Chapter 3 - Traveston Crossing Dam and Wyaralong Dam
3.1
The majority of evidence received during this inquiry related to the
proposed Traveston Crossing Dam. The Wyaralong Dam proposal was the subject of
much discussion during public hearings and was also raised in some submissions.
This chapter provides a description of each of these proposals including
evidence received relating to the decision making process, the technical
aspects of the dams, such as site suitability, and the cost of the dams.
3.2
Chapter 4 discusses the social impacts of these two proposals and
chapter 5 discusses the environmental issues relating to both dam proposals.
Proposed Traveston Crossing Dam
3.3
The proposed Traveston Crossing Dam is located 16 kilometres south of
Gympie in the Mary River catchment and will be completed in two stages. Stage 1
is due for completion in 2011 and plans to deliver an additional 70,000
megalitres of water a year. The project will only proceed to Stage 2 if the
additional water storage capacity is required to meet expected demand for water
based on rainfall and usage patterns. The Queensland Government established a
company, Queensland Water Infrastructure Pty Ltd (QWI) to develop the dam and
obtain the approvals required.
Stages of the proposal
3.4
The Queensland Government proposes to develop water infrastructure in
the Mary River catchment in three phases to provide 150,000 ML/a by 2035. The three
phases are:
- construction of Stage 1 of the Traveston Crossing Dam by the end
of 2011;
- raising the existing Borumba Dam by a maximum of 30 metres by
2025; and
- construction of Stage 2 of the Traveston Crossing Dam by 2035, as
required by demand.
3.5
The Queensland Government provided the statistics for the Traveston
Crossing Dam which are detailed in Table 3.1 below:
Table 3.1 – Traveston Crossing Dam –
Statistics for Stage 1 and Stage 2
|
Stage 1 |
Stage 2 |
Anticipated annual yield
|
70,000 ML |
110,000-150,000 ML (includes 70,000 from Stage 1) |
Elevation above sea level
|
71 metres |
79.5 metres |
Water depth at dam wall
|
24 metres |
32.5 metres |
Average depth (in river
channel)
|
12 metres |
16.25 metres |
Average depth
|
5 metres |
8 metres |
Full supply area
|
3,000 ha |
7,135 ha (includes Stage 1 area) |
Total capacity
|
153,000 ML |
570,000 ML (includes Stage 1 capacity) |
Length of Mary River inundated
|
36.5 km |
50.7 km |
Properties affected
|
332 |
597 (includes 332 from Stage 1) |
Houses required for dams and
roads
|
76 |
204 (includes 76 from Stage 1) |
Highway relocation
|
11.94 km |
- |
Road relocation
|
37.29 km |
69.63 km (includes 37.29 from Stage 1) |
Rail relocation
|
- |
3.99 km |
Scheduled completion
|
2011 |
2035 (subject to SEQ demand) |
Source: Queensland Government, Submission
166, p. 121.
The decision and announcement
3.6
The Queensland Government stated that the initial announcement made by
Premier Beattie on 27 April 2006 nominated the Traveston Crossing Dam as a
preferred site subject to further investigation, not as a confirmed site at
that time. The announcement which confirmed the Traveston Crossing Dam as a
preferred site occurred on 5 July 2006.
The Traveston Crossing Dam proposal stood out as being vastly
superior to all other options in terms of hydrological performance and ability
to generate additional water supplies. Consequently, the Queensland Government
announced on 5 July 2006 that Traveston Crossing Dam was the preferred site for
construction of a dam in the Mary Valley.[1]
3.7
The basis for the decision to consider the Traveston Crossing Dam
proposal was the report titled SEQ Regional Water Supply Strategy - Desk Top
Review of Identified Dam and Weir Sites (the GHD Report), written by GHD
Pty Ltd, commissioned by the Queensland Government as part of the South East
Queensland Regional Water Supply Strategy.[2]
The GHD Report was a desk top review which considered existing reports and data
available on dam and weir sites that had previously been identified in the
South East Queensland (SEQ) region. The report included 'detailed estimated
costs to construct dams for a selected number of sites based on information in
earlier reports and estimated indicative costs based on conceptual designs for
a number of other sites or alternative development levels'.[3]
The report then ranked potential development options in terms of potential
yield and unit cost of the dam per megalitre of water delivered.
