The South Bank Rain Bank
(Storm Water Harvesting Project)
Final Report - May 2012
This report compiled by:
Graham Robinson,
South Bank Corporation
This report authorised by:
Matthew Lawson, A/General Manager, Planning & Design
South Bank Corporation
Contents
Contents
1.) Executive Summary
2.) Project Overview
3.) Process and Methodology
4.) Attachments
2
| RAIN BANK FINAL REPORT MAY 2012
2
3
5
13
33
1.
1.1
Executive Summary
Background
The 17.5 ha of public parklands at South Bank on the Brisbane River, is a critical
component of the success of the 42 ha South Bank precinct. These interactive
Parklands which incorporate sub-tropical landscaping and numerous swimming and
other water features are tremendously successful attracting large numbers of the
public all year round. Maintaining these Parklands requires significant quantities of
water which has been seriously limited since drought conditions in 2004.
As an interim measure South Bank Corporation utilised recycled pool back wash
water, supplemented by imported re-cycled water supplied to the Parklands by
tanker. These measures were still inadequate to maintain the Parklands to a “subtropical” standard in a high use environment and as a consequence significant loss of
low level and under storey planting occurred.
In 2007 planning began on providing a more sustainable and secure source of nonpotable water, resulting in a contract being awarded in February 2010 for a storm
water harvesting system, now known as Rain Bank.
1.2
The Project
Rain Bank intercepts storm water run-off from a 30ha West End/South Brisbane
catchment for use in the Parklands, South Bank. A key component of the system is
an interception pit constructed on an existing large-diameter storm water drain in
front of the Piazza. Water is pumped via this pit to an underground storage tank and
plant room developed under the site formally occupied by the Royal Brisbane
International College (RBIC) building. Initially, the water will be used for irrigation,
water features and toliet flushing, however there is an interest in considering its
future use as a source of water for swimming pool filter back washing and top-up
water for the pools and lagoons. In addition to harvested storm water, Rain Bank
also uses waste pool back wash water from the swimming pools and may also, on
occasion receive tankered imported water and to improve drought security.
Rain Bank includes:
(a) The Storm Water Harvesting Interception pit (SHIP) constructed on an existing
1950mm diameter storm water drain between the Piazza and the Riverside
Restaurants. The SHIP will incorporate a weir to exclude tidal river water and to
hold back the storm water run-off, a harvesting and pollutant trap.
(b) A 2 ML below-ground reinforced concrete storage tank has been constructed
under the site previously used for the RBIC building, the Rain Bank storage tank
will be sub divided into the Raw Water Storage (RWS) (1.75ML) and the treated
water storage (TWS) (0.25ML).
(c) A below ground plant room to house the treatment facilitates constructed as an
integral part of the storage tank.
(d) The Storm Water Treatment Plant (SWPT) to provide a high standard of filtration
and disinfection of the water for use.
(e) Treated water distribution pipelines and irrigation works.
3
| RAIN BANK FINAL REPORT MAY 2012
(f) Significant hard and soft landscaping as part of the redevelopment of the site.
Rain Bank is expected to supply approximately 77ML/year of treated stormwater for
non-potable uses within the Parklands, South Bank.
Additional project outcomes include:
1.3

Environmental benefits:
o Potential catchment management improvements as a result of having a
storm water harvesting system in place.
o Retention and treatment 77ML/year of storm water run-off removing
associated pollutants from the river.
o The potential to capture any accidental spills that occur in the catchment
in the pipeline upstream of the SHIP.

Social
o
o
o
Benefits:
Improved park amenity and quality of facilities.
Reduced potable water consumption.
Educational and demonstration benefits.
Project Summary
Total project Budget
Funding:
Dept. of Sustainability, Environment, Water,
Population, and Communities
Queensland State Government
Contract Award
Construction Complete
Commissioning Complete
1.4
$9,000,000.00
$3,300,000.00
$5,700,000.00
February 2010
March 2011
June 2011
Outcome
Apart from some additional scope items of work resulting from latent conditions (i.e.
increased river levels post flood) the project was successfully completed within the
budget and within the adjusted contractual time period.
As a result of the post contract additional works required, Rain Bank has only recently
become fully operational in automatic mode. Contractual validation is now finalized
but a full 12 month climatic cycle / operational period will be required to appropriately
assess the degree to which the project fulfills the initial objective. Current indications
however, provide considerable confidence that the design target of 77 mega litres p.a.
of treated water to the prerequisite quality standards will be achieved.
Completion of this 12 month cycle will also provide a better understanding of the
capacity of the Rain Bank installation to make treated water available for other uses
such as toilet flushing, water features, pool back wash etc. depending on the varying
demands for irrigation.
4
| RAIN BANK FINAL REPORT MAY 2012
2.
2.1
Project Overview
Background
South Bank Corporation (SBC) is responsible for the 42 ha South Bank precinct on the
banks of the Brisbane River. Since the Corporation’s inception in the 1990’s, the
Precinct has become a key part of the city’s urban fabric, combining business,
residential, dining entertainment and recreational facilities in the heart of the city and
providing a focus for many of the signature city celebrations, such as Riverfire and
New Year’s Eve. A major part of the precinct success is due to the 17.5 ha of public
Parklands within the South Bank Precinct.
Operation and maintenance of the sub-tropical Parklands requires a significant
amount of water, the availability of which has been seriously limited since 2004, with
the introduction of water restrictions in response to the major drought in South East
Queensland at that time.
Since 2004, SBC has implemented a broad range of initiatives to reduce water use
with a particular focus on reducing water used for irrigation and other non-potable
usages. In 2006 SBC was required to stop drawing water from the water supply
network for irrigation and has since relied solely on non-potable water sources for
irrigation, specifically the backwash water from the swimming pools and carted
recycled water, neither of which have been able to meet the full requirements of site.
In 2007, SBC began planning a stormwater harvesting project to reduce the
Parklands’ dependency on mains water supply, improve drought security and to
demonstrate urban stormwater harvesting.
2.2
Objectives
The overall objective of the project (now known as Rain Bank) was to develop a
substantial new source of water to substitute for potable and imported water so as
to improve drought security and the environmental sustainability of the significant
public asset of South Bank Parklands. From this various sub-objectives evolved:
Ecological
 Minimise initial and continuing consumption of resources and energy through the
application of energy efficient design principles;
 Ensure no adverse impact of the system on the Brisbane River;
 Ensure no unacceptable impact on the drainage system or flooding of the
stormwater catchment;
 Ensure that environmental noise levels from the system are within acceptable
levels.
