Constraints relaxation in the NSW southern connected Murray Darling Basin

What is a constraint?

Under the Murray Darling Basin Plan, a constraint is a rule or structure which limits the volume and/or timing of the delivery of environmental water. Constraints can include physical structures (e.g. low-lying bridges), river management practices, and operational limits for river heights. Relaxing these constraints will:

  • allow better outcomes to be achieved with environmental water, and;
  • reduce the volume of water to be recovered to achieve environmental outcomes.

NSW constraints relaxation project

Implementation of constraints relaxation projects, agreed as part of the Constraints Measures Program under the Sustainable Diversion Limit Adjustment Mechanism (SDLAM), will determine impacts of increased flow rates required to deliver environmental water, negotiate preferred risk mitigation options with impacted landholders, and deliver on ground works to mitigate risks and remove constraints. In the southern connected Murray-Darling Basin there are four NSW SDLAM projects that will be the focus of constraints relaxation:

  • Hume to Yarrawonga reach of the Murray River (co-proponents with Victoria)
  • Yarrawonga to Wakool reach of the Murray River
  • Murrumbidgee key focus area
  • Lower Darling constraints measure (as part of the Menindee Lakes Water Saving Project)

Project details

Reach Current max regulated flow (ML/d) Notified Flow rate ML/d (including buffer) Potentially impacted properties/entities
Hume to Yarrawonga reach of the Murray 25,000ML at Doctor’s point 40,000 at Doctor’s Point

NSW - 101

Victoria - 106

Yarrawonga to Wakool reach of the Murray River 15,000-18,000 downstream Yarrawonga 30,000 (50,000) downstream Yarrawonga

NSW – 1649

Victoria - 118

Murrumbidgee key focus area 32,000* ML/d at Wagga Wagga 40,000 (45,000) at Wagga Wagga 1140
Lower Darling constraints measure 5,000 ML at Menindee Outlet 14,000ML at Menindee Outlet 210

* Current maximum environmental flow

To ensure all unacceptable impacts are identified prior to implementation, the NSW Government will undertake a substantial community engagement as part of the planning phase for each of the projects. The department is now undertaking early planning towards this engagement process.

Independent Expert Panel

The NSW and Victorian governments commissioned an independent review of the Murray - Darling Basin Authority’s (MDBA) modelling which underpins higher environmental flow delivery in the southern-connected Basin.

The review was undertaken by Greg Wilson (Chair), Campbell Fitzpatrick and George Warne.

The final report was provided to Ministers on 16 December 2019. Download and view the report.

View further information on the Independent review into MDBA constraints modelling.