Eastern Melbourne Parks and Gardens
Stormwater Harvesting Scheme
Final Report
31 August 2013
Report Clearance
Function
Position
Name
Signature
Date
Prepared by
WSUD
Ralf Pfleiderer
4/9/2013
Team Leader
Eamonn
4/9/2013
Parks Planning
Fennessy
Manager Urban
Ian Shears
5/9/2013
Director City
Prof. Rob
06/09/2013
Design
Adams
Coordinator
Reviewed by
Landscapes
Approved by
2
Contents
Executive Summary ................................................................................................................. 5
Project overview ................................................................................................................... 5
Project results and outcome realisation ................................................................................ 5
Major project issues .............................................................................................................. 5
Timing ............................................................................................................................... 5
Funding ............................................................................................................................. 5
Soil management and services.......................................................................................... 5
Events ............................................................................................................................... 5
Project Overview ...................................................................................................................... 6
Project background ............................................................................................................... 6
Project objectives and goals ................................................................................................. 7
Project conditions ................................................................................................................. 7
Project commencement and completion dates, project duration ........................................... 8
Project scope/deliverables and high level milestones............................................................ 8
In-Scope Activities ................................................................................................................ 9
Out of scope Activities .......................................................................................................... 9
Funding sources ................................................................................................................. 10
Process and Methods ............................................................................................................. 10
Project governance ............................................................................................................. 10
Steering committee ......................................................................................................... 10
Manager Capital works .................................................................................................... 11
Project manager .............................................................................................................. 11
Project Implementation Group ......................................................................................... 12
Project activities and conduct.............................................................................................. 12
Greenhouse Gas emission offset ........................................................................................ 12
Water quality management ................................................................................................. 13
Stakeholder consultation, community engagement, information community and key
promotional/public activities ................................................................................................ 13
Project issues/risks and measures/management ................................................................ 14
3
Project Assessment ................................................................................................................ 15
Achievement of project deliverables and outcome realisation ............................................. 15
Fitzroy Gardens ............................................................................................................... 16
Birrarung Marr ................................................................................................................. 18
Alexandra and Queen Victoria Gardens .......................................................................... 19
Project finance .................................................................................................................... 22
Volume of stormwater harvested and potable water savings............................................... 22
Levelised cost of water supplied ......................................................................................... 22
Amount of GHG emission offset and/or energy saving achieved ......................................... 23
Other environmental benefits .............................................................................................. 23
Social benefits .................................................................................................................... 23
Summary of outcome realisation and its extent ................................................................... 25
Experience Sharing and Lessons Learnt ................................................................................ 26
Project Future......................................................................................................................... 27
Proposal for project handover, operation, maintenance and ongoing monitoring ................ 27
Remaining tasks or any outstanding work going past the funding agreement ..................... 27
Conclusions and recommendations ........................................................................................ 28
Attachments .............................................................................. Error! Bookmark not defined.
4
EXECUTIVE SUMMARY
Project overview
The Eastern Melbourne Parks and Gardens Stormwater Harvesting Scheme will deliver
alternative, fit-for-purpose water for irrigation of public open space that will reduce demand for
and reliance on potable water. The scheme was co-funded by the Commonwealth
Government through the Water for the Future program. The three individual projects that make
up the scheme are located in Fitzroy Gardens, Birrarung Marr, Queen Victoria and Alexandra
Gardens. These are all prominent and highly valued public open spaces and will provide a
significant social educative contribution in making stormwater harvesting visible for the
community.
The project construction was completed in August 2013. The commissioning of the projects
has commenced and will be ongoing into the irrigation season to ensure all features work
effectively and that the integration with the existing irrigation control system is seamless.
Project results and outcome realisation
The scheme has resulted in the following outcomes;
-
The three projects are projected to replace 119 million litres of potable water that was
previously used for landscape irrigation;
-
Improved long-term health and enhancement of the surrounding landscapes.
-
Reduction in stormwater pollutants; and,
-
Education and increase public awareness opportunities of stormwater management
Major project issues
Timing
The design for each system was complex and required input from a number of specialists. The
design had to be resolved sufficiently to enable accurate pricing by tenderers and avoid issues
during construction. This required more time for each project than anticipated.
Funding
Due to the number of unique elements contained within the project costs were uncertain until
the tenders were awarded.
Soil management and services
Soil conditions are highly variable and not well documented within our parklands. The risk was
minimised in these projects by conducting the detailed investigation prior to construction and
adjusting the design as required.
Events
Each project is located in highly visible and heavily used spaces both for general park visitors
and significant organised events. Through considerable stakeholder management during the
design and construction phase impacts were minimised.
5
PROJECT OVERVIEW
Project background
Melbourne is a city well known for its beautiful parks and gardens which attract more than 12
million visitors each year. The municipality contains approximately 560 hectares of open space
including 65,000 trees and nearly 480 hectares of internationally acclaimed parklands, all
requiring year-round maintenance and management.
The City of Melbourne is responsible for the management of these important green spaces, a
responsibility that has been challenged by the combined impact of climate change, drought
and water restrictions. Melbourne experienced 13 years drought following its onset in 1997.
The drought broke in 2010 with the city receiving above average rainfalls. However soil
moisture levels remained sub-optimal in many areas of the city, particularly below the top
200mm.
The City of Melbourne’s planning for climate adaptation of parkland has focused on landscape
adaptation strategies, identifying and securing alternative water sources, and improving park
management techniques. As a result of a variety of water management measures put in place,
in 2007 use of potable water for maintenance of City’s public open spaces and trees was
reduced by 62 per cent (from the agreed baseline year of 2000). Such a level of reduction,
while demonstrating a commitment to comply with water restrictions, did not provide for the full
irrigation requirements of the City’s landscapes. In fact, it has accelerated the decline of many
of our older trees. Therefore, a new approach that focuses on efficient as well optimum levels
