Why are coastal risk management options for Port Beach in North Fremantle being investigated?
During 2016 and 2017 the City of Fremantle in partnership with the Town of Mosman Park and Department of Planning, Lands and Heritage completed a Coastal Hazard Risk Management and Adaptation Planning (CHRMAP) process, to assess the vulnerability of the coastline and adjacent assets along Port, Leighton and Mosman beaches.
The CHRMAP included a review of potential coastal risk management options to improve the consequences or reduce the likelihood of coastal hazard impacts of erosion. The development of the plan was co-funded by the State Government and adopted by both the City of Fremantle and Town on Mosman Park councils in 2017.
The CHRMAP identified that the Port Beach area including Sandtrax Beach, is vulnerable to immediate and future coastal change and the development of coastal risk management options should be completed as a priority. To implement key recommendations of the CHRMAP, the City of Fremantle, in partnership with Fremantle Ports, was successful in acquiring a Department of Transport’s Coastal Adaptation and Protection grant to investigate a range of coastal risk management options and provide the community and key stakeholders with a defined concept plan to address the coastal hazard impacts of erosion. A Project Working Team (with project partners, the Department of Transport and Fremantle Ports) has been established to oversee this current process.
What is causing the coastal erosion at Port Beach?
The shape of the coastline is continuously changing in response to the forces acting on it: wind, currents, waves and the level of water. Furthermore, Port Beach is essentially an artificial beach that was shaped by the early construction work associated with the Fremantle Harbour and Fremantle Port.
These early works placed large volumes of sand and rubble on the beach and in the nearshore area. Over time the sand placed on Port Beach has been lost due to natural coastal processes as the sediment has been transported to the north and the beach realigns to a more natural alignment.
What is coastal risk management planning and what options will be considered for Port Beach?
Coastal risk management planning is about being ready to manage the risks to the assets and values within the Port Beach locality associated with the impacts of changes to our coast line, by planning for the most appropriate decisions and options to implement over time.
received from the community and key stakeholders will help to shape the assessment
of coastal risk management options. Possible
options could include:
- beach and dune nourishment (bringing in sand to place on the beach and dune),
- relocation of coastal infrastructure, e.g. car park and changing rooms
- construction of seawall,
- construction of groynes,
- a combination of these options or other options as required.
How will the coastal risk management options better manage the erosion at Port Beach?
The risk management option/s chosen will determine how Port Beach will adapt to the effects and mitigate areas affected by coastal erosion in the future.
For instance, a beach and dune nourishment option may help to protect coastal assets from erosion by increasing the buffer (distance and volume of sand) between the ocean and the assets. Alternatively, a seawall could protect coastal assets against erosion by providing a robust defence against the action of waves on the coastline.
How will the coastal risk management options be evaluated?
The evaluation of coastal risk management options will be completed using a multi-criteria analysis. This analysis will rank the options based on the relative benefits of each option across a range of criteria, which will be based on community feedback. These include social value, environmental impacts, economic impacts and construction and operation/maintenance costs.
As part of selecting a preferred coastal risk management option, there will be consideration of trade-offs between each of the potential options available for Port Beach.
An example of this could include beach and dune nourishment which may maintain beach amenity and access, however would come with significantly higher and ongoing maintenance costs relative to other available options. Alternatively, a seawall may potentially result in the loss of beach from time to time and would be relatively expensive to construct, however would be relatively low in cost to maintain over time.
When will the chosen option be implemented?
A concept plan will be developed through the process and presented to Council in mid 2019.
Further updates will be provided at this point, but the next phase is expected to be detailed design of the chosen concept. Additional community consultation may also occur in this phase.
The final phase is implementation of the design. This may need to be delivered over several years depending on the concept selected.
An ongoing monitoring and maintenance program will also be developed and implemented.
Each phase is dependent on annual funding and budget allocation.
Will the coastal risk management options impact facilities and amenity at Port Beach?
In regards to facilities and amenity such as parking, change-rooms, Surf Life Saving Facility and commercial food and beverage outlets - the community and stakeholder engagement process will help to establish the community values attributed to these assets.
Assets that are deemed to be very important, will be given greater consideration for accommodation within the coastal risk management options. It is possible that some assets will need to be relocated locally, to achieve better outcomes.
How much will it cost to implement the coastal risk management options and how long will it take?
The cost of both construction and ongoing operation/ maintenance and the timeframe for implementation will depend on the selected risk management option/s. Opportunities to seek funding to assist with the construction will also be investigated. Consideration will be given to staging of the selected risk management option/s wherever possible.
How can I provide my feedback on the coastal risk management options?
Phase one engagement is now open on My Say Freo. Everyone who provides contact details will be kept up-to-date as the project progresses.
What is being done about the rocks on the beach and other site contamination?
Port Beach is an artificially created beach built on a foundation of dredge material including sand, limestone rock and coral fragments that has historically been dumped there through the creation of the Port in the late 1800s. Limestone rock and coral fragments can be seen throughout the beach profile.
From time to time conditions will be such that the lighter sand grains interspersed with the material will wash away and the limestone rock and coral fragments will be exposed. At other times the sand will come back and cover it up again. There are signs in place warning beach users about the possibility of exposed rocks and rubble on the beach during these erosion periods.
In recent decades a number of attempts have been made to address the rocks on Port Beach, including using excavators and bobcats to remove them, but all of these attempts have only been successful in removing the rocks from the surface level. As the beach has been largely formed by dredged sand and rocks, it is expected rock fragments will continue to be present on Port Beach from time to time.
Will the coastal risk management options impact access to Port Beach Road, North Mole and the Inner Harbour?
Continued access to Port Beach Road, North Mole and the Inner Harbour will be a key consideration when evaluating coastal risk management options to ensure there is no impact.
Will the community continue to have access to Port Beach and the water off Port Beach?
Community access to Port Beach and the water off Port Beach will continue to be provided, however the location of and form of this access will depend on feedback received from the community and stakeholders and the risk management option/s that are selected.
Why are coastal risk management options at Port Beach only being considered and not Leighton or Mosman Beaches?
Through the CHRMAP process, Port Beach was identified as being highly vulnerable to coastal erosion. Both Leighton and Mosman Beaches do not have the same level of vulnerability from coastal hazard impacts and can be monitored and maintained through dune stabilisation over the short to medium term.
The coastal risk management options that are developed for Port Beach will be designed to have minimal negative impact on Leighton or Mosman Beaches or the surrounding marine area.