Coastal Management
The City has been successful in securing a number of grants to undertake a range of coastal management activities in response to the ongoing risks presented by coastal erosion.
As part of the monitoring work being undertaken, the City has installed buoys to monitor marine tides, mapped coastline movements and surveyed beach profiles at numerous locations along the coast. Multiple projects are planned, with the goal of implementing engineering solutions to rehabilitate a number of dunes, coupled with the replacement or upgrade of other coastal infrastructure to protect against further erosion.
The City has been successful in securing two different Federal grants from the Department of Industry, Science, Energy and Resources - CERMP (Coastal and Estuarine Risk Mitigation Program) and PACP (Preparing Australian Communities Program).
Coastal and Estuarine Risk Mitigation Program (CERMP)
The CERMP funding has been received for two projects:-
- West Busselton Coastal Stabilisation
The aim of the infrastructure project is to provide longer term coastal protection to mitigate the impacts of coastal hazards along the coast between King Street and Gale Street in Busselton. The construction will include a series of new Geotextile Sand Container (GSC) groynes and sand nourishment.
The low-profile groynes will provide stabilisation to the West Busselton coastline and limit the erosion of the established vegetation and potential loss of the coastal road. This technique is used widely by the City of Busselton along the Geographe Bay foreshore.
This project is currently in the design phase, and will be going to procurement later this year, with works scheduled to be undertaken in February – April 2025.
- Vincent Street Seawall Refurbishment
The aim of this project is to refurbish the existing 400m seawall structure at Vincent Street (just east of Mentor Place heading east towards Lecaille Court) in Dunsborough to ensure it continues to function as a coastal protection structure. The works will also improve the visual amenity of the structure.
This project will increase protection to vulnerable assets by helping to stabilise a rapidly eroding section of the coast. The assets to be protected include the coastal dual use path providing universal access along the coast, established woodland, and public foreshore infrastructure.
This project is currently in the concept design phase, with works scheduled to be undertaken in the 2025/2026 financial year.
Preparing Australian Communities Program (PACP)
The City of Busselton was also 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 funding was secured for the Geographe Bay Coastal Mitigation Works Project, which 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 three 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 2024, to better understand storm surge behavior in Geographe Bay, and provide a data set for validation of numerical models.
Coastal modelling works have been 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 are well underwayfor 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 was completed in West Abbey and Broadwater in July 2024.
Stage 2 works are planned for November 2024 – April 2025, with the location of the works 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 commenced in July 2024. Design and construction of coastal flood mitigation works will be based on recommendations of the coastal investigations (flood modelling). These works 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 Stage 2 is shown below.
Stage 1 Dune Resilience Works
The proposed Stage 1 Coastal Dune Resilience works were undertaken in May/June 2024 in West Abbey and Broadwater. East Abbey Groyne Repair works are scheduled for later in 2024.
West Abbey Coastal Dune Resilience
The work scope was 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 were undertaken over a narrow 0.4ha area west of the Abbey Boat ramp.
The works at West Abbey included:
- 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
These works include the construction of new coastal dune ridges across a potential flood pathway to provide a natural buffer to coastal inundation. The Dune Resilience Works were undertaken over a 0.96ha area West of Dolphin Road boat ramp.
Works were completed 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 was imported to the dunes and 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.
East Abbey Groyne Repair Works
This groyne is a critical piece of coastal protection structure, but it is now damaged and in need of replacement. The City will be removing the timber groyne and replacing it with a new geotextile sand container groyne in the same location to the east of Abbey Boat Ramp. This will be a ‘low profile’ groyne to allow sand to naturally bypass and to ensure there is a minimal impact to the beach environment and amenity. This will be similar to the geotextile sand container groynes that have been constructed west of the boat ramp in recent years.
It is anticipated that these works will commence in November/ December 2024 and be completed within 4-8 weeks, subject to weather conditions.
Additional Information
Coastal Inundation Sketches 1 - Dune Resilience
Coastal Inundation Sketches 2 - Dune Resilience
Stage 2 Dune Resilience Works and Coastal Flood Protection Levees
The below works are schedule to commence in November 2024 and be completed by April 2025, noting that some of the work will require agency approvals. If the approvals are not received in time some components of the works might not be completed.
1. East Busselton Coastal Paths and Dunes
The scope of works includes the following:-
- Dune Resilience Works (Ford Rd to Freycinet Dr) – Construction of stabilised coastal dunes in the foreshore reserve.
- Coastal Path Refurbishment – Levee (Wakeford St to Morgan St) – Refurbishment of low-lying sections of the coastal path to improve capacity to mitigate coastal flooding and widening to improve amenity (multi-purpose structure).
Please refer to Annexure A – for a copy of the Drawings of the proposed works.
2. West Busselton (Vasse Drain) Coastal Path and Dunes
The scope of works includes the following:-
- Dune Resilience Works (Margaret St) – Construction of stabilised coastal dunes in the foreshore reserve.
- Coastal Path Refurbishment – Levee (Vasse Drain) – refurbishment of the coastal path along the eastern side of the Vasse Drain Diversion to improve capacity to mitigate coastal flooding and widening to improve amenity (multi-purpose structure).
Please refer to Annexure B – for a copy of the Drawings of the proposed works.
3. West Busselton (Dolphin Road) Coastal Path, Dunes and Drainage Outlet
The scope of works includes the following:-
- Dune Resilience Works (Dolphin Rd) – Construction of stabilised coastal dunes in the foreshore reserve.
- Coastal Path Refurbishment – Levee (Dolphin Rd and Craig St) – refurbishment of the coastal path along the eastern side of the Vasse Drain Diversion to improve capacity to mitigate coastal flooding and widening to improve amenity (multi-purpose structure). This includes a vehicle cross-over at the boat ramp approach.
- Drain Outlet (Silverglenn Ave): Extension of stormwater outlet with non-return valve, headwall and levee bank.
Please refer to Annexure C – for a copy of the Drawings of the proposed works.