Awards for Excellence – 2016 NSW Winners
EXCELLENCE IN INFRASTRUCTURE
Cardno Pty Ltd and Scentre Group – Managing Flooding of Warringah Mall in Brookvale
EXCELLENCE IN INTEGRATED STORMWATER DESIGN (Co-winners)
WaterNSW and Blue Mountains City Council – Leura Falls Catchment Improvement Project
City of Sydney, Turf Design Studio and Environmental Partnership – Sydney Park Water Re-Use Project
EXCELLENCE IN POLICY OR EDUCATION
Bankstown City Council – Stormwater Audit and Education Program
EXCELLENCE IN RESEARCH AND INNOVATION
Managing Flooding of Warringah Mall in Brookvale
Cardno Pty Ltd and Scentre Group
Warringah Mall is a regional shopping centre located within the Brookvale Creek catchment in the Sydney’s northern suburbs. Studies in 2006, 2007 and 2008 identified that under existing conditions Warringah Mall is flooded by overland flows and overflows from Brookvale Creek. The 1D/2D modelling approach that was adopted to assess existing flooding problems and structural options including a major drainage augmentation through Warringah Mall is outlined.
A major stormwater augmentation scheme within the Warringah Mall site was developed, assessed and approved with conditions by Warringah Council. One of the conditions of consent required a physical model study of the two large junction boxes to confirm the hydraulic losses which were assumed in the computer model studies and to provide advice on how the hydraulic losses in each junction box can be minimized. This physical model study is described.
A comparison of the predicted and observed hydraulic losses and flood levels concluded that the current numerical 1D/2D model results appear to be conservative in comparison with the physical model results (which may be due to differences in adopted conduit roughness values in the numerical model and the roughness of the conduits in the physical model) and that the flood levels estimated by the numerical model are likely to be conservative.
The photos show one of the modelled culvert configurations during testing and the 1st stage of culvert construction.
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Leura Falls Creek originates in an urbanised sub-catchment (Leura), flows through the Blue Mountains World Heritage Area and drains to Sydney’s drinking water supply at Lake Burragorang.
This project included construction of 11 hard and soft stormwater structures contained within the Leura Falls Creek catchment. The catchment being treated covers an area of approximately 230 ha which largely comprises residential, commercial and light industrial zones that are fully developed with some disturbed native bushland contiguous with riparian zones that drain the catchment.
The treatment structures have been designed to effectively treat key contaminants to the drinking water catchment, nitrogen, phosphorus and suspended sediments. The structures have been selected for ease of operation and maintenance, effectiveness at removing nutrients and suspended solids whilst being sympathetic to the natural environment. One of the objectives was to make it difficult to distinguish where the natural environment ends and the treatment structures begin.
The photos show the treatment structures at Kanimbla Street Leura just after construction and 12 months after construction.
Much has been achieved over the past two decades to transform the Sydney Park site from its former post-industrial history and waste disposal, into 44 hectares of parkland and a vital asset for the growing communities of Sydney’s southern suburbs.
This project forms the City’s largest environmental projects to date, built in partnership with the Australian Government through the National Urban Water and Desalination Plan. It is an integral component of Sustainable Sydney 2030; targeting 10% of water demand to be met through local water capture and re-use in the park. The City also seized the once in a lifetime opportunity to use what was essentially an infrastructure project to breathe new life into the park – as a vibrant recreation and environmental asset for Sydney.
The City engaged a design team led by landscape architects Turf Design Studio and Environmental Partnership (TDEP) who orchestrated an intense and multi-disciplinary collaboration intersecting design, art, science and ecology – in a ‘roundtable’ of creatives shared between water experts Alluvium, artists Turpin + Crawford, ecologists Dragonfly Environmental, engineers Partridge and the City’s own Landscape Architects. Design Landscapes constructed the project.
The result is an interwoven series of community infrastructures and ‘made’ systems – water re-use, recreation, biodiversity and habitat all integrated within the physical fabric of Sydney Park. Sydney Park now offers an enhanced recreational experience to the Sydney community, going beyond the picturesque; creating instead a revitalised, multi-faceted waterscape that celebrates the connection between people and place.
After an intensive process of ‘easing in’, the water re-use project is now fully operational and intrinsically linked with its park setting. The bio-retention wetlands not only captures and cleans the equivalent measure of 340 Olympic-sized swimming pools worth per annum, but successfully improves local water quality, habitat and reduces potable water consumption in the area. The park’s fauna and flora is thriving, with new habitats created and existing ones protected and enhanced throughout the park.
The function and processes of water harvesting and cleansing is enhanced through its visible ebbs and flows through the landscape.
New pathways intersect the wetlands, allowing park users to explore and discover ‘moments’ in the landscape that can be at times playful, dramatic and peaceful, but at all times connected to the water narrative of capture, movement, and cleansing.
Highlighting these processes was an important part of the project, as they emphasise the intrinsic relationship between water, people, topography, flora and fauna. Public art is interwoven; Turpin + Crawford’s ‘Water Falls’ celebrates clean water release while also working with TDEP’s cascades to aerate water in the last link in the bioremediation treatment train. Turpin + Crawford also devised the water ‘exhaust fans’ celebrating the transfer of water from bioremediation ‘paddies’ to the lagoons; playing on the spirit of water and its interactions with topography, form, surfaces, plant life and fauna.
