unusual occurrence of similar rainfall in both catchments for that period produced an equal amount of flow into the dams even though the catchment areas differed being Upper Brisbane River 5554sq klms to 1503 sq klms. Refer year 2004
However, when major events come west enough to engage the Upper Brisbane catchment, major floods occur. Refer to chart of the three major floods. As one can see, the major floods can be retained above the dams and flows below the dams allowed to quickly pass. 
A common fault not recognized is that 58 per cent of all water that reaches the Brisbane River mouth comes from above the dams. This has been confirmed in writing to me by the Chief Hydrologist Alma Mahmutovic This is an important point when considering flood proofing Brisbane. Others do it by area which is 50% incurring a major variation in their calculations.

(2) Normal rainfall and storms

Having retrieved all the data from the rainfall stations in the Summer V Non Sum Percent.jpg (197951 bytes) catchment of both dams , it is clear since records began that the four months December to March receive over 50% of all rain.  These months are likely to produce some flow but not much, whereas the other eight months produce little or no flow. The 20% deficiency for the 2001-2007 period was entirely in these "low flow/ no flow" months.
Rainfall for the December 2001-March 2007 period was close to 100% of the long term average for both catchments. While there was traces of drought there was no drought in the catchments. Have a look at Rainfall 2001-2006. Somerset catchment - 91.1 per cent of the long term average. Wivenhoe catchment 99.4 per cent of the long term average. The question is "how can this be?" Read on and solve the conundrum.

Storms play only a minor part in our water supply as the storm period Oct2011/Mar2012 shows in the 15 storms recorded. The dam only increased a little over 3 per cent. Have a look at Storm Rains

So the irrefutable facts disclose that not only was there no drought in the catchments, it proves that normal rainfall and storms do not provide sufficient water for our needs and nothing towards recoupment of our dam draw down requirements.

In addition the Ecology comes before us

The Ecology requires 66 percent of all water that passes through the Dams (Confirmed by Minister Robertson many times) and the nodes laid out in the Water Resource (Moreton) Plan 2007 

When one takes into account the Water Resource (Moreton) Plan of 2007 requirement that 66 per cent of all water that passes through the Wivenhoe/Somerset must be allocated to the Ecology of the Brisbane River (I have no problem with that per- centage), then one can see that we have a major shortage of available water.
Have a look at WATER SHARE

It gets worse, when we had confirmed in a meeting with senior DERM officers that the 66 per cent requirement of Technical Advisory Panel was bypassed by them and increased internally to 78 percent. This reduced the yield of this massive piece of infrastructure from 446,900ML annually to 286,000ML with the corruption of a single definition by the stroke of a pen. 

That is the annual output of 3 and 1/2 desalination plants at a capital cost of $4.5 billion. Whereas the restoration of a single definition will restore this output at no cost. To date I have seen it now recognized by management who claim it is not in their area and therefore no progress towards restoration has been made.

We became interested in this calculation as both the hydrology and engineering reports drawn up both declined to cover the pumping between Wivenhoe/Expanded Borumba as they had been advised "that there was no water available from the Wivenhoe/Somerset system". A statement now proved false.

(4) "Uncommon events" being Monsoons, Cyclones, East Coast lows and other major events that cause floods

The major section that does the heavy lifting for our water supply is the "Uncommon events" as described by Mr Drury, Seqwater, (his term and a good one) a little later. They do not come every year and in some periods their absence extends for up to 11 years. See graph down a few lines under "anatomy".
I have retrieved all of the events that fit the "uncommon events" and in the last 160 years there are 101 years that have not received their benefit for longer than 5 years.

(5) The anatomy of "Uncommon events"

As you will see a major piece of the conundrum is provided by Mr Rob Drury, Dam Manager of Seqwater in 2007. He is aware that it needs what he calls "uncommon events" to fill these large dams and that they do not come every year. The evidence backed up by the chart of the Wivenhoe dam levels is irrefutable. Mr Drury was clearly aware that it Summer Rain Courier Mail 10 02 7.jpg (371046 bytes) Wivenhoe dam levels red line.jpg (112485 bytes)took "uncommon events" such as monsoons, cyclones and I wouldLow pressure systems 1841.jpg (116692 bytes) add, full scale East coast lows, to fill our dams. He added that they do not come every year. The chart of the Wivenhoe dam for the years in operation from 1986 to 2006 support Mr Drury's view with an average interval of 3.7 years in what turned out to be good years.

(6) DROUGHT and its confusion with "uncommon events". Mr Drury was right they do not come every year and can stay away for 11 years


On the other hand, the longest drought that we have experienced in South East Qld is the Federation drought 1898 to 1903 being 5 years in length. CLICK to examine. It is this drought that the Queensland Climate Change Centre of Excellence attempted to match the period 2001 to 2009 and failed after having to add at least two years where no drought existed anywhere in Queensland (BOM information).

With a 3.7 year "uncommon event" average in good times in the Wivenhoe Dam, it does not take much variation of the average to push us into periods longer than the federation drought.

Uncommon events

I have taken the time to identify these "uncommon events" since 1840 Low pressure systems 1841.jpg (116692 bytes) by use of all BOM rainfall data in both catchments, flood information from BOM and flood heights at the Port Office having had written advice from the Senior Hydrologist of DERM that 58% of the water that reaches the mouth of the Brisbane River comes from above the dams.

You will  see from my constructed chart that 101 years of the 160 years of records had not received any inflows from " uncommon events" for 5 years or longer. There are two periods of 11 years. 

The most recent period of 2001 to 2007, being 6 to 7 years was added to by the Climate Change Centre of Excellence by a further two years in an attempt to match the dams. However, BOM records had those two years 2008 to 2009 as recording rainfall at 125% of the long term average and not a drought to be seen anywhere in Qld.

When confronted with these facts most defer to a nonsensical term of "Green drought" or a ephemeral "Climate Change" explanation. A possibility in a garden club but not for guardians of our water supply.

Seqwater will have to be careful not to fall into this trap as did their forebears with the term "Millennium drought" most likely used as an excuse for lack of preparation. However we wish to make it clear that this is not a witch-hunt but views put forward to clarify the situation.

(7) Consequences

All this means that under normal rainfall there is not sufficient flow to Dam_levels_Graph.jpg (130699 bytes) provide for our normal consumption nor to raise the water level in the dams to replenish use. For example the storm season of 2011 had 15 storms over the dams that produced a rise in the dam level of just 3 percent. Click to examine.

 Typical reduction without an "Uncommon event". Reduction of 25% at start would have had dams in negative.

This means that we are in a similar position to year 2001. With the dams full or near full how do we provide for completely empty dams for a further time of 6 years being the longest time 11 years less 5 years of a full dam if not interfered with in the method outlined by the Flood Inquiry by dropping the full level to 75% at the start of their wet season. 

The answer lies  in (B).

(C) Seqwater engineers at our recent meeting were anxious that we overcome two aspect that they quite rightly saw as possible impediments to our scheme.

The first was of an ephemeral nature. 

How do we deal with a flood 5 times larger than our largest recorded flood the 1893 at 2,799,234ML above the dams? (The 2011 flood was 418,835ML less than 1893)  It takes little imagination in a flood of that volume to see the demise of Ipswich and most of Brisbane with major loss of life and property. 

Being a matter of untold consequence, I involved the Chairman of Seqwater who provided the answer that while the dam controllers may be required to have the Wivenhoe in that condition to pass a flood that size, it was highly unlikely that such a flood would eventuate and the local governments below the dams provide for known flood heights. Our proposition therefore remains unchanged.

