Environmental issues

Water

Macquarie Valley environmental water

brown water and grass in foreground with blue sky in background

Macquarie Marshes Nature Reserve 2010, showing vegetation response to environmental water flow following drought. Photo: Neal Foster.

The Macquarie River catchment covers 75,000 square kilometres, extending from the Blue Mountains to the Darling Riverine Plains. North of Warren, the Macquarie River spills into the iconic Macquarie Marshes, which extend over 100 km. Downstream of the Macquarie Marshes, the Macquarie River re-forms and flows to the Barwon River.

Environmental water delivery focus

The Macquarie Marshes are the catchment’s largest wetland system and the main focus of managed environmental water releases. The Marshes include a range of wetlands from semi-permanent marshes and lagoons to ephemeral wetlands that are only inundated by the largest floods.

Macquarie Marshes Nature Reserve and parts of the privately owned properties ‘Wilgara and 'U-Block’ are listed under the Convention on Wetlands of International Importance (the Ramsar Convention). More than 500 cultural heritage sites are recorded in the Macquarie Marshes, the traditional country of the Wailwan people.

Environmental water can also target:

  • Cudgegong and Macquarie River channels, for in-channel environmental benefits and to ‘drown out’ weirs to allow fish passage
  • the unregulated lower Macquarie River downstream of the Marshes
  • the distributary creek systems north-west of the Macquarie River, including Crooked, Duck, Marra and Gunningbar creeks.

View a map showing the location of environmental watering areas in the Macquarie Valley (Macquarie2013.pdf, 377 KB).

Benefits of environmental water

Environmental watering in the Macquarie catchment supports:

  • wetland vegetation communities, including river red gum, reed beds, water couch meadows, mixed marsh, river cooba, black box and coolibah
  • habitat for waterbird species that nest in colonies, including egrets, herons, cormorants, spoonbills, ibis and darter (the Marshes have supported some of the largest waterbird breeding events in Australia’s recorded history)
  • habitat for other waterbirds, including terns, ducks, swans, grebes, bitterns and stilts
  • summer harbour for various migratory wader species, including godwits, sandpipers and Latham’s snipe
  • habitat and opportunities for breeding and movement of vulnerable native fish, including Murray cod and silver perch.

Catchment condition 2012-13

Conditions in the Macquarie Marshes have been improving since 2010 and the conclusion of the millennium drought, although there has been a marked fluctuation between very wet and very dry short-term cycles. Despite recent flood conditions and application of environmental water, the Marshes have dried considerably leading into 2013-14, with an absence of water on both the inner and outer floodplain. Good subsoil moisture and shallow groundwater levels have provided some protection to the Marshes during the recent drying phase.

Assessment of vegetation condition in the Marshes confirms wet grasslands, sedgelands and rushlands have recovered strongly over the last three years, while recent wet conditions have also favoured vegetation growth within waterbodies. There is now some evidence of improving canopy health and recruitment in large areas of floodplain eucalypt woodland.

Available environmental water in 2013-14

Moderate conditions currently exist in the Macquarie-Castlereagh Valley. At the start of the water year, Burrendong Dam was at 43% capacity, while Windamere Dam was at 56%, with high security at 100% and general security allocations at 0%.

Environmental water holdings in the Macquarie-Castlereagh are available from an Environmental Water Allowance under the current Water Sharing Plan and environmental water held by the State and Commonwealth governments as licensed entitlements. Based on proposed carryover and the starting Available Water Determination of 0% for 2013-14, a volume of approximately 115,000 ML of environmental water is available at the commencement of the 2013-14 water year.

Environmental watering aims for 2013-14

The Macquarie and Cudgegong Environmental Flows Reference Group (EFRG) has considered the conditions of assets, water availability and climate forecasts and recommended that under the forecast ‘moderate’ resource assessment, the management outcomes for the water year are to maintain ecological health and resilience.

The aim of environmental watering in the Macquarie-Castlereagh system in 2013-14 will be to increase the resilience of permanent and semi-permanent wetlands by replenishing soil moisture and meeting the water requirements of wetland vegetation that requires annual inundation while ensuring adequate water is available for the next 12-24 months if dry conditions continue. The EFRG has recommended that water deliveries for 2013-14 also consider the needs of migratory waterbirds and native fish.

For further information contact Justen Simpson, Senior Team Leader, Environmental Water Governance, NSW Office of Environment and Heritage: phone (02) 6229 7140.

Annual Environmental Watering Plan 2013-14

The Macquarie Valley Annual Environmental Watering Plan 2013-14 (130581MacqAEWP.pdf, 2MB) outlines the environmental water scenarios in detail.

Environmental Water Advisory Group

The Macquarie and Cudgegong Environmental Flows Reference Group advises OEH on planning for and delivering environmental water through the water season.

Partners

OEH manages environmental water in the Macquarie Valley in partnership with:

Plans

Environmental water management is supported by:

Reports on environmental water use

Environmental water use for 2012-13 is reported in Environmental water use in NSW: Outcomes 2012-13.

Key wetland and environmental water projects

The Lower Macquarie Floodplain Resilience Model Project (PDF, 1.1MB) is being undertaken by the Central West Catchment Management Authority in partnership with a range of stakeholders including OEH. It focuses on identifying and describing the environmental, social and economic characteristics, processes and thresholds present in the Macquarie Marshes and lower Macquarie floodplain systems.

Page last updated: 13 March 2014