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Water in the Murray–Darling Basin has to be managed to make it safe, deliver it to the people who need it, and to protect the future of the river system. This guide will help you understand what water management is, how water in the Murray–Darling Basin is managed, and who’s responsible for what.

Reading time: 15 mins


  • Why water in the Murray–Darling Basin needs to be managed

  • The challenges of managing water in the Basin

  • What water management is

  • Who is responsible for what

  • About water management activities

  • About water management for the future

Why water in the Murray–Darling Basin needs to be managed

Water in the Basin must be managed to sustain the river system and maintain water quality. Water management means that water is safe and can continue to support local communities, businesses and industries, Australian agriculture, and unique ecosystems.

When water is well managed it is:

  • safe for humans to drink
  • safe for other uses such as farming and recreation
  • used sustainably
  • delivered to where it needs to go
  • shared fairly between those who need it, including the environment.

Water management constantly adapts in response to the latest scientific research and new information.

There are many demands on water in the Murray–Darling Basin. Since European settlement, people have dramatically changed the land, using it for farming and mining, and building cities, towns and roads.

We use far more water than we used to even a few decades ago. But the amount of water that comes from rain or groundwater hasn’t increased with us – in fact, due to climate change, it has decreased.

A graphic showing the increase of water use since the River Murray Agreement was signed in 1914. It shows that without water management the growth in water use would have continued to rise and shows that since water management reforms were introduced we h

There are particular challenges in managing water in the Murray–Darling Basin

  • The Basin covers 4 states and a territory. So, people in New South Wales rely on water flowing in from Queensland, and people in South Australia rely on water flowing from New South Wales.
  • There are also many different types of ecosystems throughout the Basin. Some of them (like wetlands) need more water to survive than others (such as semi-arid deserts).

The Murray–Darling Basin Authority (MDBA) was established to manage the Basin as a connected system because not enough water was making its way through the system to fulfil the needs of users downstream, and because the Australian government recognised that communities and the environment need water as well as farmers and irrigators if the system is going to be sustainable for future generations.

Limits are set on the amount of water that can be used in any one place to make sure there is enough water left in the river to flow downstream and to protect the Basin’s unique ecosystems.

An overview of water management

To the MDBA and the organisations it works with, ‘water management’ means the work that needs to be done to make water safe and get it to those who need it.

Water management includes:

  • dividing water fairly and sustainably by calculating water availability and allocating water to entitlement holders within the limits
  • making sure water gets where it needs to go so that human and environmental needs are met through river operations, including storing water for future needs and delivering water
  • making sure water is safe for people, plants and animals by monitoring, evaluating and maintaining water quality
  • making sure the water market is fair by developing, complying with and enforcing water trading rules
  • making sure the river system is as healthy as possible by allocating water for the environment.

All water management activities require careful planning based on science and research. River operators make daily decisions based on the best available science, monitoring and modelling to manage the waters of the river.

You can read more about how these different aspects of water management work in the Murray–Darling Basin in section 4 of this guide.

Water management means making sure the right amount of water makes it to the right place at the right time so that it can be used by those who need it.

Who is responsible for managing water

Responsibility for managing water in the Murray–Darling Basin is shared between the Basin governments and partners, including the:

  • Murray–Darling Basin Authority
  • New South Wales Government
  • Queensland Government
  • South Australian Government
  • Victorian Government
  • Australian Capital Territory Government
  • Australian Government Department of Climate Change, Energy, the Environment and Water
  • Commonwealth Environmental Water Office.

How responsibilities are divided

The MDBA was established to manage the Basin as a connected system. The MDBA is responsible for:

  • coordinating how the Basin’s water resources are managed, considering the health of the Basin as a whole
  • calculating how much water is in the River Murray system and informing New South Wales, Victoria and South Australia of their ‘share’
  • delivering water to entitlement holders in the River Murray system
  • managing water in most of the River Murray system
  • maintaining water infrastructure in the River Murray system
  • implementing the Murray–Darling Basin Plan.

The states have agencies and authorities to manage water in their states. Their responsibilities include:

  • allocating water to entitlement holders
  • managing water that isn’t managed by the MDBA
  • maintaining dams and water storages outside the River Murray system
  • developing formal plans about how they will manage water to help them comply with the Murray–Darling Basin Plan.

Some responsibilities are shared between the MDBA and the states such as:

  • delivering water to entitlement holders
  • monitoring and maintaining water quality
  • making decisions about water for the environment.

