Sustainable diversion limits

When the Basin Plan was implemented in 2012, the sustainable diversion limit or SDL was set at 10,873 GL. This is the amount of water that can be used by people from rivers in the Murray–Darling Basin. This figure was agreed upon by all Basin States.

Balancing the water needs of communities, industries and the environment is key to achieving a healthy working Basin. Sustainable diversion limits set an environmentally sustainable level of water use.

What is the adjustment mechanism?

The sustainable diversion limit (SDL) adjustment mechanism is a process that Basin States agreed on, that could change the volume of water recovery set under the Murray-Darling Basin Plan.

Through this process, we are trying to find smarter ways of running the river system, while making sure we have a healthy working Basin.

During the development of the Basin Plan prior to 2012, Basin water ministers requested that there be an arrangement in place specific to the Southern Basin, to provide flexibility with water recovery. This arrangement is the SDL adjustment mechanism.

When the Basin Plan was implemented in 2012, the sustainable diversion limit or SDL was set at 10,873 GL. This is the amount of water that can be used by people from rivers in the Murray–Darling Basin. This figure was agreed upon by all Basin States.

To reach this SDL figure, we have to return 2,750 GL of water to the river system to ensure a sustainable future for generations to come. The 2,750 GL is known as the water recovery target.

To reach that target, the southern basin had to contribute 2,289 GL, of which 1,682 GL has now been recovered. The water we still need to recover in the southern basin is 607 GL.

The remainder of the water recovery target will come from the northern basin, and this is being addressed through the Northern Basin Review.

Under the Plan, the SDL adjustment mechanism could lead to a change to the water recovery target up or down by 5%.

This change is based on a series of new state projects that use water more efficiently, allowing for saved water to be returned back to irrigation or environmental use.

State projects

Over the last few years, Basin state governments have been putting forward new projects that look at smarter river management practices and the more efficient and effective use of water.

There are three types of projects:

  1. River system projects that change the way the system is managed to achieve equivalent environmental outcomes using less water (eg reconfiguring suitable lakes or storage systems to reduce evaporation).
  2. Water efficiency projects that provide more water for the environment through efficient use of irrigation water (eg lining channels to reduce water loss within the irrigation network).
  3. Projects that make changes to physical structures or river management practices so we can better deliver environmental water.

Australian Government funding is available for efficiency projects that achieve the same or better social and economic outcomes.

Take a look at the list of the projects which have been proposed by Basin governments. For more information about projects in your area, please contact your state water agency.

State governments have until 30 June 2017 to put forward projects and have committed to consulting with their Basin communities.

The MDBA will calculate the amount of change to the SDL from the package of proposals agreed by the states.

What is the 450GL ‘up water’ and 650 GL ‘down water’?

In the Basin Plan, it notes that some governments anticipated that by using environmental water more efficiently, the new river system projects would allow for the water recovery target to be reduced by 650 GL.

However, that figure is greater than the 5% outlined in the Plan.

Alternatively, the Plan also outlined that by using water efficiency projects, we could get an additional 450 GL of water for the environment – as long as the result had the same or better social and economic outcome.

So this means that the water recovery target can’t go down by the full 650 GL amount, without some movement ‘up’ as well.

Making a change to the SDL

A draft determination, or any proposed changes to the SDL and water recovery target of 2750 GL will be available for public consultation in October 2017.

The MDBA will make a recommendation to the Federal Minister for Water, the Hon. Barnaby Joyce by 15 December 2017. A final decision will need to be tabled in Parliament.

The decision will come into effect as state Water Resource Plans are accredited and this process will continue until 2019.

Approved projects under the SDL adjustment mechanism process will be implemented from 2018 through to 2024.