What is the North-South Connectivity Trial?
The Basin Officials Committee (BOC) facilitates cooperation and coordination between the Commonwealth, the Basin states and the Murray–Darling Basin Authority (MDBA) in funding works and managing the Basin water and other natural resources.
BOC has approved a trial to protect environmental water recovered in the northern Basin that arrives at the Menindee Lakes, and shepherd that water through to the southern Basin.
The trial is testing water accounting arrangements to protect this water while ensuring no impact to other entitlement holders. BOC has approved the trial arrangements until 30 June 2028. This includes requirements for monitoring and review throughout the trial period.
New South Wales (NSW) and Victoria have an equal share of inflows into the Menindee Lakes under the Murray-Darling Basin Agreement. Both States need arrangements in place to support the trial and protect the water for environmental use downstream.
The trial refers to the environmental water arriving at the Menindee Lakes as ‘Active Environmental Water’ (AEW). This is because NSW must ‘actively’ manage the water in the upstream Barwon-Darling River.
NSW does this through tracking daily inflows and changing licenced pumping thresholds as the water flows down the river.
The amount of AEW will vary from year to year. The MDBA undertook modelling as part of the Northern Basin Review in 2016. From this modelling, the MDBA estimates that the long-term average volume of AEW reaching the Menindee Lakes is about 150 giga litres/year. Victoria’s share is equal to half this estimated amount (75 giga litres/year).
Estimates of the long-term average of AEW reaching the Menindee Lakes will continue to improve as knowledge of environmental water delivery improves and implementation of the Basin Plan continues.
This additional environmental water flowing to the Menindee Lakes and through to the River Murray System will enable a range of additional environmental outcomes in NSW, Victoria and South Australia.
What has VEWH applied for?
The Victorian Environmental Water Holder (VEWH) has applied to amend its Flora and Fauna Bulk Entitlement (BE) to protect Victoria’s share of the northern Murray-Darling Basin ‘Active Environmental Water’ that reaches the southern Basin, via the Menindee Lakes.
Victoria is entitled to half of all inflows to the Menindee Lakes under the Murray-Darling Basin Agreement. The proposed amendments would bring this water under Victoria’s entitlement framework through the introduction of a new ‘Menindee Lakes Trial Entitlement’ under the Flora and Fauna BE.
If approved, VEWH would be required to manage the entitlement consistent with its functions under the Water Act 1989 and consistent with the conditions of the North-South Connectivity Trial agreed by BOC in November 2025.
The proposed bulk entitlement amendment also provides for VEWH to continue to access this water if BOC approves enduring arrangements. No water will be available to the VEWH under the proposed amendment if for any reason the trial ceases without an agreed extension or without BOC approved enduring arrangements in place.
The VEWH is also seeking minor administrative changes to the Flora and Fauna BE. For instance, updating the title and current functions of the Resource Manager and removing a redundant explanatory note for the Barmah-Millewa Forest Environmental Water Allocation.
How would this water benefit the environment?
The proposed amendments to protect Victoria’s share of AEW would increase available environmental water which would enhance environmental outcomes and deliver on the objectives of the Murray-Darling Basin Plan.
In-channel habitat for native fish and other water dependent animals would benefit from the additional flow into the southern Basin. Fringing, in-stream and floodplain vegetation would benefit both immediately downstream of the Menindee Lakes and throughout the lower Murray, including in Victoria’s Lindsay, Mulcra and Wallpolla islands waterways.
The additional water could also provide greater flexibility in using environmental holdings across the River Murray System, achieving better outcomes.
For example, improved landscape-scale outcomes could be achieved by coordinating releases from the upper River Murray storages to coincide with releases from the Menindee Lakes, providing sufficiently sized river pulses to trigger fish spawning events across the River Murray System.
How is Victoria ensuring that water users are not impacted?
The MDBA has undertaken analysis and provided assurances to BOC that Victorian water availability would not be adversely impacted by protecting this Active Environmental Water under the trial.
VEWH’s proposed bulk entitlement amendment includes various risk mitigation measures to further ensure this, consistent with the trial arrangements agreed by BOC.
This includes the setting aside of a contingency reserve, a condition that the AEW would spill first during a physical spill of the Menindee Lakes, and that VEWH and Victoria’s Resource Manager for the River Murray must develop operating arrangements consistent with the conditions and requirements of the trial.
How would use of this water be managed?
Delivery would occur in line with the VEWH’s annual Seasonal Watering Plan. The VEWH works in close partnership with environmental water managers in NSW, South Australia, the Commonwealth Environmental Water Holder and the Living Murray program through the Southern Connected Basin Environmental Watering Committee to coordinate flows across the southern Murray Darling Basin.
The VEWH would manage the water under these established planning and delivery partnerships to achieve environmental outcomes as efficiently as possible. The VEWH would also work directly with the holder of NSW’s share of Active Environmental Water inflows to jointly manage the water, as per the trial arrangements.
