Dredging takes place to establish and maintain safe access channels for ships and other vessels at ports or marinas.
Types of dredging
Capital dredging is undertaken to create new channels or enlarge existing ones, as well as berth areas, swing basins, marinas and boat harbour areas.
Maintenance dredging is undertaken to maintain existing port and marina facilities.
Depending on the location along the Great Barrier Reef, dredging and the disposal of dredge material at sea can occur inside or outside the Marine Park boundary.
The Great Barrier Reef Marine Park Authority’s preference is for land-based disposal of dredge material.
Dredging and disposal of dredge material can potentially reduce water quality, change hydrodynamics (the movement of water), smother plants and animals that live on the seabed, and displace marine life.
Disposed material may also move from its original disposal location, transported by wind, waves and tides, and oceanic currents.
Dredging and disposal activities need to be appropriately managed to prevent environmental harm.
Applications for dredging and disposal of dredge material within the Great Barrier Reef Marine Park or World Heritage Area must undergo a comprehensive environmental assessment.
There are also international, Commonwealth and state laws that cover dredging and disposal at sea. These include requirements for evaluating disposal alternatives such as land-based options, as well as waste minimisation, site and impact assessments, and management and monitoring programs.
Within the Marine Park, permits under the Environment Protection (Sea Dumping) Act 1981 and the Great Barrier Reef Marine Park Act 1975 are required for the loading and disposal of dredge material. Approvals for dredging and dredge disposal may also be required under the Environment Protection and Biodiversity Conservation Act 1999. In the assessment and approval of permits, impacts on the Great Barrier Reef must be considered.
A permit application must comply with the National Assessment Guidelines for Dredging 2009, which describe the procedures for sampling, testing and assessing whether material is suitable to be disposed of at sea and the procedures for evaluating and monitoring disposal sites.
Proposed disposal activities must also comply with the 1996 Protocol to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972 (the London Protocol) which sets out guidelines for assessing these proposals.
The London Protocol requires that other alternatives be considered including land-based disposal, recycling, or treatment of the material in a way that doesn’t pose a risk to human health or the environment or involves disproportionate costs. The National Assessment Guidelines for Dredging state if viable alternatives to sea disposal exist, a permit is unlikely to be granted.
Applicants are also required to undertake modelling in accordance with the Great Barrier Reef Marine Park Authority's hydrodynamic guidelines to predict the extent of dredge or disposal-generated sediment plumes.
If a permit is granted, the permission will specify certain conditions, which may include an approved environmental management plan, environmental site supervision and monitoring of water quality and other factors.
The agency has worked with the Australian Institute of Marine Science to compile existing scientific knowledge of how dredging and disposal impacts on the Great Barrier Reef and identify what further research is needed.
The Dredge Synthesis Report, published in March 2015, focuses on physical, chemical and ecological aspects such as how sediment moves, settles and disperses, and looks at the ecological impacts on reefs, seagrass and other key species and habitats.
The Improved dredge material management in the Great Barrier Region project, completed in July 2013, reviewed options for the beneficial reuse and land disposal of dredge material.
It also developed a framework for water quality monitoring and management programs, and assessed potential alternative dredge material placement sites in six study areas along the Great Barrier Reef coast.
The research, funded by the Australian Government and carried out by Sinclair Knight Merz and Asia-Pacific Applied Science Associates, was the first to incorporate the combined influence of waves, tides, local winds and large-scale currents when modelling the movement of dredge material over 12 months at multiple locations.
We also developed an interpretive statement of findings.
- Other policies and guidelines
- Dredging and spoil disposal policy
- Dredging coral reef habitats
- Environment Heritage and Protection — disposing of material in tidal waters
- Memorandum of understanding between The Marine Park Authority and Queensland Ports Association
- National Assessment Guidelines for Dredging 2009
- Hydrodynamic modelling guidelines
Ban on capital dredge material disposal
The Australian Government has established a new regulation that ends the disposal of dredge material in the Great Barrier Reef Marine Park from capital dredging projects such as port developments.
