Menindee Lakes Water Saving Project

The Menindee Lakes Water Saving Project aims to enhance the significant natural and cultural values of the Menindee Lakes while delivering on NSW Government’s commitment to the Murray Darling Basin Plan to adjust the sustainable diversion limit by reducing evaporative losses.

It is an opportunity to improve the efficiency of the Menindee storages and achieve environmental outcomes for the southern Murray Darling Basin.

The project is at a concept plan stage only and is not expected to be complete until 2024. During this time, extensive engagement with stakeholders and the community will be undertaken in order to assist with the ongoing development of the project.

The project currently consists of a package of proposed infrastructure works and measures that will deliver water efficiency savings, better river operations, and improved environmental outcomes at the same time as benefiting communities.

October 2018 Engagement Summary Report Release Update

Between 29–31 October 2018 the NSW Land and Water Commissioner coordinated and facilitated meetings between the Department of Industry Water and community groups and stakeholders in the Lower Darling region to provide information and gain feedback on the proposed Menindee Lakes Water Saving Project.

With nearly 400 people participating, the Department received a significant amount of feedback during these meetings. The Departments initial expectation and commitment was to release a summary report from the consultation before the end of 2018. The report is currently in the review process and it is anticipated that it will be released in the coming weeks.

About the project

Further project information can be found in the following links:

Fact sheets

Frequently asked questions

How can stakeholders and the community get involved?

The NSW Government will consult extensively with water users and the community around the Menindee Lakes and Lower Darling on potential future management options for the lakes before any approach is finalised.

Engagement with stakeholders, landholders, and community members to incorporate various views, knowledge, and input into the ongoing development of the project is a key component toward its success.

Engagement will take place through a range of means; including stakeholder advisory panels, information sessions, and formal submission processes for both the Environmental Impact Statement and any amendments to relevant water sharing plans.

Targeted engagement is also expected to focus on issues such as (but will not be limited to) the proposed riparian flow regime for the Lower Darling, the Anabranch flow regime and mitigation measures, and the Lower Darling constraints relaxation measures.

All engagement activities will be conducted in a timely, transparent, and equitable manner. We will give specific dates and details of various engagement activities at appropriate stages of the project’s development.

What is the Menindee Lakes Water Saving Project?

The Menindee Lakes Water Saving Project (the project) is a package of proposed works and measures that aims to deliver better river operations, improved environmental and socioeconomic outcomes and water efficiency savings. It is a sustainable diversion limit (SDL) adjustment mechanism project under the Murray–Darling Basin Plan that is currently at concept design stage.

Through the proposed works and measures, the project will also help overcome system constraints and improve the ability for operators to achieve higher flow events in the Lower Murray.

Numerous proposals for changes to the Menindee Lakes have been under consideration for a number of years. An early proposal for the lakes was submitted to the Murray–Darling Basin Authority (MDBA) in 2016. This was modified, following confirmation of the Wentworth to Broken Hill Pipeline, the structural adjustment and removal of irrigation demand at Tandou in the Lower Darling by the Commonwealth Government and further advice from the MDBA on options that would enhance water savings and the SDL adjustment volume overall. The published preliminary business case reflects these changes.

The project seeks to achieve significant water savings by further investigating the current proposal including:

  • allowing Lake Menindee to be operated independently of Lake Cawndilla, and ceasing to use Lake Cawndilla for water storage in all but the wettest years
  • considering alternative options for water security in the Lower Darling
  • permitting faster drawdown of water in Lake Menindee, including providing access to residual water
  • enlarging the outlet structure and constructing a drainage channel in the bed of Lake Menindee
  • increasing flexibility of supply by preferentially retaining water in the more efficient Lakes Wetherell and Pamamaroo
  • accommodating higher managed flows in the Lower Darling through works to:
    • manage breakouts onto the floodplain and into dry lakes and anabranches
    • protect private infrastructure from being impacted by higher flows, including changed operational rules to complement structural works.

We anticipate that there will be further changes to this proposal to increase social amenity and environmental outcomes as a result of consultation with the community, further studies and the environmental assessment process.

Why have the Menindee Lakes been selected by the Murray–Darling Basin Plan as a water savings opportunity?

Before the modification of the lakes in the 1950s and 1960s to provide a storage system, the lakes would naturally fill during high river flows and subsequently recede, forming a series of pools that would periodically evaporate entirely. The alteration of the lakes through the addition of weirs, regulators, levees, and channels to allow the storage and release of water has substantially changed this natural regime. On average the Menindee Lakes lose 426 gigalitres of water annually to evaporation. Up to 700 gigalitres can be lost to evaporation annually when the lakes are full.