3.8
The GHD Report identified eighty dam and weir site options which had
been studied in the past. Short listed options were then identified for further
consideration and were reviewed in more detail. The Traveston Crossing Dam
ranked first in terms of potential yield (and storage capacity) being more than
2.5 times greater than the second rating dam and ranked fourth in relation to
the unit cost per megalitre of delivered water.[4]
3.9
The Queensland Government explained why it considered the Traveston
Crossing Dam was a logical source of supply:
...potential yield is not the only factor which must be taken into
consideration in making a final decision on dam location. However, the
assessment of dam options undertaken by GHD showed that there were no other
significantly sized storages other than Traveston Crossing Dam that could meet
the identified requirements. As such Traveston Crossing Dam was identified as a
logical single source to supply the amounts of water required once the other
measures such as demand management initiatives and alternative sources were
considered.[5]
3.10
The committee received some evidence questioning the information
contained in the GHD Report relating to the Traveston Crossing Dam.[6]
Mr Alan Sheridan, a professional civil engineer and Secretary of the Save the
Mary River Coordinating Group, commented on the costing information included in
the GHD Report and stated that the unit cost per megalitre detailed in the
report is not accurate:
...the table in that report is being referred to by the government
as the justification. I have highlighted the proposed Traveston Dam on that
table and it appears as No. 4 on that list. You will see that the yield listed
on there is 215,000 megalitres. We know that it is 110,000. The cost is listed
as $1 billion, we know it is $2.5 billion. When you combine those figures, the
unit cost is $22,727 per megalitre of yield not $4,695, which is listed in that
report. So the report is fundamentally flawed on two accounts, specifically in
relation to the Traveston Dam and more generally in relation to the fact that
it is just a report on dam sites, not a report on providing water. Using the
correct figures, makes the proposed Traveston Crossing dam the most expensive
of any of the dam options considered by the state government.[7]
3.11
The Queensland Government confirmed that the figures for the Traveston
Crossing Dam contained in the GHD Report have since changed and commented:
Storage wise, it is less; from yield it is actually smaller. So
the GHD report, from a volumetric size, is smaller and the yield in the GHD
report is less than the yield we are now taking. GHD was a desktop study and
applied a historical no-failure type, as we have talked about before. We have
now applied a yield from this dam using the new approach, which takes a stochastic
analysis et cetera.[8]
...
Subsequently, more detailed survey information has indicated
that the maximum capacity at the dam site is 570,000 ML. The costings for the
proposed Traveston Crossing Dam provided in the “Water for South East
Queensland: A long term solution” are based on a 660,000 ML dam.[9]
3.12
Many submissions received from the community questioned the basis of the
decision to consider the Traveston Crossing Dam and indicated that it was
purely a political decision. Ms Margaret Bunce commented:
The decision to build this dam seems to be a political one; a
grand gesture made quickly to cover up for lack of planning and proper research
and the failure to implement suitable infrastructure to cope with a rapidly
growing population. This is a problem that has been many years in the making
but has been bought [sic] on by the failure of rainfall in the Wivenhoe
catchment area.[10]
Concerns regarding site suitability
3.13
On 27 April 2006, the Queensland Government announced that the Traveston
Crossing Dam was chosen as a site for further investigation. These further
investigations were 'to be completed within two months and [were] to confirm
that dams could be constructed at these sites and that there were no insurmountable
technical issues'.[11]
The Queensland Government stated that these investigations included:
- geological investigations;
- a concept design for the Traveston Crossing Dam site;
- review of environmental factors;
- environmental comparison; and
- transport infrastructure assessment.
3.14
The committee received evidence from submitters on their inability to
access technical reports and information on the analyses undertaken by the
Queensland Government.[12]
Ms Shirley Edward commented:
To date, the Qld Govt has failed to provide sufficient
information on geological and geotechnical conditions throughout the dam area.
I have been trying to get information regarding these issues since the
announcement was made.
