Smarter Cleaner Sydney Harbour
Stormwater pollution is a significant problem for coastal waterways and the wider marine estate. Pollutants such as litter and sediment are washed off urban areas during rainfall and conveyed via the stormwater drainage network to receiving waterways. This pollution is not only unsightly but a threat to marine life and public health.
Trapped litter in Duck Creek, Granville (Source: SCCG)
A community survey conducted as part of the development of the NSW Marine Estate Management Strategy identified stormwater as the greatest threat to the marine estate. Similarly, stormwater pollution was identified as the highest priority threat to Sydney Harbour as part of the scoping of the Greater Sydney Harbour Coastal Management Program.
This problem has long been acknowledged. In response, local councils and other stormwater managers have for many decades installed gross pollutant traps (GPTs) on the stormwater network to trap pollutants before they reach the waterways. There are several thousand GPTs now in operation across Sydney and more continue to be installed.
Trash rack style GPT (Source: Stormwater NSW (2020), Guidelines for the maintenance of stormwater treatment measures)
Stormwater treatment technology has evolved considerably in this time. GPT maintenance practices, however, continue to rely on physical inspections and fixed schedules that determine when GPTs are cleaned, irrespective of how full the GPT actually is. That is, cleaning may occur before the unit is full, leading to higher maintenance costs, or may occur after the unit is full, meaning pollution may have bypassed the GPT.
Cleaning of a below-ground GPT (Source: Stormwater NSW (2020), Guidelines for the maintenance of stormwater treatment measures)
Improving GPT maintenance practice through smart technology
Sydney Coastal Councils Group (SCCG) and Parramatta River Catchment Group (PRCG) in partnership with CSIRO and the Sydney Olympic Park Authority (SOPA), recently completed an innovative trial of self-monitoring, analysis and reporting technology (SMART) to improve how GPTs are deployed and managed. This trial involved:
Waterway cameras: Outdoor trail cameras were installed over waterways to take video footage of floating litter. This footage was subsequently analysed using artificial intelligence (AI) machine learning technology to provide data on litter types, quantities, and sources.
GPT sensors: Low cost, low power networked sensors were installed in GPTs to report on the quantity of pollutants collected.
Decision support tool: A tool comprising a computational model, user interface and message notification system, was developed to analyse input data such as flow, GPT capacity and resource availability to help stormwater managers determine the optimum time and resources to clean a GPT.
Five councils are involved in this trial: Northern Beaches, Woollahra, Blacktown, City of Parramatta and Canterbury-Bankstown. Channel 7 recently featured the Smarter Cleaner Sydney Harbour. Watch it here!
The project was supported by the NSW Smart Places Acceleration Program with a $545,000 grant from the NSW Digital Restart Fund. SOPA acted as the NSW state agency project co-partner given Sydney Olympic Park has one of the highest concentrations of GPTs in Sydney.
Some 36 battery operated cameras were installed by SCCG and council staff across five local government areas and Sydney Olympic Park between July and October 2023. Approximately 12 terabytes of video data were collected over five to six months and subsequently analysed using an AI machine learning model. The model was trained to recognised 24 categories of floating litter and 10 material types. Plastic packaging and polystyrene was the dominant litter type however only 1% of images analysis contained litter. However, these data need to be correlated with rain events during which litter captured in the catchments is released. This would determine how representative the data are regarding the relatively cleanliness of urban waterways around Sydney Harbour.
Some 21 low-power sensors utilising long range, wide area network (LoRaWAN) technology were installed in GPTs across four LGAs and Sydney Olympic Park, together with 10 network gateways. Unfortunately issues arose with the connection between the LoRaWAN sensors and network gateways preventing collection of any meaningful data. Some 16 additional sensors using 4G mobile phone technology were subsequently installed with collected data showing GPTs increasing in fullness.
Finally, a decision support tool was developed that sought to analyseis and optimise factors such as flow predictions, initial GPT fullness, resource availability and budget to predict the optimum time to clean a GPT.
The project has successfully concluded. CSIRO is now looking for opportunities to undertake a larger trial at other locations across Australia.
