Northern Victorian Resource Manager Releases 2025/26 Seasonal Determination Outlook
The Resource Manager for northern Victorian water systems today released the first outlook for 2025/26 seasonal determinations.
Resource Manager Mark Bailey said the reserves established this season provided a good foundation for water availability in most systems during 2025/26.
“The Murray, Goulburn, and Loddon systems should begin the 2025/26 water year with seasonal determinations of about 25 per cent high-reliability water shares (HRWS) or better,” Dr Bailey said.
“This is based on the availability of reserves and estimated use through the remainder of 2024/25.
“The Campaspe system should receive 100 per cent HRWS on 1 July 2025 under all inflow conditions due to the reserves established this year.
“As annual systems, the seasonal determinations in the Broken and Bullarook systems rely on catchment conditions and the volume of carried over allocation.
“We anticipate both the Broken Bullarook systems starting 2025/26 at zero per cent HRWS.
“Inflow conditions during 2025/26 will determine how seasonal determinations change during the year. Average inflow conditions should allow the Murray, Broken, Goulburn, Loddon and Bullarook systems to reach seasonal determinations of 100 per cent HRWS by mid-October 2025.
“The risk of spill in the Murray, Goulburn and Campaspe systems in 2025/26 will depend on how much water is released from the storages in the next few months to meet demands. The risk of spill in the Murray system is expected to be about 50 per cent at the start of July 2025. The risk of spill in the Goulburn system is expected to be about 30 per cent and 45 per cent in the Campaspe system in early 2025/26.
“Customers in these systems should factor the risk of spill into their plans for the remaining months of 2024/25.”
Further detail on outlook for the 2025/26 Season
The Bullarook seasonal determination outlook for 2024/25 is 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 table summarises 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
| Wet |
74% |
100% |
100% |
100% |
| Average |
50% |
66% |
100% |
100% |
| Dry |
31% |
42% |
60% |
91% |
| Extreme Dry |
26% |
32% |
35% |
39% |
Goulburn and Loddon System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
74% |
100% |
100% |
100% |
| Average |
41% |
70% |
100% |
100% |
| Dry |
34%
|
42% |
59% |
77% |
| Extreme Dry |
32% |
34% |
37% |
42% |
Broken System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
51% |
63% |
100% |
100% |
| Average |
0% |
63% |
100% |
100% |
| Dry |
0% |
0% |
0% |
6% |
| Extreme Dry |
0% |
0% |
0% |
0% |
Bullarook System Outlook for Seasonal Determination of High-Reliability Water Shares
| Wet |
0% |
100% |
100% |
100% |
| Average |
0% |
100% |
100% |
100% |
| Dry |
0% |
0% |
0% |
0% |
| Extreme Dry |
0% |
0% |
0% |
0% |
Seasonal determinations under additional scenarios for each system are available from the .
Upcoming Resource Manager Announcements
- The next 2024/25 seasonal determination announcement will be released on Monday, 3 March 2025.
- The 2025/26 seasonal determination outlooks will be updated on Thursday, 15 May 2025.
- The first 2025/26 seasonal determination announcement will be released on Tuesday, 1 July 2025 and will include an updated outlook and an assessment of the probability of spill in the Murray, Goulburn and Campaspe systems.