On 5 June 2013, the Intergovernmental Agreement on Implementing Water Reform in the Murray Darling Basin (the IGA) came into effect. The IGA, between Commonwealth and states, builds on the 2008 Intergovernmental Agreement and supports the objectives of the Murray-Darling Basin Plan (the Basin Plan), which passed through the Commonwealth Parliament in November 2012.
On 29 May 2015, the Murray-Darling Basin Ministerial Council (the Ministerial Council) agreed to amend Schedule 1 of the IGA (Protocol for consideration of surface water sustainable diversion limit (SDL) adjustment measures) to reflect revised assessment timeframes for the SDL adjustment measures and constraints measures.
On 27 November 2015, the Ministerial Council agreed to further amendments to Schedule 1. These amendments establish an alternative assessment timeline for a small number of complex and highly prospective supply and constraint measure projects.
On 18 November 2016, the Ministerial Council agreed to further amendments to Schedule 1. These reflect amendments to the Basin Plan made by the Water Legislation Amendment (Sustainable Diversion Limit Adjustment) Act 2016 that allows for a second notification of SDL adjustment measures by 30 June 2017 to maximise the benefits of the SDL adjustment mechanism. Ministers also agreed to further revisions to timeframes for development and assessment of projects under the SDL adjustment mechanism.
On 17 March 2017, the Ministerial Council agreed further changes to the timeframes for development and assessment of SDL adjustment measures. The revised timelines reflect recognition by the Basin Officials Committee that many of the proposed measures are complex and require additional time for assessment to resolve outstanding business case issues.
On 4 August 2019, the Ministerial Council endorsed amendments to the IGA relating to the implementation of measures to improve environmental outcomes in the northern Murray–Darling Basin. Basin Leaders signed the amendments on 9 August 2019.