Expert Witness Report: Water Cycle Impact Assessment of Changing to
Biomass Fuel at Redbank Power Station
Report Prepared for: Verdant Earth Technologies Ltd under
instructions from Mr Ross Fox, Fishburn Watson O’Brien
Lawyers.
21 October, 2021 Project No. 276
Prepared by: Sustainability Workshop Ltd
Head Office Suite 1/124 Station Street Blackheath NSW 2785
[email protected] M: 0468 423 299
www.sustainabilityworkshop.com
Document Information Project title Expert Witness Report – Water
Cycle Impact Assessment of Changing
to Biomass Fuel at Redbank Power Station
Document title
Expert Witness Report: Water Cycle Impact Assessment of Changing to
Biomass Fuel at Redbank Power Station
Project number
Name Signature Issue: Date
Checked by
Filename S:\Projects\276 Redbank Power Station - Biomass
Conversion\Reporting\Expert Witness Planning Report - Water Cycle
Management 211021.docx
Document History
Issue to:
Commercial in Confidence
All intellectual property rights, including copyright, in drawings
or documents developed and created by The Sustainability Workshop
Ltd remain the property of that company. Any use made of any such
information without the prior written approval of The
Sustainability Workshop Ltd will constitute an infringement of the
rights of that company which reserves all legal rights and remedies
in respect of any such infringement.
The information, including the intellectual property, contained in
this report is confidential and proprietary to The Sustainability
Workshop Ltd. It may only be used by the person to whom it is
provided for the stated purpose for which it is provided, and must
not be imparted to any third person without the prior written
approval of Sustainability Workshop Ltd. Sustainability Workshop
Ltd reserves all legal rights and remedies in relation to any
infringement of its rights in respect of its confidential
information.
© 2021 The Sustainability Workshop Ltd
Disclaimer
This report was prepared by Sustainability Workshop Ltd for its
clients' purposes only. The contents of this report are provided
expressly for the named client for its own use. No responsibility
is accepted for the use of or reliance upon this report in whole or
in part by any third party.
This report is prepared with information supplied by the client and
possibly other stakeholders. While care is taken to ensure the
veracity of information sources, no responsibility is accepted for
information that is withheld, incorrect or that is inaccurate. This
report has been compiled at the level of detail specified in the
report and no responsibility is accepted for interpretations made
at more detailed levels than so indicated.
iii
.EXECUTIVE SUMMARY 1. The likelihood of both the chronic
(cumulative) and acute (toxic) aquatic
ecosystem impacts from the proposed development has been
assessed.
2. Based on a 40 year, 6 minute time step, water balance model of
the site, if
recommendations in this report are adopted, the site is predicted
to discharge
less frequently than once every 10 years.
3. This occurs because the power station consumes 3,208 ML/a of raw
water,
including any site generated stormwater, while producing 28.7 ML/a
of runoff.
4. The volume of stormwater runoff, in a typical year, is less than
0.1% of the total
demand for raw water.
5. 99.7% of stormwater runoff is reused on the site and is lost as
steam.
6. Because predicted off-site discharge would occur less than once
every 10 years,
chronic aquatic ecosystem impacts will not occur.
7. During any rare discharge from the site, which is predicted to
occur only during
extreme events such as the Pasha Bulker storm event, there would be
a 250-fold
level of dilution of off-site discharges as they blend with
catchment flows.
8. Discharge from the site is predicted to occur less than 0.0016%
of the time.
9. During extreme flood events, ambient or environmental water
quality is
typically extremely poor. Especially so in the Dights Creek
catchment which has
been highly disturbed by both mining and agriculture.
10. On this basis, it is highly unlikely that there will be any
acute aquatic ecosystem
impacts.
11. I therefore conclude that:
a. The proposal would comply with applicable guidelines being the
NSW State
Government’s Organics and Composting Guidelines which set a
discharge
frequency for the site, from any leachate dam, of less than 1 in 10
years.
b. That the proposal is not likely to have any adverse aquatic
ecosystem
impacts.
c. The proposal would be likely to comply with typical licence
limits for an
organics or composting facility.
2.0 INVESTIGATION
.................................................................
3
5.1. Existing water cycle management at Redbank Power station
...................... 8
5.1.1. Raw Water Demand
.....................................................................................
8
5.1.2. Raw Water Pond Water Level and Spill Management
.................................. 9
5.2. Stockpile Area
..............................................................................................
9
5.3. Dights Creek
...............................................................................................
10
5.5. Existing Water Quality Controls
..................................................................13
5.5.1. Drive in Sediment Traps
..............................................................................13
5.5.2. Water Quality Pond
....................................................................................
15
5.5.3. Concrete Channel and Screen
....................................................................
16
5.5.4. Raw Water Pond
..........................................................................................
17
5.6. On-Site Maintenance
.................................................................................
19
6.0 PROPOSED DEVELOPMENT
............................................. 20
6.2. Proposed Woody Biomass Fuel
..................................................................
20
7.0 PREDICTING RUNOFF QUANTITY
..................................... 22
7.1. A predictive water balance model
..............................................................
22
v
7.3. Modelled Land Uses – hydrologic parameters
............................................ 26
7.4. Modelled land uses adopted EMCs
.............................................................
27
7.5. Modelling the water quality pond and raw water pond
.............................. 28
8.0 RESULTS & PREDICTED COMPLIANCE
.............................. 30
8.1. Frequency of discharge
..............................................................................
30
8.2. Water quality impacts
................................................................................
30
8.3. Water quality discharge during extreme events
..........................................31
8.4. Predicted compliance with applicable development standards
.................. 32
9.0 MODELLING THE POST DEVELOPMENT SITE ....................
33
9.1. What are the differences between pre and post development
models? ..... 33
9.2. Predicted maximum indicator pollutant concentrations
............................ 34
10.0 WATER POLLUTION RISK
................................................. 35
10.1. Risk of off-site water quality impacts
......................................................... 35
10.2. Acute risk of water pollution
.......................................................................
35
11.0
RECOMMENDATIONS.......................................................
36
Sustainability Workshop
1.1. Background 12. Sustainability Workshop was engaged by Verdant
Earth Technologies Ltd through
Fishburn Watson O’Brien (FWO) Lawyers to prepare an expert report
in relation to a
class 1 appeal which was filed in the Land and Environment Court on
7th May 2021,
appealing against deemed refusal of an application to modify the
development
consent of the Redbank Power Station.
13. Verdant Earth Technologies Ltd is the development
proponent.
14. FWO Lawyers have given instructions to Mark Liebman, the author
of this report, to
provide an expert opinion with respect to the predicted ecological
impacts of the
proposed development on receiving waters. The key question being
“what are the
likely aquatic ecosystem impacts of the proposal and what, if any,
modifications are
required to the existing water cycle management at Redbank Power
Station to
mitigate any additional impacts”.
15. It is noted that previous information was provided by RGH
Consulting. It is
acknowledged that the previous report did not contain sufficient
information to
enable Council and the EPA to determine the application with
respect to the potential
to cause any off-site aquatic ecosystem impacts.
16. Sustainability Workshop Ltd has since been commissioned to
assess the impacts of
the proposal on water quality. It is requested that previous
information provided by
RGH be disregarded.
17. A Curriculum Vitae is included in Appendix A of this
report.