While this point remained unresolved at this meeting there was no prospect that our method of flood-proofing Brisbane and mitigation in Ipswich and Gympie could be discussed with these members of Seqwater until this matter could be resolved within Seqwater. Naturally, from their point of view, the opportunity for discussion was flatly denied.

The second was of a more practical nature. 

Two-way pumping from Wivenhoe/Somerset dams to and from Borumba Dam expanded to 2,000,000ML. A distance of approximately 65klms.

Seqwater representative presented a longitudinal pipeline presentation. He was of the opinion that if the transfer rate was 4,000ML a day then tunnels would have to be bored at the current size of traffic tunnels at a cost of many billions of dollars.

There are two aspects to consider

Engineering model twice presented to the Government of the day

Having twice presented the Government of the day our engineering model, it was a surprise no such conclusion had been reached before. Frankly I was unprepared having dealt with this years before. Our presentations were for 1,000ML a day and can be viewed where it was part of an alternative submission to the Traveston Dam. Click to VIEW.

The key to pumping required volumes was not flood waters. Events in 1893 Floods chart.jpg (106195 bytes) the month of February 1893 show us that while our largest flood height was early in the month, a large flood later in the month piggy-backed a mid range flood in the middle of the month forcing a second flood only centimetres in height from the early flood.

Hence the requirement of the dam controller to release all floods within one week. This is most likely insufficient time to transfer significant volumes to the expanded Borumba Dam.

The waters to be transferred are widely canvassed in Water Share being 160,000ML available annually. It is my observation that private engineers who saw the difficulty of flood water being processed to the expanded Dam were unaware of this deliberate alteration (admitted) in favour of the Ecology over and above the requirement of the Technical Advisory Panel.

It is this volume hat can be pumped over a period of time through 1000ML a day volume at night when electricity rates are low as pumping at less than 1,000ML a day will be required.

This volume can be complemented by flood waters that can be collected in Bor releases 62 to 2002.jpg (296834 bytes)the Borumba dam expanded to 2,000,000ML. These inflows are well above requirements of the Mary Valley. It is flood waters that now overflow that we are interested in. It is my observation that the Borumba has a secondary catchment and Gympie floods are substantially increased by that catchment activity with two floods in recent times 6 metres over the spillway.

Engineering model obtained by the Government of the day to cover water extracted from proposed weirs in the Mary Valley

HWP Eng Line.jpg (51798 bytes)This was originally proposed and later withdrawn by Ron McMah. The terms of reference were completed without reference to Ron who was still corresponding with former Premier Bligh. It suited proponents of the Traveston Dam as it added almost $2 billion to the cost. Supplied in this website is the evidence.

The model was supposed to cover the pipeline from Wivenhoe but they had received "advice" that no water was available for temporary transfer from the Wivenhoe/Somerset system. Hence our meeting at a much later date which gained admission from two senior member of DERM that they had "tweaked" the system the consequence being a diversion of 160,000ML to the ecology not required by the high powered Technical Advisory Panel.

However it gave us a costing of the expansion of the Borumba Dam and design of a pipeline and cost from the other direction which is similar to the model above for 35klms of the 65klms.

Pipeline: On page 29 of their report the costing for the 31klms of that pipeline, which includes the steep rise to the valley, was $349million excluding their acknowledged relative high contingency cost of an additional 50%. As it covers the most difficult section of the terrain, the cost for the balance of 30klms should be significantly lower.

Dam:  The dam to a capacity of 1,650,000ML built in 3 stages t match the Traveston costed at $1,396 million including the 50% contingencies. Deduct that 50% on cost and we have $930 million.

The overall cost is around the cost of one desalination plant.

Management of our water supply

Our current dam managers are in danger of adding themselves to a long list of those deceived by this conundrum. It started with the Climate Change Centre Of Excellence click QCCCE supported by DERM with the so-called "Millennium" drought. It was followed up in more recent times by the Flood Inquiry and its reduction to 75%. Further evidence is the reconstruction of the roads at the same level without raising impeding free releases from The dam.

The matter is further compounded by the deliberate misstatement (admitted) of the allocation to the ecology reducing the yield of the Wivenhoe from 446,900ML a year to 286,000ML. This variation created by manipulation of a single definition is equivalent to the output of 3 1/2 desalination plants of the Tugun size. click Water Share for further information.

The structure of the SEQ Water Strategy, the fate of desalination and lower water costs now rest largely on this calculation.


Seqwater is central to the decision making process of water in South East Qld. Our relations with them have been cordial and constructive.

It is not surprising that both the Flood Inquiry and those in Seqwater that we have spent time with and I suspect most of us who live in South East Qld expect low level dams and "drought" outside the catchments of the Wivenhoe/Somerset dams to match. The Climate Change Centre of Excellence also believed this to be the case and went to extraordinary lengths putting square pegs into round holes (see tab QCCCE). The consequences of this simple statement not being understood have have had a profound effect on our water supply planning costing us billions of dollars with a strong possibility of running out of water of any sort.

On the other hand, the longest drought that we have experienced in South East Qld is the Federation drought 1898 to 1903 being 5 years in length. It is this drought that the Queensland Climate Change Centre of Excellence attempted to match the period 2001 to 2009 and failed after having to add at least two years where no drought existed anywhere in Queensland (BOM information).

With a 3.7 year "uncommon event" average in good times in the Wivenhoe Dam, it does not take much variation of the average to push us into periods longer than the federation drought.

I have taken the time to identify these "uncommon events" since 1840 Low pressure systems 1841.jpg (116692 bytes) by use of all BOM rainfall data in both catchments, flood information from BOM and flood heights at the Port Office having had written advice from the Head Hydrologist of DERM that 58% of the water that reaches the mouth of the Brisbane River comes from above the dams.

You will  see from my constructed chart that 101 years of the 160 years of records had not received any inflows from " uncommon events" for 5 years or longer. There are two periods of 11 years. 

The most recent period of 2001 to 2007, being 6 to 7 years was added to by the Climate Change Centre of Excellence by a further two years in an attempt to match the dams. However, BOM records had those two years 2008 to 2009 as recording rainfall at 125% of the long term average and not a drought to be seen anywhere in Qld.

When confronted with these facts most defer to a nonsensical term of "Green drought" or a "Climate Change" explanation. Seqwater will have to be careful not to fall into this trap as did their forebears with the term "Millennium drought" most likely used as an excuse for lack of preparation. However we wish to make it clear that this is not a witch-hunt but views put forward to clarify the situation.

This means that we are in a similar position to year 2001. With the dams full or near full how do we provide for completely empty dams for a further time of 6 years being the longest time 11 years less 5 years of a full dam if not interfered with in the method outlined by the Flood Inquiry by dropping the full level to 75% at the start of their wet season. 

Premier Beattie's answer was the Traveston Dam, Desalination plant at Depleted Wivenhoe.jpg (264602 bytes) Tugun and recycled effluent. With the cancellation of the Traveston, Premier Bligh left us in no doubt that we would one day be experiencing severe drought restrictions with desalination and recycled water kicking in at 40%. I have to agree with the exception that on occasions it will be severe for many years as matters now stand.

Most of this can be controlled and eliminated by the stroke of a pen and all of it including flood control when one reads "Our future" in (B)

With the advent of the Water Resource (Moreton) plan of 2007 the yield of the Wivenhoe/Somerset was reduced from a Seqwater published yield of 446,900ML annually to an a volume of 285,000ML annually which matches the total of all allocations to users. This reduction of 161,900ML annually is a massive reduction equivalent to the output of 3 1/2 desalination plants of the Tugun size at a capital cost of $4.5 billion plus running costs.