...
The Queensland Government continues to reiterate that it has
nothing to hide. I have repeatedly asked to be provided with a copy of the
Golders Drilling Summary Report. Further, I wish to be provided with answer to
questions that I asked about the geological and geotechnical investigations and
planning processes for the proposed Traveston Crossing Dam.[13]
3.15
Evidence received during the inquiry, questioned the suitability of the
Traveston Crossing Dam site. These questions appear to have been exacerbated by
the unavailability of analysis information and technical reports. Dr David Williams
detailed the ideal characteristics for selection of a dam site and indicated
that you would want: an adequate catchment to supply the storage, a deep valley
to minimize evaporation, a suitable location for the dam wall and a base of low
permeability to minimise potential seepage beneath or under the dam walls.[14]
3.16
Submissions indicated the following concerns with the suitability of the
site:
- the presence of arsenic cattle dips;
- the dam will be shallow and would have high evaporation;
- the alluvial floodplain would result in high seepage and
permeability;
- whether there would be adequate catchment of supply given the
variability of rainfall; and
- stability of the dam floor given the existence of fault lines.[15]
Mr Alan Sheridan stated that:
...Associate Professor David Williams, from the University of
Queensland, who is the individual whom I believe SunWater uses to do their assessments
of seepage and evaporation losses from water storages and who is very well respected
in that field, publicly advised that the level of seepage from the proposed
Traveston Dam, because it is on an alluvial flood plain, could be anywhere
between 0.3 and three metres in depth per year. If the evaporation losses in
that area are 1.4 metres and the dam is an average depth of five metres, it
does not take much of a rocket scientist to work out that there is a very big
risk for a shallow dam in this location.[16]
3.17
QWI requested that SunWater provide an assessment of the anticipated
evaporation and seepage from the proposed Traveston Crossing Dam storage, and
compare the net average evaporation with other storages. The report prepared by
SunWater provided a comparison of net average annual seepage, this is detailed
below as provided by the Queensland Government:
To determine the nett [sic] average annual evaporation from a
storage, the lake evaporation, seepage and rainfall on the storage must all be
accounted for, using the following equation:
Nett [sic] Evap = Pan Evap * Lake Factor + Seepage – Rainfall on
Storage[17]
This has been carried out for a number of storages in Queensland,
using the closest recorded weather data only.
Table [detailing]: Nett [sic] storage
loss
STORAGE |
Evaporation |
Rainfall |
Nett [sic] Evap (mm/a) |
Period |
Hinze Dam
|
1493
|
1280
|
319
|
1995 - 2005
|
North Pine Dam
|
1522
|
1219
|
375
|
1972 - 2005
|
Traveston Dam
|
1448
|
1097
|
521
|
1975 - 2005
|
Borumba Dam
|
1448
|
1079
|
539
|
1976 - 2005
|
Wyaralong Dam
|
1287
|
843
|
574
|
1967 - 2005
|
Lenthalls' Dam
|
1448
|
944
|
674
|
1976 - 2005
|
Ross River Dam
|
2606
|
1044
|
950
|
1970 - 2005
|
Coolmunda Dam
|
1678
|
642
|
1052
|
1974 - 1984
|
Wivenhoe Dam
|
2045
|
740
|
1150
|
1993 - 2005
|
Burdekin Falls Dam
|
1825
|
573
|
1388
|
1994 - 2005
|
Beardmore Dam
|
2067
|
536
|
1480
|
1996 - 2006
|
Note: Care should be taken
in comparing nett [sic] storage losses that have been derived with different
periods of record.
Source: Queensland Government, answer to question on
notice, 30 April 2007 (received 31 May 2007).