The regulation, under the Great Barrier Reef Marine Park Regulations 1983, came into effect on 2 June 2015.
- The effect of the regulation is as follows:
- The Authority must not grant a permission for conduct that includes dumping of capital dredge material in the Marine Park.
- The ban applies to existing permits for conduct that includes uncontained disposal of capital dredge material in the Marine Park where the permits have yet to expire.
- A regulation impact statement is available for viewing.
The following information details how the ban on the disposal of capital dredge material in the Great Barrier Reef Marine Park will operate.
- What does this mean for existing permit applications?
- It means the Great Barrier Reef Marine Park Authority cannot make a decision to grant permission for the disposal of capital dredge material in the Great Barrier Reef Marine Park.
- What does this mean for future permit applications?
- It means the Great Barrier Reef Marine Park Authority will not be able to permit the disposal of capital dredge material in the Great Barrier Reef Marine Park.
- The Federal Government has put an end to capital dredge disposal once and for all.
- What does this mean for existing permits?
- It means an existing permit for disposal of three million cubic metres of capital dredge material has been revoked and cannot be used by the permittee.
- When did the regulation come into effect?
- The regulation came into effect on 2 June 2015, a day after it was placed on the Federal Register of Legislative Instruments.
- What is capital dredging?
- Capital dredging is undertaken to create new shipping channels or enlarge existing ones, as well as berth areas, swing basins, marinas and boat harbour areas.
- Capital dredging is not affected by this regulation, and can still be considered under a Marine Park permit application, subject to the agency's stringent environmental assessments.
- Capital dredge material does not include amounts from very small scale dredging works (less than 15,000 cubic metres). For example, those associated with constructing an approach to a small boat ramp; material excavated to maintain an existing channel, basin, port, berth or other area for its intended use; or for protecting human life or property.
- Dumping does not include burying a cable, pipeline or tunnel for infrastructure purposes, for example for water, telecommunications or electricity.
- Where has most capital dredge material been disposed of in the past 5-10 years?
- In the past five years, there was one major capital dredging project that involved offshore disposal. This was for the expansion of the Gladstone Port. The material was disposed of in the World Heritage Area, but outside of the Marine Park.
- In the past 10 years, 60 per cent of all capital dredge disposal occurred in the Marine Park. The disposal was associated with two major projects — the Hay Point and Abbot Point port expansions.
- Prior to steps being taken to end the disposal of capital dredge material in the Marine Park, referrals for future capital projects totalled some 29 million cubic metres of dredging over the next decade. Some of these projects had earmarked disposal in the Marine Park as a potential option.
- How is capital dredging different to maintenance dredging?
- Maintenance dredging is undertaken to maintain existing port and marina facilities to provide vessels with safe access.
- Under what circumstances will disposal of dredge material in the Marine Park be permitted?
- Permit applications can continue to be made for disposal of maintenance dredge material.
- We would also be able to consider permit applications for disposal from very small scale dredging works (those resulting in volumes of less than 15,000 cubic metres), for example those associated with constructing a small boat ramp, or reusing sand for beach replenishment.
- All permit applications will continue to be subject to the Great Barrier Reef Marine Park Authority's stringent environmental assessments. They will also need to meet ocean disposal requirements set out in the National Assessment Guidelines for Dredging and requirements under the Environment Protection (Sea Dumping) Act 1981.
- Why is maintenance dredging necessary?
- Maintenance dredging ensures vessels have safe and reliable access to our ports.
- Over time, sand and mud builds up in shipping channels, potentially making them too shallow for navigation. Maintenance dredging removes this material to ensure the channels can be used safely.
- This practice has been occurring at long-established ports for more than a century, meaning a longer-term approach is required to reduce disposal in the Marine Park.
- Through commitments under the Reef 2050 Long-Term Sustainability Plan, we will continue to investigate options for managing maintenance dredge material.
- When did public consultation occur?
- A public comment period was held between 16 March 2015 and 27 March 2015.
- A summary of submissions can be found in the regulation impact statement.