Coastal Management
The City of Busselton has been successful in securing $3,532,500 grant funding in July 2022 from the Department of Industry, Science, Energy and Resources (Federal) – National Emergency Management Agencies (NEMA) – funding program Preparing Australian Communities Program (PACP).
This project is co-funded by the City of Busselton from its Coastal and Climate Adaptation Reserve resulting in a total project budget of $7,065,000 to be implemented over four budget years.
This project is currently in year two of four of its implementation.
This infrastructure project is anticipated to improve the resilience of the community to flood and tropical cyclone in the social, economic, natural, and built environments by mitigating the risk of coastal flooding associated with tropical cyclone storm surges through emergency planning, impact modelling, dune resilience works and construction of coastal flood mitigation structures in Busselton.
The project outcomes are as follows:
Emergency Response Plan
A multi-agency steering group was established for the Preparing Australian Communities Program (PACP) in August 2022.
The City has established Local Emergency Management Arrangements, delineating the responsibilities of various agencies in responding to emergencies within the region, encompassing a diverse array of hazards.
An anticipated outcome of the PACP project includes the updated mapping of the storm surge hazard for Busselton, scheduled for completion by mid-2024.
Wave buoys have been installed in Geographe Bay since 2022 to allow real-time monitoring of storm events. Tide gauges to measure storm surge in real-time are planned to be installed in Dunsborough and the Busselton Jetty in 2024.
Coastal Investigations (Flood Modelling)
The Coastal Investigations component of the project is progressing.
A targeted oceanographic monitoring program (water levels and waves) was completed in 2023, to better understand storm surge behavior in Geographe Bay, and provide a data set for validation of numerical models.
Coastal modelling works are being completed by an external consultant across five stages:
- Stage 1 - Tropical Cyclone Modelling
- Stage 2 - Dune Erosion Assessment
- Stage 3 - Coastal Inundation Modelling
- Stage 4 - Interaction of Coastal and Catchment Flooding
- Stage 5 - Mitigation of Coastal Inundation
Dune Resilience Works
Planning, design, and approvals have commenced for the dune resilience works.
Environmental surveys (vegetation mapping and fauna surveys) were undertaken by an external consultant in 2023. A Coastal Survey was also utilised to allow development of a coastal vegetation map of the dunes along Geographe Bay, to better understand resilience to storm surges, and plan mitigation works.
Vegetation surveys have been undertaken at two trial sites proposed for Dune Resilience Works (Stage 1) in Abbey and Broadwater.
Dune Resilience Stage 1 is scheduled to commence in May/ June 2024.
Stage 2 works are planned for 2025, with the location, design and scale to be determined by coastal modelling and lessons learnt from Stage 1 works.
Further information on Stage 1 can be found below.
Coastal Flood Mitigation
The design of Coastal Flood Mitigation works is scheduled to commence in July 2024. Design and construction of coastal flood mitigation works will be based on recommendations of the coastal investigations (flood modelling). These works may include raising drain embankments, stormwater non-return valves and coastal levees (Stage 2 works) to mitigate risk of coastal flooding in low lying areas.
More information on this stage will follow.
Stage 1 Dune Resilience Works
The proposed Stage 1 Coastal Dune Resilience Works will commence in May/June 2024 in West Abbey and Broadwater.
West Abbey Coastal Dune Resilience
The work scope is to rebuild eroded coastal dunes west of the boat ramp that collapsed during storms in May 2020, that will provide a natural buffer to coastal inundation. The Dune Resilience Works will be undertaken over a narrow 0.4ha area west of the Abbey Boat ramp.
The works at West Abbey will include:
- Communication with residents regarding planned works
- Demarcation of the work site to protect adjacent coastal vegetation and for public safety
- Carting and placement of a mix of imported and local sand as a series of dune ridges and swales
- Planting coastal dune seedlings
- Installation of beach access matting over the dune whilst the planting gets established
Broadwater Coastal Dune Resilience
Constructing new coastal dune ridges across a potential flood pathway to provide a natural buffer to coastal inundation. The Dune Resilience Works will be undertaken over a 0.96ha area West of Dolphin Road boat ramp. Dune resilience works will be along 200m of the degraded dunes between the beach and the Peppermint Woodland in the coastal reserve.
Works are planned to commence in May/ June 2024 to take the opportunity of early winter rains and to increase the survival rate of dune seedlings.
Beach sand for dune rebuilding will be imported to the dunes or relocated from adjacent beaches where ongoing accretion occurs. Selective planting of native species will be undertaken to both increase the resilience of the dune surface to erosion, and to restore or enhance the ecological function of the coastal dune habitat.
Additional Information
Coastal Inundation Sketches 1 - Dune Resilience
Coastal Inundation Sketches 2 - Dune Resilience