WATER GROUP ADVICE
ON EPBC ACT REFERRALS
QGC referral - 2008/4399
Santos-Petronas referral - 2008/4059
and comments on
AP LNG referral - 2009/4974
Based on information provided by the proponents to close of
business 03/09/10
GAB Discharge Springs: “Scotts Creek” complex (courtesy Fensham and Fairfax, 2008)
Water Group
September 2010
1
Water Group Response to EPBC Act CSG Referrals –
(QGC and Santos)
1. Summary of Key Concerns ........................................................................................ 3
2. Background ................................................................................................................ 3
3. Issues under the EPBC Act ........................................................................................ 5
(a) Listed and threatened species and communities ................................................... 5
i) Results from QGC .............................................................................................. 6
ii) Results from Santos ........................................................................................... 7
iii) Conclusion........................................................................................................ 7
(b) Listed migratory species....................................................................................... 8
(c) Ramsar-listed Wetlands of International Importance ........................................... 8
(d) Other issues .......................................................................................................... 9
(i) Surat Basin ............................................................................................................ 9
i) Groundwater....................................................................................................... 9
a) Volume of groundwater to be co-produced ....................................................... 9
b) Impacts on groundwater systems and structural integrity. ............................. 11
c) Recovery of groundwater systems to pre-CSG conditions............................... 12
ii) Surface water ................................................................................................... 12
iii) Land subsidence ............................................................................................. 12
(ii) Bowen Basin ...................................................................................................... 13
i) Groundwater..................................................................................................... 13
(a) Volume of groundwater to be co-produced .................................................... 13
(b) Impacts on groundwater systems and structural integrity ............................. 14
c) Recovery of the groundwater systems to pre-CSG conditions ......................... 14
ii) Surface water ................................................................................................... 14
iii) Land subsidence ............................................................................................. 14
4. Issues under the Commonwealth Water Act ............................................................ 14
(a) Murray Darling Basin Plan ................................................................................. 14
(b) Section 255A[A] - Independent expert study on the impacts of mining
operations ................................................................................................................. 16
5. References ................................................................................................................ 17
Appendix 1 – Map of EPBC GAB Springs ................................................................. 19
Appendix 2 - Comparative Analysis of proposed Water Extraction by Santos, QGC
and AP LNG with current use in the MDB and GAB ................................................. 20
Appendix 3 – Derivation of the amount of groundwater to be co-produced ............... 24
Overview .................................................................................................................. 24
Walloon Coal Measures ........................................................................................... 24
Other Formations ..................................................................................................... 26
Gubberamunda Sandstone ................................................................................... 26
Hutton Sandstone ................................................................................................. 27
Precipice Sandstone ............................................................................................. 27
Springbok Sandstone ........................................................................................... 27
Summary .............................................................................................................. 28
Bandanna Formation ............................................................................................ 28
Precipice Sandstone ............................................................................................. 29
Appendix 4 – Recommendations from the 255A[A] inquiry into ‘The impacts of
mining in the Murray Darling Basin’........................................................................... 30
2
1. Summary of Key Concerns
This report outlines Water Group’s (WG) key concerns about Coal Seam Gas
(CSG) developments in the Surat and Bowen Basins in southeast
Queensland, and provides advice as to the likelihood that such activities (as
referred in 2008/4399, 2008/4059, 2009/4974) may have a significant impact
on Matters of National Environmental Significance (MNES) and other
Commonwealth policy and program interests.
In summary, the WG has significant concerns about:
a) the general level of uncertainty associated with these proposals, and the
inability of proponents to accurately quantify their individual and
collective impacts over the life of their projects (which is in the order of
30 years);
b) the lack of surety that this represents for the Minister for Environment in
making decisions;
c) the potential for significant impacts on MNES, particularly the listed
Threatened Ecological Communities of The community of native species
dependent on natural discharge of groundwater from the Great Artesian
Basin;
d) the volume of groundwater to be co-produced with CSG, particularly:
i.
impacts on groundwater systems and their structural integrity,
ii.
pressure and volume impacts on GAB aquifers;
iii.
changes to the water chemistry of GAB aquifers;
iv.
the very significant recovery times for groundwater systems to
return to pre-CSG conditions once extractive operations cease,
v.
the volume of salts and heavy metals associated with CSG coproduced water, and the uncertainty around mechanisms for their
disposal, and
vi.
impacts on surface water hydrology from the discharge of CSG coproduced water into the Condamine and / or Dawson Rivers;
e) land subsidence;
f)
impacts on highly productive agricultural land;
g) impacts on Indigenous cultural and spiritual values;
h) broader impacts on Commonwealth and national policy initiatives such
was the National Water Initiative, the CoAG Water Reform agenda, and
the Great Artesian Basin Sustainability Initiative; and
i)
broader impacts on the Murray-Darling Basin and implementation of the
Water Act 2007 and the Basin Plan.
2. Background
The primary gas (and water) extraction proposed in the Surat Basin is from
the Walloon Coal Measures (WCM), which is part of the Great Artesian Basin
(GAB). There are, however, a number of other aquifers above and below the
WCM that will be impacted to some degree from these activities.
3
The primary gas (and water) extraction proposed in the Bowen Basin is from
the Bandanna Formation. Whilst there is likely to be some water loss from
other aquifers, this is not expected to be of the same magnitude as for the
Surat Basin.
The Approvals and Wildlife Division (AWD) has asked WG to contribute to an
assessment of the potential impacts of two proposed CSG developments in
southeast Queensland within the Surat and Bowen Basins (predominantly the
former), which have been referred under the Environment Protection and
Biodiversity Conservation Act 1999 (EPBC Act).
The Environmental Impact Statements and supplementary material provided
by QGC-BG (referral 2008/4399), hereafter referred to as QGC, and SantosPetronas (referral 2008/4059), hereafter referred to as Santos, have been
assessed. Some environmental impact material was also provided by AP LNG
(referral 2009/4974). Further separate technical meetings were held with QGC
(27 June 2010) and Santos (28-29 July 2010 in Roma) by WG officers.
WG officers also attended regular meetings between AWD and Santos and
attended two technical forums at Geoscience Australia where the two
proponents, as well as AP LNG, gave short technical presentations. Through
the separate appraisal by Geoscience Australia, WG received additional
information that was also assessed.
While not part of this current referral process, information from the AP LNG
EIS and other material provided to Geoscience Australia as part of their
independent appraisal was utilised to assess the cumulative impacts of the
CSG developments.
In all, the WG has serious concerns about:
 significant impacts on matters protected under the EPBC Act 1999;
 the management and long-term sustainability of the GAB;
 impacts on the water resources of the Murray Darling-Basin; and
 ongoing implementation of the National Water Initiative and CoAG Water
Reforms.
WG further concludes that the CSG developments trigger the provisions of
s255A[A] of the Water Act 2007; and that there are potential impacts on the
hydrology of the Dawson River.
