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Reviewing jetty designs

Published 8 September 2023 Reviewing jetty design to better protect seagrass.
content image Jetties and pontoons can pose a threat to the health of seagrass beds.


Why is this project important?

Jetties and pontoons provide access to the benefits of the marine estate, however poor design can pose a threat to the health of seagrass beds as they reduce the amount of available sunlight.

Seagrass beds are a key estuarine habitat. They provide food and shelter for many marine animals, including commercially and recreationally important fish species. Seagrasses are marine plants and require sunlight to live and grow.

Seagrass meadows also oxygenate water, stabilise sand, improve water quality by recycling nutrients and act as a highly efficient carbon sink.

This project is researching the design features of jetties to determine what leads to the loss of seagrass and develop jetty design guidelines to help reduce this loss.

We are surveying seagrass under and adjacent to jetties across many NSW estuaries to determine what design features lead to seagrass loss. Design features being assessed include the height, width, orientation and construction material of the jetty.

Results from this project will help inform design guidelines to better protect seagrass.

You can learn more about the importance of seagrass in NSW on the DPI Fisheries webpage.

What have we achieved so far?

  • Over 300 jetties have been surveyed in Port Hacking for seagrass occurrence.
  • 90 diving surveys have been conducted in Port Hacking to measure seagrass biomass under and adjacent to jetties.

We will be using this information to establish the best practice with the construction of jetties across NSW.


Estuaries in the Greater Sydney region

Local government areas - Statewide

Lead agency

Department of Primary Industries – Fisheries

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