Social
 Enhance the amenity of the Parklands through the availability of a more secure
and independent water supply;
 Produce water that is suitable and safe for its intended users;
 Ensure that occupational noise levels from the system are within acceptable OH&S
levels;
 Integrate the facilities into the Parklands to ensure no adverse aesthetic impacts;
 To promote Rain Bank and educate the public regarding storm water harvesting
generally.
5
| RAIN BANK FINAL REPORT MAY 2012
Economic




Ensure capital costs are with acceptable budget limits;
Ensure ongoing operational, ,maintenance and replacement costs are affordable;
Minimise the life cycle costs for the facility;
Encourage the local (Queensland economy).
Landscape
 Ensure that the required infrastructure is visually integrated within the Parklands
to minimize intrusive impact whilst remaining “accessible” for public information
and educational purposes.
 To develop a landscape solution that maximizes open public space and minimizes
obvious built form.
2.3
Conditions and Constraints
(a) Due to the Parklands’ ever increasing popularity, open public space is at a
premium. Any solution for the necessary infrastructure was therefore required to
minimize physical impact and if possible, even increase available open space.
(b) The construction and ongoing operation of the required infrastructure (including
the necessary storage and reticulation of treated water) within a busy, 24 hour,
public parkland was a significant constraint and influence on design parameters
and construction methodology and access.
(c) The proposed storm water inception point was located on an operational 1950 dia
storm water main only some 40 meters from the outflow point to the Brisbane
River. The imposed specific constructional constraints were further exacerbated
by the substantial tidal ingress into this existing storm water system.
(d) Another conditioning influence on the design of this proposed system was the fact
that the storm water runoff feeding the project was from a highly urbanized 30 ha
catchment within close proximity to the CBD of a major city.
2.4
Project Scope
Rain Bank intercepts stormwater runoff from a 30ha West End/ South Brisbane
Catchment for use in the Parklands, South Bank. A key component of the system is
an interception pit constructed on an existing large-diameter stormwater drain in front
of the Piazza. Water is pumped from this pit to an underground storage tank and
plant room developed under the site formally occupied by the Royal Brisbane
International College (RBIC) building. Initially, the water will be used for irrigation,
water features and toilet flushing, however there is interest in considering its future
use as a source of water for swimming pools and may also, if the need arises receive
tankered imported water from off-site. The objective of the Rain Bank project is to
provide a substantial new source of water to substitute for potable water and tankered
imported water and to improve drought security.
Rain Bank includes:
(a) The Stormwater Harvesting Inception Pit (SHIP) constructed on an existing
1950mm diameter stormwater drain between the Piazza and the Riverside
Restaurants. The SHIP incorporates a weir to exclude tidal river water and to hold
back the stormwater run off, a harvesting pump and gross pollutant trap.
6
| RAIN BANK FINAL REPORT MAY 2012
(b) A 2ML below ground reinforced concrete storage tank constructed under the site
previously used for the RBIC building; the rain bank storage tank will be
subdivided into the Raw Water Storage (RWS) (1.75ML) and the Treated Water
Storage (TWS) (0.25ML).
(c) A below ground plant room to house the treatment facilities constructed as an
integral part of the storage tank.
(d) The Stormwater Treatment Plant (SWTP) providing a high standard of filtration
and disinfection of the water for use.
(e) Treated water distribution pipelines and irrigation works.
(f) Significant hard and soft landscaping as part of the redevelopment and
reinstatement of the site.
Rain Bank is expected to supply approximately 77ML/year of treated stormwater for
non-potable uses within the Parkland which is anticipated will provide approximately
85% of irrigation requirements.
The following diagrams provide a summarized overview of the project scope and
location. They were produced as part of the design and tender documentation but
remain current.
7
| RAIN BANK FINAL REPORT MAY 2012
2.4.1 Rain Bank Flow Diagram
8
| RAIN BANK FINAL REPORT MAY 2012
2.4.2 Site Plan of Catchment
9
| RAIN BANK FINAL REPORT MAY 2012
2.4.3 Site Plan
2.5
Key Project Participants
Client
South Bank Corporation
Consultants
Project Management
Engineering/Civil Consulting
Engineering/Mechanical Electrical
Landscape
Irrigation
McLachlan Lister
Bligh Tanner
Webb Australia
Gamble McKinnon Green
Chris Edwards Irrigation
Contractors
Principal Contractor
Treatment Plant
Landscape
Stirloch Constructions
Stormaway
Penfolds
Advisors
Brisbane City Council
Queensland Health
Queensland Water Commission
10
| RAIN BANK FINAL REPORT MAY 2012
2.6
Project Status
A summary of the key project dates is provided below:
Key Project Milestone
Contract Awarded
Demolition of RBIC site
Rain Bank Construction
Landscaping
Rain Bank Storm Water Treatment Plant
Liana Lounge Installation
Testing and Commissioning
Rain Bank Practical Completion
Process Validation
Date
February 2010
March 2010
April 2010 to March 2011
July 2010 to April 2011
January 2011 to April 2011
March 2011 to May 2011
April 2011 to June 2011
June 2011
Ongoing
It should be noted that further delays to final commissioning under fully automatic
operation have only recently been resolved. These were the results of two issues:
(a) Post flood impact and excessive tidal influence.
Neither of these was a
“contractor issue” but has taken a significant amount of time and effort to
rectify.
(b) Although the initial immediate impact of the January 2011 flood event on the
actual site was significant its reinstatement was attended to, with delays
generally being contained to about 4-6 weeks. However, the consequential
delays caused by the extensive infiltration and contamination of the city’s
stormwater system by “toxic flood sludge” were to significantly impact on the
project’s transition from construction to operation. Brisbane City Council had an
enormous job to clear their drainage system and this of course included the
whole catchment area feeding the South Bank Storm Water Harvesting facility.
Final cleaning of the feeder mains and their “tributaries” was not able to be
completed until July 2011 and as a result attempts to switch the SHIP into
operational mode were simply delayed.
(c) Although the SHIP and SHARC plant and equipment had been generally tested
and commissioned as far as practical by the end of June 2011, final
commissioning and validation could not be achieved until the SHIP was
functioning normally and providing a regular supply of raw storm water to the
SHARC treatment plant.
