BORUMBA DAM
EXPANSION ALTERNATIVE
·
Recognize the actual cause
of our recent water crisis and implement a permanent solution.
·
Expand
the capacity of the existing Borumba Dam utilizing the natural features adjacent
to the existing Dam wall thus creating the largest Dam in South
East Queensland
as our major reservoir.
·
Include hydro-electric
power plant in Borumba Dam design to contribute towards power requirements for
pumping between Dams.
·
Connect
Borumba to the Wivenhoe\Somerset Dam System and the South
East Queensland
Water Grid.
·
Manage water between Dams
as required to avoid flood water loss and provide adequate supply.
·
Increase
natural water supply for South
East Queensland
without the requirements of desalination plants.
·
Drought
proof South East Queensland well into the future, provide certainty to the
Brisbane River ecology requirements, and reduce potential flood damage in Grid
Area and Moreton Bay.
Attachments
that support this document can be viewed on our website where an exact copy is
located. www.WivenhoeSomersetRainfall.com
Click the tab
Ron
McMah Imbil
Trevor Herse Gold Coast
John
Hodgkinson
Brisbane
hodgkin@powerup.com.au
********************************************
“Worst Drought”
declaration of depleted dams was fundamentally flawed. As a consequence, solutions proposed were fundamentally flawed
With the Traveston Dam now eliminated the
current perceived “disarray” in our water supply system still has its roots in
the recent depletion of our Dams being erroneously attributed to “the worst
drought in 100 years”.
That phrase applied to our recent water
shortage in our dams, on the basis of official evidence, is a fundamental error.
This, in turn, caused the major proposed solutions of the Traveston Dam and now
ultimately additional Desalination plants, to be diametrically
opposed to a workable and viable solution.
A review of the most recent pronouncements
has revealed that History is repeating
itself. The lack of understanding of the operation of the Wivenhoe dam and
its interrelation with our two main rainfall sources is again showing itself. It
previously led to the cancellation of the Wolfdene dam and the warning signs of
dam failure, evident in dam levels since 1992, being ignored with no explanation
offered.
It took 15 years to acknowledge that the
cancellation of Wolfdene Dam was an error. “Large scale rainfall events”
described by SEQWater as “uncommon events” are our main water supply but are
random occurring, on average, every 3.7 years. The last gap of 6 years, 2001 to
2007 was enough to send us into a panic and blame their absence on the flimsy evidence of a decile map. Decile maps are prone to
statistical aberrations in stable rainfall areas such as our catchments.
There was no drought in
the catchments unless one believes that 80% of the
long term average is a drought. The 20% deficiency was in the non-summer months
that rarely produce inflow. The appearance in the lowest decile being the
“lowest on record” was because there had never been a six year period that
was less than close to 80% of the long term average, 1961 to 1990, since records
were kept. These Bureau of Meteorology records date back to the 19th
century. This is despite a large part of Queensland being correctly drought declared at
that time.
The
action that we must now take is critical to future generations
to avoid a repeat of that panic. Based on past history the gaps in these events
can last up to 14 years. Desalination plants are to be introduced to provide for
increasing population. It takes a desalination plant the size of Tugun 34 years
to fill our dams if no water is taken out. They are pop-guns in attempting to
match “large scale rainfall events” that can fill our dams from scratch in a
few days.
The
proponents of “climate change” should take heed.
The “large scale rainfall events” are said to increase in size. More
importantly, the random gaps will be longer.
If this it is understood, significant
control of rainfall from these events can be achieved by coupling the existing
Wivenhoe/Somerset dam system to an expanded Borumba dam thus doubling the
storage capacity in South East Queensland. The “disarray” can be cleared
up and the end
product made into the World Class Model envisaged
by our Leaders.
Because of the complex nature of this
subject and the need to backup up all statements with official supporting
documentation, I created a web-site for the benefit of my friends. It has come
into general use.