of irrigation for vegetation health has been adopted. Alternative water sources will form a key
part to ensure water security and maintain Melbourne’s parklands to a high level of amenity,
environmental service provision and horticultural standard.
City of Melbourne’s drought proofing initiatives for parks and gardens includes the
investigation of possible opportunities to capture, treat, store and reuse stormwater from urban
catchments. This draws on conceptual modelling undertaken for a number of projects,
including the ‘Total WaterMark – City as a Catchment’ (2008) strategy.
Heritage landscapes such as Fitzroy Gardens are of particular concern given the impact that
water restrictions can have on the amenity, character and health of older significant
landscapes and established trees. Similarly, heavily used events oriented parks and gardens
such as Alexandra Gardens and Birrarung Marr bring additional pressure on parks
management strategies.
These three high profile parkland areas, all located in the eastern portion of Melbourne’s
famed ‘emerald necklace’, make a significant contribution to the character and liveability of
Melbourne as well as representing a high cultural, economic, social and environmental value
to the City. For this reason they have formed the focus of investigations to secure an
alternative water supply for their ongoing irrigation needs. Meeting these needs regardless of
the impacts of climate change, drought and water restrictions will ensure the future of these
important landscapes is secured for Melbourne’s residents, workers and visitors.
City of Melbourne undertook functional designs for stormwater harvesting schemes located in
the Fitzroy Gardens, Alexandra Gardens and Birrarung Marr. Each park’s system captures
stormwater from surrounding catchments for use as landscape irrigation within the park.
Horticultural ‘demand side’ analysis of each park’s irrigation requirements has been
undertaken to provide a sound basis for estimating the amount of water required to maintain
the health and amenity of each specific landscape. The objective of each project is to prioritise
6
the health of these precious city parklands while minimising the amount of potable water
applied.
Each system’s primary function is to deliver year round treatment and harvesting of
stormwater for use as non-potable landscape irrigation. Alongside this, each project is
designed to play a role in enhancing the general public’s awareness of the potential to
undertake sustainable initiatives involving infrastructure and water supply even in sensitive
heritage listed parkland. The profile and annual visitation rates of the parks involved will
enable these positive environmental messages to be spread widely throughout the community.
Each project will also deliver significant environmental outcomes to the receiving Yarra River
by decreasing peak runoff from rain events and reducing inputs of sediments and nutrients
which are detrimental to the health of Melbourne’s Port Phillip Bay.
Project objectives and goals
The following goals were defined for the scheme in the funding agreement with the
Commonwealth Government:
1)
Replace 124 ML/year of potable water by using treated stormwater to irrigate Fitzroy
Gardens, Birrarung Marr and Alexandra Gardens over a five-year rolling period;
2)
Ensuring landscape health by providing a reliable, fit-for-purpose alternative water
source for these significant heritage gardens that is independent of future water
restrictions;
3)
Reduce nitrogen, sediment, phosphorous and heavy metals entering the Yarra River
and Port Phillip Bay thereby helping the City of Melbourne achieve its stormwater
quality improvement targets; and
4)
Maintain or enhance existing landscape values thus having no significant impact on
current garden use post construction;
The following additional objectives were included internally;
5)
Deliver the scheme within known and agreed budgets, time frames and quality
parameters;
6)
Manage project risks appropriately including health and safety risks and environmental
compliance;
7)
Through community engagement and education, increase the public’s connection with
and understanding of stormwater management and water conservation for large
landscapes.
Project conditions
The following constraints have affected the projects;
a) The projects are located in parklands that are very popular, with space at a premium.
Proposed solutions needed to have the minimum footprint possible, be hidden,
underground or well integrated into the existing landscape.
b)
The sites all have a large number of stakeholders that required regular updates or
direct involvement.
c)
The construction and ongoing operation within 24 hour publicly accessible parklands,
which are also frequently used for events both large and small, placed significant
constraints and influence on design parameters, construction methodology and access.
7
d)
The proposed stormwater inception points are located on large, old and operational
storm water drains. Additionally, the Birrarung Marr diversion point is only 10 meters
from the outflow point to the Yarra River. These conditions imposed some
constructional constraints where tides, storm events and the structural integrity of the
existing infrastructure had to be kept in mind. Bypasses where also difficult to arrange,
therefore existing drains had to remain active during construction.
e)
Another condition that influenced the design was the fact that the stormwater runoff
feeding the projects comes from highly urbanized catchments which contain major
roads, busy trams routes and businesses within close proximity to the CBD.
The following assumptions were also made when developing the scope of works:
1.
Each project will be tendered as a single works package
2.
Funding for each project is limited to the amount approved in the budget
3.
The Fitzroy Gardens stormwater harvesting project will form one part of the greater
depot rationalization project
4.
Soil contamination is likely at each site and the City of Melbourne will need to be
innovative to limit disposal costs
5.
That the industry is able to deliver a number of large scale stormwater harvesting
systems in the greater Melbourne area within a relatively tight time period before early
2013.
Project commencement and completion dates, project duration
The project formally commenced with the execution of the funding agreement in May 2011.
Prior to this the City of Melbourne further refined the functional designs, conducted soil tests
and revisited conceptual design intents where soil conditions were not favourable to the
proposed design layouts. The design, consultation and construction for the three projects have
taken 2 years with construction completed in August 2013. Commissioning of the systems will
be ongoing for the next 6 months to refine the automated control systems.
Project scope/deliverables and high level milestones
The high level Milestones for each project included;
 Design, documentation and consultation ready for public tender
 Public tender process including council approval
 Construction of the storages
 Construction of the secondary treatment system
 Construction of the diversions and primary treatment elements
 Construction and connection of the irrigation system
 Commissioning of the systems including the automated controls
8
In-Scope Activities
Description
Appointment and management of consultants and contractors
Integration with the existing irrigation systems at each project location including any
upgrades required for system functionality
Construction of items shown in the tender drawings and specifications (when
produced)
Testing and commissioning
Management and supervision activities directly associated with the project
PCG support and administrative costs
An official opening for each project as required by the funding agreement
Educational activities as required determined by the City of Melbourne and
stakeholders
Provision for training, operations and maintenance manuals and materials as
provided for by the specifications
Handover by project staff to service contractors and management
Corporate overhead charges
Out of scope Activities
The activities listed in the table below are not part of the scope of the projects as listed in the
funding agreement but may be undertaken by the City of Melbourne or other groups as the
project progresses.
Activity
Lead party / Funding
Remediation of contaminated soil
City of Melbourne
Works associated with the Fitzroy
Gardens Depot Relocation
City of Melbourne
Works associated with the new Fitzroy
Gardens Visitor Pavilion
City of Melbourne
Works associated with the creation of a
new garden area on top of the tank in
Fitzroy Gardens other than the basic
reinstatement included in the project
budget
City of Melbourne
Birrarung Marr events relocation during
construction works
City of Melbourne
9
Linlithgow Triangle landscape works
associated with road closure and
creation of new gardens area
City of Melbourne
Ongoing operation and maintenance of
the assets (other than as specified in the
contact documentation)
City of Melbourne
Promotion of the project to the
community and tourism sector, other
than allowed for in the marketing and
communications proportion of the project
budgets
City of Melbourne
Employee salaries, other than specifically
noted in the budget
City of Melbourne
Staff training
City of Melbourne
Funding sources
The scheme has received a $4.88 million grant under the National Urban Water and
Desalination Plan. The remaining funding has come from the Melbourne City Council.
PROCESS AND METHODS
Project governance
To effectively manage the design and delivery of the three projects within City of Melbourne
the following governance arrangements were made. These are standard for large projects
delivered by the City of Melbourne.
Steering committee
A Steering committee has been created including the members at director and management
level. The role of the steering committee was to:
 Provide oversight of compliance with the City of Melbourne’s contractual commitments
to its key funders

