WORKING WETLANDS PROJECT
FINAL REPORT
31 July 2013
ROYAL BOTANIC GARDENS
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
REPORT CLEARANCE/SIGN OFF
Function
Position
Name
Signature
Date
Prepared by
Senior Project Manager
Grant Cameron
Signed
29 August 2013
Approved by
Director, Corporate Resources
Jenny Steinicke
Signed
29 August 2013
Approved by
Director and Chief Executive
Prof Tim Entwisle
Signed
29 August 2013
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Table of Contents
Executive Summary
iii
Project Overview
Project Results and Outcome Realisation
Major Project Issues
iii
iii
iii
1. Project Overview
1.1
1.2
1.3
1.4
1.5
5
Background
Objectives and Goals
Project Conditions
Project Dates
Scope and Deliverables
5
6
6
6
8
1.5.1
1.5.2
8
8
Part A: Stormwater Diversion
Part B: Use of Lake Water for Irrigation
1.6 Funding Sources
8
2. Process and Methods
10
2.1 Project Governance
2.1.1
2.1.2
2.2
2.3
2.4
2.5
10
Project Control Group
Wetlands Implementation Group
10
11
Project Activities
Carbon Offset Strategy
Stakeholders
Risk
12
12
12
13
3. Project Assessment
14
4. Experience Sharing and Lessons Learnt
16
5. Project Future
17
6. Conclusions and Recommendations
18
Table 1
Table 2
Table 3
Summary of Project Milestone Dates
Funding Sources and Components
Working Wetlands Funding Scheme
Figure 1
Figure 2
Figure 3
Working Wetlands Part A General Arrangement
Working Wetlands Part B General Arrangement
Project Governance Structure
Appendix 1
Appendix 2
Project Photographs
Audited Financial Statements
Page ii
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Executive Summary
Project Overview
The Working Wetlands Project has two parts: Working Wetlands Part A and Part B.
Part A involves the diversion of stormwater into the Royal Botanic Gardens (RBG) Melbourne’s lake
system from streets adjacent to RBG Melbourne, construction of gross pollutant traps to intercept
debris, wetlands to treat the stormwater and reduce nutrient loads in the lake water, and a water
circulation network to shift water through the wetlands treatment train to further reduce nutrient levels
in the lake water.
Engineering modelling has predicted that up to 60ML per annum of stormwater will be diverted into
the lakes.
Part B involves the extraction of lake water, filtering and UV treatment, storage and pumping into the
existing irrigation system. Part B also involves installation of water treatment tanks and a treatment
building, underground boring and connection to the irrigation system.
Analysis suggests that up to 40% of the potable water currently used for irrigation can be substituted
with lake water annually.
Project Results and Outcome Realisation
Part A was completed on time and within the allocated budget. It is now in its operating phase. The
stormwater capture system is operating successfully. Stormwater from Domain Road and Anderson
Street is now diverted through two gross pollutant traps prior to delivery into RBG Melbourne’s lake
system. The treatment wetlands have been established and will continue to mature and increase in
efficiency during each growing season. The Floating Treatment Wetlands are fully established and
now only require ongoing maintenance.
Part B involves the extraction of lake water, filtering and UV treatment, storage and pumping into the
existing irrigation system.
A contractor was appointed in September 2011 to undertake the Part B ‘design and construct’ works.
The on-site works commenced in December 2011 and involved installation of water treatment tanks
and a treatment building, underground boring and connection to the irrigation system. Part B is now
in its operating phase.
Part B was delivered well within the allocated budget, with remaining funding being approved for
installation of a photovoltaic ‘solar electricity’ system.
The Official Opening of the Project was held on 23 August 2012.
The photovoltaic ‘solar electricity’ system will provide a sustainable source of approximately 60% of
the power needs of Working Wetlands (Parts A and B). The balance of the electricity required will be
purchased as ‘green electricity’. The installation of the panels and associated inverters and hardware
has achieved practical completion and the system will be commissioned in July 2013.
Major Project Issues
Major project issues were anticipated and management strategies established in accordance with the
RBG’s Risk Management Framework. This process suggested that the high project risks were (for
Part A): approvals and permitting; and pipe jacking under the Domain Road tram network; and (for
Part B): selection of an appropriate design consultant; and integration with the existing computercontrolled irrigation system.
