AECOM Australia Appointed to Lead Critical Environmental and Site Characterisation Studies for WA’s $25B Henderson Defence Precinct

Overview

The Australian Government’s announcement regarding the Henderson Defence Precinct represents a significant milestone in national infrastructure planning and environmental risk management. AECOM Australia has been appointed to lead the critical environmental and site characterisation studies for Western Australia’s 25 billion dollar defence precinct, marking a highly structured, proactive approach to managing complex environmental liabilities. Funded by a 127 million dollar federal planning and feasibility commitment, this initial phase will lay the essential groundwork for the construction of a future naval shipyard. For Australian environmental professionals, developers, infrastructure lawyers, and local councils, this massive undertaking illustrates the critical importance of extensive, multi-disciplinary baseline studies on high-value, highly sensitive coastal projects.

Cockburn Sound, where the Henderson Defence Precinct is situated, is a marine environment of national ecological significance that is also bordered by some of Western Australia’s most intensive industrial activity. Balancing the development of a state of the art naval shipyard with the preservation of local marine ecosystems requires an unprecedented level of scientific rigour. This project highlights a growing regulatory and corporate expectation: that major infrastructure works must fully define and mitigate environmental risks before a single spade touches the ground. By separating the feasibility and site characterisation phase from active construction, the Australian Government is establishing a clear precedent for mitigating financial, legal, and ecological risks.

For practitioners nationwide, the Henderson project serves as an instructive case study in risk allocation and project design. In an era where environmental litigation is on the rise and regulatory scrutiny is at an all-time high, the consequences of inadequate site characterisation can be catastrophic. Whether dealing with municipal infrastructure, commercial port expansions, or large-scale coastal redevelopments, the integration of environmental science into the earliest phases of project planning is no longer optional. It is the foundation upon which successful regulatory approvals, financial close, and community trust are built.

Key details

The technical scope of the studies led by AECOM Australia is exceptionally broad, encompassing more than 20 individual engineering, environmental, and marine studies across the Cockburn Sound region. The 127 million dollar federal funding allocation ensures that these studies can be conducted with the high level of spatial and temporal resolution required for a development of this scale. A primary focus of these investigations is the establishment of a comprehensive baseline of physical, chemical, and biological conditions across both the terrestrial and marine environments of the precinct.

Given the long history of industrial and maritime activity in and around Cockburn Sound, sediment quality assessments are a critical technical component of the environmental scope. Industrial contaminants such as Per- and polyfluoroalkyl substances (PFAS), heavy metals (including copper, lead, zinc, chromium, and historical tributyltin), and polycyclic aromatic hydrocarbons (PAHs) must be mapped in three dimensions across the seabed. This requires extensive sediment core sampling and physical-chemical profiling to determine the depth and lateral extent of any historical contamination. Understanding the distribution of these contaminants is essential for designing dredging protocols, evaluating disposal pathways, and protecting benthic communities from exposure during construction.

To complement the sediment investigations, AECOM Australia will oversee sophisticated hydrodynamic and sediment transport modelling. This modelling will simulate how the construction of new berths, breakwaters, and wharves will alter current patterns, tidal flows, and wave energy within Cockburn Sound. By predicting these physical changes, scientists can evaluate the potential for increased turbidity, changes in sedimentation rates, and the potential migration of contaminated sediment plumes. This data is vital for ensuring that the physical presence of the shipyard does not inadvertently degrade adjacent marine parks or seagrass meadows through altered water movement or light attenuation.

Terrestrial and geotechnical investigations will run in parallel, focusing on soil and groundwater characterisation across the landward portion of the precinct. Geotechnical boreholes, cone penetration testing (CPT), and seismic profiling will map the seabed stratigraphy and land-side load-bearing capacities. Historically, defence and shipbuilding sites have been associated with various contaminants, including firefighting foam residues (PFAS), solvent plumes, and asbestos-containing materials. These terrestrial studies must trace the migration pathways of groundwater from the industrial landwards zone toward the marine environment. Characterising the groundwater-surface water interface is highly complex, requiring continuous monitoring of water levels, salinity gradients, and contaminant concentrations to understand the dynamics of tidal pumping and its influence on contaminant flux into Cockburn Sound.

Australian context

The Henderson Defence Precinct project must navigate a complex, multi-tiered regulatory framework that serves as a benchmark for environmental compliance across Australia. At the federal level, any action that has, will have, or is likely to have a significant impact on matters of national environmental significance must be referred under the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act). The ecological sensitivity of Cockburn Sound, which supports diverse marine fauna and critical benthic habitats, means that Commonwealth oversight and approval will be required under the EPBC Act before development can proceed.

References and related sources

• Primary source: www.defence.gov.au

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This is an iEnvi Machete news summary. Prepared by iEnvi to summarise the source article for contaminated land, groundwater, remediation, approvals and site risk professionals.

Published: 17 Jun 2026

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