A Coastal Hazard Risk Management Adaption Plan (CHRMAP) is a strategic planning document required for local governments under State Planning Policy and the Planning and Development Act 2005.

A Coastal Hazard Risk Management Adaption Plan or CHRMAP informs community and decision makers about the potential coastal hazards, the consequences of those hazards and outlines the actions needed to respond to predicted hazards (erosion and inundation (flooding)). The CHRMAP identifies areas and assets vulnerable to coastal hazards and develops strategies and controls to respond to changes in a way that considers social, environmental and economic values.

These coastal assets include both built and natural assets, which provide social, environmental, economic and heritage values to the community.

CHRMAPs inform other local planning documents by providing a framework for managing future coastal vulnerabilities. They allow informed decision making to occur by coordinating integrated and sustainable land use planning in the short and long term.

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 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, including any necessary changes to the City of Cockburn Local Planning Strategy, Local Planning Scheme and other relevant strategies and local planning policies.

The Department of Planning, Lands and Heritage define coastal values as the following:

Social:

Values are generally those that support quality of life, health and wellbeing of a community. Examples include beaches and foreshore reserves (environmental), car parking, and formal access paths (public infrastructure) to them.

Environmental:

Values are generally those that support coastal habitats for their geological, geomorphological, biodiversity and ecosystem integrity, landscape, seascape and visual landscape. Examples include ecosystem services provided by dune habitats for local flora and fauna, trapping of and storing sand, and providing a source of sand to replenish beaches following erosion events.

Infrastructure:

Values of the assets that support economic, social and environmental values. Infrastructure generally includes physical assets for transport, services and the community. Examples include buildings, road and rail (transport), water and sewer and electricity (services), and Surf Life Saving Clubs and foreshore infrastructure including footpaths, dune fencing and ablution facilities (community).

Economic:

Values are those that support industry, tourism, employment or relate to matters that have an economic implication.

The main coastal processes that are considered hazards are:

Erosion:

The gradual wearing away of the coastline due to wave action, currents, and human activities.

Inundation:

Flooding of coastal areas, often exacerbated by storm surges and rising sea levels.

Storm Surges:

Temporary rise in sea level caused by severe weather conditions, leading to coastal flooding.

Ongoing Sea Level Rise:

Long-term increase in sea levels due to climate change, which can lead to permanent inundation of low-lying areas.

Loss of Natural Habitats:

Coastal erosion and inundation can lead to the loss of important natural habitats, affecting biodiversity.

The CHRMAP identifies areas that could potentially be impacted by these hazards over the next 100 years, including projected storm events and sea level rise.

Coastal hazards are 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.

The coastal hazards are a result of a number of factors including:

• Changes to sand movements, in particular a reduction in the available sediment movement along the coastline.
• Severe storm events which are probably being exacerbated by climate change.
• Sea level rise which is projected to increase significantly in the short term and substantially (>900mm) in the longer term.

Due to a combination of these, the coastal hazards are expected to increase significantly in the future. These factors are already putting coastal assets at greater risk and requiring a more strategic approach to Coastal Hazard Risk Management and Adaptation Planning.

Coastal features that are affected by these hazards include sandy beaches; foreshore reserves; natural reserves; beach access; and retail, dining and club facilities.

Different management actions can be used to address the hazards and control their impact on the coastal features. Management actions include:

Sand replenishment:

Importing sand to re-establish the area of sandy beach, typically undertaken periodically.

Dune stabilisation and sand management:

Revegetating dunes and using structures to control human movement (e.g. fences, pathways), to improve habitat or reduce sand movement.

Dune construction:

Reconstructing sand dunes that no longer exist to control sand being blown by wind, or to provide improved habitat, or to restrict how far waves or floodwaters come onto land.

Reef construction or restoration:

Building artificial reef structures or restoring damaged natural reefs to provide habitat for marine life and modify wave conditions and movement of sand.

Offshore breakwaters:

Concrete blocks or boulders that are placed offshore to slow wave energy and movement of sand.

Seawalls:

A hard rock or concrete wall built along the coast used to prevent waves from eroding the foreshore reserve or to protect against flooding.

Geotextile Sand Container Wall:

A defensive barrier consisting of sand filled geosynthetic containers.

Groynes:

A barrier or wall perpendicular to the coast used to manage how waves move sand, typically by holding sand on one side of the structure.

Relocating facilities:

Instead of protecting coastal features where they are, they are moved or rebuilt at a new location.

If you visit, live, work or recreate near the City of Cockburn coastline, the CHRMAP will affect you and future generations.

Without any coastal adaptation or mitigation works at vulnerable beaches, erosion of the beach and dunes will continue. Based on geophysical investigations that have been undertaken this may, ultimately, lead to the loss of amenities along the Cockburn Coast extending a total length of approximately 17 kilometres, from Henderson South to North Coogee.

The Cockburn Coast extends a total length of approximately 17 kilometres, and areas bweteen North Coogee to Henderson South may be affected. This area includes:

• North Coogee
• Port Coogee
• Coogee Beach
• Woodman Point Reserve
• Woodman Point
• Australian Marine Complex
• Henderson South

If you have any more questions, please do not hesitate to contact the City’s Sustainability and Environment team on 08 9411 3444 or via email to [email protected] including the subject line heading ‘CHRMAP’.