18. The opinion in this report is based on over 24 years
professional civil and
environmental engineering experience with a specialist focus on
stormwater quality
management, water policy, pollution prevention and
eco-hydrology.
1.2. Instructions 19. FWO Lawyers have given instructions to Mark
Liebman, the author of this report, to
provide his opinion with respect to the potential environmental
impacts of the
proposed development on receiving waters and to identify any
changes to the existing
water cycle management operations on the site to mitigate against
any adverse
impacts.
Sustainability Workshop
2
1.3. Expert Witness Code of Conduct 21. I have read the Expert
Witness Code of Conduct, and agree to be bound by it, at
schedule 7 of the Uniform Civil Procedure Rules 2005 (NSW) (the
“Code of Conduct”)
and confirm that to the best of my knowledge this report has been
prepared in
accordance with the Expert Witness Code of Conduct.
22. At this point I have considered all information available and
enquired with respect to
the development proposal. I have requested information from Verdant
Earth
Technologies Ltd and inspected the site. I have prepared a revised
water balance
model for the proposed development, and I am able to make an
independent
determination on the potential of the proposal to cause impacts on
the receiving
waters.
2.0 INVESTIGATION
2.1. Site Investigation 23. On the 6th of October, 2021, Mark
Liebman, CPEng, MIEAust, attended the Redbank
Power Station with Mr Costa Tsiolkas, General Manager, and Mr Owen
Hassall,
Recommissioning and Engineering Manager.
24. Following the site visit supplementary information has been
provided.
25. Site observations are reflected in Figure 1.
26. During the site investigation the following was observed:
a. The proposed stockpile area including existing subsoil drainage
beneath it.
Subsoil drains were located at regular intervals underneath the
stockpile area
and drain directly into a concrete lined channel. Subsoil drains
are embedded
in free draining gravel.
b. The capacity to provide a 2m wide grassed vegetated buffer strip
between
the stockpile truck access route and the edge of a concrete lined
channel
which collects runoff from the stockpile area.
c. A concrete lined channel which would intercept runoff from the
stockpile
area and subsoil drains under the stockpile and direct it to a
sediment and oil
trap and then into a water quality pond.
d. The water quality pond was observed to be in healthy condition,
with an
internal baffle to ensure no short circuiting of flows.
e. The pond had both emergent and submerged vegetation. The pond
had
many of the attributes of a well maintained and healthy constructed
wetland.
f. Additional drainage features including surface drainage and a
piped network
that would divert runoff from the boiler island to the water
quality pond –
also after first being treated in a sediment and oil trap.
g. Numerous bunded areas on the site where chemicals are stored and
where
wastewater is treated. Bunds are used to manage acute toxicity
risks
emanating from an accidental spill of a chemical. I observed all
bunded areas
where clean, visibly free of pollution and well maintained with all
bunds
appearing to maintain their structural and liquid retention
integrity.
h. The lower, more northern part of the site which includes an
administration
building, wastewater treatment infrastructure, water cooling
structure, joins
stormwater runoff from the water quality pond and is conveyed in a
concrete
channel to a welded plastic (HDPE) lined, raw water storage
pond.
Sustainability Workshop
4
i. There was an additional screen and oil baffle and water quality
monitoring
point upstream of the entry into the raw water storage. I observed
the raw
water storage to be about 6 to 7m deep by visual assessment. The
raw water
storage was close to empty at the time.
j. The wastewater storage, being much larger to the east of the raw
water
storage. It was also lined with a welded waterproof plastic
liner.
k. The mechanism by which the raw water storage overflows or spills
– this is by
way of a weir close to the site entry gate. The raw water storage
overflows
into a swale which heads west and then joins Dights Creek.
l. Dights Creek has been diverted around the operational area of
the site and
this was approved under the previous development application. Where
the
creek was diverted it remains in a stable well vegetated state,
free from
visible erosion and without obvious weed infestation.
m. I observed Dights Creek downstream of the site and just after it
flows under
Long Point Road. The creek appears to be in a well vegetated,
stable state
with numerous riparian trees and grasses.
Sustainability Workshop
60 ML wastewater storage
Stockpile area
Concrete Channel with subsoil drains flows in from stockpile
area
Concrete Channel collecting runoff from area south of admin
building
Admin building
Water pumped into the raw storage from Hunter River
Dights Creek
Cooling Tower
Sustainability Workshop
3.0 DOCUMENTS 27. I have relied on the following documents:
a) Expert Witness Code of Conduct.
b) Amended Statement of Facts and Contentions from Council dated 15
September
2021.
c) Redbank Power Station – Description of Proposed Modifications
for Conversation to
Fire Biomass Fuels, B&PPS Report C12198-01, dated 20 October
2021.
d) Operational Traffic Management Plan (Redbank Power Station),
Ason Group, dated
20 October 2021.
e) Transport Assessment (Redbank Power Station), Ason Group dated
20 October
2021.
f) Site plan by Alstom numbered as ‘80034-001-M-GA-000-5001
A0’.
g) Site plan by Alstom numbered and ‘80034-025-M-GA-000-9176
A1’.
h) Concept study by B&PPS titled ‘Biomass Handling Plant
Concept Study B&PPS
Report (C12156-03)’, by B&PPS, Rev 4 dated 18 June 2021.
i) Redbank QA/QC Supply Chain and Material Handling dated 30 July
2021.
j) Water Treatment Plant Process Flow Balance Diagram prepared by
ABB and US
Filters numbered as 80034-007-P-P1-063-8551.
k) 128 MW Powerplant, Bulk Earthworks and Drainage Sheet 1 of 2, by
ABB, Drawing
number 8034-002-C-BP-119-6012 Revision 3 Reissued for
Construction.
l) Hunter River Salinity Trading Scheme Redbank Power Station
Discharge Volumes
and Salt Loads from 2001 to 2015/2016 provided by the HSE
Manager.
Sustainability Workshop
4.0 ADDITIONAL INFORMATION REQUIRED
28. I have sufficient information with which to make an informed
decision with respect to
the potential aquatic ecosystem impacts of the proposed
application.
Sustainability Workshop
5.1. Existing water cycle management at Redbank Power station
5.1.1. Raw Water Demand 29. A water balance for the site has been
included in Appendix C.
30. Raw water is hereafter defined as either water extracted from
the Hunter River or
stormwater runoff from the power station site which drains into the
raw water
storage pond shown in Figure 1.
31. Broadly speaking, the power station combusts fuel to generate
heat. The heat is
used to boil water and generate steam which drives turbines to
create electricity.
32. A significant volume of raw water is used to cool the steam to
condense it. The
steam is ultra-high-quality demineralised water, and this form of
water is simply
recycled as it is expensive to make demineralised water.
33. Raw water is used to cool the steam once it has passed through
the turbine without
coming into direct contact with the steam via a heat exchanger. As
a result, a
significant volume of raw water is lost, through evaporation in the
process as it is
used to cool and condense the steam.
34. Discussions with the General Manager and site engineers and
consistent with the
water balance for the site (Appendix C) the mean demand for raw
water is 366.3 kL
per hour to cool the steam. The 90th percentile demand increases
368.1 kL/hour, and
the maximum demand is 380.2 kL/hour. Approximately 39.7 kL/hour is
returned to
the raw pond giving a mean hourly withdrawal rate of 401.7 kL/hour
from the pond.
Refer to Point 3 on the diagram in Appendix C.