(d) When the drain clearing had been finally completed and the SHIP became
“operational” further issues developed. As was intended in the design, the
various sensors in the SHIP collector detected excessive saline conditions of the
storm water and, correctly, prevented the pumping of storm water to the
SHARC. This led to an extensive review of the various potential causes of such
salinity and the cause was found to be a combination of higher than anticipated
high tide levels and the significant tidal surge created by the City Cat ferries. As
a result river water was spilling over the weir at high tide and was also
infiltrating the drain via the secondary storm water main (connected to the main
drain at the same R.L. as that for the top of the weir). After much discussion
with BCC and various manufacturers and engineers, it was resolved to install
specially designed “tidal flaps” on the river wall outlets of the main and
secondary drains to prevent backflow of river water whilst still maintaining
11
| RAIN BANK FINAL REPORT MAY 2012
storm water out flow when required. A separate supply and install contract was
arranged, once BCC formal approval was received and the initial installation was
finally completed in mid March 2012. Following this installation, a period of
minor adjustment to the design was required to ensure the flaps adequately
sealed the pipes from river water ingress (particularly during tidal surges
resulting from City Cat wakes).
(e) Final commissioning of the SHIP and SHARC was then commenced in late March
and is now virtually completed. The SHIP sensors have detected several
instances of “contamination” of the storm water from the catchment and these
are being investigated. However, the bypass system functioned as designed
and no “contaminated” storm water has been pumped to the SHARC holding
tank.
2.7
Funding Sources
Funding for this project was as follows:
12
$3,300,000
From Department of sustainability, Environment, Water, Population
and Communities.
$5,700,000
Queensland State Government through Queensland Water Commission
and through South Bank Corporation direct.
| RAIN BANK FINAL REPORT MAY 2012
3.
Process and Methodology
3.1
Process and governance controls and reporting
The project began its initiation as far back as 2007 when the Corporation began looking
at the option for providing a reasonably reliable alternative to potable water for
irrigation of the 17 ha of sub-tropical parklands and for use in water features and
eventually for flushing toilets. This process combined the inputs of both the Operations
and the Planning and Projects Divisions of the Corporation. Consultants were sourced
and appointed to carry out this initial study (Bligh Tanner) and numerous options were
investigated including sewer mining, de-salination (using river water) and finally
settling on a storm water harvesting option. During this early phase, the project was
managed by our Planning and Projects’ team with regular workshops held with our
Operation’s Division (they were in effect an in-house client) and consultants. These
meetings were minuted and a monthly report prepared for the Corporation’s Executive
Management Team in regard to progress and issues to be resolved.
As the project became “live” the process for monitoring became more formal. It
became a specific agenda item on a formal Senior Management Project Control Group
(PCG) which took the process right through to tender stage. An external Project
Manager was selected by an EOI bid process to independently manage the ongoing
project through the design and construction phase.
A separate “probity auditor” was also appointed to oversee the process of
documentation, tendering and tender review and award and was required to provide
advice to the team and also report to the Corporation Board regarding all probity
matters. The project process was given a ”clean bill of health” by the probity auditor.
During the design phase it was decided that the best option for the Corporation was to
package the tender documentation such that the “definable scope” works, (i.e.
demolition and site preparation, landscape and reticulation of water throughout the
Parklands) were fully documented and incorporated as part of a lump sum tender whilst
the structure and plant for both the SHIP and SHARC were incorporated as “design and
construct elements” within the lump sum with clearly defined performance
responsibilities for the contractor. This option worked successfully as it gave the
Corporation the opportunity to control the design of the measurable works while
allowing the contractor’s expertise to be incorporated for the bulk of the harvesting and
treatment infrastructure. There were several “hold points” for the contractor’s design
phase, giving the consultants and the Corporation, the opportunity to progressively
review and approve the developing design, relative to the performance criteria
established at the time of tender.
Throughout the design and construction process, regular in house team meetings were
arranged in conjunction with the consultants and invariably, the contractor, as well, to
ensure that required outcomes and operational expectations were achieved.
To track and facilitate progress during construction, regular fortnightly formal site
meetings were held between the Corporation, the full consultant team, and the
principle contractor.
These meetings were chaired and minuted by the project
management consultant.
In addition a monthly Project Control Group report was prepared by the Project
Manager and this report summarized all key issues relating to costs, quality, time,
13
| RAIN BANK FINAL REPORT MAY 2012
progress and risk and was presented to a monthly PCG meeting attended by the
Corporation’s CEO and Senior Executive Management Team.
In accordance with normal Corporation processes, a progress report on this project
(along with other major capital initiatives) was presented as a monthly report to the
Corporation Board meeting.
3.2
Carbon Emission Offset Strategy
The Corporation has been pursuing various options to plan and benchmark its ongoing
precinct wide energy efficiency initiatives (including carbon emissions reduction). Whilst
the specific energy consumption for the SHARC (Rain Bank) operations will be
monitored over a 12 month minimum cycle to achieve a realistic assessment, this data
will be incorporated into this precinct wide energy audit.
The Corporation has now settled on the option of using the EarthCheck international
certification program to drive its carbon emission offset strategy, in an integrated
manner, with its other ongoing environmental management issues. This program
requires South Bank Corporation to submit data on its environmental impacts, and
publishes outcomes of its energy consumption, green house gas emissions and other
environmental impacts. This data is compared against similar communities around the
world to benchmark our performance.
South Bank Corporation is currently preparing for certification under the EarthCheck
scheme. The certification requires the development of a Community Sustainability
Strategy that outlines our approach to achieve continuous improvement across the
environmental spectrum, including green house gas emissions and carbon offset. We
are required to establish environmental targets and objectives, and clear
implementation programs. We are also subject to yearly Certification to ensure
authenticity to our statements. South Bank Corporation has substantially completed
most of the requirements for certification, and recently undertook a Pre-Audit
Certification assessment.
The Corporation is anticipating its final Certification
assessment in July 2012.
3.3
Water Quality Management
The development phase of Rain Bank involved a number of key stages including
extensive water balance modeling to assess the expected system yield and viability of
the project and detailed stormwater modeling to identify potential impacts on local
catchment flooding.
