About wetlands

Wetlands take many forms, depending on whether they are on the coast, in estuaries, on floodplains and around rivers and lakes.

What is a wetland?

Gooragool Lagoon with waterlilies in bloomWetlands are areas of land covered or saturated with water. Wetlands can be covered with fresh, brackish or salt water that’s generally still or slow moving. The water can also sit just below the surface.

An area doesn't need to be permanently wet to qualify as a wetland. The flooding or saturation can also happen cyclically (at regular times) or intermittently (at random times).

The area just needs to be wet for long enough for its plants and animals to be adapted to – or even dependent on – wet conditions for at least part of their life cycle.

Many wetlands in inland NSW can be dry for 10 years or longer before being flooded after heavy rainfall and then stay wet for several years. This allows wetland plants and animals to regenerate and reproduce.

Where are wetlands found in NSW?

There are more than 20,000 wetlands across New South Wales.

Scientists from the Office of Environment and Heritage are updating their research into the locations of wetlands in New South Wales.

This includes a pilot project to build a comprehensive inventory of NSW wetlands.

In 2003, mapped wetlands covered about 4.5 million hectares of New South Wales – that’s about 6% of the state. 

  • Some of the biggest are in the Murray−Darling Basin, such as the Macquarie Marshes near Dubbo.
  • Most of the state’s other wetlands are on the coast, including estuaries and coastal lakes and lagoons.
  • There are a few freshwater wetlands on the tablelands and in the highest alpine regions, such as the lakes in Kosciuszko National Park.

This information is explained in detail in the report The Distribution of Wetlands in New South Wales (PDF 2MB).


Types of wetlands in NSW

Wetlands are diverse and have unique characteristics and wildlife, depending on where they are.

They can occur in a wide range of habitats, including rivers, floodplains, lakes, estuaries, swamps, bogs, billabongs, marshes and seagrass beds.

Wetlands can be classified into 5 types:

  1. Riverine wetlands, which are around rivers, creeks, streams and other waterways.
  2. Lacustrine wetlands, around freshwater lakes and reservoirs.
  3. Palustrine wetlands are inland freshwater areas that generally have plenty of trees and other vegetation.
  4. Estuarine wetlands are around estuaries.
  5. Marine wetlands are along the coast.

Fallen tree near water in a swamp surrounded by reedsRiverine wetlands are found around rivers, creeks, streams and other waterways. They include floodplains and marshes that are fed by these freshwater channels.

They may be permanently wet, or they may dry out during periods of low rainfall.

The Murray−Darling Basin has many riverine wetlands, including:

  • the internationally significant Millewa Forests
  • floodplain wetlands such as Mercedes Swamp and Two Bridges Wetlands near the Murrumbidgee River.

Dead trees in muddy waterLacustrine wetlands are inland freshwater lakes (PDF 3.6MB), man-made reservoirs and the areas around them.

Like riverine wetlands, they may be permanently wet, or they may dry out during periods of low rainfall.

Examples in New South Wales include:

  • Lake Pinaroo in Sturt National Park
  • alpine lakes in Kosciuszko National Park
  • upland lakes on the New England Tableland
  • Menindee Lakes near Broken Hill.

Waterhole and vegetationPalustrine wetlands are inland areas of non-tidal fresh water that have plenty of plants. They include inland floodplain swamps, marshes, shrublands, bogs and fens.

Examples in New South Wales include:

  • Macquarie Marshes north of Dubbo
  • Millewa Forests near Deniliquin.

Some types of palustrine wetlands, such as inland floodplain swamps, can be in a dry phase (PDF 1.8MB) for several years before they receive enough water to change to their wet phase (PDF 1.9MB).

They can exist next to or even within lacustrine, riverine or estuarine systems.

Lush vegetation around a water bodyEstuarine wetlands are found around estuaries where rivers meet the ocean. They may be partly enclosed by land but they open out to the sea.

They’re tidal and often have freshwater inflows from rivers, so they have varying levels of salinity (salt content). They include mangrove swamps and saltmarshes.

Examples in New South Wales include:

  • Myall Lakes near Bulahdelah
  • wetlands in Botany Bay
  • lower Hunter River near Newcastle
  • Tweed Estuary.

Bittangabee Bay, Ben Boyd National Park, coastal wetlandMarine wetlands occur along the length of the NSW coast. They cover the ocean area extending out from the coastline to 6 metres below the lowest tide.

They include ocean beaches, shallow ocean waters and rocky headlands and islands.