Coastline Management

Page Updated: August 10, 2012

Warringah Council has 14km of coastline that is characterised by a series of bays, generally backed by coastal dunes and reserves that stretch from North Narrabeen to Queenscliff rock pool. Warringah's nine beaches are highly valued by the community and tourists.

Beaches
Stormwater
Dunes
Coastal Erosion
Coastal Erosion Emergency Action Subplan for Beaches in Warringah
Collaroy-Narrabeen Beach Management
Coastal Lands Plan of Management
Sydney Coastal Councils Group
Coastal Monitoring and Beach Nourishment

Beaches

Warringah beaches have adjusted to their present form relatively recently (in geological terms). About 17,000 years ago sea levels started to rise as the last ice age ended. About 6,000 years ago the sea level stabilised to near current levels. This rise in sea level ‘pushed’ sand ‘upwards’ and deposited it within the current bays, giving rise to the familiar sandy beaches seen along the NSW coast. Click here for more information on Warringah's beaches.

Stormwater

Much of the rain that falls on the coastal areas of Warringah ends up as stormwater, flowing down creeks and pipes to our lagoons and the ocean. This means that the quality of stormwater draining off our land affects the water we swim in at our beaches. Council works hard to improve stormwater quality through community education on the human causes of impacts, and by installing special traps on stormwater drains. For current water quality at our beaches, visit Beachwatch.

Dunes

Coastal dunes are an important part of the Warringah coastline. They are a special habitat for a range of animals and offer protection from heavy seas. Council actively stabilises and rehabilitates the coastal dunes at Narrabeen, Long Reef, Dee Why, Curl Curl and Freshwater beaches. Council manages its coastal dunes in accordance with the NSW Coastal Dune Management Manual (DLWC 2001).

Coastal Erosion

NSW has an established framework for managing coastal erosion risks through the NSW Coastal Policy (1997) and the Coastal Protection Act 1979. This enables local councils, with financial and technical support from the State, to undertake coastal hazard studies and develop management plans which then inform land-use planning, development controls and coastal activities. More on Coastal Erosion Management in NSW.

Of the nine beaches in the Warringah LGA, it is Collaroy-Narrabeen that presents Council with its greatest coastal erosion challenges. Collaroy-Narrabeen Beach has experienced a long history of storm damage and coastal erosion. Nationally, the beach is ranked third most at risk area from coastal processes.

Coastal Erosion Emergency Action Subplan for Beaches in Warringah

Warringah Council, in conjunction with consultant Worley Parsons, has developed a Coastal Erosion Emergency Action Subplan for Beaches in Warringah (PDF).

The Subplan and its accompanying Reference Document identifies risks associated with coastal erosion and the actions Council intends to take before, during and after a coastal erosion emergency. The Subplan also identifies requirements relating to landowner emergency coastal protection works

Appendices to Reference Document

Appendix A - Historical Setting

Appendix B - Australian Approaches to Coastal Emergencies

Appendix C - International Approaches to Coastal Emergencies

Appendix D - Analysis of Photogrammetric Data

Appendix E - Depth of Closure for Bruun Rule

Appendix F - Evaluation Emergency Protective Measures

Appendix G - Inventory Warringah Coastal Properties

Appendix H - Risk Assessment

Two community forums were held during the Subplan’s preparation to provide the community with an opportunity to learn more about the Subplan and how it relates to reforms of coastal erosion management.

More information and webstream of 2010 CEEAP Forum.

Collaroy-Narrabeen Beach Management

Warringah Council's management of Collaroy-Narrabeen Beach is guided by the Collaroy Narrabeen Coastline Management Plan. Council works closely with the State Government and local community to implement the Plan. The Plan is in accordance with the NSW Coastal Policy (1997) and Coastline Management Manual (1990) and was formally adopted by Council in 1997.

Since adopting the Plan, Council has carried out a number of the recommended actions aimed at preserving and protecting the beach as a national asset for public recreation and amenity; and ensuring that building and development along Collaroy-Narrabeen Beach has regard to the current and future hazards of wave impact and coastal erosion. Some of the actions have not proven to be sustainable in the long term, eg purchase of properties, or popular with the community, eg a seawall.

Coastal Lands Plan of Management

Another key document that guides Council's management of the Warringah coastline is the Coastal Lands Plan of Management. The Coastal Lands Plan of Management covers all public open space located on or adjacent to Warringah's coastline, with the exception of Dee Why Lagoon and environs and Griffith Park, which are the subject of two separate Specific Area Plans of Management - the Dee Why Wildlife Refuge Plan of Management and the Griffith Park Plan of Management.

The Coastal Lands Plan of Management is designed to provide the overall framework for coastal management and should be used in conjunction with other key documents that provide management guidance for the coast.

Sydney Coastal Councils Group

Warringah is also addressing coastal management concerns through its participation in the Sydney Coastal Councils Group. The Sydney Coastal Councils Group (SCCG) is a regional organisation made up of 15 Councils that provides project facilitation and coordination on environmental and natural resource management issues that relate to the sustainable management of the coastal urban environment including the impacts of climate change.

Coastal Monitoring and Beach Nourishment

Ongoing Council actions include the quantitative and independent monitoring of coastal processes (including sand erosion and deposition) at Collaroy-Narrabeen Beach, which is undertaken in conjunction with the Water Research Laboratory, School of Civil and Environmental Engineering at the University of New South Wales. More on coastal processes monitoring.

Council also undertakes ‘Beach Nourishment’ activities with sand sourced from local building sites and other sources. ‘Beach Nourishment’ is the supply of sediment by mechanical means to supplement sand on an existing beach or to build up an eroded beach (Coastline Management Manual 1990).

‘Sand replenishment’ is also undertaken periodically at Collaroy/Narrabeen beach using sand cleared from the entrance of Narrabeen Lagoon.