RAAF Base Williamtown

Latest updates

Important information for communities around RAAF Base Williamtown.

2021-2023 Ongoing Monitoring Report with Appendix A-F – July 2024 (PDF, 37.77 MB)

2021-2023 Ongoing Monitoring Report Appendix G – July 2024 (PDF, 64.85 MB)

2021-2023 Ongoing Monitoring Report Factsheet – July 2024 (PDF, 1.77 MB)

Investigations and findings

In October 2018, Defence completed investigations into per- and poly-fluoroalkyl substances (PFAS) contamination on and around RAAF Base Williamtown. PFAS contamination from RAAF Base Williamtown is a significant issue for the local community. Defence is working with the New South Wales (NSW) Government to manage, remediate and monitor PFAS contamination in this area.

The investigations found that PFAS is mostly concentrated in areas where firefighting foams were previously used, stored or disposed. These are called source areas. The PFAS in these locations can be found in soil and in water flowing through the source areas. PFAS moves in surface water flowing through drains and creeks or groundwater that flows underground through soil and rock.

Eight source areas were found on the base where PFAS concentrations required further study or action:

• former and current fire station – including the fire training pad
• Lake Cochran
• sewage Treatment Plant and associated water ponds
• the former fire training area
• DEMS landfill
• trade waste treatment plant
• north east landfill - no longer a significant contributor of PFAS
• current fire station and fire training pad – mostly surface water to southern moors drain.

Human Health Risk Assessment

As part of the investigations, Defence conducted a Human Health Risk Assessment. This assessment measured the PFAS exposure risks to people living, working and undertaking recreational activities within the management area. Findings from the risk assessment found there were some activities that have a higher PFAS exposure risk. Based on these findings, the NSW Protection Authority (EPA) released precautionary advice for residents within the Williamtown management area, to minimise their exposure to PFAS.

More details on Defence’s risk assessments can be found in the Human Health Risk Assessment factsheet and the Ecological Risk Assessment factsheet.

Remediation and management

The aim of remediation is to minimise PFAS leaving the base, by focusing on the remediation and management of the source areas. Over time this will contribute to the reduction of PFAS in the management area. Defence has a PFAS Management Area Plan setting out the proposed remedial works and other management actions to manage potential risks presented by PFAS.

Soil remediation

Soil remediation at RAAF Base Williamtown has focused on the major source areas where PFAS levels are concentrated. Defence removed more than 14,000 tonnes of contaminated soil from source areas on base, including the fire station area and the former fire training area. Soil that met the NSW EPA standards for disposal was transported to a special purpose landfill, and 1,500 tonnes of soil was transported to RAAF Base Edinburgh and used in a soil washing trial.

Groundwater remediation

RAAF Base Williamtown has been subject to extensive groundwater remediation since 2016. There are currently 2 groundwater treatment plants operating on the base. More than 1 million litres of groundwater are pumped daily from under the former firefighting training area. The treatment involves removing PFAS from the water and then irrigating it back onto the base using sprinklers.

Groundwater is also taken from the southern base boundary to catch PFAS from Lake Cochran, before it leaves the base. About half a million litres per day are extracted and treated before being irrigated back onto the base.

Surface water remediation

Defence’s investigations found that surface water is one of the major pathways that PFAS leaves RAAF Williamtown and enters the management area.

At Moors Drain, surface water is collected and treated to remove PFAS and then returned to the drain. Defence is also testing passive PFAS removal systems for stormwater drains. These are engineered structures that remove PFAS as it flows naturally through the drain.

Groundwater Strategy Review

In October 2022, Defence completed a strategy review to assess the effectiveness of remediation actions used at RAAF Base Williamtown. The review was completed by a panel of independent local and international experts.

The review recommended more groundwater extractions off the base near Cabbage Tree Road and on the southern base boundary near the former fire fighter training area. The extractions will decrease the amount of PFAS leaving the base and greatly reduce the PFAS flowing to Fullerton Cove.

Additional surface water treatment was also recommended on Moors Drain, to make the current system more effective. The recommendations of the strategy review will form the basis of the revised PFAS Management Area Plan to be issued in 2023. Defence will publish further information on these recommendations as they are implemented. The strategy review is available to download.