Monitor relationships with key stakeholders

Review and approve whole-of-project budget and cash flow

Review and approve the whole-of-project schedule and achievement of milestones

Review and authorise project risks and the project risk assessment

Make recommendations to the Council on significant procurement items.
10
Manager Capital works
The Manager Capital Works is responsible for the delivery of various capital works on behalf of
the City of Melbourne. The Capital Works branch comprises a team of professional project
managers. The manager provides the authority and delegation to enable successful delivery of
the project. The role encompasses:
 Monitor compliance with the Funding Agreement and any other funding agreements

Review the detailed schedule and achievement of milestones

Review the detailed budget and cash flow

Overview budgetary expenditure and schedule to provide compliance with the Steering
committee’s approved budget and schedule

Authorise Milestone reports and recommend sign-off by the Director, City Design

Approve Milestones and status reports prior to submission to the Steering committee

Confirm implementation of the health and safety co-ordination plan

Review project risks and project risk assessment

Coordinate and authorise allocation of Internal City of Melbourne resources where
required

Confirm compliance with City of Melbourne policies and protocol (including tender
process)

Oversee tender process for design activities and construction works

Guide development and implementation of the communications plan

Act as Principal’s representative for significant design contracts and construction
contracts
Project manager
The project manager is accountable for the successful delivery of the project to meet the time,
quality and cost parameters agreed with key stakeholders including DSEWPC. The role
encompasses:
 Provide management of the project in accordance with the Project Plan

Prepare Milestone and Status Reports prior to submission to the steering committee

Day-to-day management of budgetary expenditure and schedule

Day-to-day management of designers and contractors

Manage project risks and project risk assessment

Undertake tender process for design activities and construction works

Co-ordinate internal Stakeholder engagement

Co-ordinate the works with other activities occurring at close to project sites

Provide representation to external stakeholders and co-ordination with those
stakeholders to achieve required project outcomes.
11
Project Implementation Group
The project implementation group will be established for the each project and is comprised of
core City of Melbourne staff. It had representatives form the following branches:

Capital works (Project Manager)

Urban Landscapes (Parks Planner & WSUD Coordinator)

Design (Landscape Architect)

Parks Services (Open Space Contract Manager)

Engineering Services – Infrastructure

Other parties such as principle consultants and other council branches will be invited
as key issues and tasks affecting their areas are identified.
The project Implementation group will meet regularly throughout the design (weekly or
fortnightly) and construction phase to provide guidance and stakeholder management
assistance to the project manager;

Identify ways to engage the community and the media with the project and guide
development and implementation of the communications plan

Ensure designs are reviewed to achieve compliance with the design intent contained in
the funding agreement and other project commitments

Be the decision making body in relation to items of design aesthetic and integration in
the landscapes