The information used to provide this advice was that received by close of
business Friday 3rd September, 2010. Supplementary advice will be
forthcoming on information received from the proponents (and AP LNG) since
that date.
4
3. Issues under the EPBC Act
The MNES considered in this advice:



listed threatened species and communities
listed migratory species
Ramsar-listed Wetlands of International Importance
(a) Listed and threatened species and communities.
ADVICE: CSG extraction activities by both Santos and QGC are likely to
have a significant impact on Threatened Ecological Community: The
community of native species dependent on natural discharge of
groundwater from the Great Artesian Basin at the Springsure, Eulo and
Bourke Spring groups.
There are several surveyed locations of the Threatened Ecological
Communities of The community of native species dependent on natural
discharge of groundwater from the Great Artesian Basin (TECs) that may be
impacted by the proposed CSG activities. Known locations of this TEC are
included in the following GAB Spring Supergroups:



Springsure;
Eulo; and
Bourke.
See the map at Appendix 1 for locations of TECs relative to Santos, QGC and
AP LNG’s tenements.
The Springsure springs are generally located ‘up gradient’ of the proposed
CSG developments, with two spring complexes (‘Lucky Last’ and ‘Scotts
Creek’) in the immediate vicinity of CSG extraction activities. The exact
severity of potential impacts cannot be accurately determined with the
information available, nonetheless the amount of water to be extracted is well
above the recharge for the area. This means that a groundwater ‘hole’ will be
formed down gradient from these springs causing groundwater to flow away
from the springs, potentially causing the springs to cease flowing.
There are a number of other TECs within the Springsure Supergroup (for
example, the ‘Dawson River’ and ‘Cockatoo Creek’ spring complexes) which
may also be similarly affected.
Existing development pressures on the Springsure, Eulo and Bourke spring
groups are already severe. For example, Fensham (Fensham et al. 2010; email: R.Fensham-B.Gray, dated 26 Aug 10 at 16.18) indicates that only 4 of
the Eulo springs complexes are still active, with 1 sometimes active; and that
twenty complexes have stopped flowing. For the Bourke Springs, Fensham
5
(R.Fensham et al. 2010; e-mail: R.Fensham-B.Gray, dated 26 Aug 10 at
16.18) reports that 8 springs complexes are active, 22 are sometimes active,
and 31 have stopped flowing.
The Eulo and Bourke Spring Supergroup TECs are down gradient of the
proposed CSG developments and are thought to be ‘fed’ by the Hooray
Sandstone aquifer, which is the lateral equivalent of the Gooberamunda
Sandstone that is present in the CSG development area.
While the Gooberamunda Sandstone is not directly connected to the WCM,
modelling results by both proponents (and AP LNG) clearly indicate that the
pressure in the Gooberamunda Sandstone will be reduced as part of the CSG
developments. From the data presented in the AP LNG modelling (the only
regional modelling available) drawdowns of approximately 4m to 13m lasting
for at least 70 years have been interpreted. This would result in up to 209GL
being ‘lost’ from this formation during the life of the CSG development.
Whilst pressure decreases are felt ‘immediately’ across an aquifer, the size of
the Gooberamunda-Hooray Sandstone is likely to attenuate a pressure
decline before it impacts on the Eulo or Bourke Springs. However the nature
of the springs means that a decrease as small as 10cm would impact on flow
at the Eulo and Bourke spring groups. From the modelling presented, it is not
possible to assess such an impact and further analysis is required.
It is important to note that recharge into the GAB is estimated at 323GL/year
(Kellett et al 2003). Within the Surat groundwater management zone, where
the CSG developments are to take place, the total recharge for the Kimbarilla,
Mooga, Gubberamunda, and Springbok Sandstones is 60ML/yr (Kellett et al
2003). This equates to 1,800ML (or 1.8GL) over a 30 year period – the
approximate lifetime of the CSG extraction – which is only 0.1% of the
groundwater to be lost through Coal Seam Gas extraction from the
Gubberamunda Sandstone alone.
From the limited data available, it can be assumed that the Eulo and Bourke
springs are fed by the Gubberamunda Sandstone (and its lateral equivalent
the Hooray Sandstone); the amount of water that is predicted to be extracted
is larger than the amount of recharge into the Gubberamunda Sandstone.
This means that there is likely to be a reduction in the volume of water flowing
to the Bourke and Eulo Springs, given current groundwater flow rates, in
about 400,000 - 500,000 years. However, given the very low hydraulic
gradient, the development of a pressure low may result in a reversal of
hydraulic gradient, thereby moving groundwater away from the Bourke and
Eulo Springs and resulting in a significantly earlier impact.
i) Results from QGC
There is concern that TECs reliant on spring complexes within a 50km radius
of QGC’s northernmost tenements will be significantly impacted by cumulative
6
drawdown effects, if not directly by QGC’s activities alone. Those TECs of
concern include those dependent on discharge springs at Scotts Creek,
Dawson River 8, Cockatoo Creek, Dawson River 5 and Dawson River 2 (see
Appendix 1).
QGC considers there will be no impact on Springsure TECs and that impacts
on other aquatic or stygofauna communities are unlikely. The modelling
conducted by QGC uses a ‘constant head boundary’ condition at the edge of
their model(s).1 The use of such a condition would preclude any assessment
of impacts beyond the model boundary. This also means that impacts on the
Eulo and Bourke Springs have not been assessed.
ii) Results from Santos
Santos has confirmed it does not believe that it has any discharge springs
supporting TECs on or near its tenements. This view is in conflict with the
TEC Recovery Plan dataset (Fensham et al. 2010) held by the Department of
Environment, Water, Heritage and the Arts, and is also in conflict with expert
advice received from the author of the Recovery Plan for the TECs (e-mail:
R.Fensham-B.Gray, dated 26 Aug 10 at 16.18).
The data and advice to date confirm that the mapping data supporting the
Listing and Recover Plan for the TECs is correct, and that there is one spring
complex supporting the TECs inside or adjacent to Santos tenement PL99 (in
their Fairview Gas Field), and another approximately 13km southeast of
Santos tenement PL100. Other TECs that are likely to be indirectly impacted
by Santos’ CSG extraction activities via cumulative impacts are approximately
65km East of Santos’ tenements and approximately 30km North of QGC’s
tenements (near the town of Taroom) (see Appendix 1).
Santos has not assessed impacts on any of the GAB Spring Supergroups. At
the meeting between AWD, WG and Santos on 21 July 210, Santos advised
that the modelling detailed in their EIS was ‘inadequate’ and that they were
developing new models for both the Surat and Bowen Basins. Their revised
modelling was not available at time of writing, meaning that impacts on the
Eulo and Bourke Springs have not been assessed by either proponent.
iii) Conclusion
Both proponents conclude that their CSG developments will have no impact
on TECs inside their tenements nor in the greater CSG development area.
However, as noted above, neither proponents’ modelling is capable of
ascertaining impacts on spring complexes outside their tenement area, such
as the Springsure, Eulo and Bourke GAB Spring Supergroups, nor do they
fully acknowledge cumulative impacts on TECs.
