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The determination to adjust sustainable diversion limits

The Basin Plan sets sustainable diversion limits, which is how much water can be used in the Murray–Darling Basin, while leaving enough to sustain natural ecosystems.

To provide flexibility, the Basin Plan includes a mechanism to adjust sustainable diversion limits. The Adjustment Mechanism works in two parts – the package of supply projects aims to achieve the equivalent environmental outcomes with less water. This means that more water can remain in the system for other users, including households, industry and irrigated agriculture. Efficiency projects are activities that change water use and save water for the environment.

Sustainable diversion limit adjustment determination

It has been agreed the same Basin Plan environmental outcomes can be reached with less water, meaning there will be 605 gigalitres (GL) additional water available for communities through the Adjustment Mechanism and the package of supply projects.

The recommendation to adjust sustainable diversion limits, through the Adjustment Mechanism, has been adopted by the Australian Parliament with bi-partisan support. The projects will move into the design and implementation phase and Basin state governments will work with local communities and affected landholders to consider local needs.

Each project is different and will be designed and implemented in customised ways. Some projects are already underway, while others are still in the early stages of design.

All Basin governments are committed to implementing both supply and efficiency projects between now and 2024. Projects will be regularly assessed and reported on and measures will be taken, to ensure environmental outcomes are achieved, as the projects progress.

The MDBA’s determination to adjust sustainable diversion limits

In October 2017, the Murray–Darling Basin Authority (MDBA) determined that a further 605 gigalitres (GL) of water, on average, would be available for consumptive use, if the suite of projects proposed by Basin state governments through the Adjustment Mechanism were implemented. Additional water for the environment would also be available through the efficiency projects, which will operate across the Basin through to 2024, subject to these projects having neutral social and economic impacts.

The Sustainable Diversion Limit Adjustment Mechanism: draft determination report outlines the MDBA’s recommended adjustment across the southern Basin and also at a catchment level.

The Basin Plan limits the amount that sustainable diversion limits can be adjusted. At the time of the determination, the Basin-wide sustainable diversion limit was 10,873 GL and this could be adjusted up or down by 5 per cent (approx. 543 GL).  

The assessment of supply projects has determined sustainable diversion limits can be adjusted up, so that 605 GL of water can remain available for communities. To ensure this water remains available for communities, a minimum of 62 GL of additional water savings through efficiency projects is required to pass the 5 per cent rule. The Sustainable Diversion Limit Adjustment Mechanism also requires efficiency measures to be progressively developed until 2024. 

The draft determination report also provides an overview of the Adjustment Mechanism and its role in the Basin Plan, the methodology developed to assess projects and a description of each of the projects nominated by Basin state governments.

Public feedback

The MDBA sought feedback from the public on the Sustainable Diversion Limit draft determination from 3 October to 3 November 2017. Throughout this period, 3,185 submissions were received. In September and October 2017 there were 29 public information sessions held, with over 700 people across the Basin attending one of these sessions. The MDBA welcomed this substantial contribution and recognises the feedback will be important in designing, implementing and evaluating supply projects. 

The MDBA’s Summary of Feedback report outlines comments from both the face-to-face sessions and written submissions received, as well as recommendations for the design and implementation of the projects. This feedback has been used to make a recommendation to the Australian Government Minister responsible for water and will also inform the next stages of design, implementation and evaluation of the projects.

Revisions to the Draft Determination

No new information or evidence was put forward during the public comment period to change the MDBA’s conclusion on the determination of the adjustment volume.

In the MDBA’s Draft Determination, the 5 per cent limit on the proposed adjustment was considered to be 544 GL. To remain in line with the 5 per cent limit outlined in the Basin Plan, this number was revised to 543 GL in the final determination provided to the Australian Government Minister responsible for water. The 5 per cent rule is explained in detail in the Summary of Feedback report.

Updated: 09 Dec 2019