Remediation trials

The Groundwater Strategy Review also recommended more remediation trials. The trials would be used to improve the long term management of PFAS impacted ground and surface water at the base.

One of the recommended trials is a carbon barrier, where a trench is dug and activated carbon is placed across it. As water flows through the trench, the carbon catches the PFAS. Other remedial trials will also be considered as new technologies develop and evolve.

Alternative drinking water supply

Defence is providing water assistance to eligible properties within the Williamtown management area. For further information, please contact the Williamtown Information Line during business hours on 1800 011 443 (free-call) or williamtown.defence@aecom.com.

Ongoing monitoring

Monitoring of PFAS continues through sampling of surface water, groundwater, sediment and biota. Monitoring helps Defence understand if PFAS contamination is changing over time.

Monitoring results to date has shown that PFAS concentrations in and around the source areas has reduced as a result of remediation. However, the concentrations of PFAS in the management area remain broadly the same. It has taken several decades for PFAS to spread into the management area through groundwater and surface water flows. The remedial works are expected to reduce PFAS from leaving the base, and over time this will contribute to the reduction of PFAS in the management area.

Results are published in an Ongoing Monitoring Interpretive Report and factsheet. Defence will inform the community if changes to the management approach are required.

Recent reports and factsheets

Detailed reports from the PFAS investigation and management program are available for download. Appendices to these reports can be found in the document archive. To discuss these reports, contact pfas.enquiry@defence.gov.au.

• Revised PFAS Management Area Plan – December 2023 (PDF, 2.9 MB)
• Updated Ongoing Monitoring Plan – December 2023 (PDF, 1.88 MB)
• Revised PFAS Management Area Plan and Updated Ongoing Monitoring Plan Factsheet – December 2023 (PDF, 531.11 KB)
• Community Information Session - Oct 2022 presentation (PDF 4 MB)
• Community Information Session - Oct 2022 factsheet (PDF 920 KB)
• Ongoing Monitoring and Remediation Update - Aug 2021 factsheet (PDF 1.3 MB)
• 2021 Ongoing Monitoring Interpretive - Oct 2022 report (PDF 59 MB)
• PFAS Management Area Plan - July 2019 factsheet (PDF 1.5 MB)
• PFAS Management Area Plan - May 2019 report (PDF 19.9 MB)
• Groundwater Strategy Review Remedial Options - Sep 2022 report (PDF 57 MB)
• Groundwater Strategy Review Numerical Groundwater Model Update - Sep 2022 report (PDF 27 MB)
• Addendum to Stage 2C Environmental Investigation: Human Health Risk Assessment - July 2016 report (PDF 289 KB)
• Human Health Risk Assessment - August 2016 factsheet (PDF 670 KB)
• Off-site Human Health Risk Assessment: Sensitivity Assessment Findings - April 2017 factsheet (PDF 10.3 MB)
• Off-Site Human Health Risk Assessment: Volume 2 - Dec 2017 report (PDF 67 MB)
• Ecological Risk Assessment - Oct 2018 factsheet (PDF 1.2 MB)
• Ecological Risk Assessment - Sep 2018 report (PDF 69.3 MB)
• Environmental Site Assessment - Aug 2016 factsheet (PDF 1.04 MB)
• Environmental Site Assessment: Executive Summary - June 2016 report (PDF 185 KB)
• Water Reticulation Project and Payment of Hunter Water's Service Fee and Usage Charges - March 2018 factsheet (PDF 87 KB)

Water Treatment Plant reports

Reports from the management of Water Treatment Plants.

Water Treatment Plant Sampling Results RAAF Base Williamtown Moors Drain (formerly ECT2 Interim) (PDF, 2.01 MB)

Water Treatment Plant Sampling Results RAAF Base Williamtown Southern Area (PDF, 1.89 MB)

Water Treatment Plant Sampling Results RAAF Base Williamtown Fire Training Area (PDF, 1.63 MB)

Water Treatment Plant Sampling Results RAAF Base Williamtown Lake Cochran DECOMMISSIONED (PDF, 2.52 MB)

Document archive

The RAAF Base Williamtown document archive contains information about the management of PFAS, including older community presentations, investigation reports, risk assessments and factsheets.

Some archived documents have been superseded by recent reports and factsheets.

Documents Archive - Williamtown (PDF, 320.73 KB)

Last review: 14 December 2023