The Commonwealth Environmental Water Office was created to manage water for the environment. The Commonwealth Environmental Water Holder is responsible for:

The Australian Government Department of Climate Change, Energy, the Environment and Water is responsible for:

  • buying water from entitlement holders and investing in more efficient irrigation so there is more water available in the system to keep rivers, lakes and wetlands healthy. This is called ‘recovering water’.

The Inspector-General of Water Compliance is responsible for:

How the MDBA and the states work together

The MDBA and Basin state governments regularly discuss current issues and operations.

The MDBA’s processes are reviewed by Basin state governments, who provide feedback on the MDBA’s operating approach. A group of independent experts also reviews river operations each year.

This approach to working together means the MDBA and the Basin states:

  • reach consensus on major decisions
  • balance competing requirements
  • find ways to improve operations and adapt to changing conditions.

Each state government has a body that is responsible for managing water in the Basin, working together with the MDBA. Some are state-owned, while others are statutory corporations which have been nominated by the state. These bodies are:

Different approaches to water management in the northern and southern Basins

The northern and southern Basins have very different climates and landscapes.

In the southern Basin, the natural highs and lows of the land make it easier to store water and release it in a controlled way, so that it gets to people and places when they need it. There is generally more rain in the southern Basin, so more reliable predictions can be made about future water availability.

The northern Basin is mainly flat, with few hills or mountain ranges. This means that there are fewer low points in the land where water naturally collects in rivers or lakes. The water in the northern Basin moves slowly, in wide, shallow rivers and evaporates more quickly. As well, there are fewer places to store large amounts of water. All these factors mean that water in the northern Basin is regulated and managed differently to that in the southern Basin.

The boundary of the Murray–Darling Basin, including the boundaries of the northern and southern basins.
The boundary of the Murray–Darling Basin, including the boundaries of the northern and southern basins.

Water management activities

Water in the Murray–Darling Basin is managed to improve the overall health and connectedness of the system.

The activities involved in water management respond to changing conditions and the needs of different catchments and states.

Calculating water availability and allocating water

Water in the Murray–Darling Basin is allocated to water entitlement holders. Water management includes calculating how much water is available for human consumption, the environment and industry so water can safely be taken from the river.

Each state has its own rules on how entitlements and allocations work. This is because the environment, agriculture, population and rainfall differ from state to state, and so the demand for water also varies from one location to another.

Who does what

The MDBA is responsible for calculating each state’s share of water in the River Murray system.

State governments allocate water within each water catchment, depending on how much water is available. The MDBA is not involved in deciding on the amount of water to allocate to entitlement holders.

River operations including delivering water

In the Murray–Darling Basin, water is held in lakes or dams (‘storages’) throughout the Basin. There is other infrastructure in the river system, including weirs and locks. River operators use this infrastructure to release water from those storages depending on when and where it is needed. River operators release water based on water orders placed by entitlement-holders.

To get the right amount of water to where it needs to go, river operators:

  • calculate the amount of water that will be lost to evaporation and soil absorption as water moves through the system
  • calculate how much water will enter the system from tributaries, rainfall and groundwater (to minimise floods and spills)
  • factor in the time it takes for water to move from storages to the different entitlement holders along the system.

Who does what

The MDBA operates the River Murray up to the border of South Australia and the Menindee Lakes.

State governments or their nominated bodies are responsible for delivering water, except in the River Murray system, which is operated by the MDBA.

The states are responsible for managing water in all the parts of the Murray–Darling Basin that aren’t managed by the MDBA.

A map showing who operates which parts of the Basin

Monitoring and maintaining water quality

Water quality can be affected by many different environmental factors and weather events. Algal blooms, blackwater events, acid sulfate soil and salinity can all make water less safe for humans, plants and animals.

Who does what

The MDBA isn’t responsible for maintaining water quality, but it can sometimes help by releasing water to dilute saline or acidic water, or to try to prevent blackwater events and fish deaths.

The MDBA also monitors water quality in the River Murray system. Water samples are regularly collected from 28 sites along the River Murray and its tributaries in New South Wales, South Australia and Victoria. The data recorded from these sites includes:

  • levels of chemicals and organisms in the water
  • acidity
  • temperature
  • turbidity.

This data helps the MDBA:

  • assess how human activity is affecting the river
  • identify sources of pollution
  • respond to algal blooms and blackwater events
  • make decisions about when to release water
  • make decisions about how to improve water quality
  • keep long-term records.

The MDBA also manages salt interception schemes along the River Murray, which help prevent too much salt from entering the rivers.