Ensure decisions affecting the design and construction of the system are in line with
internal and external stakeholders expectations

Provide guidance for the resolution of issues in design and construction as they arise
throughout the project
Project activities and conduct
The design and construction project management was conduct in-house by the Capital Works
Branch. The design for each project was developed through the lead consultant (Cardno) to
tender documentation. A number of sub-consultants were needed to get to this point including
structural, irrigation & pump system, soil & geotechnical, electrical and landscaping.
The tender process conformed to City of Melbourne standards for public tenders. The
successful tenders where engaged directly to the City of Melbourne with in house supervision
of the contract, specifications and quality control. External expertise was engaged as
necessary to ensure the design intent and building standards were complied with.
Greenhouse Gas emission offset
The initial intent was to install renewable energy systems equivalent to the energy
consumption of the harvesting systems operation energy demand (principally the pumps). This
has been overridden by a Council decision on the 17 April 2012 to adopted the “Carbon
Neutrality - Council Operations” policy. This commits council to;
o
develop a strategy;
o
establish an inventory;
o
reduce emissions associated with Council’s activities;
o
neutralise remaining emissions (offset);
o
communicate approach and engage the community; and
o
evaluate progress and review approach.
12
Through this approach the energy emissions of the scheme will be assessed and audited and
then any emissions that remain would be off-set.
Water quality management
The quality of the water in the reuse tanks will be monitored and reviewed during and after the
completion of each project. During normal operation the water quality will be monitored on-line
for turbidity, pH and Salinity. Monitoring of other water quality constituents will also be
conducted. A detailed water monitoring strategy will be developed in conjunction with the
production of the design and construction documentation. This monitoring strategy will be
integrated into the operations and maintenance manual. As a baseline water quality samples
were taken immediately upstream of the diversion locations of each project.
The City of Melbourne has also undertaking a detailed Risk Management and Incident
Response Plan for our Royal Park Wetlands harvesting scheme. This system has been
operational for several years and provides a great opportunity to pilot this plan. We are in the
process of extending this approach to our other schemes.
The reuse water quality standard at each site complies with the Australian Guidelines for
Water Recycling - Stormwater Harvesting and Reuse (July, 2009) as well as state plumbing
standards.
Stakeholder consultation, community engagement, information community and key
promotional/public activities
The parks and gardens of the City of Melbourne are highly valued by the community, who are
passionate about them and visit regularly as individuals or groups. Fitzroy, Alexandra and
Queen Victoria Gardens as well as Birrarung Marr are an important part of Melbourne’s
tourism offering and event spaces.
These three high profile parkland areas, all located in the eastern portion of Melbourne’s
famed ‘emerald necklace’, make a significant contribution to the character and liveability of
Melbourne as well as representing a high cultural, economic, social and environmental value
to the City.
For this reason they have formed the focus of investigations to secure an alternative water
supply for their ongoing irrigation needs. Meeting these needs regardless of the impacts of
climate change, drought and water restrictions will ensure the future of these important
landscapes is secured for Melbourne’s residents, workers and visitors to enjoy.
Alongside this, each project is designed to play a role in enhancing the general public’s
awareness of the potential to undertake sustainable initiatives involving infrastructure and
water supply even in sensitive heritage listed parkland. The profile and annual visitation rates
of the parks involved will enable these positive environmental messages to be spread widely
throughout the community.
The scheme has the potential to engage stakeholders in a positive manner and to facilitate
beneficial outcomes in many segments of the community. However, any projects of this nature
and scale involve change and development. In some cases, this change may not be viewed in
a positive manner by all stakeholders
Identification and communication with Stakeholder groups was an important part of the
scheme. It is a key mechanism by which the community can learn about the scheme.
13
The scheme sort to identify and interact meaningfully with the stakeholders affected and
establish a community engagement plan that met the needs of the scheme and the
stakeholders.
The Community Engagement Plan identified internal and external stakeholders and assessed
their interest and information needs. The plan identified appropriate communications methods
and channels and assigned responsibility to individuals on the project team.
Feedback throughout the project has been favourable, even when the project interfered with
public events. Engagement has included many forms, some of which are detailed below.

Installation of 2-3 project information signs at each project location

Media event to signify the commencement of construction of the Fitzroy Gardens
Storage with the Lord Mayor Robert Doyle and Senator Don Farrell with a story
appearing on Channel 10’s evening news.

Presentations at industry conferences such as Stormwater 2012, WSUD2012, SV
Conference 2013, and the Innovative Water Management conference.

Presentations to ICLEI water campaign Victorian members, to Auchi Environment
Dept. (Japan), to Planning workshop for CRC WSC at Maddocks Lawyers, RMIT
lecture to “Contemporary Local Government” students.

The State Governments Department of Planning and Community Development
produced a video in conjunction with the City of Melbourne focussing on the Total
Watermark Strategy. This included video and information on the Fitzroy Gardens
scheme.