3.18
Mr Graeme Newton, CEO of QWI, commented on the evaporation figures for
Traveston Crossing Dam and stated that the net evaporation figure is 520
millimetres per year and the pan evaporation figure is 1.4 metres and explained
the difference between these two figures. The net evaporation figure 'takes
into account the pan evaporation and the lake factor which is attributed to
that and the seepage that is involved and then it includes the rainfall that
actually falls on the impoundment itself. It is a method that has been used
over 20 or 30 years for determination of evaporation under that term ‘net evaporation’'.[18]
3.19
Mr Phillip Moran, Vice-president of the National Aquatic Weed Management
Group provided information on a range of aquatic weeds and specifically
commented on water hyacinth and salvinia which are present in the Mary River
and the risk of creating a river environment that would encourage the growth
and spread of these weeds. Mr Moran commented:
Aquatic weeds are most likely to occur in large slow moving or
stationary water bodies. Areas with high nutrient input are especially
susceptible. If the water is in full sun, and [r]elatively shallow, you are
guaranteed to get aquatic weeds.[19]
...
Earlier today I heard some people talking about the average
depth of this proposed water body and the evaporation rates, and they were
quite scary. If you add a weed such as water hyacinth you can multiply that
result by a minimum of three because it sucks out the water. It is like a pump.[20]
3.20
The fact that the site of the dam wall was moved after the original
announcement caused concern in the community.[21]
Dr David Williams, academic, stated '[t]he first location chosen to locate the
dam wall turned out to be not a good site, and subsequent land investigations
have continued at other potential sites. The first site had of the order of 30
metres of permeable alluvium overlying rock, which would create all sorts of problems
in trying to seal it off to stop seepage coming under the wall. The second
site, I understand, is a much better site but still far from ideal'.[22]
3.21
The Queensland Government provided the following technical evidence
addressing the concerns relating to the alluvial floodplain, an adequate solid
rock foundation and the potential for seismic hazard:
Based on extensive preliminary geotechnical investigations, the
proposed site of the Traveston Crossing Dam is considered suitable for a design
comprising a roller compacted concrete centre section, an earth embankment on
the northern bank and concrete spillway on the southern bank (refer to Section
8.4 of this Submission). It is proposed that a fish passage device will also be
incorporated into the dam design.[23]
...
In the vicinity of the site, the Mary River flows within a broad
alluvial floodplain. Within the floodplain the river has a meandering habit
although there are several straight sections that are interpreted to reflect
bedrock structures. The straight northwest trending section immediately
downstream at the damsite appears to be one such control. Alluvial terraces are
well-developed along this section of the Mary River. At AMTD 207.6km three
alluvial terraces are present across the left bank. The surrounding topography
consists of dissected ridges with many gullies reflecting the dominant
northeast structural trend.[24]
...
To date a total of seventy-six geotechnical boreholes have been
drilled across the sites. This includes forty-six across the AMTD 207.6km
alignment and nineteen across the AMTD 206.7km alignment. Eleven boreholes have
been drilled to investigate the AMTD 207.6km groundwater hydrology. All
drilling data are being incorporated with all available data to construct a
comprehensive damsite geological model. Preliminary reports for forty-one of the
boreholes have been completed and are attached in Appendix B. The remaining reports
are in the process of being completed. The investigations completed to date,
confirm the initial assessment that the foundations along the dam alignment are
suitable for the proposed dam structure and that there are good rock
foundations...[25]
...
A seismic hazard (Earthquake) assessment of the site has been
carried out. This is a probabilistic assessment which employs a seismotectonic
model that considers the seismology (earthquake activity) and geology of the
area in order to estimate seismic activity and frequency. The seismotectonic
model allows for calculations of expected ground motion recurrence at the site,
including peak ground acceleration and response spectra. These parameters allow
the stability of the dam to be checked under earthquake loading. The peak
ground acceleration for the site has been calculated as being slightly above 0.05g
for a return period of 500 years when considering earthquakes of Richter
magnitude ML4 and above. This value is below average by Australian standards.
