Environmental issues


Lachlan Valley environmental water

Booligal wetland with waterbirds.

Straw-necked ibis and freckled ducks in Booligal Wetlands, Lachlan Valley, during spring 2010. Freckled ducks are listed as vulnerable in NSW. Following an environmental water release, four pairs of these ducks nested and bred in dense lignum that also supported nesting of over 60,0000 pairs of straw-necked ibis. Photo: Paul Packard, OEH.

The Lachlan catchment has an area of 90,000 square kilometres, extending from the Great Dividing Range to the Great Cumbung Swamp on the Riverine plains. The Lachlan has three areas of particularly high environmental value:

  • Booligal Wetlands
  • Great Cumbung Swamp
  • Lachlan Swamp.

All are listed in the Directory of Important Wetlands in Australia. Other significant wetlands include Merrowie Creek Wetlands, Lake Brewster and Lake Cowal. The Lachlan River, and wetlands in particular, hold important Aboriginal cultural values.

View a map showing the location of environmental watering areas in the Lachlan valley (Lachlan2013.pdf, 845KB).

Benefits of environmental water

Environmental water in the Lachlan supports:

  • wetland plant communities, including black box, river cooba, common reed, extensive areas of riparian fringing river red gum forest - the Great Cumbung Swamp has one of the largest stands of river red gum in NSW
  • waterbird breeding and foraging habitat - in good condition, the Lachlan wetlands and floodplains support breeding events for tens of thousands of colonial nesting birds, such as straw-necked ibis and glossy ibis; when water levels are suitable, Lake Brewster supports large breeding colonies of pelicans
  • habitat for birds listed under international migratory bird agreements, including great egret, glossy ibis, sharp-tailed sandpiper, common greenshank, Latham’s snipe, painted snipe and white-bellied sea-eagle
  • habitat for birds listed as vulnerable, including the Australasian bittern, blue-billed duck and freckled duck
  • maintenance of drought refuges for water birds
  • maintenance of fish refuges and variable flow conditions, which are required by native fish to breed and disperse
  • wetlands listed as endangered ecological communities, including the lowland section of the Booligal Wetlands, the Great Cumbung Swamp and Lachlan Swamps.

Adaptive management of environmental water

The Lachlan is a long, regulated river system with highly variable flows. In dry years, no flows reach the end of the system. Many of the key wetlands are in the lower end of the catchment, on the extensive unregulated effluent creek system or the floodplain. Relatively high channel flows, or even overbank flows, are required to inundate the wetlands.

Environmental water holdings are managed in conjunction with other river flows to:

  • minimise adverse consequences of water delivery
  • maximise the likelihood of water reaching its target
  • maximise the ecological benefits of applying environmental water.


Environmental water planning is supported by the following key documents and plans:

Page last updated: 08 December 2014