Maintenance Dredging & Sea Placement

Introduction

This document sets-out the terms of a maintenance dredge program at Breakwater Marina, Townsville and is intended to inform readers of the location, need, method, scale and timing of the project.

There is a Link provided at the end of the document for readers to respond to a survey and provide comments and feedback.

Why is there a need to Dredge? 

Townsville is a coastal city with an enviable coastline and a population dominated by on-water enthusiasts. Breakwater Marina is ideally located on the seaward side of Townsville City, at the southern end of The Strand and a short 8 kilometres from Magnetic Island.  It is the Marina of choice for many Townsville and North Queensland leisure boat and charter boat owners with 375 berths and berth sizes ranging from 10m to superyacht lengths of 45m. 

Marinas play a vital role in regional towns and cities, serving not only as storage facilities for vessels but also as destinations for locals and visitors for social and lifestyle connections. Importantly, Marina’s are renowned for their contribution to local economies, serving as essential hubs in the supply chain for marine-related businesses. Marinas facilitate a range of services catering to the needs of boaties and visitors alike, bringing together various stakeholders, suppliers, service providers, charter operators and recreational users. This creates a thriving ecosystem that bolsters local economies and promotes sustainable tourism. 

Fundamental to a thriving Marina hub is having all-tide access so leisure and commercial craft can safely and conveniently navigate in and out of the Marina.

A Requirement under Lease 

Breakwater Marina is required under lease to maintain navigable depths in its access channel and marina basin. Breakwater last dredged these same areas in 2015, restoring original design depths of -2.7m LAT. Hydrographic surveys in 2025 established that natural coastal processes have dropped sediment in the Marina and its access channel and markedly lessened the depth and therefore safe navigation and all-tide access for boats – particularly for large vessels and those with deep drafts.

If the sediments that naturally migrate on the currents in Cleveland Bay and drop in the Marina’s access channel and marina basin don’t get removed, the users of the marina, the surrounding residents, along with locals, business operators, visitors and tourists all end-up with a destination facility they can’t use and which they can’t run a business from.

The Project Scope

The navigable waters within the Breakwater Marina and marina access channel are intended to be dredged to -2.5m Lowest Astronomical Tide (LAT) and -2.0m LAT respectively to safely accommodate a variety of recreational and commercial vessels at low spring tide height.

To achieve this maintenance dredging target, approximately 25,000 m³ of sediment will need to be dredged, made-up of 17,608 m³ from the marina access channel and 7,450 m³ from the eastern side of marina basin.

Maintenance Dredging vs Capital Dredging

It is important to point out that maintenance dredging simply removes accumulated sediment and restores navigable depths that are within the original approved design. This is the intention of Breakwater’s dredge program. In contrast, capital dredging involves the creation of new areas or changes to the approved design of existing areas by deepening or widening

Environmental Assessments & Approvals to Dredge and Dispose of Sediment

Over recent months, Breakwater Marina management has consulted with the Port of Townsville on the need to dredge primarily and to resolve also the options for placement of the sediment. Importantly, Breakwater Marina is land-locked and must rely therefore on the State to provide suitable and environmentally responsible placement locations. Through that consultative phase, it was determined that the sediment was not suitable for beneficial reuse for land reclamation or beach nourishment, leaving the only practicable option to place the sediment at sea at the established Cleveland Bay Dredge Material Placement Area (DMPA).

In 2025, Breakwater Marina engaged a qualified consultant to prepare a targeted Sediment Sampling and Analysis Implementation Report on the nature and quality of sediment to be dredged from the Marina. The dredge material has been assessed and is suitable for both land and unconfined sea placement. 

Where is the DMPA for Sea Placement of Sediment 

The Cleveland Bay Dredge Material Placement Area (DMPA) was established in 1993 and is located between Magnetic Island and Cape Cleveland and around15 kilometres offshore from Townsville. The site was chosen following a comprehensive, independent, scientific environmental monitoring program done cooperatively between government agencies, Great Barrier Reef Marina Park Authority (GBRMPA), James Cook University (JCU) and the Australian Institute of Marine Science (AIMS).

The objective of the site is to avoid sensitive habitats and to allow for natural containment and dispersion. Importantly, the DMPA is not within the Great Barrier Reef Marine Park and is within the Townsville Port exclusion area which is designated by the State and Federal Governments for commercial and industrial port activities.

The designated sediment placement area covers 12 square kilometers, it’s in water up to 16m deep and is purposefully located away from sensitive coral reefs and seagrass beds.   <View> DMPA Placement Map

The placement of dredged material to the DMPA is tightly controlled and subject to environmental approvals from the State and Commonwealth Government. Under legislation, material to be placed at the DMPA must be scientifically tested and meet strict criteria for unconfined sea placement. Breakwater has assessed the material in its project area and its has been endorsed as suitable for sea placement. The prospect of sediment plumes associated with the placement activity has been rigorously considered in the dredge plan and will be detailed in the project specific sea placement permit application. 

Transporting and Placement of the Sediment at the DMPA

The dredge material is intended to be transferred to the approved Cleveland Bay DMPA using a split hopper barge. Approval will be requested from the Regional Harbour Master for vessel movement both within and outside of the Marina.

It is expected that there will be one 1-2 barge movement per day, to and from the Cleveland Bay DMPA. 

Minimising Local Impacts

Our Maintenance Dredging Management Plan (MDMP) guides due care for the local marine environments, primarily through water quality monitoring and adaptive operational controls. The MDMP prioritises seagrass protection by ensuring turbid plumes do not persist or reach an intensity that causes harm. It also provides specific guidance for managing interactions with local dolphins, dugongs and other marine protected species. By adopting conditioned environmental compliance monitoring at the maintenance dredging area and the Dredge Material Placement Area (DMPA) we will be able to demonstrate compliance with State and Commonwealth permit requirements. Ultimately, our broad aim is to deliver the maintenance dredging without causing any environmental harm.

Regarding vessel movements, our MDMP does contain a Vessel Management Plan that addresses the specific vessels and their movement patterns. The project is comparatively small and is anticipated to take no longer than 2 months. This means we can be specific about when we place our material to manage cumulative impacts and all vessel movement will be coordinated with the Port of Townsville and the Harbourmaster.     

Anticipated Timing of the Project

The timing of work will be subject to permit approvals and other factors, and the physical dredging work is expected to take approximately 1-2 month to complete.

The project aim is to commence dredging in the second half of 2026.

Community Consultation

Have your Say...

Breakwater Marina is committed to community engagement as it prepares to deliver a maintenance dredge program in 2026 and invites your feedback on the project proposal.

Maintenance Dredging & Sea Placement Information

 Link to Breakwater Marina Dredge Survey

^{Community Consultation Management Plan 2026}

Breakwater Marina will have its community consultation, with respect to its proposed Maintenance Dredging and Sea Placement program in 2026, open for a period of three (3) weeks.  The Breakwater Marina Dredge Survey will be available to have your say over this three (3) week period.  If you are unable to open the above links, please email [email protected] to request a copy be sent to you.