The fault is a mater of arithmetic and not hydrology or engineering. It is further explained at Water share. The two most senior members in DERM admitted to us that they had "tweaked" the system outlined by the Technical Advisory Panel. The "Tweak" from 66% to 78% for the ecology produced the discrepancy by a simple definition. It can be reversed in the same way.

(B) Our future : is here

CLICK ON THE Following


Three days after this was tabled at a meeting with Minister McArdle, the flood of 2013 did exactly as predicted. With sufficient space in the Wivenhoe all water above the dam was withheld (our objective even for the 1893 flood) allowing us to observe the below dam Bremer River and Lockyer Creek in full flood without the blocking confluence normally created by the Wivenhoe/Somerset. 

Brisbane and indeed Ipswich were flood free despite dire warnings from Premier Newman and Lord Mayor Quirk. I believe that it has produced an open mind for this relatively simple procedure. Premier Newman has advised us that if it "stacks up" it will receive greater attention from the Cabinet.

Their future: is Recycled effluent/other waste water and desalination

They would have our future in this direction which leads us back to the past. Ministerial statement (Hon Ed Casey ALP) on cancellation of Wolffdene Dam 1st March 1990

"I have further instructed the Water Resources Commission to investigate new studies into the water needs of South Eastern Queensland and to review all potential alternative sources including storages, ground water, waste water reuse, demand management and desalination"          for FULL STATEMENT Click

This is shaping up to a bungle rivalling the cancelation of the Wolffdene dam and lack of understanding that it is "uncommon events" that fill our dams.

According to Minister McArdle and his Department "Discussion paper : shaping our water future" the discussion on the future leads to recycled water and desalination. Items we thought were not in the LNP policy. Not so, they the main thrust of their future.

In the working section there are no less than six illustrations of these two items that should not exist in a subtropical environment.

Three of these examples are

Page 12, Under the heading "empowering customers" reads "As demand for water increases, sources such as desalinated water recycled water and storm water need to be considered"

Page 15. Queensland water sources readAlthough we have mainly used climate-dependent surface and ground water sources in the past, we need to consider alternative water supplies such as recycled water, stormwater and desalinated water."

Page 14. The graph under the heading “the water cycle” reads “Adapted from recycled water in Australia. It includes “Recycled water plant” and “Desalination plant”

There they are shaping our water future. They are there because former Premier Bligh was correct on the demise of the Traveston Dam, the only storage of consequence attempted. "Look forward to a future of desalination and recycled water plus harsh water restrictions".


In a 30 year water plan there are no other alternatives of a scale to keep pace with rising water needs.

There are no applications that will eliminate flooding in Brisbane and mitigate flooding in Ipswich and Gympie.


The way forward

However, the integration of the Borumba dam expanded to a capacity larger than the joint capacity of the Wivenhoe/Somerset can resolve these matters

At a saving of $3.1 billion, we can flood proof Brisbane (thought impossible by Premier Newman and Lord Mayor Quirk), mitigate flooding in Ipswich with four of the last five floods kept below the damaging 14 metre mark, mitigate flooding in Gympie by damming the Borumba hard rock catchment which is within the Gympie catchment. Provide natural water to pass the much longer catchment periods than drought being 11 years


Progress with Seqwater in the examination of our plan.

On the 13th January 2013 the Courier/Sunday Mail published our plan in simplified form. It may be still held on line at the above link to the Courier Mail.

Even before we started they had this to say

We seek to ensure infrastructure is not augmented before it is needed”. It seems a reasonable methodical approach. It is this approach that got us into big and costly trouble in the past and will do the same in the future if it is not recognized. (Seqwater initial letter) E.G. Prolonged drought known as "uncommon events" and flooding do not lend themselves to this approach in fact in recent times we have seen us damaged by several billion dollars.

This is the demand management instituted by Minister Casey on the cancellation of the Wolfdene Dam in 1990. It screwed up well laid plans for future use by this method by the dam cancellation. Our plan is to reinstall that dam with the expanded Borumba Dam.

They also declined to consider the Borumba expansion for at least another 6 years. Even then they said it would be subject to robust discussion. That dam expanded is central to the natural water needs of SEQ for the next 50 years. 

So we see that even before we have reached the conference table they have laid down their positions which demonstrates to me that they have little grasp of how our water supply works and what additional benefits can accrue or they are reading off prior information. There were many editions of the prior "South East Queensland Water Strategy". This flows through to Minister McArdle and his advisors who draft his letters.

Our understanding at the meeting with Minister McArdle and Seqwater was that our plan would be examined "as it is" to see if it works and then for Seqwater to re-examine their position on integration. They have reversed this procedure with two major blocks exposed as briefly outlined above. The blocks are movable and should be removed.

We hold a reasonable financial hand in the development such as inclusion in the LNP national 100 dam plan. This was the result of our efforts. We have pointed out the error in the allocation of the Wivenhoe/Somerset water at a saving of $210 million annually. The damage caused by a large floods is in the $billions.

Recently they considered a "workshop". We consider that the plan's Hydrology has been proven by events. Engineering of the project requires a one on one with a Government engineer. Then a "workshop" could be of value.


Flood proofing Brisbane proven by the February 2013 flood

The flood of 2013 had important milestones that confirm my calculations below.   Bremer and Lockyer

There was no flooding in Brisbane of any habitable premises (Lord Mayor Quirk).

There was no flooding in Ipswich. Mayor Paul Pisasale.

I seem to be the only one that was not surprised by the outcome.

The Wivenhoe Dam had sufficient room to hold back all water above the dam and as a consequence, we saw the effect of a full blown Bremer River and Lockyer Creek running free. 

It is the foundation of this website, when viewing flooding, that the Bremer River and Lockyer Creek, on past information, does not have the volume to flood Brisbane and damage Ipswich. In Ipswich, most of the block caused by the Wivenhoe at the Bremer entrance is removed.

Move to review  Bremer and Lockyer


* To move direct to Flood Proofing Brisbane. Mitigation in Ipswich and Gympie. CLICK HERE
To move direct to Drought Proofing South East Queensland
To view the Borumba Dam expansion, an integral part. CLICK HERE to view channel 10 review of Borumba Dam

A brief overview of our water supply

Natural water

Since the completion of the Wivenhoe Dam in 1986, in the period 1986 to 2001 we  Wivenhoe dam levels red line.jpg (112485 bytes)witnessed the dam filling by 1988 and a further 4 refills in 1992, 1996, 1999 and a top-up in 2000. It takes "low pressure systems" to do this as recognized in this graph by its "factory roof type" in its dam levels. In that 12 years, we had plenty of water or so we thought.

In the second 12 years 2001 to 2012 we witnessed a "drought" or so we thought and followed by the flood of January 2011. The flood was no surprise to me having observed the operations of nature and the dams to the point that I backed my observations up by warnings to Premier Bligh and Minister Hinchliffe in 2008 and 2009.
Read more

Manufactured water

Desalination : The Tugun plant would take 26 years to 2038 to fill the Wivenhoe dam if no water is taken out. 35 years to year 2047 if the Somerset is included.

Recycled water : Using reports of former Premier Bligh, recycled water is the same volume.

Between them they can only supply 31 per cent of our present requirements. This means very heavy water restrictions on reaching 40% level in our dams.

Much better way

Much better way: There is a much better way to eliminate flooding in Brisbane, mitigate flooding in Ipswich and Gympie, put real meaning into "drought" proofing Brisbane and reduce water price permanently. That is what this website is all about.