1
A constant head boundary represents an equipotential line. That is, the head always remains the same (Fetter
2001). This means that water constantly flows into the model from the boundary and there will be no modelled
impacts outside the boundary. A constant head boundary is normally used where there is a large water body where
the level does not measurably change e.g. the sea.
7
From the water balance and ‘area of impact’ assessments presented above,
WG concludes that there is a significant short term risk to these TECs and
spring complexes through pressure decline, and an unquantified long term
risk due to reduction in groundwater flow which would need to be further
assessed.
(b) Listed migratory species
ADVICE: CSG extraction activities by both Santos and QGC are unlikely
to have a significant impact on listed migratory bird species.
The major potential threat to listed migratory bird species is through their
opportunistic use of storages used for untreated CSG co-produced water,
which is highly saline and contains varying concentrations of heavy metals.
However, there is no conclusive evidence that CSG extraction activities will
pose a significant threat to migratory bird species.
(c) Ramsar-listed Wetlands of International Importance
ADVICE: CSG extraction activities by Santos and QGC are unlikely to
have a significant impact on the ecological character of Ramsar
Wetlands of International Importance.
However, given the uncertainty surrounding groundwater inflows, and
potential surface water connectivity during peak flow events, significant
impacts on the Narran Lakes Nature Reserve cannot be completely ruled
out.
There are two Ramsar-listed Wetlands of International Importance, both of
which are a significant distance from the proponents’ tenements:


The Gwydir Wetlands; and
Narran Lakes Nature Reserve.
The Gwydir Wetlands are the closer of the two Ramsar sites but are not
hydrologically connected via surface or groundwater systems to the proposed
gas fields. There is no evidence that CSG extraction activities will pose a
significant threat to the ecological character of the Gwydir Wetlands.
Narran Lakes lies downstream on the Condamine River from the CSG
developments. The main concern is large scale flood events, as seen earlier
in 2010 in this part of southeast Queensland, which could overtop the brine
storage basins thereby mobilising salts and associated heavy metals
downstream and into the Narran Lakes.
8
There is little evidence of groundwater flow into the Narran Lakes,
consequently the drawdown in groundwater levels by the CSG developments
are not expected to have a significant impact on the ecological character of
Narran Lakes. Given the level of uncertainty surrounding groundwater inflows
to Narran Lakes, and to provide increased surety, further investigations and
analysis is required to ascertain any level of connection.
The recent report by Hillier (2010) indicates that the drawdown in the WCM
will result in a reversal in groundwater flow meaning that groundwater in the
Condamine Alluvium will flow into the WCM. Potentially this could result in an
increase in the loss from the Condamine River into the alluvium. However,
since the groundwater level in the Condamine Alluvium is already below the
bed of the Condamine River the risk of increased loss of surface water from
the CSG proponents is interpreted to be low.
WG recommends conditioning any approvals to ensure there are no impacts
on Ramsar-listed Wetlands of International Importance.
(d) Other issues
A comparison of projected groundwater extraction from the CSG
developments and current extractions in the Murray Darling Basin and Great
Artesian Basin is presented in Appendix 2.
(i) Surat Basin
i) Groundwater
The groundwater systems of the Surat Basin form part of the GAB. Most of
the aquifers - Mooga, Gubberamunda, Springbok, Hutton and Precipice
Sandstones - are used for pastoral activities and town water supply.
Groundwater from the WCM is also used in some areas.
In many areas the Surat Basin is overlain by sediments of the Murray Darling
Basin, notably the Condamine Alluvium. As the WCM subcrop a significant
portion of the Condamine Alluvium there is the potential for extraction of
groundwater from the WCM to impact on groundwater levels in the Alluvium,
as discussed in section 4.
Current groundwater use in this area of the GAB is 549GL/yr (AWR 2005).
Estimated groundwater extraction for the MDB is in the order of 1 832GL/year
(CSIRO 2008b).
a) Volume of groundwater to be co-produced
Both the proponents (and AP LNG) intend to lower groundwater pressure in
the WCM by at least 400m, over most of the area, to approximately 30-35m
above the top coal seam in the WCM. Based on this they have provided
9
estimates of their expected cumulative water production and predict
approximately 1,819GL of co-produced groundwater in total from the CSG
developments (QCG – 887GL; Santos – 140GL; AP LNG 792GL). It is not
clear as to whether the production forecasts provided by the proponents
(including AP LNG) is from the WCM only or from all formations in the Surat
and Bowen Basins. Furthermore, as no information has been provided on
groundwater production from individual wells to confirm this volume, a number
of sources and methods were used to confirm the veracity of this prediction
and these are presented in Appendix 3.
The results of this analysis indicates that from the WCM alone between
approximately 229 to 23,000GL (with a most likely range of approximately
6,000 to 14,000GL) of groundwater will be co-produced by CSG operations by
the two proponents and AP LNG (Appendix 3).
These volumes do not include groundwater from the Springbok Sandstone
which both the proponents (and AP LNG) agree is in hydraulic connection
with the Walloon Coal Measures. This means that, based on the production
details of the proponents (and AP LNG) the Springbok Sandstone (and the
top of the WCM) will be de-watered. This will result in a further 76 to
21,000GL (with a probable range of 8,000 to 13,000GL) of groundwater being
produced (Appendix 3).
It has not been possible, at this stage, to determine whether groundwater from
the other sandstone aquifers (Gubberamunda, Hutton and Precipice) will
actually be extracted by the proposed CSG operations or whether it will just
be ‘lost’ from these formations due to an increase in vertical leakage.
However, the calculations shown in Appendix 3 indicate that a further 1.3 to
661GL (with a most likely range of 35 to 411GL) of groundwater will be ‘lost’
as part of the CSG developments by the proponents (and AP LNG).
This means that the total estimated volume of groundwater to be produced
(and lost to the GAB as a whole) is most likely in the order of 14,035 to
27,411GL.
It should be noted that a best case scenario for total water extraction, from our
analysis, ranges from 307GL – about 6 and a half times less than that
predicted by the proponents (including AP LNG) – to approximately 45,000GL
– 22 times more than predicted by the proponents. Hence the expected water
production from the proponents (including AP LNG) can be interpreted to be
extremely conservative.
The amount of water that could be co-produced may be greater than these
estimates if the work conducted by Hodgkinson et al (2010) looking at carbon
geostorage potential is correct. This study analysed the results of drill stem
tests in the Surat and other basins. This analysis clearly shows that in some
areas the WCM, the Hutton Sandstone, Evergreen Formation, and the
Precipice Sandstone are in ‘vertical communication’. Further the paper states
that ‘there is vertical hydraulic communication between the Hutton Sandstone
10
and the Springbok Sandstone through the Walloon sub-group’ (Hodgkinson
2010).
