Coastal Hazard Risk Management and Adaptation Plan (CHRMAP)
Over the past year the City of Stirling has been preparing a Coastal Hazard Risk Management and Adaptation Plan (CHRMAP). This is a long-term plan that aims to make the coastline more resilient to coastal hazards, such as erosion and inundation. An important part about creating a CHRMAP is community involvement to understand how people value and use coastal assets, as well as feedback as to whether proposed mitigation strategies are acceptable to the wider community.
The City is now seeking feedback on the Draft Coastal Hazard Management and Adaption Plan. The plan will then go to Council for endorsement in Mid 2023.
What is a Coastal Hazard Risk Management and Adaptation Plan (CHRMAP)?
A CHRMAP is a strategic planning document that outlines management and adaptation pathways for areas and assets at risk of coastal hazards, such as erosion and inundation (flooding). Assets include both built and natural assets, which provide a range of values to the community, including social, environmental, economic and heritage values.
CHRMAPs provide the basis for planning instruments such as Local Planning Schemes, Local Structure Plans and Foreshore Management Plans, by presenting the context around existing and future coastal vulnerability and the framework for managing associated risk.
The CHRMAP is required under the State’s Coastal Planning Policy (SPP2.6), under the Planning and Development Act 2005. The CHRMAP will provide long term strategic direction, while identifying risk and required decision making in the shorter term.
What is the purpose of a CHRMAP?
The purpose of a CHRMAP is to:
- Set the framework for the assessment, by identifying coastal hazards (erosion and to a basic degree inundation), analysing vulnerability for specific assets, identifying and prioritising management and adaptation responses, and providing an implementation plan;
- Inform the community and stakeholders about potential coastal hazard risks; identify community and stakeholders’ values as well as key coastal infrastructure and assets at risk; and provide a clear pathway for the City of Stirling to address coastal hazard risks over time; and
- Provide strategic guidance for coordinated, integrated and sustainable land use planning and management decision-making by the City of Stirling, including any necessary changes to the City of Stirling Local Planning Strategy, Local Planning Scheme and other relevant strategies and local planning policies.
Why is the City of Stirling preparing a CHRMAP?
The vulnerability of assets within the Western Australian coastal zone to coastal hazards such as erosion and inundation is expected to increase in the future due to sea level rise resulting from climate change.
In 2019, Watermans Bay and Mettams Pool were included to the list of the state Coastal Erosion Hotspots prepared by the Department of Planning, Lands and Heritage and the Department of Transport. A range of public foreshore amenities were found to be prone to erosion hazard in the near to medium term (within 0 to 25 years), while large sections of public infrastructures assets such as the recreational shared use path, section of West Coast Drive and associated services (gas, power, water) were found to be at high risk due to coastal erosion in the medium to long term (as early as 2045).
It is understood that recent investigations were undertaken by the City to determine the extent of rock formations partially visible along the foreshore.
As such, the City has identified the need to engage specialist land use planning, community consultation and engagement, coastal engineering and economics consultants to review and update existing relevant studies to produce a CHRMAP for the study area in accordance with the CHRMAP Guidelines and SPP2.6, which is adopted by the City of Stirling and used to guide future decision making for vulnerable assets in its coastal zone.
How does a CHRMAP affect me?
If you visit, live, work or recreate near the City of Stirling coastline, the CHRMAP will affect you and future generations.
What is coastal vulnerability?
Coastal vulnerability is the extent that an area of coastline is susceptible to effects such as erosion, storms and ongoing sea level rise. It is assessed by combining:
- Exposure – the likelihood of impact;
- Sensitivity – the consequence if impact occurs; and
- Adaptive capacity – the ease with which assets or areas can adapt to the hazard.
Coastal areas that are exposed, sensitive and less able to adapt are the most vulnerable.
What work is proposed?
A key component of the CHRMAP is identifying the community’s coastal values as well as the valued natural and built assets along the coast, to inform the CHRMAP. The CHRMAP will cover the entire coastline of the City of Stirling while also incorporating /considering immediate areas to the north and south and will be delivered in eight stages.
