The Sustainable Diversion Limit Adjustment Mechanism assessment – draft determination

The Sustainable Diversion Limit Adjustment Mechanism

The Basin Plan sets Sustainable Diversion Limits, which is how much water can be used in the Murray–Darling Basin, while leaving enough water for the environment.

To provide flexibility, the Basin Plan includes a mechanism to adjust Sustainable Diversion Limits. If Basin Plan environmental outcomes can be reached with less water, more water can remain in the system for other users, including households, industry and irrigated agriculture. Similarly, if farming practices can be made more efficient, more water can be made available for the environment.

The Sustainable Diversion Limit Adjustment Mechanism assessment – draft determination

The assessment has determined there will be 605 gigalitres (GL) additional water available for communities through the Adjustment Mechanism, if the package is agreed.

Adjusting Sustainable Diversion Limits is a key step in delivering the Basin Plan. The Murray–Darling Basin Authority (MDBA) has assessed a suite of projects, nominated by Basin state governments and determined the proposed adjustment to the Sustainable Diversion Limits.

The approach agreed by governments also includes efficiency projects, which allow more water to be made available for the environment by implementing projects that make farming practices more efficient. Up to 450 gigalitres is expected to be recovered between now and 2024, subject to these projects having neutral social and economic impacts.

This is just the start of the process. Basin state governments have until 2024 to implement the projects, and will work with communities, industry and experts on project design and implementation.

The Sustainable Diversion Limit Adjustment Mechanism: Draft Determination Report outlines the adjustment Basin-wide across the southern Basin and also at a catchment level. Subject to existing water recovery contracts being delivered, and the implementation of the Adjusment Mechanism efficiency component, this will mean no further water recovery in the southern Basin. It 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.

Read the report in full.

The method used to determine the proposed adjustment in each catchment results in a small over-recovery of water in some catchments – about 0.35 per cent of the Basin’s current Sustainable Diversion Limit. If the proposed Sustainable Diversion Limit Adjustment is approved, it is anticipated this water will provide flexibility for the implementation of the Adjustment Mechanism.

Table 2: Proposed SDL adjustments
SDL resource unit Water recovery target under the Basin Plan (GL) Proposed adjusted water recovery target (GL) Water recovery completed to 30 June 2017 (GL) Water recovery remaining after proposed adjustments (GL)
14 Murrumbidgee 563.0 401.0 401.0 0.0
15 New South Wales Murray 470.0 345.2 352.3 0.0
16 Lower Darling 15.0 15.0 20.0 0.0
17 Victorian Murray 455.4 382.6 397.0 0.0
18 Kiewa 1.3 0.0 0.0 0.0
19 Ovens 3.1 0.1 0.1 0.0
20 Goulburn 536.4 361.9 361.9 0.0
21 Broken 1.6 0.5 0.5 0.0
22 Campaspe 31.7 29.1 29.1 0.0
23 Loddon 22.8 11.9 11.9 0.0
25 South Australian Murray 181.9 131.8 143.9 0.0
27 Eastern Mount Lofty Ranges 1.9 0.0 0.0 0.0
29 Australian Capital Territory 4.9 4.9 4.9 0.0
Total 2289.0 1684.0 1722.6 0.0

Issues and opportunities that Basin governments have considered

Proposing the Sustainable Diversion Limit adjustment is just the start of this process.  

Governments have agreed to an adaptive approach that will allow projects to be further developed and implemented from 2018 until 2024. It is expected that projects will be refined as new information and innovations come to light.

As part of nominating the projects, Basin state governments have committed to involve communities, industries and experts in further designing and implementing the projects.

There are a range of themes incorporating both issues and opportunities that Basin governments have identified, either through community and stakeholder input or through research and analysis. This has shaped the projects and the design of the Sustainable Diversion Limit Adjustment Mechanism.

These themes have influenced Basin governments and some will be incorporated into implementation risk management.  The key themes relate to:

The Adjustment Mechanism in the Basin Plan

The Sustainable Diversion Limit Adjustment Mechanism package is made up of a suite of projects nominated by state governments for implementation in the southern Basin.

Through these projects, environmental outcomes will be achieved, but with less water. This means more water can remain in the system for other users, including households, industry and irrigated agriculture. The Adjustment Mechanism takes into account more efficient ways to deliver water for the environment, as well as more efficient ways to use water in industries and communities.

Read more about the issues and opportunities

Projects

There are three types of projects that make up the Sustainable Diversion Limit Adjustment Mechanism:

  • Supply projects are improved ways to manage the Basin's rivers to more efficiently deliver water for the environment. Projects include environmental works and changes to river operating rules, which achieve environmental outcomes, with less water.
  • Efficiency projects make water delivery systems more effective. This can include replacing or upgrading on-farm irrigation, or lining channels to reduce water losses within an irrigation network. Basin governments are evaluating ways in which up to 450 gigalitres may be secured for the environment through programs that improve the efficiency of water use between now and 2024. Governments have also commissioned a review of how to best design, target and resource efficiency measures to provide additional water for the environment. The review, conducted by EY, will report in December 2017.
  • Constraints projects involve removing constraints on rivers to better deliver water and can include changes to physical features such as crossings and bridges. They can also change river practices and rules.