35. We note the water balance in Appendix C shows the inclusion of
ash slurry
transportation water into the raw water pond. It is understood that
this does not
occur.
36. As a base load power station, it is intended to operate
24-hours, 365 days per year.
Planned shutdowns to carry out maintenance would occur
periodically.
37. It is therefore appropriate to extrapolate mean hourly water
consumption to derive a
daily or yearly demand. Daily demand for raw water is 24 X 366.3 =
8,791.2kl/day or
8.791 ML/day. Annual demand is 3,200 ML/year.
38. Verdant Earth Technologies Ltd has a water access licence to
extract up to 3,300
ML/year of raw water from the Hunter River.
Sustainability Workshop
9
39. The raw water storage pond has a volume of 6,000 cubic metres
which equates to
6ML.
40. The raw water storage is filled with water extracted from the
Hunter River and is
operated so that there is always a nominal level of 4ML of raw
water available in the
storage.
5.1.2. Raw Water Pond Water Level and Spill Management
41. The site is operated so that 4 ML metres of raw water is
available to provide
nominally 12 hours water supply to cover the risk of a power outage
or failure at the
river side pumps.
42. The raw water storage is then operated with 2 ML headroom.
Headroom is defined
as air space above the operating water level to temporarily store
stormwater runoff
from the site to prevent an off-site discharge.
43. A safe work Procedure (SWP-10-0004) has been adopted which
describes this
operational procedure. It is broadly summarised as follows:
44. The site operators continually review Bureau of Meteorology
Forecasts, and if rain is
predicted they prepare to turn off the pumps which they can do
remotely from the
power station site.
45. Once rain commences and stormwater runoff from the site starts
entering the pond
the pumps are turned off. Flow entering the pond is monitored both
visually and
remotely from a water level and conductivity gauge installed at the
entry point to
the pond.
46. Site operators then monitor the event and pumping recommences
once the storm
event is over and flow and water level in the raw water pond are
returned to the 4ML
typical operating level.
47. In the event of a spill from the pond, site operators are
required to collect water
quality samples hourly and get them tested to comply with the
licence conditions on
the site.
5.2. Stockpile Area 48. The existing stockpile area is well drained
and underlain by subsoil drainage lines
which discharge directly to the drainage channel. This will prevent
any pooling of
leachate at the base of the stockpile and protect
groundwater.
49. The area available for storage is about 0.57 hectares and is
bound to the south and
west by an earth mound and to the north by the concrete
channel.
Sustainability Workshop
10
50. The stockpile area is limited by the reach of two telehandlers
which pile the fuel after
unloading from trucks.
51. The stockpile area is serviced by several spray nozzles which
are used for dust
suppression across the area. Water is drawn from the water quality
pond and
pumped into a holding tank prior to spraying.
52. Currently, there is a small volume of coal stored in this
area.
53. During operations, the area is serviced by two large conveyors.
One would be used
to accept coal onto the site and the other is used to feed coal
into the power station
process.
54. There would be some minor modifications to the fuel feed
process which do not
have any predicted water quality impacts. This includes minor
modifications to the
conveyor system to feed biomass into the power plant.
5.3. Dights Creek 55. Redbank Power Station discharges into Dights
Creek. The creek appears to be in a
stable and well vegetated state downstream of the point of
discharge. The previous
diversion works have successfully created a modified but otherwise
natural and
stable riparian environment.
56. The upstream catchment has been severely modified by mining as
shown in Figure
2. Approximately two thirds of the catchment was disconnected due
to mining and
approximately the last 1/6th of the catchment is fully cleared for
farming. Any
remnant aquatic ecosystems within this catchment would be highly
disturbed and
severely modified by past development.
Sustainability Workshop
5.4. Wastewater Discharge to the Hunter River
57. The Redbank site has a licence condition requiring it to report
activities arising from
its participation in the Hunter River Salinity Trading
Scheme.
58. The scheme objectives are to ensure salinity levels in the
river are reduced at the
lowest community cost and the scheme is open to any participant who
becomes a
creditor.
59. The source of salt produced in this industrial process
originates from salty water
extracted from the river.
60. Wastewater is generated at a rate of 6.6 kL/hour (point 29 on
the diagram in
Appendix C) and comes from reject water from the reverse osmosis
plant on the site.
Sustainability Workshop
12
Influent to the reverse osmosis plant has been first clarified and
filtered to remove
solids and chemicals that can be precipitated.
61. There are no anti-scaling agents used to clean the boiler which
would then be
present in wastewater. Because ultra-high quality deionised water
is made on-site
using an RO plant, magnetite is added to the demineralised water to
ensure it
doesn’t leach metals from the boiler.
62. Therefore, the wastewater contains only brine from the
treatment process. All
solids, metals and other contaminants are removed from the waste
stream by
thickening and pressing and then disposed of lawfully. Analysis of
the pressed solids
indicates it would comply with a waste recovery order to allow the
material to be
reused as a soil conditioner, i.e., it has relatively low levels of
contaminants that
comply with current resource recovery orders.
63. The wastewater storage fluctuates over time as rain falls on
the storage and water
evaporates. The more it rains the more the storage level builds up
and vice versa.
64. From time to time the opportunity to empty the storage of its
salty water is taken
when flows increase in the Hunter River and credit is not needed to
discharge the
water.
65. Occasionally credit is purchased, and water is discharged using
the credits when flow
rates permit.
66. Table 1 showing discharges to the Hunter River under the
Scheme
FINANCIAL DISCHARGE SALT LOAD
2001 (CY) 50.6 238.1
67. The wastewater (brine) discharged from the site is licensed. It
is dosed to adjust its
pH prior to any discharge.
68. Discharging wastewater to the river is not an alternative
method of disposing of
contaminated stormwater from the site. While stormwater
contaminants are
removed from the raw water storage pond and noting some
contaminants would
originate on the site, we reiterate that all non-salt contaminants
are removed from
the process prior to treatment in the reverse osmosis (RO) plants
and they are not
found in the RO reject water, i.e., brine, which is discharged from
the site.
69. The source of salt in the water is largely from elevated salt
levels present in raw
water harvested from the Hunter River. An insignificant mass of
salt would arise
from treating runoff from the site itself where salt present is the
result of
atmospheric deposition.
70. The trading scheme is understood to be highly successful in
reducing the salinity of
the river.
5.5. Existing Water Quality Controls
5.5.1. Drive in Sediment Traps 71. Drive in sediment and floating
oil traps are present in two locations upstream of the
water quality pond. These are a simple but effective method of
removing coarse
sediment and floating oil and grease. They are cleaned periodically
by bob cat.
Sustainability Workshop
14
Plate 1 Showing drive sediment trap accepting runoff from boiler
island catchment.
Plate 2 Drive in sediment trap at end of stockpile channel
Sustainability Workshop
15
5.5.2. Water Quality Pond 72. The water quality pond is a textbook
best management practice which has a surface
area of about 1,600 m2 and an average depth estimated to be at
least 1m. It has
peripheral macrophytes, a baffle wall to stop short circuiting of
the catchment which
has an incoming stormwater pipe close to the outlet.
73. It has both emergent, submerged and floating aquatic
vegetation.
74. The water quality pond accepts runoff from the stockpile
storage area and the boiler
island. This would be the dirtiest parts of the existing and
proposed operation with
all other elements being bunded and separated from stormwater to
facilitate only
controlled discharges.