Water quality and stormwater discharge monitoring was
undertaken to provide baseline data for system design. A hazard analysis and Critical
Control point study was also undertaken in consultation with Queensland Health and
other stakeholders to identify key water quality risks and define appropriate mitigation
measures and target water quality objectives.
Sensors within the SHIP chamber are designed to ensure a basic water quality standard
before this is pumped to the rain water storage facility for treatment. The general
parameters are for a range of PH between 6 and 8.5 and for conductively to be less
than 1600m/s. Anything outside of these parameters will activate the weir gates and
allow the release of this particular capture of stormwater back into the drainage
system.
14
| RAIN BANK FINAL REPORT MAY 2012
3.3.1 Treated Water Quality
The South Bank Rain Bank has been developed to provide an alternative source of
water to supply various demands within the South Bank Parklands including toilet
flushing. A summary of water sources and intended uses is provided below.
Water Source
Treated Stormwater
Intended Use
Initially:




Pool Waste Backwash Water


Irrigation of Parklands;
Refilling water features;
Public toilet flushing;
General external wash down and
cleaning;
Incidental event usage; and
Pool filter backwashing (provided final
filter flush is with potable water).
Possible future use:
Pool top-up.
Imported Class A+ Recycled
Water
All intended uses except swimming pool uses:





Irrigation of Parklands;
Refilling water features;
Public toilet flushing;
General external washdown and cleaning;
Incidental event usage.
Treated water quality objectives were specified based on the outcomes presented in
the Water Quality Discussion Paper for Stormwater Harvesting – South Bank
Parklands (Bligh Tanner, 2008) which was prepared during the design development
stages to:
(a) Determine likely untreated stormwater runoff quality;
(b) Determine likely constituents of concern encountered in urban stormwater
quality;
(c) Summarise water quality issues of the untreated pool backwash water;
(d) Summarise water quality issues of the imported water;
(e) Determine treatment objectives to protect the environment and human
health; and
(f) Outline proposed treatment processes to achieve required treatment
objectives.
The Water Quality Discussion Paper reviewed available information on raw stormwater
quality and treated stormwater objectives relevant to each of the proposed uses.
From this process a set of water quality objectives were defined for the Rain Bank
SWTP which were principally based on the Australian Guidelines for Water Recycling:
15
| RAIN BANK FINAL REPORT MAY 2012
Stormwater Harvesting and Reuse – Draft for Public Comment (Phase 2) (EPHC,
NHMRC, & NRMMC 2008b) as this provided the most relevant reference guideline for
non-potable uses. Further water quality objectives were also specified for a range of
additional compounds not covered in the aforementioned guidelines based on
Queensland Water Recycling Guidelines (EPA 2005), Australian and New Zealand
Guidelines for Fresh and Marine Water (ANZECC & ARMCANZ 2000) and the Australian
Guidelines for Water Recycling (Phase 1) (NRMMC, EPHC & AHMC 2006).
A detailed risk assessment was also undertaken to identify key risks and to define the
control systems required to manage risks and the key points in the system at which
the risks should be managed. To achieve this a Hazard Analysis and Critical Control
Point (HACCP) process was used, consistent with the management frameworks
recommended for the development of water supply systems in Australia, including in
the Australian Drinking Water Guidelines (2004).
In summary the Rain Bank Storm Water Treatment Plant was designed to produce
water fit for purpose using a multiple barrier treatment approach and includes the
following elements:
(a) Pre filtration where gross pollutants are removed to prevent following elements of
the process stream becoming overloaded.
(b) Coagulant dosing and mixing. The coagulant mixes with the stormwater to cause
fine particles to join together in larger groups, making it easier to separate solids
from the water during the clarification process.
(c) Lamella Plate Clarifier where solids are removed from the stormwater using a
gravity settling process.
(d) Primary sand filtration where smaller particle are removed from the stormwater
and turbidity is reduced prior to disinfection.
(e) Activated carbon filtration to remove any volatile organic compounds that may be
present in the stormwater.
(f) UV disinfection to provide the primary disinfection of bacteria, viruses and
protozoa that may have passed through the upstream treatment system.
(g) Residual dosing to provide secondary disinfection and maintain a free chorine
residual in the treated water storage and distribution system.
16
| RAIN BANK FINAL REPORT MAY 2012
A summary of the key water quality objectives is provided below.
Parameter
Units
Minimum Log
Reduction Required
E.Coli
CFU/100mL
3.1
Performance Required
Median
95%ile
<1
<10
Viruses
Rotavirus/Adenovirus
3.5
F-RNA Bacteriophage
PFU/100mL
<1
<10
Somatic Coliphage
PFU/100mL
<1
<10
CFU/100mL
<1
<10
Suspended Solids
mg/L
<5
Turbidity
NTU
Protozoa
Cryptosporidium
Clostridium Perfringens
3.4
pH
<2 (max
<5)
6 – 8.5
Chlorine
>0.5
Since these objectives were set, the guidelines have to some extent changed, in
particular, the Australian Guidelines for Water Recycling: Stormwater Harvesting and
Reuse (July 2009). The Log reduction targets for treated stormwater specified in
these guidelines are provided below.
17
| RAIN BANK FINAL REPORT MAY 2012
Use
Log Reduction Targets
Municipal use, with
unrestricted access – open
spaces, sports grounds,
golf courses, and nonpotable construction uses
(e.g. dust suppression)
Dual reticulation with
indoor and outdoor use OR
Irrigation of commercial
food crops
Viruses (represented by
Adenovirus)
1.3
Protozoa (represented by
Cryptosporidium spp.
Oocysts)
0.8
Bacteria (represented by
E. coli)
1.3
Viruses (represented by
Adenovirus)
2.4
Protozoa (represented by
Cryptosporidium spp.
Oocysts)
0.8
Bacteria (represented by
E. coli)
2.4
Water Quality Criteria
Turbidity: <25 NTU
(maximum), <10 NTU
(95th percentile), <2 NTU
(target)
E.coli <10 CFU/100mL
(median)
Turbidity: <25 NTU
(maximum), <10 NTU
(95th percentile), <2 NTU
(target)
E.coli <1 CFU/100mL
(median)
While the SHARC SWTP water quality specification does not explicitly meet the treated
water quality criteria for dual reticulation (specifically E. coli <1 CFU/100mL median)
it does exceed the minimum log reduction targets for all parameters. It is also noted
that the UV disinfection dose rate specified for the SHARC, based on the Australian
Guidelines for Water Recycling: Stormwater Harvesting and Reuse – Draft for Public
Comment (Phase 2), is considered by current water industry standards to be
significantly higher than required.