Read more about the issues and opportunities

Assessment method

The MDBA administered the assessment framework, designed in collaboration with Basin governments, to assess the state projects and calculate how much water these projects could contribute towards any change in Sustainable Diversion Limits. The methodology to assess the projects has been agreed by Basin governments. 

Read more about the issues and opportunities

Communication and consultation

The determination is one part of a broader plan to manage the system as a whole for Australia. When the Basin Plan was established, it was acknowledged that adjustments to Sustainable Diversion Limits may be needed – this is why the Adjustment Mechanism was built into the plan to provide this flexibility.

Proposing the adjustment is just the start of this process. Governments have agreed to adaptively manage the projects during implementation from 2018-2024. Basin state governments will involve a wide range of people including communities, industries and engineers in the design and implementation of the projects.

Community feedback was provided during September information sessions in the southern Basin and any further feedback on individual projects will be provided to Basin state governments.

Read more about the issues and opportunities

Need more information

During October, the MDBA is hosting online information sessions, about the Sustainable Diversion Limit Adjustment Mechanism and particularly the MDBA assessment. These sessions will include a short presentation on information in the assessment report and there will be an opportunity to ask questions. Register your interest for the online sessions.

    For more information on the Sustainable Diversion Limit Adjustment Mechanism projects contact the relevant state water authority:

    Basin governments held information sessions in the southern Basin during September to advise on progress of the Sustainable Diversion Limit Adjustment Mechanism and the process that will be followed over the coming months.  

      Providing feedback

      The Sustainable Diversion Limit assessment is available for public comment from 3 October–3 November 2017.

      Basin governments are aware of a range of issues and opportunities and plan to incorporate these into implementation activities over the coming years. 

      The public is invited to provide feedback on any issues or opportunities that Basin governments are not already aware of. This is also an opportunity to provide information that can inform and strengthen the implementation of the Sustainable Diversion Limit Adjustment Mechanism projects. Provide feedback now.

      How feedback will be used

      Feedback provided on the Sustainable Diversion Limit Adjustment Mechanism will be used to provide advice, along with the Sustainable Diversion Limit assessment, to the Commonwealth minister responsible for water.

      Project specific feedback will also be provided to Basin state governments to contribute towards strengthening the design and implementation of Sustainable Diversion Limit Adjustment Mechanism projects.

      Once the Minister has considered the Sustainable Diversion Limit assessment and a decision has been made, the proposed change to the Sustainable Diversion Limit will be tabled in Parliament.

      Key documents

      Sustainable Diversion Limit Adjustment Mechanism - Draft Determination

      The MDBA has assessed a suite of projects to determine an adjustment to the Sustainable Diversion Limits. The following report outlines how the MDBA has administered the assessment framework, designed in collaboration with Basin governments, to assess the state projects and calculate how much water these projects will contribute towards any change in SDLs.

      Benchmark conditions of development for assessment of the SDL supply contribution

      The Benchmark outlines a model of a fully implemented Basin Plan. The report describes how changes were included into the Basin Plan Benchmark scenario to produce the Sustainable Diversion Limit Benchmark scenario. This represents the implementation of the Basin Plan to achieve 2750 GL of water recovery for the environment. This model was agreed to by all Basin governments.

      Modelling assessment to determine SDL Adjustment Volume

      The Modelling Assessment report describes the implementation of the supply measures package in the modelling framework. The report explains how the model represents and assesses the supply measures to achieve maximum supply contribution. The report lists the results of three equivalence tests (ecological elements score tests, limits of change in environmental outcomes, and reliability of supply targets) to compare environmental outcomes and reliability of the Sustainable Diversion Limit Adjustment scenario to the Sustainable Diversion Limit Benchmark scenario. 

      Independent Review of Hydrologic Modelling for SDL Adjustment (by Bewsher Consulting)

      The Independent Audit of Modelling report details the findings of the independent review of the Sustainable Diversion Limit Benchmark and Adjustment scenarios. It gives a detailed evaluation of the modelling framework, outlining the methodology and criteria used to assess the Sustainable Diversion Limit Benchmark and Adjustment scenarios. The independent audit lists a number of suggested improvements to ensure the modelling framework is an appropriate representation of the system and remains fit for purpose. 

      Independent Expert Panel Murray–Darling Basin Plan SDL Limits of Change Review

      Prior to the Sustainable Diversion Limit adjustment determination, early MDBA modelling indicated the potential for a number of limits of change rules to breach. The MDBA commissioned an expert review panel to undertake an independent ecological analysis of the potential breaches likely to occur across several possible Sustainable Diversion Limit adjustment model runs. This report outlines the independent expert panel's assessment.

      The SDL adjustment assessment framework for supply measures

      The MDBA has developed and trialled the way the assessment framework will assess projects under the Basin Plan's Sustainable Diversion Limits Adjustment Mechanism in 2016. The framework brochure explains the key concepts, how the Sustainable Diversion Limit Adjustment Mechanism assessment works, and results from trialling the method using just seven of the supply projects submitted by Basin state governments in 2016 for the purpose. The framework includes the use of an independently-developed (by the CSIRO), scientifically-robust scoring method (test) for environmental equivalence. An Independent Review Panel has found the framework and test to be fit-for-purpose.

      Advice from the Basin Officials Committee

      The Basin Officials Committee has reviewed the draft determination and provided its advice to the MDBA on the proposed adjustment to Sustainable Diversion Limits. This includes advice from the New South Wales, Victorian and South Australian governments.