BLACKTOWN STORMWATER
HARVESTING & REUSE
SCHEME
FINAL REPORT
May 2015
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
Page 1
Contents
1.
EXECUTIVE SUMMARY ................................................................................................................ 4
2.
PROJECT OVERVIEW.................................................................................................................... 6
3.
4.
5.
2.1.
Location ............................................................................................................................... 6
2.2.
History and Context ............................................................................................................ 6
2.3.
How the Scheme Works ...................................................................................................... 7
2.4.
Project status .................................................................................................................... 17
PROCESS AND METHODS .......................................................................................................... 18
3.1.
Project governance ........................................................................................................... 18
3.2.
Project activities and conduct ........................................................................................... 18
3.3.
Water quality management .............................................................................................. 19
3.4.
Stakeholder and Community Consultation ....................................................................... 20
PROJECT ASSESSMENT .............................................................................................................. 21
4.1.
Objectives and key performance indicators ..................................................................... 21
4.2.
Project finance .................................................................................................................. 22
4.3.
Potable water savings achieved by the project ................................................................ 24
4.4.
Levelised cost of water supplied as a result of the project .............................................. 24
4.5.
Amount of GHG emission offset ....................................................................................... 25
4.6.
Other environmental benefits .......................................................................................... 26
EXPERIENCE SHARING AND LESSONS LEARNT .......................................................................... 27
5.1.
Project results and outcome realisation ........................................................................... 27
5.2.
Major project issues .......................................................................................................... 27
6.
PROJECT FUTURE ...................................................................................................................... 29
7.
CONCLUSIONS ........................................................................................................................... 30
ATTACHMENTS.................................................................................................................................. 31
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
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Report Sign Off
Function
Author/Project
Manager
Position
Catchment
Projects Officer
Name
Craig Bush
Approved by
Director Design
and development
Glenys James
Approved by
General Manager,
Blacktown City
Council
Kerry Robinson
Signature
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
Date
Page 3
1. EXECUTIVE SUMMARY
The Blacktown International Sportspark (the Sportspark) is a high profile regional sporting complex
located in Rooty Hill, approximately 35km west of Sydney, NSW. The Sportspark is used by Cricket
NSW, AFL NSW/ACT, Western Sydney Wanderers, Softball NSW, Athletics NSW and many more. As
the facilities are required to be at a high standard Blacktown City Council, with assistance from the
Australian Government, has built the Blacktown Stormwater Harvesting and Reuse Scheme (the
scheme) to supply an alternative supply of water to this facility and surrounding reserves.
The scheme is capable of collecting and cleaning 200 million litres of stormwater per year, which is
equivalent to approximately 80 Olympic sized swimming pools. The water will be used to irrigate the
Sportspark, Anne Aquilina Reserve, Kareela Reserve and Charlie Bali Reserve, as well as topping up
the Nurringingy Reserve ornamental lakes. See figure 1 for location of the scheme in relation to
Sydney.
The scheme was originally designed as a Managed Aquifer Recharge scheme where the collected
stormwater was to be pumped into an aquifer and stored in the aquifer until it was extracted for
irrigation. Intensive drilling investigations discovered that the aquifer was too deep and the flow
rates were insufficient to support such a large scheme therefore the managed aquifer recharge
scheme was abandoned. The stormwater harvesting scheme was then modified to store the
stormwater in above ground storages such as ponds and wetlands.
Figure 1 – Location of Blacktown Stormwater Harvesting and Reuse Scheme in relation to Sydney
The scheme has the following benefits for Blacktown City Council, including:
-
Reducing potable water used for irrigation and toilet flushing
Increasing the drought resistance of the sporting fields during drought periods
Improving the quantity of water being supplied to the Sportspark
Improving the condition of Angus Creek.
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The Australian Government, through the National Urban Water and Desalination Plan, contributed
$2,212,500 to the project. The NSW government also contributed $286,000 to the scheme via the
Waste and Sustainability improvement Program. Blacktown City Council, through the Environmental
Stormwater Management Program, contributed $3,737,860 to the project and therefore the total
project budget was $6,236,360.
As of May 2015 the Scheme is fully constructed and commissioned but is undergoing extensive
water quality monitoring to ensure the water being supplied by the scheme is fit for purpose for
irrigation and toilet flushing. Council intends to have the scheme fully operational before October
2015 to make the most of the upcoming summer when irrigation demand will be at its highest.
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2. PROJECT OVERVIEW
2.1.
Location
The Blacktown Stormwater Harvesting and Reuse Scheme (the scheme) collects stormwater from
Angus Creek, which has a 655ha catchment that drains the suburbs of Rooty Hill and Minchinbury.
The catchment consists of low and medium density housing with small areas of commercial
development. Approximately 35% of the catchment is classified as impervious (hard surfaces such as
roads, paths, roofs etc.). The Angus Creek catchment generates approximately 2 billion litres of
stormwater in an average rainfall year and the scheme has approval to harvest 200 million litres per
year, which is equivalent to 10% of the average total flow.
The Stormwater is collected, treated and distributed in the Blacktown International Sportspark,
Rooty Hill within the Chifley electorate.
2.2.
History and Context
In 2007/8 the Australian Football League (AFL) and Cricket ovals were constructed in the Blacktown
International Sportspark (the Sportspark). As part of this project Council installed a water quality
treatment system to treat recycled water that was to be delivered by Sydney Water as part of the
recycled water pipeline (purple pipe), similar to the infrastructure in Rouse Hill. Shortly after the
fields were constructed Sydney Water decided not to install the recycled water pipeline to the area.