Examples of installed waterway cameras (left) and GPT sensors (right)
The City of Sydney partnered with The University of Sydney’s Centre for Research on Ecological Impacts of Coastal Cities and the Royal Botanic Gardens & Domains Trust to create an aquatic corridor along the seawall foreshore of the City of Sydney local government area. This project delivered 
Bush regeneration contractors were engaged to remove weed species & encourage regeneration of native species in Gore Creek Reserve, focusing on endangered Littoral Rainforest and surrounds. Weed species to be controlled in the reserve included: ground asparagus, morning glory, madeira vine, Ehrharta, Trad, Privet & Ochna. Gore Creek Reserve Bushcare group and others have worked alongside the contractors with the aim of restoring bushland adjacent to their work sites. This project has been successfully completed and the legacy of the project will be maintained in the years to come through Lane Cove Council’s commitment of ongoing designated operational budget for the area, as well as the efforts of the local BushCare groups.
The North Palm Beach Dune Rehabilitation project rehabilitated 5.9ha (50% more than target) of highly degraded coastal dune within the North Palm Beach dune system. Managing weeds in the target site was important in tackling what was a reservoir of weeds threatening other rehabilitated and remnant vegetation. Over 5,000 native tubestock were planted. Completion of this project has reconnected a well-functioning native ecosystem and improved cological linkages between remnant native vegetation. This grant project has now been successfully completed and the legacy of the project will be maintained in the years to come through Northern Beaches Council’s commitment of ongoing designated operational budget for the area, as well as the efforts of local BushCare groups.
The project addressed major weed infestations within the project area. Two EECs were targeted: Themeda Grasslands on Coastal Headlands and Littoral Rainforest & Coastal Vine Thickets. Revegetation at 3 sites controlled exotic grasses at South Bilgola Headland, providing littoral restoration of the Bilgola Creek and restoring Coastal Clay Heath within an area heavily invaded by bamboo. A 
This project has brought together 11 physically connected Councils (Bayside, Cumberland, City of Canada Bay, City of Canterbury Bankstown, Georges River, Inner West, Randwick, Strathfield, City of Sydney, Sutherland Shire & Waverley) and Royal Botanic Gardens Sydney (RBGS) to coordinate a regional approach to fox management through a Fox Control Working Committee. SSROC have taken over management of this Committee to continue its work. A web portal, 
The Waverley Council LGA has lost 99% of the remnant vegetation that was present before European Settlement. This project is part of a larger effort by Waverley Council to halt this loss and improve the condition of the remnant from the current 4% up to 40% by 2020. To implement Council’s newly adopted 
and a reduction in invasive weeds, particularly along the coastal cliff-top heath vegetation communities. In combination with revegetation plantings the outcome has been an increased in size and resilience of the remnant vegetation communities. This grant project has now been successfully completed and the legacy of the project will be maintained for at least the next five years through Waverley Council’s commitment of ongoing designated operational budget for the area, as well as through the efforts of local BushCare groups.
The project has improved connectivity between three zones located along the Lane Cove R. starting from the Fullers Rd bridge next to the Lane Cove National Park moving south through O.H. Reid Reserve, the Chatswood Golf Course and Mowbray Park. Work primarily consisted of invasive weed removal to allow natural regeneration of indigenous species and this was supplemented with some plantings of indigenous plants to strengthen connection of work zones and other saltmarsh areas along the Lane Cove R. Willoughby City Council matched the contribution from Sydney’s Salty Communities grant to deliver this important project to rehabilitate this impacted ecosystem. 2,600 native tubestock were planted (800 more than target) and 8.9ha of weed treatment was undertaken. This grant project has now been successfully completed and the legacy of the project will be maintained in the future through Willoughby Council’s commitment of ongoing designated operational budget for the area, and the ongoing relationship they have developed with Chatswood Golf Club.
Through this project, waste oyster shell collected from commercial farms were processed and arranged to protect eroding riverbanks and to stabilise riparian and coastal vegetation. For the purposes of the Salty Communities Program, erosion control and vegetation enhancement is the primary objective. The project was carried out on behalf of 4 councils – Willoughby, Lane Cove, Sutherland Shire and City of Ryde, and involves education, with community groups engaged in reef building activities. Macquarie University is currently undertaking research into the performance of different oyster reef structures, & will build these project sites into their research program. 