75. The pond is an effective method to further settle medium to
fine grained sediment
and for removal of dissolved nutrients including ammonia, nitrate
and nitrite and
orthophosphate.
76. The pond has been cleaned out periodically to remove
accumulated sediment from
its base.
77. Water is removed from this pond for dust suppression of the
stockpile area however
this pond has reportedly never run dry. Demands for water for dust
suppression
were described as modest.
Plate 3 Showing water quality pond with steel baffle wall to stop
short circuiting
Sustainability Workshop
16
Plate 4 Water quality pond – looking north west across the
pond.
5.5.3. Concrete Channel and Screen 78. There is a simple and
effective gross pollutant screen upstream of the raw water
pond.
79. The screen traps gross pollutants and some coarse
sediment.
Sustainability Workshop
17
Plate 5 Gross Pollutant Screen in channel upstream of raw water
storage
5.5.4. Raw Water Pond 80. The raw water pond is the final element
of the treatment train on this site.
81. It functions as a large sediment basin and water storage
pond.
82. It stores 6 ML of water, for the purposes of this report, 4 ML
of which is considered
dead storage as it is typically filled with raw water from Hunter
River.
83. Prior to entry into the raw water pond there is a final baffled
sediment and oil trap.
84. Water is extracted from the Hunter River and piped into the
pond.
85. The pond receives stormwater runoff from the whole site
including adjacent roads.
There is a small area of the adjacent road which bypasses the
pond.
86. There is flow monitoring the salinity of inflow to the pond
with the probe suspended
from the gantry bridge visible in Plate 6. The water level is also
monitored.
Sustainability Workshop
18
Plate 6 baffled sediment and oil trap adjacent to raw water
storage
Plate 7 Raw water pond showing combined inlet/spillway at left and
raw water pipes from Hunter River with plastic liner visible.
Sustainability Workshop
19
5.6. On-Site Maintenance 87. Maintenance of VET’s vehicle fleet
occurs off site and no on-site impacts would
occur as a result.
88. The most common maintenance activity on-site is the use of
grease and oil guns to
lubricate pumps, valves and motors. Oil is stored in a bunded area,
containers are
filled in the bunded area and then taken to where they are
needed.
89. Staff are trained to use spill kits.
90. Transformers, diesel storage, diesel fuel pump, any hazardous
chemicals etc are all
stored in bunded areas to contain at least 110% of the volume of
the largest tank in
accordance with relevant Australian Standards.
91. A pre-purchase due diligence site contamination assessment
revealed a strong
history of operational environmental diligence and low risk
acquisition for VET Ltd.
Sustainability Workshop
6.0 PROPOSED DEVELOPMENT
6.1. Proposed changes to the development 92. The proposed
development would see minor changes to the operation of the
site
(and which are relevant to consideration of the potential to have
off-site water
quality impacts).
a. Minor changes to internal roadways including a new
weighbridge
b. Supplementary fuel receival, storage and reclaim
c. Supplementary fuel transport equipment
6.2. Proposed Woody Biomass Fuel 94. Sources of the woody biomass
would be from legal land clearing, forestry and
waste timber from timber processing operations, biomass from
agriculture,
sawdust, untreated pallets.
95. 70% of the biomass sourced for the plant will be obtained from
approved
forestry residues, 15% from sawmill operations and 15% from
uncontaminated
wood wastes by weight only if approved and acceptable for
inclusion.
96. The fuel would be chipped and graded off-site and there will
not be any
processing such as wood chipping, debarking or shredding on the
site.
97. No post-consumer and construction and demolition recycled
timber would be
accepted eliminating any risk of copper chrome arsenate or timber
painted with
leaded paint in the feedstock.
98. The proposal would see up to 850,000 tonnes per annum of woody
biomass
burnt at the site.
99. On a daily basis, up to 70 trucks would deliver the biomass in
a wood chip form.
This additional traffic load would result in minor additional water
quality
impacts.
100. The wood chips would be stored in the stockpile which would be
managed so
that the oldest on-site wood chip is conveyed into the process
ahead of younger
wood chip. This is designed to avoid composting in place.
101. The physical area available for storage of woodchips would be
0.57 hectares.
102. Up to four days supply of woodchips, nominally 9,315 tonnes,
would typically be
stored in the stockpile and this would ensure the oldest timber in
the stockpile
was not on site for longer than a week.
Sustainability Workshop
21
103. At a density of 300kg/m3 this would give a stockpile volume of
31,000 m3.
Sustainability Workshop
7.0 PREDICTING RUNOFF QUANTITY
7.1. A predictive water balance model 104. A MUSIC model was
developed to simulate rainfall, runoff and the flow of storm
water through the site, a water balance model.
105. The model operates by predicting runoff volumes after
considering any water
used within the site such as raw water used within the process for
cooling. At
350 m3/hour this represents a large demand for water relative to
the size
(footprint of the development).
106. The model predicts runoff by simulating historical rainfall
falling across the site,
filling up pore capacity of soft and hard surfaces and then
shedding water. It
models the water balance of ponds by simulating water inflow,
evaporation and
water reuse.
7.2. Model Assumptions
7.2.1. Climate dataset 107. The model was populated with 6-minute,
rainfall which allows for conservative
modelling.
108. The long time period modelled provides a high degree of
reliability when
considering the whole range of hydrological events including wet
periods,
extreme events such as the June 2007 storm event and dry
periods.
109. The climate dataset included 40.5 years of 6-minute rainfall
data from the
Milbrodale gauge – gauge number 61309. This is the same rainfall
gauge that
Singleton Council, via its consultant Cardno, who carried out a
review of
Singleton’s Urban Stormwater Drainage systems in November
2016.
110. This gauge has unusually high reliability and appears to be
missing only a short
period of rainfall from within the whole period – 1970 to June
2010.
111. The average rainfall over the modelled period is 656 mm/annum
which is well
above the long-term average of 600mm/annum for this location. This
adds to the
conservatism of this model.
112. The rainfall dataset included several notable storm events as
follows:
i. The 1971 flood event
ii. A 1999 event with a rainfall burst of over 132mm/hour
iii. The June 2007 Pasha Bulker event
Sustainability Workshop
23
113. The use of such an extended period of rainfall for this
continuous simulation
would provide significant confidence in the results in terms of the
model’s ability
to predict how frequently runoff would occur from the site.
114. A time series of the climate data set used in the continuous
simulation is shown
below in Figure 3.
24
Figure 3 Time series of rainfall and evaporation from 1970 to June
2010 for the Milbrodale rainfall gauge
M Redbank M USIC m odel - Singleton - 40 years
Rainfall Evapo-transpiration
Sustainability Workshop
7.3. Modelled Land Uses – hydrologic parameters
115. The MUSIC model included several nodes to model the various
land uses on the
site. Undisturbed areas which do not drain into the site were
ignored.
116. Areas adopted for modelling are shown above at Figure 4.
117. With reference to Figure 4 we note that part of Catchment 5
has been assumed
to be diverted to the north and away from the raw water pond.
118. For this assumption to be valid, a grass swale, shown with a
red arrow in Figure 5
will need to be constructed to divert part of the catchment to the
south of the
electrical easement and around the raw water pond. This would be a
low-cost
way of reducing the hydraulic load on the raw water pond. This
catchment is not
used for site operations and remains well grassed. It is a clean
land use, not
requiring treatment. None the less, runoff will be treated in a 400
long grass
swale before it is further treated in the swale that runs along the
northern
boundary of the site.
