Program Overview
Birdon has delivered three major dredging campaigns at Garden Island, Sydney Harbour—home to Fleet Base East (FBE) and the Royal Australian Navy’s HMAS Kuttabul. These projects have restored critical berth pockets and navigation channels to design depths, ensuring operational readiness for current and future naval vessels.
This page features Project 2, the most recent campaign completed in January 2025, which involved the removal and treatment of contaminated sediments including asbestos and tributyltin (TBT). The project was delivered under contract EST03530 HMAS Kuttabul Dredging Works and represents Birdon’s continued excellence in Defence infrastructure maintenance.
Quick Facts
- Client
Department of Defence (via PDS Contractor)
- Location
Garden Island, Sydney Harbour
- Lifecycle Stage
Maintain
- Volume Dredged (Project 3)
~4,379 m³ + ~3,000 m³ over-dredge
- Contaminants
TBT, asbestos, heavy metals, PFAS
Objectives
- Restore berth pockets and channels to design depths
- Enable safe berthing and maintenance of naval vessels
- Remove and dispose of hazardous sediments in compliance with NSW EPA and Defence standards
Challenges
- Contaminated sediments
- Coordination with Defence operations and vessel movements
- Complex logistics for sediment treatment and disposal
- Strict environmental and safety compliance requirements
Birdon’s Approach
Birdon deployed a technically advanced and environmentally responsible methodology:
- BHD Sydney (spud-mounted backhoe dredge with 100t Liebherr 984 excavator)
- Split hopper barges (Pelican – 1,000 m³; Barge 139 – 500 m³)
- Wharf-based 30t long-reach excavators for sediment treatment
Contaminated Sediment Management:
- Sediment classified as Restricted Solid Waste (RSW) due to TBT and asbestos
- Developed a proprietary polymer additive to solidify saturated dredge spoil, making it “spadeable” for safe truck transport
Environmental & Quality Controls:
- Silt curtains, water quality monitoring and marine fauna spotters deployed
- Daily logs, waste tracking certificates, weighbridge dockets and toolbox meetings ensured compliance and transparency
Outcomes & Impact
The project restored six critical berths to design depths, supporting ongoing naval operations at Fleet Base East.
On-time delivery was achieved within the scheduled window from September 2024 to January 2025, with full adherence to NSW EPA and Defence protocols. The proprietary polymer treatment method proved more cost-effective and safer than traditional cement or dewatering approaches.
Capabilities in Action
- Deployment of specialist dredging equipment including backhoe dredge and split hopper barges
- Management and treatment of contaminated sediments
- Development and application of polymer-based solidification methods for safe transport
- Offshore disposal operations under Commonwealth Sea Dumping Permit with GPS-tracked precision
- Environmental and safety controls including silt curtains, water quality monitoring and marine fauna management
- Delivery in accordance with NSW EPA requirements and Defence protocols
- Certified operations aligned to ISO 9001, ISO 14001 and ISO 45001 standards