If the area of ‘vertical communication’ is extensive (only 10 bores were
analysed over an area of approximately 300 by 200km) then the impact on the
Hutton and Precipice Sandstones would be even greater than that predicted
by the proponents (and AP LNG) and this analysis. The fact that one of the
bores analysed is very close to the centre of the proposed QGC and AP LNG
operations means that, in the area of the gas fields, groundwater extractions
are likely to be greater than those predicted by the proponents or by the
analysis presented in Appendix 3.
b) Impacts on groundwater systems and structural integrity.
As noted above, the proponents are proposing to drawdown the pressure of
the WCM by at least 400m below the top of the formation. The Springbok
Sandstone unconformably overlies the WCM and, largely, is in hydraulic
connection with the WCM. This means that the Springbok Sandstone (and the
top part of the WCM) will be, effectively, dewatered. The likely consequences
of this are:
1. The Springbok Sandstone, which is currently a confined aquifer, will
become an unconfined aquifer. Once a confined aquifer becomes unconfined
its properties change. This means that the aquifer will no longer be able to
‘store’ as much water as it is currently able and will also lose its elasticity,
resulting in a greater level of subsidence.
2. A large, both vertically and horizontally, ‘de-pressurised’ zone will be
produced. Whilst both proponents acknowledge that there will be some
pressure reduction in overlying (e.g. Gubberamunda Sandstone) and
underlying (e.g. Hutton Sandstone) aquifers, relative to the WCM, these over
and underlying aquifers will remain pressurised.
Given that the pressure heads of the underlying aquifers will be some 300m
above this depressurised zone this is likely to result in an increase in vertical
groundwater flow from these aquifers towards the WCM. Further, this
‘artificial’ pressure differential may cause previously ‘sealed’ faults and
fractures to become more open, resulting in increased groundwater flow
between formations. This may result in ‘losses’ but, perhaps more importantly,
a mixing of different groundwaters, with subsequent impacts on water quality.
The impact of establishing such a de-pressurised zone between two
pressurised systems is unknown. There does not appear to be an example
anywhere else in the world of such a situation being produced - a fact
acknowledged by AP LNG staff at their presentation on 11 August 2010
(A.Mosur, pers. comms. 2010). Hence, any impacts can only be inferred.
The proponents intend to ‘fracc’ many of their production bores to increase
production rates. This is not expected to be a problem in hydrological terms
unless propagation occurs along an unidentified fault or major fracture,
11
thereby increasing the amount of vertical leakage. Whilst this risk is
interpreted to be low in a ‘natural state’, the process in an area that has
become so de-pressurised may result in a greater than expected propagation
outside the WCM, thereby increasing vertical leakage.
c) Recovery of groundwater systems to pre-CSG conditions
From all the information provided to date, including that from AP LNG, there is
no indication when any of the systems affected by the CSG developments will
return to pre-CSG conditions.
QGC states that the WCM (this includes the Springbok Sandstone) will not
begin to recover until 70 years after CSG production ceases. In QGC’s gas
fields, its data shows that the Springbok, Hutton and Precipice Sandstones
will not have recovered after 200 years. Whilst the residual drawdown is
modelled to be quite small, a simple extrapolation for the Hutton Sandstone
would indicate that recovery will take in the order of 1,000 years.
As Santos has requested that their modelling in the EIS not be used and its
new modelling was not provided in time to be included in this assessment, it
was not possible to accurately analyse the impacts of their extractions.
From the AP LNG modelling, the Gubberamunda Sandstone (the lateral
equivalent of the Hooray Sandstone) will not have returned to pre-CSG levels
by 3100.
Therefore it can be concluded from the proponents’ modelling that the legacy
effects of the CSG developments are considerable, with at least 1,000 years
passing before this part of the GAB will return to pre-CSG levels.
ii) Surface water
The current average annual surface water resource in the CondamineBalonne region is around 1,305GL/year (which is 8.5% of the total in the MDB
-23,417GL/year) (CSIRO 2008a, 2008b). The current level of use for the
region is extremely high – >722GL/year of the average available surface
water is diverted for use (which equates to 55% of the region’s available
resource) (CSIRO 2008a).
The production of exceptionally large quantities of CSG water, and the
subsequent discharge of desalinated water, represents a significant impact on
the hydrology of surface water streams in the Condamine River. The issue is
exacerbated if water is discharged to ephemeral stream segments, where the
steady release of water adversely impacts on the no-flow and, to a lesser
degree, low-flow periods of the River’s flow regime.
iii) Land subsidence
From the original EIS, QGC indicate that up to 30cm of land subsidence will
occur. The Santos EIS indicates a similar level of subsidence.
12
After questions were raised in preliminary drafts of the Geoscience Australia
independent assessment, both proponents have since significantly lowered
the expected level of subsidence. This raises questions as to the veracity of
the original assessment (no information was provided in the original EISs as
to how the level of subsidence was calculated) and why the amount of
subsidence, after the question was raised, was reduced.
Previous extraction in this part of the GAB is reported to have lowered the
pressure head by 100m in some areas. Unpublished information
(M. Habermehl 2010, pers. comms.) indicates that this has resulted in land
subsidence in many areas of several metres. For example, the cement collars
around bores drilled early last century now stand well above the ground
surface. This would indicate the further, significant, land subsidence is likely to
occur and is at odds with the predictions of the proponents.
(ii) Bowen Basin
i) Groundwater
(a) Volume of groundwater to be co-produced
Much less groundwater is expected to be extracted from the Bowen Basin
fields due to the lower permeability of the rocks of the basin. Santos will be
producing from both the Arcadia and Fairview fields. For the Fairview field
Santos indicates that 98GL of groundwater will be extracted from this field. A
similar analysis to that done for the Surat Basin above indicates a most likely
range of groundwater extraction of 55 to 103GL (Appendix 3). This gives a
greater level of confidence that the predicted groundwater extraction will be
closer to the Santos prediction (it should be noted that this gives confidence in
the analysis for the Surat Basin).
The major concern of over extraction as part of the CSG developments is with
the Precipice Sandstone. As noted previously the Santos staff consider the
modelling detailed in the EIS to be ‘inadequate’ so it is difficult to quantify
potential impacts. Data from AP LNG indicates that there has been little
impact on the Precipice Sandstone from current extraction. This may be due
to the nature of the contact between the Bandanna Formation and the
Precipice Sandstone. The contact is unconformable and hence the top of the
Bandana Formation would have been subject to weathering before deposition
of the Precipice Sandstone. This may have decreased porosity and
permeability to a point whereby groundwater flow between the two formations
is highly constrained.
However this lack of apparent impact on the Precipice Sandstone may be due
to the current low level of production and once full scale production
commences impacts will be more apparent.
13
Consideration also needs to be given to potential cumulative impacts due to
production from the Roma field which could intersect with production from the
Fairview and potentially Arcadia fields. This would be compounded if greater
hydraulic connection between the WCM, Hutton and Precipice Sandstones
was discovered between the Fairview and Roma fields.
(b) Impacts on groundwater systems and structural integrity
The rocks of the Bowen Basin are older than those of the Surat Basin.
