Background to coastal erosion at Port Beach
- retreat and protect –relocation of coastal infrastructure at risk, e.g. car park and changing rooms, and construction of a seawall adjacent to Port Beach Road extending the useable beach area.
- protect - sand nourishment (bringing in sand to place on the beach and dune), extending the useable beach area,
- protect - construction of seawall in front of existing coastal infrastructure,
protect - construction of groynes or headlands in front of existing coastal infrastructure.
Why are coastal risk management options for Port Beach in North Fremantle being implemented?
During 2016 and 2017 the City of Fremantle in partnership with the Town of Mosman Park and Department of Planning, Lands and Heritage, with support from Fremantle Ports, Department of Transport, Department of Water and Environmental Regulation, Town of Cottesloe, and Perth NRM Coastal and Marine Program, 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 Western Australian Planning Commission 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 recommended coastal protection via seawalls and /or sand nourishment be further investigated 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 Coastal Adaptation and Protection grant to investigate the technical feasibility of coastal protection options and provide the community and key stakeholders with a defined concept plan to address the immediate coastal hazard impacts of erosion. A Project Working Team led by City of Fremantle (with project partners, the Department of Transport and Fremantle Ports) has been established to oversee this process.
What is causing 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. Erosion of the shoreline has occurred at varying rates since the 1990s.
Port Beach is essentially an artificial shoreline environment, with a significant history of man made changes including early construction works 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. Numerous construction activities have also occurred since the initial construction of the harbour including placement of significant volumes of dredged material either directly along the shoreline or immediately adjacent to Port Beach in the 1920’s, 1950’s and 1960’s
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?
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 coastline, by planning for the most appropriate decisions and options to implement over time.
What coastal risk management option has been selected for Port Beach?
In March 2019, the City asked key stakeholders and the community for their input to help shape the assessment of coastal protection options and inform a concept plan to address the immediate coastal erosion risk in the Port Beach locality. A combination of possible protection options were
Each of these options were assessed via a multi-criteria analysis (MCA), which also included technical, social, environmental and economic criteria. Informed through community consultation, social criteria included provision of a beach and active recreation opportunities, coastal amenity, car park amenity, retention of the surf club annexe and change rooms, safety for beach users, along with entertainment and socialising opportunities.
Through the MCA, sand nourishment via dredging was selected as the preferred interim adaptation option – i.e. to provide protection to infrastructure over an approximately 10 year time frame.
Regarding management of coastal risks in the long term, in December 2019 Fremantle Council adopted a policy position of position of managed retreat for Port Beach, to be implemented over an extended timeframe. This involves considering the impacts on adjacent beaches and existing infrastructure and advocating for appropriate planning mechanisms to support the strategy, with implementation over an extended time frame to ensure that social, environmental and economic costs are minimised.
Sand nourishment via dredge - Project Background
What is involved in implementing sand nourishment at Port Beach?
In 2020 and in conjunction with the Department of Transport and Fremantle Ports, the City undertook further detailed investigations and detailed design of sand nourishment via dredging. In August 2020, the State government announced as part of the $5.5billion WA Recovery Plan, it would allocate $3.25million to the City of Fremantle for a Port Beach large scale sand nourishment project to provide up to 10 years of protection.
The Project is planned to be delivered by City of Fremantle in two phases:
Phase 1 - Quarter 3 2021 - To prepare Port Beach for the sand nourishment program, the City will engage a contractor to undertake screening of sand within Sandtrax Beach and the southern 200m of Port Beach, south of Tydeman Road, to remove small rocks and excavate and remove large remnant rock from the defunct seawall.
Phase 2 - Quarter 2 2022 - To supply suitable sand for beach nourishment at Port Beach, 150,000m3of sand will be dredged from the Fremantle Ports Deep Water Channel and placed onto Port Beach. The works will involve marine based machinery transporting the dredged sand from the Fremantle Ports Deep Water Channel, with land-based machinery working on the beach to manage receival of the sand and construction of the beach profile
How will sand nourishment better manage erosion at Port Beach?
The Sand Nourishment via Dredging works will provide a buffer to protect landward assets against the effects of coastal erosion whilst also providing public amenity.
The design of the sand nourishment has been developed to provide a wide enough beach so that, with the anticipated movement of the placed sand, a sufficient buffer against cross shore erosion due to severe storms is maintained.