Each lake also contains a percentage of ‘dead storage’ that cannot be accessed for consumptive use, and may therefore also be lost to evaporation. This “dead storage” is estimated at more than 119 gigalitres for the four main lakes.

If evaporative water loss from the Menindee Lakes could be reduced, significantly more water could be made available for the environment.

As well as being a significant source of water for local towns and users, the lakes are also located in an area of environmental, social and cultural significance, and provide recreational, tourism and economic opportunities for the towns and surrounding region.

The Menindee Lakes System is an ecologically significant area of the Murray–Darling Basin, providing key habitat for aquatic fauna, including important nursery grounds and recruitment hotspots that support native fish populations of the Barwon, Darling and Murray Rivers, with the natural wetting and drying cycle of the lakes being a key driver of primary productivity in the Lower Darling and fish movement into the northern basin.

Since their modification, the Menindee Lakes have generally been operated to maximise the storage volumes, water quality, and ability to supply users, and to minimise evaporation and mitigate floods where possible. Since the 1990s, operations have also focused on providing ecological benefits, managing flood mitigation for the Lower Darling to provide environmental benefits, controlling foreshore erosion, and minimising erosion of cultural heritage sites.

Regulation of the lakes has increased sedimentation, reducing accessibility of water, and has also altered the flow regime in the Lower Darling, reducing the frequency of overbank flow events and freshes.

There are a range of ecological targets associated with the flow regime for the Lower Darling floodplain that are currently difficult to meet because of existing operational constraints including regulator capacities and operational policy, and the need to ensure reliability of local town water supply.

Altering the existing operational strategies and constructing new or modified infrastructure has the potential to address many of these issues, while providing water savings to meet NSW’s commitments under the Basin Plan.

How will the project help to meet targets set by the Murray–Darling Basin Plan?

The project would allow for water to be concentrated in the more efficient upper two lakes, which would reduce the amount of water lost due to evaporation. The larger Menindee Lake outlet would also contribute to water savings by enhancing the rate of drawdown of the lake and reduce evaporative losses.

The proposed changes would help to minimise evaporation from the lakes, while ensuring efficient supply and delivery of water for both users and the environment. This in turn would allow us to respond more flexibly to changing climatic conditions now and into the future.

The Murray–Darling Basin Authority’s modelling suggests that the Menindee Lakes Water Savings Project will deliver average water savings of around 106 GL per year. These water savings would be available for environmental outcomes.

The water savings means less water needs to be taken out of productive use in NSW in order to meet NSW’s share of water recovery. Water saved will not be used to underpin increases in upstream irrigation entitlements or diversion limits.

Further information is available at the Murray Darling Basin Plan.

What are the potential benefits of the project?

The project is expected to provide significant benefits as a result of the proposed infrastructure works and measures. These benefits may include, but may not be exclusive to:

  • an increase in the frequency and duration of small overbank flows to sustain and improve floodplain health and the connections between areas of habitat while also contributing to improved flows in the Murray River
  • increased average river flows into the Lower Darling, helping to deliver environmental benefits for a range of ecosystems
  • new fishways to allow up- and down-stream movement for native fish to assist in overcoming existing barriers to fish passage
  • reinstatement of the natural drying cycles of the Lake Wetherell floodplain, restoring more natural conditions and therefore benefiting the flora and fauna that inhabit the lake shore environments
  • employment opportunities in the Menindee Lakes region during the period of delivery, particularly during the detailed design and construction phases. In particular, the project will support the NSW policy of seeking greater participation by Aboriginal people in government construction projects.

How is the NSW Government consulting the community in decisions about the project?

NSW Government understands that, as well as being a significant source of water for local towns and users, the lakes are also located in an area of environmental, social and cultural significance, and provide recreational, tourism and economic opportunities for the towns and surrounding region.

The NSW Government will consult extensively with water users and the community around the Menindee Lakes and Lower Darling on potential future management options for the lakes before any approach is finalised, and further details will be available soon.

How is the NSW Government considering Aboriginal Cultural Heritage aspects of the project?

The Barkandji People hold native title rights and interests in the Lower Darling River and Menindee Lakes system so the project needs to comply with the Commonwealth Native Title Act 1993.

Works completed to date have indicated that more than 400 registered Aboriginal sites are located within the proposed project area.

The NSW Government will ensure sites with Aboriginal cultural heritage significance are managed appropriately. Consultation with local Aboriginal communities and cultural heritage site surveys will be required as part of the assessments and approvals processes.

In addition, we will talk to the Aboriginal community about establishing an Aboriginal Advisory Committee as part the governance arrangements for the project so that Aboriginal peoples’ input will be considered in the ongoing development of the project.

