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How water is shared between the states

The River Murray supports one of Australia’s largest agricultural regions, is home to many unique Australian plants and animals and is the lifeblood for many towns and communities.

The climate in Australia is highly variable and conditions differ from year to year and across regions.

Managing the water resources in the Murray-Darling Basin is complex and involves close cooperation and collaboration between the Australian Government, the governments of South Australia, Victoria, New South Wales, Queensland and the Australian Capital Territory (ACT), as well as other state and basin-wide authorities.

Sustainable diversion limits (SDLs) limit how much water can be taken for consumptive water use to ensure that there is enough water available to maintain a healthy river system. The River Murray is a highly regulated system with locks, weirs and dams in place to allow careful management of the river and to help meet the needs of towns, communities and food producers.

Water is shared between New South Wales, Victoria and South Australia according to rules set out in the Murray-Darling Basin Agreement, which is part of the Water Act 2007.

This video shows how water from the River Murray is shared and how the Murray-Darling Basin Authority operates the river.

The Murray-Darling Basin Authority operates the river according to these rules on behalf of Basin Governments.

Before any water can be allocated for use, the agreement requires states/ACT to keep water in reserve for critical human needs, which helps safeguard water for communities in times of drought. There are also river system demands and needs that must be met, with the priority being the water needed to keep the system running.

Once these needs have been met, the Murray Darling Basin Authority is responsible for determining the total water each state/ACT will have available to allocate to individual water entitlement holders. This is based on a range of important factors including the volumes of water held in major storages, water quality and projected climatic conditions. 

Once water is provided to each state/ACT, the states/ACT then allocate water to entitlement holders in accordance with local water sharing plans. In South Australia, these are known as water allocation plans.

Water is allocated differently in each state/ACT because each has its own management approach to suit the needs of local communities, food producers, industries and the environment. This means that each state/ACT has unique water entitlement products and different rules and requirements about how and when water is allocated. South Australia prioritises allocations against entitlements compared to making water available for carryover.  

Each state has its own water sharing arrangements.  For New South Wales this can be found on the Department of Planning, Industry and Environment website and for Victoria on the Northern Victoria Resource Manager website. Current River Murray water allocations in South Australia, NSW and Victoria are included in the table below. 

State Valley
SA Murray NSW Murray Victorian Murray
15 October 2019[i] 15 October 2019[ii] 15 October 2019[iii]
Entitlements on issue* (GL) Percent Allocation Current Volume Available (GL) Entitlements on issue* (GL) Percent Allocation Current Volume Available (GL) Entitlements on issue* (GL) Percent Allocation Current Volume Available (GL)
Town water supply / CHWN 154 100% 154 58 100% 58 77 100% 77
High Security Allocations 630 87% 548 190 97% 184 1,245 40% 498
General/Low Security Allocations 0 1,674 0% 0 311 0% 0
Carryover 102 avg. 18% 300 avg. 40% 579
Total 784 702 1922 542 1633 1154

[i] https://www.environment.sa.gov.au/files/sharedassets/public/water/rm_allocations/190902-rm-water-allocation-announcement.pdf

[ii] https://www.industry.nsw.gov.au/__data/assets/pdf_file/0020/272342/WAS-murray-190902.pdf

[iii] https://nvrm.net.au/seasonal-determinations/current

To find out more about how water is shared between the states visit the Murray-Darling Basin Authority website. View water resource availability to find out about current conditions and how much water is available.

How water is allocated across South Australia

In total, South Australia has an annual Entitlement of 1,850 GL under the Murray-Darling Basin Agreement.

Whilst full Entitlement is available at the start of most water years, in dry years it may be reduced.  In these years, South Australia receives a share of the available resources. 

In 1969, the South Australian Government capped extractions from the River Murray.  In 1997 a Cap on diversions was implemented across many of the Basin’s river valleys and Sustainable Diversion Limits are now in place across the whole Basin.  

As with other states, not all of South Australia’s Entitlement is allocated for the purpose of consuming water to ensure that there is enough water for river health. 

Once the volume of water available is known, water is allocated to water users in accordance with our state's water allocation plan. South Australia has developed the River Murray Water Allocation Plan in collaboration with the local community and key stakeholders and this outlines the state’s water sharing rules. The River Murray Water Allocation Plan has been updated in 2019, to make sure it is compliant with the requirements of the Basin Plan.

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