Beaches regularly undergo cycles of erosion or growth in response to tides, wind and waves. This can make coastlines hazardous areas for development. Here we look at the threats to developed coastlines from coastal erosion. Also the impacts and issues surrounding ongoing urban development.
Urban development is at risk of damage from these coastal changes and by changing coastal stability, development itself can actually increase erosion risks.
Buildings, roads and homes within the "active" beach system become vulnerable to extreme weather conditions, by sand drift, storm-water erosion and receding shorelines.
Sand Replenishment and Beach Nourishment
There are several measures we take to lessen coastal erosion. We source sand from local building sites to supplement sand and 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 and Dune Management
Many seawalls already exist along Collaroy-Narrabeen significantly reducing further coastal erosion. Covered by sand, they’re usually only visible after major erosion events. The future of seawalls will be assessed and determined by the Coastal Zone Management Plan.
Dunes are ‘nature’s seawalls’ and an integral part of our coastal environment. We manage the coastal dunes following the NSW Coastal Dune Management Manual. It’s important everyone stays on the dune pathways. Walking through the dune vegetation can destroy the plants, which in turn destabilises the dunes, furthering erosion.
Coastal Erosion Emergency Action Sub-plan
This Sub-plan identifies the risks and actions we can take before, during and after a coastal erosion emergency. It includes information on coastal protective works suggested for private landowners.
Collaroy-Narrabeen Beach Management
Collaroy-Narrabeen Beach is the beach most vulnerable to erosion from coastal storms on the Northern Beaches. It’s ranked Australia’s third most at risk area from coastal processes.
Action to preserve and protect this beach is already underway including development and planning considerations regarding future hazards of wave impact and coastal erosion.
Stay safe. The State Emergency Services has more information about preparing for coastal erosion and being storm-safe.