Coastal Erosion


Beach Erosion

Collaroy-Narrabeen Beach is the most vulnerable beach to erosion from coastal storms in Warringah and is ranked the third most at risk area from coastal processes in Australia. To help manage Warringah’s beautiful coastline, Warringah Council has several measures in place to mitigate coastal erosion.

Sand Replenishment and Beach Nourishment

We source sand from local building sites to supplement sand and/or build up sand on eroded beaches. Sand is also dredged periodically from the entrance of Narrabeen Lagoon and is used to replenish Collaroy-Narrabeen Beach.

Sea Walls

Council is currently preparing a Coastal Zone Management Plan for Collaroy-Narrabeen and Fishermans Beach and many people have asked; "will a seawall be built?". The answer may surprise you. Many seawalls already exist along Collaroy-Narrabeen and they significantly reduce the risk to development of coastal erosion. Most of them are sloping rock walls on private property, that are buried under sand for most of the time. They are usually only visible after major erosion events. The future of seawalls will be determined by the Coastal Zone Management Plan.

Dune Management

Dunes are an integral part of our coastal environment and support valuable communities of plants and animals. The plants in turn stabilise the dunes, preventing them from being blown inland. Dunes are ‘nature’s seawalls’. They are flexible structures which provide protection by sacrificing themselves at times of storm attack. Without the protection of the dunes, the beaches themselves are more at risk of erosion.

We manage the coastal dunes along the Warringah coastline in accordance with the NSW Coastal Dune Management Manual. It is important to keep to the paths on the dunes and not to go inside the dune fencing. Walking through the dune vegetation can destroy the plants, which in turn can destabilise the dunes and cause erosion.

Coastal Erosion Emergency Action Subplan

The Subplan identifies the risks and actions Council can take before, during and after a coastal erosion emergency. It also includes information on coastal protective works for private landowners.

Collaroy-Narrabeen Beach Management

The management of coastal hazards at Collaroy-Narrabeen Beach is guided by the Coastal Zone Management Plan for Collaroy-Narrabeen Beach and Fishermans. Action to preserve and protect this vulnerable beach is already underway and includes ensuring that development along Collaroy-Narrabeen Beach considers current and future hazards of wave impact and coastal erosion.