This meant that Council had the infrastructure to support recycled water but no supply. To
compound this Sydney Water also did not upgrade the potable water supply at the time of
construction of the sporting fields as the recycled water pipeline was going to be used for irrigation,
which is the biggest usage of water. Therefore the sportspark not only didn’t receive the recycled
water pipeline they also didn’t receive the upgrade in the potable water supply line which meant
that there was a considerable shortfall of water being supplied to the Sportspark (a rate of less than
5 litres a second). The managers of the Sportspark (Blacktown Venue Management) were then
forced to ration their water during dry and hot periods as the water supply was not substantial
enough to irrigate all fields. This meant that only the high profile fields received water and the “back
fields” were allowed to degrade. In response Council started to investigate ways that the Sportspark
and the surrounding fields can be irrigated using an alternative supply of water such as stormwater
harvesting and reuse.
The first potential solution was a managed aquifer recharge scheme. This scheme would pump
stormwater from Angus Creek into an aquifer and then extract this water when it was required for
irrigation. Blacktown City Council undertook extensive investigative drilling to determine if the
aquifer underneath the Sportspark was suitable for such a scheme. The drilling results clearly
indicated that this type of scheme would not be suitable in the area as the depth and size of the
aquifer were inadequate for the size of the scheme. Further investigation into an alternative scheme
was required.
The preferred approach is to use an above ground stormwater harvesting system. Council will
harvest the stormwater from Angus Creek but instead of storing the water in the aquifer is stored in
a series of ponds in the Sportspark before final treatment and distribution. The following section will
explain how the scheme works in more detail.
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2.3.
How the Scheme Works
2.3.1. Off-take Point
As part of the Scheme Blacktown City Council carried out bank stabilization in the creek (photo 1)
and built a large rock lined dam on the eastern bank of Angus Creek between the M7 overpass and
the western railway line to Penrith. This dam is capable of storing 1 ML of stormwater.
Photo 1: Angus Creek
Photo 2: The Offtake dam (half capacity)
The flow of stormwater in the creek is diverted into the offtake dam via a flow control structure and
a tilting weir system.
The flow control structure, which is concrete structure that is built across the creek, allows Council
to calculate the stormwater flows by measuring the height of the water as is passes through a notch
in the concrete structure. The tilting weir has pollution deflector veins (similar to a Baramy Gross
Pollution Trap) that prevent floating pollutants from entering the pool. Behind the deflector is a steal
tilting weir that can be adjusted to allow flows above 10 litres per second into the pool. This ensures
that Council will only be harvesting stormwater during rainfall events and that environmental flows
are not taken. The weir can also be used to prevent any flows into the offtake pool in case there is
chemical spill or similar in the catchment. Council has also installed a flow monitor in the creek that
will turn the Offtake Pool pumps on when flow in the creek is measured above 10 litres per second.
This is a secondary measure to ensure there is ample flow in the creek when harvesting is to occur.
Photo 3: The flow control structure
Photo 4: The tilting weir with pollution
deflector
The way in which water enters the offtake pool is shown in Figure 2 below.
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2
3
5
6
1
4
7
Key:
12345-
Angus Creek
bed control structure
tilting weir structure
offtake dam
steel cage inlet to pump
station
6- pump station
7- maintenance access point
blue arrow = flow of stormwater
large blue arrow = high flows
Figure 2: Aerial view of the Offtake Pool structure and an indication of how it works.
During heavy rainfall events when the flow in the creek reaches above the wall dividing the creek
and the offtake pool the water will flow into the offtake dam directly over the wall.
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Once the stormwater is collected from the creek it will pass through a steal mesh cage (marked 5 in
figure 2) excluding any debris such as litter, branches, and leaves. Once the water has passed
through the cage it is pumped to the harvest storage ponds. The pumps in the offtake pump station
can pump up to 40 Litres per second and use a variable speed drive. The pump station also has a
turbidity and electric conductivity meter that measures the quality of the water being harvested. If
the water quality fails to meet the correct standard the pumps are switched off until the water
settles out. This prevents the system from harvesting unsatisfactory water.
2.3.2. Harvest Storage Ponds
The three harvest storage ponds are located in the center of the Sportspark and serve a dual
purpose. The ponds were originally built as a flood mitigation measure that receives runoff from the
roads, car parks, open spaces, and sporting fields via swales and piped systems. To increase the
storage potential the ponds were deepened from 5ML to approximately 8ML. Works were also
required to hydraulically connect the ponds so that the water levels rise and fall at the same rate.
The water from the Offtake dam is pumped into pond 1 and the water is extracted from pond 3.
Separating the inlet and outlet gives the contaminants in the water an opportunity to settle out.
To provide additional treatment Council has install over 400 square meters of floating wetlands and
riparian vegetation on the outer edge of the ponds. The floating wetlands act as a filter, their roots
dangle in the water removing soluble nutrients and using it for plant growth. These floating wetlands
will also prevent any algal growth that is known to occur in the ponds during hot summers. The
floating wetlands and bank vegetation also provide habitat for local birds, frogs, and other wildlife.
Photo 5: Pond 3 with outlet cage
Photo 6: Pond 2 with floating wetlands
Photo 7: Floating wetland raft structure
Photo 8: Root structure of floating wetland
(photo from Sean Harris)
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P3
Floating wetland
rafts
Key:




Blue lines = stormwater
harvesting flow
Yellow lines = swale or piped
flow
Orange lines = flood flows
Green lines = hydraulic
connection between ponds
P2
P1
Figure 3: Aerial view of the Harvest Storage Ponds
The water is pumped from harvest storage pond 3 using a 12 litre per second pump. Before the
water is pumped it has to pass through a steal mess cage similar to the Angus Creek offtake dam
pump station. This cage is to prevent debris greater than 5mm from entering the pumping station
and being pumped into the treatment wetland.