The management strategies applied to these high risk items resulted in the risks not adversely
impacting on the project’s outcomes.
However, there were a number of issues that arose and required close control during the construction
and establishment phase.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Part A encountered unexpected soft ground conditions in several locations – particularly Pump Well 1
– that resulted in construction delays and additional costs. This was managed by re-scheduling of the
project’s activities and use of the ‘float’ within the construction program. The additional costs were
offset by savings in other areas of the construction.
Part A was also affected by birds grazing veraciously on newly-established wetland plantings. This
affected both the traditional and floating wetlands. The RBG had recognised the potential risk, and
included a requirement for the planting contractor to install netting. Nonetheless, the intensity of the
grazing was – and continues to be – a challenge to the project.
Part B did not have any major project issues. However, the interaction between Parts A and B
required careful management to ensure that a specific water level range was maintained in the lake
system that (a) allowed the treatment wetlands to establish and (b) provided for sufficient available
water to operate the Part B treatment system. As the treatment wetlands become further established
over the next year or two, this issue will decrease in significance.
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Royal Botanic Gardens
1.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Project Overview
1.1 Background
The Royal Botanic Gardens (RBG) Melbourne has been a treasured part of Melbourne’s cultural life
for more than 165 years – much loved by generations of Victorians, as well as by the many visitors
from interstate and overseas. It is a picturesque haven for recreation and an important resource for
education, conservation, science and horticulture. RBG Melbourne extends over 38 hectares and
houses a collection of more than 10,000 species of plants from around the world, including amazing
and diverse plant collections such as camellias, rainforest flora, cacti and succulents, roses,
Californian species, herbs, perennials, cycads, plants from Southern China and, in the Rare and
Threatened Species Collection, plants from south-eastern Australia.
This Project is part of an holistic approach to improve water management at RBG Melbourne. It aims
to decrease the amount of potable water that is currently used to irrigate the Gardens’ living
landscapes.
This holistic approach is known as the Integrated Water Management project that is divided into:
Part I:
Guilfoyle’s Volcano (a previous project): refurbishment of the historic landscape feature
to allow the landscape to be re-opened to the public and to be a reservoir for landscape
irrigation water.
Part II: Working Wetlands (the current Project)
Part A: stormwater harvesting, treatment, recirculation and biological treatment.
Part B: incorporating use of treated lake water in the Gardens’ irrigation system.
Part III: Alternative Water Sources (future project – unfunded): an additional part of the Integrated
Water Management project involving the identification and utilisation of alternative water
sources.
The RBG has an ongoing commitment to responsible use of irrigation water in the context of
maintaining a heritage-listed landscape. Prior to 1995, water consumption averaged 250ML per
annum. Following sustained efforts to reduce water consumption, the average water consumption
between 2000 and 2010 was 130ML per annum.
Current climate change projections of less precipitation and higher average temperatures are
expected to significantly increase the amount of water required to maintain the heritage landscape. In
the long term, and subject to annual fluctuations related to varying seasonal conditions, this increased
total irrigation water requirement has been estimated to average 180ML per annum (an increase of
38% on the 2000 to 2010 average use).
Irrigation is currently managed through a centrally-controlled irrigation management system with
18 satellite controllers, 500 stations, 7,000 sprinklers (excluding drip emitters), 4 flow sensors, 16 soil
moisture sensors and over 40 kilometres of pipework. Around 13.5 ha of lawn and 12.6 ha of garden
beds are currently irrigated (1.7 ha of the Garden is non-irrigated).
The lakes at RBG Melbourne are an integral part of the Gardens’ heritage-listed character. They
complement the living landscape and give a focus to visitor activities, while providing an important