So we have seen it all in a practical way in our lifetime. However we have not learnt from this and the LNP appears to be following the same path. 

Residents of South East Queensland deserve better than a second clumsy go at securing our water supply which will be again at a high cost.

Post Election/Flood Inquiry - period

With election out of the way and the final flood report tabled there are some clear issues emerging.

1. Our Wivenhoe/Somerset dams are too small to deal with the conundrum of "Drought" and "Flood".
2. The Flood Inquiry was blocked from examining new dams or the expansion of existing dams on page 438 of its report.
3. This coordinated with the version of the South East Queensland Water Strategy that relied solely on desalination and recycled water after the Traveston dam proposal was cancelled.
4. There was overwhelming support in submissions to expand the dams.
5. The LNP is averse to using desalination and recycled water. (this was their position before the election. It has to be clarified by the LNP as this may not be their current position).
6. There are two options to increase the capacity of the dams. Raise the Wivenhoe Dam wall or expand the Borumba Dam to a capacity greater than the Wivenhoe/Somerset and integrate it into the Wivenhoe/Somerset system by way of efficient two-way pipeline.
7. The cost of water is substantially reduced by either proposal, however the Borumba has the ability to more than double the water available and as a consequence greater flexibility in both drought and flood.

The current block to the system (point 6) that needs to be rectified. Points 8 to 13 cover point 6 Click hereto view these points

We cannot go forward unless we assess what went wrong in the past.

* What went wrong with our water supply?
* Serious errors of judgment of those in charge
Click for index

* Flood proofing Brisbane and Ipswich and mitigating flooding in Gympie. Providing a superior and less costly water supply than desalination and recycled water and putting real meaning into "drought proofing" SEQ.

Click for full index


What went wrong with our water supply?

What went wrong with our water supply that caused those in charge to miss-spend the best part of 7,000 million dollars for a third class system that will not do the job intended? 

How could we not foresee from past experience the inevitability of extended "drought" like periods and  major floods in South East Queensland?

Depleted Wivenhoe.jpg (264602 bytes)Premier Beattie sitting on a stump in the depleted Wivenhoe Dam. (Click to expand)

He failed to realise what was happening around him was something other than a "drought" with consequences that can be much more severe than any drought. The natural and random occurrence of our main water supply has such a variation from top to bottom that on the opposite end it would have had Premier Beattie sitting in a small boat in the Jindalee area or other parts of flooded Brisbane five years later. 

The bottom end is limited by the capacity of our dams whereas the top end is unlimited. A volume equivalent to two and one-half times the capacity of the Wivenhoe went over the dam wall in January 2011. We examine the random and extensive nature of our main water supply events in the next heading.

His successor Premier Bligh also displayed this lack of understanding. I warned her of it on the 18th January 2008 followed by a warning to then Water Minister Hinchliffe on the 23rd April 2009. The warning was the mathematical certainty that our dams would refill and overflow. Read more

Our water supply

Wivenhoe dam levels red line.jpg (112485 bytes)Every person in South East Queensland now realises that our dams are not filled  by storms that provided only 3% in the last 6 months and not by General rain which provides only moderate fills, the largest in the life of the Wivenhoe being 15.6% in the middle of so-called drought. One can see the small bump in 2003/04 on this dam level chart. Read more
SEQWater dam level chart 1990-2007 : click to expand 

The red lines on this dam level chart emphasise the clear statement of Mr Rob Summer Rain Courier Mail 10 02 7.jpg (371046 bytes) Drury, dam controller, of SEQWater who pointed out in his article in the Courier mail Feb 2007 that it took large events to fill these large dams. He called them "uncommon events". It confirms Dorothea McKellar's OBE poem of the early nineteen hundreds that there is a big difference between "rain" and "flooding rain". They show two things:
SEQWater Courier Mail article Feb 2007: Click to expand

Low pressure systems 1841.jpg (116692 bytes)1. Ordinary summer rainfall and storms were inadequate for our needs from the starting point of the Wivenhoe Dam. It takes concentrated rain ("flooding rain") as 300mm in a few days is a flood capable of filling the dams from scratch whereas 3 months of 100m each month is just a trickle.

2. The "uncommon events do not come every year". They average 3.7 years with most below that average. This means that those above the average can extend for up to 11 years which is well beyond the longest known drought being the 5 year Federation drought 1898 to 1903. They are more prevalent than the chart indicates as many do not come west enough to cover the catchments. 

The volumes that are supplied by "uncommon events" vary from 20% to 285%. We have now all seen four of these "uncommon events" refill the dams from 18%. Overflows then occurred with 26% in October 2011 followed by December with 24% and finally January with overflow of 285%.
Combination of flood heights, Bureau flood information and rainfall. Click to expand picture.


Review of serious errors of judgment will give us further insight on how to deal with Flooding and putting real meaning into "drought proofing". This is not a political statement. It should be kept in mind that the dams were under the control of the Labor Party for the  life of the Wivenhoe (1989-2012) of 23 years except for three years. 

Serious errors of judgment

1. Kevin Rudd - Wolffdene Dam
2. Premier Beattie and Deputy A. Bligh's "drought".
3. Premier Beattie and Deputy A. Bligh. - The Traveston dam
4. 1992 to 2001 Those in charge and the Flood Commission.
5. Queensland Climate Change Centre of Excellence
Return to Index foreword

Kevin Rudd - Wolffdene Dam

Wolffdene dam water supply

Wolfdene_dam_drips.jpg (272794 bytes)The initial error of judgment was made by the Goss Government with his chief of staff Kevin Rudd. It was supported by the "rump" Liberal party and was plainly put forward in the Goss election plank.

By 1992 it was obvious from the dam level chart of the Wivenhoe Wivenhoe dam levels red line.jpg (112485 bytes) pictured on our right that our water supply could not survive without "uncommon events". Assurances were given at the time of cancellation (Planning had commenced) that further planning would be carried out. If planning was carried out it was entirely inadequate for "drought" and "flood". Read official parliamentary statement

Wolffdene dam in flood time

This 2011 flood saw all catchments saturated. There is no doubt that the Wolffdene dam would have been full well before the January 2011 flood. This would have permitted the pre-release of water from the Wivenhoe/Somerset sufficient to retain all the flood waters of the Wivenhoe/Somerset. With the Bremer River and Lockyer creek running free, there would have been little damage in Brisbane and Ipswich.


Premier Beattie and Deputy A. Bligh's "drought".

Brochure.jpg (257138 bytes)Premier Beattie used the "decile" map extensively to convince us that our low dam levels were caused by a "drought". Decile maps grade rainfall from 1 to 10 with "1" the "lowest on record" category. The corresponding map is a "percentage" map that records the percentage against the long term average 1961 to 1990.

The rainfall for the period was in decile "1" even though the rainfall was 80% of the long term average. This is because district 40 in which the dams reside is a stable area and in 6 year lots, (the length of the so-called drought) never had less than 80% of the long term average since records were kept. So we are dealing with a statistical aberration. 80% being in decile "1" was not normal but was held out by Beattie/Bligh to be normal and accompanied by an enormous advertising campaign to convince citizens of SEQ of drought in the catchments.

Bureau of Meteorology rainfall stations in the catchments show that for the summer periods 2001 to 2006, Wivenhoe had 99.1% of the long term average and Somerset 91.4%. The 20% reduction was entirely in the non-summer months that produce little inflow into the dams. 

If Premier Bettie had held the "percentage" map aloft which read 80%, then people would have considered the matter more deeply and required more explanation and perhaps the right path forward.

