Murrumbidgee Valley environmental water
Wetland in Yanga National Park, Lowbidgee Floodplain. Photo: Rachael Thomas, OEH.
The Murrumbidgee catchment covers 81,527 square kilometres. This includes a 1,690-km stretch of river with surrounding wetlands and a number of national parks, nature reserves and conservation areas with important wetland values.
The wetlands and rivers of the Murrumbidgee catchment hold important Aboriginal cultural values.
Environmental water management areas
Environmental water deliveries focus on two main areas of the Murrumbidgee:
- Murrumbidgee River Floodplain wetlands, located from Gundagai to the junction with Murray River - this includes the mid-Murrumbidgee wetlands site listed in the Directory of Important Wetlands in Australia
- the Murrumbidgee Irrigation Area (MIA) wetlands - this includes Fivebough and Tuckerbil Swamps listed under the Convention on Wetlands of International Importance (the ‘Ramsar Convention’) and Barren Box Swamp
- the lower Murrumbidgee floodplain, known as the ‘Lowbidgee’, watered by diversions from the Maude Weir and Redbank Weir – this includes the Nimmie-Caira and Redbank systems, and the Yanga section of Murrumbidgee Valley National Park.
This map shows the location of environmental watering areas in the Murrumbidgee Valley (PDF, 431KB).
The Murrumbidgee catchment contains 26 storage or diversion structures, making it one of Australia’s most regulated river systems, with substantial impacts on the water regime and availability of natural flows to floodplains and wetlands.
Benefits of environmental water
Environmental water in the Murrumbidgee valley supports:
- wetland vegetation communities, including river red gum, black box, common reed, spike rush, cumbungi, river cooba, water lilies and water ribbons
- habitat for a range of threatened, vulnerable and migratory birds, including Australian bittern, freckled duck, blue billed duck, painted snipe, red-necked stint and superb parrot
- habitat for the threatened southern bell frog
- variable river flows and refuge areas required by native fish, including Murray cod and trout cod.
Catchment condition 2011-12
Late 2011 and early 2012 was very wet for the Murrumbidgee. In March 2012 very heavy rain fell over much of the catchment - a one-in-100-year rain event in many parts. Following the rain, a major flood occurred all along the Murrumbidgee River, inundating many wetlands along the floodplain. The flood levels were comparable to the record 1974 flood.
Currently the wetlands of the Murrumbidgee River floodplain are in a much better condition than during the drought. Large-scale environmental flows combined with successive flood years have greatly improved red gum, black box and lignum health. However, thousands of dead mature trees remain.
Aquatic plant cover and diversity is only slowly recovering in some systems. Native fish populations in the lower reaches of the river have been severely impacted by successive low oxygen ‘black-water’ events.
Available environmental water in 2012-13
The 2012-13 water season will provide favourable volumes of environmental water because of wet catchment conditions and full storages. It is estimated that up to 400,000ML may become available for environmental water delivery during 2012-13.
This volume will be made up of NSW Environmental Water Holdings, Commonwealth environmental water and environmental water allocations provided for by the water sharing plan.
Environmental watering aims 2012-13
The Murrumbidgee Environmental Water Allowance Reference Group recommended that environmental water management for 2012-13 should acknowledge the wet catchment conditions and seek to build on the positive ecological responses seen in the last two years.
A primary focus for 2012-13 is to support native fish breeding and recruitment. During September and October 2012, OEH plans to deliver a flow downstream of Gogeldrie Weir (near Darlington Point) to provide river levels and flow cues required for breeding of Murray cod and other large-bodied native fish. Murray cod have been impacted by low-oxygen ‘black water’ events in the past two years. The managed flow event is the first of its kind in the Murrumbidgee and will be closely monitored.
Water will also be allocated for the private property wetlands on the North Redbank floodplain. Despite successive flood years, these wetlands have remained dry and isolated from the rest of the wetland system due to historical levees.
Some water will be held in accounts to maintain waterbird rookeries in the Lowbidgee wetlands, should the need arise. Rookeries could establish in North Redbank wetlands and Yanga National Park in late 2012 if the very wet conditions continue.
If the year turns dry, some water will be carried over to 2013-14 to ensure water will be available for watering in future years.
Annual Environmental Watering Plan 2012-13
The Murrumbidgee Valley Annual Environmental Watering Plan 2012-13 (120764mbidgeewp.pdf, 1.7MB) outlnes environmental water scenarios in detail.
Environmental Water Advisory Group
The Murrumbidgee Environmental Water Allowance Reference Group advises OEH on environmental water planning and watering priorities and is chaired by the Murrumbidgee Catchment Management Authority.
Partners
OEH manages environmental water in the Murrumbidgee catchment in partnership with:
Plans
Environmental water planning is supported by the following key documents and plans:
Reports on environmental water use
Environmental water use for 2011-12 is reported in the Environmental water use in NSW: Annual Report 2011-12.
Projects
The Upper Murrumbidgee Environmental Flow Enhancement Project is investigating the feasibility of lifting the operational flow limit at Gundagai to allow larger volumes of environmental flows than can currently be delivered. The current operational flow limit, specified in the water sharing plan is 32,000ML/day. Flows above 32,000ML progressively affect access to Mundarlo Bridge.
The project will investigate the potential environmental benefits and opportunities of delivering environmental water more efficiently, especially for mid-Murrumbidgee wetlands between Wagga Wagga and Hay.
Find out about information session dates.
Page last updated: 14 February 2013