2.3.3. Treatment Wetlands
The treatment wetland is approximately 3,300m² in size and was planted out with over 50,000
aquatic/wetland plants. The dense planting in the treatment wetland absorbs excess nutrients, and
removes heavy metals and hydrocarbons from the system. This treatment wetland has been
designed to act as a polishing system for the water and to reduce the amount of mechanical
treatment required at later stages.
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The treatment wetland features a series of level spreaders and baffles to ensure that the flow of
water into the wetland is evenly distributed, and to minimize the chances of directional flow paths.
The baffles force the water to take a particular path and lengthen the time taken for the water to
travel from the inlet to the outlet improving water quality.
There is also a level control device that allows Council to control the height of the water in the
wetland and to drain the wetland, if maintenance is required.
One issue during the establishment phase was the predation of the plants by the large water bird
population in the area. The birds, in particular swamp hens, damaged and removed plants which
increased the establishment time. This issue was managed by increasing the water level making it
harder for the water birds to reach the bottom of the wetland and remove the plants.
Photo 9: The treatment wetland
Photo 10: The wetland inlet, pool and level
spreader
The outlet structure to the wetland is a pit with a shroud that surrounds the inlet. This is different to
the other outlets as the shroud protects the inlet from floating debris and any hydrocarbons from
entering the pit as the water can only access the pit a few centimeters below the surface. Compared
to the cage systems that only prevents debris.
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2
1
4
3
5
Key:
123456-
Inlet pipe and pool
Level spreader
Deep pool section
Level control device
Baffle system
Outlet pit and pump
station
Blue arrow = flow
Yellow arrow = inflow from
sporting field runoff
6
Figure 4: Aerial view of the treatment wetland
The water is pumped from the wetland pump station using a 12 litre per second pump into the AFL
pump shed where it will receive mechanical treatment, as described below.
2.3.4. Treatment and Storage Tanks
Council requires the water produced by the scheme to be fit for purpose, including no access
restrictions for irrigation and toilet flushing, which is considered a level 1 treatment when referring
to the Australian Guidelines for Water Recycling. The water quality produced by the scheme will
therefore need to be low in turbidity and E.coli levels. The ponds, floating wetland and treatment
wetland will remove the majority of sediment (turbidity) and bacteria (E.coli) from the water before
the mechanical treatment process. To ensure that the water quality is fit for purpose Council has
installed the following filters and disinfection methods to further polish the water.
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2.3.4.1. FIRST PHASE TREATMENT
2.3.4.1.1.
Chlorination System
A Sodium Hypochlorite (liquid chlorine) dosing system will add chlorine to the water removing a
large variety of disease causing pathogens, such as bacteria, viruses, and protozoans. This system
has the following features:
o
o
o
o
This chlorination system has a 1000L tank that is installed in its own storage shed to reduce
impacts of heat and direct sunlight that reduces the concentration of chorine
Council predicts that this tank will need to be filled approximately 5 times a year if the full
200ML is treated
The chlorine bonds to any organic matter in the water which will make it easier for the
particle filter to remove the organic matter later in the treatment train
The dosing system should leave a chlorine residual level of 1 mg/L.
Particle Filter 1
Particle Filter 1 is a screen filter that has a 200 micron screen. This filter will remove particles greater
than 200 microns that carry pathogens, nutrients and heavy metals.
This filter has an automatic backwash system that self-cleans the filter when there is a buildup of
particles that reduce the performance of the filter. The backwash is directed into the sewer. Figure 5
below provides an indication of how the water treatment system works.
3
4
6
1
2
5
Figure 5: The first phase treatment system.
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The first phase treatment system is located between the wetland pump and the AFL tanks. The blue
line/arrow indicates the direction of flow in the system and the orange arrow indicates water after
final treatment being delivered to the storage tanks (read next section for more information). Below
is a description of the components numbered:
12345-
The chorine dosing system
A water meter that records the total volume of water harvested
Particle filter 1
A water quality monitoring point
A gauge that sends information back to the chlorine dosing system that indicates the level of
residual chlorine – the system automatically increases or decreases dosage to achieve the
desired level of residual chlorine.
6- A bypass pipe section that misses the filter (mainly used for commission to determine if filter
is working – i.e. a water sample using the filter and not using the filter).
After the particle filter the water is stored in a series of tanks in the AFL precinct. These tanks can
store 800KL of water and are the supply point where the Sydney Water potable supply enters the
system if there is no water being supplied from the stormwater harvesting system. Therefore there
are two sets of float switches that trigger the system to either start supply or stop supply within
these tanks, for both the potable water and the harvested stormwater.
2.3.4.2. SECOND TREATMENT PHASE
When there is a demand for water, either from irrigation of the AFL grounds or to fill a tank at one of
the reserves, the water is gravity feed back into the pump shed. The water is pumped through the
system using a series of pumps. Each pump has a flow rate of up to 11 litres a second and uses
variable speed drives. These pumps maintain pressure within the distribution line and irrigation line.
Before the water is pumped out of the AFL shed it is treated via the following.
2.3.4.2.1.
Particle Filter 2
Particle filter 2 is another screen filter that removes all particles greater than 100 micron. This filter
is important as any particles greater than 100 micron can block the sprinkler heads and the smaller
the particle size the more effective the UV filter will perform.
This filter has an automatic backwash system that self-cleans the filter when there is a buildup of
particles that reduce the performance of the filter. The backwash is directed into the sewer.
2.3.4.2.2.
Ultraviolet (UV) disinfection unit
A UV disinfection unit is used to remove any pathogens that have survived the chlorination system.
o
o
o
UV disinfection units remove pathogens in the water as the UV energy penetrates the outer
cell membrane, passes through the cell body and disrupts its DNA preventing reproduction.
One of the key benefits to UV disinfection units is that UV treatment does not alter water
chemically and that there is nothing added to the water and you only need electricity to run
the unit. Therefore there is minimal maintenance required.
