Gunidgera Weir Raising

Gunidgera Weir Raising

About the project

WaterNSW is raising Gunidgera Weir to improve water delivery in the Gunidgera—Pian system in the Namoi valley.

Located on the Namoi River, the Gunidgera Weir is approximately six kilometres west of Wee Waa. The Gunidgera Weir and upstream regulator enable water flows to be stored, controlled and released from the weir pool into Namoi River and Gunidgera - Pian Creek.

Constructed in 1976, the Gunidgera Weir allows for control and regulation of water. The Project will increase the maximum diversion capacity from the Gunidgera Weir pool into the Gunidgera - Pian Creek system from 1230 megalitres per day (ML/day) to 1650 ML/day. This will increase WaterNSW’s ability to meet customers’ water needs in times of peak demand.

The proposed upgrade works will occur in two stages:

Stage 1 - Raising of the Gunidgera Weir by 0.47m and minor works at the Gunidgera Regulator and erosion control/protection works at Cotton Lane and Cudgewa Lane, within the first 12 km downstream of the Gunidgera Regulator.

Stage 2 - Monitoring, and where necessary, rectification works on the Gunidgera – Pian Creek System to manage the additional flows.

Stage 1 works will occur on land owned by WaterNSW, Council and Crown Lands. Access for construction will be through Cotton Lane and Cudgewa Lane.

Construction works have been postponed until 2022 due to high river flows in the Namoi that aren’t expected to subside before irrigation season. Stage 1 is now planned to begin in April 2022.


The Project will have a range of benefits that include:

  • Improving water delivery to Gunidgera-Pian customers during peak demand periods
  • Increasing capability for on-time delivery to customers
  • Limiting environmental impacts by maintaining the existing channel width (a previous option considered was widening the channel).

Project schedule

The construction works at Gunidgera Weir have been postponed until 2022, due to high river flows in the Namoi that aren’t expected to subside before irrigation season.

Due to drought impacting the region for the last three years, we expect that planting will be at a maximum in the coming season, so the WaterNSW project team has put a hold on the plans to deliver the project this year. We estimate starting works in April 2022.

Service Delivery impacts

Construction has been scheduled after the peak irrigation season to minimise service delivery impacts as far as reasonably practicable.

During construction, Gunidgera Weir's gates will be propped open to facilitate the weir raising works. Any flows resulting from localised catchment inflows will be passed down the Namoi river through Gunidgera Weir during construction.

Supplementary access to Gunidgera-Pian creek customers will not be possible when the works are occurring at the weir.

We expect the construction to take about 6 weeks for all of the works, but about four weeks on the actual weir.

We will provide further details on the exact timing and impacts on water delivery and river flows.


Customers have been consulted through the Namoi Customer Advisory Group (CAG) and River Operations Stakeholder Consultation Committee (ROSCCo).

The following stakeholders and government agencies have also been included in discussions:

  • Natural Resources Access Regulator (NRAR)
  • Department of Planning, Industry and Environment
  • Department of Primary Industries – Fisheries
  • Narrabri Shire Council

We will provide you with further information through project fact sheets and website updates.

Project updates

Contact details

For more information about Gunidgera Weir raising email us at or call 1300 662 077.

Project Manager: Sarinda Wickramasinghe


Thursday 02 December
2,494,850 ML
2,581,850 ML
9,154 ML
1,308 ML
30,186 ML
Thursday 02 December