habitat for local wildlife.
The Ornamental Lake system at RBG Melbourne was created at the turn of the 20th Century when
the Yarra River was deepened and straightened to control flooding. The edges of the lakes were
formalised in the 1920s when the bluestone walls were installed.
In the period to 1983, the amount of sediment in the Ornamental Lake increased to an extent that
excavation and removal of silt was required. Since that time, additional silt has been deposited such
that the lake now averages about 1.0m to 1.5m in depth.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
1.2 Objectives and Goals
The Funding Agreement (in Schedule 1, A.2.3) establishes the following objectives for the Project:
a. reduce nutrients entering the lake system and the Yarra River;
b. maintain lake water levels to improve landscape amenity, water quality and to establish a
healthy water storage through bio-remediation and circulation of harvested water within the
RBG Melbourne lake system; and
c. use harvested stormwater to irrigate RBG Melbourne’s landscapes and reduce the demand on
potable water by 55 million litres (ML) each year.
Objective ‘a’ was achieved, with an average phosphorous reduction of about 50% in 2012-13
compared to the previous decadal average.
Objective ‘b’ was achieved, with RBG Melbourne’s lakes now at optimum level and visitor amenity.
The increased health of the lake system and decreased public health risk was demonstrated in 201213 by the RBG’s key health indicator of cyanobacterial (blue-green algae) blooms being relatively
short-lived in intensity and mostly remaining within low to moderate population levels.
Objective ‘c’ was achieved. In the first 11 months of operation 19ML of stormwater was used for
irrigation of RBG Melbourne’s landscapes. The amount of lake water available for this purpose was
lessened by a particularly dry summer period, and the use of stormwater for testing and commissioning
of the system. Reduction in the demand on potable water is expected to reach 55ML in the system’s
first full year of operation (2013-14).
In addition, the RBG achieved the following project goals:
1. Deliver the project within known and agreed budget, time and quality parameters.
2. Manage project risk appropriately including Health and Safety risks and environmental
compliance.
3. Facilitate efficient training and handover of the completed Project to RBG staff.
4. Confirm ongoing running costs including staff time and any direct costs.
5. Through community engagement and education, increase the public’s connection with and
understanding of water conservation for large landscapes.
1.3 Project Conditions
RBG Melbourne is listed on the Victorian Heritage Register (H1459). The Register lists RBG
Melbourne as being a place of historical, architectural, scientific, aesthetic and social significance to
the State of Victoria.
In addition to this formal listing of significance, the Gardens are acknowledged as a loved and wellvisited part of inner Melbourne. During 2012-13, there were 1.83 million visitors to the Gardens.
The planning, design and implementation of the Project works needed to be suitably constrained such
that the heritage values of the site were respected, and disturbance to users and the ongoing
operations of the Gardens was minimised.
1.4 Project Dates
A project schedule was established as part of the project management component of the Project. The
dates contained in Table 1 overleaf provide a summary of the progress against the schedule of works.
In some cases individual activities were delayed, however the overall completion date for the Part B
works, 1 November 2012, was able to be maintained. The Official Opening of the project was held on
23 August 2012.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Table 1 – Summary of Project Milestone Dates
Milestone Description
Initial
Program
Date
Modified
Date
(Note 1)
Actual
Achievement
Date
1
Signing of the Agreement
28-April-2011
n/a
28-April-2011
2
Part A: Construction of stormwater
diversions and associated wetlands,
and planting of the two wetlands.
2-May-2011
n/a
2 May 2011
Part B: ‘Design and Construct’ contract
completed.
3
Part A: Construction of wetlands and
planting; construction commenced of
water circulation works.
Part B: Contractor appointed; detailed
design documentation completed;
construction commenced.
4
5
Part B: Site security established;
installation of conduits and irrigation
pipes commenced, and; horizontal
direct drilling and irrigation mains tie-in
completed; treatment tanks installed;
treatment building foundations
completed; evidence for completion of
works provided.
Part B: Installation of conduits, irrigation
