Sustainable diversion limit adjustment mechanism

The Basin Plan is a flexible and adaptive plan that balances the needs of Basin communities and the environment, to achieve a healthy and productive river system. Under the Plan, there are a range of changes that can be made to help the environment and achieve Basin Plan outcomes.

The Basin Plan

View a short video that explains the Basin Plan.

The sustainable diversion limit adjustment mechanism

View a short video on what it is and how it works.

The Basin Plan sets Sustainable Diversion Limits (SDLs), or how much water can be used in the Murray-Darling Basin, while leaving enough water for the environment.

To provide flexibility, the Plan includes a mechanism to adjust the Sustainable Diversion Limits. If environmental outcomes can be reached with less water, more water can remain in the system for other users, including irrigated agriculture.

Improvements can be made to save water through water supply infrastructure and changes to river operating rules and on-farm efficiency. These changes can benefit the environment by using water more effectively to achieve the outcomes of the Basin Plan. 

There is a suite of projects which make the delivery of water more efficient and flexible. Through these projects, the amount of water that needs to be recovered for the environment will be reduced, returning in excess of 600 gigalitres (GL) of water back to households, industry and farming.   

Over the coming months, the MDBA will continue to analyse the package of projects to develop a final SDL adjustment figure.

SDL adjustment mechanism timing

The Murray-Darling Basin Ministerial Committee endorsed the package of SDL adjustment projects on 16 June 2017.  

Identifying the projects is just the start of this process. There are years of work ahead to finalise the design of the projects and implement them.

Below is a summary of the stages in the SDL adjustment mechanism process.

summary of stages in SDL adjustment mechanism process
Stages in SDL adjustment mechanism process


Assessment and methodology

The Murray–Darling Basin Authority (MDBA) has developed an assessment framework, to assess how much water is being saved through the SDL Adjustment Mechanism projects, to calculate the new recovery target. This framework has been trialled and thoroughly reviewed by independent experts and all Basin governments. It is scientifically rigorous and suitable for the adjustment.

The assessment framework compares project outcomes with the Basin Plan and applies tests during the comparison to ensure the benefits of the Basin Plan are protected.

The assessment framework includes components such as computer (hydrological) models, hydrological indicator sites, ecological elements and ecological equivalence scoring.

Roles and responsibilities

Over the coming months, the MDBA will be focusing on assessing the projects, calculating and proposing the SDL adjustments.

Basin state governments are responsible for delivering the projects at a local-level, including consulting with communities and detailed project design and implementation.  

The MDBA will ensure the integrity of the SDL adjustment mechanism in delivering environmental outcomes by regularly reporting progress in implementation.

SDL adjustment mechanism projects are funded by the Australian Government.