As the plant has only recently been operated fully with stormwater, the actual
performance of the system and quality of the treated stormwater has not been
validated. This process is underway but a 12 month operational period is really
required. Ultimately the suitability of treated stormwater for specific uses will be
dictated by the quality of the treated stormwater. However, based on the initial
results, we are confident that the treated stormwater will be suitable for irrigation,
water features and toilet flushing as originally intended.
CSIRO has also expressed an interest in this project and have installed automatic
samples within the treated water distribution system to regularly test the water quality.
This information will be provided to the Corporation on a regular basis.
3.4
Stakeholders
Several key stakeholders were consulted/involved with the project at the various
stages. These included Queensland Health in regard to water quality control and
management; Queensland Water Commission in regard to general principles and
policies to be applied; and BCC in regard to the storm water catchment system and the
detailed design of the SHIP and weir. As owner of the stormwater main over which the
SHIP is constructed, BCC required that they enter into a license agreement with the
Corporation to formalize approval to “break into” the storm water main and to construct
the weir and other infrastructure associated with the SHIP chamber. This agreement
protects the interests of both BCC and the Corporation.
18
| RAIN BANK FINAL REPORT MAY 2012
3.5
Community Engagement
A key requirement right from the early design stage of the project was to provide a
public education component in order to utilize the popularity of the Parklands, within
which the project was situated, to encourage as much “visitor interaction” as possible
and to explain, not just the Rain Bank project, but the importance of water
conservation and the principles of storm water harvesting generally.
The Rain Bank interactive display provides a year-round interactive educational
opportunity for visitors to learn about the water cycle, stormwater harvesting and
conservation. The water treatment plant can be viewed through a special window along
with audio-visual displays that explain the urban stormwater story, the treatment
process, vital statistics and flow rates. This type of interpretive access in such an
accessible location is unique in water projects in Australia. The prime South Bank
location is easily accessible and will attract a great number of people to Rain Bank while
the educational facilities will contribute to a greater understanding of stormwater
harvesting and water sustainability in the wider community. Rain Bank also provides a
significant learning opportunity to the water industry and the broader community, and
will hopefully assist with the development of further such projects.
Industry interest is already quite significant, with frequent visits by engineering and
other interest groups. Tours of the facilities are by arrangement and these are also
proving popular.
3.6
Official Launch by her Majesty the Queen
On Monday October 24th 2011, her Majesty the Queen officially launched the Rain Bank
at South Bank. The official party comprised of:
- Her Majesty the Queen
- His Royal Highness, the Duke of Edinburgh
- Queensland Premier Anna Bligh
- Senator Don Farrell
- The Corporation Chairman Steve Wilson
In addition, invited guests representing State and Local Government and industry
professionals and members of the public were in attendance. As part of the Royal Tour
of Queensland, this event attracted significant media and public attention and provided
considerable publicity to the Rain Bank project and to the importance of water
conservation and to storm water harvesting generally.
3.7
Project Risks and Challenges
A project of this type and in this location was bound to have associated risks and
issues, particularly during construction. Some of the more significant of these and their
resolution, are as follows:
3.7.1
Ground Conditions
The potential exists for poor ground conditions at both the SHIP and SHARC sites. The
rock level for bearing for the SHARC (Storm Water Harvesting and Reuse Centre) was
thought to be 20-30m below the surface which could not be properly confirmed prior to
demolition of the RBIC building on the site. The contractor demolished the building as
19
| RAIN BANK FINAL REPORT MAY 2012
a high priority and undertook urgent geotech investigations to confirm the bearing
depth prior to finalizing the design for the foundation structure. This has been offered
by the contractor as driven timber piles at a considerable cost saving to the project.
This cost saving was achieved in the final outcome.
3.7.2 Dewatering
Due in part to the proximity of the sites to the river, the ground water was at a
relatively high level. Following preliminary site investigations this had been estimated
for both the SHARC and SHIP construction with appropriate provisional allowances
within the contract sum for removal and treatment of this anticipated ground water. A
“spear pump” rung system was installed to cope with the quantum of ground water
encountered with the real “risk’ element being the “quality” of the water and the
consequent methods required for disposal . As it turned out, the “quality” was within
limits required to allow disposal to BCC drains. The “quality” was monitored throughout
the de-watering phase with no issues identified.
The end result was that the
provisional allowances for de-watering were generally adequate to cover costs incurred.
3.7.3 Acid Sulphate Soils
The contractor specially excluded the risk of acid sulphate soils and only costs
associated with disposal of some. Considering the relatively large volume of excavation
required for SHARC and SHIP structures, this was a considerable risk to the project. A
“non contractual” allowance was built in the overall project budget to cover this risk but
“good fortune” was on our side and there was no acid sulphate soils detected during the
project. The budget allowance was then able to be re-allocated to assist with other
cost issues on the project.
3.7.4 Construction of the SHIP
Although the risks associated with constructing the SHIP infrastructure over a “live”
1950 diam stormwater drain whilst also dealing with tidal ingress, were largely a
“contractual risk” , there will still an overall project risk particularly regarding time
issues. The contractor, Stirloch, developed a methodology for constructing the SHIP
that was fundamentally construction of the “pit” in layers above ground in the form of a
large caisson. This was then lowered into position by excavating from within the
caisson until the first section was down to ground level. The second, third sections etc
were progressively formed and lowered until the final depth was achieved. The storm
water main was left intact as long as possible (slots in the caisson walls allowed the pit
to be lowered over the pipes). Much of the pit structure was then completed prior to
the section of pipe within the chamber being removed. A temporary moveable baffle
plate was installed on the downstream storm water pipe penetration to reduce the tidal
impact on available working hours. This baffle plate was only lowered whilst workmen
were in the pit and was raised outside work hours and during any rain event to ensure
the function of the storm water drain was maintained.
Overall, the methodology worked well and although the SHIP did take longer than
anticipated, to complete, the adopted methodology and the construction expertise of
the contractor combined to minimize the potential impact of this critical part of the
project.