My web-site’s official statistics now
record over 32,000 separate computers accessing the web-site including many
Government Departments, Interstate and Overseas visitors. They are all very
welcome but it is their responsibility to assess the evidence.
Over 70% have added it to their favourites.
In the end the solution appears quite
straight forward and almost simple.
************************
SUMMARY OF THE
SOLUTION
Action
*******************
INDEX
Click on the
headings for the related topics outlined in that section.
Our
catchments rainfall
1.1 Types of rainfall
1.2 Summer rainfall
1.3 Large scale rainfall events
“Large scale
rainfall events” are our main water supply. Their random nature is at the
heart of the problem
2.1 Historical occurrence
2.2 Mathematics of these events
2.3 Observed in the Wivenhoe
2.4 Recent large gap
2.5 Wivenhoe experience
The “worst drought in 100 years” re-examined
3.1 Summer rainfall normal compared to long
term average
3.2 Deficiency of 20% confined to low water producing non-summer months
3.3 Population showed no sudden increase
3.4 Large scale rainfall events missing
3.5 Gap 6 years in large scale rainfall events. Water reserves rescued by 4 near
misses.
Solutions
– “Drought proofing” method to counter “worst drought in 100
years”.
How
do they stand up to a 14 year drought without our main water supply.
4.1 Some good solutions
4.2 Traveston Dam
4.3 Desalinated water
Solution
- Alternative solution based on the knowledge that recent depletion of our dams
was caused by the random nature of “large scale rainfall events”
How do
they provide for the absence of our main water supply for 14 years.
5.1 General outline
statement
5.2 Raising the Borumba dam wall to 2 million ML plus Hydro.
5.3 Managing dam levels
5.4 Spare water storage
5.5 Review and revise “Water Resource (Moreton) Plan 2007” (WRP) to cover
changed storage conditions.
5.6 Degradation of water quality in
Moreton
Bay
minimized
5.7 Allocation of the final 80,000ML, now held in reserve in the
Wivenhoe/Somerset moved permanently to Borumba.
5.8 Summary of additional water available without any conditions
5.9 Additional water available
5.10 Calculating the volume of water that has to flows through the
Wivenhoe/Somerset for the WRP
5.11 Accommodation of the 80,000ML identified by engineers GHD
6.0 The facts at our
disposal
********************
ASSESSMENT OF THE CAUSE OF OUR DEPLETED DAMS AND THE SOLUTIONS
PROPOSED
Our
catchments rainfall
1.1
Types of rainfall and their impact on inflows into the Dams
SEQWater was very clear in the Courier Mail article of the
10th
February 2007 that there are two types of rainfall that create the major flows in the catchments.
The official evidence supports their statements.
Photo : Courier mail Feb 07 types of
rainfall
1.2 The first is summer
rainfall covering the four months December to March. They have provided
54% of all rainfall ever since records were kept. Official records
indicate that it would take 7 to 9 years for this type of rainfall to fill the dams if no
water is withdrawn. Summer rainfall is now well known
to us all.
1.3 The second is “large
scale rainfall events” that occur over a few days being Monsoons, Cyclones
and Rain depressions. They generally cover all of South East Queensland. They
have the capacity to fill
the dams in a few
days. They ignore completely the time of year. The main catchments require
300 to 400mm in those few days. SEQWater describe them as “uncommon events”.
They are in fact quite common occurring on average every 3.7 years using Bureau
of Meteorology data and flood heights. I
have replaced their term with “large scale rainfall events”.
300mm in a few days produces a flood whereas
300mm over 3 months at 100mm a month creates a trickle. They
have the ability to
disguise themselves in official statistics. One half of the 20th
Century in 6 year lots had almost the same rainfall as this 6 year period of
“drought”, 2001 to 2007. Without
a large scale rainfall event in any of them they would have all produced the
same “drought”. The current period was not unique but this fact remained
undetected.
Photo : Rainfall in 6 year lots. Those
on left have no large scale rainfall events
We will find that “large scale rainfall
events” are our major
water supply but are random in their nature with little
reliability in timing.