Site visits for where conducted for Andy Lipkis, Founder and President, Tree People
USA, Dr Robert Wilkinson, University of California, for Yarra Valley Water,
Manningham City Council, Bandung Institute of Technology (ITB) Indonesia, a high
level delegation of Indian parliamentarians, the Stormwater Victoria Annual AGM
walking tour and as part of the C40 Melbourne conference delegate walking tour.
Project issues/risks and measures/management
A project risk assessment was carried out in relation to the delivery of the scheme. The risk
assessment has been carried out in accordance with City of Melbourne Risk Management
Guidelines and ISO41000.
The following sources of risk have been used in the preliminary project risk assessment:




Financial
Human Safety
Environmental and Cultural Heritage
Reputation and Image
The risk assessment considered inherent risk, and judged the controls available to gain an
understanding of the residual level of risk for each impact. Specific risk improvement or
contingencies were implemented or monitored as appropriate.
14
The following items required particular attention;
Timing
Timelines for the project where set by the funding agreement, which required a completion
date of June 2013. The design for each system was complex and required input from a
number of specialists. This took more time for each project than expected. It was determined
that the risk was too great to go to a design and construction tender, therefore the design had
to be resolved down to the finer details to enable accurate pricing by tenderers. The benefit of
refining the design was that issue became apparent in the design phase, rather than during
construction. The problem was that it took a long time to get the project to tender, putting
pressure on the construction phase.
Funding
Until the projects where tendered and prices returned by tenderers, we were unsure of the
cost of the project as they contained a number of bespoke elements that quantity surveyor
where unable to cost. Given that the federal funding was capped, any cost over runs had to be
borne by council.
Soil management
The soils within the City of Melbourne parklands generally have a level of contamination that
requires specialist management. This required considerable investigation during design, but
also an element of unknown time and cost expense during construction. This risk was
minimised by conducting detailed investigation prior to construction and adjusting the design
as required to minimise the cost.
Events
The location of each project is high visible and within heavily used spaces both for tourist
visitors and organised events. This required considerable management and consultation
during the design phase. It also impacted on the design including shifting the location of the
storage tank within Birrarung Marr. In the end the cooperative contractors managed their sites
well during construction which provided minimal impact on the major events. The contractors
where made aware of the requirement to fence of works areas, of access restriction and nowork periods during major events (principally weekends).
PROJECT ASSESSMENT
Achievement of project deliverables and outcome realisation
The three projects have been successfully constructed. Commissioning will be undertaken
over the last half of 2013, when the control of the pumps and the integration with the irrigation
system is test, and refined.
Each project outcome is described in details below with the aid of interpretation sign and
construction images.
15
Fitzroy Gardens
The system comprises of the following components
5 million litre poured in-situ concrete storage tank divided
into a 4 million litre primary tank and 1 million litres for the
clean reuse water.
Diversion weirs in the drainage system that captures the
flows up to the 1 year ARI event. Allowing greater flows or
when the primary tank is full to overflow into the existing
drainage network.
A gross pollutant trap (GPT) that captures larger litter, like
leafs, packaging and bottles. It will also capture the larger
sand and soil particles.
A sediment chamber had been included to capture the
fine sands and sediments as well as oil and
hydrocarbons. This is to minimise the cleanout
requirement for the primary tank, which will further settle
these stormwater components.
A pump in the primary tank that delivers the water into the
Biofiltration bed at a pre-program interval. The pump will
not operate when the tank is below the low level which is
monitored by a level transducer and communicated back
to the pump controller. The full level of the tank is
controlled by the level of the diversion weirs.
The biofiltration bed is built like a regular rain gardens
with a sand filtration layer, a transition and a drainage
layer. The filter was planted with pre-grown ephemeral
wetland plants that are installed in large format blocks and
establish within a month to provide high quality water.
Where it differs is that it is flooded by water being applied
through dome shape spreader. The flooding and resting
cycle is determined by the extended detention supplied by
the height of the surrounding wall and the set point of the
overflow pit within the bed. The drain time is determined
by the hydraulically conductivity of the filter media. This
pre-set but will change over time. The filling and drainage
cycle will require monitoring and adjustment as the filter
clogs. Rejuvenating and resetting the top of the filter on
an annual basis will renew the conductivity. The plants
are also cut back at this time to ensure their vigour.
The clean water drains naturally under gravity to the
reuse tank. From here it is ready for reuse in the existing
irrigation system.
The water is delivered into the irrigation network by a set
of three high pressure bore pumps which are computer
16
control via the irrigation control system. A small jockey pump was included to provide reuse
water for the toilets in the visitor centre and the works depot. The water is passed over Ultra
Violet light tubes to kill off any bacteria that have not been filtered out to date.
The Fitzroy Gardens project is projected to save 69 million litres of mains water per year,
which equates to 59% of the irrigation water demand.
Pumped to
irrigation network
via UV disinfection
Reuse
Tank
Primary Tank
Drain to
reuse tank
Pumped to
Biofiltration
bed
Sedimentation
chamber
Diverted street and park
drainage via new drains
and weirs.
Primary screening
through a Gross
Pollutant Trap
17
Birrarung Marr
The design intent for the all three systems was
similar to that of Fitzroy Gardens. Birrurang Marr
diverged as the storage had to be separated from
the diversion point, which was next to the river. To
find a site large and clear enough to accommodate
the storage required that the harvested stormwater
to be pumped uphill. Therefore the storage and
treatment arrangement was the same as Fitzroy
gardens with the following components being
different:
The diversion structure was built within existing
larger twin culvert just upstream from the exit point
into the Yarra River. The Yarra River is brackish and
tidal at this point. A weir was installed into the
culverts to exclude the brackish water and to retain
stormwater within the culvert for pumping to the
storage. When the storage is full or the storm event
flow exceeds the capacity of the pumps, the
stormwater must be able to overflow the weir into the
river. To accommodate this yet minimise the
overtopping of the weir without lengthening the
culvert width, four Duck Bill rubber orifices where
installed. Made using memory retaining rubber, the
duck bills open with water pressure behind the weir
to allow water to exit. When the water pressure is not
sufficient, the duck bills close and prevent river water
entering the drain.
The GPT has been placed before the pump well at
the river’s edge to protect the pumps from larger
material in the stormwater. The diversion pumps are
high volume transfer pumps that will activate when
the primary tank is below capacity and switch off
automatically when the tank is full. The pumps will
also not run when salt is detected above 500ppm in
the stormwater. There is an automated valve that
allows the operator to dump the water behind the
weir for maintenance or if the water is too saline to
harvest.
18
Below is a schematic of the system outlining the diversion and treatment process, the
catchment area and the predicted volumes. The projected reuse equate to 83% irrigation
water demand of the irrigation area shown.
Alexandra and Queen Victoria Gardens
This project again uses the same principle of divert/capture, store, treat and store for reuse.
However, underground storages could not be install in the ground conditions present in both
gardens. The construction and cost risks created by the contamination levels and underlying