20
| RAIN BANK FINAL REPORT MAY 2012
3.7.5 Proximity to existing service Corridor
The location of the SHARC and SHIP structures with very close proximity to a major
Parklands Services corridor (incorporating both HV/LU power plus Telstra mains) was
unavailable due to the generally limited space available for the project. Again, whilst
this is a known “contractor risk” it was also a potential project risk with the potential to
impact on numerous other stakeholders beyond South Bank, should have any damage
occurred to these essential service mains. Both the SHIP and SHARC structures
involved major excavation works as close as 1 metre, in places to the service corridor.
Very detailed locational works on the part of the contractor (including frequent “pitholing”) ensured that the final design of the structures, and the development of
appropriate construction methodologies, fully acknowledged this significant risk. As a
result no issue relating to existing services, were encountered during construction.
3.7.6 Contaminated Excavation Material
Apart from the acid sulphate soils risk discussed above, there was a real risk of
contaminated soil being found on either/both of the excavation sites. Research into
“historical” data did not identify any potential hot spots, however, given previous
experience with the South Bank area generally (being the former Expo 88 site) the
potential for contaminated fill material to be found was quite real. A project budgeting
allowance was made, initially, but as regular testing of excavated material proved
negative to contamination, this budget allowance, as far as acid sulphate soils, was reallocated to other project issues.
3.7.7 Site Access/Congestion
The potential issues associated with carrying out significant construction works within a
24 hour, highly used, public Parkland were understood (from past project experience).
These issues were clearly identified to the project team, and importantly to the
contractors at tender time. The contractors were required to identify at tender time,
the proposal methodologies to deal with such matters as vehicular access, traffic
(including pedestrian) management, noise and dust control, appropriate site hoarding
and public safety generally.
The Corporation’s Operational Team including security, cleaners, maintenance crews, as
well as our own property management and public relations teams worked very closely
with the Contractor to proactively manage potential issues and minimise the impact on
Parkland patrons and other stakeholders.
This process was even more critical, given the other concurrent constructural activity in
the same area such as the ABC project and the QLD Conservatorium new stairs. A
combined traffic management plan to deal with all 3 projects and to concurrently
maintain access to stakeholders such as QPAC theatres and the QLD Conservatorium
greatly assisted in minimizing overall impact.
The Corporation, working with the proactively and with the full cooperation of the
Contractor (Stirloch Constructions) was able to minimise the impact on the public, our
tenants and stakeholders with the result that complaints were negligible and the
potential for “tenant compensation” due to the works, was averted.
21
| RAIN BANK FINAL REPORT MAY 2012
4.
Project Assessment
4.1
General Overview and Project Works
The scope of the works as originally proposed has been generally procured and
constructed in accordance with the brief of requirements and within budget. In
summary, the SHIP, the SHARC and the site reticulation of treated water including all
landscape reinstatement works have been completed and are now in operational mode.
The total project, now known as Rain Bank, will require at least a 12 month operational
cycle to allow appropriate data collection and analysis in order to assess the degree of
success in achieving the overall project objective.
The overall objective of the project (now known as Rain Bank) was to develop a
substantial new source of water to substitute for potable and imported water so as to
improve drought security and environmental sustainability of the significant public asset
of South Bank Parklands.
The objective will undoubtedly be achieved but it will be important to assess the
quantum of this success.
The treated water-use requirements for pool backwash, water feature top up, irrigation
and toilet flushing all have differing demands and influences, (particularly climatic) and
these demands will not necessarily be “in sinc” with available storm water run-off. This
will be particularly evident during winter months when, traditionally, rainfall is less
frequent, (hence less storm water run-off and higher irrigation demand) and the
availability of pool backwash water is reduced due to much less intense usage of the
pools.
These factors have been incorporated into the design forecasts that Rain Bank will
achieve approximately 85% of the Parklands irrigation requirements. However a full 12
months (minimum) climatic cycle will be necessary in order to “measure” the success in
achieving this overall objective.
The size of the SHARC storage tank was also the subject of considerable review and
debate during the initial design studies with capacity options varying from 1 megalitre
to 5 megalitre. An analysis of all options and benefits verse costs determined that for
the South Bank requirements, a 2 megalitre option delivered best value and that any
increase above the capacity provided only marginal gains in “drought proofing” whilst
adding substantially to the capital costs.
The treatment and reuse of the bulk of the pool backwash water has been a significant
factor in providing the majority of irrigation water supply to the Parklands for several
years. The quantum of water required is quite significant (approximately 140,000 litres
for every backwash and these vary from 1-3 times/day depending on pool usage).
Prior to Rain Bank, this was treated within the pool plant room and pumped to
temporary above ground storage tanks from where it was required to be distributed
around the Parklands by mini tankers. All backwash water is now piped direct to the
SHARC raw storage facility and then treated and pumped to the irrigation network.
This has provided a much more effective and efficient treatment and distribution
system and one that is directly linked to the irrigation for the Parklands (and
progressively to toilet flushing and water feature top up).
22
| RAIN BANK FINAL REPORT MAY 2012
A second important contribution from the pool/stream system is that of actual
rainwater catchment. The combined surface area of these water zones is significant
and during periods of rainfall provides a major source of water that, under previous
circumstances, would have been discharged as overflow into the storm water system.
With the advent of Rain Bank, this rain water “run-off” is now able to be collected in the
pool plant room and pumped direct to the SHARC raw water facility, to supplement the
stormwater harvesting catchment supply.
Since 2006 when South Bank ceased to utilize any potable water supply for irrigation,
reliance was on the pool backwash water with some supplementary supplies of recycled water bought in by tanker. Tanker supplied water was not only expensive
($19.50/kilolitre) it was also inefficient and very time consuming. In order to minimize
the quantum of such supply, the Corporation adopted a policy of prioritization for
irrigation with the first priority being the survival of “significant vegetation” (e.g. trees
etc). This resulted in much reduced “under storey” vegetation to the point that the
Parklands lost much of its “sub tropical” character.
Rain Bank has now meant that, whilst plant selection continues to favour those with
more “drought tolerant” characteristics, the original sub-tropical concept for the
Parklands is now able to be largely re-instated. This is particularly evident in the
rainforest area where a whole new “under storey” has been re-established and a new
“upper canopy” irrigation system has been installed providing a more natural rainforest
watering environment.
4.2
Achievement of sub objectives (refer to section 2.2, objectives).
4.2.1 Ecological
“Maximise initial and continuing consumption of resources and energy through the
application of energy efficient design principles”.