Consequently they have undergone a higher level of ‘deformation’ and can be
considered to be ‘more compacted’. This means that the generation of a
pressure ‘hole’ in the Bandanna Formation will not have as potential great an
impact as for the WCM. Hence there is a much lower concern as to any
impacts on the structural integrity of the groundwater systems.
c) Recovery of the groundwater systems to pre-CSG
conditions
As the groundwater modelling supplied by Santos in their EIS is ‘inadequate’
no interpretation was possible to determine how long it would take the
aquifers to return to pre-CSG condition (noting the new Santos modelling was
unavailable at time of writing).
ii) Surface water
There is no interpreted impacts on the surface water systems from the CSG
developments other than those that may potentially arise from the discharge
of treated water.
iii) Land subsidence
As noted above the rocks of the Bowen Basin are interpreted to have a
greater structural integrity than those of the Surat Basin. Hence any
subsidence measurable at the land surface is likely to be smaller and more
isolated.
4. Issues under the Commonwealth Water Act
(a) Murray Darling Basin Plan
The Murray Darling Basin Plan will provide a framework for setting
environmentally sustainable limits (known as sustainable diversion limits) on
the amount of surface water and groundwater that can be taken from the
Basin.
The Condamine Alluvium, one of the most heavily extracted aquifers in the
Murray Darling Basin, is present over much of the proposed CSG
14
development area. For a significant proportion of this area, the Condamine
Alluvium is directly underlain by the WCM.
Monitored groundwater extraction in the Condamine-Balonne region for
2004/05 is 160GL/year and 97% of this occurs in the Upper Condamine
catchment (CSIRO 2008a). This volume is primarily based on metered use,
and the total monitored and unmonitored groundwater use in the Upper
Condamine is thought to be around 25% higher (CSIRO 2008a). Current
extraction is already unsustainable in 15 of the 22 groundwater management
units (GMUs) in the region, where extraction in these GMUs is more than
double the average potential rainfall recharge. Extraction in six of these
GMUs is more than five times the average potential rainfall recharge. In the
area of the Upper Condamine that is modelled for groundwater, extraction
(currently 47GL/year) exceeds recharge by 38% and recharge is historically
exceeded in more than 90 percent of years (CSIRO 2008a).
According to CSIRO (2008a), if groundwater extraction in the Upper
Condamine sub-catchment were allowed to increase to the current entitlement
levels, the system would be severely over-allocated and additional streamflow
impacts would occur. Furthermore, according to both Hillier (2010) and
CSIRO (2008b), the GAB Alluvial GMU is connected to the surface water
system, and foreseeable increases in extraction (not including CSG water
extraction) will reduce streamflow by 5 to 6GL/year.
From previous studies, Lane (1979) indicated that where the WCM directly
subcrop the Condamine Alluvium the groundwater flow direction is generally
from the WCM to the alluvium. This is not surprising, given the pressure head
in the WCM. This conclusion also supported by Huxley (1982a, 1982b), who
indicates inflow from the WCM into the Condamine Alluvium. There is no
record of the amount of inflow from the WCM into the alluvium.
The recent publication by Hillier (2010), clearly re-affirms that groundwater
from the WCM flows into the Condamine Alluvium and that a reduction in the
water levels (pressure head) in the WCM will result in a reversal of
groundwater flows. That is, groundwater (and potentially surface water) from
the Condamine Alluvium will flow into the WCM. Such groundwater losses
would be considered as ‘take’ under the Water Act 2007 and would need to
be taken into account by the Queensland Government in complying with the
sustainable diversion limit.
As the sustainable diversion limit for the Condamine Alluvium will be set by a
prescribed groundwater level (T. McLeod pers. comm. 2010) such a loss of
groundwater has significant implications for the management of this system
under the Basin Plan.
There are no implications for the Bowen Basin CSG developments under the
Water Act 2007 as it lies outside the boundaries of the Murray-Darling Basin.
15
(b) Section 255A[A] - Independent expert study on the impacts
of mining operations
Section 255A[A] of the Water Act 2007 on the ‘mitigation of unintended
diversions states that:
“Prior to licences being granted for subsidence mining operations on
floodplains that have underlying groundwater systems forming part of the
Murray-Darling system inflows, an independent expert study must be
undertaken to determine the impacts of the proposed mining operations on
the connectivity of groundwater systems, surface water and groundwater
flows and water quality”.
The preconditions for triggering this provision and necessitating an
independent expert study are:

It needs to be a subsidence mining operation;

It needs to be on a floodplain; and

It needs to impact on MDB inflows.
The location of the proposed CSG developments in Queensland and the
impacts of the groundwater extraction as part of these developments results
in all of these preconditions being met.
Such a study would need to identify issues and make recommendations in
regards to what matters a state or Commonwealth decision maker must take
into account before a licence is granted allowing CSG developments to
commence.
In August 2009, proposed CSG activities in the Namoi region of the MDB
triggered Section 255A[A] of the Water Act. Consequently, the Environment,
Communications, and the Arts References Committee was tasked by the
Senate to conduct an inquiry into ‘The impacts of mining in the Murray Darling
Basin’. One recommendation from the inquiry states that it:
Recommends that the Commonwealth Government works to ensure the prevention of new
mines or extractive industries in the Murray Darling Basin if their impacts on water resources
are inconsistent with the Basin Plan.
See Appendix 4 for the complete list of recommendations from the
Environment, Communications, and the Arts References Committee.
16
5. References
Australian Water Resources (2005). A baseline of water resources for the
National Water Initiative. National Water Commission.
CSIRO (2008a). Condamine-Balonne Region Fact Sheet. Murray-Darling
Basin Sustainable Yields Project: A brief guide to the key findings from the
CSIRO Murray-Darling Sustainable Yield Project report on the CondamineBalonne region. June 2008. CSIRO, Australia.
CSIRO (2008b). Water availability in the Murray-Darling Basin: A report to the
Australian Government from the CSIRO Murray-Darling Basin Sustainable
Yields Project. October 2008. CSIRO, Australia. 67 pp.
CSIRO (2008c). Presentation of Results from the Condamine-Balonne and Moonie
Regions, Murray-Darling Basin Sustainable Yields Project . Key findings from the
CSIRO Murray-Darling Sustainable Yield Project report on the Condamine-Balonne
region. June 2008. CSIRO, Australia. 27 pp [www.csiro.au/resources/CondamineBalonneMooniePresentation.html].
Environment, Communications, and the Arts References Committee Report,
‘The impacts of mining in the Murray Darling Basin’
http://www.aph.gov.au/senate/committee/eca_ctte/mining_mdb/report/report.p
df, accessed 10/09/2010
Fetter, C.W., (2001). Applied Hydrogeology. Prentice-Hall Inc, USA.
Hillier, J.R., (2010). Groundwater connections between the Walloon Coal
Measures and the Alluvium of the Condamine River. A report for the Central
Downs Irrigators Limited.
