Environmentally Friendly Moorings
Boating in Sydney Harbour
Boating on Sydney Harbour is an iconic and socio-economically significant part of the harbour’s identity. To support this, the harbour hosts more than 5,000 boat moorings located in shallow bays around the estuary. Traditionally, these moorings consist of a heavy chain and concrete block that allow safe anchorage for vessels. However, with the movement of tides and winds, the heavy chains swing and scour the seafloor—causing long-term damage to seagrass meadows and the important ecosystems they support.
Importance of Seagrass
Sydney Harbour is home to Posidonia australis, an endangered species of seagrass. This slow-growing plant is the largest seagrass in Australia, where it forms highly productive meadows that provide critical habitat and refuge for many juvenile fish, improve water quality, stabilise sediments, and act as a significant carbon sink by capturing and storing carbon dioxide, helping to mitigate climate change.
The Solution: Environmentally Friendly Moorings
To help the boating community and Posidonia australis thrive side by side, researchers from Project Restore at the Sydney Institute of Marine Science (SIMS) have installed 10 Environmentally Friendly Moorings (EFMs) at Balmoral. Unlike traditional moorings that use heavy chains, EFMs are neutrally buoyant and secured with a low-impact screw piling system, leaving a much smaller footprint on the seafloor. This design prevents chain scouring and protects vital seagrass habitat without compromising reliability.
With many manufacturers now offering these systems, EFM technologies have been successfully trialled and implemented both locally and internationally in extreme weather and tidal conditions. They are used around the world for individual swing moorings, as well as large-scale infrastructure such as marinas and offshore solar farms. For this Project Restore installation, Seaflex systems will be installed based on vessel size, environmental conditions, and technical recommendations from the supplier.
Our Restoration Work
The team has now begun the seagrass restoration element of this project by planting 800 Posidonia shoots beneath the EFM’s. Yesterday, we planted 800 endangered Posidonia shoots beneath our recently installed Environmentally Friendly Moorings (EFMs) at Balmoral Beach.
This milestone represents the culmination of three years of collaboration with the boating community, mooring contractors, and scientists.
We look forward to continuing to monitor the site and to sharing the positive impact this innovative technology can have on the local ecology — particularly on the recovery and protection of seagrass meadows.
Our Stakeholders & Collaborators
- Treharne Moorings
- Balmoral Boatshed
- SMADS
- Seaflex
Please reach out to Tom Burd (tom.burd@sims.org.au) at the Sydney Institute of Marine Science to learn more about the technology and the research we are undertaking in Sydney Harbour.
In the Media
Explore the links below to learn more about the different restoration methods that make up Project Restore.
