Living seawall trial Brightwater Lake

It is hoped the living seawall will create more habitat for marine creatures within the constructed waterbody and improve its biodiversity by encouraging more seaweed to grow, create more homes for sea life and draw more fish into the lake.

It could also have the added benefit of improving water quality, and is a first for the Sunshine Coast.

The 18 month research trial is a project being undertaken through the Sunshine Coast Council and University of the Sunshine Coast regional partnership agreement.

About the project

Living seawalls have been successfully used in multiple Sydney locations, Port Adelaide, Townsville, and Fremantle. As well as internationally in Wales, Gibraltar and Singapore.

The aim is to improve habitat for marine species in harbours, marinas, and on sea walls, with the aim of increasing biodiversity in and around these often-bare manmade structures.

The installation in Brightwater Lake is the first time these tiles have been used in a constructed, saline, waterbody.

With names such as 'swim through', 'crevices' and 'honeycomb' - each panel has been uniquely designed to mimic a variety of natural shoreline habitats, encourage seaweed to grow and serve as a refuge for marine creatures.

How living seawalls work

• Brightwater Lake links to the Mooloolah River and is one of the Sunshine Coast’s newer constructed waterbodies
• its perimeter is a smooth, featureless concrete wall which lacks any of the characteristics of a natural shoreline or waterway
• living seawalls address this by retrofitting the wall with panels that mimic microhabitats and create protective spaces for fish and other marine life
• council has been monitoring life in Brightwater Lake since 2021 using baited remote underwater video stations
• fish, including gobies and bream, are already present but the aim is to draw in a more diverse list of native species
• through this trial, 50 habitat panels will be installed at two sites in the lake which have slightly different conditions
• UniSC will monitor the changes in the species that live on the seawalls, like seagrass, algae and invertebrates and then the fish life that lives near the seawalls
• depending on the outcomes of the trial, it could be extended or replicated in other locations in the future
• installing living seawalls on existing infrastructure to improve biodiversity and habitat is called eco-engineering
• eco-engineering is when urban structures are designed for ecological co-benefits
• the research objective is to see if the installation of the living seawall in a constructed man-made lake, such as Brightwater Lake, will improve the variety and abundance of marine species
• this trial will give us scientific data on the benefits of eco-engineering techniques, like living seawalls, from a local perspective.

Why are we doing the trial in a constructed waterbody and not out in the ocean?

This is the first trial of these tiles in a constructed water body that isn’t directly connected to the ocean. We are interested to find out whether these tiles can be used in such an environment (low currents, not tidal, lower salinity). If they are successful, they could be used in other constructed waterbodies on the Sunshine Coast to provide habitat to marine creatures, improve biodiversity and overall ecosystem health.

Can this method be used in the ocean?

Yes, this can be used in the ocean as well. For information on ocean locations in Sydney and beyond, visit living seawalls.

Timeline

This is an 18 month trial - starting in June 2023.

Next steps

UniSC will attend at regular intervals to monitor the use of the tiles by marine plants and animals.

The outcomes of the trial will be shared with industry, government and community.

Learn more about living seawalls

Learn more about this innovative product from the Sydney Institute of Marine Science how it has successfully been used in other areas of Australia and internationally.