119. Areas that were impervious, such as roads, boiler island,
admin building, area of
raw water storage itself etc were modelled as such. The water
treatment plant
was modelled as impervious.
120. Default hydrological parameters were adopted for modelling all
pervious areas
except the stockpile which would be highly absorbent.
121. The stockpile area was modelled as a pervious area with a
capacity to absorb
and hold water much like any soil. The stockpile also has a
capacity to evaporate
water back into the atmosphere and it is understood that heat
generated in
stockpiles results in enhanced evaporation.
122. Hydrological parameters were modified to reflect the depth of
stockpile, the
very high rate with which water would be able to percolate into a
wood chip
stockpile and the limited ability of the stockpile to hold water
for many days.
123. Previous work for Borgs Manufacturing at Oberon, which is one
of the top 10
largest timber processing facilities in the world, has shown that
large wood chip
stockpiles do leach for several days following large rainfall
events and
parameters were modified to reflect this observation.
124. As water would percolate through the pile it would follow an
extended flow path
around each chip. Once on the ground water would flow laterally
through the
pile at a slow rate or percolate downward to the subsoil drains.
Lagging was
used to reflect this.
27
125. Model predictions show that the pile would absorb and
evaporate 90% of
rainfall, with the remainder of flow released relatively rapidly as
baseflow.
126. The physical area of the raw water pond and water quality pond
were also
included in the model areas as 100% impervious to account for
direct rainfall
falling onto them.
127. The 60 ML wastewater storage was not included in the model as
it does not
discharge to Dights Creek under any circumstances.
7.4. Modelled land uses adopted EMCs 128. Event Mean Concentration
values used in MUSIC were as follows:
a. Catchments 1, 2,3 and 5 default industrial EMC values were
adopted.
b. For catchment C4, the values shown in Table 2 were adopted.
These values have
been derived based on a number of years of frequent monitoring of
runoff from
the Borgs Oberon timber production facility. The Borgs site has
large stockpiles,
shreds and debarks timber and stores timber poles, sometimes for
prolonged
periods. It is noted that while TSS is relatively low – lower than
a road catchment
for example, levels of nutrients are substantially elevated
compared to urban
stormwater and this is expected from an organics stockpile.
Sustainability Workshop
Table 2 Adopted Event Mean Concentrations for Catchment 4 -
Stockpile
Parameter Adopted MUSIC EMC (mg.L)
Standard Deviation (log mg/L)
TSS Stormflow 39.8 0.21
TSS Baseflow 15.8 0.17
7.5. Modelling the water quality pond and raw water pond
129. The water quality pond was modelled assuming 1m depth and its
surface area
was measured from a digital drawing and confirmed with aerial
imagery.
130. The water quality pond was modelled as a water quality node in
MUSIC.
131. Water reuse for dust suppression was modelled from the water
quality pond,
assuming an average depth of water applied to the stockpile area at
a rate of
1mm/day.
132. A minor modification to the water quality pond was included in
the model
which is to choke flows using a 300mm high plate placed across the
outlet
with a 150mm orifice hole at its base to allow flows to trickle
out.
133. This still allows extreme event flows to overtop the orifice
plate and flow into
the culvert.
134. The raw water pond was modelled as a sediment basin node in
MUSIC as it
has no vegetation present.
135. The raw water pond is 6 ML in volume however it is understood
that up to
4ML of raw water, pumped from the Hunter River would be present in
the
pond.
29
136. Therefore, the drawdown limit of the pond was restricted to be
equal to 2ML
to reflect the actual headroom or air space available for storage
of
stormwater runoff from the site.
137. Reuse was modelled from the raw water pond node. The daily
demand for
water from the pond would be 8,791.2kL/day which is 366.3 kL/hour.
This
equates to a demand of just over 100 l/s for cooling from the
pond.
Sustainability Workshop
8.0 RESULTS & PREDICTED COMPLIANCE
8.1. Frequency of discharge 138. The MUSIC model was run and a
daily flux file analysed to determine the
frequency of runoff from the raw water quality pond.
139. The model predicted 3 runoff events in 40.5 years. On average,
this is less
than 1 runoff event every 10 years.
140. The model predicts 99.7% of all runoff will be retained and
reused on the site.
The 0.3% of runoff that is discharged occurs during the 3 runoff
events where
water is discharged from the site.
141. The 6-minute rainfall data captures the storm burst and models
the flux of
the raw water pond after stormwater has flowed in from the site and
water
has been extracted for pumping.
142. A gross error check was conducted to check this result as
follows.
143. We extracted the largest predicted single daily runoff volume
from the
MUSIC model. This was predicted to occur during the June, 2007
storm event
where 133mm of rainfall was recorded at the gauge in one day. The
volume
of runoff for that day was predicted to be 7,508m3. The daily
demand is 8,407
m3 and so if we used a daily time step model it would result in
zero discharges
from the site over the 40.5 year model period.
144. This demonstrates why it is important to adopt a 6-minute time
step for
modelling and how it is a more conservative approach. It also
validates that
the 6-minute time step model is correctly predicting off-site
discharge events
which only occur because of rare and extreme rainfall.
8.2. Water quality impacts 145. The MUSIC model was chosen for this
project because, as a continuous
simulation, it simulates the whole spectrum of flow events using
real world
climate data from a gauge very close to this site.
146. This model predicts that the site effectively has no “chronic”
discharges. In
other words, the site is predicted to discharge only during extreme
rainfall
events.
147. One can therefore confidently conclude that provided key
model
assumptions are valid, the existing and proposed development would
have no
aquatic ecosystem impacts and would not result in water
pollution.
148. Everyday risk for Australian streams is overwhelmingly what
leads to a
decline in waterway health. This is often called urban stream
syndrome –
where urban streams receive degraded runoff every time it rains,
and they do
not have time to recover from one event to another.
149. Moreover, the change in flow regime, not just the chemical
changes, can
result in degraded waterways. The problem is one of being
directly
connected. That is polluting land uses are described as being
directly
connected to creeks.
150. The existing and proposed operations at Redbank Power Station,
would
remain, in water quality terms, effectively (99.7%) disconnected
from Dights
Creek. This is outcome ensures that both the existing operation and
the
proposal will have no adverse impacts on the creek.
151. At Redbank, 99.9984% of the time there will be no discharge
from the site.
8.3. Water quality discharge during extreme events
152. Extreme events in hydrological terms happen infrequently. In
the context of
this site, discharge less often than once every ten years would
occur during an
extreme weather event. This equates to less than 0.0016% of the
time.
153. For example, the MUSIC model predicts that one of the
historical spill events
would have been the June, 2007 Pasha Bulker storm event. This event
saw
more than 133mm of rainfall recorded in one day at the gauge and
was the
worst flood between 1971 and 2007.
154. The external catchment draining to the point of discharge is
estimated at 147
hectares. The stockpile area, which is that part of the site which
would
contribute more pollution, is 0.57 hectares. See Figure 5.
155. The discharge to Dights creek from the site would see
stockpile runoff diluted
by a factor of 250.
Sustainability Workshop
32
Figure 5 Approximate current catchment area upstream of the point
of Redbank discharge
156. The extremely low frequency of discharge combined with the
high level of
dilution that would occur would ensure that site discharges during
extreme
events would not result in adverse impacts off the site.