Coode Island Silt where too high. Therefore a process that utilised the existing ornamental
ponds in Queen Victoria Gardens and replacing an old depot building with an above ground
storage tank where adopted.
The diversion arrangement is similar to Birrarung Marr where a pump well is required to divert
the water from the drain to the ponds. However, the height different is only a matter of a one to
two metres, rather than the 30 metre plus height difference at Birrarung Marr. Also, in this
instance, the sedimentation chamber was placed before the pumps, after the GPT. This is due
to the known high volume of fine sands that are within this system and would therefore
damage the pump impellers.
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The other complexity in this system is that the existing storage ponds are positioned at
different elevations. Therefore the levels need to be controlled independently for each pond.
The first pond is shallow and will act only as additional sedimentation. The level in this pond is
set by a permanent weir. The second and third ponds will have both a storage and treatment
function. The second pond will have a large area planted out with native and ornamental water
plants that will provide both an aesthetic and nutrient stripping function. The level in the middle
pond will be controlled by an automated value and a pressure transducer. The drawdown will
be limited to a maximum of 300mm from the top water level, but can be reduced by the
operator through the remote controlled irrigation system. The top water level is maintained by
an overflow weir. The diversion pumps will also turn off when the ponds are full.
The lower pond is the largest and deepest. It will only have plants around the perimeter of the
ponds and will provide the most storage volume. The drawdown will again be controlled
remotely to a maximum point, nominally 300mm below the top water level. Again, an overflow
weir will control the full water level. However, a pump will be utilised to withdraw the water
from the lower pond and transfer the water to the biofiltration bed.
The biofiltration beds and reuse tank are located in Alexandra Gardens, which lies on the over
side of Alexandra Avenue, a primary traffic route between the eastern side of Melbourne and
the Southbank Port Melbourne area, linking the Monash freeway and the Westgate Freeway
above ground. The link was bored at night with careful traffic management and guidance, as it
also crossed major banks of power and communication cables. This was conducted before the
main tender was let to ensure that the project could be implemented as designed. Without this
crossing we were running out of options.
The biofiltration functions as per the other system. The difference here is that although the
beds drain under gravity, the water is collected under the bed in a pump well and then
transferred into the above ground reuse tank. Water is only processed when the reuse tank is
below a given level and there is water available in the lower ponds. Also, the contractor
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proposed using tube stock rather than the pre-grown plant slabs. It will be interesting to
compare any performance difference versus the apparent cost savings.
The reuse tank is an above ground poured in-situ concrete structure. The irrigation control and
UV disinfection is housed alongside the tank. The structure has replaced a former depot
building, alongside a stake park, which is on the larger footprint of the former depot site. This
provides us with the opportunity to provide information regarding this type of technology to a
section of the community that we do not access well, i.e. teenagers.
As is apparent when reading the above process description, although this project utilises more
“natural” elements, it is more complicated to control due to the number of pumps and level
controls that need to talk to each other to make it all work. This will take some time to get right.
We have been able to control the system through our existing irrigation control system, and
therefore it will be integrated to the irrigation operating contractor.
The Alexandra and Queen Victoria Gardens project is projected to save 20 million litres of
mains water per year, which equates to 55% of the irrigation water demand.
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Project finance
The overall project budget was $12 million dollars. This is approximately $2million more than
the cost estimate used for the funding submission. The increase costs can be primarily
attributed to soil investigation and management, design revisions and the inclusion of
additional infrastructure as the design moved from functional to detailed design.
The Australian Government provided $4.88Million towards the three projects.
A detailed cost summary is provided in the auditor’s report.
Volume of stormwater harvested and potable water savings
The project will be commissioned in the coming months. This will primarily involve refining the
level and pump control logic including challenge testing for likely problem scenarios. Actual
volumes saved have not been determined to date. These will be available post the first
irrigation session in April/May 2014.
The modelled potable water saving is 119million litres per year. This is slightly below the
objective of 124 million litres due to the redesign of the Alexandra and Queen Victoria Gardens
system.
Levelised cost of water supplied
Levelised cost for each project was determined to be;
Fitzroy Gardens $2.49 per kilolitre
Birrarung Marr $2.99 per kilolitre
Alexandra and Queen Victoria Gardens $3.17 per kilolitre
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Amount of GHG emission offset and/or energy saving achieved
The operational GHG emission will be offset through Council Carbon offset strategy. As the
systems are not yet fully operational, we are only able to provide the following estimates based
on pump sizes and run time estimate from the volumes we are estimating reusing and/or
treating.
Power estimation of the pump systems (kWh/yr)
System
Treatment
Irrigation
Fitzroy Gardens
7,187
8,816
Birrarung Marr
5,728
6,250
A&QVG
4,928
4,229
Total
16,003
11,978
9,157
Other environmental benefits
Each project treats stormwater to stormwater to best practise standards thus decrease the
stormwater pollution flowing to the receiving water, in this case the Yarra River. The quantities
reduced for each project are presented below.
Stormwater pollutant load reduction
Storage
size
(kL)
Catchment
area
(ha)
Stormwater flow
reduction (ML)
Fitzroy Gardens
5000
67
69
12100
18
155
4960
Birrarung Marr
2500
37
35
5870
10
82
2140
A&QVG
1330
34
20
5520
8.5
40
1400
Project
TSS (kg) TP (kg) TN (kg)
Gross
Pollutant (kg)
Environmental flows and flooding were not impacted positively or negatively through these
projects.
Social benefits
As discussed above, the parks and gardens of the City of Melbourne are highly valued by the
community, who are passionate about them and visit regularly as individuals or groups.
Fitzroy, Alexandra and Queen Victoria Gardens as well as Birrarung Marr are an important
part of Melbourne’s tourism offering and event spaces.
These three high profile parkland areas, all located in the eastern portion of Melbourne, make
a significant contribution to the character and liveability of Melbourne as well as representing a
high cultural, economic, social and environmental value to the City.
The projects will ensure that these values are not lessened by water scarcity. The project will
help ensure that the vegetation health is optimised and therefore contributes to the social
benefits of being able to have free access welcoming, shaded, cool and relaxing spaces,
especially in summer.
Due to their high exposure each project is able play a role in enhancing the general public’s
awareness of the potential to undertake sustainable initiatives involving infrastructure and
water supply even in sensitive heritage listed parkland. The profile and annual visitation rates
23
of the parks involved will enable these positive environmental messages to be spread widely
throughout the community. Each project site will include information signs that explain the
system components and intent. The City of Melbourne is also developing case studies and
web-based material that will be accessible by the general public and the industry practitioners,
giving more detailed information. Site tours have and will continue to be conducted for local,
national and international visitors interested in these exemplar projects.
The projects have also employed a larger number of local people over the different phases of
the project. The following contractors have contributed to the scheme;
 Berkrey Smith Consulting – Project Management

