2025 review of maintenance dredging of Queensland ports
This review has been prepared by the Queensland Ports Association as part of reporting requirements under the Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports.
Queensland ports require routine maintenance dredging to remove sediments that have accumulated in channels, berths and swing basins due to siltation and sediment transport processes. Most ports cannot sustainably function without maintenance dredging. Maintenance dredging has occurred in Queensland since ports were first established.
Most of Queensland’s maintenance dredging is undertaken by the Trailing Suction Hopper Dredger Brisbane, a specialised dredger owned and operated by Port of Brisbane Pty Ltd. The Brisbane is uniquely designed for Queensland conditions and adheres to advanced environmental management practices. Its environmental safeguards align with the latest Trailing Suction Hopper Dredger technologies, ensuring minimal environmental impact during dredging activities.
In accordance with the Queensland Maintenance Dredging Strategy for Great Barrier Reef Area Ports, a high-level schedule of maintenance dredging activities for 2025 was prepared and submitted to the Department of Transport and Main Roads. This schedule prioritised measures to reduce the scope and footprint of dredging activities wherever feasible, in alignment with government environmental objectives and strategic port management plans.
During 2025, bed levelling was undertaken at Amrun and maintenance dredging was undertaken at the following ports:
This maintenance dredging program for 2025 is now complete (concluding in January 2026 at the Port of Gladstone).
The sections below summarise the outcomes of the 2025 dredging program in relation to timing, volume, and the outcomes of monitoring. Placement options for dredged material were thoroughly evaluated for all maintenance dredging campaigns, consistent with each port’s Long-Term Maintenance Dredging Management Plan and in compliance with relevant state and federal regulatory frameworks.
The outcomes of the 2025 program highlight the commitment of Queensland ports to maintaining navigational efficiency while upholding the highest environmental standards. The sections below aim to support informed decision-making for future dredging activities and policy development, ensuring alignment with sustainable port operations and environmental stewardship objectives.
Amrun
Bed levelling
At Amrun, no dredging occurred in 2025. Only bed levelling occurred at Amrun Port.
All works were compliant with state and federal approvals, and no environmental incidents or complaints were reported.
Environmental assessments
Seagrass
Seagrass populations around Amrun are located within Boyd Bay, outside the area of impact and no monitoring is required under the Long-Term Maintenance Dredging Management Plan.
Water
No vessel-based monitoring is required under the dredging management or environmental management plans based on the volume dredged.
Sediment
A Sediment Characterisation Study was completed in 2023 as per the 5-yearly requirement under the National Assessment Guidelines for Dredging 2009. The sampling confirmed compliance of maintenance dredged material to the National Assessment Guidelines for Dredging 2009 and continued suitability for ocean placement at the current approved Amrun Material Placement Area. A new Sediment Characterisation Study will be completed prior to the 2028 maintenance dredging campaign.
Turtles and dugongs
Visual observations were completed and recorded in dredge logs. No interactions or observations were recorded during dredging or placement operations.
Biosecurity
All vessels underwent a marine pest risk assessment prior to mobilising to site in which all vessels were assessed as low risk. No marine pests were identified during dredging activities.
Port of Brisbane
Maintenance dredging
A total of 344,833m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 1 January 2025 to 19 April 2025 and the Clam Dredger Ken Harvey during June to December 2025. Dredging was undertaken in the Brisbane River.
Activities were fully compliant with all state approvals (Environmental Authority, Marine Park Permit and Allocation of Quarry Material). No permit non-compliances, environmental incidents or complaints were reported regarding maintenance dredging operations or activities.
Environmental assessments
Seagrass
The annual survey was undertaken by BMT from 28 August 2025 to 3 September 2025. The results showed a reduction of seagrass meadows at all sites due the impacts of Cyclone Alfred. A consistent pattern of post-flooding reduction followed by recovery is evident in the data back to the 2011 floods. Also evident is a long-term expansion of seagrass adjacent to Fisherman Islands due to port expansion creating calm and suitable conditions for seagrass meadow expansion. The Port of Brisbane continues to work with various catchment management stakeholders to address the causes of excessive sediment generated in rain events in the Brisbane River catchment.