The design of the project from optimization of catchment, pumping and storage
capacity, through to plant and equipment selection has had efficiency and effectiveness
as significant guiding parameters from the outset.
Obviously, there was always going to be an energy requirement to capture and treat
raw storm water and to re-distribute the treated water. The aim was to ensure that
energy efficiency principles were driving the design. Apart from the obvious savings in
time, cost and energy achieved by NOT requiring the use of tanker delivery and
distribution as a result of Rain Bank, the Corporation has adopted a precinct wide
approach to energy use reduction and sustainability that will incorporate the Rain Bank
project as part of the “global picture” (Refer to section 3.2).
A full 12 month cycle of operation will be required to ascertain the actual energy usage
for Rain Bank.
“Ensure no adverse impact of the system on the Brisbane River”.
The retention and treatment of 77Ml per year of stormwater run -off through Rain Bank
will remove a significant amount of pollutants from the river and will improve the
overall health of the ecosystem. The installation of Rain Bank also means cleaner
waterways because any accidental spills that occur in the catchment can be captured in
the pipeline upstream of the SHIP.
23
| RAIN BANK FINAL REPORT MAY 2012
“Ensure no unacceptable impact on the drainage system or flooding of the storm water
catchment”.
Rain Bank has been constructed on an existing stormwater drainage system in a highly
developed mixed use urban catchment. During rain events storm water catchment
flows into a 1950mm dia. Stormwater pipe which runs below Glenelg Street. There is
also a 1800 dia. relief drain connected to the 1950mm dia. Stormwater pipe in Glenelg
Street near Merivale Street. Both pipes discharge to the Brisbane River under the
South Bank Riverside Restaurants Building.
These pipes are affected by tidal
inundation.
The Storm Water Harvesting Inception Pit (SHIP) has been constructed over the main
1950mm dia. Storm water pipe and a weir within the SHIP allows stormwater to be
intercepted and pumped to the main Rain Bank storage tank. The weir also works to
keep salty river water out of the system. The height of the weir was set to provide a
balance between excluding river water and minimizing the risk of upstream flooding,
taking into account a statistical analysis of the recorded tide height data from 1985 to
2007 from the Brisbane Port Office and the results of SWMM modeling to demonstrate
the effect of the structure on upstream hydraulics. The weir is electrically actuated
with a backup power supply and is designed to overtop during high flow in the unlikely
event that the weir actuator fails.
Since the construction of the SHIP, (and post 2011 flood event) it has been observed
that actual river levels have been approximately 200-400mm higher than historical
records previously had indicated. This resulted in much more frequent “overtopping” of
the weir and consequent regular contamination of the stormwater with river water. As
a result, “tidal flaps” were required to be installed on the river outlets to prevent
backflow whilst still maintaining storm water flow during any rain event (Refer to
commentary in 2.5 Project Status).
“Ensure that environmental noise levels from the system are within acceptable levels”
The SHIP is contained below ground with no perceptible operational noise at ground
level. The SHARC is similarly largely below ground, but does have a reasonably large
viewing window to the plant room for the public. Whilst the plant room generates
appreciable noise when in the full operation, these levels are within safety limits for the
staff working within the plant room and due to the window design and glass thickness
required for safety reasons, noise levels external to the plant room are barely
discernible.
4.2.2 Social
“Enhance the amenity of the Parklands through availability of a more secure and
independent water supply”.
“Produce water that is safe for its intended users”.
Rain Bank has been designed to deliver 77 megalitres of treated water per annum
which equates to 85% of requirements for irrigation. A full 12 months of operational
cycle will be required to ascertain the actual output verse design objective. However,
the enhanced efficiency of the distribution network (direct to the Parklands irrigation
system) and the availability of additional water supply is already showing results in a
return to the “sub-tropical” landscape.
24
| RAIN BANK FINAL REPORT MAY 2012
A significant amount of work was also completed throughout the design process to
ensure public safety, this included:




A Hazard Analysis and Critical Control Point (HACCP) study in consultation with
Queensland Health to identify key water quality risks and define mitigation
measures. This process was also used to specify target water quality objectives
for Rain Bank.
Detailed stormwater modeling to identify potential impacts on local catchment
flooding.
Consideration of all design aspects with respect to public access and safety.
Developing a rigorous process validation and water quality testing program to
ensure that the water produced by Rain Bank meets the target water quality
objectives specified.
“Ensure that occupational noise levels from the system are within O.H.& S levels” (refer
to 4.2.1 above re noise levels).
“Integrate the facilities into the Parklands to ensure no adverse aesthetic impacts”.
The “sub-ground level” design adopted for both SHIP and SHARC and the creation of
much needed useable open space above these structures has ensured a positive impact
has been provided. The design and location of the plant room with its public viewing
window being accessible from the rainforest stream area and provides an ideal balance
between having public access, yet being a semi discreet location. The location within
the rain forest area also assists in promoting the Rain Bank/storm water harvesting
story.
“To promote Rain Bank and educate the public in regard to storm water harvesting
generally”.
The “Rain Bank” installation facilitated by the public viewing area and the interactive
display, has attracted significant publicity and resulted in interest from both the public
and industry groups. Numerous “tour groups” have been conducted with very positive
feedback. The project has also been awarded the “eWater – Water Sensitive Urban
Design Award” by the Healthy Waterways Partnership of SEQ.
4.2.3 Economic
“Ensure capital costs are within acceptable budget limits”
The total project cost budget of $9m including consultation fees, construction costs and
other associated costs was achieved. However additional costs, post contract, to
provide the tidal flaps and to deal with post flood issues amounting to approximately
$360k, were required to be separately funded by the Corporation.
“Ensure ongoing operational, maintenance and replacement costs are affordable”
“Minimise the life-cycle costs for the facility”.
The design development for Rain Bank was very cognizant of the need for “total cost”
effectiveness which included a balance between capital costs and operational costs. A
minimum 2 year operational cycle will be required to ascertain the long term
25
| RAIN BANK FINAL REPORT MAY 2012
effectiveness of the installation and the validity of design and construction decisions
implemented.
“Encourage the local QLD Economy”
As part of the Corporation policy, local contractors, suppliers and connsultants were
utilised wherever possible. E.g. Stornaway, the treatment plant manufacturer was a
Queensland company.
