Macquarie-Wambuul Water Security Project

The Macquarie-Wambuul Water Security Project is preparing a full business case to investigate options to strengthen town water security for Dubbo and the Macquarie-Castlereagh region during periods of severe drought.

The following 4 infrastructure options were initially identified for consideration:

• a regional pipeline connecting Dubbo to Nyngan and other towns
• using some of Burrendong Dam’s flood mitigation zone to increase water storage
• a new weir to potentially replace Gin Gin Weir located between Warren and Narromine
• other options identified in the regional water strategy, including consideration of accessing groundwater during a drought.

Following stakeholder consultation and assessment, a groundwater-based option has been identified for further investigation. The option would increase Dubbo Regional Council’s access to groundwater during severe drought and includes potential additional groundwater bores and associated pipeline south of Dubbo connecting to the existing water treatment plant.

The project has now moved into further investigations to inform the full business case. No decision has been made to construct the proposed infrastructure.

For more information about the Macquarie Wambuul Water Security Project, download the March 2026 fact sheet (PDF, 174 KB).

Project location

The Macquarie-Wambuul River system is part of the Macquarie-Castlereagh catchment in central west NSW, within the traditional lands of the Gomeroi/Kamilaroi, Ngemba, Ngiyampaa, Wailwan and Wiradjuri people.

The river flows from the Great Dividing Range near Bathurst, north-west past Wellington, Dubbo, Narromine and Warren to meet the Barwon River upstream of Brewarrina. It includes the Macquarie Marshes, an internationally significant wetlands area.

Project timeline

The Macquarie-Castlereagh region is experiencing more frequent and severe drought, increasing pressures on water security. There is a need to:

• improve town water security in the region
• deliver water more efficiently to high-priority needs
• maintain environmental flows in the system, including to the Macquarie Marshes
• improve the drought resilience of industry, including meat processing and agriculture.

The shortlisted option will increase Dubbo's access to groundwater during severe drought when water levels in Burrendong Dam are critically low.

During extended drought, groundwater can provide an important backup water source. The shortlisted option includes new infrastructure and operating arrangements that would allow access to additional groundwater when needed.

Increasing access to groundwater during drought would improve water reliability for Dubbo, reduce reliance on Burrendong Dam and help preserve surface water supplies for downstream communities such as Nyngan and Cobar.

Work is currently underway to further assess the viability of this option, including what infrastructure will be required and to assess regulatory pathways including:

• Infrastructure investigations – assessing what new infrastructure may be required, that is expanding the bore network south of Dubbo and constructing a pipeline connecting to the water treatment plant. This work ensures groundwater can be accessed at the scale needed during extreme drought conditions.
• Licensing and regulatory assessments – examining how temporary access to additional groundwater could operate during extreme events, including the rules and approvals designed to safeguard the aquifer and ensure any potential effects on other groundwater users are appropriately managed.

These assessments will be used in the full business case to understand their economic, social and environmental costs and benefits to help inform future government funding decisions.

Site investigations

Site investigations are expected to commence from Tuesday 8 September 2026 to help better understand local conditions and inform concept design, costing and preparation of the full business case.

Areas south of Dubbo have been identified for further investigation based on hydrogeological assessments, including:

• The productivity of the aquifer
• Opportunities to distribute groundwater extraction and reduce pressure on existing bores
• The ability to efficiently connect potential groundwater infrastructure to Dubbo’s existing water supply network

Investigations will include geotechnical, environmental and cultural heritage assessments.

Environmental and cultural heritage assessments are non-intrusive and involve specialist contractors walking across identified investigation areas to observe, photograph and record relevant environmental and cultural heritage features.

Geotechnical investigations will be undertaken with the road reserves along:

• Macquarie Street between Dubbo Water Treatment Plant and Margaret Crescent south of Dubbo
• Old Dubbo Road to Warrie Road south of Dubbo
• Warrie Road for the full length.

Geotechnical investigations will include digging shallow holes to collect soil samples for laboratory testing. These investigations will help the project team understand ground conditions and inform concept design, costing and preparation of the full business case.

Changed traffic conditions

Temporary changed traffic conditions will be in place while some investigations are undertaken. These may include reduced speed limits and traffic controls such as, signage, traffic lights and traffic controllers.

Conditions may change as the investigations progress. If you are in the area, please take care around work areas and follow traffic controls.

Project funding

The NSW and Australian governments are jointly funding $9.35 million to deliver a full business case for the project, with the Australian Government contributing through the National Water Grid Fund.

The funding will allow the NSW Government to deliver a focussed options analysis. Detailed technical studies will include economic, engineering, cultural heritage and environmental assessments. The Water Group will oversee this analysis and integrate stakeholder consultation to ensure the best infrastructure solutions are identified and progressed.

The outcomes of these studies and consultations will be included in the full business case, which will guide future funding decisions for the project by the NSW and Australian governments.

The full business case is intended to be finalised in early 2027.

Stakeholder engagement

We are committed to building and maintaining respectful, trusted and collaborative relationships with our communities and stakeholders to ensure water infrastructure projects achieve the best possible outcomes.

Community consultation plays an important role in developing any full business case, and we thank everyone who has shared their views as we’ve carried out this important work.

Working with landholders and groundwater licence holders

The department is contacting landholders and groundwater licence holders within and near the investigation area to provide information about the upcoming investigations and support ongoing engagement.

Where access to private property is required, the project team will contact the relevant landholders before any onsite activities commence to discuss the proposed investigations, timing, suitable access arrangements and any property-specific or bio-security requirements.

The department is also undertaking technical assessments and groundwater modelling to understand how potential additional groundwater extraction could interact with the aquifer and existing groundwater users, particularly during extended drought conditions.

Groundwater licence holders are encouraged to share local knowledge, questions or concerns about groundwater access and use so these can be considered as the investigations and full business case progress.

No decisions have been made regarding future infrastructure, groundwater extraction arrangements or project delivery.

What we heard

A What we heard report capturing feedback from community engagement between 2024 and early 2026 is now available. 

The report outlines responses from key stakeholders, First Nations groups and the broader community to the 4 options being explored as part of preparing the full business case.

The report includes: 

• an overview of the engagement process and participation by community and stakeholders
• a summary of what we heard on key options proposed and our responses to the feedback received.
   

Community and stakeholder engagement will continue throughout future groundwater assessment phases to better understand potential opportunities and impacts, and until the business case is finalised. We will keep sharing updates on the feedback received, including publishing What We Heard reports. 

View the presentation slides