As part of the implementation of the Basin Plan, the Murray-Darling Basin Authority (MDBA) has put forward a strategy to manage constraints. In the context of the Basin Plan, a constraint is any rule or structure which limits the volume or timing of the delivery of environmental water. Constraints can include physical structures, river management practices, and operational limits to river heights.
Work completed by the MDBA has shown that while easing constraints will not independently lead to the recovery of additional water, it will allow better outcomes to be achieved through the use of environmental water. This contributes to greater efficiency in the use of environmental water, and so helps reduce the quantity of water which needs to be recovered or delivered to achieve given environmental outcomes.
On the advice of the MDBA, NSW is considering the relaxation of constraints in five key areas:
- The Gwydir valley
- The Hume to Yarrawonga reach of the Murray (in partnership with Victoria)
- The Yarrawonga to Wakool reach of the Murray
- The Murrumbidgee, and
- The Lower Darling.
The easing of constraints in these areas is expected to support the reconnection of floodplains and wetlands to the main river channel, supporting ecosystem services and providing water and environmental cues to prompt breeding cycles in a range of fauna and flora.
NSW has put together concept proposals for the relaxation of constraints in the Gwydir, the Yarrawonga to Wakool reach, and the Murrumbidgee, while the MDBA put together a business case on the Hume to Yarrawonga reach on behalf of Victoria and NSW. The relaxation of constraints in the Lower Darling is being considered as part of the broader Menindee Lakes SDL project.
It is a cornerstone of NSW policy that all constraints projects will be subject to the mitigation of unacceptable third party impacts before the projects are implemented.
To ensure all unacceptable impacts are identified prior to implementation, the NSW Government will undertake a substantial community engagement program as part of the detailed design stage for each of the projects. In some cases, this engagement process is expected to take place over a period of years, through a range of media, to ensure that engagement is completed effectively. The department is now undertaking early planning towards this engagement process, but further progress is contingent upon receiving Commonwealth funding for the projects.
Factsheets on the Murrumbidgee, Hume to Yarrawonga, and Yarrawonga to Wakool constraints management strategies will be released shortly. Details of the Lower Darling strategy will be addressed as part of the development of the Menindee Lakes SDL project. The strategy for the Gwydir is being reassessed in light of the disallowance of the Northern Basin Amendment to the Basin Plan by the Australian Senate.