Nuclear Submarines in Cockburn Sound: What’s Really Happening Beneath the Surface

While much attention around Cockburn Sound centres on the proposed new container port, several other developments require close monitoring. Among these are upgrades to HMAS Stirling on Garden Island, aimed at hosting nuclear-powered submarines (SSNs) from 2027 and developing an Australian fleet of SSNs by the early 2030s.

Last month, the Department of Defence applied to the Department of Climate Change, Energy, the Environment, and Water (DCCEEW) for environmental assessments under the Environment Protection and Biodiversity Act 1999 (EPBC) for some of the necessary development works.

To support the nuclear submarine program, several priority works have been identified for HMAS Stirling, including:

  • Upgrading and dredging of Diamantina Pier
  • Constructing a new pontoon at Careening Bay
  • Dredging the Explosive Ordnance Loading Wharf
  • Building facilities for radiological controls and radioactive waste management
  • Constructing a power station and pure water processing plant

The Department of Defence has divided these works into three elements. Their recent environmental application covers only part of the development, effectively masking the project’s full impact. Nevertheless, the first phase involves marine infrastructure works, including dredging at Diamantina Pier, the ordnance loading wharf, and Careening Bay, involving:

  • A 6.62 ha disturbance area
  • Piling, fender panel, and pontoon installation from April to September 2025
  • Dredging 19,500m³ starting in March 2026
  • Disposal of dredge waste within Cockburn Sound
Imagine one of these cruising past your ‘yak or skiff!

The Department of Defence acknowledges potential environmental impacts, including:

  • Construction Activities: Noise, vibration, and turbidity from dredging and piling, impacting marine fauna (e.g., little penguins), seagrass, and water quality.
  • Operational Activities: Noise, lighting, and vessel movement from small craft berthing affecting marine life and seabirds.
The Department of Defence admits the Sound’s precious sea beds will be impacted by the development.

As part of the AUKUS agreement with the UK and US, this application is expected to secure environmental approvals. Although the disturbance area and dredging volume are small compared to the new container port, the works will likely impact Cockburn Sound’s environment and represent one of many planned developments.

All projects should be assessed for their total and cumulative impacts on Cockburn Sound. A comprehensive approach to environmental assessment is needed to prevent the gradual industrialization of this community resource.

To track the progress of the environmental application for this aspect of AUKUS, visit the DCCEEW website or click HERE.