One key factor that impacts the performance of UV disinfection is the turbidity level of water.
A turbidity level of greater than 5 NTU will reduce the effectiveness of the UV radiation from
hitting the pathogen as it could be shielded by the particles there not being treated. Hence
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
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why it is so important to have a filter that removes particles before the water reaches the UV
disinfection unit.
2
4
1
3
5
Figure 6: The second phase treatment system.
The treatment system after the AFL tanks before irrigation and distribution. The blue line/arrow
indicates the direction of flow in the system. Below is a description of the components numbered:
1- The water enters the system from the AFL tanks via gravity to the pump station (pipe
unseen).
2- The 3 pumps that will distribute the water to the other tanks/irrigate the AFL grounds. (1
pump was installed as part of the scheme and other 2 already existed). The white boxes on
top are the variable speed drives.
3- A pressure vessel to assist in the maintenance of pressure in the distribution line.
4- Particle filter 2.
5- UV disinfection unit.
Once the water has received its final treatment the water is either used to irrigate the AFL grounds
or is stored in one of the 7 additional tanks built by the scheme. The tanks are located in the
Sportspark (4 tanks including one each for baseball, softball, athletics, and soccer), Anne Aquilina
Reserve, Kareela Reserve, and Nurragingy Reserve to be used for watering the sporting fields and for
flushing toilets located at these facilities.
Figure 7 below illustrates the set out of the treatment system in the AFL pump room. Starting from
the top right to the middle left and then from the bottom left to middle top.
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Figure 7: A diagram of how the AFL pump room treats the water.
Control of the system
Council has commissioned the installation of a SCADA (Supervisory Control and Data Acquisition)
system, which is a computer system that gathers and analyses real time data to control the whole
system. All of the pumps, monitoring equipment, disinfection units, tank/storage levels and filters
send information to the SCADA system that stores the information, sends the information to a server
in Council (every 5 minutes), and can perform analysis to determine faults or issues with the system.
If an issue occurs it will send alerts to the officer responsible for management of the system, to
rectify.
The SCADA system also allows Council to remotely access the controls of the pumps and determine
the water levels in the storages. This allows the officer to remotely turn pumps on and off from their
office rather than having to go out to site (saving time and money). The SCADA system also collects
data on the volume of water produced by the scheme and the amount of electricity used by the
scheme.
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Photo 11: The SCADA system with computer interface.
2.4.
Project status
Currently the scheme has been built and commissioned. Council is currently monitoring the quality
of the water produced by the scheme to ensure that it meets the Australian guidelines for water
recycling and provides consistent results. Once this occurs the scheme will be officially turned on for
use.
Once the scheme is fully operational Blacktown City Council will manage the scheme for a further 6
to 12 months collecting data on operational and maintenance costs to determine how the scheme
will be managed in the long term. In the long term the scheme will either be managed in-house by
Blacktown City or managed by a private operator. Under both management systems, the user of the
water (Blacktown City or Blacktown Venue Management) will be billed per KL of water used, similar
to Sydney Water, except if the private operator was chosen they would pay a dividend back to
Council for asset hire. If Blacktown City is to manage the system the users of the water will be
charged per KL used and the funding generated will be used for maintenance, operation, and
replacement of all assets acquired for the scheme. The main objective of the management will be to
make the scheme financially sustainable, as it will not rely on external sources to maintain its
operation and maintenance. If the scheme generates a surplus, this money will be reinvested into
the scheme to improve efficiencies (i.e. increasing the storage sizes to increase demand met), supply
the water to another user (potentially external to Council), or to build a new scheme elsewhere.
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3. PROCESS AND METHODS
3.1. Project governance: (e.g. steering committee, project team and key stakeholders)
After the managed aquifer recharge project was cancelled and the Australian Government agreed on
the new above ground stormwater harvesting project a steering committee was established. This
steering committee included officers from the following Council departments:
-
Asset Design
Asset Construction
Civil and Open Space Maintenance
Natural Areas
Sport and Recreation
Blacktown Venue Management (operator of the Sportspark).
And external stakeholders the Western Sydney Parkland Trust (NSW Government).
The Steering Committee meeting were held every 2 to 4 weeks during design and every 4 to 8 weeks
during construction. The steering committee discussed components of the project such as:
-
System design
Suitability of site
Maintenance and operation
Safety (WHS)
Risk assessments
Construction staging and progress
Procurement etc.
The main project team included:
-
Catchment Projects Officer
Waterways Rehabilitation Officer
Senior Drainage Engineer
Senior Construction supervisor.
3.2. Project activities and conduct
This project has followed Blacktown City Council’s strict procurement protocols. All quotes were
approved by either the Manager of Asset Design or Director of City Assets and all tenders were
approved in Council meetings.
Tenders included:
-
System Design – Parsons Brinkerhoff (PB) Pty Ltd was awarded the contract for scheme
design using the Local Government Procurement Panel. PB designed the majority of the
scheme including all open water storages, creek works, pump stations, and provided tender
requirements for the Mechanical and Electrical tender. PB also developed the REF and
assisted with acquiring the approvals from the NSW office of water as well as construction
supervision.
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-
-
-
Mechanical and Electrical – which included the supply, installation and commissioning of all
pumps, monitoring equipment, electrical connections, communications and data storage.
The contractor that provided these works was Itech Corporation Pty Ltd and subcontractor
Neverstop Water Harvesting Pty Ltd.
Construction – the construction of the different civil components were conducted by 2
contractors that performed the works under Council’s Civil Construction Tender of rates. The
contractors that completed the works were Jay and Lel Civil Contractors Pty Ltd and J and G
Excavations and Asphalting (NSW) Pty Ltd.