Read more

Premier Beattie and Deputy A. Bligh. - The Traveston dam

For citizens of South East Queensland, the choice of the Traveston over an expanded Borumba Dam to a holding capacity more than the Wivenhoe/Somerset combined was a monumental and costly blunder.

The public guarantee of Ms Bligh to residents of Gympie dealing with the Borumba that Bligh  Ron McMah 1.jpg (47253 bytes)Bligh  Ron McMah 2.jpg (28777 bytes) "that would be the way they would go if it stacked Traveston 110000 Beattie.jpg (225087 bytes) up" was a sham. Ms Bligh was writing to grazier Ron McMah to obtain commonality of the terms of reference so that the Engineering and Hydrology reports could start. Those reports had been

completed on Queensland Water Commission (QWC) terms and signed off a week prior to her letter.

Letter Bligh 31/01/07 : Signed Engineering 22/01/07 : Beattie view ignored by Bligh

The most important feature of the McMah proposal was the storage of surplus water from the Wivenhoe/Somerset. The catchment of the Borumba was too small for for such a large dam and we needed more capacity. 

Both the Engineers and Hydrologists reported that they had received "advice" that there was no water available from the Wivenhoe/Somerset. After meetings with Minister Hinchliffe and later senior members of DERM, I was provided by the Chief Hydrologist the information necessary to determine that there was available between 130,000ML and 160,000ML annually to us that had been diverted to the ecology by a clever, or alternatively clumsy, manipulation of a single definition. The instructions of the Technical Advisory Panel had not been followed 

It explained to me why the "yield" of 446,900ML as publically advised by the Yields_Annual_SEQWater_web.jpg (114473 bytes) former SEQWater, not connected to the current Seqwater, being reduced to 286,000ML, a drop of 160,000ML. (Yield is the volume of water that can be guaranteed in a year without failure otherwise known as HYNF)
Annual "yield" in public documents of SEQWater 2001. Click

This volume of 160,000ML plus the additional yield from the expanded Borumba of a further 50,000ML is well above the 110,000ML Traveston proposed by Premier Beattie with the final stage of 40,000ML well into the future and ephemeral.

With the Traveston cancelled by the cross-check environmental concerns of the Federal Government that were not picked up by the QWC and the contractors, Premier Bligh declared that "desalination" was the only answer.

That decision was seriously deficient and we will examine. 

Read more

1992 to 2001 Those in charge and the Flood Commission.

There was no panic or serious observation of how our water supply works in that period. However there is cause for concern when we apply their findings on dam reductions to counter flooding. 

The Wivenhoe and Somerset dams were designed with flood compartments that exceed the FSL (drinking water compartments). The Commission recommends manipulation of these FSL volumes for flood mitigation benefit.

Application of the current 25% reduction in November 1995 would have seen the dam level fall to 19.7% (44.7 - 25.0) That level is comparable with the so-called "drought" period low in 2007 of 18.0%. Application of the 25% in that period would have seen a negative figure of -7.0%.  

The dam controllers do not have the ability to allow the dam level to rise. They have to await a "low pressure" system to come along. They average 3.7 years since 1841. The dam level graph above tells the story.

There is currently not enough capacity in the dams to deal with this conundrum.

Queensland Climate Change Centre of Excellence

QCCCE_page_1.jpg (68511 bytes)In my view this organisation has presented misleading information in the name of "Climate Change". They produced this document that has been picked up in the Queensland Water Commission Water Strategy and now by  the Flood Inquiry in its interim report. There are fundamental major errors in it and it should be withdrawn.

They may be viewed in QCCCE

A review of carbon dioxide tax can also be viewed click here

One example of predictions is by well known Mr Tim Flannery now chairman of the Federal Government Climate Change organisation. He was on the original Board of the QCCCE in 2007. As reported in the "Herald Sun" "In 2007, Flannery predicted cities such as Brisbane would never again have dam-filling rains, as global warming had caused "a 20 percent decrease in rainfall in some areas" etc." 

The Herald goes on to say that premier Beattie took the prediction seriously leading to desalination.

The prediction was badly astray with serious consequences. Since 2007 the Major dams of Wivenhoe/Somerset not only filled to 100% capacity by March 2009, well before the La Nina weather pattern took hold, and then overfilled with the volume well above twice the Wivehoe Dam capacity going over the dam wall by January 2011.

In their scramble for authenticity they added a further two years to the "drought" being years 2008 and 2009. You will see the evidence that in those two years the catchments had rainfall of 125% of the long term average.

The QCCCE therefore had a two-pronged excuse for low dams of "drought" and "Climate change". Because these excuses were accepted, research into the underlying cause of depleted dams was blocked and, as a consequence, contributed to considerable damage from flooding in Brisbane and Ipswich. 

It was also consequential in producing a water grid costing billions of dollars that is largely ineffectual.

Viewed in QCCCE

Return to Index foreword

Flood Proofing start

Flood proofing Brisbane  
from damaging floods to the point of extinction
Mitigating flooding in Ipswich and Gympie


Full index

Flood proofing

* Borumba dam integration. Where is it and what does it look like.   Click to go direct
* Overflows lost to our water supply  
Click to go direct
* Flows above and below the dams   
Click to go direct
* Flood volumes   
Click to go direct
1. Overview
2. Reported flood volumes
How has the Wivenhoe Dam performed since installation in 1985?
Review of Bremer River and Lockyer Creek
  5. Logic of flood mitigation in Brisbane
  6. Flood mitigation in Gympie
  7. 1841 and prior
  8. The largest flood to contain


* How to deal with major floods  
Click to go direct
1. Saturation rain  
  2. Flood compartments available  
  3. FSL or commonly known as “drinking water” compartments  
  4. Total capacity to retain floods if all the compartments are available.  
How does this work?  
  6. How do you cover your gamble if it does not pay off?  


* Borumba dam integration the answer 
Click to go direct

Drought proofing Click to go direct
1. Another look at our so-called "drought". These drought like breaks     in our water supply are more severe than any hydrological drought.

Water share between the Ecology and residents of South East Qld. Click to go direct

Return to Foreword


Borumba Dam integration with Wivenhoe/Somerset: Where is it and what does it look like

This involves the integration of the Borumba Dam 40 Klm over the hill from the Moreton resources.jpg (141612 bytes)Somerset dam with the Wivenhoe/Somerset Dams. It has the dual purpose of backup supply enabling the Wivenhoe Dam to be permanently lowered and further lowered to be almost empty before a major flood. With two-way pumps capable of transfer rates 32 times the output of the Tugun desalination plant, normal water supply will be available during any "drought" period.

Click to view the location of the dam

This is the low cost expanded Borumba Dam to 2,000,000ML for Top of ridge look at dam TH.JPG (353942 bytes)Borumba Dam now.jpg (698155 bytes) storage and later return to the Wivenhoe/Somerset system. The cost for the Dam expansion, hydro plant, pipes and pumping equipment has been costed by engineers at no more than the Tugun Desalination plant.
Click to view the current dam and view from the ridge

CLICK HERE to view channel 10's review of this Dam. It includes an interview with local grazier Ron McMah. Trevor Herse, retired of the Gold Coast and myself were well aware of the huge water surpluses of the Wivenhoe/Somerset catchments from "low pressure systems". We coordinated with Ron who had identified the storage capacity for these surpluses in putting forward this proposal. 

One will notice that the topography of the Dam with high hard rock walls makes it suitable to expand to a capacity larger than the Wivehoe/Somerset Dams as certified by engineers.