pipes, delivery pump and water
treatment unit completed; construction
completed; practical completion
achieved.
Part A
16-Dec-11
1-Nov-2011
23-Jan-12
Part B
20-Dec-11
1-May-12
1-May-12
1-May-12
1-Nov-12
1-Nov-12
1-Nov-12
3-Jun-13
3-Jun-13
31-Jul-13
Part B: Complete system testing; defect
period commenced.
6
(Note 2)
Part B: Installation of photovoltaic cells
at the works yard, National Herbarium
and Observatory Gate buildings to
generate approximately 82,000
kWhs/annum of solar energy.
Note 1:
Where specific activities were delayed, these were agreed with the Department of Sustainability, Environment, Water, Population
and Communities and formalised in a Deed of Variation.
Note 2:
The photovoltaic system was included in the Project with the agreement of the Department of Sustainability, Environment,
Water, Population and Communities. No additional funds were required.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
1.5 Scope and Deliverables
1.5.1
Part A: Stormwater Diversion
The scope of Part A includes installation of diversion stormwater pipes and pits (Photographs 1 to 3)
in Domain Road and Anderson Street. These deliver stormwater to the RBG Melbourne lake system
via two gross pollutant traps (Photographs 4 and 5). A pump stations delivers water to Guilfoyle’s
Volcano (Photographs 6 to 8), from where it moves by gravity to the Nymphaea Lily Lake, Fern Gully,
Central Lake and Ornamental Lake respectively (Photographs 9 to 13). Additional circulation within
the lake system is provided by two additional pump wells.
Excess water overflows into the Yarra River through an upgraded outlet pit (Photograph 14).
The quality of the water is improved by filtering through a series of newly-constructed wetlands as
shown in the previous photographs and Floating Treatment Wetlands (Photographs 15 to 16).
The main components and operational arrangement of Part A are shown in Figure 1.
1.5.2
Part B: Use of Lake Water for Irrigation
Water is extracted from the Ornamental Lake via a pump well that delivers water to a treatment shed
within the Gardens. The lake water is treated by a ‘three barrier’ system comprising ultrafiltration,
ultraviolet exposure, and dosing with chlorine.
The treated water is then stored in a series of tanks (Photograph 17) before being applied to the
Gardens during the period the Gardens are not open to the public. The treated water is applied to the
Gardens over a specified period and at a pre-determined rate using the RBG’s existing computercontrolled irrigation system.
The main components and operational arrangement of Part B are shown in Figure 2.
Part B also included the installation of a photovoltaic system on the rooves of the RBG Melbourne
works yard, National Herbarium and Observatory Gate buildings to generate approximately 82,000
kWhs/annum of solar energy (Photographs 18 and 19).
1.6 Funding Sources
Funding for the Project was provided by the Federal Government through the Department of
Sustainability, Environment, Water, Population and Communities (‘DSEWPC Funds’); funds
generated by the Royal Botanic Gardens (‘Recipient Funds’); and other funding sources – principally
by the Victorian Stormwater and Urban Recycling Fund and the Victorian Department of Environment
and Primary Industries (formerly Department of Sustainability and Environment) (‘Other Funds’).
Table 2 provides a summary of the funding sources and the project components to which they were
applied.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Table 2 – Funding Sources and Components
Funding Source
Part A
Part B
Total
DSEWPC Funds
0
1,980,000
1,980,000
Recipient Funds
Myer Foundation
1,050,000
1,050,000
Melbourne Water (Note 1)
330,000
330,000
Friends of the Royal Botanic Gardens Melbourne Inc.
210,000
210,000
Royal Botanic Gardens Foundation
70,000
70,000
Other donors and interest
13,224
11,881
25,105
Other Funds
Stormwater and Urban Recycling Fund
Department of Environment and Primary Industries
1,000,000
1,000,000
740,000
740,000
South East Water
Total
Note 1:
3,413,224
350,000
350,000
2,341,811
5,755,105
Provided as in-kind support for the design and documentation of the Part A works.
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Royal Botanic Gardens
2.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Process and Methods
2.1 Project Governance
The RBG established Project Governance structure to provide assurance that the project would
achieve its objectives and comply with its obligations. The Project Governance structure is shown in
Figure 3.
2.1.1
Project Control Group
The Project Control Group (PCG) was a formally constituted committee of the RBG Board. The PCG
had the following members:

RBG Board Member

RBG Director and Chief Executive

RBG Director, Corporate Resources

RBG Director, Melbourne Gardens

DSEWPC Representative

South East Water Limited Representative

City of Melbourne Representative

Senior Project Manager

Project Manager.
The role and responsibilities of the PCG were to:

Provide oversight of compliance with the RBG’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 RBG Board on significant procurement items.
Over the course of the Project 20 PCG meetings were held. Prior to each PCG meeting a Project
Status Report was provided to all members. The Project Status Report provided a summary of the
works undertaken to date, including any issues that did have or had the potential to affect the works;
the budget status; an updated schedule; updated project Risk Assessment; details of stakeholder
matters; and an update on community engagement activities.
Minutes of the PCG meetings were distributed to all members and kept on the relevant RBG internal
file.
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Royal Botanic Gardens
2.1.2
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Wetlands Implementation Group
The Wetlands Implementation Group (WIG) comprised the core RBG staff project team members:

RBG Director and Chief Executive

RBG Director, Corporate Resources

RBG Director, Melbourne Gardens

Senior Project Manager

Project Manager.
The role and responsibilities of the WIG were to:

Monitor compliance with the Funding Agreement and any other funding agreements

Review and manage the detailed schedule and achievement of milestones

Review and manage the detailed budget and cash flow

Authorise Milestone reports and recommend sign-off by the Director, Corporate Resources

Authorise non-material changes to the activities, budget or schedule

Confirm implementation of the Health and Safety Co-ordination Plan

Review and manage project risks and the project risk assessment

Co-ordinate and authorise the allocation of internal RBG resources where required

Confirm compliance with RBG policies and protocols (including tender processes)

Identify ways to engage the community and the media with the project, and guide
development and implementation of the communications plan

Ensure designs were 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
RBG Melbourne landscape.
The WIG meetings occurred on a fortnightly basis for the majority of the construction period. The
meetings outcomes were recorded on an ‘Action Plan’ that provided a record of agreed actions and
decisions, but did not provide exhaustive minutes.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
2.2 Project Activities
The project activities were grouped into four phases of the project lifecycle, as follows.
Approvals and Permitting:
The scope of the works was determined and the need, or
otherwise, for permits and permissions to allow the work to
proceed was identified. The relevant approvals that were
investigated and, where appropriate, gained were cultural
heritage and native title, flora and fauna, Planning Permits,
Building Permits, Heritage Approval, and Work on Waterways
approval.
Design:
The principal activities were the selection and appointment of
design consultants in accordance with the RBG’s procurement
protocols, integration of the RBG’s operational needs into the
design process, and review of the draft documentation.
Tendering and Construction: Seeking tenders or quotations for the various work packages in
accordance with the RBG’s procurement protocols, attending to
works package ‘kick-off’ matters, stakeholder management,
construction review, defect identification, and payment review
and authorisation.
Close out:
Confirmation of defect rectification, handover and training of
RBG Melbourne staff, and completion of minor close-out tasks.
2.3 Carbon Offset Strategy
The Project (Parts A and B) is expected to generate an average power requirement of 143,000 kWh
per annum.
The carbon offset for the Project will be achieved to approximately 82,000 kWh per annum by the
installation of photovoltaic cells on the rooves of buildings in the RBG Melbourne works yard, the
National Herbarium of Victoria building and the Visitor Centre building.
Beyond the carbon offset capacity provided by the installation of the photovoltaic cells, the remaining
carbon offset for the Project of approximately 61,000 kWh per annum will be achieved by the
purchase of ‘green power’.
2.4 Stakeholders
RBG Melbourne is highly valued by the community, which is passionate about the Gardens and often
visits it regularly as individuals or in groups. RBG Melbourne is also an important part of Melbourne’s
tourism offering and is seen as one of Australia’s foremost Botanic Gardens.
The Project and the enhancement works at RBG Melbourne are a major milestone in the Gardens’
history. The Project and its associated activities have been of interest to many individuals and
groups.
Identification and communication with stakeholder groups has been an important part of the Project
works, and a key mechanism by which the community has and will learn about the Project and
leverage its already significant benefits.
To date, the Project has engaged stakeholders in a positive manner and facilitated beneficial
outcomes in many segments of the community. While any Project of this nature involves change and
development that can be challenging for some stakeholders, it has been noted that the changes
associated with this Project have been viewed in a universally positive manner by all stakeholders.
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
The Project has sought to identify and interact meaningfully with those stakeholders affected by the
Project and established a communications plan that met the needs of the Project and those of the
stakeholders.
A Community Engagement and Consultation Strategy was implemented that identified the internal
and external stakeholders and assessed their interest and information needs. The Strategy
suggested appropriate communication methods and channels, and assigned responsibility to team
members.
The Community Engagement and Consultation Strategy was reviewed regularly as the Project
proceeded.
2.5 Risk
A project Risk Management Plan was developed in relation to delivery of the Project, in accordance
with the RBG’s Risk Management Plan dated March 2011 and AS/NZS ISO 31000:2009 Risk
management-Principles and guidelines.
The following sources of risk were used in the risk assessment process:

Financial

Human Safety

Business Interruption

Environmental

Reputation and Image.
The risk assessment process 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 outlined as appropriate.
The project risk register was updated prior to each PCG meeting. The updated project risk register
was reviewed by the PCG at each of its meetings.
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Royal Botanic Gardens
3.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Project Assessment
The Working Wetlands Project has been delivered within the allocated budget and schedule. The
project construction deliverables have been completed and handed over to RBG Melbourne staff.
The system is now fully operational.
The project works were delivered by Victorian-based contractors and subcontractors. Some
materials, equipment and machinery were sourced internationally, however, anecdotal evidence
suggests the percentage of Australian-based materials and equipment was high. Labour for the
project was exclusively Australian.
As part of the construction works and ongoing operations of the Working Wetlands Project the
additional benefits of enhanced community and educational programs have been – and will continue
to be – delivered as social benefits to the local, Victorian and Australian communities. To date, 894
students and 49 teachers have participated in educational programs that use the Working Wetlands
as part of their learning experience. The Project has been presented to and discussed with a number
of industry groups including the ClearWater industry group, members of Botanic Gardens Australia
and New Zealand, and staff of the Adelaide Botanic Gardens. The Working Wetlands project is part
of the standard public program offering that is provided by the Royal Botanic Gardens’ Voluntary
Guides. Fixed interpretive signage is available for viewing by all visitors to the Gardens. During
2012-13, there were 1.83 million visitors to the Gardens.
An audit of the project has been carried out as required by the Funding Agreement. The Audited
Financial Statement to 30 June 2013 is included at Appendix 2.
The project funds have been fully expended other than amounts that have been retained for contract
retention payments, minor works, staff training and close-out tasks. These amounts are detailed in
the Audited Financial Statement at Appendix 2. Table 3 provides a summary of the expenditure and
funding of the Project to 30 June 2013.
Table 3 – Working Wetlands Funding Scheme
Financial Year
Recipient and Other
Contributions
DSEWPC
Contributions
Expenditure
2009-10(Note 1)
2,103,191
0
36,825
2010-11 (Note 2)
1,202,044
300,000
1,996,547
2011-12
268,551
1,500,000
2,356,248
2013-13
201,319
180,000
1,160,847
0
0
204,638
3,775,105
1,980,000
5,775,105
Remaining
Total
Note 1:
Note 2:
Includes all amounts up to 30 June 2010.
Includes $330,000 of in-kind support for the design and documentation of the Part A works.
Part A: The stormwater harvesting system has operated successfully since it was commissioned in
December 2011. The volume of stormwater diverted into the system is not measured. However,
observation of the RBG lake system since December 2011 has shown the lake system to be ‘full’ or
within its target operating range. The previously-observed ‘mud flats’ have not reappeared.
There was a significant improvement in water quality of the Ornamental Lake during 2012-13, with an
average phosphorous reduction of about 50% compared to the previous decadal average. While
some cyanobacterial (blue-green algae) blooms did eventuate over the warmer months, they were
relatively short-lived in intensity and mostly remained within low to moderate population levels.
Part B: The harvesting and use of treated stormwater to irrigate the Gardens first commenced in
August 2012. The system became fully operational in December 2012 after the initial round of water
quality tests indicated the system was operating within the treatment parameters. The Year 1 (August
2012 to end July 2013) treatment volume is 19ML. This is lower than anticipated due to the project
commissioning and intensive maintenance period, the need to lower the water level in the Ornamental
Lake in October 2012 to assist with establishment of the treatment wetlands, and an unusually dry
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Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
year with only 490mm of precipitation. The volume treated in the coming years is expected to
increase dramatically.
Due to the low volume of lake water used for irrigation in Year 1, the levelised cost of the Part B
scheme was relatively high at approximately $123,000 per megalitre (excluding GST). As the Part B
scheme achieves a full year of normal operation, the levelised cost is expected to decrease to
approximately $59,000 per megalitre under current-day average precipitation. In the longer term, as
the climate becomes drier and RBG Melbourne’s water demand increases, the levelised cost may
reduce further to approximately $39,000 per megalitre.
The increased power consumption of the Working Wetlands Project (Parts A and B) during 2012-13 is
estimated at 75,000kWh. This amount will be offset in the 2013-14 Financial Year by use of solar
power (refer below) and the purchase of ‘green power’.
The photovoltaic system was completed in July 2013. The system will now contribute to the Project’s
Carbon Offset Strategy during the 2013-14 Financial Year.
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Royal Botanic Gardens
4.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Experience Sharing and Lessons Learnt
The Working Wetland Project has provided a number of valuable lessons. These are both positive in
nature, where the expected outcomes have been exceeded, and negative, where outcomes have
been sub-optimal. The key project lessons are:

