Flows in the River Murray system

At any given time, water flowing through the river is destined for various uses, including irrigation, industry, communities, the environment, and meeting South Australia’s flow entitlement. The exact mix of these flow components is determined by demand and water availability, amongst other factors.

The graphic below is indicative of how water flow is managed throughout the seasons across a typical year.

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* including meeting South Australia's flow entitlement.

Water for the environment

Overall, water for the environment is a small percentage of the total water used in the Murray–Darling Basin. Across the past 5 years the volume of water for the environment used under water entitlements has averaged 18% of the total water used in the Basin.

Importantly, water held for the environment uses the same entitlement framework as consumptive users. In any given year the amount of water available for delivery to key environmental sites is determined based on the same rules that apply to all other consumptive water uses.

Types of water for the environment

Water for the environment can be categorised as:

• 'Planned' environmental water – water that flows through the river system that is typically managed through rules outlined in state water resource plans and is used to improve the health of the environment.
• 'Held' environmental water – is water that is held by government agencies and is delivered where and when it is needed in the river system. It is water that is allocated to relevant government agencies through water licenses for environmental use.

Sharing River Murray water

For more than 100 years, the states have been sharing the waters of the Murray. The Murray–Darling Basin Agreement sets out the rules negotiated and agreed by New South Wales, South Australia, Victoria and the Australian Government.

The Murray–Darling Basin Authority (MDBA) facilitates the sharing of River Murray water based on the agreed rules. The MDBA determines releases in the River Murray System to meet expected demands from the states. A range of scenarios are considered and these are used to guide operations for the year. As the year unfolds the scenarios and options are updated and operations amended accordingly.

Identifying how much water is available to the states takes into consideration stored water and seasonal weather conditions. Of the available water the MDBA determines conveyance water, critical human water needs and reserve for the next season before it shares water to the states. Each state has developed its own set of entitlement licences and rules around how to allocate their share of water. This means allocations, water orders and delivery of water all work in a different way from state to state.