Click to go back
to index
Photo : contributors to our water
supply
“Large
scale rainfall events” are our main water supply. Their random nature is at
the heart of the problem
2.1 Official records dating
back to 1841 show that large scale rainfall events occur on
average every 3.7 years
with 43 on
record. This is based on official rainfall statistics and backed up by flood
heights at
Brisbane
City
and other Bureau recorded information. Most occur within 4 years.
Photo : "large scale rainfall
events" covering 1841 to 2006
2.2 It is a mathematical
certainty that if most occur within 4 years then those above 4 years will be
fewer but stretch well into the future. It is the events that can occur past the 4
year mark that interest us and created the current problem. Past records show
that they can have gaps of up to 14 years.
2.3 They are observable in
the short life of the Wivenhoe commissioned in 1986. The dam was filled to
overflow in April 1988 and April 1989 causing the acknowledged error of
cancellation of the Wolfdene dam, construction of which had yet to be started.
The then recently completed Wivenhoe was full. However it fell to 70% by 1992.
That should have alerted us to the fact that summer rainfall was inadequate as
far back as 1992.
Photo : Wivenhoe dam level graph
overlaid by large scale rainfall events.
2.4 The Hydrologists of that generation, having experienced a
large gap of 14 years (1974 to 1987) without “large scale rainfall
events”, knew full well that Summer Rainfall was inadequate.
Reading
of the Courier mail indicates the hydrologists of that time were world class
with international experience.
2.5 The Wivenhoe was
refilled from levels as low as 47% a further 4 times, three to overflow. The dam
level graph, which has not been published, records the constant depletion
through the inadequacy of summer rainfall even though rainfall received then
matched the long term average. That graph is attached for convenience of the
reader. All other documentation is contained in the website.
Click to go back
to index
The “worst
drought in 100 years” re-examined
3.1
Official statistics are listed at the head of every page in the web-site which
show that summer rainfall in the
Wivenhoe
catchment was 99.7% of the long-term average for the period of the “worst
drought” being 2001 to 2006. It was 91.3%
in the
Somerset
catchment.
Photos : Bureau rainfall data for Wivenhoe and Somerset
catchments from 1964 to 2006
3.2 The overall rainfall
deficiency of 20% was almost entirely in the non-summer months stretching
over the 8 months April to November. This period normally receives only 46% of
the rainfall and produces little inflow. The 20% deficiency applied fully to the
non-summer period has little influence on the “worst drought” theory.
3.3 Official population
statistics displayed no sudden
uplift. They were predictable and were in
keeping with their predictions.
Photo : Official population statistics showing no
sudden uplift
3.4
What was
missing was a “large scale rainfall event”. We were experiencing one of
the large gaps that, from past experience, can stretch to 14 years. You will see
from the dam level graph the impact that had on dam levels.
Photo : Wivenhoe dam level graph
overlaid by large scale rainfall events. An important document that is not
published elsewhere.
3.5 This gap in
large scale rainfall events lasted 6 years. We were rescued by four “near
misses” that failed to fully cover the catchments and thus failed to develop
their full potential. Cyclone Hamish missed us altogether. They provided 49% of
the increase of 57% in dam levels.
Click to go back
to index
Solutions
– “Drought proofing” method to counter “worst drought in 100 years”
How do
they stand up to a 14 year drought without our main water supply
4.1 In the short space of time
available after recognition that something was wrong, some
very good initiatives were undertaken including raising the wall of the
Hinze dam, water tanks and the re-education of SEQ residents and business to
reduced water methods.
Recycled water was also a good initiative.
However, with low levels of use of the primary water, the low volume produced
would take 21 years to fill the Wivenhoe/Somerset dams from this source if no
water was taken.
The main “drought proofing” methods that received examination were the
Government preferred Traveston Dam proposal and desalinated water.