Hodgkinson, J., Hortle, A., and McKillop, M. (2010). The application of
hydrodynamic analysis in the assessment of regional aquifers for carbon
geostorage: preliminary results for the Surat Basin, Queensland. APPEA
Journal 50, 445-462.
Huxley, W.J., (1982). The hydrogeology, hydrology and Hydrochemistry of the
Condamine River Valley Alluvium. Project Report Queensland Institute of
Technology, Brisbane.
Kellett, J.R., Ransley, T.R., Coram, J., Barclay, D.F., McMahon, G.A., Foster,
L.M., & Hillier, J.R., (2003). Groundwater Recharge in the Great Artesian
Basin Intake Beds, Queensland. Final Report for NHT Project #982713
Sustainable Groundwater Use in the GAB Intake Beds. Queensland, BRS,
Natural Resources and Mines, Queensland Government.
17
Lane, W.B., (1979). Progress report on Condamine underground investigation
to December 1978. QWRC Groundwater Branch Report, June 1979.
(Queensland Water Resources Commission).
Qld DERM (2005). Hydrogeological Framework Report for the Great Artesian
Basin Water Resource Plan Area (Version 1.0). Report prepared by the
Queensland Department of Natural Resources and Mines, Brisbane
[www.derm.qld.gov.au/wrp/gab.html#maps].
18
Appendix 1 – Map & Images of EPBC GAB Springs
19
GAB Discharge Spring: Lucky Last
GAB Discharge Spring: Scotts Creek
Image from 2008 survey (courtesy Fensham and Fairfax, 2008)
Image from 2008 survey (courtesy Fensham and Fairfax, 2008)
Image from pre-2008 survey (courtesy Fensham and Fairfax, 2008)
Image from pre-2008 survey (courtesy Fensham and Fairfax, 2008)
20
Appendix 2 - Comparative Analysis of proposed Water
Extraction by Santos, QGC and AP LNG with current
use in the MDB and GAB
WG have concerns about the disproportions between the amounts of water
currently extracted from the Condamine and Balonne Catchment of the MDB
and the Great Artesian Basin and the amount proposed to be extracted and
returned by CSG proponents.
All three CSG proponents plan to discharge a portion of co-produced water
into either the Dawson River (Santos) or into the Condamine and Balonne
Catchment (QGC and AP LNG). Under the Queensland Petroleum and Gas
(Production and Safety) Act 2004, the co-produced water is owned by the
proponent and is, therefore, theirs to sell. WG preference is for natural
systems to be returned to a pre-CSG development state as soon as is
possible, and that the maximum amount of extracted groundwater be reinjected to, if possible, the same or surrounding aquifers and any co-produced
water that cannot be reinjected be returned to the environment as surface
discharge into the Condamine and Balonne Catchment of the MDB. This
would mean that Santos would need to reconsider its proposal to their
‘Dawson River Beneficial Use Discharge Scheme’.
Based on estimates provided by Santos, QCG, and AP LNG in their EIS
documentation, GSG water extractions from these three proponents may total
around 1 819GL over the 30 year life expectancies of their respective projects.
WG conclude that these estimates are likely to be “conservative”, and that the
total estimated volume of groundwater to be produced (and therefore “lost” to
the GAB) is likely in the order of 14,035 to 27,411GL.
This may be as high as 45,000GL.
By way of comparison, the volume of the average annual surface water
resource for the entire MDB is approximately 23, 417GL/year (CSIRO 2008c).
CSIRO also estimate that surface water use across the MDB is in the order of
11,327GL/year (CSIRO 2008c) – which is 48% of the available surface water
resource (and is considered a very high and largely unsustainable level of use
(CSIRO 2008c)).
Estimated groundwater extraction for the MDB is in the order of 1,832GL/year
(CSIRO 2008c). This level of extraction represents some 16% of the total
water use in the MDB (CSIRO 2008b). However, this estimate excludes
extraction from confined aquifers of the Great Artesian Basin that underlie the
MDB. Consequently, the actual level of extraction may be up to 25% higher
(CSIRO 2008c).
21
Surface Water
Region
Groundwater
Region
Total Available
Resource /
Annual
Available
Resource
DEWHA estimated CSG extraction by
Santos, QGC, & AP LNG (proponents
numbers):
Great Artesian Basin:
Estimated
Average
Annual
Extraction
467 to 914GL/a
(61GL/a)
Based on a 30yr period
Total available resource =
Average Annual Recharge =
Total savings under GABSI 1 & 2 =
Murray-Darling
Basin4
na
na
Estimated Total
Year Use
Extraction
14, 035 to
27, 411GL
(18,19GL)
64,900,0001 GL
3232 GL/a
167.3193 GL/a
23, 417 GL/a
11, 327GL/a
339, 810GL/30a
MurrayDarling Basin
Not known
>1, 832GL/a
54.960GL/30a
CondamineBalonne4
na
1, 305GL/a
722GL/a
21.660GL/30a
na
CondamineBalonne
Not known
>160 GL/a
4.800GL/30a
SOURCE: 1. Hillier and Frost, (2002); 2. Kellett et al (2003); 3. GABCC Annual Report 2008/9. 4. CSIRO 2008a;
CSIRO 2008c.
These figures are even more concerning at the regional level. For example,
the current average annual surface water resource in the Condamine-Balonne
region is around 1, 305GL/year (which is 8.5% of the total runoff in the MDB)
(CSIRO 2008a). The current level of use for the region is extremely high –
722GL/year of the average available surface water is diverted for use (which
equates to 55% of the region’s available resource) (CSIRO 2008a).
Monitored groundwater extraction in the Condamine-Balonne region for
2004/05 is 160 GL/year and 97% of this occurs in the Upper Condamine
catchment (CSIRO 2008a). This volume is primarily based on metered use,
and the total monitored and unmonitored groundwater use in the Upper
Condamine is thought to be around 25% higher (CSIRO 2008a). Current
extraction is already ‘unsustainable’ in 15 of the 22 groundwater management
units (GMUs) in the region, where extraction in these GMUs is more than
double the average potential rainfall recharge. Extraction in six of these
GMUs is more than five times the average potential rainfall recharge. In the
area of the Upper Condamine that is modelled for groundwater, extraction
(currently 47GL/year) exceeds recharge by 38% and recharge is historically
exceeded in more than 90 percent of years (CSIRO 2008a).
According to CSIRO (2008a), if groundwater extraction in the Upper
Condamine sub-catchment were allowed to increase to the current entitlement
levels, the system would be severely over-allocated and additional streamflow
impacts would occur. Furthermore, according to both Hillier (2010) and
CSIRO (2008), the GAB Alluvial GMU is connected to the surface water
system, and forseeable increases in extraction (not including CSG water
extraction) will reduce streamflow by 5 to 6GL/year.