A selection of Instagram pictures from Sydney Park.
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Since 2008 the Stormwater Audit Program of Bankstown City Council, in Sydney’s south west, has engaged commercial and industrial business operators in preventing stormwater pollution, operating under the Protection of the Environment Operations Act 1997 (POEO Act).
The function of the program is to assist business owners to understand their environmental responsibilities and minimise their environmental impacts. The focus of the program is to prevent stormwater pollution and to identify stormwater harvesting and re-use opportunities.
The program has provided a number of benefits, including:
- Increased environmental awareness for business owners
- One-on-one conversations reaching business owners who would not normally have access to the information that the audit provides
- A walk-through of each site to providing insight into business operations
- Controls implemented by businesses minimising the possibility of pollution occurring in the future
- A significant amount of liquid and solid pollution stopped from entering the stormwater system.
The program has employed the principle that sustained behaviour change will be more likely the result where businesses are adopting stormwater pollution prevention to enhance their business as an aspect of best practice. As such, the programs approach is different to one that relies solely on compliance. Working closely with business owners, looking at their activities that cause (or could cause) pollution, and providing support, information and assistance, equips them to make effective and lasting change.
The program provides local businesses with knowledge, information and guidance to make effective and lasting changes to reduce the environmental impacts of their business operations, with a focus on stormwater pollution. The program also assists businesses to identify stormwater harvesting and re-use opportunities.
As of 2015, a new approach has profiled businesses according to the risk of their operations to water quality in receiving waterways. High risk businesses (e.g. automotive mechanics) receive a full audit under POEO Act. Low risk businesses (e.g. hairdressers) receive a less formal approach with an education visit.
An audit involves an introductory meeting to discuss business operations and the operators understanding of POEO Act. The operator and auditor then tour the facility and any POEO Act non-compliances are discussed. The operator generally describes the business processes and associated issues are discussed which include staff training, spill clean-up procedures, liquid storage and disposal, and waste management. Following the audit, possible rectification works and timeframes are discussed. A letter is sent, including a schedule of works and a tailored information pack. Once compliant, a certificate of completion is issued.
An education visit involves a shorter meeting in which the auditor discusses business activities which have the possibility of pollution (e.g. mop water disposal and car washing) and provides general information on what constitutes pollution, what the difference is between stormwater and sewer, and the POEO Act.
In 2015, 448 business operators were engaged by the program and 247 audits were conducted, with 84 businesses having non-compliances identified. Business operators have noted their appreciation of various components of the Program, with many welcoming Council to their sites to provide a step by step understanding of their responsibilities. Others expressed appreciation for local waterways and respect for what the program has achieved. In some instances, businesses have demonstrated improved efficiency and cost savings through changes instigated by the program.
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WaterNSW (WNSW) identified, using the Pollution Source Assessment Tool, that the risk to water quality from stormwater is a key contributor to the pollution risk in the urban areas of Sydney’s Drinking Water Catchment (SDWC). Pollution sources have remained unidentified due to the diffuse nature of stormwater pollution. Typically pollution is intermittent and diverse in nature. This presents significant difficulties when using traditional methods to sample and analyse for pollutants. The difficulties include the cost and potential to miss pollution events.
The Centre for Aquatic Pollution Identification and Management (CAPIM) have developed technologies and an innovative process to identify the source of stormwater pollution in a cost effective, timely and resource efficient manner. WNSW and CAPIM carried out a stormwater pollution investigation using this new methodology of passive sampling and sourcing techniques in two areas of the SDWC. Passive samplers were deployed at key nodes in the stormwater infrastructure and receiving waterways to determine the presence/absence or concentrations of a particular pollutant. This resulting data allowed WNSW to narrow down the pollution sources to a small number of premises even if the pollution is intermittently discharged.
WNSW partnered with Blue Mountains City Council (BMCC) and Wollondilly Shire Council (WSC) to investigate two areas: Leura Falls Creek Catchment and Werriberri Creek Catchment. Poor water quality has been previously observed within these catchments and was suspected to be due to stormwater runoff, though never successfully investigated. This investigation examined the nature and extent of pollution to enable catchment managers to identify pollution issues and respond using the most appropriate response.
The objectives of the pilot study were: to test the methodology and assess suitability for further deployment and to find and address pollution sources in target areas.
In both study areas high Escherichia coli and human Bacteroides were detected at some sample locations, indicating that the cause could be from sewerage leaks/overflow, on-site sewage management systems or illegal sewerage connections to the stormwater network. This study has identified a specific area where the pollution is originating and will require further follow-up to pinpoint the exact cause of the pollution. Organic contaminants and elevated pesticide concentrations were also evident in the Leura Falls Creek catchment at levels that may pose a risk to aquatic ecosystem health. The approach for addressing the stormwater pollution can include a combination of education, compliance and grants from WNSW and Council depending on the source and cause of the pollution.
A review of the stormwater pollution technology has concluded that it is effective and a forward program that extends the program to other councils is being developed.