With these peak ground accelerations earthquake loading will not be a concern
to the dam. The seismic assessment has been reviewed by the Expert Peer Review
panel who have concluded that earthquake loading should not be a concern to the
dam or spillway structures.[26]
3.22
Many submitters and witnesses commented on the fact that the proposed
dam area contains arsenic cattle dips and the potential exists for this to cause
harm when the construction of the dam takes place and water is stored.[27]
Mr Alan Sheridan commented:
It is quite common knowledge that there are hundreds of arsenic
cattle dips, and there were other sorts of chemicals used in them. Most of them
would not be registered. The area has been a dairy industry area for well over
100 years. When the dam is impounded, the water will cause those chemicals to
come to the top and they will end up in the dam. But I do not know whether,
when diluted in that amount of water, that would have any impact. I just do not
know.[28]
3.23
The committee received evidence of an incident on a property where five
cattle died unexpectedly in an area in which drilling activity had been
undertaken. Mr Newton discussed this incident and stated that they undertook
testing of the soil and also commissioned a further study by Golder Associates
who conducted sampling both upstream and downstream of the paddock where the
cattle died.[29]
Mr Newton provided the following comments regarding the soil testing of the
site, the results of the testing and a payment of financial compensation to the
owner of the cattle:
We were focusing on what our activity had been on the site and
whether we had brought anything on to it or created any environment that would have
killed the cows. We were doing soil sampling and testing the drillers’ mud,
which is an inert substance. We tested the soil. We know for a fact that it is
clear, because we have the documentation in relation to it. The testing was
done. It came back with similar results to those DPI obtained. We notified the landholder
of those findings, saying that we had not found anything in the soils.[30]
...
Prior to the completion of the investigations, QWI worked
towards a swift conclusion of financial compensation to the owner of the cattle
to ensure their immediate financial welfare was considered. The settlement was
based on a ‘no admission liability’ that was undertaken as a measure of
goodwill. At no stage did QWI seek to restrict any public comment by the landholder
or the owner of the cattle.
The Golder & Associates investigations found that it was
‘unlikely’ that there was a link between livestock deaths and mineral
accumulation.[31]
Cost of the dam
3.24
Many witnesses and submitters have questioned the true cost of the
Traveston Crossing Dam and have asked for the Queensland Government to provide
a cost/benefit analysis for the proposal.[32]
The Queensland Government, in response to questions relating to the full cost
of the proposal, has continually stated that the cost of Stage 1 of the
Traveston Crossing Dam proposal will be $1.7 billion and the cost of Stage 2 is
approximately $800 million. Table 3.2 below provides a breakdown of the
estimated costs of the dam.
Table 3.2 – Traveston Crossing Dam
Cost Estimates
|
GHD Desktop Report
|
Water for SEQ – A Long Term Solution
|
Traveston Crossing Dam (EL
80m) |
Traveston Crossing Dam Stage
1 (EL 71m) |
Traveston Crossing Dam Stage 2 (EL 79.5m) |
Traveston Crossing Dam – Total (EL 79.5m) |
Dam
|
313.4 |
500 |
30 |
530 |
Land
|
416.4 |
660 |
290 |
950 |
Roads and rail relocation
|
74 |
460 |
20 (rail) - 480 |
480 - 940 |
Other (power,
telecommunication etc)
|
55.5 |
80 |
|
80 |
TOTAL
|
$ 859.3 M |
$ 1,700 M |
$ 800 M |
$ 2,020 – 2,500 M |
Source: Queensland Government, answer to question on
notice, 30 April 2007 (received 31 May 2007).
3.25
Mr Jeff Seeney, Leader of the Queensland Coalition, when asked by the
committee if any estimations had been made in Parliament of the sorts of costs
incurred in the replacement of roads, resumption of land and replacement of the
railway line, responded 'we think that the $1.7 billion that they [the
Queensland Government] talk about to build this dam will end up being closer to
$3 billion before it is constructed, when all of those associated costs are
taken into account'.[33]
3.26
The Queensland Government outlined the elements involved in Stage 1 and
the stated cost of $1.7 billion:
Stage 1 of the dam includes the construction of the
infrastructure itself and the relocation of any associated infrastructure
within the valley—powerlines, roads and so forth— and it includes the land
purchasing associated with that. That is a very broad description.[34]
3.27
The Queensland Government confirmed that the cost of $1.7 billion does
not include Stage 2 of the proposal, the Borumba Dam increase, the relocation
of the railway line needed in Stage 2, the pipeline and the relocation of the
Bruce Highway.[35]
3.28
The Review of Water Supply-Demand Options for South East Queensland –
Final Report (the Review Report) estimated the additional cost of the
delivery system for the Traveston Crossing Dam at approximately $900 million
bringing the estimated cost to $2.6 billion. The Review Report stated:
Costs for stage 1 of the dam are estimated to be $1.7 billion.
