Maintenance of Inner Harbour underway

Fremantle Ports plans to commence maintenance dredging of the Inner Harbour on 15 April 2024 to remove sediments that have accumulated since capital dredging was undertaken in 2010. 

What is the project?

A total dredge volume of 80,000m3 is proposed to be removed over five years, with 60,000m3 of sediments planned to be removed in 2024, and then approximately 5,000m3 of sediments annually from 2025-29. It is proposed that dredged sediments will be disposed of at the Gage Roads offshore disposal site utilised in the 2010 dredging project.

Why is dredging required?

Maintenance dredging is required to remove sediments that have accumulated in the Inner Harbour from the Swan River estuary since dredging was undertaken in 2010. The dredging will allow safe access for ships into the Inner Harbour, and ensure the berths remain deep enough for larger container vessels. The maintenance dredging footprint remains within the 2010 capital dredging footprint. For context, approximately 2.6% of the volume of sediments removed in 2010 are planned to be removed during maintenance dredging from 2024-29.

Environmental considerations

Fremantle Ports has engaged marine consultants to undertake environmental investigations and assessments including sediment sampling, plume modelling, seagrass mapping, and to develop an environmental management plan including monitoring. Given the small volume and duration of dredging and disposal activities (approximately ten days), the marine consultants have advised that this project presents a low environmental risk. The dredging and disposal operations have been planned to have as little impact as possible to the seabed, water quality, marine fauna, seagrass meadows and social surroundings. Dredging in 2024 is planned to be undertaken in autumn to reduce the impacts on seagrass as their dormancy stage occurs then because of a reduction of sunlight. Modelling predicts plumes will be limited to upstream and the mouth of the Swan River during operations, with turbidity (cloudy water) similar to that experienced during winter rainfall events. Fremantle Ports will not commence dredging until necessary environmental approvals for the project are granted.

Project implementation

Fremantle Ports is committed to engaging with the community and stakeholders throughout the project. Fremantle Ports has completed project briefings with relevant government agencies, Aboriginal representatives, the community and our customers and partners. The details of the project including the Dredging Environmental Management Plan and results of monitoring will be communicated on the Fremantle Ports’ website.

For further information visit Inner Harbour Maintenance Dredging - Environmental Management Plan or please contact Melissa Manns, Senior Environmental Advisor, at [email protected]