Estuaries of NSW

What is an estuary?

Estuaries are places of transition. They are where freshwater draining from our coastal catchments mixes with ocean waters. Broadly speaking, estuaries are semi-enclosed waterbodies with open or intermittently open connections with the ocean.

Estuaries in NSW vary in their shape and size, ranging from large coastal embayments and drowned river valleys, such as Port Stephens and the Hawkesbury River, to coastal lakes, such as Lake Macquarie and Wallis Lake, and smaller intermittently open coastal lakes and lagoons, such as Manly Lagoon and Tabourie Lake. Estuaries also support many different habitat types and species.

Estuaries are one of the most important of the state's natural resources and are some of the most intensively used areas of NSW. Just over 80% of the state's population live in catchments surrounding estuaries.

NSW estuaries are valuable community assets, providing many ecosystem services and are relied on for commercial and cultural activities, tourism and recreation.

The way we use estuaries can affect how they function and their overall condition or health.

Estuaries are subject to pressures from human activities as well as natural events such as storms and floods. Common threats to estuary health include increased nutrients and algal blooms, loss of habitat and biodiversity, contaminants and pollutants, accelerated rates of sedimentation, disturbance of acid sulfate soils, changes to freshwater and tidal flows, invasive species and climate change.

The overall target for managing NSW estuaries is that by 2015 there is an improvement in the condition of estuaries and coastal lake ecosystems (NSW State Plan, 2010). 

Through the Estuary Management Program, the Office of Environment and Heritage (OEH) collects data and provides technical assistance and funding to help improve the health of estuaries.

Information on estuaries in NSW

Assistance to improve estuary health

More Information

Further information may be obtained by contacting the relevant office listed below:

 North Coast  (02) 6627 0206
 Hunter/Lower North Coast  (02) 4904 2594
 Sydney  (02) 9895 6267
 South Coast  (02) 4224 4164

Don’t open that entrance – it’s an ICOLL

There are about 70 ICOLLs, or intermittently closed lakes and lagoons, along the NSW coast. Most occur south of Sydney. ICOLLs alternate between being closed or open depending on rainfall in the catchment and the movement of sand as a result of wave action, tides and winds.

This short animation tells the story of what can happen to ICCOLS and their residents if the entrance is artificially opened.

Page last updated: 14 October 2015