Sustainable diversion limit adjustment mechanism – reports and business cases

This report highlights the issues and opportunities raised by stakeholders on the sustainable diversion limit adjustment mechanism and the package of projects. The MDBA has provided recommendations on the issues and opportunities raised during consultations and the public comment period.

Outlines a model of a fully implemented Basin Plan. The report describes how changes included to the Basin Plan benchmark scenario to produce the sustainable diversion limit benchmark scenario. This represents the implementation of the Basin Plan to achieve 2,750 GL of water recovery for the environment. This model was agreed to by all Basin governments.

This report describes the implementation of the supply measures package in the modelling framework. It explains how the model represents and assesses the supply measures to achieve maximum supply contribution. The report lists the results of 3 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.

The report 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.

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 Basin Officials Committee 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.

The MDBA has developed and trialled the way it will assess projects under the Basin Plan's sustainable diversion limits adjustment mechanism in 2016. The framework explains the key concepts, how the sustainable adjustment limit adjustment mechanism works, and results for trialling the method using 7 of the 27 supply projects submitted by Basin State governments for this purpose. The framework includes the use on an independently developed (by the Commonwealth Scientific and Industrial Research Organisation), scientifically robust scoring method (test) for environmental equivalence. An independent review panel has found the framework and test to be fit for purpose.