157. This statement implicitly considers the very poor water
quality that
naturally occurs during these extreme events from all land uses
including
pristine National Parks. These events naturally shape creeks and
erode
gullies and move vast volumes of debris, sediment, nutrients and
tannins.
8.4. Predicted compliance with applicable development
standards
158. The principal NSW government policy guideline applicable to
this site would be
the “Environmental Guidelines: Composting and related Organics
processing
Facilities” published by the Department of Environment and
Conservation
(NSW) 2007. This document sets criteria for composting sites and
has
established a 1 in 10 year discharge limit for leachate storage
dams.
159. If one was to accept that the raw water storage pond was in
effect a leachate
dam and that it is predicted, conservatively, to spill only 3 times
in 40 years then
the proposal would comply with the only relevant NSW Government
policy
document.
160. It is noted that Singleton Shire Council does not have any
applicable
development water quality standards.
9.0 MODELLING THE POST DEVELOPMENT SITE
9.1. What are the differences between pre and post development
models?
161. The only differences that arise in the way one would predict
pollution from the
proposal lies in the use of woody biomass instead of coal. In most
other
respects the proposal remains the same noting that there is a
proposed minor
increase in road surface on the site and an increase in
traffic.
162. The increased traffic volume of 70 trucks per day is unlikely
to result in a
detectable change in predicted discharge water quality as typical
industrial
EMC values inherently include multiple truck movements per
day.
163. Moreover, the fact the site discharges less often than once
every ten years
would ensure impact from additional traffic, if it exists, would
not result in any
adverse impacts off the site.
164. The change in the reduction of ash is considered immaterial to
effluent quality.
165. The principal and material difference between woody biomass
and coal is
understood be as follows:
166. Coal is more likely to produce heavy metals at low
concentrations in leachate
though it is known that timber can leach metals at low
concentrations. It is
thought these are unlikely to be at levels which would cause harm
as they have
been sourced from the soil material on which the trees have grown,
i.e. they
would be naturally occurring in the environment and in the soils in
that
environment.
167. Coal is more likely to produce sulphur and sulphuric acid in
leachate however it
is noted that Australian coal is lower in sulphur and therefore
this is less likely
to be of concern.
a. Elevated levels of nutrients, especially nitrogen and dissolved
organic
nitrogen (measured as total Kjeldahl nitrogen (TKN).)
b. Elevated levels of BOD and COD.
c. At the Borgs Manufacturing site at Oberon, an EMC value for TN
of 10 mg/L
is adopted. This is roughly 5 times the value of a typical
industrial site.
Phosphorus too is elevated but not significantly.
Sustainability Workshop
34
169. None of these differences have any relevance to a
determination of whether the
development proposal will result in additional off-site
impacts.
170. This is because the site, because of its extraordinarily high
demand for raw
water and stormwater, consumes 99.7% of all stormwater runoff and
would
discharge to stormwater less than once in ten years on
average.
171. The remaining 0.3% of annual runoff is diluted 250-fold and
only discharged
when ambient water quality in receiving waters would, regardless of
the
development proposal, be extremely poor.
9.2. Predicted maximum indicator pollutant concentrations
172. The MUSIC model was used to estimate the maximum, 40.5 year
discharge
concentration of TSS, TP and TN. These are the principal pollutants
of concern
emanating from a wood chip stockpile and they are the only
pollutants that can
be modelled using MUSIC.
173. The predicted maximum discharge concentrations, occurring less
than once
every ten years are shown in Table 3.
Table 3 Predicted Maximum Discharge Concentrations
Parameter 100th percentile
10.0 WATER POLLUTION RISK
10.1. Risk of off-site water quality impacts 174. Operation of the
raw water storage to provide water needed for cooling sees
the
raw water pond spill on only 3 occasions in the 40.5 years of
simulation period.
175. This equates to retention of 99.7% of all stormwater runoff on
the site.
176. Provided that the raw water storage is operated with 2 ML
headroom, and a
condition of consent is invited to ensure this outcome, the
development
proposal is extremely unlikely to result in any off-site adverse
water quality
impacts.
10.2. Acute risk of water pollution 177. There are a large number
of controls in place on this site to prevent and monitor
for an accidental spill including extensive use of spill
bunds.
178. The site would operate under its numerous existing safe work
procedures which
include spill management procedures.
179. The site operates in accordance with its Pollution Incident
Response
Management Plan which can be found here:
https://verdantearthtechnologieslimited.com/verdant-new-site/wp-
content/uploads/2021/08/001-PIRMP-V4.pdf
180. This means that the development proposal, using all existing
bunds and
emergency spill controls such as water level, flow, salinity and
oil on water real
time monitoring, is unlikely to cause water pollution from an
accidental spill.
181. It is very much in the interests of VET Ltd to ensure that any
spill is detected as
soon as possible and before it has the potential to be pumped into
the on-site
treatment plant where it would foul expensive water treatment
equipment.
11.0 RECOMMENDATIONS 182. The following conditions of consent are
invited:
a. Operate the raw water pond with a minimum of 2ML headroom.
Reason: to
ensure stormwater runoff from the Redbank site occurs less often
than once
in 10 years.
b. A new grassed swale, as shown by a red arrow in Figure 4, is to
be
constructed. Reason: to reduce the area of catchment 5 that
contributes
stormwater to the raw water pond.
c. A stainless-steel orifice plate, 300mm high, with a 150mm
diameter circular
opening in its base, be placed over the outlet of the water quality
pond.
Reason: to detain water in the pond for an extended period which
will
improve discharge water quality and help reduce the frequency of
off-site
discharge.
d. The water quality pond shall be aerated to ensure that it
maintains high
levels of dissolved oxygen. Reason: there is a risk that the water
quality
pond will receive elevated levels of BOD. This may result in the
development
of anoxic conditions on the water quality pond under low rainfall
conditions.
e. Construct a 2m vegetated buffer strip between the stockpile and
the
concrete channel. Reason: this will help reduce the export of
woodchip from
the stockpile.
183. When it is feasible to do so or following any observations of
poor water
quality in the water quality pond, consider installing a Barramy
Trap
upstream of the water quality pond. This will enable the dry
storage of
woodchips which would see reduced leaching.
Sustainability Workshop
37
Figure 6 Example of Barramy Vane Trap installed in the Blue
Mountains.
Sustainability Workshop
Appendix A
Curriculum Vitae
www.sustainabilityworkshop.com
Mark has 25 years of professional experience as a Chartered Civil
and
Environmental Engineer. As a water engineer, he leads in areas of
local government policy, water cycle management and environmental
impact assessment. He often trains local and State Government and
industry.
Mark sits comfortably between the private and public sectors having
worked in both sectors for many years. He bridges the gap between
the
two to deliver affordable sustainable designs and gain approvals
often where others have struggled. Mark also works with academia,
guiding research to create tangible outcomes for industry.
Career highlights include:
1) He is currently working with Blacktown Council to lead a $2
million State and Council funded research project into the
long-term field performance of bioretention systems in western
Sydney. This is the
only long-term study of bioretention systems.
2) Carrying out the first independent evaluation (peer review) of
a
proprietary stormwater quality improvement device for Stormwater
Australia.
3) Carrying out numerous peer reviews of proprietary
stormwater
treatment devices for Blacktown Council and which are adopted by
most other NSW Councils.