This does not include the delivery system (pump stations, pipelines, and
balancing storages) from the dam to the Pine Rivers area. The cost of this
connection is estimated to be of the order of $900 million, giving a total cost
for the stage 1 including delivery network of $2.6 billion.[36]
3.29
Mr Bob Fredman, Director of Engineering, Council of Mary River Mayors
commented on the relative cost of the Traveston Crossing Dam:
The relativity of cost is becoming a more and more difficult
equation. If you look at the true cost—the full cost—of the Traveston Crossing
dam water in Brisbane, it starts to mean that there are more options on the
table that are of equal or lower cost, that we would not have looked at
previously. There is no doubt, given the true cost of Traveston water in
Brisbane, that indirect recycling and desalination come into their own all of a
sudden. We have not had this situation in the past, but all those options are
now on the table and they are all necessary for the future. Basically, the dam
answer is a dinosaur answer. It will be extinct within a short period of time.[37]
The economic impacts
3.30
The committee received many submissions commenting on the prime
agricultural land that the dam will inundate.[38]
Dairy farming represents the largest proportion of farming businesses, however
ginger farming, fruit and vegetable farming and horticulture will also be
affected. The Queensland Dairyfarmers Organisation confirmed that approximately
24 dairy farms will be inundated by the dam which represents approximately 5
per cent of Brisbane's milk supply.[39]
Mr John Cherry, CEO of the Queensland Farmers' Federation (QFF) indicated
that:
Our estimate at this stage is that there is around $20 million
of production that will be impacted on by the dam immediately in stages 1 and
2. Roughly half of that is in dairy...but there is also around $5 million in
horticulture. We are not sure of the exact figure but there has been a lot of
horticultural growth in the Mary Valley and that figure is probably an
underestimate. There is also beef and some other industries in that area'.[40]
3.31
Mr Alan Kirkegard is involved in the grazing industry in Imbil
commented:
We are a clean green agricultural belt, we have rich soils, and
we can grow anything and in large quantities. We are close enough to Brisbane
to make transport costs economical.[41]
3.32
Growcom, the peak representative body for the fruit and vegetable
growing industry in Queensland, requested that industry stakeholders be
involved and consulted by the Queensland Government on issues affecting
agricultural businesses and recommended that:
Growers affected by any new water infrastructure developments
must be fully compensated for any damage or loss to land, crop and business
investments, water or earnings. In addition, the existing water supplies and
reliability for growers outside the inundation area must not be impacted by the
new dam.[42]
3.33
The committee received some evidence expressing concern for irrigators and
the impact of the dam on abilities to maintain access to water allocations.[43]
Mr John Schroder and Mrs Rosalind Schroder, owner operators of a 280 acre
dairy farm which is situated to the north of Gympie and the dam site, stated:
As owners of a 100 megalitre water licence which allows us to
pump from the Mary River (sourced from Borumba Dam), we have grave concerns
about our continuity of water supply for irrigation purposes.[44]
3.34
The Tiaro Shire Council outlined their concerns:
Tiaro and Woocoo, as mainly rural shires rely heavily on
irrigated crop production. If the river is not allowed to flow, crop production
will be drastically affected to the extent of making some properties
economically unviable. Apparently, SunWater have assured some groups of
irrigators that their water allocations will be fully maintained. Their
allocations may well be maintained, but that does not mean that they will be able
to use those allocations.[45]
Proposed Wyaralong Dam
3.35
The Wyaralong Dam is located on the Teviot Brook in the
Boonah/Beaudesert region of South East Queensland (SEQ), approximately 14
kilometres north-west of Beaudesert within the Logan River Basin. Projects
involving the Wyaralong Dam were first considered by the government of the day
in 1990 and possible dates for construction have changed over time and include