Return flood proofing index

Overflows lost to our water supply

With the figures now confirmed a volume of water equivalent to 229.5 percent of the capacity flowed over the dam wall in January 2011. This is in addition to the 55.5 percent that had been released in October 2010 to December 2010. That total of 285.0 percent was lost without a Megalitre being saved.

It gets worse, 25% of the Wivenhoe has now being released.  This means that during the recent events we are 25% of the Wivenhoe capacity worse off than when it started.

The dams began filling in 2007 and have been full since March 2010. This date is well before the La Nina weather pattern took hold. 

There was no reserve supply sufficient to permit early release of our FSL “drinking water” compartment to avoid damaging flooding. That water is regained at the back end of the flood.

Return flood proofing index

Flows above and below the dams

Those who who would have believe that 50% of flood water comes from below the dams are badly astray. They rely on catchment areas without the application of rainfall statistics. 

According to the Water Resource (Moreton) Plan 2007 by their official IQQM computer model, the Wivenhoe/Somerset provides 56.5% of all water that reaches the mouth of the Brisbane River. 58.0% below Mt Crosby. 56.5%  means that water above the dams was 30% more in volume than below the dams. In this 2011 flood, based on evidence presented to the Flood Inquiry, it was 65% above the dams. Again that converts to 85% more in volume than below the dams. 

The temporary retention of "above dam" flood waters clears the way for the Bremer River, Lockyer Creek and the Brisbane River itself to run free minimising impact to just 42 percent of the entire flood. In the case of the 2011 flood it would have been reduced to just 35% of the flood.

This set of numbers following was published by Engineers GHD in December 2011. It was based on Seqwater Historical Flood Events Hydrographs. The 1893a flood had only 23.82 percent of the flood below the dams coming from the main tributaries. Similarly the 2011 flood had only 34.94 per cent below the dam. I have placed the 1974 above dam total in red and I refer to my official supporting information. It indicated the 1974 above dam flood is 2,200,000ML based on official supporting documents. This reduces the below dam percentage to 42.0 percent.

Nevertheless the GHD figures supplied by Seqwater indicate that the 2011 flood had a volume above the dams of 138% more than the 1974 flood. This is a major departure from Seqwater claim of 190% in their much criticised document lodged with the Flood Inquiry.

When viewed with the the 50% catchment area above, it does not give one confidence in the rest of the document.

Above and below dam volumes

Return flood proofing index

Flood volumes  

1. Overview
2. Reported flood volumes
3. How has the Wivenhoe Dam performed since installation in 1985?
Review of Bremer River and Lockyer Creek
5. Logic of flood mitigation in Brisbane
6. Flood mitigation in Gympie
7. 1841 and prior
8. The largest flood to contain


The essential element to flood proofing Brisbane is to know the inflows that occurred since records were kept from 1890 to 2010. This is to determine the flood with the largest inflow volume in the Wivenhoe/Somerset catchments. It is that flood that we must contain.

If we are successful in retaining the largest recorded flood then 58% of the entire flood is taken out of the equation and released without harm at the back end of the flood. It is the peak that does the damage. The 58% is calculated by the IQQM computer model that has the force of Law in calculating the 66% required for the Ecology.

This permits the remainder of 42% being the Bremer River, Lockyer Creek and the Brisbane River’s own contribution to run free avoiding the backwater and barrier created by the Wivenhoe/Somerset outflow.

Reported flood volumes

Seqwater and Brisbane City Council reports have similar volumes and obviously are reading from the same gauges.

The reported flood volumes are:
2011  2,650,000ML ( revision GHD report Dec 2011 : 2,380,396ML)
1974  1,410,000ML ( revision GHD report Dec 2011 : 1,724,841ML)
1893  2,744,000ML ( revision GHD report Dec 2011 : 2,799,234ML)

If accepted, then 1893 at 2,744,000ML is the largest flood that we have to deal with and nothing further needs to be examined. We will see that this volume is capable of being withheld with room to spare. ( GHD report of December 2011 records it at 2,799,234ML)

My review of flood volumes can be examined in the Flood Review tab.

The review suggests to me that a volume of 3,000,000ML will cover all contingencies.

If further examination is sought click FLOOD VOLUMES

How has the Wivenhoe Dam performed since installation in 1985?

The floods of note are 1999 and 2011.

The 2011 flood is under close scrutiny of the Flood commission. The decisions made at flood time are most likely to subject to legal challenge well into the future.

The 1999 flood was on normal and not saturated catchments. The Wivenhoe was at 74.5% of capacity at the start and 135.1% at the end. The Somerset was 44.6% of capacity at the start and 154.2% at the end.

Seqwater placed the flood volume at 1,220,000ML or about 51% of the revised volume for 2011 of 2,380,396ML. That volume for 2011 included 540,000ML for a small flood not fully released early which is the nub of legal argument.

Review of Bremer River and Lockyer Creek

The submission lodged by the Ipswich Council provided some some insight into how floods affect that City. Three of those points are:

1. Damage begins to occur once the flood height at the railway bridge reaches 14 metres.
2. The flood waters of the Lockyer and Wivenhoe/Somerset create a barrier for the Bremer River.
3. Backwater occurs in creeks at or below the Bremer River mouth.

There were 4 floods in recorded history that passed the 14 metre mark. They were 1893 Feb 24.5m; 1974 Jan 20.7m; 2011 Jan 19.25m and 1931 Feb 15.47m.

Bremer 1934.jpg (131102 bytes)Bremer 1893 1974 2011.jpg (151525 bytes)GHD figures are enlightening when reassembled to see the pressure that the Lockyer Creek and Wivenhoe/Somerset catchment place on the Bremer River.

Lockyer Creek produced more volume of water than the Bremer River in all floods.

An example of the pressure of backwater is in 1974 the Bremer flow was 631,195ML whereas the 1893 flood had a flow of 196,825ML which is less than 1/3 of the 1974 flow. Yet the Bremer River Height was 24.50m in 1893 compared to 20.70m in 1974.

Above left are the Seqwater flows 1893, 1974, 2011    Right picture is 1931 rainfall

The hydrological analysis of Ipswich in the 2011 flood had the one mile bridge at 6 metres above due to backwater. 

On that basis, the 1893 and 2011 floods would have been kept below the damaging 14 metre mark.

However, the 1974 flood at 20.70m had to reduce by 6.70m to avoid damage. The rainfall and resulting flows were much higher than ever experienced. My Ipswich correspondents, having experienced the flood, say that may not be the case. Hydrological and hydraulics reports will be necessary.   

Review of the 1931 rainfall is enclosed. Withholding of the Wivenhoe/Somerset will reduce it from 19.25m to below the 14.00m mark.


Logic of flood mitigation in Brisbane


* The highest flood volumes from the Wivenhoe/Somerset is 1893 which this website explains can be contained until after the flood.

* There is a caveat on the 1974 flows for the Wivenhoe/Somerset as the pre-development flows of DERM and the rainfall stations information both conflict with Seqwater volumes. The indications are that the percentage above the dams is in line with the DERM information of 58% average above Mt Crosby over 110 years.

* With the Wivenhoe/Somerset held, the waters of the Lockyer and Bremer run free.

* We know that the 1893, 1913, 1974 and 2011 floods should be below the damaging 14 metre mark in Ipswich with a caveat on 1974.

* A similar pattern should show up in Brisbane.

Flood mitigation in Gympie

The Borumba Dam stands on Yabba Creek. It is researched throughout this website as it was the subject of our submission to replace the proposed Traveston dam. 