Presently, sand at Port Beach is being transported to the north, as the beach realigns to a more natural alignment. With this in mind, some of the placed sand is expected to migrate northwards over time. A shoreline monitoring program will be implemented to track the movement of the placed sand. If significant movement of the placed sand occurs, additional maintenance and/or nourishment works may be required.
When will the dredging and sand nourishment at Port Beach commence and how long will it take?
Phase 1 site works are scheduled to commence in late August / early September 2021 and are anticipated to take approximately 4 weeks to complete.
Environmental and other necessary approvals for Phase 2 are currently being worked through and are anticipated to be in place in late 2021.
Phase 2 – once approvals are in place, dredging and sand nourishment is anticipated to commence in the second quarter of 2022 and will take approximately 12 weeks to complete.
How much will it cost to implement the sand nourishment via dredge project?
A grant funding of $3.25 million has been allocated to the sand nourishment via dredge project, by the State Government, through the WA Recovery Plan.
Why is the City choosing sand nourishment via dredge as an option for managing coastal erosion in the short term, when the City is proposing a managed retreat strategy in the long term for Port Beach?
Sand nourishment via dredging has been selected over other potential protection options based on the outcomes of a multicriteria analysis through which criteria of technical, social, environmental and economic criteria were considered.
Managed retreat is Fremantle Council’s adopted long-term strategy for dealing with coastal erosion at Port Beach, with the ultimate aim of removing coastal assets from the erosion risk zone.
The sand nourishment adaptation option will address the current extreme erosion risk level while allowing time for a longer-term planning process to enable the implementation of a managed retreat strategy, that includes the establishment of a broader foreshore reserve to retain a beach and amenities for the community.
This will require a firm commitment from the WA Planning Commission and other state government agencies to start work as soon as possible on the planning changes required to establish the necessary coastal reserves.
The aim is to secure the reservation of an expanded foreshore reserve to accommodate managed retreat requirements and allow the transition out of the sand nourishment regime by 2030..
Why is the City dredging sand rather than bringing it in by truck?
Sand nourishment via trucking was considered as part of the MCA. There are two primary disadvantages of trucked sand when compared to using dredged sand.
The construction costs associated with the haulage of the large quantity of sand required, are significantly higher than sand acquired via dredging. Additionally, the trucking option results in significantly larger construction footprint and additional impacts to public use.
Will the community continue to have access to Port Beach and the water off Port Beach during the project?
Community access to Port Beach and the water near Port Beach will continue to be provided throughout the project as much as possible, however public safety is paramount and at times there will be sections of car parking and the beach, including the near shore area, temporarily closed whilst project works are undertaken.
Will the project impact facilities and amenity at Port Beach?
Continued access to facilities and amenity such as parking, change rooms, Surf Life Saving Facility and commercial food and beverage outlets will be a key consideration when planning the program of works for both phase 1 and phase 2 of the project, to minimise disruption to the community and visitors to Port Beach.
How will the project affect pedestrian and cycling and traffic movement at Port Beach?
There will be an increase in trucks moving through the immediate area as equipment is moved to and from site. A traffic management plan will be in place to manage any disruptions to cyclists, pedestrians and road users.
How will the project manage noise?
Project works will occur between 7am-7pm Monday to Saturday for Phase 1 of the project and Monday to Sunday for Phase 2 of the project.
For work outside of these hours, or on a Sunday or Public Holiday, a Noise Management Plan will be submitted to the City’s environmental health services team.
How will the project manage dust?
To reduce air blown sand and dust from the project, the Contractors will have a Dust Management Plan in place, which is compliant with state government guidelines.
What will the beach look like when the Project is completed?
At the completion of Phase 1, the beach will largely look as it currently does, with the remnant seawall removed and rock fragments through the beach area removed.
At the completion of Phase 2, the Sand Nourishment via Dredge works, the beach will be significantly wider than it is today. The Sand Nourishment via Dredge works also includes dune re-establishment and stabilisation, including coir matting, revegetation and dune fencing.
Sand nourishment via dredge project - Phase 1
What does the phase one program of works involve at Port Beach?
Phase one involves sand screening for small rocks within Sandtrax Beach and the southern 200m of Port Beach, south of Tydeman Road and removal of a remnant seawall.
The works will involve earthworks machinery and a sand screening plant working on the beach and shifting material to stockpiles located in closed areas of the carpark. There will also be trucks entering and leaving the site from time to time.
How long will it take to complete the phase one program of works at Port Beach?
The works are anticipated to commence from early October 2021, taking approximately 4 -8 weeks to complete.