State governments, in partnership with the Australian Government, are responsible for maintaining water quality. Depending on the location and circumstances, ways of managing water quality include:

  • releasing water to dilute saline or acidic water
  • installing water aerators or releasing extra water in areas where water is low in oxygen
  • treating water to combat algal blooms
  • installing and maintaining salt interception schemes to prevent too much salt from entering rivers.

Water trading rules

Water entitlement holders can sell or buy some or all of their water by trading on the water market. Water can be bought and sold permanently or temporarily.

For example, a rice farmer may choose not to plant crops in a dry year and temporarily sell their water allocation to someone who wants it, like an almond farmer whose trees need water every year. Alternatively, a farmer may decide their farm is no longer viable and may decide to permanently sell their water entitlement to an environmental water holder.

Rules for water trading are different in different places. Prices can also vary across regions and for different types of water rights. The price of water reflects supply and demand and can change over time.

Who does what

The MDBA’s role is to facilitate fair, consistent and transparent water trade across the Murray–Darling system. The MDBA:

  • provides information on water trading
  • works with Basin state governments to ensure their rules comply with the Murray–Darling Basin Plan's trading rules
  • oversees the Basin states’ compliance with their water resource plans
  • checks whether the Basin states have only used water in the amounts and ways they said they would and can take action if they haven’t.

State governments create most of the rules about water trade in the Basin. They are responsible for making sure individual entitlement holders:

  • comply with the rules
  • take only the water that is allocated to them
  • use water in the way(s) their entitlements or licenses stipulate.

Environmental water holders can buy water on behalf of the Australian or state governments and can use this water to improve the health of natural ecosystems in the Murray–Darling Basin.

State water resource plans

By agreeing to the Basin Plan, all Basin states have made a commitment to developing and improving sustainable water practices. Water resource plans are developed by each state government to set out how it intends to use its share of water to comply with the rules in the Basin Plan.

The Basin Plan specifies that the rivers of the Basin must be managed as a connected system. This includes the tributaries flowing into the main rivers. States’ water resource plans must address specific requirements on connectivity, including identifying the connections for that particular catchment, and setting out how these connections will be managed.

The plans specify:

  • how water will be used at a local level
  • new limits on the amount of water that can be taken from the system
  • the amount of water allocated to the environment
  • how water quality standards can be met.

Each state government is responsible for complying with their water resource plans and accounting for the water that is taken from the system.

Water resource plans are a requirement under the Basin Plan and must be submitted to the MDBA. The MDBA makes sure the states comply with their water resource plans and checks entitlement holders are taking only the water that has been allocated to them.

Water for the environment

A landscape of trees in drought at Wallpolla State Forest

Water for the environment’ is used to improve the health of rivers, wetlands and floodplains. Water is allocated to federal and state environmental water holders across the Basin, who make decisions about when, where and how much water is released for the environment.

Who does what

The MDBA works with scientists and local groups to understand the environmental needs of specific areas of the river and its surroundings to decide where and when water should be released.

The MDBA also gives advice and guidance to environmental water holders about whether any water should be released, and, if so, where it will have the best environmental outcome.

State governments plan and implement environmental watering on a local level. State environmental water holders decide if, where and when water for the environment should be delivered within their state, based on information provided by the MDBA and other environmental bodies.

The Commonwealth Environmental Water Holder (CEWH) is responsible for planning and implementing environmental watering across the Basin. This body makes decisions about:

  • using the water to meet identified environmental demands through the Water Use Framework
  • keeping the water for use in the next water year through carryover arrangements
  • selling or buying water for equal or greater environmental benefit through the Water Trading Framework.

The Commonwealth Environmental Water Holder’s decisions are guided by the Basin Plan, and the environmental watering strategy is part of a long-term plan to improve the overall health of the Basin.

Planning for the future: Sharing responsibilities under the Basin Plan

The Murray–Darling Basin Plan was created to improve the health of the Basin so that future generations can be sustained by its resources. It sets out how the MDBA and the states should work together.

The way water is managed changes over time

Water management is an evolving process. The way water is managed in the Basin has changed greatly over the past century, and will continue to change in the future. Climate change, the demand for water and the changing health of the environment will all influence how water is managed.

There is a continual cycle of planning, managing, monitoring and evaluating so that water is always managed in the best way possible and changes can be made.

Regular monitoring and evaluation includes consulting with communities, industry experts and partner governments.

Working together for sustainable future

Building a sustainable future is everyone’s responsibility. The MDBA and state and federal governments work together to set goals and meet them using water sharing plans and water resource plans.