My calculations for the 1999 flood is that Yabba Creek provided 34.8% of the total flow through Gympie. To review click on Hydrology Mary Valley

As we will see later on this page, the major part of this proposal is the expansion of that dam from the current 45,000ML to 2,000,000ML. It will provide ample opportunity to mitigate flooding in Gympie to the extent of 34.8% of the flood.

Gympie Yabba Creek.jpg (20187 bytes)


Yabba Creek in full flood 2011(Gympie times photo)

1841 and prior  

  The Queensland Parliament at the time of the 1893 floods recorded that the 1841 flood was 7 inches (.2 of a metre) above the 1893(1) flood. The archaeological find at Indooroopilly, being up river, may well come in under the 1893(1) flood because up river heights are much higher.


For those who appreciate an easier read than the language of this accountant, click on Trevor Herse for his "Water woes result from misunderstanding and blunders". Trevor and I, together with Ron McMah, grazier, of Imbil, have worked together on this project since 2006. We represent no one and have in mind only the interests of citizens of South East Qld.  

The containment of a flood to 3,000,000ML is the target. 

Return flood proofing index

How to deal with major floods  

1. Saturation rain  
2. Flood compartments available  
3. FSL or commonly known as “drinking water” compartments  
4. Total capacity to retain floods if all the compartments are available.  
How does this work?  
6. How do you cover your gamble if it does not pay off?  

Saturation rain

Saturation rain preceded all of the floods under review. It is certain that the FSL “drinking water” compartments were, or would have been, full.

Flood compartments available

The official flood compartment volumes are Wivenhoe 1,450,000ML and Dam_features_from_SEQWater_Web.jpg (215540 bytes) Somerset 524,000ML for a total of 1,974,000. This represents 170 % as a percentage of the Wivenhoe capacity for easy measurement. Mr Ian Chalmers, the chief supervising engineer in the construction of the Wivenhoe has suggested in his submission the relocation of the fuse plugs to maintain these volumes.

FSL or commonly known as “drinking water” compartments

These compartments are not normally reduced as the metrological events that fill them come on average every 3.7 years. Their fill usually represents 95% of the water in the dams.

Click to view official dam statistics Wivenhoe/Somerset

These compartments measure Wivenhoe 1,165,000ML and Somerset 380,000ML. The total is 1,545,000ML. This total represents 132 per cent of the Wivenhoe capacity.

Total capacity to retain floods if all the compartments are available.

The flood compartments total 1,974,000ML or 170 %. The FSL or “drinking water” compartments total 1,545,000ML or 132%. The combination is 3,519,000ML or 302%.

The largest flood of 3,000,000ML represents 258% of the Wivenhoe Dam FSL. This can be held by the flood compartments of 1,974,000 plus the FSL of the wivenhoe at 1,165,000ML which totals 3,139,000ML or 270% of the Wivenhoe capacity. The Somerset FSL is not needed.

How does this work?

There is always the quandary “will flooding rains come or will they not?” 

Our weather forecaster are becoming more reliable in predicting CM 1 10 2010.jpg (134694 bytes)major events in our weather patterns. This article written by Brian Williams of the Courier appeared in their paper on the 1st October 2010. He points out that all dams are full and the weather patterns that produce flooding rains were entrenched. I have observed that throughout the flood period Brian Williams was accurate in reporting all events of the flood and that his reports could be relied upon.

It is necessary to early release the FSL “drinking water” compartments with the recent Bligh/Robertson decision in progress (28/02/11). As events unfold and the flood is reasonably certain, further releases from these compartments should be made at the front of the flood thus allowing the Bremer River, Lockyer Creek and the Brisbane River to run free. 

This avoids the backwater and congestion of the Wivenhoe/Somerset releases. The extent of the early release will depend on the Meteorologists and their telemetry equipment. 

It is a considered gamble on weather predictions.

If the rains do not come then you lose heavily as you have released your precious drinking water with almost no chance of recovery until the next “uncommon event”.

If the flooding rains come, you win well. Not only have you assisted in reducing damaging flood levels by taking the water from the Wivenhoe/Somerset out of play but most, if not all of the water released, can be recovered at the back of the flood.

How do you cover your gamble if it does not pay off?

This is an example of a feeble attempt but a step in the right direction

Minister Robertson supported by Premier Bligh made the decision to release 25% of the capacity of the Wivenhoe dam’s “drinking water”. The backup explained by the Premier was the Wyaralong Dam which represents 6% of the Wivenhoe capacity.

The additional backup is the Tugun desalination plant and the recycled water that a lot of people dislike. The Tugun plant takes 34 years to fill the Wivenhoe/Somerset dams from scratch if we do not take water out. The recycled water takes a bit longer.

The consequence is that we will be out of water in 3 to 4 years Wivenhoe dam levels red line.jpg (112485 bytes) if an “uncommon event” does not appear in the normal average of 3.7 years. It is a very high price to pay for such a small gamble on the weather. The Wivenhoe dam level chart with red lines shows that we rely almost entirely on "uncommon events" to refill our dams.

Click to view "uncommon events" in the Wivenhoe dam 1988-2007

When one exceeded the average in 2001-2007 it was misrepresented as a "drought".

Return flood proofing index

Borumba Dam -The obvious major reserve supply

The reserve supply needs to be in place permanently. The decision making process on release will depend on the concentration of the rain and will determine how much is released without the flood event happening.

It is most likely that no more than 60% of the Wivenhoe capacity would be released without the flood event occurring. This volume is 700,000ML. It is stored for later return if needed by the Wivenhoe/Somerset system.

A proposal to maintain a significant percentage permanently in the Borumba Dam and have a corresponding permanent reduction of the FSL- "our drinking water" has merit. It will give the dam operators more flexibility to early release.

This is well within the storage capacity of the Borumba Dam expanded to 2,000,000ML. This capacity is larger than the Wivenhoe/Somerset dams total capacity.

Borumba Dam - a brief resume

The dam already exists

It is a hard rock natural amphitheatre ideal for minimal evaporation.

Has its own small but efficient catchment.

We own all the land and no disruption to people of the Mary Valley .

It is 60klm over the hill in the Mary Valley. 

The Queensland Water Commission has expansion to 350,000ML in the SEQ Water Strategy

Engineers say it can be expanded to 2,000,000ML or larger than the Wivenhoe/Somerset dams.

1,500,000 for storage and 500,000ML for the Mary Valley

Partial flooding of Gympie avoided. Yabba Creek on which it stands provides 34% of flood water to the Mary River. 

Regeneration of the Mary Valley from its damaged state which resulted from the scrapping of the Traveston Dam proposal.

The costing by engineers of the dam wall is $1.4 billion including the Hydro plant. Engineering view is that the pipes and pumping equipment are in the region of $0.5 billion. Deduct the QWC proposed dam of 350,000ML and we arrive at a cost about the same as the Tugun Desalination plant. 

This compares with the Insurance Council of Australia assessment in 2007 that a 1974 type flood "represents a potential insurance loss of $1.8 billion and a simply staggering loss for both Government and the affected community"

Borumba Dam proposal and appendix on cancellation of Traveston Dam

The Traveston is now historical but the alert to Minister Hinchcliffe and the use of the Borumba Dam as its replacement is still valid. These two proposal and appendix were submitted to the Queensland Water Commission when they were called for after the cancellation of the Traveston Dam. This procedure eliminates the planned three desalination plants and avoids most of the construction and ongoing costs. Further reading Borumba Dam Proposal and Borumba Dam Appendix


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Drought proofing start

Drought proofing SEQ.

