Frequently Asked Questions

Maintenance dredging involves the removal of sediment from the underwater infrastructure where it has collected through natural processes such as wind or wave action.

The Port is required to undertake maintenance dredging of its infrastructure, including the shipping channels, to ensure navigational safety of vessels under the Transport Infrastructure Act 1994.

Without maintenance dredging, navigation channels become shallower, restrict the safe passage of vessels and impact on the efficient operation of the port and associated supply chains.

Maintenance dredging is essential to keep the Port of Townsville operating safely and reliably, supporting the continued movement of fuel, household goods, building materials and vehicles that communities rely on every day, as well as exports that underpin North Queensland’s industries and economy.

The majority of the Port's maintenance dredged material is placed at sea in a designated Dredge Material Placement Area in Cleveland Bay. For the large annual volumes generated through maintenance dredging, sea placement is currently the most practical and feasible management option due to the fine-grained nature of the sediment and the volume of material removed from Port infrastructure each year.

The Port does bring small volumes of suitable dredge material to land for beneficial reuse where operationally feasible (e.g. beach renourishment of Rowes Bay, with Townsville City Council following the 2019 floods).

Annual maintenance dredging generates approximately 450,000m³ of material. Significant land area would be required to contain and dewater this material.

Unlike quarry materials or engineered fill, maintenance dredge material is typically unconsolidated silts, clays and fine sands and is generally unsuitable for land development without significant processing and treatment.

Reclamation would require the permanent conversion of marine areas within the Great Barrier Reef World Heritage Area into land.

While reclamation may be appropriate where there is a demonstrated need for new port infrastructure or operational land, creating ongoing reclamation solely for placement of annual maintenance dredge material is not considered a practical long-term solution.

The current designated sea Dredge Material Placement Area (DMPA) was chosen in 1993 informed by a comprehensive, independent, scientific environmental monitoring program in conjunction with government agencies, Great Barrier Reef Marine Park Authority (GBRMPA), James Cook University (JCU) and Australian Institute of Marine Science (AIMS). 

It is located outside the Great Barrier Marine Park in deep water, located away from sensitive coral reefs and permanent seagrass beds. It’s located in approximately 12–16 metres of water and was deliberately selected to reduce the likelihood of wave-driven sediment resuspension compared with shallower areas of Cleveland Bay.

The DMPA is located withing the Port exclusion area, an area designated by the State and Federal Governments for commercial and industrial port activities.

While an offshore location may provide some advantages associated with deeper water placement, they would introduce dredged material placement activities into previously undisturbed areas of the Great Barrier Reef Marine Park, create new environmental impact pathways and increase operational cost, complexity and uncertainty.

For these reasons, alternative offshore greenfield locations are considered less suitable than the existing offshore placement area.

Further information can be found on the dredge management webpage.

The Port has assessed a range of alternatives, including:

• The option of not dredging;
• Land placement / reclamation;
• Beach renourishment;
• Off-site disposal / landfill use;
• Existing offshore DMPA (Cleveland Bay);
• New offshore greenfield placement area in GBR Marine Park;
• Nearshore placement area; and
• Far offshore (Deep-water placement).

Each option presents different environmental, technical, operational, regulatory and cost considerations.

Further information can be found in the Alternatives section on the dredge management webpage.

The LTMDMP is the Port of Townsville's long-term environmental management framework for maintenance dredging, ensuring that essential shipping access can continue while environmental values, including those of the Great Barrier Reef and Cleveland Bay, are protected and monitored.

Port operates under strict environmental permits and management plans, with oversight from the National EPA and Department of Environment, Tourism, Science and Innovation (DETSI).

Independent programs - including hydrodynamic modelling and water quality assessments - support decision making regarding maintenance dredging and material placement.

These studies focus on the sensitive receptors in Cleveland Bay including Magnetic Island.

These findings and real time water quality monitoring data including around Magnetic Island are publicly available and reflect our commitment to science-based decision-making and environmental stewardship. 

Cleveland Bay is a large, north-facing shallow bay with most of it having a depth of less than 10 metres.

The bay is naturally turbid with areas less than 5 metres deep re-suspending over 200 days a year. Various factors contribute to turbidity levels, including weather events, wind, tides, flooding, cyclones and sediment run-off from creeks and riverways as well as increased urbanisation. Sediment flowing from the Burdekin River can also have a significant impact on Cleveland Bay.

Water quality monitoring undertaken in Cleveland Bay shows that the greatest influence on turbidity in the bay is wind-driven waves.

Water quality impacts from dredging and placement have been modelled and show plumes are temporary and localised.

Further information can be found on Our Environment and Dredge Management webpages.

Approvals to place dredge material in the DMPA are assessed and approved by State (Department of the Environment, Tourism, Science and Innovation (DETSI)), and Federal government departments (National Environmental Protection Agency (NEPA).

Under legislation, all dredge material that is placed in the DMPA must be tested and assessed as suitable for unconfined sea placement against the National Assessment Guidelines for Dredging 2009.

To utilise the DMPA, Port of Townsville is required to hold a sea dumping permit, which is issued by the NEPA.

The current permit for placement of material at the DMPA has been extended until December 2026 with no alteration to the terms or conditions of the permit.

After consulting with the National EPA, no further extension to this permit is possible as the volume it was issued for is expected to be fully utilised in 2026.

In 2026 the Port is applying for a new sea dumping permit for a 10-year period from 2027 to 2037 to continue the placement of maintenance dredge material in Cleveland Bay. This will provide long-term certainty for port operations, customers, supply chains and the general community. This permit period is consistent with other Queensland ports.

The permit application will be for the continued placement of maintenance dredge material in the existing Dredge Material Placement Area (DMPA) location in Cleveland Bay. The Port is not seeking to change or reconfigure the existing DMPA location in this application.

The application will be for 5,650,000m³ for the life of the permit (2027-2037) and a contingency volume of 350,000m³ to be used if required following an extreme weather event (cyclone, flood) to restore safe navigation within the Port of Townsville’s underwater infrastructure.  

A sea dumping permit in Australia is assessed through a structured, evidence?based process set out under the Environment Protection (Sea Dumping) Act 1981 and the London Protocol (an international treaty that covers prevention of marine pollution). The assessment is undertaken by assessment officers within the Sea Dumping Unit of the National Environmental Protection Agency (NEPA*).

Further information can be found at this link How to apply for a sea dumping permit - DCCEEW

* The federal Department of Climate Change, Energy, the Environment and Water (DCCEEW) now operates under the National Environmental Protection Agency and is referred to as National EPA.