4.2.4 Landscape
“Ensure that the required infrastructure is visually integrated within the Parklands to
minimize intrusive impact whilst remaining “accessible” for public information and
educational purposes” (refer previous comments under 4.2.2 “Social).
‘To develop a landscape solution that maximizes open public space and minimizes
obvious built form”.
The total containment of the SHIP structure below ground level with pavement over,
and location of the SHARC plant and plant room below ground on the site of the former
RBIC building, has ensured a significant enhancement in quantum and quality at
useable open space. The provision of the viewing window to the SHARC within the
rainforest has also maintained accessibility for the public whilst minimizing the physical
impact for the general public.
26
| RAIN BANK FINAL REPORT MAY 2012
4.3
Financial
4.3.1 Funding
Funding for this project has been obtained from both the Federal Government and
Queensland State Government as follows:
Federal Government
Department of Sustainability, Environment, Water, Population and Community
Total funding from Federal Government
$3,300,000
State Government
Queensland Water Commission
South Bank Corporation
$4,600,000
$1,100,000
Total project budget
$9,000,000
Additional funding for post contract works
Provided by South Bank Corporation
$360,000
The remaining financial details have been removed from this document.
27
| RAIN BANK FINAL REPORT MAY 2012
4.4
Production Output
The Rain Bank system was designed to process 77 megalitres of treated storm water
annually. This would equate to appropriately 85% of the Parkland’s requirement for
“non-potable” water. Irrigation is the primary focus for utilization of this new water
source, with water feature top-up and flushing of public toilets also included in this
usage. Priority would however be for irrigation with any “surplus” being directed to
water features and toilets. The site reticulation system established under Rain Bank
included branch lines to all major public toilet installations. The installation of “dual
water supply” reticulation within each toilet installation is being progressively
implemented to take advantage of this alternative supply of flushing water. As the
Corporation has not used potable water for irrigation since 2006, Rain Bank will not
impact on this aspect of potable water usage. It will, however provide for the long
term sustainability of the Parklands landscape and the reinstatement, at least in part,
of the ‘sub tropical’ presentation. The biggest reduction will be in the cost and
inefficiency of tankered re-cycle water.
The supply cost of this alone was
approximately $19.50 per kilo litre without the added time and inconvenience costs of
site wide distribution.
The estimated supply cost of water from Rain Bank is approximately $1.20 per kilo litre
(excluding capital cost issues).
A minimum 12 month operational cycle will be necessary to review and analyse the
availability of and demand for, treated water for irrigation, water features and toliet
flushing. The longer term potential to utilize the treated storm water for at least part of
the pool backwash process in lieu of potable water (subject to satisfying appropriate
health regulations) will also continue to be pursued.
4.5
Other Benefits
The Rain Bank installation will contribute to the improved water quality of storm water
outflow into the Brisbane River. In normal operational mode, up to 77 mega litres of
storm water run-off will be captured and filtered, thus providing supplementary benefits
in reducing potential quantum of pollutants flowing into the river.
A further benefit as a result of the weir installation (SHIP) is the potential to capture
accidental spills that may occur in the catchment upstream of the
SHIP.
The post contract requirements to install “tidal flaps” to the storm water outflow points
to the river, is also anticipated to assist in the reduction of river water ingress into the
storm water system for the catchment area, particularly during a flood event. This
point of view will be the subject of ongoing analysis in conjunction with Brisbane City
Council.
The educational/public awareness of water conservation, the principles of Storm Water
Harvesting and the operational display of Rain Bank were important aspects of the
project since inception. The level of interest from the public and industry group is a
pleasing response to this important part of the Rain Bank installation (refer previous
comments in this regard).
28
| RAIN BANK FINAL REPORT MAY 2012
4.6
Project Experience
Generally, the project has been successfully implemented and, subject to verification
following the completion of the minimum 12 month operational cycle, the overall
project objectives have been achieved.
A summary project overview of key project issues is as follows:

The “Design and Construct” form of contract for SHIP and SHARC structures and the
plant and equipment is considered to have worked very well. This was in part, due to
the skills and motivation of the principle contractor on the project (heavily scrutinized
at tender review) and also the thorough review and compilation of clear design
parameters/requirements by the consultant team in the tender documentation.

In hindsight, the issue regarding tidal ingress and the impact of the City Cat wake on
the SHIP design could have been addressed at an earlier stage of the contract. The
natural assumptions by the consultants and BCC that recent historical tide levels could
be relied upon proved incorrect. Whether it is a result of the 2011 flood event or other
recent causes, the combined effect of the 200-400mm increase in high tide levels and
the 300 mm “tidal surge” resulting from the City Cat Ferry, wash had significant impact
on the operational capacity of the weir. The final design solution to install “tidal flaps”
on the outflows would not have changed significantly, had the issue been identified at
an earlier time, however, the time impact on finalizing the project validation process
would have been much reduced had the issue been identified earlier.

An issue has developed post contract completion with the humidity levels and
temperatures within the SHARC plant room. Whilst the design parameters have
been achieved, a problem with condensation and heat, particularly during summer
months, has caused issues with the educational display monitors. Options to
remedy this are being investigated with a view to implementing a solution within
the next few weeks.
In the mean time, the display screens have been
temporarily removed and stored to prevent damage. The options being investigated
include increased exhaust ventilation and/or partial air conditioning. Minimising energy
consumption will be a significant influence on
29
| RAIN BANK FINAL REPORT MAY 2012
Attachments
30
| RAIN BANK FINAL REPORT MAY 2012
the selected solution.
31
| RAIN BANK FINAL REPORT MAY 2012
SHIP during construction
32
| RAIN BANK FINAL REPORT MAY 2012
Plant Room Interior
33
| RAIN BANK FINAL REPORT MAY 2012
Plant Room Interior
34
| RAIN BANK FINAL REPORT MAY 2012
Plant Room Interior: Outlook
35
| RAIN BANK FINAL REPORT MAY 2012
Plant Room viewing Window
36
| RAIN BANK FINAL REPORT MAY 2012
Plant room viewing window and interpretive signage
37
| RAIN BANK FINAL REPORT MAY 2012
Landscape over tank complete
38
| RAIN BANK FINAL REPORT MAY 2012
SHIP Structure landscape over
39
| RAIN BANK FINAL REPORT MAY 2012
Official Opening of “Rain Bank” on October 24th 2011
40
| RAIN BANK FINAL REPORT MAY 2012