Current Positions:
Director and Principal Engineer Sustainability Workshop Pty Ltd
(2012 to present) Consultant Engineer, Blacktown City Council (2013
to present) Independent Evaluation Panel – Stormwater Australia
Peer Reviewer – Water Science and Technology Journal.
Name:
Qualifications:
Chartered Professional Engineer, MIEAust Bachelor of Civil and
Environmental Engineering (1998) Hons (First Class), UTS Bachelor
of Economics (1990), Sydney Uni
Previous Employers:
WSP & RPS in the UK 2006-2012 Storm Consulting (Australia)
2000-2006 Arup (Australia) 1998-2000
Key Capability
Hydrology and hydraulics, Water Quality Management, Water Sensitive
Urban Design, Creek Rehabilitation and Stabilisation, Drainage
design, Flood risk and EIA, Integrated Water Cycle Management,
Strategic planning, Policy Development, Training and Capacity
Building
www.sustainabilityworkshop.com
4) Principle Author of the Blacktown Water Sensitive Urban
Design
Standard Drawings and co-author of the Blacktown WSUD Handbook for
Development.
5) Lead Designer of the multi award winning Blacktown
International
Sports Park stormwater harvesting system. Project value $6.5
million.
6) Design and implementation of the first stormwater quality offset
scheme in NSW also for Blacktown Council.
7) Planning and detailed design of the stormwater drainage
system
and water cycle management for a 50 hectare campus for Borgs
Manufacturing at Oberon. This is a State Significant
Development
that sees Borgs become one of the top 10 engineered timber
producers in the world.
8) Receiving a Green Globe Award from the Premier of NSW for
work
with Mirvac on the water cycle management system for Ashgrove
Estate at Auburn.
9) Designing the first on-line planning tool in NSW to help
developers identify applicable planning controls in the whole of
the Blacktown LGA. See www.s3qm.com.au
10) Undertaking a detailed Integrated Water Cycle Management System
for Area 14 at Port Macquarie.
11) Designing the first estate in NSW to include rainwater tanks –
Elambra Estate at Gerringong.
12) Designing the first combined bioretention and stormwater
harvesting scheme in Australia in 2003 for Kiama Council.
Mark also peer reviews relevant (stormwater related)
professional
scientific publications for the highly regarded Water Science and
Technology Journal, published by the International Water
Association.
Mark enjoys the dynamic of a team - leading teams of planners,
Architects, scientists and engineers.
Mark is currently an active Stormwater NSW member as well as a
Member
of the Institution of Public Works Engineers, Australia.
AWARDS
Mark has been responsible for leading teams of Engineers and
Scientists in undertaking planning, design and construction
supervision for a range of highly innovative civil and
environmental engineering projects. He is
regarded as one of Australia’s leading Sustainable Urban Drainage
system Engineers and his work has been repeatedly awarded.
• 2017 Stormwater NSW Award of Excellence for the Blacktown
Developer WSUD Toolkit.
• Finalist Greater Sydney Commission Planning Awards – for
the
Offset Scheme developed for Blacktown City Council. • 2016 State
and National Awards of Excellence in Strategic Planning
for the latest incarnation of the Blacktown WSUD and IWCM
DCP.
• 2015 State Award of Excellence for the Angus Creek stormwater
harvesting scheme.
• 2008 Stormwater Industry Association National Award of Excellence
for a Stormwater Quality Treatment Device.
• 2008 NSW State Premier’s Green Globe Award - Ashgrove
Estate.
• 2008 Stormwater Industry Association Award for Excellence in
Stormwater Management for the Ashgrove Estate.
• 2008 NSW Stormwater Industry Association Award for Excellence in
a Stormwater Quality Measure - Exfiltration Stormwater Treatment
Systems.
• 2007 Stormwater Industry Association Awards for surface and
Groundwater Management - Kinross Industrial Estate.
• Stormwater Industry Association National Award of Excellence in
Water Sensitive Urban Design, 2004, for the Hindmarsh Park
“Bioretention Filter and Elambra Estate Projects. This is
Australia’s
premiere award for water sensitive urban design. • Finalist,
Institution of Engineers, Australia, 2005 for the Kiama
Sand Filter and Elambra Estate Projects. • Case Earth Awards, 2004,
Campbeltown Link Constructed Wetlands
Recent Publications (most pub’s available for download on
website)
Alim A, Rahman A, Tao Z, Griffith M, Garner, B, Griffith, R and
Liebman M, Green Roofs toward Sustainable Development: A scoping
Review of
Australia Practice, Water Research Journal, under review.
Liebman M, Is it worth Sacrificing water quality to create publics
for stormwater?, Stormwater Australia National Conference,
2021.
Liebman M, Jennings R, Eberl G, Peterson R, The challenges of
building $270M of stormwater infrastructure for Blacktown City
Council,
Stormwater Australia National Conference, Sydney, 2018.
Liebman, Milenkovic and Taylor, How to Make it Easy to get a DA in
a Notoriously Complex LGA. Stormwater NSW State Conference,
Newcastle,
2017.
Sustainability Workshop
Appendix B
The Law Specialists
Liability limited by a scheme approved under Professional Standards
Legislation. Legal practitioners employed by Fishburn Watson
O'Brien Pty Limited are members of the scheme.
Fishburn Watson O'Brien Pty Ltd ABN 70 163 802 319
Our ref RF:DP:2210330:kh Watson House 300 George Street Sydney NSW
2000
Phone (02) 6650 7000 Fax (02) 6651 4853
www.fwolaw.com
02 6650 7038
[email protected]
Mr Mark Liebman Sustainability Workshop 4 Park Avenue Blackheath
NSW 2785 Privileged and Confidential
By Email:
[email protected]
Dear Mark Hunter Development Brokerage Pty. Limited (t/as HDB Town
Planning and Design) v Singleton Council Case Number 2021/00128111
– Class 1 Application Modification Application DA 183/1993, 112
Long Point Road, Warkworth
We refer to our letter of 17 September 2021 and provide the
following further instructions.
We request that you address the following matters:
1. Describe the existing approved stormwater management system at
the Premises.
2. Review the likely environmental impact of the proposed
modifications with respect to the existing approved stormwater
management system.
3. Identify whether the proposed modifications give rise to the
need for any changes to the existing stormwater management system
to ensure that the likely environmental impact is adequately
managed. If so, describe the nature of those changes.
Please give me a call if you have any questions.
Yours faithfully, FISHBURN WATSON O'BRIEN
ROSS FOX Principal Accredited Specialist Planning and
Environment
M:\Docs\2210330\3124730.docx
The Law Specialists
Liability limited by a scheme approved under Professional Standards
Legislation. Legal practitioners employed by Fishburn Watson
O'Brien Pty Limited are members of the scheme.
Fishburn Watson O'Brien Pty Ltd ABN 70 163 802 319
Our ref RF:DP:2210330:kh Watson House 300 George Street Sydney NSW
2000
Phone (02) 6650 7000 Fax (02) 6651 4853
www.fwolaw.com
02 6650 7038
[email protected]
Mr Mark Liebman Sustainability Workshop 4 Park Avenue Blackheath
NSW 2785 Privileged and Confidential
By Email:
[email protected]
Dear Mark Hunter Development Brokerage Pty. Limited (t/as HDB Town
Planning and Design) v Singleton Council Case Number 2021/00128111
– Class 1 Application Modification Application DA 183/1993, 112
Long Point Road, Warkworth
We act for Verdant Earth Technologies Limited (formerly Hunter
Energy Limited), the new owner of Redbank Power Station. HDB Town
Planning and Design (HDB) lodged the modification with Council on
behalf of our client. HDB agreed to be the Applicant in the Class 1
proceedings which have commenced in the Land and Environment
Court.
