Coastal vulnerability in Cockburn

The City’s beaches and coastline are invaluable natural and community assets. Our beaches are however vulnerable to natural processes such as erosion and inundation, the impacts of which are predicted to increase in severity with climate change and sea level rise.

C Y O’Connor Beach is at present an erosion hot-spot, requiring ongoing active management in the form of annual sand replenishment to maintain a useable beach and prevent the loss of land and coastal assets. The City’s other beaches, such as Coogee Beach, are expected to experience significant erosion problems as sea levels rise as predicted over this century. View the Detailed Coastal Hazard Mapping for the City of Cockburn coastline. Refer to the Coastal Vulnerability Study for further details regarding how to understand and interpret this hazard information.

How is the City responding to coastal vulnerability?

The City of Cockburn has in place a Coastal Adaptation Plan that was developed in collaboration with the CSCA using information from the earlier Coastal Vulnerability Study and Values and Risk Assessment processes.

The CAP guides the City in managing coastal risks and adapting to coastal changes in a sustainable and flexible manner.

Key measures the City has in place to manage coastal risks in alignment with the CAP include:

  • A Coastal Monitoring Program that tracks shoreline movements and identifies changes in the condition of beaches and coastal assets
  • Periodic sand replenishment of eroding areas such as C Y O’Connor Beach as required
  • Detailed planning and design for responses to coastal hazards at specific sites, such as the design of long term erosion protection measures for C Y O’Connor Beach
  • Creating a long-term Foreshore Management Plan for Coogee Beach
  • Ensuring planning schemes and controls are appropriate to the latest hazard information
  • Engagement with the community and stakeholders to raise awareness of coastal hazards and adaptation planning.

C.Y.O'Connor Beach

C Y O’Connor Beach has experienced persistent erosion since the late 1990s. Coastal engineering studies have identified that erosion will continue and the shoreline will recede further, putting assets and beach amenities at risk. The impacts of rising sea levels driven by climate change will further exacerbate the problem, with much of the foreshore lost if no action is taken.

As part of the City’s Coastal Adaptation Plan (CAP), a major coastal engineering design study is underway to design and select an approach for long term erosion protection along C.Y. O’Connor Beach. The final design selection will involve community engagement, and construction will be staged in line with funding and prioritising higher-risk areas.

What is the City doing in the short term to mitigate erosion at C.Y. O'Connor Beach?

Until the final design for long term erosion protection has been decided, the City has and will continue in the short term to engage in the following erosion mitigation practices.
Sand replenishment
To mitigate erosion and protect vulnerable lands and assets until longer-term solutions can be funded and built.

Sand replenishment in 2022

The City is undertaking sand replenishment at Coogee Beach and C.Y. O’Connor Beach in June/ July 2022 to manage erosion and maintain beach amenity and access. 

This year, a floating dredge is being used as, unlike previous years the sand is in deeper water, too deep for land-based excavators to reach. The floating dredge will take sediment from the seabed and pump it via a pipe to the sand replenishment locations on the two beaches.

The sand will look darker

A different extraction and transport method is being used compared to previous years, so the sand will initially look darker and more discoloured. However, it will naturally bleach and lighten within weeks to match the existing beach sand closely. The sand and sediment have been tested and are clean and safe for use on the two beaches.

The City is undertaking sand replenishment at Coogee Beach and C.Y. O’Connor Beach to manage erosion and maintain beach amenities and access. The process has begun and should be completed by July 2022.

View the video transcript.

Coastal Monitoring Program

To monitor changes to the coastline, including annual beach surveys and a time-lapse camera that records imagery of the coastline throughout the year.

Modular engineered fringing reef

A 100 m long engineered fringing reef has been installed at C.Y. O’Connor Beach. The reef is part of a coastal management trial project and is the first of its kind in Australia.

135 precast concrete reef modules have been installed offshore in front of Rollinson Road to break down wave energy reaching the shore and slow erosion rates.

The trial project will test the reef’s potential to control erosion while enhancing marine habitat and having minimal impact on the beach, unlike more conventional groynes and seawalls. The City and the University of Western Australia (UWA) will monitor the reef over the next few years to understand how it performs and affects the surrounding coastline. The reef could be reconfigured, reduced or expanded over time.

The project is part-funded by the WA Department of Transport Coastal Adaptation and Protection grant scheme. The reef has 
been designed and built by Henderson-based Subcon with coastal engineering support from M P Rogers & Associates and the University of Western Australia (UWA).

A geotextile sand container (GSC) seawall

A geotextile sand container (GSC) seawall has been buried within the dunes in front of Rollinson Road at C.Y. O’Connor Beach. 

The GSC will allow for a more stable dune to establish, reducing the occurrence of sand blowing into the nearby park and covering cycle paths. The City will revegetate and rehabilitate the dunes once the seawall is installed.

The GSC, 35 metres in length, will complement the modular engineered fringing reef installed offshore and act as a backstop to severe storm erosion. 

This project is part-funded by CoastWest and the City of Cockburn.

Cockburn Sound Coastal Alliance

The Cockburn Sound Coastal Alliance (CSCA) is a partnership between the cities of Cockburn, Fremantle, Kwinana and Rockingham and Perth Region NRM. The CSCA receives support from the Department of Transport, Department of Planning, Lands and Heritage, Department of Water and Environmental Regulation, the Cockburn Sound Management Council and the Department of Defence. 

The CSCA was formed to understand and respond to climate change impacts along the Cockburn Sound coastline. The CSCA recognises that coastal issues are common problems that cross local government boundaries and require integrated and collaborative approaches and solutions, including:

  • Building and sharing knowledge relating to the climate change impacts affecting the Owen Anchorage and Cockburn Sound such as sea level rise, erosion and inundation

  • Developing strategies to help address climate change impacts

  • Developing Coastal Adaptation Plans for its member councils

View the Coastal Adaptation Plans below. Each local government is now individually responsible for managing the implementation of coastal adaptation measures as it sees fit.

What is the Cockburn Sound Coastal Alliance doing?

The CSCA has taken a staged approach to climate change adaptation along the Cockburn Coast, which includes:

  • Stage 1: Coastal Vulnerability Study (completed in 2013)
  • Stage 2: Coastal values and Risk Assessment Study (completed in 2014)
  • Stage 3: Coastal Adaptation Plans (completed in 2016)

More information and contact

Visit the Cockburn Sound Coastal Alliance website opens in a new window for report appendices and more information.

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Contact

Address

9 Coleville Crescent,
Spearwood 6163

PO Box 1215, Bibra Lake DC,
Western Australia, 6965

Office opening hours:
8.30am to 4.30pm
Monday to Friday (excluding public holidays)

Language Support

Cockburn Nyungar moort Beeliar boodja-k kaadadjiny. Koora, yeyi, benang baalap nidja boodja-k kaaradjiny.
Ngalak kaadatj dayin boodja, kep wer malayin. Ngalak kaadatj koora koora wer yeyi ngalang birdiya.

City of Cockburn acknowledges the Nyungar people of Beeliar boodja. Long ago, now and in the future they care for country.
We acknowledge a continuing connection to land, waters and culture and pay our respects to the Elders, past, present and emerging.