22
Qld GAB Bowen and Surat Basin Annual Extraction / Use Levels
Qld GAB
Groundwater
Management
Units
S&D
Entitlement
(excl S&D)
General
Reserve2
(GL/year)
(GL/year)
(GL/year)
Total
(excl.
general
reserve)1
(GL/year)
Surat 1 – 8
47.1
19.8
5
66.9
Surat North 1 – 4
16.4
2.5
0.2
18.9
Surat East 1 – 4
10.3
15.5
2
25.8
73.8
37.8
7.2
111.6
3.4
0.4
0
3.8
Surat Basin
Mimosa 1
Bowen Basin
Total
77.2
38.2
7.2
Estimated
CSG
extraction*
(proponents)
(GL/year)
467 to 914
(61)
3.8
1.8 to 3.4
(3.3)
115.4
468.8 to
917.4
(64.3)
* Assumes a 30 year production period
SOURCE:
1.
Qld DERM (2005). Hydrogeological Framework Report for the Great Artesian Basin Water Resource Plan Area
(Version 1.0). Report prepared by the Queensland Department of Natural Resources and Mines, Brisbane
[www.derm.qld.gov.au/wrp/gab.html#maps].
2.
Qld GAB Water Sharing Plan, 2006. (Note the explanatory notes indicate and additional 10GL in the state
reserve).
23
Appendix 3 – Derivation of the amount of groundwater
to be co-produced
Overview
Original estimates of how much groundwater could be produced was derived
from a limited amount of published information.
The Queensland Government Mining Journal (2008) estimated that 100ML of
groundwater would be produced for every PetaJoule (PJ) of energy. The
Journal estimated that there was 250,000PJ in the Surat and Bowen Basin
giving a groundwater production of 25,000GL. As 69% of the resource is
estimated to be in the Surat Basin this would equate to a groundwater volume
of approximately 17,300GL.
The second estimate was derived for the information contained in the yet to
be published draft Waterlines Report2. This report, using information from
QGC, indicates that groundwater production rates in their wells range from
0.4-0.8ML/d before decreasing to a rate of about 0.1Ml/d over six months to a
few years. The current estimates from the proponents (and AP LNG) are that
there will be approximately 18,500 production bores. Simply assuming that
number of bores pumping at 0.6ML/d for 12 months, and then at 0.1ML/d for
14 years (15 years is the normal production life for a bore), this would result in
a groundwater production of approximately 13,500GL.
In the Gas Today Magazine (May 2009) Robert Caine, Origin Energy Senior
Engineer Water Management, is quoted as saying that bores will produced
between 0.1ML/day to 0.8ML/day. For a production life of 15 years and
18,500 bores for 0.1ML/day this results in a figure of approximately 10,000GL
and for 0.8ML/day 81,000GL.
All of these published estimates result in considerably more groundwater
being produced than that estimated by the proponents (and AP LNG) of
1,819GL.
Walloon Coal Measures
The majority of the groundwater to be co-produced, as part of the CSG
developments will come from the Walloon Coal Measures. The groundwater
to be co-produced will be that which forms the pressure head, or the elastic
storage. The amount of groundwater that can be produced due to this
drawdown in pressure (elastic storage), can be measured through the
equation:
Es = Ss x Va x H1-H2
2010, On-Shore Co-Produced Water – Discussion Paper, Waterlines Report,
National Water Commission, Canberra (p7 of the yet to be published report).
2[DRAFT]
24
Where Es is the elastic storage; Ss is the specific storage; Va is the volume of
the aquifer and H1-H2 is the difference in pressure head.
Specific storage was either provided directly in, or can be calculated from the
storativity (storage co-efficient) values provided in the EIS documentation by
the equation:
Ss = S/b
Where S is the storativity and b is the thickness of the aquifer (in this case the
amount of the aquifer to be perforated). From discussions with Przemyslaw
Nalecki (Santos) up to 30m of coal seams would be perforated and so a
thickness of 90m should be used.
From the data provided in the EIS’ this results in a range of Specific Storage
values from 10-5 to 10-7. Based on the expected drawdowns from the
proponents (and AP LNG) a H1-H2 value of 400m was used as an indicative
levels as the drawdown in some areas will be greater and in some areas
smaller. The thickness of the Walloon Coal Measures is 300m and indicative
areas were calculated for the QGC, Santos, AP LNG and cumulative areas:
o Santos 4,900km2
o QCG and AP LNG 3,900km2
o Cumulative area (main Walloon CSM Fairway) 19,125km2.
Using the numbers the amount of Elastic Storage was calculated for each
proponent and the cumulative area:
QCG
Santos
AP LNG
Cumulative
Specific Storage 10-5
Specific Storage 10-6
Specific Storage 10-7
2,340GL
5,880GL
2,340GL
22,950GL
234GL
588GL
234GL
2,295GL
23.4GL
58.8GL
23.4GL
229.5GL
As a sensitivity analysis 3 other options were considered using a variable
ranges of Specific Storage:
o Option A: 20% - 10-5; 60% - 10-6; 20% - 10-7
o
Option B: 60% - 10-5; 20% - 10-6; 20% - 10-7
o Option C: 20% - 10-5; 20% - 10-6; 60% - 10-7.
Using the parameters described above this gives the following:
QCG
Santos
AP LNG
Cumulative
Option A
613GL
1,540GL
613GL
6,013GL
Option B
1,455GL
3,657GL
1,455GL
14,275GL
Option C
529GL
1,329GL
529GL
5,187GL
25
To further understand the amount of groundwater to be produced, analysis of
the data in the QCG EIS to calculate the Elastic Storage was also done. ( As
noted in the report Santos had described there modelling in the EIS as
‘inadequate’ and hence a similar assessment to the QGC data was not done
for the Santos area). This analysis was done for the 3 development areas.
From the QGC modelling numbers Specific Storage values of 1x10 -5 to 1x10-6
can be derived and the area was the modelled depressurisation area.
Development Area
Area
WCM
H1thickness H2
(m)
North West
500km2 300
518
Volume
using
Specific
Storage
10-6
388.5GL
Volume
using
Specific
Storage
10-5
3885GL
Central
South East
500km2 300
500km2 300
249
410
186.8GL 1867GL
307.5GL 3075GL
This would indicate a total volume to be extracted of 883GL - 8,8270GL The
predicted volume from QCG is 887GL. Hence it can be interpreted that the
production numbers stated by QGC present a low side, or conservative,
estimate of the amount of water produced. Importantly, this analysis did not
include any production from the Springbok Sandstone. Given that QGC notes
that the two units are in hydraulic connection and the pressure head will be
drawn down to below the base of the Springbok Sandstone (as per their
documentation), the volume of water to be produced will be considerably
larger than that predicted by QCG. (Note this number does not include water
produced or ‘lost’ from other formations e.g. Hutton Sandstone).
Other Formations
A similar analysis was performed for other formations as per the methodology
detailed in the previous section and only the cumulative numbers are
presented here. Two drawdowns (H1-H2) were used based on the minimum
and maximum drawdowns (as applicable) listed by the proponents.