4.2 Traveston dam proposal was on the
Mary
River
. Both the
Stanley
River
and the
Mary
River
have adjacent catchments. Their sources are in the Mt Mee area. They begin to
flow to the coast by rights but due to some geological anomaly turn west and
find their inland route to the ocean.
They have exactly the same rainfall in
periods without large scale rainfall events and rainfall is received in
exactly
the same pattern. The result under these conditions would not have supplied the
additional water required as summer rainfall is approximately 1/3 of our water
supply. Doubling of that would have left us well short with increased population
requirements.
Photo : Rainfall graph of the Mary and
Stanley Rivers showing the commonality of both Rivers
The Traveston proposal is now consigned to
history.
4.3 Desalinated
water has been again put forward as the only available
option to make up the leeway caused by cancellation of the Traveston. On the
face of it, it may seem reasonable.
It would take the Tugun desalination plant 34 years to fill the
Wivenhoe/Somerset if no water is taken out. (1,560,000ML / 45,000ML = 34 years)
The annualised water from “large scale rainfall events” based on the
measured experience of the Wivenhoe is 417,567ML. To maintain that supply, we
would need not less than 9 desalination plants of the capacity of the
Tugun Plant. (417,567ML divided by 45,000ML = 9.27)
A preliminary cost comparison of moving the
same volume
of water up and down the pipeline to Borumba is that desalination is
50 to 100 per cent more expensive than the Wivenhoe/Borumba operation.
A preliminary cost comparison of moving the
same volume
of water up and down the pipeline to Borumba is that desalination is
50 to 100 per cent more expensive than the Wivenhoe/Borumba operation.
Photos : Pumping calculations for
comparison of Desalination and Pipeline to Borumba at "Household" and
"Wholesale rates".
Click to go back
to index
Solution
- Alternative solution is based on knowledge that the recent depletion of our
dams was caused by the random nature of “large scale rainfall events”
How
do they provide for the absence of our main water supply for 14 years
5.1 General
statement.
Recent history shows that the periods without “large scale rainfall events”
can last up to
14 years. This last “water crisis” which caused us so much
pain, particularly to the people of the Mary Valley, fortunately lasted only 6 years. So how do we
provide counter measures?
Photo : Large scale rainfall events
since 1841 to 2006 together with their probability
The answer requires wider thinking.
There is more than enough water available in the Wivenhoe/Somerset system to
cover the ecology of the
Brisbane
River
, our present requirements and protection of
Moreton
Bay
from damaging flood water
5.2 Raising the
Borumba dam wall to a capacity of 2 million ML will increase the total
storage capacity available in the joint Wivenhoe/Somerset/Borumba to more than
double the current storage capacity being the Wivenhoe/Somerset system.
(Wivenhoe 1,165.000 + Somerset 385,000ML = 1,550,000ML)
5.3
Managing the dam levels at around 50%
gives us capacity in the Wivenhoe/Somerset system to retain 750,000ML for
pumping to the expanded Borumba. Temporary use of a further two metres of the
operating level gives us a further 300,000ML. Thus around 1 million ML can be
pumped to the expanded Borumba at our leisure.
5.4
As “large scale rainfall events” generally cover all of South East
Queensland, the Borumba catchment can
provide a fill of up to 500,000ML and
sometimes more. Thus we have spare water
of around 1.5 to 2.0 million ML available for the ecology and ourselves. That is
about 11 years work for 4 desalination plants the size of Tugun. Smaller plants
were initially proposed.
Photo : Gympie times observations of
the 1999 flood in the Borumba.
5.5
The “Water Resource (Moreton) Plan of 2007 requires
a review to provide for the incorporation of this storage capacity. The Act
provides for change and is designed to be flexible.
Currently Ministers Hinchcliffe and
Robertson are bound by the requirement that 66% of all water that passes through
the Wivenhoe/Somerset system must reach the
Brisbane
River
mouth. People of South East Queensland would be surprised to learn that of the
73% now in our dams, we are only entitled to 1/3 and the rest is for the River.