2060, 2026 and 2015.[46]
In April 2006, the Queensland Government announced the Wyaralong Dam as the 'second
major dam project as part of the suite of measures to ensure a safe and sustainable
water supply for the SEQ region'.[47]
3.36
The Queensland Government have appointed Queensland Water Infrastructure
Pty Ltd (QWI) to progress the design and construction of the dam. QWI will
undertake geotechnical investigations; assess likely environmental, social and
economic opportunities; and potential impacts of the project, ahead of
commencing the formal assessment and approval processes.[48]
The Queensland Government stated:
The Wyaralong Dam is an integral element of the storage system
comprising the Cedar Grove Weir and the Bromelton Offstream Storage, and will
be operated in conjunction with those assets. The Wyaralong Dam (in conjunction
with the Cedar Grove Weir) will contribute 21,000 ML/a of the projected
additional need for SEQ region by 2051, and its construction is due for
completion by 2011 at a cost of $500 million.[49]
3.37
The Queensland Government provided the statistics for the Wyaralong Dam,
which are detailed in Table 3.3 below:
Table 3.3 – Wyaralong Dam – Statistics
Completion |
Anticipated annual yield:
|
21,000 ML in conjunction with Cedar Grove Weir |
Elevation above sea level:
|
63.6 metres |
Water depth at dam wall:
|
28 metres |
Average depth: (in river channel)
|
14 metres |
Average depth:
|
8.3 metres |
FSL Area:
|
1,230 ha |
Total capacity:
|
103,000 ML |
Scheduled completion:
|
By Dec 2011 |
Total Project Cost:
|
$500 million |
Properties affected:
|
18 |
Houses required:
|
Nil |
Road relocation:
|
10.7km |
Source: Queensland Government, Submission
166, p. 149.
3.38
The committee received a significant amount of evidence from Dr Bradd Witt,
Ms Katherine Witt and Mr Andrew Taylor who state that they are primarily
Wyaralong landholders with relevant experience in environmental management,
environmental change and construction management.[50]
All submissions received which commented on the proposed Wyaralong Dam
questioned the value of the Wyaralong Dam in supplying water to SEQ in terms of
proposed yield and the cost relative to the amount of megalitres supplied.[51]
The announcement and the decision
making process
3.39
The committee received evidence suggesting that the government's
announcement of their decision to proceed with the Wyaralong Dam was unexpected
by members of the affected community who had thought that Tilley's Bridge Dam
at Rathdowney was the likely choice for the dam site.[52]
Claims were also made that requests to the Queensland Government for
information have not been responded to:
There has been a complete lack of transparency in the
Government’s decision making process and information which would clarify the
situation, although having been requested on numerous occasions, has never been
supplied. It has been impossible to find out details of the suitability factors
which were used to determine the choice between the two sites Tilley’s Bridge
on the Logan River and Wyaralong on Teviot Brook as the preferred site for a
dam.[53]
Concerns regarding site suitability
3.40
The Logan and Albert Rivers Catchment Association Inc (LARC) commented
that the Wyaralong Dam proposal is based upon a modelled surplus of water in
the Logan River basin at the Cedar Grove Weir and that 'the data used in the
modelling...relies upon inaccurate data to make this assessment'. LARC put
forward a number of relevant points on various assumptions that they have
identified as flawed:
The past 10 years of the rainfall record are significantly drier
than at any time in the preceding 100 years of rainfall data. The modelling
uses data preceding this period and has not run scenarios based on the recent
climate change influences.
The current Maroon Dam has been unable to supply irrigators with
their current allocation. The water resource plan cannot possibly deliver over
and above what has been coming down the river for the past 3 years without
further restrictions upon existing water users.
The hundreds of unsupplemented licence holders do not have
meters and they have not been monitoring their use and there is no checking of
dam licence provisions to assess the level of water use by unsupplemented
irrigators. The model uses rates of application approximately 60% of the
locally estimated actual use rates.