1. Your Instructions
1.1 We would like to retain you as an expert witness addressing a
contention 12(a) of the Council’s Further Statement of Facts and
Contentions of 15 September 2021 relating to the impacts of the
particular chemistry of the stormwater generated by the proposed
development. Your expert evidence would be limited to the aspects
of those matters in which you have expertise.
1.2 Contention 12(a) is as follows (italicised text marks additions
in the Council’s Further Contentions):
“The Stormwater Impact Assessment submitted with the modification
application does not discuss and assess the particular chemistry of
the potential generation and runoff of leachate from the biomass
stockpile that may contain various contaminants, tannins and
lignins, and whether the existing stormwater management system at
the site is suitably designed and constructed to mitigate the
potential pollution of waters from leachate. The MUSIC model
provided uses source nodes to represent the biomass material
proposed to be stockpiled on site, and calculate the efficacy of
the existing pollutant treatment train on site. It is unclear
whether the source nodes in the provided MUSIC model accurately
depict the chemistry of the leachate generated from the degrading
biomass material, which is expected to be of
- 2 -
M:\Docs\2210330\3124730.docx
varied toxicity, have the potential to create PH imbalance and
possibly produce ammonia (NH3). It must be demonstrated that the
MUSIC model accurately depicts the chemistry of the leachate from
the biomass, and that the leachate is sufficiently treated by the
existing treatment train before water leaves the site.”
2. Background
2.1 Redbank Power Station is located at Long Point Road and Jerrys
Plains Road, Warkworth (part Lots 1-3 DP 247820 and Lots 4-5
DP247820).
2.2 The existing Redbank Power Station is a 120-megawatt power
plant fuelled (historically) by coal washery tailings supplied from
the Warkworth coal preparation plant.
2.3 The original development consent (DA183/93) was granted by the
Land and Environment Court on 10 November 1994.
2.4 A class 1 appeal was filed in the Land and Environment Court on
7 May 2021, appealing against Singleton Council (Council) deemed
refusal of an application to modify the development consent.
2.5 The modification seeks to add the use of biomass as an
additional fuel among other things.
2.6 Council’s Amended Statement of Facts and Contentions (SoFC) was
filed on Wednesday, 15 September 2021. The Applicant’s response to
the SoFC is due 17 September 2021.
2.7 The Applicant’s further information is to be provided by 24
September 2021.
2.8 Joint reports of experts by 1 October 2021.
2.9 The matter is scheduled for hearing on 11 – 15 October
2021.
2.10 In relation to Contention 12(a), we note that:
2.10.1 The treatment of runoff from the woody biomass pile has been
modelled in RGH Consulting Group’s report dated July 2021 using
MUSIC modelling software.
2.10.2 Pollutant loads from a “woody biomass pile” are not defined
in MUSIC, so it is not possible using default settings in the MUSIC
software to model the pollutant load reductions except for TN, TP
and TSS.
2.10.3 The chemistry of leachate from a woody biomass pile is
influenced by tannic acids, can have a low pH and moderate chemical
oxygen demand.
2.10.4 As a proxy, RGH Consulting has modelled runoff from a quarry
and an agricultural site, which has not satisfied fully Singleton
Council.
2.10.5 We have reference data on the chemical characteristics of
woody biomass leachate, though the MUSIC modelling software does
not adequately address this issue.
- 3 -
M:\Docs\2210330\3124730.docx
2.10.6 As not all water is fully contained on the site, the site on
an annualised basis will discharge around 16% of total inflow (this
will need to be confirmed).
3. Expert Witness Code of Conduct
3.1 Before commencing work or undertaking any site inspections, we
require you to undertake the work in accordance with the Expert
Witness Code of Conduct, Schedule 7 of the Uniform Civil Procedure
Rules 2005.
4. Your Preliminary Brief
4.1 Please note that you can access the documents at the link which
accompanies this email. The documents are as follows:
4.1.1 Expert Witness Code of Conduct.
4.1.2 Amended Statement of Facts and Contentions from Council dated
15 September 2021.
4.1.3 Planning Report – Section 4.56 Application to Modify DA183/93
– Redbank Power Station by URBIS dated 11 August.
4.1.4 Site Layout Plan – Biomass Unload and Storage Area by HDB
numbered 21017 Revision B dated 29 July 2021.
4.1.5 Proposed Redbank Power Station Plant Biomass Conversion
Drawings by B&PPS numbered as ‘C12181-000-100 Rev A’,
‘C12181-000-111 Rev A’, ‘C12181-000-112 Rev A’, ‘C12181-000-113 Rev
A’, and ‘C12181-000-114 Rev A’.
4.1.6 Site plan by Alstom numbered as ‘80034-001-M-GA-000-5001
A0’.
4.1.7 Site plan by Alstom numbered and ‘80034-025-M-GA-000-9176
A1’.
4.1.8 Concept study by B&PPS titled ‘Biomass Handling Plant
Concept Study B&PPS Report (C12156-03)’, by B&PPS, Rev 4
dated 18 June 2021.
4.1.9 Redbank QA/QC Supply Chain and Material Handling dated 30
July 2021.
4.1.10 Noise Impact Assessment by Muller Acoustics Consulting. Rev
3, dated 11 August 2021.
4.1.11 Stormwater Management Plan Report by RGH Consulting Group,
Rev E, dated July 2021.
4.1.12 Updated air quality assessment titled ‘Air Quality Impact
Assessment’ by EMM, version 2 dated 9 August 2021.
4.1.13 Updated transport assessment titled ‘Transport Assessment’
by Ason Group, Issue IV, dated 10 August 2021.
4.1.14 Updated traffic management plan titled ‘Operational Traffic
Management Plan’ by Ason Group, Issue III, dated 10 August
2021.
4.2 Any opinion you provide must be based wholly or substantially
on specialised knowledge you have based on your study, training or
experience. If you are
- 4 -
M:\Docs\2210330\3124730.docx
unable to provide an opinion on a matter, please note this and the
reasons you consider you are unable to provide said opinion.
5. Your engagement
5.1 Please note that while we have engaged you to act as an
independent expert witness, our client will be responsible for any
invoices issued by you.
5.2 Our client’s details are as follows:
Verdant Earth Technologies Limited ACN 624 824 791 Contact: Richard
Poole, Director
0417 941 297
[email protected] Arthur Phillip Pty Ltd Level
33, 52 Martin Place SYDNEY NSW 2000
6. Next steps
6.1 Your report is required to be filed and served on 24 September
2021.
6.2 Please also confirm your availability to attend the hearing
(online) from 11-15 October 2021.
6.3 Lastly, please provide our client with an estimate of your fees
and engagement terms.
If you have any questions or wish to discuss this matter generally,
please contact me.
Yours faithfully, FISHBURN WATSON O'BRIEN
ROSS FOX Principal Accredited Specialist Planning and
Environment
Sustainability Workshop
Appendix C