Coastal defenses, like seawalls and bund walls, are required for the protection of urban and industrial development. They are often associated with negative ecological impacts however, these structures also represent an opportunity to achieve sustainability goals when combined with efforts to create new habitats.
GPC and CQUniversity are undertaking a project within the Port of Gladstone, which aims to investigate the viability of creating new intertidal sediment habitat adjacent to reclamation areas. This project and partnership is being driven via two co-funded PhD research scholarships.
The existing construction of reclamation areas in the port has shown increases in tidal flows adjacent to the seawall, with flow control structures required to prevent the erosion of potentially placed sediments. Numerical modelling has been used to find the most suitable structures, which highlights the use of regularly spaced perpendicular groynes to produce a sedimentation zone and prevent erosion of the placed sediment. This information was used to design the overall “Working with Nature” seawall concept and select the initial trial areas.
The initial stages of the study focused on mangroves, oyster reefs and seagrass meadows due to the following factors:
- Respective importance regarding ecosystem services,
- Local occurrence and abundance,
- Availability of findings from previous restoration attempts, and
- Knowledge of their preferred environmental conditions.
In considering which habitat is most suitable, there is an opportunity to assess the area holistically and optimize the ecosystem services for the proposed habitat. The focus of the second PhD scholarship is understanding the environmental economics associated with these ecosystem services. This research and their value provides essential information for the future incorporation of habitat enhancement into shoreline protection, whether required for industrial / urban development, or the resilience of existing coastlines due to climate change and rising sea levels.