Across the Murray-Darling Basin, there are physical and operational barriers - or “constraints” – that limit the flows that can be delivered and the outcomes that can be achieved. (Glossary) Physical constraints include things like roads, bridges and private land that would be flooded at higher flows, causing damage and affecting access. Operational constraints include arrangements and processes, such as channel sharing, water accounting and the ability to order water from specific locations.
Constraints Management Strategy
The Murray-Darling Basin Authority’s Constraints Management Strategy, released in 2013, set out seven key areas where physical constraints need to be addressed to maximise the benefits of environmental water delivery in the southern connected Basin.
This strategy looked at ways to address these constraints, including raising the height of bridges to maintain access at higher flows, improving flood warning systems and purchasing flood easements to enable private land to be watered. The outcomes that can be achieved in each reach will depend on addressing constraints in the system; a better understanding of the links and interdependencies across the basin is needed.
We are committed to delivering environmental outcomes across the Basin. However, the Victorian Government recognises that any relaxation of constraints will pose third party flooding related risks which can impact public and private land, infrastructure, stock and people.
Victoria will not:
- flood private property without consent, or
- undertake compulsory acquisition of land or easements.
We can enhance natural higher flow events by putting in place measures that prevent and mitigate any potential impacts associated with higher flows on public and private land. These measures require agreement by affected landholders.
One constraints project, the Hume to Yarrawonga measure, is included in Victoria’s package of 22 offset projects.
Independent Review Commences into MDBA Constraints Modelling
At the December 2018 Murray-Darling Basin Ministerial Council, Ministers requested that community concerns about deliverability of proposed higher flows be addressed as a priority. These community concerns were not progressed to the satisfaction of Victoria and NSW. At the subsequent August 2019 meeting Victoria and NSW agreed to appoint independent experts to undertake a review of the modelling of constraints to understand how they can be delivered in a real-world context, create transparency and to confirm ecological outcomes.
On 16 December 2019, the Independent Expert Panel Review of Constraints Modelling (the Panel) submitted its report to the Victoria and NSW Ministers for Water. For the past three months the Panel has considered whether the existing modelling undertaken for the constraints program is sufficient to give communities confidence that it is practical to deliver the targeted flow rates (notified flow rates). The review has been conducted in accordance with the terms of reference.
What are the Panel's Terms of Reference?
The terms of reference of the Panel can be found by clicking here (PDF, 626.8 KB).
The Panel will consider whether the existing models and modelling results provide adequate information for:
- Assessing and communicating third party risks
- Informing the development of detailed design of flood mitigation measures and determining associated costs
- Articulating environmental outcomes associated with constraints projects
- Quantifying the change in system operator risk and increased risk of inadvertently flooding landholders
- Supporting operational real time decision making. This includes piggybacking and synchronising operating system releases, within and across the southern connected basin.
- The extent to which use of the environmental portfolio relies on implementation of constraints measures.
NSW and Victoria have asked that the Panel recommend strategies and future work to address any areas where current modelling cannot satisfy these requirements.
A second independent review was also agreed to at the August Ministerial Council meeting, by all water Ministers to establish an independent panel to peer-review the Murray River Capacity Risks Project to understand whether it is addressing the right tasks to the appropriate standard and timeframes.
The Panel convened a series of workshops to consult with modelling, operational and environmental experts from Victorian and NSW state departments and agencies and the Murray-Darling Basin Authority. The panel drew on additional experts in Basin Plan modelling, River Murray operations, floodplain hydrology and ecology in undertaking their review.
The panel did not directly interact with communities; however, worked closely with the relevant agencies to gain insights to inform the findings of the review. The review is a technical review of the modelling that underpins the Constraints Measures Program. The review assessed whether the existing modelling undertaken is sufficient to give communities confidence that it is practical to deliver the targeted environmental flow rates (notified flow rates), assess and manage risk and that the environmental outcomes are clear.
The Panel was announced on the 25 September and concluded on 16 December 2019.
The Panel reported directly to the Victorian and NSW Water Ministers with a view to discussing its findings and recommendations with other Basin governments at the next Ministerial Council to be held on December 17 2019.
The findings and recommendations will be used to inform Ministers’ decisions about remaining Basin Plan implementation activities associated with constraints projects, and will guide our next steps in co-designing constraints projects with communities in NSW and Victoria.
This project involves investigating opportunities to address physical constraints to the delivery of higher regulated flows – up to a maximum of 40,000 megalitres (ML) per day as measured at the Doctors Point streamflow gauge.
Investigations will examine the potential effects of higher flows on third parties and identify possible mitigation options with affected landholders to address unacceptable impacts. Possible options could be easements and/or infrastructure to allow the delivery of these flows to support improved river and wetland health outcomes. Landholder acceptance of potential works will be critical.
This project must be considered in relation to the other southern connected Basin constraints measures and is a joint initiative between Victoria and New South Wales.
Download the business case: Hume to Yarrawonga (PDF, 28.1 MB)
This project involves investigating opportunities to address in-channel constraints to the delivery of higher flows of up to 20,000 megalitres (ML) per day at Shepparton. Allowing the delivery of flows to the top of the bank would improve river health outcomes.
The work will be done in a staged and ‘bottom-up’ way with communities to understand the risks, impacts and costs, and develop feasible, practical and acceptable solutions to mitigate third party impacts. Building on this work, in close consultation with landholders and communities, further improvements to environmental water delivery will also be investigated. Landholder acceptance of potential works will be critical.
This project must be considered in relation to the other southern connected Basin constraints measures. This project is not included in the package of 22 offset projects put forward by the Victorian Government.
Page last updated: 07/06/21