Further, the NSW Government recognises that water is critical for social, environmental, economic and cultural health and well-being.

Water is protected in legislation. The water laws establish statutory water sharing plans to deliver balanced outcomes for water users and the environment. Social and Cultural objectives are included in water sharing plans.

NSW is currently revising the water sharing plan objectives to enable improved reporting on the performance of water sharing plans.

Where can we find information on changes to metering and water sharing plans?

There have been a number of changes to metering and water sharing plans within recent years. Information on the changes to metering and water sharing plans can be found on the following websites:

What measures is are being taken by the NSW government to better manage water in the northern rivers of the Murray Darling Basin?

The NSW government is committed to improving the way in which we manage environmental water in the NSW northern Murray Darling Basin. The New South Wales and Commonwealth Governments have invested public funds in recovering water for the environment.

Environmental water must be better managed to maximise environmental outcomes that improve the health of the Basin. An Interagency Working Group (IWG) with New South Wales and Commonwealth agency representation was established in February 2018 to develop options on how the NSW government can better manage environmental water. The NSW government is progressing the recommendations of the IWG’s interim solutions package to better manage environmental water. Further information is available at Better Management of Environmental Water.

What measures is the NSW Government taking to manage floodplain harvesting?

In 2013, the NSW Government introduced the Floodplain Harvesting Policy to stop unconstrained floodplain harvesting by bringing it into a licenced framework. The policy is currently being implemented in the designated floodplains of the five northern valleys. It will then be rolled out across the state. Further information is available at Floodplain Harvesting.

How are Menindee Lakes system currently operated?

Since their modification, the Menindee Lakes have generally been operated to maximise the storage volumes, water quality, and ability to supply users, and to minimise evaporation and mitigate floods where possible.

Since the 1990s, operations have also focused on providing ecological benefits, managing flood mitigation for the Lower Darling to provide environmental benefits, controlling foreshore erosion, and minimising erosion of cultural heritage sites.

The Menindee Lakes storage is owned and operated by New South Wales with a long standing arrangement under the Murray Darling Basin Agreement. This Agreement requires the Murray Darling Basin Authority (the MDBA) to include the water held within the lakes as part of the shared resource of the River Murray System, and use the water in the lakes when the volume is above 640 GL until it next falls below 480 GL.

Once the total volume of the lakes falls below 480GL, the held water is no longer considered a shared resource of the River Murray System and the water is managed by New South Wales to meet local demands. Some of the water within the Menindee Lakes system is considered dead storage and cannot be accessed for release. The dead storage volume within the system is 125 gigalitres.

To ensure critical water supply needs can be met during periods of low inflows as well as to minimise evaporative water losses, Lakes Wetherell and Pamamaroo are preferentially used to store water ahead of Lakes Menindee and Cawndilla. In most instances, water released to meet immediate consumptive demands comes initially from Lake Menindee, then Lake Cawndilla and Lake Wetherell.

As in other catchments, water is supplied according to the order of priority of licences, particularly during periods where water availability is limited and use may need to be restricted to protect water for critical needs. This protection of stored water can become particularly crucial as water volumes drop, and as evaporative losses become more significant and water salinity increases.

In an extended period of low inflows, the salinity can become sufficient to make the water in the lakes unsuitable for irrigation or town water supply regardless of availability. It does, however, remain an important refuge habitat for aquatic and terrestrial fauna until the next major inflow.

During periods of flood, the lakes are operated to maintain the structural integrity of existing infrastructure, to maintain the security of existing water entitlements, and to minimise damage to downstream properties where possible.

Inflows are managed based on a series of considerations including water quality, levee bank stability and pre-releases to mimic a more natural flow pattern. Water can also be transferred from Lake Menindee to Lake Victoria in the Lower Murray under a ‘harmony operation’ if flows in the Lower Murray are not meeting consumptive and environmental demands for water. Water for additional dilution flow procedures can also be called from the lakes during periods of storage excess.

Have your say

The NSW Government is committed to working with stakeholders and communities to improve the management of our water resources for communities, the environment, culture and heritage and the economy.

Engagement with stakeholders, landholders, and community members to enable incorporation of various views, knowledge, and input into the ongoing development of the project remains a key component of its success.

Engagement will take place through a range of means, including Stakeholder Advisory Panels, information sessions, and formal submission processes for both the Environmental Impact Statement and any amendments to relevant Water Sharing Plans.

It is intended that all engagement activities will be conducted in a timely, transparent, and equitable manner. Specific dates and details on various engagement activities will continue to be advised at appropriate stages of the project’s development.