Vegetation installation and maintenance – the scheme required extensive planting and
maintenance works of the harvest storage ponds and treatment wetland. Dragonfly
Environmental Pty Ltd performed these works and was procured through Council bushland
regeneration and revegetation tender schedule of rates.
Other major contracts included:
-
Installation of floating wetlands – Harris Environmental Pty Ltd;
Smart meter installation – Watersave Pty Ltd;
Installation of distribution pump and other fittings – Neverstop Water Harvesting Pty Ltd;
Water quality risk assessment – Water Futures Pty Ltd;
Water quality laboratory analysis – SGS Australia Pty Ltd; and
Construction and supply of the tilting weir - Australian Water Engineers Pty Ltd.
Blacktown City Council plant nursery provided all the plants for the project.
3.3. Water quality management
The scheme is collecting polluted stormwater from an urban creek and runoff from the Sportspark.
The main pollutant that is of particular concern to the health of the users of the sport facilities is the
total pathogen content of the water. During the water quality risk assessment completed by Water
Futures Pty Ltd a number of risks were raised and a number of solutions to these risks were created
and installed. To meet the required standards for irrigation and flushing toilets set by the Australian
Guidelines for Water Recycling this scheme is treating the polluted stormwater via the following
treatments:
-
Detention time in ponds of over 72 hours = 0.5 to 2 log reduction
Detention time in wetland of over 48 hours = up to 2 log reduction
Chlorine dosing = 2 to 6 log reduction
Particle filters (improves effectiveness of UV filter)
UV filter = 2 to >4 log reduction
Total log reduction range = 6 to 14
Overall the scheme has been designed to treat the water for unrestricted access as there will be
occasions when the maintenance staff might be in direct contact with the water by hand watering
the fields and by irrigating when there are users on site. For this reason the water quality
management plan has been developed and training will be provided to all users of the water. This
training will establish safe work instructions and provide information of when and where the water
is to be used.
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There is also going to be substantial amounts of signage warning the users of the facilities that the
irrigation water is not potable water and should not be consumed.
3.4. Stakeholder and Community Consultation
During the design phase of the project Council consulted heavily with the Western Sydney Parklands
Trust. The Trust own some of the reserves that will be supplied treated stormwater for irrigation
(Council leases these areas from the Trust) and the distribution line crossed over their land. The
Trust agreed to the project and believes that securing an alternative supply of water is beneficial to
the survival and longevity of the sporting fields. The Trust are also going to consider using the
harvested stormwater as an irrigation supply for future sporting fields being developed to the south
of Anne Aqualina Reserve.
Council also visited a meeting of the Blacktown and District Environment Group to discuss the
project. At the meeting Council presented its intentions of using the existing infrastructure and
assets at the BISP for the project. The group agreed that the project had merit and can be seen as
having a positive impact on the environment and the significant bushland located next to the BISP.
During 2013 Council conducted a community consultation forum in regards to catchment
management in the Angus Creek catchment area. During the forum Council Officers indicted that the
scheme was to be built in the near future and the community were very supportive of the idea and
believe it should be occurring more often throughout the LGA.
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4. PROJECT ASSESSMENT
4.1.
Objectives and key performance indicators
The key objectives of the project are to:
1. Provide a secure ‘fit-for-purpose’ water supply to significantly reduce reliance on drinking
water for irrigation use at Blacktown International Sports Park, Anne Aquilina Reserve,
Kareela Reserve, Nurragingy Reserve and Charlie Bali Reserve:
The scheme is delivering on this objective as it is supplying ‘fit-for-purpose’ water to all the reserves
listed above. The water is to be used for irrigation and toilet flushing at these facilities. For the water
to be fit for purpose Blacktown City ensured the scheme would provide high quality water by using
both chlorination and a UV filter to remove pathogens that are harmful to human health.
2. Identify that the stormwater quality and volume is sufficient to ensure long-term
sustainability of Blacktown International Sports Park’s revenue generating and
employment activities and for environmental flows:
Extensive modelling of the volume and quality of stormwater produced by the scheme has been
undertaken as part of the design of the scheme. This modelling, when excluding base/environmental
flows in Angus Creek (above 10 litres per second) estimated that in an average rainfall year the
security of supply is approximately 85%. During a dry period the scheme should still produce 73% of
the demand.
It is also predicted the price of the harvested water would cost less than the potable water supplied
by Sydney Water. Therefore Blacktown Venue Management (the operator of the Sportspark)
revenue will increase as less funding is being spent on potable water which will increase
employment opportunities as there will be more funding available for maintaining and upgrading
facilities.
3. Promote the development and sustainable use of alternative water supplies in the urban
environment through education and dissemination of project information;
The scheme has developed education material in the form of an information brochure that is
distributed during community events and on Council’s website. Additionally there will be
interpretive signage installed in the Sportspark and throughout the Angus Creek catchment to
inform the residents that the catchment is now a stormwater supply catchment for irrigation.
Blacktown City has also delivered a report at the Institute of Public Works Engineering Australasia Sustainability in Public Works conference in Tweed Heads July 2014 and the NSW Stormwater
Industry Association conference in Canberra July 2014. The report titled “Improving an urban creek
by taking the water away” (Birtles et al, 2014) describes how Blacktown City Council is potentially
going to improve the condition of Angus Creek Downstream of the harvesting point by removing the
harmful peak flows that cause erosion and flush biota and habitat downstream. Council plans on
presenting the finding of the project once real data on the performance of the scheme is collected.
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4. Maintain environmental benefits through integrated water cycle management and water
sensitive urban design (WSUD):
The scheme will have an integrated water cycle management plan developed before the scheme is
in full operation. This plan will highlight how the scheme is to be managed to maximise harvesting
potential, improving water quality when possible, and outline potential opportunities to improve the
performance of the scheme.
