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Water management facts

Drought and water allocations

  • Water allocations and entitlements vary from state to state and these differences mean that some entitlement holders have an allocation, while others have little to none.
  • In times of drought, allocations are reduced the same way for all water users—including the environmental water holders.
  • Through the Basin Plan, water is prioritised for critical human needs—for drinking and household water before being allocated for any other use.  In severe drought when rivers cease to flow, it’s not physically possible to supply water, and this has now occurred in some towns in the northern Basin.
  • The year 2018 was the hottest year on record for the Murray-Darling Basin. Extremely low rainfall such as during the past two years has only occurred on two other occasions since 1900.

Read the latest MDBA drought update

River Operations: The Barmah Choke and water delivery

  • The Barmah Choke is a narrow section of the River Murray that runs through the Barmah–Millewa Forest.
  • The Choke restricts the flow of the River Murray to around 7,000 megalitres per day.
  • River managers consider the limitations of using the Choke when delivering water downstream.
  • The Choke has a trade restriction to protect delivery to existing entitlement holders and to maintain the river environment in the Choke.
  • When water goes through the forest most of it makes its way back into the river again downstream of the Choke.

More about the Barmah Choke

Water losses in the River Murray

  • Losses occur when water evaporates, is used by plants, or seeps into the ground. The Basin has an extremely high evaporation rate.
  • These losses are factored into water orders through ‘conveyance’—which is the water needed to deliver a water order.
  • Conveyance losses vary from year to year, depending on demand for water and conditions including rainfall, soil condition, heat, wind and inflows from tributaries.
  • Low inflows and hot conditions will lead to higher than average losses.

More about losses in the River Murray

Menindee Lakes

  • Menindee Lakes water storage is owned and operated by New South Wales

  • The Murray–Darling Basin Agreement sets out the rules for the shared resources of the River Murray system, including Menindee Lakes.

  • The MDBA can only use the water in the Menindee lakes when volumes are high (above 640 GL) until they fall below 480 GL.

  • The MDBA cannot drain Menindee Lakes. Once the water level is low (below the 480 GL trigger point), New South Wales manages the water to best meet local demands.

  • The lakes are in a semi-arid area and are shallow with a large surface area. In most years they lose the equivalent of one Sydney Harbour of water to evaporation.

  • When there is more water in the Menindee Lakes (total storage volume is 1,731 GL), they may lose up to up to 700 GL a year in evaporation.

More about managing Menindee Lakes

Flows to South Australia

  • New South Wales and Victoria need to share water with South Australia each year under the Murray─Darling Basin Agreement.
  • The most South Australia can receive as an entitlement is 1850 gigalitres each year, but flows to South Australia can be much higher during flood.
  • The South Australian government has to use some of its entitlement to run the river in the same way other states do.
  • On its way to South Australia, water provides important recreational and environmental benefits to communities along the river.

Why the river needs to connect to the sea

  • It is important that the river reaches the sea to flush sediments and salt out of the system.
  • There is currently not enough water flowing to the end of the river system to maintain the health of the Lower Lakes and Coorong.
  • By reducing seawater inflows, barrages near the Murray Mouth protect the Lower Lakes from becoming too saline.
  • High salinity reduces water quality and would permanently damage the lakes, the Coorong and the upstream river environment.

More about flows to the lower Murray–Darling Basin

Sharing River Murray Water

  • New South Wales, Victoria and South Australia have a long-standing agreement to share the water of the River Murray and the rivers that flow into it.  
  • The Murray–Darling Basin Agreement specifies how the water is shared. States decide how to allocate their share of water to entitlement or license holders such as farmers.  
  • The MDBA delivers water in the River Murray System on behalf of the states and has no involvement in setting entitlements or allocations.  
  • States own the water in the system and provide entitlements, or licences to water users. 
  • All water entitlements have the same conditions of use – the rules are the same for individuals, businesses and environmental water holders. 
  • The amount of water allocated by states depends on how much water is available and the type of entitlement held. 
  • Entitlements are permanent rights to water and allocations are the amount of water you get against that entitlement from year to year. 
  • Entitlements and allocations can be bought and sold on the water market. Entitlements to reliable water cost more to buy, entitlements or licenses with less reliable water are cheaper. 

More about sharing the water

Updated: 19 Nov 2019