Cardno Gorgan Richards – Civil & structural design and documentation, construction
design supervision

NSP Geotechnics – Geotechnical analysis at Fitzroy Gardens, Alexandra Gardens,
Queen Victoria Gardens and Birrarung Marr

TenBuuren Irrigation Design – Pumps and irrigation design and construction
supervision

Noel Arnold & Associates – Soil Contamination assessment and management
documentation

GHD – Contaminated soil repository design and EPA submission

Lovell Chen – Heritage advice and Heritage Victoria submission for Fitzroy Gardens

Slattery Australia – Cost estimation

Hazcon – Dangerous goods advice

Waterman AHW – Services study & documentation

Surfcoast Survey & Drafting Services – site feature surveys

Ultra Electrical Services – Temporary power supply

Red Bar Excavations – Site demolition Fitzroy Gardens

Citipower –Power dis- & re-connection

AGL Electricity – Gas meter disconnection Fitzroy Gardens

MR Anderson & associates – Heritage inspection and report

Earth Graphic Design – Design of Fitzroy Gardens Information sign

Taylor Thomson Whiting Engineering Services – Depot design

Iouri Vaisman Consulting – Review of hydraulic design Fitzroy Gardens

Tree Logic – review of drainage installation method regarding impact on trees

Form A Sign – printing & installation of Fitzroy Gardens Information sign

Cardno Lane Piper – Geotechnical analysis at Birrarung Marr

Jetstream Drain Cleaning – CCTV inspection at Birrarung Marr

2 Construct – principal contractor on the Fitzroy Gardens construction project

Creative Brew – design of Information signs for Birrarung Marr and Queen Victoria &
Alexandra Gardens projects

MultiPro Civil Contractors – principal contractor on Birrarung Marr

GHD - Geotech/soil analysis at Alex gardens and Birrarung Marr

GHD & Golders - Geotech advise at Birrarung Marr

Jones & Whitehead – Landscape Architectural advice

Urban Initiatives – Landscape design on Birrarung Marr

Lambert & Rehbein – Structural design for QV&A-G
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
WEBB Australia – Electrical advise and design