5. Advocate and address climate change:
Predictions for the impact of climate change on Western Sydney suggest that the temperature will
on average be hotter with a higher frequency of days above 40 degree Celsius and longer draughts.
This scheme addresses the need to have an alternative water supply when there is a drought
allowing Blacktown Venue Management and Council Officers to irrigate the sporting fields even
when water restrictions apply.
6. Sustain Council’s natural and constructed assets and maintain desired level of service
provision:
The scheme is to collect revenue by billing the users of the water and ring fencing this funding for
maintenance of the assets created by the project. The predicted funding to be generated by the
scheme will allow maintenance of the assets (both natural and constructed) to the desired level of
service and allow for replacement of assets once they require replacement.
7. Promote improved water equity.
The water being harvested by the scheme can be used by any of the reserves as long as there is
water available. No reserve will receive a benefit over another.
4.2.
Project finance
This section provides information about the funding received and expenditure as part of both the
managed aquifer recharge scheme and the current scheme. Over the length of the project the main
funding sources were from the Australian Government from the National Urban Water and
Desalination Plan grant, the Environmental Stormwater Management Program from Blacktown City
Council, and the Waste and Sustainability Improvement Program grant from the NSW Government.
Overall the scheme received $6,028,289 in funding and has currently spent $5,357,306.
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Money coming in via grant and Environmental Stormwater Management Program is provided in
Table 1 below. Please note that GRANT refers to the Australian Government grant funding, WASIP
refers to the NSW Governments Waste and Sustainability Improvement Program grant, and ESMP
refers to Blacktown City Councils Environmental Stormwater Management Program.
2010/11
$130,000
WASIP
ESMP
GRANT
TOTAL
$130,000
2011/12
$143,000
$305,000
$477,900
$925,900
2012/13
2013/14
2014/15
$730,000
$316,500
$1,046,500
$1,170,000
$1,118,100
$2,288,100
$1,337,789
$300,000
$1,637,789
TOTAL
$273,000
$3,542,789
$2,212,500
$6,028,289
Table 1: The funding allocated to the project from 2010 to 2015.
Expenditure from these funding sources, including financial years, includes:
Expenditure
Grant
TOTAL
$43,248
$43,248
$282,829
$282,829
$57,893
$533,249
$591,142
$716,530
$2,119,963
$2,836,493
$1,629,671
$300,000
$1,929,671
$2,346,201
$2,419,963
$4,766,164
TOTAL COMBINED
$265,065
$2,879,741
Table 2: The expenditure of funding from 2011 to 2015.
$ 2,212,500
$ 5,357,306
MAR Scheme
2011/12
2012/13
Sub Total MAR
Scheme
Surface Scheme
2013/14
2014/15
Sub Total Surface
scheme
WASIP
ESMP
$57,893
$207,172
$265,065
The project has therefore been built within budget.
Grant funds and WASIP funds have been completely expended. There is still $670,983 from ESMP
funds to be expended. Current commitments total $60,937 and include:






$5,043 GHD for biological water quality monitoring;
$5,063 Parsons Brinckerhoff for modelling of different maintenance performance standards;
$2,256.36 Water Save Australia for supply and installation of SMART Water Meters;
$68.09 Bunnings for rainwater harvesting wireless water level guage;
$12,976.42 SGS Australia for physical and chemical water quality monitoring; and
$35,530 Dragonfly Environmental for wetland plants establishment and maintenance.
Note Council in 2014/15 allocated funds into the ESMP account for future commissioning and
maintenance activities.
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4.3.
Potable water savings achieved by the project
The Scheme has the potential to harvest 200ML from Angus Creek plus the runoff collected from the
Sportspark sporting grounds. But this total is reliant on the end users and the amount of rainfall
received during the year.
4.4.
Levelised cost of water supplied as a result of the project
In this report the levelised cost of water supplied by the scheme is calculated by dividing the cost of
operating and maintaining the scheme, including asset renewal, by the amount of water produced
or saved. This excludes the capital costs. It is predicted that the cost to maintain and operate the
scheme would be $358,250 per year. If the scheme can produce 200,000KL this means that the
levelised cost water is $1.79/KL.
If not all 200ML is harvested this makes the water more expensive as only 0.5% of the operation and
maintenance cost is variable with the amount of water harvested, including electricity and chlorine.
It was been worked out that the scheme only becomes financially better off than using Sydney
Water when 165ML of stormwater is harvested, see the graph below.
$8.0
Average cost of harvested water in dollars/KL
average cost in dollars per KL
$7.0
$6.0
$5.0
stormwater harvesting
dollars/KL
sydney water dollars/kL
$4.0
$3.0
$2.0
$1.0
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
$0.0
ML harvested per year
Figure 8: A graph indicating the cost of harvested stormwater in relation to Sydney Water.
This cost above only takes into account Sydney Water usage charge and doesn’t include the sewer
usage charge and the other fixed charges. The predicted cost of using 200ML of Sydney Water
potable water supply including all service charges is approximately $686,400, under the stormwater
harvesting scheme it will only cost $357,120 creating a saving of $329,280. But as the scheme is not
supplying 100% of the water demand it will still rely on Sydney Water for at least 5 % of the demand,
therefore the fixed charges are still required as the Sydney Water supply can’t be disconnected.
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If the cost of potable water increases the cost savings produced by the scheme would increase.
The predicted operation and maintenance cost is estimated using a 20% contingency and the largest
cost is the removal of sediment from the open water bodies. If the sediment can be recycled or used
elsewhere instead of being disposed of in a waste facility it would save approximately $100,000 from
the maintenance budget, which will bring down the cost per KL significantly.
4.5.