The Law to monitor and enforce it has been on the internet since January 2009
and is expected to be finalized by December 2009
5.6 In addition it is now known with certainty that
flood
water
degrades the water quality of Moreton
Bay. This water is almost all flood water as witnessed in the short life of the
Wivenhoe Dam, filling the dam from scratch and overflowing a further 4 times.
Photo : Recognized official report
recording a "D" for Moreton Bay caused by flood water
5.7 Of the yield in the Wivenhoe/Somerset established
by the Government of 360,000ML, 80,000ML is not allocated for consumption
apparently because of unforeseen “drought”
possibilities. This can be released with the Borumba backup. (Yield is the
amount that can be drawn from a dam using past rainfall statistics without the
dam failing and is known as HYNF)
5.8 So without
any restrictions or complications, 132,000ML is available
which is almost the size
of the proposed Traveston all three stages. (52,000ML additional yield
from expanded Borumba connected to Wivenhoe + 80,000ML unallocated in the
Wivenhoe/Somerset).
5.9 There is a further
80,000ML identified by engineers GHD when they considered raising the
Wivenhoe dam wall.
However, if the calculations of those who prepared the Water
Resource (Moreton) Plan of 2007 are correct then there is much more water to
consider. For example:
Photo : Engineers GHD calculation of additional water
available if Wivenhoe dam raised.
5.10 Calculating
the annual volume of water through the Wivenhoe/Somerset using the
Government yield information and the requirement of the Water Resource (Moreton)
Plan 2007(WRP).
The yield available for our use or held in reserve is 360,000ML annually
.
The WRP requires 66% for the
Brisbane
River
mouth that leaves 34% of all water that passes through the system for us.
Therefore the volume of water that must pass through the system each year to
comply with that Act is 1,058,823ML (360,000ML divide by 34% X 100% =
1,058,823ML)
.
To gain an understanding of that volume of water, the capacity of the Wivenhoe
Dam is 1,165,000ML.
So a volume of water almost as large as the
Wivenhoe Dam must occur each year to comply with the WRP. An impossible
situation but currently that is the way the Act is written.
5.11 To accommodate
the 80,000ML identified by engineers GHD, how much does the
Wivenhoe/Somerset contribution to the Brisbane
River
have to be reduced?
Under the 66% rule the required volume is 698,823ML.(1,058,823ML -360,000ML). A
reduction of 80,000ML represents 11.5%.
However, the Wivenhoe/Somerset contribution to the
Brisbane
River
is 40% overall. The reduction at the
Brisbane
river mouth is 40% of the required 11.5% = 4.6%.
The
Brisbane
River
mouth requirement of 66% is to be reduced by 4.6% to 61.4% in order to retrieve
this 80,000ML.
Offsetting that reduction is control over flooding in
Moreton
Bay
and controlled releases to suit the environment.
Click to go
6.0
The facts that we have at our disposal are now listed:
Containment of large scale rainfall
events in the Wivenhoe/Somerset system
.
Borumba Dam storage and supply
capabilities including two-way pipeline
to Wivenhoe/Somerset
* The Borumba dam is currently a small dam
of 45,000ML.
* We own all the land via the Qld Government.
* It has a hard rock catchment that is small
at 466 square klms.
* Government appointed engineers GHD
indicated that it could be made into a 2 million ML dam, or higher, making it
the largest dam in Queensland.
* It is a natural amphitheatre.
* It is 60klm from the Wivenhoe dam and
40klm from the Somerset.
* It will require an EIS (Environmental
Impact Study) but has the backing of most in the
Mary
Valley
who have had a link to my web-site for sometime. We have been in close touch.
Of course a dam is already in existence there.
* A much smaller expansion of the Borumba
dam was proposed for the second phase of
the Traveston proposal so no opposition to the principle of expansion
would be expected from the Government.
* The increased yield from the Borumba
expanded would be 52,000ML based on GHD engineer’s calculations of 31,000ML
additional from a much smaller dam which would not