Water
Triennial dredging turbidity monitoring was last undertaken in February 2023. Reported results were consistent with previous investigations. Plumes remained within both dredging areas and the dredged material placement area and there were no impacts on sensitive receptor sites.
Sediment
The Sediment Sampling and Analysis Plan sampling was undertaken during September 2025. A total of 35 sites were sampled, comprising 26 sample locations within the proposed dredging area and 9 reference locations. Results from 2025 were generally comparable to previous years. Sediments within the dredging zones were found to be suitable for ocean placement in accordance with the National Assessment Guidelines for Dredging 2019.
Turtles and dugongs
No interaction with dredging.
Biosecurity
In January 2020, the marine pest species White Colonial Sea Squirt (Didemnum perlucidum) was first detected at the Port of Brisbane. This species of marine pest has been detected in subsequent sampling campaigns. The Suminoe Oyster (Magallana ariakensis) was detected for the first time as part of the Port of Brisbane Q-SEAS program. This oyster was known to be in the area with the Department of Primary Industries identifying the species previously in the Brisbane River, Boggy Creek, Kedron Brook, Cabbage Tree Creek, the Pine Rivers system, Scarborough Harbour, Caboolture River and Pumicestone Passage.
View Port of Brisbane monitoring reports.
Port of Bundaberg
Maintenance dredging
A total of 108,305m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 22 April 2025 to 2 May 2025. Dredging was undertaken at the berths, swing basins, inner and outer channels.
No permit non compliances, environmental incidents nor complaints were reported.
Environmental assessments
Seagrass
The Port of Bundaberg Long-term Maintenance Dredging Management Plan monitoring for seagrass, benthic and particle size analysis assessment at the offshore Material Relocation Area is undertaken every 5 years with the last survey carried out in 2020. The study showed the presence of a large deep-water seagrass meadow within and outside the Material Relocation Area. No differences were found in seagrass biomass and sediment particle size distribution between inside and outside the Material Relocation Area. Infauna communities were more diverse and abundant outside the Material Relocation Area. However, no relationship with increasing distance from the Material Relocation Area was found. Therefore, the study showed no evidence of dredged material placement impacts on seagrass and benthic communities occurring outside the Material Relocation Area.
The 2025 survey has been completed and Gladstone Ports Corporation Limited is awaiting the final report.
Water
A water quality monitoring program has been designed and implemented prior, during and post maintenance dredging operations to ensure water quality does not deteriorate as a result of maintenance dredging plumes and thus to protect sensitive receptors in the area. Turbidity data is collected in the dredging phase and screened against developed turbidity triggers. The monitoring is paired with a tailored adaptive management framework ensuring appropriate actions are taken when turbidity levels reach the above-mentioned triggers.
No water quality impact was detected from the activity.
Sediment
Sediment quality assessment following the National Assessment Guidelines for Dredging 2009 was last conducted in 2024, with sediments within the dredge footprint found to be suitable for sea placement.
Turtles and dugongs
Direct impacts are mitigated through controls documented in environmental management plans. These include fitting of turtle exclusion devices, visual observations, protocols on when to stop activities, wait, and re-commence activity, and guidance on reporting. Indirect impacts to these species are mitigated through the management of water quality during maintenance dredging activities.
No impacts to marine megafauna were identified from the activity.
Biosecurity
No marine pests identified during activity.
View Port of Bundaberg monitoring reports.
Port of Cairns
Maintenance dredging
A total of 520,870m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane, supported by the bed levelling vessel Pacific Titan from 18 November 2025 to 18 December 2025. Dredging was undertaken at the Port of Cairns Outer Channel and Inner Port.
A total of 8,670m3 of material was dredged by the Grab Dredger Willunga from 21 January 2025 to 24 March 2025 at the Cairns Marlin Marina.