Amount of GHG emission offset
The greenhouse gas emissions resulting from the operation of the scheme have been evaluated. The
use of electrical pumps to transfer water between the site of the offtake, to the treatment systems
and for distribution around the park will be the primary source of emissions. Estimations of the
pump power requirements have been made on the basis of calculated flows, calculated heads
(including system head losses) and pump efficiencies obtained from the manufacturers. Based on
the expected average yields, the total estimated average annual energy requirements for the
operation of the pumps is 42,745kWh per annum.
The National Greenhouse Accounts Factors workbook (Department of Climate Change, 2014),
provides Scope 2 emission factors for the consumption of electricity for each state. For NSW, each
kilowatt hour (kWh) results in Scope 2 emissions of 0.86kg CO2-e. On this basis, the emissions
associated with the pumping for the scheme in an average year are estimated to be 36.76t CO2e/annum.
The emissions estimated above only account for the pumping energy requirements, and it is
recognised that there will be additional energy requirements to power the instrumentation and
controls associated with the scheme. However, the power requirements for these are relatively
small. Blacktown City Council will offset the greenhouse gas emission produced by the scheme
through installing solar panels, which result in zero operational greenhouse gas emissions.
Maintenance of the scheme will involve regular (monthly) inspections and will therefore contribute
(albeit in a small way) to Council’s greenhouse gas emissions associated with the use of a vehicle to
inspect the sites. Assuming that the Council uses diesel vehicles, with an average fuel efficiency of
15L/100km (worst-case scenario) and that each lot of monthly inspections involves a maximum of
50km driving, the total fuel usage for maintenance purposes is estimated to be 90L/year.
The National Greenhouse Accounts Factors workbook (Department of Climate Change, 2009),
provides Scope 1 and Scope 3 emissions for the combustion of fuel for transport purposes. The
stated energy content of diesel is 38.6GJ/kL, with total emissions of 74.5 kg CO2-e/GJ. On this basis,
the emissions arising from the monthly inspections of the sites are estimated to be 207.1kg CO2-e
/annum.
These emissions will be offset by the planting of trees around the sites to maintain community
amenity and provide shade over the wetland to minimise evaporative losses. The carbon offset
gained by the planting of trees varies depending on location, species of tree, soil type and type of
planting. Approximately 197 trees would be required to offset the emissions from the maintenance
inspections over the life of the scheme.
Analysis of the emissions associated with the scheme shows that the scheme, results in a small net
reduction in carbon dioxide emissions of approximately 567.2 t CO2-e per annum. The scheme can
result in the use of harvested stormwater for the sustained substitution of up to 200ML of water
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
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from the Sydney Water mains distribution system for non-potable use in an average rainfall year.
The scheme is essentially a carbon sink. The significantly lower emissions are a result of using the
wetlands to enhance the water quality (as opposed to energy intensive potable water treatment
plants) and relatively smaller pumping distances.
The scheme has therefore been demonstrated to be carbon negative.
4.6.
Other environmental benefits
Blacktown City Council as part of the design process has created water flow models that are showing
eco-hydrological outcomes expected for the receiving downstream environment. Council is
expecting that the data collected by the scheme will demonstrate that the creek downstream of the
harvest point at least maintains its current ecological condition with potential for improvement.
This infrastructure project is integrated into the framework of restoring natural environments. By
undertaking rigorous modeling, we estimated the pre and post development conditions of the creek
and used this to assess the impact of the project. There is however, a strong need to link the
hydrological work undertaken with a hydraulic model so that environmental flows impacts can be
better predicted. This would ordinarily be undertaken as part of environmental flows assessment
project.
Excessive stormwater flows from urban areas greatly impact the health of freshwater creeks in
Western Sydney. Knights & McAuley (2009) describe criteria for sustainable stormwater harvesting
projects. The Project was designed to harvest stormwater to irrigate sports fields to the benefit of
the local community whilst ideally also benefitting local hydrology and eco-hydraulics.
This particular approach has specific requirements to ensure success. Large storage areas and
significant pumping capacity is required to enable water to be harvested quickly from the creek
when the rainfall events occur. It is acknowledged that the sportspark site provided an excellent
opportunity for this storage as existing open water bodies were able to be excavated further to
provide immediate storage before the water is treated. In more densely urbanised areas this may
provide more challenging.
It should be noted, however, that the treated water from the scheme is being stored in a series of
seven tank locations across differing sites. This decentralised storage outcome was undertaken in
favor of demolishing a series of existing tanks to gain greater capacity in the same location. The total
volume of the seven locations is 1800kL and demonstrates a more flexible footprint that may
provide a model for providing large storage in more confined urban contexts.
Urban governments and utilities Australia wide continue to provide services for a customer base that
is increasing demanding improved liveability outcomes for their cities. This project demonstrates
that provision of ecosystem services (such as water supply) from the local environment, as opposed
to more traditional centralised supply approaches, have the ability to also liberate multiple liveability
outcomes such as improved local waterways and aesthetics for the community (Birtles et al 2013).
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5. EXPERIENCE SHARING AND LESSONS LEARNT
One of the main lessons learnt relates to construction of ponds, wetland and online creek works.
There was a considerable amount of construction required on both online creek works as well as
offline water bodies. The wet weather that occurred from December 2013 to July 2014 caused
delays and subsequently other works were than delayed. Although it was predicted that the
construction timeframe should only be 4 months it turned into 8 months. Therefore always allow for
wet weather delays when working in or near a creek. For example during construction of the harvest
storage ponds, that fill up from swales and runoff, every time there was a storm the ponds would fill
up and it would take a week to drain and another week to dry out sufficiently for excavation to
occur. One positive that came from this was it did show the effectiveness of the ponds for collecting
runoff without it being pumped from Angus Creek.
