Seasonal determination increases for the Murray, Goulburn and Loddon systems

Seasonal determination increases for the Murray, Goulburn and Loddon systems

The Resource Manager for northern Victoria today announced an update of 2025/26 seasonal determinations.

The Murray system seasonal determination increases from 49 per cent of high-reliability water shares (HRWS) to 53 per cent HRWS. The Goulburn and Loddon systems increase from 38 per cent HRWS to 39 per cent HRWS.

The Campaspe system remains at 100 per cent HRWS. The Broken and Bullarook systems both remain unchanged at 0 per cent HRWS.

Resource Manager Mark Bailey said there had been limited flows into the storages in recent weeks.

“Flows into the storage have been close to our estimates in the absence of any significant rainfall since the last assessment,” Dr Bailey said. “Additional flows into the Menindee Lakes contributed to the increase in the Murray system.

“All operating requirements in the Broken system are now fully established for the season. Further resource improvements will contribute to seasonal determinations.

“More rainfall is needed in the Bullarook system over the coming weeks to secure the system’s operating requirements and increase seasonal determinations.”

Outlook for the 2025/26 Season

The outlooks for 2025/26 seasonal determinations are based on historical flow records that have been adjusted to match climate conditions observed since 1975. The outlook scenarios presented are:

• Wet                 Inflow volumes to major storages that are greater in 10 years out of 100
• Average          Inflow volumes to major storages that are greater in 50 years out of 100
• Dry                  Inflow volumes to major storages that are greater in 90 years out of 100
• Extreme Dry   Inflow volumes to major storages that are greater in 99 years out of 100

The following tables summarise possible high-reliability water share seasonal determinations through the season and include a reference year to help users recognise the possible inflow conditions.

Murray System Outlook for Seasonal Determination of High-Reliability Water Shares

Goulburn and Loddon System Outlook for Seasonal Determination of High-Reliability Water Shares

Broken System Outlook for Seasonal Determination of High-Reliability Water Shares

Bullarook System Outlook for Seasonal Determination of High-Reliability Water Shares

Seasonal determinations under additional scenarios for each system are available from the Additional Scenarios webpage. 

Upcoming Resource Manager Announcements

• The next 2025/26 seasonal determination announcement will be released on Monday, 1 September 2025.
• The risk of spill in the Murray and Campaspe systems will be updated on Wednesday, 10 September 2025.