Works were completed under the Port of Cairns 10-year Sea Dumping Permit, Marine Park Permit and Environmental Authority. All dredged material was placed within the approved offshore Dredged Material Placement Area. All works were completed in line and compliant with above-mentioned approval conditions. Volume of material dredged and placed within the Dredged Material Placement Area was within Sea Dumping Permit annual permit limit. No non-compliances were issued in regards to the Port of Cairns maintenance dredging activity by regulatory agencies.
No environmental incidents nor complaints were reported.
Environmental assessments
Seagrass
The annual seagrass survey, part of the Cairns Harbour and Trinity Inlet Long-Term Seagrass Monitoring Program, was undertaken by James Cook University, TropWater, in October and November 2025. Photosynthetically Active Radiation light data surveys continued. Survey results and related report have not been finalised yet.
Water
Water quality verification under the Port of Cairns Long-Term Maintenance Dredging Management Plan or Environmental Management Plan was not required during 2025. The next campaign-specific water quality monitoring is due in 2027.
Sediment
Sediment Sampling and Analysis Plan investigation to assess physical and chemical properties of sediments within loading and disposal sites was undertaken in May 2025 at the Outer Channel, Inner Port, Inner Channel and new swing basins. All material was found to be suitable for unconfined sea placement within the approved Port of Cairns Dredged Material Placement Area. A notable spill occurred on 29 September 2025 within Smiths Creek. Therefore, in consultation with the Great Barrier Reef Marine Park Authority, Ports North undertook additional sampling to ensure sediments within the Inner Port had not been affected by the spill. The sampling showed no evidence that spill-related contamination had reached the Inner Port.
Turtles and dugongs
No interactions or observations were recorded during maintenance dredging or placement operations of the Trailing Suction Hopper Dredger Brisbane.
Biosecurity
Concurrently with 2025 Sediment Sampling and Analysis Plan investigation sampling activities and at the same locations, additional sediment samples were collected. Samples were visually analysed for presence of marine pests. The sampling did not find any suspect or actual marine pest species. Additionally, the Biosecurity Queensland Seaports eDNA Surveillance (Q-SEAS) program also continued at the Port of Cairns in 2025. Samples were collected utilising different techniques (settlement plates and plankton tows) and analysed with molecular and visual techniques. The related report for 2024–2025 did not highlight any suspect or actual marine pest species.
Port of Gladstone
Maintenance dredging
A total of 222,106m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 21 December 2025 to 25 January 2026 and was placed at the Offshore Material Relocation Area. Dredging was undertaken at the berths, swing basins, inner and outer channels.
No permit non compliances, environmental incidents nor complaints were reported.
Environmental assessments
Seagrass
Light is monitored in real time at a seagrass meadow within the zone of influence before, during and after dredging. During the dredging phase, light values as a 14-day rolling average are screened against a light requirement threshold developed through field and laboratory studies. The light monitoring program is incorporated into an adaptive management plan which follows a multi-staged approach for management responses to reduced light conditions as a result of dredging operations to occur before potential environmental harm to seagrass meadows and sensitive receptors occur.
This is supported by a comprehensive annual seagrass monitoring program that assesses the health of seagrass meadows through 3 key metrics: surface area, biomass and species composition.
No impact was detected from the activity with environmental factors such as ambient light levels and tidal state.
Water
Real time turbidity monitoring is undertaken at a compliance and support site whose locations have been determined by maintenance dredging plumes modelling and impact assessment. During dredging, turbidity at the compliance site is screened against developed triggers. Adaptive management steps have been developed ensuring appropriate procedures and actions are undertaken when turbidity reaches such triggers in turn ensuring potential environmental harm from dredging-related turbidity plumes is identified, assessed, prevented or minimised.
No water quality impact was detected from the activity, with environmental factors such as tidal cycles and winds appearing to be the drivers behind turbidity patterns in line with historical data and maintenance dredging campaigns.
