Managing coastal erosion at Mettams Pool
Following a series of storms in 2009 that significantly impacted coastal infrastructure at Watermans Bay, the City commissioned a Strategic Coastal Processes Study, which was reported to Council on 9 May 2017. This study allowed the City to better understand the coastal processes, determine which areas of our coastline were most at risk and identify the nature of those risks.
One of the areas identified as most at risk from erosion was Mettams Pool and parts of West Coast Drive - which supports a popular coastal cycling and walking route and direct access to properties.
The City is now investigating a range of coastal engineering options, with the aim of balancing the protection of West Coast Drive with retaining or enhancing the attributes of Mettams Pool so valued by the community.
Why is the City investigating coastal engineering options for Mettams Pool?
In 2009, a series of large storms caused significant coastal erosion at Watermans Bay. This highlighted that the northern section of the City’s coastline between Trigg Island and Beach Road could be under threat from coastal erosion related to rising sea levels. The City commissioned a number of studies to better understand the situation and possible impacts on this section of coastline.
This investigation also identified that parts of West Coast Drive, an important District Distributer Road, which supports a popular coastal cycling and walking route and provides direct access to properties, could also be under threat. The City is now investigating a range of coastal engineering options, with the aim of balancing the protection of West Coast Drive with retaining or enhancing the attributes of Mettams Pool so valued by the community.
What is causing the coastal vulnerability at Mettams Pool?
The coastal vulnerability at Mettams Pool is a result of a number of factors including:
- Changes to sand movements
- Severe storm events which may be being exacerbated by climate change
- Sea level rise which is expected to increase significantly in the short term and substantially in the long term.
Due to a combination of the above, the coastal vulnerability is likely to increase significantly in the future. These factors are now putting coastal assets at greater risk and requiring a more strategic approach to coastal hazard mitigation and coastal adaptation.
What is coastal vulnerability?
Coastal vulnerability is the extent to which the coast is able to cope with the effects of erosion, storms and sea level rise. Coastal areas that are exposed, sensitive and less able to adapt are vulnerable.
What is coastal adaptation?
Coastal adaptation refers to the actions taken to respond to climate change and coastal vulnerability. It aims to maximise the gains and minimise the losses associated with coastal hazards.
What is coastal risk management planning and what engineering options will be considered for Mettams Pool?
Coastal risk management planning is about being ready to manage the risks to the assets and values within the Mettams Pool locality, which are associated with the impacts of changes to our coast line, by planning for the most appropriate decisions and options to implement over time.
A range of engineering options will be considered, largely informed by the outcomes of community feedback. Following this, a number of concept solutions will be presented and discussed at a community workshop.
How will the engineering options address erosion at Mettam Pool?
The risk management option/s chosen will determine how the infrastructure related to Mettams Pool can be adapted to optimise the unique features of Mettams Pool.
Coastal adaptation options may include, but are not limited to, relocating assets, placement of sand, structures such as vertical walls or revetments, as well as providing alternative ‘beach’ spaces for when the sandy beach is compromised.
How will the engineering options be evaluated?
The engineering options will be evaluated using a multi-criteria analysis frameworks, which will rank the engineering options based on the relative benefits of each option across a range of criteria. The analysis will consider the community values, environmental impacts, economic impacts and construction and operation/maintenance costs.
Will the engineering options impact facilities and amenity at and around Mettams Pool?
The community consultation process will help to establish the community values attributed to the facilities and amenity at Mettams Pool. Those values that are deemed to be very important, will be given greater consideration for accommodation within the engineering options. Some of these engineering options include:
- Universal access to beach and water
- West Coast Drive functionality
- Cycling and pedestrian routes
- Public toilets and changing room
- Viewing deck
- Dunes and vegetation.
How much will it cost to implement the engineering options and how long will it take?
Once the community have been consulted, then an initial design for the preferred option can be undertaken.
This will enable a cost estimate to be prepared to be reported to Council for consideration in future budgets.
Will the engineering options protect the functionality of West Coast Drive?
Yes. During construction works there will be temporary measures required to West Coast Drive, however, the ability to access properties, together with walking, riding and driving, will be maintained at all times.
Will the engineering options protect access to properties along West Coast Drive?
Yes. The engineering options will also consider risk management planning for West Coast Drive in the locality of Mettams Pool. If appropriate, modifications to West Coast Drive will also be considered.
Will the community continue to have access to Mettams Pool and beach area?
Yes. An outcome of the coastal adaptation works will be to retain access to Mettams Pool and the beach area, as most of any construction works will need to be accommodated within the road reserve.
The form of both the temporary and permanent access will be informed by community feedback.
Are there any other potential vulnerable areas along the coastline between Scarborough and Watermans Bay?
This is briefly outlined in the Coastal Hazard Mitigation Strategy webpage available on the City’s website.
What happens if we do nothing at Mettams Pool?
Without any coastal adaptation or mitigation works at Mettams Pool, erosion of the beach and dunes will continue.
This has already led to the closure of some beach accesses with a high risk that storm erosion could lead to the loss of the northern steps, change rooms and even the coastal shared path.
Are there any coastal risk management activities in place between Watermans Bay and Mettams Pool at the moment?
The City undertakes regular coastal risk monitoring and management along its coast. Recent activities completed between Mettams Pool and Watermans Bay include:
- The replacement of access stairs at James and Sorrento Streets
- Dune protection at James Street
- Cliff stabilisation and protection at Hamersley Pool.
Following very significant storm erosion in 2009, the City installed a Geotextile Sand Container (GSC) seawall at Watermans Bay to manage risk at that location. This has now stood the test of time and should provide adequate protection for at least 10 more years.
How can I provide my feedback on the engineering options?
Consultation is now closed while the project team incorporates community preferences into the design prior to a Report to Council.
Please make sure you check back in for updates or if you have any questions or further feedback yoiu wuld like ot provide, please get in touch with the City's Customer Contact Centre on (08) 9205 8555.
Do you have any questions about this project?
For more background information about this project please refer to the FAQs. If you can't find the answer, please get in touch to ask a question with Jon Offer, Engineering on (08) 9205 8555.
Community consultation open
Concept plans presented to the community
Preferred option design evaluated
Recommend option and draft strategy presented to Council
If you need this information in an alternative format, please contact the City's Customer Contact Centre on (08) 9205 8555.
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