The implementation of the Working Wetlands Project and the changes to RBG Melbourne
have been universally viewed in a positive manner. The public understands and indeed
expects sustainable management of the RBG’s water bodies and irrigation water applied to
the Gardens. Prior to the works it was expected that there may be some detractors from the
project, however to date no adverse feedback has been received.

Visitors to the RBG are passionate and inquisitive about the Gardens and activities within the
Gardens. It is important to have a broad communications strategy. However, it is also
necessary to have activity-specific communications to explain transitory disturbances, noisy
activities or unusual activities. An example is the lengthy and visually intrusive installation of
Pump Well 1 near The Terrace (Tea Rooms). These activity-specific communications should
extend to visitors, tenants and local residents.

Careful consideration of ground conditions and geotechnical risk is important. Prior
geotechnical investigation of the ground and groundwater conditions at the exact location of
key infrastructure is important in mitigating project construction risk.

The use of Floating Treatment Wetlands is a valuable mechanism to provide additional
nutrient removal capacity within the lakes.

The control of excessively aggressive birds grazing on newly planted material is important,
particularly during the establishment phase of wetlands.

A functioning and effective project governance and control framework will assist with project
delivery and often allow additional benefits to be identified and implemented.
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Royal Botanic Gardens
5.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Project Future
The project has been handed over to RBG Melbourne staff. Training has occurred for the majority of
the project components and service agreements have been established for items such as routine
maintenance and inspection of the lake water treatment plant.
In the coming months, there will be additional training on specific elements of the Project, such as the
Automatic Weather Station that assists with the RBG’s application of the treated lake water. A
number of internal stormwater drainage pipes will be cleared by high-pressure washing and
inspected, to determine if additional incremental efficiencies can be gained from the RBG’s heritage
drainage system.
Performance metrics for the system will continue to be monitored, recorded and compared to the
established benchmarks, including offsetting one third of RBG Melbourne’s irrigation water in a 5-year
rolling period and the percentage of carbon offsets that can be gained from the photovoltaic system.
The benefits of the Working Wetlands Project will continue to be provided to the community through
public and educational programs.
Page 17
Royal Botanic Gardens
6.
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Conclusions and Recommendations
The Working Wetlands Project at the Royal Botanic Gardens Melbourne has been successfully
implemented.
Part A of the system now provides additional stormwater to RBG Melbourne’s lake system. This
additional water, combined with a circulation system and treatment wetlands, has successfully
improved the environmental and aesthetic quality of the lake system and decreased the nutrient load
being transferred to the Yarra River. The amount of stormwater diverted into the lake system is not