Sediment
In line with the Port of Gladstone Long-term Maintenance Dredging Management Plan long-term monitoring schedule and the National Assessment Guidelines for Dredging 2009, sediment quality in the main channels is assessed every 5 years. The sediment quality was assessed in 2022 following the National Assessment Guidelines for Dredging 2009 and found to be suitable for sea placement.
Turtles and dugongs
Direct impacts are mitigated through controls documented in Environmental Management Plans. These include fitting of turtle exclusion devices (where possible) and including visual observation with protocols on when to stop activities, wait, increase visual observations and commence or re-commence activity and guidance on reporting. Indirect impacts to these species are mitigated through the management of water quality during maintenance dredging activities.
No impacts to marine megafauna were identified from the activity.
Biosecurity
As per the Port of Gladstone Long-term Maintenance Dredging Management Plan long-term monitoring schedule, a survey to identify any marine pests within the Port of Gladstone is undertaken every five years. In 2021 and 2022, and again in 2025, Gladstone Ports Corporation Limited in conjunction with the Queensland Department of Primary Industries (previously the Department of Agriculture and Fisheries) carried out monitoring within the harbour. No new species were detected.
View Port of Gladstone monitoring reports.
Port of Karumba
Maintenance dredging
A total of 102,522m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 10 June 2025 to 1 July 2025, supported by the bed levelling vessel Pacific Titan from 12 June 2025 to 2 July 2025. Dredging was undertaken in the channel entrance including the amended alignment for the established navigational area.
Activities were completed under the Karumba 10-year Sea Dumping Permit and Environmental Authority. All works were compliant and consistent with the two above-mentioned approval conditions. The dredged volume was within annual permit limit. No non-compliances were issued in regards to the activity by regulatory agencies.
No environmental incidents nor complaints were reported.
Environmental assessments
Seagrass
The seagrass annual survey, part of the Karumba Seagrass Long-Term Monitoring Program, was completed by James Cook University, TropWater, in October 2025. Outcomes of the annual survey have not been finalised yet. However, preliminary results indicate seagrass conditions remain in a poor status due to multiple and consecutive years of above average river flow and rainfall.
Water
Water quality monitoring was undertaken as per Environmental Authority requirements between 3 June 2025 and 2 July 2025. Turbidity levels during maintenance dredging loading and placement activities remained below turbidity triggers and no maintenance dredging adaptive management measures were required.
Sediment
The latest Sediment Sampling and Analysis Plan investigation was undertaken at loading and disposal sites in May 2025. The results of the Sediment Sampling and Analysis Plan implementation showed sediments were below applicable screening levels and suitable for unconfined sea disposal within the approved Karumba offshore Dredged Material Placement Area.
Turtles and dugongs
No interactions or observations were recorded during maintenance dredging loading or placement operations of the Trailing Suction Hopper Dredger Brisbane.
Biosecurity
Benthic infauna assessment within and surrounding the Dredged Material Placement Area was conducted in May 2025. Results did not report the presence of any suspect or actual invasive species.
Port of Townsville
Maintenance dredging
A total of 348,839m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 7 July 2025 to 3 August 2025. Dredging was undertaken in Platypus Channel, outer harbours, inner harbour and authorised berth pockets.
Observations were conducted on board the Brisbane during the dredging campaign. No non-compliances nor environmental incidents were reported.
No complaints were received by the Port of Townsville Limited during the 2025 dredging campaign. Several queries received after the campaign were responded to by the Port relating to sea placement of dredge material in Cleveland Bay. Port of Townsville Limited understands concerns about dredging activities and material placement may have been made to other stakeholders and that concerned parties were advised to formally contact the Port.
Environmental assessments
Seagrass
Seagrass monitoring within Cleveland Bay was undertaken September to November 2025. The report will be made available on the Port’s website once finalised in early 2026.