1. Drought in the catchments. Conclusive proof that it did not exist.
2. Different approach to "drought proofing".


1. Drought in the catchments. Conclusive proof that there was no hydrological drought in the catchments

Former Premier Beattie, Premier Bligh and now Minister Robertson claim that South East Queensland is "drought proofed".

This section provides a different view suggesting that this phrase is misused to justify an expense in the region of $9 billion according to Mr Kim Wood CEO of Allconnex water (Refer WATER COST). An expensive cost brought about by those who should have displayed more diligence in the control of our water supplies.

This phrase "drought proofing" belongs with the "worst drought in 100 years" when related to the low levels of water in our dams. The evidence presented in this section is that while there was drought in most parts of the State, there was no drought in the catchments.

I have overlaid the Wivenhoe dam level graph with "uncommon events" as described by Mr Drury of SEQWater in the header above. The dam decline from each refill is marked in red. 

That decline was obvious soon after the Wolffdene dam was Wivenhoe dam levels red line.jpg (112485 bytes)cancelled for political reason in 1989. By 1992 it was obvious that normal "summer rain" was inadequate for our needs and we relied heavily on these "uncommon events". A longer period beyond their 3.7 year average would, and did, bring us grief with no provision by those in charge. 

Click to view "uncommon events" in the Wivenhoe Dam 1988-2007

A convenient statistical aberration of a "decile" map was used to avoid scrutiny. The "decile" map was showing "lowest on record" for the rainfall, while the corresponding "percentage" map read 80% of the long term average. This can be viewed at DECISION MAKERS

The Bureau of Meteorology rainfall stations in the catchments were at the same time showing 99.1% for the Wivenhoe and 91.4% for the Somerset for summer rainfall December to March. Viewed at the bottom of the RAINFALL DEFICIENCY page.

A further example of timing of "uncommon events" is this comparison. With a time period of 3 years and 9 months, the February 1992  to Drought V No drought.jpg (52821 bytes) November 1995 was right on average of 3.7 years. The dam level dropped from 100% to 44.3%. Bureau of Meteorology maps show that there was no drought in that period with rainfall 90% to 100% of the long term average. Click to view comparison

Comparing the same 3 years and 9 months period of the "drought" February 2001 to November 2004, the level dropped from 100% to 53.4%. We held 9.1% more in reserve than in a period with no drought.

It is now certain that there was no drought in the catchments Wivenhoe dam levels red line.jpg (112485 bytes) for the 2001 to 2007 period. It was simply the operation of low pressure systems. The 2001/07 period was an object lesson in how the 3.7 average works. Most are below that average so the few that are above can be quite lengthy. 

More recently there have been attempts to extend the "drought" to years 2008 and 2009. I have forwarded to the Qld Flood Inquiry the Bureau of Meteorology Rainfall graphs for those years which show the rainfall in the catchments 125% of the long term average. 

Premier Bligh and Minister Hinchcliffe were warned of this mathematical certainty that Low Pressure Systems would return and overfill our dams.. Click to move to these warnings.

The importance of this is that forward planning by the Queensland Water Commission in its strategy for SEQ is related to preparing for a "drought". 

Our main water supply is low pressure systems. They are random and can occur at any time of the year and for much longer than any "drought". They are oblivious to the conditions prevailing at the time.

2. It requires a different approach to drought proofing.

It requires a different approach from the present stance of "drought proofing" SEQ. 

The current claim of "drought proofing SEQ" is in the same category as "worst drought in 100 years". They both do not stand up to scrutiny by a long way.

The current "drought proofing" relies on the Desalination plant at Tugun which can produce 45,000ML a year. The recycled water produces almost the same based on Premier Bligh's most recent comments.

Seqwater spokesman advised that the current release of 25% was one year's "drinking water". That is 291,000ML a year. The official "allocations" made from the Wivenhoe/Somerset dams are 286,000ML so the spokesman is near the mark. Deduct the 90,000ML from Desalination and recycled water and we have a shortfall of 200,000ML each year for the length of the "drought".

On the other hand the two-way pumps between the Wivenhoe and Borumba Dams can have transfer rates of up to 4,000ML per day compared to using the expanded Borumba Dam storage of the Wivenhoe/Somerset water for later return  

The objective is to maintain the wivenhoe/Somerset dams above 40% level before recycled water is introduced. This is on Low dam levels 1890 2000.jpg (57248 bytes) the basis of a yield of 373,000ML which is considerably higher than the 286,000ML presently allocated. 
Click to view the simulated levels in the Wivenhoe Dam for the last 100 years

On the past history of 120 years, it would require no more than 500,000ML to be retrieved from the Borumba Dam for a period of three to four years at the bottom of the drought cycle. It would have happened only twice in those 120 years.

Pumping to the expanded Borumba Dam would be undertaken when dam levels are high creating space in the Wivenhoe/Somerset dams to capture as much as half of the 55.5 per cent overflow created in October/December 2010.

Engineers have costed the dam wall to $1,397 million. It includes a hydro plant. Add to that an engineers estimate for the pipes and pumps of $500 million and deduct the unknown cost of the Water Commission dam wall to 350,000ML and we have a cost equivalent of one desalination plant of the Tugun size.  

Compared to the high cost desalination, the operating costs are minimal. The spare capacity can be filled over a number of years with little draw down required. The Hydro Plant will be operating full time as water is already used by the Gympie and district people.  

The proposed three desalination plants will not be required.

The WATER SHARE Tab is recommended reading to this proposal. It is examined on the "WATER SHARE" Page in this website.

In essence the well credential Technical Advisory Panel who examined this allocation recommend that 66% of all water that passes through the Wivenhoe/Somerset dams must reach the Brisbane River mouth. It is now the law (March 2007). I have no problem with that percentage.

However in the writing of the Act the Technical Advisory Panel's advice, that large floods should not be included when calculating the permanent base on which the 66% is calculated, was ignored.

The base on which it was calculated included the four major floods of 1890, 1893 (two) and 1974. The result is that when applied against the 113 years 1894 to 2006 (excluding 1974) the percentage rises to 78%. It cannot be disputed, it is straight forward simple arithmetic. Readers will have no difficulty understanding this when they view the official chart of inflows into the dams for 1890 to 2000 on the "water share" page.

The effective result is that a volume of water equivalent to the proposed, and now cancelled, Traveston dam is redirected from our consumption to the ecology every year. That is 160,000 ML.

In today's terms the massive infrastructure of the Wivenhoe/Somerset Dams, which cost $550 million, would equate to a cost more than $1 billion. It has been reduced from SEQWater's public records of 446,950ML annual yield to allocations of just 286,000ML by the introduction of this Law in March 2007. The fundamental arithmetic flaws need to be corrected. (A yield is the volume that a dam can produce in a year without running dry. It is calculated in this case over 111 years).

While this fundamental arithmetic flaw exists, the Water Strategy for South East Queensland is severely affected and will involve major costs on the drawing board that are not necessary.

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I have set up this web-site for the benefit of my friends, associates and people who I think will thoughtfully examine the situation. While the answer to this puzzle on "drought" "Flood proofing" and additional water available is straight-forward, the underlying base is complex and varied. It requires time and patience to explain the situation and a web-site is the ideal solution. 

I am not a Climatologist, Engineer or Hydrologist. As a Chartered Accountant I am trained to examine the construction and interpretation of data which is readily available. If we encroach on specialist areas we seek guidance.

If others find their way to this web-site then they are welcome but it is their responsibility to assess the evidence and draw their own conclusions.