measured. However, an approximation of the amount captured in 2012-13 can be made, based upon
a pro-rata calculation of the 490mm of rainfall at RBG Melbourne for 2012-13 compared to
Melbourne’s long-term average rainfall of 550mm per annum. This approximation suggests that
53ML was diverted into RBG Melbourne’s lake system in 2012-13.
Part B of the system extracts water from RBG Melbourne’s lake system, treats the water to Class A
standard and uses it to irrigate RBG Melbourne’s lawns and garden beds. The Part B extraction and
treatment system directly offsets the need to use drinking water to irrigate the Gardens. In 2012-13,
19ML of treated stormwater was used to offset potable water use in irrigation. This is anticipated to
increase to 55ML/annum in 2013-14 as the system reaches its full operational capacity.
The Working Wetlands Project has a high level of public acceptance. Ongoing information and
education programs will continue to highlight the benefits of this Project.
Page 18
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1
Project Photographs
Page 19
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs
Photograph 1
Installation of diversion
stormwater pits in
Domain Road showing
how vehicles can use
the area normally
Photograph 2
Pipe jacking drill head
used to connect the
Domain Road
stormwater diversion
and the gross pollutant
trap
Page 20
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph 3
Pipe jacking
drilling bit used
to connect the
Domain Road
stormwater
diversion and
the gross
pollutant trap
Photograph 4
Installation of
gross pollutant
trap for the
Domain Road
stormwater
diversion
Page 21
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
5
The
completed
gross
pollutant trap
for the
Domain
Road
stormwater
diversion
Photograph
6
Installation of
Pump Well 1
that
circulates
lake water
from Picnic
Point to
Guilfoyle’s
Volcano.
Note sheet
piling needed
to manage
poor ground
conditions.
Page 22
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
7
Pump Well 1
after
backfilling
Photograph
8
The
completed
Pump Well 1
that
circulates
lake water
from Picnic
Point to
Guilfoyle’s
Volcano
Page 23
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
9
Nymphaea
Lily Lake
treatment
wetlands
under
construction
Photograph
10
Rock Riffles
in Fern Gully
Page 24
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
11
Ornamental
Lake
treatment
wetlands
during
construction
Photograph
12
Ornamental
Lake
treatment
wetlands
after
completion of
earthworks
and
placement of
protective
geotextile
Page 25
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
13
The
completed
Ornamental
Lake
treatment
wetlands
after planting
with
interpretive
construction
sign in
foreground
Photograph
14
Upgraded
outlet pit to
Yarra River
Page 26
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
15
Newly
planted
Floating
Treatment
Wetland in
Guilfoyle’s
Volcano
Photograph
16
Newly
planted
Floating
Treatment
Wetland in
Ornamental
Lake
Page 27
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
17
Treated
water
storage tanks
adjacent to
treatment
shed
Photograph
18
Photovoltaic
panels on a
roof in the
Works Yard
Page 28
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 1: Photographs (cont)
Photograph
19
Photovoltaic
panels on the
roof of the
National
Herbarium of
Victoria
Page 29
Royal Botanic Gardens
National Urban Water and Desalination Plan
Working Wetlands Project: Final Report
Appendix 2
Audited Financial Statements
This Appendix was intentionally removed
Page 30