Will people still be able to access the beach and the water?
The program of works will commence at Sandtrax Beach and move in a northwards direction, with the work site barricaded at all times for the safety of beach users.
Whilst public safety measures will be put in place, visitors to Port Beach will still be able to access open areas of the beach and water during the program of works and outside of construction hours.
Will there be any impact on parking at the Beach?
Sections of the southern car park, main car park and beach access points will be closed to the public to enable the safe movement of construction vehicles to and from the works area.
Will there be any impacts on traffic using Port Beach Road?
A Traffic Management Plan will be in place for the duration of the construction works however there is unlikely to be any impact on traffic movements along Port Beach Road.
How will rocks be removed from the beach?
Due to the sand screening process, rocks will be removed from the beach by use of an excavator and a sand screen operating from the beach area. Larger rocks and screened material will be transferred from the beach area to stockpile areas using earthworks machinery.
The location of stockpile areas are yet to be confirmed but will be within the Port Beach surrounds.
What will happen to the rocks screened from the beach and other site contamination?
Any suitable rock material will be stockpiled on site and reused as appropriate. Material unsuitable for re-use, due to contamination or otherwise, will be removed from site and disposed of appropriately.
What will the beach look like at the end of Phase 1?
The Phase 1 works will involve removal of the remnant seawall located at Sandtrax and screening of the beach sand along Port Beach for rock fragments. Apart from removal of the remnant seawall, the beach area will likely appear generally similar to its present condition at the completion of the works, albeit with rock fragments removed.
Sand nourishment via dredge project - Phase 2
- Environmental Protection Act 1986 (DWER)
- City of Fremantle Work Permits
- Fremantle Ports Permits
- Benthic communities and habitats
- Marine environmental quality
- Costal processes
- Marine fauna
- Flora and vegetation
What government approvals are required for the project?
Phase 2 – Sand nourishment via dredging will require several approvals and ongoing regulation under a number of different laws and regulations, these are:
The first step is to submit a completed approvals application through the Department of Water and Environmental Regulation, currently scheduled for September 2021.
Will there be any environmental impacts?
As part of the government approvals process, The City is presently conducting a range of studies addressing potential environmental impacts. These must show a detailed understanding of baseline, or pre-construction conditions and explain how potential impacts will be avoided or managed. Technical investigations will address the following environmental factors:
A social surroundings assessment will also be completed as part of this process to manage the potential impact on community.
An environmental management plan will also be prepared prior to the commencement of the Phase 2 program of works. This plan will be presented to the EPA as part of the approvals process. The monitoring and management requirements outlined in this plan will be implemented during the Phase 2 program of works to ensure the potential environmental impacts are mitigated.
Where will the City source suitable sand from for the sand nourishment project?
A number of options were investigated for sourcing the sand to be placed on Port Beach. Fremantle Ports Deep Water Channel was selected, as the sand from this area has physical properties most suited to the outcomes that we are targeting for Port Beach – including colour, particle size and composition.
Fremantle Ports is on standby and ready to support the City of Fremantle when it is in a position to commence the project.
How will the sand be placed on the beach?
The method by which sand will be transferred to the beach from the water will ultimately depend on the specific plant/machinery utilised by the Contractor to complete the works.
It is expected that the works will be suited to a Trailer Suction Hopper type dredge and the material will be placed onto the beach via rainbowing or pumped via pipeline. Example photographs of these methods are provided below.
Land based earthmoving machinery will be required to operate on the beach to manage receival of the sand and construct the beach profile.
Will dredging impact shipping and in the Deep Water Channel and recreational vessels in the vicinity of Port Beach
Temporary notices to mariners will be made through the Department of Transport’s website and other communication channels. The project will also liaise with Fremantle Ports Harbour Master.
How can I keep up to date about the project?
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How is the community being engaged about this project?
The City has undertaken broad engagement with the community and key stakeholders with an interest in the area throughout the Coastal Hazard Risk Management and Adaptation Planning (CHRMAP) process for the Port Leighton and Mosman Beaches Coastal Adaptation Plan (2016), investigation of coastal adaptation options as well as seeking inputs into shaping the final concept plan to address the coastal hazard impacts of erosion at Port Beach.
Please click here for more information on the consultation outcomes.
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Who do I contact about the project?
In the first instance, please visit www.mysay.fremantle.wa.gov.au/portbeach for more information on the project Alternatively please contact the City’s Customer Service Line on 1300 MY FREO (1300 693 736) or you can email email@example.com