Gubberamunda Sandstone
H1-H2
(0.7m)
H1-H2
(13m)
Specific
Storage 10-5
Specific
Storage 10-6
Specific
Storage 10-7
Option A
Option B
Option
C
11.3GL
1.1GL
0.1GL
2.9GL
7.0GL
2.5GL
208.9GL
20.9GL
2.1GL
54.7GL 129.9GL 47.2GL
26
Hutton Sandstone
H1-H2
(2.5m)
H1-H2
(10m)
Specific
Storage 10-5
Specific
Storage 10-6
Specific
Storage 10-7
Option A
Option B
Option
C
110GL
11GL
1.1GL
28.8GL
68.4GL
24.9GL
439.9GL
44.0GL
4.4GL
115.2GL 273.6GL 99.4GL
Using the QGC figures detailed in their modelling and doing a similar analysis
as performed for the Walloon Coal Measures a range of 0-431GL is derived.
Precipice Sandstone
H1-H2
(1.0m)
Specific
Storage 10-5
Specific
Storage 10-6
Specific
Storage 10-7
Option A
Option B
Option
C
12.0GL
1.2GL
0.1GL
3.2GL
7.5GL
2.7GL
Using the QGC figures used in their modelling and doing a similar analysis as
performed for the Walloon Coal Measures a range of 0-252GL is derived.
Springbok Sandstone
Both proponents (and AP LNG) agree that the WCM are in hydraulic
connection with the Springbok Sandstone, though they suggest the degree of
connectivity is variable. This suggestion is somewhat of a misnomer. Where
there is a connection, groundwater from the Springbok Sandstone will flow
directly into the WCM and these areas of influence will spread out across the
Springbok Sandstone and become interconnected; increasing the loss of
groundwater. As the lowering of pressure in the WCM is to be below the base
of the Springbok Sandstone, the Springbok Sandstone (and the top part of the
WCM) will be dewatered.
Once the pressure drawdown in the Walloon Coal Measures reaches the top
of the Springbok Sandstone the ongoing extraction will change this aquifer
from a confined to an unconfined system. To calculate the amount of
groundwater a different equation is needed:
Vw = S x Area x H1-H2
Where Vw is the volume of water; S is the storativity and H1-H2 is the amount
of drawdown in the aquifer.
The areas from the previous analysis were used and three H1-H2 values were
used to reflect the variability in thickness of the Springbok Sandstone. The
storativity values are those supplied by the proponents (and AP LNG). The
value of 10-3 was used as an ‘average’ between the listed values. It is
interesting to note the difference in values between QGC and AP LNG even
though they are largely in the same area.
27
Storativity 10-2
Storativity 10-3
Storativity 10-4
QGC
40
70
110
7.8GL
13.65GL
21.45GL
Santos
40
70
110
19.6GL
34.3GL
53.9GL
AP LNG
40
70
110
780GL
1,365GL
2,145GL
Cumulative
40
70
110
7,650GL
13,387GL
21,037GL
765GL
1,339GL
2,104GL
76GL
134GL
210GL
Using the QGC figures used in their modelling and doing a similar analysis to
that done above a range of 5.9 to 86.7GL is calculated. This higher figure is
well above the maximum calculated and shown in the table above.
Summary
The maximum range for cumulative co-produced groundwater from all
formations based on this analysis is 307 to 44,647GL. The published data
would indicate a range of 13,500 to 81,000GL. The proponents (and AP
LNG) predict that 1,819GL of groundwater will be produced which appears to
be a conservative estimate. The sheer varability in volumes that can be
calculated in the numbers provided by QGC alone increases the level of
uncertainty as to how much groundwater will be produced. Hence, on balance
of probability, it is likely that more groundwater will be produced than that
predicted by the proponents and AP LNG.
Bandanna Formation
The majority of water that will be produced in the Bowen Basin will be from the
Bandanna Formation. To estimate the amount of water to be produced the
following equation, as for the Surat Basin, was used:
Es = Ss x Va x H1-H2
Where Es is the elastic storage; Ss is the specific storage; Va is the volume of
the aquifer and H1-H2 is the difference in pressure head.
Calculations were only made for the Fairview Field area. An estimated area of
50km by 50km was used and two estimated formation thicknesses 134m and
28
250m to reflect variability. A drawdown of 300m was used based on the
information provided by Santos (noting the modelling for this area was
described as ‘inadequate’ by Santos staff).
A sensitivity analysis was also performed to test various levels of specific
storage.
134m
250m
Specific
Storage 10-7
Specific
Storage 10-6
Option A
Option B
Option
C
10.05GL
18.8GL
100.5GL
187.5GL
55.3GL 77.9GL 32.7GL
103.1GL 145.3GL 60.9GL
Option A: 50% - 10-7; 50% - 10-6
Option B: 75% - 10-7; 25% - 10-6
Option C: 25% - 10-7; 75% - 10-6
Precipice Sandstone
No analysis was performed for the Precipice Sandstone due to the modelling
deficiencies noted previously. Further advice will be provided as to potential
impacts on this formation.
29
Appendix 4 – Recommendations from the 255A[A]
inquiry into ‘The impacts of mining in the Murray
Darling Basin’
On 12 August 2009, the tasked the Environment, Communications, and the Arts
References Committee to hold an inquiry into ‘The impacts of mining in the Murray
Darling Basin’.
On 4 December 2009 the Committee delivered the following recommendations:
Recommendation 1
The committee recommends that all governments support the Namoi Catchment
Water Study and not take further decisions in relation to the licensing of mining and
extractive industries in the Namoi catchment until that study is completed and
publicly released.
Recommendation 2
The committee recommends that, as a matter of priority and preferably prior to the
release of future Mineral Exploration Licences, state governments establish regional
water plans in areas potentially subject to mining or extractive industry operations.
Recommendation 3
The committee recommends that the Commonwealth Government:
• investigate the scope of Section 255A of the Water Act 2007 to determine whether it
applies to groundwater resources located in ridge country. If this is not the case, the
committee recommends that the Commonwealth Government amend Section 255A
to include groundwater resources on all land types.
• Work with the states to ensure the prohibition of the licensing of mining or extractive
industries in the event that a study conducted under section 255A indicates that
development would have adverse impacts on groundwater resources and the
environment.
Recommendation 4
The committee, noting extensive planning and research already being undertaken
including the National Water Initiative, the Basin Plan, regional water plans and other
studies currently underway,
• Urges all governments to maximise use of information and data gleaned from
planning and research activities to ensure that coordinated analysis of regional water
plans takes place, so as to better understand the cumulative impacts of mining in the
Murray-Darling Basin; and
• Recommends that the Commonwealth Government works to ensure the prevention
of new mines or extractive industries in the Murray Darling Basin if their impacts on
water resources are inconsistent with the Basin Plan.
Source: Environment, Communications, and the Arts References Committee Report,
‘The impacts of mining in the Murray Darling Basin’
http://www.aph.gov.au/senate/committee/eca_ctte/mining_mdb/report/report.pdf,
accessed 10/09/2010
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