- Stage 1: Establish the Context (with community consultation)
- Stage 2: Risk Identification
- Stage 3: Vulnerability Analysis
- Stage 4: Risk Evaluation
- Stage 5: Risk Treatment (with community consultation)
- Stage 6: Implementation Plan
- Stage 7: Monitoring and Review
- Stage 8: Final CHRMAP (with community consultation).
Yes! All commentary and feedback from the Mettams Pool formal engagementwill be considered in the CHRMAP project.
Who are the consultants?
The consultant team is composed of specialists in the respective fields of coastal engineering, environmental economics, statutory and strategic planning and community and stakeholder engagement. These are Cardno, the University of Western Australia and element.
- Stantec are the lead coastal engineering consultants for the CHRMAP project. They have delivered more than 5 CHRMAPs to-date throughout Western Australia.
- element has been at the forefront of town planning and urban design in Western Australia for over three decades and bring a highly developed understanding of strategic planning and statutory planning into the project team. In addition to this, they have a highly skilled team of engagement specialists who will be leading the community and stakeholder engagement for the project.
- The University of Western Australia are the lead environmental economists for the project. They have been at the forefront of research in better understanding the economic value provided by natural assets, such as beaches and coastal vegetation.
How can I be involved?
The final round of consultation is open until 2 February 2023.
When will the CHRMAP be completed?
The City anticipates the final CHRMAP, developed in consultation with the community and key stakeholders, will be delivered towards the end of 2022.
Can we remove the rocks at Mettams Pool?
This has been considered, however, the answer is no for two reasons:
Firstly, Mettams Pool is included in the Marmion Marine Park which means that any work below the high water mark would require permission from the State Government who have indicated that this would not be approved.
Secondly, the rocks when exposed are part of the natural protection that enables beach sand to be retained behind them and helps to minimise erosion to the dunes supporting West Coast Drive. The City has received advice that removal of all or part of these rocks will increase the risk of erosion to both the beach and the supporting dunes.
Aren’t you already doing work to mitigate the impact of coastal hazards along our coastline?
That’s right. We have just completed ramp upgrade works at Mettams Pool to address the immediate, short-term impacts from coastal erosion on these assets and maintain universal access to the beach. Sand nourishment is also planned for Mettams beach as a short term adaptation activity which will provide added resistance and sand supply to the area. Beach nourishment also recognises the value that a wider and deeper sandy beach provides to our community which we have acknowledged from previous engagement in 2017 regarding Mettams Pool. However, the purpose of this report is to work with the community to develop a long-term plan for managing coastal hazards on the coastline, looking towards the next 50 to 100 years, and reviewed periodically.
Why do we need your feedback?
Input from the community and key stakeholders will impact the level of priority given to a range of assets on the coast. By having your say on your most beloved coastal assets, you will help the team to identify the high-priority considerations along the coast. Early next year, we will be holding two ‘Community Scenario Workshops’ where we will identify and prioritise key assets with the community as well as seek feedback on the preferred adaption options with you. Consequently, this will guide the draft CHRMAP report.
How can I be involved?
Stage 1: Consultation commences
October 2021 to December 2021
Stage 2: Risk identification
September 2021 to November 2021
Stage 3: Vulnerability analysis
November to December 2021
Stage 4: Risk evaluation
December 2021 to January 2022
Stage 5: Risk treatment and further community engagement
December 2021 to March 2022
Stage 6: Implementation plan
February 2022 to March 2022
Stage 7: Monitoring and review
Stage 8: Final CHRMAP developed and consultation with the community on the plan
March 2022 to October 2022
Stage 9: CHRMAP goes to Council for endorsement
Coastal hazards have the potential to impact coastal areas and assets. They have always existed along our coastlines. Coastal hazards are not necessarily associated with climate change, but they will be exacerbated by sea level rise in the future.
Erosion is the main coastal hazard impacting the City of Stirling coastline. Erosion can occur in a short time period - for example due to a storm event, or over a longer period of time - as the shoreline gradually retreats due to rising mean sea level or changes/variability in local coastal process.
If erosion occurs where assets exist, the damage is generally permanent. Erosion, however, is not necessarily permanent with sandy beaches often eroding and recovering seasonally. Both erosion and inundation hazard extents will be mapped for the CHRMAP, at various timeframes from present day to 2120.
For more information, please contact Frank Strever, Engineering Services on (08) 9205 8555.
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