About the project
The Minimum Inflows project has developed a method to consider the risk of climate change and variability in the water allocation process. It will review the water that flows into dams during drought and may adjust how much water is set aside in dams to meet high-priority needs under a future climate conditions.
The review will be carried out in all regulated river water sources.
Project benefits
The project will inform the minimum amount of water required to set aside in storages to meet high priority needs under different climate scenarios.
This will provide:
- more certainty to water users by improving the capacity of water sharing plans to manage water availability under a more variable climate
- an improved understanding of the level of security for high priority users and the likelihood of the Extreme Events Policy being triggered.
The proposed method has been reviewed and endorsed by an expert panel convened by the Office of the NSW Chief Scientist & Engineer (OSCE).
There are 3 key statutory commitments that underpin this project:
- The requirement in regulated water sharing plans to undertake the review.
- NSW Water Strategy action 4.2 to undertake a review of water allocation and water sharing in response to new climate information.
- Ministerial commitments made as an outcome of the discontinuance of the Border Rivers Water Sharing Plan judicial review
Minimum Inflow review method
We have developed a minimum inflows review method to incorporate the risk of climate change and variability into the water allocation process.
The OSCE has reviewed and endorsed the revised method and made 13 recommendations. Our response to the OCSE review outlines how we have addressed the feedback and recommendations.
The department has updated the method to include updated information and address OCSE feedback. The method will be progressively applied to all regulated river water sources
Public information sessions
You can register for an information sessions on the method and the department’s response to the OCSE review.
When: Wednesday 11 March 2026
Time: 12pm – 1:30pm
When: Monday 30 March 2026
Time: 12pm – 1:30pm
Next steps
Further consultation will occur on the valley specific analysis and options for the northern basin regulated river water sources in early 2026 and then on final changes to the water sharing plans in mid-2026. Consultation on the analysis for the Southern and Coastal regulated river water sources will occur in a staged approach throughout late 2026 and 2027.
Supporting documents
| Document name |
|---|
| Minimum inflows: Technical Review Method (PDF, 1.2 MB) |
| Response to the independent review of Minimum Inflows method (PDF, 432.29 KB) |
| Climate data for the Minimum Inflows project (PDF, 210.33 KB) |
Project background
The Millenium and Tinderbox (2017-2020) droughts saw record low inflows across many parts of NSW. This resulted in the suspension of water sharing plans, triggered the Extreme Events policy and required emergency drought measures such as shortening rivers, bulk water deliveries, ceasing replenishment flows and suspending water for lower priority water users. Allocations to high priority licences were also reduced. This caused uncertainty for all water users, environmental impacts and water quality issues. Following the Tinderbox drought, there has been significant community concern about climate change impacts on future water supplies and whether our current allocation method provides an appropriate level of security for high priority water needs, including licensed and unlicensed Basic Landholder Rights, critical environmental needs, town water supplies and high security licences.
Current allocation method
Water held in storages in regulated river systems are distributed with an available water determination or water allocation. This process reserves an amount of water to secure supply to high priority water needs and shares the water above this reserve to other users. Minimum inflows are considered a resource in the allocation process and are defined as the assumed minimum amount of inflow that will occur based on the worst drought on record as of the first water sharing plan. For most regulated systems, this was 2004.