Aquatic Systems Management – Water quality advice and design for QV&A-G

Cardno – Surveying services at QV&A-G

Cardno AUS – Underground services proofing

Evergreen Civil – Head contractor at Queen Victoria and Alexandra Gardens

Artesian Industries – Irrigation and Pump installation

Centratech Systems Pty. Ltd. - Irrigation and Pump controls
Summary of outcome realisation and its extent
The project has resulted in the following outcome in comparison to the previously outlines
goals and objectives;
Modelled to replace 119ML/yr as compared to the goal of 124 ML/year of potable water
by using treated stormwater to irrigate Fitzroy Gardens, Birrarung Marr and Alexandra
Gardens over a five-year rolling period. This will replace 62% of the potable water
demand for the three sites and equate to 15% of council overall annual irrigation need;
-
The projects have gone over budgets by 20% and have pushed the timeframes by 2
months. This can be attributed primarily to soil contamination and the resultant
additional investigation, design and construction tasks. We have maintained the high
quality of materials, finishes and water quality;
-
The projects have had no health and safety risks and have complied to environmental
laws throughout;
-
The landscape health will be ensured when we begin to provide a reliable, fit-forpurpose alternative water source for these significant heritage gardens that is
independent of future water restrictions;
-
Significant nitrogen, sediment, phosphorous and heavy metals reduction have been
achieved as shown above. This has significantly assisted the City of Melbourne
achieve its stormwater quality improvement targets;
-
Once the landscapes surrounding the project have been reinstated, which is ongoing at
present, the existing landscape values will be enhanced in all three locations, providing
an improved visitor experience. At Fitzroy Gardens a new Visitor Centre and an
additional 4500 square metres of garden area will be created as a result of minimising
the works depot footprint; and
-
Several education and awareness opportunities have been created to increase the
public’s connection with and understanding of stormwater management and water
conservation for large landscapes.
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EXPERIENCE SHARING AND LESSONS LEARNT
The following key learnings have been noted for future projects.

Placing tanks under buildings exposes the land and/or building manager to the risk of
blame shifting between the different construction contracts if there is future movement
or settlement;

The processing ability of the Bio filtration beds was under overestimated in the concept
design and hence increased (doubled) in the detailed design;

Soil conditions and contamination needs significant attention. It needs detailed
investigation early in the design process as it will have a big impact on constructability
and cost;

Cost effective management of contaminated soil is possible, but it just takes time and
persistence to achieve, especially with the changing regulations in this area;

Contractors will put forward alternatives to the tendered design. These may or may not
be to the benefit to the project, particularly from a performance and operational
perspective. Access to expertise is required to confidently access these alternatives;

An independent assessment of the proposed design can be valuable in cross checking
the details;

Having a multi-disciplinary team is value. Gathering this team regularly to cover all
aspects of the project will often provide different insights into issues and therefore
valuable solutions can be uncovered;

Consistent project management and oversight is invaluable to ensuring the delivery of
the original objectives;

Delivering a project in major event spaces provides significant extra consultation
through the design process. However, during construction the issues are not as
significant with contractors who are aware and cooperative;

Engineers love Pits. Pits have frequently multiplied as the project develops. An good
Landscape Architect can help hid them or question the need for pits;

Safe access for cleaning or inspection of underground structures can be a hidden cost
until you get to detailed design phase;

Every change in water level that is not free to move under gravity requires active
management and control of flows and/or pumps. This adds complexity to the operation
as well as increased energy and replacement costs; and

External funding was helpful to fast track the implementation of these projects. It, along
with the multidisciplinary team required to deliver these projects has enhanced the
knowledge and support for Integrated Water Cycle Management within Council.
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PROJECT FUTURE
Proposal for project handover, operation, maintenance and ongoing monitoring
The three systems, being whole located in parks or gardens, will be operated under our Open
Space contract. The contract is out to tender at present with the operations of these systems
included in the tender specifications. The contractor will be required to have expertise in
managing these systems as part of their contract. This will also get special attention in-house
with the appointment of a Water Management Officer in the Parks Services branch.
An operations manual covering the processes in details as well as the general risks,
performance levels and incident response requirements is also being developed. This will be
based on a manual developed for the Royal Park Wetland Stormwater Harvesting system
which involved with the contractors, external stakeholders and industry expertise.
Monitoring for of the water quality parameters such as pH, salinity and turbidity will be online
with alarms for operational boundaries set. Grab samples for E. coli, nutrient, heavy metals
and herbicide will be taken regularly through the irrigation season.
The inputs to the irrigation control system such as tank levels, pump faults etc. will also alert
the operator to the status of the live systems.
Remaining tasks or any outstanding work going past the funding agreement
The construction is complete and as mentioned above, the commissioning has started. This
will be ongoing for the next month or two and will likely require ongoing adjustment through the
first irrigation session as unforeseen issues with the programing arise. Council has also taken
the opportunity to enhance the surrounding landscapes at all three projects sites, these will
also be complete over the coming months and will add value to the spaces and the harvesting
systems.
We will explore the opportunity to increase the demand on the systems outside of the irrigation
season. This will include the option of using the soil as a storage reservoir. This will likely
involve interjecting the water under the topsoil layer in winter to recharge the subsoil, giving
trees in particular greater access to water reserves deeper down during summer. We will also
explore integration opportunities with buildings, as the water industry in Melbourne
increasingly moves towards sourcing water locally rather than from the catchments in the hills.
And as mentioned, we will further develop our knowledge collateral and provide easier access
for the general community and the industry practitioners to learn from our experience.
Another important aspect of the overall approach taken is the innovative use of passive
irrigation to store excess treated stormwater during winter months. The effect of soil storage
will greatly enhance the ability of the each park to withstand climate change by promoting
deeper root development and soil moisture storage – drawing on aquifer storage and recharge
principles.
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CONCLUSIONS AND RECOMMENDATIONS
The projects have been a huge success to date. Even before they have cleaned or saved a
drop of water they have had an enormous amount of interest from individuals and industry
professionals locally and abroad, who all applauded us for the foresight in implementing such
projects. Praise we share gladly with our Commonwealth Government partners. The projects
have also cemented the practise of Integrated Water Cycle Management within council, where
we are busily seeking the next opportunities. The project will provide a lasting legacy in
stormwater treatment and water security for highly valued open spaces. They will also provide
key focal points for education and raising awareness of sustainable water management.
We thank the Commonwealth Government and the many other contributors for helping the
City of Melbourne successfully deliver these exemplar projects.
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