Inlands wetlands come in many forms and can be freshwater, brackish or saline. This page describes the features of different inland wetland types.
Lake Ulena, Brindiwilpa, is an example of a playa lake. Photo: Sam Davis
- Playa lakes (freshwater)
- Salt lakes (saline)
- Occur on the alluvial sandplains and dunefields of western NSW.
- Not located on a river floodplain.
- Fills predominantly from rainfall, groundwater or a local catchment.
- Characteristically have very high rates of evaporation
- Duration of inundation (wetting) variable depending on inflows and seasonal evaporation rates.
- Experience extended dry periods.
- Vegetation is usually absent altogether in the large playas and salt lakes. The lakebeds are commonly bare when dry and when flooded except for algae and sea tassel which may grow in the more saline wetlands.
- The fringes of salt lakes and the beds of smaller saltpans are dominated by samphire, saltbushes, copperburs and bluebush.
- Claypans are typically vegetated with canegrass.
- Some terminal playas and claypans support fringing lignum swamps. Other floodplain species such as river red gum, river cooba, black box, yapunyah and coolibah also occur around the margins of the freshwater playas and claypans.
- Support extremely high waterbird populations when flooded.
Permanent inland wetlands
Lake Menindee. Photo: Dayle Green
Lakes and billabongs formed from impounded channels.
- Wakool-Tullakool Evaporation Basins
- Lake Menindee
(Note: there are no naturally occurring wetlands of this type in NSW)
- Dominated by open water which is filled from a river under regulated flow conditions or which is permanently impounded by a structure.
- Dominant source of water for most is from stream flows, however for some wetlands tailwater is the dominant source.
- Dead trees are often present in the water or around the edges of the wetland.
- Common reed is often around the shoreline while cumbungi may occur in water up to 1.5m deep around the margins.
- Provides a permanent habitat for aquatic weeds.
- Wetlands supplied by irrigation tailwater are affected by high levels of nutrients, pesticides and herbicides.
- Large permanent wetlands are often over used for recreation (such as boating and water skiing).
- Large permanent wetlands may raise local water tables and exacerbate salinity.
Macquarie Marshes. Photo: DNR
- Wanganella Swamp,
- Parts of the Macquarie Marshes,
- Great Cumbung Swamp
- Located on the floodplain of a river which is subject to permanent or intermittent river flows and is dominated by reeds.
- Do not have extensive areas of open water.
- Occur in relatively deep channels or depressions on the floodplains of major rivers, often occuring extensively at the end of the river system.
- Rely on surplus or regulated flows from a river as their main water source.
- Dominant species are common reed and cumbungi which usually occur as dense pure stands depending on the specific hydrology of the site (cumbungi if wetter or common reed if drier).
- Extremely efficient at removing and re-cycling nutrients from the water.
- Provide sheltered habitat for refuge and breeding of waterbirds.
- Provide dense habitat for feral animals, such as pigs.
Aerial view of Cumbung Swamp. Photo: Dayle Green
Semi-arid canegrass swamps
- Internally draining basin, unconnected to a river or creek.
- Dominated by canegrass.
- No extensive open water.
- Rely on rainfall for wetting.
Canegrass swamp near Tilpa. Photo: Dayle Green
Cattleyard swamp. Photo: Sam Davis
Inland floodplain wetlands
Lakes, Lagoons, Billabongs.
- Dominated by open water which is located on the floodplain of a river, and which is subject to a cycle of flooding and drying.
- Large areas of open water when flooded.
- Vegetation restricted to the margins of the wetland.
- Seasonal or intermittent flooding from a river as the main source of water. Between floods rainfall and local runoff may result in brief inundation of the wetlands.
- The most important characteristic which separates the intermittent lakes and lagoons from permanent inland wetlands is the drying and reflooding process.
- flood and dry on an annual basis
- be wet most years but dry for occasional periods
- be dry most years but flood occasionally.
- In large intermittent lakes, lignum is common around the edges of the wetland where the water is not too deep. Floodplain woodlands of black box or coolibah usually occur in a narrow fringe surrounding the lakes.
- Oxbow lagoons are generally located within the zone of riverine woodland adjacent to the river. They support river red gums along their banks, often in association with black box or coolibah. Understorey species commonly include lignum or nitre goosefoot.
- Valuable and productive areas for waterbird breeding and feeding.
- Provide sheltered nursery areas for the survival of young fish species.
Narran Lakes Photo: DLWC
- Parts of the Macquarie Marshes
- Located on inland floodplains which are filled by surplus or flood flows and dominated by lignum vegetation.
- Typically found at the end of the river system. It is characteristically found in extensive braided floodways or overflows associated with the rivers of central and western New South Wales, but also occurs in smaller depressions and billabongs adjacent to the river channel.
- Rely on intermittent flooding from rivers as their main source of water.
- Lignum is the dominant species, often forming large rounded plants up to 2m in height and forming a dense cover where inundation is more frequent.
- Associated tree species include coolibah, black box, river red gum, yapunyah and river cooba. These often occur around the margins of the wetlands or scattered throughout the lignum.
- Valuable breeding sites for colonial waterbird species such as ibis and spoonbills which trample the bushes to provide nests.
Mercoola Creek lignum. Photo: Sam Davis
Inland floodplain forest and woodland
- Located on the river floodplain dominated by tree species which rely on shallow flooding. This wetland type includes river red gum forests and coolibah and black box woodlands.
- Rely on surplus flows or overbank flooding as their main source of water.
- Understorey usually dominated by plants which can withstand inundation.
River Red Gum Woodland, Murrumbidgee. Photo: Dayle Green
Inland floodplain meadows
- Shallow wetland located on the floodplain of an inland river which is dominated by grasses, herbs, sedges or rushes.
- Occur in association with riverine forests and woodlands, and in shallow depressions on the floodplain.
- Rely on shallow seasonal or intermittent flooding from a river as their main source of water. Between floods, groundwater and rainfall can help maintain water levels in wetlands.
- Dominant grass species include spiney mud grass, barnyard grass, mat grass and water couch.
- When flooded, are an important feeding habitat for a variety of waterbirds, particularly ibis, herons, egrets, spoonbills and some ducks.
- Provide dissipation and distribution of floodwaters from a catchment.
Merrorie Creek wetlands. Photo: Dayle Green