Located in the Woronora River valley area (Woronora to Heathcote), the project has reduced the impacts of aggressive weed species, Weeds of National Significance & Key Threatening Processes on threatened flora and fauna species & three Endangered Ecological Communities of Coastal Saltmarsh, Swamp Oak Flood Plain Forest & Swamp Sclerophyll Forest on Coastal Floodplains. The activities have enhanced the 9 sites’ native biodiversity, increase public empowerment/knowledge and ensure past inappropriate urban development is ameliorated to ensure the ecosystem health of one of Sydney’s most unique Riverine systems. The project significantly exceeded its targets: pest management was undertaken in over 200ha of bushland (44% above target); weed treatment was implemented in 85ha (21% above target), and; over 2,100 native tubestock were planted (114% above target). This grant project has now been successfully completed and the legacy of the project will be maintained for at least the next ten years through Sutherland Shire Council’s commitment of ongoing designated operational budget for the area, as well as its long-term Woronora River Management Plan.
The remnant canopy of Balls Head has been affected by termites which appears to be having a serious ring-barking effect on many of these trees. To avoid generational loss of canopy this project involved research to compare treatment of arboreal termites (Nasutitermes walkeri) with appropriate control sites to compare tree responses and determine cause and effect for poor tree health. There has been a formalised monitoring regime, implemented by the 
This project supported an ongoing whole-of-lagoon approach, by focussing on the southern area of the refuge through restoring saltmarsh, creating habitat linkages and controlling vertebrate pest animals. This project has • Reduced the spread of high priority weeds; • Promoted a backyard habitat and garden escapes program; • Promoted the DY Fauna Fair as a celebration of the Wildlife Refuge for lagoon users; • Established a native seed bank using provenance from Dee Why Lagoon and neighbouring lagoon systems; • Produced a condition map of the bushland and saltmarsh, including mapping tree hollows. This project complements the ‘Dee Why Lagoon Wildlife Refuge Habitat Restoration Project’, a three year program funded through Environmental Trust.
This project aimed to control the growth and further spread of Salvinia, a water weed currently choking Warriewood Wetlands EEC, through introduction of cyrtabagous weevil. Prior to introduction, mechanical and physical weed treatment was planned, to reduce Salvinia cover to improve the probability of successful establishment of the weevil. However due to storm events, a large amount of Salvinia was washed away, delivering considerable savings for the project in mechanical clear. Unfortunately, subsequent storms also washed away many weevils. A 
This project restored a section of coastal remnant vegetation located on the Manly Scenic Walkway in Clontarf. The project site was comprised of Littoral Rainforest, listed in NSW as an Endangered Ecological Community. The works removed invasive species and revegetated with local provenance plants. The project site also has cultural significance, with several Aboriginal middens present. This afforded the opportunity to engage with the Aboriginal Heritage Office to develop a restoration project which enables the vegetation communities to be improved, whilst protecting culturally significant sites and developing interpretive signage and other educational elements. A community engagement program built the capacity of residents to value the local biodiversity and to engage with backyard habitat and garden escapes programs and undertake voluntary restoration activities on surrounding private properties.
This project engaged and tought community members to record the attributes of hollows and trees, and to monitor wildlife use of hollows. It has deliverd 
The project has delivered an improved wildlife corridor linking Endangered Ecological Communities of Curl Curl potentially affected by climate change, to the coastal corridor of Freshwater/McKillop Park, using the assistance of community and corporate volunteers and professional workers. Over 4,000 native plants, of over 30 different species, have been established to replace areas once degraded by Weeds of National Significance (WoNS) and other environmental weeds. A percentage of plants have been propagated from flora further north of this area, to improve climate change biodiversity resilience.
For the 23 Councils within the Sydney Coastal Councils Group (SCCG) and the Southern Sydney Region of Councils (SSROC) (including Ashfield; Bankstown; Burwood; Botany Bay; Canada Bay; Canterbury; City of Sydney; Hornsby; Hurstville; Kogarah; Leichhardt; Manly; Marrickville; Mosman; North Sydney; Pittwater; Randwick; Rockdale; Sutherland; Warringah; Waverley; Willoughby; Woollahra) existing mapping of habitat corridors, have been consolidated into one GIS layer, to identify opportunities for connectivity and contiguity across Council boundaries. 
The CSIRO SCCG partnership project, the 
A reference group was convened for the program, to provide further specialist technical input, guide and/or undertake research, review prioritisation and critique/evaluate sub-projects during development and execution. Expertise in Sydney’s coastal ecosystems, ecological restoration, urban biodiversity and organisational capacity-building provides critical advice to achieve project outcomes.