Water
The Port of Townsville conducts quarterly marine water monitoring within the Port and the surrounding environments. The Port also had 5 benthic (sea floor) and 2 surface water quality real time buoys deployed in Cleveland Bay throughout the year. While the Port endeavours to provide data throughout the year, severe weather events and maintenance mean that the equipment is unavailable occasionally. During the 2025 maintenance dredge campaign, one buoy was experiencing a loss of data due to equipment damage and was offline during the campaign. During this time, the Port provided a link to data from its benthic turbidity and light sensors located in Cleveland Bay while the buoy was being repaired. Regular analysis of the real time water quality and satellite imagery was undertaken before, during and post-dredging. Data from these buoys is available on a water quality dashboard on the Port’s website.
Marine water data has also been provided for the Healthy Waters Partnership for Dry Tropics Annual Report Card. The 2025 Report Card is based on monitoring data from the previous year, collected from July 2023 to June 2024.
Sediment
Sediment Quality assessment following the National Assessment Guidelines for Dredging 2009 was last conducted in 2021 (plus a supplementary sediment assessment in 2024) with sediments within the dredge footprint found to be suitable for unconfined sea placement excluding 4 berth areas and Ross Creek which require land placement.
The Port is currently in the process of completing a new sediment assessment for all areas that require maintenance dredging, as per the requirements under the National Assessment Guidelines for Dredging 2009.
The Port of Townsville conducts biannual marine sediment monitoring within the Port and the surrounding environments. This grab sampling aids in monitoring sediment between the 5-yearly sediment assessment programs.
Turtles and dugongs
Marine fauna visual observations were undertaken during dredging and placement, as per the Port’s permit conditions, and the dredge Environmental Management Plan requirements. No impacts to marine megafauna were identified from the activity.
Biosecurity
Port of Townsville partners with Biosecurity Queensland and other Queensland Port Authorities on the Queensland Seaports eDNA Surveillance (Q-SEAS) marine pest monitoring program. The White Colonial Sea Squirt continues to be sighted in Townsville waters and around Port infrastructure. View further information on the White Colonial Sea Squirt in Queensland.
All vessels underwent a marine pest risk assessment prior to mobilising to site in which all vessels were assessed as low risk. No marine pests were identified during dredging activities.
View Port of Townsville monitoring reports and Cleveland Bay buoys data.
Port of Weipa
Maintenance dredging
A total of 405,000m3 of material was dredged by the Trailing Suction Hopper Dredger Brisbane from 8 May 2025 to 8 June 2025. Dredging was undertaken at the South Channel, inner harbour and berths.
Activities were compliant with state and federal approvals.
Bed levelling was also undertaken at the Humbug Terminal and Hey River Terminal
No environmental incidents nor complaints were reported.
Environmental assessments
Seagrass
Annual seagrass monitoring was conducted in the Port of Weipa during October 2025. The report will be made available on North Queensland Bulk Ports Corporation’s website once finalised.
Water
North Queensland Bulk Ports Corporation completed ambient marine water quality monitoring prior to, during and post-maintenance dredging program. Data from the water quality monitoring as well as satellite-derived turbidity data was analysed.
The data showed that during the 2025 maintenance dredging program, the turbidity was generally driven by the natural conditions (tidal currents and wind or wave conditions). The Port of Weipa 2025 maintenance dredging program did not influence the regional turbidity of the area.
A summary of the turbidity monitoring is available online.
Sediment
A Sediment Characterisation Study was completed in January 2023 as per the 5-yearly requirement under the National Assessment Guidelines for Dredging 2009. The sampling confirmed compliance of maintenance dredged material to the National Assessment Guidelines for Dredging 2009 and continued suitability for ocean disposal at the approved Albatross Bay Dredged Material Placement Area.
Turtles and dugongs
Visual observations were undertaken and recorded in dredge logs. One sighting of a marine turtle was recorded at the dredged material placement area on 26 May 2025.
Biosecurity
No new marine pests identified during activity.
Specific management measures were implemented during dredging activity at Weipa to minimise the incursion of marine pest species as part of the Dredge Environmental Management Plan.
- Last updated
- 29 June 2026