The groundwater data used for the modelling does not takes into
account the significant increase in the use of groundwater bores across the
catchment. There has been no systematic audit of the number, depth and volume
of bores in the catchment.[54]
3.41
Dr Bradd Witt summarised the reasons why he believes the Wyaralong Dam
'is not a solution; it is a problem':
First, Wyaralong Dam is not viable or efficient, either
economically or from a water supply point of view; second, the decision to
construct a dam at Wyaralong was fundamentally flawed due to the use of
inaccurate, inconsistent and outdated data, regardless of the politics; and,
third, there are numerous vastly cheaper, more flexible and efficient
alternatives to the Wyaralong Dam.[55]
3.42
The committee received some evidence questioning
the yield of the Wyaralong Dam.[56] Mr Newton, stated that the 'Wyaralong will operate in
conjunction with the Cedar Grove Weir and basically the yield of the system is
21,000 megalitres at the Cedar Grove Weir, when the two are operated as a
system'. Mr Newton indicated that the basis for the system yield of 21,000
megalitres is:
...hydraulic modelling that has been undertaken. This hydrograph shows
basically the performance of Wyaralong, this being the storage capacity and
basically the performance of the dam during that time, using a reliability and
yield of what we are talking about—so a draw of 21,000 megalitres at Cedar
Grove Weir.[57]
3.43
The Queensland Government provided the following evidence confirming the
suitability of the site for the Wyaralong Dam:
Extensive geotechnical investigations have identified the
existence of solid rock foundations on both abutments and in the river channel.
These foundations are suitable for all types of dam construction.[58]
Cost of the dam
3.44
The Queensland Government has projected that the cost of the Wyaralong Dam
is $500 million and includes costs for infrastructure relocation and land
acquisition. Mr Newton stated that this does not include any cost associated
with the construction of Cedar Weir Grove.[59]
Dr Bradd Witt commented on the cost of the project:
By way of comparison, everyone acknowledges the expense
associated with Traveston Crossing dam, at $2.5 billion for about 70,000
megalitres per year. However, Wyaralong dam’s woeful contribution of 10,000
megalitres per year, at a cost of half a billion dollars, is 1½ times more
expensive per unit of water than Traveston.[60]
Alternatives to the Wyaralong Dam
3.45
Ms Prudence Firth, a Wyaralong landholder, outlined some alternatives to
the Wyaralong Dam:
There are many options for replacing the small yield of the
Wyaralong Dam (something under 17,000-18,000 ML/a): more demand management initiatives,
recycling, catching stormwater, off-stream storages, water harvesting into
existing dams, desalination, allowing Maroon Dam to fill to capacity, building
Glendower Dam. All of these are more cost-effective than building the Wyaralong
Dam, and they do not have the major social impacts that it has.[61]
3.46
Dr Bradd Witt, Ms Katherine Witt and Mr Andrew Taylor provided the
committee with a report titled Alternative supply options to the proposed Wyaralong
Dam, which identified potential supply options to achieve the
contribution identified by the proposed dam at lower social, economic and
environment cost.[62]
The options identified included:
Option 1: Potential increase in the operational full storage
level of Maroon Dam (up to 76,000ML)
Option 2: Recycled water diverted to Cedar Grove weir or Logan River
via wetland or stored and reused for industry in addition to rain and storm
water capture
Option 3: Intermittent supplementary utilization of water via
the ‘water grid’ from either Hinze Dam and/or the proposed Gold Coast
desalination plant
Option 4: Water harvesting from the upper Teviot Brook at times
of high flow into Moogerah Dam
Option 5: Intermittent use of ground water
Option 6: A reduced scale Glendower Dam on the Albert River to
provide 10,500ML/yr
Option 7: A reduced scale Wyaralong Dam[63]
Conclusion
3.47
The committee received substantial evidence relating to the Traveston
Crossing Dam from members of the communities, farmers, landholders, business
owners and other interested groups, professionals and individuals. Concerns
were raised on a number of issues relating to the dam including the basis for
the decision, the technical aspects of the dam site and the cost of the dam.
The evidence relating to Wyaralong mainly concentrated on the ability of the
dam to provide the stated yield and the modelling data used in making the
decision to proceed with the dam. The social and environmental impacts of both
dams are discussed in chapters 4 and 5.
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