Another major lesson was the effectiveness of using a steering committee. The Steering committee
was able to work around many issues that would have not been raised until the project was
complete. This early intervention saved the project thousands of dollars in the long run and it
provided an effective means of updating all the relevant stakeholders on progress.
5.1.
Project results and outcome realisation
The predicted yield of the system was originally underestimated as the storage ponds within the
Sportspark, which are used as the main storage facility for the scheme, also collect surface runoff. As
discussed above each storm event provides water to the ponds via runoff. The ponds also collect
irrigation runoff from the AFL/cricket grounds that surround the ponds. These fields use a sandy
loam media underneath the sporting surface and any irrigation or rain that drains through the media
will be collected by the under drainage and be directed back into the ponds to be reused. This makes
the scheme more efficient as the runoff generated from the irrigation of the AFL fields is redirected
back into the storage ponds creating a cycle system. Also during heavy rain events the ponds will fill
up via the swale network without the system having to pump the water from Angus Creek saving
electricity and maintenance required on the pumps. During small rainfall events when the runoff
volume within the Sportspark is minimal the Angus Creek pumps will transport water from the
offtake pool into the storage ponds.
5.2.
Major project issues
One major project issue related to the design of the system, in particular the site constraints within
the Sportspark. The project could not expand the existing ponds or wetlands due to the site having
limited space available and due to future plans for the expansion of sporting facilities. If the project
was allowed to expand the harvest storage ponds it would have increased the overall capacity of the
scheme to harvest more stormwater. The design of the ponds and other features required a number
of reviews and extensive consultation with the managers of the Sportspark and other users.
Another major project issue was related to acquiring the required approvals from the NSW Office of
Water. Blacktown City Council first had to seek approval to construct the creek works that diverted
water from the creek into the offtake pool. This approval process, although drawn out (over 6
months to approve plans), was satisfactory and Council acquired the required works approval. Once
the works approval was granted Council was also required to purchase “Unit Shares” from the Lower
South Creek Management Zone to extract stormwater for the scheme which was set out in the
Water Sharing Plan set out in the Water Management Act 2000. One unit share is equivalent to 1
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Megalitre (1 million litres or ML) of water from the creek, therefore Council was required to contain
200 unit shares and attach them to the current water extraction license held by Council. To acquire
these unit shares Council produced and ran a tender that was advertised in several local papers
promoting that Council was willing to purchase any excess or unwanted unit shares that land owners
within this particular management zone might have. The tender ran for 4 weeks yet no one
submitted a response. The privacy policy within the NSW Office of Water restricted Council from
accessing license holder information and therefore finding license holders without spending a large
quantity of funding was impossible. Instead of the NSW Officer of Water assisting Council in finding
license holders a decision was made by the NSW Office of Water to exempt Council from purchasing
the unit shares all together. This process was unsatisfactory as Council was forced to spend
considerable time and funding into tendering and modeling to show that the scheme was actually
benefiting the environment through reduced peak flows and improvements in water quality.
Forcing local governments and other water supply authorities that are willing to harvest stormwater
from an urban creek to purchase unit shares will potentially make any stormwater harvesting and
reuse project financially unfeasible. Unit shares regularly sell in other management zones for
approximately $1,000 to $1,500 per share. Therefore if this scheme was forced to purchase the unit
shares it could have added $200,000 to $300,000 to the overall cost of the scheme which may have
made the project financially unfeasible. It is Blacktown City Council’s perspective that the NSW
Office of Water should consider modifying the water sharing plans or the Water Management Act
2000 to permit harvesting from urban creeks without having to purchase unit shares as long as base
flow is not harvested and the downstream environment is considered. There are considerable
benefits that can be made to the condition of urban creeks by removing some of the damaging flows
that are created in small to medium rain events. This scheme is also conducting extensive
monitoring of upstream and downstream environments to prove whether this scheme is going to
have a positive or negative impact to downstream environments in the long term. From research it is
predicted it will have a positive impact but little detailed research has occurred regarding
stormwater harvesting in Sydney.
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6. PROJECT FUTURE
The scheme is currently in the verification phase where the water quality is being monitored to
ensure it meets the correct standards so it’s fit for purpose. This phase is predicted to take 3 months
and the scheme should be fully operational before September 2015.
Blacktown City Council Design and Development section will maintain the scheme for a period of at
least 12 months post verification (that is 2015/16 financial year). The manager of the scheme will
use both Blacktown City Civil and Parks Maintenance staff and specialist contractors to maintain the
scheme to ensure the water is fit for purpose and all components are maintained properly. At the
same time data will be collected on scheme performance, operation and maintenance costs, time
required for management etc. This will provide background data so that Council can make decisions
on how the scheme is to be maintained in the long term.
After this initial maintenance period Council will need to make a decision on whether the scheme
should be maintained in-house (business as usual) or if an external company (private water
authority) is engaged to maintain the scheme in the long term. There are benefits and disadvantages
for both maintenance models.
Regardless of who maintains or operates the scheme there will be an annual report to Council
providing details about revenue raised, allocation of funding, scheme performance, elements to
improve, and recommendations.
Blacktown City Council is currently planning on building more stormwater harvesting and reuse
schemes as the benefits of these schemes are being realized. With the cost of potable water set to
increase Council is realizing the economic, environmental and social benefits gained by using
stormwater harvesting over potable water.
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7. CONCLUSIONS
The Blacktown Stormwater Harvesting and Reuse Scheme will provide a sustainable fit for purpose
water source for the Sportspark and surrounding reserves. This scheme has also acted as a pilot
project for Blacktown City Council to consider the feasibility of further integrated water
management projects that improve water quality and hydrology thorough water harvesting and
reuse.
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ATTACHMENTS
Audited financial statements prepared in accordance with Australian Accounting Standards
Blacktown Stormwater Harvesting and Reuse scheme – Final Report
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