Offshore Artificial Reefs - Terrigal and Forster

Overview

Design, fabricate and install 4 x Offshore Artificial Reefs along NSW coast: Terrigal and Forster. A project delivered with SMC environmental subsidiary - SeaO2.

Principal

Department of Primary Industry NSW

1. Our Role

Deployment of artificial reefs in State offshore coastal waters is consistent with objectives of the Fisheries Management Act 1994 (NSW) by conserving, developing, and sharing fisheries resources of the State for the benefit of present and future generations and promoting quality recreational fishing opportunities.
The reefs are comprised of two steel towers each weighing approximately 50 tonnes with footprints of 16 x 16 metres and standing 12 metres high.
The reef key objectives to increase productivity of marine life and to attract key fish species for recreational fishers to target.
We have used innovative, and state of the art reef designs to deflect currents to create eddies and upwellings to provide intricate habitats for a variety of fish species and maximise biological outcomes.

Design coordination from world leader Naval Architect, Ocean Engineer, and Marine scientist
International procurement and logistics
Sydney assembly and launch, using one of our large capacity barges, Kochi (210T lift capacity)
Innovative Tow and Sink deployment

2. Issues and Resolution

Stability: Reefs had to be self-weighted and physically stable to withstand one-in-100-year storm event, effecting sliding and overturning. This had led us to perform refined work on a Low drag design and a low Centre of gravity.
Installation and deployment: We developed a safe and accurate deployment methodology to sink those 50t reefs offshore in 40-45m depth of water.
Maximising biological outcome: The Reefs are fitted with various complex features to maximise biological outcomes and support an entire ecosystem - from biofouling, to benthos community, to pelagic species.
Re purposing of new material offcuts: 24 tons of new steel pile offcuts from the New Sydney Fish Market structural basement steel piles were reused in the Offshore Artificial Reefs, providing additional fish habitat and ensuring that the Reefs are stable during large storms.